v3_purp.c revision 127128
1/* v3_purp.c */
2/* Written by Dr Stephen N Henson (shenson@bigfoot.com) 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 ca_check(const X509 *x);
67static int check_ssl_ca(const X509 *x);
68static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int ca);
69static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca);
70static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca);
71static int purpose_smime(const X509 *x, int ca);
72static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, int ca);
73static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int ca);
74static int check_purpose_crl_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};
92
93#define X509_PURPOSE_COUNT (sizeof(xstandard)/sizeof(X509_PURPOSE))
94
95IMPLEMENT_STACK_OF(X509_PURPOSE)
96
97static STACK_OF(X509_PURPOSE) *xptable = NULL;
98
99static int xp_cmp(const X509_PURPOSE * const *a,
100		const X509_PURPOSE * const *b)
101{
102	return (*a)->purpose - (*b)->purpose;
103}
104
105/* As much as I'd like to make X509_check_purpose use a "const" X509*
106 * I really can't because it does recalculate hashes and do other non-const
107 * things. */
108int X509_check_purpose(X509 *x, int id, int ca)
109{
110	int idx;
111	const X509_PURPOSE *pt;
112	if(!(x->ex_flags & EXFLAG_SET)) {
113		CRYPTO_w_lock(CRYPTO_LOCK_X509);
114		x509v3_cache_extensions(x);
115		CRYPTO_w_unlock(CRYPTO_LOCK_X509);
116	}
117	if(id == -1) return 1;
118	idx = X509_PURPOSE_get_by_id(id);
119	if(idx == -1) return -1;
120	pt = X509_PURPOSE_get0(idx);
121	return pt->check_purpose(pt, x, ca);
122}
123
124int X509_PURPOSE_set(int *p, int purpose)
125{
126	if(X509_PURPOSE_get_by_id(purpose) == -1) {
127		X509V3err(X509V3_F_X509_PURPOSE_SET, X509V3_R_INVALID_PURPOSE);
128		return 0;
129	}
130	*p = purpose;
131	return 1;
132}
133
134int X509_PURPOSE_get_count(void)
135{
136	if(!xptable) return X509_PURPOSE_COUNT;
137	return sk_X509_PURPOSE_num(xptable) + X509_PURPOSE_COUNT;
138}
139
140X509_PURPOSE * X509_PURPOSE_get0(int idx)
141{
142	if(idx < 0) return NULL;
143	if(idx < X509_PURPOSE_COUNT) return xstandard + idx;
144	return sk_X509_PURPOSE_value(xptable, idx - X509_PURPOSE_COUNT);
145}
146
147int X509_PURPOSE_get_by_sname(char *sname)
148{
149	int i;
150	X509_PURPOSE *xptmp;
151	for(i = 0; i < X509_PURPOSE_get_count(); i++) {
152		xptmp = X509_PURPOSE_get0(i);
153		if(!strcmp(xptmp->sname, sname)) return i;
154	}
155	return -1;
156}
157
158int X509_PURPOSE_get_by_id(int purpose)
159{
160	X509_PURPOSE tmp;
161	int idx;
162	if((purpose >= X509_PURPOSE_MIN) && (purpose <= X509_PURPOSE_MAX))
163		return purpose - X509_PURPOSE_MIN;
164	tmp.purpose = purpose;
165	if(!xptable) return -1;
166	idx = sk_X509_PURPOSE_find(xptable, &tmp);
167	if(idx == -1) return -1;
168	return idx + X509_PURPOSE_COUNT;
169}
170
171int X509_PURPOSE_add(int id, int trust, int flags,
172			int (*ck)(const X509_PURPOSE *, const X509 *, int),
173					char *name, char *sname, void *arg)
