1/* v3_purp.c */
2/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
3 * project 2001.
4 */
5/* ====================================================================
6 * Copyright (c) 1999-2004 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 "cryptlib.h"
61#include <openssl/x509v3.h>
62#include <openssl/x509_vfy.h>
63
64static void x509v3_cache_extensions(X509 *x);
65
66static int check_ssl_ca(const X509 *x);
67static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int ca);
68static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca);
69static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca);
70static int purpose_smime(const X509 *x, int ca);
71static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, int ca);
72static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int ca);
73static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int ca);
74static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x, int ca);
75static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca);
76static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca);
77
78static int xp_cmp(const X509_PURPOSE * const *a,
79		const X509_PURPOSE * const *b);
80static void xptable_free(X509_PURPOSE *p);
81
82static X509_PURPOSE xstandard[] = {
83	{X509_PURPOSE_SSL_CLIENT, X509_TRUST_SSL_CLIENT, 0, check_purpose_ssl_client, "SSL client", "sslclient", NULL},
84	{X509_PURPOSE_SSL_SERVER, X509_TRUST_SSL_SERVER, 0, check_purpose_ssl_server, "SSL server", "sslserver", NULL},
85	{X509_PURPOSE_NS_SSL_SERVER, X509_TRUST_SSL_SERVER, 0, check_purpose_ns_ssl_server, "Netscape SSL server", "nssslserver", NULL},
86	{X509_PURPOSE_SMIME_SIGN, X509_TRUST_EMAIL, 0, check_purpose_smime_sign, "S/MIME signing", "smimesign", NULL},
87	{X509_PURPOSE_SMIME_ENCRYPT, X509_TRUST_EMAIL, 0, check_purpose_smime_encrypt, "S/MIME encryption", "smimeencrypt", NULL},
88	{X509_PURPOSE_CRL_SIGN, X509_TRUST_COMPAT, 0, check_purpose_crl_sign, "CRL signing", "crlsign", NULL},
89	{X509_PURPOSE_ANY, X509_TRUST_DEFAULT, 0, no_check, "Any Purpose", "any", NULL},
90	{X509_PURPOSE_OCSP_HELPER, X509_TRUST_COMPAT, 0, ocsp_helper, "OCSP helper", "ocsphelper", NULL},
91	{X509_PURPOSE_TIMESTAMP_SIGN, X509_TRUST_TSA, 0, check_purpose_timestamp_sign, "Time Stamp signing", "timestampsign", NULL},
92};
93
94#define X509_PURPOSE_COUNT (sizeof(xstandard)/sizeof(X509_PURPOSE))
95
96IMPLEMENT_STACK_OF(X509_PURPOSE)
97
98static STACK_OF(X509_PURPOSE) *xptable = NULL;
99
100static int xp_cmp(const X509_PURPOSE * const *a,
101		const X509_PURPOSE * const *b)
102{
103	return (*a)->purpose - (*b)->purpose;
104}
105
106/* As much as I'd like to make X509_check_purpose use a "const" X509*
107 * I really can't because it does recalculate hashes and do other non-const
108 * things. */
109int X509_check_purpose(X509 *x, int id, int ca)
110{
111	int idx;
112	const X509_PURPOSE *pt;
113	if(!(x->ex_flags & EXFLAG_SET)) {
114		CRYPTO_w_lock(CRYPTO_LOCK_X509);
115		x509v3_cache_extensions(x);
116		CRYPTO_w_unlock(CRYPTO_LOCK_X509);
117	}
118	if(id == -1) return 1;
119	idx = X509_PURPOSE_get_by_id(id);
120	if(idx == -1) return -1;
121	pt = X509_PURPOSE_get0(idx);
