diff options
Diffstat (limited to 'src/protocol_ec25519_fhmqvc.c')
| -rw-r--r-- | src/protocol_ec25519_fhmqvc.c | 1015 |
1 files changed, 0 insertions, 1015 deletions
diff --git a/src/protocol_ec25519_fhmqvc.c b/src/protocol_ec25519_fhmqvc.c deleted file mode 100644 index b7b5162..0000000 --- a/src/protocol_ec25519_fhmqvc.c +++ /dev/null @@ -1,1015 +0,0 @@ -/* - Copyright (c) 2012-2013, Matthias Schiffer <mschiffer@universe-factory.net> - All rights reserved. - - Redistribution and use in source and binary forms, with or without - modification, are permitted provided that the following conditions are met: - - 1. Redistributions of source code must retain the above copyright notice, - this list of conditions and the following disclaimer. - 2. Redistributions in binary form must reproduce the above copyright notice, - this list of conditions and the following disclaimer in the documentation - and/or other materials provided with the distribution. - - THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" - AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE - IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE - DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE - FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL - DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR - SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER - CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, - OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE - OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. -*/ - - -#include "fastd.h" -#include "handshake.h" -#include "peer.h" -#include "sha256.h" - - -#include <libuecc/ecc.h> - - -#define PUBLICKEYBYTES 32 -#define SECRETKEYBYTES 32 -#define HASHBYTES FASTD_SHA256_HASH_BYTES - - -#if HASHBYTES != FASTD_HMACSHA256_KEY_BYTES -#error bug: HASHBYTES != FASTD_HMACSHA256_KEY_BYTES -#endif - -#if HASHBYTES != SECRETKEYBYTES -#error bug: HASHBYTES != SECRETKEYBYTES -#endif - - -typedef ecc_int256_t __attribute__((aligned(4))) aligned_int256_t; - -typedef struct keypair { - ecc_int256_t secret; - aligned_int256_t public; -} keypair_t; - -struct fastd_protocol_config { - keypair_t key; -}; - -typedef struct handshake_key { - uint64_t serial; - struct timespec preferred_till; - struct timespec valid_till; - - /* keypair used as initiator */ - keypair_t key1; - - /* keypair used as responder */ - keypair_t key2; -} handshake_key_t; - -struct fastd_protocol_state { - handshake_key_t prev_handshake_key; - handshake_key_t handshake_key; -}; - -struct fastd_protocol_peer_config { - aligned_int256_t public_key; -}; - -typedef struct protocol_session { - struct timespec established; - - bool handshakes_cleaned; - bool refreshing; - - const fastd_method_t *method; - fastd_method_session_state_t *method_state; -} protocol_session_t; - -struct fastd_protocol_peer_state { - protocol_session_t old_session; - protocol_session_t session; - - uint64_t last_serial; - - /* handshake cache */ - uint64_t last_handshake_serial; - aligned_int256_t peer_handshake_key; - aligned_int256_t sigma; - fastd_sha256_t shared_handshake_key; -}; - - -#define RECORD_SENDER_KEY RECORD_PROTOCOL1 -#define RECORD_RECEIPIENT_KEY RECORD_PROTOCOL2 -#define RECORD_SENDER_HANDSHAKE_KEY RECORD_PROTOCOL3 -#define RECORD_RECEIPIENT_HANDSHAKE_KEY RECORD_PROTOCOL4 -#define RECORD_T RECORD_PROTOCOL5 - - -static void send_empty(fastd_context_t *ctx, fastd_peer_t *peer, protocol_session_t *session); - - -static inline bool read_key(uint8_t key[32], const char *hexkey) { - if ((strlen(hexkey) != 64) || (strspn(hexkey, "0123456789abcdefABCDEF") != 64)) - return false; - - int i; - for (i = 0; i < 32; i++) - sscanf(&hexkey[2*i], "%02hhx", &key[i]); - - return true; -} - -static inline bool is_handshake_key_valid(fastd_context_t *ctx, const handshake_key_t *handshake_key) { - return timespec_after(&handshake_key->valid_till, &ctx->now); -} - -static inline bool is_handshake_key_preferred(fastd_context_t *ctx, const handshake_key_t *handshake_key) { - return timespec_after(&handshake_key->preferred_till, &ctx->now); -} - -static