Cleanup OPENSSL_NO_xxx, part 1
[openssl.git] / crypto / x509v3 / v3_purp.c
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
64 static void x509v3_cache_extensions(X509 *x);
65
66 static int check_ssl_ca(const X509 *x);
67 static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int ca);
68 static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca);
69 static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca);
70 static int purpose_smime(const X509 *x, int ca);
71 static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, int ca);
72 static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int ca);
73 static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int ca);
74 static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x, int ca);
75 static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca);
76 static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca);
77
78 static int xp_cmp(const X509_PURPOSE * const *a,
79                 const X509_PURPOSE * const *b);
80 static void xptable_free(X509_PURPOSE *p);
81
82 static 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
96 IMPLEMENT_STACK_OF(X509_PURPOSE)
97
98 static STACK_OF(X509_PURPOSE) *xptable = NULL;
99
100 static 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. */
109 int 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
125 int 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
135 int 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
141 X509_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
148 int 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
159 int 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
172 int 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
229 static 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
242 void 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
250 int X509_PURPOSE_get_id(X509_PURPOSE *xp)
251 {
252         return xp->purpose;
253 }
254
255 char *X509_PURPOSE_get0_name(X509_PURPOSE *xp)
256 {
257         return xp->name;
258 }
259
260 char *X509_PURPOSE_get0_sname(X509_PURPOSE *xp)
261 {
262         return xp->sname;
263 }
264
265 int X509_PURPOSE_get_trust(X509_PURPOSE *xp)
266 {
267         return xp->trust;
268 }
269
270 static int nid_cmp(const int *a, const int *b)
271         {
272         return *a - *b;
273         }
274
275 DECLARE_OBJ_BSEARCH_CMP_FN(int, int, nid);
276 IMPLEMENT_OBJ_BSEARCH_CMP_FN(int, int, nid);
277
278 int 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
317 static 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
349 static 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
357 static 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         /* V1 should mean no extensions ... */
372         if(!X509_get_version(x)) x->ex_flags |= EXFLAG_V1;
373         /* Handle basic constraints */
374         if((bs=X509_get_ext_d2i(x, NID_basic_constraints, NULL, NULL))) {
375                 if(bs->ca) x->ex_flags |= EXFLAG_CA;
376                 if(bs->pathlen) {
377                         if((bs->pathlen->type == V_ASN1_NEG_INTEGER)
378                                                 || !bs->ca) {
379                                 x->ex_flags |= EXFLAG_INVALID;
380                                 x->ex_pathlen = 0;
381                         } else x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen);
382                 } else x->ex_pathlen = -1;
383                 BASIC_CONSTRAINTS_free(bs);
384                 x->ex_flags |= EXFLAG_BCONS;
385         }
386         /* Handle proxy certificates */
387         if((pci=X509_get_ext_d2i(x, NID_proxyCertInfo, NULL, NULL))) {
388                 if (x->ex_flags & EXFLAG_CA
389                     || X509_get_ext_by_NID(x, NID_subject_alt_name, -1) >= 0
390                     || X509_get_ext_by_NID(x, NID_issuer_alt_name, -1) >= 0) {
391                         x->ex_flags |= EXFLAG_INVALID;
392                 }
393                 if (pci->pcPathLengthConstraint) {
394                         x->ex_pcpathlen =
395                                 ASN1_INTEGER_get(pci->pcPathLengthConstraint);
396                 } else x->ex_pcpathlen = -1;
397                 PROXY_CERT_INFO_EXTENSION_free(pci);
398                 x->ex_flags |= EXFLAG_PROXY;
399         }
400         /* Handle key usage */
401         if((usage=X509_get_ext_d2i(x, NID_key_usage, NULL, NULL))) {
402                 if(usage->length > 0) {
403                         x->ex_kusage = usage->data[0];
404                         if(usage->length > 1) 
405                                 x->ex_kusage |= usage->data[1] << 8;
