| /* |
| * 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 "Keymaster.h" |
| #include "KeyStorage.h" |
| #include "KeyUtil.h" |
| #include "Utils.h" |
| // #include "VoldUtil.h" |
| |
| #include <algorithm> |
| #include <map> |
| #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 "android/os/IVold.h" |
| |
| #include "cryptfs.h" |
| |
| #define EMULATED_USES_SELINUX 0 |
| #define MANAGE_MISC_DIRS 0 |
| |
| #include <cutils/fs.h> |
| #include <cutils/properties.h> |
| |
| #include <fscrypt/fscrypt.h> |
| #include <fs_mgr.h> |
| #include <keyutils.h> |
| |
| #include <android-base/file.h> |
| #include <android-base/logging.h> |
| #include <android-base/properties.h> |
| #include <android-base/stringprintf.h> |
| #include <android-base/unique_fd.h> |
| |
| |
| using android::base::StringPrintf; |
| using android::fs_mgr::GetEntryForMountPoint; |
| using android::vold::kEmptyAuthentication; |
| using android::vold::KeyBuffer; |
| using android::vold::Keymaster; |
| using android::hardware::keymaster::V4_0::KeyFormat; |
| // using android::vold::writeStringToFile; |
| |
| // Store main DE raw ref / policy |
| std::string de_raw_ref; |
| std::map<userid_t, std::string> s_de_key_raw_refs; |
| std::map<userid_t, std::string> s_ce_key_raw_refs; |
| |
| namespace { |
| |
| struct PolicyKeyRef { |
| std::string contents_mode; |
| std::string filenames_mode; |
| std::string key_raw_ref; |
| }; |
| |
| 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 = "/sbin/vold_prepare_subdirs"; |
| |
| const std::string systemwide_volume_key_dir = |
| std::string() + DATA_MNT_POINT + "/misc/vold/volume_keys"; |
| const int STORAGE_FLAG_DE = 1; |
| const int STORAGE_FLAG_CE = 2; |
| |
| bool s_systemwide_keys_initialized = false; |
| |
| android::fs_mgr::Fstab fstab_default; |
| |
| // Some users are ephemeral, don't try to wipe their keys from disk |
| std::set<userid_t> s_ephemeral_users; |
| |
| // TODO abolish this map, per b/26948053 |
| std::map<userid_t, KeyBuffer> s_ce_keys; |
| |
| } // namespace |
| |
| 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(DEBUG) << "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) { |
| android::vold::destroyKey(other_path); |
| } |
| } |
| auto const current_path = get_ce_key_current_path(directory_path); |
| if (to_fix != current_path) { |
| LOG(DEBUG) << "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; |
| } |
| } |
| android::vold::FsyncDirectory(directory_path); |
| } |
| |
| static bool read_and_fixate_user_ce_key(userid_t user_id, |
| const android::vold::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(DEBUG) << "Trying user CE key " << ce_key_path; |
| if (android::vold::retrieveKey(ce_key_path, auth, ce_key)) { |
| LOG(DEBUG) << "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 is_wrapped_key_supported_common(const std::string& mount_point) { |
| LOG(DEBUG) << "Determining wrapped-key support for " << mount_point; |
| std::string wrapped_key_supported = android::base::GetProperty("fbe.data.wrappedkey", "false"); |
| LOG(DEBUG) << "fbe.data.wrappedkey = " << wrapped_key_supported; |
| if (mount_point == DATA_MNT_POINT && wrapped_key_supported == "true") { |
| LOG(DEBUG) << "Wrapped key supported on " << mount_point; |
| return true; |
| } else { |
| return false; |
| } |
| } |
| |
| bool is_wrapped_key_supported() { |
| return is_wrapped_key_supported_common(DATA_MNT_POINT); |
| } |
| |
| bool is_wrapped_key_supported_external() { |
| return false; |
| } |
| |
| bool is_metadata_wrapped_key_supported_common(const std::string& mount_point) { |
| LOG(DEBUG) << "Determining metadata wrapped-key support for " << mount_point; |
| std::string wrapped_key_supported = android::base::GetProperty("fbe.metadata.wrappedkey", "false"); |
| LOG(DEBUG) << "fbe.metadata.wrappedkey = " << wrapped_key_supported; |
