1 /* 2 * Copyright (C) 2016 The Android Open Source Project 3 * 4 * SPDX-License-Identifier: MIT 5 */ 6 7 #if !defined(AVB_INSIDE_LIBAVB_H) && !defined(AVB_COMPILATION) 8 #error "Never include this file directly, include libavb.h instead." 9 #endif 10 11 #ifndef AVB_SLOT_VERIFY_H_ 12 #define AVB_SLOT_VERIFY_H_ 13 14 #include "avb_ops.h" 15 #include "avb_vbmeta_image.h" 16 17 #ifdef __cplusplus 18 extern "C" { 19 #endif 20 21 /* Return codes used in avb_slot_verify(), see that function for 22 * documentation for each field. 23 * 24 * Use avb_slot_verify_result_to_string() to get a textual 25 * representation usable for error/debug output. 26 */ 27 typedef enum { 28 AVB_SLOT_VERIFY_RESULT_OK, 29 AVB_SLOT_VERIFY_RESULT_ERROR_OOM, 30 AVB_SLOT_VERIFY_RESULT_ERROR_IO, 31 AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION, 32 AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX, 33 AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED, 34 AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA, 35 AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION, 36 AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT 37 } AvbSlotVerifyResult; 38 39 /* Various error handling modes for when verification fails using a 40 * hashtree at runtime inside the HLOS. 41 * 42 * AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE means that the OS 43 * will invalidate the current slot and restart. 44 * 45 * AVB_HASHTREE_ERROR_MODE_RESTART means that the OS will restart. 46 * 47 * AVB_HASHTREE_ERROR_MODE_EIO means that an EIO error will be 48 * returned to applications. 49 * 50 * AVB_HASHTREE_ERROR_MODE_LOGGING means that errors will be logged 51 * and corrupt data may be returned to applications. This mode should 52 * be used ONLY for diagnostics and debugging. It cannot be used 53 * unless AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR is also 54 * used. 55 */ 56 typedef enum { 57 AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE, 58 AVB_HASHTREE_ERROR_MODE_RESTART, 59 AVB_HASHTREE_ERROR_MODE_EIO, 60 AVB_HASHTREE_ERROR_MODE_LOGGING 61 } AvbHashtreeErrorMode; 62 63 /* Flags that influence how avb_slot_verify() works. 64 * 65 * If AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR is NOT set then 66 * avb_slot_verify() will bail out as soon as an error is encountered 67 * and |out_data| is set only if AVB_SLOT_VERIFY_RESULT_OK is 68 * returned. 69 * 70 * Otherwise if AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR is set 71 * avb_slot_verify() will continue verification efforts and |out_data| 72 * is also set if AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED, 73 * AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION, or 74 * AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX is returned. It is 75 * undefined which error is returned if more than one distinct error 76 * is encountered. It is guaranteed that AVB_SLOT_VERIFY_RESULT_OK is 77 * returned if, and only if, there are no errors. This mode is needed 78 * to boot valid but unverified slots when the device is unlocked. 79 * 80 * Also, if AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR is set the 81 * contents loaded from |requested_partition| will be the contents of 82 * the entire partition instead of just the size specified in the hash 83 * descriptor. 84 */ 85 typedef enum { 86 AVB_SLOT_VERIFY_FLAGS_NONE = 0, 87 AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR = (1 << 0) 88 } AvbSlotVerifyFlags; 89 90 /* Get a textual representation of |result|. */ 91 const char* avb_slot_verify_result_to_string(AvbSlotVerifyResult result); 92 93 /* Maximum number of rollback index locations supported. */ 94 #define AVB_MAX_NUMBER_OF_ROLLBACK_INDEX_LOCATIONS 32 95 96 /* AvbPartitionData contains data loaded from partitions when using 97 * avb_slot_verify(). The |partition_name| field contains the name of 98 * the partition (without A/B suffix), |data| points to the loaded 99 * data which is |data_size| bytes long. If |preloaded| is set to true, 100 * this structure dose not own |data|. The caller of |avb_slot_verify| 101 * needs to make sure that the preloaded data outlives this 102 * |AvbPartitionData| structure. 