406                 } else x->ex_kusage = 0;
407                 x->ex_flags |= EXFLAG_KUSAGE;
408                 ASN1_BIT_STRING_free(usage);
409         }
410         x->ex_xkusage = 0;
411         if((extusage=X509_get_ext_d2i(x, NID_ext_key_usage, NULL, NULL))) {
412                 x->ex_flags |= EXFLAG_XKUSAGE;
413                 for(i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) {
414                         switch(OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage,i))) {
415                                 case NID_server_auth:
416                                 x->ex_xkusage |= XKU_SSL_SERVER;
417                                 break;
418
419                                 case NID_client_auth:
420                                 x->ex_xkusage |= XKU_SSL_CLIENT;
421                                 break;
422
423                                 case NID_email_protect:
424                                 x->ex_xkusage |= XKU_SMIME;
425                                 break;
426
427                                 case NID_code_sign:
428                                 x->ex_xkusage |= XKU_CODE_SIGN;
429                                 break;
430
431                                 case NID_ms_sgc:
432                                 case NID_ns_sgc:
433                                 x->ex_xkusage |= XKU_SGC;
434                                 break;
435
436                                 case NID_OCSP_sign:
437                                 x->ex_xkusage |= XKU_OCSP_SIGN;
438                                 break;
439
440                                 case NID_time_stamp:
441                                 x->ex_xkusage |= XKU_TIMESTAMP;
442                                 break;
443
444                                 case NID_dvcs:
445                                 x->ex_xkusage |= XKU_DVCS;
446                                 break;
447
448                                 case NID_anyExtendedKeyUsage:
449                                 x->ex_xkusage |= XKU_ANYEKU;
450                                 break;
451                         }
452                 }
453                 sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free);
454         }
455
456         if((ns=X509_get_ext_d2i(x, NID_netscape_cert_type, NULL, NULL))) {
457                 if(ns->length > 0) x->ex_nscert = ns->data[0];
458                 else x->ex_nscert = 0;
459                 x->ex_flags |= EXFLAG_NSCERT;
460                 ASN1_BIT_STRING_free(ns);
461         }
462         x->skid =X509_get_ext_d2i(x, NID_subject_key_identifier, NULL, NULL);
463         x->akid =X509_get_ext_d2i(x, NID_authority_key_identifier, NULL, NULL);
464         /* Does subject name match issuer ? */
465         if(!X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x)))
466                         {
467                         x->ex_flags |= EXFLAG_SI;
468                         /* If SKID matches AKID also indicate self signed */
469                         if (X509_check_akid(x, x->akid) == X509_V_OK)
470                                 x->ex_flags |= EXFLAG_SS;
471                         }
472         x->altname = X509_get_ext_d2i(x, NID_subject_alt_name, NULL, NULL);
473         x->nc = X509_get_ext_d2i(x, NID_name_constraints, &i, NULL);
474         if (!x->nc && (i != -1))
475                 x->ex_flags |= EXFLAG_INVALID;
476         setup_crldp(x);
477
478 #ifndef OPENSSL_NO_RFC3779
479         x->rfc3779_addr =X509_get_ext_d2i(x, NID_sbgp_ipAddrBlock, NULL, NULL);
480         x->rfc3779_asid =X509_get_ext_d2i(x, NID_sbgp_autonomousSysNum,
481                                           NULL, NULL);
482 #endif
483         for (i = 0; i < X509_get_ext_count(x); i++)
484                 {
485                 ex = X509_get_ext(x, i);
486                 if (OBJ_obj2nid(X509_EXTENSION_get_object(ex))
487                                         == NID_freshest_crl)
488                         x->ex_flags |= EXFLAG_FRESHEST;
489                 if (!X509_EXTENSION_get_critical(ex))
490                         continue;
491                 if (!X509_supported_extension(ex))
492                         {
493                         x->ex_flags |= EXFLAG_CRITICAL;
494                         break;
495                         }
496                 }
497         x->ex_flags |= EXFLAG_SET;
498 }
499
500 /*-
501  * CA checks common to all purposes
502  * return codes:
503  * 0 not a CA
504  * 1 is a CA
505  * 2 basicConstraints absent so "maybe" a CA
506  * 3 basicConstraints absent but self signed V1.
507  * 4 basicConstraints absent but keyUsage present and keyCertSign asserted.
