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))
format(void)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
display_openssl_errors(int l)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 #ifndef OPENSSL_NO_ENGINE
drain_openssl_errors(void)103 static void drain_openssl_errors(void)
104 {
105 const char *file;
106 int line;
107
108 if (ERR_peek_error() == 0)
109 return;
110 while (ERR_get_error_line(&file, &line)) {}
111 }
112 #endif
113
114 #define ERR(cond, fmt, ...) \
115 do { \
116 bool __cond = (cond); \
117 display_openssl_errors(__LINE__); \
118 if (__cond) { \
119 err(1, fmt, ## __VA_ARGS__); \
120 } \
121 } while(0)
122
123 static const char *key_pass;
124
pem_pw_cb(char * buf,int len,int w,void * v)125 static int pem_pw_cb(char *buf, int len, int w, void *v)
126 {
127 int pwlen;
128
129 if (!key_pass)
130 return -1;
131
132 pwlen = strlen(key_pass);
133 if (pwlen >= len)
134 return -1;
135
136 strcpy(buf, key_pass);
137
138 /* If it's wrong, don't keep trying it. */
139 key_pass = NULL;
140
141 return pwlen;
142 }
143
read_private_key(const char * private_key_name)144 static EVP_PKEY *read_private_key(const char *private_key_name)
145 {
146 EVP_PKEY *private_key;
147 BIO *b;
148
149 #ifndef OPENSSL_NO_ENGINE
150 if (!strncmp(private_key_name, "pkcs11:", 7)) {
151 ENGINE *e;
152
153 ENGINE_load_builtin_engines();
154 drain_openssl_errors();
155 e = ENGINE_by_id("pkcs11");
156 ERR(!e, "Load PKCS#11 ENGINE");
157 if (ENGINE_init(e))
158 drain_openssl_errors();
159 else
160 ERR(1, "ENGINE_init");
161 if (key_pass)
162 ERR(!ENGINE_ctrl_cmd_string(e, "PIN", key_pass, 0),
163 "Set PKCS#11 PIN");
164 private_key = ENGINE_load_private_key(e, private_key_name,
165 NULL, NULL);
166 ERR(!private_key, "%s", private_key_name);
167 return private_key;
168 }
169 #endif
170
171 b = BIO_new_file(private_key_name, "rb");
172 ERR(!b, "%s", private_key_name);
173 private_key = PEM_read_bio_PrivateKey(b, NULL, pem_pw_cb,
174 NULL);
175 ERR(!private_key, "%s", private_key_name);
176 BIO_free(b);
177 return private_key;
178 }
179
read_x509(const char * x509_name)180 static X509 *read_x509(const char *x509_name)
181 {
182 unsigned char buf[2];
183 X509 *x509;
184 BIO *b;
185 int n;
186
187 b = BIO_new_file(x509_name, "rb");
188 ERR(!b, "%s", x509_name);
189
190 /* Look at the first two bytes of the file to determine the encoding */
191 n = BIO_read(b, buf, 2);
192 if (n != 2) {
193 if (BIO_should_retry(b)) {
194 fprintf(stderr, "%s: Read wanted retry\n", x509_name);
195 exit(1);
196 }
197 if (n >= 0) {
198 fprintf(stderr, "%s: Short read\n", x509_name);
199 exit(1);
200 }
201 ERR(1, "%s", x509_name);
202 }
203
204 ERR(BIO_reset(b) != 0, "%s", x509_name);
205
206 if (buf[0] == 0x30 && buf[1] >= 0x81 && buf[1] <= 0x84)
207 /* Assume raw DER encoded X.509 */
208 x509 = d2i_X509_bio(b, NULL);
209 else
210 /* Assume PEM encoded X.509 */
211 x509 = PEM_read_bio_X509(b, NULL, NULL, NULL);
212
213 BIO_free(b);
214 ERR(!x509, "%s", x509_name);
215
216 return x509;
217 }
218
main(int argc,char ** argv)219 int main(int argc, char **argv)
220 {
221 struct module_signature sig_info = { .id_type = PKEY_ID_PKCS7 };
222 char *hash_algo = NULL;
223 char *private_key_name = NULL, *raw_sig_name = NULL;
224 char *x509_name, *module_name, *dest_name;
225 bool save_sig = false, replace_orig;
226 bool sign_only = false;
227 bool raw_sig = false;
228 unsigned char buf[4096];
229 unsigned long module_size, sig_size;
230 unsigned int use_signed_attrs;
231 const EVP_MD *digest_algo;
232 EVP_PKEY *private_key;
233 #ifndef USE_PKCS7
234 CMS_ContentInfo *cms = NULL;
235 unsigned int use_keyid = 0;
236 #else
237 PKCS7 *pkcs7 = NULL;
238 #endif
239 X509 *x509;
240 BIO *bd, *bm;
241 int opt, n;
242 OpenSSL_add_all_algorithms();
243 ERR_load_crypto_strings();
244 ERR_clear_error();
245
246 key_pass = getenv("KBUILD_SIGN_PIN");
247
248 #ifndef USE_PKCS7
249 use_signed_attrs = CMS_NOATTR;
250 #else
251 use_signed_attrs = PKCS7_NOATTR;
252 #endif
253
254 do {
255 opt = getopt(argc, argv, "sdpk");
256 switch (opt) {
257 case 's': raw_sig = true; break;
258 case 'p': save_sig = true; break;
259 case 'd': sign_only = true; save_sig = true; break;
260 #ifndef USE_PKCS7
261 case 'k': use_keyid = CMS_USE_KEYID; break;
262 #endif
263 case -1: break;
264 default: format();
265 }
266 } while (opt != -1);
267
268 argc -= optind;
269 argv += optind;
270 if (argc < 4 || argc > 5)
271 format();
272
273 if (raw_sig) {
274 raw_sig_name = argv[0];
275 hash_algo = argv[1];
276 } else {
277 hash_algo = argv[0];
278 private_key_name = argv[1];
279 }
280 x509_name = argv[2];
281 module_name = argv[3];
282 if (argc == 5 && strcmp(argv[3], argv[4]) != 0) {
283 dest_name = argv[4];
284 replace_orig = false;
285 } else {
286 ERR(asprintf(&dest_name, "%s.~signed~", module_name) < 0,
287 "asprintf");
288 replace_orig = true;
289 }
290
291 #ifdef USE_PKCS7
292 if (strcmp(hash_algo, "sha1") != 0) {
293 fprintf(stderr, "sign-file: %s only supports SHA1 signing\n",
294 OPENSSL_VERSION_TEXT);
295 exit(3);
296 }
297 #endif
298
299 /* Open the module file */
300 bm = BIO_new_file(module_name, "rb");
301 ERR(!bm, "%s", module_name);
302
303 if (!raw_sig) {
304 /* Read the private key and the X.509 cert the PKCS#7 message
305 * will point to.
