avb_hashtree_descriptor.h
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/* SPDX-License-Identifier: MIT */
/*
* Copyright (C) 2016 The Android Open Source Project
*/
#if !defined(AVB_INSIDE_LIBAVB_H) && !defined(AVB_COMPILATION)
#error "Never include this file directly, include libavb.h instead."
#endif
#ifndef AVB_HASHTREE_DESCRIPTOR_H_
#define AVB_HASHTREE_DESCRIPTOR_H_
#include "avb_descriptor.h"
#ifdef __cplusplus
extern "C" {
#endif
/* Flags for hashtree descriptors.
*
* AVB_HASHTREE_DESCRIPTOR_FLAGS_DO_NOT_USE_AB: Do not apply the default A/B
* partition logic to this partition. This is intentionally a negative boolean
* because A/B should be both the default and most used in practice.
*/
typedef enum {
AVB_HASHTREE_DESCRIPTOR_FLAGS_DO_NOT_USE_AB = (1 << 0),
} AvbHashtreeDescriptorFlags;
/* A descriptor containing information about a dm-verity hashtree.
*
* Hash-trees are used to verify large partitions typically containing
* file systems. See
* https://gitlab.com/cryptsetup/cryptsetup/wikis/DMVerity for more
* information about dm-verity.
*
* Following this struct are |partition_name_len| bytes of the
* partition name (UTF-8 encoded), |salt_len| bytes of salt, and then
* |root_digest_len| bytes of the root digest.
*
* The |reserved| field is for future expansion and must be set to NUL
* bytes.
*
* Changes in v1.1:
* - flags field is added which supports AVB_HASHTREE_DESCRIPTOR_FLAGS_USE_AB
* - digest_len may be zero, which indicates the use of a persistent digest
*/
typedef struct AvbHashtreeDescriptor {
AvbDescriptor parent_descriptor;
uint32_t dm_verity_version;
uint64_t image_size;
uint64_t tree_offset;
uint64_t tree_size;
uint32_t data_block_size;
uint32_t hash_block_size;
uint32_t fec_num_roots;
uint64_t fec_offset;
uint64_t fec_size;
uint8_t hash_algorithm[32];
uint32_t partition_name_len;
uint32_t salt_len;
uint32_t root_digest_len;
uint32_t flags;
uint8_t reserved[60];
} AVB_ATTR_PACKED AvbHashtreeDescriptor;
/* Copies |src| to |dest| and validates, byte-swapping fields in the
* process if needed. Returns true if valid, false if invalid.
*
* Data following the struct is not validated nor copied.
*/
bool avb_hashtree_descriptor_validate_and_byteswap(
const AvbHashtreeDescriptor* src,
AvbHashtreeDescriptor* dest) AVB_ATTR_WARN_UNUSED_RESULT;
#ifdef __cplusplus
}
#endif
#endif /* AVB_HASHTREE_DESCRIPTOR_H_ */