1 /* 2 * Copyright (C) 2015 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include "Ext4Crypt.h" 18 19 #include "KeyStorage.h" 20 #include "Utils.h" 21 22 #include <algorithm> 23 #include <iomanip> 24 #include <map> 25 #include <set> 26 #include <sstream> 27 #include <string> 28 29 #include <dirent.h> 30 #include <errno.h> 31 #include <fcntl.h> 32 #include <limits.h> 33 #include <openssl/sha.h> 34 #include <selinux/android.h> 35 #include <stdio.h> 36 #include <sys/mount.h> 37 #include <sys/stat.h> 38 #include <sys/types.h> 39 40 #include <private/android_filesystem_config.h> 41 42 #include "cryptfs.h" 43 44 #define EMULATED_USES_SELINUX 0 45 #define MANAGE_MISC_DIRS 0 46 47 #include <cutils/fs.h> 48 #include <ext4_utils/ext4_crypt.h> 49 #include <ext4_utils/key_control.h> 50 51 #include <android-base/file.h> 52 #include <android-base/logging.h> 53 #include <android-base/stringprintf.h> 54 55 using android::base::StringPrintf; 56 using android::vold::kEmptyAuthentication; 57 58 // NOTE: keep in sync with StorageManager 59 static constexpr int FLAG_STORAGE_DE = 1 << 0; 60 static constexpr int FLAG_STORAGE_CE = 1 << 1; 61 62 namespace { 63 64 const std::string device_key_dir = std::string() + DATA_MNT_POINT + e4crypt_unencrypted_folder; 65 const std::string device_key_path = device_key_dir + "/key"; 66 const std::string device_key_temp = device_key_dir + "/temp"; 67 68 const std::string user_key_dir = std::string() + DATA_MNT_POINT + "/misc/vold/user_keys"; 69 const std::string user_key_temp = user_key_dir + "/temp"; 70 71 bool s_global_de_initialized = false; 72 73 // Some users are ephemeral, don't try to wipe their keys from disk 74 std::set<userid_t> s_ephemeral_users; 75 76 // Map user ids to key references 77 std::map<userid_t, std::string> s_de_key_raw_refs; 78 std::map<userid_t, std::string> s_ce_key_raw_refs; 79 // TODO abolish this map, per b/26948053 80 std::map<userid_t, std::string> s_ce_keys; 81 82 // ext4enc:TODO get this const from somewhere good 83 const int EXT4_KEY_DESCRIPTOR_SIZE = 8; 84 85 // ext4enc:TODO Include structure from somewhere sensible 86 // MUST be in sync with ext4_crypto.c in kernel 87 constexpr int EXT4_ENCRYPTION_MODE_AES_256_XTS = 1; 88 constexpr int EXT4_AES_256_XTS_KEY_SIZE = 64; 89 constexpr int EXT4_MAX_KEY_SIZE = 64; 90 struct ext4_encryption_key { 91 uint32_t mode; 92 char raw[EXT4_MAX_KEY_SIZE]; 93 uint32_t size; 94 }; 95 } 96 97 static bool e4crypt_is_emulated() { 98 return property_get_bool("persist.sys.emulate_fbe", false); 99 } 100 101 static const char* escape_null(const char* value) { 102 return (value == nullptr) ? "null" : value; 103 } 104 105 // Get raw keyref - used to make keyname and to pass to ioctl 106 static std::string generate_key_ref(const char* key, int length) { 107 SHA512_CTX c; 108 109 SHA512_Init(&c); 110 SHA512_Update(&c, key, length); 111 unsigned char key_ref1[SHA512_DIGEST_LENGTH]; 112 SHA512_Final(key_ref1, &c); 113 114 SHA512_Init(&c); 115 SHA512_Update(&c, key_ref1, SHA512_DIGEST_LENGTH); 116 unsigned char key_ref2[SHA512_DIGEST_LENGTH]; 117 SHA512_Final(key_ref2, &c); 118 119 static_assert(EXT4_KEY_DESCRIPTOR_SIZE <= SHA512_DIGEST_LENGTH, 120 "Hash too short for descriptor"); 121 return std::string((char*)key_ref2, EXT4_KEY_DESCRIPTOR_SIZE); 122 } 123 124 static bool fill_key(const std::string& key, ext4_encryption_key* ext4_key) { 125 if (key.size() != EXT4_AES_256_XTS_KEY_SIZE) { 126 LOG(ERROR) << "Wrong size key " << key.size(); 127 return false; 128 } 129 static_assert(EXT4_AES_256_XTS_KEY_SIZE <= sizeof(ext4_key->raw), "Key too long!"); 130 ext4_key->mode = EXT4_ENCRYPTION_MODE_AES_256_XTS; 131 ext4_key->size = key.size(); 132 memset(ext4_key->raw, 0, sizeof(ext4_key->raw)); 133 memcpy(ext4_key->raw, key.data(), key.size()); 