306 */
307 private_key = read_private_key(private_key_name);
308 x509 = read_x509(x509_name);
309
310 /* Digest the module data. */
311 OpenSSL_add_all_digests();
312 display_openssl_errors(__LINE__);
313 digest_algo = EVP_get_digestbyname(hash_algo);
314 ERR(!digest_algo, "EVP_get_digestbyname");
315
316 #ifndef USE_PKCS7
317 /* Load the signature message from the digest buffer. */
318 cms = CMS_sign(NULL, NULL, NULL, NULL,
319 CMS_NOCERTS | CMS_PARTIAL | CMS_BINARY |
320 CMS_DETACHED | CMS_STREAM);
321 ERR(!cms, "CMS_sign");
322
323 ERR(!CMS_add1_signer(cms, x509, private_key, digest_algo,
324 CMS_NOCERTS | CMS_BINARY |
325 CMS_NOSMIMECAP | use_keyid |
326 use_signed_attrs),
327 "CMS_add1_signer");
328 ERR(CMS_final(cms, bm, NULL, CMS_NOCERTS | CMS_BINARY) != 1,
329 "CMS_final");
330
331 #else
332 pkcs7 = PKCS7_sign(x509, private_key, NULL, bm,
333 PKCS7_NOCERTS | PKCS7_BINARY |
334 PKCS7_DETACHED | use_signed_attrs);
335 ERR(!pkcs7, "PKCS7_sign");
336 #endif
337
338 if (save_sig) {
339 char *sig_file_name;
340 BIO *b;
341
342 ERR(asprintf(&sig_file_name, "%s.p7s", module_name) < 0,
343 "asprintf");
344 b = BIO_new_file(sig_file_name, "wb");
345 ERR(!b, "%s", sig_file_name);
346 #ifndef USE_PKCS7
347 ERR(i2d_CMS_bio_stream(b, cms, NULL, 0) != 1,
348 "%s", sig_file_name);
349 #else
350 ERR(i2d_PKCS7_bio(b, pkcs7) != 1,
351 "%s", sig_file_name);
352 #endif
353 BIO_free(b);
354 }
355
356 if (sign_only) {
357 BIO_free(bm);
358 return 0;
359 }
360 }
361
362 /* Open the destination file now so that we can shovel the module data
363 * across as we read it.
364 */
365 bd = BIO_new_file(dest_name, "wb");
366 ERR(!bd, "%s", dest_name);
367
368 /* Append the marker and the PKCS#7 message to the destination file */
369 ERR(BIO_reset(bm) < 0, "%s", module_name);
370 while ((n = BIO_read(bm, buf, sizeof(buf))),
371 n > 0) {
372 ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name);
373 }
374 BIO_free(bm);
375 ERR(n < 0, "%s", module_name);
376 module_size = BIO_number_written(bd);
377
378 if (!raw_sig) {
379 #ifndef USE_PKCS7
380 ERR(i2d_CMS_bio_stream(bd, cms, NULL, 0) != 1, "%s", dest_name);
381 #else
382 ERR(i2d_PKCS7_bio(bd, pkcs7) != 1, "%s", dest_name);
383 #endif
384 } else {
385 BIO *b;
386
387 /* Read the raw signature file and write the data to the
388 * destination file
389 */
390 b = BIO_new_file(raw_sig_name, "rb");
391 ERR(!b, "%s", raw_sig_name);
392 while ((n = BIO_read(b, buf, sizeof(buf))), n > 0)
393 ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name);
394 BIO_free(b);
395 }
396
397 sig_size = BIO_number_written(bd) - module_size;
398 sig_info.sig_len = htonl(sig_size);
399 ERR(BIO_write(bd, &sig_info, sizeof(sig_info)) < 0, "%s", dest_name);
400 ERR(BIO_write(bd, magic_number, sizeof(magic_number) - 1) < 0, "%s", dest_name);
401
402 ERR(BIO_free(bd) != 1, "%s", dest_name);
403
404 /* Finally, if we're signing in place, replace the original. */
405 if (replace_orig)
406 ERR(rename(dest_name, module_name) < 0, "%s", dest_name);
407
408 return 0;
409 }
410