chore: cargo fmt

This allows us to run with minimal priviledges in the Rosenpass process itself

.dockerignore

@@ -0,0 +1,7 @@
+examples/
+target/
+flake.*
+.ci
+.direnv
+.git
+.github

.github/workflows/qc.yaml

@@ -25,6 +25,34 @@ jobs:
       - name: Run ShellCheck
         uses: ludeeus/action-shellcheck@master
 
+  rustfmt:
+    name: Rust Format
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Run Rust Formatting Script
+        run: bash format_rust_code.sh --mode check
+
+  cargo-bench:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/cache@v3
+        with:
+          path: |
+            ~/.cargo/bin/
+            ~/.cargo/registry/index/
+            ~/.cargo/registry/cache/
+            ~/.cargo/git/db/
+            target/
+          key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
+      - name: Install libsodium
+        run: sudo apt-get install -y libsodium-dev
+        # liboqs requires quite a lot of stack memory, thus we adjust
+        # the default stack size picked for new threads (which is used
+        # by `cargo test`) to be _big enough_. Setting it to 8 MiB
+      - run: RUST_MIN_STACK=8388608 cargo bench --no-run --workspace
+
   cargo-audit:
     runs-on: ubuntu-latest
     steps:
@@ -93,7 +121,7 @@ jobs:
         # liboqs requires quite a lot of stack memory, thus we adjust
         # the default stack size picked for new threads (which is used
         # by `cargo test`) to be _big enough_. Setting it to 8 MiB
-      - run: RUST_MIN_STACK=8388608 cargo test
+      - run: RUST_MIN_STACK=8388608 cargo test --workspace
 
   cargo-test-nix-devshell-x86_64-linux:
     runs-on:
@@ -116,4 +144,35 @@ jobs:
         with:
           name: rosenpass
           authToken: ${{ secrets.CACHIX_AUTH_TOKEN }}
-      - run: nix develop --command cargo test
+      - run: nix develop --command cargo test --workspace
+
+  cargo-fuzz:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/cache@v3
+        with:
+          path: |
+            ~/.cargo/bin/
+            ~/.cargo/registry/index/
+            ~/.cargo/registry/cache/
+            ~/.cargo/git/db/
+            target/
+          key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
+      - name: Install libsodium
+        run: sudo apt-get install -y libsodium-dev
+      - name: Install nightly toolchain
+        run: |
+          rustup toolchain install nightly
+          rustup default nightly
+      - name: Install cargo-fuzz
+        run: cargo install cargo-fuzz
+      - name: Run fuzzing
+        run: |
+          cargo fuzz run fuzz_aead_enc_into -- -max_total_time=5
+          cargo fuzz run fuzz_blake2b -- -max_total_time=5
+          cargo fuzz run fuzz_handle_msg -- -max_total_time=5
+          ulimit -s 8192000 && RUST_MIN_STACK=33554432000 && cargo fuzz run fuzz_kyber_encaps -- -max_total_time=5
+          cargo fuzz run fuzz_mceliece_encaps -- -max_total_time=5
+          cargo fuzz run fuzz_box_secret_alloc -- -max_total_time=5
+          cargo fuzz run fuzz_vec_secret_alloc -- -max_total_time=5

Cargo.toml

@@ -3,8 +3,66 @@ resolver = "2"
 
 members = [
     "rosenpass",
+    "cipher-traits",
+    "ciphers",
+    "util",
+    "constant-time",
+    "oqs",
+    "to",
+    "fuzz",
+    "secret-memory",
+    "lenses",
+    "wireguard-broker",
+]
+
+default-members = [
+    "rosenpass",
+    "wireguard-broker"
 ]
 
 [workspace.metadata.release]
 # ensure that adding `--package` as argument to `cargo release` still creates version tags in the form of `vx.y.z`
 tag-prefix = ""
+
+[workspace.dependencies]
+rosenpass = { path = "rosenpass" }
+rosenpass-util = { path = "util" }
+rosenpass-constant-time = { path = "constant-time" }
+rosenpass-cipher-traits = { path = "cipher-traits" }
+rosenpass-ciphers = { path = "ciphers" }
+rosenpass-to = { path = "to" }
+rosenpass-secret-memory = { path = "secret-memory" }
+rosenpass-oqs = { path = "oqs" }
+rosenpass-lenses = { path = "lenses" }
+rosenpass-wireguard-broker = { path = "wireguard-broker" }
+criterion = "0.4.0"
+test_bin = "0.4.0"
+libfuzzer-sys = "0.4"
+stacker = "0.1.15"
+doc-comment = "0.3.3"
+base64 = "0.21.5"
+zeroize = "1.7.0"
+memoffset = "0.9.0"
+thiserror = "1.0.50"
+paste = "1.0.14"
+env_logger = "0.10.1"
+toml = "0.7.8"
+static_assertions = "1.1.0"
+allocator-api2 = "0.2.14"
+allocator-api2-tests = "0.2.14"
+memsec = "0.6.3"
+rand = "0.8.5"
+wireguard-uapi = "3.0.0"
+command-fds = "0.2.3"
+rustix = { version = "0.38.27", features = ["net"] }
+tokio = { version = "1.34.0", features = ["sync", "full", "mio"] }
+typenum = "1.17.0"
+log = { version = "0.4.20" }
+clap = { version = "4.4.10", features = ["derive"] }
+serde = { version = "1.0.193", features = ["derive"] }
+arbitrary = { version = "1.3.2", features = ["derive"] }
+anyhow = { version = "1.0.75", features = ["backtrace", "std"] }
+mio = { version = "0.8.9", features = ["net", "os-poll"] }
+oqs-sys = { version = "0.8", default-features = false, features = ['classic_mceliece', 'kyber']  }
+blake2 = "0.10.6"
+chacha20poly1305 = { version = "0.10.1", default-features = false, features = [ "std", "heapless" ] }

analysis/03_identity_hiding.entry.mpv

@@ -0,0 +1,121 @@
+/*
+  This identity hiding process tests whether the rosenpass protocol is able to protect the identity of an initiator or responder.
+  The participants in the test are trusted initiators, trusted responders and compromised initiators and responders.
+  The test consists of two phases. In the first phase all of the participants can communicate with each other using the rosenpass protocol.
+  An attacker observes the first phase and is able to intercept and modify messages and choose participants to communicate with each other
+
+  In the second phase if the anonymity of an initiator is being tested then one of two trusted initiators is chosen.
+  The chosen initiator communicates directly with a trusted responder.
+  If an attacker can determine which initiator was chosen then the anonymity of the initiator has been compromised.
+  Otherwise the protocol has successfully protected the initiators’ identity.
+
+  If the anonymity of a responder is being tested then one of two trusted responders is chosen instead.
+  Then an initiator communicates directly with the chosen responder.
+  If an attacker can determine which responder was chosen then the anonymity of the responder is compromised.
+  Otherwise the protocol successfully protects the identity of a responder.
+
+  The Proverif code treats the public key as synonymous with identity.
+  In the above test when a responder or initiator is chosen what is actually chosen is the public/private key pair to use for communication.
+  Traditionally when a responder or initiator is chosen they would be chosen randomly.
+  The way Proverif makes a "choice" is by simulating multiple processes, one process per choice
+  Then the processes are compared and if an association between a public key and a process can be made the test fails.
+  As the choice is at least as bad as choosing the worst possible option the credibility of the test is maintained.
+  The drawback is that Proverif is only able to tell if the identity can be brute forced but misses any probabilistic associations.
+  As usual Proverif also assumes perfect encryption and in particular assumes encryption cannot be linked to identity.
+
+  One of the tradeoffs made here is that the choice function in Proverif is slow but this is in favour of being able to write more precise tests.
+  Another issue is the choice function does not work with queries so a test needs to be run for each set of assumptions.
+  In this case the test uses secure rng and a fresh secure biscuit key.
+*/
+
+
+#include "config.mpv"
+
+#define CHAINING_KEY_EVENTS 1
+#define MESSAGE_TRANSMISSION_EVENTS 1
+#define SESSION_START_EVENTS 0
+#define RANDOMIZED_CALL_IDS 0
+#undef FULL_MODEL
+#undef SIMPLE_MODEL
+#define SIMPLE_MODEL 1
+
+#include "prelude/basic.mpv"
+#include "crypto/key.mpv"
+#include "rosenpass/oracles.mpv"
+#include "crypto/kem.mpv"
+
+#define INITIATOR_TEST
+#define NEW_TRUSTED_SEED(name)            \
+  new MCAT(name, _secret_seed):seed_prec; \
+  name <- make_trusted_seed(MCAT(name, _secret_seed)); \
+
+free D:channel [private].
+free secure_biscuit_no:Atom [private].
+free secure_sidi,secure_sidr:SessionId [private].
+free secure_psk:key [private].
+free initiator1, initiator2:kem_sk_prec.
+free responder1, responder2:kem_sk_prec.
+
+let secure_init_hello(initiator: kem_sk_tmpl, sidi : SessionId, psk: key_tmpl, responder: kem_sk_tmpl) =
+  NEW_TRUSTED_SEED(seski_trusted_seed)
+  NEW_TRUSTED_SEED(ssptr_trusted_seed)
+  Oinitiator_inner(sidi, initiator, psk, responder, seski_trusted_seed, ssptr_trusted_seed, D).
+
+let secure_resp_hello(initiator: kem_sk_tmpl, responder: kem_sk_tmpl, sidr:SessionId, sidi:SessionId, biscuit_no:Atom, psk:key_tmpl) =
+  in(D, Envelope(k, IH2b(InitHello(=sidi, epki, sctr, pidiC, auth))));
+  ih <- InitHello(sidi, epki, sctr, pidiC, auth);
+  NEW_TRUSTED_SEED(septi_trusted_seed)
+  NEW_TRUSTED_SEED(sspti_trusted_seed)
+  Oinit_hello_inner(sidr, biscuit_no, responder, psk, initiator, septi_trusted_seed, sspti_trusted_seed, ih, D).
+
+let secure_init_conf(initiator: kem_sk_tmpl, responder: kem_sk_tmpl, psk:key_tmpl, sidi:SessionId, sidr:SessionId) =
+  in(D, Envelope(k3, IC2b(InitConf(=sidi, =sidr, biscuit, auth3))));
+  ic <- InitConf(sidi,sidr,biscuit, auth3);
+  NEW_TRUSTED_SEED(seski_trusted_seed)
+  NEW_TRUSTED_SEED(ssptr_trusted_seed)
+  Oinit_conf_inner(initiator, psk, responder, ic).
+
+let secure_communication(initiator: kem_sk_tmpl, responder:kem_sk_tmpl) =
+  secure_key <- prepare_key(secure_psk);
+  (!secure_init_hello(initiator, secure_sidi, secure_key, responder))
+  | !secure_resp_hello(initiator, responder, secure_sidr, secure_sidi, secure_biscuit_no, secure_key)
+  | !(secure_init_conf(initiator, responder, secure_key, secure_sidi, secure_sidr)).
+
+let pipeChannel(D:channel, C:channel) =
+  in(D, b:bits);
+  out(C, b).
+
+fun kem_private(kem_pk): kem_sk
+  reduc forall sk_tmpl:kem_sk;
+    kem_private(kem_pub(sk_tmpl)) = sk_tmpl[private].
+
+let secretCommunication() =
+#ifdef INITIATOR_TEST
+  initiator_pk <- choice[setup_kem_pk(make_trusted_kem_sk(initiator1)), setup_kem_pk(make_trusted_kem_sk(initiator2))];
+  initiator_seed <- prepare_kem_sk(kem_private(initiator_pk)); 
+#else
+  initiator_seed <- prepare_kem_sk(trusted_kem_sk(initiator1));
+#endif
+#ifdef RESPONDER_TEST
+  responder_pk <- choice[setup_kem_pk(make_trusted_kem_sk(responder1)), setup_kem_pk(make_trusted_kem_sk(responder2))];
+  responder_seed <- prepare_kem_sk(kem_private(responder_pk));
+#else
+  responder_seed <- prepare_kem_sk(trusted_kem_sk(responder1));
+#endif
+  secure_communication(initiator_seed, responder_seed) | !pipeChannel(D, C).
+
+let reveal_pks() =
+  out(C, setup_kem_pk(make_trusted_kem_sk(responder1)));
+  out(C, setup_kem_pk(make_trusted_kem_sk(responder2)));
+  out(C, setup_kem_pk(make_trusted_kem_sk(initiator1)));
+  out(C, setup_kem_pk(make_trusted_kem_sk(initiator2))).
+
+let rosenpass_main2() = 
+  REP(INITIATOR_BOUND, Oinitiator)
+  | REP(RESPONDER_BOUND, Oinit_hello)
+  | REP(RESPONDER_BOUND, Oinit_conf).
+
+let identity_hiding_main() = 
+  0 | reveal_pks() |  rosenpass_main2() | phase 1; secretCommunication().
+
+let main = identity_hiding_main.

analysis/rosenpass/oracles.mpv

@@ -47,14 +47,16 @@ CK_EV(  event OskOinit_conf(key, key). )
 MTX_EV( event ICRjct(InitConf_t, key, kem_sk, kem_pk). )
 SES_EV( event ResponderSession(InitConf_t, key). )
 event ConsumeBiscuit(Atom, kem_sk, kem_pk, Atom).
-let Oinit_conf() = 
+
-  in(C, Cinit_conf(Ssskm, Spsk, Sspkt, ic));
+let Oinit_conf_inner(Ssskm:kem_sk_tmpl, Spsk:key_tmpl, Sspkt:kem_sk_tmpl, ic:InitConf_t) =
 #if RANDOMIZED_CALL_IDS
   new call:Atom;
 #else
   call <- Cinit_conf(Ssskm, Spsk, Sspkt, ic);
 #endif
+
   SETUP_HANDSHAKE_STATE()
+
   eski <- kem_sk0;
   epki <- kem_pk0;
   let try_ = (
@@ -73,6 +75,10 @@ let Oinit_conf() =
 #endif
   ).
   
+let Oinit_conf() = 
+  in(C, Cinit_conf(Ssskm, Spsk, Sspkt, ic));
+  Oinit_conf_inner(Ssskm, Spsk, Sspkt, ic).
+
 restriction biscuit_no:Atom, sskm:kem_sk, spkr:kem_pk, ad1:Atom, ad2:Atom;
   event(ConsumeBiscuit(biscuit_no, sskm, spkr, ad1)) && event(ConsumeBiscuit(biscuit_no, sskm, spkr, ad2))
     ==> ad1 = ad2.
@@ -85,8 +91,8 @@ CK_EV(  event OskOresp_hello(key, key, key). )
 MTX_EV( event RHRjct(RespHello_t, key, kem_sk, kem_pk). )
 MTX_EV( event ICSent(RespHello_t, InitConf_t, key, kem_sk, kem_pk). )
 SES_EV( event InitiatorSession(RespHello_t, key). )
-let Oresp_hello(HS_DECL_ARGS) =
+let Oresp_hello(HS_DECL_ARGS, C_in:channel) =
-  in(C, Cresp_hello(RespHello(sidr, =sidi, ecti, scti, biscuit, auth)));
+  in(C_in, Cresp_hello(RespHello(sidr, =sidi, ecti, scti, biscuit, auth)));
   rh <- RespHello(sidr, sidi, ecti, scti, biscuit, auth);
   /* try */ let ic = (
     ck_ini <- ck;
@@ -98,7 +104,7 @@ let Oresp_hello(HS_DECL_ARGS) =
     SES_EV( event InitiatorSession(rh, osk); )
     ic
   /* success */ ) in (
-    out(C, ic)
+    out(C_in, Envelope(create_mac(spkt, IC2b(ic)), IC2b(ic)))
   /* fail */ ) else (
 #if MESSAGE_TRANSMISSION_EVENTS
     event RHRjct(rh, psk, sski, spkr)
@@ -116,8 +122,8 @@ MTX_EV( event IHRjct(InitHello_t, key, kem_sk, kem_pk). )
 MTX_EV( event RHSent(InitHello_t, RespHello_t, key, kem_sk, kem_pk). )
 event ConsumeSidr(SessionId, Atom).
 event ConsumeBn(Atom, kem_sk, kem_pk, Atom).
-let Oinit_hello() = 
+
-  in(C, Cinit_hello(sidr, biscuit_no, Ssskm, Spsk, Sspkt, Septi, Sspti, ih));
+let Oinit_hello_inner(sidm:SessionId, biscuit_no:Atom, Ssskm:kem_sk_tmpl, Spsk:key_tmpl, Sspkt: kem_sk_tmpl, Septi: seed_tmpl, Sspti: seed_tmpl, ih: InitHello_t, C_out:channel) = 
 #if RANDOMIZED_CALL_IDS
   new call:Atom;
 #else
@@ -125,14 +131,19 @@ let Oinit_hello() =
 #endif
   // TODO: This is ugly
   let InitHello(sidi, epki, sctr, pidiC, auth) = ih in
+
   SETUP_HANDSHAKE_STATE()
+
   eski <- kem_sk0;
-  epti <- rng_key(setup_seed(Septi)); // RHR4
+
-  spti <- rng_key(setup_seed(Sspti)); // RHR5
   event ConsumeBn(biscuit_no, sskm, spkt, call);
   event ConsumeSidr(sidr, call);
+
+  epti <- rng_key(setup_seed(Septi)); // RHR4
+  spti <- rng_key(setup_seed(Sspti)); // RHR5
   event ConsumeSeed(Epti, setup_seed(Septi), call);
   event ConsumeSeed(Spti, setup_seed(Sspti), call);
+
   let rh = (
     INITHELLO_CONSUME()
     ck_ini <- ck;
@@ -141,7 +152,8 @@ let Oinit_hello() =
     MTX_EV( event RHSent(ih, rh, psk, sskr, spki); )
     rh
   /* success */ ) in (
-    out(C, rh)
+    out(C_out, Envelope(create_mac(spkt, RH2b(rh)), RH2b(rh)))
+
   /* fail */ ) else (
 #if MESSAGE_TRANSMISSION_EVENTS
     event IHRjct(ih, psk, sskr, spki)
@@ -150,6 +162,10 @@ let Oinit_hello() =
 #endif
   ).
 
+let Oinit_hello() = 
+  in(C, Cinit_hello(sidr, biscuit_no, Ssskm, Spsk, Sspkt, Septi, Sspti, ih));
+  Oinit_hello_inner(sidr, biscuit_no, Ssskm, Spsk, Sspkt, Septi, Sspti, ih, C).
+
 restriction sid:SessionId, ad1:Atom, ad2:Atom;
   event(ConsumeSidr(sid, ad1)) && event(ConsumeSidr(sid, ad2))
     ==> ad1 = ad2.
@@ -167,26 +183,34 @@ CK_EV( event OskOinitiator_ck(key). )
 CK_EV( event OskOinitiator(key, key, kem_sk, kem_pk, key). )
 MTX_EV( event IHSent(InitHello_t, key, kem_sk, kem_pk). )
 event ConsumeSidi(SessionId, Atom).
+
+let Oinitiator_inner(sidi: SessionId, Ssskm: kem_sk_tmpl, Spsk: key_tmpl, Sspkt: kem_sk_tmpl, Seski: seed_tmpl, Ssptr: seed_tmpl, C_out:channel) =
+  #if RANDOMIZED_CALL_IDS
+    new call:Atom;
+  #else
+    call <- Cinitiator(sidi, Ssskm, Spsk, Sspkt, Seski, Ssptr);
+  #endif
+
+    SETUP_HANDSHAKE_STATE()
+
+    sidr <- sid0;
+
+    RNG_KEM_PAIR(eski, epki, Seski) // IHI3
+    sptr <- rng_key(setup_seed(Ssptr)); // IHI5
+    event ConsumeSidi(sidi, call);
+    event ConsumeSeed(Sptr, setup_seed(Ssptr), call);
+    event ConsumeSeed(Eski, setup_seed(Seski), call);
+
+    INITHELLO_PRODUCE()
+    CK_EV( event OskOinitiator_ck(ck); ) 
+    CK_EV( event OskOinitiator(ck, psk, sski, spkr, sptr); )
+    MTX_EV( event IHSent(ih, psk, sski, spkr); )
+    out(C_out, Envelope(create_mac(spkt, IH2b(ih)), IH2b(ih)));
+    Oresp_hello(HS_PASS_ARGS, C_out).
+
 let Oinitiator() =
   in(C, Cinitiator(sidi, Ssskm, Spsk, Sspkt, Seski, Ssptr));
-#if RANDOMIZED_CALL_IDS
+  Oinitiator_inner(sidi, Ssskm, Spsk, Sspkt, Seski, Ssptr, C).
-  new call:Atom;
-#else
-  call <- Cinitiator(sidi, Ssskm, Spsk, Sspkt, Seski, Ssptr);
-#endif
-  SETUP_HANDSHAKE_STATE()
-  RNG_KEM_PAIR(eski, epki, Seski) // IHI3
-  sidr <- sid0;
-  sptr <- rng_key(setup_seed(Ssptr)); // IHI5
-  event ConsumeSidi(sidi, call);
-  event ConsumeSeed(Sptr, setup_seed(Ssptr), call);
-  event ConsumeSeed(Eski, setup_seed(Seski), call);
-  INITHELLO_PRODUCE()
-  CK_EV( event OskOinitiator_ck(ck); ) 
-  CK_EV( event OskOinitiator(ck, psk, sski, spkr, sptr); )
-  MTX_EV( event IHSent(ih, psk, sski, spkr); )
-  out(C, ih);
-  Oresp_hello(HS_PASS_ARGS).
 
 restriction sid:SessionId, ad1:Atom, ad2:Atom;
   event(ConsumeSidi(sid, ad1)) && event(ConsumeSidi(sid, ad2))

analysis/rosenpass/protocol.mpv

@@ -2,6 +2,12 @@
 #include "crypto/kem.mpv"
 #include "rosenpass/handshake_state.mpv"
 
+fun Envelope(
+  key,
+  bits
+): bits [data].
+letfun create_mac(pk:kem_pk, payload:bits) = lprf2(MAC, kem_pk2b(pk), payload).
+
 type InitHello_t.
 fun InitHello(
   SessionId, // sidi
@@ -11,6 +17,8 @@ fun InitHello(
   bits       // auth
 ) : InitHello_t [data].
 
+fun IH2b(InitHello_t) : bitstring [typeConverter].
+
 #define INITHELLO_PRODUCE()       \
   ck <- lprf1(CK_INIT, kem_pk2b(spkr)); /* IHI1 */ \
   /* not handled here */                /* IHI2 */ \
@@ -41,7 +49,9 @@ fun RespHello(
     bits       // auth
 ) : RespHello_t [data].
 
-#define RESPHELLO_PRODUCE()                   \
+fun RH2b(RespHello_t) : bitstring [typeConverter].
+
+#define RESPHELLO_PRODUCE()  \
   /* not handled here */           /* RHR1 */ \
   MIX2(sid2b(sidr), sid2b(sidi))   /* RHR3 */ \
   ENCAPS_AND_MIX(ecti, epki, epti) /* RHR4 */ \
@@ -67,6 +77,8 @@ fun InitConf(
     bits       // auth
 ) : InitConf_t [data].
 
+fun IC2b(InitConf_t) : bitstring [typeConverter].
+
 #define INITCONF_PRODUCE()                  \
   MIX2(sid2b(sidi), sid2b(sidr)) /* ICI3 */ \
   ENCRYPT_AND_MIX(auth, empty)   /* ICI4 */ \

cipher-traits/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "rosenpass-cipher-traits"
+authors = ["Karolin Varner <karo@cupdev.net>", "wucke13 <wucke13@gmail.com>"]
+version = "0.1.0"
+edition = "2021"
+license = "MIT OR Apache-2.0"
+description = "Rosenpass internal traits for cryptographic primitives"
+homepage = "https://rosenpass.eu/"
+repository = "https://github.com/rosenpass/rosenpass"
+readme = "readme.md"
+
+[dependencies]

cipher-traits/readme.md

@@ -0,0 +1,5 @@
+# Rosenpass internal libsodium bindings
+
+Rosenpass internal library providing traits for cryptographic primitives.
+
+This is an internal library; not guarantee is made about its API at this point in time.

cipher-traits/src/kem.rs

@@ -0,0 +1,47 @@
+//! Traits and implementations for Key Encapsulation Mechanisms (KEMs)
+//!
+//! KEMs are the interface provided by almost all post-quantum
+//! secure key exchange mechanisms.
+//!
+//! Conceptually KEMs are akin to public-key encryption, but instead of encrypting
+//! arbitrary data, KEMs are limited to the transmission of keys, randomly chosen during
+//!
+//! encapsulation.
+//! The [KEM] Trait describes the basic API offered by a Key Encapsulation
+//! Mechanism. Two implementations for it are provided, [StaticKEM] and [EphemeralKEM].
+
+use std::result::Result;
+
+/// Key Encapsulation Mechanism
+///
+/// The KEM interface defines three operations: Key generation, key encapsulation and key
+/// decapsulation.
+pub trait Kem {
+    type Error;
+
+    /// Secrete Key length
+    const SK_LEN: usize;
+    /// Public Key length
+    const PK_LEN: usize;
+    /// Ciphertext length
+    const CT_LEN: usize;
+    /// Shared Secret length
+    const SHK_LEN: usize;
+
+    /// Generate a keypair consisting of secret key (`sk`) and public key (`pk`)
+    ///
+    /// `keygen() -> sk, pk`
+    fn keygen(sk: &mut [u8], pk: &mut [u8]) -> Result<(), Self::Error>;
+
+    /// From a public key (`pk`), generate a shared key (`shk`, for local use)
+    /// and a cipher text (`ct`, to be sent to the owner of the `pk`).
+    ///
+    /// `encaps(pk) -> shk, ct`
+    fn encaps(shk: &mut [u8], ct: &mut [u8], pk: &[u8]) -> Result<(), Self::Error>;
+
+    /// From a secret key (`sk`) and a cipher text (`ct`) derive a shared key
+    /// (`shk`)
+    ///
+    /// `decaps(sk, ct) -> shk`
+    fn decaps(shk: &mut [u8], sk: &[u8], ct: &[u8]) -> Result<(), Self::Error>;
+}

cipher-traits/src/lib.rs

@@ -0,0 +1,2 @@
+mod kem;
+pub use kem::Kem;

ciphers/Cargo.toml

@@ -0,0 +1,22 @@
+[package]
+name = "rosenpass-ciphers"
+authors = ["Karolin Varner <karo@cupdev.net>", "wucke13 <wucke13@gmail.com>"]
+version = "0.1.0"
+edition = "2021"
+license = "MIT OR Apache-2.0"
+description = "Rosenpass internal ciphers and other cryptographic primitives used by rosenpass."
+homepage = "https://rosenpass.eu/"
+repository = "https://github.com/rosenpass/rosenpass"
+readme = "readme.md"
+
+[dependencies]
+anyhow = { workspace = true }
+rosenpass-to = { workspace = true }
+rosenpass-constant-time = { workspace = true }
+rosenpass-secret-memory = { workspace = true }
+rosenpass-oqs = { workspace = true }
+rosenpass-util = { workspace = true }
+static_assertions = { workspace = true }
+zeroize = { workspace = true }
+chacha20poly1305 = { workspace = true }
+blake2 = { workspace = true }

ciphers/readme.md

@@ -0,0 +1,5 @@
+# Rosenpass internal cryptographic primitives
+
+Ciphers and other cryptographic primitives used by rosenpass.
+
+This is an internal library; not guarantee is made about its API at this point in time.

ciphers/src/hash_domain.rs

@@ -0,0 +1,109 @@
+use anyhow::Result;
+use rosenpass_secret_memory::Secret;
+use rosenpass_to::To;
+
+use crate::subtle::incorrect_hmac_blake2b as hash;
+
+pub use hash::KEY_LEN;
+
+// TODO Use a proper Dec interface
+#[derive(Clone, Debug)]
+pub struct HashDomain([u8; KEY_LEN]);
+#[derive(Clone, Debug)]
+pub struct HashDomainNamespace([u8; KEY_LEN]);
+#[derive(Clone, Debug)]
+pub struct SecretHashDomain(Secret<KEY_LEN>);
+#[derive(Clone, Debug)]
+pub struct SecretHashDomainNamespace(Secret<KEY_LEN>);
+
+impl HashDomain {
+    pub fn zero() -> Self {
+        Self([0u8; KEY_LEN])
+    }
+
+    pub fn dup(self) -> HashDomainNamespace {
+        HashDomainNamespace(self.0)
+    }
+
+    pub fn turn_secret(self) -> SecretHashDomain {
+        SecretHashDomain(Secret::from_slice(&self.0))
+    }
+
+    // TODO: Protocol! Use domain separation to ensure that
+    pub fn mix(self, v: &[u8]) -> Result<Self> {
+        Ok(Self(hash::hash(&self.0, v).collect::<[u8; KEY_LEN]>()?))
+    }
+
+    pub fn mix_secret<const N: usize>(self, v: Secret<N>) -> Result<SecretHashDomain> {
+        SecretHashDomain::invoke_primitive(&self.0, v.secret())
+    }
+
+    pub fn into_value(self) -> [u8; KEY_LEN] {
+        self.0
+    }
+}
+
+impl HashDomainNamespace {
+    pub fn mix(&self, v: &[u8]) -> Result<HashDomain> {
+        Ok(HashDomain(
+            hash::hash(&self.0, v).collect::<[u8; KEY_LEN]>()?,
+        ))
+    }
+
+    pub fn mix_secret<const N: usize>(&self, v: Secret<N>) -> Result<SecretHashDomain> {
+        SecretHashDomain::invoke_primitive(&self.0, v.secret())
+    }
+}
+
+impl SecretHashDomain {
+    pub fn invoke_primitive(k: &[u8], d: &[u8]) -> Result<SecretHashDomain> {
+        let mut r = SecretHashDomain(Secret::zero());
+        hash::hash(k, d).to(r.0.secret_mut())?;
+        Ok(r)
+    }
+
+    pub fn zero() -> Self {
+        Self(Secret::zero())
+    }
+
+    pub fn dup(self) -> SecretHashDomainNamespace {
+        SecretHashDomainNamespace(self.0)
+    }
+
+    pub fn danger_from_secret(k: Secret<KEY_LEN>) -> Self {
+        Self(k)
+    }
+
+    pub fn mix(self, v: &[u8]) -> Result<SecretHashDomain> {
+        Self::invoke_primitive(self.0.secret(), v)
+    }
+
+    pub fn mix_secret<const N: usize>(self, v: Secret<N>) -> Result<SecretHashDomain> {
+        Self::invoke_primitive(self.0.secret(), v.secret())
+    }
+
+    pub fn into_secret(self) -> Secret<KEY_LEN> {
+        self.0
+    }
+
+    pub fn into_secret_slice(mut self, v: &[u8], dst: &[u8]) -> Result<()> {
+        hash::hash(v, dst).to(self.0.secret_mut())
+    }
+}
+
+impl SecretHashDomainNamespace {
+    pub fn mix(&self, v: &[u8]) -> Result<SecretHashDomain> {
+        SecretHashDomain::invoke_primitive(self.0.secret(), v)
+    }
+
+    pub fn mix_secret<const N: usize>(&self, v: Secret<N>) -> Result<SecretHashDomain> {
+        SecretHashDomain::invoke_primitive(self.0.secret(), v.secret())
+    }
+
+    // TODO: This entire API is not very nice; we need this for biscuits, but
+    // it might be better to extract a special "biscuit"
+    // labeled subkey and reinitialize the chain with this
+    pub fn danger_into_secret(self) -> Secret<KEY_LEN> {
+        self.0
+    }
+}

ciphers/src/lib.rs

@@ -0,0 +1,27 @@
+use static_assertions::const_assert;
+
+pub mod subtle;
+
+pub const KEY_LEN: usize = 32;
+const_assert!(KEY_LEN == aead::KEY_LEN);
+const_assert!(KEY_LEN == xaead::KEY_LEN);
+const_assert!(KEY_LEN == hash_domain::KEY_LEN);
+
+/// Authenticated encryption with associated data
+pub mod aead {
+    pub use crate::subtle::chacha20poly1305_ietf::{decrypt, encrypt, KEY_LEN, NONCE_LEN, TAG_LEN};
+}
+
+/// Authenticated encryption with associated data with a constant nonce
+pub mod xaead {
+    pub use crate::subtle::xchacha20poly1305_ietf::{
+        decrypt, encrypt, KEY_LEN, NONCE_LEN, TAG_LEN,
+    };
+}
+
+pub mod hash_domain;
+
+pub mod kem {
+    pub use rosenpass_oqs::ClassicMceliece460896 as StaticKem;
+    pub use rosenpass_oqs::Kyber512 as EphemeralKem;
+}

ciphers/src/subtle/blake2b.rs

@@ -0,0 +1,42 @@
+use zeroize::Zeroizing;
+
+use blake2::digest::crypto_common::generic_array::GenericArray;
+use blake2::digest::crypto_common::typenum::U32;
+use blake2::digest::crypto_common::KeySizeUser;
+use blake2::digest::{FixedOutput, Mac, OutputSizeUser};
+use blake2::Blake2bMac;
+
+use rosenpass_to::{ops::copy_slice, with_destination, To};
+use rosenpass_util::typenum2const;
+
+type Impl = Blake2bMac<U32>;
+
+type KeyLen = <Impl as KeySizeUser>::KeySize;
+type OutLen = <Impl as OutputSizeUser>::OutputSize;
+
+const KEY_LEN: usize = typenum2const! { KeyLen };
+const OUT_LEN: usize = typenum2const! { OutLen };
+
+pub const KEY_MIN: usize = KEY_LEN;
+pub const KEY_MAX: usize = KEY_LEN;
+pub const OUT_MIN: usize = OUT_LEN;
+pub const OUT_MAX: usize = OUT_LEN;
+
+#[inline]
+pub fn hash<'a>(key: &'a [u8], data: &'a [u8]) -> impl To<[u8], anyhow::Result<()>> + 'a {
+    with_destination(|out: &mut [u8]| {
+        let mut h = Impl::new_from_slice(key)?;
+        h.update(data);
+
+        // Jesus christ, blake2 crate, your usage of GenericArray might be nice and fancy
+        // but it introduces a ton of complexity. This cost me half an hour just to figure
+        // out the right way to use the imports while allowing for zeroization.
+        // An API based on slices might actually be simpler.
+        let mut tmp = Zeroizing::new([0u8; OUT_LEN]);
+        let mut tmp = GenericArray::from_mut_slice(tmp.as_mut());
+        h.finalize_into(&mut tmp);
+        copy_slice(tmp.as_ref()).to(out);
+
+        Ok(())
+    })
+}

