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995 lines
40 KiB
995 lines
40 KiB
/*
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* Copyright (C) 2015 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "FsCrypt.h"
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#include "KeyStorage.h"
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#include "KeyUtil.h"
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#include "Utils.h"
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#include "VoldUtil.h"
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#include <algorithm>
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#include <map>
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#include <optional>
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#include <set>
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#include <sstream>
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#include <string>
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#include <vector>
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#include <dirent.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <limits.h>
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#include <selinux/android.h>
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#include <sys/mount.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include <private/android_filesystem_config.h>
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#include <private/android_projectid_config.h>
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#include "android/os/IVold.h"
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#define EMULATED_USES_SELINUX 0
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#define MANAGE_MISC_DIRS 0
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#include <cutils/fs.h>
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#include <cutils/properties.h>
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#include <fscrypt/fscrypt.h>
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#include <keyutils.h>
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#include <libdm/dm.h>
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#include <android-base/file.h>
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#include <android-base/logging.h>
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#include <android-base/properties.h>
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#include <android-base/stringprintf.h>
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#include <android-base/strings.h>
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#include <android-base/unique_fd.h>
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using android::base::Basename;
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using android::base::Realpath;
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using android::base::StartsWith;
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using android::base::StringPrintf;
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using android::fs_mgr::GetEntryForMountPoint;
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using android::vold::BuildDataPath;
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using android::vold::IsDotOrDotDot;
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using android::vold::IsFilesystemSupported;
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using android::vold::kEmptyAuthentication;
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using android::vold::KeyBuffer;
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using android::vold::KeyGeneration;
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using android::vold::retrieveKey;
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using android::vold::retrieveOrGenerateKey;
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using android::vold::SetDefaultAcl;
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using android::vold::SetQuotaInherit;
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using android::vold::SetQuotaProjectId;
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using android::vold::writeStringToFile;
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using namespace android::fscrypt;
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using namespace android::dm;
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namespace {
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const std::string device_key_dir = std::string() + DATA_MNT_POINT + fscrypt_unencrypted_folder;
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const std::string device_key_path = device_key_dir + "/key";
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const std::string device_key_temp = device_key_dir + "/temp";
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const std::string user_key_dir = std::string() + DATA_MNT_POINT + "/misc/vold/user_keys";
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const std::string user_key_temp = user_key_dir + "/temp";
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const std::string prepare_subdirs_path = "/system/bin/vold_prepare_subdirs";
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const std::string systemwide_volume_key_dir =
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std::string() + DATA_MNT_POINT + "/misc/vold/volume_keys";
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// Some users are ephemeral, don't try to wipe their keys from disk
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std::set<userid_t> s_ephemeral_users;
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// Map user ids to encryption policies
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std::map<userid_t, EncryptionPolicy> s_de_policies;
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std::map<userid_t, EncryptionPolicy> s_ce_policies;
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} // namespace
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// Returns KeyGeneration suitable for key as described in EncryptionOptions
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static KeyGeneration makeGen(const EncryptionOptions& options) {
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return KeyGeneration{FSCRYPT_MAX_KEY_SIZE, true, options.use_hw_wrapped_key};
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}
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static bool fscrypt_is_emulated() {
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return property_get_bool("persist.sys.emulate_fbe", false);
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}
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static const char* escape_empty(const std::string& value) {
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return value.empty() ? "null" : value.c_str();
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}
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static std::string get_de_key_path(userid_t user_id) {
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return StringPrintf("%s/de/%d", user_key_dir.c_str(), user_id);
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}
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static std::string get_ce_key_directory_path(userid_t user_id) {
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return StringPrintf("%s/ce/%d", user_key_dir.c_str(), user_id);
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}
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// Returns the keys newest first
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static std::vector<std::string> get_ce_key_paths(const std::string& directory_path) {
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auto dirp = std::unique_ptr<DIR, int (*)(DIR*)>(opendir(directory_path.c_str()), closedir);
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if (!dirp) {
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PLOG(ERROR) << "Unable to open ce key directory: " + directory_path;
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return std::vector<std::string>();
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}
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std::vector<std::string> result;
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for (;;) {
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errno = 0;
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auto const entry = readdir(dirp.get());
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if (!entry) {
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if (errno) {
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PLOG(ERROR) << "Unable to read ce key directory: " + directory_path;
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return std::vector<std::string>();
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}
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break;
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}
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if (IsDotOrDotDot(*entry)) continue;
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if (entry->d_type != DT_DIR || entry->d_name[0] != 'c') {
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LOG(DEBUG) << "Skipping non-key " << entry->d_name;
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continue;
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}
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result.emplace_back(directory_path + "/" + entry->d_name);
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}
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std::sort(result.begin(), result.end());
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std::reverse(result.begin(), result.end());
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return result;
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}
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static std::string get_ce_key_current_path(const std::string& directory_path) {
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return directory_path + "/current";
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}
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static bool get_ce_key_new_path(const std::string& directory_path,
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const std::vector<std::string>& paths, std::string* ce_key_path) {
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if (paths.empty()) {
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*ce_key_path = get_ce_key_current_path(directory_path);
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return true;
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}
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for (unsigned int i = 0; i < UINT_MAX; i++) {
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auto const candidate = StringPrintf("%s/cx%010u", directory_path.c_str(), i);
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if (paths[0] < candidate) {
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*ce_key_path = candidate;
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return true;
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}
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}
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return false;
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}
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// Discard all keys but the named one; rename it to canonical name.
