Don't do version neg on an HRR
authorMatt Caswell <matt@openssl.org>
Fri, 13 Oct 2017 10:41:50 +0000 (11:41 +0100)
committerMatt Caswell <matt@openssl.org>
Mon, 16 Oct 2017 14:52:18 +0000 (15:52 +0100)
Previously if a client received an HRR then we would do version negotiation
immediately - because we know we are going to get TLSv1.3. However this
causes a problem when we emit the 2nd ClientHello because we start changing
a whole load of stuff to ommit things that aren't relevant for < TLSv1.3.
The spec requires that the 2nd ClientHello is the same except for changes
required from the HRR. Therefore the simplest thing to do is to defer the
version negotiation until we receive the ServerHello.

Fixes #4292

Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Ben Kaduk <kaduk@mit.edu>
(Merged from https://github.com/openssl/openssl/pull/4527)

ssl/record/ssl3_record.c
ssl/statem/extensions.c
ssl/statem/statem_clnt.c
test/recipes/70-test_tls13kexmodes.t
test/recipes/70-test_tls13messages.t

index ee02622..e17b2f0 100644 (file)
@@ -271,8 +271,13 @@ int ssl3_get_record(SSL *s)
                 thisrr->type = type;
                 thisrr->rec_version = version;
 
-                /* Lets check version. In TLSv1.3 we ignore this field */
+                /*
+                 * Lets check version. In TLSv1.3 we ignore this field. For an
+                 * HRR we haven't actually selected TLSv1.3 yet, but we still
+                 * treat it as TLSv1.3, so we must check for that explicitly
+                 */
                 if (!s->first_packet && !SSL_IS_TLS13(s)
+                        && !s->hello_retry_request
                         && version != (unsigned int)s->version) {
                     SSLerr(SSL_F_SSL3_GET_RECORD, SSL_R_WRONG_VERSION_NUMBER);
                     if ((s->version & 0xFF00) == (version & 0xFF00)
index b5091ac..e16b75f 100644 (file)
@@ -408,13 +408,23 @@ static int verify_extension(SSL *s, unsigned int context, unsigned int type,
  */
 int extension_is_relevant(SSL *s, unsigned int extctx, unsigned int thisctx)
 {
+    int is_tls13;
+
+    /*
+     * For HRR we haven't selected the version yet but we know it will be
+     * TLSv1.3
+     */
+    if ((thisctx & SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST) != 0)
+        is_tls13 = 1;
+    else
+        is_tls13 = SSL_IS_TLS13(s);
+
     if ((SSL_IS_DTLS(s)
                 && (extctx & SSL_EXT_TLS_IMPLEMENTATION_ONLY) != 0)
             || (s->version == SSL3_VERSION
                     && (extctx & SSL_EXT_SSL3_ALLOWED) == 0)
-            || (SSL_IS_TLS13(s)
-                && (extctx & SSL_EXT_TLS1_2_AND_BELOW_ONLY) != 0)
-            || (!SSL_IS_TLS13(s) && (extctx & SSL_EXT_TLS1_3_ONLY) != 0)
+            || (is_tls13 && (extctx & SSL_EXT_TLS1_2_AND_BELOW_ONLY) != 0)
+            || (!is_tls13 && (extctx & SSL_EXT_TLS1_3_ONLY) != 0)
             || (s->hit && (extctx & SSL_EXT_IGNORE_ON_RESUMPTION) != 0))
         return 0;
 
index 88c0889..fdf5d45 100644 (file)
@@ -391,10 +391,6 @@ static WRITE_TRAN ossl_statem_client13_write_transition(SSL *s)
         /* We only hit this in the case of HelloRetryRequest */
         return WRITE_TRAN_FINISHED;
 
-    case TLS_ST_CR_HELLO_RETRY_REQUEST:
-        st->hand_state = TLS_ST_CW_CLNT_HELLO;
-        return WRITE_TRAN_CONTINUE;
-
     case TLS_ST_CR_FINISHED:
         if (s->early_data_state == SSL_EARLY_DATA_WRITE_RETRY
                 || s->early_data_state == SSL_EARLY_DATA_FINISHED_WRITING)
@@ -500,6 +496,10 @@ WRITE_TRAN ossl_statem_client_write_transition(SSL *s)
          */
         return WRITE_TRAN_FINISHED;
 
+    case TLS_ST_CR_HELLO_RETRY_REQUEST:
+        st->hand_state = TLS_ST_CW_CLNT_HELLO;
+        return WRITE_TRAN_CONTINUE;
+
     case TLS_ST_EARLY_DATA:
         return WRITE_TRAN_FINISHED;
 
@@ -1558,7 +1558,6 @@ MSG_PROCESS_RETURN tls_process_server_hello(SSL *s, PACKET *pkt)
 static MSG_PROCESS_RETURN tls_process_hello_retry_request(SSL *s, PACKET *pkt)
 {
     unsigned int sversion;
-    int errorcode;
     const unsigned char *cipherchars;
     RAW_EXTENSION *extensions = NULL;
     int al;
@@ -1579,13 +1578,6 @@ static MSG_PROCESS_RETURN tls_process_hello_retry_request(SSL *s, PACKET *pkt)
     EVP_CIPHER_CTX_free(s->enc_write_ctx);
     s->enc_write_ctx = NULL;
 
