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[openssl.git] / crypto / x509v3 / v3_purp.c
1 /* v3_purp.c */
2 /* Written by Dr Stephen N Henson (shenson@bigfoot.com) 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 "cryptlib.h"
61 #include <openssl/x509v3.h>
62
63
64 static int x509_purpose_get_idx(int id);
65 static void x509v3_cache_extensions(X509 *x);
66
67 static int ca_check(X509 *x);
68 static int check_purpose_ssl_client(X509_PURPOSE *xp, X509 *x, int ca);
69 static int check_purpose_ssl_server(X509_PURPOSE *xp, X509 *x, int ca);
70 static int check_purpose_ns_ssl_server(X509_PURPOSE *xp, X509 *x, int ca);
71 static int purpose_smime(X509 *x, int ca);
72 static int check_purpose_smime_sign(X509_PURPOSE *xp, X509 *x, int ca);
73 static int check_purpose_smime_encrypt(X509_PURPOSE *xp, X509 *x, int ca);
74 static int check_purpose_crl_sign(X509_PURPOSE *xp, X509 *x, int ca);
75
76 static int xp_cmp(X509_PURPOSE **a, X509_PURPOSE **b);
77
78 static X509_PURPOSE xstandard[] = {
79         {1, 0, check_purpose_ssl_client, "SSL client", /* NULL */},
80         {2, 0, check_purpose_ssl_server, "SSL server", /* NULL */},
81         {3, 0, check_purpose_ns_ssl_server, "Netscape SSL server", /* NULL */},
82         {4, 0, check_purpose_smime_sign, "S/MIME signing", /* NULL */},
83         {5, 0, check_purpose_smime_encrypt, "S/MIME encryption", /* NULL */},
84         {6, 0, check_purpose_crl_sign, "CRL signing", /* NULL */},
85         {-1, 0, NULL, NULL, /* NULL */}
86 };
87
88 IMPLEMENT_STACK_OF(X509_PURPOSE)
89
90 static STACK_OF(X509_PURPOSE) *xptable = NULL;
91
92 static int xp_cmp(X509_PURPOSE **a, X509_PURPOSE **b)
93 {
94         return (*a)->purpose_id - (*b)->purpose_id;
95 }
96
97 int X509_check_purpose(X509 *x, int id, int ca)
98 {
99         int idx;
100         X509_PURPOSE *pt;
101         if(!(x->ex_flags & EXFLAG_SET)) {
102                 CRYPTO_w_lock(CRYPTO_LOCK_X509);
103                 x509v3_cache_extensions(x);
104                 CRYPTO_w_unlock(CRYPTO_LOCK_X509);
105         }
106         idx = x509_purpose_get_idx(id);
107         if(idx == -1) return -1;
108         pt = sk_X509_PURPOSE_value(xptable, idx);
109         return pt->check_purpose(pt, x,ca);
110 }
111                         
112
113
114
115 static int x509_purpose_get_idx(int id)
116 {
117         X509_PURPOSE tmp;
118         tmp.purpose_id = id;
119         if(!xptable) return -1;
120         return sk_X509_PURPOSE_find(xptable, &tmp);
121 }
122
123 int X509_PURPOSE_add(X509_PURPOSE *xp)
124 {
125         int idx;
126         if(!xptable)
127                 {
128                 xptable = sk_X509_PURPOSE_new(xp_cmp);
129                 if (!xptable) 
130                         {
131                         X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
132                         return 0;
133                         }
134                 }
135                         
136         idx = x509_purpose_get_idx(xp->purpose_id);
137         if(idx != -1)
138                 sk_X509_PURPOSE_set(xptable, idx, xp);
139         else
140                 if (!sk_X509_PURPOSE_push(xptable, xp))
141                         {
142                         X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
143                         return 0;
144                         }
145         return 1;
146 }
147
148 static void xptable_free(X509_PURPOSE *p)
149         {
150         if (p->purpose_flags & X509_PURPOSE_DYNAMIC) 
151                 {
152                 if (p->purpose_flags & X509_PURPOSE_DYNAMIC_NAME)
153                         Free(p->purpose_name);
154                 Free(p);
155                 }
156         }
157
158 void X509_PURPOSE_cleanup(void)
159 {
160         sk_X509_PURPOSE_pop_free(xptable, xptable_free);
161         xptable = NULL;
162 }
163
164 void X509_PURPOSE_add_standard(void)
165 {
166         X509_PURPOSE *xp;
167         for(xp = xstandard; xp->purpose_name; xp++)
168                 X509_PURPOSE_add(xp);
169 }
170
171 int X509_PURPOSE_enum(int (*efunc)(X509_PURPOSE *, void *), void *usr)
172 {
173         int i;
174         X509_PURPOSE *xp;