| if (mount_point == METADATA_MNT_POINT && wrapped_key_supported == "true") { |
| LOG(DEBUG) << "Wrapped key supported on " << mount_point; |
| return true; |
| } else { |
| return false; |
| } |
| } |
| |
| bool is_metadata_wrapped_key_supported() { |
| return is_metadata_wrapped_key_supported_common(METADATA_MNT_POINT); |
| } |
| |
| static bool read_and_install_user_ce_key(userid_t user_id, |
| const android::vold::KeyAuthentication& auth) { |
| if (s_ce_key_raw_refs.count(user_id) != 0) return true; |
| KeyBuffer ce_key; |
| if (!read_and_fixate_user_ce_key(user_id, auth, &ce_key)) return false; |
| std::string ce_raw_ref; |
| if (is_wrapped_key_supported()) { |
| KeyBuffer ephemeral_wrapped_key; |
| if (!getEphemeralWrappedKey(KeyFormat::RAW, ce_key, &ephemeral_wrapped_key)) { |
| LOG(ERROR) << "Failed to export ce key"; |
| return false; |
| } |
| ce_key = std::move(ephemeral_wrapped_key); |
| } |
| if (!android::vold::installKey(ce_key, &ce_raw_ref)) return false; |
| s_ce_keys[user_id] = std::move(ce_key); |
| s_ce_key_raw_refs[user_id] = ce_raw_ref; |
| LOG(DEBUG) << "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(DEBUG) << "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(DEBUG) << "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) { |
| KeyBuffer de_key, ce_key; |
| |
| if(is_wrapped_key_supported()) { |
| if (!generateWrappedKey(user_id, android::vold::KeyType::DE_USER, &de_key)) return false; |
| if (!generateWrappedKey(user_id, android::vold::KeyType::CE_USER, &ce_key)) return false; |
| } else { |
| if (!android::vold::randomKey(&de_key)) return false; |
| if (!android::vold::randomKey(&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 (!android::vold::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 (!android::vold::storeKeyAtomically(get_de_key_path(user_id), user_key_temp, |
| kEmptyAuthentication, de_key)) |
| return false; |
| } |
| |
| std::string ce_raw_ref; |
| if (is_wrapped_key_supported()) { |
| KeyBuffer ephemeral_wrapped_de_key; |
| KeyBuffer ephemeral_wrapped_ce_key; |
| |
| /* Export and install the DE keys */ |
| if (!getEphemeralWrappedKey(KeyFormat::RAW, de_key, &ephemeral_wrapped_de_key)) { |
| LOG(ERROR) << "Failed to export de_key"; |
| return false; |
| } |
| /* Export and install the CE keys */ |
| if (!getEphemeralWrappedKey(KeyFormat::RAW, ce_key, &ephemeral_wrapped_ce_key)) { |
| LOG(ERROR) << "Failed to export de_key"; |
| return false; |
| } |
| |
| de_key = std::move(ephemeral_wrapped_de_key); |
| ce_key = std::move(ephemeral_wrapped_ce_key); |
| } |
| if (!android::vold::installKey(de_key, &de_raw_ref)) return false; |
| if (!android::vold::installKey(ce_key, &ce_raw_ref)) return false; |
| s_ce_keys[user_id] = std::move(ce_key); |
| |
| s_de_key_raw_refs[user_id] = de_raw_ref; |
| s_ce_key_raw_refs[user_id] = ce_raw_ref; |
| |
| LOG(DEBUG) << "Created keys for user " << user_id; |
| return true; |
| } |
| |
| bool lookup_key_ref(const std::map<userid_t, std::string>& key_map, userid_t user_id, |
| std::string* raw_ref) { |
| auto refi = key_map.find(user_id); |
| if (refi == key_map.end()) { |
| LOG(DEBUG) << "Cannot find key for " << user_id; |
| return false; |
| } |
| *raw_ref = refi->second; |
| return true; |
| } |
| |
| static void get_data_file_encryption_modes(PolicyKeyRef* key_ref) { |
| if (!ReadDefaultFstab(&fstab_default)) { |
| PLOG(ERROR) << "Failed to open default fstab"; |
| return; |
| } |
| auto entry = android::fs_mgr::GetEntryForMountPoint(&fstab_default, DATA_MNT_POINT); |
| if (entry == nullptr) { |
| LOG(ERROR) << "get_data_file_encryption_modes::failed\n"; |
| return; |
| } |
| key_ref->contents_mode = entry->file_contents_mode; |
| key_ref->filenames_mode = entry->file_names_mode; |
| } |
| |
| static bool ensure_policy(const PolicyKeyRef& key_ref, const std::string& path) { |
