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 "KeyUtil.h" 21 #include "Utils.h" 22 #include "VoldUtil.h" 23 24 #include <algorithm> 25 #include <map> 26 #include <set> 27 #include <sstream> 28 #include <string> 29 #include <vector> 30 31 #include <dirent.h> 32 #include <errno.h> 33 #include <fcntl.h> 34 #include <unistd.h> 35 #include <limits.h> 36 #include <selinux/android.h> 37 #include <sys/mount.h> 38 #include <sys/stat.h> 39 #include <sys/types.h> 40 41 #include <private/android_filesystem_config.h> 42 43 #include "android/os/IVold.h" 44 45 #include "cryptfs.h" 46 47 #define EMULATED_USES_SELINUX 0 48 #define MANAGE_MISC_DIRS 0 49 50 #include <cutils/fs.h> 51 #include <cutils/properties.h> 52 53 #include <ext4_utils/ext4_crypt.h> 54 #include <keyutils.h> 55 56 #include <android-base/file.h> 57 #include <android-base/logging.h> 58 #include <android-base/properties.h> 59 #include <android-base/stringprintf.h> 60 61 using android::base::StringPrintf; 62 using android::base::WriteStringToFile; 63 using android::vold::kEmptyAuthentication; 64 using android::vold::KeyBuffer; 65 66 namespace { 67 68 struct PolicyKeyRef { 69 std::string contents_mode; 70 std::string filenames_mode; 71 std::string key_raw_ref; 72 }; 73 74 const std::string device_key_dir = std::string() + DATA_MNT_POINT + e4crypt_unencrypted_folder; 75 const std::string device_key_path = device_key_dir + "/key"; 76 const std::string device_key_temp = device_key_dir + "/temp"; 77 78 const std::string user_key_dir = std::string() + DATA_MNT_POINT + "/misc/vold/user_keys"; 79 const std::string user_key_temp = user_key_dir + "/temp"; 80 const std::string prepare_subdirs_path = "/system/bin/vold_prepare_subdirs"; 81 82 const std::string systemwide_volume_key_dir = 83 std::string() + DATA_MNT_POINT + "/misc/vold/volume_keys"; 84 85 bool s_global_de_initialized = false; 86 87 // Some users are ephemeral, don't try to wipe their keys from disk 88 std::set<userid_t> s_ephemeral_users; 89 90 // Map user ids to key references 91 std::map<userid_t, std::string> s_de_key_raw_refs; 92 std::map<userid_t, std::string> s_ce_key_raw_refs; 93 // TODO abolish this map, per b/26948053 94 std::map<userid_t, KeyBuffer> s_ce_keys; 95 96 } 97 98 static bool e4crypt_is_emulated() { 99 return property_get_bool("persist.sys.emulate_fbe", false); 100 } 101 102 static const char* escape_empty(const std::string& value) { 103 return value.empty() ? "null" : value.c_str(); 104 } 105 106 static std::string get_de_key_path(userid_t user_id) { 107 return StringPrintf("%s/de/%d", user_key_dir.c_str(), user_id); 108 } 109 110 static std::string get_ce_key_directory_path(userid_t user_id) { 111 return StringPrintf("%s/ce/%d", user_key_dir.c_str(), user_id); 112 } 113 114 // Returns the keys newest first 115 static std::vector<std::string> get_ce_key_paths(const std::string& directory_path) { 116 auto dirp = std::unique_ptr<DIR, int (*)(DIR*)>(opendir(directory_path.c_str()), closedir); 117 if (!dirp) { 118 PLOG(ERROR) << "Unable to open ce key directory: " + directory_path; 119 return std::vector<std::string>(); 120 } 121 std::vector<std::string> result; 122 for (;;) { 123 errno = 0; 124 auto const entry = readdir(dirp.get()); 125 if (!entry) { 126 if (errno) { 127 PLOG(ERROR) << "Unable to read ce key directory: " + directory_path; 128 return std::vector<std::string>(); 129 } 130 break; 131 } 132 if (entry->d_type != DT_DIR || entry->d_name[0] != 'c') { 133 LOG(DEBUG) << "Skipping non-key " << entry->d_name; 134 continue; 135 } 136 result.emplace_back(directory_path + "/" + entry->d_name); 137 } 138 std::sort(result.begin(), result.end()); 139 std::reverse(result.begin(), result.end()); 140 return result; 141 } 142 143 static std::string get_ce_key_current_path(const std::string& directory_path) { 144 return directory_path + "/current"; 145 } 146 147 