174{
175	int idx;
176	X509_PURPOSE *ptmp;
177	/* This is set according to what we change: application can't set it */
178	flags &= ~X509_PURPOSE_DYNAMIC;
179	/* This will always be set for application modified trust entries */
180	flags |= X509_PURPOSE_DYNAMIC_NAME;
181	/* Get existing entry if any */
182	idx = X509_PURPOSE_get_by_id(id);
183	/* Need a new entry */
184	if(idx == -1) {
185		if(!(ptmp = OPENSSL_malloc(sizeof(X509_PURPOSE)))) {
186			X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
187			return 0;
188		}
189		ptmp->flags = X509_PURPOSE_DYNAMIC;
190	} else ptmp = X509_PURPOSE_get0(idx);
191
192	/* OPENSSL_free existing name if dynamic */
193	if(ptmp->flags & X509_PURPOSE_DYNAMIC_NAME) {
194		OPENSSL_free(ptmp->name);
195		OPENSSL_free(ptmp->sname);
196	}
197	/* dup supplied name */
198	ptmp->name = BUF_strdup(name);
199	ptmp->sname = BUF_strdup(sname);
200	if(!ptmp->name || !ptmp->sname) {
201		X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
202		return 0;
203	}
204	/* Keep the dynamic flag of existing entry */
205	ptmp->flags &= X509_PURPOSE_DYNAMIC;
206	/* Set all other flags */
207	ptmp->flags |= flags;
208
209	ptmp->purpose = id;
210	ptmp->trust = trust;
211	ptmp->check_purpose = ck;
212	ptmp->usr_data = arg;
213
214	/* If its a new entry manage the dynamic table */
215	if(idx == -1) {
216		if(!xptable && !(xptable = sk_X509_PURPOSE_new(xp_cmp))) {
217			X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
218			return 0;
219		}
220		if (!sk_X509_PURPOSE_push(xptable, ptmp)) {
221			X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
222			return 0;
223		}
224	}
225	return 1;
226}
227
228static void xptable_free(X509_PURPOSE *p)
229	{
230	if(!p) return;
231	if (p->flags & X509_PURPOSE_DYNAMIC)
232		{
233		if (p->flags & X509_PURPOSE_DYNAMIC_NAME) {
234			OPENSSL_free(p->name);
235			OPENSSL_free(p->sname);
236		}
237		OPENSSL_free(p);
238		}
239	}
240
241void X509_PURPOSE_cleanup(void)
242{
243	int i;
244	sk_X509_PURPOSE_pop_free(xptable, xptable_free);
245	for(i = 0; i < X509_PURPOSE_COUNT; i++) xptable_free(xstandard + i);
246	xptable = NULL;
247}
248
249int X509_PURPOSE_get_id(X509_PURPOSE *xp)
250{
251	return xp->purpose;
252}
253
254char *X509_PURPOSE_get0_name(X509_PURPOSE *xp)
255{
256	return xp->name;
257}
258
259char *X509_PURPOSE_get0_sname(X509_PURPOSE *xp)
260{
261	return xp->sname;
262}
263
264int X509_PURPOSE_get_trust(X509_PURPOSE *xp)
265{
266	return xp->trust;
267}
268
269static int nid_cmp(int *a, int *b)
270	{
271	return *a - *b;
272	}
273
274int X509_supported_extension(X509_EXTENSION *ex)
275	{
276	/* This table is a list of the NIDs of supported extensions:
277	 * that is those which are used by the verify process. If
278	 * an extension is critical and doesn't appear in this list
279	 * then the verify process will normally reject the certificate.
280	 * The list must be kept in numerical order because it will be
281	 * searched using bsearch.
