mbedtls: Update to upstream version 2.16.6

Fixes https://tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2020-04

7 files changed, 93 insertions, 18 deletions

diff --git a/thirdparty/README.md b/thirdparty/README.md
index 95a6902089..156f8aaea5 100644
--- a/thirdparty/README.md
+++ b/thirdparty/README.md
@@ -302,7 +302,7 @@ changes are marked with `// -- GODOT --` comments.
 ## mbedtls
 
 - Upstream: https://tls.mbed.org/
-- Version: 2.16.5
+- Version: 2.16.6
 - License: Apache 2.0
 
 File extracted from upstream release tarball (`-apache.tgz` variant):
diff --git a/thirdparty/mbedtls/include/mbedtls/check_config.h b/thirdparty/mbedtls/include/mbedtls/check_config.h
index d076c2352f..93de091c4d 100644
--- a/thirdparty/mbedtls/include/mbedtls/check_config.h
+++ b/thirdparty/mbedtls/include/mbedtls/check_config.h
@@ -546,6 +546,23 @@
 #error "MBEDTLS_SSL_PROTO_TLS1_2 defined, but not all prerequisites"
 #endif
 
+#if (defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) ||  \
+     defined(MBEDTLS_SSL_PROTO_TLS1_1) || defined(MBEDTLS_SSL_PROTO_TLS1_2)) && \
+    !(defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) ||                          \
+      defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED) ||                      \
+      defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) ||                    \
+      defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) ||                  \
+      defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) ||                     \
+      defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED) ||                   \
+      defined(MBEDTLS_KEY_EXCHANGE_PSK_ENABLED) ||                          \
+      defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED) ||                      \
+      defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED) ||                      \
+      defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED) ||                    \
+      defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED) )
+#error "One or more versions of the TLS protocol are enabled " \
+        "but no key exchange methods defined with MBEDTLS_KEY_EXCHANGE_xxxx"
+#endif
+
 #if defined(MBEDTLS_SSL_PROTO_DTLS)     && \
     !defined(MBEDTLS_SSL_PROTO_TLS1_1)  && \
     !defined(MBEDTLS_SSL_PROTO_TLS1_2)
@@ -669,6 +686,10 @@
 #error "MBEDTLS_X509_CREATE_C defined, but not all prerequisites"
 #endif
 
+#if defined(MBEDTLS_CERTS_C) && !defined(MBEDTLS_X509_USE_C)
+#error "MBEDTLS_CERTS_C defined, but not all prerequisites"
+#endif
+
 #if defined(MBEDTLS_X509_CRT_PARSE_C) && ( !defined(MBEDTLS_X509_USE_C) )
 #error "MBEDTLS_X509_CRT_PARSE_C defined, but not all prerequisites"
 #endif
diff --git a/thirdparty/mbedtls/include/mbedtls/version.h b/thirdparty/mbedtls/include/mbedtls/version.h
index 8e2ce03c32..e0a2e7f6d6 100644
--- a/thirdparty/mbedtls/include/mbedtls/version.h
+++ b/thirdparty/mbedtls/include/mbedtls/version.h
@@ -40,16 +40,16 @@
  */
 #define MBEDTLS_VERSION_MAJOR  2
 #define MBEDTLS_VERSION_MINOR  16
-#define MBEDTLS_VERSION_PATCH  5
+#define MBEDTLS_VERSION_PATCH  6
 
 /**
  * The single version number has the following structure:
  *    MMNNPP00
  *    Major version | Minor version | Patch version
  */
-#define MBEDTLS_VERSION_NUMBER         0x02100500
-#define MBEDTLS_VERSION_STRING         "2.16.5"
-#define MBEDTLS_VERSION_STRING_FULL    "mbed TLS 2.16.5"
+#define MBEDTLS_VERSION_NUMBER         0x02100600
+#define MBEDTLS_VERSION_STRING         "2.16.6"
+#define MBEDTLS_VERSION_STRING_FULL    "mbed TLS 2.16.6"
 
