1 /* SPDX-License-Identifier: MIT */ 2 /* 3 * Copyright (C) 2016 The Android Open Source Project 4 */ 5 6 #if !defined(AVB_INSIDE_LIBAVB_H) && !defined(AVB_COMPILATION) 7 #error "Never include this file directly, include libavb.h instead." 8 #endif 9 10 #ifndef AVB_SLOT_VERIFY_H_ 11 #define AVB_SLOT_VERIFY_H_ 12 13 #include "avb_ops.h" 14 #include "avb_vbmeta_image.h" 15 16 #ifdef __cplusplus 17 extern "C" { 18 #endif 19 20 /* Return codes used in avb_slot_verify(), see that function for 21 * documentation for each field. 22 * 23 * Use avb_slot_verify_result_to_string() to get a textual 24 * representation usable for error/debug output. 25 */ 26 typedef enum { 27 AVB_SLOT_VERIFY_RESULT_OK, 28 AVB_SLOT_VERIFY_RESULT_ERROR_OOM, 29 AVB_SLOT_VERIFY_RESULT_ERROR_IO, 30 AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION, 31 AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX, 32 AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED, 33 AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA, 34 AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION, 35 AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT 36 } AvbSlotVerifyResult; 37 38 /* Various error handling modes for when verification fails using a 39 * hashtree at runtime inside the HLOS. 40 * 41 * AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE means that the OS 42 * will invalidate the current slot and restart. 43 * 44 * AVB_HASHTREE_ERROR_MODE_RESTART means that the OS will restart. 45 * 46 * AVB_HASHTREE_ERROR_MODE_EIO means that an EIO error will be 47 * returned to applications. 48 * 49 * AVB_HASHTREE_ERROR_MODE_LOGGING means that errors will be logged 50 * and corrupt data may be returned to applications. This mode should 51 * be used ONLY for diagnostics and debugging. It cannot be used 52 * unless AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR is also 53 * used. 54 */ 55 typedef enum { 56 AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE, 57 AVB_HASHTREE_ERROR_MODE_RESTART, 58 AVB_HASHTREE_ERROR_MODE_EIO, 59 AVB_HASHTREE_ERROR_MODE_LOGGING 60 } AvbHashtreeErrorMode; 61 62 /* Flags that influence how avb_slot_verify() works. 63 * 64 * If AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR is NOT set then 65 * avb_slot_verify() will bail out as soon as an error is encountered 66 * and |out_data| is set only if AVB_SLOT_VERIFY_RESULT_OK is 67 * returned. 68 * 69 * Otherwise if AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR is set 70 * avb_slot_verify() will continue verification efforts and |out_data| 71 * is also set if AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED, 72 * AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION, or 73 * AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX is returned. It is 74 * undefined which error is returned if more than one distinct error 75 * is encountered. It is guaranteed that AVB_SLOT_VERIFY_RESULT_OK is 76 * returned if, and only if, there are no errors. This mode is needed 77 * to boot valid but unverified slots when the device is unlocked. 78 * 79 * Also, if AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR is set the 80 * contents loaded from |requested_partition| will be the contents of 81 * the entire partition instead of just the size specified in the hash 82 * descriptor. 83 */ 84 typedef enum { 85 AVB_SLOT_VERIFY_FLAGS_NONE = 0, 86 AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR = (1 << 0) 87 } AvbSlotVerifyFlags; 88 89 /* Get a textual representation of |result|. */ 90 const char* avb_slot_verify_result_to_string(AvbSlotVerifyResult result); 91 92 /* Maximum number of rollback index locations supported. */ 93 #define AVB_MAX_NUMBER_OF_ROLLBACK_INDEX_LOCATIONS 32 94 95 /* AvbPartitionData contains data loaded from partitions when using 96 * avb_slot_verify(). The |partition_name| field contains the name of 97 * the partition (without A/B suffix), |data| points to the loaded 98 * data which is |data_size| bytes long. If |preloaded| is set to true, 99 * this structure dose not own |data|. The caller of |avb_slot_verify| 100 * needs to make sure that the preloaded data outlives this 101 * |AvbPartitionData| structure. 