inline bool is_session_valid(fastd_context_t *ctx, const protocol_session_t *session) { - return (session->method && session->method->session_is_valid(ctx, session->method_state)); -} - -static bool backoff(fastd_context_t *ctx, const fastd_peer_t *peer) { - return (peer->protocol_state && is_session_valid(ctx, &peer->protocol_state->session) - && timespec_diff(&ctx->now, &peer->protocol_state->session.established) < 15000); -} - -static inline void check_session_refresh(fastd_context_t *ctx, fastd_peer_t *peer) { - protocol_session_t *session = &peer->protocol_state->session; - - if (!session->refreshing && session->method->session_is_initiator(ctx, session->method_state) && session->method->session_want_refresh(ctx, session->method_state)) { - pr_verbose(ctx, "refreshing session with %P", peer); - session->handshakes_cleaned = true; - session->refreshing = true; - fastd_peer_schedule_handshake(ctx, peer, 0); - } -} - -static fastd_protocol_config_t* protocol_init(fastd_context_t *ctx) { - fastd_protocol_config_t *protocol_config = malloc(sizeof(fastd_protocol_config_t)); - - if (!ctx->conf->secret) - exit_error(ctx, "no secret key configured"); - - if (!read_key(protocol_config->key.secret.p, ctx->conf->secret)) - exit_error(ctx, "invalid secret key"); - - ecc_25519_work_t work; - ecc_25519_scalarmult_base(&work, &protocol_config->key.secret); - ecc_25519_store_packed(&protocol_config->key.public, &work); - - return protocol_config; -} - -static inline void hexdump(char out[65], const unsigned char d[32]) { - int i; - for (i = 0; i < 32; i++) - snprintf(out+2*i, 3, "%02x", d[i]); -} - -static size_t key_count(fastd_context_t *ctx, const unsigned char key[32]) { - size_t ret = 0; - - fastd_peer_config_t *p; - for (p = ctx->conf->peers; p; p = p->next) { - if (!p->protocol_config) - continue; - - if (memcmp(p->protocol_config->public_key.p, key, 32) == 0) - ret++; - } - - return ret; -} - -static void protocol_peer_configure(fastd_context_t *ctx, fastd_peer_config_t *peer_conf) { - if (peer_conf->protocol_config) - return; - - if (!peer_conf->key) { - pr_warn(ctx, "no key configured for `%s', disabling peer", peer_conf->name); - return; - } - - aligned_int256_t key; - if (!read_key(key.p, peer_conf->key)) { - pr_warn(ctx, "invalid key configured for `%s', disabling peer", peer_conf->name); - return; - } - - peer_conf->protocol_config = malloc(sizeof(fastd_protocol_peer_config_t)); - peer_conf->protocol_config->public_key = key; - - if (memcmp(peer_conf->protocol_config->public_key.p, ctx->conf->protocol_config->key.public.p, 32) == 0) - pr_debug(ctx, "found own key as `%s', ignoring peer", peer_conf->name); -} - -static bool protocol_peer_check(fastd_context_t *ctx, fastd_peer_config_t *peer_conf) { - if (!peer_conf->protocol_config) - return false; - - if (memcmp(peer_conf->protocol_config->public_key.p, ctx->conf->protocol_config->key.public.p, 32) == 0) - return false; - - if (key_count(ctx, peer_conf->protocol_config->public_key.p) > 1) { - char buf[65]; - hexdump(buf, peer_conf->protocol_config->public_key.p); - pr_warn(ctx, "more than one peer is configured with key %s, disabling %s", buf, peer_conf->name); - return false; - } - - return true; -} - -static bool protocol_peer_check_temporary(fastd_context_t *ctx, fastd_peer_t *peer) { - if (key_count(ctx, peer->protocol_config->public_key.p)) { - char buf[65]; - hexdump(buf, peer->protocol_config->public_key.p); - pr_info(ctx, "key %s is configured now, deleting temporary peer.", buf); - return false; - } - - return true; -} - -static void init_protocol_state(fastd_context_t *ctx) { - if (!ctx->protocol_state) { - ctx->protocol_state = calloc(1, sizeof(fastd_protocol_state_t)); - - ctx->protocol_state->prev_handshake_key.preferred_till = ctx->conf->long_ago; - ctx->protocol_state->handshake_key.preferred_till = ctx->conf->long_ago; - } -} - -static void new_handshake_key(fastd_context_t *ctx, keypair_t *key) { - fastd_random_bytes(ctx, key->secret.p, 32, false); - ecc_25519_gf_sanitize_secret(&key->secret, &key->secret); - - ecc_25519_work_t