1/* Sign a module file using the given key.
2 *
3 * Copyright © 2014-2016 Red Hat, Inc. All Rights Reserved.
4 * Copyright © 2015 Intel Corporation.
5 * Copyright © 2016 Hewlett Packard Enterprise Development LP
6 *
7 * Authors: David Howells <dhowells@redhat.com>
8 * David Woodhouse <dwmw2@infradead.org>
9 * Juerg Haefliger <juerg.haefliger@hpe.com>
10 *
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU Lesser General Public License
13 * as published by the Free Software Foundation; either version 2.1
14 * of the licence, or (at your option) any later version.
15 */
16#define _GNU_SOURCE
17#include <stdio.h>
18#include <stdlib.h>
19#include <stdint.h>
20#include <stdbool.h>
21#include <string.h>
22#include <getopt.h>
23#include <err.h>
24#include <arpa/inet.h>
25#include <openssl/opensslv.h>
26#include <openssl/bio.h>
27#include <openssl/evp.h>
28#include <openssl/pem.h>
29#include <openssl/err.h>
30#if OPENSSL_VERSION_MAJOR >= 3
31# define USE_PKCS11_PROVIDER
32# include <openssl/provider.h>
33# include <openssl/store.h>
34#else
35# if !defined(OPENSSL_NO_ENGINE) && !defined(OPENSSL_NO_DEPRECATED_3_0)
36# define USE_PKCS11_ENGINE
37# include <openssl/engine.h>
38# endif
39#endif
40#include "ssl-common.h"
41
42/*
43 * Use CMS if we have openssl-1.0.0 or newer available - otherwise we have to
44 * assume that it's not available and its header file is missing and that we
45 * should use PKCS#7 instead. Switching to the older PKCS#7 format restricts
46 * the options we have on specifying the X.509 certificate we want.
47 *
48 * Further, older versions of OpenSSL don't support manually adding signers to
49 * the PKCS#7 message so have to accept that we get a certificate included in
50 * the signature message. Nor do such older versions of OpenSSL support
51 * signing with anything other than SHA1 - so we're stuck with that if such is
52 * the case.
53 */
54#if defined(LIBRESSL_VERSION_NUMBER) || \
55 OPENSSL_VERSION_NUMBER < 0x10000000L || \
56 defined(OPENSSL_NO_CMS)
57#define USE_PKCS7
58#endif
59#ifndef USE_PKCS7
60#include <openssl/cms.h>
61#else
62#include <openssl/pkcs7.h>
63#endif
64
65struct module_signature {
66 uint8_t algo; /* Public-key crypto algorithm [0] */
67 uint8_t hash; /* Digest algorithm [0] */
68 uint8_t id_type; /* Key identifier type [PKEY_ID_PKCS7] */
69 uint8_t signer_len; /* Length of signer's name [0] */
70 uint8_t key_id_len; /* Length of key identifier [0] */
71 uint8_t __pad[3];
72 uint32_t sig_len; /* Length of signature data */
73};
74
75#define PKEY_ID_PKCS7 2
76
77static char magic_number[] = "~Module signature appended~\n";
78
79static __attribute__((noreturn))
80void format(void)
81{
82 fprintf(stderr,
83 format: "Usage: scripts/sign-file [-dp] <hash algo> <key> <x509> <module> [<dest>]\n");
84 fprintf(stderr,
85 format: " scripts/sign-file -s <raw sig> <hash algo> <x509> <module> [<dest>]\n");
