mbedtls/tests/include/test/constant_flow.h
Manuel Pégourié-Gonnard 6240defd17 Add MBEDTLS_TEST_CONSTANT_FLOW_MEMSAN
This option allows to test the constant-flow nature of selected code, using
MemSan and the fundamental observation behind ctgrind that the set of
operations allowed on undefined memory by dynamic analysers is the same as the
set of operations allowed on secret data to avoid leaking it to a local
attacker via side channels, namely, any operation except branching and
dereferencing.

(This isn't the full story, as on some CPUs some instructions have variable
execution depending on the inputs, most notably division and on some cores
multiplication. However, testing that no branch or memory access depends on
secret data is already a good start.)

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
2020-07-15 12:26:22 +02:00

52 lines
1.5 KiB
C

/**
* \file constant_flow.h
*
* \brief This file contains tools to ensure tested code has constant flow.
*/
/*
* Copyright (C) 2020, ARM Limited, All Rights Reserved
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* This file is part of mbed TLS (https://tls.mbed.org)
*/
#ifndef TEST_CONSTANT_FLOW_H
#define TEST_CONSTANT_FLOW_H
#if !defined(MBEDTLS_CONFIG_FILE)
#include "mbedtls/config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif
#if defined(MBEDTLS_TEST_CONSTANT_FLOW_MEMSAN)
#include <sanitizer/msan_interface.h>
/* Use macros to avoid messing up with origin tracking */
#define TEST_CF_SECRET __msan_allocated_memory
// void __msan_allocated_memory(const volatile void* data, size_t size);
#define TEST_CF_PUBLIC __msan_unpoison
// void __msan_unpoison(const volatile void *a, size_t size);
#else /* MBEDTLS_TEST_CONSTANT_FLOW_MEMSAN */
#define TEST_CF_SECRET(ptr, size)
#define TEST_CF_PUBLIC(ptr, size)
#endif /* MBEDTLS_TEST_CONSTANT_FLOW_MEMSAN */
#endif /* TEST_CONSTANT_FLOW_H */