1 /*
2 * Copyright (C) 2016 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 #include <errno.h>
18 #include <stdio.h>
19 #include <stdlib.h>
20
21 #include <memory>
22 #include <string>
23
24 #include <android-base/file.h>
25 #include <android-base/unique_fd.h>
26 #include <crypto_utils/android_pubkey.h>
27 #include <fec/io.h>
28 #include <openssl/obj_mac.h>
29 #include <openssl/rsa.h>
30 #include <openssl/sha.h>
31 #include <sparse/sparse.h>
32
load_key(const char * path)33 static RSA* load_key(const char* path) {
34 std::string content;
35 if (!android::base::ReadFileToString(path, &content) ||
36 content.size() < ANDROID_PUBKEY_ENCODED_SIZE) {
37 fprintf(stderr, "Failed to load key from %s\n", path);
38 return nullptr;
39 }
40
41 RSA* key = nullptr;
42 if (!android_pubkey_decode(reinterpret_cast<const uint8_t*>(content.c_str()),
43 ANDROID_PUBKEY_ENCODED_SIZE, &key)) {
44 fprintf(stderr, "Failed to parse key!\n");
45 return nullptr;
46 }
47
48 return key;
49 }
50
verify_table(const char * key_path,const uint8_t * signature,size_t signature_size,const char * table,uint32_t table_length)51 static int verify_table(const char* key_path, const uint8_t* signature, size_t signature_size,
52 const char* table, uint32_t table_length) {
53 // Hash the table
54 uint8_t hash_buf[SHA256_DIGEST_LENGTH];
55 SHA256(const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(table)), table_length, hash_buf);
56
57 // Now get the public key from the keyfile
58 std::unique_ptr<RSA, decltype(&RSA_free)> key(load_key(key_path), RSA_free);
59 if (!key) {
60 fprintf(stderr, "Couldn't load verity keys\n");
61 return -1;
62 }
63
64 // Verify the result
65 if (!RSA_verify(NID_sha256, hash_buf, sizeof(hash_buf), signature, signature_size, key.get())) {
66 fprintf(stderr, "Couldn't verify table\n");
67 return -1;
68 }
69
70 return 0;
71 }
72
main(int argc,char * argv[])73 int main(int argc, char* argv[]) {
74 if (argc != 4 || strcmp(argv[2], "-mincrypt") != 0) {
75 printf("Usage: %s <image> -mincrypt <verity_key>\n"
76 " image the image file (raw or sparse image) to be verified\n"
77 " verity_key the verity key in mincrypt format (/verity_key on device)\n", argv[0]);
78 return 2;
79 }
80
81 // Get the raw image.
82 android::base::unique_fd fd(open(argv[1], O_RDONLY));
83 if (fd == -1) {
84 fprintf(stderr, "failed to open %s: %s\n", argv[1], strerror(errno));
85 return 1;
86 }
87
88 struct sparse_file* file = sparse_file_import_auto(fd, false, false);
89 if (file == nullptr) {
90 fprintf(stderr, "failed to read file %s\n", argv[1]);
91 return 1;
92 }
93
94 TemporaryFile tf;
95 if (sparse_file_write(file, tf.fd, false, false, false) < 0) {
96 fprintf(stderr, "failed to write output file\n");
97 return 1;
98 }
99 sparse_file_destroy(file);
100
101 // Verify.
102 fec::io input(tf.path);
103 if (!input) {
104 return 1;
105 }
106
107 fec_verity_metadata verity;
108 if (!input.get_verity_metadata(verity)) {
109 fprintf(stderr, "failed to get verity metadata\n");
110 return 1;
111 }
112
113 int ret = verify_table(argv[3], verity.signature, sizeof(verity.signature),
114 verity.table, verity.table_length);
115 printf("%s\n", ret == 0 ? "VERIFIED" : "FAILED");
116 return ret;
117 }
118