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1/* Sign a module file using the given key.
2 *
3 * Copyright © 2014-2015 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#include <openssl/engine.h>
31
32/*
33 * Use CMS if we have openssl-1.0.0 or newer available - otherwise we have to
34 * assume that it's not available and its header file is missing and that we
35 * should use PKCS#7 instead. Switching to the older PKCS#7 format restricts
36 * the options we have on specifying the X.509 certificate we want.
37 *
38 * Further, older versions of OpenSSL don't support manually adding signers to
39 * the PKCS#7 message so have to accept that we get a certificate included in
40 * the signature message. Nor do such older versions of OpenSSL support
41 * signing with anything other than SHA1 - so we're stuck with that if such is
42 * the case.
43 */
44#if OPENSSL_VERSION_NUMBER < 0x10000000L || defined(OPENSSL_NO_CMS)
45#define USE_PKCS7
46#endif
47#ifndef USE_PKCS7
48#include <openssl/cms.h>
49#else
50#include <openssl/pkcs7.h>
51#endif
52
53struct module_signature {
54 uint8_t algo; /* Public-key crypto algorithm [0] */
55 uint8_t hash; /* Digest algorithm [0] */
56 uint8_t id_type; /* Key identifier type [PKEY_ID_PKCS7] */
57 uint8_t signer_len; /* Length of signer's name [0] */
58 uint8_t key_id_len; /* Length of key identifier [0] */
59 uint8_t __pad[3];
60 uint32_t sig_len; /* Length of signature data */
61};
62
63#define PKEY_ID_PKCS7 2
64
65static char magic_number[] = "~Module signature appended~\n";
66
67static __attribute__((noreturn))
68void format(void)
69{
70 fprintf(stderr,
71 "Usage: scripts/sign-file [-dp] <hash algo> <key> <x509> <module> [<dest>]\n");
72 fprintf(stderr,
73 " scripts/sign-file -s <raw sig> <hash algo> <x509> <module> [<dest>]\n");
74 exit(2);
75}
76
77static void display_openssl_errors(int l)
78{
79 const char *file;
80 char buf[120];
81 int e, line;
82
83 if (ERR_peek_error() == 0)
84 return;
85 fprintf(stderr, "At main.c:%d:\n", l);
86
87 while ((e = ERR_get_error_line(&file, &line))) {
88 ERR_error_string(e, buf);
89 fprintf(stderr, "- SSL %s: %s:%d\n", buf, file, line);
90 }
91}
92
93static void drain_openssl_errors(void)
94{
95 const char *file;
96 int line;
97
98 if (ERR_peek_error() == 0)
99 return;
100 while (ERR_get_error_line(&file, &line)) {}
101}
102
103#define ERR(cond, fmt, ...) \
104 do { \
105 bool __cond = (cond); \
106 display_openssl_errors(__LINE__); \
107 if (__cond) { \
108 err(1, fmt, ## __VA_ARGS__); \
109 } \
110 } while(0)
111
112static const char *key_pass;
113
114static int pem_pw_cb(char *buf, int len, int w, void *v)
115{
116 int pwlen;
117
118 if (!key_pass)
119 return -1;
120
121 pwlen = strlen(key_pass);
122 if (pwlen >= len)
123 return -1;
124
125 strcpy(buf, key_pass);
126
127 /* If it's wrong, don't keep trying it. */
128 key_pass = NULL;
129
130 return pwlen;
131}
132
133static EVP_PKEY *read_private_key(const char *private_key_name)
134{
135 EVP_PKEY *private_key;
136
137 if (!strncmp(private_key_name, "pkcs11:", 7)) {
138 ENGINE *e;
139
140 ENGINE_load_builtin_engines();
141 drain_openssl_errors();
142 e = ENGINE_by_id("pkcs11");
143 ERR(!e, "Load PKCS#11 ENGINE");
144 if (ENGINE_init(e))