134 return true; 135 } 136 137 static std::string keyname(const std::string& raw_ref) { 138 std::ostringstream o; 139 o << "ext4:"; 140 for (unsigned char i : raw_ref) { 141 o << std::hex << std::setw(2) << std::setfill('0') << (int)i; 142 } 143 return o.str(); 144 } 145 146 // Get the keyring we store all keys in 147 static bool e4crypt_keyring(key_serial_t* device_keyring) { 148 *device_keyring = keyctl_search(KEY_SPEC_SESSION_KEYRING, "keyring", "e4crypt", 0); 149 if (*device_keyring == -1) { 150 PLOG(ERROR) << "Unable to find device keyring"; 151 return false; 152 } 153 return true; 154 } 155 156 // Install password into global keyring 157 // Return raw key reference for use in policy 158 static bool install_key(const std::string& key, std::string* raw_ref) { 159 ext4_encryption_key ext4_key; 160 if (!fill_key(key, &ext4_key)) return false; 161 *raw_ref = generate_key_ref(ext4_key.raw, ext4_key.size); 162 auto ref = keyname(*raw_ref); 163 key_serial_t device_keyring; 164 if (!e4crypt_keyring(&device_keyring)) return false; 165 key_serial_t key_id = 166 add_key("logon", ref.c_str(), (void*)&ext4_key, sizeof(ext4_key), device_keyring); 167 if (key_id == -1) { 168 PLOG(ERROR) << "Failed to insert key into keyring " << device_keyring; 169 return false; 170 } 171 LOG(DEBUG) << "Added key " << key_id << " (" << ref << ") to keyring " << device_keyring 172 << " in process " << getpid(); 173 174 return true; 175 } 176 177 static std::string get_de_key_path(userid_t user_id) { 178 return StringPrintf("%s/de/%d", user_key_dir.c_str(), user_id); 179 } 180 181 static std::string get_ce_key_directory_path(userid_t user_id) { 182 return StringPrintf("%s/ce/%d", user_key_dir.c_str(), user_id); 183 } 184 185 // Returns the keys newest first 186 static std::vector<std::string> get_ce_key_paths(const std::string& directory_path) { 187 auto dirp = std::unique_ptr<DIR, int (*)(DIR*)>(opendir(directory_path.c_str()), closedir); 188 if (!dirp) { 189 PLOG(ERROR) << "Unable to open ce key directory: " + directory_path; 190 return std::vector<std::string>(); 191 } 192 std::vector<std::string> result; 193 for (;;) { 194 errno = 0; 195 auto const entry = readdir(dirp.get()); 196 if (!entry) { 197 if (errno) { 198 PLOG(ERROR) << "Unable to read ce key directory: " + directory_path; 199 return std::vector<std::string>(); 200 } 201 break; 202 } 203 if (entry->d_type != DT_DIR || entry->d_name[0] != 'c') { 204 LOG(DEBUG) << "Skipping non-key " << entry->d_name; 205 continue; 206 } 207 result.emplace_back(directory_path + "/" + entry->d_name); 208 } 209 std::sort(result.begin(), result.end()); 210 std::reverse(result.begin(), result.end()); 211 return result; 212 } 213 214 static std::string get_ce_key_current_path(const std::string& directory_path) { 215 return directory_path + "/current"; 216 } 217 218 static bool get_ce_key_new_path(const std::string& directory_path, 219 const std::vector<std::string>& paths, 220 std::string *ce_key_path) { 221 if (paths.empty()) { 222 *ce_key_path = get_ce_key_current_path(directory_path); 223 return true; 224 } 225 for (unsigned int i = 0; i < UINT_MAX; i++) { 226 auto const candidate = StringPrintf("%s/cx%010u", directory_path.c_str(), i); 227 if (paths[0] < candidate) { 228 *ce_key_path = candidate; 229 return true; 230 } 231 } 232 return false; 233 } 234 235 // Discard all keys but the named one; rename it to canonical name. 236 // No point in acting on errors in this; ignore them. 237 static void fixate_user_ce_key(const std::string& directory_path, const std::string &to_fix, 238 const std::vector<std::string>& paths) { 239 for (auto const other_path: paths) { 240 if (other_path != to_fix) { 241 android::vold::destroyKey(other_path); 242 } 243 } 244 auto const current_path = get_ce_key_current_path(directory_path); 245 if (to_fix != current_path) { 246 LOG(DEBUG) << "Renaming " << to_fix << " to " << current_path; 247 if (rename(to_fix.c_str(), current_path.c_str()) != 0) { 248 PLOG(WARNING) << "Unable to rename " << to_fix << " to " << current_path; 249 } 250 } 251 } 252 253 static bool read_and_fixate_user_ce_key(userid_t user_id, 254 const android::vold::KeyAuthentication& auth, 255 std::string *ce_key) { 256 auto const directory_path = get_ce_key_directory_path(user_id); 257 auto const paths = get_ce_key_paths(directory_path); 258 for (auto const ce_key_path: paths) { 259 LOG(DEBUG) << "Trying user CE key " << ce_key_path; 260 if (android::vold::retrieveKey(ce_key_path, auth, ce_key)) { 261 LOG(DEBUG) << "Successfully retrieved key"; 262 fixate_user_ce_key(directory_path, ce_key_path, paths); 263 return true; 264 } 265 } 266 LOG(ERROR) << "Failed to find working ce key for user " << user_id; 267 return false; 268 } 269 270 static bool read_and_install_user_ce_key(userid_t user_id, 271 const android::vold::KeyAuthentication& auth) { 272 if (s_ce_key_raw_refs.count(user_id) != 0) return true; 273 std::string ce_key; 274 if (!read_and_fixate_user_ce_key(user_id, auth, &ce_key)) return false; 275 std::string ce_raw_ref; 276 if (!install_key(ce_key, &ce_raw_ref)) return false; 277 s_ce_keys[user_id] = ce_key; 278 s_ce_key_raw_refs[user_id] = ce_raw_ref; 279 LOG(DEBUG) << "Installed ce key for user " << user_id; 280 return true; 281 } 282 283 static bool prepare_dir(const std::string& dir, mode_t mode, uid_t uid, gid_t gid) { 284 LOG(DEBUG) << "Preparing: " << dir; 285 if (fs_prepare_dir(dir.c_str(), mode, uid, gid) != 0) { 286 PLOG(ERROR) << "Failed to prepare " << dir; 287 return false; 288 } 289 return true; 290 } 291 292 static bool destroy_dir(const std::string& dir) { 293 LOG(DEBUG) << "Destroying: " << dir; 294 if (rmdir(dir.c_str()) != 0 && errno != ENOENT) { 295 PLOG(ERROR) << "Failed to destroy " << dir; 296 return false; 297 } 298 return true; 299 } 300 301 static bool random_key(std::string* key) { 302 if (android::vold::ReadRandomBytes(EXT4_AES_256_XTS_KEY_SIZE, *key) != 0) { 303 // TODO status_t plays badly with PLOG, fix it. 304 LOG(ERROR) << "Random read failed"; 305 return false; 306 } 307 return true; 308 } 309 310 static bool path_exists(const std::string& path) { 311 return access(path.c_str(), F_OK) == 0; 312 } 313 314 // NB this assumes that there is only one thread listening for crypt commands, because 315 // it creates keys in a fixed location. 316 static bool store_key(const std::string& key_path, const std::string& tmp_path, 317 const android::vold::KeyAuthentication& auth, const std::string& key) { 318 if (path_exists(key_path)) { 319 LOG(ERROR) << "Already exists, cannot create key at: " << key_path; 320 return false; 321 } 322 if (path_exists(tmp_path)) { 323 android::vold::destroyKey(tmp_path); // May be partially created so ignore errors 324 } 325 if (!android::vold::storeKey(tmp_path, auth, key)) return false; 326 if (rename(tmp_path.c_str(), key_path.c_str()) != 0) { 327 PLOG(ERROR) << "Unable to move new key to location: " << key_path; 328 return false; 329 } 330 LOG(DEBUG) << "Created key " << key_path; 331 return true; 332 } 333 334 static bool create_and_install_user_keys(userid_t user_id, bool create_ephemeral) { 335 std::string de_key, ce_key; 336 if (!random_key(&de_key)) return false; 337 if (!random_key(&ce_key)) return false; 338 if (create_ephemeral) { 339 // If the key should be created as ephemeral, don't store it. 340 s_ephemeral_users.insert(user_id); 341 } else { 342 auto const directory_path = get_ce_key_directory_path(user_id); 343 if (!prepare_dir(directory_path, 0700, AID_ROOT, AID_ROOT)) return false; 344 auto const paths = get_ce_key_paths(directory_path); 