platform_system_security/fsverity_init/fsverity_init.cpp
Alan Stokes 246a7f13ac Improved error checking for fsverity_init/odsign.
When attempting to load a non-existent cert I got:
  06-10 12:48:11.939   662   662 E fsverity_init: Failed to add key: Invalid argument
  06-10 12:48:11.940   662   662 E fsverity_init: Failed to load key from stdin
  06-10 12:48:11.941   648   648 I odsign  : Added CompOs key to fs-verity keyring
Which looks like everything worked when nothing did.

Added more error checks on both sides.

Test: Presubmits
Test: Manual
Change-Id: Ib2b17ce75e58dafb0ad6905106e35b11b55e91d0
2021-06-11 10:01:33 +01:00

127 lines
4.2 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.
*/
#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;
}
bool LoadKeyFromStdin(key_serial_t keyring_id, const char* keyname) {
std::string content;
if (!android::base::ReadFdToString(STDIN_FILENO, &content)) {
LOG(ERROR) << "Failed to read key from stdin";
return false;
}
if (!LoadKeyToKeyring(keyring_id, keyname, content.c_str(), content.size())) {
LOG(ERROR) << "Failed to load key from stdin";
return false;
}
return true;
}
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 (!LoadKeyToKeyring(keyring_id, keyname, content.c_str(), content.size())) {
LOG(ERROR) << "Failed to load 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 (argc < 2) {
LOG(ERROR) << "Not enough arguments";
return -1;
}
key_serial_t keyring_id = android::GetKeyringId(".fs-verity");
if (keyring_id < 0) {
LOG(ERROR) << "Failed to find .fs-verity keyring id";
return -1;
}
const std::string_view command = argv[1];
if (command == "--load-verified-keys") {
LoadKeyFromVerifiedPartitions(keyring_id);
} else if (command == "--load-extra-key") {
if (argc != 3) {
LOG(ERROR) << "--load-extra-key requires <key_name> argument.";
return -1;
}
if (!LoadKeyFromStdin(keyring_id, argv[2])) {
return -1;
}
} else if (command == "--lock") {
// 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";
}
if (!android::base::GetBoolProperty("ro.debuggable", false)) {
if (keyctl_restrict_keyring(keyring_id, nullptr, nullptr) < 0) {
PLOG(ERROR) << "Cannot restrict .fs-verity keyring";
}
}
} else {
LOG(ERROR) << "Unknown argument(s).";
return -1;
}
return 0;
}