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// No point in acting on errors in this; ignore them.
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static void fixate_user_ce_key(const std::string& directory_path, const std::string& to_fix,
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const std::vector<std::string>& paths) {
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for (auto const other_path : paths) {
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if (other_path != to_fix) {
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android::vold::destroyKey(other_path);
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}
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}
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auto const current_path = get_ce_key_current_path(directory_path);
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if (to_fix != current_path) {
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LOG(DEBUG) << "Renaming " << to_fix << " to " << current_path;
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if (rename(to_fix.c_str(), current_path.c_str()) != 0) {
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PLOG(WARNING) << "Unable to rename " << to_fix << " to " << current_path;
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return;
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}
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}
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android::vold::FsyncDirectory(directory_path);
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}
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static bool read_and_fixate_user_ce_key(userid_t user_id,
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const android::vold::KeyAuthentication& auth,
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KeyBuffer* ce_key) {
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auto const directory_path = get_ce_key_directory_path(user_id);
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auto const paths = get_ce_key_paths(directory_path);
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for (auto const ce_key_path : paths) {
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LOG(DEBUG) << "Trying user CE key " << ce_key_path;
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if (retrieveKey(ce_key_path, auth, ce_key)) {
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LOG(DEBUG) << "Successfully retrieved key";
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fixate_user_ce_key(directory_path, ce_key_path, paths);
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return true;
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}
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}
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LOG(ERROR) << "Failed to find working ce key for user " << user_id;
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return false;
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}
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static bool IsEmmcStorage(const std::string& blk_device) {
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// Handle symlinks.
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std::string real_path;
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if (!Realpath(blk_device, &real_path)) {
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real_path = blk_device;
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}
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// Handle logical volumes.
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auto& dm = DeviceMapper::Instance();
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for (;;) {
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auto parent = dm.GetParentBlockDeviceByPath(real_path);
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if (!parent.has_value()) break;
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real_path = *parent;
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}
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// Now we should have the "real" block device.
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LOG(DEBUG) << "IsEmmcStorage(): blk_device = " << blk_device << ", real_path=" << real_path;
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return StartsWith(Basename(real_path), "mmcblk");
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}
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// Retrieve the options to use for encryption policies on the /data filesystem.
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static bool get_data_file_encryption_options(EncryptionOptions* options) {
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auto entry = GetEntryForMountPoint(&fstab_default, DATA_MNT_POINT);
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if (entry == nullptr) {
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LOG(ERROR) << "No mount point entry for " << DATA_MNT_POINT;
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return false;
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}
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if (!ParseOptions(entry->encryption_options, options)) {
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LOG(ERROR) << "Unable to parse encryption options for " << DATA_MNT_POINT ": "
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<< entry->encryption_options;
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return false;
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}
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if ((options->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32) &&
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!IsEmmcStorage(entry->blk_device)) {
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LOG(ERROR) << "The emmc_optimized encryption flag is only allowed on eMMC storage. Remove "
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"this flag from the device's fstab";
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return false;
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}
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return true;
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}
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static bool install_storage_key(const std::string& mountpoint, const EncryptionOptions& options,
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const KeyBuffer& key, EncryptionPolicy* policy) {
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KeyBuffer ephemeral_wrapped_key;
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if (options.use_hw_wrapped_key) {
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if (!exportWrappedStorageKey(key, &ephemeral_wrapped_key)) {
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LOG(ERROR) << "Failed to get ephemeral wrapped key";
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return false;
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}
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}
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return installKey(mountpoint, options, options.use_hw_wrapped_key ? ephemeral_wrapped_key : key,
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policy);
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}
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// Retrieve the options to use for encryption policies on adoptable storage.