ciphers/src/subtle/chacha20poly1305_ietf.rs

@@ -0,0 +1,43 @@
+use rosenpass_to::ops::copy_slice;
+use rosenpass_to::To;
+use rosenpass_util::typenum2const;
+
+use chacha20poly1305::aead::generic_array::GenericArray;
+use chacha20poly1305::ChaCha20Poly1305 as AeadImpl;
+use chacha20poly1305::{AeadCore, AeadInPlace, KeyInit, KeySizeUser};
+
+pub const KEY_LEN: usize = typenum2const! { <AeadImpl as KeySizeUser>::KeySize };
+pub const TAG_LEN: usize = typenum2const! { <AeadImpl as AeadCore>::TagSize };
+pub const NONCE_LEN: usize = typenum2const! { <AeadImpl as AeadCore>::NonceSize };
+
+#[inline]
+pub fn encrypt(
+    ciphertext: &mut [u8],
+    key: &[u8],
+    nonce: &[u8],
+    ad: &[u8],
+    plaintext: &[u8],
+) -> anyhow::Result<()> {
+    let nonce = GenericArray::from_slice(nonce);
+    let (ct, mac) = ciphertext.split_at_mut(ciphertext.len() - TAG_LEN);
+    copy_slice(plaintext).to(ct);
+    let mac_value = AeadImpl::new_from_slice(key)?.encrypt_in_place_detached(&nonce, ad, ct)?;
+    copy_slice(&mac_value[..]).to(mac);
+    Ok(())
+}
+
+#[inline]
+pub fn decrypt(
+    plaintext: &mut [u8],
+    key: &[u8],
+    nonce: &[u8],
+    ad: &[u8],
+    ciphertext: &[u8],
+) -> anyhow::Result<()> {
+    let nonce = GenericArray::from_slice(nonce);
+    let (ct, mac) = ciphertext.split_at(ciphertext.len() - TAG_LEN);
+    let tag = GenericArray::from_slice(mac);
+    copy_slice(ct).to(plaintext);
+    AeadImpl::new_from_slice(key)?.decrypt_in_place_detached(&nonce, ad, plaintext, tag)?;
+    Ok(())
+}

ciphers/src/subtle/incorrect_hmac_blake2b.rs

@@ -0,0 +1,46 @@
+use anyhow::ensure;
+use zeroize::Zeroizing;
+
+use rosenpass_constant_time::xor;
+use rosenpass_to::{ops::copy_slice, with_destination, To};
+
+use crate::subtle::blake2b;
+
+pub const KEY_LEN: usize = 32;
+pub const KEY_MIN: usize = KEY_LEN;
+pub const KEY_MAX: usize = KEY_LEN;
+pub const OUT_MIN: usize = blake2b::OUT_MIN;
+pub const OUT_MAX: usize = blake2b::OUT_MAX;
+
+/// This is a woefully incorrect implementation of hmac_blake2b.
+/// See <https://github.com/rosenpass/rosenpass/issues/68#issuecomment-1563612222>
+///
+/// It accepts 32 byte keys, exclusively.
+///
+/// This will be replaced, likely by Kekkac at some point soon.
+/// <https://github.com/rosenpass/rosenpass/pull/145>
+#[inline]
+pub fn hash<'a>(key: &'a [u8], data: &'a [u8]) -> impl To<[u8], anyhow::Result<()>> + 'a {
+    const IPAD: [u8; KEY_LEN] = [0x36u8; KEY_LEN];
+    const OPAD: [u8; KEY_LEN] = [0x5Cu8; KEY_LEN];
+
+    with_destination(|out: &mut [u8]| {
+        // Not bothering with padding; the implementation
+        // uses appropriately sized keys.
+        ensure!(key.len() == KEY_LEN);
+
+        type Key = Zeroizing<[u8; KEY_LEN]>;
+        let mut tmp_key = Key::default();
+
+        copy_slice(key).to(tmp_key.as_mut());
+        xor(&IPAD).to(tmp_key.as_mut());
+        let mut outer_data = Key::default();
+        blake2b::hash(tmp_key.as_ref(), data).to(outer_data.as_mut())?;
+
+        copy_slice(key).to(tmp_key.as_mut());
+        xor(&OPAD).to(tmp_key.as_mut());
+        blake2b::hash(tmp_key.as_ref(), outer_data.as_ref()).to(out)?;
+
+        Ok(())
+    })
+}

ciphers/src/subtle/mod.rs

@@ -0,0 +1,4 @@
+pub mod blake2b;
+pub mod chacha20poly1305_ietf;
+pub mod incorrect_hmac_blake2b;
+pub mod xchacha20poly1305_ietf;

ciphers/src/subtle/xchacha20poly1305_ietf.rs

@@ -0,0 +1,45 @@
+use rosenpass_to::ops::copy_slice;
+use rosenpass_to::To;
+use rosenpass_util::typenum2const;
+
+use chacha20poly1305::aead::generic_array::GenericArray;
+use chacha20poly1305::XChaCha20Poly1305 as AeadImpl;
+use chacha20poly1305::{AeadCore, AeadInPlace, KeyInit, KeySizeUser};
+
+pub const KEY_LEN: usize = typenum2const! { <AeadImpl as KeySizeUser>::KeySize };
+pub const TAG_LEN: usize = typenum2const! { <AeadImpl as AeadCore>::TagSize };
+pub const NONCE_LEN: usize = typenum2const! { <AeadImpl as AeadCore>::NonceSize };
+
+#[inline]
+pub fn encrypt(
+    ciphertext: &mut [u8],
+    key: &[u8],
+    nonce: &[u8],
+    ad: &[u8],
+    plaintext: &[u8],
+) -> anyhow::Result<()> {
+    let nonce = GenericArray::from_slice(nonce);
+    let (n, ct_mac) = ciphertext.split_at_mut(NONCE_LEN);
+    let (ct, mac) = ct_mac.split_at_mut(ct_mac.len() - TAG_LEN);
+    copy_slice(nonce).to(n);
+    copy_slice(plaintext).to(ct);
+    let mac_value = AeadImpl::new_from_slice(key)?.encrypt_in_place_detached(&nonce, ad, ct)?;
+    copy_slice(&mac_value[..]).to(mac);
+    Ok(())
+}
+
+#[inline]
+pub fn decrypt(
+    plaintext: &mut [u8],
+    key: &[u8],
+    ad: &[u8],
+    ciphertext: &[u8],
+) -> anyhow::Result<()> {
+    let (n, ct_mac) = ciphertext.split_at(NONCE_LEN);
+    let (ct, mac) = ct_mac.split_at(ct_mac.len() - TAG_LEN);
+    let nonce = GenericArray::from_slice(n);
+    let tag = GenericArray::from_slice(mac);
+    copy_slice(ct).to(plaintext);
+    AeadImpl::new_from_slice(key)?.decrypt_in_place_detached(&nonce, ad, plaintext, tag)?;
+    Ok(())
+}

constant-time/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "rosenpass-constant-time"
+version = "0.1.0"
+authors = ["Karolin Varner <karo@cupdev.net>", "wucke13 <wucke13@gmail.com>"]
+edition = "2021"
+license = "MIT OR Apache-2.0"
+description = "Rosenpass internal utilities for constant time crypto implementations"
+homepage = "https://rosenpass.eu/"
+repository = "https://github.com/rosenpass/rosenpass"
+readme = "readme.md"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+rosenpass-to = { workspace = true }
+memsec = { workspace = true }

constant-time/readme.md

@@ -0,0 +1,5 @@
+# Rosenpass constant time library
+
+Rosenpass internal library providing basic constant-time operations.
+
+This is an internal library; not guarantee is made about its API at this point in time.

constant-time/src/lib.rs

@@ -0,0 +1,79 @@
+use core::hint::black_box;
+
+use rosenpass_to::{with_destination, To};
+
+/// Xors the source into the destination
+///
+/// # Examples
+///
+/// ```
+/// use rosenpass_constant_time::xor;
+/// use rosenpass_to::To;
+/// assert_eq!(
+///     xor(b"world").to_this(|| b"hello".to_vec()),
+///     b"\x1f\n\x1e\x00\x0b");
+/// ```
+///
+/// # Panics
+///
+/// If source and destination are of different sizes.
+#[inline]
+pub fn xor(src: &[u8]) -> impl To<[u8], ()> + '_ {
+    with_destination(|dst: &mut [u8]| {
+        assert!(black_box(src.len()) == black_box(dst.len()));
+        for (dv, sv) in dst.iter_mut().zip(src.iter()) {
+            *black_box(dv) ^= black_box(*sv);
+        }
+    })
+}
+
+#[inline]
+pub fn memcmp(a: &[u8], b: &[u8]) -> bool {
+    a.len() == b.len()
+        && unsafe { memsec::memeq(a.as_ptr() as *const u8, b.as_ptr() as *const u8, a.len()) }
+}
+
+#[inline]
+pub fn compare(a: &[u8], b: &[u8]) -> i32 {
+    assert!(a.len() == b.len());
+    unsafe { memsec::memcmp(a.as_ptr(), b.as_ptr(), a.len()) }
+}
+
+/// Interpret the given slice as a little-endian unsigned integer
+/// and increment that integer.
+///
+/// # Examples
+///
+/// ```
+/// use rosenpass_constant_time::increment as inc;
+/// use rosenpass_to::To;
+///
+/// fn testcase(v: &[u8], correct: &[u8]) {
+///   let mut v = v.to_owned();
+///   inc(&mut v);
+///   assert_eq!(&v, correct);
+/// }
+///
+/// testcase(b"", b"");
+/// testcase(b"\x00", b"\x01");
+/// testcase(b"\x01", b"\x02");
+/// testcase(b"\xfe", b"\xff");
+/// testcase(b"\xff", b"\x00");
+/// testcase(b"\x00\x00", b"\x01\x00");
+/// testcase(b"\x01\x00", b"\x02\x00");
+/// testcase(b"\xfe\x00", b"\xff\x00");
+/// testcase(b"\xff\x00", b"\x00\x01");
+/// testcase(b"\x00\x00\x00\x00\x00\x00", b"\x01\x00\x00\x00\x00\x00");
+/// testcase(b"\x00\xa3\x00\x77\x00\x00", b"\x01\xa3\x00\x77\x00\x00");
+/// testcase(b"\xff\xa3\x00\x77\x00\x00", b"\x00\xa4\x00\x77\x00\x00");
+/// testcase(b"\xff\xff\xff\x77\x00\x00", b"\x00\x00\x00\x78\x00\x00");
+/// ```
+#[inline]
+pub fn increment(v: &mut [u8]) {
+    let mut carry = 1u8;
+    for val in v.iter_mut() {
+        let (v, c) = black_box(*val).overflowing_add(black_box(carry));
+        *black_box(val) = v;
+        *black_box(&mut carry) = black_box(black_box(c) as u8);
+    }
+}

doc/rosenpass.1

@@ -23,7 +23,7 @@ If you are not specifically tasked with developing post-quantum secure systems,
 you probably do not need this tool.
 .Ss COMMANDS
 .Bl -tag -width Ds
-.It Ar keygen private-key <file-path> public-key <file-path>
+.It Ar gen-keys --secret-key <file-path> --public-key <file-path>
 Generate a keypair to use in the exchange command later.
 Send the public-key file to your communication partner and keep the private-key
 file secret!
@@ -91,9 +91,18 @@ This makes it possible to add peers entirely from
 .Sh SEE ALSO
 .Xr rp 1 ,
 .Xr wg 1
+.Rs
+.%A Karolin Varner
+.%A Benjamin Lipp
+.%A Wanja Zaeske
+.%A Lisa Schmidt
+.%D 2023
+.%T Rosenpass
+.%U https://rosenpass.eu/whitepaper.pdf
+.Re
 .Sh STANDARDS
-This tool is the reference implementation of the Rosenpass protocol, written
+This tool is the reference implementation of the Rosenpass protocol, as
-by Karolin Varner, Benjamin Lipp, Wanja Zaeske, and Lisa Schmidt.
+specified within the whitepaper referenced above.
 .Sh AUTHORS
 Rosenpass was created by Karolin Varner, Benjamin Lipp, Wanja Zaeske,
 Marei Peischl, Stephan Ajuvo, and Lisa Schmidt.

doc/setup/multi_device_isolation.md

@@ -0,0 +1,109 @@
+# Multi Device Isolation
+
+On supported systems (just Linux, state Feb. 2024), Rosenpass uses a so-called broker architecture where multiple operating system processes work together to negotiate a key using post quantum cryptography and then send it to WireGuard to run an actual VPN. This is similar to the sandboxes used by web browsers to prevent websites accessing the rest of the computer.
+
+These processes communicate using what is called a "unix socket"; a special file that can be used by to processes to send data back and forth. There are tools to forward data from a unix socket one one host to a unix socket on another host. By using one of these tools, you can run most of Rosenpass' processes on one host while running just the process that forwards keys from Rosenpass to WireGuard on the device that establishes the WireGuard tunnel.
+
+This type of setup can provide a very high degree of isolation. When set up correctly, a critical bug in the Rosenpass code can not affect the host running WireGuard and vice versa. Keep in mind though that for this goal to be reached, the method to connect both hosts must be sufficiently secured: If the WireGuard host is allowed to perform arbitrary commands on the Rosenpass host, then an attacker with access to the WireGuard device can also take over the Rosenpass device.
+
+You can use the instructions from [Unix Domain Socket Forwarding with OpenSSH](https://www.skreutz.com/posts/unix-domain-socket-forwarding-with-openssh/) to harden the connection between the two devices after following the instructions from this tutorial.
+
+## Instructions
+
+In this manual, we are dealing with three hosts:
+
+- The **local peer**: The local host running WireGuard 
+- The **remote peer**: The remote host we are connecting to.
+- The **the rosenpass device**: The dedicated host running rosenpass. It connects with *local peer* to supply WireGuard with keys and it connects with remote peer to perform key exchanges.
+
+Lets assume, that you are starting from a working Rosenpass setup on *local peer* and *remote peer*, running rosenpass and WireGuard on each host. Both setups use configuration files. We will move the rosenpass instance running on *local peer* to the *rosenpass device* in this tutorial.
+
+### Step 0: Setup Rosenpass
+
+If you do not have a functioning rosenpass deployment on the local and remote peer at this point, you can create one by using the configuration files from the configuration-examples directory.
+
+You will need to set up the WireGuard device manually using instructions for your linux distribution. You can use the tutorial on the [arch wiki](https://wiki.archlinux.org/title/WireGuard) for reference.
+
+Make sure to set a random pre-shared key during creation of the WireGuard setup on both hosts at startup. Random pre-shared keys can be generated by using `wg genpks` on each host.
+
+For the broker based setup to work, you might have to assign the broker process the CAP_NET_ADMIN linux capability:
+
+```bash
+sudo setcap CAP_NET_ADMIN=+eip ./target/debug/rosenpass-wireguard-broker-privileged
+```
+
+Make sure the broker binaries are in your system path when starting rosenpass:
+
+```bash
+PATH="$PWD/target/debug:$PATH" ./target/debug/rosenpass exchange-config ./path/to/config/file.toml
+```
+
+You will also need to setup rosenpass on the rosenpass device.
+
+### Step 1: Verify that your rosenpass setup is working
+
+Start rosenpass on both peers using the following command.
+
+```bash
+PATH="$PWD/target/debug:$PATH" rosenpass exchange-config ./path/to/config/file.toml
+```
+
+Now you can verify that rosenpass inserted a pre-shared key on both hosts:
+
+```bash
+wg show wgRpTest preshared-keys
+```
+
+The shell output will look similar to this:
+
+```
+tdnV/wa/0Uf8Nrm3cZkKXOm4atrOEPzv1+dvaG7p7y0=    5235LJ/ONgrO8XuxECtLPzGOyWSvuzHcexzcgoHubfs=
+```
+
+The first value is the peer's public key, the second in the pre-shared key. The pre-shared keys should match.
+
+### Step 2: Manually start the broker
+
+Rosenpass starts the psk-broker internally by default. We are looking to manually start it instead.
+
+On the *local peer*, first start the broker manually:
+
+```bash
+rm -fv broker.sock; PATH="target/debug" ./target/debug/rosenpass-wireguard-broker-socket-handler --listen-path broker.sock
+```
+
+Now you should call rosenpass while make use of the created socket. Use the `psk_broker` configuration key. Your configuration will now look something like this:
+
+```bash
+PATH="$PWD/target/debug:$PATH" rosenpass --psk-broker broker.sock exchange-config ./path/to/config/file.toml
+```
+
+### Step 2: Forward the unix socket to the rosenpass device
+
+OpenSSH socket forwarding can be used; on the local peer you can execute something like the following command:
+
+```bash
+ssh -vgMR path/to/rosenpass/broker.sock:./broker.sock -L user@rosenpass_device
+```
+
+### Step 3: Start rosenpass on the rosenpass device
+
+You may need to copy your configuration files to the rosenpass device:
+
+```bash
+scp ./path/to/config/file.toml ./path/to/peer/pk ./path/to/pk ./path/to/sk user@rosenpass_device:path/to/rosenpass/
+```
+
+Now you can start rosenpass on the rosenpass device:
+
+```bash
+PATH="$PWD/target/debug:$PATH" ./target/debug/rosenpass exchange-config ./path/to/config.toml
+```
+
+### Step 4: Harden the setup
+
+This tutorial is in a very rough state; it currently provides enough hints to advanced users to convey how the setup is supposed work. For a real production setup it needs to be adapted.
+
+In particular, you can use the guide from  from [Unix Domain Socket Forwarding with OpenSSH](https://www.skreutz.com/posts/unix-domain-socket-forwarding-with-openssh/) to make sure neither the *local peer* nor the *rosenpass device* can execute arbitrary commands on each other. The socat tutorial used in this setup can be used to achieve a diversity of setups, such as forwarding the unix socket via a plain TCP socket without encryption to the rosenpass device, if a trusted network setup is used to connect the two. Other setups such as securing the connection using TLS or forwarding the connection via a serial connection can be achieved.
+
+You should also make sure that the rosenpass secret key is at no point in time stored in the *local peer*, so if you followed this tutorial you might want to regenerate the keypair on the *rosenpass device* itself.

examples/broker-in-podman-container/config/config.toml

@@ -0,0 +1,9 @@
+public_key = "./pk1"
+secret_key = "./sk1"
+listen = ["[::]:9999"]
+verbosity = "Verbose"
+
+[[peers]]
+public_key = "./pk2"
+device = "YOUR WIREGUARD DEVICE"
+peer = "YOUR PEER PK"

examples/broker-in-podman-container/rosenpass-exchange-asuser/podman-compose.yml

@@ -0,0 +1,26 @@
+version: "3.8"
+services:
+  rosenpass:
+    build: ../rosenpass/
+    command: rosenpass
+    ports:
+      - name: rosenpass-ipv4
+        target: 9999
+        host_ip: 127.0.0.1
+        published: 9999
+        protocol: udp
+        mode: host    
+      - name: rosenpass-ipv4
+        target: 9999
+        host_ip: '[::1]'
+        published: 9999
+        protocol: udp
+        mode: host    
+    environment:
+      RUST_LOG: info
+      #DEBUG_ENTRYPOINT: 1
+    cap_add:
+      - NET_ADMIN
+    volumes:
+      - ../socket:/socket:ro
+      - ../config:/config:ro

examples/broker-in-podman-container/rosenpass-psk-broker-asroot/podman-compose.yml

@@ -0,0 +1,14 @@
+version: "3.8"
+services:
+  rosenpass:
+    build: ../rosenpass
+    command: psk_broker
+    environment:
+      RUST_LOG: info
+      USER_GAINS_CAP_NET_ADMIN: 1
+      #DEBUG_ENTRYPOINT: 1
+    cap_add:
+      - NET_ADMIN
+    volumes:
+      - ../socket:/socket:rw
+    network_mode: host

examples/broker-in-podman-container/rosenpass/Dockerfile

@@ -0,0 +1,35 @@
+FROM rust:slim as build
+
+RUN apt-get update && apt-get install -y \
+  build-essential \
+  cmake \
+  libclang-dev \
+  libcap2-bin \
+  git \
+  inotify-tools
+
+RUN adduser --system --uid 768 --group rosenpass --home /var/lib/rosenpass
+
+USER rosenpass:rosenpass
+RUN cd ~rosenpass \
+  && git clone --depth 1 "https://github.com/rosenpass/rosenpass" -b dev/broker-architecture rosenpass-source \
+  && cd rosenpass-source \
+  && mkdir -p ~rosenpass/usr \
+  && cargo install --path rosenpass --root ~rosenpass/usr --bins \
+  && cargo install --path wireguard-broker --root ~rosenpass/usr --bins \
+  && cd ~rosenpass \
+  && rm -R rosenpass-source
+USER root:root
+
+# TODO: Is this proper handling of ambient capabilities?
+RUN setcap CAP_NET_ADMIN=+ep ~rosenpass/usr/bin/rosenpass-wireguard-broker-privileged
+
+VOLUME /config
+COPY ./entrypoint.sh /usr/local/sbin/docker_entrypoint
+COPY ./fd_passing.pl /usr/local/sbin/fd_passing
+RUN chmod a+x /usr/local/sbin/docker_entrypoint /usr/local/sbin/fd_passing
+ENTRYPOINT ["/usr/local/sbin/docker_entrypoint"]
+
+VOLUME /socket
+
+CMD rosenpass config.toml

examples/broker-in-podman-container/rosenpass/entrypoint.sh

@@ -0,0 +1,187 @@
+#! /bin/bash
+
+set -e # Needed by bail()
+
+log() {
+  local lvl; lvl="${1}"; shift || bail "log()" "USAGE: log LEVEL CONTEXT MSG..."
+  local ctx; ctx="${1}"; shift || bail "log()" "USAGE: log LEVEL CONTEXT MSG..."
+  echo >&2 "[entrypoint.sh/${ctx} ${lvl}]:" "$@"
+}
+
+log_debug() {
+  if [[ -n "${DEBUG_ENTRYPOINT}" ]]; then
+    log "DEBUG" "$@"
+  fi
+}
+
+log_info() {
+  log "INFO" "$@"
+}
+
+log_err() {
+  log "ERROR" "$@"
+}
+
+exc() {
+  local ctx; ctx="${1}"; shift || bail "exc()" "USAGE: exc CONTEXT CMD..."
+  log_debug '$' "$@"
+  "$@"
+}
+
+bail() {
+  local ctx; ctx="${1}"; shift || bail "bail()" "USAGE: bail CONTEXT MSG..."
+  (( "$#" != 0 )) || bail "${ctx}" $'USAGE: bail CONTEXT MSG... # Bail called without parameters! Please use error messages dear developer.'
+  log_err "${ctx}" "$@"
+  return 1
+}
+
+join() {
+  local delim; delim="$1"; shift || bail "join()" "USAGE: join DELIM ELMS..."
+  local tmp fst
+  fst="true"
+  for tmp in "$@"; do
+    if [[ "${fst}" = "true" ]]; then
+      printf "%s" "${tmp}"
+      fst=""
+    else
+      printf "%s%s" "${delim}" "${tmp}"
+    fi
+  done
+}
+
+# Shred files after they where red (recursively)
+# USAGE: $ burn_after_reading DIR
+burn_after_reading() {
+  local dir; dir="$1"; shift || bail "join()" "USAGE: burn_after_reading DIR"
+
+  log_info burn_after_reading "Started for ${dir}"
+
+  # Load the list of configuration files
+  local -a files_arr # Array
+  readarray -td $'\0' files_arr < <(find "${dir}" -type f -print0)
+
+  # Convert configuration file list to associative array
+  local file
+  local -A files_todo # Associative array
+  for file in "${files_arr[@]}"; do
+    files_todo["${file}"]="1"
+  done
+
+  # Watch for closed files
+  local file
+  # The --exclude '/$' excludes directories
+  inotifywait --quiet --monitor --event close_nowrite --exclude '/$' --recursive . --no-newline --format "%w%f%0" \
+    | while read -d $'\0' -r file; do
+
+        # Check if the file is in the todo list, if yes, erase it
+        if [[ "${files_todo["${file}"]+1}" = "1" ]]; then
+          log_info burn_after_reading "File loaded from configuration; removing now: ${file}";
+          shred "${file}"
+          # Clear from the todo list; What in the devils name is this quoting style bash
+          unset 'files_todo["${file}"]'
+        fi
+
+        # We're done if the todo list is empty
+        if (( "${#files_todo[@]}" == 0 )); then
+          return
+        fi
+      done
+}
+
+
+as_user() {
+  local -a cmd_prefix
+  if [[ "$1" = "--exec" ]]; then
+    cmd_prefix=("exec")
+    shift
+  fi
+
+  local user; user="$1"; shift || bail "as_user()" "USAGE: as_user USER CMD..."
+  (( "$#" > 0 )) || bail "as_user()" "USAGE: as_user USER CMD..."
+
+  if [[ -n "${USER_GAINS_CAP_NET_ADMIN}" ]]; then # TODO: Dirty to do this here; use --cap-net-admin or something?
+    exc "as_user()" "${cmd_prefix[@]}" \
+      capsh --caps="cap_net_admin+eip cap_setuid,cap_setgid+ep" --keep=1 \
+        --user="${user}" --addamb=cap_net_admin -- -c 'exec "$@"' -- "$@"
+  elif [[ "${user}" = "$(whoami)" ]]; then
+    exc "as_user()" "${cmd_prefix[@]}" "$@"
+  else
+    exc "as_user()" "${cmd_prefix[@]}" runuser -u "${user}" -- "$@"
+  fi
+}
+
+usage() {
+  bail "USAGE: ${SCRIPT} rosenpass|psk_broker"
+}
+
+cmd_internal() {
+  "$@"
+}
+
+cmd_run_command() {
+  exc "run_command()" as_user --exec "${SWITCH_USER}" "$@"
+}
+
+cmd_psk_broker() {
+  exc "psk_broker()" exec \
+    fd_passing --listen /socket/psk_broker.sock \
+      "$SCRIPT" internal as_user --exec "${SWITCH_USER}" \
+        rosenpass-wireguard-broker-socket-handler --listen-fd
+}
+
+rosenpass_start_with_socket_fd() {
+  local fd; fd="$1"; shift || bail "rosenpass_start_with_socket_fd()" "USAGE: rosenpass_start_with_socket_fd PSK_BROKER_FD"
+  exc "rosenpass_start_with_socket_fd()" exec \
+    rosenpass --psk-broker-fd "$fd" exchange-config /config/config.toml
+}
+
+cmd_rosenpass() {
+  test -z "${USER_GAINS_CAP_NET_ADMIN}" || bail "rosenpass()" "USER_GAINS_CAP_NET_ADMIN should be unset. The rosenpass instance doing key exchanges should not have network admin privileges!"
+  exc "psk_broker()" exec \
+    fd_passing --connect /socket/psk_broker.sock \
+      "$SCRIPT" internal as_user --exec "${SWITCH_USER}" \
+        "$SCRIPT" internal rosenpass_start_with_socket_fd
+}
+
+main() {
+  local command; command="$1"; shift || usage
+  case "${command}" in 
+    internal) cmd_internal "$@" ;;
+    run_command) ;;
+    psk_broker) ;;
+    rosenpass) ;;
+    *) usage;;
+  esac
+
+  exc "main()" umask u=rw,og=
+  exc "main()" cp -R "${CONFIG_MOUNT}" "${CONFIG_TMP}"
+  exc "main()" chmod -R u+X "${CONFIG_TMP}"
+  exc "main()" chown -R rosenpass:rosenpass "${CONFIG_TMP}"
+  # TODO: How can we do this? We should probably use a dedicated config broker.
+  #exc "main()" umount "${CONFIG_MOUNT}"
+  exc "main()" cd "${CONFIG_TMP}"
+
+  if [[ -n "${BURN_AFTER_READING}" ]]; then
+    ( burn_after_reading /dev/shm/rosenpass-config )&
+  fi
+
+  local -a path_cpy extra_path_cpy
+  mapfile -td ':' path_cpy < <(echo -n "$PATH")
+  mapfile -td ':' extra_path_cpy < <(echo -n "$EXTRA_PATH")
+  PATH="$(join ":" "${extra_path_cpy[@]}" "${path_cpy[@]}")"
+  export PATH
+
+  exc "main()" "cmd_${command}" "$@"
+}
+
+SCRIPT="$0"
+
+# Config
+CONFIG_MOUNT="${CONFIG_MOUNT:-/config}"
+CONFIG_TMP="${CONFIG_TMP:-/dev/shm/rosenpass-config}"
+BURN_AFTER_READING="${BURN_AFTER_READING:-true}"
+SWITCH_USER="${SWITCH_USER:-rosenpass}"
+#USER_GAINS_CAP_NET_ADMIN="${USER_GAINS_CAP_NET_ADMIN}"
+EXTRA_PATH="${EXTRA_PATH:-"$(eval echo ~rosenpass)/usr/bin"}"
+
+main "$@"

examples/broker-in-podman-container/rosenpass/fd_passing.pl

@@ -0,0 +1,38 @@
+#! /usr/bin/perl
+
+use Fcntl;
+use IO::Socket::UNIX;
+
+my $usage = "[$0] Usage: $0 SOCKETPATH [--connect|--listen] CMD...";
+
+my $mode = shift or die($usage);
+my $sopath = shift or die($usage);
+
+
+my $listen;
+if ($mode eq "--listen") {
+  $listen = 1;
+} elsif ($mode eq "--connect") {
+  $listen = 0;
+} else {
+  die($usage);
+}
+
+my $socket;
+if ($listen == 1) {
+  $socket = IO::Socket::UNIX->new(
+      Type => SOCK_STREAM(),
+      Local => $sopath,
+      Listen => 1,
+  ) or die "[$0] Error listening on socket socket: $!";
+} else {
+  $socket = IO::Socket::UNIX->new(
+      Type => SOCK_STREAM(),
+      Peer => $sopath,
+  ) or die "[$0] Error listening on socket socket: $!";
+}
+
+my $fd_flags = $socket->fcntl(F_GETFD, 0) or die "[$0] fcntl F_GETFD: $!";
+$socket->fcntl(F_SETFD, $fd_flags & ~FD_CLOEXEC) or die "[$0] fcntl F_SETFD: $!";
+
+exec(@ARGV, $socket->fileno);  # pass it on the command line

flake.nix

@@ -29,6 +29,7 @@
       ]
         (system:
           let
+            scoped = (scope: scope.result);
             lib = nixpkgs.lib;
 
             # normal nixpkgs
@@ -58,11 +59,35 @@
             cargoToml = builtins.fromTOML (builtins.readFile ./rosenpass/Cargo.toml);
 
             # source files relevant for rust
-            src = pkgs.lib.sources.sourceFilesBySuffices ./. [
+            src = scoped rec {
-              ".lock"
+              # File suffices to include
-              ".rs"
+              extensions = [
-              ".toml"
+                "lock"
-            ];
+                "rs"
+                "toml"
+              ];
+              # Files to explicitly include
+              files = [
+                "to/README.md"
+              ];
+
+              src = ./.;
+              filter = (path: type: scoped rec {
+                inherit (lib) any id removePrefix hasSuffix;
+                anyof = (any id);
+
+                basename = baseNameOf (toString path);
+                relative = removePrefix (toString src + "/") (toString path);
+
+                result = anyof [
+                  (type == "directory")
+                  (any (ext: hasSuffix ".${ext}" basename) extensions)
+                  (any (file: file == relative) files)
+                ];
+              });
+
+              result = pkgs.lib.sources.cleanSourceWith { inherit src filter; };
+            };
 