86 exit(status: 2);
87}
88
89static const char *key_pass;
90
91static int pem_pw_cb(char *buf, int len, int w, void *v)
92{
93 int pwlen;
94
95 if (!key_pass)
96 return -1;
97
98 pwlen = strlen(s: key_pass);
99 if (pwlen >= len)
100 return -1;
101
102 strcpy(dest: buf, src: key_pass);
103
104 /* If it's wrong, don't keep trying it. */
105 key_pass = NULL;
106
107 return pwlen;
108}
109
110static EVP_PKEY *read_private_key_pkcs11(const char *private_key_name)
111{
112 EVP_PKEY *private_key = NULL;
113#ifdef USE_PKCS11_PROVIDER
114 OSSL_STORE_CTX *store;
115
116 if (!OSSL_PROVIDER_try_load(NULL, name: "pkcs11", true))
117 ERR(1, "OSSL_PROVIDER_try_load(pkcs11)");
118 if (!OSSL_PROVIDER_try_load(NULL, name: "default", true))
119 ERR(1, "OSSL_PROVIDER_try_load(default)");
120
121 store = OSSL_STORE_open(uri: private_key_name, NULL, NULL, NULL, NULL);
122 ERR(!store, "OSSL_STORE_open");
123
124 while (!OSSL_STORE_eof(ctx: store)) {
125 OSSL_STORE_INFO *info = OSSL_STORE_load(ctx: store);
126
127 if (!info) {
128 drain_openssl_errors(__LINE__, silent: 0);
129 continue;
130 }
131 if (OSSL_STORE_INFO_get_type(info) == OSSL_STORE_INFO_PKEY) {
132 private_key = OSSL_STORE_INFO_get1_PKEY(info);
133 ERR(!private_key, "OSSL_STORE_INFO_get1_PKEY");
134 }
135 OSSL_STORE_INFO_free(info);
136 if (private_key)
137 break;
138 }
139 OSSL_STORE_close(ctx: store);
140#elif defined(USE_PKCS11_ENGINE)
141 ENGINE *e;
142
143 ENGINE_load_builtin_engines();
144 drain_openssl_errors(__LINE__, 1);
145 e = ENGINE_by_id("pkcs11");
146 ERR(!e, "Load PKCS#11 ENGINE");
147 if (ENGINE_init(e))
148 drain_openssl_errors(__LINE__, 1);
149 else
150 ERR(1, "ENGINE_init");
151 if (key_pass)
152 ERR(!ENGINE_ctrl_cmd_string(e, "PIN", key_pass, 0), "Set PKCS#11 PIN");
153 private_key = ENGINE_load_private_key(e, private_key_name, NULL, NULL);
154 ERR(!private_key, "%s", private_key_name);
155#else
156 fprintf(stderr, "no pkcs11 engine/provider available\n");
157 exit(1);
158#endif
159 return private_key;
160}
161
162static EVP_PKEY *read_private_key(const char *private_key_name)
163{
164 if (!strncmp(s1: private_key_name, s2: "pkcs11:", n: 7)) {
165 return read_private_key_pkcs11(private_key_name);
166 } else {
167 EVP_PKEY *private_key;
168 BIO *b;
169
170 b = BIO_new_file(filename: private_key_name, mode: "rb");
171 ERR(!b, "%s", private_key_name);
172 private_key = PEM_read_bio_PrivateKey(out: b, NULL, cb: pem_pw_cb,
173 NULL);
174 ERR(!private_key, "%s", private_key_name);
175 BIO_free(a: b);
176
177 return private_key;
178 }
179}
180
181static X509 *read_x509(const char *x509_name)
182{
183 unsigned char buf[2];
184 X509 *x509;
185 BIO *b;
186 int n;
187
188 b = BIO_new_file(filename: x509_name, mode: "rb");
189 ERR(!b, "%s", x509_name);
190
191 /* Look at the first two bytes of the file to determine the encoding */
192 n = BIO_read(b, data: buf, dlen: 2);
193 if (n != 2) {