345 std::string ce_key_path; 346 if (!get_ce_key_new_path(directory_path, paths, &ce_key_path)) return false; 347 if (!store_key(ce_key_path, user_key_temp, 348 kEmptyAuthentication, ce_key)) return false; 349 fixate_user_ce_key(directory_path, ce_key_path, paths); 350 // Write DE key second; once this is written, all is good. 351 if (!store_key(get_de_key_path(user_id), user_key_temp, 352 kEmptyAuthentication, de_key)) return false; 353 } 354 std::string de_raw_ref; 355 if (!install_key(de_key, &de_raw_ref)) return false; 356 s_de_key_raw_refs[user_id] = de_raw_ref; 357 std::string ce_raw_ref; 358 if (!install_key(ce_key, &ce_raw_ref)) return false; 359 s_ce_keys[user_id] = ce_key; 360 s_ce_key_raw_refs[user_id] = ce_raw_ref; 361 LOG(DEBUG) << "Created keys for user " << user_id; 362 return true; 363 } 364 365 static bool lookup_key_ref(const std::map<userid_t, std::string>& key_map, userid_t user_id, 366 std::string* raw_ref) { 367 auto refi = key_map.find(user_id); 368 if (refi == key_map.end()) { 369 LOG(ERROR) << "Cannot find key for " << user_id; 370 return false; 371 } 372 *raw_ref = refi->second; 373 return true; 374 } 375 376 static bool ensure_policy(const std::string& raw_ref, const std::string& path) { 377 const char *contents_mode; 378 const char *filenames_mode; 379 380 cryptfs_get_file_encryption_modes(&contents_mode, &filenames_mode); 381 382 if (e4crypt_policy_ensure(path.c_str(), 383 raw_ref.data(), raw_ref.size(), 384 contents_mode, filenames_mode) != 0) { 385 LOG(ERROR) << "Failed to set policy on: " << path; 386 return false; 387 } 388 return true; 389 } 390 391 static bool is_numeric(const char* name) { 392 for (const char* p = name; *p != '\0'; p++) { 393 if (!isdigit(*p)) return false; 394 } 395 return true; 396 } 397 398 static bool load_all_de_keys() { 399 auto de_dir = user_key_dir + "/de"; 400 auto dirp = std::unique_ptr<DIR, int (*)(DIR*)>(opendir(de_dir.c_str()), closedir); 401 if (!dirp) { 402 PLOG(ERROR) << "Unable to read de key directory"; 403 return false; 404 } 405 for (;;) { 406 errno = 0; 407 auto entry = readdir(dirp.get()); 408 if (!entry) { 409 if (errno) { 410 PLOG(ERROR) << "Unable to read de key directory"; 411 return false; 412 } 413 break; 414 } 415 if (entry->d_type != DT_DIR || !is_numeric(entry->d_name)) { 416 LOG(DEBUG) << "Skipping non-de-key " << entry->d_name; 417 continue; 418 } 419 userid_t user_id = atoi(entry->d_name); 420 if (s_de_key_raw_refs.count(user_id) == 0) { 421 auto key_path = de_dir + "/" + entry->d_name; 422 std::string key; 423 if (!android::vold::retrieveKey(key_path, kEmptyAuthentication, &key)) return false; 424 std::string raw_ref; 425 if (!install_key(key, &raw_ref)) return false; 426 s_de_key_raw_refs[user_id] = raw_ref; 427 LOG(DEBUG) << "Installed de key for user " << user_id; 428 } 429 } 430 // ext4enc:TODO: go through all DE directories, ensure that all user dirs have the 431 // correct policy set on them, and that no rogue ones exist. 432 return true; 433 } 434 435 bool e4crypt_initialize_global_de() { 436 LOG(INFO) << "e4crypt_initialize_global_de"; 437 438 if (s_global_de_initialized) { 439 LOG(INFO) << "Already initialized"; 440 return true; 441 } 442 443 const char *contents_mode; 444 const char *filenames_mode; 445 cryptfs_get_file_encryption_modes(&contents_mode, &filenames_mode); 446 std::string modestring = std::string(contents_mode) + ":" + filenames_mode; 447 448 std::string mode_filename = std::string("/data") + e4crypt_key_mode; 449 if (!android::base::WriteStringToFile(modestring, mode_filename)) { 450 PLOG(ERROR) << "Cannot save type"; 451 return false; 452 } 453 454 std::string device_key; 455 if (path_exists(device_key_path)) { 456 if (!android::vold::retrieveKey(device_key_path, 457 