122	return pt->check_purpose(pt, x, ca);
123}
124
125int X509_PURPOSE_set(int *p, int purpose)
126{
127	if(X509_PURPOSE_get_by_id(purpose) == -1) {
128		X509V3err(X509V3_F_X509_PURPOSE_SET, X509V3_R_INVALID_PURPOSE);
129		return 0;
130	}
131	*p = purpose;
132	return 1;
133}
134
135int X509_PURPOSE_get_count(void)
136{
137	if(!xptable) return X509_PURPOSE_COUNT;
138	return sk_X509_PURPOSE_num(xptable) + X509_PURPOSE_COUNT;
139}
140
141X509_PURPOSE * X509_PURPOSE_get0(int idx)
142{
143	if(idx < 0) return NULL;
144	if(idx < (int)X509_PURPOSE_COUNT) return xstandard + idx;
145	return sk_X509_PURPOSE_value(xptable, idx - X509_PURPOSE_COUNT);
146}
147
148int X509_PURPOSE_get_by_sname(char *sname)
149{
150	int i;
151	X509_PURPOSE *xptmp;
152	for(i = 0; i < X509_PURPOSE_get_count(); i++) {
153		xptmp = X509_PURPOSE_get0(i);
154		if(!strcmp(xptmp->sname, sname)) return i;
155	}
156	return -1;
157}
158
159int X509_PURPOSE_get_by_id(int purpose)
160{
161	X509_PURPOSE tmp;
162	int idx;
163	if((purpose >= X509_PURPOSE_MIN) && (purpose <= X509_PURPOSE_MAX))
164		return purpose - X509_PURPOSE_MIN;
165	tmp.purpose = purpose;
166	if(!xptable) return -1;
167	idx = sk_X509_PURPOSE_find(xptable, &tmp);
168	if(idx == -1) return -1;
169	return idx + X509_PURPOSE_COUNT;
170}
171
172int X509_PURPOSE_add(int id, int trust, int flags,
173			int (*ck)(const X509_PURPOSE *, const X509 *, int),
174					char *name, char *sname, void *arg)
175{
176	int idx;
177	X509_PURPOSE *ptmp;
178	/* This is set according to what we change: application can't set it */
179	flags &= ~X509_PURPOSE_DYNAMIC;
180	/* This will always be set for application modified trust entries */
181	flags |= X509_PURPOSE_DYNAMIC_NAME;
182	/* Get existing entry if any */
183	idx = X509_PURPOSE_get_by_id(id);
184	/* Need a new entry */
185	if(idx == -1) {
186		if(!(ptmp = OPENSSL_malloc(sizeof(X509_PURPOSE)))) {
187			X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
188			return 0;
189		}
190		ptmp->flags = X509_PURPOSE_DYNAMIC;
191	} else ptmp = X509_PURPOSE_get0(idx);
192
193	/* OPENSSL_free existing name if dynamic */
194	if(ptmp->flags & X509_PURPOSE_DYNAMIC_NAME) {
195		OPENSSL_free(ptmp->name);
196		OPENSSL_free(ptmp->sname);
197	}
198	/* dup supplied name */
199	ptmp->name = BUF_strdup(name);
200	ptmp->sname = BUF_strdup(sname);
201	if(!ptmp->name || !ptmp->sname) {
202		X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
203		return 0;
204	}
205	/* Keep the dynamic flag of existing entry */
206	ptmp->flags &= X509_PURPOSE_DYNAMIC;
207	/* Set all other flags */
208	ptmp->flags |= flags;
209
210	ptmp->purpose = id;
211	ptmp->trust = trust;
212	ptmp->check_purpose = ck;
213	ptmp->usr_data = arg;
214
215	/* If its a new entry manage the dynamic table */
216	if(idx == -1) {
217		if(!xptable && !(xptable = sk_X509_PURPOSE_new(xp_cmp))) {
218			X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
219			return 0;
220		}
221		if (!sk_X509_PURPOSE_push(xptable, ptmp)) {
222			X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
223			return 0;
224		}
225	}
226	return 1;
227}
228
229static void xptable_free(X509_PURPOSE *p)
230	{
231	if(!p) return;
232	if (p->flags & X509_PURPOSE_DYNAMIC)
