Merge pull request #8595 from yanrayw/issue/8593/srv-CH-fix-version-check
TLS1.3: SRV: check `min_tls_version` when parsing ClientHello
diff --git a/ChangeLog.d/fix-tls13-server-min-version-check.txt b/ChangeLog.d/fix-tls13-server-min-version-check.txt
new file mode 100644
index 0000000..258ec6d
--- /dev/null
+++ b/ChangeLog.d/fix-tls13-server-min-version-check.txt
@@ -0,0 +1,3 @@
+Bugfix
+ * Fix TLS server accepting TLS 1.2 handshake while TLS 1.2
+ is disabled at runtime. Fixes #8593.
diff --git a/library/ssl_tls13_server.c b/library/ssl_tls13_server.c
index a7c266b..631101e 100644
--- a/library/ssl_tls13_server.c
+++ b/library/ssl_tls13_server.c
@@ -1925,13 +1925,23 @@
* by MBEDTLS_SSL_PROC_CHK_NEG. */
/*
- * Version 1.2 of the protocol has been chosen, set the
+ * Version 1.2 of the protocol has to be used for the handshake.
+ * If TLS 1.2 is not supported, abort the handshake. Otherwise, set the
* ssl->keep_current_message flag for the ClientHello to be kept and parsed
* as a TLS 1.2 ClientHello. We also change ssl->tls_version to
* MBEDTLS_SSL_VERSION_TLS1_2 thus from now on mbedtls_ssl_handshake_step()
* will dispatch to the TLS 1.2 state machine.
*/
if (SSL_CLIENT_HELLO_TLS1_2 == parse_client_hello_ret) {
+ /* Check if server supports TLS 1.2 */
+ if (!mbedtls_ssl_conf_is_tls12_enabled(ssl->conf)) {
+ MBEDTLS_SSL_DEBUG_MSG(
+ 1, ("TLS 1.2 not supported."));
+ MBEDTLS_SSL_PEND_FATAL_ALERT(
+ MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION,
+ MBEDTLS_ERR_SSL_BAD_PROTOCOL_VERSION);
+ return MBEDTLS_ERR_SSL_BAD_PROTOCOL_VERSION;
+ }
ssl->keep_current_message = 1;
ssl->tls_version = MBEDTLS_SSL_VERSION_TLS1_2;
return 0;
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index 92b3e17..2d34f90 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -11756,6 +11756,21 @@
-S "Version: TLS1.2" \
-C "Protocol : TLSv1.2"
+requires_config_enabled MBEDTLS_DEBUG_C
+requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+requires_config_enabled MBEDTLS_SSL_CLI_C
+requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3
+requires_config_enabled MBEDTLS_SSL_SRV_C
+run_test "TLS 1.3 m->m: Not supported version check: cli TLS 1.2 only, srv TLS 1.3 only, fail" \
+ "$P_SRV debug_level=4 max_version=tls13 min_version=tls13" \
+ "$P_CLI debug_level=4 max_version=tls12 min_version=tls12" \
+ 1 \
+ -c "The SSL configuration is tls12 only" \
+ -c "supported_versions(43) extension does not exist." \
+ -c "A fatal alert message was received from our peer" \
+ -s "The SSL configuration is tls13 only" \
+ -s "TLS 1.2 not supported."
+
requires_openssl_tls1_3_with_compatible_ephemeral
requires_config_enabled MBEDTLS_DEBUG_C
requires_config_enabled MBEDTLS_SSL_CLI_C