From 18a3a6468ede6463a7ca2582ca1199af37099eb4 Mon Sep 17 00:00:00 2001 From: Matthias Schiffer Date: Sat, 19 Oct 2013 17:57:23 +0200 Subject: Authenticate the TLV records only --- src/handshake.c | 4 ++-- src/handshake.h | 15 +++++++++++++-- src/protocol_ec25519_fhmqvc.c | 8 ++++---- 3 files changed, 19 insertions(+), 8 deletions(-) diff --git a/src/handshake.c b/src/handshake.c index 82d47b8..962daa0 100644 --- a/src/handshake.c +++ b/src/handshake.c @@ -183,12 +183,11 @@ void fastd_handshake_handle(fastd_context_t *ctx, fastd_socket_t *sock, const fa goto end_free; } - fastd_handshake_t handshake = { .buffer = buffer }; fastd_handshake_packet_t *packet = buffer.data; size_t len = buffer.len - sizeof(fastd_handshake_packet_t); if (packet->tlv_len) { - size_t tlv_len = ntohs(packet->tlv_len); + size_t tlv_len = fastd_handshake_tlv_len(&buffer); if (tlv_len > len) { pr_warn(ctx, "received a short handshake from %I", remote_addr); goto end_free; @@ -198,6 +197,7 @@ void fastd_handshake_handle(fastd_context_t *ctx, fastd_socket_t *sock, const fa } uint8_t *ptr = packet->tlv_data, *end = packet->tlv_data + len; + fastd_handshake_t handshake = { .tlv_len = len, .tlv_data = packet->tlv_data }; while (true) { if (ptr+4 > end) diff --git a/src/handshake.h b/src/handshake.h index e548be3..c25d427 100644 --- a/src/handshake.h +++ b/src/handshake.h @@ -72,7 +72,8 @@ typedef struct fastd_handshake_record { struct fastd_handshake { uint8_t type; fastd_handshake_record_t records[RECORD_MAX]; - fastd_buffer_t buffer; + uint16_t tlv_len; + void *tlv_data; }; @@ -82,6 +83,16 @@ fastd_buffer_t fastd_handshake_new_reply(fastd_context_t *ctx, const fastd_hands void fastd_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, fastd_buffer_t buffer); +static inline void* fastd_handshake_tlv_data(const fastd_buffer_t *buffer) { + fastd_handshake_packet_t *packet = buffer->data; + return packet->tlv_data; +} + +static inline uint16_t fastd_handshake_tlv_len(const fastd_buffer_t *buffer) { + fastd_handshake_packet_t *packet = buffer->data; + return ntohs(packet->tlv_len); +} + static inline uint8_t* fastd_handshake_extend(fastd_context_t *ctx, fastd_buffer_t *buffer, fastd_handshake_record_type_t type, size_t len) { uint8_t *dst = buffer->data + buffer->len; @@ -91,7 +102,7 @@ static inline uint8_t* fastd_handshake_extend(fastd_context_t *ctx, fastd_buffer buffer->len += 4 + len; fastd_handshake_packet_t *packet = buffer->data; - packet->tlv_len = htons(ntohs(packet->tlv_len) + 4 + len); + packet->tlv_len = htons(fastd_handshake_tlv_len(buffer) + 4 + len); dst[0] = type; dst[1] = type >> 8; diff --git a/src/protocol_ec25519_fhmqvc.c b/src/protocol_ec25519_fhmqvc.c index c3419d5..5f13244 100644 --- a/src/protocol_ec25519_fhmqvc.c +++ b/src/protocol_ec25519_fhmqvc.c @@ -386,7 +386,7 @@ static void respond_handshake(fastd_context_t *ctx, const fastd_socket_t *sock, 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+sizeof(fastd_handshake_packet_t), buffer.len-sizeof(fastd_handshake_packet_t)); + 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); @@ -517,7 +517,7 @@ static void finish_handshake(fastd_context_t *ctx, fastd_socket_t *sock, const f 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+sizeof(fastd_handshake_packet_t), handshake->buffer.len-sizeof(fastd_handshake_packet_t)); + 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); @@ -548,7 +548,7 @@ static void finish_handshake(fastd_context_t *ctx, fastd_socket_t *sock, const f 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+sizeof(fastd_handshake_packet_t), buffer.len-sizeof(fastd_handshake_packet_t)); + 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); @@ -568,7 +568,7 @@ static void handle_finish_handshake(fastd_context_t *ctx, fastd_socket_t *sock, 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+sizeof(fastd_handshake_packet_t), handshake->buffer.len-sizeof(fastd_handshake_packet_t)); + 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); -- cgit v1.2.3