| /* |
| * 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 "Ext4CryptPie.h" |
| |
| #include "Keymaster4.h" |
| #include "KeyStorage4.h" |
| #include "KeyUtil.h" |
| #include "Utils.h" |
| #include "Decrypt.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 <unistd.h> |
| #include <limits.h> |
| #include <selinux/android.h> |
| #include <sys/mount.h> |
| #include <sys/stat.h> |
| #include <sys/types.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 <ext4_utils/ext4_crypt.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 <iostream> |
| #define LOG(x) std::cout |
| #define PLOG(x) std::cout |
| #define DATA_MNT_POINT "/data" |
| |
| using android::base::StringPrintf; |
| using android::base::WriteStringToFile; |
| using android::vold::kEmptyAuthentication; |
| using android::vold::KeyBuffer; |
| using android::vold::Keymaster; |
| using android::hardware::keymaster::V4_0::KeyFormat; |
| |
| // Store main DE raw ref / policy |
| std::string de_raw_ref; |
| // Map user ids to key references |
| std::map<userid_t, std::string> s_de_key_raw_refs; |
| std::map<userid_t, std::string> s_ce_key_raw_refs; |
| // TODO abolish this map, per b/26948053 |
| std::map<userid_t, KeyBuffer> s_ce_keys; |
| |
| 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 + e4crypt_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"; |
| |
| bool s_global_de_initialized = false; |
| |
| // Some users are ephemeral, don't try to wipe their keys from disk |
| std::set<userid_t> s_ephemeral_users; |
| |
| } |
| |
| static bool e4crypt_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 << std::endl; |
| 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 << std::endl; |
| 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 << std::endl; |
| 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"; |
| } |
| |
| // 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 << std::endl; |
| if (rename(to_fix.c_str(), current_path.c_str()) != 0) { |
| PLOG(WARNING) << "Unable to rename " << to_fix << " to " << current_path << std::endl; |
| } |
| } |
| } |
| |
| 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 << std::endl; |
| if (android::vold::retrieveKey(ce_key_path, auth, ce_key)) { |
| LOG(DEBUG) << "Successfully retrieved key" << std::endl; |
| fixate_user_ce_key(directory_path, ce_key_path, paths); |
| return true; |
| } |
| } |
| LOG(ERROR) << "Failed to find working ce key for user " << user_id << std::endl; |
| return false; |
| } |
| |
| static bool is_wrapped_key_supported_common(const std::string& mount_point) { |
| LOG(DEBUG) << "Determining wrapped-key support for " << mount_point << std::endl; |
| std::string wrapped_key_supported = android::base::GetProperty("fbe.data.wrappedkey", "false"); |
| LOG(DEBUG) << "fbe.data.wrappedkey = " << wrapped_key_supported << std::endl; |
| if (mount_point == DATA_MNT_POINT && wrapped_key_supported == "true") { |
| LOG(DEBUG) << "Wrapped key supported on " << mount_point << std::endl; |
| 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; |
| } |
| |
| 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 << std::endl; |
| return true; |
| } |
| |
| static bool prepare_dir(const std::string& dir, mode_t mode, uid_t uid, gid_t gid) { |
| LOG(DEBUG) << "Preparing: " << dir << std::endl; |
| if (fs_prepare_dir(dir.c_str(), mode, uid, gid) != 0) { |
| PLOG(ERROR) << "Failed to prepare " << dir << std::endl; |
| 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 (!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 de_raw_ref; |
| if (!android::vold::installKey(de_key, &de_raw_ref)) return false; |
| s_de_key_raw_refs[user_id] = de_raw_ref; |
| std::string ce_raw_ref; |
| if (!android::vold::installKey(ce_key, &ce_raw_ref)) return false; |
| s_ce_keys[user_id] = ce_key; |
| s_ce_key_raw_refs[user_id] = ce_raw_ref; |
| LOG(DEBUG) << "Created keys for user " << user_id;*/ |
| LOG(DEBUG) << "TWRP not doing create_and_install_user_keys\n"; |
| 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(ERROR) << "Cannot find key for " << user_id << std::endl; |
| return false; |
| } |
| *raw_ref = refi->second; |
| return true; |
| } |
| |
