David Zeuthen | 21e9526 | 2016-07-27 17:58:40 -0400 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2016 The Android Open Source Project |
| 3 | * |
David Zeuthen | c612e2e | 2016-09-16 16:44:08 -0400 | [diff] [blame] | 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: |
David Zeuthen | 21e9526 | 2016-07-27 17:58:40 -0400 | [diff] [blame] | 11 | * |
David Zeuthen | c612e2e | 2016-09-16 16:44:08 -0400 | [diff] [blame] | 12 | * The above copyright notice and this permission notice shall be |
| 13 | * included in all copies or substantial portions of the Software. |
David Zeuthen | 21e9526 | 2016-07-27 17:58:40 -0400 | [diff] [blame] | 14 | * |
David Zeuthen | c612e2e | 2016-09-16 16:44:08 -0400 | [diff] [blame] | 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. |
David Zeuthen | 21e9526 | 2016-07-27 17:58:40 -0400 | [diff] [blame] | 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_DESCRIPTOR_H_ |
| 30 | #define AVB_DESCRIPTOR_H_ |
| 31 | |
| 32 | #include "avb_sysdeps.h" |
| 33 | |
| 34 | #ifdef __cplusplus |
| 35 | extern "C" { |
| 36 | #endif |
| 37 | |
| 38 | /* Well-known descriptor tags. |
| 39 | * |
| 40 | * AVB_DESCRIPTOR_TAG_PROPERTY: see |AvbPropertyDescriptor| struct. |
| 41 | * AVB_DESCRIPTOR_TAG_HASHTREE: see |AvbHashtreeDescriptor| struct. |
| 42 | * AVB_DESCRIPTOR_TAG_HASH: see |AvbHashDescriptor| struct. |
| 43 | * AVB_DESCRIPTOR_TAG_KERNEL_CMDLINE: see |AvbKernelCmdlineDescriptor| struct. |
| 44 | * AVB_DESCRIPTOR_TAG_CHAIN_PARTITION: see |AvbChainPartitionDescriptor| struct. |
| 45 | */ |
| 46 | typedef enum { |
| 47 | AVB_DESCRIPTOR_TAG_PROPERTY, |
| 48 | AVB_DESCRIPTOR_TAG_HASHTREE, |
| 49 | AVB_DESCRIPTOR_TAG_HASH, |
| 50 | AVB_DESCRIPTOR_TAG_KERNEL_CMDLINE, |
| 51 | AVB_DESCRIPTOR_TAG_CHAIN_PARTITION, |
| 52 | } AvbDescriptorTag; |
| 53 | |
| 54 | /* The header for a serialized descriptor. |
| 55 | * |
| 56 | * A descriptor always have two fields, a |tag| (denoting its type, |
| 57 | * see the |AvbDescriptorTag| enumeration) and the size of the bytes |
| 58 | * following, |num_bytes_following|. |
| 59 | * |
| 60 | * For padding, |num_bytes_following| is always a multiple of 8. |
| 61 | */ |
| 62 | typedef struct AvbDescriptor { |
| 63 | uint64_t tag; |
| 64 | uint64_t num_bytes_following; |
| 65 | } AVB_ATTR_PACKED AvbDescriptor; |
| 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_descriptor_validate_and_byteswap( |
| 73 | const AvbDescriptor* src, AvbDescriptor* dest) AVB_ATTR_WARN_UNUSED_RESULT; |
| 74 | |
| 75 | /* Signature for callback function used in avb_descriptor_foreach(). |
| 76 | * The passed in descriptor is given by |descriptor| and the |
| 77 | * |user_data| passed to avb_descriptor_foreach() function is in |
| 78 | * |user_data|. Return true to continue iterating, false to stop |
| 79 | * iterating. |
| 80 | * |
| 81 | * Note that |descriptor| points into the image passed to |
| 82 | * avb_descriptor_foreach() - all fields need to be byteswapped! |
| 83 | */ |
| 84 | typedef bool AvbDescriptorForeachFunc(const AvbDescriptor* descriptor, |
| 85 | void* user_data); |
| 86 | |
| 87 | /* Convenience function to iterate over all descriptors in an vbmeta |
| 88 | * image. |
| 89 | * |
| 90 | * The function given by |foreach_func| will be called for each |
| 91 | * descriptor. The given function should return true to continue |
| 92 | * iterating, false to stop. |
| 93 | * |
| 94 | * The |user_data| parameter will be passed to |foreach_func|. |
| 95 | * |
| 96 | * Returns false if the iteration was short-circuited, that is if |
| 97 | * an invocation of |foreach_func| returned false. |
| 98 | * |
| 99 | * Before using this function, you MUST verify |image_data| with |
| 100 | * avb_vbmeta_image_verify() and reject it unless it's signed by a known |
| 101 | * good public key. Additionally, |image_data| must be word-aligned. |
| 102 | */ |
| 103 | bool avb_descriptor_foreach(const uint8_t* image_data, size_t image_size, |
| 104 | AvbDescriptorForeachFunc foreach_func, |
| 105 | void* user_data); |
| 106 | |
| 107 | /* Gets all descriptors in a vbmeta image. |
| 108 | * |
| 109 | * The return value is a NULL-pointer terminated array of |
| 110 | * AvbDescriptor pointers. Free with avb_free() when you are done with |
| 111 | * it. If |out_num_descriptors| is non-NULL, the number of descriptors |
| 112 | * will be returned there. |
| 113 | * |
| 114 | * Note that each AvbDescriptor pointer in the array points into |
| 115 | * |image_data| - all fields need to be byteswapped! |
| 116 | * |
| 117 | * Before using this function, you MUST verify |image_data| with |
| 118 | * avb_vbmeta_image_verify() and reject it unless it's signed by a known |
| 119 | * good public key. Additionally, |image_data| must be word-aligned. |
| 120 | */ |
| 121 | const AvbDescriptor** avb_descriptor_get_all( |
| 122 | const uint8_t* image_data, size_t image_size, |
| 123 | size_t* out_num_descriptors) AVB_ATTR_WARN_UNUSED_RESULT; |
| 124 | |
| 125 | #ifdef __cplusplus |
| 126 | } |
| 127 | #endif |
| 128 | |
| 129 | #endif /* AVB_DESCRIPTOR_H_ */ |