282	 */
283
284	static int supported_nids[] = {
285		NID_netscape_cert_type, /* 71 */
286        	NID_key_usage,		/* 83 */
287		NID_subject_alt_name,	/* 85 */
288		NID_basic_constraints,	/* 87 */
289        	NID_ext_key_usage	/* 126 */
290	};
291
292	int ex_nid;
293
294	ex_nid = OBJ_obj2nid(X509_EXTENSION_get_object(ex));
295
296	if (ex_nid == NID_undef)
297		return 0;
298
299	if (OBJ_bsearch((char *)&ex_nid, (char *)supported_nids,
300		sizeof(supported_nids)/sizeof(int), sizeof(int),
301		(int (*)(const void *, const void *))nid_cmp))
302		return 1;
303	return 0;
304	}
305
306
307static void x509v3_cache_extensions(X509 *x)
308{
309	BASIC_CONSTRAINTS *bs;
310	ASN1_BIT_STRING *usage;
311	ASN1_BIT_STRING *ns;
312	EXTENDED_KEY_USAGE *extusage;
313	X509_EXTENSION *ex;
314
315	int i;
316	if(x->ex_flags & EXFLAG_SET) return;
317#ifndef OPENSSL_NO_SHA
318	X509_digest(x, EVP_sha1(), x->sha1_hash, NULL);
319#endif
320	/* Does subject name match issuer ? */
321	if(!X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x)))
322			 x->ex_flags |= EXFLAG_SS;
323	/* V1 should mean no extensions ... */
324	if(!X509_get_version(x)) x->ex_flags |= EXFLAG_V1;
325	/* Handle basic constraints */
326	if((bs=X509_get_ext_d2i(x, NID_basic_constraints, NULL, NULL))) {
327		if(bs->ca) x->ex_flags |= EXFLAG_CA;
328		if(bs->pathlen) {
329			if((bs->pathlen->type == V_ASN1_NEG_INTEGER)
330						|| !bs->ca) {
331				x->ex_flags |= EXFLAG_INVALID;
332				x->ex_pathlen = 0;
333			} else x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen);
334		} else x->ex_pathlen = -1;
335		BASIC_CONSTRAINTS_free(bs);
336		x->ex_flags |= EXFLAG_BCONS;
337	}
338	/* Handle key usage */
339	if((usage=X509_get_ext_d2i(x, NID_key_usage, NULL, NULL))) {
340		if(usage->length > 0) {
341			x->ex_kusage = usage->data[0];
342			if(usage->length > 1)
343				x->ex_kusage |= usage->data[1] << 8;
344		} else x->ex_kusage = 0;
345		x->ex_flags |= EXFLAG_KUSAGE;
346		ASN1_BIT_STRING_free(usage);
347	}
348	x->ex_xkusage = 0;
349	if((extusage=X509_get_ext_d2i(x, NID_ext_key_usage, NULL, NULL))) {
350		x->ex_flags |= EXFLAG_XKUSAGE;
351		for(i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) {
352			switch(OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage,i))) {
353				case NID_server_auth:
354				x->ex_xkusage |= XKU_SSL_SERVER;
355				break;
356
357				case NID_client_auth:
358				x->ex_xkusage |= XKU_SSL_CLIENT;
359				break;
360
361				case NID_email_protect:
362				x->ex_xkusage |= XKU_SMIME;
363				break;
364
365				case NID_code_sign:
366				x->ex_xkusage |= XKU_CODE_SIGN;
367				break;
368
369				case NID_ms_sgc:
370				case NID_ns_sgc:
371				x->ex_xkusage |= XKU_SGC;
372				break;
373
374				case NID_OCSP_sign:
375				x->ex_xkusage |= XKU_OCSP_SIGN;
376				break;
377
378				case NID_time_stamp:
379				x->ex_xkusage |= XKU_TIMESTAMP;
380				break;
381
382				case NID_dvcs:
383				x->ex_xkusage |= XKU_DVCS;
384				break;
385			}
386		}
387		sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free);
388	}
389
390	if((ns=X509_get_ext_d2i(x, NID_netscape_cert_type, NULL, NULL))) {
391		if(ns->length > 0) x->ex_nscert = ns->data[0];
392		else x->ex_nscert = 0;
393		x->ex_flags |= EXFLAG_NSCERT;
394		ASN1_BIT_STRING_free(ns);
395	}
396	x->skid =X509_get_ext_d2i(x, NID_subject_key_identifier, NULL, NULL);
397	x->akid =X509_get_ext_d2i(x, NID_authority_key_identifier, NULL, NULL);
398	for (i = 0; i < X509_get_ext_count(x); i++)
399		{
400		ex = X509_get_ext(x, i);
401		if (!X509_EXTENSION_get_critical(ex))
402			continue;
403		if (!X509_supported_extension(ex))
404			{
405			x->ex_flags |= EXFLAG_CRITICAL;
406			break;
407			}
408		}
409	x->ex_flags |= EXFLAG_SET;
410}
411
412/* CA checks common to all purposes
413 * return codes:
414 * 0 not a CA
415 * 1 is a CA
416 * 2 basicConstraints absent so "maybe" a CA
417 * 3 basicConstraints absent but self signed V1.