508  */
509
510 #define V1_ROOT (EXFLAG_V1|EXFLAG_SS)
511 #define ku_reject(x, usage) \
512         (((x)->ex_flags & EXFLAG_KUSAGE) && !((x)->ex_kusage & (usage)))
513 #define xku_reject(x, usage) \
514         (((x)->ex_flags & EXFLAG_XKUSAGE) && !((x)->ex_xkusage & (usage)))
515 #define ns_reject(x, usage) \
516         (((x)->ex_flags & EXFLAG_NSCERT) && !((x)->ex_nscert & (usage)))
517
518 static int check_ca(const X509 *x)
519 {
520         /* keyUsage if present should allow cert signing */
521         if(ku_reject(x, KU_KEY_CERT_SIGN)) return 0;
522         if(x->ex_flags & EXFLAG_BCONS) {
523                 if(x->ex_flags & EXFLAG_CA) return 1;
524                 /* If basicConstraints says not a CA then say so */
525                 else return 0;
526         } else {
527                 /* we support V1 roots for...  uh, I don't really know why. */
528                 if((x->ex_flags & V1_ROOT) == V1_ROOT) return 3;
529                 /* If key usage present it must have certSign so tolerate it */
530                 else if (x->ex_flags & EXFLAG_KUSAGE) return 4;
531                 /* Older certificates could have Netscape-specific CA types */
532                 else if (x->ex_flags & EXFLAG_NSCERT
533                          && x->ex_nscert & NS_ANY_CA) return 5;
534                 /* can this still be regarded a CA certificate?  I doubt it */
535                 return 0;
536         }
537 }
538
539 int X509_check_ca(X509 *x)
540 {
541         if(!(x->ex_flags & EXFLAG_SET)) {
542                 CRYPTO_w_lock(CRYPTO_LOCK_X509);
543                 x509v3_cache_extensions(x);
544                 CRYPTO_w_unlock(CRYPTO_LOCK_X509);
545         }
546
547         return check_ca(x);
548 }
549
550 /* Check SSL CA: common checks for SSL client and server */
551 static int check_ssl_ca(const X509 *x)
552 {
553         int ca_ret;
554         ca_ret = check_ca(x);
555         if(!ca_ret) return 0;
556         /* check nsCertType if present */
557         if(ca_ret != 5 || x->ex_nscert & NS_SSL_CA) return ca_ret;
558         else return 0;
559 }
560
561
562 static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int ca)
563 {
564         if(xku_reject(x,XKU_SSL_CLIENT)) return 0;
565         if(ca) return check_ssl_ca(x);
566         /* We need to do digital signatures or key agreement */
567         if(ku_reject(x,KU_DIGITAL_SIGNATURE|KU_KEY_AGREEMENT)) return 0;
568         /* nsCertType if present should allow SSL client use */ 
569         if(ns_reject(x, NS_SSL_CLIENT)) return 0;
570         return 1;
571 }
572 /* Key usage needed for TLS/SSL server: digital signature, encipherment or
573  * key agreement. The ssl code can check this more thoroughly for individual
574  * key types.
575  */
576 #define KU_TLS \
577         KU_DIGITAL_SIGNATURE|KU_KEY_ENCIPHERMENT|KU_KEY_AGREEMENT
578
579 static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca)
580 {
581         if(xku_reject(x,XKU_SSL_SERVER|XKU_SGC)) return 0;
582         if(ca) return check_ssl_ca(x);
583
584         if(ns_reject(x, NS_SSL_SERVER)) return 0;
585         if(ku_reject(x, KU_TLS)) return 0;
586         
587         return 1;
588
589 }
590
591 static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca)
592 {
593         int ret;
594         ret = check_purpose_ssl_server(xp, x, ca);
595         if(!ret || ca) return ret;
596         /* We need to encipher or Netscape complains */
597         if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0;
598         return ret;
599 }
600
601 /* common S/MIME checks */
602 static int purpose_smime(const X509 *x, int ca)
603 {
604         if(xku_reject(x,XKU_SMIME)) return 0;
605         if(ca) {
606                 int ca_ret;
607                 ca_ret = check_ca(x);
608                 if(!ca_ret) return 0;
609                 /* check nsCertType if present */
610                 if(ca_ret != 5 || x->ex_nscert & NS_SMIME_CA) return ca_ret;
611                 else return 0;
612         }
613         if(x->ex_flags & EXFLAG_NSCERT) {
614                 if(x->ex_nscert & NS_SMIME) return 1;
615                 /* Workaround for some buggy certificates */
616                 if(x->ex_nscert & NS_SSL_CLIENT) return 2;
617                 return 0;
618         }
619         return 1;
620 }
621
622 static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, int ca)
623 {
624         int ret;
625         ret = purpose_smime(x, ca);
626         if(!ret || ca) return ret;
627         if(ku_reject(x, KU_DIGITAL_SIGNATURE|KU_NON_REPUDIATION)) return 0;
628         return ret;
629 }
630
631 static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int ca)
632 {
633         int ret;
634         ret = purpose_smime(x, ca);
635         if(!ret || ca) return ret;
636         if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0;
637         return ret;
638 }
639
640 static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int ca)
641 {
642         if(ca) {
643                 int ca_ret;
644                 if((ca_ret = check_ca(x)) != 2) return ca_ret;
645                 else return 0;
646         }
647         if(ku_reject(x, KU_CRL_SIGN)) return 0;
648         return 1;
649 }
650
651 /* OCSP helper: this is *not* a full OCSP check. It just checks that
652  * each CA is valid. Additional checks must be made on the chain.
