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 return true; 174 } 175 176 static std::string get_de_key_path(userid_t user_id) { 177 return StringPrintf("%s/de/%d", user_key_dir.c_str(), user_id); 178 } 179 180 static std::string get_ce_key_directory_path(userid_t user_id) { 181 return StringPrintf("%s/ce/%d", user_key_dir.c_str(), user_id); 182 } 183 184 // Returns the keys newest first 185 static std::vector<std::string> get_ce_key_paths(const std::string& directory_path) { 186 auto dirp = std::unique_ptr<DIR, int (*)(DIR*)>(opendir(directory_path.c_str()), closedir); 187 if (!dirp) { 188 PLOG(ERROR) << "Unable to open ce key directory: " + directory_path; 189 return std::vector<std::string>(); 190 } 191 std::vector<std::string> result; 192 for (;;) { 193 errno = 0; 194 auto const entry = readdir(dirp.get()); 195 if (!entry) { 196 if (errno) { 197 PLOG(ERROR) << "Unable to read ce key directory: " + directory_path; 198 return std::vector<std::string>(); 199 } 200 break; 201 } 202 if (entry->d_type != DT_DIR || entry->d_name[0] != 'c') { 203 LOG(DEBUG) << "Skipping non-key " << entry->d_name; 204 continue; 205 } 206 result.emplace_back(directory_path + "/" + entry->d_name); 207 } 208 std::sort(result.begin(), result.end()); 209 std::reverse(result.begin(), result.end()); 210 return result; 211 } 212 213 static std::string get_ce_key_current_path(const std::string& directory_path) { 214 return directory_path + "/current"; 215 } 216 217 static bool get_ce_key_new_path(const std::string& directory_path, 218 const std::vector<std::string>& paths, 219 std::string *ce_key_path) { 220 if (paths.empty()) { 221 *ce_key_path = get_ce_key_current_path(directory_path); 222 return true; 223 } 224 for (unsigned int i = 0; i < UINT_MAX; i++) { 225 auto const candidate = StringPrintf("%s/cx%010u", directory_path.c_str(), i); 226 if (paths[0] < candidate) { 227 *ce_key_path = candidate; 228 return true; 229 } 230 } 231 return false; 232 } 233 234 // Discard all keys but the named one; rename it to canonical name. 235 // No point in acting on errors in this; ignore them. 236 static void fixate_user_ce_key(const std::string& directory_path, const std::string &to_fix, 237 const std::vector<std::string>& paths) { 238 for (auto const other_path: paths) { 239 if (other_path != to_fix) { 240 android::vold::destroyKey(other_path); 241 } 242 } 243 auto const current_path = get_ce_key_current_path(directory_path); 244 if (to_fix != current_path) { 245 LOG(DEBUG) << "Renaming " << to_fix << " to " << current_path; 246 if (rename(to_fix.c_str(), current_path.c_str()) != 0) { 247 PLOG(WARNING) << "Unable to rename " << to_fix << " to " << current_path; 248 } 249 } 250 } 251 252 static bool read_and_fixate_user_ce_key(userid_t user_id, 253 const android::vold::KeyAuthentication& auth, 254 std::string *ce_key) { 255 auto const directory_path = get_ce_key_directory_path(user_id); 256 auto const paths = get_ce_key_paths(directory_path); 257 for (auto const ce_key_path: paths) { 258 LOG(DEBUG) << "Trying user CE key " << ce_key_path; 259 if (android::vold::retrieveKey(ce_key_path, auth, ce_key)) { 260 LOG(DEBUG) << "Successfully retrieved key"; 261 fixate_user_ce_key(directory_path, ce_key_path, paths); 262 return true; 263 } 264 } 265 LOG(ERROR) << "Failed to find working ce key for user " << user_id; 266 return false; 267 } 268 269 static