| /* |
| * Copyright (C) 2015 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "FsCrypt.h" |
| |
| #include "KeyStorage.h" |
| #include "KeyUtil.h" |
| #include "Utils.h" |
| #include "VoldUtil.h" |
| |
| #include <algorithm> |
| #include <map> |
| #include <optional> |
| #include <set> |
| #include <sstream> |
| #include <string> |
| #include <vector> |
| |
| #include <dirent.h> |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <limits.h> |
| #include <selinux/android.h> |
| #include <sys/mount.h> |
| #include <sys/stat.h> |
| #include <sys/types.h> |
| #include <unistd.h> |
| |
| #include <private/android_filesystem_config.h> |
| #include <private/android_projectid_config.h> |
| |
| #include "android/os/IVold.h" |
| |
| #define EMULATED_USES_SELINUX 0 |
| #define MANAGE_MISC_DIRS 0 |
| |
| #include <cutils/fs.h> |
| #include <cutils/properties.h> |
| |
| #include <fscrypt/fscrypt.h> |
| #include <keyutils.h> |
| #include <libdm/dm.h> |
| |
| #include <android-base/file.h> |
| #include <android-base/logging.h> |
| #include <android-base/properties.h> |
| #include <android-base/stringprintf.h> |
| #include <android-base/strings.h> |
| #include <android-base/unique_fd.h> |
| |
| #include "fscrypt-common.h" |
| |
| using android::base::Basename; |
| using android::base::Realpath; |
| using android::base::StartsWith; |
| using android::base::StringPrintf; |
| using android::fs_mgr::GetEntryForMountPoint; |
| using ::BuildDataPath; |
| using ::IsFilesystemSupported; |
| using ::kEmptyAuthentication; |
| using ::KeyBuffer; |
| using ::KeyGeneration; |
| using ::retrieveKey; |
| using ::retrieveOrGenerateKey; |
| using ::SetQuotaInherit; |
| using ::SetQuotaProjectId; |
| using ::writeStringToFile; |
| using namespace android::fscrypt; |
| using namespace android::dm; |
| |
| // Map user ids to encryption policies |
| std::map<userid_t, EncryptionPolicy> s_de_policies; |
| std::map<userid_t, EncryptionPolicy> s_ce_policies; |
| std::string de_key_raw_ref; |
| |
| namespace { |
| |
| const std::string device_key_dir = std::string() + DATA_MNT_POINT + fscrypt_unencrypted_folder; |
| const std::string device_key_path = device_key_dir + "/key"; |
| const std::string device_key_temp = device_key_dir + "/temp"; |
| |
| const std::string user_key_dir = std::string() + DATA_MNT_POINT + "/misc/vold/user_keys"; |
| const std::string user_key_temp = user_key_dir + "/temp"; |
| const std::string prepare_subdirs_path = "/system/bin/vold_prepare_subdirs"; |
| |
| const std::string systemwide_volume_key_dir = |
| std::string() + DATA_MNT_POINT + "/misc/vold/volume_keys"; |
| |
| // Some users are ephemeral, don't try to wipe their keys from disk |
| std::set<userid_t> s_ephemeral_users; |
| |
| } // namespace |
| |
| // Returns KeyGeneration suitable for key as described in EncryptionOptions |
| static KeyGeneration makeGen(const EncryptionOptions& options) { |
| return KeyGeneration{FSCRYPT_MAX_KEY_SIZE, true, options.use_hw_wrapped_key}; |
| } |
| |
| static bool fscrypt_is_emulated() { |
| return property_get_bool("persist.sys.emulate_fbe", false); |
| } |
| |
| static const char* escape_empty(const std::string& value) { |
| return value.empty() ? "null" : value.c_str(); |
| } |
| |
| static std::string get_de_key_path(userid_t user_id) { |
| return StringPrintf("%s/de/%d", user_key_dir.c_str(), user_id); |
| } |
| |
| static std::string get_ce_key_directory_path(userid_t user_id) { |
| return StringPrintf("%s/ce/%d", user_key_dir.c_str(), user_id); |
| } |
| |
| // Returns the keys newest first |
| static std::vector<std::string> get_ce_key_paths(const std::string& directory_path) { |
| auto dirp = std::unique_ptr<DIR, int (*)(DIR*)>(opendir(directory_path.c_str()), closedir); |
| if (!dirp) { |
| PLOG(ERROR) << "Unable to open ce key directory: " + directory_path; |
| return std::vector<std::string>(); |
| } |
| std::vector<std::string> result; |
| for (;;) { |
| errno = 0; |
| auto const entry = readdir(dirp.get()); |
| if (!entry) { |
| if (errno) { |
| PLOG(ERROR) << "Unable to read ce key directory: " + directory_path; |
| return std::vector<std::string>(); |
| } |
| break; |
| } |
| if (entry->d_type != DT_DIR || entry->d_name[0] != 'c') { |
| LOG(INFO) << "Skipping non-key " << entry->d_name; |
| continue; |
| } |
| result.emplace_back(directory_path + "/" + entry->d_name); |
| } |
| std::sort(result.begin(), result.end()); |
| std::reverse(result.begin(), result.end()); |
| return result; |
| } |
| |
| static std::string get_ce_key_current_path(const std::string& directory_path) { |
| return directory_path + "/current"; |
| } |
| |
| static bool get_ce_key_new_path(const std::string& directory_path, |
| const std::vector<std::string>& paths, std::string* ce_key_path) { |
| if (paths.empty()) { |
| *ce_key_path = get_ce_key_current_path(directory_path); |
| return true; |
| } |
