Merge pull request #6078 from yuhaoth/pr/add-tls13-paser-psk-kex-mode-ext

TLS 1.3: PSK: Add parser of psk kex mode ext on server side

include/mbedtls/ssl.h

@@ -169,6 +169,15 @@
 /** Invalid value in SSL config */
 #define MBEDTLS_ERR_SSL_BAD_CONFIG                        -0x5E80
 
+/*
+ * Constants from RFC 8446 for TLS 1.3 PSK modes
+ *
+ * Those are used in the Pre-Shared Key Exchange Modes extension.
+ * See Section 4.2.9 in RFC 8446.
+ */
+#define MBEDTLS_SSL_TLS1_3_PSK_MODE_PURE  0 /* Pure PSK-based exchange  */
+#define MBEDTLS_SSL_TLS1_3_PSK_MODE_ECDHE 1 /* PSK+ECDHE-based exchange */
+
 /*
  * TLS 1.3 NamedGroup values
  *

library/ssl_tls13_server.c

@@ -45,6 +45,60 @@
 #include "ssl_tls13_keys.h"
 #include "ssl_debug_helpers.h"
 
+#if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
+/* From RFC 8446:
+ *
+ *   enum { psk_ke(0), psk_dhe_ke(1), (255) } PskKeyExchangeMode;
+ *   struct {
+ *       PskKeyExchangeMode ke_modes<1..255>;
+ *   } PskKeyExchangeModes;
+ */
+static int ssl_tls13_parse_key_exchange_modes_ext( mbedtls_ssl_context *ssl,
+                                                   const unsigned char *buf,
+                                                   const unsigned char *end )
+{
+    const unsigned char *p = buf;
+    size_t ke_modes_len;
+    int ke_modes = 0;
+
+    /* Read ke_modes length (1 Byte) */
+    MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, 1 );
+    ke_modes_len = *p++;
+    /* Currently, there are only two PSK modes, so even without looking
+     * at the content, something's wrong if the list has more than 2 items. */
+    if( ke_modes_len > 2 )
+    {
+        MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER,
+                                      MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER );
+        return( MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
+    }
+
+    MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, ke_modes_len );
+
+    while( ke_modes_len-- != 0 )
+    {
+        switch( *p++ )
+        {
+        case MBEDTLS_SSL_TLS1_3_PSK_MODE_PURE:
+            ke_modes |= MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK;
+            MBEDTLS_SSL_DEBUG_MSG( 3, ( "Found PSK KEX MODE" ) );
+            break;
+        case MBEDTLS_SSL_TLS1_3_PSK_MODE_ECDHE:
+            ke_modes |= MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL;
+            MBEDTLS_SSL_DEBUG_MSG( 3, ( "Found PSK_EPHEMERAL KEX MODE" ) );
+            break;
+        default:
+            MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER,
+                                          MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER );
+            return( MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER );
+        }
+    }
+
+    ssl->handshake->tls13_kex_modes = ke_modes;
+    return( 0 );
+}
+#endif /* MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED */
+
 /* From RFC 8446:
  *   struct {
  *          ProtocolVersion versions<2..254>;
@@ -754,6 +808,23 @@ static int ssl_tls13_parse_client_hello( mbedtls_ssl_context *ssl,
                 ssl->handshake->extensions_present |= MBEDTLS_SSL_EXT_SUPPORTED_VERSIONS;
                 break;
 
+#if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
+            case MBEDTLS_TLS_EXT_PSK_KEY_EXCHANGE_MODES:
+                MBEDTLS_SSL_DEBUG_MSG( 3, ( "found psk key exchange modes extension" ) );
+
+                ret = ssl_tls13_parse_key_exchange_modes_ext(
+                          ssl, p, extension_data_end );
+                if( ret != 0 )
+                {
+                    MBEDTLS_SSL_DEBUG_RET(
+                        1, "ssl_tls13_parse_key_exchange_modes_ext", ret );
+                    return( ret );
+                }
+
+                ssl->handshake->extensions_present |= MBEDTLS_SSL_EXT_PSK_KEY_EXCHANGE_MODES;
+                break;
+#endif /* MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED */
+
 #if defined(MBEDTLS_SSL_ALPN)
             case MBEDTLS_TLS_EXT_ALPN:
                 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found alpn extension" ) );

tests/ssl-opt.sh

@@ -878,7 +878,9 @@ wait_client_done() {
     CLI_EXIT=$?
 