194 if (BIO_should_retry(b)) {
195 fprintf(stderr, format: "%s: Read wanted retry\n", x509_name);
196 exit(status: 1);
197 }
198 if (n >= 0) {
199 fprintf(stderr, format: "%s: Short read\n", x509_name);
200 exit(status: 1);
201 }
202 ERR(1, "%s", x509_name);
203 }
204
205 ERR(BIO_reset(b) != 0, "%s", x509_name);
206
207 if (buf[0] == 0x30 && buf[1] >= 0x81 && buf[1] <= 0x84)
208 /* Assume raw DER encoded X.509 */
209 x509 = d2i_X509_bio(bp: b, NULL);
210 else
211 /* Assume PEM encoded X.509 */
212 x509 = PEM_read_bio_X509(out: b, NULL, NULL, NULL);
213
214 BIO_free(a: b);
215 ERR(!x509, "%s", x509_name);
216
217 return x509;
218}
219
220int main(int argc, char **argv)
221{
222 struct module_signature sig_info = { .id_type = PKEY_ID_PKCS7 };
223 char *hash_algo = NULL;
224 char *private_key_name = NULL, *raw_sig_name = NULL;
225 char *x509_name, *module_name, *dest_name;
226 bool save_sig = false, replace_orig;
227 bool sign_only = false;
228 bool raw_sig = false;
229 unsigned char buf[4096];
230 unsigned long module_size, sig_size;
231 unsigned int use_signed_attrs;
232 const EVP_MD *digest_algo;
233 EVP_PKEY *private_key;
234#ifndef USE_PKCS7
235 CMS_ContentInfo *cms = NULL;
236 unsigned int use_keyid = 0;
237#else
238 PKCS7 *pkcs7 = NULL;
239#endif
240 X509 *x509;
241 BIO *bd, *bm;
242 int opt, n;
243 OpenSSL_add_all_algorithms();
244 ERR_load_crypto_strings();
245 ERR_clear_error();
246
247 key_pass = getenv(name: "KBUILD_SIGN_PIN");
248
249#ifndef USE_PKCS7
250 use_signed_attrs = CMS_NOATTR;
251#else
252 use_signed_attrs = PKCS7_NOATTR;
253#endif
254
255 do {
256 opt = getopt(argc: argc, argv: argv, shortopts: "sdpk");
257 switch (opt) {
258 case 's': raw_sig = true; break;
259 case 'p': save_sig = true; break;
260 case 'd': sign_only = true; save_sig = true; break;
261#ifndef USE_PKCS7
262 case 'k': use_keyid = CMS_USE_KEYID; break;
263#endif
264 case -1: break;
265 default: format();
266 }
267 } while (opt != -1);
268
269 argc -= optind;
270 argv += optind;
271 if (argc < 4 || argc > 5)
272 format();
273
274 if (raw_sig) {
275 raw_sig_name = argv[0];
276 hash_algo = argv[1];
277 } else {
278 hash_algo = argv[0];
279 private_key_name = argv[1];
280 }
281 x509_name = argv[2];
282 module_name = argv[3];
283 if (argc == 5 && strcmp(s1: argv[3], s2: argv[4]) != 0) {
284 dest_name = argv[4];
285 replace_orig = false;
286 } else {
287 ERR(asprintf(&dest_name, "%s.~signed~", module_name) < 0,
288 "asprintf");
289 replace_orig = true;
290 }
291
292#ifdef USE_PKCS7
293 if (strcmp(hash_algo, "sha1") != 0) {
294 fprintf(stderr, "sign-file: %s only supports SHA1 signing\n",
295 OPENSSL_VERSION_TEXT);
296 exit(3);
297 }
298#endif
299
300 /* Open the module file */
301 bm = BIO_new_file(filename: module_name, mode: "rb");
302 ERR(!bm, "%s", module_name);
303
304 if (!raw_sig) {
305 /* Read the private key and the X.509 cert the PKCS#7 message
306 * will point to.