| for (unsigned int i = 0; i < UINT_MAX; i++) { |
| auto const candidate = StringPrintf("%s/cx%010u", directory_path.c_str(), i); |
| if (paths[0] < candidate) { |
| *ce_key_path = candidate; |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| // Discard all keys but the named one; rename it to canonical name. |
| // No point in acting on errors in this; ignore them. |
| static void fixate_user_ce_key(const std::string& directory_path, const std::string& to_fix, |
| const std::vector<std::string>& paths) { |
| for (auto const other_path : paths) { |
| if (other_path != to_fix) { |
| ::destroyKey(other_path); |
| } |
| } |
| auto const current_path = get_ce_key_current_path(directory_path); |
| if (to_fix != current_path) { |
| LOG(INFO) << "Renaming " << to_fix << " to " << current_path; |
| if (rename(to_fix.c_str(), current_path.c_str()) != 0) { |
| PLOG(WARNING) << "Unable to rename " << to_fix << " to " << current_path; |
| return; |
| } |
| } |
| ::FsyncDirectory(directory_path); |
| } |
| |
| static bool read_and_fixate_user_ce_key(userid_t user_id, |
| const ::KeyAuthentication& auth, |
| KeyBuffer* ce_key) { |
| auto const directory_path = get_ce_key_directory_path(user_id); |
| auto const paths = get_ce_key_paths(directory_path); |
| for (auto const ce_key_path : paths) { |
| LOG(INFO) << "Trying user CE key " << ce_key_path; |
| if (retrieveKey(ce_key_path, auth, ce_key, true)) { |
| LOG(INFO) << "Successfully retrieved key"; |
| fixate_user_ce_key(directory_path, ce_key_path, paths); |
| return true; |
| } |
| } |
| LOG(ERROR) << "Failed to find working ce key for user " << user_id; |
| return false; |
| } |
| |
| static bool IsEmmcStorage(const std::string& blk_device) { |
| // Handle symlinks. |
| std::string real_path; |
| if (!Realpath(blk_device, &real_path)) { |
| real_path = blk_device; |
| } |
| |
| // Handle logical volumes. |
| auto& dm = DeviceMapper::Instance(); |
| for (;;) { |
| auto parent = dm.GetParentBlockDeviceByPath(real_path); |
| if (!parent.has_value()) break; |
| real_path = *parent; |
| } |
| |
| // Now we should have the "real" block device. |
| LOG(INFO) << "IsEmmcStorage(): blk_device = " << blk_device << ", real_path=" << real_path; |
| return StartsWith(Basename(real_path), "mmcblk"); |
| } |
| |
| // Retrieve the options to use for encryption policies on the /data filesystem. |
| static bool get_data_file_encryption_options(EncryptionOptions* options) { |
| if (!ReadDefaultFstab(&fstab_default)) { |
| PLOG(ERROR) << "Failed to open default fstab"; |
| return false; |
| } |
| auto entry = GetEntryForMountPoint(&fstab_default, DATA_MNT_POINT); |
| if (entry == nullptr) { |
| LOG(ERROR) << "No mount point entry for " << DATA_MNT_POINT; |
| return false; |
| } |
| if (!ParseOptions(entry->encryption_options, options)) { |
| LOG(ERROR) << "Unable to parse encryption options for " << DATA_MNT_POINT ": " |
| << entry->encryption_options; |
| return false; |
| } |
| if (options->version == 1) { |
| options->use_hw_wrapped_key = |
| GetEntryForMountPoint(&fstab_default, DATA_MNT_POINT)->fs_mgr_flags.wrapped_key; |
| } |
| if ((options->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32) && |
| !IsEmmcStorage(entry->blk_device)) { |
| LOG(ERROR) << "The emmc_optimized encryption flag is only allowed on eMMC storage. Remove " |
| "this flag from the device's fstab"; |
| return false; |
| } |
| return true; |
| } |
| |
| static bool install_storage_key(const std::string& mountpoint, const EncryptionOptions& options, |
| const KeyBuffer& key, EncryptionPolicy* policy) { |
| KeyBuffer ephemeral_wrapped_key; |
| if (options.use_hw_wrapped_key) { |
| if (!exportWrappedStorageKey(key, &ephemeral_wrapped_key)) { |
| LOG(ERROR) << "Failed to get ephemeral wrapped key"; |
| return false; |
| } |
| } |
| return installKey(mountpoint, options, options.use_hw_wrapped_key ? ephemeral_wrapped_key : key, |
| policy); |
| } |
| |
| // Retrieve the options to use for encryption policies on adoptable storage. |
| static bool get_volume_file_encryption_options(EncryptionOptions* options) { |
| // If we give the empty string, libfscrypt will use the default (currently XTS) |
| auto contents_mode = android::base::GetProperty("ro.crypto.volume.contents_mode", ""); |
| // HEH as default was always a mistake. Use the libfscrypt default (CTS) |
| // for devices launching on versions above Android 10. |
| auto first_api_level = GetFirstApiLevel(); |
| constexpr uint64_t pre_gki_level = 29; |
| auto filenames_mode = |
| android::base::GetProperty("ro.crypto.volume.filenames_mode", |
| first_api_level > pre_gki_level ? "" : "aes-256-heh"); |
| auto options_string = android::base::GetProperty("ro.crypto.volume.options", |
| contents_mode + ":" + filenames_mode); |
| if (!ParseOptionsForApiLevel(first_api_level, options_string, options)) { |