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static bool get_volume_file_encryption_options(EncryptionOptions* options) {
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// If we give the empty string, libfscrypt will use the default (currently XTS)
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auto contents_mode = android::base::GetProperty("ro.crypto.volume.contents_mode", "");
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// HEH as default was always a mistake. Use the libfscrypt default (CTS)
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// for devices launching on versions above Android 10.
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auto first_api_level = GetFirstApiLevel();
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auto filenames_mode =
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android::base::GetProperty("ro.crypto.volume.filenames_mode",
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first_api_level > __ANDROID_API_Q__ ? "" : "aes-256-heh");
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auto options_string = android::base::GetProperty("ro.crypto.volume.options",
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contents_mode + ":" + filenames_mode);
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if (!ParseOptionsForApiLevel(first_api_level, options_string, options)) {
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LOG(ERROR) << "Unable to parse volume encryption options: " << options_string;
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return false;
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}
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if (options->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32) {
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LOG(ERROR) << "The emmc_optimized encryption flag is only allowed on eMMC storage. Remove "
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"this flag from ro.crypto.volume.options";
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return false;
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}
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return true;
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}
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static bool read_and_install_user_ce_key(userid_t user_id,
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const android::vold::KeyAuthentication& auth) {
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if (s_ce_policies.count(user_id) != 0) return true;
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EncryptionOptions options;
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if (!get_data_file_encryption_options(&options)) return false;
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KeyBuffer ce_key;
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if (!read_and_fixate_user_ce_key(user_id, auth, &ce_key)) return false;
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EncryptionPolicy ce_policy;
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if (!install_storage_key(DATA_MNT_POINT, options, ce_key, &ce_policy)) return false;
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s_ce_policies[user_id] = ce_policy;
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LOG(DEBUG) << "Installed ce key for user " << user_id;
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return true;
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}
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static bool prepare_dir(const std::string& dir, mode_t mode, uid_t uid, gid_t gid) {
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LOG(DEBUG) << "Preparing: " << dir;
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if (fs_prepare_dir(dir.c_str(), mode, uid, gid) != 0) {
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PLOG(ERROR) << "Failed to prepare " << dir;
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return false;
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}
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return true;
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}
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static bool destroy_dir(const std::string& dir) {
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LOG(DEBUG) << "Destroying: " << dir;
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if (rmdir(dir.c_str()) != 0 && errno != ENOENT) {
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PLOG(ERROR) << "Failed to destroy " << dir;
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return false;
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}
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return true;
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}
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// NB this assumes that there is only one thread listening for crypt commands, because
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// it creates keys in a fixed location.
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static bool create_and_install_user_keys(userid_t user_id, bool create_ephemeral) {
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EncryptionOptions options;
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if (!get_data_file_encryption_options(&options)) return false;
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KeyBuffer de_key, ce_key;
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if (!generateStorageKey(makeGen(options), &de_key)) return false;
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if (!generateStorageKey(makeGen(options), &ce_key)) return false;
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if (create_ephemeral) {
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// If the key should be created as ephemeral, don't store it.
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s_ephemeral_users.insert(user_id);
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} else {
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auto const directory_path = get_ce_key_directory_path(user_id);
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if (!prepare_dir(directory_path, 0700, AID_ROOT, AID_ROOT)) return false;
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auto const paths = get_ce_key_paths(directory_path);
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std::string ce_key_path;
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if (!get_ce_key_new_path(directory_path, paths, &ce_key_path)) return false;
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if (!android::vold::storeKeyAtomically(ce_key_path, user_key_temp, kEmptyAuthentication,
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ce_key))
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return false;
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fixate_user_ce_key(directory_path, ce_key_path, paths);
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// Write DE key second; once this is written, all is good.
