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_SLOT_VERIFY_H_ 32 #define AVB_SLOT_VERIFY_H_ 33 34 #include <android_avb/avb_ops.h> 35 #include <android_avb/avb_vbmeta_image.h> 36 37 #ifdef __cplusplus 38 extern "C" { 39 #endif 40 41 /* Return codes used in avb_slot_verify(), see that function for 42 * documentation for each field. 43 * 44 * Use avb_slot_verify_result_to_string() to get a textual 45 * representation usable for error/debug output. 46 */ 47 typedef enum { 48 AVB_SLOT_VERIFY_RESULT_OK, 49 AVB_SLOT_VERIFY_RESULT_ERROR_OOM, 50 AVB_SLOT_VERIFY_RESULT_ERROR_IO, 51 AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION, 52 AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX, 53 AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED, 54 AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA, 55 AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION, 56 AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT 57 } AvbSlotVerifyResult; 58 59 /* Various error handling modes for when verification fails using a 60 * hashtree at runtime inside the HLOS. 61 * 62 * AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE means that the OS 63 * will invalidate the current slot and restart. 64 * 65 * AVB_HASHTREE_ERROR_MODE_RESTART means that the OS will restart. 66 * 67 * AVB_HASHTREE_ERROR_MODE_EIO means that an EIO error will be 68 * returned to applications. 69 * 70 * AVB_HASHTREE_ERROR_MODE_LOGGING means that errors will be logged 71 * and corrupt data may be returned to applications. This mode should 72 * be used ONLY for diagnostics and debugging. It cannot be used 73 * unless AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR is also 74 * used. 75 */ 76 typedef enum { 77 AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE, 78 AVB_HASHTREE_ERROR_MODE_RESTART, 79 AVB_HASHTREE_ERROR_MODE_EIO, 80 AVB_HASHTREE_ERROR_MODE_LOGGING 81 } AvbHashtreeErrorMode; 82 83 /* Flags that influence how avb_slot_verify() works. 84 * 85 * If AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR is NOT set then 86 * avb_slot_verify() will bail out as soon as an error is encountered 87 * and |out_data| is set only if AVB_SLOT_VERIFY_RESULT_OK is 88 * returned. 89 * 90 * Otherwise if AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR is set 91 * avb_slot_verify() will continue verification efforts and |out_data| 92 * is also set if AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED, 93 * AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION, or 94 * AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX is returned. It is 95 * undefined which error is returned if more than one distinct error 96 * is encountered. It is guaranteed that AVB_SLOT_VERIFY_RESULT_OK is 97 * returned if, and only if, there are no errors. This mode is needed 98 * to boot valid but unverified slots when the device is unlocked. 99 * 100 * Also, if AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR is set the 101 * contents loaded from |requested_partition| will be the contents of 102 * the entire partition instead of just the size specified in the hash 103 * descriptor. 104 */ 105 typedef enum { 106 AVB_SLOT_VERIFY_FLAGS_NONE = 0, 107 AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR = (1 << 0) 108 } AvbSlotVerifyFlags; 109 110 /* Get a textual representation of |result|. */ 111 const char* avb_slot_verify_result_to_string(AvbSlotVerifyResult result); 112 113 /* Maximum number of rollback index locations supported. */ 114 #define AVB_MAX_NUMBER_OF_ROLLBACK_INDEX_LOCATIONS 32 115 116 /* AvbPartitionData contains data loaded from partitions when using 117 * avb_slot_verify(). The |partition_name| field contains the name of 118 * the partition (without A/B suffix), |data| points to the loaded 119 * data which is |data_size| bytes long. If |preloaded| is set to true, 120 * this structure dose not own |data|. The caller of |avb_slot_verify| 121 * needs to make sure that the preloaded data outlives this 122 * |AvbPartitionData| structure. 123 * 124 * Note that this is strictly less than the partition size - it's only 125 * the image stored there, not the entire partition nor any of the 126 * metadata. 127 */ 128 typedef struct { 129 char* partition_name; 130 uint8_t* data; 131 size_t data_size; 132 bool preloaded; 133 } AvbPartitionData; 134 135 /* AvbVBMetaData contains a vbmeta struct loaded from a partition when 136 * using avb_slot_verify(). The |partition_name| field contains the 137 * name of the partition (without A/B suffix), |vbmeta_data| points to 138 * the loaded data which is |vbmeta_size| bytes long. 139 * 140 * The |verify_result| field contains the result of 141 * avb_vbmeta_image_verify() on the data. This is guaranteed to be 142 * AVB_VBMETA_VERIFY_RESULT_OK for all vbmeta images if 143 * avb_slot_verify() returns AVB_SLOT_VERIFY_RESULT_OK. 144 * 145 * You can use avb_descriptor_get_all(), avb_descriptor_foreach(), and 146 * avb_vbmeta_image_header_to_host_byte_order() with this data. 147 */ 148 typedef struct { 149 char* partition_name; 150 uint8_t* vbmeta_data; 151 size_t vbmeta_size; 152 AvbVBMetaVerifyResult verify_result; 153 } AvbVBMetaData; 154 155 /* AvbSlotVerifyData contains data needed to boot a particular slot 156 * and is returned by avb_slot_verify() if partitions in a slot are 157 * successfully verified. 