static bool get_ce_key_new_path(const std::string& directory_path, 148 const std::vector<std::string>& paths, 149 std::string *ce_key_path) { 150 if (paths.empty()) { 151 *ce_key_path = get_ce_key_current_path(directory_path); 152 return true; 153 } 154 for (unsigned int i = 0; i < UINT_MAX; i++) { 155 auto const candidate = StringPrintf("%s/cx%010u", directory_path.c_str(), i); 156 if (paths[0] < candidate) { 157 *ce_key_path = candidate; 158 return true; 159 } 160 } 161 return false; 162 } 163 164 // Discard all keys but the named one; rename it to canonical name. 165 // No point in acting on errors in this; ignore them. 166 static void fixate_user_ce_key(const std::string& directory_path, const std::string &to_fix, 167 const std::vector<std::string>& paths) { 168 for (auto const other_path: paths) { 169 if (other_path != to_fix) { 170 android::vold::destroyKey(other_path); 171 } 172 } 173 auto const current_path = get_ce_key_current_path(directory_path); 174 if (to_fix != current_path) { 175 LOG(DEBUG) << "Renaming " << to_fix << " to " << current_path; 176 if (rename(to_fix.c_str(), current_path.c_str()) != 0) { 177 PLOG(WARNING) << "Unable to rename " << to_fix << " to " << current_path; 178 } 179 } 180 } 181 182 static bool read_and_fixate_user_ce_key(userid_t user_id, 183 const android::vold::KeyAuthentication& auth, 184 KeyBuffer *ce_key) { 185 auto const directory_path = get_ce_key_directory_path(user_id); 186 auto const paths = get_ce_key_paths(directory_path); 187 for (auto const ce_key_path: paths) { 188 LOG(DEBUG) << "Trying user CE key " << ce_key_path; 189 if (android::vold::retrieveKey(ce_key_path, auth, ce_key)) { 190 LOG(DEBUG) << "Successfully retrieved key"; 191 fixate_user_ce_key(directory_path, ce_key_path, paths); 192 return true; 193 } 194 } 195 LOG(ERROR) << "Failed to find working ce key for user " << user_id; 196 return false; 197 } 198 199 static bool read_and_install_user_ce_key(userid_t user_id, 200 const android::vold::KeyAuthentication& auth) { 201 if (s_ce_key_raw_refs.count(user_id) != 0) return true; 202 KeyBuffer ce_key; 203 if (!read_and_fixate_user_ce_key(user_id, auth, &ce_key)) return false; 204 std::string ce_raw_ref; 205 if (!android::vold::installKey(ce_key, &ce_raw_ref)) return false; 206 s_ce_keys[user_id] = std::move(ce_key); 207 s_ce_key_raw_refs[user_id] = ce_raw_ref; 208 LOG(DEBUG) << "Installed ce key for user " << user_id; 209 return true; 210 } 211 212 static bool prepare_dir(const std::string& dir, mode_t mode, uid_t uid, gid_t gid) { 213 LOG(DEBUG) << "Preparing: " << dir; 214 if (fs_prepare_dir(dir.c_str(), mode, uid, gid) != 0) { 215 PLOG(ERROR) << "Failed to prepare " << dir; 216 return false; 217 } 218 return true; 219 } 220 221 static bool destroy_dir(const std::string& dir) { 222 LOG(DEBUG) << "Destroying: " << dir; 223 if (rmdir(dir.c_str()) != 0 && errno != ENOENT) { 224 PLOG(ERROR) << "Failed to destroy " << dir; 225 return false; 226 } 227 return true; 228 } 229 230 // NB this assumes that there is only one thread listening for crypt commands, because 231 // it creates keys in a fixed location. 232 static bool create_and_install_user_keys(userid_t user_id, bool create_ephemeral) { 233 KeyBuffer de_key, ce_key; 234 if (!android::vold::randomKey(&de_key)) return false; 235 if (!android::vold::randomKey(&ce_key)) return false; 236 if (create_ephemeral) { 237 // If the key should be created as ephemeral, don't store it. 238 s_ephemeral_users.insert(user_id); 239 } else { 240 auto const directory_path = get_ce_key_directory_path(user_id); 241 if (!prepare_dir(directory_path, 0700, AID_ROOT, AID_ROOT)) return false; 242 auto const paths = get_ce_key_paths(directory_path); 243 std::string ce_key_path; 244 if (!get_ce_key_new_path(directory_path, paths, &ce_key_path)) return false; 245 if (!android::vold::storeKeyAtomically(ce_key_path, user_key_temp, 