| LOG(ERROR) << "Unable to parse volume encryption options: " << options_string; |
| return false; |
| } |
| if (options->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32) { |
| LOG(ERROR) << "The emmc_optimized encryption flag is only allowed on eMMC storage. Remove " |
| "this flag from ro.crypto.volume.options"; |
| return false; |
| } |
| return true; |
| } |
| |
| bool is_metadata_wrapped_key_supported() { |
| if (!ReadDefaultFstab(&fstab_default)) { |
| PLOG(ERROR) << "Failed to open default fstab"; |
| return false; |
| } |
| return GetEntryForMountPoint(&fstab_default, METADATA_MNT_POINT)->fs_mgr_flags.wrapped_key; |
| } |
| |
| static bool read_and_install_user_ce_key(userid_t user_id, |
| const ::KeyAuthentication& auth) { |
| if (s_ce_policies.count(user_id) != 0) return true; |
| EncryptionOptions options; |
| if (!get_data_file_encryption_options(&options)) return false; |
| KeyBuffer ce_key; |
| if (!read_and_fixate_user_ce_key(user_id, auth, &ce_key)) return false; |
| EncryptionPolicy ce_policy; |
| if (!install_storage_key(DATA_MNT_POINT, options, ce_key, &ce_policy)) return false; |
| s_ce_policies[user_id] = ce_policy; |
| LOG(INFO) << "Installed ce key for user " << user_id; |
| return true; |
| } |
| |
| static bool prepare_dir(const std::string& dir, mode_t mode, uid_t uid, gid_t gid) { |
| LOG(INFO) << "Preparing: " << dir; |
| if (fs_prepare_dir(dir.c_str(), mode, uid, gid) != 0) { |
| PLOG(ERROR) << "Failed to prepare " << dir; |
| return false; |
| } |
| return true; |
| } |
| |
| static bool destroy_dir(const std::string& dir) { |
| LOG(INFO) << "Destroying: " << dir; |
| if (rmdir(dir.c_str()) != 0 && errno != ENOENT) { |
| PLOG(ERROR) << "Failed to destroy " << dir; |
| return false; |
| } |
| return true; |
| } |
| |
| // NB this assumes that there is only one thread listening for crypt commands, because |
| // it creates keys in a fixed location. |
| static bool create_and_install_user_keys(userid_t user_id, bool create_ephemeral) { |
| LOG(INFO) << "fscrypt::create_and_install_user_keys"; |
| EncryptionOptions options; |
| if (!get_data_file_encryption_options(&options)) return false; |
| KeyBuffer de_key, ce_key; |
| if (!generateStorageKey(makeGen(options), &de_key)) return false; |
| if (!generateStorageKey(makeGen(options), &ce_key)) return false; |
| if (create_ephemeral) { |
| // If the key should be created as ephemeral, don't store it. |
| s_ephemeral_users.insert(user_id); |
| } else { |
| auto const directory_path = get_ce_key_directory_path(user_id); |
| if (!prepare_dir(directory_path, 0700, AID_ROOT, AID_ROOT)) return false; |
| auto const paths = get_ce_key_paths(directory_path); |
| std::string ce_key_path; |
| if (!get_ce_key_new_path(directory_path, paths, &ce_key_path)) return false; |
| if (!::storeKeyAtomically(ce_key_path, user_key_temp, kEmptyAuthentication, |
| ce_key)) |
| return false; |
| fixate_user_ce_key(directory_path, ce_key_path, paths); |
| // Write DE key second; once this is written, all is good. |
| if (!::storeKeyAtomically(get_de_key_path(user_id), user_key_temp, |
| kEmptyAuthentication, de_key)) |
| return false; |
| } |
| EncryptionPolicy de_policy; |
| if (!install_storage_key(DATA_MNT_POINT, options, de_key, &de_policy)) return false; |
| s_de_policies[user_id] = de_policy; |
| LOG(INFO) << "fscrypt::added de_policy"; |
| EncryptionPolicy ce_policy; |
| if (!install_storage_key(DATA_MNT_POINT, options, ce_key, &ce_policy)) return false; |
| s_ce_policies[user_id] = ce_policy; |
| LOG(INFO) << "Created keys for user " << user_id; |
| return true; |
| } |
| |
| bool lookup_policy(const std::map<userid_t, EncryptionPolicy>& key_map, userid_t user_id, |
| EncryptionPolicy* policy) { |
| auto refi = key_map.find(user_id); |
| if (refi == key_map.end()) { |
| LOG(ERROR) << "Cannot find key for " << user_id; |
| return false; |
| } |
| *policy = refi->second; |
| return true; |
| } |
| |
| static bool is_numeric(const char* name) { |
| for (const char* p = name; *p != '\0'; p++) { |
| if (!isdigit(*p)) return false; |
| } |
| return true; |
| } |
| |
| static bool load_all_de_keys() { |
| LOG(INFO) << "fscrypt::load_all_de_keys"; |
| EncryptionOptions options; |
| if (!get_data_file_encryption_options(&options)) return false; |
| auto de_dir = user_key_dir + "/de"; |
| auto dirp = std::unique_ptr<DIR, int (*)(DIR*)>(opendir(de_dir.c_str()), closedir); |
| if (!dirp) { |
| PLOG(ERROR) << "Unable to read de key directory"; |
| return false; |
| } |
| for (;;) { |
| errno = 0; |
| auto entry = readdir(dirp.get()); |
| if (!entry) { |
| if (errno) { |
| PLOG(ERROR) << "Unable to read de key directory"; |
| return false; |
| } |
| break; |
| } |
| if (entry->d_type != DT_DIR || !is_numeric(entry->d_name)) { |
| LOG(INFO) << "Skipping non-de-key " << entry->d_name; |
| continue; |
| } |
| userid_t user_id = std::stoi(entry->d_name); |
