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 };
  86
  87 #define X509_PURPOSE_COUNT (sizeof(xstandard)/sizeof(X509_PURPOSE))
  88
  89 IMPLEMENT_STACK_OF(X509_PURPOSE)
  90
  91 static STACK_OF(X509_PURPOSE) *xptable = NULL;
  92
  93 static int xp_cmp(X509_PURPOSE **a, X509_PURPOSE **b)
  94 {
  95         return (*a)->purpose - (*b)->purpose;
  96 }
  97
  98 int X509_check_purpose(X509 *x, int id, int ca)
  99 {
 100         int idx;
 101         X509_PURPOSE *pt;
 102         if(!(x->ex_flags & EXFLAG_SET)) {
 103                 CRYPTO_w_lock(CRYPTO_LOCK_X509);
 104                 x509v3_cache_extensions(x);
 105                 CRYPTO_w_unlock(CRYPTO_LOCK_X509);
 106         }
 107         if(id == -1) return 1;
 108         idx = X509_PURPOSE_get_by_id(id);
 109         if(idx == -1) return -1;
 110         pt = X509_PURPOSE_iget(idx);
 111         return pt->check_purpose(pt, x, ca);
 112 }
 113
 114 int X509_PURPOSE_get_count(void)
 115 {
 116         if(!xptable) return X509_PURPOSE_COUNT;
 117         return sk_X509_PURPOSE_num(xptable) + X509_PURPOSE_COUNT;
 118 }
 119
 120 X509_PURPOSE * X509_PURPOSE_iget(int idx)
 121 {
 122         if(idx < 0) return NULL;
 123         if(idx < X509_PURPOSE_COUNT) return xstandard + idx;
 124         return sk_X509_PURPOSE_value(xptable, idx - X509_PURPOSE_COUNT);
 125 }
 126
 127 int X509_PURPOSE_get_by_sname(char *sname)
 128 {
 129         int i;
 130         X509_PURPOSE *xptmp;
 131         for(i = 0; i < X509_PURPOSE_get_count(); i++) {
 132                 xptmp = X509_PURPOSE_iget(i);
 133                 if(!strcmp(xptmp->sname, sname)) return i;
 134         }
 135         return -1;
 136 }
 137
 138
 139 int X509_PURPOSE_get_by_id(int purpose)
 140 {
 141         X509_PURPOSE tmp;
 142         int idx;
 143         if((purpose >= X509_PURPOSE_MIN) && (purpose <= X509_PURPOSE_MAX))
 144                 return purpose - X509_PURPOSE_MIN;
 145         tmp.purpose = purpose;
 146         if(!xptable) return -1;
 147         idx = sk_X509_PURPOSE_find(xptable, &tmp);
 148         if(idx == -1) return -1;
 149         return idx + X509_PURPOSE_COUNT;
 150 }
 151
 152 int X509_PURPOSE_add(int id, int trust, int flags,
 153                         int (*ck)(X509_PURPOSE *, X509 *, int),
 154                                         char *name, char *sname, void *arg)
 155 {
 156         int idx;
 157         X509_PURPOSE *ptmp;
 158         /* This is set according to what we change: application can't set it */
 159         flags &= ~X509_PURPOSE_DYNAMIC;
 160         /* This will always be set for application modified trust entries */
 161         flags |= X509_PURPOSE_DYNAMIC_NAME;
 162         /* Get existing entry if any */
 163         idx = X509_PURPOSE_get_by_id(id);
 164         /* Need a new entry */
 165         if(idx == -1) {
 166                 if(!(ptmp = Malloc(sizeof(X509_PURPOSE)))) {
 167                         X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
 168                         return 0;
 169                 }
 170                 ptmp->flags = X509_PURPOSE_DYNAMIC;
 171         } else ptmp = X509_PURPOSE_iget(idx);
 172
 173         /* Free existing name if dynamic */
 174         if(ptmp->flags & X509_PURPOSE_DYNAMIC_NAME) {
 175                 Free(ptmp->name);
 176                 Free(ptmp->sname);
 177         }
 178         /* dup supplied name */
 179         ptmp->name = BUF_strdup(name);
 180         ptmp->sname = BUF_strdup(sname);
 181         if(!ptmp->name || !ptmp->sname) {
