util_reauth.c

   1 /*
   2  * Copyright (c) 2010, JANET(UK)
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  *
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * 3. Neither the name of JANET(UK) nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  21  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #include "gssapiP_eap.h"
  34
  35 #include <dlfcn.h>
  36
  37 /*
  38  * Fast reauthentication support for EAP GSS.
  39  */
  40
  41 krb5_error_code
  42 krb5_encrypt_tkt_part(krb5_context, const krb5_keyblock *, krb5_ticket *);
  43
  44 krb5_error_code
  45 encode_krb5_ticket(const krb5_ticket *rep, krb5_data **code);
  46
  47 static OM_uint32
  48 gssDisplayName(OM_uint32 *minor,
  49                gss_name_t name,
  50                gss_buffer_t buffer,
  51                gss_OID *name_type);
  52
  53 static OM_uint32
  54 gssImportName(OM_uint32 *minor,
  55               gss_buffer_t buffer,
  56               gss_OID name_type,
  57               gss_name_t *name);
  58
  59 static krb5_error_code
  60 getAcceptorKey(krb5_context krbContext,
  61                gss_ctx_id_t ctx,
  62                gss_cred_id_t cred,
  63                krb5_principal *princ,
  64                krb5_keyblock *key)
  65 {
  66     krb5_error_code code;
  67     krb5_keytab keytab = NULL;
  68     krb5_keytab_entry ktent = { 0 };
  69     krb5_kt_cursor cursor = NULL;
  70
  71     *princ = NULL;
  72     memset(key, 0, sizeof(*key));
  73
  74     code = krb5_kt_default(krbContext, &keytab);
  75     if (code != 0)
  76         goto cleanup;
  77
  78     if (cred != GSS_C_NO_CREDENTIAL && cred->name != GSS_C_NO_NAME) {
  79         code = krb5_kt_get_entry(krbContext, keytab,
  80                                  cred->name->krbPrincipal, 0,
  81                                  ctx->encryptionType, &ktent);
  82         if (code != 0)
  83             goto cleanup;
  84     } else {
  85         /*
  86          * It's not clear that looking encrypting the ticket in the
  87          * requested EAP enctype provides any value.
  88          */
  89         code = krb5_kt_start_seq_get(krbContext, keytab, &cursor);
  90         if (code != 0)
  91             goto cleanup;
  92
  93         while ((code = krb5_kt_next_entry(krbContext, keytab,
  94                                           &ktent, &cursor)) == 0) {
  95             if (ktent.key.enctype == ctx->encryptionType)
  96                 break;
  97             else
  98                 krb5_free_keytab_entry_contents(krbContext, &ktent);
  99         }
 100     }
 101
 102     if (code == 0) {
 103         *princ = ktent.principal;
 104         *key = ktent.key;
 105     }
 106
 107 cleanup:
 108     if (cred == GSS_C_NO_CREDENTIAL || cred->name == GSS_C_NO_NAME)
 109         krb5_kt_end_seq_get(krbContext, keytab, &cursor);
 110     krb5_kt_close(krbContext, keytab);
 111
 112     if (code != 0)
 113         krb5_free_keytab_entry_contents(krbContext, &ktent);
 114
 115     return code;
 116 }
 117
 118 static OM_uint32
 119 freezeAttrContext(OM_uint32 *minor,
 120                   gss_name_t initiatorName,
 121                   krb5_const_principal acceptorPrinc,
 122                   krb5_keyblock *session,
 123                   krb5_authdata ***authdata)
 124 {
 125     OM_uint32 major, tmpMinor;
 126     krb5_error_code code;
 127     gss_buffer_desc attrBuf = GSS_C_EMPTY_BUFFER;
 128     krb5_authdata *authData[2], authDatum = { 0 };
 129     krb5_context krbContext;
 130
 131     GSSEAP_KRB_INIT(&krbContext);
 132
 133     major = gssEapExportAttrContext(minor, initiatorName, &attrBuf);
 134     if (GSS_ERROR(major))
 135         return major;
 136
 137     authDatum.ad_type = KRB5_AUTHDATA_RADIUS_AVP;
 138     authDatum.length = attrBuf.length;
 139     authDatum.contents = attrBuf.value;
 140     authData[0] = &authDatum;
 141     authData[1] = NULL;
 142
 143     code = krb5_make_authdata_kdc_issued(krbContext, session, acceptorPrinc,
 144                                          authData, authdata);
 145     if (code != 0) {
 146         major = GSS_S_FAILURE;
 147         *minor = code;
 148     } else {
 149         major = GSS_S_COMPLETE;
 150     }
 151
 152     gss_release_buffer(&tmpMinor, &attrBuf);
 153
 154     return major;
 155 }
 156
 157 /*
 158  * Fabricate a ticket to ourselves given a GSS EAP context.
