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