work; - ecc_25519_scalarmult_base(&work, &key->secret); - ecc_25519_store_packed(&key->public, &work); -} - -static void maintenance(fastd_context_t *ctx) { - init_protocol_state(ctx); - - if (!is_handshake_key_preferred(ctx, &ctx->protocol_state->handshake_key)) { - pr_debug(ctx, "generating new handshake key"); - - ctx->protocol_state->prev_handshake_key = ctx->protocol_state->handshake_key; - - ctx->protocol_state->handshake_key.serial++; - - new_handshake_key(ctx, &ctx->protocol_state->handshake_key.key1); - new_handshake_key(ctx, &ctx->protocol_state->handshake_key.key2); - - ctx->protocol_state->handshake_key.preferred_till = ctx->now; - ctx->protocol_state->handshake_key.preferred_till.tv_sec += 15; - - ctx->protocol_state->handshake_key.valid_till = ctx->now; - ctx->protocol_state->handshake_key.valid_till.tv_sec += 30; - } -} - -static void protocol_handshake_init(fastd_context_t *ctx, const fastd_socket_t *sock, const fastd_peer_address_t *local_addr, const fastd_peer_address_t *remote_addr, fastd_peer_t *peer) { - maintenance(ctx); - - fastd_buffer_t buffer = fastd_handshake_new_init(ctx, 3*(4+PUBLICKEYBYTES) /* sender key, receipient key, handshake key */); - - fastd_handshake_add(ctx, &buffer, RECORD_SENDER_KEY, PUBLICKEYBYTES, ctx->conf->protocol_config->key.public.p); - - if (peer) - fastd_handshake_add(ctx, &buffer, RECORD_RECEIPIENT_KEY, PUBLICKEYBYTES, peer->protocol_config->public_key.p); - else - pr_debug(ctx, "sending handshake to unknown peer %I", remote_addr); - - fastd_handshake_add(ctx, &buffer, RECORD_SENDER_HANDSHAKE_KEY, PUBLICKEYBYTES, ctx->protocol_state->handshake_key.key1.public.p); - - fastd_send_handshake(ctx, sock, local_addr, remote_addr, peer, buffer); -} - - -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_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); - - 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->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; - - ecc_25519_scalarmult(&work, &ecc_25519_gf_order, &workX); - if (!ecc_25519_is_identity(&work)) - return false; - - if (!ecc_25519_load_packed(&work, &peer->protocol_config->public_key)) - 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 false; - - ecc_25519_store_packed(&peer->protocol_state->sigma, &work); - - 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); - - 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 UNUSED, 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, fastd_peer_t *peer, - const handshake_key_t *handshake_key, const aligned_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_buffer_t buffer = fastd_handshake_new_reply(ctx, handshake, method, true, 4*(4+PUBLICKEYBYTES) + 2*(4+HASHBYTES)); - - fastd_handshake_add(ctx, &buffer, RECORD_SENDER_KEY, PUBLICKEYBYTES, ctx->conf->protocol_config->key.public.p); - fastd_handshake_add(ctx, &buffer, RECORD_RECEIPIENT_KEY, PUBLICKEYBYTES, peer->protocol_config->public_key.p); - fastd_handshake_add(ctx, &buffer, RECORD_SENDER_HANDSHAKE_KEY, PUBLICKEYBYTES, handshake_key->key2.public.p); - fastd_handshake_add(ctx, &buffer, RECORD_RECEIPIENT_HANDSHAKE_KEY, PUBLICKEYBYTES, peer_handshake_key->p); - - fastd_sha256_t hmacbuf; - - if (!ctx->conf->secure_handshakes) { - fastd_hmacsha256_blocks(&hmacbuf, peer->protocol_state->shared_handshake_key.w, ctx->conf->protocol_config->key.public.p, handshake_key->key2.public.p, NULL); - fastd_handshake_add(ctx, &buffer, RECORD_T, HASHBYTES, hmacbuf.b); - } - - memset(&hmacbuf, 0, sizeof(hmacbuf)); - fastd_handshake_add(ctx, &buffer, RECORD_TLV_MAC, HASHBYTES, hmacbuf.b); - fastd_hmacsha256(&hmacbuf, peer->protocol_state->shared_handshake_key.w, fastd_handshake_tlv_data(&buffer), fastd_handshake_tlv_len(&buffer)); - memcpy(buffer.data+buffer.len-HASHBYTES, hmacbuf.b, HASHBYTES); - - fastd_send_handshake(ctx, sock, local_addr, remote_addr, peer, buffer); -} - -static bool establish(fastd_context_t *ctx, fastd_peer_t *peer, const fastd_method_t *method, fastd_socket_t *sock, - const fastd_peer_address_t *local_addr, const fastd_peer_address_t *remote_addr, bool