Remove MBEDTLS_SSL_EXPORT_KEYS, making it always on

This option only gated an ability to set a callback,
but was deemed unnecessary as it was yet another define to
remember when writing tests, or test configurations. Fixes #4653.
Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>

ChangeLog.d/remove-ssl-export-keys.txt

@@ -0,0 +1,5 @@
+Changes
+   * Remove MBEDTLS_SSL_EXPORT_KEYS, making it always on and increasing the
+     code size by about 80B on an M0 build. This option only gated an ability
+     to set a callback, but was deemed unnecessary as it was yet another define
+     to remember when writing tests, or test configurations. Fixes #4653.

configs/config-thread.h

@@ -45,7 +45,6 @@
 #define MBEDTLS_SSL_PROTO_DTLS
 #define MBEDTLS_SSL_DTLS_ANTI_REPLAY
 #define MBEDTLS_SSL_DTLS_HELLO_VERIFY
-#define MBEDTLS_SSL_EXPORT_KEYS
 
 /* mbed TLS modules */
 #define MBEDTLS_AES_C

include/mbedtls/mbedtls_config.h

@@ -1598,16 +1598,6 @@
  */
 #define MBEDTLS_SSL_SESSION_TICKETS
 
-/**
- * \def MBEDTLS_SSL_EXPORT_KEYS
- *
- * Enable support for exporting key block and master secret.
- * This is required for certain users of TLS, e.g. EAP-TLS.
- *
- * Comment this macro to disable support for key export
- */
-#define MBEDTLS_SSL_EXPORT_KEYS
-
 /**
  * \def MBEDTLS_SSL_SERVER_NAME_INDICATION
  *

include/mbedtls/ssl.h

@@ -1139,7 +1139,6 @@ typedef enum
 }
 mbedtls_tls_prf_types;
 
-#if defined(MBEDTLS_SSL_EXPORT_KEYS)
 typedef enum
 {
     MBEDTLS_SSL_KEY_EXPORT_TLS12_MASTER_SECRET = 0,
@@ -1175,7 +1174,6 @@ typedef void mbedtls_ssl_export_keys_t( void *p_expkey,
                                         const unsigned char client_random[32],
                                         const unsigned char server_random[32],
                                         mbedtls_tls_prf_types tls_prf_type );
-#endif /* MBEDTLS_SSL_EXPORT_KEYS */
 
 /**
  * SSL/TLS configuration to be shared between mbedtls_ssl_context structures.
@@ -1617,11 +1615,9 @@ struct mbedtls_ssl_context
                             *   and #MBEDTLS_SSL_CID_DISABLED. */
 #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
 
-#if defined(MBEDTLS_SSL_EXPORT_KEYS)
     /** Callback to export key block and master secret                      */
     mbedtls_ssl_export_keys_t *MBEDTLS_PRIVATE(f_export_keys);
     void *MBEDTLS_PRIVATE(p_export_keys);            /*!< context for key export callback    */
-#endif
 };
 
 /**
@@ -2194,7 +2190,6 @@ void mbedtls_ssl_conf_session_tickets_cb( mbedtls_ssl_config *conf,
         void *p_ticket );
 #endif /* MBEDTLS_SSL_SESSION_TICKETS && MBEDTLS_SSL_SRV_C */
 
-#if defined(MBEDTLS_SSL_EXPORT_KEYS)
 /**
  * \brief   Configure a key export callback.
  *          (Default: none.)
@@ -2216,7 +2211,6 @@ void mbedtls_ssl_conf_session_tickets_cb( mbedtls_ssl_config *conf,
 void mbedtls_ssl_set_export_keys_cb( mbedtls_ssl_context *ssl,
                                      mbedtls_ssl_export_keys_t *f_export_keys,
                                      void *p_export_keys );
-#endif /* MBEDTLS_SSL_EXPORT_KEYS */
 
 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
 /**

library/ssl_tls.c

@@ -587,7 +587,6 @@ static int ssl_use_opaque_psk( mbedtls_ssl_context const *ssl )
 #endif /* MBEDTLS_USE_PSA_CRYPTO &&
           MBEDTLS_KEY_EXCHANGE_PSK_ENABLED */
 
