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 static int no_check(X509_PURPOSE *xp, X509 *x, int ca);
  75
  76 static int xp_cmp(X509_PURPOSE **a, X509_PURPOSE **b);
  77 static void xptable_free(X509_PURPOSE *p);
  78
  79 static X509_PURPOSE xstandard[] = {
  80         {X509_PURPOSE_SSL_CLIENT, X509_TRUST_SSL_CLIENT, 0, check_purpose_ssl_client, "SSL client", "sslclient", NULL},
  81         {X509_PURPOSE_SSL_SERVER, X509_TRUST_SSL_SERVER, 0, check_purpose_ssl_server, "SSL server", "sslserver", NULL},
  82         {X509_PURPOSE_NS_SSL_SERVER, X509_TRUST_SSL_SERVER, 0, check_purpose_ns_ssl_server, "Netscape SSL server", "nssslserver", NULL},
  83         {X509_PURPOSE_SMIME_SIGN, X509_TRUST_EMAIL, 0, check_purpose_smime_sign, "S/MIME signing", "smimesign", NULL},
  84         {X509_PURPOSE_SMIME_ENCRYPT, X509_TRUST_EMAIL, 0, check_purpose_smime_encrypt, "S/MIME encryption", "smimeencrypt", NULL},
  85         {X509_PURPOSE_CRL_SIGN, X509_TRUST_COMPAT, 0, check_purpose_crl_sign, "CRL signing", "crlsign", NULL},
  86         {X509_PURPOSE_ANY, X509_TRUST_DEFAULT, 0, no_check, "Any Purpose", "any", NULL},
  87 };
  88
  89 #define X509_PURPOSE_COUNT (sizeof(xstandard)/sizeof(X509_PURPOSE))
  90
  91 IMPLEMENT_STACK_OF(X509_PURPOSE)
  92
  93 static STACK_OF(X509_PURPOSE) *xptable = NULL;
  94
  95 static int xp_cmp(X509_PURPOSE **a, X509_PURPOSE **b)
  96 {
  97         return (*a)->purpose - (*b)->purpose;
  98 }
  99
 100 int X509_check_purpose(X509 *x, int id, int ca)
 101 {
 102         int idx;
 103         X509_PURPOSE *pt;
 104         if(!(x->ex_flags & EXFLAG_SET)) {
 105                 CRYPTO_w_lock(CRYPTO_LOCK_X509);
 106                 x509v3_cache_extensions(x);
 107                 CRYPTO_w_unlock(CRYPTO_LOCK_X509);
 108         }
 109         if(id == -1) return 1;
 110         idx = X509_PURPOSE_get_by_id(id);
 111         if(idx == -1) return -1;
 112         pt = X509_PURPOSE_get0(idx);
 113         return pt->check_purpose(pt, x, ca);
 114 }
 115
 116 int X509_PURPOSE_get_count(void)
 117 {
 118         if(!xptable) return X509_PURPOSE_COUNT;
 119         return sk_X509_PURPOSE_num(xptable) + X509_PURPOSE_COUNT;
 120 }
 121
 122 X509_PURPOSE * X509_PURPOSE_get0(int idx)
 123 {
 124         if(idx < 0) return NULL;
 125         if(idx < X509_PURPOSE_COUNT) return xstandard + idx;
 126         return sk_X509_PURPOSE_value(xptable, idx - X509_PURPOSE_COUNT);
 127 }
 128
 129 int X509_PURPOSE_get_by_sname(char *sname)
 130 {
 131         int i;
 132         X509_PURPOSE *xptmp;
 133         for(i = 0; i < X509_PURPOSE_get_count(); i++) {
 134                 xptmp = X509_PURPOSE_get0(i);
 135                 if(!strcmp(xptmp->sname, sname)) return i;
 136         }
 137         return -1;
 138 }
 139
 140
 141 int X509_PURPOSE_get_by_id(int purpose)
 142 {
 143         X509_PURPOSE tmp;
 144         int idx;
 145         if((purpose >= X509_PURPOSE_MIN) && (purpose <= X509_PURPOSE_MAX))
 146                 return purpose - X509_PURPOSE_MIN;
 147         tmp.purpose = purpose;
 148         if(!xptable) return -1;
 149         idx = sk_X509_PURPOSE_find(xptable, &tmp);
 150         if(idx == -1) return -1;
 151         return idx + X509_PURPOSE_COUNT;
 152 }
 153
 154 int X509_PURPOSE_add(int id, int trust, int flags,
 155                         int (*ck)(X509_PURPOSE *, X509 *, int),
 156                                         char *name, char *sname, void *arg)
 157 {
 158         int idx;
 159         X509_PURPOSE *ptmp;
