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_SLOT_VERIFY_H_ 30 #define AVB_SLOT_VERIFY_H_ 31 32 #include "avb_ops.h" 33 #include "avb_vbmeta_image.h" 34 35 #ifdef __cplusplus 36 extern "C" { 37 #endif 38 39 /* Return codes used in avb_slot_verify(), see that function for 40 * documentation for each field. 41 * 42 * Use avb_slot_verify_result_to_string() to get a textual 43 * representation usable for error/debug output. 44 */ 45 typedef enum { 46 AVB_SLOT_VERIFY_RESULT_OK, 47 AVB_SLOT_VERIFY_RESULT_ERROR_OOM, 48 AVB_SLOT_VERIFY_RESULT_ERROR_IO, 49 AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION, 50 AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX, 51 AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED, 52 AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA, 53 AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION 54 } AvbSlotVerifyResult; 55 56 /* Get a textual representation of |result|. */ 57 const char* avb_slot_verify_result_to_string(AvbSlotVerifyResult result); 58 59 /* Maximum number of rollback index locations supported. */ 60 #define AVB_MAX_NUMBER_OF_ROLLBACK_INDEX_LOCATIONS 32 61 62 /* AvbPartitionData contains data loaded from partitions when using 63 * avb_slot_verify(). The |partition_name| field contains the name of 64 * the partition (without A/B suffix), |data| points to the loaded 65 * data which is |data_size| bytes long. 66 * 67 * Note that this is strictly less than the partition size - it's only 68 * the image stored there, not the entire partition nor any of the 69 * metadata. 70 */ 71 typedef struct { 72 char* partition_name; 73 uint8_t* data; 74 size_t data_size; 75 } AvbPartitionData; 76 77 /* AvbVBMetaData contains a vbmeta struct loaded from a partition when 78 * using avb_slot_verify(). The |partition_name| field contains the 79 * name of the partition (without A/B suffix), |vbmeta_data| points to 80 * the loaded data which is |vbmeta_size| bytes long. 81 * 82 * The |verify_result| field contains the result of 83 * avb_vbmeta_image_verify() on the data. This is guaranteed to be 84 * AVB_VBMETA_VERIFY_RESULT_OK for all vbmeta images if 85 * avb_slot_verify() returns AVB_SLOT_VERIFY_RESULT_OK. 86 * 87 * You can use avb_descriptor_get_all(), avb_descriptor_foreach(), and 88 * avb_vbmeta_image_header_to_host_byte_order() with this data. 89 */ 90 typedef struct { 91 char* partition_name; 92 uint8_t* vbmeta_data; 93 size_t vbmeta_size; 94 AvbVBMetaVerifyResult verify_result; 95 } AvbVBMetaData; 96 97 /* AvbSlotVerifyData contains data needed to boot a particular slot 98 * and is returned by avb_slot_verify() if partitions in a slot are 99 * successfully verified. 100 * 101 * All data pointed to by this struct - including data in each item in 102 * the |partitions| array - will be freed when the 103 * avb_slot_verify_data_free() function is called. 104 * 105 * The |ab_suffix| field is the copy of the of |ab_suffix| field 106 * passed to avb_slot_verify(). It is the A/B suffix of the slot. 107 * 108 * The VBMeta images that were checked are available in the 109 * |vbmeta_images| field. The field |num_vbmeta_images| contains the 110 * number of elements in this array. The first element - 111 * vbmeta_images[0] - is guaranteed to be from the partition with the 112 * top-level vbmeta struct. This is usually the "vbmeta" partition in 113 * the requested slot but if there is no "vbmeta" partition it can 114 * also be the "boot" partition. 115 * 116 * The partitions loaded and verified from from the slot are 117 * accessible in the |loaded_partitions| array. The field 118 * |num_loaded_partitions| contains the number of elements in this 119 * array. The order of partitions in this array may not necessarily be 120 * the same order as in the passed-in |requested_partitions| array. 121 * 122 * Rollback indexes for the verified slot are stored in the 123 * |rollback_indexes| field. Note that avb_slot_verify() will NEVER 124 * modify stored_rollback_index[n] locations e.g. it will never use 125 * the write_rollback_index() AvbOps operation. Instead it is the job 126 * of the caller of avb_slot_verify() to do this based on e.g. A/B 127 * policy and other factors. See libavb_ab/avb_ab_flow.c for an 128 * example of how to do this. 129 * 130 * The |cmdline| field is a NUL-terminated string in UTF-8 resulting 131 * from concatenating all |AvbKernelCmdlineDescriptor| and then 132 * performing proper substitution of the variables 133 * $(ANDROID_SYSTEM_PARTUUID), $(ANDROID_BOOT_PARTUUID), and 134 * $(ANDROID_VBMETA_PARTUUID) using the 135 * get_unique_guid_for_partition() operation in |AvbOps|. 136 * 137 * Additionally, the |cmdline| field will have the following kernel 138 * command-line options set: 139 * 140 * androidboot.vbmeta.device_state: set to "locked" or "unlocked" 141 * depending on the result of the result of AvbOps's 142 * read_is_unlocked() function. 143 * 144 * androidboot.vbmeta.{hash_alg, size, digest}: Will be set to 145 * the digest of all images in |vbmeta_images|. 146 * 147 * androidboot.vbmeta.device: This is set to the value 148 * PARTUUID=$(ANDROID_VBMETA_PARTUUID) before substitution so it 149 * will end up pointing to the vbmeta partition for the verified 150 * slot. If there is no vbmeta partition it will point to the boot 151 * partition of the verified slot. 152 * 153 * androidboot.vbmeta.avb_version: This is set to the decimal value 154 * of AVB_VERSION_MAJOR followed by a dot followed by the decimal 155 * value of AVB_VERSION_MINOR, for example "1.0" or "1.4". This 156 * version number represents the vbmeta file format version 157 * supported by libavb copy used in the boot loader. This is not 158 * necessarily the same version number of the on-disk metadata for 159 * the slot that was verified. 160 * 161 * Note that androidboot.slot_suffix is not set in |cmdline| - you 162 * will have to pass this command-line option yourself. 163 * 164 * This struct may grow in the future without it being considered an 165 * ABI break. 166 */ 167 typedef struct { 168 char* ab_suffix; 169 AvbVBMetaData* vbmeta_images; 170 size_t num_vbmeta_images; 171 AvbPartitionData* loaded_partitions; 172 size_t num_loaded_partitions; 173 char* cmdline; 174 uint64_t rollback_indexes[AVB_MAX_NUMBER_OF_ROLLBACK_INDEX_LOCATIONS]; 175 } AvbSlotVerifyData; 176 177 /* Frees a |AvbSlotVerifyData| including all data it points to. */ 178 void avb_slot_verify_data_free(AvbSlotVerifyData* data); 179 180 /* Performs a full verification of the slot identified by |ab_suffix| 181 * and load the contents of the partitions whose name is in the 182 * NULL-terminated string array |requested_partitions| (each partition 183 * must use hash verification). If not using A/B, pass an empty string 184 * (e.g. "", not NULL) for |ab_suffix|. 185 * 186 * Typically the |requested_partitions| array only contains a single 187 * item for the boot partition, 'boot'. 188 * 189 * Verification includes loading data from the 'vbmeta', all hash 190 * partitions, and possibly other partitions (with |ab_suffix| 191 * appended), inspecting rollback indexes, and checking if the public 192 * key used to sign the data is acceptable. The functions in |ops| 193 * will be used to do this. 194 * 195 * If |out_data| is not NULL, it will be set to a newly allocated 196 * |AvbSlotVerifyData| struct containing all the data needed to 197 * actually boot the slot. This data structure should be freed with 198 * avb_slot_verify_data_free() when you are done with it. See below 199 * for when this is returned. 200 * 201 * If |allow_verification_error| is false this function will bail out 202 * as soon as an error is encountered and |out_data| is set only if 203 * AVB_SLOT_VERIFY_RESULT_OK is returned. 204 * 205 * Otherwise if |allow_verification_error| is true the function will 206 * continue verification efforts and |out_data| is also set if 207 * AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED, 208 * AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION, or 209 * AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX is returned. It is 210 * undefined which error is returned if more than one distinct error 211 * is encountered. It is guaranteed that AVB_SLOT_VERIFY_RESULT_OK is 212 * returned if, and only if, there are no errors. This mode is needed 213 * to boot valid but unverified slots when the device is unlocked. 214 * 215 * Also note that |out_data| is never set if 216 * AVB_SLOT_VERIFY_RESULT_ERROR_OOM, AVB_SLOT_VERIFY_RESULT_ERROR_IO, 217 * or AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA is returned. 218 * 219 * AVB_SLOT_VERIFY_RESULT_OK is returned if everything is verified 220 * correctly and all public keys are accepted. 221 * 222 * AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED is returned if 223 * everything is verified correctly out but one or more public keys 224 * are not accepted. This includes the case where integrity data is 225 * not signed. 226 * 227 * AVB_SLOT_VERIFY_RESULT_ERROR_OOM is returned if unable to 228 * allocate memory. 229 * 230 * AVB_SLOT_VERIFY_RESULT_ERROR_IO is returned if an I/O error 231 * occurred while trying to load data or get a rollback index. 232 * 233 * AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION is returned if the data 234 * did not verify, e.g. the digest didn't match or signature checks 235 * failed. 236 * 237 * AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX is returned if a 238 * rollback index was less than its stored value. 239 * 240 * AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA is returned if some 241 * of the metadata is invalid or inconsistent. 242 * 243 * AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION is returned if 244 * some of the metadata requires a newer version of libavb than what 245 * is in use. 246 */ 247 AvbSlotVerifyResult avb_slot_verify(AvbOps* ops, 248 const char* const* requested_partitions, 249 const char* ab_suffix, 250 bool allow_verification_error, 251 AvbSlotVerifyData** out_data); 252 253 #ifdef __cplusplus 254 } 255 #endif 256 257 #endif /* AVB_SLOT_VERIFY_H_ */ 258
