1 /* $OpenBSD: x509_trs.c,v 1.23 2018/05/18 18:40:38 tb Exp $ */
2 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
3  * project 1999.
4  */
5 /* ====================================================================
6  * Copyright (c) 1999 The OpenSSL Project.  All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  *
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  *
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in
17  *    the documentation and/or other materials provided with the
18  *    distribution.
19  *
20  * 3. All advertising materials mentioning features or use of this
21  *    software must display the following acknowledgment:
22  *    "This product includes software developed by the OpenSSL Project
23  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
24  *
25  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
26  *    endorse or promote products derived from this software without
27  *    prior written permission. For written permission, please contact
28  *    licensing@OpenSSL.org.
29  *
30  * 5. Products derived from this software may not be called "OpenSSL"
31  *    nor may "OpenSSL" appear in their names without prior written
32  *    permission of the OpenSSL Project.
33  *
34  * 6. Redistributions of any form whatsoever must retain the following
35  *    acknowledgment:
36  *    "This product includes software developed by the OpenSSL Project
37  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
38  *
39  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
40  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
41  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
42  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
43  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
45  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
46  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
48  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
49  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
50  * OF THE POSSIBILITY OF SUCH DAMAGE.
51  * ====================================================================
52  *
53  * This product includes cryptographic software written by Eric Young
54  * (eay@cryptsoft.com).  This product includes software written by Tim
55  * Hudson (tjh@cryptsoft.com).
56  *
57  */
58 
59 #include <stdio.h>
60 #include <string.h>
61 
62 #include <openssl/err.h>
63 #include <openssl/x509v3.h>
64 
65 static int tr_cmp(const X509_TRUST * const *a, const X509_TRUST * const *b);
66 static void trtable_free(X509_TRUST *p);
67 
68 static int trust_1oidany(X509_TRUST *trust, X509 *x, int flags);
69 static int trust_1oid(X509_TRUST *trust, X509 *x, int flags);
70 static int trust_compat(X509_TRUST *trust, X509 *x, int flags);
71 
72 static int obj_trust(int id, X509 *x, int flags);
73 static int (*default_trust)(int id, X509 *x, int flags) = obj_trust;
74 
75 /* WARNING: the following table should be kept in order of trust
76  * and without any gaps so we can just subtract the minimum trust
77  * value to get an index into the table
78  */
79 
80 static X509_TRUST trstandard[] = {
81 	{X509_TRUST_COMPAT, 0, trust_compat, "compatible", 0, NULL},
82 	{X509_TRUST_SSL_CLIENT, 0, trust_1oidany, "SSL Client", NID_client_auth, NULL},
83 	{X509_TRUST_SSL_SERVER, 0, trust_1oidany, "SSL Server", NID_server_auth, NULL},
84 	{X509_TRUST_EMAIL, 0, trust_1oidany, "S/MIME email", NID_email_protect, NULL},
85 	{X509_TRUST_OBJECT_SIGN, 0, trust_1oidany, "Object Signer", NID_code_sign, NULL},
86 	{X509_TRUST_OCSP_SIGN, 0, trust_1oid, "OCSP responder", NID_OCSP_sign, NULL},
87 	{X509_TRUST_OCSP_REQUEST, 0, trust_1oid, "OCSP request", NID_ad_OCSP, NULL},
88 	{X509_TRUST_TSA, 0, trust_1oidany, "TSA server", NID_time_stamp, NULL}
89 };
90 
91 #define X509_TRUST_COUNT	(sizeof(trstandard)/sizeof(X509_TRUST))
92 
93 static STACK_OF(X509_TRUST) *trtable = NULL;
94 
95 static int
96 tr_cmp(const X509_TRUST * const *a, const X509_TRUST * const *b)
97 {
98 	return (*a)->trust - (*b)->trust;
99 }
100 
101 int
102 (*X509_TRUST_set_default(int (*trust)(int , X509 *, int)))(int, X509 *, int)
103 {
104 	int (*oldtrust)(int , X509 *, int);
105 
106 	oldtrust = default_trust;
107 	default_trust = trust;
108 	return oldtrust;
109 }
110 
111 int
112 X509_check_trust(X509 *x, int id, int flags)
113 {
114 	X509_TRUST *pt;
115 	int idx;
116 
117 	if (id == -1)
118 		return 1;
119 	/*
120 	 * XXX beck/jsing This enables self signed certs to be trusted for
121 	 * an unspecified id/trust flag value (this is NOT the
122 	 * X509_TRUST_DEFAULT), which was the longstanding
123 	 * openssl behaviour. boringssl does not have this behaviour.
