0da66a5537
As early as fsverity_init, the flag can only be static (thus is_fixed_read_only). It is now a constant/false and will be flipped during the ramp up at build time. Bug: 290064770 Test: mma Test: Inspect the generated code Change-Id: I4bd1addb996705f6e6b9f75313bf22b9ecd3e11c
112 lines
4.4 KiB
C++
112 lines
4.4 KiB
C++
/*
|
|
* 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.
|
|
*/
|
|
|
|
//
|
|
// fsverity_init is a tool for loading X.509 certificates into the kernel keyring used by the
|
|
// fsverity builtin signature verification kernel feature
|
|
// (https://www.kernel.org/doc/html/latest/filesystems/fsverity.html#built-in-signature-verification).
|
|
// Starting in Android 14, Android has actually stopped using this feature, as it was too inflexible
|
|
// and caused problems. It has been replaced by userspace signature verification. Also, some uses
|
|
// of fsverity in Android are now for integrity-only use cases.
|
|
//
|
|
// Regardless, there may exist fsverity files on-disk that were created by Android 13 or earlier.
|
|
// These files still have builtin signatures. If the kernel is an older kernel that still has
|
|
// CONFIG_FS_VERITY_BUILTIN_SIGNATURES enabled, these files cannot be opened unless the
|
|
// corresponding key is in the ".fs-verity" keyring. Therefore, this tool still has to exist and be
|
|
// used to load keys into the kernel, even though this has no security purpose anymore.
|
|
//
|
|
// This tool can be removed as soon as all supported kernels are guaranteed to have
|
|
// CONFIG_FS_VERITY_BUILTIN_SIGNATURES disabled, or alternatively as soon as support for upgrades
|
|
// from Android 13 or earlier is no longer required.
|
|
//
|
|
|
|
#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/strings.h>
|
|
#include <android_security_flag.h>
|
|
#include <log/log.h>
|
|
#include <mini_keyctl_utils.h>
|
|
|
|
void LoadKeyFromFile(key_serial_t keyring_id, const char* keyname, const std::string& path) {
|
|
LOG(INFO) << "LoadKeyFromFile path=" << path << " keyname=" << keyname;
|
|
std::string content;
|
|
if (!android::base::ReadFileToString(path, &content)) {
|
|
LOG(ERROR) << "Failed to read key from " << path;
|
|
return;
|
|
}
|
|
if (add_key("asymmetric", keyname, content.c_str(), content.size(), keyring_id) < 0) {
|
|
PLOG(ERROR) << "Failed to add key from " << path;
|
|
}
|
|
}
|
|
|
|
void LoadKeyFromDirectory(key_serial_t keyring_id, const char* keyname_prefix, const char* dir) {
|
|
if (!std::filesystem::exists(dir)) {
|
|
return;
|
|
}
|
|
int counter = 0;
|
|
for (const auto& entry : std::filesystem::directory_iterator(dir)) {
|
|
if (!android::base::EndsWithIgnoreCase(entry.path().c_str(), ".der")) continue;
|
|
std::string keyname = keyname_prefix + std::to_string(counter);
|
|
counter++;
|
|
LoadKeyFromFile(keyring_id, keyname.c_str(), entry.path());
|
|
}
|
|
}
|
|
|
|
void LoadKeyFromVerifiedPartitions(key_serial_t keyring_id) {
|
|
// NB: Directories need to be synced with FileIntegrityService.java in
|
|
// frameworks/base.
|
|
LoadKeyFromDirectory(keyring_id, "fsv_system_", "/system/etc/security/fsverity");
|
|
LoadKeyFromDirectory(keyring_id, "fsv_product_", "/product/etc/security/fsverity");
|
|
}
|
|
|
|
int main(int argc, const char** argv) {
|
|
if (android::security::flag::deprecate_fsverity_init()) {
|
|
// Don't load keys to the built-in fs-verity keyring in kernel. This will make existing
|
|
// files not readable. We expect to only enable the flag when there are no such files or
|
|
// when failure is ok (e.g. with a fallback).
|
|
return 0;
|
|
}
|
|
|
|
if (argc < 2) {
|
|
LOG(ERROR) << "Not enough arguments";
|
|
return -1;
|
|
}
|
|
|
|
key_serial_t keyring_id = android::GetKeyringId(".fs-verity");
|
|
if (keyring_id < 0) {
|
|
// This is expected on newer kernels. See comment at the beginning of this file.
|
|
LOG(DEBUG) << "no initialization required";
|
|
return 0;
|
|
}
|
|
|
|
const std::string_view command = argv[1];
|
|
|
|
if (command == "--load-verified-keys") {
|
|
LoadKeyFromVerifiedPartitions(keyring_id);
|
|
} else {
|
|
LOG(ERROR) << "Unknown argument(s).";
|
|
return -1;
|
|
}
|
|
|
|
return 0;
|
|
}
|