| auto key_path = de_dir + "/" + entry->d_name; |
| KeyBuffer de_key; |
| if (!retrieveKey(key_path, kEmptyAuthentication, &de_key, true)) return false; |
| EncryptionPolicy de_policy; |
| if (!install_storage_key(DATA_MNT_POINT, options, de_key, &de_policy)) return false; |
| auto ret = s_de_policies.insert({user_id, de_policy}); |
| LOG(INFO) << "fscrypt::load_all_de_keys::s_de_policies::size::" << s_de_policies.size(); |
| if (!ret.second && ret.first->second != de_policy) { |
| LOG(INFO) << "DE policy for user" << user_id << " changed"; |
| return false; |
| } |
| LOG(INFO) << "Installed de key for user " << user_id; |
| std::string user_prop = "twrp.user." + std::to_string(user_id) + ".decrypt"; |
| property_set(user_prop.c_str(), "0"); |
| } |
| // fscrypt:TODO: go through all DE directories, ensure that all user dirs have the |
| // correct policy set on them, and that no rogue ones exist. |
| return true; |
| } |
| |
| // Attempt to reinstall CE keys for users that we think are unlocked. |
| static bool try_reload_ce_keys() { |
| for (const auto& it : s_ce_policies) { |
| if (!::reloadKeyFromSessionKeyring(DATA_MNT_POINT, it.second)) { |
| LOG(ERROR) << "Failed to load CE key from session keyring for user " << it.first; |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| bool fscrypt_initialize_systemwide_keys() { |
| LOG(INFO) << "fscrypt_initialize_systemwide_keys"; |
| |
| EncryptionOptions options; |
| if (!get_data_file_encryption_options(&options)) return false; |
| |
| KeyBuffer device_key; |
| if (!retrieveOrGenerateKey(device_key_path, device_key_temp, kEmptyAuthentication, |
| makeGen(options), &device_key)) |
| return false; |
| |
| EncryptionPolicy device_policy; |
| if (!install_storage_key(DATA_MNT_POINT, options, device_key, &device_policy)) return false; |
| |
| std::string options_string; |
| if (!OptionsToString(device_policy.options, &options_string)) { |
| LOG(ERROR) << "Unable to serialize options"; |
| return false; |
| } |
| std::string options_filename = std::string(DATA_MNT_POINT) + fscrypt_key_mode; |
| if (!::writeStringToFile(options_string, options_filename)) return false; |
| |
| std::string ref_filename = std::string(DATA_MNT_POINT) + fscrypt_key_ref; |
| de_key_raw_ref = device_policy.key_raw_ref; |
| if (!::writeStringToFile(device_policy.key_raw_ref, ref_filename)) return false; |
| LOG(INFO) << "Wrote system DE key reference to:" << ref_filename; |
| |
| KeyBuffer per_boot_key; |
| if (!generateStorageKey(makeGen(options), &per_boot_key)) return false; |
| EncryptionPolicy per_boot_policy; |
| if (!install_storage_key(DATA_MNT_POINT, options, per_boot_key, &per_boot_policy)) return false; |
| std::string per_boot_ref_filename = std::string("/data") + fscrypt_key_per_boot_ref; |
| if (!::writeStringToFile(per_boot_policy.key_raw_ref, per_boot_ref_filename)) |
| return false; |
| LOG(INFO) << "Wrote per boot key reference to:" << per_boot_ref_filename; |
| |
| if (!::FsyncDirectory(device_key_dir)) return false; |
| return true; |
| } |
| |
| bool fscrypt_init_user0() { |
| if (!ReadDefaultFstab(&fstab_default)) { |
| PLOG(ERROR) << "Failed to open default fstab"; |
| return -1; |
| } |
| LOG(INFO) << "fscrypt_init_user0"; |
| if (fscrypt_is_native()) { |
| if (!prepare_dir(user_key_dir, 0700, AID_ROOT, AID_ROOT)) return false; |
| if (!prepare_dir(user_key_dir + "/ce", 0700, AID_ROOT, AID_ROOT)) return false; |
| if (!prepare_dir(user_key_dir + "/de", 0700, AID_ROOT, AID_ROOT)) return false; |
| if (!::pathExists(get_de_key_path(0))) { |
| if (!create_and_install_user_keys(0, false)) return false; |
| } |
| // TODO: switch to loading only DE_0 here once framework makes |
| // explicit calls to install DE keys for secondary users |
| if (!load_all_de_keys()) return false; |
| } |
| // We can only safely prepare DE storage here, since CE keys are probably |
| // entangled with user credentials. The framework will always prepare CE |
| // storage once CE keys are installed. |
| LOG(INFO) << "attempting fscrypt_prepare_user_storage"; |
| if (!fscrypt_prepare_user_storage("", 0, 0, android::os::IVold::STORAGE_FLAG_DE)) { |
| LOG(ERROR) << "Failed to prepare user 0 storage"; |
| return false; |
| } |
| |
| // If this is a non-FBE device that recently left an emulated mode, |
| // restore user data directories to known-good state. |
| if (!fscrypt_is_native() && !fscrypt_is_emulated()) { |
| LOG(INFO) << "unlocking data media"; |
| fscrypt_unlock_user_key(0, 0, "!", "!"); |
| } |
| |
| // In some scenarios (e.g. userspace reboot) we might unmount userdata |
| // without doing a hard reboot. If CE keys were stored in fs keyring then |
| // they will be lost after unmount. Attempt to re-install them. |
| if (fscrypt_is_native() && ::isFsKeyringSupported()) { |
| LOG(INFO) << "reloading ce keys"; |
| if (!try_reload_ce_keys()) return false; |
| } |
| |