124 	 *
125 	 * This should be revisited, but changing the default "not default"
126 	 * may break things.
127 	 */
128 	if (id == 0) {
129 		int rv;
130 		rv = obj_trust(NID_anyExtendedKeyUsage, x, 0);
131 		if (rv != X509_TRUST_UNTRUSTED)
132 			return rv;
133 		return trust_compat(NULL, x, 0);
134 	}
135 	idx = X509_TRUST_get_by_id(id);
136 	if (idx == -1)
137 		return default_trust(id, x, flags);
138 	pt = X509_TRUST_get0(idx);
139 	return pt->check_trust(pt, x, flags);
140 }
141 
142 int
143 X509_TRUST_get_count(void)
144 {
145 	if (!trtable)
146 		return X509_TRUST_COUNT;
147 	return sk_X509_TRUST_num(trtable) + X509_TRUST_COUNT;
148 }
149 
150 X509_TRUST *
151 X509_TRUST_get0(int idx)
152 {
153 	if (idx < 0)
154 		return NULL;
155 	if (idx < (int)X509_TRUST_COUNT)
156 		return trstandard + idx;
157 	return sk_X509_TRUST_value(trtable, idx - X509_TRUST_COUNT);
158 }
159 
160 int
161 X509_TRUST_get_by_id(int id)
162 {
163 	X509_TRUST tmp;
164 	int idx;
165 
166 	if ((id >= X509_TRUST_MIN) && (id <= X509_TRUST_MAX))
167 		return id - X509_TRUST_MIN;
168 	tmp.trust = id;
169 	if (!trtable)
170 		return -1;
171 	idx = sk_X509_TRUST_find(trtable, &tmp);
172 	if (idx == -1)
173 		return -1;
174 	return idx + X509_TRUST_COUNT;
175 }
176 
177 int
178 X509_TRUST_set(int *t, int trust)
179 {
180 	if (X509_TRUST_get_by_id(trust) == -1) {
181 		X509error(X509_R_INVALID_TRUST);
182 		return 0;
183 	}
184 	*t = trust;
185 	return 1;
186 }
187 
188 int
189 X509_TRUST_add(int id, int flags, int (*ck)(X509_TRUST *, X509 *, int),
190     const char *name, int arg1, void *arg2)
191 {
192 	int idx;
193 	X509_TRUST *trtmp;
194 	char *name_dup;
195 
196 	/* This is set according to what we change: application can't set it */
197 	flags &= ~X509_TRUST_DYNAMIC;
198 	/* This will always be set for application modified trust entries */
199 	flags |= X509_TRUST_DYNAMIC_NAME;
200 	/* Get existing entry if any */
201 	idx = X509_TRUST_get_by_id(id);
202 	/* Need a new entry */
203 	if (idx == -1) {
204 		if (!(trtmp = malloc(sizeof(X509_TRUST)))) {
205 			X509error(ERR_R_MALLOC_FAILURE);
206 			return 0;
207 		}
208 		trtmp->flags = X509_TRUST_DYNAMIC;
209 	} else {
210 		trtmp = X509_TRUST_get0(idx);
211 		if (trtmp == NULL) {
212 			X509error(X509_R_INVALID_TRUST);
213 			return 0;
214 		}
215 	}
216 
217 	if ((name_dup = strdup(name)) == NULL)
218 		goto err;
219 
220 	/* free existing name if dynamic */
221 	if (trtmp->flags & X509_TRUST_DYNAMIC_NAME)
222 		free(trtmp->name);
223 	/* dup supplied name */
224 	trtmp->name = name_dup;
225 	/* Keep the dynamic flag of existing entry */
226 	trtmp->flags &= X509_TRUST_DYNAMIC;
227 	/* Set all other flags */
228 	trtmp->flags |= flags;