233		{
234		if (p->flags & X509_PURPOSE_DYNAMIC_NAME) {
235			OPENSSL_free(p->name);
236			OPENSSL_free(p->sname);
237		}
238		OPENSSL_free(p);
239		}
240	}
241
242void X509_PURPOSE_cleanup(void)
243{
244	unsigned int i;
245	sk_X509_PURPOSE_pop_free(xptable, xptable_free);
246	for(i = 0; i < X509_PURPOSE_COUNT; i++) xptable_free(xstandard + i);
247	xptable = NULL;
248}
249
250int X509_PURPOSE_get_id(X509_PURPOSE *xp)
251{
252	return xp->purpose;
253}
254
255char *X509_PURPOSE_get0_name(X509_PURPOSE *xp)
256{
257	return xp->name;
258}
259
260char *X509_PURPOSE_get0_sname(X509_PURPOSE *xp)
261{
262	return xp->sname;
263}
264
265int X509_PURPOSE_get_trust(X509_PURPOSE *xp)
266{
267	return xp->trust;
268}
269
270static int nid_cmp(const int *a, const int *b)
271	{
272	return *a - *b;
273	}
274
275DECLARE_OBJ_BSEARCH_CMP_FN(int, int, nid);
276IMPLEMENT_OBJ_BSEARCH_CMP_FN(int, int, nid);
277
278int X509_supported_extension(X509_EXTENSION *ex)
279	{
280	/* This table is a list of the NIDs of supported extensions:
281	 * that is those which are used by the verify process. If
282	 * an extension is critical and doesn't appear in this list
283	 * then the verify process will normally reject the certificate.
284	 * The list must be kept in numerical order because it will be
285	 * searched using bsearch.
286	 */
287
288	static const int supported_nids[] = {
289		NID_netscape_cert_type, /* 71 */
290        	NID_key_usage,		/* 83 */
291		NID_subject_alt_name,	/* 85 */
292		NID_basic_constraints,	/* 87 */
293		NID_certificate_policies, /* 89 */
294        	NID_ext_key_usage,	/* 126 */
295#ifndef OPENSSL_NO_RFC3779
296		NID_sbgp_ipAddrBlock,	/* 290 */
297		NID_sbgp_autonomousSysNum, /* 291 */
298#endif
299		NID_policy_constraints,	/* 401 */
300		NID_proxyCertInfo,	/* 663 */
301		NID_name_constraints,	/* 666 */
302		NID_policy_mappings,	/* 747 */
303		NID_inhibit_any_policy	/* 748 */
304	};
305
306	int ex_nid = OBJ_obj2nid(X509_EXTENSION_get_object(ex));
307
308	if (ex_nid == NID_undef)
309		return 0;
310
311	if (OBJ_bsearch_nid(&ex_nid, supported_nids,
312			sizeof(supported_nids)/sizeof(int)))
313		return 1;
314	return 0;
315	}
316
317static void setup_dp(X509 *x, DIST_POINT *dp)
318	{
319	X509_NAME *iname = NULL;
320	int i;
321	if (dp->reasons)
322		{
323		if (dp->reasons->length > 0)
324			dp->dp_reasons = dp->reasons->data[0];
325		if (dp->reasons->length > 1)
326			dp->dp_reasons |= (dp->reasons->data[1] << 8);
327		dp->dp_reasons &= CRLDP_ALL_REASONS;
328		}
329	else
330		dp->dp_reasons = CRLDP_ALL_REASONS;
331	if (!dp->distpoint || (dp->distpoint->type != 1))
332		return;
333	for (i = 0; i < sk_GENERAL_NAME_num(dp->CRLissuer); i++)
334		{
335		GENERAL_NAME *gen = sk_GENERAL_NAME_value(dp->CRLissuer, i);
336		if (gen->type == GEN_DIRNAME)
337			{
338			iname = gen->d.directoryName;
339			break;
340			}
341		}
342	if (!iname)
343		iname = X509_get_issuer_name(x);
344
345	DIST_POINT_set_dpname(dp->distpoint, iname);
346
347	}
348
349static void setup_crldp(X509 *x)
350	{
351	int i;
352	x->crldp = X509_get_ext_d2i(x, NID_crl_distribution_points, NULL, NULL);
353	for (i = 0; i < sk_DIST_POINT_num(x->crldp); i++)
