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 * OpenSSL 3.0 deprecates the OpenSSL's ENGINE API.
34 *
35 * Remove this if/when that API is no longer used
36 */
37 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
38
39 /*
40 * Use CMS if we have openssl-1.0.0 or newer available - otherwise we have to
41 * assume that it's not available and its header file is missing and that we
42 * should use PKCS#7 instead. Switching to the older PKCS#7 format restricts
43 * the options we have on specifying the X.509 certificate we want.
44 *
45 * Further, older versions of OpenSSL don't support manually adding signers to
46 * the PKCS#7 message so have to accept that we get a certificate included in
47 * the signature message. Nor do such older versions of OpenSSL support
48 * signing with anything other than SHA1 - so we're stuck with that if such is
49 * the case.
50 */
51 #if defined(LIBRESSL_VERSION_NUMBER) || \
52 OPENSSL_VERSION_NUMBER < 0x10000000L || \
53 defined(OPENSSL_NO_CMS)
54 #define USE_PKCS7
55 #endif
56 #ifndef USE_PKCS7
57 #include <openssl/cms.h>
58 #else
59 #include <openssl/pkcs7.h>
60 #endif
61
62 struct module_signature {
63 uint8_t algo; /* Public-key crypto algorithm [0] */
64 uint8_t hash; /* Digest algorithm [0] */
65 uint8_t id_type; /* Key identifier type [PKEY_ID_PKCS7] */
66 uint8_t signer_len; /* Length of signer's name [0] */
67 uint8_t key_id_len; /* Length of key identifier [0] */
68 uint8_t __pad[3];
69 uint32_t sig_len; /* Length of signature data */
70 };
71
72 #define PKEY_ID_PKCS7 2
73
74 static char magic_number[] = "~Module signature appended~\n";
75
76 static __attribute__((noreturn))
77 void format(void)
78 {
79 fprintf(stderr,
80 "Usage: scripts/sign-file [-dp] <hash algo> <key> <x509> <module> [<dest>]\n");
81 fprintf(stderr,
82 " scripts/sign-file -s <raw sig> <hash algo> <x509> <module> [<dest>]\n");
83 exit(2);
84 }
85
86 static void display_openssl_errors(int l)
87 {
88 const char *file;
89 char buf[120];
90 int e, line;
91
92 if (ERR_peek_error() == 0)
93 return;
94 fprintf(stderr, "At main.c:%d:\n", l);
95
96 while ((e = ERR_get_error_line(&file, &line))) {
97 ERR_error_string(e, buf);
98 fprintf(stderr, "- SSL %s: %s:%d\n", buf, file, line);
99 }
100 }
101
102 static void drain_openssl_errors(void)
103 {
104 const char *file;
105 int line;
106
107 if (ERR_peek_error() == 0)
108 return;
109 while (ERR_get_error_line(&file, &line)) {}
110 }
111
112 #define ERR(cond, fmt, ...) \
113 do { \
114 bool __cond = (cond); \
115 display_openssl_errors(__LINE__); \
116 if (__cond) { \
117 errx(1, fmt, ## __VA_ARGS__); \
118 } \
119 } while(0)
120
121 static const char *key_pass;
122
123 static int pem_pw_cb(char *buf, int len, int w, void *v)
124 {
125 int pwlen;
126
127 if (!key_pass)
128 return -1;
129
130 pwlen = strlen(key_pass);
131 if (pwlen >= len)
132 return -1;
133
134 strcpy(buf, key_pass);
135
136 /* If it's wrong, don't keep trying it. */
137 key_pass = NULL;
138
139 return pwlen;
140 }
141
142 static EVP_PKEY *read_private_key(const char *private_key_name)
143 {
144 EVP_PKEY *private_key;
145
146 if (!strncmp(private_key_name, "pkcs11:", 7)) {
147 ENGINE *e;
148
149 ENGINE_load_builtin_engines();
150 drain_openssl_errors();
151 e = ENGINE_by_id("pkcs11");
152 ERR(!e, "Load PKCS#11 ENGINE");
153 if (ENGINE_init(e))
154 drain_openssl_errors();
155 else
156 ERR(1, "ENGINE_init");
157 if (key_pass)
158 ERR(!ENGINE_ctrl_cmd_string(e, "PIN", key_pass, 0),
159 "Set PKCS#11 PIN");
160 private_key = ENGINE_load_private_key(e, private_key_name,