| return fscrypt_policy_ensure(path.c_str(), key_ref.key_raw_ref.data(), |
| key_ref.key_raw_ref.size(), key_ref.contents_mode.c_str(), |
| key_ref.filenames_mode.c_str()) == 0; |
| } |
| |
| 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() { |
| 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(DEBUG) << "Skipping non-de-key " << entry->d_name; |
| continue; |
| } |
| userid_t user_id = std::stoi(entry->d_name); |
| if (s_de_key_raw_refs.count(user_id) == 0) { |
| auto key_path = de_dir + "/" + entry->d_name; |
| KeyBuffer key; |
| if (!android::vold::retrieveKey(key_path, kEmptyAuthentication, &key)) return false; |
| std::string raw_ref; |
| if (is_wrapped_key_supported()) { |
| KeyBuffer ephemeral_wrapped_key; |
| if (!getEphemeralWrappedKey(KeyFormat::RAW, key, &ephemeral_wrapped_key)) { |
| LOG(ERROR) << "Failed to export de_key in create_and_install_user_keys"; |
| return false; |
| } |
| key = std::move(ephemeral_wrapped_key); |
| } |
| if (!android::vold::installKey(key, &raw_ref)) return false; |
| s_de_key_raw_refs[user_id] = raw_ref; |
| LOG(DEBUG) << "Installed de key for user " << user_id; |
| } |
| } |
| // 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; |
| } |
| |
| bool fscrypt_initialize_systemwide_keys() { |
| LOG(INFO) << "fscrypt_initialize_systemwide_keys"; |
| bool wrapped_key_supported = false; |
| |
| if (s_systemwide_keys_initialized) { |
| LOG(INFO) << "Already initialized"; |
| return true; |
| } |
| |
| PolicyKeyRef device_ref; |
| wrapped_key_supported = is_wrapped_key_supported(); |
| |
| if (!android::vold::retrieveAndInstallKey(true, kEmptyAuthentication, |
| device_key_path, device_key_temp, |
| &device_ref.key_raw_ref, wrapped_key_supported)) |
| return false; |
| get_data_file_encryption_modes(&device_ref); |
| |
| std::string modestring = device_ref.contents_mode + ":" + device_ref.filenames_mode; |
| std::string mode_filename = std::string("/data") + fscrypt_key_mode; |
| if (!android::vold::writeStringToFile(modestring, mode_filename)) return false; |
| |
| std::string ref_filename = std::string("/data") + fscrypt_key_ref; |
| if (!android::vold::writeStringToFile(device_ref.key_raw_ref, ref_filename)) return false; |
| LOG(INFO) << "Wrote system DE key reference to:" << ref_filename; |
| |
| KeyBuffer per_boot_key; |
| if (!android::vold::randomKey(&per_boot_key)) return false; |
| std::string per_boot_raw_ref; |
| if (!android::vold::installKey(per_boot_key, &per_boot_raw_ref)) return false; |
| std::string per_boot_ref_filename = std::string("/data") + fscrypt_key_per_boot_ref; |
| if (!android::vold::writeStringToFile(per_boot_raw_ref, per_boot_ref_filename)) return false; |
| LOG(INFO) << "Wrote per boot key reference to:" << per_boot_ref_filename; |
| |
| if (!android::vold::FsyncDirectory(device_key_dir)) return false; |
| s_systemwide_keys_initialized = true; |
| de_raw_ref = device_ref.key_raw_ref; |
| return true; |
| } |
| |
| bool fscrypt_init_user0() { |
| if (!ReadDefaultFstab(&fstab_default)) { |
| PLOG(ERROR) << "Failed to open default fstab"; |
| return -1; |
| } |
| 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 (!android::vold::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. |
| if (!fscrypt_prepare_user_storage("", 0, 0, 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()) { |
| fscrypt_unlock_user_key(0, 0, "!", "!"); |
| } |
| |
| return true; |
| } |
| |
| bool fscrypt_vold_create_user_key(userid_t user_id, int serial, bool ephemeral) { |
| LOG(DEBUG) << "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_key_raw_refs.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; |
| } |
| |
| static void drop_caches() { |
| // Clean any dirty pages (otherwise they won't be dropped). |
| sync(); |