bool read_and_install_user_ce_key(userid_t user_id, 270 const android::vold::KeyAuthentication& auth) { 271 if (s_ce_key_raw_refs.count(user_id) != 0) return true; 272 std::string ce_key; 273 if (!read_and_fixate_user_ce_key(user_id, auth, &ce_key)) return false; 274 std::string ce_raw_ref; 275 if (!install_key(ce_key, &ce_raw_ref)) return false; 276 s_ce_keys[user_id] = ce_key; 277 s_ce_key_raw_refs[user_id] = ce_raw_ref; 278 LOG(DEBUG) << "Installed ce key for user " << user_id; 279 return true; 280 } 281 282 static bool prepare_dir(const std::string& dir, mode_t mode, uid_t uid, gid_t gid) { 283 LOG(DEBUG) << "Preparing: " << dir; 284 if (fs_prepare_dir(dir.c_str(), mode, uid, gid) != 0) { 285 PLOG(ERROR) << "Failed to prepare " << dir; 286 return false; 287 } 288 return true; 289 } 290 291 static bool destroy_dir(const std::string& dir) { 292 LOG(DEBUG) << "Destroying: " << dir; 293 if (rmdir(dir.c_str()) != 0 && errno != ENOENT) { 294 PLOG(ERROR) << "Failed to destroy " << dir; 295 return false; 296 } 297 return true; 298 } 299 300 static bool random_key(std::string* key) { 301 if (android::vold::ReadRandomBytes(EXT4_AES_256_XTS_KEY_SIZE, *key) != 0) { 302 // TODO status_t plays badly with PLOG, fix it. 303 LOG(ERROR) << "Random read failed"; 304 return false; 305 } 306 return true; 307 } 308 309 static bool path_exists(const std::string& path) { 310 return access(path.c_str(), F_OK) == 0; 311 } 312 313 // NB this assumes that there is only one thread listening for crypt commands, because 314 // it creates keys in a fixed location. 315 static bool store_key(const std::string& key_path, const std::string& tmp_path, 316 const android::vold::KeyAuthentication& auth, const std::string& key) { 317 if (path_exists(key_path)) { 318 LOG(ERROR) << "Already exists, cannot create key at: " << key_path; 319 return false; 320 } 321 if (path_exists(tmp_path)) { 322 android::vold::destroyKey(tmp_path); // May be partially created so ignore errors 323 } 324 if (!android::vold::storeKey(tmp_path, auth, key)) return false; 325 if (rename(tmp_path.c_str(), key_path.c_str()) != 0) { 326 PLOG(ERROR) << "Unable to move new key to location: " << key_path; 327 return false; 328 } 329 LOG(DEBUG) << "Created key " << key_path; 330 return true; 331 } 332 333 static bool create_and_install_user_keys(userid_t user_id, bool create_ephemeral) { 334 std::string de_key, ce_key; 335 if (!random_key(&de_key)) return false; 336 if (!random_key(&ce_key)) return false; 337 if (create_ephemeral) { 338 // If the key should be created as ephemeral, don't store it. 339 s_ephemeral_users.insert(user_id); 340 } else { 341 auto const directory_path = get_ce_key_directory_path(user_id); 342 if (!prepare_dir(directory_path, 0700, AID_ROOT, AID_ROOT)) return false; 343 auto const paths = get_ce_key_paths(directory_path); 344 std::string ce_key_path; 345 if (!get_ce_key_new_path(directory_path, paths, &ce_key_path)) return false; 346 if (!store_key(ce_key_path, user_key_temp, 347 kEmptyAuthentication, ce_key)) return false; 348 fixate_user_ce_key(directory_path, ce_key_path, paths); 349 // Write DE key second; once this is written, all is good. 350 if (!store_key(get_de_key_path(user_id), user_key_temp, 351 kEmptyAuthentication, de_key)) return false; 352 } 353 std::string de_raw_ref; 354 if (!install_key(de_key, &de_raw_ref)) return false; 355 