| return true; |
| } |
| |
| bool fscrypt_vold_create_user_key(userid_t user_id, int serial, bool ephemeral) { |
| LOG(INFO) << "fscrypt_vold_create_user_key for " << user_id << " serial " << serial; |
| if (!fscrypt_is_native()) { |
| return true; |
| } |
| // FIXME test for existence of key that is not loaded yet |
| if (s_ce_policies.count(user_id) != 0) { |
| LOG(ERROR) << "Already exists, can't fscrypt_vold_create_user_key for " << user_id |
| << " serial " << serial; |
| // FIXME should we fail the command? |
| return true; |
| } |
| if (!create_and_install_user_keys(user_id, ephemeral)) { |
| return false; |
| } |
| return true; |
| } |
| |
| // "Lock" all encrypted directories whose key has been removed. This is needed |
| // in the case where the keys are being put in the session keyring (rather in |
| // the newer filesystem-level keyrings), because removing a key from the session |
| // keyring doesn't affect inodes in the kernel's inode cache whose per-file key |
| // was already set up. So to remove the per-file keys and make the files |
| // "appear encrypted", these inodes must be evicted. |
| // |
| // To do this, sync() to clean all dirty inodes, then drop all reclaimable slab |
| // objects systemwide. This is overkill, but it's the best available method |
| // currently. Don't use drop_caches mode "3" because that also evicts pagecache |
| // for in-use files; all files relevant here are already closed and sync'ed. |
| static void drop_caches_if_needed() { |
| if (::isFsKeyringSupported()) { |
| return; |
| } |
| sync(); |
| if (!writeStringToFile("2", "/proc/sys/vm/drop_caches")) { |
| PLOG(ERROR) << "Failed to drop caches during key eviction"; |
| } |
| } |
| |
| static bool evict_ce_key(userid_t user_id) { |
| bool success = true; |
| EncryptionPolicy policy; |
| // If we haven't loaded the CE key, no need to evict it. |
| if (lookup_policy(s_ce_policies, user_id, &policy)) { |
| success &= ::evictKey(DATA_MNT_POINT, policy); |
| drop_caches_if_needed(); |
| } |
| s_ce_policies.erase(user_id); |
| return success; |
| } |
| |
| bool fscrypt_destroy_user_key(userid_t user_id) { |
| LOG(INFO) << "fscrypt_destroy_user_key(" << user_id << ")"; |
| if (!fscrypt_is_native()) { |
| return true; |
| } |
| bool success = true; |
| success &= evict_ce_key(user_id); |
| EncryptionPolicy de_policy; |
| success &= lookup_policy(s_de_policies, user_id, &de_policy) && |
| ::evictKey(DATA_MNT_POINT, de_policy); |
| s_de_policies.erase(user_id); |
| auto it = s_ephemeral_users.find(user_id); |
| if (it != s_ephemeral_users.end()) { |
| s_ephemeral_users.erase(it); |
| } else { |
| for (auto const path : get_ce_key_paths(get_ce_key_directory_path(user_id))) { |
| success &= ::destroyKey(path); |
| } |
| auto de_key_path = get_de_key_path(user_id); |
| if (::pathExists(de_key_path)) { |
| success &= ::destroyKey(de_key_path); |
| } else { |
| LOG(INFO) << "Not present so not erasing: " << de_key_path; |
| } |
| } |
| return success; |
| } |
| |
| static bool emulated_lock(const std::string& path) { |
| if (chmod(path.c_str(), 0000) != 0) { |
| PLOG(ERROR) << "Failed to chmod " << path; |
| return false; |
| } |
| #if EMULATED_USES_SELINUX |
| if (setfilecon(path.c_str(), "u:object_r:storage_stub_file:s0") != 0) { |
| PLOG(WARNING) << "Failed to setfilecon " << path; |
| return false; |
| } |
| #endif |
| return true; |
| } |
| |
| static bool emulated_unlock(const std::string& path, mode_t mode) { |
| if (chmod(path.c_str(), mode) != 0) { |
| PLOG(ERROR) << "Failed to chmod " << path; |
| // FIXME temporary workaround for b/26713622 |
| if (fscrypt_is_emulated()) return false; |
| } |
| #if EMULATED_USES_SELINUX |
| if (selinux_android_restorecon(path.c_str(), SELINUX_ANDROID_RESTORECON_FORCE) != 0) { |
| PLOG(WARNING) << "Failed to restorecon " << path; |
| // FIXME temporary workaround for b/26713622 |
| if (fscrypt_is_emulated()) return false; |
| } |
| #endif |
| return true; |
| } |
| |
| static bool parse_hex(const std::string& hex, std::string* result) { |
| if (hex == "!") { |
| *result = ""; |
| return true; |
| } |
| if (::HexToStr(hex, *result) != 0) { |
| LOG(ERROR) << "Invalid FBE hex string"; // Don't log the string for security reasons |
| return false; |
| } |
| return true; |
| } |
| |
| static std::optional<::KeyAuthentication> authentication_from_hex( |
| const std::string& token_hex, const std::string& secret_hex) { |
| std::string token, secret; |
| if (!parse_hex(token_hex, &token)) return std::optional<::KeyAuthentication>(); |
| if (!parse_hex(secret_hex, &secret)) return std::optional<::KeyAuthentication>(); |
| if (secret.empty()) { |
| return kEmptyAuthentication; |
| } else { |
| return ::KeyAuthentication(token, secret); |
| } |
| } |
| |
| static std::string volkey_path(const std::string& misc_path, const std::string& volume_uuid) { |