158 * 159 * All data pointed to by this struct - including data in each item in 160 * the |partitions| array - will be freed when the 161 * avb_slot_verify_data_free() function is called. 162 * 163 * The |ab_suffix| field is the copy of the of |ab_suffix| field 164 * passed to avb_slot_verify(). It is the A/B suffix of the slot. This 165 * value includes the leading underscore - typical values are "" (if 166 * no slots are in use), "_a" (for the first slot), and "_b" (for the 167 * second slot). 168 * 169 * The VBMeta images that were checked are available in the 170 * |vbmeta_images| field. The field |num_vbmeta_images| contains the 171 * number of elements in this array. The first element - 172 * vbmeta_images[0] - is guaranteed to be from the partition with the 173 * top-level vbmeta struct. This is usually the "vbmeta" partition in 174 * the requested slot but if there is no "vbmeta" partition it can 175 * also be the "boot" partition. 176 * 177 * The partitions loaded and verified from from the slot are 178 * accessible in the |loaded_partitions| array. The field 179 * |num_loaded_partitions| contains the number of elements in this 180 * array. The order of partitions in this array may not necessarily be 181 * the same order as in the passed-in |requested_partitions| array. 182 * 183 * Rollback indexes for the verified slot are stored in the 184 * |rollback_indexes| field. Note that avb_slot_verify() will NEVER 185 * modify stored_rollback_index[n] locations e.g. it will never use 186 * the write_rollback_index() AvbOps operation. Instead it is the job 187 * of the caller of avb_slot_verify() to do this based on e.g. A/B 188 * policy and other factors. See libavb_ab/avb_ab_flow.c for an 189 * example of how to do this. 190 * 191 * The |cmdline| field is a NUL-terminated string in UTF-8 resulting 192 * from concatenating all |AvbKernelCmdlineDescriptor| and then 193 * performing proper substitution of the variables 194 * $(ANDROID_SYSTEM_PARTUUID), $(ANDROID_BOOT_PARTUUID), and 195 * $(ANDROID_VBMETA_PARTUUID) using the 196 * get_unique_guid_for_partition() operation in |AvbOps|. Additionally 197 * $(ANDROID_VERITY_MODE) will be replaced with the proper dm-verity 198 * option depending on the value of |hashtree_error_mode|. 199 * 200 * Additionally, the |cmdline| field will have the following kernel 201 * command-line options set (unless verification is disabled, see 202 * below): 203 * 204 * androidboot.veritymode: This is set to 'disabled' if the 205 * AVB_VBMETA_IMAGE_FLAGS_HASHTREE_DISABLED flag is set in top-level 206 * vbmeta struct. Otherwise it is set to 'enforcing' if the 207 * passed-in hashtree error mode is AVB_HASHTREE_ERROR_MODE_RESTART 208 * or AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE, 'eio' if it's 209 * set to AVB_HASHTREE_ERROR_MODE_EIO, and 'logging' if it's set to 210 * AVB_HASHTREE_ERROR_MODE_LOGGING. 211 * 212 * androidboot.vbmeta.invalidate_on_error: This is set to 'yes' only 213 * if hashtree validation isn't disabled and the passed-in hashtree 214 * error mode is AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE. 215 * 216 * androidboot.vbmeta.device_state: set to "locked" or "unlocked" 217 * depending on the result of the result of AvbOps's 218 * read_is_unlocked() function. 219 * 220 * androidboot.vbmeta.{hash_alg, size, digest}: Will be set to 221 * the digest of all images in |vbmeta_images|. 222 * 223 * androidboot.vbmeta.device: This is set to the value 224 * PARTUUID=$(ANDROID_VBMETA_PARTUUID) before substitution so it 225 * will end up pointing to the vbmeta partition for the verified 226 * slot. If there is no vbmeta partition it will point to the boot 227 * partition of the verified slot. 228 * 229 * androidboot.vbmeta.avb_version: This is set to the decimal value 230 * of AVB_VERSION_MAJOR followed by a dot followed by the decimal 231 * value of AVB_VERSION_MINOR, for example "1.0" or "1.4". This 232 * version number represents the vbmeta file format version 233 * supported by libavb copy used in the boot loader. This is not 234 * necessarily the same version number of the on-disk metadata for 235 * the slot that was verified. 236 * 237 * Note that androidboot.slot_suffix is not set in the |cmdline| field 238 * in |AvbSlotVerifyData| - you will have to set this yourself. 239 * 240 * If the |AVB_VBMETA_IMAGE_FLAGS_VERIFICATION_DISABLED| flag is set 241 * in the top-level vbmeta struct then only the top-level vbmeta 242 * struct is verified and descriptors will not processed. The return 243 * value will be set accordingly (if this flag is set via 'avbctl 244 * disable-verification' then the return value will be 245 * |AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION|) and 246 * |AvbSlotVerifyData| is returned. Additionally all partitions in the 247 * |requested_partitions| are loaded and the |cmdline| field is set to 248 * "root=PARTUUID=$(ANDROID_SYSTEM_PARTUUID)" and the GUID for the 249 * appropriate system partition is substituted in. Note that none of 250 * the androidboot.