1 // SPDX-License-Identifier: MIT 2 /* 3 * Copyright (C) 2016 The Android Open Source Project 4 */ 5 6 #include "avb_cmdline.h" 7 #include "avb_sha.h" 8 #include "avb_util.h" 9 #include "avb_version.h" 10 11 #define NUM_GUIDS 3 12 13 /* Substitutes all variables (e.g. $(ANDROID_SYSTEM_PARTUUID)) with 14 * values. Returns NULL on OOM, otherwise the cmdline with values 15 * replaced. 16 */ 17 char* avb_sub_cmdline(AvbOps* ops, 18 const char* cmdline, 19 const char* ab_suffix, 20 bool using_boot_for_vbmeta, 21 const AvbCmdlineSubstList* additional_substitutions) { 22 const char* part_name_str[NUM_GUIDS] = {"system", "boot", "vbmeta"}; 23 const char* replace_str[NUM_GUIDS] = {"$(ANDROID_SYSTEM_PARTUUID)", 24 "$(ANDROID_BOOT_PARTUUID)", 25 "$(ANDROID_VBMETA_PARTUUID)"}; 26 char* ret = NULL; 27 AvbIOResult io_ret; 28 size_t n; 29 30 /* Special-case for when the top-level vbmeta struct is in the boot 31 * partition. 32 */ 33 if (using_boot_for_vbmeta) { 34 part_name_str[2] = "boot"; 35 } 36 37 /* Replace unique partition GUIDs */ 38 for (n = 0; n < NUM_GUIDS; n++) { 39 char part_name[AVB_PART_NAME_MAX_SIZE]; 40 char guid_buf[37]; 41 42 if (!avb_str_concat(part_name, 43 sizeof part_name, 44 part_name_str[n], 45 avb_strlen(part_name_str[n]), 46 ab_suffix, 47 avb_strlen(ab_suffix))) { 48 avb_error("Partition name and suffix does not fit.\n"); 49 goto fail; 50 } 51 52 io_ret = ops->get_unique_guid_for_partition( 53 ops, part_name, guid_buf, sizeof guid_buf); 54 if (io_ret == AVB_IO_RESULT_ERROR_OOM) { 55 goto fail; 56 } else if (io_ret != AVB_IO_RESULT_OK) { 57 avb_error("Error getting unique GUID for partition.\n"); 58 goto fail; 59 } 60 61 if (ret == NULL) { 62 ret = avb_replace(cmdline, replace_str[n], guid_buf); 63 } else { 64 char* new_ret = avb_replace(ret, replace_str[n], guid_buf); 65 avb_free(ret); 66 ret = new_ret; 67 } 68 if (ret == NULL) { 69 goto fail; 70 } 71 } 72 73 avb_assert(ret != NULL); 74 75 /* Replace any additional substitutions. */ 76 if (additional_substitutions != NULL) { 77 for (n = 0; n < additional_substitutions->size; ++n) { 78 char* new_ret = avb_replace(ret, 79 additional_substitutions->tokens[n], 80 additional_substitutions->values[n]); 81 avb_free(ret); 82 ret = new_ret; 83 if (ret == NULL) { 84 goto fail; 85 } 86 } 87 } 88 89 return ret; 90 91 fail: 92 if (ret != NULL) { 93 avb_free(ret); 94 } 95 return NULL; 96 } 97 98 static int cmdline_append_option(AvbSlotVerifyData* slot_data, 99 const char* key, 100 const char* value) { 101 size_t offset, key_len, value_len; 102 char* new_cmdline; 103 104 key_len = avb_strlen(key); 105 value_len = avb_strlen(value); 106 107 offset = 0; 108 if (slot_data->cmdline != NULL) { 109 offset = avb_strlen(slot_data->cmdline); 110 if (offset > 0) { 111 offset += 1; 112 } 113 } 114 115 new_cmdline = avb_calloc(offset + key_len + value_len + 2); 116 if (new_cmdline == NULL) { 117 return 0; 118 } 119 if (offset > 0) { 120 avb_memcpy(new_cmdline, slot_data->cmdline, offset - 1); 121 new_cmdline[offset - 1] = ' '; 122 } 123 avb_memcpy(new_cmdline + offset, key, key_len); 124 new_cmdline[offset + key_len] = '='; 125 avb_memcpy(new_cmdline + offset + key_len + 1, value, value_len); 126 if (slot_data->cmdline != NULL) { 127 avb_free(slot_data->cmdline); 128 } 