Merge remote-tracking branch 'public/pr/2095' into development-proposed

4 files changed, 19 insertions, 12 deletions

diff --git a/ChangeLog b/ChangeLog
index 7e1955ae..40df6f2d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -34,6 +34,10 @@ Bugfix
      program programs/x509/cert_write. Fixes #1422.
    * Ignore IV in mbedtls_cipher_set_iv() when the cipher mode is MBEDTLS_MODE_ECB
      Fix for #1091 raised by ezdevelop
+   * Zeroize memory used for buffering or reassembling handshake messages
+     after use.
+   * Use `mbedtls_platform_zeroize()` instead of `memset()` for zeroization
+     of sensitive data in the example programs aescrypt2 and crypt_and_hash.
 
 Changes
    * Removed support for Yotta as a build tool.
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index bf43e889..82e65251 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -8801,6 +8801,7 @@ static void ssl_buffering_free_slot( mbedtls_ssl_context *ssl,
     if( hs_buf->is_valid == 1 )
     {
         hs->buffering.total_bytes_buffered -= hs_buf->data_len;
+        mbedtls_platform_zeroize( hs_buf->data, hs_buf->data_len );
         mbedtls_free( hs_buf->data );
         memset( hs_buf, 0, sizeof( mbedtls_ssl_hs_buffer ) );
     }
diff --git a/programs/aes/aescrypt2.c b/programs/aes/aescrypt2.c
index 69c40600..5725eb0f 100644
--- a/programs/aes/aescrypt2.c
+++ b/programs/aes/aescrypt2.c
@@ -43,6 +43,7 @@
 
 #include "mbedtls/aes.h"
 #include "mbedtls/md.h"
+#include "mbedtls/platform_util.h"
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -450,13 +451,13 @@ exit:
        the case when the user has missed or reordered some,
        in which case the key might not be in argv[4]. */
     for( i = 0; i < (unsigned int) argc; i++ )
-        memset( argv[i], 0, strlen( argv[i] ) );
+        mbedtls_platform_zeroize( argv[i], strlen( argv[i] ) );
 
-    memset( IV,     0, sizeof( IV ) );
-    memset( key,    0, sizeof( key ) );
-    memset( tmp,    0, sizeof( tmp ) );
-    memset( buffer, 0, sizeof( buffer ) );
-    memset( digest, 0, sizeof( digest ) );
+    mbedtls_platform_zeroize( IV,     sizeof( IV ) );
+    mbedtls_platform_zeroize( key,    sizeof( key ) );
+    mbedtls_platform_zeroize( tmp,    sizeof( tmp ) );
+    mbedtls_platform_zeroize( buffer, sizeof( buffer ) );
+    mbedtls_platform_zeroize( digest, sizeof( digest ) );
 
     mbedtls_aes_free( &aes_ctx );
     mbedtls_md_free( &sha_ctx );
diff --git a/programs/aes/crypt_and_hash.c b/programs/aes/crypt_and_hash.c
index bc95eb9b..88b852b4 100644
--- a/programs/aes/crypt_and_hash.c
+++ b/programs/aes/crypt_and_hash.c
@@ -46,6 +46,7 @@
  defined(MBEDTLS_FS_IO)
 #include "mbedtls/cipher.h"
 #include "mbedtls/md.h"
+#include "mbedtls/platform_util.h"
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -547,13 +548,13 @@ exit:
        the case when the user has missed or reordered some,
        in which case the key might not be in argv[6]. */
     for( i = 0; i < argc; i++ )
-        memset( argv[i], 0, strlen( argv[i] ) );
+        mbedtls_platform_zeroize( argv[i], strlen( argv[i] ) );
 
-    memset( IV,     0, sizeof( IV ) );
-    memset( key,    0, sizeof( key ) );
-    memset( buffer, 0, sizeof( buffer ) );
-    memset( output, 0, sizeof( output ) );
-    memset( digest, 0, sizeof( digest ) );
+    mbedtls_platform_zeroize( IV,     sizeof( IV ) );
+    mbedtls_platform_zeroize( key,    sizeof( key ) );
+    mbedtls_platform_zeroize( buffer, sizeof( buffer ) );
+    mbedtls_platform_zeroize( output, sizeof( output ) );
+    mbedtls_platform_zeroize( digest, sizeof( digest ) );
 
     mbedtls_cipher_free( &cipher_ctx );
     mbedtls_md_free( &md_ctx );