kEmptyAuthentication, &device_key)) return false; 458 } else { 459 LOG(INFO) << "Creating new key"; 460 if (!random_key(&device_key)) return false; 461 if (!store_key(device_key_path, device_key_temp, 462 kEmptyAuthentication, device_key)) return false; 463 } 464 465 std::string device_key_ref; 466 if (!install_key(device_key, &device_key_ref)) { 467 LOG(ERROR) << "Failed to install device key"; 468 return false; 469 } 470 471 std::string ref_filename = std::string("/data") + e4crypt_key_ref; 472 if (!android::base::WriteStringToFile(device_key_ref, ref_filename)) { 473 PLOG(ERROR) << "Cannot save key reference"; 474 return false; 475 } 476 477 s_global_de_initialized = true; 478 return true; 479 } 480 481 bool e4crypt_init_user0() { 482 LOG(DEBUG) << "e4crypt_init_user0"; 483 if (e4crypt_is_native()) { 484 if (!prepare_dir(user_key_dir, 0700, AID_ROOT, AID_ROOT)) return false; 485 if (!prepare_dir(user_key_dir + "/ce", 0700, AID_ROOT, AID_ROOT)) return false; 486 if (!prepare_dir(user_key_dir + "/de", 0700, AID_ROOT, AID_ROOT)) return false; 487 if (!path_exists(get_de_key_path(0))) { 488 if (!create_and_install_user_keys(0, false)) return false; 489 } 490 // TODO: switch to loading only DE_0 here once framework makes 491 // explicit calls to install DE keys for secondary users 492 if (!load_all_de_keys()) return false; 493 } 494 // We can only safely prepare DE storage here, since CE keys are probably 495 // entangled with user credentials. The framework will always prepare CE 496 // storage once CE keys are installed. 497 if (!e4crypt_prepare_user_storage(nullptr, 0, 0, FLAG_STORAGE_DE)) { 498 LOG(ERROR) << "Failed to prepare user 0 storage"; 499 return false; 500 } 501 502 // If this is a non-FBE device that recently left an emulated mode, 503 // restore user data directories to known-good state. 504 if (!e4crypt_is_native() && !e4crypt_is_emulated()) { 505 e4crypt_unlock_user_key(0, 0, "!", "!"); 506 } 507 508 return true; 509 } 510 511 bool e4crypt_vold_create_user_key(userid_t user_id, int serial, bool ephemeral) { 512 LOG(DEBUG) << "e4crypt_vold_create_user_key for " << user_id << " serial " << serial; 513 if (!e4crypt_is_native()) { 514 return true; 515 } 516 // FIXME test for existence of key that is not loaded yet 517 if (s_ce_key_raw_refs.count(user_id) != 0) { 518 LOG(ERROR) << "Already exists, can't e4crypt_vold_create_user_key for " << user_id 519 << " serial " << serial; 520 // FIXME should we fail the command? 521 return true; 522 } 523 if (!create_and_install_user_keys(user_id, ephemeral)) { 524 return false; 525 } 526 return true; 527 } 528 529 static bool evict_key(const std::string &raw_ref) { 530 auto ref = keyname(raw_ref); 531 key_serial_t device_keyring; 532 if (!e4crypt_keyring(&device_keyring)) return false; 533 auto key_serial = keyctl_search(device_keyring, "logon", ref.c_str(), 0); 534 535 // Unlink the key from the keyring. Prefer unlinking to revoking or 536 // invalidating, since unlinking is actually no less secure currently, and 537 // it avoids bugs in certain kernel versions where the keyring key is 538 // referenced from places it shouldn't be. 539 if (keyctl_unlink(key_serial, device_keyring) != 0) { 540 PLOG(ERROR) << "Failed to unlink key with serial " << key_serial << " ref " << ref; 541 return false; 542 } 543 LOG(DEBUG) << "Unlinked key with serial " << key_serial << " ref " << ref; 544 return true; 545 } 546 547 static bool evict_ce_key(userid_t user_id) { 548 s_ce_keys.erase(user_id); 549 bool success = true; 550 std::string raw_ref; 551 // If we haven't loaded the CE key, no need to evict it. 552 if (lookup_key_ref(s_ce_key_raw_refs, user_id, &raw_ref)) { 553 success &= evict_key(raw_ref); 554 } 555 s_ce_key_raw_refs.erase(user_id); 556 return success; 557 } 558 559 bool