 159  */
 160 OM_uint32
 161 gssEapMakeReauthCreds(OM_uint32 *minor,
 162                       gss_ctx_id_t ctx,
 163                       gss_cred_id_t cred,
 164                       gss_buffer_t credBuf)
 165 {
 166     OM_uint32 major = GSS_S_COMPLETE;
 167     krb5_error_code code;
 168     krb5_context krbContext = NULL;
 169     krb5_ticket ticket = { 0 };
 170     krb5_keyblock session = { 0 }, acceptorKey = { 0 };
 171     krb5_enc_tkt_part enc_part = { 0 };
 172     krb5_data *ticketData = NULL, *credsData = NULL;
 173     krb5_creds creds = { 0 };
 174     krb5_auth_context authContext = NULL;
 175
 176     credBuf->length = 0;
 177     credBuf->value = NULL;
 178
 179     GSSEAP_KRB_INIT(&krbContext);
 180
 181     code = getAcceptorKey(krbContext, ctx, cred,
 182                           &ticket.server, &acceptorKey);
 183     if (code == KRB5_KT_NOTFOUND) {
 184         gss_buffer_desc emptyToken = { 0, "" };
 185
 186         /*
 187          * If we can't produce the KRB-CRED message, we need to
 188          * return an empty (not NULL) token to the caller so we
 189          * don't change the number of authentication legs.
 190          */
 191         return duplicateBuffer(minor, &emptyToken, credBuf);
 192     } else if (code != 0)
 193         goto cleanup;
 194
 195     enc_part.flags = TKT_FLG_INITIAL;
 196
 197     /*
 198      * Generate a random session key to place in the ticket and
 199      * sign the "KDC-Issued" authorization data element.
 200      */
 201     code = krb5_c_make_random_key(krbContext, ctx->encryptionType,
 202                                   &session);
 203     if (code != 0)
 204         goto cleanup;
 205
 206     enc_part.session = &session;
 207     enc_part.client = ctx->initiatorName->krbPrincipal;
 208     enc_part.times.authtime = time(NULL);
 209     enc_part.times.starttime = enc_part.times.authtime;
 210     enc_part.times.endtime = ctx->expiryTime
 211                              ? ctx->expiryTime
 212                              : KRB5_INT32_MAX;
 213     enc_part.times.renew_till = 0;
 214
 215     major = freezeAttrContext(minor, ctx->initiatorName, ticket.server,
 216                               &session, &enc_part.authorization_data);
 217     if (GSS_ERROR(major))
 218         goto cleanup;
 219
 220     ticket.enc_part2 = &enc_part;
 221
 222     code = krb5_encrypt_tkt_part(krbContext, &acceptorKey, &ticket);
 223     if (code != 0)
 224         goto cleanup;
 225
 226     code = encode_krb5_ticket(&ticket, &ticketData);
 227     if (code != 0)
 228         goto cleanup;
 229
 230     creds.client = enc_part.client;
 231     creds.server = ticket.server;
 232     creds.keyblock = session;
 233     creds.times = enc_part.times;
 234     creds.ticket_flags = enc_part.flags;
 235     creds.ticket = *ticketData;
 236     creds.authdata = enc_part.authorization_data;
 237
 238     code = krb5_auth_con_init(krbContext, &authContext);
 239     if (code != 0)
 240         goto cleanup;
 241
 242     code = krb5_auth_con_setflags(krbContext, authContext, 0);
 243     if (code != 0)
 244         goto cleanup;
 245
 246     code = krb5_auth_con_setsendsubkey(krbContext, authContext,
 247                                        &ctx->rfc3961Key);
 248     if (code != 0)
 249         goto cleanup;
 250
 251     code = krb5_mk_1cred(krbContext, authContext, &creds, &credsData, NULL);
 252     if (code != 0)
 253         goto cleanup;
 254
 255     krbDataToGssBuffer(credsData, credBuf);
 256
 257 cleanup:
 258     if (ticket.enc_part.ciphertext.data != NULL)