s_de_key_raw_refs[user_id] = de_raw_ref; 356 std::string ce_raw_ref; 357 if (!install_key(ce_key, &ce_raw_ref)) return false; 358 s_ce_keys[user_id] = ce_key; 359 s_ce_key_raw_refs[user_id] = ce_raw_ref; 360 LOG(DEBUG) << "Created keys for user " << user_id; 361 return true; 362 } 363 364 static bool lookup_key_ref(const std::map<userid_t, std::string>& key_map, userid_t user_id, 365 std::string* raw_ref) { 366 auto refi = key_map.find(user_id); 367 if (refi == key_map.end()) { 368 LOG(ERROR) << "Cannot find key for " << user_id; 369 return false; 370 } 371 *raw_ref = refi->second; 372 return true; 373 } 374 375 static bool ensure_policy(const std::string& raw_ref, const std::string& path) { 376 if (e4crypt_policy_ensure(path.c_str(), raw_ref.data(), raw_ref.size()) != 0) { 377 LOG(ERROR) << "Failed to set policy on: " << path; 378 return false; 379 } 380 return true; 381 } 382 383 static bool is_numeric(const char* name) { 384 for (const char* p = name; *p != '\0'; p++) { 385 if (!isdigit(*p)) return false; 386 } 387 return true; 388 } 389 390 static bool load_all_de_keys() { 391 auto de_dir = user_key_dir + "/de"; 392 auto dirp = std::unique_ptr<DIR, int (*)(DIR*)>(opendir(de_dir.c_str()), closedir); 393 if (!dirp) { 394 PLOG(ERROR) << "Unable to read de key directory"; 395 return false; 396 } 397 for (;;) { 398 errno = 0; 399 auto entry = readdir(dirp.get()); 400 if (!entry) { 401 if (errno) { 402 PLOG(ERROR) << "Unable to read de key directory"; 403 return false; 404 } 405 break; 406 } 407 if (entry->d_type != DT_DIR || !is_numeric(entry->d_name)) { 408 LOG(DEBUG) << "Skipping non-de-key " << entry->d_name; 409 continue; 410 } 411 userid_t user_id = atoi(entry->d_name); 412 if (s_de_key_raw_refs.count(user_id) == 0) { 413 auto key_path = de_dir + "/" + entry->d_name; 414 std::string key; 415 if (!android::vold::retrieveKey(key_path, kEmptyAuthentication, &key)) return false; 416 std::string raw_ref; 417 if (!install_key(key, &raw_ref)) return false; 418 s_de_key_raw_refs[user_id] = raw_ref; 419 LOG(DEBUG) << "Installed de key for user " << user_id; 420 } 421 } 422 // ext4enc:TODO: go through all DE directories, ensure that all user dirs have the 423 // correct policy set on them, and that no rogue ones exist. 424 return true; 425 } 426 427 bool e4crypt_initialize_global_de() { 428 LOG(INFO) << "e4crypt_initialize_global_de"; 429 430 if (s_global_de_initialized) { 431 LOG(INFO) << "Already initialized"; 432 return true; 433 } 434 435 std::string device_key; 436 if (path_exists(device_key_path)) { 437 if (!android::vold::retrieveKey(device_key_path, 438 kEmptyAuthentication, &device_key)) return false; 439 } else { 440 LOG(INFO) << "Creating new key"; 441 if (!random_key(&device_key)) return false; 442 if (!store_key(device_key_path, device_key_temp, 443 kEmptyAuthentication, device_key)) return false; 444 } 445 446 std::string device_key_ref; 447 if (!install_key(device_key, &device_key_ref)) { 448 LOG(ERROR) << "Failed to install device key"; 449 return false; 450 } 451 452 std::string ref_filename = std::string("/data") + e4crypt_key_ref; 453 if (!android::base::WriteStringToFile(device_key_ref, ref_filename)) { 454 PLOG(ERROR) << "Cannot save key reference"; 455 return false; 456 } 457 458 s_global_de_initialized = true; 459 return true; 460 } 461 462 bool e4crypt_init_user0() { 463 LOG(DEBUG) << "e4crypt_init_user0"; 464 