 160         /* This is set according to what we change: application can't set it */
 161         flags &= ~X509_PURPOSE_DYNAMIC;
 162         /* This will always be set for application modified trust entries */
 163         flags |= X509_PURPOSE_DYNAMIC_NAME;
 164         /* Get existing entry if any */
 165         idx = X509_PURPOSE_get_by_id(id);
 166         /* Need a new entry */
 167         if(idx == -1) {
 168                 if(!(ptmp = Malloc(sizeof(X509_PURPOSE)))) {
 169                         X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
 170                         return 0;
 171                 }
 172                 ptmp->flags = X509_PURPOSE_DYNAMIC;
 173         } else ptmp = X509_PURPOSE_get0(idx);
 174
 175         /* Free existing name if dynamic */
 176         if(ptmp->flags & X509_PURPOSE_DYNAMIC_NAME) {
 177                 Free(ptmp->name);
 178                 Free(ptmp->sname);
 179         }
 180         /* dup supplied name */
 181         ptmp->name = BUF_strdup(name);
 182         ptmp->sname = BUF_strdup(sname);
 183         if(!ptmp->name || !ptmp->sname) {
 184                 X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
 185                 return 0;
 186         }
 187         /* Keep the dynamic flag of existing entry */
 188         ptmp->flags &= X509_PURPOSE_DYNAMIC;
 189         /* Set all other flags */
 190         ptmp->flags |= flags;
 191
 192         ptmp->purpose = id;
 193         ptmp->trust = trust;
 194         ptmp->check_purpose = ck;
 195         ptmp->usr_data = arg;
 196
 197         /* If its a new entry manage the dynamic table */
 198         if(idx == -1) {
 199                 if(!xptable && !(xptable = sk_X509_PURPOSE_new(xp_cmp))) {
 200                         X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
 201                         return 0;
 202                 }
 203                 if (!sk_X509_PURPOSE_push(xptable, ptmp)) {
 204                         X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
 205                         return 0;
 206                 }
 207         }
 208         return 1;
 209 }
 210
 211 static void xptable_free(X509_PURPOSE *p)
 212         {
 213         if(!p) return;
 214         if (p->flags & X509_PURPOSE_DYNAMIC)
 215                 {
 216                 if (p->flags & X509_PURPOSE_DYNAMIC_NAME) {
 217                         Free(p->name);
 218                         Free(p->sname);
 219                 }
 220                 Free(p);
 221                 }
 222         }
 223
 224 void X509_PURPOSE_cleanup(void)
 225 {
 226         int i;
 227         sk_X509_PURPOSE_pop_free(xptable, xptable_free);
 228         for(i = 0; i < X509_PURPOSE_COUNT; i++) xptable_free(xstandard + i);
 229         xptable = NULL;
 230 }
 231
 232 int X509_PURPOSE_get_id(X509_PURPOSE *xp)
 233 {
 234         return xp->purpose;
 235 }
 236
 237 char *X509_PURPOSE_get0_name(X509_PURPOSE *xp)
 238 {
 239         return xp->name;
 240 }
 241
 242 char *X509_PURPOSE_get0_sname(X509_PURPOSE *xp)
 243 {
 244         return xp->sname;
 245 }
 246
 247 int X509_PURPOSE_get_trust(X509_PURPOSE *xp)
 248 {
 249         return xp->trust;
 250 }
 251
 252 #ifndef NO_SHA
 253 static void x509v3_cache_extensions(X509 *x)
 254 {
 255         BASIC_CONSTRAINTS *bs;
 256         ASN1_BIT_STRING *usage;
 257         ASN1_BIT_STRING *ns;
 258         STACK_OF(ASN1_OBJECT) *extusage;
 259         int i;
 260         if(x->ex_flags & EXFLAG_SET) return;
