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_ssl_ca(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 static int no_check(X509_PURPOSE *xp, X509 *x, int ca);
  76
  77 static int xp_cmp(X509_PURPOSE **a, X509_PURPOSE **b);
  78 static void xptable_free(X509_PURPOSE *p);
  79
  80 static X509_PURPOSE xstandard[] = {
  81         {X509_PURPOSE_SSL_CLIENT, X509_TRUST_SSL_CLIENT, 0, check_purpose_ssl_client, "SSL client", "sslclient", NULL},
  82         {X509_PURPOSE_SSL_SERVER, X509_TRUST_SSL_SERVER, 0, check_purpose_ssl_server, "SSL server", "sslserver", NULL},
  83         {X509_PURPOSE_NS_SSL_SERVER, X509_TRUST_SSL_SERVER, 0, check_purpose_ns_ssl_server, "Netscape SSL server", "nssslserver", NULL},
  84         {X509_PURPOSE_SMIME_SIGN, X509_TRUST_EMAIL, 0, check_purpose_smime_sign, "S/MIME signing", "smimesign", NULL},
  85         {X509_PURPOSE_SMIME_ENCRYPT, X509_TRUST_EMAIL, 0, check_purpose_smime_encrypt, "S/MIME encryption", "smimeencrypt", NULL},
  86         {X509_PURPOSE_CRL_SIGN, X509_TRUST_COMPAT, 0, check_purpose_crl_sign, "CRL signing", "crlsign", NULL},
  87         {X509_PURPOSE_ANY, X509_TRUST_DEFAULT, 0, no_check, "Any Purpose", "any", NULL},
  88 };
  89
  90 #define X509_PURPOSE_COUNT (sizeof(xstandard)/sizeof(X509_PURPOSE))
  91
  92 IMPLEMENT_STACK_OF(X509_PURPOSE)
  93
  94 static STACK_OF(X509_PURPOSE) *xptable = NULL;
  95
  96 static int xp_cmp(X509_PURPOSE **a, X509_PURPOSE **b)
  97 {
  98         return (*a)->purpose - (*b)->purpose;
  99 }
 100
 101 int X509_check_purpose(X509 *x, int id, int ca)
 102 {
 103         int idx;
 104         X509_PURPOSE *pt;
 105         if(!(x->ex_flags & EXFLAG_SET)) {
 106                 CRYPTO_w_lock(CRYPTO_LOCK_X509);
 107                 x509v3_cache_extensions(x);
 108                 CRYPTO_w_unlock(CRYPTO_LOCK_X509);
 109         }
 110         if(id == -1) return 1;
 111         idx = X509_PURPOSE_get_by_id(id);
 112         if(idx == -1) return -1;
 113         pt = X509_PURPOSE_get0(idx);
 114         return pt->check_purpose(pt, x, ca);
 115 }
 116
 117 int X509_PURPOSE_get_count(void)
 118 {
 119         if(!xptable) return X509_PURPOSE_COUNT;
 120         return sk_X509_PURPOSE_num(xptable) + X509_PURPOSE_COUNT;
 121 }
 122
 123 X509_PURPOSE * X509_PURPOSE_get0(int idx)
 124 {
 125         if(idx < 0) return NULL;
 126         if(idx < X509_PURPOSE_COUNT) return xstandard + idx;
 127         return sk_X509_PURPOSE_value(xptable, idx - X509_PURPOSE_COUNT);
 128 }
 129
 130 int X509_PURPOSE_get_by_sname(char *sname)
 131 {
 132         int i;
 133         X509_PURPOSE *xptmp;
 134         for(i = 0; i < X509_PURPOSE_get_count(); i++) {
 135                 xptmp = X509_PURPOSE_get0(i);
 136                 if(!strcmp(xptmp->sname, sname)) return i;
 137         }
 138         return -1;
 139 }
 140
 141
 142 int X509_PURPOSE_get_by_id(int purpose)
 143 {
 144         X509_PURPOSE tmp;
 145         int idx;
 146         if((purpose >= X509_PURPOSE_MIN) && (purpose <= X509_PURPOSE_MAX))
 147                 return purpose - X509_PURPOSE_MIN;
 148         tmp.purpose = purpose;
 149         if(!xptable) return -1;
 150         idx = sk_X509_PURPOSE_find(xptable, &tmp);
 151         if(idx == -1) return -1;
 152         return idx + X509_PURPOSE_COUNT;
 153 }
 154
 155 int X509_PURPOSE_add(int id, int trust, int flags,
 156                         int (*ck)(X509_PURPOSE *, X509 *, int),
 157                                         char *name, char *sname, void *arg)
 158 {
 159         int idx;