 #if defined(MBEDTLS_VERSION_C)
 
diff --git a/thirdparty/mbedtls/library/ecp.c b/thirdparty/mbedtls/library/ecp.c
index 040c20bd38..725e176df2 100644
--- a/thirdparty/mbedtls/library/ecp.c
+++ b/thirdparty/mbedtls/library/ecp.c
@@ -1938,6 +1938,20 @@ static int ecp_mul_comb_after_precomp( const mbedtls_ecp_group *grp,
 
 final_norm:
 #endif
+    /*
+     * Knowledge of the jacobian coordinates may leak the last few bits of the
+     * scalar [1], and since our MPI implementation isn't constant-flow,
+     * inversion (used for coordinate normalization) may leak the full value
+     * of its input via side-channels [2].
+     *
+     * [1] https://eprint.iacr.org/2003/191
+     * [2] https://eprint.iacr.org/2020/055
+     *
+     * Avoid the leak by randomizing coordinates before we normalize them.
+     */
+    if( f_rng != 0 )
+        MBEDTLS_MPI_CHK( ecp_randomize_jac( grp, RR, f_rng, p_rng ) );
+
     MBEDTLS_ECP_BUDGET( MBEDTLS_ECP_OPS_INV );
     MBEDTLS_MPI_CHK( ecp_normalize_jac( grp, RR ) );
 
@@ -2308,6 +2322,20 @@ static int ecp_mul_mxz( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
         MBEDTLS_MPI_CHK( mbedtls_mpi_safe_cond_swap( &R->Z, &RP.Z, b ) );
     }
 
+    /*
+     * Knowledge of the projective coordinates may leak the last few bits of the
+     * scalar [1], and since our MPI implementation isn't constant-flow,
+     * inversion (used for coordinate normalization) may leak the full value
+     * of its input via side-channels [2].
+     *
+     * [1] https://eprint.iacr.org/2003/191
+     * [2] https://eprint.iacr.org/2020/055
+     *
+     * Avoid the leak by randomizing coordinates before we normalize them.
+     */
+    if( f_rng != NULL )
+        MBEDTLS_MPI_CHK( ecp_randomize_mxz( grp, R, f_rng, p_rng ) );
+
     MBEDTLS_MPI_CHK( ecp_normalize_mxz( grp, R ) );
 
 cleanup:
diff --git a/thirdparty/mbedtls/library/ssl_cli.c b/thirdparty/mbedtls/library/ssl_cli.c
index afced7a99c..c5c3af69df 100644
--- a/thirdparty/mbedtls/library/ssl_cli.c
+++ b/thirdparty/mbedtls/library/ssl_cli.c
@@ -1417,6 +1417,19 @@ static int ssl_parse_hello_verify_request( mbedtls_ssl_context *ssl )
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse hello verify request" ) );
 
+    /* Check that there is enough room for:
+     * - 2 bytes of version
+     * - 1 byte of cookie_len
+     */
+    if( mbedtls_ssl_hs_hdr_len( ssl ) + 3 > ssl->in_msglen )
+    {
+        MBEDTLS_SSL_DEBUG_MSG( 1,
+            ( "incoming HelloVerifyRequest message is too short" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                    MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
+        return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
+    }
+
     /*
      * struct {
      *   ProtocolVersion server_version;
@@ -1445,8 +1458,6 @@ static int ssl_parse_hello_verify_request( mbedtls_ssl_context *ssl )
     }
 
     cookie_len = *p++;
-    MBEDTLS_SSL_DEBUG_BUF( 3, "cookie", p, cookie_len );
-
     if( ( ssl->in_msg + ssl->in_msglen ) - p < cookie_len )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1,
@@ -1455,6 +1466,7 @@ static int ssl_parse_hello_verify_request( mbedtls_ssl_context *ssl )
                                     MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
         return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
     }
+    MBEDTLS_SSL_DEBUG_BUF( 3, "cookie", p, cookie_len );
 
     mbedtls_free( ssl->handshake->verify_cookie );
 
diff --git a/thirdparty/mbedtls/library/ssl_tls.c b/thirdparty/mbedtls/library/ssl_tls.c
index b8f35fec5d..cbec74fe8c 100644
--- a/thirdparty/mbedtls/library/ssl_tls.c
+++ b/thirdparty/mbedtls/library/ssl_tls.c
@@ -1004,8 +1004,6 @@ int mbedtls_ssl_derive_keys( mbedtls_ssl_context *ssl )
 #if defined(MBEDTLS_SSL_HW_RECORD_ACCEL)
     if( mbedtls_ssl_hw_record_init != NULL )
     {
-        int ret = 0;
-
         MBEDTLS_SSL_DEBUG_MSG( 2, ( "going for mbedtls_ssl_hw_record_init()" ) );
 
         if( ( ret = mbedtls_ssl_hw_record_init( ssl, key1, key2, transform->keylen,
@@ -2885,15 +2883,18 @@ static void ssl_dtls_replay_reset( mbedtls_ssl_context *ssl );
 /*
  * Swap transform_out and out_ctr with the alternative ones
  */
-static void ssl_swap_epochs( mbedtls_ssl_context *ssl )
+static int ssl_swap_epochs( mbedtls_ssl_context *ssl )
 {
     mbedtls_ssl_transform *tmp_transform;
     unsigned char tmp_out_ctr[8];
+#if defined(MBEDTLS_SSL_HW_RECORD_ACCEL)
+    int ret;
+#endif /* MBEDTLS_SSL_HW_RECORD_ACCEL */
 
     if( ssl->transform_out == ssl->handshake->alt_transform_out )
     {
         MBEDTLS_SSL_DEBUG_MSG( 3, ( "skip swap epochs" ) );
-        return;
+        return( 0 );
     }
 