 259         GSSEAP_FREE(ticket.enc_part.ciphertext.data);
 260     krb5_free_keyblock_contents(krbContext, &session);
 261     krb5_free_keyblock_contents(krbContext, &acceptorKey);
 262     krb5_free_data(krbContext, ticketData);
 263     krb5_auth_con_free(krbContext, authContext);
 264     krb5_free_authdata(krbContext, enc_part.authorization_data);
 265     if (credsData != NULL)
 266         GSSEAP_FREE(credsData);
 267
 268     if (major == GSS_S_COMPLETE) {
 269         *minor = code;
 270         major = code != 0 ? GSS_S_FAILURE : GSS_S_COMPLETE;
 271     }
 272
 273     return major;
 274 }
 275
 276 static int
 277 isTicketGrantingServiceP(krb5_context krbContext,
 278                          krb5_const_principal principal)
 279 {
 280     if (krb5_princ_size(krbContext, principal) == 2 &&
 281         krb5_princ_component(krbContext, principal, 0)->length == 6 &&
 282         memcmp(krb5_princ_component(krbContext,
 283                                     principal, 0)->data, "krbtgt", 6) == 0)
 284         return TRUE;
 285
 286     return FALSE;
 287 }
 288
 289 /*
 290  * Store re-authentication (Kerberos) credentials in a credential handle.
 291  */
 292 OM_uint32
 293 gssEapStoreReauthCreds(OM_uint32 *minor,
 294                        gss_ctx_id_t ctx,
 295                        gss_cred_id_t cred,
 296                        gss_buffer_t credBuf)
 297 {
 298     OM_uint32 major = GSS_S_COMPLETE, code;
 299     krb5_context krbContext = NULL;
 300     krb5_auth_context authContext = NULL;
 301     krb5_data credData = { 0 };
 302     krb5_creds **creds = NULL;
 303     krb5_principal canonPrinc;
 304     int i;
 305
 306     if (credBuf->length == 0 || cred == GSS_C_NO_CREDENTIAL)
 307         return GSS_S_COMPLETE;
 308
 309     GSSEAP_KRB_INIT(&krbContext);
 310
 311     code = krb5_auth_con_init(krbContext, &authContext);
 312     if (code != 0)
 313         goto cleanup;
 314
 315     code = krb5_auth_con_setflags(krbContext, authContext, 0);
 316     if (code != 0)
 317         goto cleanup;
 318
 319     code = krb5_auth_con_setrecvsubkey(krbContext, authContext,
 320                                        &ctx->rfc3961Key);
 321     if (code != 0)
 322         goto cleanup;
 323
 324     gssBufferToKrbData(credBuf, &credData);
 325
 326     code = krb5_rd_cred(krbContext, authContext, &credData, &creds, NULL);
 327     if (code != 0)
 328         goto cleanup;
 329
 330     if (creds == NULL || creds[0] == NULL)
 331         goto cleanup;
 332
 333     code = krb5_copy_principal(krbContext, creds[0]->client, &canonPrinc);
 334     if (code != 0)
 335         goto cleanup;
 336
 337     krb5_free_principal(krbContext, cred->name->krbPrincipal);
 338     cred->name->krbPrincipal = canonPrinc;
 339
 340     cred->expiryTime = creds[0]->times.endtime;
 341
 342     code = krb5_cc_new_unique(krbContext, "MEMORY", NULL, &cred->krbCredCache);
 343     if (code != 0)
 344         goto cleanup;
 345
 346     code = krb5_cc_initialize(krbContext, cred->krbCredCache,
 347                               creds[0]->client);
 348     if (code != 0)
 349         goto cleanup;
 350
 351     for (i = 0; creds[i] != NULL; i++) {
 352         krb5_creds kcred = *(creds[i]);
 353
 354         /*
 355          * Swap in the acceptor name the client asked for so
 356          * get_credentials() works. We're making the assumption that
 357          * any service tickets returned are for us. We'll need to
 358          * reflect some more on whether that is a safe assumption.