             # builds a bin path for all dependencies for the `rp` shellscript
             rpBinPath = p: with p; lib.makeBinPath [
@@ -266,7 +291,6 @@
               ];
               buildPhase = ''
                 export HOME=$(mktemp -d)
-                export OSFONTDIR="$(kpsewhich --var-value TEXMF)/fonts/{opentype/public/nunito,truetype/google/noto}"
                 latexmk -r tex/CI.rc
               '';
               installPhase = ''
@@ -325,7 +349,7 @@
           checks = {
             cargo-fmt = pkgs.runCommand "check-cargo-fmt"
               { inherit (self.devShells.${system}.default) nativeBuildInputs buildInputs; } ''
-              cargo fmt --manifest-path=${./.}/Cargo.toml --check && touch $out
+              cargo fmt --manifest-path=${./.}/Cargo.toml --check --all && touch $out
             '';
             nixpkgs-fmt = pkgs.runCommand "check-nixpkgs-fmt"
               { nativeBuildInputs = [ pkgs.nixpkgs-fmt ]; } ''

format_rust_code.sh

@@ -0,0 +1,115 @@
+#!/usr/bin/env bash
+
+# Parse command line options
+while [[ $# -gt 0 ]]; do
+    case "$1" in
+        --mode)
+            mode="$2"
+            shift 2
+            ;;
+        *)
+            echo "Unknown option: $1"
+            exit 1
+            ;;
+    esac
+done
+
+# Check if mode is specified
+if [ -z "$mode" ]; then
+    echo "Please specify the mode using --mode option. Valid modes are 'check' and 'fix'."
+    exit 1
+fi
+
+# Find all Markdown files in the current directory and its subdirectories
+mapfile -t md_files < <(find . -type f -name "*.md")
+
+count=0
+# Iterate through each Markdown file
+for file in "${md_files[@]}"; do
+    # Use awk to extract Rust code blocks enclosed within triple backticks
+    rust_code_blocks=$(awk '/```rust/{flag=1; next}/```/{flag=0} flag' "$file")
+
+    # Count the number of Rust code blocks
+    num_fences=$(awk '/```rust/{f=1} f{if(/```/){f=0; count++}} END{print count}' "$file")
+
+    if [ -n "$rust_code_blocks" ]; then
+        echo "Processing Rust code in $file"
+        # Iterate through each Rust code block
+        for ((i=1; i <= num_fences ; i++)); do
+            # Extract individual Rust code block using awk
+            current_rust_block=$(awk -v i="$i" '/```rust/{f=1; if (++count == i) next} f&&/```/{f=0;next} f' "$file")
+            # Variable to check if we have added the main function
+            add_main=0  
+            # Check if the Rust code block is already inside a function
+            if ! echo "$current_rust_block" | grep -q "fn main()"; then
+                # If not, wrap it in a main function
+                current_rust_block=$'fn main() {\n'"$current_rust_block"$'\n}'
+                add_main=1
+            fi
+            if [ "$mode" == "check" ]; then
+                # Apply changes to the Rust code block
+                formatted_rust_code=$(echo "$current_rust_block" | rustfmt)
+                # Use rustfmt to format the Rust code block, remove first and last lines, and remove the first 4 spaces if added  main function
+                if [ "$add_main" == 1 ]; then
+                    formatted_rust_code=$(echo "$formatted_rust_code" | sed '1d;$d' | sed 's/^    //')
+                    current_rust_block=$(echo "$current_rust_block" | sed '1d;')
+                    current_rust_block=$(echo "$current_rust_block" | sed '$d')
+                fi
+                if [ "$formatted_rust_code" == "$current_rust_block" ]; then
+                    echo "No changes needed in Rust code block $i in $file"
+                else
+                    echo -e "\nChanges needed in Rust code block $i in $file:\n"
+                    echo "$formatted_rust_code"
+                    count=+1
+                fi
+
+            elif [ "$mode" == "fix" ]; then
+                # Replace current_rust_block with formatted_rust_code in the file
+                formatted_rust_code=$(echo "$current_rust_block" | rustfmt)
+                # Use rustfmt to format the Rust code block, remove first and last lines, and remove the first 4 spaces if added  main function
+                if [ "$add_main" == 1 ]; then
+                    formatted_rust_code=$(echo "$formatted_rust_code" | sed '1d;$d' | sed 's/^    //')
+                    current_rust_block=$(echo "$current_rust_block" | sed '1d;')
+                    current_rust_block=$(echo "$current_rust_block" | sed '$d')
+                fi
+                # Check if the formatted code is the same as the current Rust code block
+                if [ "$formatted_rust_code" == "$current_rust_block" ]; then
+                    echo "No changes needed in Rust code block $i in $file"
+                else
+                    echo "Formatting Rust code block $i in $file"
+                    # Replace current_rust_block with formatted_rust_code in the file
+                    # Use awk to find the line number of the pattern
+
+                    start_line=$(grep -n "^\`\`\`rust" "$file" | sed -n "${i}p" | cut -d: -f1)
+                    end_line=$(grep -n "^\`\`\`" "$file" | awk -F: -v start_line="$start_line" '$1 > start_line {print $1; exit;}')
+
+                    if [ -n "$start_line" ] && [ -n "$end_line" ]; then
+                        # Print lines before the Rust code block
+                        head -n "$((start_line - 1))" "$file"
+
+                        # Print the formatted Rust code block
+                        echo "\`\`\`rust"
+                        echo "$formatted_rust_code"
+                        echo "\`\`\`"
+
+                        # Print lines after the Rust code block
+                        tail -n +"$((end_line + 1))" "$file"
+                    else
+                        # Rust code block not found or end line not found
+                        cat "$file"
+                    fi > tmpfile && mv tmpfile "$file"
+
+                fi
+            else  
+                echo "Unknown mode: $mode. Valid modes are 'check' and 'fix'."
+                exit 1
+            fi
+        done
+    fi
+done
+
+# CI failure if changes are needed
+if [ $count -gt 0 ]; then
+    echo "CI failed: Changes needed in Rust code blocks."
+    exit 1
+fi

fuzz/.gitignore

@@ -0,0 +1,4 @@
+target
+corpus
+artifacts
+coverage

fuzz/Cargo.toml

@@ -0,0 +1,60 @@
+[package]
+name = "rosenpass-fuzzing"
+version = "0.0.1"
+publish = false
+edition = "2021"
+
+[package.metadata]
+cargo-fuzz = true
+
+[dependencies]
+arbitrary = { workspace = true }
+libfuzzer-sys = { workspace = true }
+stacker = { workspace = true }
+rosenpass-secret-memory = { workspace = true }
+rosenpass-ciphers = { workspace = true }
+rosenpass-cipher-traits = { workspace = true }
+rosenpass-to = { workspace = true }
+rosenpass = { workspace = true }
+
+[[bin]]
+name = "fuzz_handle_msg"
+path = "fuzz_targets/handle_msg.rs"
+test = false
+doc = false
+
+[[bin]]
+name = "fuzz_blake2b"
+path = "fuzz_targets/blake2b.rs"
+test = false
+doc = false
+
+[[bin]]
+name = "fuzz_aead_enc_into"
+path = "fuzz_targets/aead_enc_into.rs"
+test = false
+doc = false
+
+[[bin]]
+name = "fuzz_mceliece_encaps"
+path = "fuzz_targets/mceliece_encaps.rs"
+test = false
+doc = false
+
+[[bin]]
+name = "fuzz_kyber_encaps"
+path = "fuzz_targets/kyber_encaps.rs"
+test = false
+doc = false
+
+[[bin]]
+name = "fuzz_box_secret_alloc"
+path = "fuzz_targets/box_secret_alloc.rs"
+test = false
+doc = false
+
+[[bin]]
+name = "fuzz_vec_secret_alloc"
+path = "fuzz_targets/vec_secret_alloc.rs"
+test = false
+doc = false

fuzz/fuzz_targets/aead_enc_into.rs

@@ -0,0 +1,29 @@
+#![no_main]
+extern crate arbitrary;
+extern crate rosenpass;
+
+use libfuzzer_sys::fuzz_target;
+
+use rosenpass_ciphers::aead;
+
+#[derive(arbitrary::Arbitrary, Debug)]
+pub struct Input {
+    pub key: [u8; 32],
+    pub nonce: [u8; 12],
+    pub ad: Box<[u8]>,
+    pub plaintext: Box<[u8]>,
+}
+
+fuzz_target!(|input: Input| {
+    let mut ciphertext: Vec<u8> = Vec::with_capacity(input.plaintext.len() + 16);
+    ciphertext.resize(input.plaintext.len() + 16, 0);
+
+    aead::encrypt(
+        ciphertext.as_mut_slice(),
+        &input.key,
+        &input.nonce,
+        &input.ad,
+        &input.plaintext,
+    )
+    .unwrap();
+});

fuzz/fuzz_targets/blake2b.rs

@@ -0,0 +1,20 @@
+#![no_main]
+extern crate arbitrary;
+extern crate rosenpass;
+
+use libfuzzer_sys::fuzz_target;
+
+use rosenpass_ciphers::subtle::blake2b;
+use rosenpass_to::To;
+
+#[derive(arbitrary::Arbitrary, Debug)]
+pub struct Blake2b {
+    pub key: [u8; 32],
+    pub data: Box<[u8]>,
+}
+
+fuzz_target!(|input: Blake2b| {
+    let mut out = [0u8; 32];
+
+    blake2b::hash(&input.key, &input.data).to(&mut out).unwrap();
+});

fuzz/fuzz_targets/box_secret_alloc.rs

@@ -0,0 +1,8 @@
+#![no_main]
+
+use libfuzzer_sys::fuzz_target;
+use rosenpass_secret_memory::alloc::secret_box;
+
+fuzz_target!(|data: &[u8]| {
+    let _ = secret_box(data);
+});

fuzz/fuzz_targets/handle_msg.rs

@@ -0,0 +1,18 @@
+#![no_main]
+extern crate rosenpass;
+
+use libfuzzer_sys::fuzz_target;
+
+use rosenpass::protocol::CryptoServer;
+use rosenpass_secret_memory::Secret;
+
+fuzz_target!(|rx_buf: &[u8]| {
+    let sk = Secret::from_slice(&[0; 13568]);
+    let pk = Secret::from_slice(&[0; 524160]);
+
+    let mut cs = CryptoServer::new(sk, pk);
+    let mut tx_buf = [0; 10240];
+
+    // We expect errors while fuzzing therefore we do not check the result.
+    let _ = cs.handle_msg(rx_buf, &mut tx_buf);
+});

fuzz/fuzz_targets/kyber_encaps.rs

@@ -0,0 +1,20 @@
+#![no_main]
+extern crate arbitrary;
+extern crate rosenpass;
+
+use libfuzzer_sys::fuzz_target;
+
+use rosenpass_cipher_traits::Kem;
+use rosenpass_ciphers::kem::EphemeralKem;
+
+#[derive(arbitrary::Arbitrary, Debug)]
+pub struct Input {
+    pub pk: [u8; 800],
+}
+
+fuzz_target!(|input: Input| {
+    let mut ciphertext = [0u8; 768];
+    let mut shared_secret = [0u8; 32];
+
+    EphemeralKem::encaps(&mut shared_secret, &mut ciphertext, &input.pk).unwrap();
+});

fuzz/fuzz_targets/mceliece_encaps.rs

@@ -0,0 +1,15 @@
+#![no_main]
+extern crate rosenpass;
+
+use libfuzzer_sys::fuzz_target;
+
+use rosenpass_cipher_traits::Kem;
+use rosenpass_ciphers::kem::StaticKem;
+
+fuzz_target!(|input: [u8; StaticKem::PK_LEN]| {
+    let mut ciphertext = [0u8; 188];
+    let mut shared_secret = [0u8; 32];
+
+    // We expect errors while fuzzing therefore we do not check the result.
+    let _ = StaticKem::encaps(&mut shared_secret, &mut ciphertext, &input);
+});

fuzz/fuzz_targets/vec_secret_alloc.rs

@@ -0,0 +1,9 @@
+#![no_main]
+
+use libfuzzer_sys::fuzz_target;
+use rosenpass_secret_memory::alloc::secret_vec;
+
+fuzz_target!(|data: &[u8]| {
+    let mut vec = secret_vec();
+    vec.extend_from_slice(data);
+});

lenses/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "rosenpass-lenses"
+version = "0.1.0"
+authors = ["Karolin Varner <karo@cupdev.net>", "wucke13 <wucke13@gmail.com>"]
+edition = "2021"
+license = "MIT OR Apache-2.0"
+description = "Rosenpass internal library for parsing binary data securely"
+homepage = "https://rosenpass.eu/"
+repository = "https://github.com/rosenpass/rosenpass"
+readme = "readme.md"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+paste = { workspace = true }
+thiserror = { workspace = true }

lenses/readme.md

@@ -0,0 +1,3 @@
+# Rosenpass internal binary parsing library
+
+This is an internal library; no guarantee is made about its API at this point in time.

lenses/src/lib.rs

@@ -0,0 +1,206 @@
+use std::result::Result;
+
+/// Common trait shared by all Lenses
+pub trait LenseView {
+    const LEN: usize;
+}
+
+/// Error during lense creation
+#[derive(thiserror::Error, Debug, Eq, PartialEq, Clone)]
+pub enum LenseError {
+    #[error("buffer size mismatch")]
+    BufferSizeMismatch,
+}
+
+pub type LenseResult<T> = Result<T, LenseError>;
+
+impl LenseError {
+    pub fn ensure_exact_buffer_size(len: usize, required: usize) -> LenseResult<()> {
+        (len == required)
+            .then_some(())
+            .ok_or(LenseError::BufferSizeMismatch)
+    }
+
+    pub fn ensure_sufficient_buffer_size(len: usize, required: usize) -> LenseResult<()> {
+        (len >= required)
+            .then_some(())
+            .ok_or(LenseError::BufferSizeMismatch)
+    }
+}
+
+/// A macro to create data lenses.
+#[macro_export]
+macro_rules! lense(
+    // prefix          @ offset       ; optional meta    ; field name   : field length, ...
+    (token_muncher_ref @ $offset:expr ; $( $attr:meta )* ; $field:ident : $len:expr $(, $( $tail:tt )+ )?) =>  {
+        ::paste::paste!{
+
+        #[allow(rustdoc::broken_intra_doc_links)]
+        $( #[ $attr ] )*
+        ///
+        #[doc = lense!(maybe_docstring_link $len)]
+        /// bytes long
+        pub fn $field(&self) -> &__ContainerType::Output {
+            &self.0[$offset .. $offset + $len]
+        }
+
+        /// The bytes until the
+        #[doc = lense!(maybe_docstring_link Self::$field)]
+        /// field
+        pub fn [< until_ $field >](&self) -> &__ContainerType::Output {
+            &self.0[0 .. $offset]
+        }
+
+        // if the tail exits, consume it as well
+        $(
+        lense!{token_muncher_ref @ $offset + $len ; $( $tail )+ }
+        )?
+        }
+    };
+
+    // prefix          @ offset       ; optional meta    ; field name   : field length, ...
+    (token_muncher_mut @ $offset:expr ; $( $attr:meta )* ; $field:ident : $len:expr $(, $( $tail:tt )+ )?) =>  {
+        ::paste::paste!{
+
+        #[allow(rustdoc::broken_intra_doc_links)]
+        $( #[ $attr ] )*
+        ///
+        #[doc = lense!(maybe_docstring_link $len)]
+        /// bytes long
+        pub fn [< $field _mut >](&mut self) -> &mut __ContainerType::Output {
+            &mut self.0[$offset .. $offset + $len]
+        }
+
+        // if the tail exits, consume it as well
+        $(
+        lense!{token_muncher_mut @ $offset + $len ; $( $tail )+ }
+        )?
+        }
+    };
+
+    // switch that yields literals unchanged, but creates docstring links to
+    // constants
+    // TODO the doc string link doesn't work if $x is taken from a generic,
+    (maybe_docstring_link $x:literal) => (stringify!($x));
+    (maybe_docstring_link $x:expr) => (stringify!([$x]));
+
+    // struct name  < optional generics     >    := optional doc string      field name   : field length, ...
+($type:ident $( < $( $generic:ident ),+ > )? := $( $( #[ $attr:meta ] )* $field:ident : $len:expr ),+) => (::paste::paste!{
+
+        #[allow(rustdoc::broken_intra_doc_links)]
+        /// A data lense to manipulate byte slices.
+        ///
+        //// # Fields
+        ///
+        $(
+        /// - `
+        #[doc = stringify!($field)]
+        /// `:
+        #[doc = lense!(maybe_docstring_link $len)]
+        /// bytes
+        )+
+        pub struct $type<__ContainerType $(, $( $generic ),+ )? > (
+            __ContainerType,
+            // The phantom data is required, since all generics declared on a
+            // type need to be used on the type.
+            // https://doc.rust-lang.org/stable/error_codes/E0392.html
+            $( $( ::core::marker::PhantomData<$generic> ),+ )?
+        );
+
+        impl<__ContainerType $(, $( $generic: LenseView ),+ )? > $type<__ContainerType $(, $( $generic ),+ )? >{
+            $(
+            /// Size in bytes of the field `
+            #[doc = !($field)]
+            /// `
+            pub const fn [< $field _len >]() -> usize{
+                $len
+            }
+            )+
+
+            /// Verify that `len` exactly holds [Self]
+            pub fn check_size(len: usize) -> ::rosenpass_lenses::LenseResult<()> {
+                ::rosenpass_lenses::LenseError::ensure_exact_buffer_size(len, $( $len + )+ 0)
+            }
+        }
+
+        // read-only accessor functions
+        impl<'a, __ContainerType $(, $( $generic: LenseView ),+ )?> $type<&'a __ContainerType $(, $( $generic ),+ )?>
+        where
+            __ContainerType: std::ops::Index<std::ops::Range<usize>> + ?Sized,
+        {
+            lense!{token_muncher_ref @ 0 ; $( $( $attr )* ; $field : $len ),+ }
+
+            /// View into all bytes belonging to this Lense
+            pub fn all_bytes(&self) -> &__ContainerType::Output {
+                &self.0[0..Self::LEN]
+            }
+        }
+
+        // mutable accessor functions
+        impl<'a, __ContainerType $(, $( $generic: LenseView ),+ )?> $type<&'a mut __ContainerType $(, $( $generic ),+ )?>
+        where
+            __ContainerType: std::ops::IndexMut<std::ops::Range<usize>> + ?Sized,
+        {
+            lense!{token_muncher_ref @ 0 ; $( $( $attr )* ; $field : $len ),+ }
+            lense!{token_muncher_mut @ 0 ; $( $( $attr )* ; $field : $len ),+ }
+
+            /// View into all bytes belonging to this Lense
+            pub fn all_bytes(&self) -> &__ContainerType::Output {
+                &self.0[0..Self::LEN]
+            }
+
+            /// View into all bytes belonging to this Lense
+            pub fn all_bytes_mut(&mut self) -> &mut __ContainerType::Output {
+                &mut self.0[0..Self::LEN]
+            }
+        }
+
+        // lense trait, allowing us to know the implementing lenses size
+        impl<__ContainerType $(, $( $generic: LenseView ),+ )? > LenseView for $type<__ContainerType $(, $( $generic ),+ )? >{
+            /// Number of bytes required to store this type in binary format
+            const LEN: usize = $( $len + )+ 0;
+        }
+
+        /// Extension trait to allow checked creation of a lense over
+        /// some byte slice that contains a
+        #[doc = lense!(maybe_docstring_link $type)]
+        pub trait [< $type Ext >] {
+            type __ContainerType;
+
+            /// Create a lense to the byte slice
+            fn [< $type:snake >] $(< $($generic : LenseView),* >)? (self) -> ::rosenpass_lenses::LenseResult< $type<Self::__ContainerType, $( $($generic),+ )? >>;
+
+            /// Create a lense to the byte slice, automatically truncating oversized buffers
+            fn [< $type:snake _ truncating >] $(< $($generic : LenseView),* >)? (self) -> ::rosenpass_lenses::LenseResult< $type<Self::__ContainerType, $( $($generic),+ )? >>;
+        }
+
+        impl<'a> [< $type Ext >] for &'a [u8] {
+            type __ContainerType = &'a [u8];
+
+            fn [< $type:snake >] $(< $($generic : LenseView),* >)? (self) -> ::rosenpass_lenses::LenseResult< $type<Self::__ContainerType, $( $($generic),+ )? >> {
+                $type::<Self::__ContainerType, $( $($generic),+ )? >::check_size(self.len())?;
+                Ok($type ( self, $( $( ::core::marker::PhantomData::<$generic>  ),+ )? ))
+            }
+
+            fn [< $type:snake _ truncating >] $(< $($generic : LenseView),* >)? (self) -> ::rosenpass_lenses::LenseResult< $type<Self::__ContainerType, $( $($generic),+ )? >> {
+                let required_size = $( $len + )+ 0;
+                ::rosenpass_lenses::LenseError::ensure_sufficient_buffer_size(self.len(), required_size)?;
+                [< $type Ext >]::[< $type:snake >](&self[..required_size])
+            }
+        }
+
+        impl<'a> [< $type Ext >] for &'a mut [u8] {
+            type __ContainerType = &'a mut [u8];
+            fn [< $type:snake >] $(< $($generic : LenseView),* >)? (self) -> ::rosenpass_lenses::LenseResult< $type<Self::__ContainerType, $( $($generic),+ )? >> {
+                $type::<Self::__ContainerType, $( $($generic),+ )? >::check_size(self.len())?;
+                Ok($type ( self, $( $( ::core::marker::PhantomData::<$generic>  ),+ )? ))
+            }
+
+            fn [< $type:snake _ truncating >] $(< $($generic : LenseView),* >)? (self) -> ::rosenpass_lenses::LenseResult< $type<Self::__ContainerType, $( $($generic),+ )? >> {
+                let required_size = $( $len + )+ 0;
+                ::rosenpass_lenses::LenseError::ensure_sufficient_buffer_size(self.len(), required_size)?;
+                [< $type Ext >]::[< $type:snake >](&mut self[..required_size])
+            }
+        }
+    });
+);

oqs/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "rosenpass-oqs"
+authors = ["Karolin Varner <karo@cupdev.net>", "wucke13 <wucke13@gmail.com>"]
+version = "0.1.0"
+edition = "2021"
+license = "MIT OR Apache-2.0"
+description = "Rosenpass internal bindings to liboqs"
+homepage = "https://rosenpass.eu/"
+repository = "https://github.com/rosenpass/rosenpass"
+readme = "readme.md"
+
+[dependencies]
+rosenpass-cipher-traits = { workspace = true }
+rosenpass-util = { workspace = true }
+oqs-sys = { workspace = true }
+paste = { workspace = true }

oqs/readme.md

@@ -0,0 +1,5 @@
+# Rosenpass internal liboqs bindings
+
+Rosenpass internal library providing bindings to liboqs.
+
+This is an internal library; not guarantee is made about its API at this point in time.

oqs/src/kem_macro.rs

@@ -0,0 +1,80 @@
+macro_rules! oqs_kem {
+    ($name:ident) => { ::paste::paste!{
+        mod [< $name:snake >] {
+            use rosenpass_cipher_traits::Kem;
+            use rosenpass_util::result::Guaranteed;
+
+            pub enum [< $name:camel >]  {}
+
+            /// # Panic & Safety
+            ///
+            /// This Trait impl calls unsafe [oqs_sys] functions, that write to byte
+            /// slices only identified using raw pointers. It must be ensured that the raw
+            /// pointers point into byte slices of sufficient length, to avoid UB through
+            /// overwriting of arbitrary data. This is ensured through assertions in the
+            /// implementation.
+            ///
+            /// __Note__: This requirement is stricter than necessary, it would suffice
+            /// to only check that the buffers are big enough, allowing them to be even
+            /// bigger. However, from a correctness point of view it does not make sense to
+            /// allow bigger buffers.
+            impl Kem for [< $name:camel >] {
+                type Error = ::std::convert::Infallible;
+
+                const SK_LEN: usize =  ::oqs_sys::kem::[<OQS_KEM _ $name:snake _ length_secret_key >] as usize;
+                const PK_LEN: usize =  ::oqs_sys::kem::[<OQS_KEM _ $name:snake _ length_public_key >] as usize;
+                const CT_LEN: usize =  ::oqs_sys::kem::[<OQS_KEM _ $name:snake _ length_ciphertext >] as usize;
+                const SHK_LEN: usize =  ::oqs_sys::kem::[<OQS_KEM _ $name:snake _ length_shared_secret >] as usize;
+
+                fn keygen(sk: &mut [u8], pk: &mut [u8]) -> Guaranteed<()> {
+                    assert_eq!(sk.len(), Self::SK_LEN);
+                    assert_eq!(pk.len(), Self::PK_LEN);
+                    unsafe {
+                        oqs_call!(
+                            ::oqs_sys::kem::[< OQS_KEM _ $name:snake _ keypair >],
+                            pk.as_mut_ptr(),
+                            sk.as_mut_ptr()
+                        );
+                    }
+
+                    Ok(())
+                }
+
+                fn encaps(shk: &mut [u8], ct: &mut [u8], pk: &[u8]) -> Guaranteed<()> {
+                    assert_eq!(shk.len(), Self::SHK_LEN);
+                    assert_eq!(ct.len(), Self::CT_LEN);
+                    assert_eq!(pk.len(), Self::PK_LEN);
+                    unsafe {
+                        oqs_call!(
+                            ::oqs_sys::kem::[< OQS_KEM _ $name:snake _ encaps >],
+                            ct.as_mut_ptr(),
+                            shk.as_mut_ptr(),
+                            pk.as_ptr()
+                        );
+                    }
+
+                    Ok(())
+                }
+
+                fn decaps(shk: &mut [u8], sk: &[u8], ct: &[u8]) -> Guaranteed<()> {
+                    assert_eq!(shk.len(), Self::SHK_LEN);
+                    assert_eq!(sk.len(), Self::SK_LEN);
+                    assert_eq!(ct.len(), Self::CT_LEN);
+                    unsafe {
+                        oqs_call!(
+                            ::oqs_sys::kem::[< OQS_KEM _ $name:snake _ decaps >],
+                            shk.as_mut_ptr(),
+                            ct.as_ptr(),
+                            sk.as_ptr()
+                        );
+                    }
+
+                    Ok(())
+                }
+            }
+
+        }
+
+        pub use [< $name:snake >] :: [< $name:camel >];
+    }}
+}

oqs/src/lib.rs

@@ -0,0 +1,21 @@
+macro_rules! oqs_call {
+    ($name:path, $($args:expr),*) => {{
+        use oqs_sys::common::OQS_STATUS::*;
+
+        match $name($($args),*) {
+            OQS_SUCCESS => {}, // nop
+            OQS_EXTERNAL_LIB_ERROR_OPENSSL => {
+                panic!("OpenSSL error in liboqs' {}.", stringify!($name));
+            },
+            OQS_ERROR => {
+                panic!("Unknown error in liboqs' {}.", stringify!($name));
+            }
+        }
+    }};
+    ($name:ident) => { oqs_call!($name, ) };
+}
+
+#[macro_use]
+mod kem_macro;
+oqs_kem!(kyber_512);
+oqs_kem!(classic_mceliece_460896);

papers/tex/template-rosenpass.tex

@@ -177,7 +177,11 @@ version={4.0},
 		\titlehead{\centerline{\includegraphics[width=4cm]{RosenPass-Logo}}}
 		\title{\inserttitle}
 	}
-	\author{\csname insertauthor\endcsname}
+	\ifx\csname insertauthor\endcsname\relax
+	\author{}
+	\else
+	\author{\parbox{\linewidth}{\centering\insertauthor}}
+	\fi
 	\subject{\csname insertsubject\endcsname}
 	\date{\vspace{-1cm}}
 }

rosenpass/Cargo.toml

@@ -1,10 +1,10 @@
 [package]
 name = "rosenpass"
-version = "0.2.2"
+description = "Build post-quantum-secure VPNs with WireGuard!"
+version = "0.2.1"
 authors = ["Karolin Varner <karo@cupdev.net>", "wucke13 <wucke13@gmail.com>"]
 edition = "2021"
 license = "MIT OR Apache-2.0"
-description = "Build post-quantum-secure VPNs with WireGuard!"
 homepage = "https://rosenpass.eu/"
 repository = "https://github.com/rosenpass/rosenpass"
 readme = "readme.md"
@@ -14,29 +14,33 @@ name = "handshake"
 harness = false
 
 [dependencies]
-anyhow = { version = "1.0.71", features = ["backtrace"] }
+rosenpass-util = { workspace = true }
-base64 = "0.21.1"
+rosenpass-constant-time = { workspace = true }
-static_assertions = "1.1.0"
+rosenpass-ciphers = { workspace = true }
-memoffset = "0.9.0"
+rosenpass-cipher-traits = { workspace = true }
-libsodium-sys-stable = { version = "1.19.28", features = ["use-pkg-config"] }
+rosenpass-to = { workspace = true }
-oqs-sys = { version = "0.8", default-features = false, features = ['classic_mceliece', 'kyber'] }
+rosenpass-secret-memory = { workspace = true }
-lazy_static = "1.4.0"
+rosenpass-lenses = { workspace = true }
-thiserror = "1.0.40"
+rosenpass-wireguard-broker = { workspace = true }
-paste = "1.0.12"
+anyhow = { workspace = true }
-log = { version = "0.4.17", optional = true }
+static_assertions = { workspace = true }
-env_logger = { version = "0.10.0", optional = true }
+memoffset = { workspace = true }
-serde = { version = "1.0.163", features = ["derive"] }
+thiserror = { workspace = true }
-toml = "0.7.4"
+paste = { workspace = true }
-clap = { version = "4.3.0", features = ["derive"] }
+log = { workspace = true }
-mio = { version = "0.8.6", features = ["net", "os-poll"] }
+env_logger = { workspace = true }
+serde = { workspace = true }
+toml = { workspace = true }
+clap = { workspace = true }
+mio = { workspace = true }
+rand = { workspace = true }
+command-fds = { workspace = true }
+rustix = { workspace = true }
 
 [build-dependencies]
-anyhow = "1.0.71"
+anyhow = { workspace = true }
 
 [dev-dependencies]
-criterion = "0.4.0"
+criterion = { workspace = true }
-test_bin = "0.4.0"
+test_bin = { workspace = true }
-stacker = "0.1.15"
+stacker = { workspace = true }
-
-[features]
-default = ["log", "env_logger"]

rosenpass/benches/handshake.rs

@@ -1,10 +1,8 @@
 use anyhow::Result;
-use rosenpass::pqkem::KEM;
+use rosenpass::protocol::{CryptoServer, HandleMsgResult, MsgBuf, PeerPtr, SPk, SSk, SymKey};
-use rosenpass::{
+
-    pqkem::StaticKEM,
+use rosenpass_cipher_traits::Kem;
-    protocol::{CryptoServer, HandleMsgResult, MsgBuf, PeerPtr, SPk, SSk, SymKey},
+use rosenpass_ciphers::kem::StaticKem;
-    sodium::sodium_init,
-};
 
 use criterion::{black_box, criterion_group, criterion_main, Criterion};
 
@@ -41,7 +39,7 @@ fn hs(ini: &mut CryptoServer, res: &mut CryptoServer) -> Result<()> {
 
 fn keygen() -> Result<(SSk, SPk)> {
     let (mut sk, mut pk) = (SSk::zero(), SPk::zero());
-    StaticKEM::keygen(sk.secret_mut(), pk.secret_mut())?;
+    StaticKem::keygen(sk.secret_mut(), pk.secret_mut())?;
     Ok((sk, pk))
 }
 
@@ -58,7 +56,6 @@ fn make_server_pair() -> Result<(CryptoServer, CryptoServer)> {
 }
 
 fn criterion_benchmark(c: &mut Criterion) {
-    sodium_init().unwrap();
     let (mut a, mut b) = make_server_pair().unwrap();
     c.bench_function("cca_secret_alloc", |bench| {
         bench.iter(|| {

rosenpass/src/app_server.rs

@@ -1,37 +1,26 @@
-use anyhow::bail;
+use std::cell::{Cell, RefCell};
-
+use std::io::{ErrorKind, Write};
-use anyhow::Result;
+use std::net::{Ipv4Addr, Ipv6Addr, SocketAddr, SocketAddrV4, SocketAddrV6, ToSocketAddrs};
-use log::{debug, error, info, warn};
+use std::os::unix::net::UnixStream;
-use mio::Interest;
-use mio::Token;
-
-use std::cell::Cell;
-use std::io::Write;
-
-use std::io::ErrorKind;
-use std::net::Ipv4Addr;
-use std::net::Ipv6Addr;
-use std::net::SocketAddr;
-use std::net::SocketAddrV4;
-use std::net::SocketAddrV6;
-use std::net::ToSocketAddrs;
 use std::path::PathBuf;
-use std::process::Command;
-use std::process::Stdio;
 use std::slice;
-use std::thread;
 use std::time::Duration;
 
-use crate::util::fopen_w;
+use anyhow::{bail, Result};
-use crate::{
+use log::{error, info, warn};
-    config::Verbosity,
+use mio::{Interest, Token};
-    protocol::{CryptoServer, MsgBuf, PeerPtr, SPk, SSk, SymKey, Timing},
+
-    util::{b64_writer, fmt_b64},
+use rosenpass_secret_memory::Public;
-};
+use rosenpass_util::b64::{b64_writer, fmt_b64};
+use rosenpass_util::{attempt, file::fopen_w};
+use rosenpass_wireguard_broker::api::mio_client::MioBrokerClient as PskBroker;
+use rosenpass_wireguard_broker::WireGuardBroker;
+
+use crate::config::Verbosity;
+use crate::protocol::{CryptoServer, MsgBuf, PeerPtr, SPk, SSk, SymKey, Timing};
 
 const IPV4_ANY_ADDR: Ipv4Addr = Ipv4Addr::new(0, 0, 0, 0);
 const IPV6_ANY_ADDR: Ipv6Addr = Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 0);
-
 fn ipv4_any_binding() -> SocketAddr {
     // addr, port
     SocketAddr::V4(SocketAddrV4::new(IPV4_ANY_ADDR, 0))
@@ -42,6 +31,19 @@ fn ipv6_any_binding() -> SocketAddr {
     SocketAddr::V6(SocketAddrV6::new(IPV6_ANY_ADDR, 0, 0, 0))
 }
 
+#[derive(Default)]
+struct MioTokenDispenser {
+    counter: usize,
+}
+
+impl MioTokenDispenser {
+    fn get_token(&mut self) -> Token {
+        let r = self.counter;
+        self.counter += 1;
+        Token(r)
+    }
+}
+
 #[derive(Default, Debug)]
 pub struct AppPeer {
     pub outfile: Option<PathBuf>,
@@ -58,14 +60,24 @@ impl AppPeer {
     }
 }
 
-#[derive(Default, Debug)]
+#[derive(Debug)]
 pub struct WireguardOut {
     // impl KeyOutput
     pub dev: String,
-    pub pk: String,
+    pub pk: Public<32>,
     pub extra_params: Vec<String>,
 }
 
+impl Default for WireguardOut {
+    fn default() -> Self {
+        Self {
+            dev: Default::default(),
+            pk: Public::zero(),
+            extra_params: Default::default(),
+        }
+    }
+}
+
 /// Holds the state of the application, namely the external IO
 ///
 /// Responsible for file IO, network IO
@@ -76,6 +88,7 @@ pub struct AppServer {
     pub sockets: Vec<mio::net::UdpSocket>,
     pub events: mio::Events,
     pub mio_poll: mio::Poll,
+    pub psk_broker: RefCell<PskBroker>,
     pub peers: Vec<AppPeer>,
     pub verbosity: Verbosity,
     pub all_sockets_drained: bool,
@@ -340,11 +353,24 @@ impl AppServer {
         sk: SSk,
         pk: SPk,
         addrs: Vec<SocketAddr>,
+        psk_broker_socket: UnixStream,
         verbosity: Verbosity,
     ) -> anyhow::Result<Self> {
         // setup mio
         let mio_poll = mio::Poll::new()?;
         let events = mio::Events::with_capacity(8);
+        let mut dispenser = MioTokenDispenser::default();
+
+        // Create the Wireguard broker connection
+        let psk_broker = {
+            let mut sock = mio::net::UnixStream::from_std(psk_broker_socket);
+            mio_poll.registry().register(
+                &mut sock,
+                dispenser.get_token(),
+                Interest::READABLE | Interest::WRITABLE,
+            )?;
+            PskBroker::new(sock)
+        };
 
         // bind each SocketAddr to a socket
         let maybe_sockets: Result<Vec<_>, _> =
@@ -429,6 +455,7 @@ impl AppServer {
         Ok(Self {
             crypt: CryptoServer::new(sk, pk),
             peers: Vec::new(),
+            psk_broker: RefCell::new(psk_broker),
             verbosity,
             sockets,
             events,
@@ -623,31 +650,9 @@ impl AppServer {
         }
 
         if let Some(owg) = ap.outwg.as_ref() {
-            let mut child = Command::new("wg")
+            self.psk_broker
-                .arg("set")
+                .borrow_mut()
-                .arg(&owg.dev)
+                .set_psk(&owg.dev, owg.pk.value, *key.secret())?;
-                .arg("peer")
-                .arg(&owg.pk)
-                .arg("preshared-key")
-                .arg("/dev/stdin")
-                .stdin(Stdio::piped())
-                .args(&owg.extra_params)
-                .spawn()?;
-            b64_writer(child.stdin.take().unwrap()).write_all(key.secret())?;
-
-            thread::spawn(move || {
-                let status = child.wait();
-
-                if let Ok(status) = status {
-                    if status.success() {
-                        debug!("successfully passed psk to wg")
-                    } else {
-                        error!("could not pass psk to wg {:?}", status)
-                    }
-                } else {
-                    error!("wait failed: {:?}", status)
-                }
-            });
         }
 
         Ok(())
@@ -705,9 +710,16 @@ impl AppServer {
 
         // only poll if we drained all sockets before
         if self.all_sockets_drained {
-            self.mio_poll.poll(&mut self.events, Some(timeout))?;
+            self.mio_poll
+                .poll(&mut self.events, Some(timeout))
+                .or_else(|e| match e.kind() {
+                    ErrorKind::Interrupted | ErrorKind::WouldBlock => Ok(()),
+                    _ => Err(e),
+                })?;
         }
 
+        self.psk_broker.get_mut().poll()?;
+
         let mut would_block_count = 0;
         for (sock_no, socket) in self.sockets.iter_mut().enumerate() {
             match socket.recv_from(buf) {

rosenpass/src/cli.rs

@@ -1,22 +1,54 @@
-use anyhow::{bail, ensure};
+use std::io::{BufReader, Read};
-use clap::Parser;
+use std::os::unix::net::UnixStream;
-use std::path::{Path, PathBuf};
+use std::path::PathBuf;
+use std::process::Command;
+use std::thread;
+
+use anyhow::{bail, ensure, Context};
+use clap::{ArgGroup, Parser, Subcommand};
+use command_fds::{CommandFdExt, FdMapping};
+use log::{error, info};
+use rustix::fd::AsRawFd;
+use rustix::net::{socketpair, AddressFamily, SocketFlags, SocketType};
+
+use rosenpass_cipher_traits::Kem;
+use rosenpass_ciphers::kem::StaticKem;
+use rosenpass_secret_memory::file::StoreSecret;
+use rosenpass_secret_memory::Public;
+use rosenpass_util::b64::b64_reader;
+use rosenpass_util::fd::claim_fd;
+use rosenpass_util::file::{LoadValue, LoadValueB64};
 
 use crate::app_server;
 use crate::app_server::AppServer;
-use crate::util::{LoadValue, LoadValueB64};
+use crate::protocol::{SPk, SSk, SymKey};
-use crate::{
-    // app_server::{AppServer, LoadValue, LoadValueB64},
-    coloring::Secret,
-    pqkem::{StaticKEM, KEM},
-    protocol::{SPk, SSk, SymKey},
-};
 
 use super::config;
 
