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 void x509v3_cache_extensions(X509 *x);
  65
  66 static int ca_check(X509 *x);
  67 static int check_purpose_ssl_client(X509_PURPOSE *xp, X509 *x, int ca);
  68 static int check_purpose_ssl_server(X509_PURPOSE *xp, X509 *x, int ca);
  69 static int check_purpose_ns_ssl_server(X509_PURPOSE *xp, X509 *x, int ca);
  70 static int purpose_smime(X509 *x, int ca);
  71 static int check_purpose_smime_sign(X509_PURPOSE *xp, X509 *x, int ca);
  72 static int check_purpose_smime_encrypt(X509_PURPOSE *xp, X509 *x, int ca);
  73 static int check_purpose_crl_sign(X509_PURPOSE *xp, X509 *x, int ca);
  74
  75 static int xp_cmp(X509_PURPOSE **a, X509_PURPOSE **b);
  76 static void xptable_free(X509_PURPOSE *p);
  77
  78 static X509_PURPOSE xstandard[] = {
  79         {X509_PURPOSE_SSL_CLIENT, X509_TRUST_SSL_CLIENT, 0, check_purpose_ssl_client, "SSL client", "sslclient", NULL},
  80         {X509_PURPOSE_SSL_SERVER, X509_TRUST_SSL_SERVER, 0, check_purpose_ssl_server, "SSL server", "sslserver", NULL},
  81         {X509_PURPOSE_NS_SSL_SERVER, X509_TRUST_SSL_SERVER, 0, check_purpose_ns_ssl_server, "Netscape SSL server", "nssslserver", NULL},
  82         {X509_PURPOSE_SMIME_SIGN, X509_TRUST_EMAIL, 0, check_purpose_smime_sign, "S/MIME signing", "smimesign", NULL},
  83         {X509_PURPOSE_SMIME_ENCRYPT, X509_TRUST_EMAIL, 0, check_purpose_smime_encrypt, "S/MIME encryption", "smimeencrypt", NULL},
  84         {X509_PURPOSE_CRL_SIGN, X509_TRUST_ANY, 0, check_purpose_crl_sign, "CRL signing", "crlsign", NULL},
  85         {-1, 0, 0, NULL, 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         if(id == -1) return 1;
 107         idx = X509_PURPOSE_get_by_id(id);
 108         if(idx == -1) return -1;
 109         pt = sk_X509_PURPOSE_value(xptable, idx);
 110         return pt->check_purpose(pt, x,ca);
 111 }
 112
 113 int X509_PURPOSE_get_count(void)
 114 {
 115         return sk_X509_PURPOSE_num(xptable);
 116 }
 117
 118 X509_PURPOSE * X509_PURPOSE_iget(int idx)
 119 {
 120         return sk_X509_PURPOSE_value(xptable, idx);
 121 }
 122
 123 int X509_PURPOSE_get_by_sname(char *sname)
 124 {
 125         int i;
 126         X509_PURPOSE *xptmp;
 127         for(i = 0; i < sk_X509_PURPOSE_num(xptable); i++) {
 128                 xptmp = sk_X509_PURPOSE_value(xptable, i);
 129                 if(!strcmp(xptmp->purpose_sname, sname)) return i;
 130         }
 131         return -1;
 132 }
 133
 134
 135 int X509_PURPOSE_get_by_id(int id)
 136 {
 137         X509_PURPOSE tmp;
 138         tmp.purpose_id = id;
 139         if(!xptable) return -1;
 140         return sk_X509_PURPOSE_find(xptable, &tmp);
 141 }
 142
 143 int X509_PURPOSE_add(X509_PURPOSE *xp)
 144 {
 145         int idx;
 146         if(!xptable)
 147                 {
 148                 xptable = sk_X509_PURPOSE_new(xp_cmp);
 149                 if (!xptable)
 150                         {
 151                         X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
 152                         return 0;
 153                         }
 154                 }
 155
 156         idx = X509_PURPOSE_get_by_id(xp->purpose_id);
 157         if(idx != -1) {
 158                 xptable_free(sk_X509_PURPOSE_value(xptable, idx));
 159                 sk_X509_PURPOSE_set(xptable, idx, xp);
 160         } else {
 161                 if (!sk_X509_PURPOSE_push(xptable, xp)) {
 162                         X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
 163                         return 0;
 164                 }
 165         }
 166         return 1;
 167 }
 168
 169 static void xptable_free(X509_PURPOSE *p)
 170         {
 171         if(!p) return;
 172         if (p->purpose_flags & X509_PURPOSE_DYNAMIC)
 173                 {
 174                 if (p->purpose_flags & X509_PURPOSE_DYNAMIC_NAME) {
 175                         Free(p->purpose_name);
 176                         Free(p->purpose_sname);
 177                 }
 178                 Free(p);
 179                 }
 180         }
 181
 182 void X509_PURPOSE_cleanup(void)
 183 {
 184         sk_X509_PURPOSE_pop_free(xptable, xptable_free);
 185         xptable = NULL;
 186 }
 187
 188 void X509_PURPOSE_add_standard(void)
 189 {
 190         X509_PURPOSE *xp;
 191         for(xp = xstandard; xp->purpose_name; xp++)