| // Drop inode and page caches. |
| if (!android::vold::writeStringToFile("3", "/proc/sys/vm/drop_caches")) { |
| PLOG(ERROR) << "Failed to drop caches during key eviction"; |
| } |
| } |
| |
| static bool evict_ce_key(userid_t user_id) { |
| s_ce_keys.erase(user_id); |
| bool success = true; |
| std::string raw_ref; |
| // If we haven't loaded the CE key, no need to evict it. |
| if (lookup_key_ref(s_ce_key_raw_refs, user_id, &raw_ref)) { |
| success &= android::vold::evictKey(raw_ref); |
| drop_caches(); |
| } |
| s_ce_key_raw_refs.erase(user_id); |
| return success; |
| } |
| |
| bool fscrypt_destroy_user_key(userid_t user_id) { |
| LOG(DEBUG) << "fscrypt_destroy_user_key(" << user_id << ")"; |
| if (!fscrypt_is_native()) { |
| return true; |
| } |
| bool success = true; |
| std::string raw_ref; |
| success &= evict_ce_key(user_id); |
| success &= |
| lookup_key_ref(s_de_key_raw_refs, user_id, &raw_ref) && android::vold::evictKey(raw_ref); |
| s_de_key_raw_refs.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 &= android::vold::destroyKey(path); |
| } |
| auto de_key_path = get_de_key_path(user_id); |
| if (android::vold::pathExists(de_key_path)) { |
| success &= android::vold::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 (android::vold::HexToStr(hex, *result) != 0) { |
| LOG(ERROR) << "Invalid FBE hex string"; // Don't log the string for security reasons |
| return false; |
| } |
| return true; |
| } |
| |
| 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, |
| PolicyKeyRef* key_ref) { |
| auto secdiscardable_path = volume_secdiscardable_path(volume_uuid); |
| std::string secdiscardable_hash; |
| bool wrapped_key_supported = false; |
| if (android::vold::pathExists(secdiscardable_path)) { |
| if (!android::vold::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 (!android::vold::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; |
| } |
| android::vold::KeyAuthentication auth("", secdiscardable_hash); |
| wrapped_key_supported = is_wrapped_key_supported_external(); |
| |
| if (!android::vold::retrieveAndInstallKey(true, auth, key_path, key_path + "_tmp", |
| &key_ref->key_raw_ref, wrapped_key_supported)) |
| return false; |
| key_ref->contents_mode = |
| android::base::GetProperty("ro.crypto.volume.contents_mode", "aes-256-xts"); |
| key_ref->filenames_mode = |
| android::base::GetProperty("ro.crypto.volume.filenames_mode", "aes-256-heh"); |
| 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 (!android::vold::pathExists(path)) return true; |
| return android::vold::destroyKey(path); |
| } |
| |
| bool fscrypt_add_user_key_auth(userid_t user_id, int serial, const std::string& token_hex, |
| const std::string& secret_hex) { |
| LOG(DEBUG) << "fscrypt_add_user_key_auth " << user_id << " serial=" << serial |
| << " token_present=" << (token_hex != "!"); |
| if (!fscrypt_is_native()) return true; |
| if (s_ephemeral_users.count(user_id) != 0) return true; |
| std::string token, secret; |
| if (!parse_hex(token_hex, &token)) return false; |
| if (!parse_hex(secret_hex, &secret)) return false; |
| auto auth = |
| secret.empty() ? kEmptyAuthentication : android::vold::KeyAuthentication(token, secret); |
| auto const directory_path = get_ce_key_directory_path(user_id); |
| auto const paths = get_ce_key_paths(directory_path); |
| |
| KeyBuffer ce_key; |
| if(is_wrapped_key_supported()) { |
| std::string ce_key_current_path = get_ce_key_current_path(directory_path); |
| if (android::vold::retrieveKey(ce_key_current_path, kEmptyAuthentication, &ce_key)) { |
| LOG(DEBUG) << "Successfully retrieved key"; |
| } else { |
| if (android::vold::retrieveKey(ce_key_current_path, auth, &ce_key)) { |
| LOG(DEBUG) << "Successfully retrieved key"; |
| } |
| } |
| } else { |
| auto it = s_ce_keys.find(user_id); |
| if (it == s_ce_keys.end()) { |