initiator, - const aligned_int256_t *A, const aligned_int256_t *B, const aligned_int256_t *X, - const aligned_int256_t *Y, const aligned_int256_t *sigma, uint64_t serial) { - if (serial <= peer->protocol_state->last_serial) { - pr_debug(ctx, "ignoring handshake from %P[%I] because of handshake key reuse", peer, remote_addr); - return false; - } - - pr_verbose(ctx, "%I authorized as %P", remote_addr, peer); - - if (!fastd_peer_claim_address(ctx, peer, sock, local_addr, remote_addr)) { - pr_warn(ctx, "can't set address %I which is used by a fixed peer", remote_addr); - fastd_peer_reset(ctx, peer); - return false; - } - - if (is_session_valid(ctx, &peer->protocol_state->session) && !is_session_valid(ctx, &peer->protocol_state->old_session)) { - if (peer->protocol_state->old_session.method) - peer->protocol_state->old_session.method->session_free(ctx, peer->protocol_state->old_session.method_state); - peer->protocol_state->old_session = peer->protocol_state->session; - } - else { - if (peer->protocol_state->session.method) - peer->protocol_state->session.method->session_free(ctx, peer->protocol_state->session.method_state); - } - - if (peer->protocol_state->old_session.method) { - if (peer->protocol_state->old_session.method != method) { - pr_debug(ctx, "method of %P[%I] has changed, terminating old session", peer, remote_addr); - peer->protocol_state->old_session.method->session_free(ctx, peer->protocol_state->old_session.method_state); - peer->protocol_state->old_session = (protocol_session_t){}; - } - else { - peer->protocol_state->old_session.method->session_superseded(ctx, peer->protocol_state->old_session.method_state); - } - } - - fastd_sha256_t hash; - fastd_sha256_blocks(&hash, X->p, Y->p, A->p, B->p, sigma->p, NULL); - - peer->protocol_state->session.established = ctx->now; - peer->protocol_state->session.handshakes_cleaned = false; - peer->protocol_state->session.refreshing = false; - peer->protocol_state->session.method = method; - peer->protocol_state->session.method_state = method->session_init(ctx, hash.b, HASHBYTES, initiator); - peer->protocol_state->last_serial = serial; - - fastd_peer_seen(ctx, peer); - - fastd_peer_set_established(ctx, peer); - - pr_verbose(ctx, "new session with %P established using method `%s'.", peer, method->name); - - if (initiator) - fastd_peer_schedule_handshake_default(ctx, peer); - else - send_empty(ctx, peer, &peer->protocol_state->session); - - return true; -} - -static inline bool has_field(const fastd_handshake_t *handshake, uint8_t type, size_t length) { - return (handshake->records[type].length == length); -} - -static void finish_handshake(fastd_context_t *ctx, fastd_socket_t *sock, const fastd_peer_address_t *local_addr, const fastd_peer_address_t *remote_addr, fastd_peer_t *peer, const handshake_key_t *handshake_key, const aligned_int256_t *peer_handshake_key, - const fastd_handshake_t *handshake, const fastd_method_t *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); - - bool valid; - if (has_field(handshake, RECORD_TLV_MAC, HASHBYTES)) { - uint8_t mac[HASHBYTES]; - memcpy(mac, handshake->records[RECORD_TLV_MAC].data, HASHBYTES); - memset(handshake->records[RECORD_TLV_MAC].data, 0, HASHBYTES); - - valid = fastd_hmacsha256_verify(mac, shared_handshake_key.w, handshake->tlv_data, handshake->tlv_len); - } - else { - valid = 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 (!valid) { - pr_warn(ctx, "received invalid protocol handshake response from %P[%I]", peer, remote_addr); - return; - } - - if (!establish(ctx, peer, method, sock, local_addr, remote_addr, true, &handshake_key->key1.public, peer_handshake_key, &ctx->conf->protocol_config->key.public, - &peer->protocol_config->public_key, &sigma, handshake_key->serial)) - return; - - fastd_buffer_t buffer = fastd_handshake_new_reply(ctx, handshake, method, false, 4*(4+PUBLICKEYBYTES) + 