From c8ba23bcec94ecbc8ee82053d1b7e299cc839184 Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Wed, 18 Jan 2017 06:45:50 +0100 Subject: tls: massage writing for encryption support; finer-grained debug Signed-off-by: Denys Vlasenko --- networking/tls.c | 69 +++++++++++++++++++++++++++++++------------------------- 1 file changed, 38 insertions(+), 31 deletions(-) (limited to 'networking/tls.c') diff --git a/networking/tls.c b/networking/tls.c index 8bcaee9a6..9d1a0fca9 100644 --- a/networking/tls.c +++ b/networking/tls.c @@ -25,7 +25,9 @@ #include "tls.h" -#define TLS_DEBUG 2 +#define TLS_DEBUG 1 +#define TLS_DEBUG_HASH 0 +#define TLS_DEBUG_DER 0 #if TLS_DEBUG # define dbg(...) fprintf(stderr, __VA_ARGS__) @@ -33,6 +35,12 @@ # define dbg(...) ((void)0) #endif +#if TLS_DEBUG_DER +# define dbg_der(...) fprintf(stderr, __VA_ARGS__) +#else +# define dbg_der(...) ((void)0) +#endif + #define RECORD_TYPE_CHANGE_CIPHER_SPEC 20 #define RECORD_TYPE_ALERT 21 #define RECORD_TYPE_HANDSHAKE 22 @@ -269,7 +277,7 @@ static void sha256_peek(sha256_ctx_t *ctx, void *buffer) sha256_end(&ctx_copy, buffer); } -#if TLS_DEBUG >= 2 +#if TLS_DEBUG_HASH static void sha256_hash_dbg(const char *fmt, sha256_ctx_t *ctx, const void *buffer, size_t len) { uint8_t h[SHA256_OUTSIZE]; @@ -283,7 +291,7 @@ static void sha256_hash_dbg(const char *fmt, sha256_ctx_t *ctx, const void *buff #else # define sha256_hash_dbg(fmt, ctx, buffer, len) \ sha256_hash(ctx, buffer, len) -#endif /* not TLS_DEBUG >= 2 */ +#endif // RFC 2104 // HMAC(key, text) based on a hash H (say, sha256) is: @@ -424,8 +432,7 @@ static void prf_hmac_sha256( #undef SEED } -static -tls_state_t *new_tls_state(void) +static tls_state_t *new_tls_state(void) { tls_state_t *tls = xzalloc(sizeof(*tls)); tls->fd = -1; @@ -488,31 +495,31 @@ static void xwrite_and_hash(tls_state_t *tls, /*const*/ void *buf, unsigned size uint8_t mac_hash[SHA256_OUTSIZE]; struct record_hdr *xhdr = buf; - if (tls->encrypt_on_write) { + if (!tls->encrypt_on_write) { + xwrite(tls->fd, buf, size); + dbg("wrote %u bytes\n", size); + /* Handshake hash does not include record headers */ + if (size > 5 && xhdr->type == RECORD_TYPE_HANDSHAKE) { + sha256_hash_dbg(">> sha256:%s", &tls->handshake_sha256_ctx, (uint8_t*)buf + 5, size - 5); + } + return; + } + //TODO: convert hmac_sha256 to precomputed - hmac_sha256(mac_hash, + hmac_sha256(mac_hash, tls->client_write_MAC_key, sizeof(tls->client_write_MAC_key), &tls->write_seq64_be, sizeof(tls->write_seq64_be), buf, size, - NULL); - tls->write_seq64_be = SWAP_BE64(1 + SWAP_BE64(tls->write_seq64_be)); - /* Temporarily change for writing */ - xhdr->len16_lo += SHA256_OUTSIZE; - } + NULL); + tls->write_seq64_be = SWAP_BE64(1 + SWAP_BE64(tls->write_seq64_be)); + xhdr->len16_lo += SHA256_OUTSIZE; xwrite(tls->fd, buf, size); + xhdr->len16_lo -= SHA256_OUTSIZE; dbg("wrote %u bytes\n", size); - if (tls->encrypt_on_write) { - xwrite(tls->fd, mac_hash, sizeof(mac_hash)); - dbg("wrote %u bytes of hash\n", (int)sizeof(mac_hash)); - xhdr->len16_lo -= SHA256_OUTSIZE; - } - - /* Handshake hash does not include record headers */ - if (size > 5 && xhdr->type == RECORD_TYPE_HANDSHAKE) { - sha256_hash_dbg(">> sha256:%s", &tls->handshake_sha256_ctx, (uint8_t*)buf + 5, size - 5); - } + xwrite(tls->fd, mac_hash, sizeof(mac_hash)); + dbg("wrote %u bytes of hash\n", (int)sizeof(mac_hash)); } static int xread_tls_block(tls_state_t *tls) @@ -611,7 +618,7 @@ static uint8_t *enter_der_item(uint8_t *der, uint8_t **endp) { uint8_t *new_der; unsigned len = get_der_len(&new_der, der, *endp); - dbg("entered der @%p:0x%02x len:%u inner_byte @%p:0x%02x\n", der, der[0], len, new_der, new_der[0]); + dbg_der("entered der @%p:0x%02x len:%u inner_byte @%p:0x%02x\n", der, der[0], len, new_der, new_der[0]); /* Move "end" position to cover only this item */ *endp = new_der + len; return new_der; @@ -623,7 +630,7 @@ static uint8_t *skip_der_item(uint8_t *der, uint8_t *end) unsigned len = get_der_len(&new_der, der, end); /* Skip body */ new_der += len; - dbg("skipped der 0x%02x, next byte 0x%02x\n", der[0], new_der[0]); + dbg_der("skipped der 0x%02x, next byte 0x%02x\n", der[0], new_der[0]); return new_der; } @@ -632,7 +639,7 @@ static void der_binary_to_pstm(pstm_int *pstm_n, uint8_t *der, uint8_t *end) uint8_t *bin_ptr; unsigned len = get_der_len(&bin_ptr, der, end); - dbg("binary bytes:%u, first:0x%02x\n", len, bin_ptr[0]); + dbg_der("binary bytes:%u, first:0x%02x\n", len, bin_ptr[0]); pstm_init_for_read_unsigned_bin(/*pool:*/ NULL, pstm_n, len); pstm_read_unsigned_bin(pstm_n, bin_ptr, len); //return bin + len; @@ -854,7 +861,7 @@ static void send_client_hello(tls_state_t *tls) /* record.comprtypes[0] = 0; */ //dbg (make it repeatable): memset(record.rand32, 0x11, sizeof(record.rand32)); - dbg(">> HANDSHAKE_CLIENT_HELLO\n"); + dbg(">> CLIENT_HELLO\n"); xwrite_and_hash(tls, &record, sizeof(record)); memcpy(tls->client_and_server_rand32, record.rand32, sizeof(record.rand32)); } @@ -988,7 +995,7 @@ static void send_client_key_exchange(tls_state_t *tls) record.xhdr.len16_hi = len >> 8; record.xhdr.len16_lo = len & 0xff; - dbg(">> HANDSHAKE_CLIENT_KEY_EXCHANGE\n"); + dbg(">> CLIENT_KEY_EXCHANGE\n"); xwrite_and_hash(tls, &record, sizeof(record.xhdr) + len); // RFC 5246 @@ -1114,13 +1121,13 @@ static void send_change_cipher_spec(tls_state_t *tls) // includes all existing cipher suites. static void send_client_finished(tls_state_t *tls) { - struct client_finished { + struct finished { struct record_hdr xhdr; uint8_t type; uint8_t len24_hi, len24_mid, len24_lo; uint8_t prf_result[12]; }; - struct client_finished record; + struct finished record; uint8_t handshake_hash[SHA256_OUTSIZE]; fill_handshake_record_hdr(&record.xhdr, sizeof(record)); @@ -1134,13 +1141,13 @@ static void send_client_finished(tls_state_t *tls) ); dump_hex("from secret: %s\n", tls->master_secret, sizeof(tls->master_secret)); dump_hex("from labelSeed: %s", "client finished", sizeof("client finished")-1); - dump_hex("%s\n", handshake_hash, sizeof(handshake_hash)); + dump_hex("%s\n", handshake_hash, sizeof(handshake_hash)); dump_hex("=> digest: %s\n", record.prf_result, sizeof(record.prf_result)); //(1) TODO: well, this should be encrypted on send, really. //(2) do we really need to also hash it? - dbg(">> HANDSHAKE_FINISHED\n"); + dbg(">> FINISHED\n"); xwrite_and_hash(tls, &record, sizeof(record)); } -- cgit v1.2.3