 #[derive(Parser, Debug)]
+#[command(author, version, about)]
+#[clap(group(
+    ArgGroup::new("psk_broker_specs")
+    .args(&["psk_broker", "psk_broker_fd"]),
+))]
+pub struct Cli {
+    // Path of the wireguard_psk broker socket to connect to
+    #[arg(long)]
+    psk_broker: Option<PathBuf>,
+
+    /// When this command is called from another process, the other process can open and bind the
+    /// unix socket for the psk broker connectionto use themselves, passing it to this process. In Rust this can be achieved
+    /// using the [command-fds](https://docs.rs/command-fds/latest/command_fds/) crate.
+    #[arg(long)]
+    psk_broker_fd: Option<i32>,
+
+    #[command(subcommand)]
+    pub command: CliCommand,
+}
+
+#[derive(Subcommand, Debug)]
 #[command(author, version, about, long_about)]
-pub enum Cli {
+pub enum CliCommand {
     /// Start Rosenpass in server mode and carry on with the key exchange
     ///
     /// This will parse the configuration file and perform the key exchange
@@ -64,6 +96,7 @@ pub enum Cli {
         config_file: PathBuf,
 
         /// Forcefully overwrite existing config file
+        /// - [ ] Janepie
         #[clap(short, long)]
         force: bool,
     },
@@ -89,6 +122,15 @@ pub enum Cli {
         force: bool,
     },
 
+    /// Deprecated - use gen-keys instead
+    #[allow(rustdoc::broken_intra_doc_links)]
+    #[allow(rustdoc::invalid_html_tags)]
+    Keygen {
+        // NOTE yes, the legacy keygen argument initially really accepted "privet-key", not "secret-key"!
+        /// public-key <PATH> private-key <PATH>
+        args: Vec<String>,
+    },
+
     /// Validate a configuration
     Validate { config_files: Vec<PathBuf> },
 
@@ -101,9 +143,9 @@ impl Cli {
     pub fn run() -> anyhow::Result<()> {
         let cli = Self::parse();
 
-        use Cli::*;
+        use CliCommand::*;
         match cli {
-            Man => {
+            Cli { command: Man, .. } => {
                 let man_cmd = std::process::Command::new("man")
                     .args(["1", "rosenpass"])
                     .status();
@@ -112,7 +154,10 @@ impl Cli {
                     println!(include_str!(env!("ROSENPASS_MAN")));
                 }
             }
-            GenConfig { config_file, force } => {
+            Cli {
+                command: GenConfig { config_file, force },
+                ..
+            } => {
                 ensure!(
                     force || !config_file.exists(),
                     "config file {config_file:?} already exists"
@@ -121,11 +166,52 @@ impl Cli {
                 config::Rosenpass::example_config().store(config_file)?;
             }
 
-            GenKeys {
+            // Deprecated - use gen-keys instead
-                config_file,
+            Cli {
-                public_key,
+                command: Keygen { args },
-                secret_key,
+                ..
-                force,
+            } => {
+                log::warn!("The 'keygen' command is deprecated. Please use the 'gen-keys' command instead.");
+
+                let mut public_key: Option<PathBuf> = None;
+                let mut secret_key: Option<PathBuf> = None;
+
+                // Manual arg parsing, since clap wants to prefix flags with "--"
+                let mut args = args.into_iter();
+                loop {
+                    match (args.next().as_deref(), args.next()) {
+                        (Some("private-key"), Some(opt)) | (Some("secret-key"), Some(opt)) => {
+                            secret_key = Some(opt.into());
+                        }
+                        (Some("public-key"), Some(opt)) => {
+                            public_key = Some(opt.into());
+                        }
+                        (Some(flag), _) => {
+                            bail!("Unknown option `{}`", flag);
+                        }
+                        (_, _) => break,
+                    };
+                }
+
+                if secret_key.is_none() {
+                    bail!("private-key is required");
+                }
+                if public_key.is_none() {
+                    bail!("public-key is required");
+                }
+
+                generate_and_save_keypair(secret_key.unwrap(), public_key.unwrap())?;
+            }
+
+            Cli {
+                command:
+                    GenKeys {
+                        config_file,
+                        public_key,
+                        secret_key,
+                        force,
+                    },
+                ..
             } => {
                 // figure out where the key file is specified, in the config file or directly as flag?
                 let (pkf, skf) = match (config_file, public_key, secret_key) {
@@ -162,15 +248,13 @@ impl Cli {
                 }
 
                 // generate the keys and store them in files
-                let mut ssk = crate::protocol::SSk::random();
+                generate_and_save_keypair(skf, pkf)?;
-                let mut spk = crate::protocol::SPk::random();
-                StaticKEM::keygen(ssk.secret_mut(), spk.secret_mut())?;
-
-                ssk.store_secret(skf)?;
-                spk.store_secret(pkf)?;
             }
 
-            ExchangeConfig { config_file } => {
+            ref cli @ Cli {
+                command: ExchangeConfig { ref config_file },
+                ..
+            } => {
                 ensure!(
                     config_file.exists(),
                     "config file '{config_file:?}' does not exist"
@@ -178,33 +262,41 @@ impl Cli {
 
                 let config = config::Rosenpass::load(config_file)?;
                 config.validate()?;
-                Self::event_loop(config)?;
+                Self::event_loop(&cli, &config)?;
             }
 
-            Exchange {
+            ref cli @ Cli {
-                first_arg,
+                command:
-                mut rest_of_args,
+                    Exchange {
-                config_file,
+                        ref first_arg,
+                        ref rest_of_args,
+                        ref config_file,
+                    },
+                ..
             } => {
-                rest_of_args.insert(0, first_arg);
+                let mut args = Vec::new();
-                let args = rest_of_args;
+                args.push(first_arg.clone());
+                args.extend_from_slice(&rest_of_args[..]);
                 let mut config = config::Rosenpass::parse_args(args)?;
 
-                if let Some(p) = config_file {
+                if let Some(p) = &config_file {
                     config.store(&p)?;
-                    config.config_file_path = p;
+                    config.config_file_path = p.clone();
                 }
                 config.validate()?;
-                Self::event_loop(config)?;
+                Self::event_loop(&cli, &config)?;
             }
 
-            Validate { config_files } => {
+            Cli {
+                command: Validate { config_files },
+                ..
+            } => {
                 for file in config_files {
                     match config::Rosenpass::load(&file) {
                         Ok(config) => {
                             eprintln!("{file:?} is valid TOML and conforms to the expected schema");
                             match config.validate() {
-                                Ok(_) => eprintln!("{file:?} is passed all logical checks"),
+                                Ok(_) => eprintln!("{file:?} has passed all logical checks"),
                                 Err(_) => eprintln!("{file:?} contains logical errors"),
                             }
                         }
@@ -217,30 +309,99 @@ impl Cli {
         Ok(())
     }
 
-    fn event_loop(config: config::Rosenpass) -> anyhow::Result<()> {
+    fn event_loop(cli: &Cli, config: &config::Rosenpass) -> anyhow::Result<()> {
         // load own keys
         let sk = SSk::load(&config.secret_key)?;
         let pk = SPk::load(&config.public_key)?;
 
+        // Connect to the psk broker unix socket if one was specified
+        // OR OTHERWISE pawn the psk broker and use socketpair(2) to connect with them
+        let psk_broker_socket = if let Some(ref broker_path) = cli.psk_broker {
+            let sock = UnixStream::connect(broker_path)?;
+            sock.set_nonblocking(true)?;
+            sock
+        } else if let Some(broker_fd) = cli.psk_broker_fd {
+            let sock = UnixStream::from(claim_fd(broker_fd)?);
+            sock.set_nonblocking(true)?;
+            sock
+        } else {
+            let (ours, theirs) = socketpair(
+                AddressFamily::UNIX,
+                SocketType::STREAM,
+                SocketFlags::empty(),
+                None,
+            )?;
+
+            // Setup our end of the socketpair
+            let ours = UnixStream::from(ours);
+            ours.set_nonblocking(true)?;
+
+            // Start the PSK broker
+            let mut child = Command::new("rosenpass-wireguard-broker-socket-handler")
+                .args(&["--stream-fd", "3"])
+                .fd_mappings(vec![FdMapping {
+                    parent_fd: theirs.as_raw_fd(),
+                    child_fd: 3,
+                }])?
+                .spawn()?;
+
+            // Handle the PSK broker crashing
+            thread::spawn(move || {
+                let status = child.wait();
+
+                if let Ok(status) = status {
+                    if status.success() {
+                        // Maybe they are doing double forking?
+                        info!("PSK broker exited.");
+                    } else {
+                        error!("PSK broker exited with an error ({status:?})");
+                    }
+                } else {
+                    error!("Wait on PSK broker process failed ({status:?})");
+                }
+            });
+
+            ours
+        };
+
         // start an application server
         let mut srv = std::boxed::Box::<AppServer>::new(AppServer::new(
             sk,
             pk,
-            config.listen,
+            config.listen.clone(),
-            config.verbosity,
+            psk_broker_socket,
+            config.verbosity.clone(),
         )?);
 
-        for cfg_peer in config.peers {
+        for cfg_peer in config.peers.iter().by_ref() {
             srv.add_peer(
                 // psk, pk, outfile, outwg, tx_addr
-                cfg_peer.pre_shared_key.map(SymKey::load_b64).transpose()?,
+                cfg_peer
+                    .pre_shared_key
+                    .as_ref()
+                    .map(SymKey::load_b64)
+                    .transpose()?,
                 SPk::load(&cfg_peer.public_key)?,
-                cfg_peer.key_out,
+                cfg_peer.key_out.clone(),
-                cfg_peer.wg.map(|cfg| app_server::WireguardOut {
+                cfg_peer
-                    dev: cfg.device,
+                    .wg
-                    pk: cfg.peer,
+                    .as_ref()
-                    extra_params: cfg.extra_params,
+                    .map(|cfg| -> anyhow::Result<_> {
-                }),
+                        let b64pk = &cfg.peer;
+                        let mut pk = Public::zero();
+                        b64_reader(BufReader::new(b64pk.as_bytes()))
+                            .read_exact(&mut pk.value)
+                            .with_context(|| {
+                                format!("Could not decode base64 public key: '{b64pk}'")
+                            })?;
+
+                        Ok(app_server::WireguardOut {
+                            pk,
+                            dev: cfg.device.clone(),
+                            extra_params: cfg.extra_params.clone(),
+                        })
+                    })
+                    .transpose()?,
                 cfg_peer.endpoint.clone(),
             )?;
         }
@@ -249,13 +410,11 @@ impl Cli {
     }
 }
 
-trait StoreSecret {
+/// generate secret and public keys, store in files according to the paths passed as arguments
-    fn store_secret<P: AsRef<Path>>(&self, path: P) -> anyhow::Result<()>;
+fn generate_and_save_keypair(secret_key: PathBuf, public_key: PathBuf) -> anyhow::Result<()> {
-}
+    let mut ssk = crate::protocol::SSk::random();
-
+    let mut spk = crate::protocol::SPk::random();
-impl<const N: usize> StoreSecret for Secret<N> {
+    StaticKem::keygen(ssk.secret_mut(), spk.secret_mut())?;
-    fn store_secret<P: AsRef<Path>>(&self, path: P) -> anyhow::Result<()> {
+    ssk.store_secret(secret_key)?;
-        std::fs::write(path, self.secret())?;
+    spk.store_secret(public_key)
-        Ok(())
-    }
 }

rosenpass/src/coloring.rs

@@ -1,361 +0,0 @@
-//! Types types for dealing with (secret-) values
-//!
-//! These types use type level coloring to make accidential leackage of secrets extra hard. Both [Secret] and [Public] own their data, but the memory backing
-//! [Secret] is special:
-//! - as it is heap allocated, we can actively zeroize the memory before freeing it.
-//! - guard pages before and after each allocation trap accidential sequential reads that creep towards our secrets
-//! - the memory is mlocked, e.g. it is never swapped
-
-use crate::{
-    sodium::{rng, zeroize},
-    util::{cpy, mutating},
-};
-use lazy_static::lazy_static;
-use libsodium_sys as libsodium;
-use std::{
-    collections::HashMap,
-    convert::TryInto,
-    fmt,
-    ops::{Deref, DerefMut},
-    os::raw::c_void,
-    ptr::null_mut,
-    sync::Mutex,
-};
-
-// This might become a problem in library usage; it's effectively a memory
-// leak which probably isn't a problem right now because most memory will
-// be reused…
-lazy_static! {
-    static ref SECRET_CACHE: Mutex<SecretMemoryPool> = Mutex::new(SecretMemoryPool::new());
-}
-
-/// Pool that stores secret memory allocations
-///
-/// Allocation of secret memory is expensive. Thus, this struct provides a
-/// pool of secret memory, readily available to yield protected, slices of
-/// memory.
-///
-/// Further information about the protection in place can be found in in the
-/// [libsodium documentation](https://libsodium.gitbook.io/doc/memory_management#guarded-heap-allocations)
-#[derive(Debug)] // TODO check on Debug derive, is that clever
-pub struct SecretMemoryPool {
-    pool: HashMap<usize, Vec<*mut c_void>>,
-}
-
-impl SecretMemoryPool {
-    /// Create a new [SecretMemoryPool]
-    #[allow(clippy::new_without_default)]
-    pub fn new() -> Self {
-        let pool = HashMap::new();
-
-        Self { pool }
-    }
-
-    /// Return secrete back to the pool for future re-use
-    ///
-    /// This consumes the [Secret], but its memory is re-used.
-    pub fn release<const N: usize>(&mut self, mut s: Secret<N>) {
-        unsafe {
-            self.release_by_ref(&mut s);
-        }
-        std::mem::forget(s);
-    }
-
-    /// Return secret back to the pool for future re-use, by slice
-    ///
-    /// # Safety
-    ///
-    /// After calling this function on a [Secret], the secret must never be
-    /// used again for anything.
-    unsafe fn release_by_ref<const N: usize>(&mut self, s: &mut Secret<N>) {
-        s.zeroize();
-        let Secret { ptr: secret } = s;
-        // don't call Secret::drop, that could cause a double free
-        self.pool.entry(N).or_default().push(*secret);
-    }
-
-    /// Take protected memory from the pool, allocating new one if no suitable
-    /// chunk is found in the inventory.
-    ///
-    /// The secret is guaranteed to be full of nullbytes
-    ///
-    /// # Safety
-    ///
-    /// This function contains an unsafe call to [libsodium::sodium_malloc].
-    /// This call has no known safety invariants, thus nothing can go wrong™.
-    /// However, just like normal `malloc()` this can return a null ptr. Thus
-    /// the returned pointer is checked for null; causing the program to panic
-    /// if it is null.
-    pub fn take<const N: usize>(&mut self) -> Secret<N> {
-        let entry = self.pool.entry(N).or_default();
-        let secret = entry.pop().unwrap_or_else(|| {
-            let ptr = unsafe { libsodium::sodium_malloc(N) };
-            assert!(
-                !ptr.is_null(),
-                "libsodium::sodium_mallloc() returned a null ptr"
-            );
-            ptr
-        });
-
-        let mut s = Secret { ptr: secret };
-        s.zeroize();
-        s
-    }
-}
-
-impl Drop for SecretMemoryPool {
-    /// # Safety
-    ///
-    /// The drop implementation frees the contained elements using
-    /// [libsodium::sodium_free]. This is safe as long as every `*mut c_void`
-    /// contained was initialized with a call to [libsodium::sodium_malloc]
-    fn drop(&mut self) {
-        for ptr in self.pool.drain().flat_map(|(_, x)| x.into_iter()) {
-            unsafe {
-                libsodium::sodium_free(ptr);
-            }
-        }
-    }
-}
-
-/// # Safety
-///
-/// No safety implications are known, since the `*mut c_void` in
-/// is essentially used like a `&mut u8` [SecretMemoryPool].
-unsafe impl Send for SecretMemoryPool {}
-
-/// Store for a secret
-///
-/// Uses memory allocated with [libsodium::sodium_malloc],
-/// esentially can do the same things as `[u8; N].as_mut_ptr()`.
-pub struct Secret<const N: usize> {
-    ptr: *mut c_void,
-}
-
-impl<const N: usize> Clone for Secret<N> {
-    fn clone(&self) -> Self {
-        let mut new = Self::zero();
-        new.secret_mut().clone_from_slice(self.secret());
-        new
-    }
-}
-
-impl<const N: usize> Drop for Secret<N> {
-    fn drop(&mut self) {
-        self.zeroize();
-        // the invariant that the [Secret] is not used after the
-        // `release_by_ref` call is guaranteed, since this is a drop implementation
-        unsafe { SECRET_CACHE.lock().unwrap().release_by_ref(self) };
-        self.ptr = null_mut();
-    }
-}
-
-impl<const N: usize> Secret<N> {
-    pub fn from_slice(slice: &[u8]) -> Self {
-        let mut new_self = Self::zero();
-        new_self.secret_mut().copy_from_slice(slice);
-        new_self
-    }
-
-    /// Returns a new [Secret] that is zero initialized
-    pub fn zero() -> Self {
-        // Using [SecretMemoryPool] here because this operation is expensive,
-        // yet it is used in hot loops
-        let s = SECRET_CACHE.lock().unwrap().take();
-        assert_eq!(s.secret(), &[0u8; N]);
-        s
-    }
-
-    /// Returns a new [Secret] that is randomized
-    pub fn random() -> Self {
-        mutating(Self::zero(), |r| r.randomize())
-    }
-
-    /// Sets all data of an existing secret to null bytes
-    pub fn zeroize(&mut self) {
-        zeroize(self.secret_mut());
-    }
-
-    /// Sets all data an existing secret to random bytes
-    pub fn randomize(&mut self) {
-        rng(self.secret_mut());
-    }
-
-    /// Borrows the data
-    pub fn secret(&self) -> &[u8; N] {
-        // - calling `from_raw_parts` is safe, because `ptr` is initalized with
-        //   as `N` byte allocation from the creation of `Secret` onwards. `ptr`
-        //   stays valid over the full lifetime of `Secret`
-        //
-        // - calling uwnrap is safe, because we can guarantee that the slice has
-        //   exactly the required size `N` to create an array of `N` elements.
-        let ptr = self.ptr as *const u8;
-        let slice = unsafe { std::slice::from_raw_parts(ptr, N) };
-        slice.try_into().unwrap()
-    }
-
-    /// Borrows the data mutably
-    pub fn secret_mut(&mut self) -> &mut [u8; N] {
-        // the same safety argument as for `secret()` holds
-        let ptr = self.ptr as *mut u8;
-        let slice = unsafe { std::slice::from_raw_parts_mut(ptr, N) };
-        slice.try_into().unwrap()
-    }
-}
-
-/// The Debug implementation of [Secret] does not reveal the secret data,
-/// instead a placeholder `<SECRET>` is used
-impl<const N: usize> fmt::Debug for Secret<N> {
-    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        fmt.write_str("<SECRET>")
-    }
-}
-
-/// Contains information in the form of a byte array that may be known to the
-/// public
-// TODO: We should get rid of the Public type; just use a normal value
-#[derive(Copy, Clone, Hash, PartialEq, Eq, PartialOrd, Ord)]
-#[repr(transparent)]
-pub struct Public<const N: usize> {
-    pub value: [u8; N],
-}
-
-impl<const N: usize> Public<N> {
-    /// Create a new [Public] from a byte slice
-    pub fn from_slice(value: &[u8]) -> Self {
-        mutating(Self::zero(), |r| cpy(value, &mut r.value))
-    }
-
-    /// Create a new [Public] from a byte array
-    pub fn new(value: [u8; N]) -> Self {
-        Self { value }
-    }
-
-    /// Create a zero initialized [Public]
-    pub fn zero() -> Self {
-        Self { value: [0u8; N] }
-    }
-
-    /// Create a random initialized [Public]
-    pub fn random() -> Self {
-        mutating(Self::zero(), |r| r.randomize())
-    }
-
-    /// Randomize all bytes in an existing [Public]
-    pub fn randomize(&mut self) {
-        rng(&mut self.value);
-    }
-}
-
-/// Writes the contents of an `&[u8]` as hexadecimal symbols to a [std::fmt::Formatter]
-pub fn debug_crypto_array(v: &[u8], fmt: &mut fmt::Formatter) -> fmt::Result {
-    fmt.write_str("[{}]=")?;
-    if v.len() > 64 {
-        for byte in &v[..32] {
-            std::fmt::LowerHex::fmt(byte, fmt)?;
-        }
-        fmt.write_str("…")?;
-        for byte in &v[v.len() - 32..] {
-            std::fmt::LowerHex::fmt(byte, fmt)?;
-        }
-    } else {
-        for byte in v {
-            std::fmt::LowerHex::fmt(byte, fmt)?;
-        }
-    }
-    Ok(())
-}
-
-impl<const N: usize> fmt::Debug for Public<N> {
-    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        debug_crypto_array(&self.value, fmt)
-    }
-}
-
-impl<const N: usize> Deref for Public<N> {
-    type Target = [u8; N];
-
-    fn deref(&self) -> &[u8; N] {
-        &self.value
-    }
-}
-
-impl<const N: usize> DerefMut for Public<N> {
-    fn deref_mut(&mut self) -> &mut [u8; N] {
-        &mut self.value
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use super::*;
-
-    /// https://libsodium.gitbook.io/doc/memory_management#guarded-heap-allocations
-    /// promises us that allocated memory is initialized with this magic byte
-    const SODIUM_MAGIC_BYTE: u8 = 0xdb;
-
-    /// must be called before any interaction with libsodium
-    fn init() {
-        unsafe { libsodium_sys::sodium_init() };
-    }
-
-    /// checks that whe can malloc with libsodium
-    #[test]
-    fn sodium_malloc() {
-        init();
-        const N: usize = 8;
-        let ptr = unsafe { libsodium_sys::sodium_malloc(N) };
-        let mem = unsafe { std::slice::from_raw_parts(ptr as *mut u8, N) };
-        assert_eq!(mem, &[SODIUM_MAGIC_BYTE; N])
-    }
-
-    /// checks that whe can free with libsodium
-    #[test]
-    fn sodium_free() {
-        init();
-        const N: usize = 8;
-        let ptr = unsafe { libsodium_sys::sodium_malloc(N) };
-        unsafe { libsodium_sys::sodium_free(ptr) }
-    }
-
-    /// check that we can alloc using the magic pool
-    #[test]
-    fn secret_memory_pool_take() {
-        init();
-        const N: usize = 0x100;
-        let mut pool = SecretMemoryPool::new();
-        let secret: Secret<N> = pool.take();
-        assert_eq!(secret.secret(), &[0; N]);
-    }
-
-    /// check that a secrete lives, even if its [SecretMemoryPool] is deleted
-    #[test]
-    fn secret_memory_pool_drop() {
-        init();
-        const N: usize = 0x100;
-        let mut pool = SecretMemoryPool::new();
-        let secret: Secret<N> = pool.take();
-        std::mem::drop(pool);
-        assert_eq!(secret.secret(), &[0; N]);
-    }
-
-    /// check that a secrete can be reborn, freshly initialized with zero
-    #[test]
-    fn secret_memory_pool_release() {
-        init();
-        const N: usize = 1;
-        let mut pool = SecretMemoryPool::new();
-        let mut secret: Secret<N> = pool.take();
-        let old_secret_ptr = secret.ptr;
-
-        secret.secret_mut()[0] = 0x13;
-        pool.release(secret);
-
-        // now check that we get the same ptr
-        let new_secret: Secret<N> = pool.take();
-        assert_eq!(old_secret_ptr, new_secret.ptr);
-
-        // and that the secret was zeroized
-        assert_eq!(new_secret.secret(), &[0; N]);
-    }
-}

rosenpass/src/config.rs

@@ -7,10 +7,9 @@ use std::{
 };
 
 use anyhow::{bail, ensure};
+use rosenpass_util::file::fopen_w;
 use serde::{Deserialize, Serialize};
 
-use crate::util::fopen_w;
-
 #[derive(Debug, Serialize, Deserialize)]
 pub struct Rosenpass {
     pub public_key: PathBuf,
@@ -27,7 +26,7 @@ pub struct Rosenpass {
     pub config_file_path: PathBuf,
 }
 
-#[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
+#[derive(Debug, PartialEq, Eq, Serialize, Deserialize, Clone)]
 pub enum Verbosity {
     Quiet,
     Verbose,
@@ -42,10 +41,6 @@ pub struct RosenpassPeer {
     #[serde(default)]
     pub key_out: Option<PathBuf>,
 
-    // TODO make sure failure does not crash but is logged
-    #[serde(default)]
-    pub exchange_command: Vec<String>,
-
     // TODO make this field only available on binary builds, not on library builds
     #[serde(flatten)]
     pub wg: Option<WireGuard>,
@@ -346,28 +341,20 @@ impl Rosenpass {
     /// Generate an example configuration
     pub fn example_config() -> Self {
         let peer = RosenpassPeer {
-            public_key: "rp-peer-public-key".into(),
+            public_key: "/path/to/rp-peer-public-key".into(),
             endpoint: Some("my-peer.test:9999".into()),
-            exchange_command: [
+            key_out: Some("/path/to/rp-key-out.txt".into()),
-                "wg",
+            pre_shared_key: Some("additional pre shared key".into()),
-                "set",
+            wg: Some(WireGuard {
-                "wg0",
+                device: "wirgeguard device e.g. wg0".into(),
-                "peer",
+                peer: "wireguard public key".into(),
-                "<PEER_ID>",
+                extra_params: vec!["passed to".into(), "wg set".into()],
-                "preshared-key",
+            }),
-                "/dev/stdin",
-            ]
-            .into_iter()
-            .map(|x| x.to_string())
-            .collect(),
-            key_out: Some("rp-key-out".into()),
-            pre_shared_key: None,
-            wg: None,
         };
 
         Self {
-            public_key: "rp-public-key".into(),
+            public_key: "/path/to/rp-public-key".into(),
-            secret_key: "rp-secret-key".into(),
+            secret_key: "/path/to/rp-secret-key".into(),
             peers: vec![peer],
             ..Self::new("", "")
         }
@@ -387,7 +374,7 @@ mod test {
     use super::*;
 
     fn split_str(s: &str) -> Vec<String> {
-        s.split(" ").map(|s| s.to_string()).collect()
+        s.split(' ').map(|s| s.to_string()).collect()
     }
 
     #[test]

rosenpass/src/hash_domains.rs

@@ -0,0 +1,46 @@
+//! Pseudo Random Functions (PRFs) with a tree-like label scheme which
+//! ensures their uniqueness
+
+use anyhow::Result;
+use rosenpass_ciphers::{hash_domain::HashDomain, KEY_LEN};
+
+// TODO Use labels that can serve as identifiers
+macro_rules! hash_domain_ns {
+    ($base:ident, $name:ident, $($lbl:expr),* ) => {
+        pub fn $name() -> Result<HashDomain> {
+            let t = $base()?;
+            $( let t = t.mix($lbl.as_bytes())?; )*
+            Ok(t)
+        }
+    }
+}
+
+macro_rules! hash_domain {
+    ($base:ident, $name:ident, $($lbl:expr),* ) => {
+        pub fn $name() -> Result<[u8; KEY_LEN]> {
+            let t = $base()?;
+            $( let t = t.mix($lbl.as_bytes())?; )*
+            Ok(t.into_value())
+        }
+    }
+}
+
+pub fn protocol() -> Result<HashDomain> {
+    HashDomain::zero().mix("Rosenpass v1 mceliece460896 Kyber512 ChaChaPoly1305 BLAKE2s".as_bytes())
+}
+
+hash_domain_ns!(protocol, mac, "mac");
+hash_domain_ns!(protocol, cookie, "cookie");
+hash_domain_ns!(protocol, peerid, "peer id");
+hash_domain_ns!(protocol, biscuit_ad, "biscuit additional data");
+hash_domain_ns!(protocol, ckinit, "chaining key init");
+hash_domain_ns!(protocol, _ckextract, "chaining key extract");
+
+hash_domain!(_ckextract, mix, "mix");
+hash_domain!(_ckextract, hs_enc, "handshake encryption");
+hash_domain!(_ckextract, ini_enc, "initiator handshake encryption");
+hash_domain!(_ckextract, res_enc, "responder handshake encryption");
+
+hash_domain_ns!(_ckextract, _user, "user");
+hash_domain_ns!(_user, _rp, "rosenpass.eu");
+hash_domain!(_rp, osk, "wireguard psk");

rosenpass/src/labeled_prf.rs

@@ -1,48 +0,0 @@
-//! Pseudo Random Functions (PRFs) with a tree-like label scheme which
-//! ensures their uniqueness
-
-use {
-    crate::{prftree::PrfTree, sodium::KEY_SIZE},
-    anyhow::Result,
-};
-
-pub fn protocol() -> Result<PrfTree> {
-    PrfTree::zero().mix("Rosenpass v1 mceliece460896 Kyber512 ChaChaPoly1305 BLAKE2s".as_bytes())
-}
-
-// TODO Use labels that can serve as identifiers
-macro_rules! prflabel {
-    ($base:ident, $name:ident, $($lbl:expr),* ) => {
-        pub fn $name() -> Result<PrfTree> {
-            let t = $base()?;
-            $( let t = t.mix($lbl.as_bytes())?; )*
-            Ok(t)
-        }
-    }
-}
-
-prflabel!(protocol, mac, "mac");
-prflabel!(protocol, cookie, "cookie");
-prflabel!(protocol, peerid, "peer id");
-prflabel!(protocol, biscuit_ad, "biscuit additional data");
-prflabel!(protocol, ckinit, "chaining key init");
-prflabel!(protocol, _ckextract, "chaining key extract");
-
-macro_rules! prflabel_leaf {
-    ($base:ident, $name:ident, $($lbl:expr),* ) => {
-        pub fn $name() -> Result<[u8; KEY_SIZE]> {
-            let t = $base()?;
-            $( let t = t.mix($lbl.as_bytes())?; )*
-            Ok(t.into_value())
-        }
-    }
-}
-
-prflabel_leaf!(_ckextract, mix, "mix");
-prflabel_leaf!(_ckextract, hs_enc, "handshake encryption");
-prflabel_leaf!(_ckextract, ini_enc, "initiator handshake encryption");
-prflabel_leaf!(_ckextract, res_enc, "responder handshake encryption");
-
-prflabel!(_ckextract, _user, "user");
-prflabel!(_user, _rp, "rosenpass.eu");
-prflabel_leaf!(_rp, osk, "wireguard psk");

rosenpass/src/lib.rs

@@ -1,60 +1,24 @@
-#[macro_use]
+use rosenpass_lenses::LenseError;
-pub mod util;
+
-#[macro_use]
-pub mod sodium;
-pub mod coloring;
-#[rustfmt::skip]
-pub mod labeled_prf;
 pub mod app_server;
 pub mod cli;
 pub mod config;
+pub mod hash_domains;
 pub mod msgs;
-pub mod pqkem;
-pub mod prftree;
 pub mod protocol;
 
 #[derive(thiserror::Error, Debug)]
 pub enum RosenpassError {
-    #[error("error in OQS")]
+    #[error("buffer size mismatch")]
-    Oqs,
+    BufferSizeMismatch,
-    #[error("error from external library while calling OQS")]
-    OqsExternalLib,
-    #[error("buffer size mismatch, required {required_size} but found {actual_size}")]
-    BufferSizeMismatch {
-        required_size: usize,
-        actual_size: usize,
-    },
     #[error("invalid message type")]
     InvalidMessageType(u8),
 }
 
-impl RosenpassError {
+impl From<LenseError> for RosenpassError {
-    /// Helper function to check a buffer size
+    fn from(value: LenseError) -> Self {
-    fn check_buffer_size(required_size: usize, actual_size: usize) -> Result<(), Self> {
+        match value {
-        if required_size != actual_size {
+            LenseError::BufferSizeMismatch => RosenpassError::BufferSizeMismatch,
-            Err(Self::BufferSizeMismatch {
-                required_size,
-                actual_size,
-            })
-        } else {
-            Ok(())
-        }
-    }
-}
-
-/// Extension trait to attach function calls to foreign types.
-trait RosenpassMaybeError {
-    /// Checks whether something is an error or not
-    fn to_rg_error(&self) -> Result<(), RosenpassError>;
-}
-
-impl RosenpassMaybeError for oqs_sys::common::OQS_STATUS {
-    fn to_rg_error(&self) -> Result<(), RosenpassError> {
-        use oqs_sys::common::OQS_STATUS;
-        match self {
-            OQS_STATUS::OQS_SUCCESS => Ok(()),
-            OQS_STATUS::OQS_ERROR => Err(RosenpassError::Oqs),
-            OQS_STATUS::OQS_EXTERNAL_LIB_ERROR_OPENSSL => Err(RosenpassError::OqsExternalLib),
         }
     }
 }

rosenpass/src/lprf.rs

@@ -1,107 +0,0 @@
-//! The rosenpass protocol relies on a special type
-//! of hash function for most of its hashing or
-//! message authentication needs: an incrementable
-//! pseudo random function.
-//!
-//! This is a generalization of a PRF operating
-//! on a sequence of inputs instead of a single input.
-//!
-//! Like a Dec function the Iprf features efficient
-//! incrementability.
-//!
-//! You can also think of an Iprf as a Dec function with
-//! a fixed size output.
-//!
-//! The idea behind a Iprf is that it can be efficiently
-//! constructed from an Dec function as well as a PRF.
-//!
-//! TODO Base the construction on a proper Dec function
-
-pub struct Iprf([u8; KEY_SIZE]);
-pub struct IprfBranch([u8; KEY_SIZE]);
-pub struct SecretIprf(Secret<KEY_SIZE>);
-pub struct SecretIprfBranch(Secret<KEY_SIZE>);
-
-pub fn prf_into(out: &mut [u8], key: &[u8], data: &[u8]) {
-    // TODO: The error handling with sodium is a scurge
-    hmac_into(out, key, data).unwrap()
-}
-
-pub fn prf(key: &[u8], data: &[u8]) -> [u8; KEY_SIZE] {
-    mutating([0u8; KEY_SIZE], |r| prf_into(r, key, data))
-}
-
-impl Iprf {
-    fn zero() -> Self {
-        Self([0u8; KEY_SIZE])
-    }
-
-    fn dup(self) -> IprfBranch {
-        IprfBranch(self.0)
-    }
-
-    // TODO: Protocol! Use domain separation to ensure that
-    fn mix(self, v: &[u8]) -> Self {
-        Self(prf(&self.0, v))
-    }
-
-    fn mix_secret<const N: usize>(self, v: Secret<N>) -> SecretIprf {
-        SecretIprf::prf_invoc(&self.0, v.secret())
-    }
-
-    fn into_value(self) -> [u8; KEY_SIZE] {
-        self.0
-    }
-
-    fn extract(self, v: &[u8], dst: &mut [u8]) {
-        prf_into(&self.0, v, dst)
-    }
-}
-
-impl IprfBranch {
-    fn mix(&self, v: &[u8]) -> Iprf {
-        Iprf(prf(self.0, v))
-    }
-
-    fn mix_secret<const N: usize>(&self, v: Secret<N>) -> SecretIprf {
-        SecretIprf::prf_incov(self.0, v.secret())
-    }
-}
-
-impl SecretIprf {
-    fn prf_invoc(k: &[u8], d: &[u8]) -> SecretIprf {
-        mutating(SecretIprf(Secret::zero()), |r| {
-            prf_into(k, d, r.secret_mut())
-        })
-    }
-
-    fn from_key(k: Secret<N>) -> SecretIprf {
-        Self(k)
-    }
-
-    fn mix(self, v: &[u8]) -> SecretIprf {
-        Self::prf_invoc(self.0.secret(), v)
-    }
-
-    fn mix_secret<const N: usize>(self, v: Secret<N>) -> SecretIprf {
-        Self::prf_invoc(self.0.secret(), v.secret())
-    }
-
-    fn into_secret(self) -> Secret<KEY_SIZE> {
-        self.0
-    }
-
-    fn into_secret_slice(self, v: &[u8], dst: &[u8]) {
-        prf_into(self.0.secret(), v, dst)
-    }
-}
-
-impl SecretIprfBranch {
-    fn mix(&self, v: &[u8]) -> SecretIprf {
-        SecretIprf::prf_invoc(self.0.secret(), v)
-    }
-
-    fn mix_secret<const N: usize>(&self, v: Secret<N>) -> SecretIprf {
-        SecretIprf::prf_invoc(self.0.secret(), v.secret())
-    }
-}

rosenpass/src/main.rs

@@ -1,14 +1,16 @@
 use log::error;
-use rosenpass::{cli::Cli, sodium::sodium_init};
+use rosenpass::cli::Cli;
 use std::process::exit;
 
