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 #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 defined(LIBRESSL_VERSION_NUMBER) || \
45 OPENSSL_VERSION_NUMBER < 0x10000000L || \
46 defined(OPENSSL_NO_CMS)
47 #define USE_PKCS7
48 #endif
49 #ifndef USE_PKCS7
50 #include <openssl/cms.h>
51 #else
52 #include <openssl/pkcs7.h>
53 #endif
54
55 struct module_signature {
56 uint8_t algo; /* Public-key crypto algorithm [0] */
57 uint8_t hash; /* Digest algorithm [0] */
58 uint8_t id_type; /* Key identifier type [PKEY_ID_PKCS7] */
59 uint8_t signer_len; /* Length of signer's name [0] */
60 uint8_t key_id_len; /* Length of key identifier [0] */
61 uint8_t __pad[3];
62 uint32_t sig_len; /* Length of signature data */
63 };
64
65 #define PKEY_ID_PKCS7 2
66
67 static char magic_number[] = "~Module signature appended~\n";
68
69 static __attribute__((noreturn))
format(void)70 void format(void)
71 {
72 fprintf(stderr,
73 "Usage: scripts/sign-file [-dp] <hash algo> <key> <x509> <module> [<dest>]\n");
74 fprintf(stderr,
75 " scripts/sign-file -s <raw sig> <hash algo> <x509> <module> [<dest>]\n");
76 exit(2);
77 }
78
display_openssl_errors(int l)79 static void display_openssl_errors(int l)
80 {
81 const char *file;
82 char buf[120];
83 int e, line;
84
85 if (ERR_peek_error() == 0)
86 return;
87 fprintf(stderr, "At main.c:%d:\n", l);
88
89 while ((e = ERR_get_error_line(&file, &line))) {
90 ERR_error_string(e, buf);
91 fprintf(stderr, "- SSL %s: %s:%d\n", buf, file, line);
92 }
93 }
94
drain_openssl_errors(void)95 static void drain_openssl_errors(void)
96 {
97 const char *file;
98 int line;
99
100 if (ERR_peek_error() == 0)
101 return;
102 while (ERR_get_error_line(&file, &line)) {}
103 }
104
105 #define ERR(cond, fmt, ...) \
106 do { \
107 bool __cond = (cond); \
108 display_openssl_errors(__LINE__); \
109 if (__cond) { \
110 err(1, fmt, ## __VA_ARGS__); \
111 } \
112 } while(0)
113
114 static const char *key_pass;
115
pem_pw_cb(char * buf,int len,int w,void * v)116 static int pem_pw_cb(char *buf, int len, int w, void *v)
117 {
118 int pwlen;
119
120 if (!key_pass)
121 return -1;
122
123 pwlen = strlen(key_pass);
124 if (pwlen >= len)
125 return -1;
126
127 strcpy(buf, key_pass);
128
129 /* If it's wrong, don't keep trying it. */
130 key_pass = NULL;
131
132 return pwlen;
133 }
134
read_private_key(const char * private_key_name)135 static EVP_PKEY *read_private_key(const char *private_key_name)
136 {
137 EVP_PKEY *private_key;
138
139 if (!strncmp(private_key_name, "pkcs11:", 7)) {
140 ENGINE *e;
141
142 ENGINE_load_builtin_engines();
143 drain_openssl_errors();
144 e = ENGINE_by_id("pkcs11");
145 ERR(!e, "Load PKCS#11 ENGINE");
146 if (ENGINE_init(e))
147 drain_openssl_errors();
148 else
149 ERR(1, "ENGINE_init");
150 if (key_pass)
151 ERR(!ENGINE_ctrl_cmd_string(e, "PIN", key_pass, 0),
152 "Set PKCS#11 PIN");
153 private_key = ENGINE_load_private_key(e, private_key_name,
154 NULL, NULL);
155 ERR(!private_key, "%s", private_key_name);
156 } else {
157 BIO *b;
158
159 b = BIO_new_file(private_key_name, "rb");
160 ERR(!b, "%s", private_key_name);
161 private_key = PEM_read_bio_PrivateKey(b, NULL, pem_pw_cb,
162 NULL);
163 ERR(!private_key, "%s", private_key_name);
164 BIO_free(b);
165 }
