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 | format: "Usage: scripts/sign-file [-dp] <hash algo> <key> <x509> <module> [<dest>]\n" ); |
81 | fprintf(stderr, |
82 | format: " scripts/sign-file -s <raw sig> <hash algo> <x509> <module> [<dest>]\n" ); |
83 | exit(status: 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, format: "At main.c:%d:\n" , l); |
95 | |
96 | while ((e = ERR_get_error_line(file: &file, line: &line))) { |
97 | ERR_error_string(e, buf); |
98 | fprintf(stderr, format: "- 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: &file, line: &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(s: key_pass); |
131 | if (pwlen >= len) |
132 | return -1; |
133 | |
134 | strcpy(dest: buf, src: 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(s1: private_key_name, s2: "pkcs11:" , n: 7)) { |
147 | ENGINE *e; |
148 | |
149 | ENGINE_load_builtin_engines(); |
150 | drain_openssl_errors(); |
151 | e = ENGINE_by_id(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, key_id: 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(filename: private_key_name, mode: "rb" ); |
167 | ERR(!b, "%s" , private_key_name); |
168 | private_key = PEM_read_bio_PrivateKey(out: b, NULL, cb: pem_pw_cb, |
169 | NULL); |
170 | ERR(!private_key, "%s" , private_key_name); |
171 | BIO_free(a: 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(filename: x509_name, mode: "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, data: buf, dlen: 2); |
189 | if (n != 2) { |
190 | if (BIO_should_retry(b)) { |
191 | fprintf(stderr, format: "%s: Read wanted retry\n" , x509_name); |
192 | exit(status: 1); |
193 | } |
194 | if (n >= 0) { |
195 | fprintf(stderr, format: "%s: Short read\n" , x509_name); |
196 | exit(status: 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(bp: b, NULL); |
206 | else |
207 | /* Assume PEM encoded X.509 */ |
208 | x509 = PEM_read_bio_X509(out: b, NULL, NULL, NULL); |
209 | |
210 | BIO_free(a: 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(name: "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: argc, argv: argv, shortopts: "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(s1: argv[3], s2: 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(filename: module_name, mode: "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(name: 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) < 0, |
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(filename: sig_file_name, mode: "wb" ); |
342 | ERR(!b, "%s" , sig_file_name); |
343 | #ifndef USE_PKCS7 |
344 | ERR(i2d_CMS_bio_stream(b, cms, NULL, 0) < 0, |
345 | "%s" , sig_file_name); |
346 | #else |
347 | ERR(i2d_PKCS7_bio(b, pkcs7) < 0, |
348 | "%s" , sig_file_name); |
349 | #endif |
350 | BIO_free(a: b); |
351 | } |
352 | |
353 | if (sign_only) { |
354 | BIO_free(a: 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(filename: dest_name, mode: "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(b: bm, data: buf, dlen: sizeof(buf))), |
368 | n > 0) { |
369 | ERR(BIO_write(bd, buf, n) < 0, "%s" , dest_name); |
370 | } |
371 | BIO_free(a: bm); |
372 | ERR(n < 0, "%s" , module_name); |
373 | module_size = BIO_number_written(bio: bd); |
374 | |
375 | if (!raw_sig) { |
376 | #ifndef USE_PKCS7 |
377 | ERR(i2d_CMS_bio_stream(bd, cms, NULL, 0) < 0, "%s" , dest_name); |
378 | #else |
379 | ERR(i2d_PKCS7_bio(bd, pkcs7) < 0, "%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(filename: raw_sig_name, mode: "rb" ); |
388 | ERR(!b, "%s" , raw_sig_name); |
389 | while ((n = BIO_read(b, data: buf, dlen: sizeof(buf))), n > 0) |
390 | ERR(BIO_write(bd, buf, n) < 0, "%s" , dest_name); |
391 | BIO_free(a: b); |
392 | } |
393 | |
394 | sig_size = BIO_number_written(bio: 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) < 0, "%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 | |