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 #include <android_avb/avb_cmdline.h> 26 #include <android_avb/avb_sha.h> 27 #include <android_avb/avb_util.h> 28 #include <android_avb/avb_version.h> 29 30 #define NUM_GUIDS 3 31 32 /* Substitutes all variables (e.g. $(ANDROID_SYSTEM_PARTUUID)) with 33 * values. Returns NULL on OOM, otherwise the cmdline with values 34 * replaced. 35 */ 36 char* avb_sub_cmdline(AvbOps* ops, const char* cmdline, const char* ab_suffix, 37 bool using_boot_for_vbmeta) { 38 const char* part_name_str[NUM_GUIDS] = {"system", "boot", "vbmeta"}; 39 const char* replace_str[NUM_GUIDS] = {"$(ANDROID_SYSTEM_PARTUUID)", 40 "$(ANDROID_BOOT_PARTUUID)", 41 "$(ANDROID_VBMETA_PARTUUID)"}; 42 char* ret = NULL; 43 AvbIOResult io_ret; 44 size_t n; 45 46 /* Special-case for when the top-level vbmeta struct is in the boot 47 * partition. 48 */ 49 if (using_boot_for_vbmeta) { 50 part_name_str[2] = "boot"; 51 } 52 53 /* Replace unique partition GUIDs */ 54 for (n = 0; n < NUM_GUIDS; n++) { 55 char part_name[AVB_PART_NAME_MAX_SIZE]; 56 char guid_buf[37]; 57 58 if (!avb_str_concat(part_name, 59 sizeof part_name, 60 part_name_str[n], 61 avb_strlen(part_name_str[n]), 62 ab_suffix, 63 avb_strlen(ab_suffix))) { 64 avb_error("Partition name and suffix does not fit.\n"); 65 goto fail; 66 } 67 68 io_ret = ops->get_unique_guid_for_partition( 69 ops, part_name, guid_buf, sizeof guid_buf); 70 if (io_ret == AVB_IO_RESULT_ERROR_OOM) { 71 return NULL; 72 } else if (io_ret != AVB_IO_RESULT_OK) { 73 avb_error("Error getting unique GUID for partition.\n"); 74 goto fail; 75 } 76 77 if (ret == NULL) { 78 ret = avb_replace(cmdline, replace_str[n], guid_buf); 79 } else { 80 char* new_ret = avb_replace(ret, replace_str[n], guid_buf); 81 avb_free(ret); 82 ret = new_ret; 83 } 84 if (ret == NULL) { 85 goto fail; 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 char hex_digits[17] = "0123456789abcdef"; 190 char* hex_data; 191 int ret; 192 size_t n; 193 194 hex_data = avb_malloc(data_len * 2 + 1); 195 if (hex_data == NULL) { 196 return 0; 197 } 198 199 for (n = 0; n < data_len; n++) { 200 hex_data[n * 2] = hex_digits[data[n] >> 4]; 201 hex_data[n * 2 + 1] = hex_digits[data[n] & 0x0f]; 202 } 203 hex_data[n * 2] = '\0'; 204 205 ret = cmdline_append_option(slot_data, key, hex_data); 206 avb_free(hex_data); 207 return ret; 208 } 209 210 AvbSlotVerifyResult avb_append_options( 211 AvbOps* ops, 212 AvbSlotVerifyData* slot_data, 213 AvbVBMetaImageHeader* toplevel_vbmeta, 214 AvbAlgorithmType algorithm_type, 215 AvbHashtreeErrorMode hashtree_error_mode) { 216 AvbSlotVerifyResult ret; 217 const char* verity_mode = NULL; 218 bool is_device_unlocked; 219 AvbIOResult io_ret; 220 221 /* Add androidboot.vbmeta.device option. */ 222 if (!cmdline_append_option(slot_data, 223 "androidboot.vbmeta.device", 224 "PARTUUID=$(ANDROID_VBMETA_PARTUUID)")) { 225 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM; 226 goto out; 227 } 228 229 /* Add androidboot.vbmeta.avb_version option. */ 230 if (!cmdline_append_version(slot_data, 231 "androidboot.vbmeta.avb_version", 232 AVB_VERSION_MAJOR, 233 AVB_VERSION_MINOR)) { 234 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM; 235 goto out; 236 } 237 238 /* Set androidboot.avb.device_state to "locked" or "unlocked". */ 239 io_ret = ops->read_is_device_unlocked(ops, &is_device_unlocked); 240 if (io_ret == AVB_IO_RESULT_ERROR_OOM) { 241 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM; 242 goto out; 243 } else if (io_ret != AVB_IO_RESULT_OK) { 244 avb_error("Error getting device state.\n"); 245 ret = AVB_SLOT_VERIFY_RESULT_ERROR_IO; 246 goto out; 247 } 248 if (!cmdline_append_option(slot_data, 249 "androidboot.vbmeta.device_state", 250 is_device_unlocked ? "unlocked" : "locked")) { 251 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM; 252 goto out; 253 } 254 255 /* Set androidboot.vbmeta.