246 kEmptyAuthentication, ce_key)) return false; 247 fixate_user_ce_key(directory_path, ce_key_path, paths); 248 // Write DE key second; once this is written, all is good. 249 if (!android::vold::storeKeyAtomically(get_de_key_path(user_id), user_key_temp, 250 kEmptyAuthentication, de_key)) return false; 251 } 252 std::string de_raw_ref; 253 if (!android::vold::installKey(de_key, &de_raw_ref)) return false; 254 s_de_key_raw_refs[user_id] = de_raw_ref; 255 std::string ce_raw_ref; 256 if (!android::vold::installKey(ce_key, &ce_raw_ref)) return false; 257 s_ce_keys[user_id] = ce_key; 258 s_ce_key_raw_refs[user_id] = ce_raw_ref; 259 LOG(DEBUG) << "Created keys for user " << user_id; 260 return true; 261 } 262 263 static bool lookup_key_ref(const std::map<userid_t, std::string>& key_map, userid_t user_id, 264 std::string* raw_ref) { 265 auto refi = key_map.find(user_id); 266 if (refi == key_map.end()) { 267 LOG(ERROR) << "Cannot find key for " << user_id; 268 return false; 269 } 270 *raw_ref = refi->second; 271 return true; 272 } 273 274 static void get_data_file_encryption_modes(PolicyKeyRef* key_ref) { 275 struct fstab_rec* rec = fs_mgr_get_entry_for_mount_point(fstab_default, DATA_MNT_POINT); 276 char const* contents_mode; 277 char const* filenames_mode; 278 fs_mgr_get_file_encryption_modes(rec, &contents_mode, &filenames_mode); 279 key_ref->contents_mode = contents_mode; 280 key_ref->filenames_mode = filenames_mode; 281 } 282 283 static bool ensure_policy(const PolicyKeyRef& key_ref, const std::string& path) { 284 return e4crypt_policy_ensure(path.c_str(), key_ref.key_raw_ref.data(), 285 key_ref.key_raw_ref.size(), key_ref.contents_mode.c_str(), 286 key_ref.filenames_mode.c_str()) == 0; 287 } 288 289 static bool is_numeric(const char* name) { 290 for (const char* p = name; *p != '\0'; p++) { 291 if (!isdigit(*p)) return false; 292 } 293 return true; 294 } 295 296 static bool load_all_de_keys() { 297 auto de_dir = user_key_dir + "/de"; 298 auto dirp = std::unique_ptr<DIR, int (*)(DIR*)>(opendir(de_dir.c_str()), closedir); 299 if (!dirp) { 300 PLOG(ERROR) << "Unable to read de key directory"; 301 return false; 302 } 303 for (;;) { 304 errno = 0; 305 auto entry = readdir(dirp.get()); 306 if (!entry) { 307 if (errno) { 308 PLOG(ERROR) << "Unable to read de key directory"; 309 return false; 310 } 311 break; 312 } 313 if (entry->d_type != DT_DIR || !is_numeric(entry->d_name)) { 314 LOG(DEBUG) << "Skipping non-de-key " << entry->d_name; 315 continue; 316 } 317 userid_t user_id = std::stoi(entry->d_name); 318 if (s_de_key_raw_refs.count(user_id) == 0) { 319 auto key_path = de_dir + "/" + entry->d_name; 320 KeyBuffer key; 321 if (!android::vold::retrieveKey(key_path, kEmptyAuthentication, &key)) return false; 322 std::string raw_ref; 323 if (!android::vold::installKey(key, &raw_ref)) return false; 324 s_de_key_raw_refs[user_id] = raw_ref; 325 LOG(DEBUG) << "Installed de key for user " << user_id; 326 } 327 } 328 // ext4enc:TODO: go through all DE directories, ensure that all user dirs have the 329 // correct policy set on them, and that no rogue ones exist. 330 return true; 331 } 332 333 bool e4crypt_initialize_global_de() { 334 LOG(INFO) << "e4crypt_initialize_global_de"; 335 336 if (s_global_de_initialized) { 337 LOG(INFO) << "Already initialized"; 338 return true; 339 } 340 341 PolicyKeyRef device_ref; 342 if (!android::vold::retrieveAndInstallKey(true, kEmptyAuthentication, device_key_path, 343 device_key_temp, &device_ref.key_raw_ref)) 344 return false; 345 get_data_file_encryption_modes(&device_ref); 346 347 std::string modestring = device_ref.contents_mode + ":" + device_ref.filenames_mode; 348 std::string mode_filename = std::string("/data") + e4crypt_key_mode; 349 if (!android::base::WriteStringToFile(modestring, mode_filename)) { 350 PLOG(ERROR) << "Cannot