From e69d78c0385525a8e77002bebf47c4dcceaee1f4 Mon Sep 17 00:00:00 2001
From: Denys Vlasenko <vda.linux@googlemail.com>
Date: Tue, 17 Jan 2017 17:24:11 +0100
Subject: 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 <vda.linux@googlemail.com>
---
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:
--
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