 359          */
 360         if (!isTicketGrantingServiceP(krbContext, kcred.server))
 361             kcred.server = ctx->acceptorName->krbPrincipal;
 362
 363         code = krb5_cc_store_cred(krbContext, cred->krbCredCache, &kcred);
 364         if (code != 0)
 365             goto cleanup;
 366     }
 367
 368 #ifdef HAVE_GSS_KRB5_IMPORT_CRED
 369     /*
 370      * To turn a credentials cache into a GSS credentials handle, we
 371      * require the gss_krb5_import_cred() API (present in Heimdal, but
 372      * not shipped in MIT yet).
 373      */
 374     major = gss_krb5_import_cred(minor, cred->krbCredCache, NULL, NULL,
 375                                  &cred->krbCred);
 376     if (GSS_ERROR(major))
 377         goto cleanup;
 378 #else
 379 #warning Missing gss_krb5_import_cred() implementation
 380 #endif
 381
 382 cleanup:
 383     *minor = code;
 384
 385     krb5_auth_con_free(krbContext, authContext);
 386     if (creds != NULL) {
 387         for (i = 0; creds[i] != NULL; i++)
 388             krb5_free_creds(krbContext, creds[i]);
 389     }
 390     if (major == GSS_S_COMPLETE)
 391         major = *minor ? GSS_S_FAILURE : GSS_S_COMPLETE;
 392
 393     return major;
 394 }
 395
 396 static gss_buffer_desc radiusAvpKrbAttr = {
 397     sizeof("urn:authdata-radius-avp") - 1, "urn:authdata-radius-avp"
 398 };
 399
 400 /*
 401  * Unfortunately extracting an AD-KDCIssued authorization data element
 402  * is pretty implementation-dependent. It's not possible to verify the
 403  * signature ourselves because the ticket session key is not exposed
 404  * outside GSS. In an ideal world, all AD-KDCIssued elements would be
 405  * verified by the Kerberos library and authentication would fail if
 406  * verification failed. We're not quite there yet and as a result have
 407  * to go through some hoops to get this to work. The alternative would
 408  * be to sign the authorization data with our long-term key, but it
 409  * seems a pity to compromise the design because of current implementation
 410  * limitations.
 411  *
 412  * (Specifically, the hoops involve a libkrb5 authorisation data plugin
 413  * that exposes the verified and serialised attribute context through
 414  * the Kerberos GSS mechanism's naming extensions API.)
 415  */
 416 static OM_uint32
 417 defrostAttrContext(OM_uint32 *minor,
 418                    gss_name_t glueName,
 419                    gss_name_t mechName)
 420 {
 421     OM_uint32 major, tmpMinor;
 422     gss_buffer_desc authData = GSS_C_EMPTY_BUFFER;
 423     gss_buffer_desc authDataDisplay = GSS_C_EMPTY_BUFFER;
 424     int more = -1;
 425     int authenticated, complete;
 426
 427     major = gssGetNameAttribute(minor, glueName, &radiusAvpKrbAttr,
 428                                 &authenticated, &complete,
 429                                 &authData, &authDataDisplay, &more);
 430     if (major == GSS_S_COMPLETE) {
 431         if (authenticated == 0)
 432             major = GSS_S_BAD_NAME;
 433         else
 434             major = gssEapImportAttrContext(minor, &authData, mechName);
 435     } else if (major == GSS_S_UNAVAILABLE) {
 436         major = GSS_S_COMPLETE;
 437     }
 438
 439     gss_release_buffer(&tmpMinor, &authData);
 440     gss_release_buffer(&tmpMinor, &authDataDisplay);
 441
 442     return major;
 443 }
 444
 445 /*
 446  * Convert a mechanism glue to an EAP mechanism name by displaying and
 447  * importing it. This also handles the RADIUS attributes.