103 * 104 * Note that this is strictly less than the partition size - it's only 105 * the image stored there, not the entire partition nor any of the 106 * metadata. 107 */ 108 typedef struct { 109 char* partition_name; 110 uint8_t* data; 111 size_t data_size; 112 bool preloaded; 113 } AvbPartitionData; 114 115 /* AvbVBMetaData contains a vbmeta struct loaded from a partition when 116 * using avb_slot_verify(). The |partition_name| field contains the 117 * name of the partition (without A/B suffix), |vbmeta_data| points to 118 * the loaded data which is |vbmeta_size| bytes long. 119 * 120 * The |verify_result| field contains the result of 121 * avb_vbmeta_image_verify() on the data. This is guaranteed to be 122 * AVB_VBMETA_VERIFY_RESULT_OK for all vbmeta images if 123 * avb_slot_verify() returns AVB_SLOT_VERIFY_RESULT_OK. 124 * 125 * You can use avb_descriptor_get_all(), avb_descriptor_foreach(), and 126 * avb_vbmeta_image_header_to_host_byte_order() with this data. 127 */ 128 typedef struct { 129 char* partition_name; 130 uint8_t* vbmeta_data; 131 size_t vbmeta_size; 132 AvbVBMetaVerifyResult verify_result; 133 } AvbVBMetaData; 134 135 /* AvbSlotVerifyData contains data needed to boot a particular slot 136 * and is returned by avb_slot_verify() if partitions in a slot are 137 * successfully verified. 138 * 139 * All data pointed to by this struct - including data in each item in 140 * the |partitions| array - will be freed when the 141 * avb_slot_verify_data_free() function is called. 142 * 143 * The |ab_suffix| field is the copy of the of |ab_suffix| field 144 * passed to avb_slot_verify(). It is the A/B suffix of the slot. This 145 * value includes the leading underscore - typical values are "" (if 146 * no slots are in use), "_a" (for the first slot), and "_b" (for the 147 * second slot). 148 * 149 * The VBMeta images that were checked are available in the 150 * |vbmeta_images| field. The field |num_vbmeta_images| contains the 151 * number of elements in this array. The first element - 152 * vbmeta_images[0] - is guaranteed to be from the partition with the 153 * top-level vbmeta struct. This is usually the "vbmeta" partition in 154 * the requested slot but if there is no "vbmeta" partition it can 155 * also be the "boot" partition. 156 * 157 * The partitions loaded and verified from from the slot are 158 * accessible in the |loaded_partitions| array. The field 159 * |num_loaded_partitions| contains the number of elements in this 160 * array. The order of partitions in this array may not necessarily be 161 * the same order as in the passed-in |requested_partitions| array. 162 * 163 * Rollback indexes for the verified slot are stored in the 164 * |rollback_indexes| field. Note that avb_slot_verify() will NEVER 165 * modify stored_rollback_index[n] locations e.g. it will never use 166 * the write_rollback_index() AvbOps operation. Instead it is the job 167 * of the caller of avb_slot_verify() to do this based on e.g. A/B 168 * policy and other factors. See libavb_ab/avb_ab_flow.c for an 169 * example of how to do this. 170 * 171 * The |cmdline| field is a NUL-terminated string in UTF-8 resulting 172 * from concatenating all |AvbKernelCmdlineDescriptor| and then 173 * performing proper substitution of the variables 174 * $(ANDROID_SYSTEM_PARTUUID), $(ANDROID_BOOT_PARTUUID), and 175 * $(ANDROID_VBMETA_PARTUUID) using the 176 * get_unique_guid_for_partition() operation in |AvbOps|. Additionally 177 * $(ANDROID_VERITY_MODE) will be replaced with the proper dm-verity 178 * option depending on the value of |hashtree_error_mode|. 