-#if defined(MBEDTLS_SSL_EXPORT_KEYS)
 static mbedtls_tls_prf_types tls_prf_get_type( mbedtls_ssl_tls_prf_cb *tls_prf )
 {
 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
@@ -608,7 +607,6 @@ static mbedtls_tls_prf_types tls_prf_get_type( mbedtls_ssl_tls_prf_cb *tls_prf )
 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
     return( MBEDTLS_SSL_TLS_PRF_NONE );
 }
-#endif /* MBEDTLS_SSL_EXPORT_KEYS */
 
 int  mbedtls_ssl_tls_prf( const mbedtls_tls_prf_types prf,
                           const unsigned char *secret, size_t slen,
@@ -660,8 +658,9 @@ typedef int ssl_tls_prf_t(const unsigned char *, size_t, const char *,
  * - [in] randbytes: buffer holding ServerHello.random + ClientHello.random
  * - [in] minor_ver: SSL/TLS minor version
  * - [in] endpoint: client or server
- * - [in] ssl: optionally used for:
+ * - [in] ssl: used for:
- *        - MBEDTLS_SSL_EXPORT_KEYS: ssl->conf->{f,p}_export_keys
+ *        - ssl->conf->{f,p}_export_keys
+ *      [in] optionally used for:
  *        - MBEDTLS_DEBUG_C: ssl->conf->{f,p}_dbg
  */
 static int ssl_tls12_populate_transform( mbedtls_ssl_transform *transform,
@@ -694,9 +693,8 @@ static int ssl_tls12_populate_transform( mbedtls_ssl_transform *transform,
     const mbedtls_cipher_info_t *cipher_info;
     const mbedtls_md_info_t *md_info;
 
-#if !defined(MBEDTLS_SSL_EXPORT_KEYS) && \
+#if !defined(MBEDTLS_DEBUG_C)
-    !defined(MBEDTLS_DEBUG_C)
+    ssl = NULL; /* make sure we don't use it except for this case */
-    ssl = NULL; /* make sure we don't use it except for those cases */
     (void) ssl;
 #endif
 
@@ -960,7 +958,6 @@ static int ssl_tls12_populate_transform( mbedtls_ssl_transform *transform,
     ((void) mac_dec);
     ((void) mac_enc);
 
-#if defined(MBEDTLS_SSL_EXPORT_KEYS)
     if( ssl->f_export_keys != NULL )
     {
         ssl->f_export_keys( ssl->p_export_keys,
@@ -970,7 +967,6 @@ static int ssl_tls12_populate_transform( mbedtls_ssl_transform *transform,
                             randbytes,
                             tls_prf_get_type( tls_prf ) );
     }
-#endif
 
 #if defined(MBEDTLS_USE_PSA_CRYPTO)
 
@@ -4229,7 +4225,6 @@ void mbedtls_ssl_conf_session_tickets_cb( mbedtls_ssl_config *conf,
 #endif
 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
 
-#if defined(MBEDTLS_SSL_EXPORT_KEYS)
 void mbedtls_ssl_set_export_keys_cb( mbedtls_ssl_context *ssl,
                                      mbedtls_ssl_export_keys_t *f_export_keys,
                                      void *p_export_keys )
@@ -4237,7 +4232,6 @@ void mbedtls_ssl_set_export_keys_cb( mbedtls_ssl_context *ssl,
     ssl->f_export_keys = f_export_keys;
     ssl->p_export_keys = p_export_keys;
 }
-#endif
 
 #if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
 void mbedtls_ssl_conf_async_private_cb(

programs/ssl/ssl_client2.c

@@ -207,7 +207,6 @@ int main( void )
 #define USAGE_TICKETS ""
 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
 