| LOG(ERROR) << "Key not loaded into memory, can't change for user " << user_id; |
| return false; |
| } |
| ce_key = it->second; |
| } |
| |
| std::string ce_key_path; |
| if (!get_ce_key_new_path(directory_path, paths, &ce_key_path)) return false; |
| if (!android::vold::storeKeyAtomically(ce_key_path, user_key_temp, auth, ce_key)) return false; |
| if (!android::vold::FsyncDirectory(directory_path)) return false; |
| return true; |
| } |
| |
| bool fscrypt_clear_user_key_auth(userid_t user_id, int serial, const std::string& token_hex, |
| const std::string& secret_hex) { |
| LOG(DEBUG) << "fscrypt_clear_user_key_auth " << user_id << " serial=" << serial |
| << " token_present=" << (token_hex != "!"); |
| if (!fscrypt_is_native()) return true; |
| if (s_ephemeral_users.count(user_id) != 0) return true; |
| std::string token, secret; |
| |
| if (!parse_hex(token_hex, &token)) return false; |
| if (!parse_hex(secret_hex, &secret)) return false; |
| |
| if (is_wrapped_key_supported()) { |
| auto const directory_path = get_ce_key_directory_path(user_id); |
| auto const paths = get_ce_key_paths(directory_path); |
| |
| KeyBuffer ce_key; |
| std::string ce_key_current_path = get_ce_key_current_path(directory_path); |
| |
| auto auth = android::vold::KeyAuthentication(token, secret); |
| /* Retrieve key while removing a pin. A secret is needed */ |
| if (android::vold::retrieveKey(ce_key_current_path, auth, &ce_key)) { |
| LOG(DEBUG) << "Successfully retrieved key"; |
| } else { |
| /* Retrieve key when going None to swipe and vice versa when a |
| synthetic password is present */ |
| if (android::vold::retrieveKey(ce_key_current_path, kEmptyAuthentication, &ce_key)) { |
| LOG(DEBUG) << "Successfully retrieved key"; |
| } |
| } |
| |
| std::string ce_key_path; |
| if (!get_ce_key_new_path(directory_path, paths, &ce_key_path)) return false; |
| if (!android::vold::storeKeyAtomically(ce_key_path, user_key_temp, kEmptyAuthentication, ce_key)) |
| return false; |
| } else { |
| if(!fscrypt_add_user_key_auth(user_id, serial, "!", "!")) return false; |
| } |
| return true; |
| } |
| |
| bool fscrypt_fixate_newest_user_key_auth(userid_t user_id) { |
| LOG(DEBUG) << "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(DEBUG) << "fscrypt_unlock_user_key " << user_id << " serial=" << serial |
| << " token_present=" << (token_hex != "!"); |
| if (fscrypt_is_native()) { |
| if (s_ce_key_raw_refs.count(user_id) != 0) { |
| LOG(WARNING) << "Tried to unlock already-unlocked key for user " << user_id; |
| return true; |
| } |
| std::string token, secret; |
| if (!parse_hex(token_hex, &token)) return false; |
| if (!parse_hex(secret_hex, &secret)) return false; |
| android::vold::KeyAuthentication auth(token, secret); |
| 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(android::vold::BuildDataSystemCePath(user_id), 0771) || |
| !emulated_unlock(android::vold::BuildDataMiscCePath(user_id), 01771) || |
| !emulated_unlock(android::vold::BuildDataMediaCePath("", user_id), 0770) || |
| !emulated_unlock(android::vold::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(DEBUG) << "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(android::vold::BuildDataSystemCePath(user_id)) || |
| !emulated_lock(android::vold::BuildDataMiscCePath(user_id)) || |
| !emulated_lock(android::vold::BuildDataMediaCePath("", user_id)) || |
| !emulated_lock(android::vold::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 != android::vold::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(DEBUG) << "fscrypt_prepare_user_storage for volume " << escape_empty(volume_uuid) |
| << ", user " << user_id << ", serial " << serial << ", flags " << flags; |
| |
| if (flags & STORAGE_FLAG_DE) { |
| // DE_sys key |
| auto system_legacy_path = android::vold::BuildDataSystemLegacyPath(user_id); |