653  */
654
655 static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca)
656 {
657         /* Must be a valid CA.  Should we really support the "I don't know"
658            value (2)? */
659         if(ca) return check_ca(x);
660         /* leaf certificate is checked in OCSP_verify() */
661         return 1;
662 }
663
664 static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x,
665                                         int ca)
666 {
667         int i_ext;
668
669         /* If ca is true we must return if this is a valid CA certificate. */
670         if (ca) return check_ca(x);
671
672         /* 
673          * Check the optional key usage field:
674          * if Key Usage is present, it must be one of digitalSignature 
675          * and/or nonRepudiation (other values are not consistent and shall
676          * be rejected).
677          */
678         if ((x->ex_flags & EXFLAG_KUSAGE)
679             && ((x->ex_kusage & ~(KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE)) ||
680                 !(x->ex_kusage & (KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE))))
681                 return 0;
682
683         /* Only time stamp key usage is permitted and it's required. */
684         if (!(x->ex_flags & EXFLAG_XKUSAGE) || x->ex_xkusage != XKU_TIMESTAMP)
685                 return 0;
686
687         /* Extended Key Usage MUST be critical */
688         i_ext = X509_get_ext_by_NID((X509 *) x, NID_ext_key_usage, -1);
689         if (i_ext >= 0)
690                 {
691                 X509_EXTENSION *ext = X509_get_ext((X509 *) x, i_ext);
692                 if (!X509_EXTENSION_get_critical(ext))
693                         return 0;
694                 }
695
696         return 1;
697 }
698
699 static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca)
700 {
701         return 1;
702 }
703
704 /*-
705  * Various checks to see if one certificate issued the second.
706  * This can be used to prune a set of possible issuer certificates
707  * which have been looked up using some simple method such as by
708  * subject name.
709  * These are:
710  * 1. Check issuer_name(subject) == subject_name(issuer)
711  * 2. If akid(subject) exists check it matches issuer
712  * 3. If key_usage(issuer) exists check it supports certificate signing
713  * returns 0 for OK, positive for reason for mismatch, reasons match
714  * codes for X509_verify_cert()
715  */
716
717 int X509_check_issued(X509 *issuer, X509 *subject)
718 {
719         if(X509_NAME_cmp(X509_get_subject_name(issuer),
720                         X509_get_issuer_name(subject)))
721                                 return X509_V_ERR_SUBJECT_ISSUER_MISMATCH;
722         x509v3_cache_extensions(issuer);
723         x509v3_cache_extensions(subject);
724
725         if(subject->akid)
726                 {
727                 int ret = X509_check_akid(issuer, subject->akid);
728                 if (ret != X509_V_OK)
729                         return ret;
730                 }
731
732         if(subject->ex_flags & EXFLAG_PROXY)
733                 {
734                 if(ku_reject(issuer, KU_DIGITAL_SIGNATURE))
735                         return X509_V_ERR_KEYUSAGE_NO_DIGITAL_SIGNATURE;
736                 }
737         else if(ku_reject(issuer, KU_KEY_CERT_SIGN))
738                 return X509_V_ERR_KEYUSAGE_NO_CERTSIGN;
739         return X509_V_OK;
740 }
741
742 int X509_check_akid(X509 *issuer, AUTHORITY_KEYID *akid)
743         {
744
745         if(!akid)
746                 return X509_V_OK;
747
748         /* Check key ids (if present) */
749         if(akid->keyid && issuer->skid &&
750                  ASN1_OCTET_STRING_cmp(akid->keyid, issuer->skid) )
751                                 return X509_V_ERR_AKID_SKID_MISMATCH;
752         /* Check serial number */
753         if(akid->serial &&
754                 ASN1_INTEGER_cmp(X509_get_serialNumber(issuer), akid->serial))
755                                 return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
756         /* Check issuer name */
757         if(akid->issuer)
758                 {
759                 /* Ugh, for some peculiar reason AKID includes
760                  * SEQUENCE OF GeneralName. So look for a DirName.
761                  * There may be more than one but we only take any
762                  * notice of the first.
763                  */
764                 GENERAL_NAMES *gens;
765                 GENERAL_NAME *gen;
766                 X509_NAME *nm = NULL;
767                 int i;
768                 gens = akid->issuer;
769                 for(i = 0; i < sk_GENERAL_NAME_num(gens); i++)
770                         {
771                         gen = sk_GENERAL_NAME_value(gens, i);
772                         if(gen->type == GEN_DIRNAME)
773                                 {
774                                 nm = gen->d.dirn;
775                                 break;
776                                 }
777                         }
778                 if(nm && X509_NAME_cmp(nm, X509_get_issuer_name(issuer)))
779                         return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
780                 }
781         return X509_V_OK;
782         }
783