 192                 X509_PURPOSE_add(xp);
 193 }
 194
 195 int X509_PURPOSE_get_id(X509_PURPOSE *xp)
 196 {
 197         return xp->purpose_id;
 198 }
 199
 200 char *X509_PURPOSE_iget_name(X509_PURPOSE *xp)
 201 {
 202         return xp->purpose_name;
 203 }
 204
 205 char *X509_PURPOSE_iget_sname(X509_PURPOSE *xp)
 206 {
 207         return xp->purpose_sname;
 208 }
 209
 210 int X509_PURPOSE_get_trust(X509_PURPOSE *xp)
 211 {
 212         return xp->trust_id;
 213 }
 214
 215 static void x509v3_cache_extensions(X509 *x)
 216 {
 217         BASIC_CONSTRAINTS *bs;
 218         ASN1_BIT_STRING *usage;
 219         ASN1_BIT_STRING *ns;
 220         STACK_OF(ASN1_OBJECT) *extusage;
 221         int i;
 222         if(x->ex_flags & EXFLAG_SET) return;
 223         X509_digest(x, EVP_sha1(), x->sha1_hash, NULL);
 224         /* Does subject name match issuer ? */
 225         if(!X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x)))
 226                          x->ex_flags |= EXFLAG_SS;
 227         /* V1 should mean no extensions ... */
 228         if(!X509_get_version(x)) x->ex_flags |= EXFLAG_V1;
 229         /* Handle basic constraints */
 230         if((bs=X509V3_X509_get_d2i(x, NID_basic_constraints, NULL, NULL))) {
 231                 if(bs->ca) x->ex_flags |= EXFLAG_CA;
 232                 if(bs->pathlen) {
 233                         if((bs->pathlen->type == V_ASN1_NEG_INTEGER)
 234                                                 || !bs->ca) {
 235                                 x->ex_flags |= EXFLAG_INVALID;
 236                                 x->ex_pathlen = 0;
 237                         } else x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen);
 238                 } else x->ex_pathlen = -1;
 239                 BASIC_CONSTRAINTS_free(bs);
 240                 x->ex_flags |= EXFLAG_BCONS;
 241         }
 242         /* Handle key usage */
 243         if((usage=X509V3_X509_get_d2i(x, NID_key_usage, NULL, NULL))) {
 244                 if(usage->length > 0) {
 245                         x->ex_kusage = usage->data[0];
 246                         if(usage->length > 1)
 247                                 x->ex_kusage |= usage->data[1] << 8;
 248                 } else x->ex_kusage = 0;
 249                 x->ex_flags |= EXFLAG_KUSAGE;
 250                 ASN1_BIT_STRING_free(usage);
 251         }
 252         x->ex_xkusage = 0;
 253         if((extusage=X509V3_X509_get_d2i(x, NID_ext_key_usage, NULL, NULL))) {
 254                 x->ex_flags |= EXFLAG_XKUSAGE;
 255                 for(i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) {
 256                         switch(OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage,i))) {
 257                                 case NID_server_auth:
 258                                 x->ex_xkusage |= XKU_SSL_SERVER;
 259                                 break;
 260
 261                                 case NID_client_auth:
 262                                 x->ex_xkusage |= XKU_SSL_CLIENT;
 263                                 break;
 264
 265                                 case NID_email_protect:
 266                                 x->ex_xkusage |= XKU_SMIME;
 267                                 break;
 268
 269                                 case NID_code_sign:
 270                                 x->ex_xkusage |= XKU_CODE_SIGN;
 271                                 break;
 272
 273                                 case NID_ms_sgc:
 274                                 case NID_ns_sgc:
 275                                 x->ex_xkusage |= XKU_SGC;
 276                         }
 277                 }
 278                 sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free);
 279         }
 280
 281         if((ns=X509V3_X509_get_d2i(x, NID_netscape_cert_type, NULL, NULL))) {
 282                 if(ns->length > 0) x->ex_nscert = ns->data[0];
 283                 else x->ex_nscert = 0;
 284                 x->ex_flags |= EXFLAG_NSCERT;
 285                 ASN1_BIT_STRING_free(ns);
 286         }
 287         x->ex_flags |= EXFLAG_SET;
 288 }
 289
 290 /* CA checks common to all purposes
 291  * return codes:
 292  * 0 not a CA
 293  * 1 is a CA
 294  * 2 basicConstraints absent so "maybe" a CA
 295  * 3 basicConstraints absent but self signed V1.