save type"; 351 return false; 352 } 353 354 std::string ref_filename = std::string("/data") + e4crypt_key_ref; 355 if (!android::base::WriteStringToFile(device_ref.key_raw_ref, ref_filename)) { 356 PLOG(ERROR) << "Cannot save key reference to:" << ref_filename; 357 return false; 358 } 359 LOG(INFO) << "Wrote system DE key reference to:" << ref_filename; 360 361 s_global_de_initialized = true; 362 return true; 363 } 364 365 bool e4crypt_init_user0() { 366 LOG(DEBUG) << "e4crypt_init_user0"; 367 if (e4crypt_is_native()) { 368 if (!prepare_dir(user_key_dir, 0700, AID_ROOT, AID_ROOT)) return false; 369 if (!prepare_dir(user_key_dir + "/ce", 0700, AID_ROOT, AID_ROOT)) return false; 370 if (!prepare_dir(user_key_dir + "/de", 0700, AID_ROOT, AID_ROOT)) return false; 371 if (!android::vold::pathExists(get_de_key_path(0))) { 372 if (!create_and_install_user_keys(0, false)) return false; 373 } 374 // TODO: switch to loading only DE_0 here once framework makes 375 // explicit calls to install DE keys for secondary users 376 if (!load_all_de_keys()) return false; 377 } 378 // We can only safely prepare DE storage here, since CE keys are probably 379 // entangled with user credentials. The framework will always prepare CE 380 // storage once CE keys are installed. 381 if (!e4crypt_prepare_user_storage("", 0, 0, android::os::IVold::STORAGE_FLAG_DE)) { 382 LOG(ERROR) << "Failed to prepare user 0 storage"; 383 return false; 384 } 385 386 // If this is a non-FBE device that recently left an emulated mode, 387 // restore user data directories to known-good state. 388 if (!e4crypt_is_native() && !e4crypt_is_emulated()) { 389 e4crypt_unlock_user_key(0, 0, "!", "!"); 390 } 391 392 return true; 393 } 394 395 bool e4crypt_vold_create_user_key(userid_t user_id, int serial, bool ephemeral) { 396 LOG(DEBUG) << "e4crypt_vold_create_user_key for " << user_id << " serial " << serial; 397 if (!e4crypt_is_native()) { 398 return true; 399 } 400 // FIXME test for existence of key that is not loaded yet 401 if (s_ce_key_raw_refs.count(user_id) != 0) { 402 LOG(ERROR) << "Already exists, can't e4crypt_vold_create_user_key for " << user_id 403 << " serial " << serial; 404 // FIXME should we fail the command? 405 return true; 406 } 407 if (!create_and_install_user_keys(user_id, ephemeral)) { 408 return false; 409 } 410 return true; 411 } 412 413 static void drop_caches() { 414 // Clean any dirty pages (otherwise they won't be dropped). 415 sync(); 416 // Drop inode and page caches. 417 if (!WriteStringToFile("3", "/proc/sys/vm/drop_caches")) { 418 PLOG(ERROR) << "Failed to drop caches during key eviction"; 419 } 420 } 421 422 static bool evict_ce_key(userid_t user_id) { 423 s_ce_keys.erase(user_id); 424 bool success = true; 425 std::string raw_ref; 426 // If we haven't loaded the CE key, no need to evict it. 427 if (lookup_key_ref(s_ce_key_raw_refs, user_id, &raw_ref)) { 428 success &= android::vold::evictKey(raw_ref); 429 drop_caches(); 430 } 431 s_ce_key_raw_refs.erase(user_id); 432 return success; 433 } 434 435 bool e4crypt_destroy_user_key(userid_t user_id) { 436 LOG(DEBUG) << "e4crypt_destroy_user_key(" << user_id << ")"; 437 if (!e4crypt_is_native()) { 438 return true; 439 } 440 bool success = true; 441 std::string raw_ref; 442 success &= evict_ce_key(user_id); 443 success &= lookup_key_ref(s_de_key_raw_refs, user_id, &raw_ref) 444 && android::vold::evictKey(raw_ref); 445 s_de_key_raw_refs.erase(user_id); 446 auto it = s_ephemeral_users.find(user_id); 447 if (it != s_ephemeral_users.end()) { 448 s_ephemeral_users.erase(it); 449 } else { 450 for (auto const path: get_ce_key_paths(get_ce_key_directory_path(user_id))) { 451 success &= android::vold::destroyKey(path); 452 } 453 auto de_key_path = get_de_key_path(user_id); 454 if (android::vold::pathExists(de_key_path)) { 455 success &= android::vold::destroyKey(de_key_path); 