175         if(!xptable) return 0;
176         for(i = 0; i < sk_X509_PURPOSE_num(xptable); i++) {
177                 xp = sk_X509_PURPOSE_value(xptable, i);
178                 if(!efunc(xp, usr)) return i;
179         }
180         return i;
181 }
182
183
184 int X509_PURPOSE_get_id(X509_PURPOSE *xp)
185 {
186         return xp->purpose_id;
187 }
188
189 char *X509_PURPOSE_get_name(X509_PURPOSE *xp)
190 {
191         return xp->purpose_name;
192 }
193
194 static void x509v3_cache_extensions(X509 *x)
195 {
196         BASIC_CONSTRAINTS *bs;
197         ASN1_BIT_STRING *usage;
198         ASN1_BIT_STRING *ns;
199         STACK_OF(ASN1_OBJECT) *extusage;
200         int i;
201         if(x->ex_flags & EXFLAG_SET) return;
202         /* Does subject name match issuer ? */
203         if(X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x)))
204                          x->ex_flags |= EXFLAG_SS;
205         /* V1 should mean no extensions ... */
206         if(!X509_get_version(x)) x->ex_flags |= EXFLAG_V1;
207         /* Handle basic constraints */
208         if((bs=X509V3_X509_get_d2i(x, NID_basic_constraints, NULL, NULL))) {
209                 if(bs->ca) x->ex_flags |= EXFLAG_CA;
210                 if(bs->pathlen) {
211                         if((bs->pathlen->type == V_ASN1_NEG_INTEGER)
212                                                 || !bs->ca) {
213                                 x->ex_flags |= EXFLAG_INVALID;
214                                 x->ex_pathlen = 0;
215                         } else x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen);
216                 } else x->ex_pathlen = -1;
217                 BASIC_CONSTRAINTS_free(bs);
218                 x->ex_flags |= EXFLAG_BCONS;
219         }
220         /* Handle key usage */
221         if((usage=X509V3_X509_get_d2i(x, NID_key_usage, NULL, NULL))) {
222                 if(usage->length > 0) {
223                         x->ex_kusage = usage->data[0];
224                         if(usage->length > 1) 
225                                 x->ex_kusage |= usage->data[1] << 8;
226                 } else x->ex_kusage = 0;
227                 x->ex_flags |= EXFLAG_KUSAGE;
228                 ASN1_BIT_STRING_free(usage);
229         }
230         x->ex_xkusage = 0;
231         if((extusage=X509V3_X509_get_d2i(x, NID_ext_key_usage, NULL, NULL))) {
232                 x->ex_flags |= EXFLAG_XKUSAGE;
233                 for(i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) {
234                         switch(OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage,i))) {
235                                 case NID_server_auth:
236                                 x->ex_xkusage |= XKU_SSL_SERVER;
237                                 break;
238
239                                 case NID_client_auth:
240                                 x->ex_xkusage |= XKU_SSL_CLIENT;
241                                 break;
242
243                                 case NID_email_protect:
244                                 x->ex_xkusage |= XKU_SMIME;
245                                 break;
246
247                                 case NID_code_sign:
248                                 x->ex_xkusage |= XKU_CODE_SIGN;
249                                 break;
250
251                                 case NID_ms_sgc:
252                                 case NID_ns_sgc:
253                                 x->ex_xkusage |= XKU_SGC;
254                         }
255                 }
256                 sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free);
257         }
258
259         if((ns=X509V3_X509_get_d2i(x, NID_netscape_cert_type, NULL, NULL))) {
260                 if(ns->length > 0) x->ex_nscert = ns->data[0];
261                 else x->ex_nscert = 0;
262                 x->ex_flags |= EXFLAG_NSCERT;
263                 ASN1_BIT_STRING_free(ns);
264         }
265         x->ex_flags |= EXFLAG_SET;
266 }
267
268 /* CA checks common to all purposes
269  * return codes:
270  * 0 not a CA
271  * 1 is a CA
272  * 2 basicConstraints absent so "maybe" a CA
273  * 3 basicConstraints absent but self signed V1.
