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(const X509 *x);
  67 static int check_ssl_ca(const X509 *x);
  68 static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int ca);
  69 static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca);
  70 static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca);
  71 static int purpose_smime(const X509 *x, int ca);
  72 static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, int ca);
  73 static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int ca);
  74 static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int ca);
  75 static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca);
  76
  77 static int xp_cmp(const X509_PURPOSE * const *a,
  78                 const X509_PURPOSE * const *b);
  79 static void xptable_free(X509_PURPOSE *p);
  80
  81 static X509_PURPOSE xstandard[] = {
  82         {X509_PURPOSE_SSL_CLIENT, X509_TRUST_SSL_CLIENT, 0, check_purpose_ssl_client, "SSL client", "sslclient", NULL},
  83         {X509_PURPOSE_SSL_SERVER, X509_TRUST_SSL_SERVER, 0, check_purpose_ssl_server, "SSL server", "sslserver", NULL},
  84         {X509_PURPOSE_NS_SSL_SERVER, X509_TRUST_SSL_SERVER, 0, check_purpose_ns_ssl_server, "Netscape SSL server", "nssslserver", NULL},
  85         {X509_PURPOSE_SMIME_SIGN, X509_TRUST_EMAIL, 0, check_purpose_smime_sign, "S/MIME signing", "smimesign", NULL},
  86         {X509_PURPOSE_SMIME_ENCRYPT, X509_TRUST_EMAIL, 0, check_purpose_smime_encrypt, "S/MIME encryption", "smimeencrypt", NULL},
  87         {X509_PURPOSE_CRL_SIGN, X509_TRUST_COMPAT, 0, check_purpose_crl_sign, "CRL signing", "crlsign", NULL},
  88         {X509_PURPOSE_ANY, X509_TRUST_DEFAULT, 0, no_check, "Any Purpose", "any", NULL},
  89 };
  90
  91 #define X509_PURPOSE_COUNT (sizeof(xstandard)/sizeof(X509_PURPOSE))
  92
  93 IMPLEMENT_STACK_OF(X509_PURPOSE)
  94
  95 static STACK_OF(X509_PURPOSE) *xptable = NULL;
  96
  97 static int xp_cmp(const X509_PURPOSE * const *a,
  98                 const X509_PURPOSE * const *b)
  99 {
 100         return (*a)->purpose - (*b)->purpose;
 101 }
 102
 103 /* As much as I'd like to make X509_check_purpose use a "const" X509*
 104  * I really can't because it does recalculate hashes and do other non-const
 105  * things. */
 106 int X509_check_purpose(X509 *x, int id, int ca)
 107 {
 108         int idx;
 109         const X509_PURPOSE *pt;
 110         if(!(x->ex_flags & EXFLAG_SET)) {
 111                 CRYPTO_w_lock(CRYPTO_LOCK_X509);
 112                 x509v3_cache_extensions(x);
 113                 CRYPTO_w_unlock(CRYPTO_LOCK_X509);
 114         }
 115         if(id == -1) return 1;
 116         idx = X509_PURPOSE_get_by_id(id);
 117         if(idx == -1) return -1;
 118         pt = X509_PURPOSE_get0(idx);
 119         return pt->check_purpose(pt, x, ca);
 120 }
 121
 122 int X509_PURPOSE_get_count(void)
 123 {
 124         if(!xptable) return X509_PURPOSE_COUNT;
 125         return sk_X509_PURPOSE_num(xptable) + X509_PURPOSE_COUNT;
 126 }
 127
 128 X509_PURPOSE * X509_PURPOSE_get0(int idx)
 129 {
 130         if(idx < 0) return NULL;
 131         if(idx < X509_PURPOSE_COUNT) return xstandard + idx;
 132         return sk_X509_PURPOSE_value(xptable, idx - X509_PURPOSE_COUNT);
 133 }
 134
 135 int X509_PURPOSE_get_by_sname(char *sname)
 136 {
 137         int i;
 138         X509_PURPOSE *xptmp;
 139         for(i = 0; i < X509_PURPOSE_get_count(); i++) {
 140                 xptmp = X509_PURPOSE_get0(i);
 141                 if(!strcmp(xptmp->sname, sname)) return i;
 142         }
 143         return -1;
 144 }
 145
 146
 147 int X509_PURPOSE_get_by_id(int purpose)
 148 {
 149         X509_PURPOSE tmp;
 150         int idx;
 151         if((purpose >= X509_PURPOSE_MIN) && (purpose <= X509_PURPOSE_MAX))
 152                 return purpose - X509_PURPOSE_MIN;
