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_PROPERTY_DESCRIPTOR_H_ 30 #define AVB_PROPERTY_DESCRIPTOR_H_ 31 32 #include "avb_descriptor.h" 33 34 #ifdef __cplusplus 35 extern "C" { 36 #endif 37 38 /* A descriptor for properties (free-form key/value pairs). 39 * 40 * Following this struct are |key_num_bytes| bytes of key data, 41 * followed by a NUL byte, then |value_num_bytes| bytes of value data, 42 * followed by a NUL byte and then enough padding to make the combined 43 * size a multiple of 8. 44 */ 45 typedef struct AvbPropertyDescriptor { 46 AvbDescriptor parent_descriptor; 47 uint64_t key_num_bytes; 48 uint64_t value_num_bytes; 49 } AVB_ATTR_PACKED AvbPropertyDescriptor; 50 51 /* Copies |src| to |dest| and validates, byte-swapping fields in the 52 * process if needed. Returns true if valid, false if invalid. 53 * 54 * Data following the struct is not validated nor copied. 55 */ 56 bool avb_property_descriptor_validate_and_byteswap( 57 const AvbPropertyDescriptor* src, 58 AvbPropertyDescriptor* dest) AVB_ATTR_WARN_UNUSED_RESULT; 59 60 /* Convenience function for looking up the value for a property with 61 * name |key| in a vbmeta image. If |key_size| is 0, |key| must be 62 * NUL-terminated. 63 * 64 * The |image_data| parameter must be a pointer to a vbmeta image of 65 * size |image_size|. 66 * 67 * This function returns a pointer to the value inside the passed-in 68 * image or NULL if not found. Note that the value is always 69 * guaranteed to be followed by a NUL byte. 70 * 71 * If the value was found and |out_value_size| is not NULL, the size 72 * of the value is returned there. 73 * 74 * This function is O(n) in number of descriptors so if you need to 75 * look up a lot of values, you may want to build a more efficient 76 * lookup-table by manually walking all descriptors using 77 * avb_descriptor_foreach(). 78 * 79 * Before using this function, you MUST verify |image_data| with 80 * avb_vbmeta_image_verify() and reject it unless it's signed by a 81 * known good public key. 82 */ 83 const char* avb_property_lookup(const uint8_t* image_data, 84 size_t image_size, 85 const char* key, 86 size_t key_size, 87 size_t* out_value_size) 88 AVB_ATTR_WARN_UNUSED_RESULT; 89 90 /* Like avb_property_lookup() but parses the intial portions of the 91 * value as an unsigned 64-bit integer. Both decimal and hexadecimal 92 * representations (e.g. "0x2a") are supported. Returns false on 93 * failure and true on success. On success, the parsed value is 94 * returned in |out_value|. 95 */ 96 bool avb_property_lookup_uint64(const uint8_t* image_data, 97 size_t image_size, 98 const char* key, 99 size_t key_size, 100 uint64_t* out_value) 101 AVB_ATTR_WARN_UNUSED_RESULT; 102 103 #ifdef __cplusplus 104 } 105 #endif 106 107 #endif /* AVB_PROPERTY_DESCRIPTOR_H_ */ 108