456 } else { 457 LOG(INFO) << "Not present so not erasing: " << de_key_path; 458 } 459 } 460 return success; 461 } 462 463 static bool emulated_lock(const std::string& path) { 464 if (chmod(path.c_str(), 0000) != 0) { 465 PLOG(ERROR) << "Failed to chmod " << path; 466 return false; 467 } 468 #if EMULATED_USES_SELINUX 469 if (setfilecon(path.c_str(), "u:object_r:storage_stub_file:s0") != 0) { 470 PLOG(WARNING) << "Failed to setfilecon " << path; 471 return false; 472 } 473 #endif 474 return true; 475 } 476 477 static bool emulated_unlock(const std::string& path, mode_t mode) { 478 if (chmod(path.c_str(), mode) != 0) { 479 PLOG(ERROR) << "Failed to chmod " << path; 480 // FIXME temporary workaround for b/26713622 481 if (e4crypt_is_emulated()) return false; 482 } 483 #if EMULATED_USES_SELINUX 484 if (selinux_android_restorecon(path.c_str(), SELINUX_ANDROID_RESTORECON_FORCE) != 0) { 485 PLOG(WARNING) << "Failed to restorecon " << path; 486 // FIXME temporary workaround for b/26713622 487 if (e4crypt_is_emulated()) return false; 488 } 489 #endif 490 return true; 491 } 492 493 static bool parse_hex(const std::string& hex, std::string* result) { 494 if (hex == "!") { 495 *result = ""; 496 return true; 497 } 498 if (android::vold::HexToStr(hex, *result) != 0) { 499 LOG(ERROR) << "Invalid FBE hex string"; // Don't log the string for security reasons 500 return false; 501 } 502 return true; 503 } 504 505 static std::string volkey_path(const std::string& misc_path, const std::string& volume_uuid) { 506 return misc_path + "/vold/volume_keys/" + volume_uuid + "/default"; 507 } 508 509 static std::string volume_secdiscardable_path(const std::string& volume_uuid) { 510 return systemwide_volume_key_dir + "/" + volume_uuid + "/secdiscardable"; 511 } 512 513 static bool read_or_create_volkey(const std::string& misc_path, const std::string& volume_uuid, 514 PolicyKeyRef* key_ref) { 515 auto secdiscardable_path = volume_secdiscardable_path(volume_uuid); 516 std::string secdiscardable_hash; 517 if (android::vold::pathExists(secdiscardable_path)) { 518 if (!android::vold::readSecdiscardable(secdiscardable_path, &secdiscardable_hash)) 519 return false; 520 } else { 521 if (fs_mkdirs(secdiscardable_path.c_str(), 0700) != 0) { 522 PLOG(ERROR) << "Creating directories for: " << secdiscardable_path; 523 return false; 524 } 525 if (!android::vold::createSecdiscardable(secdiscardable_path, &secdiscardable_hash)) 526 return false; 527 } 528 auto key_path = volkey_path(misc_path, volume_uuid); 529 if (fs_mkdirs(key_path.c_str(), 0700) != 0) { 530 PLOG(ERROR) << "Creating directories for: " << key_path; 531 return false; 532 } 533 android::vold::KeyAuthentication auth("", secdiscardable_hash); 534 if (!android::vold::retrieveAndInstallKey(true, auth, key_path, key_path + "_tmp", 535 &key_ref->key_raw_ref)) 536 return false; 537 key_ref->contents_mode = 538 android::base::GetProperty("ro.crypto.volume.contents_mode", "aes-256-xts"); 539 key_ref->filenames_mode = 540 android::base::GetProperty("ro.crypto.volume.filenames_mode", "aes-256-heh"); 541 return true; 542 } 543 544 static bool destroy_volkey(const std::string& misc_path, const std::string& volume_uuid) { 545 auto path = volkey_path(misc_path, volume_uuid); 546 if (!android::vold::pathExists(path)) return true; 547 return android::vold::destroyKey(path); 548 } 549 550 bool e4crypt_add_user_key_auth(userid_t user_id, int serial, const std::string& token_hex, 551 const std::string& secret_hex) { 552 LOG(DEBUG) << "e4crypt_add_user_key_auth " << user_id << " serial=" << serial 553 << " token_present=" << (token_hex != "!"); 554 if (!e4crypt_is_native()) return true; 555 if (s_ephemeral_users.count(user_id) != 0) return true; 556 std::string token, secret; 557 if (!parse_hex(token_hex, &token)) return false; 558 if (!parse_hex(secret_hex, &secret)) return