161 NULL, NULL);
162 ERR(!private_key, "%s", private_key_name);
163 } else {
164 BIO *b;
165
166 b = BIO_new_file(private_key_name, "rb");
167 ERR(!b, "%s", private_key_name);
168 private_key = PEM_read_bio_PrivateKey(b, NULL, pem_pw_cb,
169 NULL);
170 ERR(!private_key, "%s", private_key_name);
171 BIO_free(b);
172 }
173
174 return private_key;
175 }
176
177 static X509 *read_x509(const char *x509_name)
178 {
179 unsigned char buf[2];
180 X509 *x509;
181 BIO *b;
182 int n;
183
184 b = BIO_new_file(x509_name, "rb");
185 ERR(!b, "%s", x509_name);
186
187 /* Look at the first two bytes of the file to determine the encoding */
188 n = BIO_read(b, buf, 2);
189 if (n != 2) {
190 if (BIO_should_retry(b)) {
191 fprintf(stderr, "%s: Read wanted retry\n", x509_name);
192 exit(1);
193 }
194 if (n >= 0) {
195 fprintf(stderr, "%s: Short read\n", x509_name);
196 exit(1);
197 }
198 ERR(1, "%s", x509_name);
199 }
200
201 ERR(BIO_reset(b) != 0, "%s", x509_name);
202
203 if (buf[0] == 0x30 && buf[1] >= 0x81 && buf[1] <= 0x84)
204 /* Assume raw DER encoded X.509 */
205 x509 = d2i_X509_bio(b, NULL);
206 else
207 /* Assume PEM encoded X.509 */
208 x509 = PEM_read_bio_X509(b, NULL, NULL, NULL);
209
210 BIO_free(b);
211 ERR(!x509, "%s", x509_name);
212
213 return x509;
214 }
215
216 int main(int argc, char **argv)
217 {
218 struct module_signature sig_info = { .id_type = PKEY_ID_PKCS7 };
219 char *hash_algo = NULL;
220 char *private_key_name = NULL, *raw_sig_name = NULL;
221 char *x509_name, *module_name, *dest_name;
222 bool save_sig = false, replace_orig;
223 bool sign_only = false;
224 bool raw_sig = false;
225 unsigned char buf[4096];
226 unsigned long module_size, sig_size;
227 unsigned int use_signed_attrs;
228 const EVP_MD *digest_algo;
229 EVP_PKEY *private_key;
230 #ifndef USE_PKCS7
231 CMS_ContentInfo *cms = NULL;
232 unsigned int use_keyid = 0;
233 #else
234 PKCS7 *pkcs7 = NULL;
235 #endif
236 X509 *x509;
237 BIO *bd, *bm;
238 int opt, n;
239 OpenSSL_add_all_algorithms();
240 ERR_load_crypto_strings();
241 ERR_clear_error();
242
243 key_pass = getenv("KBUILD_SIGN_PIN");
244
245 #ifndef USE_PKCS7
246 use_signed_attrs = CMS_NOATTR;
247 #else
248 use_signed_attrs = PKCS7_NOATTR;
249 #endif
250
251 do {
252 opt = getopt(argc, argv, "sdpk");
253 switch (opt) {
254 case 's': raw_sig = true; break;
255 case 'p': save_sig = true; break;
256 case 'd': sign_only = true; save_sig = true; break;
257 #ifndef USE_PKCS7
258 case 'k': use_keyid = CMS_USE_KEYID; break;
259 #endif
260 case -1: break;
261 default: format();
262 }
263 } while (opt != -1);
264
265 argc -= optind;
266 argv += optind;
267 if (argc < 4 || argc > 5)
268 format();
269
270 if (raw_sig) {
271 raw_sig_name = argv[0];
272 hash_algo = argv[1];
273 } else {
274 hash_algo = argv[0];
275 private_key_name = argv[1];
276 }
277 x509_name = argv[2];
278 module_name = argv[3];
279 if (argc == 5 && strcmp(argv[3], argv[4]) != 0) {
280 dest_name = argv[4];
281 replace_orig = false;
282 } else {
283 ERR(asprintf(&dest_name, "%s.~signed~", module_name) < 0,
284 "asprintf");
285 replace_orig = true;
286 }
287
288 #ifdef USE_PKCS7
289 if (strcmp(hash_algo, "sha1") != 0) {
290 fprintf(stderr, "sign-file: %s only supports SHA1 signing\n",
291 OPENSSL_VERSION_TEXT);
292 exit(3);
293 }
294 #endif
295
296 /* Open the module file */
297 bm = BIO_new_file(module_name, "rb");
298 ERR(!bm, "%s", module_name);
299
300 if (!raw_sig) {
301 /* Read the private key and the X.509 cert the PKCS#7 message
302 * will point to.