 448  */
 449 OM_uint32
 450 gssEapGlueToMechName(OM_uint32 *minor,
 451                      gss_name_t glueName,
 452                      gss_name_t *pMechName)
 453 {
 454     OM_uint32 major, tmpMinor;
 455     gss_buffer_desc nameBuf = GSS_C_EMPTY_BUFFER;
 456
 457     *pMechName = GSS_C_NO_NAME;
 458
 459     major = gssDisplayName(minor, glueName, &nameBuf, NULL);
 460     if (GSS_ERROR(major))
 461         goto cleanup;
 462
 463     major = gssEapImportName(minor, &nameBuf, GSS_C_NT_USER_NAME,
 464                              pMechName);
 465     if (GSS_ERROR(major))
 466         goto cleanup;
 467
 468     major = defrostAttrContext(minor, glueName, *pMechName);
 469     if (GSS_ERROR(major))
 470         goto cleanup;
 471
 472 cleanup:
 473     if (GSS_ERROR(major)) {
 474         gssReleaseName(&tmpMinor, pMechName);
 475         *pMechName = GSS_C_NO_NAME;
 476     }
 477
 478     gss_release_buffer(&tmpMinor, &nameBuf);
 479
 480     return major;
 481 }
 482
 483 /*
 484  * Convert an EAP mechanism name to a mechanism glue name by displaying
 485  * and importing it.
 486  */
 487 OM_uint32
 488 gssEapMechToGlueName(OM_uint32 *minor,
 489                      gss_name_t mechName,
 490                      gss_name_t *pGlueName)
 491 {
 492     OM_uint32 major, tmpMinor;
 493     gss_buffer_desc nameBuf = GSS_C_EMPTY_BUFFER;
 494
 495     *pGlueName = GSS_C_NO_NAME;
 496
 497     major = gssEapDisplayName(minor, mechName, &nameBuf, NULL);
 498     if (GSS_ERROR(major))
 499         goto cleanup;
 500
 501     major = gssImportName(minor, &nameBuf, GSS_C_NT_USER_NAME,
 502                           pGlueName);
 503     if (GSS_ERROR(major))
 504         goto cleanup;
 505
 506 cleanup:
 507     gss_release_buffer(&tmpMinor, &nameBuf);
 508
 509     return major;
 510 }
 511
 512 /*
 513  * Suck out the analgous elements of a Kerberos GSS context into an EAP
 514  * one so that the application doesn't know the difference.
