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 }