 /// Catches errors, prints them through the logger, then exits
 pub fn main() {
-    env_logger::init();
+    // default to displaying warning and error log messages only
-    match sodium_init().and_then(|()| Cli::run()) {
+    env_logger::Builder::from_env(env_logger::Env::default().default_filter_or("warn")).init();
+
+    match Cli::run() {
         Ok(_) => {}
         Err(e) => {
-            error!("{e}");
+            error!("{e:?}");
             exit(1);
         }
     }

rosenpass/src/msgs.rs

@@ -9,14 +9,15 @@
 //!
 //! # Example
 //!
-//! The following example uses the [`data_lense` macro](crate::data_lense) to create a lense that
+//! The following example uses the [`lense` macro](rosenpass_lenses::lense) to create a lense that
 //! might be useful when dealing with UDP headers.
 //!
 //! ```
-//! use rosenpass::{data_lense, RosenpassError, msgs::LenseView};
+//! use rosenpass_lenses::{lense, LenseView};
+//! use rosenpass::RosenpassError;
 //! # fn main() -> Result<(), RosenpassError> {
 //!
-//! data_lense! {UdpDatagramHeader :=
+//! lense! {UdpDatagramHeader :=
 //!     source_port: 2,
 //!     dest_port: 2,
 //!     length: 2,
@@ -44,215 +45,14 @@
 //! ```
 
 use super::RosenpassError;
-use crate::{pqkem::*, sodium};
+use rosenpass_cipher_traits::Kem;
+use rosenpass_ciphers::kem::{EphemeralKem, StaticKem};
+use rosenpass_ciphers::{aead, xaead, KEY_LEN};
+use rosenpass_lenses::{lense, LenseView};
 
 // Macro magic ////////////////////////////////////////////////////////////////
 
-/// A macro to create data lenses. Refer to the [`msgs` mod](crate::msgs) for
+lense! { Envelope<M> :=
-/// an example and further elaboration
-// TODO implement TryFrom<[u8]> and From<[u8; Self::len()]>
-#[macro_export]
-macro_rules! data_lense(
-    // prefix          @ offset       ; optional meta    ; field name   : field length, ...
-    (token_muncher_ref @ $offset:expr ; $( $attr:meta )* ; $field:ident : $len:expr $(, $( $tail:tt )+ )?) =>  {
-        ::paste::paste!{
-
-        #[allow(rustdoc::broken_intra_doc_links)]
-        $( #[ $attr ] )*
-        ///
-        #[doc = data_lense!(maybe_docstring_link $len)]
-        /// bytes long
-        pub fn $field(&self) -> &__ContainerType::Output {
-            &self.0[$offset .. $offset + $len]
-        }
-
-        /// The bytes until the
-        #[doc = data_lense!(maybe_docstring_link Self::$field)]
-        /// field
-        pub fn [< until_ $field >](&self) -> &__ContainerType::Output {
-            &self.0[0 .. $offset]
-        }
-
-        // if the tail exits, consume it as well
-        $(
-        data_lense!{token_muncher_ref @ $offset + $len ; $( $tail )+ }
-        )?
-        }
-    };
-
-    // prefix          @ offset       ; optional meta    ; field name   : field length, ...
-    (token_muncher_mut @ $offset:expr ; $( $attr:meta )* ; $field:ident : $len:expr $(, $( $tail:tt )+ )?) =>  {
-        ::paste::paste!{
-
-        #[allow(rustdoc::broken_intra_doc_links)]
-        $( #[ $attr ] )*
-        ///
-        #[doc = data_lense!(maybe_docstring_link $len)]
-        /// bytes long
-        pub fn [< $field _mut >](&mut self) -> &mut __ContainerType::Output {
-            &mut self.0[$offset .. $offset + $len]
-        }
-
-        // if the tail exits, consume it as well
-        $(
-        data_lense!{token_muncher_mut @ $offset + $len ; $( $tail )+ }
-        )?
-        }
-    };
-
-    // switch that yields literals unchanged, but creates docstring links to
-    // constants
-    // TODO the doc string link doesn't work if $x is taken from a generic,
-    (maybe_docstring_link $x:literal) => (stringify!($x));
-    (maybe_docstring_link $x:expr) => (stringify!([$x]));
-
-    // struct name  < optional generics     >    := optional doc string      field name   : field length, ...
-    ($type:ident $( < $( $generic:ident ),+ > )? := $( $( #[ $attr:meta ] )* $field:ident : $len:expr ),+) => (::paste::paste!{
-
-        #[allow(rustdoc::broken_intra_doc_links)]
-        /// A data lense to manipulate byte slices.
-        ///
-        //// # Fields
-        ///
-        $(
-        /// - `
-        #[doc = stringify!($field)]
-        /// `:
-        #[doc = data_lense!(maybe_docstring_link $len)]
-        /// bytes
-        )+
-        pub struct $type<__ContainerType $(, $( $generic ),+ )? > (
-            __ContainerType,
-            // The phantom data is required, since all generics declared on a
-            // type need to be used on the type.
-            // https://doc.rust-lang.org/stable/error_codes/E0392.html
-            $( $( ::core::marker::PhantomData<$generic> ),+ )?
-        );
-
-        impl<__ContainerType $(, $( $generic: LenseView ),+ )? > $type<__ContainerType $(, $( $generic ),+ )? >{
-            $(
-            pub const fn [< $field _len >]() -> usize{
-                $len
-            }
-            )+
-
-            /// Verify that `len` is sufficiently long to hold [Self]
-            pub fn check_size(len: usize) -> Result<(), RosenpassError>{
-                let required_size = $( $len + )+ 0;
-                let actual_size = len;
-                if required_size != actual_size {
-                    Err(RosenpassError::BufferSizeMismatch {
-                        required_size,
-                        actual_size,
-                    })
-                }else{
-                    Ok(())
-                }
-            }
-        }
-
-        // read-only accessor functions
-        impl<'a, __ContainerType $(, $( $generic: LenseView ),+ )?> $type<&'a __ContainerType $(, $( $generic ),+ )?>
-        where
-            __ContainerType: std::ops::Index<std::ops::Range<usize>> + ?Sized,
-        {
-            data_lense!{token_muncher_ref @ 0 ; $( $( $attr )* ; $field : $len ),+ }
-
-            /// View into all bytes belonging to this Lense
-            pub fn all_bytes(&self) -> &__ContainerType::Output {
-                &self.0[0..Self::LEN]
-            }
-        }
-
-        // mutable accessor functions
-        impl<'a, __ContainerType $(, $( $generic: LenseView ),+ )?> $type<&'a mut __ContainerType $(, $( $generic ),+ )?>
-        where
-            __ContainerType: std::ops::IndexMut<std::ops::Range<usize>> + ?Sized,
-        {
-            data_lense!{token_muncher_ref @ 0 ; $( $( $attr )* ; $field : $len ),+ }
-            data_lense!{token_muncher_mut @ 0 ; $( $( $attr )* ; $field : $len ),+ }
-
-            /// View into all bytes belonging to this Lense
-            pub fn all_bytes(&self) -> &__ContainerType::Output {
-                &self.0[0..Self::LEN]
-            }
-
-            /// View into all bytes belonging to this Lense
-            pub fn all_bytes_mut(&mut self) -> &mut __ContainerType::Output {
-                &mut self.0[0..Self::LEN]
-            }
-        }
-
-        // lense trait, allowing us to know the implementing lenses size
-        impl<__ContainerType $(, $( $generic: LenseView ),+ )? > LenseView for $type<__ContainerType $(, $( $generic ),+ )? >{
-            /// Number of bytes required to store this type in binary format
-            const LEN: usize = $( $len + )+ 0;
-        }
-
-        /// Extension trait to allow checked creation of a lense over
-        /// some byte slice that contains a
-        #[doc = data_lense!(maybe_docstring_link $type)]
-        pub trait [< $type Ext >] {
-            type __ContainerType;
-
-            /// Create a lense to the byte slice
-            fn [< $type:snake >] $(< $($generic : LenseView),* >)? (self) -> Result< $type<Self::__ContainerType, $( $($generic),+ )? >, RosenpassError>;
-
-            /// Create a lense to the byte slice, automatically truncating oversized buffers
-            fn [< $type:snake _ truncating >] $(< $($generic : LenseView),* >)? (self) -> Result< $type<Self::__ContainerType, $( $($generic),+ )? >, RosenpassError>;
-        }
-
-        impl<'a> [< $type Ext >] for &'a [u8] {
-            type __ContainerType = &'a [u8];
-
-            fn [< $type:snake >] $(< $($generic : LenseView),* >)? (self) -> Result< $type<Self::__ContainerType, $( $($generic),+ )? >, RosenpassError> {
-                $type::<Self::__ContainerType, $( $($generic),+ )? >::check_size(self.len())?;
-                Ok($type ( self, $( $( ::core::marker::PhantomData::<$generic>  ),+ )? ))
-            }
-
-            fn [< $type:snake _ truncating >] $(< $($generic : LenseView),* >)? (self) -> Result< $type<Self::__ContainerType, $( $($generic),+ )? >, RosenpassError> {
-                let required_size = $( $len + )+ 0;
-                let actual_size = self.len();
-                if actual_size < required_size {
-                    return Err(RosenpassError::BufferSizeMismatch {
-                        required_size,
-                        actual_size,
-                    });
-                }
-
-                [< $type Ext >]::[< $type:snake >](&self[..required_size])
-            }
-        }
-
-        impl<'a> [< $type Ext >] for &'a mut [u8] {
-            type __ContainerType = &'a mut [u8];
-            fn [< $type:snake >] $(< $($generic : LenseView),* >)? (self) -> Result< $type<Self::__ContainerType, $( $($generic),+ )? >, RosenpassError> {
-                $type::<Self::__ContainerType, $( $($generic),+ )? >::check_size(self.len())?;
-                Ok($type ( self, $( $( ::core::marker::PhantomData::<$generic>  ),+ )? ))
-            }
-
-            fn [< $type:snake _ truncating >] $(< $($generic : LenseView),* >)? (self) -> Result< $type<Self::__ContainerType, $( $($generic),+ )? >, RosenpassError> {
-                let required_size = $( $len + )+ 0;
-                let actual_size = self.len();
-                if actual_size < required_size {
-                    return Err(RosenpassError::BufferSizeMismatch {
-                        required_size,
-                        actual_size,
-                    });
-                }
-
-                [< $type Ext >]::[< $type:snake >](&mut self[..required_size])
-            }
-        }
-    });
-);
-
-/// Common trait shared by all Lenses
-pub trait LenseView {
-    const LEN: usize;
-}
-
-data_lense! { Envelope<M> :=
     /// [MsgType] of this message
     msg_type: 1,
     /// Reserved for future use
@@ -261,40 +61,40 @@ data_lense! { Envelope<M> :=
     payload: M::LEN,
     /// Message Authentication Code (mac) over all bytes until (exclusive)
     /// `mac` itself
-    mac: sodium::MAC_SIZE,
+    mac: 16,
     /// Currently unused, TODO: do something with this
-    cookie: sodium::MAC_SIZE
+    cookie: 16
 }
 
-data_lense! { InitHello :=
+lense! { InitHello :=
     /// Randomly generated connection id
     sidi: 4,
     /// Kyber 512 Ephemeral Public Key
-    epki: EphemeralKEM::PK_LEN,
+    epki: EphemeralKem::PK_LEN,
     /// Classic McEliece Ciphertext
-    sctr: StaticKEM::CT_LEN,
+    sctr: StaticKem::CT_LEN,
     /// Encryped: 16 byte hash of McEliece initiator static key
-    pidic: sodium::AEAD_TAG_LEN + 32,
+    pidic: aead::TAG_LEN + 32,
     /// Encrypted TAI64N Time Stamp (against replay attacks)
-    auth: sodium::AEAD_TAG_LEN
+    auth: aead::TAG_LEN
 }
 
-data_lense! { RespHello :=
+lense! { RespHello :=
     /// Randomly generated connection id
     sidr: 4,
     /// Copied from InitHello
     sidi: 4,
     /// Kyber 512 Ephemeral Ciphertext
-    ecti: EphemeralKEM::CT_LEN,
+    ecti: EphemeralKem::CT_LEN,
     /// Classic McEliece Ciphertext
-    scti: StaticKEM::CT_LEN,
+    scti: StaticKem::CT_LEN,
     /// Empty encrypted message (just an auth tag)
-    auth: sodium::AEAD_TAG_LEN,
+    auth: aead::TAG_LEN,
     /// Responders handshake state in encrypted form
     biscuit: BISCUIT_CT_LEN
 }
 
-data_lense! { InitConf :=
+lense! { InitConf :=
     /// Copied from InitHello
     sidi: 4,
     /// Copied from RespHello
@@ -302,32 +102,32 @@ data_lense! { InitConf :=
     /// Responders handshake state in encrypted form
     biscuit: BISCUIT_CT_LEN,
     /// Empty encrypted message (just an auth tag)
-    auth: sodium::AEAD_TAG_LEN
+    auth: aead::TAG_LEN
 }
 
-data_lense! { EmptyData :=
+lense! { EmptyData :=
     /// Copied from RespHello
     sid: 4,
     /// Nonce
     ctr: 8,
     /// Empty encrypted message (just an auth tag)
-    auth: sodium::AEAD_TAG_LEN
+    auth: aead::TAG_LEN
 }
 
-data_lense! { Biscuit :=
+lense! { Biscuit :=
     /// H(spki) – Ident ifies the initiator
-    pidi: sodium::KEY_SIZE,
+    pidi: KEY_LEN,
     /// The biscuit number (replay protection)
     biscuit_no: 12,
     /// Chaining key
-    ck: sodium::KEY_SIZE
+    ck: KEY_LEN
 }
 
-data_lense! { DataMsg :=
+lense! { DataMsg :=
     dummy: 4
 }
 
-data_lense! { CookieReply :=
+lense! { CookieReply :=
     dummy: 4
 }
 
@@ -381,30 +181,28 @@ impl TryFrom<u8> for MsgType {
 pub const BISCUIT_PT_LEN: usize = Biscuit::<()>::LEN;
 
 /// Length in bytes of an encrypted Biscuit (cipher text)
-pub const BISCUIT_CT_LEN: usize = BISCUIT_PT_LEN + sodium::XAEAD_NONCE_LEN + sodium::XAEAD_TAG_LEN;
+pub const BISCUIT_CT_LEN: usize = BISCUIT_PT_LEN + xaead::NONCE_LEN + xaead::TAG_LEN;
 
 #[cfg(test)]
 mod test_constants {
-    use crate::{
+    use crate::msgs::{BISCUIT_CT_LEN, BISCUIT_PT_LEN};
-        msgs::{BISCUIT_CT_LEN, BISCUIT_PT_LEN},
+    use rosenpass_ciphers::{xaead, KEY_LEN};
-        sodium,
-    };
 
     #[test]
     fn sodium_keysize() {
-        assert_eq!(sodium::KEY_SIZE, 32);
+        assert_eq!(KEY_LEN, 32);
     }
 
     #[test]
     fn biscuit_pt_len() {
-        assert_eq!(BISCUIT_PT_LEN, 2 * sodium::KEY_SIZE + 12);
+        assert_eq!(BISCUIT_PT_LEN, 2 * KEY_LEN + 12);
     }
 
     #[test]
     fn biscuit_ct_len() {
         assert_eq!(
             BISCUIT_CT_LEN,
-            BISCUIT_PT_LEN + sodium::XAEAD_NONCE_LEN + sodium::XAEAD_TAG_LEN
+            BISCUIT_PT_LEN + xaead::NONCE_LEN + xaead::TAG_LEN
         );
     }
 }

rosenpass/src/pqkem.rs

@@ -1,168 +0,0 @@
-//! Traits and implementations for Key Encapsulation Mechanisms (KEMs)
-//!
-//! KEMs are the interface provided by almost all post-quantum
-//! secure key exchange mechanisms.
-//!
-//! Conceptually KEMs are akin to public-key encryption, but instead of encrypting
-//! arbitrary data, KEMs are limited to the transmission of keys, randomly chosen during
-//!
-//! encapsulation.
-//! The [KEM] Trait describes the basic API offered by a Key Encapsulation
-//! Mechanism. Two implementations for it are provided, [StaticKEM] and [EphemeralKEM].
-
-use crate::{RosenpassError, RosenpassMaybeError};
-
-/// Key Encapsulation Mechanism
-///
-/// The KEM interface defines three operations: Key generation, key encapsulation and key
-/// decapsulation.
-pub trait KEM {
-    /// Secrete Key length
-    const SK_LEN: usize;
-    /// Public Key length
-    const PK_LEN: usize;
-    /// Ciphertext length
-    const CT_LEN: usize;
-    /// Shared Secret length
-    const SHK_LEN: usize;
-
-    /// Generate a keypair consisting of secret key (`sk`) and public key (`pk`)
-    ///
-    /// `keygen() -> sk, pk`
-    fn keygen(sk: &mut [u8], pk: &mut [u8]) -> Result<(), RosenpassError>;
-
-    /// From a public key (`pk`), generate a shared key (`shk`, for local use)
-    /// and a cipher text (`ct`, to be sent to the owner of the `pk`).
-    ///
-    /// `encaps(pk) -> shk, ct`
-    fn encaps(shk: &mut [u8], ct: &mut [u8], pk: &[u8]) -> Result<(), RosenpassError>;
-
-    /// From a secret key (`sk`) and a cipher text (`ct`) derive a shared key
-    /// (`shk`)
-    ///
-    /// `decaps(sk, ct) -> shk`
-    fn decaps(shk: &mut [u8], sk: &[u8], ct: &[u8]) -> Result<(), RosenpassError>;
-}
-
-/// A KEM that is secure against Chosen Ciphertext Attacks (CCA).
-/// In the context of rosenpass this is used for static keys.
-/// Uses [Classic McEliece](https://classic.mceliece.org/) 460896 from liboqs.
-///
-/// Classic McEliece is chosen because of its high security margin and its small
-/// ciphertexts. The public keys are humongous, but (being static keys) the are never transmitted over
-/// the wire so this is not a big problem.
-pub struct StaticKEM;
-
-/// # Safety
-///
-/// This Trait impl calls unsafe [oqs_sys] functions, that write to byte
-/// slices only identified using raw pointers. It must be ensured that the raw
-/// pointers point into byte slices of sufficient length, to avoid UB through
-/// overwriting of arbitrary data. This is checked in the following code before
-/// the unsafe calls, and an early return with an Err occurs if the byte slice
-/// size does not match the required size.
-///
-/// __Note__: This requirement is stricter than necessary, it would suffice
-/// to only check that the buffers are big enough, allowing them to be even
-/// bigger. However, from a correctness point of view it does not make sense to
-/// allow bigger buffers.
-impl KEM for StaticKEM {
-    const SK_LEN: usize = oqs_sys::kem::OQS_KEM_classic_mceliece_460896_length_secret_key as usize;
-    const PK_LEN: usize = oqs_sys::kem::OQS_KEM_classic_mceliece_460896_length_public_key as usize;
-    const CT_LEN: usize = oqs_sys::kem::OQS_KEM_classic_mceliece_460896_length_ciphertext as usize;
-    const SHK_LEN: usize =
-        oqs_sys::kem::OQS_KEM_classic_mceliece_460896_length_shared_secret as usize;
-
-    fn keygen(sk: &mut [u8], pk: &mut [u8]) -> Result<(), RosenpassError> {
-        RosenpassError::check_buffer_size(sk.len(), Self::SK_LEN)?;
-        RosenpassError::check_buffer_size(pk.len(), Self::PK_LEN)?;
-        unsafe {
-            oqs_sys::kem::OQS_KEM_classic_mceliece_460896_keypair(pk.as_mut_ptr(), sk.as_mut_ptr())
-                .to_rg_error()
-        }
-    }
-
-    fn encaps(shk: &mut [u8], ct: &mut [u8], pk: &[u8]) -> Result<(), RosenpassError> {
-        RosenpassError::check_buffer_size(shk.len(), Self::SHK_LEN)?;
-        RosenpassError::check_buffer_size(ct.len(), Self::CT_LEN)?;
-        RosenpassError::check_buffer_size(pk.len(), Self::PK_LEN)?;
-        unsafe {
-            oqs_sys::kem::OQS_KEM_classic_mceliece_460896_encaps(
-                ct.as_mut_ptr(),
-                shk.as_mut_ptr(),
-                pk.as_ptr(),
-            )
-            .to_rg_error()
-        }
-    }
-
-    fn decaps(shk: &mut [u8], sk: &[u8], ct: &[u8]) -> Result<(), RosenpassError> {
-        RosenpassError::check_buffer_size(shk.len(), Self::SHK_LEN)?;
-        RosenpassError::check_buffer_size(sk.len(), Self::SK_LEN)?;
-        RosenpassError::check_buffer_size(ct.len(), Self::CT_LEN)?;
-        unsafe {
-            oqs_sys::kem::OQS_KEM_classic_mceliece_460896_decaps(
-                shk.as_mut_ptr(),
-                ct.as_ptr(),
-                sk.as_ptr(),
-            )
-            .to_rg_error()
-        }
-    }
-}
-
-/// Implements a KEM that is secure against Chosen Plaintext Attacks (CPA).
-/// In the context of rosenpass this is used for ephemeral keys.
-/// Currently the implementation uses
-/// [Kyber 512](https://openquantumsafe.org/liboqs/algorithms/kem/kyber) from liboqs.
-///
-/// This is being used for ephemeral keys; since these are use-once the first post quantum
-/// wireguard paper claimed that CPA security would be sufficient. Nonetheless we choose kyber
-/// which provides CCA security since there are no publicly vetted KEMs out there which provide
-/// only CPA security.
-pub struct EphemeralKEM;
-
-/// # Safety
-///
-/// This Trait impl calls unsafe [oqs_sys] functions, that write to byte
-/// slices only identified using raw pointers. It must be ensured that the raw
-/// pointers point into byte slices of sufficient length, to avoid UB through
-/// overwriting of arbitrary data. This is checked in the following code before
-/// the unsafe calls, and an early return with an Err occurs if the byte slice
-/// size does not match the required size.
-///
-/// __Note__: This requirement is stricter than necessary, it would suffice
-/// to only check that the buffers are big enough, allowing them to be even
-/// bigger. However, from a correctness point of view it does not make sense to
-/// allow bigger buffers.
-impl KEM for EphemeralKEM {
-    const SK_LEN: usize = oqs_sys::kem::OQS_KEM_kyber_512_length_secret_key as usize;
-    const PK_LEN: usize = oqs_sys::kem::OQS_KEM_kyber_512_length_public_key as usize;
-    const CT_LEN: usize = oqs_sys::kem::OQS_KEM_kyber_512_length_ciphertext as usize;
-    const SHK_LEN: usize = oqs_sys::kem::OQS_KEM_kyber_512_length_shared_secret as usize;
-    fn keygen(sk: &mut [u8], pk: &mut [u8]) -> Result<(), RosenpassError> {
-        RosenpassError::check_buffer_size(sk.len(), Self::SK_LEN)?;
-        RosenpassError::check_buffer_size(pk.len(), Self::PK_LEN)?;
-        unsafe {
-            oqs_sys::kem::OQS_KEM_kyber_512_keypair(pk.as_mut_ptr(), sk.as_mut_ptr()).to_rg_error()
-        }
-    }
-    fn encaps(shk: &mut [u8], ct: &mut [u8], pk: &[u8]) -> Result<(), RosenpassError> {
-        RosenpassError::check_buffer_size(shk.len(), Self::SHK_LEN)?;
-        RosenpassError::check_buffer_size(ct.len(), Self::CT_LEN)?;
-        RosenpassError::check_buffer_size(pk.len(), Self::PK_LEN)?;
-        unsafe {
-            oqs_sys::kem::OQS_KEM_kyber_512_encaps(ct.as_mut_ptr(), shk.as_mut_ptr(), pk.as_ptr())
-                .to_rg_error()
-        }
-    }
-    fn decaps(shk: &mut [u8], sk: &[u8], ct: &[u8]) -> Result<(), RosenpassError> {
-        RosenpassError::check_buffer_size(shk.len(), Self::SHK_LEN)?;
-        RosenpassError::check_buffer_size(sk.len(), Self::SK_LEN)?;
-        RosenpassError::check_buffer_size(ct.len(), Self::CT_LEN)?;
-        unsafe {
-            oqs_sys::kem::OQS_KEM_kyber_512_decaps(shk.as_mut_ptr(), ct.as_ptr(), sk.as_ptr())
-                .to_rg_error()
-        }
-    }
-}

rosenpass/src/prftree.rs

@@ -1,108 +0,0 @@
-//! Implementation of the tree-like structure used for the label derivation in [labeled_prf](crate::labeled_prf)
-use {
-    crate::{
-        coloring::Secret,
-        sodium::{hmac, hmac_into, KEY_SIZE},
-    },
-    anyhow::Result,
-};
-
-// TODO Use a proper Dec interface
-#[derive(Clone, Debug)]
-pub struct PrfTree([u8; KEY_SIZE]);
-#[derive(Clone, Debug)]
-pub struct PrfTreeBranch([u8; KEY_SIZE]);
-#[derive(Clone, Debug)]
-pub struct SecretPrfTree(Secret<KEY_SIZE>);
-#[derive(Clone, Debug)]
-pub struct SecretPrfTreeBranch(Secret<KEY_SIZE>);
-
-impl PrfTree {
-    pub fn zero() -> Self {
-        Self([0u8; KEY_SIZE])
-    }
-
-    pub fn dup(self) -> PrfTreeBranch {
-        PrfTreeBranch(self.0)
-    }
-
-    pub fn into_secret_prf_tree(self) -> SecretPrfTree {
-        SecretPrfTree(Secret::from_slice(&self.0))
-    }
-
-    // TODO: Protocol! Use domain separation to ensure that
-    pub fn mix(self, v: &[u8]) -> Result<Self> {
-        Ok(Self(hmac(&self.0, v)?))
-    }
-
-    pub fn mix_secret<const N: usize>(self, v: Secret<N>) -> Result<SecretPrfTree> {
-        SecretPrfTree::prf_invoc(&self.0, v.secret())
-    }
-
-    pub fn into_value(self) -> [u8; KEY_SIZE] {
-        self.0
-    }
-}
-
-impl PrfTreeBranch {
-    pub fn mix(&self, v: &[u8]) -> Result<PrfTree> {
-        Ok(PrfTree(hmac(&self.0, v)?))
-    }
-
-    pub fn mix_secret<const N: usize>(&self, v: Secret<N>) -> Result<SecretPrfTree> {
-        SecretPrfTree::prf_invoc(&self.0, v.secret())
-    }
-}
-
-impl SecretPrfTree {
-    pub fn prf_invoc(k: &[u8], d: &[u8]) -> Result<SecretPrfTree> {
-        let mut r = SecretPrfTree(Secret::zero());
-        hmac_into(r.0.secret_mut(), k, d)?;
-        Ok(r)
-    }
-
-    pub fn zero() -> Self {
-        Self(Secret::zero())
-    }
-
-    pub fn dup(self) -> SecretPrfTreeBranch {
-        SecretPrfTreeBranch(self.0)
-    }
-
-    pub fn danger_from_secret(k: Secret<KEY_SIZE>) -> Self {
-        Self(k)
-    }
-
-    pub fn mix(self, v: &[u8]) -> Result<SecretPrfTree> {
-        Self::prf_invoc(self.0.secret(), v)
-    }
-
-    pub fn mix_secret<const N: usize>(self, v: Secret<N>) -> Result<SecretPrfTree> {
-        Self::prf_invoc(self.0.secret(), v.secret())
-    }
-
-    pub fn into_secret(self) -> Secret<KEY_SIZE> {
-        self.0
-    }
-
-    pub fn into_secret_slice(mut self, v: &[u8], dst: &[u8]) -> Result<()> {
-        hmac_into(self.0.secret_mut(), v, dst)
-    }
-}
-
-impl SecretPrfTreeBranch {
-    pub fn mix(&self, v: &[u8]) -> Result<SecretPrfTree> {
-        SecretPrfTree::prf_invoc(self.0.secret(), v)
-    }
-
-    pub fn mix_secret<const N: usize>(&self, v: Secret<N>) -> Result<SecretPrfTree> {
-        SecretPrfTree::prf_invoc(self.0.secret(), v.secret())
-    }
-
-    // TODO: This entire API is not very nice; we need this for biscuits, but
-    // it might be better to extract a special "biscuit"
-    // labeled subkey and reinitialize the chain with this
-    pub fn danger_into_secret(self) -> Secret<KEY_SIZE> {
-        self.0
-    }
-}

rosenpass/src/protocol.rs

@@ -19,22 +19,20 @@
 //! [CryptoServer].
 //!
 //! ```
+//! use rosenpass_cipher_traits::Kem;
+//! use rosenpass_ciphers::kem::StaticKem;
 //! use rosenpass::{
-//!     pqkem::{StaticKEM, KEM},
 //!     protocol::{SSk, SPk, MsgBuf, PeerPtr, CryptoServer, SymKey},
 //! };
 //! # fn main() -> anyhow::Result<()> {
 //!
-//! // always init libsodium before anything
-//! rosenpass::sodium::sodium_init()?;
-//!
 //! // initialize secret and public key for peer a ...
 //! let (mut peer_a_sk, mut peer_a_pk) = (SSk::zero(), SPk::zero());
-//! StaticKEM::keygen(peer_a_sk.secret_mut(), peer_a_pk.secret_mut())?;
+//! StaticKem::keygen(peer_a_sk.secret_mut(), peer_a_pk.secret_mut())?;
 //!
 //! // ... and for peer b
 //! let (mut peer_b_sk, mut peer_b_pk) = (SSk::zero(), SPk::zero());
-//! StaticKEM::keygen(peer_b_sk.secret_mut(), peer_b_pk.secret_mut())?;
+//! StaticKem::keygen(peer_b_sk.secret_mut(), peer_b_pk.secret_mut())?;
 //!
 //! // initialize server and a pre-shared key
 //! let psk = SymKey::random();
@@ -67,20 +65,24 @@
 //! # }
 //! ```
 
-use crate::{
-    coloring::*,
-    labeled_prf as lprf,
-    msgs::*,
-    pqkem::*,
-    prftree::{SecretPrfTree, SecretPrfTreeBranch},
-    sodium::*,
-    util::*,
-};
-use anyhow::{bail, ensure, Context, Result};
 use std::collections::hash_map::{
     Entry::{Occupied, Vacant},
     HashMap,
 };
+use std::convert::Infallible;
+
+use anyhow::{bail, ensure, Context, Result};
+
+use rosenpass_cipher_traits::Kem;
+use rosenpass_ciphers::hash_domain::{SecretHashDomain, SecretHashDomainNamespace};
+use rosenpass_ciphers::kem::{EphemeralKem, StaticKem};
+use rosenpass_ciphers::{aead, xaead, KEY_LEN};
+use rosenpass_constant_time as constant_time;
+use rosenpass_lenses::LenseView;
+use rosenpass_secret_memory::{Public, Secret};
+use rosenpass_util::{cat, mem::cpy_min, ord::max_usize, time::Timebase};
+
+use crate::{hash_domains, msgs::*};
 
 // CONSTANTS & SETTINGS //////////////////////////
 
@@ -139,19 +141,19 @@ pub fn has_happened(ev: Timing, now: Timing) -> bool {
 
 // DATA STRUCTURES & BASIC TRAITS & ACCESSORS ////
 
-pub type SPk = Secret<{ StaticKEM::PK_LEN }>; // Just Secret<> instead of Public<> so it gets allocated on the heap
+pub type SPk = Secret<{ StaticKem::PK_LEN }>; // Just Secret<> instead of Public<> so it gets allocated on the heap
-pub type SSk = Secret<{ StaticKEM::SK_LEN }>;
+pub type SSk = Secret<{ StaticKem::SK_LEN }>;
-pub type EPk = Public<{ EphemeralKEM::PK_LEN }>;
+pub type EPk = Public<{ EphemeralKem::PK_LEN }>;
-pub type ESk = Secret<{ EphemeralKEM::SK_LEN }>;
+pub type ESk = Secret<{ EphemeralKem::SK_LEN }>;
 
-pub type SymKey = Secret<KEY_SIZE>;
+pub type SymKey = Secret<KEY_LEN>;
-pub type SymHash = Public<KEY_SIZE>;
+pub type SymHash = Public<KEY_LEN>;
 
-pub type PeerId = Public<KEY_SIZE>;
+pub type PeerId = Public<KEY_LEN>;
 pub type SessionId = Public<SESSION_ID_LEN>;
 pub type BiscuitId = Public<BISCUIT_ID_LEN>;
 
-pub type XAEADNonce = Public<XAEAD_NONCE_LEN>;
+pub type XAEADNonce = Public<{ xaead::NONCE_LEN }>;
 
 pub type MsgBuf = Public<MAX_MESSAGE_LEN>;
 
@@ -233,7 +235,7 @@ pub struct HandshakeState {
     /// Session ID of Responder
     pub sidr: SessionId,
     /// Chaining Key
-    pub ck: SecretPrfTreeBranch,
+    pub ck: SecretHashDomainNamespace, // TODO: We should probably add an abstr
 }
 
