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 /* 26 #if !defined(AVB_INSIDE_LIBAVB_H) && !defined(AVB_COMPILATION) 27 #error "Never include this file directly, include libavb.h instead." 28 #endif 29 */ 30 31 #ifndef AVB_DESCRIPTOR_H_ 32 #define AVB_DESCRIPTOR_H_ 33 34 #include <android_avb/avb_sysdeps.h> 35 36 #ifdef __cplusplus 37 extern "C" { 38 #endif 39 40 /* Well-known descriptor tags. 41 * 42 * AVB_DESCRIPTOR_TAG_PROPERTY: see |AvbPropertyDescriptor| struct. 43 * AVB_DESCRIPTOR_TAG_HASHTREE: see |AvbHashtreeDescriptor| struct. 44 * AVB_DESCRIPTOR_TAG_HASH: see |AvbHashDescriptor| struct. 45 * AVB_DESCRIPTOR_TAG_KERNEL_CMDLINE: see |AvbKernelCmdlineDescriptor| struct. 46 * AVB_DESCRIPTOR_TAG_CHAIN_PARTITION: see |AvbChainPartitionDescriptor| struct. 47 */ 48 typedef enum { 49 AVB_DESCRIPTOR_TAG_PROPERTY, 50 AVB_DESCRIPTOR_TAG_HASHTREE, 51 AVB_DESCRIPTOR_TAG_HASH, 52 AVB_DESCRIPTOR_TAG_KERNEL_CMDLINE, 53 AVB_DESCRIPTOR_TAG_CHAIN_PARTITION, 54 } AvbDescriptorTag; 55 56 /* The header for a serialized descriptor. 57 * 58 * A descriptor always have two fields, a |tag| (denoting its type, 59 * see the |AvbDescriptorTag| enumeration) and the size of the bytes 60 * following, |num_bytes_following|. 61 * 62 * For padding, |num_bytes_following| is always a multiple of 8. 63 */ 64 typedef struct AvbDescriptor { 65 uint64_t tag; 66 uint64_t num_bytes_following; 67 } AVB_ATTR_PACKED AvbDescriptor; 68 69 /* Copies |src| to |dest| and validates, byte-swapping fields in the 70 * process if needed. Returns true if valid, false if invalid. 71 * 72 * Data following the struct is not validated nor copied. 73 */ 74 bool avb_descriptor_validate_and_byteswap( 75 const AvbDescriptor* src, AvbDescriptor* dest) AVB_ATTR_WARN_UNUSED_RESULT; 76 77 /* Signature for callback function used in avb_descriptor_foreach(). 78 * The passed in descriptor is given by |descriptor| and the 79 * |user_data| passed to avb_descriptor_foreach() function is in 80 * |user_data|. Return true to continue iterating, false to stop 81 * iterating. 82 * 83 * Note that |descriptor| points into the image passed to 84 * avb_descriptor_foreach() - all fields need to be byteswapped! 85 */ 86 typedef bool AvbDescriptorForeachFunc(const AvbDescriptor* descriptor, 87 void* user_data); 88 89 /* Convenience function to iterate over all descriptors in an vbmeta 90 * image. 91 * 92 * The function given by |foreach_func| will be called for each 93 * descriptor. The given function should return true to continue 94 * iterating, false to stop. 95 * 96 * The |user_data| parameter will be passed to |foreach_func|. 97 * 98 * Returns false if the iteration was short-circuited, that is if 99 * an invocation of |foreach_func| returned false. 100 * 101 * Before using this function, you MUST verify |image_data| with 102 * avb_vbmeta_image_verify() and reject it unless it's signed by a known 103 * good public key. Additionally, |image_data| must be word-aligned. 104 */ 105 bool avb_descriptor_foreach(const uint8_t* image_data, 106 size_t image_size, 107 AvbDescriptorForeachFunc foreach_func, 108 void* user_data); 109 110 /* Gets all descriptors in a vbmeta image. 111 * 112 * The return value is a NULL-pointer terminated array of 113 * AvbDescriptor pointers. Free with avb_free() when you are done with 114 * it. If |out_num_descriptors| is non-NULL, the number of descriptors 115 * will be returned there. 116 * 117 * Note that each AvbDescriptor pointer in the array points into 118 * |image_data| - all fields need to be byteswapped! 119 * 120 * Before using this function, you MUST verify |image_data| with 121 * avb_vbmeta_image_verify() and reject it unless it's signed by a known 122 * good public key. Additionally, |image_data| must be word-aligned. 123 */ 124 const AvbDescriptor** avb_descriptor_get_all(const uint8_t* image_data, 125 size_t image_size, 126 size_t* out_num_descriptors) 127 AVB_ATTR_WARN_UNUSED_RESULT; 128 129 #ifdef __cplusplus 130 } 131 #endif 132 133 #endif /* AVB_DESCRIPTOR_H_ */ 134