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_PROPERTY_DESCRIPTOR_H_ 32 #define AVB_PROPERTY_DESCRIPTOR_H_ 33 34 #include <android_avb/avb_descriptor.h> 35 36 #ifdef __cplusplus 37 extern "C" { 38 #endif 39 40 /* A descriptor for properties (free-form key/value pairs). 41 * 42 * Following this struct are |key_num_bytes| bytes of key data, 43 * followed by a NUL byte, then |value_num_bytes| bytes of value data, 44 * followed by a NUL byte and then enough padding to make the combined 45 * size a multiple of 8. 46 */ 47 typedef struct AvbPropertyDescriptor { 48 AvbDescriptor parent_descriptor; 49 uint64_t key_num_bytes; 50 uint64_t value_num_bytes; 51 } AVB_ATTR_PACKED AvbPropertyDescriptor; 52 53 /* Copies |src| to |dest| and validates, byte-swapping fields in the 54 * process if needed. Returns true if valid, false if invalid. 55 * 56 * Data following the struct is not validated nor copied. 57 */ 58 bool avb_property_descriptor_validate_and_byteswap( 59 const AvbPropertyDescriptor* src, 60 AvbPropertyDescriptor* dest) AVB_ATTR_WARN_UNUSED_RESULT; 61 62 /* Convenience function for looking up the value for a property with 63 * name |key| in a vbmeta image. If |key_size| is 0, |key| must be 64 * NUL-terminated. 65 * 66 * The |image_data| parameter must be a pointer to a vbmeta image of 67 * size |image_size|. 68 * 69 * This function returns a pointer to the value inside the passed-in 70 * image or NULL if not found. Note that the value is always 71 * guaranteed to be followed by a NUL byte. 72 * 73 * If the value was found and |out_value_size| is not NULL, the size 74 * of the value is returned there. 75 * 76 * This function is O(n) in number of descriptors so if you need to 77 * look up a lot of values, you may want to build a more efficient 78 * lookup-table by manually walking all descriptors using 79 * avb_descriptor_foreach(). 80 * 81 * Before using this function, you MUST verify |image_data| with 82 * avb_vbmeta_image_verify() and reject it unless it's signed by a 83 * known good public key. 84 */ 85 const char* avb_property_lookup(const uint8_t* image_data, 86 size_t image_size, 87 const char* key, 88 size_t key_size, 89 size_t* out_value_size) 90 AVB_ATTR_WARN_UNUSED_RESULT; 91 92 /* Like avb_property_lookup() but parses the intial portions of the 93 * value as an unsigned 64-bit integer. Both decimal and hexadecimal 94 * representations (e.g. "0x2a") are supported. Returns false on 95 * failure and true on success. On success, the parsed value is 96 * returned in |out_value|. 97 */ 98 bool avb_property_lookup_uint64(const uint8_t* image_data, 99 size_t image_size, 100 const char* key, 101 size_t key_size, 102 uint64_t* out_value) 103 AVB_ATTR_WARN_UNUSED_RESULT; 104 105 #ifdef __cplusplus 106 } 107 #endif 108 109 #endif /* AVB_PROPERTY_DESCRIPTOR_H_ */ 110