Merge branch 'bugfix/mbedtls_disable_dhe_by_default' into 'master'

mbedtls: disable Diffie-Hellman key exchange modes by default

Closes IDF-1230

See merge request espressif/esp-idf!15642

components/esp-tls/Kconfig

@@ -66,8 +66,8 @@ menu "ESP-TLS"
         bool "Enable PSK verification"
         select MBEDTLS_PSK_MODES if ESP_TLS_USING_MBEDTLS
         select MBEDTLS_KEY_EXCHANGE_PSK if ESP_TLS_USING_MBEDTLS
-        select MBEDTLS_KEY_EXCHANGE_DHE_PSK if ESP_TLS_USING_MBEDTLS
-        select MBEDTLS_KEY_EXCHANGE_ECDHE_PSK if ESP_TLS_USING_MBEDTLS
+        select MBEDTLS_KEY_EXCHANGE_DHE_PSK if ESP_TLS_USING_MBEDTLS && MBEDTLS_DHM_C
+        select MBEDTLS_KEY_EXCHANGE_ECDHE_PSK if ESP_TLS_USING_MBEDTLS && MBEDTLS_ECDH_C
         select MBEDTLS_KEY_EXCHANGE_RSA_PSK if ESP_TLS_USING_MBEDTLS
         default n
         help

components/mbedtls/Kconfig

@@ -426,7 +426,7 @@ menu "mbedTLS"
 
         config MBEDTLS_KEY_EXCHANGE_DHE_PSK
             bool "Enable DHE-PSK based ciphersuite modes"
-            depends on MBEDTLS_PSK_MODES
+            depends on MBEDTLS_PSK_MODES && MBEDTLS_DHM_C
             default y
             help
                 Enable to support Diffie-Hellman PSK (pre-shared-key) TLS authentication modes.
@@ -454,6 +454,7 @@ menu "mbedTLS"
         config MBEDTLS_KEY_EXCHANGE_DHE_RSA
             bool "Enable DHE-RSA based ciphersuite modes"
             default y
+            depends on MBEDTLS_DHM_C
             help
                 Enable to support ciphersuites with prefix TLS-DHE-RSA-WITH-
 
@@ -716,6 +717,16 @@ menu "mbedTLS"
         bool  "Elliptic Curve Ciphers"
         default y
 
+    config MBEDTLS_DHM_C
+        bool "Diffie-Hellman-Merkle key exchange (DHM)"
+        default n
+        help
+            Enable DHM. Needed to use DHE-xxx TLS ciphersuites.
+
+            Note that the security of Diffie-Hellman key exchanges depends on
+            a suitable prime being used for the exchange. Please see detailed
+            warning text about this in file `mbedtls/dhm.h` file.
+
     config MBEDTLS_ECDH_C
         bool "Elliptic Curve Diffie-Hellman (ECDH)"
         depends on MBEDTLS_ECP_C

components/mbedtls/port/dynamic/esp_mbedtls_dynamic_impl.c

@@ -1,16 +1,8 @@
-// Copyright 2020 Espressif Systems (Shanghai) PTE LTD
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
+/*
+ * SPDX-FileCopyrightText: 2020-2021 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
 
 #include <string.h>
 #include "esp_mbedtls_dynamic_impl.h"
@@ -471,8 +463,10 @@ size_t esp_mbedtls_get_crt_size(mbedtls_x509_crt *cert, size_t *num)
 #ifdef CONFIG_MBEDTLS_DYNAMIC_FREE_CONFIG_DATA
 void esp_mbedtls_free_dhm(mbedtls_ssl_context *ssl)
 {
+#ifdef CONFIG_MBEDTLS_DHM_C
     mbedtls_mpi_free((mbedtls_mpi *)&ssl->conf->dhm_P);
     mbedtls_mpi_free((mbedtls_mpi *)&ssl->conf->dhm_G);
+#endif /* CONFIG_MBEDTLS_DHM_C */
 }
 
 void esp_mbedtls_free_keycert(mbedtls_ssl_context *ssl)

components/mbedtls/port/include/mbedtls/esp_config.h

@@ -1601,7 +1601,11 @@
  * This module is used by the following key exchanges:
  *      DHE-RSA, DHE-PSK
  */
+#ifdef CONFIG_MBEDTLS_DHM_C
 #define MBEDTLS_DHM_C
+#else
+#undef MBEDTLS_DHM_C
+#endif
 
 /**
  * \def MBEDTLS_ECDH_C

examples/bluetooth/blufi/sdkconfig.defaults

@@ -37,3 +37,4 @@ CONFIG_BT_BLE_DYNAMIC_ENV_MEMORY=n
 CONFIG_BT_SMP_ENABLE=n
 CONFIG_BT_BLE_BLUFI_ENABLE=y
 CONFIG_MBEDTLS_HARDWARE_MPI=n
+CONFIG_MBEDTLS_DHM_C=y

tools/ci/check_copyright_ignore.txt

@@ -1555,7 +1555,6 @@ components/mbedtls/port/aes/esp_aes_common.c
 components/mbedtls/port/aes/esp_aes_gcm.c
 components/mbedtls/port/aes/esp_aes_xts.c
 components/mbedtls/port/crypto_shared_gdma/esp_crypto_shared_gdma.c
-components/mbedtls/port/dynamic/esp_mbedtls_dynamic_impl.c
 components/mbedtls/port/dynamic/esp_mbedtls_dynamic_impl.h
 components/mbedtls/port/dynamic/esp_ssl_cli.c
 components/mbedtls/port/dynamic/esp_ssl_srv.c