2*(4+HASHBYTES)); - - fastd_handshake_add(ctx, &buffer, RECORD_SENDER_KEY, PUBLICKEYBYTES, ctx->conf->protocol_config->key.public.p); - fastd_handshake_add(ctx, &buffer, RECORD_RECEIPIENT_KEY, PUBLICKEYBYTES, peer->protocol_config->public_key.p); - fastd_handshake_add(ctx, &buffer, RECORD_SENDER_HANDSHAKE_KEY, PUBLICKEYBYTES, handshake_key->key1.public.p); - fastd_handshake_add(ctx, &buffer, RECORD_RECEIPIENT_HANDSHAKE_KEY, PUBLICKEYBYTES, peer_handshake_key->p); - - fastd_sha256_t hmacbuf; - - if (!ctx->conf->secure_handshakes) { - fastd_hmacsha256_blocks(&hmacbuf, shared_handshake_key.w, ctx->conf->protocol_config->key.public.p, handshake_key->key1.public.p, NULL); - fastd_handshake_add(ctx, &buffer, RECORD_T, HASHBYTES, hmacbuf.b); - } - - memset(&hmacbuf, 0, sizeof(hmacbuf)); - fastd_handshake_add(ctx, &buffer, RECORD_TLV_MAC, HASHBYTES, hmacbuf.b); - fastd_hmacsha256(&hmacbuf, shared_handshake_key.w, fastd_handshake_tlv_data(&buffer), fastd_handshake_tlv_len(&buffer)); - memcpy(buffer.data+buffer.len-HASHBYTES, hmacbuf.b, HASHBYTES); - - fastd_send_handshake(ctx, sock, local_addr, remote_addr, peer, buffer); -} - -static void handle_finish_handshake(fastd_context_t *ctx, fastd_socket_t *sock, const fastd_peer_address_t *local_addr, const fastd_peer_address_t *remote_addr, - fastd_peer_t *peer, const handshake_key_t *handshake_key, const aligned_int256_t *peer_handshake_key, - const fastd_handshake_t *handshake, const fastd_method_t *method) { - pr_debug(ctx, "handling handshake finish with %P[%I]...", peer, remote_addr); - - if (!update_shared_handshake_key(ctx, peer, handshake_key, peer_handshake_key)) - return; - - bool valid; - if (has_field(handshake, RECORD_TLV_MAC, HASHBYTES)) { - uint8_t mac[HASHBYTES]; - memcpy(mac, handshake->records[RECORD_TLV_MAC].data, HASHBYTES); - memset(handshake->records[RECORD_TLV_MAC].data, 0, HASHBYTES); - - valid = fastd_hmacsha256_verify(mac, peer->protocol_state->shared_handshake_key.w, handshake->tlv_data, handshake->tlv_len); - } - else { - valid = 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); - } - - if (!valid) { - 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->key2.public, &peer->protocol_config->public_key, - &ctx->conf->protocol_config->key.public, &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) { - errno = 0; - - fastd_peer_t *ret = NULL, *peer; - - for (peer = peers; peer; peer = peer->next) { - if (memcmp(peer->protocol_config->public_key.p, key, PUBLICKEYBYTES) == 0) { - if (!fastd_peer_matches_address(ctx, peer, address)) { - errno = EPERM; - return NULL; - } - - ret = peer; - continue; - } - - if (fastd_peer_owns_address(ctx, peer, address)) { - errno = EPERM; - return NULL; - } - } - - if (!ret) - errno = ENOENT; - - return ret; -} - -static fastd_peer_t* match_sender_key(fastd_context_t *ctx, const fastd_socket_t *sock, const fastd_peer_address_t *address, fastd_peer_t *peer, const unsigned char key[32]) { - errno = 0; - - if (sock->peer && peer != sock->peer) - exit_bug(ctx, "packet without correct peer set on dynamic socket"); - - if (peer) { - if (memcmp(peer->protocol_config->public_key.p, key, PUBLICKEYBYTES) == 0) - return peer; - - if (fastd_peer_owns_address(ctx, peer, address)) { - errno = EPERM; - return NULL; - } - } - - peer = find_sender_key(ctx, address, key, ctx->peers); - - if (!peer && errno == ENOENT) - peer = find_sender_key(ctx, address, key, ctx->peers_temp); - - return peer; -} - -static inline fastd_peer_t* add_temporary(fastd_context_t *ctx, const fastd_peer_address_t *local_addr, const fastd_peer_address_t *remote_addr, const unsigned char key[32]) { - if (!fastd_peer_allow_unknown(ctx)) { - pr_debug(ctx, "ignoring handshake from %I (unknown key)", remote_addr); - return NULL; - } - - if (key_count(ctx, key)) { - pr_debug(ctx, "ignoring handshake from %I (disabled key)", remote_addr); - return NULL; - } - - fastd_peer_t *peer = fastd_peer_add_temporary(ctx); - - peer->protocol_config = malloc(sizeof(fastd_protocol_peer_config_t)); - memcpy(peer->protocol_config->public_key.p, key, PUBLICKEYBYTES); - - /* Ugly hack */ - peer->protocol_state->last_serial--; - - if (!fastd_peer_verify_temporary(ctx, peer, local_addr, remote_addr)) { - pr_debug(ctx, "ignoring handshake from %P[%I] (verification