if (e4crypt_is_native()) { 465 if (!prepare_dir(user_key_dir, 0700, AID_ROOT, AID_ROOT)) return false; 466 if (!prepare_dir(user_key_dir + "/ce", 0700, AID_ROOT, AID_ROOT)) return false; 467 if (!prepare_dir(user_key_dir + "/de", 0700, AID_ROOT, AID_ROOT)) return false; 468 if (!path_exists(get_de_key_path(0))) { 469 if (!create_and_install_user_keys(0, false)) return false; 470 } 471 // TODO: switch to loading only DE_0 here once framework makes 472 // explicit calls to install DE keys for secondary users 473 if (!load_all_de_keys()) return false; 474 } 475 // We can only safely prepare DE storage here, since CE keys are probably 476 // entangled with user credentials. The framework will always prepare CE 477 // storage once CE keys are installed. 478 if (!e4crypt_prepare_user_storage(nullptr, 0, 0, FLAG_STORAGE_DE)) { 479 LOG(ERROR) << "Failed to prepare user 0 storage"; 480 return false; 481 } 482 483 // If this is a non-FBE device that recently left an emulated mode, 484 // restore user data directories to known-good state. 485 if (!e4crypt_is_native() && !e4crypt_is_emulated()) { 486 e4crypt_unlock_user_key(0, 0, "!", "!"); 487 } 488 489 return true; 490 } 491 492 bool e4crypt_vold_create_user_key(userid_t user_id, int serial, bool ephemeral) { 493 LOG(DEBUG) << "e4crypt_vold_create_user_key for " << user_id << " serial " << serial; 494 if (!e4crypt_is_native()) { 495 return true; 496 } 497 // FIXME test for existence of key that is not loaded yet 498 if (s_ce_key_raw_refs.count(user_id) != 0) { 499 LOG(ERROR) << "Already exists, can't e4crypt_vold_create_user_key for " << user_id 500 << " serial " << serial; 501 // FIXME should we fail the command? 502 return true; 503 } 504 if (!create_and_install_user_keys(user_id, ephemeral)) { 505 return false; 506 } 507 return true; 508 } 509 510 static bool evict_key(const std::string& raw_ref) { 511 auto ref = keyname(raw_ref); 512 key_serial_t device_keyring; 513 if (!e4crypt_keyring(&device_keyring)) return false; 514 auto key_serial = keyctl_search(device_keyring, "logon", ref.c_str(), 0); 515 if (keyctl_revoke(key_serial) != 0) { 516 PLOG(ERROR) << "Failed to revoke key with serial " << key_serial << " ref " << ref; 517 return false; 518 } 519 LOG(DEBUG) << "Revoked key with serial " << key_serial << " ref " << ref; 520 return true; 521 } 522 523 bool e4crypt_destroy_user_key(userid_t user_id) { 524 LOG(DEBUG) << "e4crypt_destroy_user_key(" << user_id << ")"; 525 if (!e4crypt_is_native()) { 526 return true; 527 } 528 bool success = true; 529 s_ce_keys.erase(user_id); 530 std::string raw_ref; 531 // If we haven't loaded the CE key, no need to evict it. 532 if (lookup_key_ref(s_ce_key_raw_refs, user_id, &raw_ref)) { 533 success &= evict_key(raw_ref); 534 } 535 s_ce_key_raw_refs.erase(user_id); 536 success &= lookup_key_ref(s_de_key_raw_refs, user_id, &raw_ref) && evict_key(raw_ref); 537 s_de_key_raw_refs.erase(user_id); 538 auto it = s_ephemeral_users.find(user_id); 539 if (it != s_ephemeral_users.end()) { 540 s_ephemeral_users.erase(it); 541 } else { 542 for (auto const path: get_ce_key_paths(get_ce_key_directory_path(user_id))) { 543 success &= android::vold::destroyKey(path); 544 } 545 success &= android::vold::destroyKey(get_de_key_path(user_id)); 546 } 547 return success; 548 } 549 550 static bool emulated_lock(const std::string& path) { 551 if (chmod(path.c_str(), 