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>

diff --git a/networking/tls.c b/networking/tls.c
index 81820e9a1c1aaf332a9a6055a400522d0c51207c..3df2015a0fc37899d9642f6f469b0e5a088bf163 100644 (file)
--- 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: