crypto/openssl/crypto/x509v3/v3_purp.c

   1 /* v3_purp.c */
   2 /*
   3  * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL project
   4  * 2001.
   5  */
   6 /* ====================================================================
   7  * Copyright (c) 1999-2004 The OpenSSL Project.  All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  *
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  *
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in
  18  *    the documentation and/or other materials provided with the
  19  *    distribution.
  20  *
  21  * 3. All advertising materials mentioning features or use of this
  22  *    software must display the following acknowledgment:
  23  *    "This product includes software developed by the OpenSSL Project
  24  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
  25  *
  26  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  27  *    endorse or promote products derived from this software without
  28  *    prior written permission. For written permission, please contact
  29  *    licensing@OpenSSL.org.
  30  *
  31  * 5. Products derived from this software may not be called "OpenSSL"
  32  *    nor may "OpenSSL" appear in their names without prior written
  33  *    permission of the OpenSSL Project.
  34  *
  35  * 6. Redistributions of any form whatsoever must retain the following
  36  *    acknowledgment:
  37  *    "This product includes software developed by the OpenSSL Project
  38  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
  39  *
  40  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  41  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  42  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  43  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  44  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  45  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  46  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  47  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  49  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  50  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  51  * OF THE POSSIBILITY OF SUCH DAMAGE.
  52  * ====================================================================
  53  *
  54  * This product includes cryptographic software written by Eric Young
  55  * (eay@cryptsoft.com).  This product includes software written by Tim
  56  * Hudson (tjh@cryptsoft.com).
  57  *
  58  */
  59
  60 #include <stdio.h>
  61 #include "cryptlib.h"
  62 #include <openssl/x509v3.h>
  63 #include <openssl/x509_vfy.h>
  64
  65 static void x509v3_cache_extensions(X509 *x);
  66
  67 static int check_ssl_ca(const X509 *x);
  68 static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x,
  69                                     int ca);
  70 static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x,
  71                                     int ca);
  72 static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x,
  73                                        int ca);
  74 static int purpose_smime(const X509 *x, int ca);
  75 static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x,
  76                                     int ca);
  77 static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x,
  78                                        int ca);
  79 static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x,
  80                                   int ca);
  81 static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x,
  82                                         int ca);
  83 static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca);
  84 static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca);
  85
  86 static int xp_cmp(const X509_PURPOSE *const *a, const X509_PURPOSE *const *b);
  87 static void xptable_free(X509_PURPOSE *p);
  88
  89 static X509_PURPOSE xstandard[] = {
  90     {X509_PURPOSE_SSL_CLIENT, X509_TRUST_SSL_CLIENT, 0,
  91      check_purpose_ssl_client, "SSL client", "sslclient", NULL},
  92     {X509_PURPOSE_SSL_SERVER, X509_TRUST_SSL_SERVER, 0,
  93      check_purpose_ssl_server, "SSL server", "sslserver", NULL},
  94     {X509_PURPOSE_NS_SSL_SERVER, X509_TRUST_SSL_SERVER, 0,
  95      check_purpose_ns_ssl_server, "Netscape SSL server", "nssslserver", NULL},
  96     {X509_PURPOSE_SMIME_SIGN, X509_TRUST_EMAIL, 0, check_purpose_smime_sign,
  97      "S/MIME signing", "smimesign", NULL},
  98     {X509_PURPOSE_SMIME_ENCRYPT, X509_TRUST_EMAIL, 0,
  99      check_purpose_smime_encrypt, "S/MIME encryption", "smimeencrypt", NULL},
 100     {X509_PURPOSE_CRL_SIGN, X509_TRUST_COMPAT, 0, check_purpose_crl_sign,
 101      "CRL signing", "crlsign", NULL},
 102     {X509_PURPOSE_ANY, X509_TRUST_DEFAULT, 0, no_check, "Any Purpose", "any",
 103      NULL},
 104     {X509_PURPOSE_OCSP_HELPER, X509_TRUST_COMPAT, 0, ocsp_helper,
 105      "OCSP helper", "ocsphelper", NULL},
 106     {X509_PURPOSE_TIMESTAMP_SIGN, X509_TRUST_TSA, 0,
 107      check_purpose_timestamp_sign, "Time Stamp signing", "timestampsign",
 108      NULL},
 109 };
 110
 111 #define X509_PURPOSE_COUNT (sizeof(xstandard)/sizeof(X509_PURPOSE))
 112
 113 IMPLEMENT_STACK_OF(X509_PURPOSE)
 114
 115 static STACK_OF(X509_PURPOSE) *xptable = NULL;
 116
 117 static int xp_cmp(const X509_PURPOSE *const *a, const X509_PURPOSE *const *b)
 118 {
 119     return (*a)->purpose - (*b)->purpose;
 120 }
 121
 122 /*
 123  * As much as I'd like to make X509_check_purpose use a "const" X509* I
 124  * really can't because it does recalculate hashes and do other non-const
 125  * things.
 126  */
 127 int X509_check_purpose(X509 *x, int id, int ca)
 128 {
 129     int idx;
 130     const X509_PURPOSE *pt;
 131     if (!(x->ex_flags & EXFLAG_SET)) {
 132         CRYPTO_w_lock(CRYPTO_LOCK_X509);
 133         x509v3_cache_extensions(x);
 134         CRYPTO_w_unlock(CRYPTO_LOCK_X509);
 135     }
 136     if (id == -1)
 137         return 1;
 138     idx = X509_PURPOSE_get_by_id(id);
 139     if (idx == -1)
 140         return -1;
 141     pt = X509_PURPOSE_get0(idx);
 142     return pt->check_purpose(pt, x, ca);
 143 }
 144
 145 int X509_PURPOSE_set(int *p, int purpose)
 146 {
 147     if (X509_PURPOSE_get_by_id(purpose) == -1) {
 148         X509V3err(X509V3_F_X509_PURPOSE_SET, X509V3_R_INVALID_PURPOSE);
 149         return 0;
 150     }
 151     *p = purpose;
 152     return 1;
 153 }
 154
 155 int X509_PURPOSE_get_count(void)
 156 {
 157     if (!xptable)
 158         return X509_PURPOSE_COUNT;
 159     return sk_X509_PURPOSE_num(xptable) + X509_PURPOSE_COUNT;
 160 }
 161
 162 X509_PURPOSE *X509_PURPOSE_get0(int idx)
 163 {
 164     if (idx < 0)
 165         return NULL;
 166     if (idx < (int)X509_PURPOSE_COUNT)
 167         return xstandard + idx;
 168     return sk_X509_PURPOSE_value(xptable, idx - X509_PURPOSE_COUNT);
 169 }
 170
 171 int X509_PURPOSE_get_by_sname(char *sname)
 172 {
 173     int i;
 174     X509_PURPOSE *xptmp;
 175     for (i = 0; i < X509_PURPOSE_get_count(); i++) {
 176         xptmp = X509_PURPOSE_get0(i);
 177         if (!strcmp(xptmp->sname, sname))
 178             return i;
 179     }
 180     return -1;
 181 }
 182
 183 int X509_PURPOSE_get_by_id(int purpose)
 184 {
 185     X509_PURPOSE tmp;
 186     int idx;
 187     if ((purpose >= X509_PURPOSE_MIN) && (purpose <= X509_PURPOSE_MAX))
 188         return purpose - X509_PURPOSE_MIN;
 189     tmp.purpose = purpose;
 190     if (!xptable)
 191         return -1;
 192     idx = sk_X509_PURPOSE_find(xptable, &tmp);
 193     if (idx == -1)
 194         return -1;
 195     return idx + X509_PURPOSE_COUNT;
 196 }
 197
 198 int X509_PURPOSE_add(int id, int trust, int flags,
 199                      int (*ck) (const X509_PURPOSE *, const X509 *, int),
 200                      char *name, char *sname, void *arg)
 201 {
 202     int idx;
 203     X509_PURPOSE *ptmp;
 204     /*
 205      * This is set according to what we change: application can't set it
 206      */
 207     flags &= ~X509_PURPOSE_DYNAMIC;
 208     /* This will always be set for application modified trust entries */
 209     flags |= X509_PURPOSE_DYNAMIC_NAME;
 210     /* Get existing entry if any */
 211     idx = X509_PURPOSE_get_by_id(id);
 212     /* Need a new entry */
 213     if (idx == -1) {
 214         if (!(ptmp = OPENSSL_malloc(sizeof(X509_PURPOSE)))) {
 215             X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE);
 216             return 0;
 217         }
 218         ptmp->flags = X509_PURPOSE_DYNAMIC;
 219     } else
 220         ptmp = X509_PURPOSE_get0(idx);
 221
 222     /* OPENSSL_free existing name if dynamic */
 223     if (ptmp->flags & X509_PURPOSE_DYNAMIC_NAME) {
 224         OPENSSL_free(ptmp->name);
 225         OPENSSL_free(ptmp->sname);
 226     }
 227     /* dup supplied name */
 228     ptmp->name = BUF_strdup(name);
 229     ptmp->sname = BUF_strdup(sname);
 230     if (!ptmp->name || !ptmp->sname) {
 231         X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE);
 232         return 0;
 233     }
 234     /* Keep the dynamic flag of existing entry */
 235     ptmp->flags &= X509_PURPOSE_DYNAMIC;
 236     /* Set all other flags */
 237     ptmp->flags |= flags;
 238
 239     ptmp->purpose = id;
 240     ptmp->trust = trust;
 241     ptmp->check_purpose = ck;
 242     ptmp->usr_data = arg;
 243
 244     /* If its a new entry manage the dynamic table */
 245     if (idx == -1) {
 246         if (!xptable && !(xptable = sk_X509_PURPOSE_new(xp_cmp))) {
 247             X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE);
 248             return 0;
 249         }
 250         if (!sk_X509_PURPOSE_push(xptable, ptmp)) {
 251             X509V3err(X509V3_F_X509_PURPOSE_ADD, ERR_R_MALLOC_FAILURE);
 252             return 0;
 253         }
 254     }
 255     return 1;
 256 }
 257
 258 static void xptable_free(X509_PURPOSE *p)
 259 {
 260     if (!p)
 261         return;
 262     if (p->flags & X509_PURPOSE_DYNAMIC) {
 263         if (p->flags & X509_PURPOSE_DYNAMIC_NAME) {
 264             OPENSSL_free(p->name);
 265             OPENSSL_free(p->sname);
 266         }
 267         OPENSSL_free(p);
 268     }
 269 }
 270
 271 void X509_PURPOSE_cleanup(void)
 272 {
 273     unsigned int i;
 274     sk_X509_PURPOSE_pop_free(xptable, xptable_free);
 275     for (i = 0; i < X509_PURPOSE_COUNT; i++)
 276         xptable_free(xstandard + i);
 277     xptable = NULL;
 278 }
 279
 280 int X509_PURPOSE_get_id(X509_PURPOSE *xp)
 281 {
 282     return xp->purpose;
 283 }
 284
 285 char *X509_PURPOSE_get0_name(X509_PURPOSE *xp)
 286 {
 287     return xp->name;
 288 }
 289
 290 char *X509_PURPOSE_get0_sname(X509_PURPOSE *xp)
 291 {
 292     return xp->sname;
 293 }
 294
 295 int X509_PURPOSE_get_trust(X509_PURPOSE *xp)
 296 {
 297     return xp->trust;
 298 }
 299
 300 static int nid_cmp(const int *a, const int *b)
 301 {
 302     return *a - *b;
 303 }
 304
 305 DECLARE_OBJ_BSEARCH_CMP_FN(int, int, nid);
 306 IMPLEMENT_OBJ_BSEARCH_CMP_FN(int, int, nid);
 307
 308 int X509_supported_extension(X509_EXTENSION *ex)
 309 {
 310     /*
 311      * This table is a list of the NIDs of supported extensions: that is
 312      * those which are used by the verify process. If an extension is
 313      * critical and doesn't appear in this list then the verify process will
 314      * normally reject the certificate. The list must be kept in numerical
 315      * order because it will be searched using bsearch.
 316      */
 317
 318     static const int supported_nids[] = {
 319         NID_netscape_cert_type, /* 71 */
 320         NID_key_usage,          /* 83 */
 321         NID_subject_alt_name,   /* 85 */
 322         NID_basic_constraints,  /* 87 */
 323         NID_certificate_policies, /* 89 */
 324         NID_ext_key_usage,      /* 126 */
 325 #ifndef OPENSSL_NO_RFC3779
 326         NID_sbgp_ipAddrBlock,   /* 290 */
 327         NID_sbgp_autonomousSysNum, /* 291 */
 328 #endif
 329         NID_policy_constraints, /* 401 */
 330         NID_proxyCertInfo,      /* 663 */
 331         NID_name_constraints,   /* 666 */
 332         NID_policy_mappings,    /* 747 */
 333         NID_inhibit_any_policy  /* 748 */
 334     };
 335
 336     int ex_nid = OBJ_obj2nid(X509_EXTENSION_get_object(ex));
 337
 338     if (ex_nid == NID_undef)
 339         return 0;
 340
 341     if (OBJ_bsearch_nid(&ex_nid, supported_nids,
 342                         sizeof(supported_nids) / sizeof(int)))
 343         return 1;
 344     return 0;
 345 }
 346
 347 static void setup_dp(X509 *x, DIST_POINT *dp)
 348 {
 349     X509_NAME *iname = NULL;
 350     int i;
 351     if (dp->reasons) {
 352         if (dp->reasons->length > 0)
 353             dp->dp_reasons = dp->reasons->data[0];
 354         if (dp->reasons->length > 1)
 355             dp->dp_reasons |= (dp->reasons->data[1] << 8);
 356         dp->dp_reasons &= CRLDP_ALL_REASONS;
 357     } else
 358         dp->dp_reasons = CRLDP_ALL_REASONS;
 359     if (!dp->distpoint || (dp->distpoint->type != 1))
 360         return;
 361     for (i = 0; i < sk_GENERAL_NAME_num(dp->CRLissuer); i++) {
 362         GENERAL_NAME *gen = sk_GENERAL_NAME_value(dp->CRLissuer, i);
 363         if (gen->type == GEN_DIRNAME) {
 364             iname = gen->d.directoryName;
 365             break;
 366         }
 367     }
 368     if (!iname)
 369         iname = X509_get_issuer_name(x);
 370
 371     DIST_POINT_set_dpname(dp->distpoint, iname);
 372
 373 }
 374
 375 static void setup_crldp(X509 *x)
 376 {
 377     int i;
 378     x->crldp = X509_get_ext_d2i(x, NID_crl_distribution_points, NULL, NULL);
 379     for (i = 0; i < sk_DIST_POINT_num(x->crldp); i++)
 380         setup_dp(x, sk_DIST_POINT_value(x->crldp, i));
 381 }
 382
 383 #define V1_ROOT (EXFLAG_V1|EXFLAG_SS)
 384 #define ku_reject(x, usage) \
 385         (((x)->ex_flags & EXFLAG_KUSAGE) && !((x)->ex_kusage & (usage)))
 386 #define xku_reject(x, usage) \
 387         (((x)->ex_flags & EXFLAG_XKUSAGE) && !((x)->ex_xkusage & (usage)))
 388 #define ns_reject(x, usage) \
 389         (((x)->ex_flags & EXFLAG_NSCERT) && !((x)->ex_nscert & (usage)))
 390
 391 static void x509v3_cache_extensions(X509 *x)
 392 {
 393     BASIC_CONSTRAINTS *bs;
 394     PROXY_CERT_INFO_EXTENSION *pci;
 395     ASN1_BIT_STRING *usage;
 396     ASN1_BIT_STRING *ns;
 397     EXTENDED_KEY_USAGE *extusage;
 398     X509_EXTENSION *ex;
 399
 400     int i;
 401     if (x->ex_flags & EXFLAG_SET)
 402         return;
 403 #ifndef OPENSSL_NO_SHA
 404     X509_digest(x, EVP_sha1(), x->sha1_hash, NULL);
 405 #endif
 406     /* V1 should mean no extensions ... */
 407     if (!X509_get_version(x))
 408         x->ex_flags |= EXFLAG_V1;
 409     /* Handle basic constraints */
 410     if ((bs = X509_get_ext_d2i(x, NID_basic_constraints, NULL, NULL))) {
 411         if (bs->ca)
 412             x->ex_flags |= EXFLAG_CA;
 413         if (bs->pathlen) {
 414             if ((bs->pathlen->type == V_ASN1_NEG_INTEGER)
 415                 || !bs->ca) {
 416                 x->ex_flags |= EXFLAG_INVALID;
 417                 x->ex_pathlen = 0;
 418             } else
 419                 x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen);
 420         } else
 421             x->ex_pathlen = -1;
 422         BASIC_CONSTRAINTS_free(bs);
 423         x->ex_flags |= EXFLAG_BCONS;
 424     }
 425     /* Handle proxy certificates */
 426     if ((pci = X509_get_ext_d2i(x, NID_proxyCertInfo, NULL, NULL))) {
 427         if (x->ex_flags & EXFLAG_CA
 428             || X509_get_ext_by_NID(x, NID_subject_alt_name, -1) >= 0
 429             || X509_get_ext_by_NID(x, NID_issuer_alt_name, -1) >= 0) {
 430             x->ex_flags |= EXFLAG_INVALID;
 431         }
 432         if (pci->pcPathLengthConstraint) {
 433             x->ex_pcpathlen = ASN1_INTEGER_get(pci->pcPathLengthConstraint);
 434         } else
 435             x->ex_pcpathlen = -1;
 436         PROXY_CERT_INFO_EXTENSION_free(pci);
 437         x->ex_flags |= EXFLAG_PROXY;
 438     }
 439     /* Handle key usage */
 440     if ((usage = X509_get_ext_d2i(x, NID_key_usage, NULL, NULL))) {
 441         if (usage->length > 0) {
 442             x->ex_kusage = usage->data[0];
 443             if (usage->length > 1)
 444                 x->ex_kusage |= usage->data[1] << 8;
 445         } else
 446             x->ex_kusage = 0;
 447         x->ex_flags |= EXFLAG_KUSAGE;
 448         ASN1_BIT_STRING_free(usage);
 449     }
 450     x->ex_xkusage = 0;
 451     if ((extusage = X509_get_ext_d2i(x, NID_ext_key_usage, NULL, NULL))) {
 452         x->ex_flags |= EXFLAG_XKUSAGE;
 453         for (i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) {
 454             switch (OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage, i))) {
 455             case NID_server_auth:
 456                 x->ex_xkusage |= XKU_SSL_SERVER;
 457                 break;
 458
 459             case NID_client_auth:
 460                 x->ex_xkusage |= XKU_SSL_CLIENT;
 461                 break;
 462
 463             case NID_email_protect:
 464                 x->ex_xkusage |= XKU_SMIME;
 465                 break;
 466
 467             case NID_code_sign:
 468                 x->ex_xkusage |= XKU_CODE_SIGN;
 469                 break;
 470
 471             case NID_ms_sgc:
 472             case NID_ns_sgc:
 473                 x->ex_xkusage |= XKU_SGC;
 474                 break;
 475
 476             case NID_OCSP_sign:
 477                 x->ex_xkusage |= XKU_OCSP_SIGN;
 478                 break;
 479
 480             case NID_time_stamp:
 481                 x->ex_xkusage |= XKU_TIMESTAMP;
 482                 break;
 483
 484             case NID_dvcs:
 485                 x->ex_xkusage |= XKU_DVCS;
 486                 break;
 487
 488             case NID_anyExtendedKeyUsage:
 489                 x->ex_xkusage |= XKU_ANYEKU;
 490                 break;
 491             }
 492         }
 493         sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free);
 494     }
 495
 496     if ((ns = X509_get_ext_d2i(x, NID_netscape_cert_type, NULL, NULL))) {
 497         if (ns->length > 0)
 498             x->ex_nscert = ns->data[0];
 499         else
 500             x->ex_nscert = 0;
 501         x->ex_flags |= EXFLAG_NSCERT;
 502         ASN1_BIT_STRING_free(ns);
 503     }
 504     x->skid = X509_get_ext_d2i(x, NID_subject_key_identifier, NULL, NULL);
 505     x->akid = X509_get_ext_d2i(x, NID_authority_key_identifier, NULL, NULL);
 506     /* Does subject name match issuer ? */
 507     if (!X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x))) {
 508         x->ex_flags |= EXFLAG_SI;
 509         /* If SKID matches AKID also indicate self signed */
 510         if (X509_check_akid(x, x->akid) == X509_V_OK &&
 511             !ku_reject(x, KU_KEY_CERT_SIGN))
 512             x->ex_flags |= EXFLAG_SS;
 513     }
 514     x->altname = X509_get_ext_d2i(x, NID_subject_alt_name, NULL, NULL);
 515     x->nc = X509_get_ext_d2i(x, NID_name_constraints, &i, NULL);
 516     if (!x->nc && (i != -1))
 517         x->ex_flags |= EXFLAG_INVALID;
 518     setup_crldp(x);
 519
 520 #ifndef OPENSSL_NO_RFC3779
 521     x->rfc3779_addr = X509_get_ext_d2i(x, NID_sbgp_ipAddrBlock, NULL, NULL);
 522     x->rfc3779_asid = X509_get_ext_d2i(x, NID_sbgp_autonomousSysNum,
 523                                        NULL, NULL);
 524 #endif
 525     for (i = 0; i < X509_get_ext_count(x); i++) {
 526         ex = X509_get_ext(x, i);
 527         if (OBJ_obj2nid(X509_EXTENSION_get_object(ex))
 528             == NID_freshest_crl)
 529             x->ex_flags |= EXFLAG_FRESHEST;
 530         if (!X509_EXTENSION_get_critical(ex))
 531             continue;
 532         if (!X509_supported_extension(ex)) {
 533             x->ex_flags |= EXFLAG_CRITICAL;
 534             break;
 535         }
 536     }
 537     x->ex_flags |= EXFLAG_SET;
 538 }
 539
 540 /*-
 541  * CA checks common to all purposes
 542  * return codes:
 543  * 0 not a CA
 544  * 1 is a CA
 545  * 2 basicConstraints absent so "maybe" a CA
 546  * 3 basicConstraints absent but self signed V1.
 547  * 4 basicConstraints absent but keyUsage present and keyCertSign asserted.
 548  */
 549
 550 static int check_ca(const X509 *x)
 551 {
 552     /* keyUsage if present should allow cert signing */
 553     if (ku_reject(x, KU_KEY_CERT_SIGN))
 554         return 0;
 555     if (x->ex_flags & EXFLAG_BCONS) {
 556         if (x->ex_flags & EXFLAG_CA)
 557             return 1;
 558         /* If basicConstraints says not a CA then say so */
 559         else
 560             return 0;
 561     } else {
 562         /* we support V1 roots for...  uh, I don't really know why. */
 563         if ((x->ex_flags & V1_ROOT) == V1_ROOT)
 564             return 3;
 565         /*
 566          * If key usage present it must have certSign so tolerate it
 567          */
 568         else if (x->ex_flags & EXFLAG_KUSAGE)
 569             return 4;
 570         /* Older certificates could have Netscape-specific CA types */
 571         else if (x->ex_flags & EXFLAG_NSCERT && x->ex_nscert & NS_ANY_CA)
 572             return 5;
 573         /* can this still be regarded a CA certificate?  I doubt it */
 574         return 0;
 575     }
 576 }
 577
 578 int X509_check_ca(X509 *x)
 579 {
 580     if (!(x->ex_flags & EXFLAG_SET)) {
 581         CRYPTO_w_lock(CRYPTO_LOCK_X509);
 582         x509v3_cache_extensions(x);
 583         CRYPTO_w_unlock(CRYPTO_LOCK_X509);
 584     }
 585
 586     return check_ca(x);
 587 }
 588
 589 /* Check SSL CA: common checks for SSL client and server */
 590 static int check_ssl_ca(const X509 *x)
 591 {
 592     int ca_ret;
 593     ca_ret = check_ca(x);
 594     if (!ca_ret)
 595         return 0;
 596     /* check nsCertType if present */
 597     if (ca_ret != 5 || x->ex_nscert & NS_SSL_CA)
 598         return ca_ret;
 599     else
 600         return 0;
 601 }
 602
 603 static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x,
 604                                     int ca)
 605 {
 606     if (xku_reject(x, XKU_SSL_CLIENT))
 607         return 0;
 608     if (ca)
 609         return check_ssl_ca(x);
 610     /* We need to do digital signatures or key agreement */
 611     if (ku_reject(x, KU_DIGITAL_SIGNATURE | KU_KEY_AGREEMENT))
 612         return 0;
 613     /* nsCertType if present should allow SSL client use */
 614     if (ns_reject(x, NS_SSL_CLIENT))
 615         return 0;
 616     return 1;
 617 }
 618
 619 /*
 620  * Key usage needed for TLS/SSL server: digital signature, encipherment or
 621  * key agreement. The ssl code can check this more thoroughly for individual
 622  * key types.
 623  */
 624 #define KU_TLS \
 625         KU_DIGITAL_SIGNATURE|KU_KEY_ENCIPHERMENT|KU_KEY_AGREEMENT
 626
 627 static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x,
 628                                     int ca)
 629 {
 630     if (xku_reject(x, XKU_SSL_SERVER | XKU_SGC))
 631         return 0;
 632     if (ca)
 633         return check_ssl_ca(x);
 634
 635     if (ns_reject(x, NS_SSL_SERVER))
 636         return 0;
 637     if (ku_reject(x, KU_TLS))
 638         return 0;
 639
 640     return 1;
 641
 642 }
 643
 644 static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x,
 645                                        int ca)
 646 {
 647     int ret;
 648     ret = check_purpose_ssl_server(xp, x, ca);
 649     if (!ret || ca)
 650         return ret;
 651     /* We need to encipher or Netscape complains */
 652     if (ku_reject(x, KU_KEY_ENCIPHERMENT))
 653         return 0;
 654     return ret;
 655 }
 656
 657 /* common S/MIME checks */
 658 static int purpose_smime(const X509 *x, int ca)
 659 {
 660     if (xku_reject(x, XKU_SMIME))
 661         return 0;
 662     if (ca) {
 663         int ca_ret;
 664         ca_ret = check_ca(x);
 665         if (!ca_ret)
 666             return 0;
 667         /* check nsCertType if present */
 668         if (ca_ret != 5 || x->ex_nscert & NS_SMIME_CA)
 669             return ca_ret;
 670         else
 671             return 0;
 672     }
 673     if (x->ex_flags & EXFLAG_NSCERT) {
 674         if (x->ex_nscert & NS_SMIME)
 675             return 1;
 676         /* Workaround for some buggy certificates */
 677         if (x->ex_nscert & NS_SSL_CLIENT)
 678             return 2;
 679         return 0;
 680     }
 681     return 1;
 682 }
 683
 684 static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x,
 685                                     int ca)
 686 {
 687     int ret;
 688     ret = purpose_smime(x, ca);
 689     if (!ret || ca)
 690         return ret;
 691     if (ku_reject(x, KU_DIGITAL_SIGNATURE | KU_NON_REPUDIATION))
 692         return 0;
 693     return ret;
 694 }
 695
 696 static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x,
 697                                        int ca)
 698 {
 699     int ret;
 700     ret = purpose_smime(x, ca);
 701     if (!ret || ca)
 702         return ret;
 703     if (ku_reject(x, KU_KEY_ENCIPHERMENT))
 704         return 0;
 705     return ret;
 706 }
 707
 708 static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x,
 709                                   int ca)
 710 {
 711     if (ca) {
 712         int ca_ret;
 713         if ((ca_ret = check_ca(x)) != 2)
 714             return ca_ret;
 715         else
 716             return 0;
 717     }
 718     if (ku_reject(x, KU_CRL_SIGN))
 719         return 0;
 720     return 1;
 721 }
 722
 723 /*
 724  * OCSP helper: this is *not* a full OCSP check. It just checks that each CA
 725  * is valid. Additional checks must be made on the chain.
 726  */
 727
 728 static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca)
 729 {
 730     /*
 731      * Must be a valid CA.  Should we really support the "I don't know" value
 732      * (2)?
 733      */
 734     if (ca)
 735         return check_ca(x);
 736     /* leaf certificate is checked in OCSP_verify() */
 737     return 1;
 738 }
 739
 740 static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x,
 741                                         int ca)
 742 {
 743     int i_ext;
 744
 745     /* If ca is true we must return if this is a valid CA certificate. */
 746     if (ca)
 747         return check_ca(x);
 748
 749     /*
 750      * Check the optional key usage field:
 751      * if Key Usage is present, it must be one of digitalSignature
 752      * and/or nonRepudiation (other values are not consistent and shall
 753      * be rejected).
