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         if(id == -1) return 1;
 107         idx = x509_purpose_get_idx(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
 114
 115
 116 static int x509_purpose_get_idx(int id)
 117 {
 118         X509_PURPOSE tmp;
 119         tmp.purpose_id = id;
 120         if(!xptable) return -1;
 121         return sk_X509_PURPOSE_find(xptable, &tmp);
 122 }
 123
 124 int X509_PURPOSE_add(X509_PURPOSE *xp)
 125 {
 126         int idx;
 127         if(!xptable)
 128                 {
 129                 xptable = sk_X509_PURPOSE_new(xp_cmp);
 130                 if (!xptable)
 131                         {
 132                         X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
 133                         return 0;
 134                         }
 135                 }
 136
 137         idx = x509_purpose_get_idx(xp->purpose_id);
 138         if(idx != -1)
 139                 sk_X509_PURPOSE_set(xptable, idx, xp);
 140         else
 141                 if (!sk_X509_PURPOSE_push(xptable, xp))
 142                         {
 143                         X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
 144                         return 0;
 145                         }
 146         return 1;
 147 }
 148
 149 static void xptable_free(X509_PURPOSE *p)
 150         {
 151         if (p->purpose_flags & X509_PURPOSE_DYNAMIC)
 152                 {
 153                 if (p->purpose_flags & X509_PURPOSE_DYNAMIC_NAME)
 154                         Free(p->purpose_name);
 155                 Free(p);
 156                 }
 157         }
 158
 159 void X509_PURPOSE_cleanup(void)
 160 {
 161         sk_X509_PURPOSE_pop_free(xptable, xptable_free);
 162         xptable = NULL;
 163 }
 164
 165 void X509_PURPOSE_add_standard(void)
 166 {
 167         X509_PURPOSE *xp;
 168         for(xp = xstandard; xp->purpose_name; xp++)
 169                 X509_PURPOSE_add(xp);
 170 }
 171
 172 int X509_PURPOSE_enum(int (*efunc)(X509_PURPOSE *, void *), void *usr)
 173 {
 174         int i;
 175         X509_PURPOSE *xp;
 176         if(!xptable) return 0;
 177         for(i = 0; i < sk_X509_PURPOSE_num(xptable); i++) {
 178                 xp = sk_X509_PURPOSE_value(xptable, i);
 179                 if(!efunc(xp, usr)) return i;
 180         }
 181         return i;
 182 }
 183
 184
 185 int X509_PURPOSE_get_id(X509_PURPOSE *xp)
 186 {
 187         return xp->purpose_id;
 188 }
 189
 190 char *X509_PURPOSE_get_name(X509_PURPOSE *xp)
 191 {
 192         return xp->purpose_name;
 193 }
 194
 195 static void x509v3_cache_extensions(X509 *x)
 196 {
 197         BASIC_CONSTRAINTS *bs;
 198         ASN1_BIT_STRING *usage;
 199         ASN1_BIT_STRING *ns;
 200         STACK_OF(ASN1_OBJECT) *extusage;
 201         int i;
 202         if(x->ex_flags & EXFLAG_SET) return;
 203         X509_digest(x, EVP_sha1(), x->sha1_hash, NULL);
 204         /* Does subject name match issuer ? */
 205         if(X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x)))
 206                          x->ex_flags |= EXFLAG_SS;
 207         /* V1 should mean no extensions ... */
 208         if(!X509_get_version(x)) x->ex_flags |= EXFLAG_V1;
 209         /* Handle basic constraints */
 210         if((bs=X509V3_X509_get_d2i(x, NID_basic_constraints, NULL, NULL))) {
 211                 if(bs->ca) x->ex_flags |= EXFLAG_CA;
 212                 if(bs->pathlen) {
 213                         if((bs->pathlen->type == V_ASN1_NEG_INTEGER)
 214                                                 || !bs->ca) {
 215                                 x->ex_flags |= EXFLAG_INVALID;
 216                                 x->ex_pathlen = 0;
