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      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
     35 extern "C" {
     36 #endif
     37 
     38 /* A descriptor containing information about a dm-verity hashtree.
     39  *
     40  * Hash-trees are used to verify large partitions typically containing
     41  * file systems. See
     42  * https://gitlab.com/cryptsetup/cryptsetup/wikis/DMVerity for more
     43  * information about dm-verity.
     44  *
     45  * Following this struct are |partition_name_len| bytes of the
     46  * partition name (UTF-8 encoded), |salt_len| bytes of salt, and then
     47  * |root_digest_len| bytes of the root digest.
     48  *
     49  * The |reserved| field is for future expansion and must be set to NUL
     50  * bytes.
     51  */
     52 typedef struct AvbHashtreeDescriptor {
     53   AvbDescriptor parent_descriptor;
     54   uint32_t dm_verity_version;
     55   uint64_t image_size;
     56   uint64_t tree_offset;
     57   uint64_t tree_size;
     58   uint32_t data_block_size;
     59   uint32_t hash_block_size;
     60   uint32_t fec_num_roots;
     61   uint64_t fec_offset;
     62   uint64_t fec_size;
     63   uint8_t hash_algorithm[32];
     64   uint32_t partition_name_len;
     65   uint32_t salt_len;
     66   uint32_t root_digest_len;
     67   uint8_t reserved[64];
     68 } AVB_ATTR_PACKED AvbHashtreeDescriptor;
     69 
     70 /* Copies |src| to |dest| and validates, byte-swapping fields in the
     71  * process if needed. Returns true if valid, false if invalid.
     72  *
     73  * Data following the struct is not validated nor copied.
     74  */
     75 bool avb_hashtree_descriptor_validate_and_byteswap(
     76     const AvbHashtreeDescriptor* src,
     77     AvbHashtreeDescriptor* dest) AVB_ATTR_WARN_UNUSED_RESULT;
     78 
     79 #ifdef __cplusplus
     80 }
     81 #endif
     82 
     83 #endif /* AVB_HASHTREE_DESCRIPTOR_H_ */
     84