 182                 X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
 183                 return 0;
 184         }
 185         /* Keep the dynamic flag of existing entry */
 186         ptmp->flags &= X509_PURPOSE_DYNAMIC;
 187         /* Set all other flags */
 188         ptmp->flags |= flags;
 189
 190         ptmp->purpose = id;
 191         ptmp->trust = trust;
 192         ptmp->check_purpose = ck;
 193         ptmp->usr_data = arg;
 194
 195         /* If its a new entry manage the dynamic table */
 196         if(idx == -1) {
 197                 if(!xptable && !(xptable = sk_X509_PURPOSE_new(xp_cmp))) {
 198                         X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
 199                         return 0;
 200                 }
 201                 if (!sk_X509_PURPOSE_push(xptable, ptmp)) {
 202                         X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
 203                         return 0;
 204                 }
 205         }
 206         return 1;
 207 }
 208
 209 static void xptable_free(X509_PURPOSE *p)
 210         {
 211         if(!p) return;
 212         if (p->flags & X509_PURPOSE_DYNAMIC)
 213                 {
 214                 if (p->flags & X509_PURPOSE_DYNAMIC_NAME) {
 215                         Free(p->name);
 216                         Free(p->sname);
 217                 }
 218                 Free(p);
 219                 }
 220         }
 221
 222 void X509_PURPOSE_cleanup(void)
 223 {
 224         int i;
 225         sk_X509_PURPOSE_pop_free(xptable, xptable_free);
 226         for(i = 0; i < X509_PURPOSE_COUNT; i++) xptable_free(xstandard + i);
 227         xptable = NULL;
 228 }
 229
 230 int X509_PURPOSE_get_id(X509_PURPOSE *xp)
 231 {
 232         return xp->purpose;
 233 }
 234
 235 char *X509_PURPOSE_iget_name(X509_PURPOSE *xp)
 236 {
 237         return xp->name;
 238 }
 239
 240 char *X509_PURPOSE_iget_sname(X509_PURPOSE *xp)
 241 {
 242         return xp->sname;
 243 }
 244
 245 int X509_PURPOSE_get_trust(X509_PURPOSE *xp)
 246 {
 247         return xp->trust;
 248 }
 249
 250 static void x509v3_cache_extensions(X509 *x)
 251 {
 252         BASIC_CONSTRAINTS *bs;
 253         ASN1_BIT_STRING *usage;
 254         ASN1_BIT_STRING *ns;
 255         STACK_OF(ASN1_OBJECT) *extusage;
 256         int i;
 257         if(x->ex_flags & EXFLAG_SET) return;
 258         X509_digest(x, EVP_sha1(), x->sha1_hash, NULL);
 259         /* Does subject name match issuer ? */
 260         if(!X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x)))
 261                          x->ex_flags |= EXFLAG_SS;
 262         /* V1 should mean no extensions ... */
 263         if(!X509_get_version(x)) x->ex_flags |= EXFLAG_V1;
 264         /* Handle basic constraints */
 265         if((bs=X509V3_X509_get_d2i(x, NID_basic_constraints, NULL, NULL))) {
 266                 if(bs->ca) x->ex_flags |= EXFLAG_CA;
 267                 if(bs->pathlen) {
 268                         if((bs->pathlen->type == V_ASN1_NEG_INTEGER)
 269                                                 || !bs->ca) {
 270                                 x->ex_flags |= EXFLAG_INVALID;
 271                                 x->ex_pathlen = 0;
 272                         } else x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen);
 273                 } else x->ex_pathlen = -1;
 274                 BASIC_CONSTRAINTS_free(bs);
 275                 x->ex_flags |= EXFLAG_BCONS;
 276         }
 277         /* Handle key usage */
