From efa0a3607f0faba0d0722574b470cf6d3cb36dd9 Mon Sep 17 00:00:00 2001 From: Matthias Schiffer Date: Sat, 17 Aug 2013 10:54:21 +0200 Subject: Cache values calculated in the handshake reponse to reuse them in the finish handling --- src/protocol_ec25519_fhmqvc.c | 108 ++++++++++++++++++------------------------ 1 file changed, 46 insertions(+), 62 deletions(-) diff --git a/src/protocol_ec25519_fhmqvc.c b/src/protocol_ec25519_fhmqvc.c index cd4eb30..3a66c38 100644 --- a/src/protocol_ec25519_fhmqvc.c +++ b/src/protocol_ec25519_fhmqvc.c @@ -86,6 +86,12 @@ struct fastd_protocol_peer_state { protocol_session_t session; uint64_t last_serial; + + /* handshake cache */ + uint64_t last_handshake_serial; + ecc_int256_t peer_handshake_key; + ecc_int256_t sigma; + fastd_sha256_t shared_handshake_key; }; @@ -272,9 +278,12 @@ static void protocol_handshake_init(fastd_context_t *ctx, const fastd_socket_t * fastd_send_handshake(ctx, sock, local_addr, remote_addr, buffer); } -static void respond_handshake(fastd_context_t *ctx, const fastd_socket_t *sock, const fastd_peer_address_t *local_addr, const fastd_peer_address_t *remote_addr, const fastd_peer_t *peer, - const handshake_key_t *handshake_key, const ecc_int256_t *peer_handshake_key, const fastd_handshake_t *handshake, const fastd_method_t *method) { - pr_debug(ctx, "responding handshake with %P[%I]...", peer, remote_addr); + +static bool update_shared_handshake_key(fastd_context_t *ctx, const fastd_peer_t *peer, const handshake_key_t *handshake_key, const ecc_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_t hashbuf; fastd_sha256_blocks(&hashbuf, @@ -297,36 +306,55 @@ static void respond_handshake(fastd_context_t *ctx, const fastd_socket_t *sock, ecc_25519_work_t work, workX; if (!ecc_25519_load_packed(&workX, peer_handshake_key)) - return; + return false; ecc_25519_scalarmult(&work, &ecc_25519_gf_order, &workX); if (!ecc_25519_is_identity(&work)) - return; + return false; if (!ecc_25519_load_packed(&work, &peer->protocol_config->public_key)) - return; + return false; ecc_25519_scalarmult(&work, &d, &work); ecc_25519_add(&work, &workX, &work); ecc_25519_scalarmult(&work, &s, &work); if (ecc_25519_is_identity(&work)) - return; + return false; - ecc_int256_t sigma; - ecc_25519_store_packed(&sigma, &work); + ecc_25519_store_packed(&peer->protocol_state->sigma, &work); - fastd_sha256_t shared_handshake_key; - fastd_sha256_blocks(&shared_handshake_key, + fastd_sha256_blocks(&peer->protocol_state->shared_handshake_key, handshake_key->public_key.p, peer_handshake_key->p, ctx->conf->protocol_config->public_key.p, peer->protocol_config->public_key.p, - sigma.p, + peer->protocol_state->sigma.p, NULL); + peer->protocol_state->last_handshake_serial = handshake_key->serial; + peer->protocol_state->peer_handshake_key = *peer_handshake_key; + + return true; +} + +static void clear_shared_handshake_key(fastd_context_t *ctx, const fastd_peer_t *peer) { + memset(&peer->protocol_state->sigma, 0, sizeof(peer->protocol_state->sigma)); + memset(&peer->protocol_state->shared_handshake_key, 0, sizeof(peer->protocol_state->shared_handshake_key)); + + peer->protocol_state->last_handshake_serial = 0; + memset(&peer->protocol_state->peer_handshake_key, 0, sizeof(peer->protocol_state->peer_handshake_key)); +} + +static void respond_handshake(fastd_context_t *ctx, const fastd_socket_t *sock, const fastd_peer_address_t *local_addr, const fastd_peer_address_t *remote_addr, const fastd_peer_t *peer, + const handshake_key_t *handshake_key, const ecc_int256_t *peer_handshake_key, const fastd_handshake_t *handshake, const fastd_method_t *method) { + pr_debug(ctx, "responding handshake with %P[%I]...", peer, remote_addr); + + if (!update_shared_handshake_key(ctx, peer, handshake_key, peer_handshake_key)) + return; + fastd_sha256_t hmacbuf; - fastd_hmacsha256_blocks(&hmacbuf, shared_handshake_key.w, ctx->conf->protocol_config->public_key.p, handshake_key->public_key.p, NULL); + fastd_hmacsha256_blocks(&hmacbuf, peer->protocol_state->shared_handshake_key.w, ctx->conf->protocol_config->public_key.p, handshake_key->public_key.p, NULL); fastd_buffer_t buffer = fastd_handshake_new_reply(ctx, handshake, method, 4*(4+PUBLICKEYBYTES) + 4+HASHBYTES); @@ -477,62 +505,18 @@ static void handle_finish_handshake(fastd_context_t *ctx, fastd_socket_t *sock, const fastd_handshake_t *handshake, const fastd_method_t *method) { pr_debug(ctx, "handling handshake finish with %P[%I]...", peer, remote_addr); - fastd_sha256_t hashbuf; - fastd_sha256_blocks(&hashbuf, - handshake_key->public_key.p, - peer_handshake_key->p, - ctx->conf->protocol_config->public_key.p, - peer->protocol_config->public_key.p, - NULL); - - ecc_int256_t d = {{0}}, e = {{0}}, eb, 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(&eb, &e, &ctx->conf->protocol_config->secret_key); - ecc_25519_gf_add(&s, &eb, &handshake_key->secret_key); - - ecc_25519_work_t work, workX; - if (!ecc_25519_load_packed(&workX, peer_handshake_key)) - return; - - ecc_25519_scalarmult(&work, &ecc_25519_gf_order, &workX); - if (!ecc_25519_is_identity(&work)) - return; - - if (!ecc_25519_load_packed(&work, &peer->protocol_config->public_key)) + if (!update_shared_handshake_key(ctx, peer, handshake_key, peer_handshake_key)) return; - ecc_25519_scalarmult(&work, &d, &work); - ecc_25519_add(&work, &workX, &work); - ecc_25519_scalarmult(&work, &s, &work); - - if (ecc_25519_is_identity(&work)) - return; - - ecc_int256_t sigma; - ecc_25519_store_packed(&sigma, &work); - - fastd_sha256_t shared_handshake_key; - fastd_sha256_blocks(&shared_handshake_key, - handshake_key->public_key.p, - peer_handshake_key->p, - ctx->conf->protocol_config->public_key.p, - peer->protocol_config->public_key.p, - sigma.p, - NULL); - - if (!fastd_hmacsha256_blocks_verify(handshake->records[RECORD_T].data, shared_handshake_key.w, peer->protocol_config->public_key.p, peer_handshake_key->p, NULL)) { + if (!fastd_hmacsha256_blocks_verify(handshake->records[RECORD_T].data, peer->protocol_state->shared_handshake_key.w, peer->protocol_config->public_key.p, peer_handshake_key->p, NULL)) { pr_warn(ctx, "received invalid protocol handshake finish from %P[%I]", peer, remote_addr); return; } establish(ctx, peer, method, sock, local_addr, remote_addr, false, peer_handshake_key, &handshake_key->public_key, &peer->protocol_config->public_key, - &ctx->conf->protocol_config->public_key, &sigma, handshake_key->serial); + &ctx->conf->protocol_config->public_key, &peer->protocol_state->sigma, handshake_key->serial); + + clear_shared_handshake_key(ctx, peer); } static fastd_peer_t* find_sender_key(fastd_context_t *ctx, const fastd_peer_address_t *address, const unsigned char key[32], fastd_peer_t *peers) { -- cgit v1.2.3