1 /* 2 * Copyright (C) 2016 The Android Open Source Project 3 * 4 * SPDX-License-Identifier: MIT 5 */ 6 7 #if !defined(AVB_INSIDE_LIBAVB_H) && !defined(AVB_COMPILATION) 8 #error "Never include this file directly, include libavb.h instead." 9 #endif 10 11 #ifndef AVB_HASHTREE_DESCRIPTOR_H_ 12 #define AVB_HASHTREE_DESCRIPTOR_H_ 13 14 #include "avb_descriptor.h" 15 16 #ifdef __cplusplus 17 extern "C" { 18 #endif 19 20 /* Flags for hashtree descriptors. 21 * 22 * AVB_HASHTREE_DESCRIPTOR_FLAGS_DO_NOT_USE_AB: Do not apply the default A/B 23 * partition logic to this partition. This is intentionally a negative boolean 24 * because A/B should be both the default and most used in practice. 25 */ 26 typedef enum { 27 AVB_HASHTREE_DESCRIPTOR_FLAGS_DO_NOT_USE_AB = (1 << 0), 28 } AvbHashtreeDescriptorFlags; 29 30 /* A descriptor containing information about a dm-verity hashtree. 31 * 32 * Hash-trees are used to verify large partitions typically containing 33 * file systems. See 34 * https://gitlab.com/cryptsetup/cryptsetup/wikis/DMVerity for more 35 * information about dm-verity. 36 * 37 * Following this struct are |partition_name_len| bytes of the 38 * partition name (UTF-8 encoded), |salt_len| bytes of salt, and then 39 * |root_digest_len| bytes of the root digest. 40 * 41 * The |reserved| field is for future expansion and must be set to NUL 42 * bytes. 43 * 44 * Changes in v1.1: 45 * - flags field is added which supports AVB_HASHTREE_DESCRIPTOR_FLAGS_USE_AB 46 * - digest_len may be zero, which indicates the use of a persistent digest 47 */ 48 typedef struct AvbHashtreeDescriptor { 49 AvbDescriptor parent_descriptor; 50 uint32_t dm_verity_version; 51 uint64_t image_size; 52 uint64_t tree_offset; 53 uint64_t tree_size; 54 uint32_t data_block_size; 55 uint32_t hash_block_size; 56 uint32_t fec_num_roots; 57 uint64_t fec_offset; 58 uint64_t fec_size; 59 uint8_t hash_algorithm[32]; 60 uint32_t partition_name_len; 61 uint32_t salt_len; 62 uint32_t root_digest_len; 63 uint32_t flags; 64 uint8_t reserved[60]; 65 } AVB_ATTR_PACKED AvbHashtreeDescriptor; 66 67 /* Copies |src| to |dest| and validates, byte-swapping fields in the 68 * process if needed. Returns true if valid, false if invalid. 69 * 70 * Data following the struct is not validated nor copied. 71 */ 72 bool avb_hashtree_descriptor_validate_and_byteswap( 73 const AvbHashtreeDescriptor* src, 74 AvbHashtreeDescriptor* dest) AVB_ATTR_WARN_UNUSED_RESULT; 75 76 #ifdef __cplusplus 77 } 78 #endif 79 80 #endif /* AVB_HASHTREE_DESCRIPTOR_H_ */ 81