 278         if((usage=X509V3_X509_get_d2i(x, NID_key_usage, NULL, NULL))) {
 279                 if(usage->length > 0) {
 280                         x->ex_kusage = usage->data[0];
 281                         if(usage->length > 1)
 282                                 x->ex_kusage |= usage->data[1] << 8;
 283                 } else x->ex_kusage = 0;
 284                 x->ex_flags |= EXFLAG_KUSAGE;
 285                 ASN1_BIT_STRING_free(usage);
 286         }
 287         x->ex_xkusage = 0;
 288         if((extusage=X509V3_X509_get_d2i(x, NID_ext_key_usage, NULL, NULL))) {
 289                 x->ex_flags |= EXFLAG_XKUSAGE;
 290                 for(i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) {
 291                         switch(OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage,i))) {
 292                                 case NID_server_auth:
 293                                 x->ex_xkusage |= XKU_SSL_SERVER;
 294                                 break;
 295
 296                                 case NID_client_auth:
 297                                 x->ex_xkusage |= XKU_SSL_CLIENT;
 298                                 break;
 299
 300                                 case NID_email_protect:
 301                                 x->ex_xkusage |= XKU_SMIME;
 302                                 break;
 303
 304                                 case NID_code_sign:
 305                                 x->ex_xkusage |= XKU_CODE_SIGN;
 306                                 break;
 307
 308                                 case NID_ms_sgc:
 309                                 case NID_ns_sgc:
 310                                 x->ex_xkusage |= XKU_SGC;
 311                         }
 312                 }
 313                 sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free);
 314         }
 315
 316         if((ns=X509V3_X509_get_d2i(x, NID_netscape_cert_type, NULL, NULL))) {
 317                 if(ns->length > 0) x->ex_nscert = ns->data[0];
 318                 else x->ex_nscert = 0;
 319                 x->ex_flags |= EXFLAG_NSCERT;
 320                 ASN1_BIT_STRING_free(ns);
 321         }
 322         x->ex_flags |= EXFLAG_SET;
 323 }
 324
 325 /* CA checks common to all purposes
 326  * return codes:
 327  * 0 not a CA
 328  * 1 is a CA
 329  * 2 basicConstraints absent so "maybe" a CA
 330  * 3 basicConstraints absent but self signed V1.
 331  */
 332
 333 #define V1_ROOT (EXFLAG_V1|EXFLAG_SS)
 334 #define ku_reject(x, usage) \
 335         (((x)->ex_flags & EXFLAG_KUSAGE) && !((x)->ex_kusage & (usage)))
 336 #define xku_reject(x, usage) \
 337         (((x)->ex_flags & EXFLAG_XKUSAGE) && !((x)->ex_xkusage & (usage)))
 338 #define ns_reject(x, usage) \
 339         (((x)->ex_flags & EXFLAG_NSCERT) && !((x)->ex_nscert & (usage)))
 340
 341 static int ca_check(X509 *x)
 342 {
 343         /* keyUsage if present should allow cert signing */
 344         if(ku_reject(x, KU_KEY_CERT_SIGN)) return 0;
 345         if(x->ex_flags & EXFLAG_BCONS) {
 346                 if(x->ex_flags & EXFLAG_CA) return 1;
 347                 /* If basicConstraints says not a CA then say so */
 348                 else return 0;
 349         } else {
 350                 if((x->ex_flags & V1_ROOT) == V1_ROOT) return 3;
 351                 else return 2;
 352         }
 353 }
 354
 355
 356 static int check_purpose_ssl_client(X509_PURPOSE *xp, X509 *x, int ca)
 357 {
 358         if(xku_reject(x,XKU_SSL_CLIENT)) return 0;
 359         if(ca) {
