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/*
* Copyright (C) 2019 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "fs_avb/fs_avb_util.h"
#include <memory>
#include <string>
#include <vector>
#include <android-base/strings.h>
#include <fstab/fstab.h>
#include <libavb/libavb.h>
#include <libdm/dm.h>
#include "avb_util.h"
#include "util.h"
namespace android {
namespace fs_mgr {
// Given a FstabEntry, loads and verifies the vbmeta, to extract the Avb Hashtree descriptor.
std::unique_ptr<VBMetaData> LoadAndVerifyVbmeta(const FstabEntry& fstab_entry,
const std::string& expected_public_key_blob,
std::string* out_public_key_data,
std::string* out_avb_partition_name,
VBMetaVerifyResult* out_verify_result) {
// Derives partition_name from blk_device to query the corresponding AVB HASHTREE descriptor
// to setup dm-verity. The partition_names in AVB descriptors are without A/B suffix.
std::string avb_partition_name = DeriveAvbPartitionName(fstab_entry, fs_mgr_get_slot_suffix(),
fs_mgr_get_other_slot_suffix());
if (out_avb_partition_name) {
*out_avb_partition_name = avb_partition_name;
}
// Updates fstab_entry->blk_device from <partition> to /dev/block/dm-<N> if
// it's a logical partition.
std::string device_path = fstab_entry.blk_device;
if (fstab_entry.fs_mgr_flags.logical &&
!android::base::StartsWith(fstab_entry.blk_device, "/")) {
dm::DeviceMapper& dm = dm::DeviceMapper::Instance();
if (!dm.GetDmDevicePathByName(fstab_entry.blk_device, &device_path)) {
LERROR << "Failed to resolve logical device path for: " << fstab_entry.blk_device;
return nullptr;
}
}
return LoadAndVerifyVbmetaByPath(device_path, avb_partition_name, expected_public_key_blob,
true /* allow_verification_error */,
false /* rollback_protection */, false /* is_chained_vbmeta */,
out_public_key_data, nullptr /* out_verification_disabled */,
out_verify_result);
}
// Given a path, loads and verifies the vbmeta, to extract the Avb Hashtree descriptor.
std::unique_ptr<FsAvbHashtreeDescriptor> GetHashtreeDescriptor(
const std::string& avb_partition_name, VBMetaData&& vbmeta) {
if (!vbmeta.size()) return nullptr;
std::vector<VBMetaData> vbmeta_images;
vbmeta_images.emplace_back(std::move(vbmeta));
return GetHashtreeDescriptor(avb_partition_name, vbmeta_images);
}
} // namespace fs_mgr
} // namespace android
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