102 * 103 * Note that this is strictly less than the partition size - it's only 104 * the image stored there, not the entire partition nor any of the 105 * metadata. 106 */ 107 typedef struct { 108 char* partition_name; 109 uint8_t* data; 110 size_t data_size; 111 bool preloaded; 112 } AvbPartitionData; 113 114 /* AvbVBMetaData contains a vbmeta struct loaded from a partition when 115 * using avb_slot_verify(). The |partition_name| field contains the 116 * name of the partition (without A/B suffix), |vbmeta_data| points to 117 * the loaded data which is |vbmeta_size| bytes long. 118 * 119 * The |verify_result| field contains the result of 120 * avb_vbmeta_image_verify() on the data. This is guaranteed to be 121 * AVB_VBMETA_VERIFY_RESULT_OK for all vbmeta images if 122 * avb_slot_verify() returns AVB_SLOT_VERIFY_RESULT_OK. 123 * 124 * You can use avb_descriptor_get_all(), avb_descriptor_foreach(), and 125 * avb_vbmeta_image_header_to_host_byte_order() with this data. 126 */ 127 typedef struct { 128 char* partition_name; 129 uint8_t* vbmeta_data; 130 size_t vbmeta_size; 131 AvbVBMetaVerifyResult verify_result; 132 } AvbVBMetaData; 133 134 /* AvbSlotVerifyData contains data needed to boot a particular slot 135 * and is returned by avb_slot_verify() if partitions in a slot are 136 * successfully verified. 137 * 138 * All data pointed to by this struct - including data in each item in 139 * the |partitions| array - will be freed when the 140 * avb_slot_verify_data_free() function is called. 141 * 142 * The |ab_suffix| field is the copy of the of |ab_suffix| field 143 * passed to avb_slot_verify(). It is the A/B suffix of the slot. This 144 * value includes the leading underscore - typical values are "" (if 145 * no slots are in use), "_a" (for the first slot), and "_b" (for the 146 * second slot). 147 * 148 * The VBMeta images that were checked are available in the 149 * |vbmeta_images| field. The field |num_vbmeta_images| contains the 150 * number of elements in this array. The first element - 151 * vbmeta_images[0] - is guaranteed to be from the partition with the 152 * top-level vbmeta struct. This is usually the "vbmeta" partition in 153 * the requested slot but if there is no "vbmeta" partition it can 154 * also be the "boot" partition. 155 * 156 * The partitions loaded and verified from from the slot are 157 * accessible in the |loaded_partitions| array. The field 158 * |num_loaded_partitions| contains the number of elements in this 159 * array. The order of partitions in this array may not necessarily be 160 * the same order as in the passed-in |requested_partitions| array. 161 * 162 * Rollback indexes for the verified slot are stored in the 163 * |rollback_indexes| field. Note that avb_slot_verify() will NEVER 164 * modify stored_rollback_index[n] locations e.g. it will never use 165 * the write_rollback_index() AvbOps operation. Instead it is the job 166 * of the caller of avb_slot_verify() to do this based on e.g. A/B 167 * policy and other factors. See libavb_ab/avb_ab_flow.c for an 168 * example of how to do this. 169 * 170 * The |cmdline| field is a NUL-terminated string in UTF-8 resulting 171 * from concatenating all |AvbKernelCmdlineDescriptor| and then 172 * performing proper substitution of the variables 173 * $(ANDROID_SYSTEM_PARTUUID), $(ANDROID_BOOT_PARTUUID), and 174 * $(ANDROID_VBMETA_PARTUUID) using the 175 * get_unique_guid_for_partition() operation in |AvbOps|. Additionally 176 * $(ANDROID_VERITY_MODE) will be replaced with the proper dm-verity 177 * option depending on the value of |hashtree_error_mode|. 