 153         tmp.purpose = purpose;
 154         if(!xptable) return -1;
 155         idx = sk_X509_PURPOSE_find(xptable, &tmp);
 156         if(idx == -1) return -1;
 157         return idx + X509_PURPOSE_COUNT;
 158 }
 159
 160 int X509_PURPOSE_add(int id, int trust, int flags,
 161                         int (*ck)(const X509_PURPOSE *, const X509 *, int),
 162                                         char *name, char *sname, void *arg)
 163 {
 164         int idx;
 165         X509_PURPOSE *ptmp;
 166         /* This is set according to what we change: application can't set it */
 167         flags &= ~X509_PURPOSE_DYNAMIC;
 168         /* This will always be set for application modified trust entries */
 169         flags |= X509_PURPOSE_DYNAMIC_NAME;
 170         /* Get existing entry if any */
 171         idx = X509_PURPOSE_get_by_id(id);
 172         /* Need a new entry */
 173         if(idx == -1) {
 174                 if(!(ptmp = OPENSSL_malloc(sizeof(X509_PURPOSE)))) {
 175                         X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
 176                         return 0;
 177                 }
 178                 ptmp->flags = X509_PURPOSE_DYNAMIC;
 179         } else ptmp = X509_PURPOSE_get0(idx);
 180
 181         /* OPENSSL_free existing name if dynamic */
 182         if(ptmp->flags & X509_PURPOSE_DYNAMIC_NAME) {
 183                 OPENSSL_free(ptmp->name);
 184                 OPENSSL_free(ptmp->sname);
 185         }
 186         /* dup supplied name */
 187         ptmp->name = BUF_strdup(name);
 188         ptmp->sname = BUF_strdup(sname);
 189         if(!ptmp->name || !ptmp->sname) {
 190                 X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
 191                 return 0;
 192         }
 193         /* Keep the dynamic flag of existing entry */
 194         ptmp->flags &= X509_PURPOSE_DYNAMIC;
 195         /* Set all other flags */
 196         ptmp->flags |= flags;
 197
 198         ptmp->purpose = id;
 199         ptmp->trust = trust;
 200         ptmp->check_purpose = ck;
 201         ptmp->usr_data = arg;
 202
 203         /* If its a new entry manage the dynamic table */
 204         if(idx == -1) {
 205                 if(!xptable && !(xptable = sk_X509_PURPOSE_new(xp_cmp))) {
 206                         X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
 207                         return 0;
 208                 }
 209                 if (!sk_X509_PURPOSE_push(xptable, ptmp)) {
 210                         X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE);
 211                         return 0;
 212                 }
 213         }
 214         return 1;
 215 }
 216
 217 static void xptable_free(X509_PURPOSE *p)
 218         {
 219         if(!p) return;
 220         if (p->flags & X509_PURPOSE_DYNAMIC)
 221                 {
 222                 if (p->flags & X509_PURPOSE_DYNAMIC_NAME) {
 223                         OPENSSL_free(p->name);
 224                         OPENSSL_free(p->sname);
 225                 }
 226                 OPENSSL_free(p);
 227                 }
 228         }
 229
 230 void X509_PURPOSE_cleanup(void)
 231 {
 232         int i;
 233         sk_X509_PURPOSE_pop_free(xptable, xptable_free);
 234         for(i = 0; i < X509_PURPOSE_COUNT; i++) xptable_free(xstandard + i);
 235         xptable = NULL;
 236 }
 237
 238 int X509_PURPOSE_get_id(X509_PURPOSE *xp)
 239 {
 240         return xp->purpose;
 241 }
 242
 243 char *X509_PURPOSE_get0_name(X509_PURPOSE *xp)
 244 {
 245         return xp->name;
 246 }
 247
 248 char *X509_PURPOSE_get0_sname(X509_PURPOSE *xp)
 249 {
 250         return xp->sname;
 251 }
 252
 253 int X509_PURPOSE_get_trust(X509_PURPOSE *xp)
 254 {
 255         return xp->trust;
 256 }
 257
 258 #ifndef NO_SHA