303 */
304 private_key = read_private_key(private_key_name);
305 x509 = read_x509(x509_name);
306
307 /* Digest the module data. */
308 OpenSSL_add_all_digests();
309 display_openssl_errors(__LINE__);
310 digest_algo = EVP_get_digestbyname(hash_algo);
311 ERR(!digest_algo, "EVP_get_digestbyname");
312
313 #ifndef USE_PKCS7
314 /* Load the signature message from the digest buffer. */
315 cms = CMS_sign(NULL, NULL, NULL, NULL,
316 CMS_NOCERTS | CMS_PARTIAL | CMS_BINARY |
317 CMS_DETACHED | CMS_STREAM);
318 ERR(!cms, "CMS_sign");
319
320 ERR(!CMS_add1_signer(cms, x509, private_key, digest_algo,
321 CMS_NOCERTS | CMS_BINARY |
322 CMS_NOSMIMECAP | use_keyid |
323 use_signed_attrs),
324 "CMS_add1_signer");
325 ERR(CMS_final(cms, bm, NULL, CMS_NOCERTS | CMS_BINARY) != 1,
326 "CMS_final");
327
328 #else
329 pkcs7 = PKCS7_sign(x509, private_key, NULL, bm,
330 PKCS7_NOCERTS | PKCS7_BINARY |
331 PKCS7_DETACHED | use_signed_attrs);
332 ERR(!pkcs7, "PKCS7_sign");
333 #endif
334
335 if (save_sig) {
336 char *sig_file_name;
337 BIO *b;
338
339 ERR(asprintf(&sig_file_name, "%s.p7s", module_name) < 0,
340 "asprintf");
341 b = BIO_new_file(sig_file_name, "wb");
342 ERR(!b, "%s", sig_file_name);
343 #ifndef USE_PKCS7
344 ERR(i2d_CMS_bio_stream(b, cms, NULL, 0) != 1,
345 "%s", sig_file_name);
346 #else
347 ERR(i2d_PKCS7_bio(b, pkcs7) != 1,
348 "%s", sig_file_name);
349 #endif
350 BIO_free(b);
351 }
352
353 if (sign_only) {
354 BIO_free(bm);
355 return 0;
356 }
357 }
358
359 /* Open the destination file now so that we can shovel the module data
360 * across as we read it.
361 */
362 bd = BIO_new_file(dest_name, "wb");
363 ERR(!bd, "%s", dest_name);
364
365 /* Append the marker and the PKCS#7 message to the destination file */
366 ERR(BIO_reset(bm) < 0, "%s", module_name);
367 while ((n = BIO_read(bm, buf, sizeof(buf))),
368 n > 0) {
369 ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name);
370 }
371 BIO_free(bm);
372 ERR(n < 0, "%s", module_name);
373 module_size = BIO_number_written(bd);
374
375 if (!raw_sig) {
376 #ifndef USE_PKCS7
377 ERR(i2d_CMS_bio_stream(bd, cms, NULL, 0) != 1, "%s", dest_name);
378 #else
379 ERR(i2d_PKCS7_bio(bd, pkcs7) != 1, "%s", dest_name);
380 #endif
381 } else {
382 BIO *b;
383
384 /* Read the raw signature file and write the data to the
385 * destination file
386 */
387 b = BIO_new_file(raw_sig_name, "rb");
388 ERR(!b, "%s", raw_sig_name);
389 while ((n = BIO_read(b, buf, sizeof(buf))), n > 0)
390 ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name);
391 BIO_free(b);
392 }
393
394 sig_size = BIO_number_written(bd) - module_size;
395 sig_info.sig_len = htonl(sig_size);
396 ERR(BIO_write(bd, &sig_info, sizeof(sig_info)) < 0, "%s", dest_name);
397 ERR(BIO_write(bd, magic_number, sizeof(magic_number) - 1) < 0, "%s", dest_name);
398
399 ERR(BIO_free(bd) != 1, "%s", dest_name);
400
401 /* Finally, if we're signing in place, replace the original. */
402 if (replace_orig)
403 ERR(rename(dest_name, module_name) < 0, "%s", dest_name);
404
405 return 0;
406 }
407
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