28eddbd2ef
Vold incorrectly sends the earlyBootEnded signal only to the Keymaster instance used for device encryption, but all of them need it. Bug: 152932559 Test: VtsHalKeymasterV4_1TargetTest Merged-In: Id8f01a1dc7d2398395f369c3ea74656a82888829 Change-Id: Id8f01a1dc7d2398395f369c3ea74656a82888829
366 lines
13 KiB
C++
366 lines
13 KiB
C++
/*
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* Copyright (C) 2016 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 "MetadataCrypt.h"
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#include "KeyBuffer.h"
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#include <algorithm>
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#include <string>
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#include <thread>
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#include <vector>
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#include <fcntl.h>
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#include <sys/param.h>
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#include <sys/stat.h>
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#include <sys/types.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/strings.h>
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#include <android-base/unique_fd.h>
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#include <cutils/fs.h>
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#include <fs_mgr.h>
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#include <libdm/dm.h>
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#include "Checkpoint.h"
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#include "CryptoType.h"
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#include "EncryptInplace.h"
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#include "KeyStorage.h"
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#include "KeyUtil.h"
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#include "Keymaster.h"
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#include "Utils.h"
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#include "VoldUtil.h"
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#define TABLE_LOAD_RETRIES 10
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namespace android {
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namespace vold {
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using android::fs_mgr::FstabEntry;
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using android::fs_mgr::GetEntryForMountPoint;
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using android::vold::KeyBuffer;
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using namespace android::dm;
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// Parsed from metadata options
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struct CryptoOptions {
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struct CryptoType cipher = invalid_crypto_type;
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bool use_legacy_options_format = false;
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bool set_dun = true; // Non-legacy driver always sets DUN
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bool use_hw_wrapped_key = false;
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};
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static const std::string kDmNameUserdata = "userdata";
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static const char* kFn_keymaster_key_blob = "keymaster_key_blob";
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static const char* kFn_keymaster_key_blob_upgraded = "keymaster_key_blob_upgraded";
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// The first entry in this table is the default crypto type.
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constexpr CryptoType supported_crypto_types[] = {aes_256_xts, adiantum};
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static_assert(validateSupportedCryptoTypes(64, supported_crypto_types,
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array_length(supported_crypto_types)),
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"We have a CryptoType which was incompletely constructed.");
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constexpr CryptoType legacy_aes_256_xts =
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CryptoType().set_config_name("aes-256-xts").set_kernel_name("AES-256-XTS").set_keysize(64);
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static_assert(isValidCryptoType(64, legacy_aes_256_xts),
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"We have a CryptoType which was incompletely constructed.");
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// Returns KeyGeneration suitable for key as described in CryptoOptions
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const KeyGeneration makeGen(const CryptoOptions& options) {
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return KeyGeneration{options.cipher.get_keysize(), true, options.use_hw_wrapped_key};
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}
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static bool mount_via_fs_mgr(const char* mount_point, const char* blk_device) {
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// We're about to mount data not verified by verified boot. Tell Keymaster instances that early
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// boot has ended.
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::android::vold::Keymaster::earlyBootEnded();
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// fs_mgr_do_mount runs fsck. Use setexeccon to run trusted
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// partitions in the fsck domain.
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if (setexeccon(android::vold::sFsckContext)) {
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PLOG(ERROR) << "Failed to setexeccon";
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return false;
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}
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auto mount_rc = fs_mgr_do_mount(&fstab_default, const_cast<char*>(mount_point),
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const_cast<char*>(blk_device), nullptr,
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android::vold::cp_needsCheckpoint());
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if (setexeccon(nullptr)) {
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PLOG(ERROR) << "Failed to clear setexeccon";
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return false;
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}
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if (mount_rc != 0) {
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LOG(ERROR) << "fs_mgr_do_mount failed with rc " << mount_rc;
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return false;
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}
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LOG(DEBUG) << "Mounted " << mount_point;
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return true;
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}
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// Note: It is possible to orphan a key if it is removed before deleting
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// Update this once keymaster APIs change, and we have a proper commit.