179 * 180 * Additionally, the |cmdline| field will have the following kernel 181 * command-line options set (unless verification is disabled, see 182 * below): 183 * 184 * androidboot.veritymode: This is set to 'disabled' if the 185 * AVB_VBMETA_IMAGE_FLAGS_HASHTREE_DISABLED flag is set in top-level 186 * vbmeta struct. Otherwise it is set to 'enforcing' if the 187 * passed-in hashtree error mode is AVB_HASHTREE_ERROR_MODE_RESTART 188 * or AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE, 'eio' if it's 189 * set to AVB_HASHTREE_ERROR_MODE_EIO, and 'logging' if it's set to 190 * AVB_HASHTREE_ERROR_MODE_LOGGING. 191 * 192 * androidboot.vbmeta.invalidate_on_error: This is set to 'yes' only 193 * if hashtree validation isn't disabled and the passed-in hashtree 194 * error mode is AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE. 195 * 196 * androidboot.vbmeta.device_state: set to "locked" or "unlocked" 197 * depending on the result of the result of AvbOps's 198 * read_is_unlocked() function. 199 * 200 * androidboot.vbmeta.{hash_alg, size, digest}: Will be set to 201 * the digest of all images in |vbmeta_images|. 202 * 203 * androidboot.vbmeta.device: This is set to the value 204 * PARTUUID=$(ANDROID_VBMETA_PARTUUID) before substitution so it 205 * will end up pointing to the vbmeta partition for the verified 206 * slot. If there is no vbmeta partition it will point to the boot 207 * partition of the verified slot. 208 * 209 * androidboot.vbmeta.avb_version: This is set to the decimal value 210 * of AVB_VERSION_MAJOR followed by a dot followed by the decimal 211 * value of AVB_VERSION_MINOR, for example "1.0" or "1.4". This 212 * version number represents the vbmeta file format version 213 * supported by libavb copy used in the boot loader. This is not 214 * necessarily the same version number of the on-disk metadata for 215 * the slot that was verified. 216 * 217 * Note that androidboot.slot_suffix is not set in the |cmdline| field 218 * in |AvbSlotVerifyData| - you will have to set this yourself. 219 * 220 * If the |AVB_VBMETA_IMAGE_FLAGS_VERIFICATION_DISABLED| flag is set 221 * in the top-level vbmeta struct then only the top-level vbmeta 222 * struct is verified and descriptors will not processed. The return 223 * value will be set accordingly (if this flag is set via 'avbctl 224 * disable-verification' then the return value will be 225 * |AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION|) and 226 * |AvbSlotVerifyData| is returned. Additionally all partitions in the 227 * |requested_partitions| are loaded and the |cmdline| field is set to 228 * "root=PARTUUID=$(ANDROID_SYSTEM_PARTUUID)" and the GUID for the 229 * appropriate system partition is substituted in. Note that none of 230 * the androidboot.* options mentioned above will be set. 231 * 232 * This struct may grow in the future without it being considered an 233 * ABI break. 234 */ 235 typedef struct { 236 char* ab_suffix; 237 AvbVBMetaData* vbmeta_images; 238 size_t num_vbmeta_images; 239 AvbPartitionData* loaded_partitions; 240 size_t num_loaded_partitions; 241 char* cmdline; 242 uint64_t rollback_indexes[AVB_MAX_NUMBER_OF_ROLLBACK_INDEX_LOCATIONS]; 243 } AvbSlotVerifyData; 244 245 /* Calculates a digest of all vbmeta images in |data| using 246 * the digest indicated by |digest_type|. Stores the result 247 * in |out_digest| which must be large enough to hold a digest 248 * of the requested type. 249 */ 250 void avb_slot_verify_data_calculate_vbmeta_digest(AvbSlotVerifyData* data, 251 AvbDigestType digest_type, 252 uint8_t* out_digest); 253 254 /* Frees a |AvbSlotVerifyData| including all data it points to. */ 255 void avb_slot_verify_data_free(AvbSlotVerifyData* data); 256 257 /* Performs a full verification of the slot identified by |ab_suffix| 258 * and load and verify the contents of the partitions whose name is in 259 * the NULL-terminated string array |requested_partitions| (each 260 * partition must use hash verification). If not using A/B, pass an 261 * empty string (e.g. "", not NULL) for |ab_suffix|. This parameter 262 * must include the leading underscore, for example "_a" should be 263 * used to refer to the first slot. 264 * 265 * Typically the |requested_partitions| array only contains a single 266 * item for the boot partition, 'boot'. 