178 * 179 * Additionally, the |cmdline| field will have the following kernel 180 * command-line options set (unless verification is disabled, see 181 * below): 182 * 183 * androidboot.veritymode: This is set to 'disabled' if the 184 * AVB_VBMETA_IMAGE_FLAGS_HASHTREE_DISABLED flag is set in top-level 185 * vbmeta struct. Otherwise it is set to 'enforcing' if the 186 * passed-in hashtree error mode is AVB_HASHTREE_ERROR_MODE_RESTART 187 * or AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE, 'eio' if it's 188 * set to AVB_HASHTREE_ERROR_MODE_EIO, and 'logging' if it's set to 189 * AVB_HASHTREE_ERROR_MODE_LOGGING. 190 * 191 * androidboot.vbmeta.invalidate_on_error: This is set to 'yes' only 192 * if hashtree validation isn't disabled and the passed-in hashtree 193 * error mode is AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE. 194 * 195 * androidboot.vbmeta.device_state: set to "locked" or "unlocked" 196 * depending on the result of the result of AvbOps's 197 * read_is_unlocked() function. 198 * 199 * androidboot.vbmeta.{hash_alg, size, digest}: Will be set to 200 * the digest of all images in |vbmeta_images|. 201 * 202 * androidboot.vbmeta.device: This is set to the value 203 * PARTUUID=$(ANDROID_VBMETA_PARTUUID) before substitution so it 204 * will end up pointing to the vbmeta partition for the verified 205 * slot. If there is no vbmeta partition it will point to the boot 206 * partition of the verified slot. 207 * 208 * androidboot.vbmeta.avb_version: This is set to the decimal value 209 * of AVB_VERSION_MAJOR followed by a dot followed by the decimal 210 * value of AVB_VERSION_MINOR, for example "1.0" or "1.4". This 211 * version number represents the vbmeta file format version 212 * supported by libavb copy used in the boot loader. This is not 213 * necessarily the same version number of the on-disk metadata for 214 * the slot that was verified. 215 * 216 * Note that androidboot.slot_suffix is not set in the |cmdline| field 217 * in |AvbSlotVerifyData| - you will have to set this yourself. 218 * 219 * If the |AVB_VBMETA_IMAGE_FLAGS_VERIFICATION_DISABLED| flag is set 220 * in the top-level vbmeta struct then only the top-level vbmeta 221 * struct is verified and descriptors will not processed. The return 222 * value will be set accordingly (if this flag is set via 'avbctl 223 * disable-verification' then the return value will be 224 * |AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION|) and 225 * |AvbSlotVerifyData| is returned. Additionally all partitions in the 226 * |requested_partitions| are loaded and the |cmdline| field is set to 227 * "root=PARTUUID=$(ANDROID_SYSTEM_PARTUUID)" and the GUID for the 228 * appropriate system partition is substituted in. Note that none of 229 * the androidboot.* options mentioned above will be set. 230 * 231 * This struct may grow in the future without it being considered an 232 * ABI break. 233 */ 234 typedef struct { 235 char* ab_suffix; 236 AvbVBMetaData* vbmeta_images; 237 size_t num_vbmeta_images; 238 AvbPartitionData* loaded_partitions; 239 size_t num_loaded_partitions; 240 char* cmdline; 241 uint64_t rollback_indexes[AVB_MAX_NUMBER_OF_ROLLBACK_INDEX_LOCATIONS]; 242 } AvbSlotVerifyData; 243 244 /* Calculates a digest of all vbmeta images in |data| using 245 * the digest indicated by |digest_type|. Stores the result 246 * in |out_digest| which must be large enough to hold a digest 247 * of the requested type. 248 */ 249 void avb_slot_verify_data_calculate_vbmeta_digest(AvbSlotVerifyData* data, 250 AvbDigestType digest_type, 251 uint8_t* out_digest); 252 253 /* Frees a |AvbSlotVerifyData| including all data it points to. */ 254 void avb_slot_verify_data_free(AvbSlotVerifyData* data); 255 256 /* Performs a full verification of the slot identified by |ab_suffix| 257 * and load and verify the contents of the partitions whose name is in 258 * the NULL-terminated string array |requested_partitions| (each 259 * partition must use hash verification). If not using A/B, pass an 260 * empty string (e.g. "", not NULL) for |ab_suffix|. This parameter 261 * must include the leading underscore, for example "_a" should be 262 * used to refer to the first slot. 263 * 264 * Typically the |requested_partitions| array only contains a single 265 * item for the boot partition, 'boot'. 