 754      */
 755     if ((x->ex_flags & EXFLAG_KUSAGE)
 756         && ((x->ex_kusage & ~(KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE)) ||
 757             !(x->ex_kusage & (KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE))))
 758         return 0;
 759
 760     /* Only time stamp key usage is permitted and it's required. */
 761     if (!(x->ex_flags & EXFLAG_XKUSAGE) || x->ex_xkusage != XKU_TIMESTAMP)
 762         return 0;
 763
 764     /* Extended Key Usage MUST be critical */
 765     i_ext = X509_get_ext_by_NID((X509 *)x, NID_ext_key_usage, -1);
 766     if (i_ext >= 0) {
 767         X509_EXTENSION *ext = X509_get_ext((X509 *)x, i_ext);
 768         if (!X509_EXTENSION_get_critical(ext))
 769             return 0;
 770     }
 771
 772     return 1;
 773 }
 774
 775 static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca)
 776 {
 777     return 1;
 778 }
 779
 780 /*-
 781  * Various checks to see if one certificate issued the second.
 782  * This can be used to prune a set of possible issuer certificates
 783  * which have been looked up using some simple method such as by
 784  * subject name.
 785  * These are:
 786  * 1. Check issuer_name(subject) == subject_name(issuer)
 787  * 2. If akid(subject) exists check it matches issuer
 788  * 3. If key_usage(issuer) exists check it supports certificate signing
 789  * returns 0 for OK, positive for reason for mismatch, reasons match
 790  * codes for X509_verify_cert()
 791  */
 792
 793 int X509_check_issued(X509 *issuer, X509 *subject)
 794 {
 795     if (X509_NAME_cmp(X509_get_subject_name(issuer),
 796                       X509_get_issuer_name(subject)))
 797         return X509_V_ERR_SUBJECT_ISSUER_MISMATCH;
 798     x509v3_cache_extensions(issuer);
 799     x509v3_cache_extensions(subject);
 800
 801     if (subject->akid) {
 802         int ret = X509_check_akid(issuer, subject->akid);
 803         if (ret != X509_V_OK)
 804             return ret;
 805     }
 806
 807     if (subject->ex_flags & EXFLAG_PROXY) {
 808         if (ku_reject(issuer, KU_DIGITAL_SIGNATURE))
 809             return X509_V_ERR_KEYUSAGE_NO_DIGITAL_SIGNATURE;
 810     } else if (ku_reject(issuer, KU_KEY_CERT_SIGN))
 811         return X509_V_ERR_KEYUSAGE_NO_CERTSIGN;
 812     return X509_V_OK;
 813 }
 814
 815 int X509_check_akid(X509 *issuer, AUTHORITY_KEYID *akid)
 816 {
 817
 818     if (!akid)
 819         return X509_V_OK;
 820
 821     /* Check key ids (if present) */
 822     if (akid->keyid && issuer->skid &&
 823         ASN1_OCTET_STRING_cmp(akid->keyid, issuer->skid))
 824         return X509_V_ERR_AKID_SKID_MISMATCH;
 825     /* Check serial number */
 826     if (akid->serial &&
 827         ASN1_INTEGER_cmp(X509_get_serialNumber(issuer), akid->serial))
 828         return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
 829     /* Check issuer name */
 830     if (akid->issuer) {
 831         /*
 832          * Ugh, for some peculiar reason AKID includes SEQUENCE OF
 833          * GeneralName. So look for a DirName. There may be more than one but
 834          * we only take any notice of the first.
 835          */
 836         GENERAL_NAMES *gens;
 837         GENERAL_NAME *gen;
 838         X509_NAME *nm = NULL;
 839         int i;
 840         gens = akid->issuer;
 841         for (i = 0; i < sk_GENERAL_NAME_num(gens); i++) {
 842             gen = sk_GENERAL_NAME_value(gens, i);
 843             if (gen->type == GEN_DIRNAME) {
 844                 nm = gen->d.dirn;
 845                 break;
 846             }
 847         }
 848         if (nm && X509_NAME_cmp(nm, X509_get_issuer_name(issuer)))
 849             return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH;
 850     }
 851     return X509_V_OK;
 852 }