failed)", peer, remote_addr); - fastd_peer_delete(ctx, peer); - return NULL; - } - - return peer; -} - -static inline keypair_t* get_handshake_keypair(handshake_key_t *handshake_key, uint8_t type) { - return (type % 2) ? &handshake_key->key2 : &handshake_key->key1; -} - -static void protocol_handshake_handle(fastd_context_t *ctx, fastd_socket_t *sock, const fastd_peer_address_t *local_addr, const fastd_peer_address_t *remote_addr, fastd_peer_t *peer, const fastd_handshake_t *handshake, const fastd_method_t *method) { - bool temporary_added = false; - - maintenance(ctx); - - if (!has_field(handshake, RECORD_SENDER_KEY, PUBLICKEYBYTES)) { - pr_debug(ctx, "received handshake without sender key from %I", remote_addr); - return; - } - - peer = match_sender_key(ctx, sock, remote_addr, peer, handshake->records[RECORD_SENDER_KEY].data); - if (!peer) { - switch (errno) { - case EPERM: - pr_debug(ctx, "ignoring handshake from %I (incorrect source address)", remote_addr); - return; - - case ENOENT: - peer = add_temporary(ctx, local_addr, remote_addr, handshake->records[RECORD_SENDER_KEY].data); - if (peer) { - temporary_added = true; - break; - } - - return; - - default: - exit_bug(ctx, "match_sender_key: unknown error"); - } - } - - if (fastd_peer_is_temporary(peer) && !temporary_added) { - if (!fastd_peer_verify_temporary(ctx, peer, local_addr, remote_addr)) { - pr_debug(ctx, "ignoring handshake from %P[%I] (verification failed)", peer, remote_addr); - return; - } - } - - if (!fastd_peer_may_connect(ctx, peer)) { - pr_debug(ctx, "ignoring handshake from %P[%I] because of local constraints", peer, remote_addr); - return; - } - - if (backoff(ctx, peer)) { - pr_debug(ctx, "received repeated handshakes from %P[%I], ignoring", peer, remote_addr); - return; - } - - if (has_field(handshake, RECORD_RECEIPIENT_KEY, PUBLICKEYBYTES)) { - if (memcmp(ctx->conf->protocol_config->key.public.p, handshake->records[RECORD_RECEIPIENT_KEY].data, PUBLICKEYBYTES) != 0) { - pr_debug(ctx, "received protocol handshake with wrong receipient key from %P[%I]", peer, remote_addr); - return; - } - } - - if (!has_field(handshake, RECORD_SENDER_HANDSHAKE_KEY, PUBLICKEYBYTES)) { - pr_debug(ctx, "received handshake without sender handshake key from %P[%I]", peer, remote_addr); - return; - } - - aligned_int256_t peer_handshake_key; - memcpy(peer_handshake_key.p, handshake->records[RECORD_SENDER_HANDSHAKE_KEY].data, PUBLICKEYBYTES); - - if (handshake->type == 1) { - if (timespec_diff(&ctx->now, &peer->last_handshake_response) < (int)ctx->conf->min_handshake_interval*1000 - && fastd_peer_address_equal(remote_addr, &peer->last_handshake_response_address)) { - pr_debug(ctx, "not responding repeated handshake from %P[%I]", peer, remote_addr); - return; - } - - pr_verbose(ctx, "received handshake from %P[%I]%s%s", peer, remote_addr, handshake->peer_version ? " using fastd " : "", handshake->peer_version ?: ""); - - peer->last_handshake_response = ctx->now; - peer->last_handshake_response_address = *remote_addr; - respond_handshake(ctx, sock, local_addr, remote_addr, peer, &ctx->protocol_state->handshake_key, &peer_handshake_key, handshake, method); - return; - } - - if (!has_field(handshake, RECORD_RECEIPIENT_KEY, PUBLICKEYBYTES)) { - pr_debug(ctx, "received handshake reply without receipient key from %P[%I]", peer, remote_addr); - return; - } - - if (!has_field(handshake, RECORD_RECEIPIENT_HANDSHAKE_KEY, PUBLICKEYBYTES)) { - pr_debug(ctx, "received handshake reply without receipient handshake key from %P[%I]", peer, remote_addr); - return; - } - - if (!has_field(handshake, RECORD_TLV_MAC, HASHBYTES)) { - if (ctx->conf->secure_handshakes || !has_field(handshake, RECORD_T, HASHBYTES)) { - pr_debug(ctx, "received handshake reply without HMAC from %P[%I]", peer, remote_addr); - return; - } - } - - handshake_key_t *handshake_key; - if (is_handshake_key_valid(ctx, &ctx->protocol_state->handshake_key) && - memcmp(get_handshake_keypair(&ctx->protocol_state->handshake_key, handshake->type)->public.p, handshake->records[RECORD_RECEIPIENT_HANDSHAKE_KEY].data, PUBLICKEYBYTES) == 