 296  */
 297
 298 #define V1_ROOT (EXFLAG_V1|EXFLAG_SS)
 299 #define ku_reject(x, usage) \
 300         (((x)->ex_flags & EXFLAG_KUSAGE) && !((x)->ex_kusage & (usage)))
 301 #define xku_reject(x, usage) \
 302         (((x)->ex_flags & EXFLAG_XKUSAGE) && !((x)->ex_xkusage & (usage)))
 303 #define ns_reject(x, usage) \
 304         (((x)->ex_flags & EXFLAG_NSCERT) && !((x)->ex_nscert & (usage)))
 305
 306 static int ca_check(X509 *x)
 307 {
 308         /* keyUsage if present should allow cert signing */
 309         if(ku_reject(x, KU_KEY_CERT_SIGN)) return 0;
 310         if(x->ex_flags & EXFLAG_BCONS) {
 311                 if(x->ex_flags & EXFLAG_CA) return 1;
 312                 /* If basicConstraints says not a CA then say so */
 313                 else return 0;
 314         } else {
 315                 if((x->ex_flags & V1_ROOT) == V1_ROOT) return 3;
 316                 else return 2;
 317         }
 318 }
 319
 320
 321 static int check_purpose_ssl_client(X509_PURPOSE *xp, X509 *x, int ca)
 322 {
 323         if(xku_reject(x,XKU_SSL_CLIENT)) return 0;
 324         if(ca) {
 325                 int ca_ret;
 326                 ca_ret = ca_check(x);
 327                 if(!ca_ret) return 0;
 328                 /* check nsCertType if present */
 329                 if(x->ex_flags & EXFLAG_NSCERT) {
 330                         if(x->ex_nscert & NS_SSL_CA) return ca_ret;
 331                         return 0;
 332                 }
 333                 if(ca_ret != 2) return ca_ret;
 334                 else return 0;
 335         }
 336         /* We need to do digital signatures with it */
 337         if(ku_reject(x,KU_DIGITAL_SIGNATURE)) return 0;
 338         /* nsCertType if present should allow SSL client use */
 339         if(ns_reject(x, NS_SSL_CLIENT)) return 0;
 340         return 1;
 341 }
 342
 343 static int check_purpose_ssl_server(X509_PURPOSE *xp, X509 *x, int ca)
 344 {
 345         if(xku_reject(x,XKU_SSL_SERVER|XKU_SGC)) return 0;
 346         /* Otherwise same as SSL client for a CA */
 347         if(ca) return check_purpose_ssl_client(xp, x, 1);
 348
 349         if(ns_reject(x, NS_SSL_SERVER)) return 0;
 350         /* Now as for keyUsage: we'll at least need to sign OR encipher */
 351         if(ku_reject(x, KU_DIGITAL_SIGNATURE|KU_KEY_ENCIPHERMENT)) return 0;
 352
 353         return 1;
 354
 355 }
 356
 357 static int check_purpose_ns_ssl_server(X509_PURPOSE *xp, X509 *x, int ca)
 358 {
 359         int ret;
 360         ret = check_purpose_ssl_server(xp, x, ca);
 361         if(!ret || ca) return ret;
 362         /* We need to encipher or Netscape complains */
 363         if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0;
 364         return ret;
 365 }
 366
 367 /* common S/MIME checks */
 368 static int purpose_smime(X509 *x, int ca)
 369 {
 370         if(xku_reject(x,XKU_SMIME)) return 0;
 371         if(ca) {
 372                 int ca_ret;
 373                 ca_ret = ca_check(x);
 374                 if(!ca_ret) return 0;
 375                 /* check nsCertType if present */
 376                 if(x->ex_flags & EXFLAG_NSCERT) {
 377                         if(x->ex_nscert & NS_SMIME_CA) return ca_ret;
 378                         return 0;
 379                 }
 380                 if(ca_ret != 2) return ca_ret;
 381                 else return 0;
 382         }
 383         if(x->ex_flags & EXFLAG_NSCERT) {
 384                 if(x->ex_nscert & NS_SMIME) return 1;
 385                 /* Workaround for some buggy certificates */
 386                 if(x->ex_nscert & NS_SSL_CLIENT) return 2;
 387                 return 0;
 388         }
 389         return 1;
 390 }
 391
 392 static int check_purpose_smime_sign(X509_PURPOSE *xp, X509 *x, int ca)
 393 {
 394         int ret;
 395         ret = purpose_smime(x, ca);
 396         if(!ret || ca) return ret;
 397         if(ku_reject(x, KU_DIGITAL_SIGNATURE)) return 0;
 398         return ret;
 399 }
 400
 401 static int check_purpose_smime_encrypt(X509_PURPOSE *xp, X509 *x, int ca)
 402 {
 403         int ret;
 404         ret = purpose_smime(x, ca);
 405         if(!ret || ca) return ret;
 406         if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0;
 407         return ret;
 408 }
 409
 410 static int check_purpose_crl_sign(X509_PURPOSE *xp, X509 *x, int ca)
 411 {
 412         if(ca) {
 413                 int ca_ret;
 414                 if((ca_ret = ca_check(x)) != 2) return ca_ret;
 415                 else return 0;
 416         }
 417         if(ku_reject(x, KU_CRL_SIGN)) return 0;
 418         return 1;
 419 }