 515  */
 516 OM_uint32
 517 gssEapReauthComplete(OM_uint32 *minor,
 518                     gss_ctx_id_t ctx,
 519                     gss_cred_id_t cred,
 520                     const gss_OID mech,
 521                     OM_uint32 timeRec)
 522 {
 523     OM_uint32 major, tmpMinor;
 524     gss_buffer_set_t keyData = GSS_C_NO_BUFFER_SET;
 525
 526     if (!oidEqual(mech, gss_mech_krb5)) {
 527         major = GSS_S_BAD_MECH;
 528         goto cleanup;
 529     }
 530
 531     /* Get the raw subsession key and encryption type*/
 532     major = gssInquireSecContextByOid(minor, ctx->kerberosCtx,
 533                                       GSS_C_INQ_SSPI_SESSION_KEY, &keyData);
 534     if (GSS_ERROR(major))
 535         goto cleanup;
 536
 537     {
 538         gss_OID_desc oid;
 539         int suffix;
 540
 541         oid.length = keyData->elements[1].length;
 542         oid.elements = keyData->elements[1].value;
 543
 544         /* GSS_KRB5_SESSION_KEY_ENCTYPE_OID */
 545         major = decomposeOid(minor,
 546                              "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02\x04",
 547                              10, &oid, &suffix);
 548         if (GSS_ERROR(major))
 549             goto cleanup;
 550
 551         ctx->encryptionType = suffix;
 552     }
 553
 554     {
 555         krb5_context krbContext = NULL;
 556         krb5_keyblock key;
 557
 558         GSSEAP_KRB_INIT(&krbContext);
 559
 560         KRB_KEY_LENGTH(&key) = keyData->elements[0].length;
 561         KRB_KEY_DATA(&key)   = keyData->elements[0].value;
 562         KRB_KEY_TYPE(&key)   = ctx->encryptionType;
 563
 564         *minor = krb5_copy_keyblock_contents(krbContext,
 565                                              &key, &ctx->rfc3961Key);
 566         if (*minor != 0) {
 567             major = GSS_S_FAILURE;
 568             goto cleanup;
 569         }
 570     }
 571
 572     major = rfc3961ChecksumTypeForKey(minor, &ctx->rfc3961Key,
 573                                       &ctx->checksumType);
 574     if (GSS_ERROR(major))
 575         goto cleanup;
 576
 577     if (timeRec != GSS_C_INDEFINITE)
 578         ctx->expiryTime = time(NULL) + timeRec;
 579
 580     /* Initialize our sequence state */
 581     major = sequenceInit(minor,
 582                          &ctx->seqState, ctx->recvSeq,
 583                          ((ctx->gssFlags & GSS_C_REPLAY_FLAG) != 0),
 584                          ((ctx->gssFlags & GSS_C_SEQUENCE_FLAG) != 0),
 585                          TRUE);
 586     if (GSS_ERROR(major))
 587         goto cleanup;
 588
 589     major = GSS_S_COMPLETE;
 590
 591 cleanup:
 592     gss_release_buffer_set(&tmpMinor, &keyData);
 593
 594     return major;
 595 }
 596
 597 /*
 598  * The remainder of this file consists of wrappers so we can call into the
 599  * mechanism glue without calling ourselves.
 600  */
 601 static OM_uint32
 602 (*gssInitSecContextNext)(OM_uint32 *,
 603                          gss_cred_id_t,
 604                          gss_ctx_id_t *,
 605                          gss_name_t,
 606                          gss_OID,
 607                          OM_uint32,
 608                          OM_uint32,
 609                          gss_channel_bindings_t,
 610                          gss_buffer_t,
 611                          gss_OID *,
 612                          gss_buffer_t,
 613                          OM_uint32 *,
 614                          OM_uint32 *);
 615
 616 static OM_uint32
 617 (*gssAcceptSecContextNext)(OM_uint32 *,
 618                            gss_ctx_id_t *,
 619                            gss_cred_id_t,
 620                            gss_buffer_t,
 621                            gss_channel_bindings_t,
 622                            gss_name_t *,
 623                            gss_OID *,
 624                            gss_buffer_t,
 625                            OM_uint32 *,
 626                            OM_uint32 *,
 627                            gss_cred_id_t *);
 628
 629 static OM_uint32
 630 (*gssReleaseCredNext)(OM_uint32 *, gss_cred_id_t *);
 631
 632 static OM_uint32
 633 (*gssReleaseNameNext)(OM_uint32 *, gss_name_t *);
 634
 635 static OM_uint32