| return misc_path + "/vold/volume_keys/" + volume_uuid + "/default"; |
| } |
| |
| static std::string volume_secdiscardable_path(const std::string& volume_uuid) { |
| return systemwide_volume_key_dir + "/" + volume_uuid + "/secdiscardable"; |
| } |
| |
| static bool read_or_create_volkey(const std::string& misc_path, const std::string& volume_uuid, |
| EncryptionPolicy* policy) { |
| auto secdiscardable_path = volume_secdiscardable_path(volume_uuid); |
| std::string secdiscardable_hash; |
| if (::pathExists(secdiscardable_path)) { |
| if (!readSecdiscardable(secdiscardable_path, &secdiscardable_hash)) |
| return false; |
| } else { |
| if (fs_mkdirs(secdiscardable_path.c_str(), 0700) != 0) { |
| PLOG(ERROR) << "Creating directories for: " << secdiscardable_path; |
| return false; |
| } |
| if (!::createSecdiscardable(secdiscardable_path, &secdiscardable_hash)) |
| return false; |
| } |
| auto key_path = volkey_path(misc_path, volume_uuid); |
| if (fs_mkdirs(key_path.c_str(), 0700) != 0) { |
| PLOG(ERROR) << "Creating directories for: " << key_path; |
| return false; |
| } |
| ::KeyAuthentication auth("", secdiscardable_hash); |
| |
| EncryptionOptions options; |
| if (!get_volume_file_encryption_options(&options)) return false; |
| KeyBuffer key; |
| if (!retrieveOrGenerateKey(key_path, key_path + "_tmp", auth, makeGen(options), &key)) |
| return false; |
| if (!install_storage_key(BuildDataPath(volume_uuid), options, key, policy)) return false; |
| return true; |
| } |
| |
| static bool destroy_volkey(const std::string& misc_path, const std::string& volume_uuid) { |
| auto path = volkey_path(misc_path, volume_uuid); |
| if (!::pathExists(path)) return true; |
| return ::destroyKey(path); |
| } |
| |
| static bool fscrypt_rewrap_user_key(userid_t user_id, int serial, |
| const ::KeyAuthentication& retrieve_auth, |
| const ::KeyAuthentication& store_auth) { |
| if (s_ephemeral_users.count(user_id) != 0) return true; |
| auto const directory_path = get_ce_key_directory_path(user_id); |
| KeyBuffer ce_key; |
| std::string ce_key_current_path = get_ce_key_current_path(directory_path); |
| if (retrieveKey(ce_key_current_path, retrieve_auth, &ce_key, true)) { |
| LOG(INFO) << "Successfully retrieved key"; |
| // TODO(147732812): Remove this once Locksettingservice is fixed. |
| // Currently it calls fscrypt_clear_user_key_auth with a secret when lockscreen is |
| // changed from swipe to none or vice-versa |
| } else if (retrieveKey(ce_key_current_path, kEmptyAuthentication, &ce_key, true)) { |
| LOG(INFO) << "Successfully retrieved key with empty auth"; |
| } else { |
| LOG(ERROR) << "Failed to retrieve key for user " << user_id; |
| return false; |
| } |
| auto const paths = get_ce_key_paths(directory_path); |
| std::string ce_key_path; |
| if (!get_ce_key_new_path(directory_path, paths, &ce_key_path)) return false; |
| if (!::storeKeyAtomically(ce_key_path, user_key_temp, store_auth, ce_key)) |
| return false; |
| if (!::FsyncDirectory(directory_path)) return false; |
| return true; |
| } |
| |
| bool fscrypt_add_user_key_auth(userid_t user_id, int serial, const std::string& token_hex, |
| const std::string& secret_hex) { |
| LOG(INFO) << "fscrypt_add_user_key_auth " << user_id << " serial=" << serial |
| << " token_present=" << (token_hex != "!"); |
| if (!fscrypt_is_native()) return true; |
| auto auth = authentication_from_hex(token_hex, secret_hex); |
| if (!auth) return false; |
| return fscrypt_rewrap_user_key(user_id, serial, kEmptyAuthentication, *auth); |
| } |
| |
| bool fscrypt_clear_user_key_auth(userid_t user_id, int serial, const std::string& token_hex, |
| const std::string& secret_hex) { |
| LOG(INFO) << "fscrypt_clear_user_key_auth " << user_id << " serial=" << serial |
| << " token_present=" << (token_hex != "!"); |
| if (!fscrypt_is_native()) return true; |
| auto auth = authentication_from_hex(token_hex, secret_hex); |
| if (!auth) return false; |
| return fscrypt_rewrap_user_key(user_id, serial, *auth, kEmptyAuthentication); |
| } |
| |
| bool fscrypt_fixate_newest_user_key_auth(userid_t user_id) { |
| LOG(INFO) << "fscrypt_fixate_newest_user_key_auth " << user_id; |
| if (!fscrypt_is_native()) return true; |
| if (s_ephemeral_users.count(user_id) != 0) return true; |
| auto const directory_path = get_ce_key_directory_path(user_id); |
| auto const paths = get_ce_key_paths(directory_path); |
| if (paths.empty()) { |
| LOG(ERROR) << "No ce keys present, cannot fixate for user " << user_id; |
| return false; |
| } |
| fixate_user_ce_key(directory_path, paths[0], paths); |
| return true; |
| } |
| |
| // TODO: rename to 'install' for consistency, and take flags to know which keys to install |
| bool fscrypt_unlock_user_key(userid_t user_id, int serial, const std::string& token_hex, |
| const std::string& secret_hex) { |
| LOG(INFO) << "fscrypt_unlock_user_key " << user_id << " serial=" << serial |