 #[derive(Hash, PartialEq, Eq, PartialOrd, Ord, Debug, Copy, Clone)]
@@ -285,7 +287,7 @@ pub struct Session {
     pub sidt: SessionId,
     pub handshake_role: HandshakeRole,
     // Crypto
-    pub ck: SecretPrfTreeBranch,
+    pub ck: SecretHashDomainNamespace,
     /// Key for Transmission ("transmission key mine")
     pub txkm: SymKey,
     /// Key for Reception ("transmission key theirs")
@@ -460,7 +462,7 @@ impl CryptoServer {
     #[rustfmt::skip]
     pub fn pidm(&self) -> Result<PeerId> {
         Ok(Public::new(
-            lprf::peerid()?
+            hash_domains::peerid()?
                 .mix(self.spkm.secret())?
                 .into_value()))
     }
@@ -590,7 +592,7 @@ impl Peer {
     #[rustfmt::skip]
     pub fn pidt(&self) -> Result<PeerId> {
         Ok(Public::new(
-            lprf::peerid()?
+            hash_domains::peerid()?
                 .mix(self.spkt.secret())?
                 .into_value()))
     }
@@ -603,7 +605,7 @@ impl Session {
             sidm: SessionId::zero(),
             sidt: SessionId::zero(),
             handshake_role: HandshakeRole::Initiator,
-            ck: SecretPrfTree::zero().dup(),
+            ck: SecretHashDomain::zero().dup(),
             txkm: SymKey::zero(),
             txkt: SymKey::zero(),
             txnm: 0,
@@ -822,12 +824,12 @@ impl CryptoServer {
                 ensure!(msg_in.check_seal(self)?, seal_broken);
 
                 let mut msg_out = tx_buf.envelope_truncating::<EmptyData<&mut [u8]>>()?;
-                let (peer, if_exchanged) = self.handle_init_conf(
+                let peer = self.handle_init_conf(
                     msg_in.payload().init_conf()?,
                     msg_out.payload_mut().empty_data()?,
                 )?;
                 len = self.seal_and_commit_msg(peer, MsgType::EmptyData, msg_out)?;
-                exchanged = if_exchanged;
+                exchanged = true;
                 peer
             }
             Ok(MsgType::EmptyData) => {
@@ -1154,7 +1156,7 @@ impl IniHsPtr {
                         .min(ih.tx_count as f64),
                 )
                 * RETRANSMIT_DELAY_JITTER
-                * (rand_f64() + 1.0);
+                * (rand::random::<f64>() + 1.0); // TODO: Replace with the rand crate
         ih.tx_count += 1;
         Ok(())
     }
@@ -1174,7 +1176,7 @@ where
 {
     /// Calculate the message authentication code (`mac`)
     pub fn seal(&mut self, peer: PeerPtr, srv: &CryptoServer) -> Result<()> {
-        let mac = lprf::mac()?
+        let mac = hash_domains::mac()?
             .mix(peer.get(srv).spkt.secret())?
             .mix(self.until_mac())?;
         self.mac_mut()
@@ -1189,8 +1191,13 @@ where
 {
     /// Check the message authentication code
     pub fn check_seal(&self, srv: &CryptoServer) -> Result<bool> {
-        let expected = lprf::mac()?.mix(srv.spkm.secret())?.mix(self.until_mac())?;
+        let expected = hash_domains::mac()?
-        Ok(sodium_memcmp(self.mac(), &expected.into_value()[..16]))
+            .mix(srv.spkm.secret())?
+            .mix(self.until_mac())?;
+        Ok(constant_time::memcmp(
+            self.mac(),
+            &expected.into_value()[..16],
+        ))
     }
 }
 
@@ -1216,38 +1223,38 @@ impl HandshakeState {
         Self {
             sidi: SessionId::zero(),
             sidr: SessionId::zero(),
-            ck: SecretPrfTree::zero().dup(),
+            ck: SecretHashDomain::zero().dup(),
         }
     }
 
     pub fn erase(&mut self) {
-        self.ck = SecretPrfTree::zero().dup();
+        self.ck = SecretHashDomain::zero().dup();
     }
 
     pub fn init(&mut self, spkr: &[u8]) -> Result<&mut Self> {
-        self.ck = lprf::ckinit()?.mix(spkr)?.into_secret_prf_tree().dup();
+        self.ck = hash_domains::ckinit()?.turn_secret().mix(spkr)?.dup();
         Ok(self)
     }
 
     pub fn mix(&mut self, a: &[u8]) -> Result<&mut Self> {
-        self.ck = self.ck.mix(&lprf::mix()?)?.mix(a)?.dup();
+        self.ck = self.ck.mix(&hash_domains::mix()?)?.mix(a)?.dup();
         Ok(self)
     }
 
     pub fn encrypt_and_mix(&mut self, ct: &mut [u8], pt: &[u8]) -> Result<&mut Self> {
-        let k = self.ck.mix(&lprf::hs_enc()?)?.into_secret();
+        let k = self.ck.mix(&hash_domains::hs_enc()?)?.into_secret();
-        aead_enc_into(ct, k.secret(), &NONCE0, &NOTHING, pt)?;
+        aead::encrypt(ct, k.secret(), &[0u8; aead::NONCE_LEN], &[], pt)?;
         self.mix(ct)
     }
 
     pub fn decrypt_and_mix(&mut self, pt: &mut [u8], ct: &[u8]) -> Result<&mut Self> {
-        let k = self.ck.mix(&lprf::hs_enc()?)?.into_secret();
+        let k = self.ck.mix(&hash_domains::hs_enc()?)?.into_secret();
-        aead_dec_into(pt, k.secret(), &NONCE0, &NOTHING, ct)?;
+        aead::decrypt(pt, k.secret(), &[0u8; aead::NONCE_LEN], &[], ct)?;
         self.mix(ct)
     }
 
     // I loathe "error: constant expression depends on a generic parameter"
-    pub fn encaps_and_mix<T: KEM, const SHK_LEN: usize>(
+    pub fn encaps_and_mix<T: Kem<Error = Infallible>, const SHK_LEN: usize>(
         &mut self,
         ct: &mut [u8],
         pk: &[u8],
@@ -1257,7 +1264,7 @@ impl HandshakeState {
         self.mix(pk)?.mix(shk.secret())?.mix(ct)
     }
 
-    pub fn decaps_and_mix<T: KEM, const SHK_LEN: usize>(
+    pub fn decaps_and_mix<T: Kem<Error = Infallible>, const SHK_LEN: usize>(
         &mut self,
         sk: &[u8],
         pk: &[u8],
@@ -1287,14 +1294,14 @@ impl HandshakeState {
             .copy_from_slice(self.ck.clone().danger_into_secret().secret());
 
         // calculate ad contents
-        let ad = lprf::biscuit_ad()?
+        let ad = hash_domains::biscuit_ad()?
             .mix(srv.spkm.secret())?
             .mix(self.sidi.as_slice())?
             .mix(self.sidr.as_slice())?
             .into_value();
 
         // consume biscuit no
-        sodium_bigint_inc(&mut *srv.biscuit_ctr);
+        constant_time::increment(&mut *srv.biscuit_ctr);
 
         // The first bit of the nonce indicates which biscuit key was used
         // TODO: This is premature optimization. Remove!
@@ -1305,7 +1312,7 @@ impl HandshakeState {
 
         let k = bk.get(srv).key.secret();
         let pt = biscuit.all_bytes();
-        xaead_enc_into(biscuit_ct, k, &*n, &ad, pt)?;
+        xaead::encrypt(biscuit_ct, k, &*n, &ad, pt)?;
 
         self.mix(biscuit_ct)
     }
@@ -1322,7 +1329,7 @@ impl HandshakeState {
         let bk = BiscuitKeyPtr(((biscuit_ct[0] & 0b1000_0000) >> 7) as usize);
 
         // Calculate additional data fields
-        let ad = lprf::biscuit_ad()?
+        let ad = hash_domains::biscuit_ad()?
             .mix(srv.spkm.secret())?
             .mix(sidi.as_slice())?
             .mix(sidr.as_slice())?
@@ -1331,7 +1338,7 @@ impl HandshakeState {
         // Allocate and decrypt the biscuit data
         let mut biscuit = Secret::<BISCUIT_PT_LEN>::zero(); // pt buf
         let mut biscuit = (&mut biscuit.secret_mut()[..]).biscuit()?; // slice
-        xaead_dec_into(
+        xaead::decrypt(
             biscuit.all_bytes_mut(),
             bk.get(srv).key.secret(),
             &ad,
@@ -1340,7 +1347,7 @@ impl HandshakeState {
 
         // Reconstruct the biscuit fields
         let no = BiscuitId::from_slice(biscuit.biscuit_no());
-        let ck = SecretPrfTree::danger_from_secret(Secret::from_slice(biscuit.ck())).dup();
+        let ck = SecretHashDomain::danger_from_secret(Secret::from_slice(biscuit.ck())).dup();
         let pid = PeerId::from_slice(biscuit.pidi());
 
         // Reconstruct the handshake state
@@ -1357,7 +1364,7 @@ impl HandshakeState {
         // indicates retransmission
         // TODO: Handle retransmissions without involving the crypto code
         ensure!(
-            sodium_bigint_cmp(biscuit.biscuit_no(), &*peer.get(srv).biscuit_used) >= 0,
+            constant_time::compare(biscuit.biscuit_no(), &*peer.get(srv).biscuit_used) >= 0,
             "Rejecting biscuit: Outdated biscuit number"
         );
 
@@ -1366,8 +1373,8 @@ impl HandshakeState {
 
     pub fn enter_live(self, srv: &CryptoServer, role: HandshakeRole) -> Result<Session> {
         let HandshakeState { ck, sidi, sidr } = self;
-        let tki = ck.mix(&lprf::ini_enc()?)?.into_secret();
+        let tki = ck.mix(&hash_domains::ini_enc()?)?.into_secret();
-        let tkr = ck.mix(&lprf::res_enc()?)?.into_secret();
+        let tkr = ck.mix(&hash_domains::res_enc()?)?.into_secret();
         let created_at = srv.timebase.now();
         let (ntx, nrx) = (0, 0);
         let (mysid, peersid, ktx, krx) = match role {
@@ -1398,7 +1405,7 @@ impl CryptoServer {
             .get(self)
             .as_ref()
             .with_context(|| format!("No current session for peer {:?}", peer))?;
-        Ok(session.ck.mix(&lprf::osk()?)?.into_secret())
+        Ok(session.ck.mix(&hash_domains::osk()?)?.into_secret())
     }
 }
 
@@ -1420,7 +1427,7 @@ impl CryptoServer {
         ih.sidi_mut().copy_from_slice(&hs.core.sidi.value);
 
         // IHI3
-        EphemeralKEM::keygen(hs.eski.secret_mut(), &mut *hs.epki)?;
+        EphemeralKem::keygen(hs.eski.secret_mut(), &mut *hs.epki)?;
         ih.epki_mut().copy_from_slice(&hs.epki.value);
 
         // IHI4
@@ -1428,7 +1435,7 @@ impl CryptoServer {
 
         // IHI5
         hs.core
-            .encaps_and_mix::<StaticKEM, { StaticKEM::SHK_LEN }>(
+            .encaps_and_mix::<StaticKem, { StaticKem::SHK_LEN }>(
                 ih.sctr_mut(),
                 peer.get(self).spkt.secret(),
             )?;
@@ -1443,7 +1450,7 @@ impl CryptoServer {
             .mix(peer.get(self).psk.secret())?;
 
         // IHI8
-        hs.core.encrypt_and_mix(ih.auth_mut(), &NOTHING)?;
+        hs.core.encrypt_and_mix(ih.auth_mut(), &[])?;
 
         // Update the handshake hash last (not changing any state on prior error
         peer.hs().insert(self, hs)?;
@@ -1467,7 +1474,7 @@ impl CryptoServer {
         core.mix(ih.sidi())?.mix(ih.epki())?;
 
         // IHR5
-        core.decaps_and_mix::<StaticKEM, { StaticKEM::SHK_LEN }>(
+        core.decaps_and_mix::<StaticKem, { StaticKem::SHK_LEN }>(
             self.sskm.secret(),
             self.spkm.secret(),
             ih.sctr(),
@@ -1497,10 +1504,10 @@ impl CryptoServer {
         core.mix(rh.sidr())?.mix(rh.sidi())?;
 
         // RHR4
-        core.encaps_and_mix::<EphemeralKEM, { EphemeralKEM::SHK_LEN }>(rh.ecti_mut(), ih.epki())?;
+        core.encaps_and_mix::<EphemeralKem, { EphemeralKem::SHK_LEN }>(rh.ecti_mut(), ih.epki())?;
 
         // RHR5
-        core.encaps_and_mix::<StaticKEM, { StaticKEM::SHK_LEN }>(
+        core.encaps_and_mix::<StaticKem, { StaticKem::SHK_LEN }>(
             rh.scti_mut(),
             peer.get(self).spkt.secret(),
         )?;
@@ -1509,7 +1516,7 @@ impl CryptoServer {
         core.store_biscuit(self, peer, rh.biscuit_mut())?;
 
         // RHR7
-        core.encrypt_and_mix(rh.auth_mut(), &NOTHING)?;
+        core.encrypt_and_mix(rh.auth_mut(), &[])?;
 
         Ok(peer)
     }
@@ -1565,14 +1572,14 @@ impl CryptoServer {
         core.mix(rh.sidr())?.mix(rh.sidi())?;
 
         // RHI4
-        core.decaps_and_mix::<EphemeralKEM, { EphemeralKEM::SHK_LEN }>(
+        core.decaps_and_mix::<EphemeralKem, { EphemeralKem::SHK_LEN }>(
             hs!().eski.secret(),
             &*hs!().epki,
             rh.ecti(),
         )?;
 
         // RHI5
-        core.decaps_and_mix::<StaticKEM, { StaticKEM::SHK_LEN }>(
+        core.decaps_and_mix::<StaticKem, { StaticKem::SHK_LEN }>(
             self.sskm.secret(),
             self.spkm.secret(),
             rh.scti(),
@@ -1595,7 +1602,7 @@ impl CryptoServer {
         ic.biscuit_mut().copy_from_slice(rh.biscuit());
 
         // ICI4
-        core.encrypt_and_mix(ic.auth_mut(), &NOTHING)?;
+        core.encrypt_and_mix(ic.auth_mut(), &[])?;
 
         // Split() – We move the secrets into the session; we do not
         // delete the InitiatorHandshake, just clear it's secrets because
@@ -1614,8 +1621,7 @@ impl CryptoServer {
         &mut self,
         ic: InitConf<&[u8]>,
         mut rc: EmptyData<&mut [u8]>,
-    ) -> Result<(PeerPtr, bool)> {
+    ) -> Result<PeerPtr> {
-        let mut exchanged = false;
         // (peer, bn) ← LoadBiscuit(InitConf.biscuit)
         // ICR1
         let (peer, biscuit_no, mut core) = HandshakeState::load_biscuit(
@@ -1626,7 +1632,7 @@ impl CryptoServer {
         )?;
 
         // ICR2
-        core.encrypt_and_mix(&mut [0u8; AEAD_TAG_LEN], &NOTHING)?;
+        core.encrypt_and_mix(&mut [0u8; aead::TAG_LEN], &[])?;
 
         // ICR3
         core.mix(ic.sidi())?.mix(ic.sidr())?;
@@ -1635,7 +1641,7 @@ impl CryptoServer {
         core.decrypt_and_mix(&mut [0u8; 0], ic.auth())?;
 
         // ICR5
-        if sodium_bigint_cmp(&*biscuit_no, &*peer.get(self).biscuit_used) > 0 {
+        if constant_time::compare(&*biscuit_no, &*peer.get(self).biscuit_used) > 0 {
             // ICR6
             peer.get_mut(self).biscuit_used = biscuit_no;
 
@@ -1645,9 +1651,6 @@ impl CryptoServer {
             // TODO: This should be part of the protocol specification.
             // Abort any ongoing handshake from initiator role
             peer.hs().take(self);
-
-            // Only exchange key on a new biscuit number
-            exchanged = true;
         }
 
         // TODO: Implementing RP should be possible without touching the live session stuff
@@ -1683,11 +1686,11 @@ impl CryptoServer {
         rc.ctr_mut().copy_from_slice(&ses.txnm.to_le_bytes());
         ses.txnm += 1; // Increment nonce before encryption, just in case an error is raised
 
-        let n = cat!(AEAD_NONCE_LEN; rc.ctr(), &[0u8; 4]);
+        let n = cat!(aead::NONCE_LEN; rc.ctr(), &[0u8; 4]);
         let k = ses.txkm.secret();
-        aead_enc_into(rc.auth_mut(), k, &n, &NOTHING, &NOTHING)?; // ct, k, n, ad, pt
+        aead::encrypt(rc.auth_mut(), k, &n, &[], &[])?; // ct, k, n, ad, pt
 
-        Ok((peer, exchanged))
+        Ok(peer)
     }
 
     pub fn handle_resp_conf(&mut self, rc: EmptyData<&[u8]>) -> Result<PeerPtr> {
@@ -1717,12 +1720,12 @@ impl CryptoServer {
             let n = u64::from_le_bytes(rc.ctr().try_into().unwrap());
             ensure!(n >= s.txnt, "Stale nonce");
             s.txnt = n;
-            aead_dec_into(
+            aead::decrypt(
                 // pt, k, n, ad, ct
                 &mut [0u8; 0],
                 s.txkt.secret(),
-                &cat!(AEAD_NONCE_LEN; rc.ctr(), &[0u8; 4]),
+                &cat!(aead::NONCE_LEN; rc.ctr(), &[0u8; 4]),
-                &NOTHING,
+                &[],
                 rc.auth(),
             )?;
         }
@@ -1754,8 +1757,6 @@ mod test {
     /// Through all this, the handshake should still successfully terminate;
     /// i.e. an exchanged key must be produced in both servers.
     fn handles_incorrect_size_messages() {
-        crate::sodium::sodium_init().unwrap();
-
         stacker::grow(8 * 1024 * 1024, || {
             const OVERSIZED_MESSAGE: usize = ((MAX_MESSAGE_LEN as f32) * 1.2) as usize;
             type MsgBufPlus = Public<OVERSIZED_MESSAGE>;
@@ -1767,14 +1768,10 @@ mod test {
 
             // Process the entire handshake
             let mut msglen = Some(me.initiate_handshake(PEER0, &mut *resbuf).unwrap());
-            loop {
+            while let Some(l) = msglen {
-                if let Some(l) = msglen {
+                std::mem::swap(&mut me, &mut they);
-                    std::mem::swap(&mut me, &mut they);
+                std::mem::swap(&mut msgbuf, &mut resbuf);
-                    std::mem::swap(&mut msgbuf, &mut resbuf);
+                msglen = test_incorrect_sizes_for_msg(&mut me, &*msgbuf, l, &mut *resbuf);
-                    msglen = test_incorrect_sizes_for_msg(&mut me, &*msgbuf, l, &mut *resbuf);
-                } else {
-                    break;
-                }
             }
 
             assert_eq!(
@@ -1801,8 +1798,8 @@ mod test {
             }
 
             let res = srv.handle_msg(&msgbuf[..l], resbuf);
-            assert!(matches!(res, Err(_))); // handle_msg should raise an error
+            assert!(res.is_err()); // handle_msg should raise an error
-            assert!(!resbuf.iter().find(|x| **x != 0).is_some()); // resbuf should not have been changed
+            assert!(!resbuf.iter().any(|x| *x != 0)); // resbuf should not have been changed
         }
 
         // Apply the proper handle_msg operation
@@ -1812,7 +1809,7 @@ mod test {
     fn keygen() -> Result<(SSk, SPk)> {
         // TODO: Copied from the benchmark; deduplicate
         let (mut sk, mut pk) = (SSk::zero(), SPk::zero());
-        StaticKEM::keygen(sk.secret_mut(), pk.secret_mut())?;
+        StaticKem::keygen(sk.secret_mut(), pk.secret_mut())?;
         Ok((sk, pk))
     }
 

rosenpass/src/sodium.rs

@@ -1,285 +0,0 @@
-//! Bindings and helpers for accessing libsodium functions
-
-use crate::util::*;
-use anyhow::{ensure, Result};
-use libsodium_sys as libsodium;
-use log::trace;
-use static_assertions::const_assert_eq;
-use std::os::raw::{c_ulonglong, c_void};
-use std::ptr::{null as nullptr, null_mut as nullptr_mut};
-
-pub const AEAD_TAG_LEN: usize = libsodium::crypto_aead_chacha20poly1305_IETF_ABYTES as usize;
-pub const AEAD_NONCE_LEN: usize = libsodium::crypto_aead_chacha20poly1305_IETF_NPUBBYTES as usize;
-pub const XAEAD_TAG_LEN: usize = libsodium::crypto_aead_xchacha20poly1305_ietf_ABYTES as usize;
-pub const XAEAD_NONCE_LEN: usize = libsodium::crypto_aead_xchacha20poly1305_IETF_NPUBBYTES as usize;
-pub const NONCE0: [u8; libsodium::crypto_aead_chacha20poly1305_IETF_NPUBBYTES as usize] =
-    [0u8; libsodium::crypto_aead_chacha20poly1305_IETF_NPUBBYTES as usize];
-pub const NOTHING: [u8; 0] = [0u8; 0];
-pub const KEY_SIZE: usize = 32;
-pub const MAC_SIZE: usize = 16;
-
-const_assert_eq!(
-    KEY_SIZE,
-    libsodium::crypto_aead_chacha20poly1305_IETF_KEYBYTES as usize
-);
-const_assert_eq!(KEY_SIZE, libsodium::crypto_generichash_BYTES as usize);
-
-macro_rules! sodium_call {
-    ($name:ident, $($args:expr),*) => { attempt!({
-        ensure!(unsafe{libsodium::$name($($args),*)} > -1,
-            "Error in libsodium's {}.", stringify!($name));
-        Ok(())
-    })};
-    ($name:ident) => { sodium_call!($name, ) };
-}
-
-#[inline]
-pub fn sodium_init() -> Result<()> {
-    trace!("initializing libsodium");
-    sodium_call!(sodium_init)
-}
-
-#[inline]
-pub fn sodium_memcmp(a: &[u8], b: &[u8]) -> bool {
-    a.len() == b.len()
-        && unsafe {
-            let r = libsodium::sodium_memcmp(
-                a.as_ptr() as *const c_void,
-                b.as_ptr() as *const c_void,
-                a.len(),
-            );
-            r == 0
-        }
-}
-
-#[inline]
-pub fn sodium_bigint_cmp(a: &[u8], b: &[u8]) -> i32 {
-    assert!(a.len() == b.len());
-    unsafe { libsodium::sodium_compare(a.as_ptr(), b.as_ptr(), a.len()) }
-}
-
-#[inline]
-pub fn sodium_bigint_inc(v: &mut [u8]) {
-    unsafe {
-        libsodium::sodium_increment(v.as_mut_ptr(), v.len());
-    }
-}
-
-#[inline]
-pub fn rng(buf: &mut [u8]) {
-    unsafe { libsodium::randombytes_buf(buf.as_mut_ptr() as *mut c_void, buf.len()) };
-}
-
-#[inline]
-pub fn zeroize(buf: &mut [u8]) {
-    unsafe { libsodium::sodium_memzero(buf.as_mut_ptr() as *mut c_void, buf.len()) };
-}
-
-#[inline]
-pub fn aead_enc_into(
-    ciphertext: &mut [u8],
-    key: &[u8],
-    nonce: &[u8],
-    ad: &[u8],
-    plaintext: &[u8],
-) -> Result<()> {
-    assert!(ciphertext.len() == plaintext.len() + AEAD_TAG_LEN);
-    assert!(key.len() == libsodium::crypto_aead_chacha20poly1305_IETF_KEYBYTES as usize);
-    assert!(nonce.len() == libsodium::crypto_aead_chacha20poly1305_IETF_NPUBBYTES as usize);
-    let mut clen: u64 = 0;
-    sodium_call!(
-        crypto_aead_chacha20poly1305_ietf_encrypt,
-        ciphertext.as_mut_ptr(),
-        &mut clen,
-        plaintext.as_ptr(),
-        plaintext.len() as c_ulonglong,
-        ad.as_ptr(),
-        ad.len() as c_ulonglong,
-        nullptr(), // nsec is not used
-        nonce.as_ptr(),
-        key.as_ptr()
-    )?;
-    assert!(clen as usize == ciphertext.len());
-    Ok(())
-}
-
-#[inline]
-pub fn aead_dec_into(
-    plaintext: &mut [u8],
-    key: &[u8],
-    nonce: &[u8],
-    ad: &[u8],
-    ciphertext: &[u8],
-) -> Result<()> {
-    assert!(ciphertext.len() == plaintext.len() + AEAD_TAG_LEN);
-    assert!(key.len() == libsodium::crypto_aead_chacha20poly1305_IETF_KEYBYTES as usize);
-    assert!(nonce.len() == libsodium::crypto_aead_chacha20poly1305_IETF_NPUBBYTES as usize);
-    let mut mlen: u64 = 0;
-    sodium_call!(
-        crypto_aead_chacha20poly1305_ietf_decrypt,
-        plaintext.as_mut_ptr(),
-        &mut mlen as *mut c_ulonglong,
-        nullptr_mut(), // nsec is not used
-        ciphertext.as_ptr(),
-        ciphertext.len() as c_ulonglong,
-        ad.as_ptr(),
-        ad.len() as c_ulonglong,
-        nonce.as_ptr(),
-        key.as_ptr()
-    )?;
-    assert!(mlen as usize == plaintext.len());
-    Ok(())
-}
-
-#[inline]
-pub fn xaead_enc_into(
-    ciphertext: &mut [u8],
-    key: &[u8],
-    nonce: &[u8],
-    ad: &[u8],
-    plaintext: &[u8],
-) -> Result<()> {
-    assert!(ciphertext.len() == plaintext.len() + XAEAD_NONCE_LEN + XAEAD_TAG_LEN);
-    assert!(key.len() == libsodium::crypto_aead_xchacha20poly1305_IETF_KEYBYTES as usize);
-    let (n, ct) = ciphertext.split_at_mut(XAEAD_NONCE_LEN);
-    n.copy_from_slice(nonce);
-    let mut clen: u64 = 0;
-    sodium_call!(
-        crypto_aead_xchacha20poly1305_ietf_encrypt,
-        ct.as_mut_ptr(),
-        &mut clen,
-        plaintext.as_ptr(),
-        plaintext.len() as c_ulonglong,
-        ad.as_ptr(),
-        ad.len() as c_ulonglong,
-        nullptr(), // nsec is not used
-        nonce.as_ptr(),
-        key.as_ptr()
-    )?;
-    assert!(clen as usize == ct.len());
-    Ok(())
-}
-
-#[inline]
-pub fn xaead_dec_into(
-    plaintext: &mut [u8],
-    key: &[u8],
-    ad: &[u8],
-    ciphertext: &[u8],
-) -> Result<()> {
-    assert!(ciphertext.len() == plaintext.len() + XAEAD_NONCE_LEN + XAEAD_TAG_LEN);
-    assert!(key.len() == libsodium::crypto_aead_xchacha20poly1305_IETF_KEYBYTES as usize);
-    let (n, ct) = ciphertext.split_at(XAEAD_NONCE_LEN);
-    let mut mlen: u64 = 0;
-    sodium_call!(
-        crypto_aead_xchacha20poly1305_ietf_decrypt,
-        plaintext.as_mut_ptr(),
-        &mut mlen as *mut c_ulonglong,
-        nullptr_mut(), // nsec is not used
-        ct.as_ptr(),
-        ct.len() as c_ulonglong,
-        ad.as_ptr(),
-        ad.len() as c_ulonglong,
-        n.as_ptr(),
-        key.as_ptr()
-    )?;
-    assert!(mlen as usize == plaintext.len());
-    Ok(())
-}
-
-#[inline]
-fn blake2b_flexible(out: &mut [u8], key: &[u8], data: &[u8]) -> Result<()> {
-    const KEY_MIN: usize = libsodium::crypto_generichash_KEYBYTES_MIN as usize;
-    const KEY_MAX: usize = libsodium::crypto_generichash_KEYBYTES_MAX as usize;
-    const OUT_MIN: usize = libsodium::crypto_generichash_BYTES_MIN as usize;
-    const OUT_MAX: usize = libsodium::crypto_generichash_BYTES_MAX as usize;
-    assert!(key.is_empty() || (KEY_MIN <= key.len() && key.len() <= KEY_MAX));
-    assert!(OUT_MIN <= out.len() && out.len() <= OUT_MAX);
-    let kptr = match key.len() {
-        // NULL key
-        0 => nullptr(),
-        _ => key.as_ptr(),
-    };
-    sodium_call!(
-        crypto_generichash_blake2b,
-        out.as_mut_ptr(),
-        out.len(),
-        data.as_ptr(),
-        data.len() as c_ulonglong,
-        kptr,
-        key.len()
-    )
-}
-
-// TODO: Use proper streaming hash; for mix_hash too.
-#[inline]
-pub fn hash_into(out: &mut [u8], data: &[u8]) -> Result<()> {
-    assert!(out.len() == KEY_SIZE);
-    blake2b_flexible(out, &NOTHING, data)
-}
-
-#[inline]
-pub fn hash(data: &[u8]) -> Result<[u8; KEY_SIZE]> {
-    let mut r = [0u8; KEY_SIZE];
-    hash_into(&mut r, data)?;
-    Ok(r)
-}
-
-#[inline]
-pub fn mac_into(out: &mut [u8], key: &[u8], data: &[u8]) -> Result<()> {
-    assert!(out.len() == KEY_SIZE);
-    assert!(key.len() == KEY_SIZE);
-    blake2b_flexible(out, key, data)
-}
-
-#[inline]
-pub fn mac(key: &[u8], data: &[u8]) -> Result<[u8; KEY_SIZE]> {
-    let mut r = [0u8; KEY_SIZE];
-    mac_into(&mut r, key, data)?;
-    Ok(r)
-}
-
-#[inline]
-pub fn mac16(key: &[u8], data: &[u8]) -> Result<[u8; 16]> {
-    assert!(key.len() == KEY_SIZE);
-    let mut out = [0u8; 16];
-    blake2b_flexible(&mut out, key, data)?;
-    Ok(out)
-}
-
-#[inline]
-pub fn hmac_into(out: &mut [u8], key: &[u8], data: &[u8]) -> Result<()> {
-    // Not bothering with padding; the implementation
-    // uses appropriately sized keys.
-    ensure!(key.len() == KEY_SIZE);
-
-    const IPAD: [u8; KEY_SIZE] = [0x36u8; KEY_SIZE];
-    let mut temp_key = [0u8; KEY_SIZE];
-    temp_key.copy_from_slice(key);
-    xor_into(&mut temp_key, &IPAD);
-    let outer_data = mac(&temp_key, data)?;
-
-    const OPAD: [u8; KEY_SIZE] = [0x5Cu8; KEY_SIZE];
-    temp_key.copy_from_slice(key);
-    xor_into(&mut temp_key, &OPAD);
-    mac_into(out, &temp_key, &outer_data)
-}
-
-#[inline]
-pub fn hmac(key: &[u8], data: &[u8]) -> Result<[u8; KEY_SIZE]> {
-    let mut r = [0u8; KEY_SIZE];
-    hmac_into(&mut r, key, data)?;
-    Ok(r)
-}
-
-// Choose a fully random u64
-pub fn rand_u64() -> u64 {
-    let mut buf = [0u8; 8];
-    rng(&mut buf);
-    u64::from_le_bytes(buf)
-}
-
-// Choose a random f64 in [0; 1] inclusive; quick and dirty
-pub fn rand_f64() -> f64 {
-    (rand_u64() as f64) / (u64::MAX as f64)
-}