354		setup_dp(x, sk_DIST_POINT_value(x->crldp, i));
355	}
356
357static void x509v3_cache_extensions(X509 *x)
358{
359	BASIC_CONSTRAINTS *bs;
360	PROXY_CERT_INFO_EXTENSION *pci;
361	ASN1_BIT_STRING *usage;
362	ASN1_BIT_STRING *ns;
363	EXTENDED_KEY_USAGE *extusage;
364	X509_EXTENSION *ex;
365
366	int i;
367	if(x->ex_flags & EXFLAG_SET) return;
368#ifndef OPENSSL_NO_SHA
369	X509_digest(x, EVP_sha1(), x->sha1_hash, NULL);
370#endif
371	/* Does subject name match issuer ? */
372	if(!X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x)))
373			 x->ex_flags |= EXFLAG_SI;
374	/* V1 should mean no extensions ... */
375	if(!X509_get_version(x)) x->ex_flags |= EXFLAG_V1;
376	/* Handle basic constraints */
377	if((bs=X509_get_ext_d2i(x, NID_basic_constraints, NULL, NULL))) {
378		if(bs->ca) x->ex_flags |= EXFLAG_CA;
379		if(bs->pathlen) {
380			if((bs->pathlen->type == V_ASN1_NEG_INTEGER)
381						|| !bs->ca) {
382				x->ex_flags |= EXFLAG_INVALID;
383				x->ex_pathlen = 0;
384			} else x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen);
385		} else x->ex_pathlen = -1;
386		BASIC_CONSTRAINTS_free(bs);
387		x->ex_flags |= EXFLAG_BCONS;
388	}
389	/* Handle proxy certificates */
390	if((pci=X509_get_ext_d2i(x, NID_proxyCertInfo, NULL, NULL))) {
391		if (x->ex_flags & EXFLAG_CA
392		    || X509_get_ext_by_NID(x, NID_subject_alt_name, -1) >= 0
393		    || X509_get_ext_by_NID(x, NID_issuer_alt_name, -1) >= 0) {
394			x->ex_flags |= EXFLAG_INVALID;
395		}
396		if (pci->pcPathLengthConstraint) {
397			x->ex_pcpathlen =
398				ASN1_INTEGER_get(pci->pcPathLengthConstraint);
399		} else x->ex_pcpathlen = -1;
400		PROXY_CERT_INFO_EXTENSION_free(pci);
401		x->ex_flags |= EXFLAG_PROXY;
402	}
403	/* Handle key usage */
404	if((usage=X509_get_ext_d2i(x, NID_key_usage, NULL, NULL))) {
405		if(usage->length > 0) {
406			x->ex_kusage = usage->data[0];
407			if(usage->length > 1)
408				x->ex_kusage |= usage->data[1] << 8;
409		} else x->ex_kusage = 0;
410		x->ex_flags |= EXFLAG_KUSAGE;
411		ASN1_BIT_STRING_free(usage);
412	}
413	x->ex_xkusage = 0;
414	if((extusage=X509_get_ext_d2i(x, NID_ext_key_usage, NULL, NULL))) {
415		x->ex_flags |= EXFLAG_XKUSAGE;
416		for(i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) {
417			switch(OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage,i))) {
418				case NID_server_auth:
419				x->ex_xkusage |= XKU_SSL_SERVER;
420				break;
421
422				case NID_client_auth:
423				x->ex_xkusage |= XKU_SSL_CLIENT;
424				break;
425
426				case NID_email_protect:
427				x->ex_xkusage |= XKU_SMIME;
428				break;
429
430				case NID_code_sign:
431				x->ex_xkusage |= XKU_CODE_SIGN;
432				break;
433
434				case NID_ms_sgc:
435				case NID_ns_sgc:
436				x->ex_xkusage |= XKU_SGC;
437				break;
438
439				case NID_OCSP_sign:
440				x->ex_xkusage |= XKU_OCSP_SIGN;
441				break;
442
443				case NID_time_stamp:
444				x->ex_xkusage |= XKU_TIMESTAMP;
445				break;
446
447				case NID_dvcs:
448				x->ex_xkusage |= XKU_DVCS;
449				break;
450			}
451		}
452		sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free);
453	}
454
455	if((ns=X509_get_ext_d2i(x, NID_netscape_cert_type, NULL, NULL))) {
456		if(ns->length > 0) x->ex_nscert = ns->data[0];