166
167 return private_key;
168 }
169
read_x509(const char * x509_name)170 static X509 *read_x509(const char *x509_name)
171 {
172 unsigned char buf[2];
173 X509 *x509;
174 BIO *b;
175 int n;
176
177 b = BIO_new_file(x509_name, "rb");
178 ERR(!b, "%s", x509_name);
179
180 /* Look at the first two bytes of the file to determine the encoding */
181 n = BIO_read(b, buf, 2);
182 if (n != 2) {
183 if (BIO_should_retry(b)) {
184 fprintf(stderr, "%s: Read wanted retry\n", x509_name);
185 exit(1);
186 }
187 if (n >= 0) {
188 fprintf(stderr, "%s: Short read\n", x509_name);
189 exit(1);
190 }
191 ERR(1, "%s", x509_name);
192 }
193
194 ERR(BIO_reset(b) != 0, "%s", x509_name);
195
196 if (buf[0] == 0x30 && buf[1] >= 0x81 && buf[1] <= 0x84)
197 /* Assume raw DER encoded X.509 */
198 x509 = d2i_X509_bio(b, NULL);
199 else
200 /* Assume PEM encoded X.509 */
201 x509 = PEM_read_bio_X509(b, NULL, NULL, NULL);
202
203 BIO_free(b);
204 ERR(!x509, "%s", x509_name);
205
206 return x509;
207 }
208
main(int argc,char ** argv)209 int main(int argc, char **argv)
210 {
211 struct module_signature sig_info = { .id_type = PKEY_ID_PKCS7 };
212 char *hash_algo = NULL;
213 char *private_key_name = NULL, *raw_sig_name = NULL;
214 char *x509_name, *module_name, *dest_name;
215 bool save_sig = false, replace_orig;
216 bool sign_only = false;
217 bool raw_sig = false;
218 unsigned char buf[4096];
219 unsigned long module_size, sig_size;
220 unsigned int use_signed_attrs;
221 const EVP_MD *digest_algo;
222 EVP_PKEY *private_key;
223 #ifndef USE_PKCS7
224 CMS_ContentInfo *cms = NULL;
225 unsigned int use_keyid = 0;
226 #else
227 PKCS7 *pkcs7 = NULL;
228 #endif
229 X509 *x509;
230 BIO *bd, *bm;
231 int opt, n;
232 OpenSSL_add_all_algorithms();
233 ERR_load_crypto_strings();
234 ERR_clear_error();
235
236 key_pass = getenv("KBUILD_SIGN_PIN");
237
238 #ifndef USE_PKCS7
239 use_signed_attrs = CMS_NOATTR;
240 #else
241 use_signed_attrs = PKCS7_NOATTR;
242 #endif
243
244 do {
245 opt = getopt(argc, argv, "sdpk");
246 switch (opt) {
247 case 's': raw_sig = true; break;
248 case 'p': save_sig = true; break;
249 case 'd': sign_only = true; save_sig = true; break;
250 #ifndef USE_PKCS7
251 case 'k': use_keyid = CMS_USE_KEYID; break;
252 #endif
253 case -1: break;
254 default: format();
255 }
256 } while (opt != -1);
257
258 argc -= optind;
259 argv += optind;
260 if (argc < 4 || argc > 5)
261 format();
262
263 if (raw_sig) {
264 raw_sig_name = argv[0];
265 hash_algo = argv[1];
266 } else {
267 hash_algo = argv[0];
268 private_key_name = argv[1];
269 }
270 x509_name = argv[2];
271 module_name = argv[3];
272 if (argc == 5 && strcmp(argv[3], argv[4]) != 0) {
273 dest_name = argv[4];
274 replace_orig = false;
275 } else {
276 ERR(asprintf(&dest_name, "%s.~signed~", module_name) < 0,
277 "asprintf");
278 replace_orig = true;
279 }
280
281 #ifdef USE_PKCS7
282 if (strcmp(hash_algo, "sha1") != 0) {
283 fprintf(stderr, "sign-file: %s only supports SHA1 signing\n",
284 OPENSSL_VERSION_TEXT);
285 exit(3);
286 }
287 #endif
288
289 /* Open the module file */
290 bm = BIO_new_file(module_name, "rb");
291 ERR(!bm, "%s", module_name);
292
293 if (!raw_sig) {
294 /* Read the private key and the X.509 cert the PKCS#7 message
295 * will point to.
