1 /*
2  * Copyright (C) 2016 The Android Open Source Project
3  *
4  * Permission is hereby granted, free of charge, to any person
5  * obtaining a copy of this software and associated documentation
6  * files (the "Software"), to deal in the Software without
7  * restriction, including without limitation the rights to use, copy,
8  * modify, merge, publish, distribute, sublicense, and/or sell copies
9  * of the Software, and to permit persons to whom the Software is
10  * furnished to do so, subject to the following conditions:
11  *
12  * The above copyright notice and this permission notice shall be
13  * included in all copies or substantial portions of the Software.
14  *
15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
18  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
19  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
20  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
21  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22  * SOFTWARE.
23  */
24 
25 #if !defined(AVB_INSIDE_LIBAVB_H) && !defined(AVB_COMPILATION)
26 #error "Never include this file directly, include libavb.h instead."
27 #endif
28 
29 #ifndef AVB_HASH_DESCRIPTOR_H_
30 #define AVB_HASH_DESCRIPTOR_H_
31 
32 #include "avb_descriptor.h"
33 
34 #ifdef __cplusplus
35 extern "C" {
36 #endif
37 
38 /* Flags for hash descriptors.
39  *
40  * AVB_HASH_DESCRIPTOR_FLAGS_DO_NOT_USE_AB: Do not apply the default A/B
41  *   partition logic to this partition. This is intentionally a negative boolean
42  *   because A/B should be both the default and most used in practice.
43  */
44 typedef enum {
45   AVB_HASH_DESCRIPTOR_FLAGS_DO_NOT_USE_AB = (1 << 0),
46 } AvbHashDescriptorFlags;
47 
48 /* A descriptor containing information about hash for an image.
49  *
50  * This descriptor is typically used for boot partitions to verify the
51  * entire kernel+initramfs image before executing it.
52  *
53  * Following this struct are |partition_name_len| bytes of the
54  * partition name (UTF-8 encoded), |salt_len| bytes of salt, and then
55  * |digest_len| bytes of the digest.
56  *
57  * The |reserved| field is for future expansion and must be set to NUL
58  * bytes.
59  *
60  * Changes in v1.1:
61  *   - flags field is added which supports AVB_HASH_DESCRIPTOR_FLAGS_USE_AB
62  *   - digest_len may be zero, which indicates the use of a persistent digest
63  */
64 typedef struct AvbHashDescriptor {
65   AvbDescriptor parent_descriptor;
66   uint64_t image_size;
67   uint8_t hash_algorithm[32];
68   uint32_t partition_name_len;
69   uint32_t salt_len;
70   uint32_t digest_len;
71   uint32_t flags;
72   uint8_t reserved[60];
73 } AVB_ATTR_PACKED AvbHashDescriptor;
74 
75 /* Copies |src| to |dest| and validates, byte-swapping fields in the
76  * process if needed. Returns true if valid, false if invalid.
77  *
78  * Data following the struct is not validated nor copied.
79  */
80 bool avb_hash_descriptor_validate_and_byteswap(const AvbHashDescriptor* src,
81                                                AvbHashDescriptor* dest)
82     AVB_ATTR_WARN_UNUSED_RESULT;
83 
84 #ifdef __cplusplus
85 }
86 #endif
87 
88 #endif /* AVB_HASH_DESCRIPTOR_H_ */
89