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_HASHTREE_DESCRIPTOR_H_
30#define AVB_HASHTREE_DESCRIPTOR_H_
31
32#include "avb_descriptor.h"
33
34#ifdef __cplusplus
35extern "C" {
36#endif
37
38/* Flags for hashtree descriptors.
39 *
40 * AVB_HASHTREE_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 */
44typedef enum {
45  AVB_HASHTREE_DESCRIPTOR_FLAGS_DO_NOT_USE_AB = (1 << 0),
46} AvbHashtreeDescriptorFlags;
47
48/* A descriptor containing information about a dm-verity hashtree.
49 *
50 * Hash-trees are used to verify large partitions typically containing
51 * file systems. See
52 * https://gitlab.com/cryptsetup/cryptsetup/wikis/DMVerity for more
53 * information about dm-verity.
54 *
55 * Following this struct are |partition_name_len| bytes of the
56 * partition name (UTF-8 encoded), |salt_len| bytes of salt, and then
57 * |root_digest_len| bytes of the root digest.
58 *
59 * The |reserved| field is for future expansion and must be set to NUL
60 * bytes.
61 *
62 * Changes in v1.1:
63 *   - flags field is added which supports AVB_HASHTREE_DESCRIPTOR_FLAGS_USE_AB
64 *   - digest_len may be zero, which indicates the use of a persistent digest
65 */
66typedef struct AvbHashtreeDescriptor {
67  AvbDescriptor parent_descriptor;
68  uint32_t dm_verity_version;
69  uint64_t image_size;
70  uint64_t tree_offset;
71  uint64_t tree_size;
72  uint32_t data_block_size;
73  uint32_t hash_block_size;
74  uint32_t fec_num_roots;
75  uint64_t fec_offset;
76  uint64_t fec_size;
77  uint8_t hash_algorithm[32];
78  uint32_t partition_name_len;
79  uint32_t salt_len;
80  uint32_t root_digest_len;
81  uint32_t flags;
82  uint8_t reserved[60];
83} AVB_ATTR_PACKED AvbHashtreeDescriptor;
84
85/* Copies |src| to |dest| and validates, byte-swapping fields in the
86 * process if needed. Returns true if valid, false if invalid.
87 *
88 * Data following the struct is not validated nor copied.
89 */
90bool avb_hashtree_descriptor_validate_and_byteswap(
91    const AvbHashtreeDescriptor* src,
92    AvbHashtreeDescriptor* dest) AVB_ATTR_WARN_UNUSED_RESULT;
93
94#ifdef __cplusplus
95}
96#endif
97
98#endif /* AVB_HASHTREE_DESCRIPTOR_H_ */
99