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>

1 files 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: