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 AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT 55 } AvbSlotVerifyResult; 56 57 /* Various error handling modes for when verification fails using a 58 * hashtree at runtime inside the HLOS. 59 * 60 * AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE means that the OS 61 * will invalidate the current slot and restart. 62 * 63 * AVB_HASHTREE_ERROR_MODE_RESTART means that the OS will restart. 64 * 65 * AVB_HASHTREE_ERROR_MODE_EIO means that an EIO error will be 66 * returned to applications. 67 * 68 * AVB_HASHTREE_ERROR_MODE_LOGGING means that errors will be logged 69 * and corrupt data may be returned to applications. This mode should 70 * be used ONLY for diagnostics and debugging. It cannot be used 71 * unless AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR is also 72 * used. 73 */ 74 typedef enum { 75 AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE, 76 AVB_HASHTREE_ERROR_MODE_RESTART, 77 AVB_HASHTREE_ERROR_MODE_EIO, 78 AVB_HASHTREE_ERROR_MODE_LOGGING 79 } AvbHashtreeErrorMode; 80 81 /* Flags that influence how avb_slot_verify() works. 82 * 83 * If AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR is NOT set then 84 * avb_slot_verify() will bail out as soon as an error is encountered 85 * and |out_data| is set only if AVB_SLOT_VERIFY_RESULT_OK is 86 * returned. 87 * 88 * Otherwise if AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR is set 89 * avb_slot_verify() will continue verification efforts and |out_data| 90 * is also set if AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED, 91 * AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION, or 92 * AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX is returned. It is 93 * undefined which error is returned if more than one distinct error 94 * is encountered. It is guaranteed that AVB_SLOT_VERIFY_RESULT_OK is 95 * returned if, and only if, there are no errors. This mode is needed 96 * to boot valid but unverified slots when the device is unlocked. 97 * 98 * Also, if AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR is set the 99 * contents loaded from |requested_partition| will be the contents of 100 * the entire partition instead of just the size specified in the hash 101 * descriptor. 102 */ 103 typedef enum { 104 AVB_SLOT_VERIFY_FLAGS_NONE = 0, 105 AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR = (1 << 0) 106 } AvbSlotVerifyFlags; 107 108 /* Get a textual representation of |result|. */ 109 const char* avb_slot_verify_result_to_string(AvbSlotVerifyResult result); 110 111 /* Maximum number of rollback index locations supported. */ 112 #define AVB_MAX_NUMBER_OF_ROLLBACK_INDEX_LOCATIONS 32 113 114 /* AvbPartitionData contains data loaded from partitions when using 115 * avb_slot_verify(). The |partition_name| field contains the name of 116 * the partition (without A/B suffix), |data| points to the loaded 117 * data which is |data_size| bytes long. If |preloaded| is set to true, 118 * this structure dose not own |data|. The caller of |avb_slot_verify| 119 * needs to make sure that the preloaded data outlives this 120 * |AvbPartitionData| structure. 121 * 122 * Note that this is strictly less than the partition size - it's only 123 * the image stored there, not the entire partition nor any of the 124 * metadata. 125 */ 126 typedef struct { 127 char* partition_name; 128 uint8_t* data; 129 size_t data_size; 130 bool preloaded; 131 } AvbPartitionData; 132 133 /* AvbVBMetaData contains a vbmeta struct loaded from a partition when 134 * using avb_slot_verify(). The |partition_name| field contains the 135 * name of the partition (without A/B suffix), |vbmeta_data| points to 136 * the loaded data which is |vbmeta_size| bytes long. 137 * 138 * The |verify_result| field contains the result of 139 * avb_vbmeta_image_verify() on the data. This is guaranteed to be 140 * AVB_VBMETA_VERIFY_RESULT_OK for all vbmeta images if 141 * avb_slot_verify() returns AVB_SLOT_VERIFY_RESULT_OK. 142 * 143 * You can use avb_descriptor_get_all(), avb_descriptor_foreach(), and 144 * avb_vbmeta_image_header_to_host_byte_order() with this data. 145 */ 146 typedef struct { 147 char* partition_name; 148 uint8_t* vbmeta_data; 149 size_t vbmeta_size; 150 AvbVBMetaVerifyResult verify_result; 151 } AvbVBMetaData; 152 153 /* AvbSlotVerifyData contains data needed to boot a particular slot 154 * and is returned by avb_slot_verify() if partitions in a slot are 155 * successfully verified. 156 * 157 * All data pointed to by this struct - including data in each item in 158 * the |partitions| array - will be freed when the 159 * avb_slot_verify_data_free() function is called. 160 * 161 * The |ab_suffix| field is the copy of the of |ab_suffix| field 162 * passed to avb_slot_verify(). It is the A/B suffix of the slot. This 163 * value includes the leading underscore - typical values are "" (if 164 * no slots are in use), "_a" (for the first slot), and "_b" (for the 165 * second slot). 166 * 167 * The VBMeta images that were checked are available in the 168 * |vbmeta_images| field. The field |num_vbmeta_images| contains the 169 * number of elements in this array. The first element - 170 * vbmeta_images[0] - is guaranteed to be from the partition with the 171 * top-level vbmeta struct. This is usually the "vbmeta" partition in 172 * the requested slot but if there is no "vbmeta" partition it can 173 * also be the "boot" partition. 174 * 175 * The partitions loaded and verified from from the slot are 176 * accessible in the |loaded_partitions| array. The field 177 * |num_loaded_partitions| contains the number of elements in this 178 * array. The order of partitions in this array may not necessarily be 179 * the same order as in the passed-in |requested_partitions| array. 180 * 181 * Rollback indexes for the verified slot are stored in the 182 * |rollback_indexes| field. Note that avb_slot_verify() will NEVER 183 * modify stored_rollback_index[n] locations e.g. it will never use 184 * the write_rollback_index() AvbOps operation. Instead it is the job 185 * of the caller of avb_slot_verify() to do this based on e.g. A/B 186 * policy and other factors. See libavb_ab/avb_ab_flow.c for an 187 * example of how to do this. 188 * 189 * The |cmdline| field is a NUL-terminated string in UTF-8 resulting 190 * from concatenating all |AvbKernelCmdlineDescriptor| and then 191 * performing proper substitution of the variables 192 * $(ANDROID_SYSTEM_PARTUUID), $(ANDROID_BOOT_PARTUUID), and 193 * $(ANDROID_VBMETA_PARTUUID) using the 194 * get_unique_guid_for_partition() operation in |AvbOps|. Additionally 195 * $(ANDROID_VERITY_MODE) will be replaced with the proper dm-verity 196 * option depending on the value of |hashtree_error_mode|. 197 * 198 * Additionally, the |cmdline| field will have the following kernel 199 * command-line options set (unless verification is disabled, see 200 * below): 201 * 202 * androidboot.veritymode: This is set to 'disabled' if the 203 * AVB_VBMETA_IMAGE_FLAGS_HASHTREE_DISABLED flag is set in top-level 204 * vbmeta struct. Otherwise it is set to 'enforcing' if the 205 * passed-in hashtree error mode is AVB_HASHTREE_ERROR_MODE_RESTART 206 * or AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE, 'eio' if it's 207 * set to AVB_HASHTREE_ERROR_MODE_EIO, and 'logging' if it's set to 208 * AVB_HASHTREE_ERROR_MODE_LOGGING. 209 * 210 * androidboot.vbmeta.invalidate_on_error: This is set to 'yes' only 211 * if hashtree validation isn't disabled and the passed-in hashtree 212 * error mode is AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE. 213 * 214 * androidboot.vbmeta.device_state: set to "locked" or "unlocked" 215 * depending on the result of the result of AvbOps's 216 * read_is_unlocked() function. 217 * 218 * androidboot.vbmeta.{hash_alg, size, digest}: Will be set to 219 * the digest of all images in |vbmeta_images|. 220 * 221 * androidboot.vbmeta.device: This is set to the value 222 * PARTUUID=$(ANDROID_VBMETA_PARTUUID) before substitution so it 223 * will end up pointing to the vbmeta partition for the verified 224 * slot. If there is no vbmeta partition it will point to the boot 225 * partition of the verified slot. 226 * 227 * androidboot.vbmeta.avb_version: This is set to the decimal value 228 * of AVB_VERSION_MAJOR followed by a dot followed by the decimal 229 * value of AVB_VERSION_MINOR, for example "1.0" or "1.4". This 230 * version number represents the vbmeta file format version 231 * supported by libavb copy used in the boot loader. This is not 232 * necessarily the same version number of the on-disk metadata for 233 * the slot that was verified. 234 * 235 * Note that androidboot.slot_suffix is not set in the |cmdline| field 236 * in |AvbSlotVerifyData| - you will have to set this yourself. 237 * 238 * If the |AVB_VBMETA_IMAGE_FLAGS_VERIFICATION_DISABLED| flag is set 239 * in the top-level vbmeta struct then only the top-level vbmeta 240 * struct is verified and descriptors will not processed. The return 241 * value will be set accordingly (if this flag is set via 'avbctl 242 * disable-verification' then the return value will be 243 * |AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION|) and 244 * |AvbSlotVerifyData| is returned. Additionally all partitions in the 245 * |requested_partitions| are loaded and the |cmdline| field is set to 246 * "root=PARTUUID=$(ANDROID_SYSTEM_PARTUUID)" and the GUID for the 247 * appropriate system partition is substituted in. Note that none of 248 * the androidboot.* options mentioned above will be set. 249 * 250 * This struct may grow in the future without it being considered an 251 * ABI break. 252 */ 253 typedef struct { 254 char* ab_suffix; 255 AvbVBMetaData* vbmeta_images; 256 size_t num_vbmeta_images; 257 AvbPartitionData* loaded_partitions; 258 size_t num_loaded_partitions; 259 char* cmdline; 260 uint64_t rollback_indexes[AVB_MAX_NUMBER_OF_ROLLBACK_INDEX_LOCATIONS]; 261 } AvbSlotVerifyData; 262 263 /* Frees a |AvbSlotVerifyData| including all data it points to. */ 264 void avb_slot_verify_data_free(AvbSlotVerifyData* data); 265 266 /* Performs a full verification of the slot identified by |ab_suffix| 267 * and load and verify the contents of the partitions whose name is in 268 * the NULL-terminated string array |requested_partitions| (each 269 * partition must use hash verification). If not using A/B, pass an 270 * empty string (e.g. "", not NULL) for |ab_suffix|. This parameter 271 * must include the leading underscore, for example "_a" should be 272 * used to refer to the first slot. 273 * 274 * Typically the |requested_partitions| array only contains a single 275 * item for the boot partition, 'boot'. 276 * 277 * Verification includes loading and verifying data from the 'vbmeta', 278 * the requested hash partitions, and possibly other partitions (with 279 * |ab_suffix| appended), inspecting rollback indexes, and checking if 280 * the public key used to sign the data is acceptable. The functions 281 * in |ops| will be used to do this. 282 * 283 * If |out_data| is not NULL, it will be set to a newly allocated 284 * |AvbSlotVerifyData| struct containing all the data needed to 285 * actually boot the slot. This data structure should be freed with 286 * avb_slot_verify_data_free() when you are done with it. See below 287 * for when this is returned. 288 * 289 * The |flags| parameter is used to influence the semantics of 290 * avb_slot_verify() - for example the 291 * AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR flag can be used to 292 * ignore verification errors which is something needed in the 293 * UNLOCKED state. See the AvbSlotVerifyFlags enumeration for details. 294 * 295 * The |hashtree_error_mode| parameter should be set to the desired 296 * error handling mode when hashtree validation fails inside the 297 * HLOS. This value isn't used by libavb per se - it is forwarded to 298 * the HLOS through the androidboot.veritymode and 299 * androidboot.vbmeta.invalidate_on_error cmdline parameters. See the 300 * AvbHashtreeErrorMode enumeration for details. 301 * 302 * Also note that |out_data| is never set if 303 * AVB_SLOT_VERIFY_RESULT_ERROR_OOM, AVB_SLOT_VERIFY_RESULT_ERROR_IO, 304 * or AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA is returned. 305 * 306 * AVB_SLOT_VERIFY_RESULT_OK is returned if everything is verified 307 * correctly and all public keys are accepted. 308 * 309 * AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED is returned if 310 * everything is verified correctly out but one or more public keys 311 * are not accepted. This includes the case where integrity data is 312 * not signed. 313 * 314 * AVB_SLOT_VERIFY_RESULT_ERROR_OOM is returned if unable to 315 * allocate memory. 316 * 317 * AVB_SLOT_VERIFY_RESULT_ERROR_IO is returned if an I/O error 318 * occurred while trying to load data or get a rollback index. 319 * 320 * AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION is returned if the data 321 * did not verify, e.g. the digest didn't match or signature checks 322 * failed. 323 * 324 * AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX is returned if a 325 * rollback index was less than its stored value. 326 * 327 * AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA is returned if some 328 * of the metadata is invalid or inconsistent. 329 * 330 * AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION is returned if 331 * some of the metadata requires a newer version of libavb than what 332 * is in use. 333 * 334 * AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT is returned if the 335 * caller passed invalid parameters, for example trying to use 336 * AVB_HASHTREE_ERROR_MODE_LOGGING without 337 * AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR. 338 */ 339 AvbSlotVerifyResult avb_slot_verify(AvbOps* ops, 340 const char* const* requested_partitions, 341 const char* ab_suffix, 342 AvbSlotVerifyFlags flags, 343 AvbHashtreeErrorMode hashtree_error_mode, 344 AvbSlotVerifyData** out_data); 345 346 #ifdef __cplusplus 347 } 348 #endif 349 350 #endif /* AVB_SLOT_VERIFY_H_ */ 351