-#if defined(MBEDTLS_SSL_EXPORT_KEYS)
 #define USAGE_EAP_TLS                                       \
     "    eap_tls=%%d          default: 0 (disabled)\n"
 #define USAGE_NSS_KEYLOG                                    \
@@ -230,12 +229,6 @@ int main( void )
 #else /* MBEDTLS_SSL_DTLS_SRTP */
 #define USAGE_SRTP ""
 #endif
-#else /* MBEDTLS_SSL_EXPORT_KEYS */
-#define USAGE_EAP_TLS ""
-#define USAGE_NSS_KEYLOG ""
-#define USAGE_NSS_KEYLOG_FILE ""
-#define USAGE_SRTP ""
-#endif /* MBEDTLS_SSL_EXPORT_KEYS */
 
 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
 #define USAGE_MAX_FRAG_LEN                                      \
@@ -729,7 +722,6 @@ int main( int argc, char *argv[] )
     unsigned char *context_buf = NULL;
     size_t context_buf_len;
 #endif
-#if defined(MBEDTLS_SSL_EXPORT_KEYS)
     unsigned char eap_tls_keymaterial[16];
     unsigned char eap_tls_iv[8];
     const char* eap_tls_label = "client EAP encryption";
@@ -747,7 +739,6 @@ int main( int argc, char *argv[] )
         MBEDTLS_TLS_SRTP_UNSET
     };
 #endif /* MBEDTLS_SSL_DTLS_SRTP */
-#endif /* MBEDTLS_SSL_EXPORT_KEYS */
 
 #if defined(MBEDTLS_MEMORY_BUFFER_ALLOC_C)
     mbedtls_memory_buffer_alloc_init( alloc_buf, sizeof(alloc_buf) );
@@ -1962,7 +1953,6 @@ int main( int argc, char *argv[] )
         goto exit;
     }
 
-#if defined(MBEDTLS_SSL_EXPORT_KEYS)
     if( opt.eap_tls != 0 )
     {
         mbedtls_ssl_set_export_keys_cb( &ssl, eap_tls_key_derivation,
@@ -1981,7 +1971,6 @@ int main( int argc, char *argv[] )
                                         &dtls_srtp_keying );
     }
 #endif /* MBEDTLS_SSL_DTLS_SRTP */
-#endif /* MBEDTLS_SSL_EXPORT_KEYS */
 
 #if defined(MBEDTLS_X509_CRT_PARSE_C)
     if( ( ret = mbedtls_ssl_set_hostname( &ssl, opt.server_name ) ) != 0 )
@@ -2169,7 +2158,6 @@ int main( int argc, char *argv[] )
     }
 #endif
 
-#if defined(MBEDTLS_SSL_EXPORT_KEYS)
     if( opt.eap_tls != 0  )
     {
         size_t j = 0;
@@ -2286,7 +2274,6 @@ int main( int argc, char *argv[] )
         }
     }
 #endif /* MBEDTLS_SSL_DTLS_SRTP */
-#endif /* MBEDTLS_SSL_EXPORT_KEYS */
     if( opt.reconnect != 0 )
     {
         mbedtls_printf("  . Saving session for reuse..." );

programs/ssl/ssl_server2.c

@@ -278,7 +278,6 @@ int main( void )
 #define USAGE_TICKETS ""
 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
 
-#if defined(MBEDTLS_SSL_EXPORT_KEYS)
 #define USAGE_EAP_TLS                                       \
     "    eap_tls=%%d          default: 0 (disabled)\n"
 #define USAGE_NSS_KEYLOG                                    \
@@ -299,12 +298,6 @@ int main( void )
 #else /* MBEDTLS_SSL_DTLS_SRTP */
 #define USAGE_SRTP ""
 #endif
-#else /* MBEDTLS_SSL_EXPORT_KEYS */
-#define USAGE_EAP_TLS ""
-#define USAGE_NSS_KEYLOG ""
-#define USAGE_NSS_KEYLOG_FILE ""
-#define USAGE_SRTP ""
-#endif /* MBEDTLS_SSL_EXPORT_KEYS */
 
