Update libressl README.DRAGONFLY for v2.4.4
[dragonfly.git] / crypto / libressl / tls / tls_verify.c
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f5b1c8a1
JM
1/* $OpenBSD: tls_verify.c,v 1.14 2015/09/29 10:17:04 deraadt Exp $ */
2/*
3 * Copyright (c) 2014 Jeremie Courreges-Anglas <jca@openbsd.org>
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18#include <sys/socket.h>
19
20#include <arpa/inet.h>
21#include <netinet/in.h>
22
23#include <string.h>
24
25#include <openssl/x509v3.h>
26
27#include "tls_internal.h"
28
29static int tls_match_name(const char *cert_name, const char *name);
30static int tls_check_subject_altname(struct tls *ctx, X509 *cert,
31 const char *name);
32static int tls_check_common_name(struct tls *ctx, X509 *cert, const char *name);
33
34static int
35tls_match_name(const char *cert_name, const char *name)
36{
37 const char *cert_domain, *domain, *next_dot;
38
39 if (strcasecmp(cert_name, name) == 0)
40 return 0;
41
42 /* Wildcard match? */
43 if (cert_name[0] == '*') {
44 /*
45 * Valid wildcards:
46 * - "*.domain.tld"
47 * - "*.sub.domain.tld"
48 * - etc.
49 * Reject "*.tld".
50 * No attempt to prevent the use of eg. "*.co.uk".
51 */
52 cert_domain = &cert_name[1];
53 /* Disallow "*" */
54 if (cert_domain[0] == '\0')
55 return -1;
56 /* Disallow "*foo" */
57 if (cert_domain[0] != '.')
58 return -1;
59 /* Disallow "*.." */
60 if (cert_domain[1] == '.')
61 return -1;
62 next_dot = strchr(&cert_domain[1], '.');
63 /* Disallow "*.bar" */
64 if (next_dot == NULL)
65 return -1;
66 /* Disallow "*.bar.." */
67 if (next_dot[1] == '.')
68 return -1;
69
70 domain = strchr(name, '.');
71
72 /* No wildcard match against a name with no host part. */
73 if (name[0] == '.')
74 return -1;
75 /* No wildcard match against a name with no domain part. */
76 if (domain == NULL || strlen(domain) == 1)
77 return -1;
78
79 if (strcasecmp(cert_domain, domain) == 0)
80 return 0;
81 }
82
83 return -1;
84}
85
86/* See RFC 5280 section 4.2.1.6 for SubjectAltName details. */
87static int
88tls_check_subject_altname(struct tls *ctx, X509 *cert, const char *name)
89{
90 STACK_OF(GENERAL_NAME) *altname_stack = NULL;
91 union tls_addr addrbuf;
92 int addrlen, type;
93 int count, i;
94 int rv = -1;
95
96 altname_stack = X509_get_ext_d2i(cert, NID_subject_alt_name,
97 NULL, NULL);
98 if (altname_stack == NULL)
99 return -1;
100
101 if (inet_pton(AF_INET, name, &addrbuf) == 1) {
102 type = GEN_IPADD;
103 addrlen = 4;
104 } else if (inet_pton(AF_INET6, name, &addrbuf) == 1) {
105 type = GEN_IPADD;
106 addrlen = 16;
107 } else {
108 type = GEN_DNS;
109 addrlen = 0;
110 }
111
112 count = sk_GENERAL_NAME_num(altname_stack);
113 for (i = 0; i < count; i++) {
114 GENERAL_NAME *altname;
115
116 altname = sk_GENERAL_NAME_value(altname_stack, i);
117
118 if (altname->type != type)
119 continue;
120
121 if (type == GEN_DNS) {
122 unsigned char *data;
123 int format, len;
124
125 format = ASN1_STRING_type(altname->d.dNSName);
126 if (format == V_ASN1_IA5STRING) {
127 data = ASN1_STRING_data(altname->d.dNSName);
128 len = ASN1_STRING_length(altname->d.dNSName);
129
130 if (len < 0 || len != strlen(data)) {
131 tls_set_errorx(ctx,
132 "error verifying name '%s': "
133 "NUL byte in subjectAltName, "
134 "probably a malicious certificate",
135 name);
136 rv = -2;
137 break;
138 }
139
140 /*
141 * Per RFC 5280 section 4.2.1.6:
142 * " " is a legal domain name, but that
143 * dNSName must be rejected.
