1 /*
2 * Copyright (C) 2019 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #define LOG_TAG "fsverity_init"
18
19 #include <sys/types.h>
20
21 #include <filesystem>
22 #include <string>
23
24 #include <android-base/file.h>
25 #include <android-base/logging.h>
26 #include <android-base/properties.h>
27 #include <android-base/strings.h>
28 #include <log/log.h>
29 #include <mini_keyctl_utils.h>
30
LoadKeyToKeyring(key_serial_t keyring_id,const char * desc,const char * data,size_t size)31 bool LoadKeyToKeyring(key_serial_t keyring_id, const char* desc, const char* data, size_t size) {
32 key_serial_t key = add_key("asymmetric", desc, data, size, keyring_id);
33 if (key < 0) {
34 PLOG(ERROR) << "Failed to add key";
35 return false;
36 }
37 return true;
38 }
39
LoadKeyFromDirectory(key_serial_t keyring_id,const char * keyname,const char * dir)40 void LoadKeyFromDirectory(key_serial_t keyring_id, const char* keyname, const char* dir) {
41 if (!std::filesystem::exists(dir)) {
42 return;
43 }
44 for (const auto& entry : std::filesystem::directory_iterator(dir)) {
45 if (!android::base::EndsWithIgnoreCase(entry.path().c_str(), ".der")) continue;
46 std::string content;
47 if (!android::base::ReadFileToString(entry.path(), &content)) {
48 continue;
49 }
50 if (!LoadKeyToKeyring(keyring_id, keyname, content.c_str(), content.size())) {
51 LOG(ERROR) << "Failed to load key from " << entry.path();
52 }
53 }
54 }
55
LoadKeyFromVerifiedPartitions(key_serial_t keyring_id)56 void LoadKeyFromVerifiedPartitions(key_serial_t keyring_id) {
57 // NB: Directories need to be synced with FileIntegrityService.java in
58 // frameworks/base.
59 LoadKeyFromDirectory(keyring_id, "fsv_system", "/system/etc/security/fsverity");
60 LoadKeyFromDirectory(keyring_id, "fsv_product", "/product/etc/security/fsverity");
61 }
62
main(int,const char **)63 int main(int /*argc*/, const char** /*argv*/) {
64 key_serial_t keyring_id = android::GetKeyringId(".fs-verity");
65 if (keyring_id < 0) {
66 LOG(ERROR) << "Failed to find .fs-verity keyring id";
67 return -1;
68 }
69
70 // Requires files backed by fs-verity to be verified with a key in .fs-verity
71 // keyring.
72 if (!android::base::WriteStringToFile("1", "/proc/sys/fs/verity/require_signatures")) {
73 PLOG(ERROR) << "Failed to enforce fs-verity signature";
74 }
75
76 LoadKeyFromVerifiedPartitions(keyring_id);
77
78 if (!android::base::GetBoolProperty("ro.debuggable", false)) {
79 if (keyctl_restrict_keyring(keyring_id, nullptr, nullptr) < 0) {
80 PLOG(ERROR) << "Cannot restrict .fs-verity keyring";
81 }
82 }
83 return 0;
84 }
85