 217                         } else x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen);
 218                 } else x->ex_pathlen = -1;
 219                 BASIC_CONSTRAINTS_free(bs);
 220                 x->ex_flags |= EXFLAG_BCONS;
 221         }
 222         /* Handle key usage */
 223         if((usage=X509V3_X509_get_d2i(x, NID_key_usage, NULL, NULL))) {
 224                 if(usage->length > 0) {
 225                         x->ex_kusage = usage->data[0];
 226                         if(usage->length > 1)
 227                                 x->ex_kusage |= usage->data[1] << 8;
 228                 } else x->ex_kusage = 0;
 229                 x->ex_flags |= EXFLAG_KUSAGE;
 230                 ASN1_BIT_STRING_free(usage);
 231         }
 232         x->ex_xkusage = 0;
 233         if((extusage=X509V3_X509_get_d2i(x, NID_ext_key_usage, NULL, NULL))) {
 234                 x->ex_flags |= EXFLAG_XKUSAGE;
 235                 for(i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) {
 236                         switch(OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage,i))) {
 237                                 case NID_server_auth:
 238                                 x->ex_xkusage |= XKU_SSL_SERVER;
 239                                 break;
 240
 241                                 case NID_client_auth:
 242                                 x->ex_xkusage |= XKU_SSL_CLIENT;
 243                                 break;
 244
 245                                 case NID_email_protect:
 246                                 x->ex_xkusage |= XKU_SMIME;
 247                                 break;
 248
 249                                 case NID_code_sign:
 250                                 x->ex_xkusage |= XKU_CODE_SIGN;
 251                                 break;
 252
 253                                 case NID_ms_sgc:
 254                                 case NID_ns_sgc:
 255                                 x->ex_xkusage |= XKU_SGC;
 256                         }
 257                 }
 258                 sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free);
 259         }
 260
 261         if((ns=X509V3_X509_get_d2i(x, NID_netscape_cert_type, NULL, NULL))) {
 262                 if(ns->length > 0) x->ex_nscert = ns->data[0];
 263                 else x->ex_nscert = 0;
 264                 x->ex_flags |= EXFLAG_NSCERT;
 265                 ASN1_BIT_STRING_free(ns);
 266         }
 267         x->ex_flags |= EXFLAG_SET;
 268 }
 269
 270 /* CA checks common to all purposes
 271  * return codes:
 272  * 0 not a CA
 273  * 1 is a CA
 274  * 2 basicConstraints absent so "maybe" a CA
 275  * 3 basicConstraints absent but self signed V1.
 276  */
 277
 278 #define V1_ROOT (EXFLAG_V1|EXFLAG_SS)
 279 #define ku_reject(x, usage) \
 280         (((x)->ex_flags & EXFLAG_KUSAGE) && !((x)->ex_kusage & (usage)))
 281 #define xku_reject(x, usage) \
 282         (((x)->ex_flags & EXFLAG_XKUSAGE) && !((x)->ex_xkusage & (usage)))
 283 #define ns_reject(x, usage) \
 284         (((x)->ex_flags & EXFLAG_NSCERT) && !((x)->ex_nscert & (usage)))
 285
 286 static int ca_check(X509 *x)
 287 {
 288         /* keyUsage if present should allow cert signing */
 289         if(ku_reject(x, KU_KEY_CERT_SIGN)) return 0;
 290         if(x->ex_flags & EXFLAG_BCONS) {
 291                 if(x->ex_flags & EXFLAG_CA) return 1;
 292                 /* If basicConstraints says not a CA then say so */
 293                 else return 0;
 294         } else {
 295                 if((x->ex_flags & V1_ROOT) == V1_ROOT) return 3;
 296                 else return 2;
 297         }
 298 }
 299
 300