129 slot_data->cmdline = new_cmdline; 130 131 return 1; 132 } 133 134 #define AVB_MAX_DIGITS_UINT64 32 135 136 /* Writes |value| to |digits| in base 10 followed by a NUL byte. 137 * Returns number of characters written excluding the NUL byte. 138 */ 139 static size_t uint64_to_base10(uint64_t value, 140 char digits[AVB_MAX_DIGITS_UINT64]) { 141 char rev_digits[AVB_MAX_DIGITS_UINT64]; 142 size_t n, num_digits; 143 144 for (num_digits = 0; num_digits < AVB_MAX_DIGITS_UINT64 - 1;) { 145 rev_digits[num_digits++] = avb_div_by_10(&value) + '0'; 146 if (value == 0) { 147 break; 148 } 149 } 150 151 for (n = 0; n < num_digits; n++) { 152 digits[n] = rev_digits[num_digits - 1 - n]; 153 } 154 digits[n] = '\0'; 155 return n; 156 } 157 158 static int cmdline_append_version(AvbSlotVerifyData* slot_data, 159 const char* key, 160 uint64_t major_version, 161 uint64_t minor_version) { 162 char major_digits[AVB_MAX_DIGITS_UINT64]; 163 char minor_digits[AVB_MAX_DIGITS_UINT64]; 164 char combined[AVB_MAX_DIGITS_UINT64 * 2 + 1]; 165 size_t num_major_digits, num_minor_digits; 166 167 num_major_digits = uint64_to_base10(major_version, major_digits); 168 num_minor_digits = uint64_to_base10(minor_version, minor_digits); 169 avb_memcpy(combined, major_digits, num_major_digits); 170 combined[num_major_digits] = '.'; 171 avb_memcpy(combined + num_major_digits + 1, minor_digits, num_minor_digits); 172 combined[num_major_digits + 1 + num_minor_digits] = '\0'; 173 174 return cmdline_append_option(slot_data, key, combined); 175 } 176 177 static int cmdline_append_uint64_base10(AvbSlotVerifyData* slot_data, 178 const char* key, 179 uint64_t value) { 180 char digits[AVB_MAX_DIGITS_UINT64]; 181 uint64_to_base10(value, digits); 182 return cmdline_append_option(slot_data, key, digits); 183 } 184 185 static int cmdline_append_hex(AvbSlotVerifyData* slot_data, 186 const char* key, 187 const uint8_t* data, 188 size_t data_len) { 189 int ret; 190 char* hex_data = avb_bin2hex(data, data_len); 191 if (hex_data == NULL) { 192 return 0; 193 } 194 ret = cmdline_append_option(slot_data, key, hex_data); 195 avb_free(hex_data); 196 return ret; 197 } 198 199 AvbSlotVerifyResult avb_append_options( 200 AvbOps* ops, 201 AvbSlotVerifyData* slot_data, 202 AvbVBMetaImageHeader* toplevel_vbmeta, 203 AvbAlgorithmType algorithm_type, 204 AvbHashtreeErrorMode hashtree_error_mode) { 205 AvbSlotVerifyResult ret; 206 const char* verity_mode; 207 bool is_device_unlocked; 208 AvbIOResult io_ret; 209 210 /* Add androidboot.vbmeta.device option. */ 211 if (!cmdline_append_option(slot_data, 212 "androidboot.vbmeta.device", 213 "PARTUUID=$(ANDROID_VBMETA_PARTUUID)")) { 214 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM; 215 goto out; 216 } 217 218 /* Add androidboot.vbmeta.avb_version option. */ 219 if (!cmdline_append_version(slot_data, 220 "androidboot.vbmeta.avb_version", 221 AVB_VERSION_MAJOR, 222 AVB_VERSION_MINOR)) { 223 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM; 224 goto out; 225 } 226 227 /* Set androidboot.avb.device_state to "locked" or "unlocked". */ 228 io_ret = ops->read_is_device_unlocked(ops, &is_device_unlocked); 229 if (io_ret == AVB_IO_RESULT_ERROR_OOM) { 230 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM; 231 goto out; 232 } else if (io_ret != AVB_IO_RESULT_OK) { 233 avb_error("Error getting device state.