 160         X509_PURPOSE *ptmp;
 161         /* This is set according to what we change: application can't set it */
 162         flags &= ~X509_PURPOSE_DYNAMIC;
 163         /* This will always be set for application modified trust entries */
 164         flags |= X509_PURPOSE_DYNAMIC_NAME;
 165         /* Get existing entry if any */
 166         idx = X509_PURPOSE_get_by_id(id);
 167         /* Need a new entry */
 168         if(idx == -1) {
 169                 if(!(ptmp = Malloc(sizeof(X509_PURPOSE)))) {
 170                         X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
 171                         return 0;
 172                 }
 173                 ptmp->flags = X509_PURPOSE_DYNAMIC;
 174         } else ptmp = X509_PURPOSE_get0(idx);
 175
 176         /* Free existing name if dynamic */
 177         if(ptmp->flags & X509_PURPOSE_DYNAMIC_NAME) {
 178                 Free(ptmp->name);
 179                 Free(ptmp->sname);
 180         }
 181         /* dup supplied name */
 182         ptmp->name = BUF_strdup(name);
 183         ptmp->sname = BUF_strdup(sname);
 184         if(!ptmp->name || !ptmp->sname) {
 185                 X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
 186                 return 0;
 187         }
 188         /* Keep the dynamic flag of existing entry */
 189         ptmp->flags &= X509_PURPOSE_DYNAMIC;
 190         /* Set all other flags */
 191         ptmp->flags |= flags;
 192
 193         ptmp->purpose = id;
 194         ptmp->trust = trust;
 195         ptmp->check_purpose = ck;
 196         ptmp->usr_data = arg;
 197
 198         /* If its a new entry manage the dynamic table */
 199         if(idx == -1) {
 200                 if(!xptable && !(xptable = sk_X509_PURPOSE_new(xp_cmp))) {
 201                         X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
 202                         return 0;
 203                 }
 204                 if (!sk_X509_PURPOSE_push(xptable, ptmp)) {
 205                         X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
 206                         return 0;
 207                 }
 208         }
 209         return 1;
 210 }
 211
 212 static void xptable_free(X509_PURPOSE *p)
 213         {
 214         if(!p) return;
 215         if (p->flags & X509_PURPOSE_DYNAMIC)
 216                 {
 217                 if (p->flags & X509_PURPOSE_DYNAMIC_NAME) {
 218                         Free(p->name);
 219                         Free(p->sname);
 220                 }
 221                 Free(p);
 222                 }
 223         }
 224
 225 void X509_PURPOSE_cleanup(void)
 226 {
 227         int i;
 228         sk_X509_PURPOSE_pop_free(xptable, xptable_free);
 229         for(i = 0; i < X509_PURPOSE_COUNT; i++) xptable_free(xstandard + i);
 230         xptable = NULL;
 231 }
 232
 233 int X509_PURPOSE_get_id(X509_PURPOSE *xp)
 234 {
 235         return xp->purpose;
 236 }
 237
 238 char *X509_PURPOSE_get0_name(X509_PURPOSE *xp)
 239 {
 240         return xp->name;
 241 }
 242
 243 char *X509_PURPOSE_get0_sname(X509_PURPOSE *xp)
 244 {
 245         return xp->sname;
 246 }
 247
 248 int X509_PURPOSE_get_trust(X509_PURPOSE *xp)
 249 {
 250         return xp->trust;
 251 }
 252
 253 #ifndef NO_SHA
 254 static void x509v3_cache_extensions(X509 *x)
 255 {
 256         BASIC_CONSTRAINTS *bs;
 257         ASN1_BIT_STRING *usage;
 258         ASN1_BIT_STRING *ns;
 259         STACK_OF(ASN1_OBJECT) *extusage;
 260         int i;
 261         if(x->ex_flags & EXFLAG_SET) return;