144 */
145 if (strcmp(data, " ") == 0) {
146 tls_set_error(ctx,
147 "error verifying name '%s': "
148 "a dNSName of \" \" must not be "
149 "used", name);
150 rv = -2;
151 break;
152 }
153
154 if (tls_match_name(data, name) == 0) {
155 rv = 0;
156 break;
157 }
158 } else {
159#ifdef DEBUG
160 fprintf(stdout, "%s: unhandled subjectAltName "
161 "dNSName encoding (%d)\n", getprogname(),
162 format);
163#endif
164 }
165
166 } else if (type == GEN_IPADD) {
167 unsigned char *data;
168 int datalen;
169
170 datalen = ASN1_STRING_length(altname->d.iPAddress);
171 data = ASN1_STRING_data(altname->d.iPAddress);
172
173 if (datalen < 0) {
174 tls_set_errorx(ctx,
175 "Unexpected negative length for an "
176 "IP address: %d", datalen);
177 rv = -2;
178 break;
179 }
180
181 /*
182 * Per RFC 5280 section 4.2.1.6:
183 * IPv4 must use 4 octets and IPv6 must use 16 octets.
184 */
185 if (datalen == addrlen &&
186 memcmp(data, &addrbuf, addrlen) == 0) {
187 rv = 0;
188 break;
189 }
190 }
191 }
192
193 sk_GENERAL_NAME_pop_free(altname_stack, GENERAL_NAME_free);
194 return rv;
195}
196
197static int
198tls_check_common_name(struct tls *ctx, X509 *cert, const char *name)
199{
200 X509_NAME *subject_name;
201 char *common_name = NULL;
202 union tls_addr addrbuf;
203 int common_name_len;
204 int rv = -1;
205
206 subject_name = X509_get_subject_name(cert);
207 if (subject_name == NULL)
208 goto out;
209
210 common_name_len = X509_NAME_get_text_by_NID(subject_name,
211 NID_commonName, NULL, 0);
212 if (common_name_len < 0)
213 goto out;
214
215 common_name = calloc(common_name_len + 1, 1);
216 if (common_name == NULL)
217 goto out;
218
219 X509_NAME_get_text_by_NID(subject_name, NID_commonName, common_name,
220 common_name_len + 1);
221
222 /* NUL bytes in CN? */
223 if (common_name_len != strlen(common_name)) {
224 tls_set_errorx(ctx, "error verifying name '%s': "
225 "NUL byte in Common Name field, "
226 "probably a malicious certificate", name);
227 rv = -2;
228 goto out;
229 }
230
231 if (inet_pton(AF_INET, name, &addrbuf) == 1 ||
232 inet_pton(AF_INET6, name, &addrbuf) == 1) {
233 /*
234 * We don't want to attempt wildcard matching against IP
235 * addresses, so perform a simple comparison here.
236 */
237 if (strcmp(common_name, name) == 0)
238 rv = 0;
239 else
240 rv = -1;
241 goto out;
242 }
243
244 if (tls_match_name(common_name, name) == 0)
245 rv = 0;
246 out:
247 free(common_name);
248 return rv;
249}
250
251int
252tls_check_name(struct tls *ctx, X509 *cert, const char *name)
253{
254 int rv;
255
256 rv = tls_check_subject_altname(ctx, cert, name);
257 if (rv == 0 || rv == -2)
258 return rv;
259
260 return tls_check_common_name(ctx, cert, name);
261}