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-rw-r--r--src/protocols/ec25519_fhmqvc/handshake.c136
1 files changed, 57 insertions, 79 deletions
diff --git a/src/protocols/ec25519_fhmqvc/handshake.c b/src/protocols/ec25519_fhmqvc/handshake.c
index 9e62deb..75cca96 100644
--- a/src/protocols/ec25519_fhmqvc/handshake.c
+++ b/src/protocols/ec25519_fhmqvc/handshake.c
@@ -72,21 +72,26 @@ void fastd_protocol_ec25519_fhmqvc_handshake_init(fastd_context_t *ctx, const fa
}
-static bool update_shared_handshake_key(fastd_context_t *ctx, const fastd_peer_t *peer, const handshake_key_t *handshake_key, const aligned_int256_t *peer_handshake_key) {
- if (peer->protocol_state->last_handshake_serial == handshake_key->serial) {
- if (memcmp(&peer->protocol_state->peer_handshake_key, peer_handshake_key, PUBLICKEYBYTES) == 0)
- return true;
- }
+static bool make_shared_handshake_key(fastd_context_t *ctx, const handshake_key_t *handshake_key, bool initiator,
+ const aligned_int256_t *A, const aligned_int256_t *B,
+ const aligned_int256_t *X, const aligned_int256_t *Y,
+ aligned_int256_t *sigma, fastd_sha256_t *shared_handshake_key) {
+ ecc_25519_work_t work, workXY;
+
+ if (!ecc_25519_load_packed(&workXY, initiator ? Y : X))
+ return false;
+
+ ecc_25519_scalarmult(&work, &ecc_25519_gf_order, &workXY);
+ if (!ecc_25519_is_identity(&work))
+ return false;
+
+ if (!ecc_25519_load_packed(&work, initiator ? B : A))
+ return false;
fastd_sha256_t hashbuf;
- fastd_sha256_blocks(&hashbuf,
- handshake_key->key2.public.p,
- peer_handshake_key->p,
- ctx->conf->protocol_config->key.public.p,
- peer->protocol_config->public_key.p,
- NULL);
+ fastd_sha256_blocks(&hashbuf, Y->p, X->p, B->p, A->p, NULL);
- ecc_int256_t d = {{0}}, e = {{0}}, eb, s;
+ ecc_int256_t d = {{0}}, e = {{0}}, s;
memcpy(d.p, hashbuf.b, HASHBYTES/2);
memcpy(e.p, hashbuf.b+HASHBYTES/2, HASHBYTES/2);
@@ -94,36 +99,47 @@ static bool update_shared_handshake_key(fastd_context_t *ctx, const fastd_peer_t
d.p[15] |= 0x80;
e.p[15] |= 0x80;
- ecc_25519_gf_mult(&eb, &e, &ctx->conf->protocol_config->key.secret);
- ecc_25519_gf_add(&s, &eb, &handshake_key->key2.secret);
-
- ecc_25519_work_t work, workX;
- if (!ecc_25519_load_packed(&workX, peer_handshake_key))
- return false;
+ if (initiator) {
+ ecc_int256_t da;
+ ecc_25519_gf_mult(&da, &d, &ctx->conf->protocol_config->key.secret);
+ ecc_25519_gf_add(&s, &da, &handshake_key->key1.secret);
- ecc_25519_scalarmult(&work, &ecc_25519_gf_order, &workX);
- if (!ecc_25519_is_identity(&work))
- return false;
+ ecc_25519_scalarmult(&work, &e, &work);
+ }
+ else {
+ ecc_int256_t eb;
+ ecc_25519_gf_mult(&eb, &e, &ctx->conf->protocol_config->key.secret);
+ ecc_25519_gf_add(&s, &eb, &handshake_key->key2.secret);
- if (!ecc_25519_load_packed(&work, &peer->protocol_config->public_key))
- return false;
+ ecc_25519_scalarmult(&work, &d, &work);
+ }
- ecc_25519_scalarmult(&work, &d, &work);
- ecc_25519_add(&work, &workX, &work);
+ ecc_25519_add(&work, &workXY, &work);
ecc_25519_scalarmult(&work, &s, &work);
if (ecc_25519_is_identity(&work))
return false;
