Remove signature verification from rsa_rsassa_pkcs1_v15_sign
This verification path is redundant now that verification is uniformly done in
rsa_private.
@@ -1311,42 +1311,7 @@ int mbedtls_rsa_rsassa_pkcs1_v15_sign( mbedtls_rsa_context *ctx,
if( mode == MBEDTLS_RSA_PUBLIC )
return( mbedtls_rsa_public( ctx, sig, sig ) );
- /*
- * In order to prevent Lenstra's attack, make the signature in a
- * temporary buffer and check it before returning it.
- */
- sig_try = mbedtls_calloc( 1, ctx->len );
- if( sig_try == NULL )
- return( MBEDTLS_ERR_MPI_ALLOC_FAILED );
-
- verif = mbedtls_calloc( 1, ctx->len );
- if( verif == NULL )
- {
- mbedtls_free( sig_try );
- return( MBEDTLS_ERR_MPI_ALLOC_FAILED );
- }
-
- MBEDTLS_MPI_CHK( mbedtls_rsa_private( ctx, f_rng, p_rng, sig, sig_try ) );
- MBEDTLS_MPI_CHK( mbedtls_rsa_public( ctx, sig_try, verif ) );
-
- /* Compare in constant time just in case */
- for( diff = 0, i = 0; i < ctx->len; i++ )
- diff |= verif[i] ^ sig[i];
- diff_no_optimize = diff;
-
- if( diff_no_optimize != 0 )
- {
- ret = MBEDTLS_ERR_RSA_PRIVATE_FAILED;
- goto cleanup;
- }
-
- memcpy( sig, sig_try, ctx->len );
-
-cleanup:
- mbedtls_free( sig_try );
- mbedtls_free( verif );
-
- return( ret );
+ return( mbedtls_rsa_private( ctx, f_rng, p_rng, sig, sig ) );
}
#endif /* MBEDTLS_PKCS1_V15 */