418 * 4 basicConstraints absent but keyUsage present and keyCertSign asserted.
419 */
420
421#define V1_ROOT (EXFLAG_V1|EXFLAG_SS)
422#define ku_reject(x, usage) \
423	(((x)->ex_flags & EXFLAG_KUSAGE) && !((x)->ex_kusage & (usage)))
424#define xku_reject(x, usage) \
425	(((x)->ex_flags & EXFLAG_XKUSAGE) && !((x)->ex_xkusage & (usage)))
426#define ns_reject(x, usage) \
427	(((x)->ex_flags & EXFLAG_NSCERT) && !((x)->ex_nscert & (usage)))
428
429static int ca_check(const X509 *x)
430{
431	/* keyUsage if present should allow cert signing */
432	if(ku_reject(x, KU_KEY_CERT_SIGN)) return 0;
433	if(x->ex_flags & EXFLAG_BCONS) {
434		if(x->ex_flags & EXFLAG_CA) return 1;
435		/* If basicConstraints says not a CA then say so */
436		else return 0;
437	} else {
438		if((x->ex_flags & V1_ROOT) == V1_ROOT) return 3;
439		/* If key usage present it must have certSign so tolerate it */
440		else if (x->ex_flags & EXFLAG_KUSAGE) return 4;
441		else return 2;
442	}
443}
444
445/* Check SSL CA: common checks for SSL client and server */
446static int check_ssl_ca(const X509 *x)
447{
448	int ca_ret;
449	ca_ret = ca_check(x);
450	if(!ca_ret) return 0;
451	/* check nsCertType if present */
452	if(x->ex_flags & EXFLAG_NSCERT) {
453		if(x->ex_nscert & NS_SSL_CA) return ca_ret;
454		return 0;
455	}
456	if(ca_ret != 2) return ca_ret;
457	else return 0;
458}
459
460
461static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int ca)
462{
463	if(xku_reject(x,XKU_SSL_CLIENT)) return 0;
464	if(ca) return check_ssl_ca(x);
465	/* We need to do digital signatures with it */
466	if(ku_reject(x,KU_DIGITAL_SIGNATURE)) return 0;
467	/* nsCertType if present should allow SSL client use */
468	if(ns_reject(x, NS_SSL_CLIENT)) return 0;
469	return 1;
470}
471
472static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca)
473{
474	if(xku_reject(x,XKU_SSL_SERVER|XKU_SGC)) return 0;
475	if(ca) return check_ssl_ca(x);
476
477	if(ns_reject(x, NS_SSL_SERVER)) return 0;
478	/* Now as for keyUsage: we'll at least need to sign OR encipher */
479	if(ku_reject(x, KU_DIGITAL_SIGNATURE|KU_KEY_ENCIPHERMENT)) return 0;
480
481	return 1;
482
483}
484
485static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca)
486{
487	int ret;
488	ret = check_purpose_ssl_server(xp, x, ca);
489	if(!ret || ca) return ret;
490	/* We need to encipher or Netscape complains */
491	if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0;
492	return ret;
493}
494
495/* common S/MIME checks */
496static int purpose_smime(const X509 *x, int ca)
497{
498	if(xku_reject(x,XKU_SMIME)) return 0;
499	if(ca) {
500		int ca_ret;
501		ca_ret = ca_check(x);
502		if(!ca_ret) return 0;
503		/* check nsCertType if present */
504		if(x->ex_flags & EXFLAG_NSCERT) {
505			if(x->ex_nscert & NS_SMIME_CA) return ca_ret;
506			return 0;
507		}
508		if(ca_ret != 2) return ca_ret;
509		else return 0;
510	}
511	if(x->ex_flags & EXFLAG_NSCERT) {
512		if(x->ex_nscert & NS_SMIME) return 1;
513		/* Workaround for some buggy certificates */
514		if(x->ex_nscert & NS_SSL_CLIENT) return 2;
515		return 0;
516	}
517	return 1;
518}
519
520static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, int ca)
521{
522	int ret;
523	ret = purpose_smime(x, ca);
524	if(!ret || ca) return ret;
525	if(ku_reject(x, KU_DIGITAL_SIGNATURE|KU_NON_REPUDIATION)) return 0;
526	return ret;
527}
528
529static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int ca)
530{
531	int ret;
532	ret = purpose_smime(x, ca);
533	if(!ret || ca) return ret;
534	if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0;
535	return ret;
536}
537
538static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int ca)
539{
540	if(ca) {
541		int ca_ret;
542		if((ca_ret = ca_check(x)) != 2) return ca_ret;
543		else return 0;
544	}
545	if(ku_reject(x, KU_CRL_SIGN)) return 0;
546	return 1;
547}
548
549/* OCSP helper: this is *not* a full OCSP check. It just checks that
550 * each CA is valid. Additional checks must be made on the chain.
