crypto/x509v3/v3_purp.c

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