| << " token_present=" << (token_hex != "!"); |
| if (fscrypt_is_native()) { |
| if (s_ce_policies.count(user_id) != 0) { |
| LOG(WARNING) << "Tried to unlock already-unlocked key for user " << user_id; |
| return true; |
| } |
| auto auth = authentication_from_hex(token_hex, secret_hex); |
| if (!auth) return false; |
| if (!read_and_install_user_ce_key(user_id, *auth)) { |
| LOG(ERROR) << "Couldn't read key for " << user_id; |
| return false; |
| } |
| } else { |
| // When in emulation mode, we just use chmod. However, we also |
| // unlock directories when not in emulation mode, to bring devices |
| // back into a known-good state. |
| if (!emulated_unlock(::BuildDataSystemCePath(user_id), 0771) || |
| !emulated_unlock(::BuildDataMiscCePath(user_id), 01771) || |
| !emulated_unlock(::BuildDataMediaCePath("", user_id), 0770) || |
| !emulated_unlock(::BuildDataUserCePath("", user_id), 0771)) { |
| LOG(ERROR) << "Failed to unlock user " << user_id; |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| // TODO: rename to 'evict' for consistency |
| bool fscrypt_lock_user_key(userid_t user_id) { |
| LOG(INFO) << "fscrypt_lock_user_key " << user_id; |
| if (fscrypt_is_native()) { |
| return evict_ce_key(user_id); |
| } else if (fscrypt_is_emulated()) { |
| // When in emulation mode, we just use chmod |
| if (!emulated_lock(::BuildDataSystemCePath(user_id)) || |
| !emulated_lock(::BuildDataMiscCePath(user_id)) || |
| !emulated_lock(::BuildDataMediaCePath("", user_id)) || |
| !emulated_lock(::BuildDataUserCePath("", user_id))) { |
| LOG(ERROR) << "Failed to lock user " << user_id; |
| return false; |
| } |
| } |
| |
| return true; |
| } |
| |
| static bool prepare_subdirs(const std::string& action, const std::string& volume_uuid, |
| userid_t user_id, int flags) { |
| if (0 != ::ForkExecvp( |
| std::vector<std::string>{prepare_subdirs_path, action, volume_uuid, |
| std::to_string(user_id), std::to_string(flags)})) { |
| LOG(ERROR) << "vold_prepare_subdirs failed"; |
| return false; |
| } |
| return true; |
| } |
| |
| bool fscrypt_prepare_user_storage(const std::string& volume_uuid, userid_t user_id, int serial, |
| int flags) { |
| LOG(INFO) << "fscrypt_prepare_user_storage for volume " << escape_empty(volume_uuid) |
| << ", user " << user_id << ", serial " << serial << ", flags " << flags; |
| |
| if (flags & android::os::IVold::STORAGE_FLAG_DE) { |
| // DE_sys key |
| auto system_legacy_path = ::BuildDataSystemLegacyPath(user_id); |
| auto misc_legacy_path = ::BuildDataMiscLegacyPath(user_id); |
| auto profiles_de_path = ::BuildDataProfilesDePath(user_id); |
| |
| // DE_n key |
| auto system_de_path = ::BuildDataSystemDePath(user_id); |
| auto misc_de_path = ::BuildDataMiscDePath(user_id); |
| auto vendor_de_path = ::BuildDataVendorDePath(user_id); |
| auto user_de_path = ::BuildDataUserDePath(volume_uuid, user_id); |
| |
| if (volume_uuid.empty()) { |
| if (!prepare_dir(system_legacy_path, 0700, AID_SYSTEM, AID_SYSTEM)) return false; |
| #if MANAGE_MISC_DIRS |
| if (!prepare_dir(misc_legacy_path, 0750, multiuser_get_uid(user_id, AID_SYSTEM), |
| multiuser_get_uid(user_id, AID_EVERYBODY))) |
| return false; |
| #endif |
| if (!prepare_dir(profiles_de_path, 0771, AID_SYSTEM, AID_SYSTEM)) return false; |
| |
| if (!prepare_dir(system_de_path, 0770, AID_SYSTEM, AID_SYSTEM)) return false; |
| if (!prepare_dir(misc_de_path, 01771, AID_SYSTEM, AID_MISC)) return false; |
| if (!prepare_dir(vendor_de_path, 0771, AID_ROOT, AID_ROOT)) return false; |
| } |
| if (!prepare_dir(user_de_path, 0771, AID_SYSTEM, AID_SYSTEM)) return false; |
| if (fscrypt_is_native()) { |
| EncryptionPolicy de_policy; |
| if (volume_uuid.empty()) { |
| if (!lookup_policy(s_de_policies, user_id, &de_policy)) return false; |
| if (!EnsurePolicy(de_policy, system_de_path)) return false; |
| if (!EnsurePolicy(de_policy, misc_de_path)) return false; |
| if (!EnsurePolicy(de_policy, vendor_de_path)) return false; |
| } else { |
| if (!read_or_create_volkey(misc_de_path, volume_uuid, &de_policy)) return false; |
| } |
| if (!EnsurePolicy(de_policy, user_de_path)) return false; |
| } |
| } |
| |
| if (flags & android::os::IVold::STORAGE_FLAG_CE) { |
| // CE_n key |
| auto system_ce_path = ::BuildDataSystemCePath(user_id); |
| auto misc_ce_path = ::BuildDataMiscCePath(user_id); |
| auto vendor_ce_path = ::BuildDataVendorCePath(user_id); |
| auto media_ce_path = ::BuildDataMediaCePath(volume_uuid, user_id); |
| auto user_ce_path = ::BuildDataUserCePath(volume_uuid, user_id); |
| |
| if (volume_uuid.empty()) { |
| if (!prepare_dir(system_ce_path, 0770, AID_SYSTEM, AID_SYSTEM)) return false; |
| if (!prepare_dir(misc_ce_path, 01771, AID_SYSTEM, AID_MISC)) return false; |
| if (!prepare_dir(vendor_ce_path, 0771, AID_ROOT, AID_ROOT)) return false; |
| } |
| if (!prepare_dir(media_ce_path, 0770, AID_MEDIA_RW, AID_MEDIA_RW)) return false; |
