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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_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