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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.
*/
#define LOG_TAG "fsverity_init"
#include <sys/types.h>
#include <filesystem>
#include <string>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/properties.h>
#include <android-base/strings.h>
#include <log/log.h>
#include <mini_keyctl_utils.h>
bool LoadKeyToKeyring(key_serial_t keyring_id, const char* desc, const char* data, size_t size) {
key_serial_t key = add_key("asymmetric", desc, data, size, keyring_id);
if (key < 0) {
PLOG(ERROR) << "Failed to add key";
return false;
}
return true;
}
void LoadKeyFromVerifiedPartitions(key_serial_t keyring_id) {
const char* dir = "/product/etc/security/fsverity";
if (!std::filesystem::exists(dir)) {
LOG(ERROR) << "no such dir: " << dir;
return;
}
for (const auto& entry : std::filesystem::directory_iterator(dir)) {
if (!android::base::EndsWithIgnoreCase(entry.path().c_str(), ".der")) continue;
std::string content;
if (!android::base::ReadFileToString(entry.path(), &content)) {
continue;
}
if (!LoadKeyToKeyring(keyring_id, "fsv_system", content.c_str(), content.size())) {
LOG(ERROR) << "Failed to load key from " << entry.path();
}
}
}
int main(int /*argc*/, const char** /*argv*/) {
key_serial_t keyring_id = android::GetKeyringId(".fs-verity");
if (keyring_id < 0) {
LOG(ERROR) << "Failed to find .fs-verity keyring id";
return -1;
}
// Requires files backed by fs-verity to be verified with a key in .fs-verity
// keyring.
if (!android::base::WriteStringToFile("1", "/proc/sys/fs/verity/require_signatures")) {
PLOG(ERROR) << "Failed to enforce fs-verity signature";
}
LoadKeyFromVerifiedPartitions(keyring_id);
if (!android::base::GetBoolProperty("ro.debuggable", false)) {
if (keyctl_restrict_keyring(keyring_id, nullptr, nullptr) < 0) {
PLOG(ERROR) << "Cannot restrict .fs-verity keyring";
}
}
return 0;
}
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