| |
| if (!prepare_dir(user_ce_path, 0771, AID_SYSTEM, AID_SYSTEM)) return false; |
| |
| if (fscrypt_is_native()) { |
| EncryptionPolicy ce_policy; |
| if (volume_uuid.empty()) { |
| if (!lookup_policy(s_ce_policies, user_id, &ce_policy)) return false; |
| if (!EnsurePolicy(ce_policy, system_ce_path)) return false; |
| if (!EnsurePolicy(ce_policy, misc_ce_path)) return false; |
| if (!EnsurePolicy(ce_policy, vendor_ce_path)) return false; |
| } else { |
| if (!read_or_create_volkey(misc_ce_path, volume_uuid, &ce_policy)) return false; |
| } |
| if (!EnsurePolicy(ce_policy, media_ce_path)) return false; |
| if (!EnsurePolicy(ce_policy, user_ce_path)) return false; |
| } |
| |
| if (volume_uuid.empty()) { |
| // Now that credentials have been installed, we can run restorecon |
| // over these paths |
| // NOTE: these paths need to be kept in sync with libselinux |
| ::RestoreconRecursive(system_ce_path); |
| ::RestoreconRecursive(vendor_ce_path); |
| ::RestoreconRecursive(misc_ce_path); |
| } |
| } |
| if (!prepare_subdirs("prepare", volume_uuid, user_id, flags)) return false; |
| |
| return true; |
| } |
| |
| bool fscrypt_destroy_user_storage(const std::string& volume_uuid, userid_t user_id, int flags) { |
| LOG(INFO) << "fscrypt_destroy_user_storage for volume " << escape_empty(volume_uuid) |
| << ", user " << user_id << ", flags " << flags; |
| bool res = true; |
| |
| res &= prepare_subdirs("destroy", volume_uuid, user_id, flags); |
| |
| if (flags & android::os::IVold::STORAGE_FLAG_CE) { |
| // CE_n key |
| auto system_ce_path = ::BuildDataSystemCePath(user_id); |
| auto misc_ce_path = ::BuildDataMiscCePath(user_id); |
| auto vendor_ce_path = ::BuildDataVendorCePath(user_id); |
| auto media_ce_path = ::BuildDataMediaCePath(volume_uuid, user_id); |
| auto user_ce_path = ::BuildDataUserCePath(volume_uuid, user_id); |
| |
| res &= destroy_dir(media_ce_path); |
| res &= destroy_dir(user_ce_path); |
| if (volume_uuid.empty()) { |
| res &= destroy_dir(system_ce_path); |
| res &= destroy_dir(misc_ce_path); |
| res &= destroy_dir(vendor_ce_path); |
| } else { |
| if (fscrypt_is_native()) { |
| res &= destroy_volkey(misc_ce_path, volume_uuid); |
| } |
| } |
| } |
| |
| if (flags & android::os::IVold::STORAGE_FLAG_DE) { |
| // DE_sys key |
| auto system_legacy_path = ::BuildDataSystemLegacyPath(user_id); |
| auto misc_legacy_path = ::BuildDataMiscLegacyPath(user_id); |
| auto profiles_de_path = ::BuildDataProfilesDePath(user_id); |
| |
| // DE_n key |
| auto system_de_path = ::BuildDataSystemDePath(user_id); |
| auto misc_de_path = ::BuildDataMiscDePath(user_id); |
| auto vendor_de_path = ::BuildDataVendorDePath(user_id); |
| auto user_de_path = ::BuildDataUserDePath(volume_uuid, user_id); |
| |
| res &= destroy_dir(user_de_path); |
| if (volume_uuid.empty()) { |
| res &= destroy_dir(system_legacy_path); |
| #if MANAGE_MISC_DIRS |
| res &= destroy_dir(misc_legacy_path); |
| #endif |
| res &= destroy_dir(profiles_de_path); |
| res &= destroy_dir(system_de_path); |
| res &= destroy_dir(misc_de_path); |
| res &= destroy_dir(vendor_de_path); |
| } else { |
| if (fscrypt_is_native()) { |
| res &= destroy_volkey(misc_de_path, volume_uuid); |
| } |
| } |
| } |
| |
| return res; |
| } |
| |
| static bool destroy_volume_keys(const std::string& directory_path, const std::string& volume_uuid) { |
| auto dirp = std::unique_ptr<DIR, int (*)(DIR*)>(opendir(directory_path.c_str()), closedir); |
| if (!dirp) { |
| PLOG(ERROR) << "Unable to open directory: " + directory_path; |
| return false; |
| } |
| bool res = true; |
| for (;;) { |
| errno = 0; |
| auto const entry = readdir(dirp.get()); |
| if (!entry) { |
| if (errno) { |
| PLOG(ERROR) << "Unable to read directory: " + directory_path; |
| return false; |
| } |
| break; |
| } |
| if (entry->d_type != DT_DIR || entry->d_name[0] == '.') { |
| LOG(INFO) << "Skipping non-user " << entry->d_name; |
| continue; |
| } |
| res &= destroy_volkey(directory_path + "/" + entry->d_name, volume_uuid); |
| } |
| return res; |
| } |
| |
| bool fscrypt_destroy_volume_keys(const std::string& volume_uuid) { |
| bool res = true; |
| LOG(INFO) << "fscrypt_destroy_volume_keys for volume " << escape_empty(volume_uuid); |
| auto secdiscardable_path = volume_secdiscardable_path(volume_uuid); |
| res &= ::runSecdiscardSingle(secdiscardable_path); |
| res &= destroy_volume_keys("/data/misc_ce", volume_uuid); |
| res &= destroy_volume_keys("/data/misc_de", volume_uuid); |
| return res; |
| } |
| |
| bool lookup_key_ref(const std::map<userid_t, android::fscrypt::EncryptionPolicy>& key_map, userid_t user_id, |
| std::string* raw_ref) { |
| auto refi = key_map.find(user_id); |
| if (refi == key_map.end()) { |
| LOG(ERROR) << "Cannot find key for " << user_id; |
| return false; |
| } |
| *raw_ref = refi->second.key_raw_ref; |
| return true; |
| } |