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95 lines
3.2 KiB
95 lines
3.2 KiB
/*
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* Copyright (C) 2020 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 "VolumeEncryption.h"
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#include <string>
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#include <android-base/logging.h>
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#include <android-base/properties.h>
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#include "KeyBuffer.h"
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#include "KeyUtil.h"
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#include "MetadataCrypt.h"
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#include "cryptfs.h"
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namespace android {
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namespace vold {
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enum class VolumeMethod { kFailed, kCrypt, kDefaultKey };
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static VolumeMethod lookup_volume_method() {
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constexpr uint64_t pre_gki_level = 29;
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auto first_api_level =
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android::base::GetUintProperty<uint64_t>("ro.product.first_api_level", 0);
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auto method = android::base::GetProperty("ro.crypto.volume.metadata.method", "default");
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if (method == "default") {
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return first_api_level > pre_gki_level ? VolumeMethod::kDefaultKey : VolumeMethod::kCrypt;
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} else if (method == "dm-default-key") {
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return VolumeMethod::kDefaultKey;
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} else if (method == "dm-crypt") {
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if (first_api_level > pre_gki_level) {
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LOG(ERROR) << "volume encryption method dm-crypt cannot be used, "
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"ro.product.first_api_level = "
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<< first_api_level;
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return VolumeMethod::kFailed;
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}
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return VolumeMethod::kCrypt;
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} else {
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LOG(ERROR) << "Unknown volume encryption method: " << method;
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return VolumeMethod::kFailed;
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}
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}
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static VolumeMethod volume_method() {
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static VolumeMethod method = lookup_volume_method();
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return method;
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}
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bool generate_volume_key(android::vold::KeyBuffer* key) {
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KeyGeneration gen;
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switch (volume_method()) {
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case VolumeMethod::kFailed:
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LOG(ERROR) << "Volume encryption setup failed";
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return false;
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case VolumeMethod::kCrypt:
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gen = cryptfs_get_keygen();
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break;
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case VolumeMethod::kDefaultKey:
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if (!defaultkey_volume_keygen(&gen)) return false;
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break;
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}
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if (!generateStorageKey(gen, key)) return false;
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return true;
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}
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bool setup_ext_volume(const std::string& label, const std::string& blk_device,
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const android::vold::KeyBuffer& key, std::string* out_crypto_blkdev) {
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switch (volume_method()) {
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case VolumeMethod::kFailed:
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LOG(ERROR) << "Volume encryption setup failed";
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return false;
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case VolumeMethod::kCrypt:
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return cryptfs_setup_ext_volume(label.c_str(), blk_device.c_str(), key,
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out_crypto_blkdev) == 0;
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case VolumeMethod::kDefaultKey:
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return defaultkey_setup_ext_volume(label, blk_device, key, out_crypto_blkdev);
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}
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}
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} // namespace vold
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} // namespace android
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