 #if defined(MBEDTLS_SSL_CACHE_C)
 #define USAGE_CACHE                                             \
@@ -1365,7 +1358,6 @@ int main( int argc, char *argv[] )
 #if defined(MBEDTLS_USE_PSA_CRYPTO)
     psa_status_t status;
 #endif
-#if defined(MBEDTLS_SSL_EXPORT_KEYS)
     unsigned char eap_tls_keymaterial[16];
     unsigned char eap_tls_iv[8];
     const char* eap_tls_label = "client EAP encryption";
@@ -1383,7 +1375,6 @@ int main( int argc, char *argv[] )
          MBEDTLS_TLS_SRTP_UNSET
      };
 #endif /* MBEDTLS_SSL_DTLS_SRTP */
-#endif /* MBEDTLS_SSL_EXPORT_KEYS */
 
 #if defined(MBEDTLS_MEMORY_BUFFER_ALLOC_C)
     mbedtls_memory_buffer_alloc_init( alloc_buf, sizeof(alloc_buf) );
@@ -2966,7 +2957,6 @@ int main( int argc, char *argv[] )
         goto exit;
     }
 
-#if defined(MBEDTLS_SSL_EXPORT_KEYS)
     if( opt.eap_tls != 0 )
     {
         mbedtls_ssl_set_export_keys_cb( &ssl, eap_tls_key_derivation,
@@ -2985,7 +2975,6 @@ int main( int argc, char *argv[] )
                                         &dtls_srtp_keying );
     }
 #endif /* MBEDTLS_SSL_DTLS_SRTP */
-#endif /* MBEDTLS_SSL_EXPORT_KEYS */
 
     io_ctx.ssl = &ssl;
     io_ctx.net = &client_fd;
@@ -3251,7 +3240,6 @@ handshake:
 #endif /* MBEDTLS_X509_REMOVE_INFO */
 #endif /* MBEDTLS_X509_CRT_PARSE_C */
 
-#if defined(MBEDTLS_SSL_EXPORT_KEYS)
     if( opt.eap_tls != 0 )
     {
         size_t j = 0;
@@ -3369,7 +3357,6 @@ handshake:
         }
     }
 #endif /* MBEDTLS_SSL_DTLS_SRTP */
-#endif /* MBEDTLS_SSL_EXPORT_KEYS */
 
 #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
     ret = report_cid_usage( &ssl, "initial handshake" );

programs/ssl/ssl_test_common_source.c

@@ -24,7 +24,6 @@
  *  limitations under the License.
  */
 
-#if defined(MBEDTLS_SSL_EXPORT_KEYS)
 void eap_tls_key_derivation( void *p_expkey,
                              mbedtls_ssl_key_export_type secret_type,
                              const unsigned char *secret,
@@ -140,8 +139,6 @@ void dtls_srtp_key_derivation( void *p_expkey,
 }
 #endif /* MBEDTLS_SSL_DTLS_SRTP */
 
-#endif /* MBEDTLS_SSL_EXPORT_KEYS */
-
 int ssl_check_record( mbedtls_ssl_context const *ssl,
                       unsigned char const *buf, size_t len )
 {

programs/ssl/ssl_test_lib.h

@@ -95,8 +95,6 @@
 
 #include "../test/query_config.h"
 
-#if defined(MBEDTLS_SSL_EXPORT_KEYS)
-
 typedef struct eap_tls_keys
 {
     unsigned char master_secret[48];
@@ -122,8 +120,6 @@ typedef struct dtls_srtp_keys
 
 #endif /* MBEDTLS_SSL_DTLS_SRTP */
 
-#endif /* MBEDTLS_SSL_EXPORT_KEYS */
-
 typedef struct
 {
     mbedtls_ssl_context *ssl;

tests/ssl-opt.sh

@@ -8613,7 +8613,6 @@ run_test    "DTLS proxy: 3d, gnutls server, fragmentation, nbio" \
             -s "Extra-header:" \
             -c "Extra-header:"
 
-requires_config_enabled MBEDTLS_SSL_EXPORT_KEYS
 run_test    "export keys functionality" \
             "$P_SRV eap_tls=1 debug_level=3" \
             "$P_CLI eap_tls=1 debug_level=3" \