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 #include "ext4_crypt.h" 44 #include "key_control.h" 45 46 #define EMULATED_USES_SELINUX 0 47 #define MANAGE_MISC_DIRS 0 48 49 #include <cutils/fs.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 const std::string device_key_dir = std::string() + DATA_MNT_POINT + e4crypt_unencrypted_folder; 64 const std::string device_key_path = device_key_dir + "/key"; 65 const std::string device_key_temp = device_key_dir + "/temp"; 66 67 const std::string user_key_dir = std::string() + DATA_MNT_POINT + "/misc/vold/user_keys"; 68 const std::string user_key_temp = user_key_dir + "/temp"; 69 70 bool s_global_de_initialized = false; 71 72 // Some users are ephemeral, don't try to wipe their keys from disk 73 std::set<userid_t> s_ephemeral_users; 74 75 // Map user ids to key references 76 std::map<userid_t, std::string> s_de_key_raw_refs; 77 std::map<userid_t, std::string> s_ce_key_raw_refs; 78 // TODO abolish this map. Keys should not be long-lived in user memory, only kernel memory. 79 // See 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 (auto 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 if (e4crypt_policy_ensure(path.c_str(), 378 raw_ref.data(), raw_ref.size(), 379 cryptfs_get_file_encryption_mode()) != 0) { 380 LOG(ERROR) << "Failed to set policy on: " << path; 381 return false; 382 } 383 return true; 384 } 385 386 static bool is_numeric(const char* name) { 387 for (const char* p = name; *p != '\0'; p++) { 388 if (!isdigit(*p)) return false; 389 } 390 return true; 391 } 392 393 static bool load_all_de_keys() { 394 auto de_dir = user_key_dir + "/de"; 395 auto dirp = std::unique_ptr<DIR, int (*)(DIR*)>(opendir(de_dir.c_str()), closedir); 396 if (!dirp) { 397 PLOG(ERROR) << "Unable to read de key directory"; 398 return false; 399 } 400 for (;;) { 401 errno = 0; 402 auto entry = readdir(dirp.get()); 403 if (!entry) { 404 if (errno) { 405 PLOG(ERROR) << "Unable to read de key directory"; 406 return false; 407 } 408 break; 409 } 410 if (entry->d_type != DT_DIR || !is_numeric(entry->d_name)) { 411 LOG(DEBUG) << "Skipping non-de-key " << entry->d_name; 412 continue; 413 } 414 userid_t user_id = atoi(entry->d_name); 415 if (s_de_key_raw_refs.count(user_id) == 0) { 416 auto key_path = de_dir + "/" + entry->d_name; 417 std::string key; 418 if (!android::vold::retrieveKey(key_path, kEmptyAuthentication, &key)) return false; 419 std::string raw_ref; 420 if (!install_key(key, &raw_ref)) return false; 421 s_de_key_raw_refs[user_id] = raw_ref; 422 LOG(DEBUG) << "Installed de key for user " << user_id; 423 } 424 } 425 // ext4enc:TODO: go through all DE directories, ensure that all user dirs have the 426 // correct policy set on them, and that no rogue ones exist. 427 return true; 428 } 429 430 bool e4crypt_initialize_global_de() { 431 LOG(INFO) << "e4crypt_initialize_global_de"; 432 433 if (s_global_de_initialized) { 434 LOG(INFO) << "Already initialized"; 435 return true; 436 } 437 438 std::string mode_filename = std::string("/data") + e4crypt_key_mode; 439 std::string mode = cryptfs_get_file_encryption_mode(); 440 if (!android::base::WriteStringToFile(mode, mode_filename)) { 441 PLOG(ERROR) << "Cannot save type"; 442 return false; 443 } 444 445 std::string device_key; 446 if (path_exists(device_key_path)) { 447 if (!android::vold::retrieveKey(device_key_path, 448 kEmptyAuthentication, &device_key)) return false; 449 } else { 450 LOG(INFO) << "Creating new key"; 451 if (!random_key(&device_key)) return false; 452 if (!store_key(device_key_path, device_key_temp, 453 kEmptyAuthentication, device_key)) return false; 454 } 455 456 std::string device_key_ref; 457 if (!install_key(device_key, &device_key_ref)) { 458 LOG(ERROR) << "Failed to install device key"; 459 return false; 460 } 461 462 std::string ref_filename = std::string("/data") + e4crypt_key_ref; 463 if (!android::base::WriteStringToFile(device_key_ref, ref_filename)) { 464 PLOG(ERROR) << "Cannot save key reference"; 465 return false; 466 } 467 468 s_global_de_initialized = true; 469 return true; 470 } 471 472 bool e4crypt_init_user0() { 473 LOG(DEBUG) << "e4crypt_init_user0"; 474 if (e4crypt_is_native()) { 475 if (!prepare_dir(user_key_dir, 0700, AID_ROOT, AID_ROOT)) return false; 476 if (!prepare_dir(user_key_dir + "/ce", 0700, AID_ROOT, AID_ROOT)) return false; 477 if (!prepare_dir(user_key_dir + "/de", 0700, AID_ROOT, AID_ROOT)) return false; 478 if (!path_exists(get_de_key_path(0))) { 479 if (!create_and_install_user_keys(0, false)) return false; 480 } 481 // TODO: switch to loading only DE_0 here once framework makes 482 // explicit calls to install DE keys for secondary users 483 if (!load_all_de_keys()) return false; 484 } 485 // We can only safely prepare DE storage here, since CE keys are probably 486 // entangled with user credentials. The framework will always prepare CE 487 // storage once CE keys are installed. 488 if (!e4crypt_prepare_user_storage(nullptr, 0, 0, FLAG_STORAGE_DE)) { 489 LOG(ERROR) << "Failed to prepare user 0 storage"; 490 return false; 491 } 492 493 // If this is a non-FBE device that recently left an emulated mode, 494 // restore user data directories to known-good state. 495 if (!e4crypt_is_native() && !e4crypt_is_emulated()) { 496 e4crypt_unlock_user_key(0, 0, "!", "!"); 497 } 498 499 return true; 500 } 501 502 bool e4crypt_vold_create_user_key(userid_t user_id, int serial, bool ephemeral) { 503 LOG(DEBUG) << "e4crypt_vold_create_user_key for " << user_id << " serial " << serial; 504 if (!e4crypt_is_native()) { 505 return true; 506 } 507 // FIXME test for existence of key that is not loaded yet 508 if (s_ce_key_raw_refs.count(user_id) != 0) { 509 LOG(ERROR) << "Already exists, can't e4crypt_vold_create_user_key for " << user_id 510 << " serial " << serial; 511 // FIXME should we fail the command? 512 return true; 513 } 514 if (!create_and_install_user_keys(user_id, ephemeral)) { 515 return false; 516 } 517 return true; 518 } 519 520 bool e4crypt_destroy_user_key(userid_t user_id) { 521 LOG(DEBUG) << "e4crypt_destroy_user_key(" << user_id << ")"; 522 if (!e4crypt_is_native()) { 523 return true; 524 } 525 bool success = true; 526 s_ce_keys.erase(user_id); 527 std::string raw_ref; 528 s_ce_key_raw_refs.erase(user_id); 529 s_de_key_raw_refs.erase(user_id); 530 auto it = s_ephemeral_users.find(user_id); 531 if (it != s_ephemeral_users.end()) { 532 s_ephemeral_users.erase(it); 533 } else { 534 for (auto const path: get_ce_key_paths(get_ce_key_directory_path(user_id))) { 535 success &= android::vold::destroyKey(path); 536 } 537 auto de_key_path = get_de_key_path(user_id); 538 if (path_exists(de_key_path)) { 539 success &= android::vold::destroyKey(de_key_path); 540 } else { 541 LOG(INFO) << "Not present so not erasing: " << de_key_path; 542 } 543 } 544 return success; 545 } 546 547 static bool emulated_lock(const std::string& path) { 548 if (chmod(path.c_str(), 0000) != 0) { 549 PLOG(ERROR) << "Failed