false; 559 auto auth = secret.empty() ? kEmptyAuthentication 560 : android::vold::KeyAuthentication(token, secret); 561 auto it = s_ce_keys.find(user_id); 562 if (it == s_ce_keys.end()) { 563 LOG(ERROR) << "Key not loaded into memory, can't change for user " << user_id; 564 return false; 565 } 566 const auto &ce_key = it->second; 567 auto const directory_path = get_ce_key_directory_path(user_id); 568 auto const paths = get_ce_key_paths(directory_path); 569 std::string ce_key_path; 570 if (!get_ce_key_new_path(directory_path, paths, &ce_key_path)) return false; 571 if (!android::vold::storeKeyAtomically(ce_key_path, user_key_temp, auth, ce_key)) return false; 572 return true; 573 } 574 575 bool e4crypt_fixate_newest_user_key_auth(userid_t user_id) { 576 LOG(DEBUG) << "e4crypt_fixate_newest_user_key_auth " << user_id; 577 if (!e4crypt_is_native()) return true; 578 if (s_ephemeral_users.count(user_id) != 0) return true; 579 auto const directory_path = get_ce_key_directory_path(user_id); 580 auto const paths = get_ce_key_paths(directory_path); 581 if (paths.empty()) { 582 LOG(ERROR) << "No ce keys present, cannot fixate for user " << user_id; 583 return false; 584 } 585 fixate_user_ce_key(directory_path, paths[0], paths); 586 return true; 587 } 588 589 // TODO: rename to 'install' for consistency, and take flags to know which keys to install 590 bool e4crypt_unlock_user_key(userid_t user_id, int serial, const std::string& token_hex, 591 const std::string& secret_hex) { 592 LOG(DEBUG) << "e4crypt_unlock_user_key " << user_id << " serial=" << serial 593 << " token_present=" << (token_hex != "!"); 594 if (e4crypt_is_native()) { 595 if (s_ce_key_raw_refs.count(user_id) != 0) { 596 LOG(WARNING) << "Tried to unlock already-unlocked key for user " << user_id; 597 return true; 598 } 599 std::string token, secret; 600 if (!parse_hex(token_hex, &token)) return false; 601 if (!parse_hex(secret_hex, &secret)) return false; 602 android::vold::KeyAuthentication auth(token, secret); 603 if (!read_and_install_user_ce_key(user_id, auth)) { 604 LOG(ERROR) << "Couldn't read key for " << user_id; 605 return false; 606 } 607 } else { 608 // When in emulation mode, we just use chmod. However, we also 609 // unlock directories when not in emulation mode, to bring devices 610 // back into a known-good state. 611 if (!emulated_unlock(android::vold::BuildDataSystemCePath(user_id), 0771) || 612 !emulated_unlock(android::vold::BuildDataMiscCePath(user_id), 01771) || 613 !emulated_unlock(android::vold::BuildDataMediaCePath("", user_id), 0770) || 614 !emulated_unlock(android::vold::BuildDataUserCePath("", user_id), 0771)) { 615 LOG(ERROR) << "Failed to unlock user " << user_id; 616 return false; 617 } 618 } 619 return true; 620 } 621 622 // TODO: rename to 'evict' for consistency 623 bool e4crypt_lock_user_key(userid_t user_id) { 624 LOG(DEBUG) << "e4crypt_lock_user_key " << user_id; 625 if (e4crypt_is_native()) { 626 return evict_ce_key(user_id); 627 } else if (e4crypt_is_emulated()) { 628 // When in emulation mode, we just use chmod 629 if (!emulated_lock(android::vold::BuildDataSystemCePath(user_id)) || 630 !emulated_lock(android::vold::BuildDataMiscCePath(user_id)) || 631 !emulated_lock(android::vold::BuildDataMediaCePath("", user_id)) || 632 !emulated_lock(android::vold::BuildDataUserCePath("", user_id))) { 633 LOG(ERROR) << "Failed to lock user " << user_id; 634 return false; 635 } 636 } 637 638 return true; 639 } 640 641 static bool prepare_subdirs(const std::string& action, const std::string& volume_uuid, 642 userid_t user_id, int flags) { 643 if (0 != android::vold::ForkExecvp( 644 std::vector<std::string>{prepare_subdirs_path, action, volume_uuid, 645 std::to_string(user_id), std::to_string(flags)})) { 646 LOG(ERROR) << "vold_prepare_subdirs failed"; 647 return false; 648 } 649 return true; 650 } 651 652 