Zeroize sensitive data in aescrypt2 and crypt_and_hash examples

This commit replaces multiple `memset()` calls in the example
programs aes/aescrypt2.c and aes/crypt_and_hash.c by calls to
the reliable zeroization function `mbedtls_zeroize()`.

While not a security issue because the code is in the example
programs, it's bad practice and should be fixed.
This commit is contained in:
Hanno Becker 2018-10-12 16:46:37 +01:00
parent 7a539a57d7
commit 9a1a151a1a
2 changed files with 24 additions and 12 deletions

View File

@ -72,6 +72,12 @@ int main( void )
return( 0 );
}
#else
/* Implementation that should never be optimized out by the compiler */
static void mbedtls_zeroize( void *v, size_t n ) {
volatile unsigned char *p = v; while( n-- ) *p++ = 0;
}
int main( int argc, char *argv[] )
{
int ret = 0;
@ -445,13 +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_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_zeroize( IV, sizeof( IV ) );
mbedtls_zeroize( key, sizeof( key ) );
mbedtls_zeroize( tmp, sizeof( tmp ) );
mbedtls_zeroize( buffer, sizeof( buffer ) );
mbedtls_zeroize( digest, sizeof( digest ) );
mbedtls_aes_free( &aes_ctx );
mbedtls_md_free( &sha_ctx );

View File

@ -74,6 +74,12 @@ int main( void )
return( 0 );
}
#else
/* Implementation that should never be optimized out by the compiler */
static void mbedtls_zeroize( void *v, size_t n ) {
volatile unsigned char *p = v; while( n-- ) *p++ = 0;
}
int main( int argc, char *argv[] )
{
int ret = 1, i, n;
@ -542,13 +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_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_zeroize( IV, sizeof( IV ) );
mbedtls_zeroize( key, sizeof( key ) );
mbedtls_zeroize( buffer, sizeof( buffer ) );
mbedtls_zeroize( output, sizeof( output ) );
mbedtls_zeroize( digest, sizeof( digest ) );
mbedtls_cipher_free( &cipher_ctx );
mbedtls_md_free( &md_ctx );