rosenpass/src/util.rs

@@ -1,244 +0,0 @@
-//! Helper functions and macros
-use anyhow::{ensure, Context, Result};
-use base64::{
-    display::Base64Display as B64Display, read::DecoderReader as B64Reader,
-    write::EncoderWriter as B64Writer,
-};
-use std::{
-    borrow::{Borrow, BorrowMut},
-    cmp::min,
-    fs::{File, OpenOptions},
-    io::{Read, Write},
-    path::Path,
-    time::{Duration, Instant},
-};
-
-use crate::coloring::{Public, Secret};
-
-/// Xors a and b element-wise and writes the result into a.
-///
-/// # Examples
-///
-/// ```
-/// use rosenpass::util::xor_into;
-/// let mut a = String::from("hello").into_bytes();
-/// let b = b"world";
-/// xor_into(&mut a, b);
-/// assert_eq!(&a, b"\x1f\n\x1e\x00\x0b");
-/// ```
-#[inline]
-pub fn xor_into(a: &mut [u8], b: &[u8]) {
-    assert!(a.len() == b.len());
-    for (av, bv) in a.iter_mut().zip(b.iter()) {
-        *av ^= *bv;
-    }
-}
-
-/// Concatenate two byte arrays
-// TODO: Zeroize result?
-#[macro_export]
-macro_rules! cat {
-    ($len:expr; $($toks:expr),+) => {{
-        let mut buf = [0u8; $len];
-        let mut off = 0;
-        $({
-            let tok = $toks;
-            let tr = ::std::borrow::Borrow::<[u8]>::borrow(tok);
-            (&mut buf[off..(off + tr.len())]).copy_from_slice(tr);
-            off += tr.len();
-        })+
-        assert!(off == buf.len(), "Size mismatch in cat!()");
-        buf
-    }}
-}
-
-// TODO: consistent inout ordering
-pub fn cpy<T: BorrowMut<[u8]> + ?Sized, F: Borrow<[u8]> + ?Sized>(src: &F, dst: &mut T) {
-    dst.borrow_mut().copy_from_slice(src.borrow());
-}
-
-/// Copy from `src` to `dst`. If `src` and `dst` are not of equal length, copy as many bytes as possible.
-pub fn cpy_min<T: BorrowMut<[u8]> + ?Sized, F: Borrow<[u8]> + ?Sized>(src: &F, dst: &mut T) {
-    let src = src.borrow();
-    let dst = dst.borrow_mut();
-    let len = min(src.len(), dst.len());
-    dst[..len].copy_from_slice(&src[..len]);
-}
-
-/// Try block basically…returns a result and allows the use of the question mark operator inside
-#[macro_export]
-macro_rules! attempt {
-    ($block:expr) => {
-        (|| -> ::anyhow::Result<_> { $block })()
-    };
-}
-
-use base64::engine::general_purpose::GeneralPurpose as Base64Engine;
-const B64ENGINE: Base64Engine = base64::engine::general_purpose::STANDARD;
-
-pub fn fmt_b64<'a>(payload: &'a [u8]) -> B64Display<'a, 'static, Base64Engine> {
-    B64Display::<'a, 'static>::new(payload, &B64ENGINE)
-}
-
-pub fn b64_writer<W: Write>(w: W) -> B64Writer<'static, Base64Engine, W> {
-    B64Writer::new(w, &B64ENGINE)
-}
-
-pub fn b64_reader<R: Read>(r: R) -> B64Reader<'static, Base64Engine, R> {
-    B64Reader::new(r, &B64ENGINE)
-}
-
-// TODO remove this once std::cmp::max becomes const
-pub const fn max_usize(a: usize, b: usize) -> usize {
-    if a > b {
-        a
-    } else {
-        b
-    }
-}
-
-#[derive(Clone, Debug)]
-pub struct Timebase(Instant);
-
-impl Default for Timebase {
-    fn default() -> Self {
-        Self(Instant::now())
-    }
-}
-
-impl Timebase {
-    pub fn now(&self) -> f64 {
-        self.0.elapsed().as_secs_f64()
-    }
-
-    pub fn dur(&self, t: f64) -> Duration {
-        Duration::from_secs_f64(t)
-    }
-}
-
-pub fn mutating<T, F>(mut v: T, f: F) -> T
-where
-    F: Fn(&mut T),
-{
-    f(&mut v);
-    v
-}
-
-pub fn sideeffect<T, F>(v: T, f: F) -> T
-where
-    F: Fn(&T),
-{
-    f(&v);
-    v
-}
-
-/// load'n store
-
-/// Open a file writable
-pub fn fopen_w<P: AsRef<Path>>(path: P) -> Result<File> {
-    Ok(OpenOptions::new()
-        .read(false)
-        .write(true)
-        .create(true)
-        .truncate(true)
-        .open(path)?)
-}
-/// Open a file readable
-pub fn fopen_r<P: AsRef<Path>>(path: P) -> Result<File> {
-    Ok(OpenOptions::new()
-        .read(true)
-        .write(false)
-        .create(false)
-        .truncate(false)
-        .open(path)?)
-}
-
-pub trait ReadExactToEnd {
-    fn read_exact_to_end(&mut self, buf: &mut [u8]) -> Result<()>;
-}
-
-impl<R: Read> ReadExactToEnd for R {
-    fn read_exact_to_end(&mut self, buf: &mut [u8]) -> Result<()> {
-        let mut dummy = [0u8; 8];
-        self.read_exact(buf)?;
-        ensure!(self.read(&mut dummy)? == 0, "File too long!");
-        Ok(())
-    }
-}
-
-pub trait LoadValue {
-    fn load<P: AsRef<Path>>(path: P) -> Result<Self>
-    where
-        Self: Sized;
-}
-
-pub trait LoadValueB64 {
-    fn load_b64<P: AsRef<Path>>(path: P) -> Result<Self>
-    where
-        Self: Sized;
-}
-
-trait StoreValue {
-    fn store<P: AsRef<Path>>(&self, path: P) -> Result<()>;
-}
-
-trait StoreSecret {
-    fn store_secret<P: AsRef<Path>>(&self, path: P) -> Result<()>;
-}
-
-impl<T: StoreValue> StoreSecret for T {
-    fn store_secret<P: AsRef<Path>>(&self, path: P) -> Result<()> {
-        self.store(path)
-    }
-}
-
-impl<const N: usize> LoadValue for Secret<N> {
-    fn load<P: AsRef<Path>>(path: P) -> Result<Self> {
-        let mut v = Self::random();
-        let p = path.as_ref();
-        fopen_r(p)?
-            .read_exact_to_end(v.secret_mut())
-            .with_context(|| format!("Could not load file {p:?}"))?;
-        Ok(v)
-    }
-}
-
-impl<const N: usize> LoadValueB64 for Secret<N> {
-    fn load_b64<P: AsRef<Path>>(path: P) -> Result<Self> {
-        let mut v = Self::random();
-        let p = path.as_ref();
-        // This might leave some fragments of the secret on the stack;
-        // in practice this is likely not a problem because the stack likely
-        // will be overwritten by something else soon but this is not exactly
-        // guaranteed. It would be possible to remedy this, but since the secret
-        // data will linger in the Linux page cache anyways with the current
-        // implementation, going to great length to erase the secret here is
-        // not worth it right now.
-        b64_reader(&mut fopen_r(p)?)
-            .read_exact(v.secret_mut())
-            .with_context(|| format!("Could not load base64 file {p:?}"))?;
-        Ok(v)
-    }
-}
-
-impl<const N: usize> StoreSecret for Secret<N> {
-    fn store_secret<P: AsRef<Path>>(&self, path: P) -> Result<()> {
-        std::fs::write(path, self.secret())?;
-        Ok(())
-    }
-}
-
-impl<const N: usize> LoadValue for Public<N> {
-    fn load<P: AsRef<Path>>(path: P) -> Result<Self> {
-        let mut v = Self::random();
-        fopen_r(path)?.read_exact_to_end(&mut *v)?;
-        Ok(v)
-    }
-}
-
-impl<const N: usize> StoreValue for Public<N> {
-    fn store<P: AsRef<Path>>(&self, path: P) -> Result<()> {
-        std::fs::write(path, **self)?;
-        Ok(())
-    }
-}

rosenpass/tests/integration_test.rs

@@ -30,11 +30,8 @@ fn generate_keys() {
 
 fn find_udp_socket() -> u16 {
     for port in 1025..=u16::MAX {
-        match UdpSocket::bind(("127.0.0.1", port)) {
+        if UdpSocket::bind(("127.0.0.1", port)).is_ok() {
-            Ok(_) => {
+            return port;
-                return port;
-            }
-            _ => {}
         }
     }
     panic!("no free UDP port found");
@@ -54,9 +51,9 @@ fn check_exchange() {
     for (secret_key_path, pub_key_path) in secret_key_paths.iter().zip(public_key_paths.iter()) {
         let output = test_bin::get_test_bin(BIN)
             .args(["gen-keys", "--secret-key"])
-            .arg(&secret_key_path)
+            .arg(secret_key_path)
             .arg("--public-key")
-            .arg(&pub_key_path)
+            .arg(pub_key_path)
             .output()
             .expect("Failed to start {BIN}");
 

secret-memory/Cargo.toml

@@ -0,0 +1,23 @@
+[package]
+name = "rosenpass-secret-memory"
+version = "0.1.0"
+authors = ["Karolin Varner <karo@cupdev.net>", "wucke13 <wucke13@gmail.com>"]
+edition = "2021"
+license = "MIT OR Apache-2.0"
+description = "Rosenpass internal utilities for storing secrets in memory"
+homepage = "https://rosenpass.eu/"
+repository = "https://github.com/rosenpass/rosenpass"
+readme = "readme.md"
+
+[dependencies]
+anyhow = { workspace = true }
+rosenpass-to = { workspace = true }
+rosenpass-util = { workspace = true }
+zeroize = { workspace = true }
+rand = { workspace = true }
+memsec = { workspace = true }
+allocator-api2 = { workspace = true }
+log = { workspace = true }
+
+[dev-dependencies]
+allocator-api2-tests = { workspace = true }

secret-memory/readme.md

@@ -0,0 +1,5 @@
+# Rosenpass secure memory library
+
+Rosenpass internal library providing utilities for securely storing secret data in memory.
+
+This is an internal library; not guarantee is made about its API at this point in time.

secret-memory/src/alloc/memsec.rs

@@ -0,0 +1,108 @@
+use std::fmt;
+use std::ptr::NonNull;
+
+use allocator_api2::alloc::{AllocError, Allocator, Layout};
+
+#[derive(Copy, Clone, Default)]
+struct MemsecAllocatorContents;
+
+/// Memory allocation using using the memsec crate
+#[derive(Copy, Clone, Default)]
+pub struct MemsecAllocator {
+    _dummy_private_data: MemsecAllocatorContents,
+}
+
+/// A box backed by the memsec allocator
+pub type MemsecBox<T> = allocator_api2::boxed::Box<T, MemsecAllocator>;
+
+/// A vector backed by the memsec allocator
+pub type MemsecVec<T> = allocator_api2::vec::Vec<T, MemsecAllocator>;
+
+pub fn memsec_box<T>(x: T) -> MemsecBox<T> {
+    MemsecBox::<T>::new_in(x, MemsecAllocator::new())
+}
+
+pub fn memsec_vec<T>() -> MemsecVec<T> {
+    MemsecVec::<T>::new_in(MemsecAllocator::new())
+}
+
+impl MemsecAllocator {
+    pub fn new() -> Self {
+        Self {
+            _dummy_private_data: MemsecAllocatorContents,
+        }
+    }
+}
+
+unsafe impl Allocator for MemsecAllocator {
+    fn allocate(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError> {
+        // Call memsec allocator
+        let mem: Option<NonNull<[u8]>> = unsafe { memsec::malloc_sized(layout.size()) };
+
+        // Unwrap the option
+        let Some(mem) = mem else {
+            log::error!("Allocation {layout:?} was requested but memsec returned a null pointer");
+            return Err(AllocError);
+        };
+
+        // Ensure the right alignment is used
+        let off = (mem.as_ptr() as *const u8).align_offset(layout.align());
+        if off != 0 {
+            log::error!("Allocation {layout:?} was requested but memsec returned allocation \
+                with offset {off} from the requested alignment. Memsec always allocates values \
+                at the end of a memory page for security reasons, custom alignments are not supported. \
+                You could try allocating an oversized value.");
+            unsafe { memsec::free(mem) };
+            return Err(AllocError);
+        };
+
+        Ok(mem)
+    }
+
+    unsafe fn deallocate(&self, ptr: NonNull<u8>, _layout: Layout) {
+        unsafe {
+            memsec::free(ptr);
+        }
+    }
+}
+
+impl fmt::Debug for MemsecAllocator {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.write_str("<memsec based Rust allocator>")
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use allocator_api2_tests::make_test;
+
+    use super::*;
+
+    make_test! { test_sizes(MemsecAllocator::new()) }
+    make_test! { test_vec(MemsecAllocator::new()) }
+    make_test! { test_many_boxes(MemsecAllocator::new()) }
+
+    #[test]
+    fn memsec_allocation() {
+        let alloc = MemsecAllocator::new();
+        memsec_allocation_impl::<0>(&alloc);
+        memsec_allocation_impl::<7>(&alloc);
+        memsec_allocation_impl::<8>(&alloc);
+        memsec_allocation_impl::<64>(&alloc);
+        memsec_allocation_impl::<999>(&alloc);
+    }
+
+    fn memsec_allocation_impl<const N: usize>(alloc: &MemsecAllocator) {
+        let layout = Layout::new::<[u8; N]>();
+        let mem = alloc.allocate(layout).unwrap();
+
+        // https://libsodium.gitbook.io/doc/memory_management#guarded-heap-allocations
+        // promises us that allocated memory is initialized with the magic byte 0xDB
+        // and memsec promises to provide a reimplementation of the libsodium mechanism;
+        // it uses the magic value 0xD0 though
+        assert_eq!(unsafe { mem.as_ref() }, &[0xD0u8; N]);
+
+        let mem = NonNull::new(mem.as_ptr() as *mut u8).unwrap();
+        unsafe { alloc.deallocate(mem, layout) };
+    }
+}

secret-memory/src/alloc/mod.rs

@@ -0,0 +1,6 @@
+pub mod memsec;
+
+pub use crate::alloc::memsec::{
+    memsec_box as secret_box, memsec_vec as secret_vec, MemsecAllocator as SecretAllocator,
+    MemsecBox as SecretBox, MemsecVec as SecretVec,
+};

secret-memory/src/debug.rs

@@ -0,0 +1,20 @@
+use std::fmt;
+
+/// Writes the contents of an `&[u8]` as hexadecimal symbols to a [std::fmt::Formatter]
+pub fn debug_crypto_array(v: &[u8], fmt: &mut fmt::Formatter) -> fmt::Result {
+    fmt.write_str("[{}]=")?;
+    if v.len() > 64 {
+        for byte in &v[..32] {
+            std::fmt::LowerHex::fmt(byte, fmt)?;
+        }
+        fmt.write_str("…")?;
+        for byte in &v[v.len() - 32..] {
+            std::fmt::LowerHex::fmt(byte, fmt)?;
+        }
+    } else {
+        for byte in v {
+            std::fmt::LowerHex::fmt(byte, fmt)?;
+        }
+    }
+    Ok(())
+}

secret-memory/src/file.rs

@@ -0,0 +1,7 @@
+use std::path::Path;
+
+pub trait StoreSecret {
+    type Error;
+
+    fn store_secret<P: AsRef<Path>>(&self, path: P) -> Result<(), Self::Error>;
+}

secret-memory/src/lib.rs

@@ -0,0 +1,11 @@
+pub mod debug;
+pub mod file;
+pub mod rand;
+
+pub mod alloc;
+
+mod public;
+pub use crate::public::Public;
+
+mod secret;
+pub use crate::secret::Secret;

secret-memory/src/public.rs

@@ -0,0 +1,112 @@
+use crate::debug::debug_crypto_array;
+use rand::{Fill as Randomize, Rng};
+use rosenpass_to::{ops::copy_slice, To};
+use rosenpass_util::file::{fopen_r, LoadValue, ReadExactToEnd, StoreValue};
+use rosenpass_util::functional::mutating;
+use std::borrow::{Borrow, BorrowMut};
+use std::fmt;
+use std::ops::{Deref, DerefMut};
+use std::path::Path;
+
+/// Contains information in the form of a byte array that may be known to the
+/// public
+// TODO: We should get rid of the Public type; just use a normal value
+#[derive(Copy, Clone, Hash, PartialEq, Eq, PartialOrd, Ord)]
+#[repr(transparent)]
+pub struct Public<const N: usize> {
+    pub value: [u8; N],
+}
+
+impl<const N: usize> Public<N> {
+    /// Create a new [Public] from a byte slice
+    pub fn from_slice(value: &[u8]) -> Self {
+        copy_slice(value).to_this(Self::zero)
+    }
+
+    /// Create a new [Public] from a byte array
+    pub fn new(value: [u8; N]) -> Self {
+        Self { value }
+    }
+
+    /// Create a zero initialized [Public]
+    pub fn zero() -> Self {
+        Self { value: [0u8; N] }
+    }
+
+    /// Create a random initialized [Public]
+    pub fn random() -> Self {
+        mutating(Self::zero(), |r| r.randomize())
+    }
+
+    /// Randomize all bytes in an existing [Public]
+    pub fn randomize(&mut self) {
+        self.try_fill(&mut crate::rand::rng()).unwrap()
+    }
+}
+
+impl<const N: usize> Randomize for Public<N> {
+    fn try_fill<R: Rng + ?Sized>(&mut self, rng: &mut R) -> Result<(), rand::Error> {
+        self.value.try_fill(rng)
+    }
+}
+
+impl<const N: usize> fmt::Debug for Public<N> {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        debug_crypto_array(&self.value, fmt)
+    }
+}
+
+impl<const N: usize> Deref for Public<N> {
+    type Target = [u8; N];
+
+    fn deref(&self) -> &[u8; N] {
+        &self.value
+    }
+}
+
+impl<const N: usize> DerefMut for Public<N> {
+    fn deref_mut(&mut self) -> &mut [u8; N] {
+        &mut self.value
+    }
+}
+
+impl<const N: usize> Borrow<[u8; N]> for Public<N> {
+    fn borrow(&self) -> &[u8; N] {
+        &self.value
+    }
+}
+impl<const N: usize> BorrowMut<[u8; N]> for Public<N> {
+    fn borrow_mut(&mut self) -> &mut [u8; N] {
+        &mut self.value
+    }
+}
+
+impl<const N: usize> Borrow<[u8]> for Public<N> {
+    fn borrow(&self) -> &[u8] {
+        &self.value
+    }
+}
+impl<const N: usize> BorrowMut<[u8]> for Public<N> {
+    fn borrow_mut(&mut self) -> &mut [u8] {
+        &mut self.value
+    }
+}
+
+impl<const N: usize> LoadValue for Public<N> {
+    type Error = anyhow::Error;
+
+    fn load<P: AsRef<Path>>(path: P) -> anyhow::Result<Self> {
+        let mut v = Self::random();
+        fopen_r(path)?.read_exact_to_end(&mut *v)?;
+        Ok(v)
+    }
+}
+
+impl<const N: usize> StoreValue for Public<N> {
+    type Error = anyhow::Error;
+
+    fn store<P: AsRef<Path>>(&self, path: P) -> anyhow::Result<()> {
+        std::fs::write(path, **self)?;
+        Ok(())
+    }
+}

secret-memory/src/rand.rs

@@ -0,0 +1,5 @@
+pub type Rng = rand::rngs::ThreadRng;
+
+pub fn rng() -> Rng {
+    rand::thread_rng()
+}

secret-memory/src/secret.rs

@@ -0,0 +1,321 @@
+use std::cell::RefCell;
+use std::collections::HashMap;
+use std::convert::TryInto;
+use std::fmt;
+use std::ops::{Deref, DerefMut};
+use std::path::Path;
+
+use anyhow::Context;
+use rand::{Fill as Randomize, Rng};
+use zeroize::{Zeroize, ZeroizeOnDrop};
+
+use rosenpass_util::b64::b64_reader;
+use rosenpass_util::file::{fopen_r, LoadValue, LoadValueB64, ReadExactToEnd};
+use rosenpass_util::functional::mutating;
+
+use crate::alloc::{secret_box, SecretBox, SecretVec};
+use crate::file::StoreSecret;
+
+// This might become a problem in library usage; it's effectively a memory
+// leak which probably isn't a problem right now because most memory will
+// be reused…
+thread_local! {
+    static SECRET_CACHE: RefCell<SecretMemoryPool> = RefCell::new(SecretMemoryPool::new());
+}
+
+fn with_secret_memory_pool<Fn, R>(mut f: Fn) -> R
+where
+    Fn: FnMut(Option<&mut SecretMemoryPool>) -> R,
+{
+    // This acquires the SECRET_CACHE
+    SECRET_CACHE
+        .try_with(|cell| {
+            // And acquires the inner reference
+            cell.try_borrow_mut()
+                .as_deref_mut()
+                // To call the given function
+                .map(|pool| f(Some(pool)))
+                .ok()
+        })
+        .ok()
+        .flatten()
+        // Failing that, the given function is called with None
+        .unwrap_or_else(|| f(None))
+}
+
+// Wrapper around SecretBox that applies automatic zeroization
+#[derive(Debug)]
+struct ZeroizingSecretBox<T: Zeroize + ?Sized>(Option<SecretBox<T>>);
+
+impl<T: Zeroize> ZeroizingSecretBox<T> {
+    fn new(boxed: T) -> Self {
+        ZeroizingSecretBox(Some(secret_box(boxed)))
+    }
+}
+
+impl<T: Zeroize + ?Sized> ZeroizingSecretBox<T> {
+    fn from_secret_box(inner: SecretBox<T>) -> Self {
+        Self(Some(inner))
+    }
+
+    fn take(mut self) -> SecretBox<T> {
+        self.0.take().unwrap()
+    }
+}
+
+impl<T: Zeroize + ?Sized> ZeroizeOnDrop for ZeroizingSecretBox<T> {}
+impl<T: Zeroize + ?Sized> Zeroize for ZeroizingSecretBox<T> {
+    fn zeroize(&mut self) {
+        if let Some(inner) = &mut self.0 {
+            let inner: &mut SecretBox<T> = inner; // type annotation
+            inner.zeroize()
+        }
+    }
+}
+
+impl<T: Zeroize + ?Sized> Drop for ZeroizingSecretBox<T> {
+    fn drop(&mut self) {
+        self.zeroize()
+    }
+}
+
+impl<T: Zeroize + ?Sized> Deref for ZeroizingSecretBox<T> {
+    type Target = T;
+
+    fn deref(&self) -> &T {
+        self.0.as_ref().unwrap()
+    }
+}
+
+impl<T: Zeroize + ?Sized> DerefMut for ZeroizingSecretBox<T> {
+    fn deref_mut(&mut self) -> &mut T {
+        self.0.as_mut().unwrap()
+    }
+}
+
+/// Pool that stores secret memory allocations
+///
+/// Allocation of secret memory is expensive. Thus, this struct provides a
+/// pool of secret memory, readily available to yield protected, slices of
+/// memory.
+#[derive(Debug)] // TODO check on Debug derive, is that clever
+struct SecretMemoryPool {
+    pool: HashMap<usize, Vec<ZeroizingSecretBox<[u8]>>>,
+}
+
+impl SecretMemoryPool {
+    /// Create a new [SecretMemoryPool]
+    #[allow(clippy::new_without_default)]
+    pub fn new() -> Self {
+        Self {
+            pool: HashMap::new(),
+        }
+    }
+
+    /// Return secret back to the pool for future re-use
+    pub fn release<const N: usize>(&mut self, mut sec: ZeroizingSecretBox<[u8; N]>) {
+        sec.zeroize();
+
+        // This conversion sequence is weird but at least it guarantees
+        // that the heap allocation is preserved according to the docs
+        let sec: SecretVec<u8> = sec.take().into();
+        let sec: SecretBox<[u8]> = sec.into();
+
+        self.pool
+            .entry(N)
+            .or_default()
+            .push(ZeroizingSecretBox::from_secret_box(sec));
+    }
+
+    /// Take protected memory from the pool, allocating new one if no suitable
+    /// chunk is found in the inventory.
+    ///
+    /// The secret is guaranteed to be full of nullbytes
+    pub fn take<const N: usize>(&mut self) -> ZeroizingSecretBox<[u8; N]> {
+        let entry = self.pool.entry(N).or_default();
+        let inner = match entry.pop() {
+            None => secret_box([0u8; N]),
+            Some(sec) => sec.take().try_into().unwrap(),
+        };
+        ZeroizingSecretBox::from_secret_box(inner)
+    }
+}
+
+/// Storage for secret data
+pub struct Secret<const N: usize> {
+    storage: Option<ZeroizingSecretBox<[u8; N]>>,
+}
+
+impl<const N: usize> Secret<N> {
+    pub fn from_slice(slice: &[u8]) -> Self {
+        let mut new_self = Self::zero();
+        new_self.secret_mut().copy_from_slice(slice);
+        new_self
+    }
+
+    /// Returns a new [Secret] that is zero initialized
+    pub fn zero() -> Self {
+        // Using [SecretMemoryPool] here because this operation is expensive,
+        // yet it is used in hot loops
+        let buf = with_secret_memory_pool(|pool| {
+            pool.map(|p| p.take())
+                .unwrap_or_else(|| ZeroizingSecretBox::new([0u8; N]))
+        });
+
+        Self { storage: Some(buf) }
+    }
+
+    /// Returns a new [Secret] that is randomized
+    pub fn random() -> Self {
+        mutating(Self::zero(), |r| r.randomize())
+    }
+
+    /// Sets all data an existing secret to random bytes
+    pub fn randomize(&mut self) {
+        self.try_fill(&mut crate::rand::rng()).unwrap()
+    }
+
+    /// Borrows the data
+    pub fn secret(&self) -> &[u8; N] {
+        self.storage.as_ref().unwrap()
+    }
+
+    /// Borrows the data mutably
+    pub fn secret_mut(&mut self) -> &mut [u8; N] {
+        self.storage.as_mut().unwrap()
+    }
+}
+
+impl<const N: usize> Randomize for Secret<N> {
+    fn try_fill<R: Rng + ?Sized>(&mut self, rng: &mut R) -> Result<(), rand::Error> {
+        // Zeroize self first just to make sure the barriers from the zeroize create take
+        // effect to prevent the compiler from optimizing this away.
+        // We should at some point replace this with our own barriers.
+        self.zeroize();
+        self.secret_mut().try_fill(rng)
+    }
+}
+
+impl<const N: usize> ZeroizeOnDrop for Secret<N> {}
+impl<const N: usize> Zeroize for Secret<N> {
+    fn zeroize(&mut self) {
+        if let Some(inner) = &mut self.storage {
+            inner.zeroize()
+        }
+    }
+}
+
+impl<const N: usize> Drop for Secret<N> {
+    fn drop(&mut self) {
+        with_secret_memory_pool(|pool| {
+            if let Some((pool, secret)) = pool.zip(self.storage.take()) {
+                pool.release(secret);
+            }
+        });
+
+        // This should be unnecessary: The pool has one item – the inner secret – which
+        // zeroizes itself on drop. Calling it should not do any harm though…
+        self.zeroize()
+    }
+}
+
+impl<const N: usize> Clone for Secret<N> {
+    fn clone(&self) -> Self {
+        Self::from_slice(self.secret())
+    }
+}
+
+/// The Debug implementation of [Secret] does not reveal the secret data,
+/// instead a placeholder `<SECRET>` is used
+impl<const N: usize> fmt::Debug for Secret<N> {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.write_str("<SECRET>")
+    }
+}
+
+impl<const N: usize> LoadValue for Secret<N> {
+    type Error = anyhow::Error;
+
+    fn load<P: AsRef<Path>>(path: P) -> anyhow::Result<Self> {
+        let mut v = Self::random();
+        let p = path.as_ref();
+        fopen_r(p)?
+            .read_exact_to_end(v.secret_mut())
+            .with_context(|| format!("Could not load file {p:?}"))?;
+        Ok(v)
+    }
+}
+
+impl<const N: usize> LoadValueB64 for Secret<N> {
+    type Error = anyhow::Error;
+
+    fn load_b64<P: AsRef<Path>>(path: P) -> anyhow::Result<Self> {
+        use std::io::Read;
+
+        let mut v = Self::random();
+        let p = path.as_ref();
+        // This might leave some fragments of the secret on the stack;
+        // in practice this is likely not a problem because the stack likely
+        // will be overwritten by something else soon but this is not exactly
+        // guaranteed. It would be possible to remedy this, but since the secret
+        // data will linger in the Linux page cache anyways with the current
+        // implementation, going to great length to erase the secret here is
+        // not worth it right now.
+        b64_reader(&mut fopen_r(p)?)
+            .read_exact(v.secret_mut())
+            .with_context(|| format!("Could not load base64 file {p:?}"))?;
+        Ok(v)
+    }
+}
+
+impl<const N: usize> StoreSecret for Secret<N> {
+    type Error = anyhow::Error;
+
+    fn store_secret<P: AsRef<Path>>(&self, path: P) -> anyhow::Result<()> {
+        std::fs::write(path, self.secret())?;
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    /// check that we can alloc using the magic pool
+    #[test]
+    fn secret_memory_pool_take() {
+        const N: usize = 0x100;
+        let mut pool = SecretMemoryPool::new();
+        let secret: ZeroizingSecretBox<[u8; N]> = pool.take();
+        assert_eq!(secret.as_ref(), &[0; N]);
+    }
+
+    /// check that a secrete lives, even if its [SecretMemoryPool] is deleted
+    #[test]
+    fn secret_memory_pool_drop() {
+        const N: usize = 0x100;
+        let mut pool = SecretMemoryPool::new();
+        let secret: ZeroizingSecretBox<[u8; N]> = pool.take();
+        std::mem::drop(pool);
+        assert_eq!(secret.as_ref(), &[0; N]);
+    }
+
+    /// check that a secrete can be reborn, freshly initialized with zero
+    #[test]
+    fn secret_memory_pool_release() {
+        const N: usize = 1;
+        let mut pool = SecretMemoryPool::new();
+        let mut secret: ZeroizingSecretBox<[u8; N]> = pool.take();
+        let old_secret_ptr = secret.as_ref().as_ptr();
+
+        secret.as_mut()[0] = 0x13;
+        pool.release(secret);
+
+        // now check that we get the same ptr
+        let new_secret: ZeroizingSecretBox<[u8; N]> = pool.take();
+        assert_eq!(old_secret_ptr, new_secret.as_ref().as_ptr());
+
+        // and that the secret was zeroized
+        assert_eq!(new_secret.as_ref(), &[0; N]);
+    }
+}

to/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "rosenpass-to"
+version = "0.1.0"
+authors = ["Karolin Varner <karo@cupdev.net>", "wucke13 <wucke13@gmail.com>"]
+edition = "2021"
+license = "MIT OR Apache-2.0"
+description = "Flexible destination parameters"
+homepage = "https://rosenpass.eu/"
+repository = "https://github.com/rosenpass/rosenpass"
+readme = "readme.md"
+
+[dev-dependencies]
+doc-comment = { workspace = true }