457		else x->ex_nscert = 0;
458		x->ex_flags |= EXFLAG_NSCERT;
459		ASN1_BIT_STRING_free(ns);
460	}
461	x->skid =X509_get_ext_d2i(x, NID_subject_key_identifier, NULL, NULL);
462	x->akid =X509_get_ext_d2i(x, NID_authority_key_identifier, NULL, NULL);
463	x->altname = X509_get_ext_d2i(x, NID_subject_alt_name, NULL, NULL);
464	x->nc = X509_get_ext_d2i(x, NID_name_constraints, &i, NULL);
465	if (!x->nc && (i != -1))
466		x->ex_flags |= EXFLAG_INVALID;
467	setup_crldp(x);
468
469#ifndef OPENSSL_NO_RFC3779
470 	x->rfc3779_addr =X509_get_ext_d2i(x, NID_sbgp_ipAddrBlock, NULL, NULL);
471 	x->rfc3779_asid =X509_get_ext_d2i(x, NID_sbgp_autonomousSysNum,
472 					  NULL, NULL);
473#endif
474	for (i = 0; i < X509_get_ext_count(x); i++)
475		{
476		ex = X509_get_ext(x, i);
477		if (OBJ_obj2nid(X509_EXTENSION_get_object(ex))
478					== NID_freshest_crl)
479			x->ex_flags |= EXFLAG_FRESHEST;
480		if (!X509_EXTENSION_get_critical(ex))
481			continue;
482		if (!X509_supported_extension(ex))
483			{
484			x->ex_flags |= EXFLAG_CRITICAL;
485			break;
486			}
487		}
488	x->ex_flags |= EXFLAG_SET;
489}
490
491/* CA checks common to all purposes
492 * return codes:
493 * 0 not a CA
494 * 1 is a CA
495 * 2 basicConstraints absent so "maybe" a CA
496 * 3 basicConstraints absent but self signed V1.
497 * 4 basicConstraints absent but keyUsage present and keyCertSign asserted.
498 */
499
500#define V1_ROOT (EXFLAG_V1|EXFLAG_SS)
501#define ku_reject(x, usage) \
502	(((x)->ex_flags & EXFLAG_KUSAGE) && !((x)->ex_kusage & (usage)))
503#define xku_reject(x, usage) \
504	(((x)->ex_flags & EXFLAG_XKUSAGE) && !((x)->ex_xkusage & (usage)))
505#define ns_reject(x, usage) \
506	(((x)->ex_flags & EXFLAG_NSCERT) && !((x)->ex_nscert & (usage)))
507
508static int check_ca(const X509 *x)
509{
510	/* keyUsage if present should allow cert signing */
511	if(ku_reject(x, KU_KEY_CERT_SIGN)) return 0;
512	if(x->ex_flags & EXFLAG_BCONS) {
513		if(x->ex_flags & EXFLAG_CA) return 1;
514		/* If basicConstraints says not a CA then say so */
515		else return 0;
516	} else {
517		/* we support V1 roots for...  uh, I don't really know why. */
518		if((x->ex_flags & V1_ROOT) == V1_ROOT) return 3;
519		/* If key usage present it must have certSign so tolerate it */
520		else if (x->ex_flags & EXFLAG_KUSAGE) return 4;
521		/* Older certificates could have Netscape-specific CA types */
522		else if (x->ex_flags & EXFLAG_NSCERT
523			 && x->ex_nscert & NS_ANY_CA) return 5;
524		/* can this still be regarded a CA certificate?  I doubt it */
525		return 0;
526	}
527}
528
529int X509_check_ca(X509 *x)
530{
531	if(!(x->ex_flags & EXFLAG_SET)) {
532		CRYPTO_w_lock(CRYPTO_LOCK_X509);
533		x509v3_cache_extensions(x);
534		CRYPTO_w_unlock(CRYPTO_LOCK_X509);
535	}
536
537	return check_ca(x);
538}
539
540/* Check SSL CA: common checks for SSL client and server */
541static int check_ssl_ca(const X509 *x)
542{
543	int ca_ret;
544	ca_ret = check_ca(x);
545	if(!ca_ret) return 0;
546	/* check nsCertType if present */
547	if(ca_ret != 5 || x->ex_nscert & NS_SSL_CA) return ca_ret;
548	else return 0;
549}
550
551
552static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int ca)