307 */
308 private_key = read_private_key(private_key_name);
309 x509 = read_x509(x509_name);
310
311 /* Digest the module data. */
312 OpenSSL_add_all_digests();
313 drain_openssl_errors(__LINE__, silent: 0);
314 digest_algo = EVP_get_digestbyname(name: hash_algo);
315 ERR(!digest_algo, "EVP_get_digestbyname");
316
317#ifndef USE_PKCS7
318 /* Load the signature message from the digest buffer. */
319 cms = CMS_sign(NULL, NULL, NULL, NULL,
320 CMS_NOCERTS | CMS_PARTIAL | CMS_BINARY |
321 CMS_DETACHED | CMS_STREAM);
322 ERR(!cms, "CMS_sign");
323
324 ERR(!CMS_add1_signer(cms, x509, private_key, digest_algo,
325 CMS_NOCERTS | CMS_BINARY |
326 CMS_NOSMIMECAP | use_keyid |
327 use_signed_attrs),
328 "CMS_add1_signer");
329 ERR(CMS_final(cms, bm, NULL, CMS_NOCERTS | CMS_BINARY) != 1,
330 "CMS_final");
331
332#else
333 pkcs7 = PKCS7_sign(x509, private_key, NULL, bm,
334 PKCS7_NOCERTS | PKCS7_BINARY |
335 PKCS7_DETACHED | use_signed_attrs);
336 ERR(!pkcs7, "PKCS7_sign");
337#endif
338
339 if (save_sig) {
340 char *sig_file_name;
341 BIO *b;
342
343 ERR(asprintf(&sig_file_name, "%s.p7s", module_name) < 0,
344 "asprintf");
345 b = BIO_new_file(filename: sig_file_name, mode: "wb");
346 ERR(!b, "%s", sig_file_name);
347#ifndef USE_PKCS7
348 ERR(i2d_CMS_bio_stream(b, cms, NULL, 0) != 1,
349 "%s", sig_file_name);
350#else
351 ERR(i2d_PKCS7_bio(b, pkcs7) != 1,
352 "%s", sig_file_name);
353#endif
354 BIO_free(a: b);
355 }
356
357 if (sign_only) {
358 BIO_free(a: bm);
359 return 0;
360 }
361 }
362
363 /* Open the destination file now so that we can shovel the module data
364 * across as we read it.
365 */
366 bd = BIO_new_file(filename: dest_name, mode: "wb");
367 ERR(!bd, "%s", dest_name);
368
369 /* Append the marker and the PKCS#7 message to the destination file */
370 ERR(BIO_reset(bm) < 0, "%s", module_name);
371 while ((n = BIO_read(b: bm, data: buf, dlen: sizeof(buf))),
372 n > 0) {
373 ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name);
374 }
375 BIO_free(a: bm);
376 ERR(n < 0, "%s", module_name);
377 module_size = BIO_number_written(bio: bd);
378
379 if (!raw_sig) {
380#ifndef USE_PKCS7
381 ERR(i2d_CMS_bio_stream(bd, cms, NULL, 0) != 1, "%s", dest_name);
382#else
383 ERR(i2d_PKCS7_bio(bd, pkcs7) != 1, "%s", dest_name);
384#endif
385 } else {
386 BIO *b;
387
388 /* Read the raw signature file and write the data to the
389 * destination file
390 */
391 b = BIO_new_file(filename: raw_sig_name, mode: "rb");
392 ERR(!b, "%s", raw_sig_name);
393 while ((n = BIO_read(b, data: buf, dlen: sizeof(buf))), n > 0)
394 ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name);
395 BIO_free(a: b);
396 }
397
398 sig_size = BIO_number_written(bio: bd) - module_size;
399 sig_info.sig_len = htonl(sig_size);
400 ERR(BIO_write(bd, &sig_info, sizeof(sig_info)) < 0, "%s", dest_name);
401 ERR(BIO_write(bd, magic_number, sizeof(magic_number) - 1) < 0, "%s", dest_name);
402
403 ERR(BIO_free(bd) != 1, "%s", dest_name);
404
405 /* Finally, if we're signing in place, replace the original. */
406 if (replace_orig)
407 ERR(rename(dest_name, module_name) < 0, "%s", dest_name);
408
409 return 0;
410}
411

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source code of linux/scripts/sign-file.c