to/README.md

@@ -0,0 +1,510 @@
+# The To Crate – Patterns for dealing with destination parameters in rust functions
+
+<!-- The code blocks in this file double as tests. -->
+
+![crates.io](https://img.shields.io/crates/v/rosenpass-to.svg)
+![Libraries.io dependency status for latest release](https://img.shields.io/librariesio/release/cargo/rosenpass-to)
+
+The To Crate provides a pattern for declaring and dealing with destination parameters in rust functions. It improves over stock rust by providing an interface that allows the caller to choose whether to place the destination parameter first – through a `to(dest, copy(source))` function – or last – through a chained function `copy(source).to(dest)`.
+
+The crate provides chained functions to simplify allocating the destination parameter on the fly and it provides well defined patterns for dealing with error handling and destination parameters.
+
+For now this crate is experimental; patch releases are guaranteed not to contain any breaking changes, but minor releases may.
+
+```rust
+use rosenpass_to::ops::copy_array;
+use rosenpass_to::{to, with_destination, To};
+use std::ops::BitXorAssign;
+
+// Destination functions return some value that implements the To trait.
+// Unfortunately dealing with lifetimes is a bit more finicky than it would#
+// be without destination parameters
+fn xor_slice<'a, T>(src: &'a [T]) -> impl To<[T], ()> + 'a
+where
+    T: BitXorAssign + Clone,
+{
+    // Custom implementations of the to trait can be created, but the easiest
+    with_destination(move |dst: &mut [T]| {
+        assert!(src.len() == dst.len());
+        for (d, s) in dst.iter_mut().zip(src.iter()) {
+            *d ^= s.clone();
+        }
+    })
+}
+
+let flip0 = b"\xff\x00\x00\x00";
+let flip1 = b"\x00\xff\x00\x00";
+let flip01 = b"\xff\xff\x00\x00";
+
+// You can specify a destination by using the to method
+let mut dst = [0u8; 4];
+xor_slice(flip0).to(&mut dst);
+xor_slice(flip1).to(&mut dst);
+assert_eq!(&dst[..], &flip01[..]);
+
+// Or using the to function
+let mut dst = [0u8; 4];
+to(&mut dst, xor_slice(flip0));
+to(&mut dst, xor_slice(flip1));
+assert_eq!(&dst[..], &flip01[..]);
+
+// You can pass a function to generate the destination on the fly
+let dst = xor_slice(flip1).to_this(|| flip0.to_vec());
+assert_eq!(&dst[..], &flip01[..]);
+
+// If xor_slice used a return value that could be created using Default::default(),
+// you could just use `xor_slice(flip01).to_value()` to generate the destination
+// on the fly. Since [u8] is unsized, it can only be used for references.
+//
+// You can however use collect to specify the storage value explicitly.
+// This works for any type that implements Default::default() and BorrowMut<...> for
+// the destination value.
+
+// Collect in an array with a fixed size
+let dst = xor_slice(flip01).collect::<[u8; 4]>();
+assert_eq!(&dst[..], &flip01[..]);
+
+// The builtin function copy_array supports to_value() since its
+// destination parameter is a fixed size array, which can be allocated
+// using default()
+let dst: [u8; 4] = copy_array(flip01).to_value();
+assert_eq!(&dst, flip01);
+```
+
+The to crate really starts to shine when error handling (through result) is combined with destination parameters. See the tutorial below for details.
+
+## Motivation
+
+Destination parameters are often used when simply returning the value is undesirable or impossible.
+
+Using stock rust features, functions can declare destination parameters by accepting mutable references as arguments.
+This pattern introduces some shortcomings; developers have to make a call on whether to place destination parameters before or after source parameters and they have to enforce consistency across their codebase or accept inconsistencies, leading to hard-to-remember interfaces.
+
+Functions declared like this are more cumbersome to use when the destination parameter should be allocated on the fly.
+
+```rust
+use std::ops::BitXorAssign;
+
+fn xor_slice<T>(dst: &mut [T], src: &[T])
+where
+    T: BitXorAssign + Clone,
+{
+    assert!(src.len() == dst.len());
+    for (d, s) in dst.iter_mut().zip(src.iter()) {
+        *d ^= s.clone();
+    }
+}
+
+let flip0 = b"\xff\x00\x00\x00";
+let flip1 = b"\x00\xff\x00\x00";
+let flip01 = b"\xff\xff\x00\x00";
+
+// Copy a slice from src to dest; its unclear whether src or dest should come first
+let mut dst = [0u8; 4];
+xor_slice(&mut dst, flip0);
+xor_slice(&mut dst, flip1);
+assert_eq!(&dst[..], &flip01[..]);
+
+// The other examples can not be translated to use the standard rust pattern,
+// since using mutable references for destination parameters does not allow
+// for specifying the destination parameter on the right side or allocating
+// the destination parameter on the fly.
+```
+
+## Tutorial
+
+### Using a function with destination
+
+There are a couple of ways to use a function with destination:
+
+```rust
+use rosenpass_to::ops::{copy_array, copy_slice_least};
+use rosenpass_to::{to, To};
+
+let mut dst = b"           ".to_vec();
+
+// Using the to function to have data flowing from the right to the left,
+// performing something akin to a variable assignment
+to(&mut dst[..], copy_slice_least(b"Hello World"));
+assert_eq!(&dst[..], b"Hello World");
+
+// Using the to method to have information flowing from the left to the right
+copy_slice_least(b"This is fin").to(&mut dst[..]);
+assert_eq!(&dst[..], b"This is fin");
+
+// You can allocate the destination variable on the fly using `.to_this(...)`
+let tmp =
+    copy_slice_least(b"This is new---").to_this(|| b"This will be overwritten".to_owned());
+assert_eq!(&tmp[..], b"This is new---verwritten");
+
+// You can allocate the destination variable on the fly `.collect(..)` if it implements default
+let tmp = copy_slice_least(b"This is ad-hoc").collect::<[u8; 16]>();
+assert_eq!(&tmp[..], b"This is ad-hoc\0\0");
+
+// Finally, if the destination variable specified by the function implements default,
+// you can simply use `.to_value()` to allocate it on the fly.
+let tmp = copy_array(b"Fixed").to_value();
+assert_eq!(&tmp[..], b"Fixed");
+```
+
+### Builtin functions with destination
+
+The to crate provides basic functions with destination for copying data between slices and arrays.
+
+```rust
+use rosenpass_to::ops::{
+    copy_array, copy_slice, copy_slice_least, copy_slice_least_src, try_copy_slice,
+    try_copy_slice_least_src,
+};
+use rosenpass_to::{to, To};
+
+let mut dst = b"           ".to_vec();
+
+// Copy a slice, source and destination must match exactly
+to(&mut dst[..], copy_slice(b"Hello World"));
+assert_eq!(&dst[..], b"Hello World");
+
+// Copy a slice, destination must be at least as long as the destination
+to(&mut dst[4..], copy_slice_least_src(b"!!!"));
+assert_eq!(&dst[..], b"Hell!!!orld");
+
+// Copy a slice, copying as many bytes as possible
+to(
+    &mut dst[6..],
+    copy_slice_least(b"xxxxxxxxxxxxxxxxxxxxxxxxxxxxx"),
+);
+assert_eq!(&dst[..], b"Hell!!xxxxx");
+
+// Copy a slice, will return None and abort if the sizes do not much
+assert_eq!(Some(()), to(&mut dst[..], try_copy_slice(b"Hello World")));
+assert_eq!(None, to(&mut dst[..], try_copy_slice(b"---")));
+assert_eq!(
+    None,
+    to(&mut dst[..], try_copy_slice(b"---------------------"))
+);
+assert_eq!(&dst[..], b"Hello World");
+
+// Copy a slice, will return None and abort if source is longer than destination
+assert_eq!(
+    Some(()),
+    to(&mut dst[4..], try_copy_slice_least_src(b"!!!"))
+);
+assert_eq!(
+    None,
+    to(
+        &mut dst[4..],
+        try_copy_slice_least_src(b"-------------------------")
+    )
+);
+assert_eq!(&dst[..], b"Hell!!!orld");
+
+// Copy fixed size arrays all at once
+let mut dst = [0u8; 5];
+to(&mut dst, copy_array(b"Hello"));
+assert_eq!(&dst, b"Hello");
+```
+
+### Declaring a function with destination
+
+The easiest way to declare a function with destination is to use the with_destination function.
+
+```rust
+use rosenpass_to::ops::copy_array;
+use rosenpass_to::{to, with_destination, To};
+
+/// Copy the given slice to the start of a vector, reusing its memory if possible
+fn copy_to_vec<'a, T>(src: &'a [T]) -> impl To<Vec<T>, ()> + 'a
+where
+    T: Clone,
+{
+    with_destination(move |dst: &mut Vec<T>| {
+        dst.clear();
+        dst.extend_from_slice(src);
+    })
+}
+
+let mut buf = copy_to_vec(b"Hello World, this is a long text.").to_value();
+assert_eq!(&buf[..], b"Hello World, this is a long text.");
+
+to(&mut buf, copy_to_vec(b"Avoids allocation"));
+assert_eq!(&buf[..], b"Avoids allocation");
+```
+
+This example also shows of some of the advantages of using To: The function gains a very slight allocate over using `.to_vec()` by reusing memory:
+
+```rust
+let mut buf = b"Hello World, this is a long text.".to_vec();
+buf = b"This allocates".to_vec(); // This uses memory allocation
+```
+
+The same pattern can be implemented without `to`, at the cost of being slightly more verbose
+
+```rust
+/// Copy the given slice to the start of a vector, reusing its memory if possible
+fn copy_to_vec<T>(dst: &mut Vec<T>, src: &[T])
+where
+    T: Clone,
+{
+    dst.clear();
+    dst.extend_from_slice(src);
+}
+
+let mut buf = Vec::default();
+copy_to_vec(&mut buf, b"Hello World, this is a long text.");
+assert_eq!(&buf[..], b"Hello World, this is a long text.");
+
+copy_to_vec(&mut buf, b"Avoids allocation");
+assert_eq!(&buf[..], b"Avoids allocation");
+```
+
+This usability enhancement might seem minor, but when many functions take destination parameters, manually allocating all of these can really become annoying.
+
+## Beside values: Functions with destination and return value
+
+Return values are supported, but `from_this()`, `to_value()`, and `collect()` cannot be used together with return values (unless they implement CondenseBeside – see the next section), since that would erase the return value.
+
+Alternative functions are returned, that return a `to::Beside` value, containing both the
+destination variable and the return value.
+
+```rust
+use rosenpass_to::{to, with_destination, Beside, To};
+use std::cmp::{max, min};
+
+/// Copy an array of floats and calculate the average
+pub fn copy_and_average<'a>(src: &'a [f64]) -> impl To<[f64], f64> + 'a {
+    with_destination(move |dst: &mut [f64]| {
+        assert!(src.len() == dst.len());
+        let mut sum = 0f64;
+        for (d, s) in dst.iter_mut().zip(src.iter()) {
+            *d = *s;
+            sum = sum + *d;
+        }
+        sum / (src.len() as f64)
+    })
+}
+
+let src = [12f64, 13f64, 14f64];
+
+// `.to()` and `to(...)` function as normal, but return the value now
+let mut dst = [0f64; 3];
+let avg = copy_and_average(&src).to(&mut dst);
+assert_eq!((&dst[..], avg), (&src[..], 13f64));
+
+let mut dst = [0f64; 3];
+let avg = to(&mut dst, copy_and_average(&src));
+assert_eq!((&dst[..], avg), (&src[..], 13f64));
+
+// Instead of .to_this, .to_value, or .collect variants returning a beside value have to be used
+
+let Beside(dst, avg) = copy_and_average(&src).to_this_beside(|| [0f64; 3]);
+assert_eq!((&dst[..], avg), (&src[..], 13f64));
+
+let Beside(dst, avg) = copy_and_average(&src).collect_beside::<[f64; 3]>();
+assert_eq!((&dst[..], avg), (&src[..], 13f64));
+
+// Beside values are simple named tuples
+
+let b = copy_and_average(&src).collect_beside::<[f64; 3]>();
+assert_eq!(b, Beside(dst, avg));
+
+// They can convert from and to tuples
+let b_tup = (dst, avg);
+assert_eq!(b, (dst, avg).into());
+assert_eq!(b, Beside::from(b_tup));
+
+// Simple accessors for the value and returned value are provided
+assert_eq!(&dst, b.dest());
+assert_eq!(&avg, b.ret());
+
+let mut tmp = b;
+*tmp.dest_mut() = [42f64; 3];
+*tmp.ret_mut() = 42f64;
+assert_eq!(tmp, Beside([42f64; 3], 42f64));
+```
+
+## Beside Condensation: Working with destinations and Optional or Result
+
+When Beside values contain a `()`, `Option<()>`, or `Result<(), Error>` return value, they expose a special method called `.condense()`; this method consumes the Beside value and condenses destination and return value into one value.
+
+```rust
+use rosenpass_to::Beside;
+use std::result::Result;
+
+assert_eq!((), Beside((), ()).condense());
+
+assert_eq!(42, Beside(42, ()).condense());
+assert_eq!(None, Beside(42, None).condense());
+
+let ok_unit = Result::<(), ()>::Ok(());
+assert_eq!(Ok(42), Beside(42, ok_unit).condense());
+
+let err_unit = Result::<(), ()>::Err(());
+assert_eq!(Err(()), Beside(42, err_unit).condense());
+```
+
+When condense is implemented for a type, `.to_this(|| ...)`, `.to_value()`, and `.collect::<...>()` on the `To` trait can be used even with a return value:
+
+```rust
+use rosenpass_to::ops::try_copy_slice;
+use rosenpass_to::To;
+
+let tmp = try_copy_slice(b"Hello World").collect::<[u8; 11]>();
+assert_eq!(tmp, Some(*b"Hello World"));
+
+let tmp = try_copy_slice(b"Hello World").collect::<[u8; 2]>();
+assert_eq!(tmp, None);
+
+let tmp = try_copy_slice(b"Hello World").to_this(|| [0u8; 11].to_vec());
+assert_eq!(tmp, Some(b"Hello World".to_vec()));
+
+let tmp = try_copy_slice(b"Hello World").to_this(|| [0u8; 2].to_vec());
+assert_eq!(tmp, None);
+```
+
+The same naturally also works for Results, but the example is a bit harder to motivate:
+
+```rust
+use rosenpass_to::{to, with_destination, To};
+use std::result::Result;
+
+#[derive(PartialEq, Eq, Debug, Default)]
+struct InvalidFloat;
+
+fn check_float(f: f64) -> Result<(), InvalidFloat> {
+    if f.is_normal() || f == 0.0 {
+        Ok(())
+    } else {
+        Err(InvalidFloat)
+    }
+}
+
+fn checked_add<'a>(src: f64) -> impl To<f64, Result<(), InvalidFloat>> + 'a {
+    with_destination(move |dst: &mut f64| {
+        check_float(src)?;
+        check_float(*dst)?;
+        *dst += src;
+        Ok(())
+    })
+}
+
+let mut tmp = 0.0;
+checked_add(14.0).to(&mut tmp).unwrap();
+checked_add(12.0).to(&mut tmp).unwrap();
+assert_eq!(tmp, 26.0);
+
+assert_eq!(Ok(78.0), checked_add(14.0).to_this(|| 64.0));
+assert_eq!(Ok(14.0), checked_add(14.0).to_value());
+assert_eq!(Ok(14.0), checked_add(14.0).collect());
+
+assert_eq!(Err(InvalidFloat), checked_add(f64::NAN).to_this(|| 64.0));
+assert_eq!(Err(InvalidFloat), checked_add(f64::INFINITY).to_value());
+```
+
+## Custom condensation
+
+Condensation is implemented through a trait called CondenseBeside ([local](CondenseBeside) | [docs.rs](https://docs.rs/to/latest/rosenpass-to/trait.CondenseBeside.html)). You can implement it for your own types.
+
+If you can not implement this trait because its for an external type (see [orphan rule](https://doc.rust-lang.org/book/ch10-02-traits.html#implementing-a-trait-on-a-type)), this crate welcomes contributions of new Condensation rules.
+
+```rust
+use rosenpass_to::ops::copy_slice;
+use rosenpass_to::{with_destination, Beside, CondenseBeside, To};
+
+#[derive(PartialEq, Eq, Debug, Default)]
+struct MyTuple<Left, Right>(Left, Right);
+
+impl<Val, Right> CondenseBeside<Val> for MyTuple<(), Right> {
+    type Condensed = MyTuple<Val, Right>;
+
+    fn condense(self, val: Val) -> MyTuple<Val, Right> {
+        let MyTuple((), right) = self;
+        MyTuple(val, right)
+    }
+}
+
+fn copy_slice_and_return_something<'a, T, U>(src: &'a [T], something: U) -> impl To<[T], U> + 'a
+where
+    T: Copy,
+    U: 'a,
+{
+    with_destination(move |dst: &mut [T]| {
+        copy_slice(src).to(dst);
+        something
+    })
+}
+
+let tmp = Beside(42, MyTuple((), 23)).condense();
+assert_eq!(tmp, MyTuple(42, 23));
+
+let tmp = copy_slice_and_return_something(b"23", MyTuple((), 42)).collect::<[u8; 2]>();
+assert_eq!(tmp, MyTuple(*b"23", 42));
+```
+
+## Manually implementing the To trait
+
+Using `with_destination(...)` is convenient, but since it uses closures it results in an type that can not be written down, which is why the `-> impl To<...>` pattern is used everywhere in this tutorial.
+
+Implementing the ToTrait manual is the right choice for library use cases.
+
+```rust
+use rosenpass_to::{to, with_destination, To};
+
+struct TryCopySliceSource<'a, T: Copy> {
+    src: &'a [T],
+}
+
+impl<'a, T: Copy> To<[T], Option<()>> for TryCopySliceSource<'a, T> {
+    fn to(self, dst: &mut [T]) -> Option<()> {
+        (self.src.len() == dst.len()).then(|| dst.copy_from_slice(self.src))
+    }
+}
+
+fn try_copy_slice<'a, T>(src: &'a [T]) -> TryCopySliceSource<'a, T>
+where
+    T: Copy,
+{
+    TryCopySliceSource { src }
+}
+
+let mut dst = try_copy_slice(b"Hello World")
+    .collect::<[u8; 11]>()
+    .unwrap();
+assert_eq!(&dst[..], b"Hello World");
+assert_eq!(None, to(&mut dst[..], try_copy_slice(b"---")));
+```
+
+## Methods with destination
+
+Destinations can also be used with methods. This example demonstrates using destinations in an extension trait for everything that implements `Borrow<[T]>` for any `T` and a concrete `To` trait implementation.
+
+```rust
+use rosenpass_to::{to, with_destination, To};
+use std::borrow::Borrow;
+
+struct TryCopySliceSource<'a, T: Copy> {
+    src: &'a [T],
+}
+
+impl<'a, T: Copy> To<[T], Option<()>> for TryCopySliceSource<'a, T> {
+    fn to(self, dst: &mut [T]) -> Option<()> {
+        (self.src.len() == dst.len()).then(|| dst.copy_from_slice(self.src))
+    }
+}
+
+trait TryCopySliceExt<'a, T: Copy> {
+    fn try_copy_slice(&'a self) -> TryCopySliceSource<'a, T>;
+}
+
+impl<'a, T: 'a + Copy, Ref: 'a + Borrow<[T]>> TryCopySliceExt<'a, T> for Ref {
+    fn try_copy_slice(&'a self) -> TryCopySliceSource<'a, T> {
+        TryCopySliceSource { src: self.borrow() }
+    }
+}
+
+let mut dst = b"Hello World"
+    .try_copy_slice()
+    .collect::<[u8; 11]>()
+    .unwrap();
+assert_eq!(&dst[..], b"Hello World");
+assert_eq!(None, to(&mut dst[..], b"---".try_copy_slice()));
+```

to/src/lib.rs

@@ -0,0 +1,14 @@
+#![doc = include_str!(concat!(env!("CARGO_MANIFEST_DIR"), "/README.md"))]
+
+#[cfg(doctest)]
+doc_comment::doctest!("../README.md");
+
+// Core implementation
+mod to;
+pub use crate::to::{
+    beside::Beside, condense::CondenseBeside, dst_coercion::DstCoercion, to_function::to,
+    to_trait::To, with_destination::with_destination,
+};
+
+// Example use cases
+pub mod ops;

to/src/ops.rs

@@ -0,0 +1,80 @@
+//! Functions with destination copying data between slices and arrays.
+
+use crate::{with_destination, To};
+
+/// Function with destination that copies data from
+/// origin into the destination.
+///
+/// # Panics
+///
+/// This function will panic if the two slices have different lengths.
+pub fn copy_slice<T>(origin: &[T]) -> impl To<[T], ()> + '_
+where
+    T: Copy,
+{
+    with_destination(|out: &mut [T]| out.copy_from_slice(origin))
+}
+
+/// Function with destination that copies all data from
+/// origin into the destination.
+///
+/// Destination may be longer than origin.
+///
+/// # Panics
+///
+/// This function will panic if destination is shorter than origin.
+pub fn copy_slice_least_src<T>(origin: &[T]) -> impl To<[T], ()> + '_
+where
+    T: Copy,
+{
+    with_destination(|out: &mut [T]| copy_slice(origin).to(&mut out[..origin.len()]))
+}
+
+/// Function with destination that copies as much data as possible from origin to the
+/// destination.
+///
+/// Copies as much data as is present in the shorter slice.
+pub fn copy_slice_least<T>(origin: &[T]) -> impl To<[T], ()> + '_
+where
+    T: Copy,
+{
+    with_destination(|out: &mut [T]| {
+        let len = std::cmp::min(origin.len(), out.len());
+        copy_slice(&origin[..len]).to(&mut out[..len])
+    })
+}
+
+/// Function with destination that attempts to copy data from origin into the destination.
+///
+/// Will return None if the slices are of different lengths.
+pub fn try_copy_slice<T>(origin: &[T]) -> impl To<[T], Option<()>> + '_
+where
+    T: Copy,
+{
+    with_destination(|out: &mut [T]| {
+        (origin.len() == out.len()).then(|| copy_slice(origin).to(out))
+    })
+}
+
+/// Function with destination that tries to copy all data from
+/// origin into the destination.
+///
+/// Destination may be longer than origin.
+///
+/// Will return None if the destination is shorter than origin.
+pub fn try_copy_slice_least_src<T>(origin: &[T]) -> impl To<[T], Option<()>> + '_
+where
+    T: Copy,
+{
+    with_destination(|out: &mut [T]| {
+        (origin.len() <= out.len()).then(|| copy_slice_least_src(origin).to(out))
+    })
+}
+
+/// Function with destination that copies all data between two array references.
+pub fn copy_array<T, const N: usize>(origin: &[T; N]) -> impl To<[T; N], ()> + '_
+where
+    T: Copy,
+{
+    with_destination(|out: &mut [T; N]| out.copy_from_slice(origin))
+}

to/src/to/beside.rs

@@ -0,0 +1,45 @@
+use crate::CondenseBeside;
+
+/// Named tuple holding the return value and the output from a function with destinations.
+#[derive(Debug, PartialEq, Eq, Default, PartialOrd, Ord, Copy, Clone)]
+pub struct Beside<Val, Ret>(pub Val, pub Ret);
+
+impl<Val, Ret> Beside<Val, Ret> {
+    pub fn dest(&self) -> &Val {
+        &self.0
+    }
+
+    pub fn ret(&self) -> &Ret {
+        &self.1
+    }
+
+    pub fn dest_mut(&mut self) -> &mut Val {
+        &mut self.0
+    }
+
+    pub fn ret_mut(&mut self) -> &mut Ret {
+        &mut self.1
+    }
+
+    /// Perform beside condensation. See [CondenseBeside]
+    pub fn condense(self) -> <Ret as CondenseBeside<Val>>::Condensed
+    where
+        Ret: CondenseBeside<Val>,
+    {
+        self.1.condense(self.0)
+    }
+}
+
+impl<Val, Ret> From<(Val, Ret)> for Beside<Val, Ret> {
+    fn from(tuple: (Val, Ret)) -> Self {
+        let (val, ret) = tuple;
+        Self(val, ret)
+    }
+}
+
+impl<Val, Ret> From<Beside<Val, Ret>> for (Val, Ret) {
+    fn from(beside: Beside<Val, Ret>) -> Self {
+        let Beside(val, ret) = beside;
+        (val, ret)
+    }
+}

to/src/to/condense.rs

@@ -0,0 +1,37 @@
+/// Beside condensation.
+///
+/// This trait can be used to enable the use of [to_this(|| ...)](crate::To::to_this),
+/// [to_value()](crate::To::to_value), and [collect::<...>()](crate::To::collect) with custom
+/// types.
+///
+/// The function [Beside::condense()](crate::Beside::condense) is a shorthand for using the
+/// condense trait.
+pub trait CondenseBeside<Val> {
+    type Condensed;
+
+    fn condense(self, ret: Val) -> Self::Condensed;
+}
+
+impl<Val> CondenseBeside<Val> for () {
+    type Condensed = Val;
+
+    fn condense(self, ret: Val) -> Val {
+        ret
+    }
+}
+
+impl<Val, Error> CondenseBeside<Val> for Result<(), Error> {
+    type Condensed = Result<Val, Error>;
+
+    fn condense(self, ret: Val) -> Result<Val, Error> {
+        self.map(|()| ret)
+    }
+}
+
+impl<Val> CondenseBeside<Val> for Option<()> {
+    type Condensed = Option<Val>;
+
+    fn condense(self, ret: Val) -> Option<Val> {
+        self.map(|()| ret)
+    }
+}

to/src/to/dst_coercion.rs

@@ -0,0 +1,17 @@
+/// Helper performing explicit unsized coercion.
+/// Used by the [to](crate::to()) function.
+pub trait DstCoercion<Dst: ?Sized> {
+    fn coerce_dest(&mut self) -> &mut Dst;
+}
+
+impl<T: ?Sized> DstCoercion<T> for T {
+    fn coerce_dest(&mut self) -> &mut T {
+        self
+    }
+}
+
+impl<T, const N: usize> DstCoercion<[T]> for [T; N] {
+    fn coerce_dest(&mut self) -> &mut [T] {
+        self
+    }
+}

to/src/to/mod.rs

@@ -0,0 +1,20 @@
+//! Module implementing the core function with destination functionality.
+//!
+//! Parameter naming scheme
+//!
+//! - `Src: impl To<Dst, Ret>` – The value of an instance of something implementing the `To` trait
+//! - `Dst: ?Sized`; (e.g. [u8]) – The target to write to
+//! - `Out: Sized = &mut Dst`; (e.g. &mut [u8]) – A reference to the target to write to
+//! - `Coercable: ?Sized + DstCoercion<Dst>`; (e.g. `[u8]`, `[u8; 16]`) – Some value that
+//! destination coercion can be applied to. Usually either `Dst` itself (e.g. `[u8]` or some sized variant of
+//! `Dst` (e.g. `[u8; 64]`).
+//! - `Ret: Sized`; (anything) – must be `CondenseBeside<_>` if condensing is to be applied. The ordinary return value of a function with an output
+//! - `Val: Sized + BorrowMut<Dst>`; (e.g. [u8; 16]) – Some owned storage that can be borrowed as `Dst`
+//! - `Condensed: Sized = CondenseBeside<Val>::Condensed`; (e.g. [u8; 16], Result<[u8; 16]>) – The combiation of Val and Ret after condensing was applied (`Beside<Val, Ret>::condense()`/`Ret::condense(v)` for all `v : Val`).
+
+pub mod beside;
+pub mod condense;
+pub mod dst_coercion;
+pub mod to_function;
+pub mod to_trait;
+pub mod with_destination;

to/src/to/to_function.rs

@@ -0,0 +1,14 @@
+use crate::{DstCoercion, To};
+
+/// Alias for [To::to] moving the destination to the left.
+///
+/// This provides similar haptics to the let assignment syntax is rust, which also keeps
+/// the variable to assign to on the left and the generating function on the right.
+pub fn to<Coercable, Src, Dst, Ret>(dst: &mut Coercable, src: Src) -> Ret
+where
+    Coercable: ?Sized + DstCoercion<Dst>,
+    Src: To<Dst, Ret>,
+    Dst: ?Sized,
+{
+    src.to(dst.coerce_dest())
+}

to/src/to/to_trait.rs

@@ -0,0 +1,96 @@
+use crate::{Beside, CondenseBeside};
+use std::borrow::BorrowMut;
+
+// The To trait is the core of the to crate; most functions with destinations will either return
+// an object that is an instance of this trait or they will return `-> impl To<Destination,
+// Return_value`.
+//
+// A quick way to implement a function with destination is to use the
+// [with_destination(|param: &mut Type| ...)] higher order function.
+pub trait To<Dst: ?Sized, Ret>: Sized {
+    fn to(self, out: &mut Dst) -> Ret;
+
+    /// Generate a destination on the fly with a lambda.
+    ///
+    /// Calls the provided closure to create a value,
+    /// calls [crate::to()] to evaluate the function and finally
+    /// returns a [Beside] instance containing the generated destination value and the return
+    /// value.
+    fn to_this_beside<Val, Fun>(self, fun: Fun) -> Beside<Val, Ret>
+    where
+        Val: BorrowMut<Dst>,
+        Fun: FnOnce() -> Val,
+    {
+        let mut val = fun();
+        let ret = self.to(val.borrow_mut());
+        Beside(val, ret)
+    }
+
+    /// Generate a destination on the fly using default.
+    ///
+    /// Uses [Default] to create a value,
+    /// calls [crate::to()] to evaluate the function and finally
+    /// returns a [Beside] instance containing the generated destination value and the return
+    /// value.
+    fn to_value_beside(self) -> Beside<Dst, Ret>
+    where
+        Dst: Sized + Default,
+    {
+        self.to_this_beside(|| Dst::default())
+    }
+
+    /// Generate a destination on the fly using default and a custom storage type.
+    ///
+    /// Uses [Default] to create a value of the given type,
+    /// calls [crate::to()] to evaluate the function and finally
+    /// returns a [Beside] instance containing the generated destination value and the return
+    /// value.
+    ///
+    /// Using collect_beside with an explicit type instead of [Self::to_value_beside] is mainly useful
+    /// when the Destination is unsized.
+    ///
+    /// This could be the case when the destination is an `[u8]` for instance.
+    fn collect_beside<Val>(self) -> Beside<Val, Ret>
+    where
+        Val: Default + BorrowMut<Dst>,
+    {
+        self.to_this_beside(|| Val::default())
+    }
+
+    /// Generate a destination on the fly with a lambda, condensing the destination and the
+    /// return value into one.
+    ///
+    /// This is like using [Self::to_this_beside] followed by calling [Beside::condense].
+    fn to_this<Val, Fun>(self, fun: Fun) -> <Ret as CondenseBeside<Val>>::Condensed
+    where
+        Ret: CondenseBeside<Val>,
+        Val: BorrowMut<Dst>,
+        Fun: FnOnce() -> Val,
+    {
+        self.to_this_beside(fun).condense()
+    }
+
+    /// Generate a destination on the fly using default, condensing the destination and the
+    /// return value into one.
+    ///
+    /// This is like using [Self::to_value_beside] followed by calling [Beside::condense].
+    fn to_value(self) -> <Ret as CondenseBeside<Dst>>::Condensed
+    where
+        Dst: Sized + Default,
+        Ret: CondenseBeside<Dst>,
+    {
+        self.to_value_beside().condense()
+    }
+
+    /// Generate a destination on the fly using default, condensing the destination and the
+    /// return value into one.
+    ///
+    /// This is like using [Self::collect_beside] followed by calling [Beside::condense].
+    fn collect<Val>(self) -> <Ret as CondenseBeside<Val>>::Condensed
+    where
+        Val: Default + BorrowMut<Dst>,
+        Ret: CondenseBeside<Val>,
+    {
+        self.collect_beside::<Val>().condense()
+    }
+}

to/src/to/with_destination.rs

@@ -0,0 +1,35 @@
+use crate::To;
+use std::marker::PhantomData;
+
+struct ToClosure<Dst, Ret, Fun>
+where
+    Dst: ?Sized,
+    Fun: FnOnce(&mut Dst) -> Ret,
+{
+    fun: Fun,
+    _val: PhantomData<Box<Dst>>,
+}
+
+impl<Dst, Ret, Fun> To<Dst, Ret> for ToClosure<Dst, Ret, Fun>
+where
+    Dst: ?Sized,
+    Fun: FnOnce(&mut Dst) -> Ret,
+{
+    fn to(self, out: &mut Dst) -> Ret {
+        (self.fun)(out)
+    }
+}
+
+/// Used to create a function with destination.
+///
+/// See the tutorial in [readme.me]..
+pub fn with_destination<Dst, Ret, Fun>(fun: Fun) -> impl To<Dst, Ret>
+where
+    Dst: ?Sized,
+    Fun: FnOnce(&mut Dst) -> Ret,
+{
+    ToClosure {
+        fun,
+        _val: PhantomData,
+    }
+}

util/Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+name = "rosenpass-util"
+version = "0.1.0"
+authors = ["Karolin Varner <karo@cupdev.net>", "wucke13 <wucke13@gmail.com>"]
+edition = "2021"
+license = "MIT OR Apache-2.0"
+description = "Rosenpass internal utilities"
+homepage = "https://rosenpass.eu/"
+repository = "https://github.com/rosenpass/rosenpass"
+readme = "readme.md"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+base64 = { workspace = true }
+anyhow = { workspace = true }
+rustix = { workspace = true }
+typenum = { workspace = true }
+static_assertions = { workspace = true }

util/src/b64.rs

@@ -0,0 +1,20 @@
+use base64::{
+    display::Base64Display as B64Display, read::DecoderReader as B64Reader,
+    write::EncoderWriter as B64Writer,
+};
+use std::io::{Read, Write};
+
+use base64::engine::general_purpose::GeneralPurpose as Base64Engine;
+const B64ENGINE: Base64Engine = base64::engine::general_purpose::STANDARD;
+
+pub fn fmt_b64<'a>(payload: &'a [u8]) -> B64Display<'a, 'static, Base64Engine> {
+    B64Display::<'a, 'static>::new(payload, &B64ENGINE)
+}
+
+pub fn b64_writer<W: Write>(w: W) -> B64Writer<'static, Base64Engine, W> {
+    B64Writer::new(w, &B64ENGINE)
+}
+
+pub fn b64_reader<R: Read>(r: R) -> B64Reader<'static, Base64Engine, R> {
+    B64Reader::new(r, &B64ENGINE)
+}

util/src/fd.rs

@@ -0,0 +1,12 @@
+use std::os::fd::{OwnedFd, RawFd};
+
+/// Clone some file descriptor
+///
+/// If the file descriptor is invalid, an error will be raised.
+pub fn claim_fd(fd: RawFd) -> anyhow::Result<OwnedFd> {
+    use rustix::{fd::BorrowedFd, io::dup};
+
+    // This is safe since [dup] will simply raise
+    let fd = unsafe { dup(BorrowedFd::borrow_raw(fd))? };
+    Ok(fd)
+}

util/src/file.rs

@@ -0,0 +1,63 @@
+use anyhow::ensure;
+use std::fs::File;
+use std::io::Read;
+use std::result::Result;
+use std::{fs::OpenOptions, path::Path};
+
+/// Open a file writable
+pub fn fopen_w<P: AsRef<Path>>(path: P) -> std::io::Result<File> {
+    OpenOptions::new()
+        .read(false)
+        .write(true)
+        .create(true)
+        .truncate(true)
+        .open(path)
+}
+/// Open a file readable
+pub fn fopen_r<P: AsRef<Path>>(path: P) -> std::io::Result<File> {
+    OpenOptions::new()
+        .read(true)
+        .write(false)
+        .create(false)
+        .truncate(false)
+        .open(path)
+}
+
+pub trait ReadExactToEnd {
+    type Error;
+
+    fn read_exact_to_end(&mut self, buf: &mut [u8]) -> Result<(), Self::Error>;
+}
+
+impl<R: Read> ReadExactToEnd for R {
+    type Error = anyhow::Error;
+
+    fn read_exact_to_end(&mut self, buf: &mut [u8]) -> anyhow::Result<()> {
+        let mut dummy = [0u8; 8];
+        self.read_exact(buf)?;
+        ensure!(self.read(&mut dummy)? == 0, "File too long!");
+        Ok(())
+    }
+}
+
+pub trait LoadValue {
+    type Error;
+
+    fn load<P: AsRef<Path>>(path: P) -> Result<Self, Self::Error>
+    where
+        Self: Sized;
+}
+
+pub trait LoadValueB64 {
+    type Error;
+
+    fn load_b64<P: AsRef<Path>>(path: P) -> Result<Self, Self::Error>
+    where
+        Self: Sized;
+}
+
+pub trait StoreValue {
+    type Error;
+
+    fn store<P: AsRef<Path>>(&self, path: P) -> Result<(), Self::Error>;
+}

util/src/functional.rs

@@ -0,0 +1,15 @@
+pub fn mutating<T, F>(mut v: T, f: F) -> T
+where
+    F: Fn(&mut T),
+{
+    f(&mut v);
+    v
+}
+
+pub fn sideeffect<T, F>(v: T, f: F) -> T
+where
+    F: Fn(&T),
+{
+    f(&v);
+    v
+}

util/src/lib.rs

@@ -0,0 +1,11 @@
+#![recursion_limit = "256"]
+
+pub mod b64;
+pub mod fd;
+pub mod file;
+pub mod functional;
+pub mod mem;
+pub mod ord;
+pub mod result;
+pub mod time;
+pub mod typenum;

util/src/mem.rs

@@ -0,0 +1,33 @@
+use std::borrow::{Borrow, BorrowMut};
+use std::cmp::min;
+
+/// Concatenate two byte arrays
+// TODO: Zeroize result?
+#[macro_export]
+macro_rules! cat {
+    ($len:expr; $($toks:expr),+) => {{
+        let mut buf = [0u8; $len];
+        let mut off = 0;
+        $({
+            let tok = $toks;
+            let tr = ::std::borrow::Borrow::<[u8]>::borrow(tok);
+            (&mut buf[off..(off + tr.len())]).copy_from_slice(tr);
+            off += tr.len();
+        })+
+        assert!(off == buf.len(), "Size mismatch in cat!()");
+        buf
+    }}
+}
+
+// TODO: consistent inout ordering
+pub fn cpy<T: BorrowMut<[u8]> + ?Sized, F: Borrow<[u8]> + ?Sized>(src: &F, dst: &mut T) {
+    dst.borrow_mut().copy_from_slice(src.borrow());
+}
+
+/// Copy from `src` to `dst`. If `src` and `dst` are not of equal length, copy as many bytes as possible.
+pub fn cpy_min<T: BorrowMut<[u8]> + ?Sized, F: Borrow<[u8]> + ?Sized>(src: &F, dst: &mut T) {
+    let src = src.borrow();
+    let dst = dst.borrow_mut();
+    let len = min(src.len(), dst.len());
+    dst[..len].copy_from_slice(&src[..len]);
+}

util/src/ord.rs

@@ -0,0 +1,8 @@
+// TODO remove this once std::cmp::max becomes const
+pub const fn max_usize(a: usize, b: usize) -> usize {
+    if a > b {
+        a
+    } else {
+        b
+    }
+}

util/src/result.rs

@@ -0,0 +1,99 @@
+use std::convert::Infallible;
+use std::result::Result;
+
+/// Try block basically…returns a result and allows the use of the question mark operator inside
+#[macro_export]
+macro_rules! attempt {
+    ($block:expr) => {
+        (|| -> ::anyhow::Result<_> { $block })()
+    };
+}
+
+/// Trait for container types that guarantee successful unwrapping.
+///
+/// The `.guaranteed()` function can be used over unwrap to show that
+/// the function will not panic.
+///
+/// Implementations must not panic.
+pub trait GuaranteedValue {
+    type Value;
+
+    /// Extract the contained value while being panic-safe, like .unwrap()
+    ///
+    /// # Panic Safety
+    ///
+    /// Implementations of guaranteed() must not panic.
+    fn guaranteed(self) -> Self::Value;
+}
+
+/// A result type that never contains an error.
+///
+/// This is mostly useful in generic contexts.
+///
+/// # Examples
+///
+/// ```
+/// use std::num::Wrapping;
+/// use std::result::Result;
+/// use std::convert::Infallible;
+/// use std::ops::Add;
+///
+/// use rosenpass_util::result::{Guaranteed, GuaranteedValue};
+///
+/// trait FailableAddition: Sized {
+///   type Error;
+///   fn failable_addition(&self, other: &Self) -> Result<Self, Self::Error>;
+/// }
+///
+/// #[derive(Copy, Clone, Debug, Eq, PartialEq)]
+/// struct OverflowError;
+///
+/// impl<T> FailableAddition for Wrapping<T>
+///   where for <'a> &'a Wrapping<T>: Add<Output = Wrapping<T>> {
+///   type Error = Infallible;
+///   fn failable_addition(&self, other: &Self) -> Guaranteed<Self> {
+///     Ok(self + other)
+///   }
+/// }
+///
+/// impl FailableAddition for u32 {
+///   type Error = OverflowError;
+///   fn failable_addition(&self, other: &Self) -> Result<Self, Self::Error> {
+///     match self.checked_add(*other) {
+///         Some(v) => Ok(v),
+///         None => Err(OverflowError),
+///     }
+///   }
+/// }
+///
+/// fn failable_multiply<T>(a: &T, b: u32)
+///         -> Result<T, T::Error>
+///     where
+///         T: FailableAddition {
+///     assert!(b >= 2); // Acceptable only because this is for demonstration purposes
+///     let mut accu = a.failable_addition(a)?;
+///     for _ in 2..b {
+///         accu = accu.failable_addition(a)?;
+///     }
+///     Ok(accu)
+/// }
+///
+/// // We can use .guaranteed() with Wrapping<u32>, since the operation uses
+/// // the Infallible error type.
+/// // We can also use unwrap which just happens to not raise an error.
+/// assert_eq!(failable_multiply(&Wrapping(42u32), 3).guaranteed(), Wrapping(126));
+/// assert_eq!(failable_multiply(&Wrapping(42u32), 3).unwrap(), Wrapping(126));
+///
+/// // We can not use .guaranteed() with u32, since there can be an error.
+/// // We can however use unwrap(), which may panic
+/// //assert_eq!(failable_multiply(&42u32, 3).guaranteed(), 126); // COMPILER ERROR
+/// assert_eq!(failable_multiply(&42u32, 3).unwrap(), 126);
+/// ```
+pub type Guaranteed<T> = Result<T, Infallible>;
+
+impl<T> GuaranteedValue for Guaranteed<T> {
+    type Value = T;
+    fn guaranteed(self) -> Self::Value {
+        self.unwrap()
+    }
+}