Zeroize stack before returning from mpi_fill_random
@@ -63,6 +63,11 @@ static void mbedtls_mpi_zeroize( mbedtls_mpi_uint *v, size_t n ) {
volatile mbedtls_mpi_uint *p = v; while( n-- ) *p++ = 0;
}
+/* 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;
+}
+
#define ciL (sizeof(mbedtls_mpi_uint)) /* chars in limb */
#define biL (ciL << 3) /* bits in limb */
#define biH (ciL << 2) /* half limb size */
@@ -1886,6 +1891,7 @@ int mbedtls_mpi_fill_random( mbedtls_mpi *X, size_t size,
MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( X, buf, size ) );
cleanup:
+ mbedtls_zeroize( buf, sizeof( buf ) );
return( ret );
}