 360                 int ca_ret;
 361                 ca_ret = ca_check(x);
 362                 if(!ca_ret) return 0;
 363                 /* check nsCertType if present */
 364                 if(x->ex_flags & EXFLAG_NSCERT) {
 365                         if(x->ex_nscert & NS_SSL_CA) return ca_ret;
 366                         return 0;
 367                 }
 368                 if(ca_ret != 2) return ca_ret;
 369                 else return 0;
 370         }
 371         /* We need to do digital signatures with it */
 372         if(ku_reject(x,KU_DIGITAL_SIGNATURE)) return 0;
 373         /* nsCertType if present should allow SSL client use */
 374         if(ns_reject(x, NS_SSL_CLIENT)) return 0;
 375         return 1;
 376 }
 377
 378 static int check_purpose_ssl_server(X509_PURPOSE *xp, X509 *x, int ca)
 379 {
 380         if(xku_reject(x,XKU_SSL_SERVER|XKU_SGC)) return 0;
 381         /* Otherwise same as SSL client for a CA */
 382         if(ca) return check_purpose_ssl_client(xp, x, 1);
 383
 384         if(ns_reject(x, NS_SSL_SERVER)) return 0;
 385         /* Now as for keyUsage: we'll at least need to sign OR encipher */
 386         if(ku_reject(x, KU_DIGITAL_SIGNATURE|KU_KEY_ENCIPHERMENT)) return 0;
 387
 388         return 1;
 389
 390 }
 391
 392 static int check_purpose_ns_ssl_server(X509_PURPOSE *xp, X509 *x, int ca)
 393 {
 394         int ret;
 395         ret = check_purpose_ssl_server(xp, x, ca);
 396         if(!ret || ca) return ret;
 397         /* We need to encipher or Netscape complains */
 398         if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0;
 399         return ret;
 400 }
 401
 402 /* common S/MIME checks */
 403 static int purpose_smime(X509 *x, int ca)
 404 {
 405         if(xku_reject(x,XKU_SMIME)) return 0;
 406         if(ca) {
 407                 int ca_ret;
 408                 ca_ret = ca_check(x);
 409                 if(!ca_ret) return 0;
 410                 /* check nsCertType if present */
 411                 if(x->ex_flags & EXFLAG_NSCERT) {
 412                         if(x->ex_nscert & NS_SMIME_CA) return ca_ret;
 413                         return 0;
 414                 }
 415                 if(ca_ret != 2) return ca_ret;
 416                 else return 0;
 417         }
 418         if(x->ex_flags & EXFLAG_NSCERT) {
 419                 if(x->ex_nscert & NS_SMIME) return 1;
 420                 /* Workaround for some buggy certificates */
 421                 if(x->ex_nscert & NS_SSL_CLIENT) return 2;
 422                 return 0;
 423         }
 424         return 1;
 425 }
 426
 427 static int check_purpose_smime_sign(X509_PURPOSE *xp, X509 *x, int ca)
 428 {
 429         int ret;
 430         ret = purpose_smime(x, ca);
 431         if(!ret || ca) return ret;
 432         if(ku_reject(x, KU_DIGITAL_SIGNATURE)) return 0;
 433         return ret;
 434 }
 435
 436 static int check_purpose_smime_encrypt(X509_PURPOSE *xp, X509 *x, int ca)
 437 {
 438         int ret;
 439         ret = purpose_smime(x, ca);
 440         if(!ret || ca) return ret;
 441         if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0;
 442         return ret;
 443 }
 444
 445 static int check_purpose_crl_sign(X509_PURPOSE *xp, X509 *x, int ca)
 446 {
 447         if(ca) {
 448                 int ca_ret;
 449                 if((ca_ret = ca_check(x)) != 2) return ca_ret;
 450                 else return 0;
 451         }
 452         if(ku_reject(x, KU_CRL_SIGN)) return 0;
 453         return 1;
 454 }