1/**
2 * \file constant_flow.h
3 *
4 * \brief   This file contains tools to ensure tested code has constant flow.
5 */
6
7/*
8 *  Copyright The Mbed TLS Contributors
9 *  SPDX-License-Identifier: Apache-2.0
10 *
11 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
12 *  not use this file except in compliance with the License.
13 *  You may obtain a copy of the License at
14 *
15 *  http://www.apache.org/licenses/LICENSE-2.0
16 *
17 *  Unless required by applicable law or agreed to in writing, software
18 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
19 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
20 *  See the License for the specific language governing permissions and
21 *  limitations under the License.
22 */
23
24#ifndef TEST_CONSTANT_FLOW_H
25#define TEST_CONSTANT_FLOW_H
26
27#include "mbedtls/build_info.h"
28
29/*
30 * This file defines the two macros
31 *
32 *  #define TEST_CF_SECRET(ptr, size)
33 *  #define TEST_CF_PUBLIC(ptr, size)
34 *
35 * that can be used in tests to mark a memory area as secret (no branch or
36 * memory access should depend on it) or public (default, only needs to be
37 * marked explicitly when it was derived from secret data).
38 *
39 * Arguments:
40 * - ptr: a pointer to the memory area to be marked
41 * - size: the size in bytes of the memory area
42 *
43 * Implementation:
44 * The basic idea is that of ctgrind <https://github.com/agl/ctgrind>: we can
45 * re-use tools that were designed for checking use of uninitialized memory.
46 * This file contains two implementations: one based on MemorySanitizer, the
47 * other on valgrind's memcheck. If none of them is enabled, dummy macros that
48 * do nothing are defined for convenience.
49 *
50 * \note #TEST_CF_SECRET must be called directly from within a .function file,
51 *       not indirectly via a macro defined under tests/include or a function
52 *       under tests/src. This is because we only run Valgrind for constant
53 *       flow on test suites that have greppable annotations inside them (see
54 *       `skip_suites_without_constant_flow` in `tests/scripts/all.sh`).
55 */
56
57#if defined(MBEDTLS_TEST_CONSTANT_FLOW_MEMSAN)
58#include <sanitizer/msan_interface.h>
59
60/* Use macros to avoid messing up with origin tracking */
61#define TEST_CF_SECRET  __msan_allocated_memory
62// void __msan_allocated_memory(const volatile void* data, size_t size);
63#define TEST_CF_PUBLIC  __msan_unpoison
64// void __msan_unpoison(const volatile void *a, size_t size);
65
66#elif defined(MBEDTLS_TEST_CONSTANT_FLOW_VALGRIND)
67#include <valgrind/memcheck.h>
68
69#define TEST_CF_SECRET  VALGRIND_MAKE_MEM_UNDEFINED
70// VALGRIND_MAKE_MEM_UNDEFINED(_qzz_addr, _qzz_len)
71#define TEST_CF_PUBLIC  VALGRIND_MAKE_MEM_DEFINED
72// VALGRIND_MAKE_MEM_DEFINED(_qzz_addr, _qzz_len)
73
74#else /* MBEDTLS_TEST_CONSTANT_FLOW_MEMSAN ||
75         MBEDTLS_TEST_CONSTANT_FLOW_VALGRIND */
76
77#define TEST_CF_SECRET(ptr, size)
78#define TEST_CF_PUBLIC(ptr, size)
79
80#endif /* MBEDTLS_TEST_CONSTANT_FLOW_MEMSAN ||
81          MBEDTLS_TEST_CONSTANT_FLOW_VALGRIND */
82
83#endif /* TEST_CONSTANT_FLOW_H */
84