bool e4crypt_prepare_user_storage(const std::string& volume_uuid, userid_t user_id, int serial, 653 int flags) { 654 LOG(DEBUG) << "e4crypt_prepare_user_storage for volume " << escape_empty(volume_uuid) 655 << ", user " << user_id << ", serial " << serial << ", flags " << flags; 656 657 if (flags & android::os::IVold::STORAGE_FLAG_DE) { 658 // DE_sys key 659 auto system_legacy_path = android::vold::BuildDataSystemLegacyPath(user_id); 660 auto misc_legacy_path = android::vold::BuildDataMiscLegacyPath(user_id); 661 auto profiles_de_path = android::vold::BuildDataProfilesDePath(user_id); 662 663 // DE_n key 664 auto system_de_path = android::vold::BuildDataSystemDePath(user_id); 665 auto misc_de_path = android::vold::BuildDataMiscDePath(user_id); 666 auto vendor_de_path = android::vold::BuildDataVendorDePath(user_id); 667 auto user_de_path = android::vold::BuildDataUserDePath(volume_uuid, user_id); 668 669 if (volume_uuid.empty()) { 670 if (!prepare_dir(system_legacy_path, 0700, AID_SYSTEM, AID_SYSTEM)) return false; 671 #if MANAGE_MISC_DIRS 672 if (!prepare_dir(misc_legacy_path, 0750, multiuser_get_uid(user_id, AID_SYSTEM), 673 multiuser_get_uid(user_id, AID_EVERYBODY))) return false; 674 #endif 675 if (!prepare_dir(profiles_de_path, 0771, AID_SYSTEM, AID_SYSTEM)) return false; 676 677 if (!prepare_dir(system_de_path, 0770, AID_SYSTEM, AID_SYSTEM)) return false; 678 if (!prepare_dir(misc_de_path, 01771, AID_SYSTEM, AID_MISC)) return false; 679 if (!prepare_dir(vendor_de_path, 0771, AID_ROOT, AID_ROOT)) return false; 680 } 681 if (!prepare_dir(user_de_path, 0771, AID_SYSTEM, AID_SYSTEM)) return false; 682 683 if (e4crypt_is_native()) { 684 PolicyKeyRef de_ref; 685 if (volume_uuid.empty()) { 686 if (!lookup_key_ref(s_de_key_raw_refs, user_id, &de_ref.key_raw_ref)) return false; 687 get_data_file_encryption_modes(&de_ref); 688 if (!ensure_policy(de_ref, system_de_path)) return false; 689 if (!ensure_policy(de_ref, misc_de_path)) return false; 690 if (!ensure_policy(de_ref, vendor_de_path)) return false; 691 } else { 692 if (!read_or_create_volkey(misc_de_path, volume_uuid, &de_ref)) return false; 693 } 694 if (!ensure_policy(de_ref, user_de_path)) return false; 695 } 696 } 697 698 if (flags & android::os::IVold::STORAGE_FLAG_CE) { 699 // CE_n key 700 auto system_ce_path = android::vold::BuildDataSystemCePath(user_id); 701 auto misc_ce_path = android::vold::BuildDataMiscCePath(user_id); 702 auto vendor_ce_path = android::vold::BuildDataVendorCePath(user_id); 703 auto media_ce_path = android::vold::BuildDataMediaCePath(volume_uuid, user_id); 704 auto user_ce_path = android::vold::BuildDataUserCePath(volume_uuid, user_id); 705 706 if (volume_uuid.empty()) { 707 if (!prepare_dir(system_ce_path, 0770, AID_SYSTEM, AID_SYSTEM)) return false; 708 if (!prepare_dir(misc_ce_path, 01771, AID_SYSTEM, AID_MISC)) return false; 709 if (!prepare_dir(vendor_ce_path, 0771, AID_ROOT, AID_ROOT)) return false; 710 } 711 if (!prepare_dir(media_ce_path, 0770, AID_MEDIA_RW, AID_MEDIA_RW)) return false; 712 if (!prepare_dir(user_ce_path, 0771, AID_SYSTEM, AID_SYSTEM)) return false; 713 714 if (e4crypt_is_native()) { 715 PolicyKeyRef ce_ref; 716 if (volume_uuid.empty()) { 717 if (!lookup_key_ref(s_ce_key_raw_refs, user_id, &ce_ref.key_raw_ref)) return false; 718 get_data_file_encryption_modes(&ce_ref); 719 if (!ensure_policy(ce_ref, system_ce_path)) return false; 720 if (!ensure_policy(ce_ref, misc_ce_path)) return false; 721 if (!ensure_policy(ce_ref, vendor_ce_path)) return false; 722 723 } else { 724 if (!read_or_create_volkey(misc_ce_path, volume_uuid, &ce_ref)) return false; 725 } 726 if (!ensure_policy(ce_ref, media_ce_path)) return false; 727 if (!ensure_policy(ce_ref, user_ce_path)) return false; 728 } 729 730 if (volume_uuid.empty()) { 731 // Now that credentials have been installed, we can run restorecon 732 // over these paths 733 // NOTE: these paths need to be kept in sync with libselinux 734 android::vold::RestoreconRecursive(system_ce_path); 735 android::vold::RestoreconRecursive(misc_ce_path); 736 } 737 } 738 if (!prepare_subdirs("prepare", volume_uuid, user_id, flags)) return false; 739 740 return true; 741 } 742 743 bool e4crypt_destroy_user_storage(const std::string& volume_uuid, userid_t user_id, int flags) { 744 LOG(DEBUG) << "e4crypt_destroy_user_storage for volume " << escape_empty(volume_uuid) 745 << ", user " << user_id << ", flags " << flags; 746 bool res = true; 747 748 res &= prepare_subdirs("destroy", volume_uuid, user_id, flags); 749 750 if (flags & android::os::IVold::STORAGE_FLAG_CE) { 751 // CE_n key 752 auto system_ce_path = android::vold::BuildDataSystemCePath(user_id); 753 auto misc_ce_path = android::vold::BuildDataMiscCePath(user_id); 754 auto vendor_ce_path = android::vold::BuildDataVendorCePath(user_id); 755 auto media_ce_path = android::vold::BuildDataMediaCePath(volume_uuid, user_id); 756 auto user_ce_path = android::vold::BuildDataUserCePath(volume_uuid, user_id); 757 758 res &= destroy_dir(media_ce_path); 759 res &= destroy_dir(user_ce_path); 760 if (volume_uuid.empty()) { 761 res &= destroy_dir(system_ce_path); 762 res &= destroy_dir(misc_ce_path); 763 res &= destroy_dir(vendor_ce_path); 764 } else { 765 if (e4crypt_is_native()) { 766 res &= destroy_volkey(misc_ce_path, volume_uuid); 767 } 768 } 769 } 770 771 if (flags & android::os::IVold::STORAGE_FLAG_DE) { 772 // DE_sys key 773 auto system_legacy_path = android::vold::BuildDataSystemLegacyPath(user_id); 774 auto misc_legacy_path = android::vold::BuildDataMiscLegacyPath(user_id); 775 auto profiles_de_path = android::vold::BuildDataProfilesDePath(user_id); 776 777 // DE_n key 778 auto system_de_path = android::vold::BuildDataSystemDePath(user_id); 779 auto misc_de_path = android::vold::BuildDataMiscDePath(user_id); 780 auto vendor_de_path = android::vold::BuildDataVendorDePath(user_id); 781 auto user_de_path = android::vold::BuildDataUserDePath(volume_uuid, user_id); 782 783 res &= destroy_dir(user_de_path); 784 if (volume_uuid.empty()) { 785 res &= destroy_dir(system_legacy_path); 786 #if MANAGE_MISC_DIRS 787 res &= destroy_dir(misc_legacy_path); 788 #endif 789 res &= destroy_dir(profiles_de_path); 790 res &= destroy_dir(system_de_path); 791 res &= destroy_dir(misc_de_path); 792 res &= destroy_dir(vendor_de_path); 793 } else { 794 if (e4crypt_is_native()) { 795 res &= destroy_volkey(misc_de_path, volume_uuid); 796 } 797 } 798 } 799 800 return res; 801 } 802 803 static bool destroy_volume_keys(const std::string& directory_path, const std::string& volume_uuid) { 804 auto dirp = std::unique_ptr<DIR, int (*)(DIR*)>(opendir(directory_path.c_str()), closedir); 805 if (!dirp) { 806 PLOG(ERROR) << "Unable to open directory: " + directory_path; 807 return false; 808 } 809 bool res = true; 810 for (;;) { 811 errno = 0; 812 auto const entry = readdir(dirp.get()); 813 if (!entry) { 814 if (errno) { 815 PLOG(ERROR) << "Unable to read directory: " + directory_path; 816 return false; 817 } 818 break; 819 } 820 if (entry->d_type != DT_DIR || entry->d_name[0] == '.') { 821 LOG(DEBUG) << "Skipping non-user " << entry->d_name; 822 continue; 823 } 824 res &= destroy_volkey(directory_path + "/" + entry->d_name, volume_uuid); 825 } 826 return res; 827 } 828 829 bool e4crypt_destroy_volume_keys(const std::string& volume_uuid) { 830 bool res = true; 831 LOG(DEBUG) << "e4crypt_destroy_volume_keys for volume " << escape_empty(volume_uuid); 832 auto secdiscardable_path = volume_secdiscardable_path(volume_uuid); 833 res &= android::vold::runSecdiscardSingle(secdiscardable_path); 834 res &= destroy_volume_keys("/data/misc_ce", volume_uuid); 835 res &= destroy_volume_keys("/data/misc_de", volume_uuid); 836 return res; 837 } 838
