}
#endif
+/*
+ * Comparison function used in a call to qsort (see tls_collect_extensions()
+ * below.)
+ * The two arguments |p1| and |p2| are expected to be pointers to RAW_EXTENSIONs
+ *
+ * Returns:
+ * 1 if the type for p1 is greater than p2
+ * 0 if the type for p1 and p2 are the same
+ * -1 if the type for p1 is less than p2
+ */
+static int compare_extensions(const void *p1, const void *p2)
+{
+ const RAW_EXTENSION *e1 = (const RAW_EXTENSION *)p1;
+ const RAW_EXTENSION *e2 = (const RAW_EXTENSION *)p2;
+
+ if (e1->type < e2->type)
+ return -1;
+ else if (e1->type > e2->type)
+ return 1;
+
+ return 0;
+}
+
+/*
+ * Gather a list of all the extensions. We don't actually process the content
+ * of the extensions yet, except to check their types.
+ *
+ * Per http://tools.ietf.org/html/rfc5246#section-7.4.1.4, there may not be
+ * more than one extension of the same type in a ClientHello or ServerHello.
+ * This function returns 1 if all extensions are unique and we have parsed their
+ * types, and 0 if the extensions contain duplicates, could not be successfully
+ * parsed, or an internal error occurred.
+ */
+/*
+ * TODO(TLS1.3): Refactor ServerHello extension parsing to use this and then
+ * remove tls1_check_duplicate_extensions()
+ */
+int tls_collect_extensions(PACKET *packet, RAW_EXTENSION **res,
+ size_t *numfound, int *ad)
+{
+ PACKET extensions = *packet;
+ size_t num_extensions = 0, i = 0;
+ RAW_EXTENSION *raw_extensions = NULL;
+
+ /* First pass: count the extensions. */
+ while (PACKET_remaining(&extensions) > 0) {
+ unsigned int type;
+ PACKET extension;
+
+ if (!PACKET_get_net_2(&extensions, &type) ||
+ !PACKET_get_length_prefixed_2(&extensions, &extension)) {
+ *ad = SSL_AD_DECODE_ERROR;
+ goto err;
+ }
+ num_extensions++;
+ }
+
+ if (num_extensions > 0) {
+ raw_extensions = OPENSSL_malloc(sizeof(*raw_extensions)
+ * num_extensions);
+ if (raw_extensions == NULL) {
+ *ad = SSL_AD_INTERNAL_ERROR;
+ SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, ERR_R_MALLOC_FAILURE);
+ goto err;
+ }
+
+ /* Second pass: collect the extensions. */
+ for (i = 0; i < num_extensions; i++) {
+ if (!PACKET_get_net_2(packet, &raw_extensions[i].type) ||
+ !PACKET_get_length_prefixed_2(packet,
+ &raw_extensions[i].data)) {
+ /* This should not happen. */
+ *ad = SSL_AD_INTERNAL_ERROR;
+ SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, ERR_R_INTERNAL_ERROR);
+ goto err;
+ }
+ }
+
+ if (PACKET_remaining(packet) != 0) {
+ *ad = SSL_AD_DECODE_ERROR;
+ SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, SSL_R_LENGTH_MISMATCH);
+ goto err;
+ }
+ /* Sort the extensions and make sure there are no duplicates. */
+ qsort(raw_extensions, num_extensions, sizeof(*raw_extensions),
+ compare_extensions);
+ for (i = 1; i < num_extensions; i++) {
+ if (raw_extensions[i - 1].type == raw_extensions[i].type) {
+ *ad = SSL_AD_DECODE_ERROR;
+ goto err;
+ }
+ }
+ }
+
+ *res = raw_extensions;
+ *numfound = num_extensions;
+ return 1;
+
+ err:
+ OPENSSL_free(raw_extensions);
+ return 0;
+}
+
+
+
MSG_PROCESS_RETURN tls_process_change_cipher_spec(SSL *s, PACKET *pkt)
{
int al;
*
* Returns 0 on success or an SSL error reason number on failure.
*/
-int ssl_choose_server_version(SSL *s)
+int ssl_choose_server_version(SSL *s, CLIENTHELLO_MSG *hello)
{
/*-
* With version-flexible methods we have an initial state with:
* handle version.
*/
int server_version = s->method->version;
- int client_version = s->client_version;
+ int client_version = hello->legacy_version;
const version_info *vent;
const version_info *table;
int disabled = 0;
+ RAW_EXTENSION *suppversions;
+
+ s->client_version = client_version;
switch (server_version) {
default:
break;
}
+ suppversions = tls_get_extension_by_type(hello->pre_proc_exts,
+ hello->num_extensions,
+ TLSEXT_TYPE_supported_versions);
+
+ /*
+ * TODO(TLS1.3): We only look at this if our max protocol version is TLS1.3
+ * or above. Should we allow it for lower versions too?
+ */
+ if (suppversions != NULL && !SSL_IS_DTLS(s)
+ && (s->max_proto_version == 0
+ || TLS1_3_VERSION <= s->max_proto_version)) {
+ unsigned int candidate_vers = 0;
+ unsigned int best_vers = 0;
+ const SSL_METHOD *best_method = NULL;
+ PACKET versionslist;
+
+ if (!PACKET_as_length_prefixed_1(&suppversions->data, &versionslist)) {
+ /* Trailing or invalid data? */
+ return SSL_R_LENGTH_MISMATCH;
+ }
+
+ while (PACKET_get_net_2(&versionslist, &candidate_vers)) {
+ /* TODO(TLS1.3): Remove this before release */
+ if (candidate_vers == TLS1_3_VERSION_DRAFT)
+ candidate_vers = TLS1_3_VERSION;
+ if ((int)candidate_vers > s->client_version)
+ s->client_version = candidate_vers;
+ if (version_cmp(s, candidate_vers, best_vers) <= 0)
+ continue;
+ for (vent = table;
+ vent->version != 0 && vent->version != (int)candidate_vers;
+ ++vent)
+ ;
+ if (vent->version != 0) {
+ const SSL_METHOD *method;
+
+ method = vent->smeth();
+ if (ssl_method_error(s, method) == 0) {
+ best_vers = candidate_vers;
+ best_method = method;
+ }
+ }
+ }
+ if (PACKET_remaining(&versionslist) != 0) {
+ /* Trailing data? */
+ return SSL_R_LENGTH_MISMATCH;
+ }
+
+ if (best_vers > 0) {
+ s->version = best_vers;
+ s->method = best_method;
+ return 0;
+ }
+ return SSL_R_UNSUPPORTED_PROTOCOL;
+ }
+
+ /*
+ * If the supported versions extension isn't present, then the highest
+ * version we can negotiate is TLSv1.2
+ */
+ if (version_cmp(s, client_version, TLS1_3_VERSION) >= 0)
+ client_version = TLS1_2_VERSION;
+
+ /*
+ * No supported versions extension, so we just use the version supplied in
+ * the ClientHello.
+ */
for (vent = table; vent->version != 0; ++vent) {
const SSL_METHOD *method;
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