296 */
297 private_key = read_private_key(private_key_name);
298 x509 = read_x509(x509_name);
299
300 /* Digest the module data. */
301 OpenSSL_add_all_digests();
302 display_openssl_errors(__LINE__);
303 digest_algo = EVP_get_digestbyname(hash_algo);
304 ERR(!digest_algo, "EVP_get_digestbyname");
305
306 #ifndef USE_PKCS7
307 /* Load the signature message from the digest buffer. */
308 cms = CMS_sign(NULL, NULL, NULL, NULL,
309 CMS_NOCERTS | CMS_PARTIAL | CMS_BINARY |
310 CMS_DETACHED | CMS_STREAM);
311 ERR(!cms, "CMS_sign");
312
313 ERR(!CMS_add1_signer(cms, x509, private_key, digest_algo,
314 CMS_NOCERTS | CMS_BINARY |
315 CMS_NOSMIMECAP | use_keyid |
316 use_signed_attrs),
317 "CMS_add1_signer");
318 ERR(CMS_final(cms, bm, NULL, CMS_NOCERTS | CMS_BINARY) < 0,
319 "CMS_final");
320
321 #else
322 pkcs7 = PKCS7_sign(x509, private_key, NULL, bm,
323 PKCS7_NOCERTS | PKCS7_BINARY |
324 PKCS7_DETACHED | use_signed_attrs);
325 ERR(!pkcs7, "PKCS7_sign");
326 #endif
327
328 if (save_sig) {
329 char *sig_file_name;
330 BIO *b;
331
332 ERR(asprintf(&sig_file_name, "%s.p7s", module_name) < 0,
333 "asprintf");
334 b = BIO_new_file(sig_file_name, "wb");
335 ERR(!b, "%s", sig_file_name);
336 #ifndef USE_PKCS7
337 ERR(i2d_CMS_bio_stream(b, cms, NULL, 0) < 0,
338 "%s", sig_file_name);
339 #else
340 ERR(i2d_PKCS7_bio(b, pkcs7) < 0,
341 "%s", sig_file_name);
342 #endif
343 BIO_free(b);
344 }
345
346 if (sign_only) {
347 BIO_free(bm);
348 return 0;
349 }
350 }
351
352 /* Open the destination file now so that we can shovel the module data
353 * across as we read it.
354 */
355 bd = BIO_new_file(dest_name, "wb");
356 ERR(!bd, "%s", dest_name);
357
358 /* Append the marker and the PKCS#7 message to the destination file */
359 ERR(BIO_reset(bm) < 0, "%s", module_name);
360 while ((n = BIO_read(bm, buf, sizeof(buf))),
361 n > 0) {
362 ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name);
363 }
364 BIO_free(bm);
365 ERR(n < 0, "%s", module_name);
366 module_size = BIO_number_written(bd);
367
368 if (!raw_sig) {
369 #ifndef USE_PKCS7
370 ERR(i2d_CMS_bio_stream(bd, cms, NULL, 0) < 0, "%s", dest_name);
371 #else
372 ERR(i2d_PKCS7_bio(bd, pkcs7) < 0, "%s", dest_name);
373 #endif
374 } else {
375 BIO *b;
376
377 /* Read the raw signature file and write the data to the
378 * destination file
379 */
380 b = BIO_new_file(raw_sig_name, "rb");
381 ERR(!b, "%s", raw_sig_name);
382 while ((n = BIO_read(b, buf, sizeof(buf))), n > 0)
383 ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name);
384 BIO_free(b);
385 }
386
387 sig_size = BIO_number_written(bd) - module_size;
388 sig_info.sig_len = htonl(sig_size);
389 ERR(BIO_write(bd, &sig_info, sizeof(sig_info)) < 0, "%s", dest_name);
390 ERR(BIO_write(bd, magic_number, sizeof(magic_number) - 1) < 0, "%s", dest_name);
391
392 ERR(BIO_free(bd) < 0, "%s", dest_name);
393
394 /* Finally, if we're signing in place, replace the original. */
395 if (replace_orig)
396 ERR(rename(dest_name, module_name) < 0, "%s", dest_name);
397
398 return 0;
399 }
400