 259 static void x509v3_cache_extensions(X509 *x)
 260 {
 261         BASIC_CONSTRAINTS *bs;
 262         ASN1_BIT_STRING *usage;
 263         ASN1_BIT_STRING *ns;
 264         STACK_OF(ASN1_OBJECT) *extusage;
 265         int i;
 266         if(x->ex_flags & EXFLAG_SET) return;
 267         X509_digest(x, EVP_sha1(), x->sha1_hash, NULL);
 268         /* Does subject name match issuer ? */
 269         if(!X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x)))
 270                          x->ex_flags |= EXFLAG_SS;
 271         /* V1 should mean no extensions ... */
 272         if(!X509_get_version(x)) x->ex_flags |= EXFLAG_V1;
 273         /* Handle basic constraints */
 274         if((bs=X509_get_ext_d2i(x, NID_basic_constraints, NULL, NULL))) {
 275                 if(bs->ca) x->ex_flags |= EXFLAG_CA;
 276                 if(bs->pathlen) {
 277                         if((bs->pathlen->type == V_ASN1_NEG_INTEGER)
 278                                                 || !bs->ca) {
 279                                 x->ex_flags |= EXFLAG_INVALID;
 280                                 x->ex_pathlen = 0;
 281                         } else x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen);
 282                 } else x->ex_pathlen = -1;
 283                 BASIC_CONSTRAINTS_free(bs);
 284                 x->ex_flags |= EXFLAG_BCONS;
 285         }
 286         /* Handle key usage */
 287         if((usage=X509_get_ext_d2i(x, NID_key_usage, NULL, NULL))) {
 288                 if(usage->length > 0) {
 289                         x->ex_kusage = usage->data[0];
 290                         if(usage->length > 1)
 291                                 x->ex_kusage |= usage->data[1] << 8;
 292                 } else x->ex_kusage = 0;
 293                 x->ex_flags |= EXFLAG_KUSAGE;
 294                 ASN1_BIT_STRING_free(usage);
 295         }
 296         x->ex_xkusage = 0;
 297         if((extusage=X509_get_ext_d2i(x, NID_ext_key_usage, NULL, NULL))) {
 298                 x->ex_flags |= EXFLAG_XKUSAGE;
 299                 for(i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) {
 300                         switch(OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage,i))) {
 301                                 case NID_server_auth:
 302                                 x->ex_xkusage |= XKU_SSL_SERVER;
 303                                 break;
 304
 305                                 case NID_client_auth:
 306                                 x->ex_xkusage |= XKU_SSL_CLIENT;
 307                                 break;
 308
 309                                 case NID_email_protect:
 310                                 x->ex_xkusage |= XKU_SMIME;
 311                                 break;
 312
 313                                 case NID_code_sign:
 314                                 x->ex_xkusage |= XKU_CODE_SIGN;
 315                                 break;
 316
 317                                 case NID_ms_sgc:
 318                                 case NID_ns_sgc:
 319                                 x->ex_xkusage |= XKU_SGC;
 320                         }
 321                 }
 322                 sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free);
 323         }
 324
 325         if((ns=X509_get_ext_d2i(x, NID_netscape_cert_type, NULL, NULL))) {
 326                 if(ns->length > 0) x->ex_nscert = ns->data[0];
 327                 else x->ex_nscert = 0;
 328                 x->ex_flags |= EXFLAG_NSCERT;
 329                 ASN1_BIT_STRING_free(ns);
 330         }
 331         x->ex_flags |= EXFLAG_SET;
 332 }
 333 #endif
 334
 335 /* CA checks common to all purposes
 336  * return codes:
 337  * 0 not a CA
 338  * 1 is a CA
 339  * 2 basicConstraints absent so "maybe" a CA
 340  * 3 basicConstraints absent but self signed V1.