\n"); 234 ret = AVB_SLOT_VERIFY_RESULT_ERROR_IO; 235 goto out; 236 } 237 if (!cmdline_append_option(slot_data, 238 "androidboot.vbmeta.device_state", 239 is_device_unlocked ? "unlocked" : "locked")) { 240 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM; 241 goto out; 242 } 243 244 /* Set androidboot.vbmeta.{hash_alg, size, digest} - use same hash 245 * function as is used to sign vbmeta. 246 */ 247 switch (algorithm_type) { 248 /* Explicit fallthrough. */ 249 case AVB_ALGORITHM_TYPE_NONE: 250 case AVB_ALGORITHM_TYPE_SHA256_RSA2048: 251 case AVB_ALGORITHM_TYPE_SHA256_RSA4096: 252 case AVB_ALGORITHM_TYPE_SHA256_RSA8192: { 253 size_t n, total_size = 0; 254 uint8_t vbmeta_digest[AVB_SHA256_DIGEST_SIZE]; 255 avb_slot_verify_data_calculate_vbmeta_digest( 256 slot_data, AVB_DIGEST_TYPE_SHA256, vbmeta_digest); 257 for (n = 0; n < slot_data->num_vbmeta_images; n++) { 258 total_size += slot_data->vbmeta_images[n].vbmeta_size; 259 } 260 if (!cmdline_append_option( 261 slot_data, "androidboot.vbmeta.hash_alg", "sha256") || 262 !cmdline_append_uint64_base10( 263 slot_data, "androidboot.vbmeta.size", total_size) || 264 !cmdline_append_hex(slot_data, 265 "androidboot.vbmeta.digest", 266 vbmeta_digest, 267 AVB_SHA256_DIGEST_SIZE)) { 268 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM; 269 goto out; 270 } 271 } break; 272 /* Explicit fallthrough. */ 273 case AVB_ALGORITHM_TYPE_SHA512_RSA2048: 274 case AVB_ALGORITHM_TYPE_SHA512_RSA4096: 275 case AVB_ALGORITHM_TYPE_SHA512_RSA8192: { 276 size_t n, total_size = 0; 277 uint8_t vbmeta_digest[AVB_SHA512_DIGEST_SIZE]; 278 avb_slot_verify_data_calculate_vbmeta_digest( 279 slot_data, AVB_DIGEST_TYPE_SHA512, vbmeta_digest); 280 for (n = 0; n < slot_data->num_vbmeta_images; n++) { 281 total_size += slot_data->vbmeta_images[n].vbmeta_size; 282 } 283 if (!cmdline_append_option( 284 slot_data, "androidboot.vbmeta.hash_alg", "sha512") || 285 !cmdline_append_uint64_base10( 286 slot_data, "androidboot.vbmeta.size", total_size) || 287 !cmdline_append_hex(slot_data, 288 "androidboot.vbmeta.digest", 289 vbmeta_digest, 290 AVB_SHA512_DIGEST_SIZE)) { 291 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM; 292 goto out; 293 } 294 } break; 295 case _AVB_ALGORITHM_NUM_TYPES: 296 avb_assert_not_reached(); 297 break; 298 } 299 300 /* Set androidboot.veritymode and androidboot.vbmeta.invalidate_on_error */ 301 if (toplevel_vbmeta->flags & AVB_VBMETA_IMAGE_FLAGS_HASHTREE_DISABLED) { 302 verity_mode = "disabled"; 303 } else { 304 const char* dm_verity_mode; 305 char* new_ret; 306 307 switch (hashtree_error_mode) { 308 case AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE: 309 if (!cmdline_append_option( 310 slot_data, "androidboot.vbmeta.invalidate_on_error", "yes")) { 311 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM; 312 goto out; 313 } 314 verity_mode = "enforcing"; 315 dm_verity_mode = "restart_on_corruption"; 316 break; 317 case AVB_HASHTREE_ERROR_MODE_RESTART: 318 verity_mode = "enforcing"; 319 dm_verity_mode = "restart_on_corruption"; 320 break; 321 case AVB_HASHTREE_ERROR_MODE_EIO: 322 verity_mode = "eio"; 323 /* For now there's no option to specify the EIO mode. So 324 * just use 'ignore_zero_blocks' since that's already set 325 * and dm-verity-target.c supports specifying this multiple 326 * times. 