to chmod " << path; 550 return false; 551 } 552 #if EMULATED_USES_SELINUX 553 if (setfilecon(path.c_str(), "u:object_r:storage_stub_file:s0") != 0) { 554 PLOG(WARNING) << "Failed to setfilecon " << path; 555 return false; 556 } 557 #endif 558 return true; 559 } 560 561 static bool emulated_unlock(const std::string& path, mode_t mode) { 562 if (chmod(path.c_str(), mode) != 0) { 563 PLOG(ERROR) << "Failed to chmod " << path; 564 // FIXME temporary workaround for b/26713622 565 if (e4crypt_is_emulated()) return false; 566 } 567 #if EMULATED_USES_SELINUX 568 if (selinux_android_restorecon(path.c_str(), SELINUX_ANDROID_RESTORECON_FORCE) != 0) { 569 PLOG(WARNING) << "Failed to restorecon " << path; 570 // FIXME temporary workaround for b/26713622 571 if (e4crypt_is_emulated()) return false; 572 } 573 #endif 574 return true; 575 } 576 577 static bool parse_hex(const char* hex, std::string* result) { 578 if (strcmp("!", hex) == 0) { 579 *result = ""; 580 return true; 581 } 582 if (android::vold::HexToStr(hex, *result) != 0) { 583 LOG(ERROR) << "Invalid FBE hex string"; // Don't log the string for security reasons 584 return false; 585 } 586 return true; 587 } 588 589 bool e4crypt_add_user_key_auth(userid_t user_id, int serial, const char* token_hex, 590 const char* secret_hex) { 591 LOG(DEBUG) << "e4crypt_add_user_key_auth " << user_id << " serial=" << serial 592 << " token_present=" << (strcmp(token_hex, "!") != 0); 593 if (!e4crypt_is_native()) return true; 594 if (s_ephemeral_users.count(user_id) != 0) return true; 595 std::string token, secret; 596 if (!parse_hex(token_hex, &token)) return false; 597 if (!parse_hex(secret_hex, &secret)) return false; 598 auto auth = secret.empty() ? kEmptyAuthentication 599 : android::vold::KeyAuthentication(token, secret); 600 auto it = s_ce_keys.find(user_id); 601 if (it == s_ce_keys.end()) { 602 LOG(ERROR) << "Key not loaded into memory, can't change for user " << user_id; 603 return false; 604 } 605 auto ce_key = it->second; 606 auto const directory_path = get_ce_key_directory_path(user_id); 607 auto const paths = get_ce_key_paths(directory_path); 608 std::string ce_key_path; 609 if (!get_ce_key_new_path(directory_path, paths, &ce_key_path)) return false; 610 if (!store_key(ce_key_path, user_key_temp, auth, ce_key)) return false; 611 return true; 612 } 613 614 bool e4crypt_fixate_newest_user_key_auth(userid_t user_id) { 615 LOG(DEBUG) << "e4crypt_fixate_newest_user_key_auth " << user_id; 616 if (!e4crypt_is_native()) return true; 617 if (s_ephemeral_users.count(user_id) != 0) return true; 618 auto const directory_path = get_ce_key_directory_path(user_id); 619 auto const paths = get_ce_key_paths(directory_path); 620 if (paths.empty()) { 621 LOG(ERROR) << "No ce keys present, cannot fixate for user " << user_id; 622 return false; 623 } 624 fixate_user_ce_key(directory_path, paths[0], paths); 625 return true; 626 } 627 628 // TODO: rename to 'install' for consistency, and take flags to know which keys to install 629 bool e4crypt_unlock_user_key(userid_t user_id, int serial, const char* token_hex, 630 const char* secret_hex) { 631 LOG(DEBUG) << "e4crypt_unlock_user_key " << user_id << " serial=" << serial 632 << " token_present=" << (strcmp(token_hex, "!") != 0); 633 if (e4crypt_is_native()) { 634 if (s_ce_key_raw_refs.count(user_id) != 0) { 635 LOG(WARNING) << "Tried to unlock already-unlocked key for user " << user_id; 636 return true; 637 } 638 std::string token, secret; 639 if (!parse_hex(token_hex, &token)) return false; 640 if (!parse_hex(secret_hex, &secret)) return false; 641 android::vold::KeyAuthentication auth(token, secret); 642 if (!read_and_install_user_ce_key(user_id, auth)) { 643 LOG(ERROR) << "Couldn't read key for " << user_id; 644 return false; 645 } 646 } else { 647 // When in emulation mode, we just use chmod. However, we also 648 // unlock directories when not in emulation mode, to bring devices 649 // back into a known-good state. 650 if (!emulated_unlock(android::vold::BuildDataSystemCePath(user_id), 0771) || 651 !emulated_unlock(android::vold::BuildDataMiscCePath(user_id), 01771) || 652 !emulated_unlock(android::vold::BuildDataMediaCePath(nullptr, user_id), 0770) || 653 !emulated_unlock(android::vold::BuildDataUserCePath(nullptr, user_id), 0771)) { 654 LOG(ERROR) << "Failed to unlock user " << user_id; 655 return false; 656 } 657 } 658 return true; 659 } 660 661 // TODO: rename to 'evict' for consistency 662 bool e4crypt_lock_user_key(userid_t user_id) { 663 if (e4crypt_is_native()) { 664 // TODO: remove from kernel keyring 665 } else if (e4crypt_is_emulated()) { 666 // When in emulation mode, we just use chmod 667 if (!emulated_lock(android::vold::BuildDataSystemCePath(user_id)) || 668 !emulated_lock(android::vold::BuildDataMiscCePath(user_id)) || 669 !emulated_lock(android::vold::BuildDataMediaCePath(nullptr, user_id)) || 670 !emulated_lock(android::vold::BuildDataUserCePath(nullptr, user_id))) { 671 LOG(ERROR) << "Failed to lock user " << user_id; 672 return false; 673 } 674 } 675 676 return true; 677 } 678 679 bool e4crypt_prepare_user_storage(const char* volume_uuid, userid_t user_id, int serial, 680 int flags) { 681 LOG(DEBUG) << "e4crypt_prepare_user_storage for volume " << escape_null(volume_uuid) 682 << ", user " << user_id << ", serial " << serial << ", flags " << flags; 683 684 if (flags & FLAG_STORAGE_DE) { 685 // DE_sys key 686 auto system_legacy_path = android::vold::BuildDataSystemLegacyPath(user_id); 687 auto misc_legacy_path = android::vold::BuildDataMiscLegacyPath(user_id); 688 auto profiles_de_path = android::vold::BuildDataProfilesDePath(user_id); 689 auto foreign_de_path = android::vold::BuildDataProfilesForeignDexDePath(user_id); 690 691 // DE_n key 692 auto system_de_path = android::vold::BuildDataSystemDePath(user_id); 693 auto misc_de_path = android::vold::BuildDataMiscDePath(user_id); 694 auto user_de_path = android::vold::BuildDataUserDePath(volume_uuid, user_id); 695 696 if (!prepare_dir(system_legacy_path, 0700, AID_SYSTEM, AID_SYSTEM)) return false; 697 #if MANAGE_MISC_DIRS 698 if (!prepare_dir(misc_legacy_path, 0750, multiuser_get_uid(user_id, AID_SYSTEM), 699 multiuser_get_uid(user_id, AID_EVERYBODY))) return false; 700 #endif 701 if (!prepare_dir(profiles_de_path, 0771, AID_SYSTEM, AID_SYSTEM)) return false; 702 if (!prepare_dir(foreign_de_path, 0773, AID_SYSTEM, AID_SYSTEM)) return false; 703 704 if (!prepare_dir(system_de_path, 0770, AID_SYSTEM, AID_SYSTEM)) return false; 705 if (!prepare_dir(misc_de_path, 01771, AID_SYSTEM, AID_MISC)) return false; 706 if (!prepare_dir(user_de_path, 0771, AID_SYSTEM, AID_SYSTEM)) return false; 707 708 // For now, FBE is only supported on internal storage 709 if (e4crypt_is_native() && volume_uuid == nullptr) { 710 std::string de_raw_ref; 711 if (!lookup_key_ref(s_de_key_raw_refs, user_id, &de_raw_ref)) return false; 712 if (!ensure_policy(de_raw_ref, system_de_path)) return false; 713 if (!ensure_policy(de_raw_ref, misc_de_path)) return false; 714 if (!ensure_policy(de_raw_ref, user_de_path)) return false; 715 } 716 } 717 718 if (flags & FLAG_STORAGE_CE) { 719 // CE_n key 720 auto system_ce_path = android::vold::BuildDataSystemCePath(user_id); 721 auto misc_ce_path = android::vold::BuildDataMiscCePath(user_id); 722 auto media_ce_path = android::vold::BuildDataMediaCePath(volume_uuid, user_id); 723 auto user_ce_path = android::vold::BuildDataUserCePath(volume_uuid, user_id); 724 725 if (!prepare_dir(system_ce_path, 0770, AID_SYSTEM, AID_SYSTEM)) return false; 726 if (!prepare_dir(misc_ce_path, 01771, AID_SYSTEM, AID_MISC)) return false; 727 if (!prepare_dir(media_ce_path, 0770, AID_MEDIA_RW, AID_MEDIA_RW)) return false; 728 if (!prepare_dir(user_ce_path, 0771, AID_SYSTEM, AID_SYSTEM)) return false; 729 730 // For now, FBE is only supported on internal storage 731 if (e4crypt_is_native() && volume_uuid == nullptr) { 732 std::string ce_raw_ref; 733 if (!lookup_key_ref(s_ce_key_raw_refs, user_id, &ce_raw_ref)) return false; 734 if (!ensure_policy(ce_raw_ref, system_ce_path)) return false; 735 if (!ensure_policy(ce_raw_ref, misc_ce_path)) return false; 736 if (!ensure_policy(ce_raw_ref, media_ce_path)) return false; 737 if (!ensure_policy(ce_raw_ref, user_ce_path)) return false; 738 739 // Now that credentials have been installed, we can run restorecon 740 // over these paths 741 // NOTE: these paths need to be kept in sync with libselinux 742 android::vold::RestoreconRecursive(system_ce_path); 743 android::vold::RestoreconRecursive(misc_ce_path); 744 } 745 } 746 747 return true; 748 } 749 750 bool e4crypt_destroy_user_storage(const char* volume_uuid, userid_t user_id, int flags) { 751 LOG(DEBUG) << "e4crypt_destroy_user_storage for volume " << escape_null(volume_uuid) 752 << ", user " << user_id << ", flags " << flags; 753 bool res = true; 754 755 if (flags & FLAG_STORAGE_DE) { 756 // DE_sys key 757 auto system_legacy_path = android::vold::BuildDataSystemLegacyPath(user_id); 758 auto misc_legacy_path = android::vold::BuildDataMiscLegacyPath(user_id); 759 auto profiles_de_path = android::vold::BuildDataProfilesDePath(user_id); 760 auto foreign_de_path = android::vold::BuildDataProfilesForeignDexDePath(user_id); 761 762 // DE_n key 763 auto system_de_path = android::vold::BuildDataSystemDePath(user_id); 764 auto misc_de_path = android::vold::BuildDataMiscDePath(user_id); 765 auto user_de_path = android::vold::BuildDataUserDePath(volume_uuid, user_id); 766 767 if (volume_uuid == nullptr) { 768 res &= destroy_dir(system_legacy_path); 769 #if MANAGE_MISC_DIRS 770 res &= destroy_dir(misc_legacy_path); 771 #endif 772 res &= destroy_dir(profiles_de_path); 773 res &= destroy_dir(foreign_de_path); 774 res &= destroy_dir(system_de_path); 775 res &= destroy_dir(misc_de_path); 776 } 777 res &= destroy_dir(user_de_path); 778 } 779 780 if (flags & FLAG_STORAGE_CE) { 781 // CE_n key 782 auto system_ce_path = android::vold::BuildDataSystemCePath(user_id); 783 auto misc_ce_path = android::vold::BuildDataMiscCePath(user_id); 784 auto media_ce_path = android::vold::BuildDataMediaCePath(volume_uuid, user_id); 785 auto user_ce_path = android::vold::BuildDataUserCePath(volume_uuid, user_id); 786 787 if (volume_uuid == nullptr) { 788 res &= destroy_dir(system_ce_path); 789 res &= destroy_dir(misc_ce_path); 790 } 791 res &= destroy_dir(media_ce_path); 792 res &= destroy_dir(user_ce_path); 793 } 794 795 return res; 796 } 797