0000) != 0) { 552 PLOG(ERROR) << "Failed to chmod " << path; 553 return false; 554 } 555 #if EMULATED_USES_SELINUX 556 if (setfilecon(path.c_str(), "u:object_r:storage_stub_file:s0") != 0) { 557 PLOG(WARNING) << "Failed to setfilecon " << path; 558 return false; 559 } 560 #endif 561 return true; 562 } 563 564 static bool emulated_unlock(const std::string& path, mode_t mode) { 565 if (chmod(path.c_str(), mode) != 0) { 566 PLOG(ERROR) << "Failed to chmod " << path; 567 // FIXME temporary workaround for b/26713622 568 if (e4crypt_is_emulated()) return false; 569 } 570 #if EMULATED_USES_SELINUX 571 if (selinux_android_restorecon(path.c_str(), SELINUX_ANDROID_RESTORECON_FORCE) != 0) { 572 PLOG(WARNING) << "Failed to restorecon " << path; 573 // FIXME temporary workaround for b/26713622 574 if (e4crypt_is_emulated()) return false; 575 } 576 #endif 577 return true; 578 } 579 580 static bool parse_hex(const char* hex, std::string* result) { 581 if (strcmp("!", hex) == 0) { 582 *result = ""; 583 return true; 584 } 585 if (android::vold::HexToStr(hex, *result) != 0) { 586 LOG(ERROR) << "Invalid FBE hex string"; // Don't log the string for security reasons 587 return false; 588 } 589 return true; 590 } 591 592 bool e4crypt_add_user_key_auth(userid_t user_id, int serial, const char* token_hex, 593 const char* secret_hex) { 594 LOG(DEBUG) << "e4crypt_add_user_key_auth " << user_id << " serial=" << serial 595 << " token_present=" << (strcmp(token_hex, "!") != 0); 596 if (!e4crypt_is_native()) return true; 597 if (s_ephemeral_users.count(user_id) != 0) return true; 598 std::string token, secret; 599 if (!parse_hex(token_hex, &token)) return false; 600 if (!parse_hex(secret_hex, &secret)) return false; 601 auto auth = secret.empty() ? kEmptyAuthentication 602 : android::vold::KeyAuthentication(token, secret); 603 auto it = s_ce_keys.find(user_id); 604 if (it == s_ce_keys.end()) { 605 LOG(ERROR) << "Key not loaded into memory, can't change for user " << user_id; 606 return false; 607 } 608 auto ce_key = it->second; 609 auto const directory_path = get_ce_key_directory_path(user_id); 610 auto const paths = get_ce_key_paths(directory_path); 611 std::string ce_key_path; 612 if (!get_ce_key_new_path(directory_path, paths, &ce_key_path)) return false; 613 if (!store_key(ce_key_path, user_key_temp, auth, ce_key)) return false; 614 return true; 615 } 616 617 bool e4crypt_fixate_newest_user_key_auth(userid_t user_id) { 618 LOG(DEBUG) << "e4crypt_fixate_newest_user_key_auth " << user_id; 619 if (!e4crypt_is_native()) return true; 620 auto const directory_path = get_ce_key_directory_path(user_id); 621 auto const paths = get_ce_key_paths(directory_path); 622 if (paths.empty()) { 623 LOG(ERROR) << "No ce keys present, cannot fixate for user " << user_id; 624 return false; 625 } 626 fixate_user_ce_key(directory_path, paths[0], paths); 627 return true; 628 } 629 630 // TODO: rename to 'install' for consistency, and take flags to know which keys to install 631 bool e4crypt_unlock_user_key(userid_t user_id, int serial, const char* token_hex, 632 const char* secret_hex) { 633 LOG(DEBUG) << "e4crypt_unlock_user_key " << user_id << " serial=" << serial 634 << " token_present=" << (strcmp(token_hex, "!") != 0); 635 if (e4crypt_is_native()) { 636 if (s_ce_key_raw_refs.count(user_id) != 0) { 637 LOG(WARNING) << "Tried to unlock already-unlocked key