327 */ 328 dm_verity_mode = "ignore_zero_blocks"; 329 break; 330 case AVB_HASHTREE_ERROR_MODE_LOGGING: 331 verity_mode = "logging"; 332 dm_verity_mode = "ignore_corruption"; 333 break; 334 default: 335 ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT; 336 goto out; 337 } 338 new_ret = avb_replace( 339 slot_data->cmdline, "$(ANDROID_VERITY_MODE)", dm_verity_mode); 340 avb_free(slot_data->cmdline); 341 slot_data->cmdline = new_ret; 342 if (slot_data->cmdline == NULL) { 343 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM; 344 goto out; 345 } 346 } 347 if (!cmdline_append_option( 348 slot_data, "androidboot.veritymode", verity_mode)) { 349 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM; 350 goto out; 351 } 352 353 ret = AVB_SLOT_VERIFY_RESULT_OK; 354 355 out: 356 357 return ret; 358 } 359 360 AvbCmdlineSubstList* avb_new_cmdline_subst_list() { 361 return (AvbCmdlineSubstList*)avb_calloc(sizeof(AvbCmdlineSubstList)); 362 } 363 364 void avb_free_cmdline_subst_list(AvbCmdlineSubstList* cmdline_subst) { 365 size_t i; 366 for (i = 0; i < cmdline_subst->size; ++i) { 367 avb_free(cmdline_subst->tokens[i]); 368 avb_free(cmdline_subst->values[i]); 369 } 370 cmdline_subst->size = 0; 371 avb_free(cmdline_subst); 372 } 373 374 AvbSlotVerifyResult avb_add_root_digest_substitution( 375 const char* part_name, 376 const uint8_t* digest, 377 size_t digest_size, 378 AvbCmdlineSubstList* out_cmdline_subst) { 379 const char* kDigestSubPrefix = "$(AVB_"; 380 const char* kDigestSubSuffix = "_ROOT_DIGEST)"; 381 size_t part_name_len = avb_strlen(part_name); 382 size_t list_index = out_cmdline_subst->size; 383 384 avb_assert(part_name_len < AVB_PART_NAME_MAX_SIZE); 385 avb_assert(digest_size <= AVB_SHA512_DIGEST_SIZE); 386 if (part_name_len >= AVB_PART_NAME_MAX_SIZE || 387 digest_size > AVB_SHA512_DIGEST_SIZE) { 388 return AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA; 389 } 390 391 if (out_cmdline_subst->size >= AVB_MAX_NUM_CMDLINE_SUBST) { 392 /* The list is full. Currently dynamic growth of this list is not supported. 393 */ 394 return AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA; 395 } 396 397 /* Construct the token to replace in the command line based on the partition 398 * name. For partition 'foo', this will be '$(AVB_FOO_ROOT_DIGEST)'. 399 */ 400 out_cmdline_subst->tokens[list_index] = 401 avb_strdupv(kDigestSubPrefix, part_name, kDigestSubSuffix, NULL); 402 if (out_cmdline_subst->tokens[list_index] == NULL) { 403 goto fail; 404 } 405 avb_uppercase(out_cmdline_subst->tokens[list_index]); 406 407 /* The digest value is hex encoded when inserted in the command line. */ 408 out_cmdline_subst->values[list_index] = avb_bin2hex(digest, digest_size); 409 if (out_cmdline_subst->values[list_index] == NULL) { 410 goto fail; 411 } 412 413 out_cmdline_subst->size++; 414 return AVB_SLOT_VERIFY_RESULT_OK; 415 416 fail: 417 if (out_cmdline_subst->tokens[list_index]) { 418 avb_free(out_cmdline_subst->tokens[list_index]); 419 } 420 if (out_cmdline_subst->values[list_index]) { 421 avb_free(out_cmdline_subst->values[list_index]); 422 } 423 return AVB_SLOT_VERIFY_RESULT_ERROR_OOM; 424 } 425