 261         X509_digest(x, EVP_sha1(), x->sha1_hash, NULL);
 262         /* Does subject name match issuer ? */
 263         if(!X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x)))
 264                          x->ex_flags |= EXFLAG_SS;
 265         /* V1 should mean no extensions ... */
 266         if(!X509_get_version(x)) x->ex_flags |= EXFLAG_V1;
 267         /* Handle basic constraints */
 268         if((bs=X509_get_ext_d2i(x, NID_basic_constraints, NULL, NULL))) {
 269                 if(bs->ca) x->ex_flags |= EXFLAG_CA;
 270                 if(bs->pathlen) {
 271                         if((bs->pathlen->type == V_ASN1_NEG_INTEGER)
 272                                                 || !bs->ca) {
 273                                 x->ex_flags |= EXFLAG_INVALID;
 274                                 x->ex_pathlen = 0;
 275                         } else x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen);
 276                 } else x->ex_pathlen = -1;
 277                 BASIC_CONSTRAINTS_free(bs);
 278                 x->ex_flags |= EXFLAG_BCONS;
 279         }
 280         /* Handle key usage */
 281         if((usage=X509_get_ext_d2i(x, NID_key_usage, NULL, NULL))) {
 282                 if(usage->length > 0) {
 283                         x->ex_kusage = usage->data[0];
 284                         if(usage->length > 1)
 285                                 x->ex_kusage |= usage->data[1] << 8;
 286                 } else x->ex_kusage = 0;
 287                 x->ex_flags |= EXFLAG_KUSAGE;
 288                 ASN1_BIT_STRING_free(usage);
 289         }
 290         x->ex_xkusage = 0;
 291         if((extusage=X509_get_ext_d2i(x, NID_ext_key_usage, NULL, NULL))) {
 292                 x->ex_flags |= EXFLAG_XKUSAGE;
 293                 for(i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) {
 294                         switch(OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage,i))) {
 295                                 case NID_server_auth:
 296                                 x->ex_xkusage |= XKU_SSL_SERVER;
 297                                 break;
 298
 299                                 case NID_client_auth:
 300                                 x->ex_xkusage |= XKU_SSL_CLIENT;
 301                                 break;
 302
 303                                 case NID_email_protect:
 304                                 x->ex_xkusage |= XKU_SMIME;
 305                                 break;
 306
 307                                 case NID_code_sign:
 308                                 x->ex_xkusage |= XKU_CODE_SIGN;
 309                                 break;
 310
 311                                 case NID_ms_sgc:
 312                                 case NID_ns_sgc:
 313                                 x->ex_xkusage |= XKU_SGC;
 314                         }
 315                 }
 316                 sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free);
 317         }
 318
 319         if((ns=X509_get_ext_d2i(x, NID_netscape_cert_type, NULL, NULL))) {
 320                 if(ns->length > 0) x->ex_nscert = ns->data[0];
 321                 else x->ex_nscert = 0;
 322                 x->ex_flags |= EXFLAG_NSCERT;
 323                 ASN1_BIT_STRING_free(ns);
 324         }
 325         x->ex_flags |= EXFLAG_SET;
 326 }
 327 #endif
 328
 329 /* CA checks common to all purposes
 330  * return codes:
 331  * 0 not a CA
 332  * 1 is a CA
 333  * 2 basicConstraints absent so "maybe" a CA
 334  * 3 basicConstraints absent but self signed V1.