-    /* This will fail if it doesn't choose TLSv1.3+ */
-    errorcode = ssl_choose_client_version(s, sversion, 0, &al);
-    if (errorcode != 0) {
-        SSLerr(SSL_F_TLS_PROCESS_HELLO_RETRY_REQUEST, errorcode);
-        goto f_err;
-    }
-
     if (!PACKET_get_bytes(pkt, &cipherchars, TLS_CIPHER_LEN)) {
         SSLerr(SSL_F_TLS_PROCESS_HELLO_RETRY_REQUEST, SSL_R_LENGTH_MISMATCH);
         al = SSL_AD_DECODE_ERROR;
index fe7415a..3f3cfaf 100644 (file)
@@ -99,12 +99,20 @@ $ENV{CTLOG_FILE} = srctop_file("test", "ct", "log_list.conf");
         checkhandshake::STATUS_REQUEST_CLI_EXTENSION],
     [TLSProxy::Message::MT_CLIENT_HELLO, TLSProxy::Message::EXT_SUPPORTED_GROUPS,
         checkhandshake::DEFAULT_EXTENSIONS],
+    [TLSProxy::Message::MT_CLIENT_HELLO, TLSProxy::Message::EXT_EC_POINT_FORMATS,
+        checkhandshake::DEFAULT_EXTENSIONS],
     [TLSProxy::Message::MT_CLIENT_HELLO, TLSProxy::Message::EXT_SIG_ALGS,
         checkhandshake::DEFAULT_EXTENSIONS],
     [TLSProxy::Message::MT_CLIENT_HELLO, TLSProxy::Message::EXT_ALPN,
         checkhandshake::ALPN_CLI_EXTENSION],
     [TLSProxy::Message::MT_CLIENT_HELLO, TLSProxy::Message::EXT_SCT,
         checkhandshake::SCT_CLI_EXTENSION],
+    [TLSProxy::Message::MT_CLIENT_HELLO, TLSProxy::Message::EXT_ENCRYPT_THEN_MAC,
+        checkhandshake::DEFAULT_EXTENSIONS],
+    [TLSProxy::Message::MT_CLIENT_HELLO, TLSProxy::Message::EXT_EXTENDED_MASTER_SECRET,
+        checkhandshake::DEFAULT_EXTENSIONS],
+    [TLSProxy::Message::MT_CLIENT_HELLO, TLSProxy::Message::EXT_SESSION_TICKET,
+        checkhandshake::DEFAULT_EXTENSIONS],
     [TLSProxy::Message::MT_CLIENT_HELLO, TLSProxy::Message::EXT_KEY_SHARE,
         checkhandshake::DEFAULT_EXTENSIONS],
     [TLSProxy::Message::MT_CLIENT_HELLO, TLSProxy::Message::EXT_SUPPORTED_VERSIONS,
index 24ffb80..239eabf 100644 (file)
@@ -99,12 +99,20 @@ $ENV{CTLOG_FILE} = srctop_file("test", "ct", "log_list.conf");
         checkhandshake::STATUS_REQUEST_CLI_EXTENSION],
     [TLSProxy::Message::MT_CLIENT_HELLO, TLSProxy::Message::EXT_SUPPORTED_GROUPS,
         checkhandshake::DEFAULT_EXTENSIONS],
+    [TLSProxy::Message::MT_CLIENT_HELLO, TLSProxy::Message::EXT_EC_POINT_FORMATS,
+        checkhandshake::DEFAULT_EXTENSIONS],
     [TLSProxy::Message::MT_CLIENT_HELLO, TLSProxy::Message::EXT_SIG_ALGS,
         checkhandshake::DEFAULT_EXTENSIONS],
     [TLSProxy::Message::MT_CLIENT_HELLO, TLSProxy::Message::EXT_ALPN,
         checkhandshake::ALPN_CLI_EXTENSION],
     [TLSProxy::Message::MT_CLIENT_HELLO, TLSProxy::Message::EXT_SCT,
         checkhandshake::SCT_CLI_EXTENSION],
+    [TLSProxy::Message::MT_CLIENT_HELLO, TLSProxy::Message::EXT_ENCRYPT_THEN_MAC,
+        checkhandshake::DEFAULT_EXTENSIONS],
+    [TLSProxy::Message::MT_CLIENT_HELLO, TLSProxy::Message::EXT_EXTENDED_MASTER_SECRET,
+        checkhandshake::DEFAULT_EXTENSIONS],
+    [TLSProxy::Message::MT_CLIENT_HELLO, TLSProxy::Message::EXT_SESSION_TICKET,
+        checkhandshake::DEFAULT_EXTENSIONS],
     [TLSProxy::Message::MT_CLIENT_HELLO, TLSProxy::Message::EXT_KEY_SHARE,
         checkhandshake::DEFAULT_EXTENSIONS],
     [TLSProxy::Message::MT_CLIENT_HELLO, TLSProxy::Message::EXT_SUPPORTED_VERSIONS,