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static void commit_key(const std::string& dir) {
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while (!android::base::WaitForProperty("vold.checkpoint_committed", "1")) {
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LOG(ERROR) << "Wait for boot timed out";
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}
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Keymaster keymaster;
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auto keyPath = dir + "/" + kFn_keymaster_key_blob;
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auto newKeyPath = dir + "/" + kFn_keymaster_key_blob_upgraded;
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std::string key;
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if (!android::base::ReadFileToString(keyPath, &key)) {
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LOG(ERROR) << "Failed to read old key: " << dir;
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return;
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}
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if (rename(newKeyPath.c_str(), keyPath.c_str()) != 0) {
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PLOG(ERROR) << "Unable to move upgraded key to location: " << keyPath;
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return;
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}
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if (!keymaster.deleteKey(key)) {
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LOG(ERROR) << "Key deletion failed during upgrade, continuing anyway: " << dir;
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}
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LOG(INFO) << "Old Key deleted: " << dir;
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}
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static bool read_key(const std::string& metadata_key_dir, const KeyGeneration& gen,
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KeyBuffer* key) {
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if (metadata_key_dir.empty()) {
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LOG(ERROR) << "Failed to get metadata_key_dir";
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return false;
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}
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std::string sKey;
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auto dir = metadata_key_dir + "/key";
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LOG(DEBUG) << "metadata_key_dir/key: " << dir;
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if (fs_mkdirs(dir.c_str(), 0700)) {
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PLOG(ERROR) << "Creating directories: " << dir;
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return false;
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}
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auto temp = metadata_key_dir + "/tmp";
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auto newKeyPath = dir + "/" + kFn_keymaster_key_blob_upgraded;
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/* If we have a leftover upgraded key, delete it.
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* We either failed an update and must return to the old key,
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* or we rebooted before commiting the keys in a freak accident.
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* Either way, we can re-upgrade the key if we need to.
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*/
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Keymaster keymaster;
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if (pathExists(newKeyPath)) {
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if (!android::base::ReadFileToString(newKeyPath, &sKey))
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LOG(ERROR) << "Failed to read incomplete key: " << dir;
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else if (!keymaster.deleteKey(sKey))
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LOG(ERROR) << "Incomplete key deletion failed, continuing anyway: " << dir;
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else
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unlink(newKeyPath.c_str());
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}
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bool needs_cp = cp_needsCheckpoint();
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if (!retrieveOrGenerateKey(dir, temp, kEmptyAuthentication, gen, key, needs_cp)) return false;
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if (needs_cp && pathExists(newKeyPath)) std::thread(commit_key, dir).detach();
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return true;
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}
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static bool get_number_of_sectors(const std::string& real_blkdev, uint64_t* nr_sec) {
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if (android::vold::GetBlockDev512Sectors(real_blkdev, nr_sec) != android::OK) {
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PLOG(ERROR) << "Unable to measure size of " << real_blkdev;
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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 create_crypto_blk_dev(const std::string& dm_name, const std::string& blk_device,
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const KeyBuffer& key, const CryptoOptions& options,
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std::string* crypto_blkdev, uint64_t* nr_sec) {
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if (!get_number_of_sectors(blk_device, nr_sec)) return false;
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// TODO(paulcrowley): don't hardcode that DmTargetDefaultKey uses 4096-byte
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// sectors
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*nr_sec &= ~7;
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KeyBuffer module_key;
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if (options.use_hw_wrapped_key) {
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if (!exportWrappedStorageKey(key, &module_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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} else {
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module_key = key;
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}
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KeyBuffer hex_key_buffer;
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if (android::vold::StrToHex(module_key, hex_key_buffer) != android::OK) {
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LOG(ERROR) << "Failed to turn key to hex";
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return false;
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}
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std::string hex_key(hex_key_buffer.data(), hex_key_buffer.size());
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auto target = std::make_unique<DmTargetDefaultKey>(0, *nr_sec, options.cipher.get_kernel_name(),
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hex_key, blk_device, 0);
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if (options.use_legacy_options_format) target->SetUseLegacyOptionsFormat();
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if (options.set_dun) target->SetSetDun();
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if (options.use_hw_wrapped_key) target->SetWrappedKeyV0();
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DmTable table;
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table.AddTarget(std::move(target));
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auto& dm = DeviceMapper::Instance();
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for (int i = 0;; i++) {
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if (dm.CreateDevice(dm_name, table)) {
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break;
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}
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if (i + 1 >= TABLE_LOAD_RETRIES) {
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PLOG(ERROR) << "Could not create default-key device " << dm_name;
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return false;
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}
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PLOG(INFO) << "Could not create default-key device, retrying";
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usleep(500000);
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}
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if (!dm.GetDmDevicePathByName(dm_name, crypto_blkdev)) {
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LOG(ERROR) << "Cannot retrieve default-key device status " << dm_name;
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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 const CryptoType& lookup_cipher(const std::string& cipher_name) {
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if (cipher_name.empty()) return supported_crypto_types[0];
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for (size_t i = 0; i < array_length(supported_crypto_types); i++) {
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if (cipher_name == supported_crypto_types[i].get_config_name()) {
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return supported_crypto_types[i];
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}