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if (!android::vold::storeKeyAtomically(get_de_key_path(user_id), user_key_temp,
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kEmptyAuthentication, de_key))
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return false;
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}
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EncryptionPolicy de_policy;
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if (!install_storage_key(DATA_MNT_POINT, options, de_key, &de_policy)) return false;
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s_de_policies[user_id] = de_policy;
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EncryptionPolicy ce_policy;
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if (!install_storage_key(DATA_MNT_POINT, options, ce_key, &ce_policy)) return false;
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s_ce_policies[user_id] = ce_policy;
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LOG(DEBUG) << "Created keys for user " << user_id;
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return true;
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}
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static bool lookup_policy(const std::map<userid_t, EncryptionPolicy>& key_map, userid_t user_id,
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EncryptionPolicy* policy) {
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auto refi = key_map.find(user_id);
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if (refi == key_map.end()) {
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LOG(DEBUG) << "Cannot find key for " << user_id;
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return false;
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}
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*policy = refi->second;
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return true;
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}
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static bool is_numeric(const char* name) {
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for (const char* p = name; *p != '\0'; p++) {
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if (!isdigit(*p)) return false;
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}
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return true;
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}
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static bool load_all_de_keys() {
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EncryptionOptions options;
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if (!get_data_file_encryption_options(&options)) return false;
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auto de_dir = user_key_dir + "/de";
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auto dirp = std::unique_ptr<DIR, int (*)(DIR*)>(opendir(de_dir.c_str()), closedir);
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if (!dirp) {
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PLOG(ERROR) << "Unable to read de key directory";
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return false;
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}
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for (;;) {
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errno = 0;
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auto entry = readdir(dirp.get());
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if (!entry) {
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if (errno) {
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PLOG(ERROR) << "Unable to read de key directory";
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return false;
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}
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break;
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}
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if (IsDotOrDotDot(*entry)) continue;
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if (entry->d_type != DT_DIR || !is_numeric(entry->d_name)) {
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LOG(DEBUG) << "Skipping non-de-key " << entry->d_name;
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continue;
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}
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userid_t user_id = std::stoi(entry->d_name);
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auto key_path = de_dir + "/" + entry->d_name;
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KeyBuffer de_key;
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if (!retrieveKey(key_path, kEmptyAuthentication, &de_key)) return false;
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EncryptionPolicy de_policy;
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if (!install_storage_key(DATA_MNT_POINT, options, de_key, &de_policy)) return false;
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auto ret = s_de_policies.insert({user_id, de_policy});
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if (!ret.second && ret.first->second != de_policy) {
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LOG(ERROR) << "DE policy for user" << user_id << " changed";
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return false;
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}
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LOG(DEBUG) << "Installed de key for user " << user_id;
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}
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// fscrypt:TODO: go through all DE directories, ensure that all user dirs have the
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// correct policy set on them, and that no rogue ones exist.
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return true;
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}
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// Attempt to reinstall CE keys for users that we think are unlocked.