for user " << user_id; 638 return true; 639 } 640 std::string token, secret; 641 if (!parse_hex(token_hex, &token)) return false; 642 if (!parse_hex(secret_hex, &secret)) return false; 643 android::vold::KeyAuthentication auth(token, secret); 644 if (!read_and_install_user_ce_key(user_id, auth)) { 645 LOG(ERROR) << "Couldn't read key for " << user_id; 646 return false; 647 } 648 } else { 649 // When in emulation mode, we just use chmod. However, we also 650 // unlock directories when not in emulation mode, to bring devices 651 // back into a known-good state. 652 if (!emulated_unlock(android::vold::BuildDataSystemCePath(user_id), 0771) || 653 !emulated_unlock(android::vold::BuildDataMiscCePath(user_id), 01771) || 654 !emulated_unlock(android::vold::BuildDataMediaCePath(nullptr, user_id), 0770) || 655 !emulated_unlock(android::vold::BuildDataUserCePath(nullptr, user_id), 0771)) { 656 LOG(ERROR) << "Failed to unlock user " << user_id; 657 return false; 658 } 659 } 660 return true; 661 } 662 663 // TODO: rename to 'evict' for consistency 664 bool e4crypt_lock_user_key(userid_t user_id) { 665 if (e4crypt_is_native()) { 666 // TODO: remove from kernel keyring 667 } else if (e4crypt_is_emulated()) { 668 // When in emulation mode, we just use chmod 669 if (!emulated_lock(android::vold::BuildDataSystemCePath(user_id)) || 670 !emulated_lock(android::vold::BuildDataMiscCePath(user_id)) || 671 !emulated_lock(android::vold::BuildDataMediaCePath(nullptr, user_id)) || 672 !emulated_lock(android::vold::BuildDataUserCePath(nullptr, user_id))) { 673 LOG(ERROR) << "Failed to lock user " << user_id; 674 return false; 675 } 676 } 677 678 return true; 679 } 680 681 bool e4crypt_prepare_user_storage(const char* volume_uuid, userid_t user_id, int serial, 682 int flags) { 683 LOG(DEBUG) << "e4crypt_prepare_user_storage for volume " << escape_null(volume_uuid) 684 << ", user " << user_id << ", serial " << serial << ", flags " << flags; 685 686 if (flags & FLAG_STORAGE_DE) { 687 // DE_sys key 688 auto system_legacy_path = android::vold::BuildDataSystemLegacyPath(user_id); 689 auto misc_legacy_path = android::vold::BuildDataMiscLegacyPath(user_id); 690 auto profiles_de_path = android::vold::BuildDataProfilesDePath(user_id); 691 auto foreign_de_path = android::vold::BuildDataProfilesForeignDexDePath(user_id); 692 693 // DE_n key 694 auto system_de_path = android::vold::BuildDataSystemDePath(user_id); 695 auto misc_de_path = android::vold::BuildDataMiscDePath(user_id); 696 auto user_de_path = android::vold::BuildDataUserDePath(volume_uuid, user_id); 697 698 if (!prepare_dir(system_legacy_path, 0700, AID_SYSTEM, AID_SYSTEM)) return false; 699 #if MANAGE_MISC_DIRS 700 if (!prepare_dir(misc_legacy_path, 0750, multiuser_get_uid(user_id, AID_SYSTEM), 701 multiuser_get_uid(user_id, AID_EVERYBODY))) return false; 702 #endif 703 if (!prepare_dir(profiles_de_path, 0771, AID_SYSTEM, AID_SYSTEM)) return false; 704 if (!prepare_dir(foreign_de_path, 0773, AID_SYSTEM, AID_SYSTEM)) return false; 705 706 if (!prepare_dir(system_de_path, 0770, AID_SYSTEM, AID_SYSTEM)) return false; 707 if (!prepare_dir(misc_de_path, 01771, AID_SYSTEM, AID_MISC)) return false; 708 if (!prepare_dir(user_de_path, 0771, AID_SYSTEM, AID_SYSTEM)) return false; 709 710 // For now, FBE is only supported on internal storage 711 if (e4crypt_is_native() && volume_uuid == nullptr) { 712 