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}
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return invalid_crypto_type;
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}
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static bool parse_options(const std::string& options_string, CryptoOptions* options) {
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auto parts = android::base::Split(options_string, ":");
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if (parts.size() < 1 || parts.size() > 2) {
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LOG(ERROR) << "Invalid metadata encryption option: " << options_string;
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return false;
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}
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std::string cipher_name = parts[0];
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options->cipher = lookup_cipher(cipher_name);
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if (options->cipher.get_kernel_name() == nullptr) {
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LOG(ERROR) << "No metadata cipher named " << cipher_name << " found";
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return false;
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}
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if (parts.size() == 2) {
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if (parts[1] == "wrappedkey_v0") {
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options->use_hw_wrapped_key = true;
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} else {
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LOG(ERROR) << "Invalid metadata encryption flag: " << parts[1];
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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_mount_metadata_encrypted(const std::string& blk_device, const std::string& mount_point,
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bool needs_encrypt) {
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LOG(DEBUG) << "fscrypt_mount_metadata_encrypted: " << mount_point << " " << needs_encrypt;
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auto encrypted_state = android::base::GetProperty("ro.crypto.state", "");
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if (encrypted_state != "" && encrypted_state != "encrypted") {
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LOG(DEBUG) << "fscrypt_enable_crypto got unexpected starting state: " << encrypted_state;
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return false;
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}
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auto data_rec = GetEntryForMountPoint(&fstab_default, mount_point);
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if (!data_rec) {
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LOG(ERROR) << "Failed to get data_rec for " << mount_point;
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return false;
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}
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constexpr unsigned int pre_gki_level = 29;
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unsigned int options_format_version = android::base::GetUintProperty<unsigned int>(
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"ro.crypto.dm_default_key.options_format.version",
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(GetFirstApiLevel() <= pre_gki_level ? 1 : 2));
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CryptoOptions options;
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if (options_format_version == 1) {
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if (!data_rec->metadata_encryption.empty()) {
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LOG(ERROR) << "metadata_encryption options cannot be set in legacy mode";
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return false;
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}
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options.cipher = legacy_aes_256_xts;
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options.use_legacy_options_format = true;
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options.set_dun = android::base::GetBoolProperty("ro.crypto.set_dun", false);
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if (!options.set_dun && data_rec->fs_mgr_flags.checkpoint_blk) {
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LOG(ERROR)
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<< "Block checkpoints and metadata encryption require ro.crypto.set_dun option";
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return false;
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}
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} else if (options_format_version == 2) {
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if (!parse_options(data_rec->metadata_encryption, &options)) return false;
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} else {
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LOG(ERROR) << "Unknown options_format_version: " << options_format_version;
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return false;
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}
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auto gen = needs_encrypt ? makeGen(options) : neverGen();
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KeyBuffer key;
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if (!read_key(data_rec->metadata_key_dir, gen, &key)) return false;
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std::string crypto_blkdev;
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uint64_t nr_sec;
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if (!create_crypto_blk_dev(kDmNameUserdata, blk_device, key, options, &crypto_blkdev, &nr_sec))
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return false;
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// FIXME handle the corrupt case
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if (needs_encrypt) {
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LOG(INFO) << "Beginning inplace encryption, nr_sec: " << nr_sec;
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off64_t size_already_done = 0;
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auto rc = cryptfs_enable_inplace(crypto_blkdev.data(), blk_device.data(), nr_sec,
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&size_already_done, nr_sec, 0, false);
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if (rc != 0) {
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LOG(ERROR) << "Inplace crypto failed with code: " << rc;
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return false;
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}
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if (static_cast<uint64_t>(size_already_done) != nr_sec) {
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LOG(ERROR) << "Inplace crypto only got up to sector: " << size_already_done;
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return false;
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}
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LOG(INFO) << "Inplace encryption complete";
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}
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LOG(DEBUG) << "Mounting metadata-encrypted filesystem:" << mount_point;
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mount_via_fs_mgr(mount_point.c_str(), crypto_blkdev.c_str());
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return true;
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}
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static bool get_volume_options(CryptoOptions* options) {
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return parse_options(android::base::GetProperty("ro.crypto.volume.metadata.encryption", ""),
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options);
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}
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bool defaultkey_volume_keygen(KeyGeneration* gen) {
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CryptoOptions options;
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if (!get_volume_options(&options)) return false;
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*gen = makeGen(options);
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return true;
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}
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bool defaultkey_setup_ext_volume(const std::string& label, const std::string& blk_device,
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const KeyBuffer& key, std::string* out_crypto_blkdev) {
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LOG(DEBUG) << "defaultkey_setup_ext_volume: " << label << " " << blk_device;
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CryptoOptions options;
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if (!get_volume_options(&options)) return false;
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uint64_t nr_sec;
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return create_crypto_blk_dev(label, blk_device, key, options, out_crypto_blkdev, &nr_sec);
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}
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} // namespace vold
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} // namespace android
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