 262         X509_digest(x, EVP_sha1(), x->sha1_hash, NULL);
 263         /* Does subject name match issuer ? */
 264         if(!X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x)))
 265                          x->ex_flags |= EXFLAG_SS;
 266         /* V1 should mean no extensions ... */
 267         if(!X509_get_version(x)) x->ex_flags |= EXFLAG_V1;
 268         /* Handle basic constraints */
 269         if((bs=X509_get_ext_d2i(x, NID_basic_constraints, NULL, NULL))) {
 270                 if(bs->ca) x->ex_flags |= EXFLAG_CA;
 271                 if(bs->pathlen) {
 272                         if((bs->pathlen->type == V_ASN1_NEG_INTEGER)
 273                                                 || !bs->ca) {
 274                                 x->ex_flags |= EXFLAG_INVALID;
 275                                 x->ex_pathlen = 0;
 276                         } else x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen);
 277                 } else x->ex_pathlen = -1;
 278                 BASIC_CONSTRAINTS_free(bs);
 279                 x->ex_flags |= EXFLAG_BCONS;
 280         }
 281         /* Handle key usage */
 282         if((usage=X509_get_ext_d2i(x, NID_key_usage, NULL, NULL))) {
 283                 if(usage->length > 0) {
 284                         x->ex_kusage = usage->data[0];
 285                         if(usage->length > 1)
 286                                 x->ex_kusage |= usage->data[1] << 8;
 287                 } else x->ex_kusage = 0;
 288                 x->ex_flags |= EXFLAG_KUSAGE;
 289                 ASN1_BIT_STRING_free(usage);
 290         }
 291         x->ex_xkusage = 0;
 292         if((extusage=X509_get_ext_d2i(x, NID_ext_key_usage, NULL, NULL))) {
 293                 x->ex_flags |= EXFLAG_XKUSAGE;
 294                 for(i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) {
 295                         switch(OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage,i))) {
 296                                 case NID_server_auth:
 297                                 x->ex_xkusage |= XKU_SSL_SERVER;
 298                                 break;
 299
 300                                 case NID_client_auth:
 301                                 x->ex_xkusage |= XKU_SSL_CLIENT;
 302                                 break;
 303
 304                                 case NID_email_protect:
 305                                 x->ex_xkusage |= XKU_SMIME;
 306                                 break;
 307
 308                                 case NID_code_sign:
 309                                 x->ex_xkusage |= XKU_CODE_SIGN;
 310                                 break;
 311
 312                                 case NID_ms_sgc:
 313                                 case NID_ns_sgc:
 314                                 x->ex_xkusage |= XKU_SGC;
 315                         }
 316                 }
 317                 sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free);
 318         }
 319
 320         if((ns=X509_get_ext_d2i(x, NID_netscape_cert_type, NULL, NULL))) {
 321                 if(ns->length > 0) x->ex_nscert = ns->data[0];
 322                 else x->ex_nscert = 0;
 323                 x->ex_flags |= EXFLAG_NSCERT;
 324                 ASN1_BIT_STRING_free(ns);
 325         }
 326         x->ex_flags |= EXFLAG_SET;
 327 }
 328 #endif
 329
 330 /* CA checks common to all purposes
 331  * return codes:
 332  * 0 not a CA
 333  * 1 is a CA
 334  * 2 basicConstraints absent so "maybe" a CA
 335  * 3 basicConstraints absent but self signed V1.