std::string de_raw_ref; 713 if (!lookup_key_ref(s_de_key_raw_refs, user_id, &de_raw_ref)) return false; 714 if (!ensure_policy(de_raw_ref, system_de_path)) return false; 715 if (!ensure_policy(de_raw_ref, misc_de_path)) return false; 716 if (!ensure_policy(de_raw_ref, user_de_path)) return false; 717 } 718 } 719 720 if (flags & FLAG_STORAGE_CE) { 721 // CE_n key 722 auto system_ce_path = android::vold::BuildDataSystemCePath(user_id); 723 auto misc_ce_path = android::vold::BuildDataMiscCePath(user_id); 724 auto media_ce_path = android::vold::BuildDataMediaCePath(volume_uuid, user_id); 725 auto user_ce_path = android::vold::BuildDataUserCePath(volume_uuid, user_id); 726 727 if (!prepare_dir(system_ce_path, 0770, AID_SYSTEM, AID_SYSTEM)) return false; 728 if (!prepare_dir(misc_ce_path, 01771, AID_SYSTEM, AID_MISC)) return false; 729 if (!prepare_dir(media_ce_path, 0770, AID_MEDIA_RW, AID_MEDIA_RW)) return false; 730 if (!prepare_dir(user_ce_path, 0771, AID_SYSTEM, AID_SYSTEM)) return false; 731 732 // For now, FBE is only supported on internal storage 733 if (e4crypt_is_native() && volume_uuid == nullptr) { 734 std::string ce_raw_ref; 735 if (!lookup_key_ref(s_ce_key_raw_refs, user_id, &ce_raw_ref)) return false; 736 if (!ensure_policy(ce_raw_ref, system_ce_path)) return false; 737 if (!ensure_policy(ce_raw_ref, misc_ce_path)) return false; 738 if (!ensure_policy(ce_raw_ref, media_ce_path)) return false; 739 if (!ensure_policy(ce_raw_ref, user_ce_path)) return false; 740 } 741 } 742 743 return true; 744 } 745 746 bool e4crypt_destroy_user_storage(const char* volume_uuid, userid_t user_id, int flags) { 747 LOG(DEBUG) << "e4crypt_destroy_user_storage for volume " << escape_null(volume_uuid) 748 << ", user " << user_id << ", flags " << flags; 749 bool res = true; 750 751 if (flags & FLAG_STORAGE_DE) { 752 // DE_sys key 753 auto system_legacy_path = android::vold::BuildDataSystemLegacyPath(user_id); 754 auto misc_legacy_path = android::vold::BuildDataMiscLegacyPath(user_id); 755 auto profiles_de_path = android::vold::BuildDataProfilesDePath(user_id); 756 auto foreign_de_path = android::vold::BuildDataProfilesForeignDexDePath(user_id); 757 758 // DE_n key 759 auto system_de_path = android::vold::BuildDataSystemDePath(user_id); 760 auto misc_de_path = android::vold::BuildDataMiscDePath(user_id); 761 auto user_de_path = android::vold::BuildDataUserDePath(volume_uuid, user_id); 762 763 if (volume_uuid == nullptr) { 764 res &= destroy_dir(system_legacy_path); 765 #if MANAGE_MISC_DIRS 766 res &= destroy_dir(misc_legacy_path); 767 #endif 768 res &= destroy_dir(profiles_de_path); 769 res &= destroy_dir(foreign_de_path); 770 res &= destroy_dir(system_de_path); 771 res &= destroy_dir(misc_de_path); 772 } 773 res &= destroy_dir(user_de_path); 774 } 775 776 if (flags & FLAG_STORAGE_CE) { 777 // CE_n key 778 auto system_ce_path = android::vold::BuildDataSystemCePath(user_id); 779 auto misc_ce_path = android::vold::BuildDataMiscCePath(user_id); 780 auto media_ce_path = android::vold::BuildDataMediaCePath(volume_uuid, user_id); 781 auto user_ce_path = android::vold::BuildDataUserCePath(volume_uuid, user_id); 782 783 if (volume_uuid == nullptr) { 784 res &= destroy_dir(system_ce_path); 785 res &= destroy_dir(misc_ce_path); 786 } 787 res &= destroy_dir(media_ce_path); 788 res &= destroy_dir(user_ce_path); 789 } 790 791 return res; 792 } 793