| auto misc_legacy_path = android::vold::BuildDataMiscLegacyPath(user_id); |
| auto profiles_de_path = android::vold::BuildDataProfilesDePath(user_id); |
| |
| // DE_n key |
| auto system_de_path = android::vold::BuildDataSystemDePath(user_id); |
| auto misc_de_path = android::vold::BuildDataMiscDePath(user_id); |
| auto vendor_de_path = android::vold::BuildDataVendorDePath(user_id); |
| auto user_de_path = android::vold::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()) { |
| PolicyKeyRef de_ref; |
| if (volume_uuid.empty()) { |
| if (!lookup_key_ref(s_de_key_raw_refs, user_id, &de_ref.key_raw_ref)) return false; |
| get_data_file_encryption_modes(&de_ref); |
| if (!ensure_policy(de_ref, system_de_path)) return false; |
| if (!ensure_policy(de_ref, misc_de_path)) return false; |
| if (!ensure_policy(de_ref, vendor_de_path)) return false; |
| } else { |
| if (!read_or_create_volkey(misc_de_path, volume_uuid, &de_ref)) return false; |
| } |
| if (!ensure_policy(de_ref, user_de_path)) return false; |
| } |
| } |
| if (flags & STORAGE_FLAG_CE) { |
| // CE_n key |
| auto system_ce_path = android::vold::BuildDataSystemCePath(user_id); |
| auto misc_ce_path = android::vold::BuildDataMiscCePath(user_id); |
| auto vendor_ce_path = android::vold::BuildDataVendorCePath(user_id); |
| auto media_ce_path = android::vold::BuildDataMediaCePath(volume_uuid, user_id); |
| auto user_ce_path = android::vold::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()) { |
| PolicyKeyRef ce_ref; |
| if (volume_uuid.empty()) { |
| if (!lookup_key_ref(s_ce_key_raw_refs, user_id, &ce_ref.key_raw_ref)) return false; |
| get_data_file_encryption_modes(&ce_ref); |
| if (!ensure_policy(ce_ref, system_ce_path)) return false; |
| if (!ensure_policy(ce_ref, misc_ce_path)) return false; |
| if (!ensure_policy(ce_ref, vendor_ce_path)) return false; |
| |
| } else { |
| if (!read_or_create_volkey(misc_ce_path, volume_uuid, &ce_ref)) return false; |
| } |
| if (!ensure_policy(ce_ref, media_ce_path)) return false; |
| if (!ensure_policy(ce_ref, 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 |
| android::vold::RestoreconRecursive(system_ce_path); |
| android::vold::RestoreconRecursive(vendor_ce_path); |
| android::vold::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(DEBUG) << "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 & STORAGE_FLAG_CE) { |
| // CE_n key |
| auto system_ce_path = android::vold::BuildDataSystemCePath(user_id); |
| auto misc_ce_path = android::vold::BuildDataMiscCePath(user_id); |
| auto vendor_ce_path = android::vold::BuildDataVendorCePath(user_id); |
| auto media_ce_path = android::vold::BuildDataMediaCePath(volume_uuid, user_id); |
| auto user_ce_path = android::vold::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 & STORAGE_FLAG_DE) { |
| // DE_sys key |
| auto system_legacy_path = android::vold::BuildDataSystemLegacyPath(user_id); |
| auto misc_legacy_path = android::vold::BuildDataMiscLegacyPath(user_id); |
| auto profiles_de_path = android::vold::BuildDataProfilesDePath(user_id); |
| |
| // DE_n key |
| auto system_de_path = android::vold::BuildDataSystemDePath(user_id); |
| auto misc_de_path = android::vold::BuildDataMiscDePath(user_id); |
| auto vendor_de_path = android::vold::BuildDataVendorDePath(user_id); |
| auto user_de_path = android::vold::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(DEBUG) << "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(DEBUG) << "fscrypt_destroy_volume_keys for volume " << escape_empty(volume_uuid); |
| auto secdiscardable_path = volume_secdiscardable_path(volume_uuid); |
| res &= android::vold::runSecdiscardSingle(secdiscardable_path); |
| res &= destroy_volume_keys("/data/misc_ce", volume_uuid); |
| res &= destroy_volume_keys("/data/misc_de", volume_uuid); |
| return res; |
| } |