 336  */
 337
 338 #define V1_ROOT (EXFLAG_V1|EXFLAG_SS)
 339 #define ku_reject(x, usage) \
 340         (((x)->ex_flags & EXFLAG_KUSAGE) && !((x)->ex_kusage & (usage)))
 341 #define xku_reject(x, usage) \
 342         (((x)->ex_flags & EXFLAG_XKUSAGE) && !((x)->ex_xkusage & (usage)))
 343 #define ns_reject(x, usage) \
 344         (((x)->ex_flags & EXFLAG_NSCERT) && !((x)->ex_nscert & (usage)))
 345
 346 static int ca_check(X509 *x)
 347 {
 348         /* keyUsage if present should allow cert signing */
 349         if(ku_reject(x, KU_KEY_CERT_SIGN)) return 0;
 350         if(x->ex_flags & EXFLAG_BCONS) {
 351                 if(x->ex_flags & EXFLAG_CA) return 1;
 352                 /* If basicConstraints says not a CA then say so */
 353                 else return 0;
 354         } else {
 355                 if((x->ex_flags & V1_ROOT) == V1_ROOT) return 3;
 356                 else return 2;
 357         }
 358 }
 359
 360 /* Check SSL CA: common checks for SSL client and server */
 361 static int check_ssl_ca(X509 *x)
 362 {
 363         int ca_ret;
 364         ca_ret = ca_check(x);
 365         if(!ca_ret) return 0;
 366         /* check nsCertType if present */
 367         if(x->ex_flags & EXFLAG_NSCERT) {
 368                 if(x->ex_nscert & NS_SSL_CA) return ca_ret;
 369                 return 0;
 370         }
 371         if(ca_ret != 2) return ca_ret;
 372         else return 0;
 373 }
 374
 375
 376 static int check_purpose_ssl_client(X509_PURPOSE *xp, X509 *x, int ca)
 377 {
 378         if(xku_reject(x,XKU_SSL_CLIENT)) return 0;
 379         if(ca) return check_ssl_ca(x);
 380         /* We need to do digital signatures with it */
 381         if(ku_reject(x,KU_DIGITAL_SIGNATURE)) return 0;
 382         /* nsCertType if present should allow SSL client use */
 383         if(ns_reject(x, NS_SSL_CLIENT)) return 0;
 384         return 1;
 385 }
 386
 387 static int check_purpose_ssl_server(X509_PURPOSE *xp, X509 *x, int ca)
 388 {
 389         if(xku_reject(x,XKU_SSL_SERVER|XKU_SGC)) return 0;
 390         if(ca) return check_ssl_ca(x);
 391
 392         if(ns_reject(x, NS_SSL_SERVER)) return 0;
 393         /* Now as for keyUsage: we'll at least need to sign OR encipher */
 394         if(ku_reject(x, KU_DIGITAL_SIGNATURE|KU_KEY_ENCIPHERMENT)) return 0;
 395
 396         return 1;
 397
 398 }
 399
 400 static int check_purpose_ns_ssl_server(X509_PURPOSE *xp, X509 *x, int ca)
 401 {
 402         int ret;
 403         ret = check_purpose_ssl_server(xp, x, ca);
 404         if(!ret || ca) return ret;
 405         /* We need to encipher or Netscape complains */
 406         if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0;
 407         return ret;
 408 }
 409
 410 /* common S/MIME checks */
 411 static int purpose_smime(X509 *x, int ca)
 412 {
 413         if(xku_reject(x,XKU_SMIME)) return 0;
 414         if(ca) {
 415                 int ca_ret;
 416                 ca_ret = ca_check(x);
 417                 if(!ca_ret) return 0;
 418                 /* check nsCertType if present */
 419                 if(x->ex_flags & EXFLAG_NSCERT) {
 420                         if(x->ex_nscert & NS_SMIME_CA) return ca_ret;
 421                         return 0;
 422                 }
 423                 if(ca_ret != 2) return ca_ret;
 424                 else return 0;
 425         }
 426         if(x->ex_flags & EXFLAG_NSCERT) {
 427                 if(x->ex_nscert & NS_SMIME) return 1;
 428                 /* Workaround for some buggy certificates */
 429                 if(x->ex_nscert & NS_SSL_CLIENT) return 2;
 430                 return 0;
 431         }
 432         return 1;
 433 }
 434
 435 static int check_purpose_smime_sign(X509_PURPOSE *xp, X509 *x, int ca)
 436 {
 437         int ret;
 438         ret = purpose_smime(x, ca);
 439         if(!ret || ca) return ret;
 440         if(ku_reject(x, KU_DIGITAL_SIGNATURE)) return 0;
 441         return ret;
 442 }
 443
 444 static int check_purpose_smime_encrypt(X509_PURPOSE *xp, X509 *x, int ca)
 445 {
 446         int ret;
 447         ret = purpose_smime(x, ca);
 448         if(!ret || ca) return ret;
 449         if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0;
 450         return ret;
 451 }
 452
 453 static int check_purpose_crl_sign(X509_PURPOSE *xp, X509 *x, int ca)
 454 {
 455         if(ca) {
 456                 int ca_ret;
 457                 if((ca_ret = ca_check(x)) != 2) return ca_ret;
 458                 else return 0;
 459         }
 460         if(ku_reject(x, KU_CRL_SIGN)) return 0;
 461         return 1;
 462 }
 463
 464 static int no_check(X509_PURPOSE *xp, X509 *x, int ca)
 465 {
 466         return 1;
 467 }