1 /* $NetBSD: pkcs7.c,v 1.5 2021/04/10 19:49:59 nia Exp $ */
2 #if HAVE_CONFIG_H
3 #include "config.h"
4 #endif
5 #include <nbcompat.h>
6 #if HAVE_SYS_CDEFS_H
7 #include <sys/cdefs.h>
8 #endif
9
10 __RCSID("$NetBSD: pkcs7.c,v 1.5 2021/04/10 19:49:59 nia Exp $");
11
12 /*-
13 * Copyright (c) 2004, 2008 The NetBSD Foundation, Inc.
14 * All rights reserved.
15 *
16 * This code is derived from software contributed to The NetBSD Foundation
17 * by Love H�rnquist �strand <lha@it.su.se>
18 *
19 * Redistribution and use in source and binary forms, with or without
20 * modification, are permitted provided that the following conditions
21 * are met:
22 * 1. Redistributions of source code must retain the above copyright
23 * notice, this list of conditions and the following disclaimer.
24 * 2. Redistributions in binary form must reproduce the above copyright
25 * notice, this list of conditions and the following disclaimer in the
26 * documentation and/or other materials provided with the distribution.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
29 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
30 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
31 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
32 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
33 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
34 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
35 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
36 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
37 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
38 * POSSIBILITY OF SUCH DAMAGE.
39 */
40
41 #if HAVE_ERR_H
42 #include <err.h>
43 #endif
44
45 #include <openssl/pkcs7.h>
46 #include <openssl/evp.h>
47 #include <openssl/x509.h>
48 #include <openssl/x509v3.h>
49 #include <openssl/pem.h>
50 #include <openssl/err.h>
51
52 #include "lib.h"
53
54 #ifndef NS_ANY_CA
55 #define NS_ANY_CA (NS_SSL_CA|NS_SMIME_CA|NS_OBJSIGN_CA)
56 #endif
57
58 #if !defined(OPENSSL_VERSION_NUMBER) || (OPENSSL_VERSION_NUMBER < 0x10100000L) || \
59 defined(LIBRESSL_VERSION_NUMBER)
60 #define X509_get_extended_key_usage(x) x->ex_xkusage
61 #define X509_get_extension_flags(x) x->ex_flags
62 #endif
63
64 static const unsigned int pkg_key_usage = XKU_CODE_SIGN | XKU_SMIME;
65
STACK_OF(X509)66 static STACK_OF(X509) *
67 file_to_certs(const char *file)
68 {
69 unsigned long ret;
70 STACK_OF(X509) *certs;
71 FILE *f;
72
73 if ((f = fopen(file, "r")) == NULL) {
74 warn("open failed %s", file);
75 return NULL;
76 }
77
78 certs = sk_X509_new_null();
79 for (;;) {
80 X509 *cert;
81
82 cert = PEM_read_X509(f, NULL, NULL, NULL);
83 if (cert == NULL) {
84 ret = ERR_GET_REASON(ERR_peek_error());
85 if (ret == PEM_R_NO_START_LINE) {
86 /* End of file reached. no error */
87 ERR_clear_error();
88 break;
89 }
90 sk_X509_free(certs);
91 warnx("Can't read certificate in file: %s", file);
92 fclose(f);
93 return NULL;
94 }
95 sk_X509_insert(certs, cert, sk_X509_num(certs));
96 }
97
98 fclose(f);
99
100 if (sk_X509_num(certs) == 0) {
101 sk_X509_free(certs);
102 certs = NULL;
103 warnx("No certificate found in file %s", file);
104 }
105
106 return certs;
107 }
108
109 int
easy_pkcs7_verify(const char * content,size_t len,const char * signature,size_t signature_len,const char * anchor,int is_pkg)110 easy_pkcs7_verify(const char *content, size_t len,
111 const char *signature, size_t signature_len,
112 const char *anchor, int is_pkg)
113 {
114 STACK_OF(X509) *cert_chain, *signers;
115 X509_STORE *store;
116 BIO *sig, *in;
117 PKCS7 *p7;
118 int i, status;
119 X509_NAME *name;
120 char *subject;
121
122 OpenSSL_add_all_algorithms();
123 ERR_load_crypto_strings();
124
125 status = -1;
126
127 if (cert_chain_file)
128 cert_chain = file_to_certs(cert_chain_file);
129 else
130 cert_chain = NULL;
131
132 store = X509_STORE_new();
133 if (store == NULL) {
134 sk_X509_free(cert_chain);
135 warnx("Failed to create certificate store");
136 return -1;
137 }
138
139 X509_STORE_load_locations(store, anchor, NULL);
140
141 in = BIO_new_mem_buf(__UNCONST(content), len);
142 sig = BIO_new_mem_buf(__UNCONST(signature), signature_len);
143 signers = NULL;
144
145 p7 = PEM_read_bio_PKCS7(sig, NULL, NULL, NULL);
146 if (p7 == NULL) {
147 warnx("Failed to parse the signature");
148 goto cleanup;
149 }
150
