Merge remote-tracking branch 'public/pr/1957' into mbedtls-2.1
diff --git a/ChangeLog b/ChangeLog
index 717079e..19180e9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -10,6 +10,11 @@
    * Add ecc extensions only if an ecc based ciphersuite is used.
      This improves compliance to RFC 4492, and as a result, solves
      interoperability issues with BouncyCastle. Raised by milenamil in #1157.
+   * Fix potential use-after-free in mbedtls_ssl_get_max_frag_len()
+     and mbedtls_ssl_get_record_expansion() after a session reset. Fixes #1941.
+   * Fix a miscalculation of the maximum record expansion in
+     mbedtls_ssl_get_record_expansion() in case of CBC ciphersuites
+     in (D)TLS versions 1.1 or higher. Fixes #1914.
    * Fix a bug that caused SSL/TLS clients to incorrectly abort the handshake
      with TLS versions 1.1 and earlier when the server requested authentication
      without providing a list of CAs. This was due to an overly strict bounds
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index c7ccac4..d5c1e62 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -5737,6 +5737,9 @@
     ssl->transform_in = NULL;
     ssl->transform_out = NULL;
 
+    ssl->session_in = NULL;
+    ssl->session_out = NULL;
+
     memset( ssl->out_buf, 0, MBEDTLS_SSL_BUFFER_LEN );
     if( partial == 0 )
         memset( ssl->in_buf, 0, MBEDTLS_SSL_BUFFER_LEN );
@@ -6448,17 +6451,18 @@
 
 int mbedtls_ssl_get_record_expansion( const mbedtls_ssl_context *ssl )
 {
-    size_t transform_expansion;
+    size_t transform_expansion = 0;
     const mbedtls_ssl_transform *transform = ssl->transform_out;
+    unsigned block_size;
+
+    if( transform == NULL )
+        return( (int) mbedtls_ssl_hdr_len( ssl ) );
 
 #if defined(MBEDTLS_ZLIB_SUPPORT)
     if( ssl->session_out->compression != MBEDTLS_SSL_COMPRESS_NULL )
         return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
 #endif
 
-    if( transform == NULL )
-        return( (int) mbedtls_ssl_hdr_len( ssl ) );
-
     switch( mbedtls_cipher_get_cipher_mode( &transform->cipher_ctx_enc ) )
     {
         case MBEDTLS_MODE_GCM:
@@ -6468,8 +6472,25 @@
             break;
 
         case MBEDTLS_MODE_CBC:
-            transform_expansion = transform->maclen
-                      + mbedtls_cipher_get_block_size( &transform->cipher_ctx_enc );
+
+            block_size = mbedtls_cipher_get_block_size(
+                &transform->cipher_ctx_enc );
+
+            /* Expansion due to the addition of the MAC. */
+            transform_expansion += transform->maclen;
+
+            /* Expansion due to the addition of CBC padding;
+             * Theoretically up to 256 bytes, but we never use
+             * more than the block size of the underlying cipher. */
+            transform_expansion += block_size;
+
+            /* For TLS 1.1 or higher, an explicit IV is added
+             * after the record header. */
+#if defined(MBEDTLS_SSL_PROTO_TLS1_1) || defined(MBEDTLS_SSL_PROTO_TLS1_2)
+            if( ssl->minor_ver >= MBEDTLS_SSL_MINOR_VERSION_2 )
+                transform_expansion += block_size;
+#endif /* MBEDTLS_SSL_PROTO_TLS1_1 || MBEDTLS_SSL_PROTO_TLS1_2 */
+
             break;
 
         default:
diff --git a/programs/ssl/ssl_mail_client.c b/programs/ssl/ssl_mail_client.c
index ef68f24..f9a3bc6 100644
--- a/programs/ssl/ssl_mail_client.c
+++ b/programs/ssl/ssl_mail_client.c
@@ -345,9 +345,15 @@
 {
     int ret = 0, len;
     mbedtls_net_context server_fd;
-    unsigned char buf[1024];
 #if defined(MBEDTLS_BASE64_C)
     unsigned char base[1024];
+    /* buf is used as the destination buffer for printing base with the format:
+     * "%s\r\n". Hence, the size of buf should be at least the size of base
+     * plus 2 bytes for the \r and \n characters.
+     */
+    unsigned char buf[sizeof( base ) + 2];
+#else
+    unsigned char buf[1024];
 #endif
     char hostname[32];
     const char *pers = "ssl_mail_client";
diff --git a/programs/x509/cert_write.c b/programs/x509/cert_write.c
index 9cc582d..e4f3643 100644
--- a/programs/x509/cert_write.c
+++ b/programs/x509/cert_write.c
@@ -161,7 +161,7 @@
     const char *issuer_key;     /* filename of the issuer key file      */
     const char *subject_pwd;    /* password for the subject key file    */
     const char *issuer_pwd;     /* password for the issuer key file     */
-    const char *output_file;    /* where to store the constructed key file  */
+    const char *output_file;    /* where to store the constructed CRT   */
     const char *subject_name;   /* subject name for certificate         */
     const char *issuer_name;    /* issuer name for certificate          */
     const char *not_before;     /* validity period not before           */
@@ -772,7 +772,7 @@
     }
 
     /*
-     * 1.2. Writing the request
+     * 1.2. Writing the certificate
      */
     mbedtls_printf( "  . Writing the certificate..." );
     fflush( stdout );