 341  */
 342
 343 #define V1_ROOT (EXFLAG_V1|EXFLAG_SS)
 344 #define ku_reject(x, usage) \
 345         (((x)->ex_flags & EXFLAG_KUSAGE) && !((x)->ex_kusage & (usage)))
 346 #define xku_reject(x, usage) \
 347         (((x)->ex_flags & EXFLAG_XKUSAGE) && !((x)->ex_xkusage & (usage)))
 348 #define ns_reject(x, usage) \
 349         (((x)->ex_flags & EXFLAG_NSCERT) && !((x)->ex_nscert & (usage)))
 350
 351 static int ca_check(const X509 *x)
 352 {
 353         /* keyUsage if present should allow cert signing */
 354         if(ku_reject(x, KU_KEY_CERT_SIGN)) return 0;
 355         if(x->ex_flags & EXFLAG_BCONS) {
 356                 if(x->ex_flags & EXFLAG_CA) return 1;
 357                 /* If basicConstraints says not a CA then say so */
 358                 else return 0;
 359         } else {
 360                 if((x->ex_flags & V1_ROOT) == V1_ROOT) return 3;
 361                 else return 2;
 362         }
 363 }
 364
 365 /* Check SSL CA: common checks for SSL client and server */
 366 static int check_ssl_ca(const X509 *x)
 367 {
 368         int ca_ret;
 369         ca_ret = ca_check(x);
 370         if(!ca_ret) return 0;
 371         /* check nsCertType if present */
 372         if(x->ex_flags & EXFLAG_NSCERT) {
 373                 if(x->ex_nscert & NS_SSL_CA) return ca_ret;
 374                 return 0;
 375         }
 376         if(ca_ret != 2) return ca_ret;
 377         else return 0;
 378 }
 379
 380
 381 static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int ca)
 382 {
 383         if(xku_reject(x,XKU_SSL_CLIENT)) return 0;
 384         if(ca) return check_ssl_ca(x);
 385         /* We need to do digital signatures with it */
 386         if(ku_reject(x,KU_DIGITAL_SIGNATURE)) return 0;
 387         /* nsCertType if present should allow SSL client use */
 388         if(ns_reject(x, NS_SSL_CLIENT)) return 0;
 389         return 1;
 390 }
 391
 392 static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca)
 393 {
 394         if(xku_reject(x,XKU_SSL_SERVER|XKU_SGC)) return 0;
 395         if(ca) return check_ssl_ca(x);
 396
 397         if(ns_reject(x, NS_SSL_SERVER)) return 0;
 398         /* Now as for keyUsage: we'll at least need to sign OR encipher */
 399         if(ku_reject(x, KU_DIGITAL_SIGNATURE|KU_KEY_ENCIPHERMENT)) return 0;
 400
 401         return 1;
 402
 403 }
 404
 405 static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca)
 406 {
 407         int ret;
 408         ret = check_purpose_ssl_server(xp, x, ca);
 409         if(!ret || ca) return ret;
 410         /* We need to encipher or Netscape complains */
 411         if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0;
 412         return ret;
 413 }
 414
 415 /* common S/MIME checks */
 416 static int purpose_smime(const X509 *x, int ca)
 417 {
 418         if(xku_reject(x,XKU_SMIME)) return 0;
 419         if(ca) {
 420                 int ca_ret;
 421                 ca_ret = ca_check(x);
 422                 if(!ca_ret) return 0;
 423                 /* check nsCertType if present */
 424                 if(x->ex_flags & EXFLAG_NSCERT) {
 425                         if(x->ex_nscert & NS_SMIME_CA) return ca_ret;
 426                         return 0;
 427                 }
 428                 if(ca_ret != 2) return ca_ret;
 429                 else return 0;
 430         }
 431         if(x->ex_flags & EXFLAG_NSCERT) {
 432                 if(x->ex_nscert & NS_SMIME) return 1;
 433                 /* Workaround for some buggy certificates */
 434                 if(x->ex_nscert & NS_SSL_CLIENT) return 2;
 435                 return 0;
 436         }
 437         return 1;
 438 }
 439
 440 static int check_purpose_smime_sign(const X509_PURPOSE *xp, const 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_DIGITAL_SIGNATURE)) return 0;
 446         return ret;
 447 }
 448
 449 static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int ca)
 450 {
 451         int ret;
 452         ret = purpose_smime(x, ca);
 453         if(!ret || ca) return ret;
 454         if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0;
 455         return ret;
 456 }
 457
 458 static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int ca)
 459 {
 460         if(ca) {
 461                 int ca_ret;
 462                 if((ca_ret = ca_check(x)) != 2) return ca_ret;
 463                 else return 0;
 464         }
 465         if(ku_reject(x, KU_CRL_SIGN)) return 0;
 466         return 1;
 467 }
 468
 469 static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca)
 470 {
 471         return 1;
 472 }