| static void get_data_file_encryption_modes(PolicyKeyRef* key_ref) { |
| /*struct fstab_rec* rec = fs_mgr_get_entry_for_mount_point(fstab_default, DATA_MNT_POINT); |
| char const* contents_mode = strdup("ice"); |
| char const* filenames_mode = strdup("aes-256-heh"); |
| fs_mgr_get_file_encryption_modes(rec, &contents_mode, &filenames_mode); |
| key_ref->contents_mode = contents_mode; |
| key_ref->filenames_mode = filenames_mode;*/ |
| LOG(INFO) << "contents mode '" << android::base::GetProperty("fbe.contents", "aes-256-xts") << "' filenames '" << android::base::GetProperty("fbe.filenames", "aes-256-heh") << "'\n"; |
| key_ref->contents_mode = |
| android::base::GetProperty("fbe.contents", "aes-256-xts"); |
| key_ref->filenames_mode = |
| android::base::GetProperty("fbe.filenames", "aes-256-heh"); |
| } |
| |
| 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" << std::endl; |
| return false; |
| } |
| for (;;) { |
| errno = 0; |
| auto entry = readdir(dirp.get()); |
| if (!entry) { |
| if (errno) { |
| PLOG(ERROR) << "Unable to read de key directory" << std::endl; |
| return false; |
| } |
| break; |
| } |
| if (entry->d_type != DT_DIR || !is_numeric(entry->d_name)) { |
| LOG(DEBUG) << "Skipping non-de-key " << entry->d_name << std::endl; |
| 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 << std::endl; |
| |
| std::string user_prop = "twrp.user." + std::to_string(user_id) + ".decrypt"; |
| property_set(user_prop.c_str(), "0"); |
| } |
| } |
| // ext4enc: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 e4crypt_initialize_global_de() { |
| LOG(INFO) << "e4crypt_initialize_global_de" << std::endl; |
| bool wrapped_key_supported = false; |
| |
| if (s_global_de_initialized) { |
| LOG(INFO) << "Already initialized" << std::endl; |
| return true; |
| } |
| |
| PolicyKeyRef device_ref; |
| wrapped_key_supported = is_wrapped_key_supported(); |
| LOG(INFO) << "calling retrieveAndInstallKey\n"; |
| 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") + e4crypt_key_mode; |
| if (!android::base::WriteStringToFile(modestring, mode_filename)) { |
| PLOG(ERROR) << "Cannot save type" << std::endl; |
| return false; |
| } |
| |
| std::string ref_filename = std::string("/data") + e4crypt_key_ref; |
| if (!android::base::WriteStringToFile(device_ref.key_raw_ref, ref_filename)) { |
| PLOG(ERROR) << "Cannot save key reference to:" << ref_filename << std::endl; |
| return false; |
| } |
| LOG(INFO) << "Wrote system DE key reference to:" << ref_filename << std::endl; |
| |
| s_global_de_initialized = true; |
| de_raw_ref = device_ref.key_raw_ref; |
| return true; |
| } |
| |
| bool e4crypt_init_user0() { |
| LOG(DEBUG) << "e4crypt_init_user0\n"; |
| if (e4crypt_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; |
| } |
| |
| // If this is a non-FBE device that recently left an emulated mode, |
| // restore user data directories to known-good state. |
| if (!e4crypt_is_native() && !e4crypt_is_emulated()) { |
| e4crypt_unlock_user_key(0, 0, "!", "!"); |
| } |
| |
| 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 << std::endl; |
| // FIXME temporary workaround for b/26713622 |
| if (e4crypt_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 << std::endl; |
| // FIXME temporary workaround for b/26713622 |
| if (e4crypt_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" << std::endl; // Don't log the string for security reasons |
| return false; |
| } |
| return true; |
| } |
| |
| // TODO: rename to 'install' for consistency, and take flags to know which keys to install |
| bool e4crypt_unlock_user_key(userid_t user_id, int serial, const std::string& token_hex, |
| const std::string& secret_hex) { |
| LOG(DEBUG) << "e4crypt_unlock_user_key " << user_id << " serial=" << serial |
| << " token_present=" << (token_hex != "!") << std::endl; |
| if (e4crypt_is_native()) { |
| if (s_ce_key_raw_refs.count(user_id) != 0) { |
| LOG(WARNING) << "Tried to unlock already-unlocked key for user " << user_id << std::endl; |
| 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 << std::endl; |
| 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 << std::endl; |
| return false; |
| } |
| } |
| return true; |
| } |