     kill $DOG_PID >/dev/null 2>&1
-    wait $DOG_PID
+    # For Ubuntu 22.04, `Terminated` message is outputed by wait command.
+    # To remove it from stdout, redirect stdout/stderr to CLI_OUT
+    wait $DOG_PID >> $CLI_OUT 2>&1
 
     echo "EXIT: $CLI_EXIT" >> $CLI_OUT
 
@@ -2229,41 +2231,86 @@ run_test    "SHA-256 allowed by default in client certificate" \
 # ssl_client2/ssl_server2 example programs works.
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3
+requires_config_enabled MBEDTLS_SSL_CLI_C
+requires_config_enabled MBEDTLS_SSL_SRV_C
 run_test    "TLS 1.3: key exchange mode parameter passing: PSK only" \
             "$P_SRV tls13_kex_modes=psk debug_level=4" \
             "$P_CLI tls13_kex_modes=psk debug_level=4" \
             0
+
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3
+requires_config_enabled MBEDTLS_SSL_CLI_C
+requires_config_enabled MBEDTLS_SSL_SRV_C
 run_test    "TLS 1.3: key exchange mode parameter passing: PSK-ephemeral only" \
             "$P_SRV tls13_kex_modes=psk_ephemeral" \
             "$P_CLI tls13_kex_modes=psk_ephemeral" \
             0
+
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3
+requires_config_enabled MBEDTLS_SSL_CLI_C
+requires_config_enabled MBEDTLS_SSL_SRV_C
 run_test    "TLS 1.3: key exchange mode parameter passing: Pure-ephemeral only" \
             "$P_SRV tls13_kex_modes=ephemeral" \
             "$P_CLI tls13_kex_modes=ephemeral" \
             0
+
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3
+requires_config_enabled MBEDTLS_SSL_CLI_C
+requires_config_enabled MBEDTLS_SSL_SRV_C
 run_test    "TLS 1.3: key exchange mode parameter passing: All ephemeral" \
             "$P_SRV tls13_kex_modes=ephemeral_all" \
             "$P_CLI tls13_kex_modes=ephemeral_all" \
             0
+
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3
+requires_config_enabled MBEDTLS_SSL_CLI_C
+requires_config_enabled MBEDTLS_SSL_SRV_C
 run_test    "TLS 1.3: key exchange mode parameter passing: All PSK" \
             "$P_SRV tls13_kex_modes=psk_all" \
             "$P_CLI tls13_kex_modes=psk_all" \
             0
+
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3
+requires_config_enabled MBEDTLS_SSL_CLI_C
+requires_config_enabled MBEDTLS_SSL_SRV_C
 run_test    "TLS 1.3: key exchange mode parameter passing: All" \
             "$P_SRV tls13_kex_modes=all" \
             "$P_CLI tls13_kex_modes=all" \
             0
 
+requires_openssl_tls1_3
+requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
+requires_config_enabled MBEDTLS_SSL_SRV_C
+requires_config_enabled MBEDTLS_DEBUG_C
+run_test    "TLS 1.3: psk_key_exchange_modes: basic check, O->m" \
+            "$P_SRV force_version=tls13 debug_level=5" \
+            "$O_NEXT_CLI -tls1_3 -psk 6162636465666768696a6b6c6d6e6f70 -allow_no_dhe_kex" \
+            0 \
+            -s "found psk key exchange modes extension" \
+            -s "Found PSK_EPHEMERAL KEX MODE" \
+            -s "Found PSK KEX MODE"
+
+requires_gnutls_tls1_3
+requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
+requires_config_enabled MBEDTLS_SSL_SRV_C
+requires_config_enabled MBEDTLS_DEBUG_C
+run_test    "TLS 1.3: psk_key_exchange_modes: basic check, G->m" \
+            "$P_SRV force_version=tls13 debug_level=5" \
+            "$G_NEXT_CLI --priority NORMAL:-VERS-ALL:+VERS-TLS1.3 \
+                         --pskusername Client_identity --pskkey=6162636465666768696a6b6c6d6e6f70 \
+                         localhost" \
+            0 \
+            -s "found psk key exchange modes extension" \
+            -s "Found PSK_EPHEMERAL KEX MODE" \
+            -s "Found PSK KEX MODE"
+
 # Tests for datagram packing
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
 run_test    "DTLS: multiple records in same datagram, client and server" \