1 | #ifndef AWS_COMMON_ZERO_H |
2 | #define AWS_COMMON_ZERO_H |
3 | |
4 | /* |
5 | * Copyright 2010-2019 Amazon.com, Inc. or its affiliates. All Rights Reserved. |
6 | * |
7 | * Licensed under the Apache License, Version 2.0 (the "License"). |
8 | * You may not use this file except in compliance with the License. |
9 | * A copy of the License is located at |
10 | * |
11 | * http://aws.amazon.com/apache2.0 |
12 | * |
13 | * or in the "license" file accompanying this file. This file is distributed |
14 | * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either |
15 | * express or implied. See the License for the specific language governing |
16 | * permissions and limitations under the License. |
17 | */ |
18 | |
19 | #include <aws/common/stdbool.h> |
20 | #include <aws/common/stdint.h> |
21 | |
22 | #include <string.h> |
23 | |
24 | AWS_EXTERN_C_BEGIN |
25 | |
26 | /** |
27 | * Set each byte in the struct to zero. |
28 | */ |
29 | #define AWS_ZERO_STRUCT(object) \ |
30 | do { \ |
31 | memset(&(object), 0, sizeof(object)); \ |
32 | } while (0) |
33 | |
34 | /** |
35 | * Set each byte in the array to zero. |
36 | * Does not work with arrays of unknown bound. |
37 | */ |
38 | #define AWS_ZERO_ARRAY(array) memset((void *)(array), 0, sizeof(array)) |
39 | |
40 | /** |
41 | * Returns whether each byte in the object is zero. |
42 | */ |
43 | #ifdef CBMC |
44 | /* clang-format off */ |
45 | # define AWS_IS_ZEROED(object) \ |
46 | __CPROVER_forall { \ |
47 | int i; \ |
48 | (i >= 0 && i < sizeof(object)) ==> ((const uint8_t *)&object)[i] == 0 \ |
49 | } |
50 | /* clang-format on */ |
51 | #else |
52 | # define AWS_IS_ZEROED(object) aws_is_mem_zeroed(&(object), sizeof(object)) |
53 | #endif |
54 | |
55 | /** |
56 | * Returns whether each byte is zero. |
57 | */ |
58 | AWS_STATIC_IMPL |
59 | bool aws_is_mem_zeroed(const void *buf, size_t bufsize); |
60 | |
61 | /** |
62 | * Securely zeroes a memory buffer. This function will attempt to ensure that |
63 | * the compiler will not optimize away this zeroing operation. |
64 | */ |
65 | AWS_COMMON_API |
66 | void aws_secure_zero(void *pBuf, size_t bufsize); |
67 | |
68 | #ifndef AWS_NO_STATIC_IMPL |
69 | # include <aws/common/zero.inl> |
70 | #endif /* AWS_NO_STATIC_IMPL */ |
71 | |
72 | AWS_EXTERN_C_END |
73 | |
74 | #endif /* AWS_COMMON_ZERO_H */ |
75 | |