553{
554	if(xku_reject(x,XKU_SSL_CLIENT)) return 0;
555	if(ca) return check_ssl_ca(x);
556	/* We need to do digital signatures with it */
557	if(ku_reject(x,KU_DIGITAL_SIGNATURE)) return 0;
558	/* nsCertType if present should allow SSL client use */
559	if(ns_reject(x, NS_SSL_CLIENT)) return 0;
560	return 1;
561}
562
563static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca)
564{
565	if(xku_reject(x,XKU_SSL_SERVER|XKU_SGC)) return 0;
566	if(ca) return check_ssl_ca(x);
567
568	if(ns_reject(x, NS_SSL_SERVER)) return 0;
569	/* Now as for keyUsage: we'll at least need to sign OR encipher */
570	if(ku_reject(x, KU_DIGITAL_SIGNATURE|KU_KEY_ENCIPHERMENT)) return 0;
571
572	return 1;
573
574}
575
576static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca)
577{
578	int ret;
579	ret = check_purpose_ssl_server(xp, x, ca);
580	if(!ret || ca) return ret;
581	/* We need to encipher or Netscape complains */
582	if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0;
583	return ret;
584}
585
586/* common S/MIME checks */
587static int purpose_smime(const X509 *x, int ca)
588{
589	if(xku_reject(x,XKU_SMIME)) return 0;
590	if(ca) {
591		int ca_ret;
592		ca_ret = check_ca(x);
593		if(!ca_ret) return 0;
594		/* check nsCertType if present */
595		if(ca_ret != 5 || x->ex_nscert & NS_SMIME_CA) return ca_ret;
596		else return 0;
597	}
598	if(x->ex_flags & EXFLAG_NSCERT) {
599		if(x->ex_nscert & NS_SMIME) return 1;
600		/* Workaround for some buggy certificates */
601		if(x->ex_nscert & NS_SSL_CLIENT) return 2;
602		return 0;
603	}
604	return 1;
605}
606
607static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, int ca)
608{
609	int ret;
610	ret = purpose_smime(x, ca);
611	if(!ret || ca) return ret;
612	if(ku_reject(x, KU_DIGITAL_SIGNATURE|KU_NON_REPUDIATION)) return 0;
613	return ret;
614}
615
616static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int ca)
617{
618	int ret;
619	ret = purpose_smime(x, ca);
620	if(!ret || ca) return ret;
621	if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0;
622	return ret;
623}
624
625static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int ca)
626{
627	if(ca) {
628		int ca_ret;
629		if((ca_ret = check_ca(x)) != 2) return ca_ret;
630		else return 0;
631	}
632	if(ku_reject(x, KU_CRL_SIGN)) return 0;
633	return 1;
634}
635
636/* OCSP helper: this is *not* a full OCSP check. It just checks that
637 * each CA is valid. Additional checks must be made on the chain.
638 */
639
640static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca)
641{
642	/* Must be a valid CA.  Should we really support the "I don't know"
643	   value (2)? */
644	if(ca) return check_ca(x);
645	/* leaf certificate is checked in OCSP_verify() */
646	return 1;
647}
648
649static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x,
650					int ca)
651{
652	int i_ext;
653
654	/* If ca is true we must return if this is a valid CA certificate. */
655	if (ca) return check_ca(x);
656
657	/*
658	 * Check the optional key usage field:
659	 * if Key Usage is present, it must be one of digitalSignature
660	 * and/or nonRepudiation (other values are not consistent and shall
661	 * be rejected).