* options mentioned above will be set. 251 * 252 * This struct may grow in the future without it being considered an 253 * ABI break. 254 */ 255 typedef struct { 256 char* ab_suffix; 257 AvbVBMetaData* vbmeta_images; 258 size_t num_vbmeta_images; 259 AvbPartitionData* loaded_partitions; 260 size_t num_loaded_partitions; 261 char* cmdline; 262 uint64_t rollback_indexes[AVB_MAX_NUMBER_OF_ROLLBACK_INDEX_LOCATIONS]; 263 } AvbSlotVerifyData; 264 265 /* Calculates a digest of all vbmeta images in |data| using 266 * the digest indicated by |digest_type|. Stores the result 267 * in |out_digest| which must be large enough to hold a digest 268 * of the requested type. 269 */ 270 void avb_slot_verify_data_calculate_vbmeta_digest(AvbSlotVerifyData* data, 271 AvbDigestType digest_type, 272 uint8_t* out_digest); 273 274 /* Frees a |AvbSlotVerifyData| including all data it points to. */ 275 void avb_slot_verify_data_free(AvbSlotVerifyData* data); 276 277 /* Performs a full verification of the slot identified by |ab_suffix| 278 * and load and verify the contents of the partitions whose name is in 279 * the NULL-terminated string array |requested_partitions| (each 280 * partition must use hash verification). If not using A/B, pass an 281 * empty string (e.g. "", not NULL) for |ab_suffix|. This parameter 282 * must include the leading underscore, for example "_a" should be 283 * used to refer to the first slot. 284 * 285 * Typically the |requested_partitions| array only contains a single 286 * item for the boot partition, 'boot'. 287 * 288 * Verification includes loading and verifying data from the 'vbmeta', 289 * the requested hash partitions, and possibly other partitions (with 290 * |ab_suffix| appended), inspecting rollback indexes, and checking if 291 * the public key used to sign the data is acceptable. The functions 292 * in |ops| will be used to do this. 293 * 294 * If |out_data| is not NULL, it will be set to a newly allocated 295 * |AvbSlotVerifyData| struct containing all the data needed to 296 * actually boot the slot. This data structure should be freed with 297 * avb_slot_verify_data_free() when you are done with it. See below 298 * for when this is returned. 299 * 300 * The |flags| parameter is used to influence the semantics of 301 * avb_slot_verify() - for example the 302 * AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR flag can be used to 303 * ignore verification errors which is something needed in the 304 * UNLOCKED state. See the AvbSlotVerifyFlags enumeration for details. 305 * 306 * The |hashtree_error_mode| parameter should be set to the desired 307 * error handling mode when hashtree validation fails inside the 308 * HLOS. This value isn't used by libavb per se - it is forwarded to 309 * the HLOS through the androidboot.veritymode and 310 * androidboot.vbmeta.invalidate_on_error cmdline parameters. See the 311 * AvbHashtreeErrorMode enumeration for details. 312 * 313 * Also note that |out_data| is never set if 314 * AVB_SLOT_VERIFY_RESULT_ERROR_OOM, AVB_SLOT_VERIFY_RESULT_ERROR_IO, 315 * or AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA is returned. 316 * 317 * AVB_SLOT_VERIFY_RESULT_OK is returned if everything is verified 318 * correctly and all public keys are accepted. 319 * 320 * AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED is returned if 321 * everything is verified correctly out but one or more public keys 322 * are not accepted. This includes the case where integrity data is 323 * not signed. 324 * 325 * AVB_SLOT_VERIFY_RESULT_ERROR_OOM is returned if unable to 326 * allocate memory. 327 * 328 * AVB_SLOT_VERIFY_RESULT_ERROR_IO is returned if an I/O error 329 * occurred while trying to load data or get a rollback index. 330 * 331 * AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION is returned if the data 332 * did not verify, e.g. the digest didn't match or signature checks 333 * failed. 334 * 335 * AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX is returned if a 336 * rollback index was less than its stored value. 337 * 338 * AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA is returned if some 339 * of the metadata is invalid or inconsistent. 340 * 341 * AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION is returned if 342 * some of the metadata requires a newer version of libavb than what 343 * is in use. 344 * 345 * AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT is returned if the 346 * caller passed invalid parameters, for example trying to use 347 * AVB_HASHTREE_ERROR_MODE_LOGGING without 348 * AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR. 349 */ 350 AvbSlotVerifyResult avb_slot_verify(AvbOps* ops, 351 const char* const* requested_partitions, 352 const char* ab_suffix, 353 AvbSlotVerifyFlags flags, 354 AvbHashtreeErrorMode hashtree_error_mode, 355 AvbSlotVerifyData** out_data); 356 357 #ifdef __cplusplus 358 } 359 #endif 360 361 #endif /* AVB_SLOT_VERIFY_H_ */ 362