229 
230 	trtmp->trust = id;
231 	trtmp->check_trust = ck;
232 	trtmp->arg1 = arg1;
233 	trtmp->arg2 = arg2;
234 
235 	/* If it's a new entry, manage the dynamic table */
236 	if (idx == -1) {
237 		if (trtable == NULL &&
238 		    (trtable = sk_X509_TRUST_new(tr_cmp)) == NULL)
239 			goto err;
240 		if (sk_X509_TRUST_push(trtable, trtmp) == 0)
241 			goto err;
242 	}
243 	return 1;
244 
245 err:
246 	free(name_dup);
247 	if (idx == -1)
248 		free(trtmp);
249 	X509error(ERR_R_MALLOC_FAILURE);
250 	return 0;
251 }
252 
253 static void
254 trtable_free(X509_TRUST *p)
255 {
256 	if (!p)
257 		return;
258 	if (p->flags & X509_TRUST_DYNAMIC) {
259 		if (p->flags & X509_TRUST_DYNAMIC_NAME)
260 			free(p->name);
261 		free(p);
262 	}
263 }
264 
265 void
266 X509_TRUST_cleanup(void)
267 {
268 	unsigned int i;
269 
270 	for (i = 0; i < X509_TRUST_COUNT; i++)
271 		trtable_free(trstandard + i);
272 	sk_X509_TRUST_pop_free(trtable, trtable_free);
273 	trtable = NULL;
274 }
275 
276 int
277 X509_TRUST_get_flags(const X509_TRUST *xp)
278 {
279 	return xp->flags;
280 }
281 
282 char *
283 X509_TRUST_get0_name(const X509_TRUST *xp)
284 {
285 	return xp->name;
286 }
287 
288 int
289 X509_TRUST_get_trust(const X509_TRUST *xp)
290 {
291 	return xp->trust;
292 }
293 
294 static int
295 trust_1oidany(X509_TRUST *trust, X509 *x, int flags)
296 {
297 	if (x->aux && (x->aux->trust || x->aux->reject))
298 		return obj_trust(trust->arg1, x, flags);
299 	/* we don't have any trust settings: for compatibility
300 	 * we return trusted if it is self signed
301 	 */
302 	return trust_compat(trust, x, flags);
303 }
304 
305 static int
306 trust_1oid(X509_TRUST *trust, X509 *x, int flags)
307 {
308 	if (x->aux)
309 		return obj_trust(trust->arg1, x, flags);
310 	return X509_TRUST_UNTRUSTED;
311 }
312 
313 static int
314 trust_compat(X509_TRUST *trust, X509 *x, int flags)
315 {
316 	X509_check_purpose(x, -1, 0);
317 	if (x->ex_flags & EXFLAG_SS)
318 		return X509_TRUST_TRUSTED;
319 	else
320 		return X509_TRUST_UNTRUSTED;
321 }
322 
323 static int
324 obj_trust(int id, X509 *x, int flags)
325 {
326 	ASN1_OBJECT *obj;
327 	int i;
328 	X509_CERT_AUX *ax;
329 
330 	ax = x->aux;
331 	if (!ax)
332 		return X509_TRUST_UNTRUSTED;
333 	if (ax->reject) {
334 		for (i = 0; i < sk_ASN1_OBJECT_num(ax->reject); i++) {
335 			obj = sk_ASN1_OBJECT_value(ax->reject, i);
336 			if (OBJ_obj2nid(obj) == id)
337 				return X509_TRUST_REJECTED;
338 		}
339 	}
340 	if (ax->trust) {
341 		for (i = 0; i < sk_ASN1_OBJECT_num(ax->trust); i++) {
342 			obj = sk_ASN1_OBJECT_value(ax->trust, i);
343 			if (OBJ_obj2nid(obj) == id)
344 				return X509_TRUST_TRUSTED;
345 		}
346 	}
347 	return X509_TRUST_UNTRUSTED;
348 }
349