266 * 267 * Verification includes loading and verifying data from the 'vbmeta', 268 * the requested hash partitions, and possibly other partitions (with 269 * |ab_suffix| appended), inspecting rollback indexes, and checking if 270 * the public key used to sign the data is acceptable. The functions 271 * in |ops| will be used to do this. 272 * 273 * If |out_data| is not NULL, it will be set to a newly allocated 274 * |AvbSlotVerifyData| struct containing all the data needed to 275 * actually boot the slot. This data structure should be freed with 276 * avb_slot_verify_data_free() when you are done with it. See below 277 * for when this is returned. 278 * 279 * The |flags| parameter is used to influence the semantics of 280 * avb_slot_verify() - for example the 281 * AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR flag can be used to 282 * ignore verification errors which is something needed in the 283 * UNLOCKED state. See the AvbSlotVerifyFlags enumeration for details. 284 * 285 * The |hashtree_error_mode| parameter should be set to the desired 286 * error handling mode when hashtree validation fails inside the 287 * HLOS. This value isn't used by libavb per se - it is forwarded to 288 * the HLOS through the androidboot.veritymode and 289 * androidboot.vbmeta.invalidate_on_error cmdline parameters. See the 290 * AvbHashtreeErrorMode enumeration for details. 291 * 292 * Also note that |out_data| is never set if 293 * AVB_SLOT_VERIFY_RESULT_ERROR_OOM, AVB_SLOT_VERIFY_RESULT_ERROR_IO, 294 * or AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA is returned. 295 * 296 * AVB_SLOT_VERIFY_RESULT_OK is returned if everything is verified 297 * correctly and all public keys are accepted. 298 * 299 * AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED is returned if 300 * everything is verified correctly out but one or more public keys 301 * are not accepted. This includes the case where integrity data is 302 * not signed. 303 * 304 * AVB_SLOT_VERIFY_RESULT_ERROR_OOM is returned if unable to 305 * allocate memory. 306 * 307 * AVB_SLOT_VERIFY_RESULT_ERROR_IO is returned if an I/O error 308 * occurred while trying to load data or get a rollback index. 309 * 310 * AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION is returned if the data 311 * did not verify, e.g. the digest didn't match or signature checks 312 * failed. 313 * 314 * AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX is returned if a 315 * rollback index was less than its stored value. 316 * 317 * AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA is returned if some 318 * of the metadata is invalid or inconsistent. 319 * 320 * AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION is returned if 321 * some of the metadata requires a newer version of libavb than what 322 * is in use. 323 * 324 * AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT is returned if the 325 * caller passed invalid parameters, for example trying to use 326 * AVB_HASHTREE_ERROR_MODE_LOGGING without 327 * AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR. 328 */ 329 AvbSlotVerifyResult avb_slot_verify(AvbOps* ops, 330 const char* const* requested_partitions, 331 const char* ab_suffix, 332 AvbSlotVerifyFlags flags, 333 AvbHashtreeErrorMode hashtree_error_mode, 334 AvbSlotVerifyData** out_data); 335 336 #ifdef __cplusplus 337 } 338 #endif 339 340 #endif /* AVB_SLOT_VERIFY_H_ */ 341