274  */
275
276 #define V1_ROOT (EXFLAG_V1|EXFLAG_SS)
277 #define ku_reject(x, usage) \
278         (((x)->ex_flags & EXFLAG_KUSAGE) && !((x)->ex_kusage & (usage)))
279 #define xku_reject(x, usage) \
280         (((x)->ex_flags & EXFLAG_XKUSAGE) && !((x)->ex_xkusage & (usage)))
281 #define ns_reject(x, usage) \
282         (((x)->ex_flags & EXFLAG_NSCERT) && !((x)->ex_nscert & (usage)))
283
284 static int ca_check(X509 *x)
285 {
286         /* keyUsage if present should allow cert signing */
287         if(ku_reject(x, KU_KEY_CERT_SIGN)) return 0;
288         if(x->ex_flags & EXFLAG_BCONS) {
289                 if(x->ex_flags & EXFLAG_CA) return 1;
290                 /* If basicConstraints says not a CA then say so */
291                 else return 0;
292         } else {
293                 if((x->ex_flags & V1_ROOT) == V1_ROOT) return 3;
294                 else return 2;
295         }
296 }
297
298
299 static int check_purpose_ssl_client(X509_PURPOSE *xp, X509 *x, int ca)
300 {
301         if(xku_reject(x,XKU_SSL_CLIENT)) return 0;
302         if(ca) {
303                 int ca_ret;
304                 ca_ret = ca_check(x);
305                 if(!ca_ret) return 0;
306                 /* check nsCertType if present */
307                 if(x->ex_flags & EXFLAG_NSCERT) {
308                         if(x->ex_nscert & NS_SSL_CA) return ca_ret;
309                         return 0;
310                 }
311                 if(ca_ret != 2) return ca_ret;
312                 else return 0;
313         }
314         /* We need to do digital signatures with it */
315         if(ku_reject(x,KU_DIGITAL_SIGNATURE)) return 0;
316         /* nsCertType if present should allow SSL client use */ 
317         if(ns_reject(x, NS_SSL_CLIENT)) return 0;
318         return 1;
319 }
320
321 static int check_purpose_ssl_server(X509_PURPOSE *xp, X509 *x, int ca)
322 {
323         if(xku_reject(x,XKU_SSL_SERVER|XKU_SGC)) return 0;
324         /* Otherwise same as SSL client for a CA */
325         if(ca) return check_purpose_ssl_client(xp, x, 1);
326
327         if(ns_reject(x, NS_SSL_SERVER)) return 0;
328         /* Now as for keyUsage: we'll at least need to sign OR encipher */
329         if(ku_reject(x, KU_DIGITAL_SIGNATURE|KU_KEY_ENCIPHERMENT)) return 0;
330         
331         return 1;
332
333 }
334
335 static int check_purpose_ns_ssl_server(X509_PURPOSE *xp, X509 *x, int ca)
336 {
337         int ret;
338         ret = check_purpose_ssl_server(xp, x, ca);
339         if(!ret || ca) return ret;
340         /* We need to encipher or Netscape complains */
341         if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0;
342         return ret;
343 }
344
345 /* common S/MIME checks */
346 static int purpose_smime(X509 *x, int ca)
347 {
348         if(xku_reject(x,XKU_SMIME)) return 0;
349         if(ca) {
350                 int ca_ret;
351                 ca_ret = ca_check(x);
352                 if(!ca_ret) return 0;
353                 /* check nsCertType if present */
354                 if(x->ex_flags & EXFLAG_NSCERT) {
355                         if(x->ex_nscert & NS_SMIME_CA) return ca_ret;
356                         return 0;
357                 }
358                 if(ca_ret != 2) return ca_ret;
359                 else return 0;
360         }
361         if(x->ex_flags & EXFLAG_NSCERT) {
362                 if(x->ex_nscert & NS_SMIME) return 1;
363                 /* Workaround for some buggy certificates */
364                 if(x->ex_nscert & NS_SSL_CLIENT) return 2;
365                 return 0;
366         }
367         return 1;
368 }
369
370 static int check_purpose_smime_sign(X509_PURPOSE *xp, X509 *x, int ca)
371 {
372         int ret;
373         ret = purpose_smime(x, ca);
374         if(!ret || ca) return ret;
375         if(ku_reject(x, KU_DIGITAL_SIGNATURE)) return 0;
376         return ret;
377 }
378
379 static int check_purpose_smime_encrypt(X509_PURPOSE *xp, X509 *x, int ca)
380 {
381         int ret;
382         ret = purpose_smime(x, ca);
383         if(!ret || ca) return ret;
384         if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0;
385         return ret;
386 }
387
388 static int check_purpose_crl_sign(X509_PURPOSE *xp, X509 *x, int ca)
389 {
390         if(ca) {
391                 int ca_ret;
392                 if((ca_ret = ca_check(x)) != 2) return ca_ret;
393                 else return 0;
394         }
395         if(ku_reject(x, KU_CRL_SIGN)) return 0;
396         return 1;
397 }