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. 120 * 121 * Note that this is strictly less than the partition size - it's only 122 * the image stored there, not the entire partition nor any of the 123 * metadata. 124 */ 125 typedef struct { 126 char* partition_name; 127 uint8_t* data; 128 size_t data_size; 129 } AvbPartitionData; 130 131 /* AvbVBMetaData contains a vbmeta struct loaded from a partition when 132 * using avb_slot_verify(). The |partition_name| field contains the 133 * name of the partition (without A/B suffix), |vbmeta_data| points to 134 * the loaded data which is |vbmeta_size| bytes long. 135 * 136 * The |verify_result| field contains the result of 137 * avb_vbmeta_image_verify() on the data. This is guaranteed to be 138 * AVB_VBMETA_VERIFY_RESULT_OK for all vbmeta images if 139 * avb_slot_verify() returns AVB_SLOT_VERIFY_RESULT_OK. 140 * 141 * You can use avb_descriptor_get_all(), avb_descriptor_foreach(), and 142 * avb_vbmeta_image_header_to_host_byte_order() with this data. 143 */ 144 typedef struct { 145 char* partition_name; 146 uint8_t* vbmeta_data; 147 size_t vbmeta_size; 148 AvbVBMetaVerifyResult verify_result; 149 } AvbVBMetaData; 150 151 /* AvbSlotVerifyData contains data needed to boot a particular slot 152 * and is returned by avb_slot_verify() if partitions in a slot are 153 * successfully verified. 154 * 155 * All data pointed to by this struct - including data in each item in 156 * the |partitions| array - will be freed when the 157 * avb_slot_verify_data_free() function is called. 158 * 159 * The |ab_suffix| field is the copy of the of |ab_suffix| field 160 * passed to avb_slot_verify(). It is the A/B suffix of the slot. This 161 * value includes the leading underscore - typical values are "" (if 162 * no slots are in use), "_a" (for the first slot), and "_b" (for the 163 * second slot). 164 * 165 * The VBMeta images that were checked are available in the 166 * |vbmeta_images| field. The field |num_vbmeta_images| contains the 167 * number of elements in this array. The first element - 168 * vbmeta_images[0] - is guaranteed to be from the partition with the 169 * top-level vbmeta struct. This is usually the "vbmeta" partition in 170 * the requested slot but if there is no "vbmeta" partition it can 171 * also be the "boot" partition. 172 * 173 * The partitions loaded and verified from from the slot are 174 * accessible in the |loaded_partitions| array. The field 175 * |num_loaded_partitions| contains the number of elements in this 176 * array. The order of partitions in this array may not necessarily be 177 * the same order as in the passed-in |requested_partitions| array. 178 * 179 * Rollback indexes for the verified slot are stored in the 180 * |rollback_indexes| field. Note that avb_slot_verify() will NEVER 181 * modify stored_rollback_index[n] locations e.g. it will never use 182 * the write_rollback_index() AvbOps operation. Instead it is the job 183 * of the caller of avb_slot_verify() to do this based on e.g. A/B 184 * policy and other factors. See libavb_ab/avb_ab_flow.c for an 185 * example of how to do this. 186 * 187 * The |cmdline| field is a NUL-terminated string in UTF-8 resulting 188 * from concatenating all |AvbKernelCmdlineDescriptor| and then 189 * performing proper substitution of the variables 190 * $(ANDROID_SYSTEM_PARTUUID), $(ANDROID_BOOT_PARTUUID), and 191 * $(ANDROID_VBMETA_PARTUUID) using the 192 * get_unique_guid_for_partition() operation in |AvbOps|. Additionally 193 * $(ANDROID_VERITY_MODE) will be replaced with the proper dm-verity 194 * option depending on the value of |hashtree_error_mode|. 195 * 196 * Additionally, the |cmdline| field will have the following kernel 197 * command-line options set: 198 * 199 * androidboot.veritymode: This is set to 'disabled' if the 200 * AVB_VBMETA_IMAGE_FLAGS_HASHTREE_DISABLED flag is set in top-level 201 * vbmeta struct. Otherwise it is set to 'enforcing' if the 202 * passed-in hashtree error mode is AVB_HASHTREE_ERROR_MODE_RESTART 203 * or AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE, 'eio' if it's 204 * set to AVB_HASHTREE_ERROR_MODE_EIO, and 'logging' if it's set to 205 * AVB_HASHTREE_ERROR_MODE_LOGGING. 206 * 207 * androidboot.vbmeta.invalidate_on_error: This is set to 'yes' only 208 * if hashtree validation isn't disabled and the passed-in hashtree 209 * error mode is AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE. 210 * 211 * androidboot.vbmeta.device_state: set to "locked" or "unlocked" 212 * depending on the result of the result of AvbOps's 213 * read_is_unlocked() function. 214 * 215 * androidboot.vbmeta.{hash_alg, size, digest}: Will be set to 216 * the digest of all images in |vbmeta_images|. 217 * 218 * androidboot.vbmeta.device: This is set to the value 219 * PARTUUID=$(ANDROID_VBMETA_PARTUUID) before substitution so it 220 * will end up pointing to the vbmeta partition for the verified 221 * slot. If there is no vbmeta partition it will point to the boot 222 * partition of the verified slot. 223 * 224 * androidboot.vbmeta.avb_version: This is set to the decimal value 225 * of AVB_VERSION_MAJOR followed by a dot followed by the decimal 226 * value of AVB_VERSION_MINOR, for example "1.0" or "1.4". This 227 * version number represents the vbmeta file format version 228 * supported by libavb copy used in the boot loader. This is not 229 * necessarily the same version number of the on-disk metadata for 230 * the slot that was verified. 231 * 232 * Note that neither androidboot.slot_suffix nor androidboot.slot are 233 * set in the |cmdline| field in |AvbSlotVerifyData| - you will have 234 * to pass these yourself. 235 * 236 * Also note that androidboot.veritymode is set by libavb and since 237 * AVB only supports 'enforcing' and 'disabled' values, the boot 238 * loader is relieved of managing any state related to dm-verity or 239 * setting this cmdline parameter. 240 * 241 * This struct may grow in the future without it being considered an 242 * ABI break. 243 */ 244 typedef struct { 245 char* ab_suffix; 246 AvbVBMetaData* vbmeta_images; 247 size_t num_vbmeta_images; 248 AvbPartitionData* loaded_partitions; 249 size_t num_loaded_partitions; 250 char* cmdline; 251 uint64_t rollback_indexes[AVB_MAX_NUMBER_OF_ROLLBACK_INDEX_LOCATIONS]; 252 } AvbSlotVerifyData; 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