e4crypt_destroy_user_key(userid_t user_id) { 560 LOG(DEBUG) << "e4crypt_destroy_user_key(" << user_id << ")"; 561 if (!e4crypt_is_native()) { 562 return true; 563 } 564 bool success = true; 565 std::string raw_ref; 566 success &= evict_ce_key(user_id); 567 success &= lookup_key_ref(s_de_key_raw_refs, user_id, &raw_ref) && evict_key(raw_ref); 568 s_de_key_raw_refs.erase(user_id); 569 auto it = s_ephemeral_users.find(user_id); 570 if (it != s_ephemeral_users.end()) { 571 s_ephemeral_users.erase(it); 572 } else { 573 for (auto const path: get_ce_key_paths(get_ce_key_directory_path(user_id))) { 574 success &= android::vold::destroyKey(path); 575 } 576 auto de_key_path = get_de_key_path(user_id); 577 if (path_exists(de_key_path)) { 578 success &= android::vold::destroyKey(de_key_path); 579 } else { 580 LOG(INFO) << "Not present so not erasing: " << de_key_path; 581 } 582 } 583 return success; 584 } 585 586 static bool emulated_lock(const std::string& path) { 587 if (chmod(path.c_str(), 0000) != 0) { 588 PLOG(ERROR) << "Failed to chmod " << path; 589 return false; 590 } 591 #if EMULATED_USES_SELINUX 592 if (setfilecon(path.c_str(), "u:object_r:storage_stub_file:s0") != 0) { 593 PLOG(WARNING) << "Failed to setfilecon " << path; 594 return false; 595 } 596 #endif 597 return true; 598 } 599 600 static bool emulated_unlock(const std::string& path, mode_t mode) { 601 if (chmod(path.c_str(), mode) != 0) { 602 PLOG(ERROR) << "Failed to chmod " << path; 603 // FIXME temporary workaround for b/26713622 604 if (e4crypt_is_emulated()) return false; 605 } 606 #if EMULATED_USES_SELINUX 607 if (selinux_android_restorecon(path.c_str(), SELINUX_ANDROID_RESTORECON_FORCE) != 0) { 608 PLOG(WARNING) << "Failed to restorecon " << path; 609 // FIXME temporary workaround for b/26713622 610 if (e4crypt_is_emulated()) return false; 611 } 612 #endif 613 return true; 614 } 615 616 static bool parse_hex(const char* hex, std::string* result) { 617 if (strcmp("!", hex) == 0) { 618 *result = ""; 619 return true; 620 } 621 if (android::vold::HexToStr(hex, *result) != 0) { 622 LOG(ERROR) << "Invalid FBE hex string"; // Don't log the string for security reasons 623 return false; 624 } 625 return true; 626 } 627 628 bool e4crypt_add_user_key_auth(userid_t user_id, int serial, const char* token_hex, 629 const char* secret_hex) { 630 LOG(DEBUG) << "e4crypt_add_user_key_auth " << user_id << " serial=" << serial 631 << " token_present=" << (strcmp(token_hex, "!") != 0); 632 if (!e4crypt_is_native()) return true; 633 if (s_ephemeral_users.count(user_id) != 0) return true; 634 std::string token, secret; 635 if (!parse_hex(token_hex, &token)) return false; 636 if (!parse_hex(secret_hex, &secret)) return false; 637 auto auth = secret.empty() ? kEmptyAuthentication 638 : android::vold::KeyAuthentication(token, secret); 639 auto it = s_ce_keys.find(user_id); 640 if (it == s_ce_keys.end()) { 641 LOG(ERROR) << "Key not loaded into memory, can't change for user " << user_id; 642 return false; 643 } 644 auto ce_key = it->second; 645 auto const directory_path = get_ce_key_directory_path(user_id); 646 auto const paths = get_ce_key_paths(directory_path); 647 std::string ce_key_path; 648 if (!get_ce_key_new_path(directory_path, paths, &ce_key_path)) return false; 649 if (!store_key(ce_key_path, user_key_temp, auth, ce_key)) return false; 650 return true; 651 } 652 653 bool e4crypt_fixate_newest_user_key_auth(userid_t user_id) { 654 LOG(DEBUG) << "e4crypt_fixate_newest_user_key_auth " << user_id; 655 if (!e4crypt_is_native()) return true; 656 if (s_ephemeral_users.count(user_id) != 0) return true; 657 auto const directory_path = get_ce_key_directory_path(user_id); 658 auto const paths = get_ce_key_paths(directory_path); 659 if (paths.empty()) { 660 LOG(ERROR) << "No ce