151 if (PKCS7_verify(p7, cert_chain, store, in, NULL, 0) != 1) {
152 warnx("Failed to verify signature");
153 goto cleanup;
154 }
155
156 signers = PKCS7_get0_signers(p7, NULL, 0);
157 if (signers == NULL) {
158 warnx("Failed to get signers");
159 goto cleanup;
160 }
161
162 if (sk_X509_num(signers) == 0) {
163 warnx("No signers found");
164 goto cleanup;
165 }
166
167 for (i = 0; i < sk_X509_num(signers); i++) {
168 /* Compute ex_xkusage */
169 X509_check_purpose(sk_X509_value(signers, i), -1, -1);
170
171 if (X509_check_ca(sk_X509_value(signers, i))) {
172 warnx("CA keys are not valid for signatures");
173 goto cleanup;
174 }
175 if (is_pkg) {
176 if (X509_get_extended_key_usage(sk_X509_value(signers, i)) != pkg_key_usage) {
177 warnx("Certificate must have CODE SIGNING "
178 "and EMAIL PROTECTION property");
179 goto cleanup;
180 }
181 } else {
182 if (X509_get_extension_flags(sk_X509_value(signers, i)) & EXFLAG_XKUSAGE) {
183 warnx("Certificate must not have any property");
184 goto cleanup;
185 }
186 }
187 }
188
189 printf("Sigature ok, signed by:\n");
190
191 for (i = 0; i < sk_X509_num(signers); i++) {
192 name = X509_get_subject_name(sk_X509_value(signers, i));
193 subject = X509_NAME_oneline(name, NULL, 0);
194
195 printf("\t%s\n", subject);
196
197 OPENSSL_free(subject);
198 }
199
200 status = 0;
201
202 cleanup:
203 sk_X509_free(cert_chain);
204 sk_X509_free(signers);
205 X509_STORE_free(store);
206
207 PKCS7_free(p7);
208 BIO_free(in);
209 BIO_free(sig);
210
211 return status;
212 }
213
214 static int
ssl_pass_cb(char * buf,int size,int rwflag,void * u)215 ssl_pass_cb(char *buf, int size, int rwflag, void *u)
216 {
217
218 if (EVP_read_pw_string(buf, size, "Passphrase :", 0)) {
219 #if OPENSSL_VERSION >= 0x0090608fL
220 OPENSSL_cleanse(buf, size);
221 #else
222 memset(buf, 0, size);
223 #endif
224 return 0;
225 }
226 return strlen(buf);
227 }
228
229 int
easy_pkcs7_sign(const char * content,size_t len,char ** signature,size_t * signature_len,const char * key_file,const char * cert_file)230 easy_pkcs7_sign(const char *content, size_t len,
231 char **signature, size_t *signature_len,
232 const char *key_file, const char *cert_file)
233 {
234 FILE *f;
235 X509 *certificate;
236 STACK_OF(X509) *c, *cert_chain;
237 EVP_PKEY *private_key;
238 char *tmp_sig;
239 BIO *out, *in;
240 PKCS7 *p7;
241 int status;
242
243 OpenSSL_add_all_algorithms();
244 ERR_load_crypto_strings();
245
246 status = -1;
247 private_key = NULL;
248 cert_chain = NULL;
249 in = NULL;
250
251 c = file_to_certs(cert_file);
252
253 if (sk_X509_num(c) != 1) {
254 warnx("More then one certificate in the certificate file");
255 goto cleanup;
256 }
257 certificate = sk_X509_value(c, 0);
258
259 /* Compute ex_kusage */
260 X509_check_purpose(certificate, -1, 0);
261
262 if (X509_check_ca(certificate)) {
263 warnx("CA keys are not valid for signatures");
264 goto cleanup;
265 }
266
267 if (X509_get_extended_key_usage(certificate) != pkg_key_usage) {
268 warnx("Certificate must have CODE SIGNING "
269 "and EMAIL PROTECTION property");
270 goto cleanup;
271 }
272
273 if (cert_chain_file)
274 cert_chain = file_to_certs(cert_chain_file);
275
276 if ((f = fopen(key_file, "r")) == NULL) {
277 warn("Failed to open private key file %s", key_file);
278 goto cleanup;
279 }
280 private_key = PEM_read_PrivateKey(f, NULL, ssl_pass_cb, NULL);
281 fclose(f);
282 if (private_key == NULL) {
283 warnx("Can't read private key: %s", key_file);
284 goto cleanup;
285 }
286
287 if (X509_check_private_key(certificate, private_key) != 1) {
288 warnx("The private key %s doesn't match the certificate %s",
289 key_file, cert_file);
290 goto cleanup;
291 }
292
293 in = BIO_new_mem_buf(__UNCONST(content), len);
294
295 p7 = PKCS7_sign(certificate, private_key, cert_chain, in,
296 PKCS7_DETACHED|PKCS7_NOATTR|PKCS7_BINARY);
297 if (p7 == NULL) {
298 warnx("Failed to create signature structure");
299 goto cleanup;
300 }
301
302 out = BIO_new(BIO_s_mem());
303 PEM_write_bio_PKCS7(out, p7);
304 *signature_len = BIO_get_mem_data(out, &tmp_sig);
305 *signature = xmalloc(*signature_len);
306 memcpy(*signature, tmp_sig, *signature_len);
307 BIO_free_all(out);
308
309 PKCS7_free(p7);
310
311 status = 0;
312
313 cleanup:
314 sk_X509_free(c);
315 sk_X509_free(cert_chain);
316 EVP_PKEY_free(private_key);
317 BIO_free(in);
318
319 return status;
320 }
321