xref: /netbsd-src/external/bsd/pkg_install/dist/lib/pkcs7.c (revision c38e7cc395b1472a774ff828e46123de44c628e9)
1 /*	$NetBSD: pkcs7.c,v 1.3 2018/02/04 09:00:51 maya 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 1.3 2018/02/04 09:00:51 maya 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 #define X509_get_extended_key_usage(x) x->ex_xkusage
60 #define X509_get_extension_flags(x) x->ex_flags
61 #endif
62 
63 static const unsigned int pkg_key_usage = XKU_CODE_SIGN | XKU_SMIME;
64 
65 static STACK_OF(X509) *
66 file_to_certs(const char *file)
67 {
68 	unsigned long ret;
69 	STACK_OF(X509) *certs;
70 	FILE *f;
71 
72 	if ((f = fopen(file, "r")) == NULL) {
73 		warn("open failed %s", file);
74 		return NULL;
75 	}
76 
77 	certs = sk_X509_new_null();
78 	for (;;) {
79 		X509 *cert;
80 
81 		cert = PEM_read_X509(f, NULL, NULL, NULL);
82 		if (cert == NULL) {
83 			ret = ERR_GET_REASON(ERR_peek_error());
84 			if (ret == PEM_R_NO_START_LINE) {
85 				/* End of file reached. no error */
86 				ERR_clear_error();
87 				break;
88 			}
89 			sk_X509_free(certs);
90 			warnx("Can't read certificate in file: %s", file);
91 			fclose(f);
92 			return NULL;
93 		}
94 		sk_X509_insert(certs, cert, sk_X509_num(certs));
95 	}
96 
97 	fclose(f);
98 
99 	if (sk_X509_num(certs) == 0) {
100 		sk_X509_free(certs);
101 		certs = NULL;
102 		warnx("No certificate found in file %s", file);
103 	}
104 
105 	return certs;
106 }
107 
108 int
109 easy_pkcs7_verify(const char *content, size_t len,
110     const char *signature, size_t signature_len,
111     const char *anchor, int is_pkg)
112 {
113 	STACK_OF(X509) *cert_chain, *signers;
114 	X509_STORE *store;
115 	BIO *sig, *in;
116 	PKCS7 *p7;
117 	int i, status;
118 	X509_NAME *name;
119 	char *subject;
120 
121 	OpenSSL_add_all_algorithms();
122 	ERR_load_crypto_strings();
123 
124 	status = -1;
125 
126 	if (cert_chain_file)
127 		cert_chain = file_to_certs(cert_chain_file);
128 	else
129 		cert_chain = NULL;
130 
131 	store = X509_STORE_new();
132 	if (store == NULL) {
133 		sk_X509_free(cert_chain);
134 		warnx("Failed to create certificate store");
135 		return -1;
136 	}
137 
138 	X509_STORE_load_locations(store, anchor, NULL);
139 
140 	in = BIO_new_mem_buf(__UNCONST(content), len);
141 	sig = BIO_new_mem_buf(__UNCONST(signature), signature_len);
142 	signers = NULL;
143 
144 	p7 = PEM_read_bio_PKCS7(sig, NULL, NULL, NULL);
145 	if (p7 == NULL) {
146 		warnx("Failed to parse the signature");
147 		goto cleanup;
148 	}
149 
150 	if (PKCS7_verify(p7, cert_chain, store, in, NULL, 0) != 1) {
151 		warnx("Failed to verify signature");
152 		goto cleanup;
153 	}
154 
155 	signers = PKCS7_get0_signers(p7, NULL, 0);
156 	if (signers == NULL) {
157 		warnx("Failed to get signers");
158 		goto cleanup;
159 	}
160 
161 	if (sk_X509_num(signers) == 0) {
162 		warnx("No signers found");
163 		goto cleanup;
164 	}
165 
166 	for (i = 0; i < sk_X509_num(signers); i++) {
167 		/* Compute ex_xkusage */
168 		X509_check_purpose(sk_X509_value(signers, i), -1, -1);
169 
170 		if (X509_check_ca(sk_X509_value(signers, i))) {
171 			warnx("CA keys are not valid for signatures");
172 			goto cleanup;
173 		}
174 		if (is_pkg) {
175 			if (X509_get_extended_key_usage(sk_X509_value(signers, i)) != pkg_key_usage) {
176 				warnx("Certificate must have CODE SIGNING "
177 				    "and EMAIL PROTECTION property");
178 				goto cleanup;
179 			}
180 		} else {