     MBEDTLS_SSL_DEBUG_MSG( 3, ( "swap epochs" ) );
@@ -2920,7 +2921,9 @@ static void ssl_swap_epochs( mbedtls_ssl_context *ssl )
             return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );
         }
     }
-#endif
+#endif /* MBEDTLS_SSL_HW_RECORD_ACCEL */
+
+    return( 0 );
 }
 
 /*
@@ -2957,7 +2960,8 @@ int mbedtls_ssl_flight_transmit( mbedtls_ssl_context *ssl )
 
         ssl->handshake->cur_msg = ssl->handshake->flight;
         ssl->handshake->cur_msg_p = ssl->handshake->flight->p + 12;
-        ssl_swap_epochs( ssl );
+        if( ( ret = ssl_swap_epochs( ssl ) ) != 0 )
+            return( ret );
 
         ssl->handshake->retransmit_state = MBEDTLS_SSL_RETRANS_SENDING;
     }
@@ -2980,7 +2984,8 @@ int mbedtls_ssl_flight_transmit( mbedtls_ssl_context *ssl )
         if( is_finished && ssl->handshake->cur_msg_p == ( cur->p + 12 ) )
         {
             MBEDTLS_SSL_DEBUG_MSG( 2, ( "swap epochs to send finished message" ) );
-            ssl_swap_epochs( ssl );
+            if( ( ret = ssl_swap_epochs( ssl ) ) != 0 )
+                return( ret );
         }
 
         ret = ssl_get_remaining_payload_in_datagram( ssl );
@@ -3017,7 +3022,10 @@ int mbedtls_ssl_flight_transmit( mbedtls_ssl_context *ssl )
             if( ( max_frag_len < 12 ) || ( max_frag_len == 12 && hs_len != 0 ) )
             {
                 if( is_finished )
-                    ssl_swap_epochs( ssl );
+                {
+                    if( ( ret = ssl_swap_epochs( ssl ) ) != 0 )
+                        return( ret );
+                }
 
                 if( ( ret = mbedtls_ssl_flush_output( ssl ) ) != 0 )
                     return( ret );
@@ -3997,17 +4005,23 @@ static int ssl_handle_possible_reconnect( mbedtls_ssl_context *ssl )
 
     if( ret == MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED )
     {
+        int send_ret;
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "sending HelloVerifyRequest" ) );
+        MBEDTLS_SSL_DEBUG_BUF( 4, "output record sent to network",
+                                  ssl->out_buf, len );
         /* Don't check write errors as we can't do anything here.
          * If the error is permanent we'll catch it later,
          * if it's not, then hopefully it'll work next time. */
-        (void) ssl->f_send( ssl->p_bio, ssl->out_buf, len );
+        send_ret = ssl->f_send( ssl->p_bio, ssl->out_buf, len );
+        MBEDTLS_SSL_DEBUG_RET( 2, "ssl->f_send", send_ret );
+        (void) send_ret;
 
         return( MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED );
     }
 
     if( ret == 0 )
     {
-        /* Got a valid cookie, partially reset context */
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "cookie is valid, resetting context" ) );
         if( ( ret = ssl_session_reset_int( ssl, 1 ) ) != 0 )
         {
             MBEDTLS_SSL_DEBUG_RET( 1, "reset", ret );
diff --git a/thirdparty/mbedtls/library/x509.c b/thirdparty/mbedtls/library/x509.c
index 2e0b0e8f6c..4d25303206 100644
--- a/thirdparty/mbedtls/library/x509.c
+++ b/thirdparty/mbedtls/library/x509.c
@@ -1063,7 +1063,7 @@ cleanup:
     mbedtls_x509_crt_free( &clicert );
 #else
     ((void) verbose);
-#endif /* MBEDTLS_CERTS_C && MBEDTLS_SHA1_C */
+#endif /* MBEDTLS_CERTS_C && MBEDTLS_SHA256_C */
     return( ret );
 }