145 drain_openssl_errors();
146 else
147 ERR(1, "ENGINE_init");
148 if (key_pass)
149 ERR(!ENGINE_ctrl_cmd_string(e, "PIN", key_pass, 0),
150 "Set PKCS#11 PIN");
151 private_key = ENGINE_load_private_key(e, private_key_name,
152 NULL, NULL);
153 ERR(!private_key, "%s", private_key_name);
154 } else {
155 BIO *b;
156
157 b = BIO_new_file(private_key_name, "rb");
158 ERR(!b, "%s", private_key_name);
159 private_key = PEM_read_bio_PrivateKey(b, NULL, pem_pw_cb,
160 NULL);
161 ERR(!private_key, "%s", private_key_name);
162 BIO_free(b);
163 }
164
165 return private_key;
166}
167
168static X509 *read_x509(const char *x509_name)
169{
170 X509 *x509;
171 BIO *b;
172
173 b = BIO_new_file(x509_name, "rb");
174 ERR(!b, "%s", x509_name);
175 x509 = d2i_X509_bio(b, NULL); /* Binary encoded X.509 */
176 if (!x509) {
177 ERR(BIO_reset(b) != 1, "%s", x509_name);
178 x509 = PEM_read_bio_X509(b, NULL, NULL,
179 NULL); /* PEM encoded X.509 */
180 if (x509)
181 drain_openssl_errors();
182 }
183 BIO_free(b);
184 ERR(!x509, "%s", x509_name);
185
186 return x509;
187}
188
189int main(int argc, char **argv)
190{
191 struct module_signature sig_info = { .id_type = PKEY_ID_PKCS7 };
192 char *hash_algo = NULL;
193 char *private_key_name = NULL, *raw_sig_name = NULL;
194 char *x509_name, *module_name, *dest_name;
195 bool save_sig = false, replace_orig;
196 bool sign_only = false;
197 bool raw_sig = false;
198 unsigned char buf[4096];
199 unsigned long module_size, sig_size;
200 unsigned int use_signed_attrs;
201 const EVP_MD *digest_algo;
202 EVP_PKEY *private_key;
203#ifndef USE_PKCS7
204 CMS_ContentInfo *cms = NULL;
205 unsigned int use_keyid = 0;
206#else
207 PKCS7 *pkcs7 = NULL;
208#endif
209 X509 *x509;
210 BIO *bd, *bm;
211 int opt, n;
212 OpenSSL_add_all_algorithms();
213 ERR_load_crypto_strings();
214 ERR_clear_error();
215
216 key_pass = getenv("KBUILD_SIGN_PIN");
217
218#ifndef USE_PKCS7
219 use_signed_attrs = CMS_NOATTR;
220#else
221 use_signed_attrs = PKCS7_NOATTR;
222#endif
223
224 do {
225 opt = getopt(argc, argv, "sdpk");
226 switch (opt) {
227 case 's': raw_sig = true; break;
228 case 'p': save_sig = true; break;
229 case 'd': sign_only = true; save_sig = true; break;
230#ifndef USE_PKCS7
231 case 'k': use_keyid = CMS_USE_KEYID; break;
232#endif
233 case -1: break;
234 default: format();
235 }
236 } while (opt != -1);
237
238 argc -= optind;
239 argv += optind;
240 if (argc < 4 || argc > 5)
241 format();
242
243 if (raw_sig) {
244 raw_sig_name = argv[0];
245 hash_algo = argv[1];
246 } else {
247 hash_algo = argv[0];
248 private_key_name = argv[1];
249 }
250 x509_name = argv[2];
251 module_name = argv[3];
252 if (argc == 5) {
253 dest_name = argv[4];
254 replace_orig = false;
255 } else {
256 ERR(asprintf(&dest_name, "%s.~signed~", module_name) < 0,
257 "asprintf");
258 replace_orig = true;
259 }
260
261#ifdef USE_PKCS7
262 if (strcmp(hash_algo, "sha1") != 0) {
263 fprintf(stderr, "sign-file: %s only supports SHA1 signing\n",
264 OPENSSL_VERSION_TEXT);
265 exit(3);
266 }
267#endif
268
269 /* Open the module file */
270 bm = BIO_new_file(module_name, "rb");
271 ERR(!bm, "%s", module_name);
272
273 if (!raw_sig) {
274 /* Read the private key and the X.509 cert the PKCS#7 message
275 * will point to.