181 			if (X509_get_extension_flags(sk_X509_value(signers, i)) & EXFLAG_XKUSAGE) {
182 				warnx("Certificate must not have any property");
183 				goto cleanup;
184 			}
185 		}
186 	}
187 
188 	printf("Sigature ok, signed by:\n");
189 
190 	for (i = 0; i < sk_X509_num(signers); i++) {
191 		name = X509_get_subject_name(sk_X509_value(signers, i));
192 		subject = X509_NAME_oneline(name, NULL, 0);
193 
194 		printf("\t%s\n", subject);
195 
196 		OPENSSL_free(subject);
197 	}
198 
199 	status = 0;
200 
201 cleanup:
202 	sk_X509_free(cert_chain);
203 	sk_X509_free(signers);
204 	X509_STORE_free(store);
205 
206 	PKCS7_free(p7);
207 	BIO_free(in);
208 	BIO_free(sig);
209 
210 	return status;
211 }
212 
213 static int
214 ssl_pass_cb(char *buf, int size, int rwflag, void *u)
215 {
216 
217 	if (EVP_read_pw_string(buf, size, "Passphrase :", 0)) {
218 #if OPENSSL_VERSION >= 0x0090608fL
219 		OPENSSL_cleanse(buf, size);
220 #else
221 		memset(buf, 0, size);
222 #endif
223 		return 0;
224 	}
225 	return strlen(buf);
226 }
227 
228 int
229 easy_pkcs7_sign(const char *content, size_t len,
230     char **signature, size_t *signature_len,
231     const char *key_file, const char *cert_file)
232 {
233 	FILE *f;
234 	X509 *certificate;
235 	STACK_OF(X509) *c, *cert_chain;
236 	EVP_PKEY *private_key;
237 	char *tmp_sig;
238 	BIO *out, *in;
239 	PKCS7 *p7;
240 	int status;
241 
242 	OpenSSL_add_all_algorithms();
243 	ERR_load_crypto_strings();
244 
245 	status = -1;
246 	private_key = NULL;
247 	cert_chain = NULL;
248 	in = NULL;
249 
250 	c = file_to_certs(cert_file);
251 
252 	if (sk_X509_num(c) != 1) {
253 		warnx("More then one certificate in the certificate file");
254 		goto cleanup;
255 	}
256 	certificate = sk_X509_value(c, 0);
257 
258 	/* Compute ex_kusage */
259 	X509_check_purpose(certificate, -1, 0);
260 
261 	if (X509_check_ca(certificate)) {
262 		warnx("CA keys are not valid for signatures");
263 		goto cleanup;
264 	}
265 
266 	if (X509_get_extended_key_usage(certificate) != pkg_key_usage) {
267 		warnx("Certificate must have CODE SIGNING "
268 		    "and EMAIL PROTECTION property");
269 		goto cleanup;
270 	}
271 
272 	if (cert_chain_file)
273 		cert_chain = file_to_certs(cert_chain_file);
274 
275 	if ((f = fopen(key_file, "r")) == NULL) {
276 		warn("Failed to open private key file %s", key_file);
277 		goto cleanup;
278 	}
279 	private_key = PEM_read_PrivateKey(f, NULL, ssl_pass_cb, NULL);
280 	fclose(f);
281 	if (private_key == NULL) {
282 		warnx("Can't read private key: %s", key_file);
283 		goto cleanup;
284 	}
285 
286 	if (X509_check_private_key(certificate, private_key) != 1) {
287 		warnx("The private key %s doesn't match the certificate %s",
288 		    key_file, cert_file);
289 		goto cleanup;
290 	}
291 
292 	in = BIO_new_mem_buf(__UNCONST(content), len);
293 
294 	p7 = PKCS7_sign(certificate, private_key, cert_chain, in,
295 	    PKCS7_DETACHED|PKCS7_NOATTR|PKCS7_BINARY);
296 	if (p7 == NULL) {
297 		warnx("Failed to create signature structure");
298 		goto cleanup;
299 	}
300 
301 	out = BIO_new(BIO_s_mem());
302 	PEM_write_bio_PKCS7(out, p7);
303 	*signature_len = BIO_get_mem_data(out, &tmp_sig);
304 	*signature = xmalloc(*signature_len);
305 	memcpy(*signature, tmp_sig, *signature_len);
306 	BIO_free_all(out);
307 
308 	PKCS7_free(p7);
309 
310 	status = 0;
311 
312 cleanup:
313 	sk_X509_free(c);
314 	sk_X509_free(cert_chain);
315 	EVP_PKEY_free(private_key);
316 	BIO_free(in);
317 
318 	return status;
319 }
320