- ecc_25519_store_packed(&peer->protocol_state->sigma, &work);
+ ecc_25519_store_packed(sigma, &work);
+ fastd_sha256_blocks(shared_handshake_key, Y->p, X->p, B->p, A->p, sigma->p, NULL);
+
+ return true;
+}
+
+static bool update_shared_handshake_key(fastd_context_t *ctx, const fastd_peer_t *peer, const handshake_key_t *handshake_key, const aligned_int256_t *peer_handshake_key) {
+ if (peer->protocol_state->last_handshake_serial == handshake_key->serial) {
+ if (memcmp(&peer->protocol_state->peer_handshake_key, peer_handshake_key, PUBLICKEYBYTES) == 0)
+ return true;
+ }
- fastd_sha256_blocks(&peer->protocol_state->shared_handshake_key,
- handshake_key->key2.public.p,
- peer_handshake_key->p,
- ctx->conf->protocol_config->key.public.p,
- peer->protocol_config->public_key.p,
- peer->protocol_state->sigma.p,
- NULL);
+ if (!make_shared_handshake_key(ctx, handshake_key, false,
+ &peer->protocol_config->public_key,
+ &ctx->conf->protocol_config->key.public,
+ peer_handshake_key,
+ &handshake_key->key2.public,
+ &peer->protocol_state->sigma,
+ &peer->protocol_state->shared_handshake_key))
+ return false;
peer->protocol_state->last_handshake_serial = handshake_key->serial;
peer->protocol_state->peer_handshake_key = *peer_handshake_key;
@@ -243,54 +259,16 @@ static void finish_handshake(fastd_context_t *ctx, fastd_socket_t *sock, const f
const fastd_handshake_t *handshake, const char *method) {
pr_debug(ctx, "finishing handshake with %P[%I]...", peer, remote_addr);
- fastd_sha256_t hashbuf;
- fastd_sha256_blocks(&hashbuf,
- peer_handshake_key->p,
- handshake_key->key1.public.p,
- peer->protocol_config->public_key.p,
- ctx->conf->protocol_config->key.public.p,
- NULL);
-
- ecc_int256_t d = {{0}}, e = {{0}}, da, s;
-
- memcpy(d.p, hashbuf.b, HASHBYTES/2);
- memcpy(e.p, hashbuf.b+HASHBYTES/2, HASHBYTES/2);
-
- d.p[15] |= 0x80;
- e.p[15] |= 0x80;
-
- ecc_25519_gf_mult(&da, &d, &ctx->conf->protocol_config->key.secret);
- ecc_25519_gf_add(&s, &da, &handshake_key->key1.secret);
-
- ecc_25519_work_t work, workY;
- if (!ecc_25519_load_packed(&workY, peer_handshake_key))
- return;
-
- ecc_25519_scalarmult(&work, &ecc_25519_gf_order, &workY);
- if (!ecc_25519_is_identity(&work))
- return;
-
- if (!ecc_25519_load_packed(&work, &peer->protocol_config->public_key))
- return;
-
- ecc_25519_scalarmult(&work, &e, &work);
- ecc_25519_add(&work, &workY, &work);
- ecc_25519_scalarmult(&work, &s, &work);
-
- if (ecc_25519_is_identity(&work))
- return;
-
aligned_int256_t sigma;
- ecc_25519_store_packed(&sigma, &work);
-
fastd_sha256_t shared_handshake_key;
- fastd_sha256_blocks(&shared_handshake_key,
- peer_handshake_key->p,
- handshake_key->key1.public.p,
- peer->protocol_config->public_key.p,
- ctx->conf->protocol_config->key.public.p,
- sigma.p,
- NULL);
+ if (!make_shared_handshake_key(ctx, handshake_key, true,
+ &ctx->conf->protocol_config->key.public,
+ &peer->protocol_config->public_key,
+ &handshake_key->key1.public,
+ peer_handshake_key,
+ &sigma,
+ &shared_handshake_key))
+ return;
bool valid;
if (secure_handshake(handshake)) {
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-09 00:11:54 +0100