662	 */
663	if ((x->ex_flags & EXFLAG_KUSAGE)
664	    && ((x->ex_kusage & ~(KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE)) ||
665		!(x->ex_kusage & (KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE))))
666		return 0;
667
668	/* Only time stamp key usage is permitted and it's required. */
669	if (!(x->ex_flags & EXFLAG_XKUSAGE) || x->ex_xkusage != XKU_TIMESTAMP)
670		return 0;
671
672	/* Extended Key Usage MUST be critical */
673	i_ext = X509_get_ext_by_NID((X509 *) x, NID_ext_key_usage, -1);
674	if (i_ext >= 0)
675		{
676		X509_EXTENSION *ext = X509_get_ext((X509 *) x, i_ext);
677		if (!X509_EXTENSION_get_critical(ext))
678			return 0;
679		}
680
681	return 1;
682}
683
684static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca)
685{
686	return 1;
687}
688
689/* Various checks to see if one certificate issued the second.
690 * This can be used to prune a set of possible issuer certificates
691 * which have been looked up using some simple method such as by
692 * subject name.
693 * These are:
694 * 1. Check issuer_name(subject) == subject_name(issuer)
695 * 2. If akid(subject) exists check it matches issuer
696 * 3. If key_usage(issuer) exists check it supports certificate signing
697 * returns 0 for OK, positive for reason for mismatch, reasons match
698 * codes for X509_verify_cert()
699 */
700
701int X509_check_issued(X509 *issuer, X509 *subject)
702{
703	if(X509_NAME_cmp(X509_get_subject_name(issuer),
704			X509_get_issuer_name(subject)))
705				return X509_V_ERR_SUBJECT_ISSUER_MISMATCH;
706	x509v3_cache_extensions(issuer);
707	x509v3_cache_extensions(subject);
708
709	if(subject->akid)
710		{
711		int ret = X509_check_akid(issuer, subject->akid);
712		if (ret != X509_V_OK)
713			return ret;
714		}
715
716	if(subject->ex_flags & EXFLAG_PROXY)
717		{
718		if(ku_reject(issuer, KU_DIGITAL_SIGNATURE))
719			return X509_V_ERR_KEYUSAGE_NO_DIGITAL_SIGNATURE;
720		}
721	else if(ku_reject(issuer, KU_KEY_CERT_SIGN))
722		return X509_V_ERR_KEYUSAGE_NO_CERTSIGN;
723	return X509_V_OK;
724}
725
726int X509_check_akid(X509 *issuer, AUTHORITY_KEYID *akid)
727	{
728
729	if(!akid)
730		return X509_V_OK;
731
732	/* Check key ids (if present) */
733	if(akid->keyid && issuer->skid &&
734		 ASN1_OCTET_STRING_cmp(akid->keyid, issuer->skid) )
735				return X509_V_ERR_AKID_SKID_MISMATCH;
736	/* Check serial number */
737	if(akid->serial &&
738		ASN1_INTEGER_cmp(X509_get_serialNumber(issuer), akid->serial))
739				return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
740	/* Check issuer name */
741	if(akid->issuer)
742		{
743		/* Ugh, for some peculiar reason AKID includes
744		 * SEQUENCE OF GeneralName. So look for a DirName.
745		 * There may be more than one but we only take any
746		 * notice of the first.
747		 */
748		GENERAL_NAMES *gens;
749		GENERAL_NAME *gen;
750		X509_NAME *nm = NULL;
751		int i;
752		gens = akid->issuer;
753		for(i = 0; i < sk_GENERAL_NAME_num(gens); i++)
754			{
755			gen = sk_GENERAL_NAME_value(gens, i);
756			if(gen->type == GEN_DIRNAME)
757				{
758				nm = gen->d.dirn;
759				break;
760				}
761			}
762		if(nm && X509_NAME_cmp(nm, X509_get_issuer_name(issuer)))
763			return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
764		}
765	return X509_V_OK;
766	}
767
768