 301 static int check_purpose_ssl_client(X509_PURPOSE *xp, X509 *x, int ca)
 302 {
 303         if(xku_reject(x,XKU_SSL_CLIENT)) return 0;
 304         if(ca) {
 305                 int ca_ret;
 306                 ca_ret = ca_check(x);
 307                 if(!ca_ret) return 0;
 308                 /* check nsCertType if present */
 309                 if(x->ex_flags & EXFLAG_NSCERT) {
 310                         if(x->ex_nscert & NS_SSL_CA) return ca_ret;
 311                         return 0;
 312                 }
 313                 if(ca_ret != 2) return ca_ret;
 314                 else return 0;
 315         }
 316         /* We need to do digital signatures with it */
 317         if(ku_reject(x,KU_DIGITAL_SIGNATURE)) return 0;
 318         /* nsCertType if present should allow SSL client use */
 319         if(ns_reject(x, NS_SSL_CLIENT)) return 0;
 320         return 1;
 321 }
 322
 323 static int check_purpose_ssl_server(X509_PURPOSE *xp, X509 *x, int ca)
 324 {
 325         if(xku_reject(x,XKU_SSL_SERVER|XKU_SGC)) return 0;
 326         /* Otherwise same as SSL client for a CA */
 327         if(ca) return check_purpose_ssl_client(xp, x, 1);
 328
 329         if(ns_reject(x, NS_SSL_SERVER)) return 0;
 330         /* Now as for keyUsage: we'll at least need to sign OR encipher */
 331         if(ku_reject(x, KU_DIGITAL_SIGNATURE|KU_KEY_ENCIPHERMENT)) return 0;
 332
 333         return 1;
 334
 335 }
 336
 337 static int check_purpose_ns_ssl_server(X509_PURPOSE *xp, X509 *x, int ca)
 338 {
 339         int ret;
 340         ret = check_purpose_ssl_server(xp, x, ca);
 341         if(!ret || ca) return ret;
 342         /* We need to encipher or Netscape complains */
 343         if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0;
 344         return ret;
 345 }
 346
 347 /* common S/MIME checks */
 348 static int purpose_smime(X509 *x, int ca)
 349 {
 350         if(xku_reject(x,XKU_SMIME)) return 0;
 351         if(ca) {
 352                 int ca_ret;
 353                 ca_ret = ca_check(x);
 354                 if(!ca_ret) return 0;
 355                 /* check nsCertType if present */
 356                 if(x->ex_flags & EXFLAG_NSCERT) {
 357                         if(x->ex_nscert & NS_SMIME_CA) return ca_ret;
 358                         return 0;
 359                 }
 360                 if(ca_ret != 2) return ca_ret;
 361                 else return 0;
 362         }
 363         if(x->ex_flags & EXFLAG_NSCERT) {
 364                 if(x->ex_nscert & NS_SMIME) return 1;
 365                 /* Workaround for some buggy certificates */
 366                 if(x->ex_nscert & NS_SSL_CLIENT) return 2;
 367                 return 0;
 368         }
 369         return 1;
 370 }
 371
 372 static int check_purpose_smime_sign(X509_PURPOSE *xp, X509 *x, int ca)
 373 {
 374         int ret;
 375         ret = purpose_smime(x, ca);
 376         if(!ret || ca) return ret;
 377         if(ku_reject(x, KU_DIGITAL_SIGNATURE)) return 0;
 378         return ret;
 379 }
 380
 381 static int check_purpose_smime_encrypt(X509_PURPOSE *xp, X509 *x, int ca)
 382 {
 383         int ret;
 384         ret = purpose_smime(x, ca);
 385         if(!ret || ca) return ret;
 386         if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0;
 387         return ret;
 388 }
 389
 390 static int check_purpose_crl_sign(X509_PURPOSE *xp, X509 *x, int ca)
 391 {
 392         if(ca) {
 393                 int ca_ret;
 394                 if((ca_ret = ca_check(x)) != 2) return ca_ret;
 395                 else return 0;
 396         }
 397         if(ku_reject(x, KU_CRL_SIGN)) return 0;
 398         return 1;
 399 }