276 */
277 private_key = read_private_key(private_key_name);
278 x509 = read_x509(x509_name);
279
280 /* Digest the module data. */
281 OpenSSL_add_all_digests();
282 display_openssl_errors(__LINE__);
283 digest_algo = EVP_get_digestbyname(hash_algo);
284 ERR(!digest_algo, "EVP_get_digestbyname");
285
286#ifndef USE_PKCS7
287 /* Load the signature message from the digest buffer. */
288 cms = CMS_sign(NULL, NULL, NULL, NULL,
289 CMS_NOCERTS | CMS_PARTIAL | CMS_BINARY |
290 CMS_DETACHED | CMS_STREAM);
291 ERR(!cms, "CMS_sign");
292
293 ERR(!CMS_add1_signer(cms, x509, private_key, digest_algo,
294 CMS_NOCERTS | CMS_BINARY |
295 CMS_NOSMIMECAP | use_keyid |
296 use_signed_attrs),
297 "CMS_add1_signer");
298 ERR(CMS_final(cms, bm, NULL, CMS_NOCERTS | CMS_BINARY) < 0,
299 "CMS_final");
300
301#else
302 pkcs7 = PKCS7_sign(x509, private_key, NULL, bm,
303 PKCS7_NOCERTS | PKCS7_BINARY |
304 PKCS7_DETACHED | use_signed_attrs);
305 ERR(!pkcs7, "PKCS7_sign");
306#endif
307
308 if (save_sig) {
309 char *sig_file_name;
310 BIO *b;
311
312 ERR(asprintf(&sig_file_name, "%s.p7s", module_name) < 0,
313 "asprintf");
314 b = BIO_new_file(sig_file_name, "wb");
315 ERR(!b, "%s", sig_file_name);
316#ifndef USE_PKCS7
317 ERR(i2d_CMS_bio_stream(b, cms, NULL, 0) < 0,
318 "%s", sig_file_name);
319#else
320 ERR(i2d_PKCS7_bio(b, pkcs7) < 0,
321 "%s", sig_file_name);
322#endif
323 BIO_free(b);
324 }
325
326 if (sign_only) {
327 BIO_free(bm);
328 return 0;
329 }
330 }
331
332 /* Open the destination file now so that we can shovel the module data
333 * across as we read it.
334 */
335 bd = BIO_new_file(dest_name, "wb");
336 ERR(!bd, "%s", dest_name);
337
338 /* Append the marker and the PKCS#7 message to the destination file */
339 ERR(BIO_reset(bm) < 0, "%s", module_name);
340 while ((n = BIO_read(bm, buf, sizeof(buf))),
341 n > 0) {
342 ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name);
343 }
344 BIO_free(bm);
345 ERR(n < 0, "%s", module_name);
346 module_size = BIO_number_written(bd);
347
348 if (!raw_sig) {
349#ifndef USE_PKCS7
350 ERR(i2d_CMS_bio_stream(bd, cms, NULL, 0) < 0, "%s", dest_name);
351#else
352 ERR(i2d_PKCS7_bio(bd, pkcs7) < 0, "%s", dest_name);
353#endif
354 } else {
355 BIO *b;
356
357 /* Read the raw signature file and write the data to the
358 * destination file
359 */
360 b = BIO_new_file(raw_sig_name, "rb");
361 ERR(!b, "%s", raw_sig_name);
362 while ((n = BIO_read(b, buf, sizeof(buf))), n > 0)
363 ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name);
364 BIO_free(b);
365 }
366
367 sig_size = BIO_number_written(bd) - module_size;
368 sig_info.sig_len = htonl(sig_size);
369 ERR(BIO_write(bd, &sig_info, sizeof(sig_info)) < 0, "%s", dest_name);
370 ERR(BIO_write(bd, magic_number, sizeof(magic_number) - 1) < 0, "%s", dest_name);
371
372 ERR(BIO_free(bd) < 0, "%s", dest_name);
373
374 /* Finally, if we're signing in place, replace the original. */
375 if (replace_orig)
376 ERR(rename(dest_name, module_name) < 0, "%s", dest_name);
377
378 return 0;
379}