551 */
552
553static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca)
554{
555	/* Must be a valid CA */
556	if(ca) {
557		int ca_ret;
558		ca_ret = ca_check(x);
559		if(ca_ret != 2) return ca_ret;
560		if(x->ex_flags & EXFLAG_NSCERT) {
561			if(x->ex_nscert & NS_ANY_CA) return ca_ret;
562			return 0;
563		}
564		return 0;
565	}
566	/* leaf certificate is checked in OCSP_verify() */
567	return 1;
568}
569
570static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca)
571{
572	return 1;
573}
574
575/* Various checks to see if one certificate issued the second.
576 * This can be used to prune a set of possible issuer certificates
577 * which have been looked up using some simple method such as by
578 * subject name.
579 * These are:
580 * 1. Check issuer_name(subject) == subject_name(issuer)
581 * 2. If akid(subject) exists check it matches issuer
582 * 3. If key_usage(issuer) exists check it supports certificate signing
583 * returns 0 for OK, positive for reason for mismatch, reasons match
584 * codes for X509_verify_cert()
585 */
586
587int X509_check_issued(X509 *issuer, X509 *subject)
588{
589	if(X509_NAME_cmp(X509_get_subject_name(issuer),
590			X509_get_issuer_name(subject)))
591				return X509_V_ERR_SUBJECT_ISSUER_MISMATCH;
592	x509v3_cache_extensions(issuer);
593	x509v3_cache_extensions(subject);
594	if(subject->akid) {
595		/* Check key ids (if present) */
596		if(subject->akid->keyid && issuer->skid &&
597		 ASN1_OCTET_STRING_cmp(subject->akid->keyid, issuer->skid) )
598				return X509_V_ERR_AKID_SKID_MISMATCH;
599		/* Check serial number */
600		if(subject->akid->serial &&
601			ASN1_INTEGER_cmp(X509_get_serialNumber(issuer),
602						subject->akid->serial))
603				return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
604		/* Check issuer name */
605		if(subject->akid->issuer) {
606			/* Ugh, for some peculiar reason AKID includes
607			 * SEQUENCE OF GeneralName. So look for a DirName.
608			 * There may be more than one but we only take any
609			 * notice of the first.
610			 */
611			GENERAL_NAMES *gens;
612			GENERAL_NAME *gen;
613			X509_NAME *nm = NULL;
614			int i;
615			gens = subject->akid->issuer;
616			for(i = 0; i < sk_GENERAL_NAME_num(gens); i++) {
617				gen = sk_GENERAL_NAME_value(gens, i);
618				if(gen->type == GEN_DIRNAME) {
619					nm = gen->d.dirn;
620					break;
621				}
622			}
623			if(nm && X509_NAME_cmp(nm, X509_get_issuer_name(issuer)))
624				return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
625		}
626	}
627	if(ku_reject(issuer, KU_KEY_CERT_SIGN)) return X509_V_ERR_KEYUSAGE_NO_CERTSIGN;
628	return X509_V_OK;
629}
630
631