0) { - handshake_key = &ctx->protocol_state->handshake_key; - } - else if (is_handshake_key_valid(ctx, &ctx->protocol_state->prev_handshake_key) && - memcmp(get_handshake_keypair(&ctx->protocol_state->prev_handshake_key, handshake->type)->public.p, handshake->records[RECORD_RECEIPIENT_HANDSHAKE_KEY].data, PUBLICKEYBYTES) == 0) { - handshake_key = &ctx->protocol_state->prev_handshake_key; - } - else { - pr_debug(ctx, "received handshake reply with unexpected receipient handshake key from %P[%I]", peer, remote_addr); - return; - } - - switch (handshake->type) { - case 2: - pr_verbose(ctx, "received handshake response from %P[%I]%s%s", peer, remote_addr, handshake->peer_version ? " using fastd " : "", handshake->peer_version ?: ""); - - finish_handshake(ctx, sock, local_addr, remote_addr, peer, handshake_key, &peer_handshake_key, handshake, method); - break; - - case 3: - pr_debug(ctx, "received handshake finish from %P[%I]%s%s", peer, remote_addr, handshake->peer_version ? " using fastd " : "", handshake->peer_version ?: ""); - - handle_finish_handshake(ctx, sock, local_addr, remote_addr, peer, handshake_key, &peer_handshake_key, handshake, method); - break; - - default: - pr_debug(ctx, "received handshake reply with unknown type %u from %P[%I]", handshake->type, peer, remote_addr); - } -} - -static inline bool check_session(fastd_context_t *ctx, fastd_peer_t *peer) { - if (is_session_valid(ctx, &peer->protocol_state->session)) - return true; - - pr_verbose(ctx, "active session with %P timed out", peer); - fastd_peer_reset(ctx, peer); - return false; -} - -static void protocol_handle_recv(fastd_context_t *ctx, fastd_peer_t *peer, fastd_buffer_t buffer) { - if (!peer->protocol_state || !check_session(ctx, peer)) - goto fail; - - fastd_buffer_t recv_buffer; - bool ok = false; - - if (is_session_valid(ctx, &peer->protocol_state->old_session)) { - if (peer->protocol_state->old_session.method->decrypt(ctx, peer, peer->protocol_state->old_session.method_state, &recv_buffer, buffer)) - ok = true; - } - - if (!ok) { - if (peer->protocol_state->session.method->decrypt(ctx, peer, peer->protocol_state->session.method_state, &recv_buffer, buffer)) { - ok = true; - - if (peer->protocol_state->old_session.method) { - pr_debug(ctx, "invalidating old session with %P", peer); - peer->protocol_state->old_session.method->session_free(ctx, peer->protocol_state->old_session.method_state); - peer->protocol_state->old_session = (protocol_session_t){}; - } - - if (!peer->protocol_state->session.handshakes_cleaned) { - pr_debug(ctx, "cleaning left handshakes with %P", peer); - fastd_peer_unschedule_handshake(ctx, peer); - peer->protocol_state->session.handshakes_cleaned = true; - - if (peer->protocol_state->session.method->session_is_initiator(ctx, peer->protocol_state->session.method_state)) - send_empty(ctx, peer, &peer->protocol_state->session); - } - - check_session_refresh(ctx, peer); - } - } - - if (!ok) { - pr_verbose(ctx, "verification failed for packet received from %P", peer); - goto fail; - } - - fastd_peer_seen(ctx, peer); - - if (recv_buffer.len) - fastd_handle_receive(ctx, peer, recv_buffer); - else - fastd_buffer_free(recv_buffer); - - return; - - fail: - fastd_buffer_free(buffer); -} - -static void session_send(fastd_context_t *ctx, fastd_peer_t *peer, fastd_buffer_t buffer, protocol_session_t *session) { - size_t stat_size = buffer.len; - - fastd_buffer_t send_buffer; - if (!session->method->encrypt(ctx, peer, session->method_state, &send_buffer, buffer)) { - fastd_buffer_free(buffer); - return; - } - - fastd_send(ctx, peer->sock, &peer->local_address, &peer->address, peer, send_buffer, stat_size); - peer->last_send = ctx->now; -} - -static void protocol_send(fastd_context_t *ctx, fastd_peer_t *peer, fastd_buffer_t buffer) { - if (!peer->protocol_state || !fastd_peer_is_established(peer) || !check_session(ctx, peer)) { - fastd_buffer_free(buffer); - return; - } - - check_session_refresh(ctx, peer); - - if (peer->protocol_state->session.method->session_is_initiator(ctx, peer->protocol_state->session.method_state) && is_session_valid(ctx, &peer->protocol_state->old_session)) { - pr_debug2(ctx, "sending packet for old session to %P", peer); - session_send(ctx, peer, buffer, &peer->protocol_state->old_session); - } - else { - session_send(ctx, peer, buffer, &peer->protocol_state->session); - } -} - -static void send_empty(fastd_context_t *ctx, fastd_peer_t *peer, protocol_session_t *session) { - session_send(ctx, peer, fastd_buffer_alloc(ctx, 0, alignto(session->method->min_encrypt_head_space(ctx), 8), session->method->min_encrypt_tail_space(ctx)), session); -} - -static void protocol_init_peer_state(fastd_context_t *ctx, fastd_peer_t *peer) { - init_protocol_state(ctx); - - if (peer->protocol_state) - exit_bug(ctx, "tried to reinit peer state"); - - peer->protocol_state = calloc(1, sizeof(fastd_protocol_peer_state_t)); - peer->protocol_state->last_serial = ctx->protocol_state->handshake_key.serial; -} - -static void reset_session(fastd_context_t *ctx, protocol_session_t *session) { - if (session->method) - session->method->session_free(ctx, session->method_state); - secure_memzero(session, sizeof(protocol_session_t)); -} - -static void protocol_reset_peer_state(fastd_context_t *ctx, fastd_peer_t *peer) { - if (!peer->protocol_state) - return; - - reset_session(ctx, &peer->protocol_state->old_session); - reset_session(ctx, &peer->protocol_state->session); -} - -static void protocol_free_peer_state(fastd_context_t *ctx, fastd_peer_t *peer) { - if (peer->protocol_state) { - reset_session(ctx, &peer->protocol_state->old_session); - reset_session(ctx, &peer->protocol_state->session); - - free(peer->protocol_state); - } -} - -static inline void print_hexdump(const char *desc, unsigned char d[32]) { - char buf[65]; - hexdump(buf, d); - - printf("%s%s\n", desc, buf); -} - -static void protocol_generate_key(fastd_context_t *ctx) { - ecc_int256_t secret_key; - ecc_int256_t public_key; - - if (!ctx->conf->machine_readable) - pr_info(ctx, "Reading 32 bytes from /dev/random..."); - - fastd_random_bytes(ctx, secret_key.p, 32, true); - ecc_25519_gf_sanitize_secret(&secret_key, &secret_key); - - ecc_25519_work_t work; - ecc_25519_scalarmult_base(&work, &secret_key); - ecc_25519_store_packed(&public_key, &work); - - if (ctx->conf->machine_readable) { - print_hexdump("", secret_key.p); - } - else { - print_hexdump("Secret: ", secret_key.p); - print_hexdump("Public: ", public_key.p); - } -} - -static void protocol_show_key(fastd_context_t *ctx) { - if (ctx->conf->machine_readable) - print_hexdump("", ctx->conf->protocol_config->key.public.p); - else - print_hexdump("Public: ", ctx->conf->protocol_config->key.public.p); -} - -static void protocol_set_shell_env(fastd_context_t *ctx, const fastd_peer_t *peer) { - char buf[65]; - - hexdump(buf, ctx->conf->protocol_config->key.public.p); - setenv("LOCAL_KEY", buf, 1); - - if (peer && peer->protocol_config) { - hexdump(buf, peer->protocol_config->public_key.p); - setenv("PEER_KEY", buf, 1); - } - else { - unsetenv("PEER_KEY"); - } -} - -static bool protocol_describe_peer(const fastd_context_t *ctx UNUSED, const fastd_peer_t *peer, char *buf, size_t len) { - if (peer && peer->protocol_config) { - char dumpbuf[65]; - - hexdump(dumpbuf, peer->protocol_config->public_key.p); - snprintf(buf, len, "%.16s", dumpbuf); - return true; - } - else { - return false; - } -} - -const fastd_protocol_t fastd_protocol_ec25519_fhmqvc = { - .name = "ec25519-fhmqvc", - - .init = protocol_init, - .peer_configure = protocol_peer_configure, - .peer_check = protocol_peer_check, - .peer_check_temporary = protocol_peer_check_temporary, - - .handshake_init = protocol_handshake_init, - .handshake_handle = protocol_handshake_handle, - - .handle_recv = protocol_handle_recv, - .send = protocol_send, - - .init_peer_state = protocol_init_peer_state, - .reset_peer_state = protocol_reset_peer_state, - .free_peer_state = protocol_free_peer_state, - - .generate_key = protocol_generate_key, - .show_key = protocol_show_key, - .set_shell_env = protocol_set_shell_env, - .describe_peer = protocol_describe_peer, -}; |