From e69d78c0385525a8e77002bebf47c4dcceaee1f4 Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Tue, 17 Jan 2017 17:24:11 +0100 Subject: [PATCH] tls: process CHANGE_CIPHER_SPEC and FINISHED from server Successfully finishes handshake with test servers using NULL-SHA256 cipher. The "only" thing remaining before there is a chance this can actually work with real servers is AES encrypt/decrypt. Signed-off-by: Denys Vlasenko --- networking/tls.c | 60 ++++++++++++++++++++++++++---------------------- 1 file changed, 32 insertions(+), 28 deletions(-) diff --git a/networking/tls.c b/networking/tls.c index 81820e9a1..3df2015a0 100644 --- a/networking/tls.c +++ b/networking/tls.c @@ -163,6 +163,7 @@ typedef struct tls_state { uint8_t master_secret[48]; uint8_t encrypt_on_write; + uint8_t decrypt_on_read; uint8_t client_write_MAC_key[SHA256_OUTSIZE]; // RFC 5246 // sequence number @@ -1044,15 +1045,16 @@ static void send_client_key_exchange(tls_state_t *tls) } } +static const uint8_t rec_CHANGE_CIPHER_SPEC[] = { + RECORD_TYPE_CHANGE_CIPHER_SPEC, TLS_MAJ, TLS_MIN, 00, 01, + 01 +}; + static void send_change_cipher_spec(tls_state_t *tls) { - static const uint8_t rec[] = { - RECORD_TYPE_CHANGE_CIPHER_SPEC, TLS_MAJ, TLS_MIN, 00, 01, - 01 - }; /* Not "xwrite_and_hash": this is not a handshake message */ dbg(">> CHANGE_CIPHER_SPEC\n"); - xwrite(tls->fd, rec, sizeof(rec)); + xwrite(tls->fd, rec_CHANGE_CIPHER_SPEC, sizeof(rec_CHANGE_CIPHER_SPEC)); /* tls->write_seq64_be = 0; - already is */ tls->encrypt_on_write = 1; @@ -1138,16 +1140,6 @@ static void send_client_finished(tls_state_t *tls) xwrite_and_hash(tls, &record, sizeof(record)); } -static void get_change_cipher_spec(tls_state_t *tls) -{ - tls->fd = 0; -} - -static void get_server_finished(tls_state_t *tls) -{ - tls->fd = 0; -} - static void tls_handshake(tls_state_t *tls) { // Client RFC 5246 Server @@ -1205,20 +1197,32 @@ static void tls_handshake(tls_state_t *tls) // (i.e. the same format as server certs) // xread_tls_handshake_block(tls, 4); // } - if (tls->inbuf[5] == HANDSHAKE_SERVER_HELLO_DONE) { - // 0e 000000 (len:0) - dbg("got SERVER_HELLO_DONE\n"); - send_client_key_exchange(tls); - send_change_cipher_spec(tls); -//we now should be able to send encrypted... as soon as we grok AES. - send_client_finished(tls); - - get_change_cipher_spec(tls); - get_server_finished(tls); -//we now should receive encrypted, and application data can be sent/received - } else { + if (tls->inbuf[5] != HANDSHAKE_SERVER_HELLO_DONE) tls_error_die(tls); - } + // 0e 000000 (len:0) + dbg("got SERVER_HELLO_DONE\n"); + + send_client_key_exchange(tls); + + send_change_cipher_spec(tls); + /* we now should send encrypted... as soon as we grok AES. */ + + send_client_finished(tls); + + /* Get CHANGE_CIPHER_SPEC */ + len = xread_tls_block(tls); + if (len != 1 || memcmp(tls->inbuf, rec_CHANGE_CIPHER_SPEC, 6) != 0) + tls_error_die(tls); + dbg("got CHANGE_CIPHER_SPEC\n"); + tls->decrypt_on_read = 1; + /* we now should receive encrypted */ + + /* Get (encrypted) FINISHED from the server */ + len = xread_tls_block(tls); + if (len < 4 || tls->inbuf[5] != HANDSHAKE_FINISHED) + tls_error_die(tls); + dbg("got FINISHED\n"); + /* application data can be sent/received */ } // To run a test server using openssl: -- 2.25.1