 335  */
 336
 337 #define V1_ROOT (EXFLAG_V1|EXFLAG_SS)
 338 #define ku_reject(x, usage) \
 339         (((x)->ex_flags & EXFLAG_KUSAGE) && !((x)->ex_kusage & (usage)))
 340 #define xku_reject(x, usage) \
 341         (((x)->ex_flags & EXFLAG_XKUSAGE) && !((x)->ex_xkusage & (usage)))
 342 #define ns_reject(x, usage) \
 343         (((x)->ex_flags & EXFLAG_NSCERT) && !((x)->ex_nscert & (usage)))
 344
 345 static int ca_check(X509 *x)
 346 {
 347         /* keyUsage if present should allow cert signing */
 348         if(ku_reject(x, KU_KEY_CERT_SIGN)) return 0;
 349         if(x->ex_flags & EXFLAG_BCONS) {
 350                 if(x->ex_flags & EXFLAG_CA) return 1;
 351                 /* If basicConstraints says not a CA then say so */
 352                 else return 0;
 353         } else {
 354                 if((x->ex_flags & V1_ROOT) == V1_ROOT) return 3;
 355                 else return 2;
 356         }
 357 }
 358
 359
 360 static int check_purpose_ssl_client(X509_PURPOSE *xp, X509 *x, int ca)
 361 {
 362         if(xku_reject(x,XKU_SSL_CLIENT)) return 0;
 363         if(ca) {
 364                 int ca_ret;
 365                 ca_ret = ca_check(x);
 366                 if(!ca_ret) return 0;
 367                 /* check nsCertType if present */
 368                 if(x->ex_flags & EXFLAG_NSCERT) {
 369                         if(x->ex_nscert & NS_SSL_CA) return ca_ret;
 370                         return 0;
 371                 }
 372                 if(ca_ret != 2) return ca_ret;
 373                 else return 0;
 374         }
 375         /* We need to do digital signatures with it */
 376         if(ku_reject(x,KU_DIGITAL_SIGNATURE)) return 0;
 377         /* nsCertType if present should allow SSL client use */
 378         if(ns_reject(x, NS_SSL_CLIENT)) return 0;
 379         return 1;
 380 }
 381
 382 static int check_purpose_ssl_server(X509_PURPOSE *xp, X509 *x, int ca)
 383 {
 384         if(xku_reject(x,XKU_SSL_SERVER|XKU_SGC)) return 0;
 385         /* Otherwise same as SSL client for a CA */
 386         if(ca) return check_purpose_ssl_client(xp, x, 1);
 387
 388         if(ns_reject(x, NS_SSL_SERVER)) return 0;
 389         /* Now as for keyUsage: we'll at least need to sign OR encipher */
 390         if(ku_reject(x, KU_DIGITAL_SIGNATURE|KU_KEY_ENCIPHERMENT)) return 0;
 391
 392         return 1;
 393
 394 }
 395
 396 static int check_purpose_ns_ssl_server(X509_PURPOSE *xp, X509 *x, int ca)
 397 {
 398         int ret;
 399         ret = check_purpose_ssl_server(xp, x, ca);
 400         if(!ret || ca) return ret;
 401         /* We need to encipher or Netscape complains */
 402         if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0;
 403         return ret;
 404 }
 405
 406 /* common S/MIME checks */
 407 static int purpose_smime(X509 *x, int ca)
 408 {
 409         if(xku_reject(x,XKU_SMIME)) return 0;
 410         if(ca) {
 411                 int ca_ret;
 412                 ca_ret = ca_check(x);
 413                 if(!ca_ret) return 0;
 414                 /* check nsCertType if present */
 415                 if(x->ex_flags & EXFLAG_NSCERT) {
 416                         if(x->ex_nscert & NS_SMIME_CA) return ca_ret;
 417                         return 0;
 418                 }
 419                 if(ca_ret != 2) return ca_ret;
 420                 else return 0;
 421         }
 422         if(x->ex_flags & EXFLAG_NSCERT) {
 423                 if(x->ex_nscert & NS_SMIME) return 1;
 424                 /* Workaround for some buggy certificates */
 425                 if(x->ex_nscert & NS_SSL_CLIENT) return 2;
 426                 return 0;
 427         }
 428         return 1;
 429 }
 430
 431 static int check_purpose_smime_sign(X509_PURPOSE *xp, X509 *x, int ca)
 432 {
 433         int ret;
 434         ret = purpose_smime(x, ca);
 435         if(!ret || ca) return ret;
 436         if(ku_reject(x, KU_DIGITAL_SIGNATURE)) return 0;
 437         return ret;
 438 }
 439
 440 static int check_purpose_smime_encrypt(X509_PURPOSE *xp, X509 *x, int ca)
 441 {
 442         int ret;
 443         ret = purpose_smime(x, ca);
 444         if(!ret || ca) return ret;
 445         if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0;
 446         return ret;
 447 }
 448
 449 static int check_purpose_crl_sign(X509_PURPOSE *xp, X509 *x, int ca)
 450 {
 451         if(ca) {
 452                 int ca_ret;
 453                 if((ca_ret = ca_check(x)) != 2) return ca_ret;
 454                 else return 0;
 455         }
 456         if(ku_reject(x, KU_CRL_SIGN)) return 0;
 457         return 1;
 458 }
 459
 460 static int no_check(X509_PURPOSE *xp, X509 *x, int ca)
 461 {
 462         return 1;
 463 }