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static bool try_reload_ce_keys() {
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for (const auto& it : s_ce_policies) {
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if (!android::vold::reloadKeyFromSessionKeyring(DATA_MNT_POINT, it.second)) {
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LOG(ERROR) << "Failed to load CE key from session keyring for user " << it.first;
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return false;
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}
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}
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return true;
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}
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bool fscrypt_initialize_systemwide_keys() {
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LOG(INFO) << "fscrypt_initialize_systemwide_keys";
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EncryptionOptions options;
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if (!get_data_file_encryption_options(&options)) return false;
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KeyBuffer device_key;
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if (!retrieveOrGenerateKey(device_key_path, device_key_temp, kEmptyAuthentication,
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makeGen(options), &device_key))
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return false;
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EncryptionPolicy device_policy;
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if (!install_storage_key(DATA_MNT_POINT, options, device_key, &device_policy)) return false;
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std::string options_string;
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if (!OptionsToString(device_policy.options, &options_string)) {
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LOG(ERROR) << "Unable to serialize options";
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return false;
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}
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std::string options_filename = std::string(DATA_MNT_POINT) + fscrypt_key_mode;
|
|
if (!android::vold::writeStringToFile(options_string, options_filename)) return false;
|
|
|
|
std::string ref_filename = std::string(DATA_MNT_POINT) + fscrypt_key_ref;
|
|
if (!android::vold::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 (!android::vold::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;
|
|
|
|
return true;
|
|
}
|
|
|
|
bool fscrypt_init_user0() {
|
|
LOG(DEBUG) << "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 (!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, 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()) {
|
|
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() && android::vold::isFsKeyringSupported()) {
|
|
if (!try_reload_ce_keys()) return false;
|
|
}
|
|
|
|
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_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 (android::vold::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 &= android::vold::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(DEBUG) << "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) &&
|
|
android::vold::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 &= 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::optional<android::vold::KeyAuthentication> authentication_from_hex(
|
|
const std::string& secret_hex) {
|
|
std::string secret;
|
|
if (!parse_hex(secret_hex, &secret)) return std::optional<android::vold::KeyAuthentication>();
|
|
if (secret.empty()) {
|
|
return kEmptyAuthentication;
|
|
} else {
|
|
return android::vold::KeyAuthentication(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 (android::vold::pathExists(secdiscardable_path)) {
|
|
if (!android::vold::readSecdiscardable(secdiscardable_path, &secdiscardable_hash))
|
|
return false;
|
|
} else {
|
|
if (!android::vold::MkdirsSync(secdiscardable_path, 0700)) return false;
|
|
if (!android::vold::createSecdiscardable(secdiscardable_path, &secdiscardable_hash))
|
|
return false;
|
|
}
|
|
auto key_path = volkey_path(misc_path, volume_uuid);
|
|
if (!android::vold::MkdirsSync(key_path, 0700)) return false;
|
|
android::vold::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 (!android::vold::pathExists(path)) return true;
|
|
return android::vold::destroyKey(path);
|
|
}
|
|
|
|
static bool fscrypt_rewrap_user_key(userid_t user_id, int serial,
|
|
const android::vold::KeyAuthentication& retrieve_auth,
|
|
const android::vold::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)) {
|
|
LOG(DEBUG) << "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)) {
|
|
LOG(DEBUG) << "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 (!android::vold::storeKeyAtomically(ce_key_path, user_key_temp, store_auth, ce_key))
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
bool fscrypt_add_user_key_auth(userid_t user_id, int serial, const std::string& secret_hex) {
|
|
LOG(DEBUG) << "fscrypt_add_user_key_auth " << user_id << " serial=" << serial;
|
|
if (!fscrypt_is_native()) return true;
|
|
auto auth = authentication_from_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& secret_hex) {
|
|
LOG(DEBUG) << "fscrypt_clear_user_key_auth " << user_id << " serial=" << serial;
|
|
if (!fscrypt_is_native()) return true;
|
|
auto auth = authentication_from_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(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;
|
|
}
|
|
|
|
std::vector<int> fscrypt_get_unlocked_users() {
|
|
std::vector<int> user_ids;
|
|
for (const auto& it : s_ce_policies) {
|
|
user_ids.push_back(it.first);
|
|
}
|
|
return user_ids;
|
|
}
|
|
|
|
// 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& secret_hex) {
|
|
LOG(DEBUG) << "fscrypt_unlock_user_key " << user_id << " serial=" << serial;
|
|
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(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(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 & android::os::IVold::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()) {
|
|
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 = 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, 02770, AID_MEDIA_RW, AID_MEDIA_RW)) return false;
|
|
// On devices without sdcardfs (kernel 5.4+), the path permissions aren't fixed
|
|
// up automatically; therefore, use a default ACL, to ensure apps with MEDIA_RW
|
|
// can keep reading external storage; in particular, this allows app cloning
|
|
// scenarios to work correctly on such devices.
|
|
int ret = SetDefaultAcl(media_ce_path, 02770, AID_MEDIA_RW, AID_MEDIA_RW, {AID_MEDIA_RW});
|
|
if (ret != android::OK) {
|
|
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
|
|
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 & android::os::IVold::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 & android::os::IVold::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 (IsDotOrDotDot(*entry)) continue;
|
|
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;
|
|
}
|