267 * 268 * Verification includes loading and verifying data from the 'vbmeta', 269 * the requested hash partitions, and possibly other partitions (with 270 * |ab_suffix| appended), inspecting rollback indexes, and checking if 271 * the public key used to sign the data is acceptable. The functions 272 * in |ops| will be used to do this. 273 * 274 * If |out_data| is not NULL, it will be set to a newly allocated 275 * |AvbSlotVerifyData| struct containing all the data needed to 276 * actually boot the slot. This data structure should be freed with 277 * avb_slot_verify_data_free() when you are done with it. See below 278 * for when this is returned. 279 * 280 * The |flags| parameter is used to influence the semantics of 281 * avb_slot_verify() - for example the 282 * AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR flag can be used to 283 * ignore verification errors which is something needed in the 284 * UNLOCKED state. See the AvbSlotVerifyFlags enumeration for details. 285 * 286 * The |hashtree_error_mode| parameter should be set to the desired 287 * error handling mode when hashtree validation fails inside the 288 * HLOS. This value isn't used by libavb per se - it is forwarded to 289 * the HLOS through the androidboot.veritymode and 290 * androidboot.vbmeta.invalidate_on_error cmdline parameters. See the 291 * AvbHashtreeErrorMode enumeration for details. 292 * 293 * Also note that |out_data| is never set if 294 * AVB_SLOT_VERIFY_RESULT_ERROR_OOM, AVB_SLOT_VERIFY_RESULT_ERROR_IO, 295 * or AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA is returned. 296 * 297 * AVB_SLOT_VERIFY_RESULT_OK is returned if everything is verified 298 * correctly and all public keys are accepted. 299 * 300 * AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED is returned if 301 * everything is verified correctly out but one or more public keys 302 * are not accepted. This includes the case where integrity data is 303 * not signed. 304 * 305 * AVB_SLOT_VERIFY_RESULT_ERROR_OOM is returned if unable to 306 * allocate memory. 307 * 308 * AVB_SLOT_VERIFY_RESULT_ERROR_IO is returned if an I/O error 309 * occurred while trying to load data or get a rollback index. 310 * 311 * AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION is returned if the data 312 * did not verify, e.g. the digest didn't match or signature checks 313 * failed. 314 * 315 * AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX is returned if a 316 * rollback index was less than its stored value. 317 * 318 * AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA is returned if some 319 * of the metadata is invalid or inconsistent. 320 * 321 * AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION is returned if 322 * some of the metadata requires a newer version of libavb than what 323 * is in use. 324 * 325 * AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT is returned if the 326 * caller passed invalid parameters, for example trying to use 327 * AVB_HASHTREE_ERROR_MODE_LOGGING without 328 * AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR. 329 */ 330 AvbSlotVerifyResult avb_slot_verify(AvbOps* ops, 331 const char* const* requested_partitions, 332 const char* ab_suffix, 333 AvbSlotVerifyFlags flags, 334 AvbHashtreeErrorMode hashtree_error_mode, 335 AvbSlotVerifyData** out_data); 336 337 #ifdef __cplusplus 338 } 339 #endif 340 341 #endif /* AVB_SLOT_VERIFY_H_ */ 342