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-rw-r--r--src/handshake.c7
-rw-r--r--src/handshake.h4
-rw-r--r--src/protocol_ec25519_fhmqvc.c80
3 files changed, 67 insertions, 24 deletions
diff --git a/src/handshake.c b/src/handshake.c
index 5400828..8447b3f 100644
--- a/src/handshake.c
+++ b/src/handshake.c
@@ -45,6 +45,7 @@ static const char *const RECORD_TYPES[RECORD_MAX] = {
"method name",
"version name",
"method list",
+ "handshake message authentication code",
};
static const char *const REPLY_TYPES[REPLY_MAX] = {
@@ -140,7 +141,7 @@ fastd_buffer_t fastd_handshake_new_reply(fastd_context_t *ctx, const fastd_hands
extra_size = 6 + /* MTU */
4+version_len; /* version name */
- fastd_buffer_t buffer = fastd_buffer_alloc(ctx, sizeof(fastd_packet_t), 0,
+ fastd_buffer_t buffer = fastd_buffer_alloc(ctx, sizeof(fastd_packet_t), 1,
2*5 + /* handshake type, reply code */
4+method_len + /* method name */
extra_size +
@@ -183,9 +184,7 @@ void fastd_handshake_handle(fastd_context_t *ctx, fastd_socket_t *sock, const fa
goto end_free;
}
- fastd_handshake_t handshake;
- memset(&handshake, 0, sizeof(handshake));
-
+ fastd_handshake_t handshake = { .buffer = buffer };
fastd_packet_t *packet = buffer.data;
uint8_t *ptr = packet->tlv_data;
diff --git a/src/handshake.h b/src/handshake.h
index 70a1c6c..6415d5e 100644
--- a/src/handshake.h
+++ b/src/handshake.h
@@ -46,6 +46,7 @@ typedef enum fastd_handshake_record_type {
RECORD_METHOD_NAME,
RECORD_VERSION_NAME,
RECORD_METHOD_LIST,
+ RECORD_HANDSHAKE_MAC,
RECORD_MAX,
} fastd_handshake_record_type_t;
@@ -59,12 +60,13 @@ typedef enum fastd_reply_code {
typedef struct fastd_handshake_record {
size_t length;
- const uint8_t *data;
+ uint8_t *data;
} fastd_handshake_record_t;
struct fastd_handshake {
uint8_t type;
fastd_handshake_record_t records[RECORD_MAX];
+ fastd_buffer_t buffer;
};
diff --git a/src/protocol_ec25519_fhmqvc.c b/src/protocol_ec25519_fhmqvc.c
index ad65ca7..622f633 100644
--- a/src/protocol_ec25519_fhmqvc.c
+++ b/src/protocol_ec25519_fhmqvc.c
@@ -370,16 +370,24 @@ static void respond_handshake(fastd_context_t *ctx, const fastd_socket_t *sock,
if (!update_shared_handshake_key(ctx, peer, handshake_key, peer_handshake_key))
return;
- fastd_sha256_t hmacbuf;
- 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_buffer_t buffer = fastd_handshake_new_reply(ctx, handshake, method, 4*(4+PUBLICKEYBYTES) + 4+HASHBYTES);
+ fastd_buffer_t buffer = fastd_handshake_new_reply(ctx, handshake, method, 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_handshake_add(ctx, &buffer, RECORD_T, HASHBYTES, hmacbuf.b);
+
+ 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_HANDSHAKE_MAC, HASHBYTES, hmacbuf.b);
+ fastd_hmacsha256(&hmacbuf, peer->protocol_state->shared_handshake_key.w, buffer.data+3, buffer.len-3);
+ memcpy(buffer.data+buffer.len-HASHBYTES, hmacbuf.b, HASHBYTES);
fastd_send_handshake(ctx, sock, local_addr, remote_addr, peer, buffer);
}
@@ -446,6 +454,10 @@ static bool establish(fastd_context_t *ctx, fastd_peer_t *peer, const fastd_meth
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);
@@ -499,25 +511,45 @@ static void finish_handshake(fastd_context_t *ctx, fastd_socket_t *sock, const f
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)) {
+ bool valid;
+ if (has_field(handshake, RECORD_HANDSHAKE_MAC, HASHBYTES)) {
+ uint8_t mac[HASHBYTES];
+ memcpy(mac, handshake->records[RECORD_HANDSHAKE_MAC].data, HASHBYTES);
+ memset(handshake->records[RECORD_HANDSHAKE_MAC].data, 0, HASHBYTES);
+
+ valid = fastd_hmacsha256_verify(mac, shared_handshake_key.w, handshake->buffer.data+3, handshake->buffer.len-3);
+ }
+ 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;
}
- fastd_sha256_t hmacbuf;
- fastd_hmacsha256_blocks(&hmacbuf, shared_handshake_key.w, ctx->conf->protocol_config->key.public.p, handshake_key->key1.public.p, NULL);
-
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, 4*(4+PUBLICKEYBYTES) + 4+HASHBYTES);
+ fastd_buffer_t buffer = fastd_handshake_new_reply(ctx, handshake, method, 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_handshake_add(ctx, &buffer, RECORD_T, HASHBYTES, hmacbuf.b);
+
+ 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_HANDSHAKE_MAC, HASHBYTES, hmacbuf.b);
+ fastd_hmacsha256(&hmacbuf, shared_handshake_key.w, buffer.data+3, buffer.len-3);
+ memcpy(buffer.data+buffer.len-HASHBYTES, hmacbuf.b, HASHBYTES);
fastd_send_handshake(ctx, sock, local_addr, remote_addr, peer, buffer);
}
@@ -530,7 +562,19 @@ static void handle_finish_handshake(fastd_context_t *ctx, fastd_socket_t *sock,
if (!update_shared_handshake_key(ctx, peer, handshake_key, peer_handshake_key))
return;
- 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)) {
+ bool valid;
+ if (has_field(handshake, RECORD_HANDSHAKE_MAC, HASHBYTES)) {
+ uint8_t mac[HASHBYTES];
+ memcpy(mac, handshake->records[RECORD_HANDSHAKE_MAC].data, HASHBYTES);
+ memset(handshake->records[RECORD_HANDSHAKE_MAC].data, 0, HASHBYTES);
+
+ valid = fastd_hmacsha256_verify(mac, peer->protocol_state->shared_handshake_key.w, handshake->buffer.data+3, handshake->buffer.len-3);
+ }
+ 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;
}
@@ -593,10 +637,6 @@ static fastd_peer_t* match_sender_key(fastd_context_t *ctx, const fastd_socket_t
return peer;
}
-static inline bool has_field(const fastd_handshake_t *handshake, uint8_t type, size_t length) {
- return (handshake->records[type].length == length);
-}
-
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);
@@ -722,9 +762,11 @@ static void protocol_handshake_handle(fastd_context_t *ctx, fastd_socket_t *sock
return;
}
- if (!has_field(handshake, RECORD_T, HASHBYTES)) {
- pr_debug(ctx, "received handshake reply without HMAC from %P[%I]", peer, remote_addr);
- return;
+ if (!has_field(handshake, RECORD_HANDSHAKE_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;
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-26 09:21:44 +0100