{hash_alg, size, digest} - use same hash 256 * function as is used to sign vbmeta. 257 */ 258 switch (algorithm_type) { 259 /* Explicit fallthrough. */ 260 case AVB_ALGORITHM_TYPE_NONE: 261 case AVB_ALGORITHM_TYPE_SHA256_RSA2048: 262 case AVB_ALGORITHM_TYPE_SHA256_RSA4096: 263 case AVB_ALGORITHM_TYPE_SHA256_RSA8192: { 264 AvbSHA256Ctx ctx; 265 size_t n, total_size = 0; 266 avb_sha256_init(&ctx); 267 for (n = 0; n < slot_data->num_vbmeta_images; n++) { 268 avb_sha256_update(&ctx, 269 slot_data->vbmeta_images[n].vbmeta_data, 270 slot_data->vbmeta_images[n].vbmeta_size); 271 total_size += slot_data->vbmeta_images[n].vbmeta_size; 272 } 273 if (!cmdline_append_option( 274 slot_data, "androidboot.vbmeta.hash_alg", "sha256") || 275 !cmdline_append_uint64_base10( 276 slot_data, "androidboot.vbmeta.size", total_size) || 277 !cmdline_append_hex(slot_data, 278 "androidboot.vbmeta.digest", 279 avb_sha256_final(&ctx), 280 AVB_SHA256_DIGEST_SIZE)) { 281 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM; 282 goto out; 283 } 284 } break; 285 /* Explicit fallthrough. */ 286 case AVB_ALGORITHM_TYPE_SHA512_RSA2048: 287 case AVB_ALGORITHM_TYPE_SHA512_RSA4096: 288 case AVB_ALGORITHM_TYPE_SHA512_RSA8192: { 289 AvbSHA512Ctx ctx; 290 size_t n, total_size = 0; 291 avb_sha512_init(&ctx); 292 for (n = 0; n < slot_data->num_vbmeta_images; n++) { 293 avb_sha512_update(&ctx, 294 slot_data->vbmeta_images[n].vbmeta_data, 295 slot_data->vbmeta_images[n].vbmeta_size); 296 total_size += slot_data->vbmeta_images[n].vbmeta_size; 297 } 298 if (!cmdline_append_option( 299 slot_data, "androidboot.vbmeta.hash_alg", "sha512") || 300 !cmdline_append_uint64_base10( 301 slot_data, "androidboot.vbmeta.size", total_size) || 302 !cmdline_append_hex(slot_data, 303 "androidboot.vbmeta.digest", 304 avb_sha512_final(&ctx), 305 AVB_SHA512_DIGEST_SIZE)) { 306 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM; 307 goto out; 308 } 309 } break; 310 case _AVB_ALGORITHM_NUM_TYPES: 311 avb_assert_not_reached(); 312 break; 313 } 314 315 /* Set androidboot.veritymode and androidboot.vbmeta.invalidate_on_error */ 316 if (toplevel_vbmeta->flags & AVB_VBMETA_IMAGE_FLAGS_HASHTREE_DISABLED) { 317 verity_mode = "disabled"; 318 } else { 319 const char* dm_verity_mode = NULL; 320 char* new_ret; 321 322 switch (hashtree_error_mode) { 323 case AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE: 324 if (!cmdline_append_option( 325 slot_data, "androidboot.vbmeta.invalidate_on_error", "yes")) { 326 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM; 327 goto out; 328 } 329 verity_mode = "enforcing"; 330 dm_verity_mode = "restart_on_corruption"; 331 break; 332 case AVB_HASHTREE_ERROR_MODE_RESTART: 333 verity_mode = "enforcing"; 334 dm_verity_mode = "restart_on_corruption"; 335 break; 336 case AVB_HASHTREE_ERROR_MODE_EIO: 337 verity_mode = "eio"; 338 /* For now there's no option to specify the EIO mode. So 339 * just use 'ignore_zero_blocks' since that's already set 340 * and dm-verity-target.c supports specifying this multiple 341 * times. 342 */ 343 dm_verity_mode = "ignore_zero_blocks"; 344 break; 345 case AVB_HASHTREE_ERROR_MODE_LOGGING: 346 verity_mode = "logging"; 347 dm_verity_mode = "ignore_corruption"; 348 break; 349 } 350 new_ret = avb_replace( 351 slot_data->cmdline, "$(ANDROID_VERITY_MODE)", dm_verity_mode); 352 avb_free(slot_data->cmdline); 353 slot_data->cmdline = new_ret; 354 if (slot_data->cmdline == NULL) { 355 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM; 356 goto out; 357 } 358 } 359 if (!cmdline_append_option( 360 slot_data, "androidboot.veritymode", verity_mode)) { 361 ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM; 362 goto out; 363 } 364 365 ret = AVB_SLOT_VERIFY_RESULT_OK; 366 367 out: 368 369 return ret; 370 } 371 372