keys present, cannot fixate for user " << user_id; 661 return false; 662 } 663 fixate_user_ce_key(directory_path, paths[0], paths); 664 return true; 665 } 666 667 // TODO: rename to 'install' for consistency, and take flags to know which keys to install 668 bool e4crypt_unlock_user_key(userid_t user_id, int serial, const char* token_hex, 669 const char* secret_hex) { 670 LOG(DEBUG) << "e4crypt_unlock_user_key " << user_id << " serial=" << serial 671 << " token_present=" << (strcmp(token_hex, "!") != 0); 672 if (e4crypt_is_native()) { 673 if (s_ce_key_raw_refs.count(user_id) != 0) { 674 LOG(WARNING) << "Tried to unlock already-unlocked key for user " << user_id; 675 return true; 676 } 677 std::string token, secret; 678 if (!parse_hex(token_hex, &token)) return false; 679 if (!parse_hex(secret_hex, &secret)) return false; 680 android::vold::KeyAuthentication auth(token, secret); 681 if (!read_and_install_user_ce_key(user_id, auth)) { 682 LOG(ERROR) << "Couldn't read key for " << user_id; 683 return false; 684 } 685 } else { 686 // When in emulation mode, we just use chmod. However, we also 687 // unlock directories when not in emulation mode, to bring devices 688 // back into a known-good state. 689 if (!emulated_unlock(android::vold::BuildDataSystemCePath(user_id), 0771) || 690 !emulated_unlock(android::vold::BuildDataMiscCePath(user_id), 01771) || 691 !emulated_unlock(android::vold::BuildDataMediaCePath(nullptr, user_id), 0770) || 692 !emulated_unlock(android::vold::BuildDataUserCePath(nullptr, user_id), 0771)) { 693 LOG(ERROR) << "Failed to unlock user " << user_id; 694 return false; 695 } 696 } 697 return true; 698 } 699 700 // TODO: rename to 'evict' for consistency 701 bool e4crypt_lock_user_key(userid_t user_id) { 702 LOG(DEBUG) << "e4crypt_lock_user_key " << user_id; 703 if (e4crypt_is_native()) { 704 return evict_ce_key(user_id); 705 } else if (e4crypt_is_emulated()) { 706 // When in emulation mode, we just use chmod 707 if (!emulated_lock(android::vold::BuildDataSystemCePath(user_id)) || 708 !emulated_lock(android::vold::BuildDataMiscCePath(user_id)) || 709 !emulated_lock(android::vold::BuildDataMediaCePath(nullptr, user_id)) || 710 !emulated_lock(android::vold::BuildDataUserCePath(nullptr, user_id))) { 711 LOG(ERROR) << "Failed to lock user " << user_id; 712 return false; 713 } 714 } 715 716 return true; 717 } 718 719 bool e4crypt_prepare_user_storage(const char* volume_uuid, userid_t user_id, int serial, 720 int flags) { 721 LOG(DEBUG) << "e4crypt_prepare_user_storage for volume " << escape_null(volume_uuid) 722 << ", user " << user_id << ", serial " << serial << ", flags " << flags; 723 724 if (flags & FLAG_STORAGE_DE) { 725 // DE_sys key 726 auto system_legacy_path = android::vold::BuildDataSystemLegacyPath(user_id); 727 auto misc_legacy_path = android::vold::BuildDataMiscLegacyPath(user_id); 728 auto profiles_de_path = android::vold::BuildDataProfilesDePath(user_id); 729 730 // DE_n key 731 auto system_de_path = android::vold::BuildDataSystemDePath(user_id); 732 auto misc_de_path = android::vold::BuildDataMiscDePath(user_id); 733 auto user_de_path = android::vold::BuildDataUserDePath(volume_uuid, user_id); 734 735 if (!prepare_dir(system_legacy_path, 0700, AID_SYSTEM, AID_SYSTEM)) return false; 736 #if MANAGE_MISC_DIRS 737 if (!prepare_dir(misc_legacy_path, 0750, multiuser_get_uid(user_id, AID_SYSTEM), 738 multiuser_get_uid(user_id, AID_EVERYBODY))) return false; 739 #endif 740 if (!prepare_dir(profiles_de_path, 0771, AID_SYSTEM, AID_SYSTEM)) return false; 741 742 if (!prepare_dir(system_de_path, 0770, AID_SYSTEM, AID_SYSTEM)) return false; 743 if (!prepare_dir(misc_de_path, 01771, AID_SYSTEM, AID_MISC)) return false; 744 if (!prepare_dir(user_de_path, 0771, AID_SYSTEM, AID_SYSTEM)) return false; 