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modsign: Abort modules_install when signing fails
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bc1c373d
DH
1/* Sign a module file using the given key.
2 *
3 * Copyright (C) 2014 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public Licence
8 * as published by the Free Software Foundation; either version
9 * 2 of the Licence, or (at your option) any later version.
10 */
11#define _GNU_SOURCE
12#include <stdio.h>
13#include <stdlib.h>
14#include <stdint.h>
15#include <stdbool.h>
16#include <string.h>
17#include <getopt.h>
18#include <err.h>
19#include <arpa/inet.h>
20#include <openssl/bio.h>
21#include <openssl/evp.h>
22#include <openssl/pem.h>
23#include <openssl/pkcs7.h>
24#include <openssl/err.h>
25
26struct module_signature {
27 uint8_t algo; /* Public-key crypto algorithm [0] */
28 uint8_t hash; /* Digest algorithm [0] */
29 uint8_t id_type; /* Key identifier type [PKEY_ID_PKCS7] */
30 uint8_t signer_len; /* Length of signer's name [0] */
31 uint8_t key_id_len; /* Length of key identifier [0] */
32 uint8_t __pad[3];
33 uint32_t sig_len; /* Length of signature data */
34};
35
36#define PKEY_ID_PKCS7 2
37
38static char magic_number[] = "~Module signature appended~\n";
39
40static __attribute__((noreturn))
41void format(void)
42{
43 fprintf(stderr,
44 "Usage: scripts/sign-file [-dp] <hash algo> <key> <x509> <module> [<dest>]\n");
45 exit(2);
46}
47
48static void display_openssl_errors(int l)
49{
50 const char *file;
51 char buf[120];
52 int e, line;
53
54 if (ERR_peek_error() == 0)
55 return;
56 fprintf(stderr, "At main.c:%d:\n", l);
57
58 while ((e = ERR_get_error_line(&file, &line))) {
59 ERR_error_string(e, buf);
60 fprintf(stderr, "- SSL %s: %s:%d\n", buf, file, line);
61 }
62}
63
64static void drain_openssl_errors(void)
65{
66 const char *file;
67 int line;
68
69 if (ERR_peek_error() == 0)
70 return;
71 while (ERR_get_error_line(&file, &line)) {}
72}
73
74#define ERR(cond, fmt, ...) \
75 do { \
76 bool __cond = (cond); \
77 display_openssl_errors(__LINE__); \
78 if (__cond) { \
79 err(1, fmt, ## __VA_ARGS__); \
80 } \
81 } while(0)
82
83int main(int argc, char **argv)
84{
85 struct module_signature sig_info = { .id_type = PKEY_ID_PKCS7 };
86 char *hash_algo = NULL;
87 char *private_key_name, *x509_name, *module_name, *dest_name;
88 bool save_pkcs7 = false, replace_orig;
23dfbbab 89 bool sign_only = false;
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DH
90 unsigned char buf[4096];
91 unsigned long module_size, pkcs7_size;
92 const EVP_MD *digest_algo;
93 EVP_PKEY *private_key;
94 PKCS7 *pkcs7;
95 X509 *x509;
23dfbbab 96 BIO *b, *bd = NULL, *bm;
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97 int opt, n;
98
99 ERR_load_crypto_strings();
100 ERR_clear_error();
101
102 do {
103 opt = getopt(argc, argv, "dp");
104 switch (opt) {
105 case 'p': save_pkcs7 = true; break;
23dfbbab 106 case 'd': sign_only = true; save_pkcs7 = true; break;
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DH
107 case -1: break;
108 default: format();
109 }
110 } while (opt != -1);
111
112 argc -= optind;
113 argv += optind;
114 if (argc < 4 || argc > 5)
115 format();
116
117 hash_algo = argv[0];
118 private_key_name = argv[1];
119 x509_name = argv[2];
120 module_name = argv[3];
121 if (argc == 5) {
122 dest_name = argv[4];
123 replace_orig = false;
124 } else {
125 ERR(asprintf(&dest_name, "%s.~signed~", module_name) < 0,
126 "asprintf");
127 replace_orig = true;
128 }
129
130 /* Read the private key and the X.509 cert the PKCS#7 message
131 * will point to.