745 746 // For now, FBE is only supported on internal storage 747 if (e4crypt_is_native() && volume_uuid == nullptr) { 748 std::string de_raw_ref; 749 if (!lookup_key_ref(s_de_key_raw_refs, user_id, &de_raw_ref)) return false; 750 if (!ensure_policy(de_raw_ref, system_de_path)) return false; 751 if (!ensure_policy(de_raw_ref, misc_de_path)) return false; 752 if (!ensure_policy(de_raw_ref, user_de_path)) return false; 753 } 754 } 755 756 if (flags & FLAG_STORAGE_CE) { 757 // CE_n key 758 auto system_ce_path = android::vold::BuildDataSystemCePath(user_id); 759 auto misc_ce_path = android::vold::BuildDataMiscCePath(user_id); 760 auto media_ce_path = android::vold::BuildDataMediaCePath(volume_uuid, user_id); 761 auto user_ce_path = android::vold::BuildDataUserCePath(volume_uuid, user_id); 762 763 if (!prepare_dir(system_ce_path, 0770, AID_SYSTEM, AID_SYSTEM)) return false; 764 if (!prepare_dir(misc_ce_path, 01771, AID_SYSTEM, AID_MISC)) return false; 765 if (!prepare_dir(media_ce_path, 0770, AID_MEDIA_RW, AID_MEDIA_RW)) return false; 766 if (!prepare_dir(user_ce_path, 0771, AID_SYSTEM, AID_SYSTEM)) return false; 767 768 // For now, FBE is only supported on internal storage 769 if (e4crypt_is_native() && volume_uuid == nullptr) { 770 std::string ce_raw_ref; 771 if (!lookup_key_ref(s_ce_key_raw_refs, user_id, &ce_raw_ref)) return false; 772 if (!ensure_policy(ce_raw_ref, system_ce_path)) return false; 773 if (!ensure_policy(ce_raw_ref, misc_ce_path)) return false; 774 if (!ensure_policy(ce_raw_ref, media_ce_path)) return false; 775 if (!ensure_policy(ce_raw_ref, user_ce_path)) return false; 776 777 // Now that credentials have been installed, we can run restorecon 778 // over these paths 779 // NOTE: these paths need to be kept in sync with libselinux 780 android::vold::RestoreconRecursive(system_ce_path); 781 android::vold::RestoreconRecursive(misc_ce_path); 782 } 783 } 784 785 return true; 786 } 787 788 bool e4crypt_destroy_user_storage(const char* volume_uuid, userid_t user_id, int flags) { 789 LOG(DEBUG) << "e4crypt_destroy_user_storage for volume " << escape_null(volume_uuid) 790 << ", user " << user_id << ", flags " << flags; 791 bool res = true; 792 793 if (flags & FLAG_STORAGE_DE) { 794 // DE_sys key 795 auto system_legacy_path = android::vold::BuildDataSystemLegacyPath(user_id); 796 auto misc_legacy_path = android::vold::BuildDataMiscLegacyPath(user_id); 797 auto profiles_de_path = android::vold::BuildDataProfilesDePath(user_id); 798 799 // DE_n key 800 auto system_de_path = android::vold::BuildDataSystemDePath(user_id); 801 auto misc_de_path = android::vold::BuildDataMiscDePath(user_id); 802 auto user_de_path = android::vold::BuildDataUserDePath(volume_uuid, user_id); 803 804 if (volume_uuid == nullptr) { 805 res &= destroy_dir(system_legacy_path); 806 #if MANAGE_MISC_DIRS 807 res &= destroy_dir(misc_legacy_path); 808 #endif 809 res &= destroy_dir(profiles_de_path); 810 res &= destroy_dir(system_de_path); 811 res &= destroy_dir(misc_de_path); 812 } 813 res &= destroy_dir(user_de_path); 814 } 815 816 if (flags & FLAG_STORAGE_CE) { 817 // CE_n key 818 auto system_ce_path = android::vold::BuildDataSystemCePath(user_id); 819 auto misc_ce_path = android::vold::BuildDataMiscCePath(user_id); 820 auto media_ce_path = android::vold::BuildDataMediaCePath(volume_uuid, user_id); 821 auto user_ce_path = android::vold::BuildDataUserCePath(volume_uuid, user_id); 822 823 if (volume_uuid == nullptr) { 824 res &= destroy_dir(system_ce_path); 825 res &= destroy_dir(misc_ce_path); 826 } 827 res &= destroy_dir(media_ce_path); 828 res &= destroy_dir(user_ce_path); 829 } 830 831 return res; 832 } 833 834 bool e4crypt_secdiscard(const char* path) { 835 return android::vold::runSecdiscardSingle(std::string(path)); 836 } 837