132 */
133 b = BIO_new_file(private_key_name, "rb");
134 ERR(!b, "%s", private_key_name);
135 private_key = PEM_read_bio_PrivateKey(b, NULL, NULL, NULL);
136 BIO_free(b);
137
138 b = BIO_new_file(x509_name, "rb");
139 ERR(!b, "%s", x509_name);
140 x509 = d2i_X509_bio(b, NULL); /* Binary encoded X.509 */
141 if (!x509) {
142 BIO_reset(b);
143 x509 = PEM_read_bio_X509(b, NULL, NULL, NULL); /* PEM encoded X.509 */
144 if (x509)
145 drain_openssl_errors();
146 }
147 BIO_free(b);
148 ERR(!x509, "%s", x509_name);
149
150 /* Open the destination file now so that we can shovel the module data
151 * across as we read it.
152 */
23dfbbab
LR
153 if (!sign_only) {
154 bd = BIO_new_file(dest_name, "wb");
155 ERR(!bd, "%s", dest_name);
156 }
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DH
157
158 /* Digest the module data. */
159 OpenSSL_add_all_digests();
160 display_openssl_errors(__LINE__);
161 digest_algo = EVP_get_digestbyname(hash_algo);
162 ERR(!digest_algo, "EVP_get_digestbyname");
163
164 bm = BIO_new_file(module_name, "rb");
165 ERR(!bm, "%s", module_name);
166
167 /* Load the PKCS#7 message from the digest buffer. */
168 pkcs7 = PKCS7_sign(NULL, NULL, NULL, NULL,
169 PKCS7_NOCERTS | PKCS7_PARTIAL | PKCS7_BINARY | PKCS7_DETACHED | PKCS7_STREAM);
170 ERR(!pkcs7, "PKCS7_sign");
171
172 ERR(!PKCS7_sign_add_signer(pkcs7, x509, private_key, digest_algo, PKCS7_NOCERTS | PKCS7_BINARY),
173 "PKCS7_sign_add_signer");
174 ERR(PKCS7_final(pkcs7, bm, PKCS7_NOCERTS | PKCS7_BINARY) < 0,
175 "PKCS7_final");
176
177 if (save_pkcs7) {
178 char *pkcs7_name;
179
180 ERR(asprintf(&pkcs7_name, "%s.pkcs7", module_name) < 0, "asprintf");
181 b = BIO_new_file(pkcs7_name, "wb");
182 ERR(!b, "%s", pkcs7_name);
183 ERR(i2d_PKCS7_bio_stream(b, pkcs7, NULL, 0) < 0, "%s", pkcs7_name);
184 BIO_free(b);
185 }
186
23dfbbab
LR
187 if (sign_only)
188 return 0;
189
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190 /* Append the marker and the PKCS#7 message to the destination file */
191 ERR(BIO_reset(bm) < 0, "%s", module_name);
192 while ((n = BIO_read(bm, buf, sizeof(buf))),
193 n > 0) {
194 ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name);
195 }
196 ERR(n < 0, "%s", module_name);
197 module_size = BIO_number_written(bd);
198
199 ERR(i2d_PKCS7_bio_stream(bd, pkcs7, NULL, 0) < 0, "%s", dest_name);
200 pkcs7_size = BIO_number_written(bd) - module_size;
201 sig_info.sig_len = htonl(pkcs7_size);
202 ERR(BIO_write(bd, &sig_info, sizeof(sig_info)) < 0, "%s", dest_name);
203 ERR(BIO_write(bd, magic_number, sizeof(magic_number) - 1) < 0, "%s", dest_name);
204
205 ERR(BIO_free(bd) < 0, "%s", dest_name);
206
207 /* Finally, if we're signing in place, replace the original. */
208 if (replace_orig)
209 ERR(rename(dest_name, module_name) < 0, "%s", dest_name);
210
211 return 0;
212}