 636 (*gssInquireSecContextByOidNext)(OM_uint32 *,
 637                                  const gss_ctx_id_t,
 638                                  const gss_OID,
 639                                  gss_buffer_set_t *);
 640
 641 static OM_uint32
 642 (*gssDeleteSecContextNext)(OM_uint32 *,
 643                           gss_ctx_id_t *,
 644                           gss_buffer_t);
 645
 646 static OM_uint32
 647 (*gssDisplayNameNext)(OM_uint32 *,
 648                       gss_name_t,
 649                       gss_buffer_t,
 650                       gss_OID *);
 651
 652 static OM_uint32
 653 (*gssImportNameNext)(OM_uint32 *,
 654                      gss_buffer_t,
 655                      gss_OID,
 656                      gss_name_t *);
 657
 658 static OM_uint32
 659 (*gssStoreCredNext)(OM_uint32 *,
 660                     const gss_cred_id_t,
 661                     gss_cred_usage_t,
 662                     const gss_OID,
 663                     OM_uint32,
 664                     OM_uint32,
 665                     gss_OID_set *,
 666                     gss_cred_usage_t *);
 667
 668 static OM_uint32
 669 (*gssGetNameAttributeNext)(OM_uint32 *,
 670                           gss_name_t,
 671                           gss_buffer_t,
 672                           int *,
 673                           int *,
 674                           gss_buffer_t,
 675                           gss_buffer_t,
 676                           int *);
 677
 678 #define NEXT_SYMBOL(local, global)  ((local) = dlsym(RTLD_NEXT, (global)))
 679
 680 OM_uint32
 681 gssEapReauthInitialize(OM_uint32 *minor)
 682 {
 683     NEXT_SYMBOL(gssInitSecContextNext,         "gss_init_sec_context");
 684     NEXT_SYMBOL(gssAcceptSecContextNext,       "gss_accept_sec_context");
 685     NEXT_SYMBOL(gssReleaseCredNext,            "gss_release_cred");
 686     NEXT_SYMBOL(gssReleaseNameNext,            "gss_release_name");
 687     NEXT_SYMBOL(gssInquireSecContextByOidNext, "gss_inquire_sec_context_by_oid");
 688     NEXT_SYMBOL(gssDeleteSecContextNext,       "gss_delete_sec_context");
 689     NEXT_SYMBOL(gssDisplayNameNext,            "gss_display_name");
 690     NEXT_SYMBOL(gssImportNameNext,             "gss_import_name");
 691     NEXT_SYMBOL(gssStoreCredNext,              "gss_store_cred");
 692     NEXT_SYMBOL(gssGetNameAttributeNext,       "gss_get_name_attribute");
 693
 694     return GSS_S_COMPLETE;
 695 }
 696
 697 OM_uint32
 698 gssInitSecContext(OM_uint32 *minor,
 699                   gss_cred_id_t cred,
 700                   gss_ctx_id_t *context_handle,
 701                   gss_name_t target_name,
 702                   gss_OID mech_type,
 703                   OM_uint32 req_flags,
 704                   OM_uint32 time_req,
 705                   gss_channel_bindings_t input_chan_bindings,
 706                   gss_buffer_t input_token,
 707                   gss_OID *actual_mech_type,
 708                   gss_buffer_t output_token,
 709                   OM_uint32 *ret_flags,
 710                   OM_uint32 *time_rec)
 711 {
 712     if (gssInitSecContextNext == NULL)
 713         return GSS_S_UNAVAILABLE;
 714
 715     return gssInitSecContextNext(minor, cred, context_handle,
 716                                  target_name, mech_type, req_flags,
 717                                  time_req, input_chan_bindings,
 718                                  input_token, actual_mech_type,
 719                                  output_token, ret_flags, time_rec);
 720 }
 721
 722 OM_uint32
 723 gssAcceptSecContext(OM_uint32 *minor,
 724                     gss_ctx_id_t *context_handle,
 725                     gss_cred_id_t cred,
 726                     gss_buffer_t input_token,
 727                     gss_channel_bindings_t input_chan_bindings,
 728                     gss_name_t *src_name,
 729                     gss_OID *mech_type,
 730                     gss_buffer_t output_token,
 731                     OM_uint32 *ret_flags,
 732                     OM_uint32 *time_rec,
 733                     gss_cred_id_t *delegated_cred_handle)
 734 {
 735     if (gssAcceptSecContextNext == NULL)
 736         return GSS_S_UNAVAILABLE;
 737
 738     return gssAcceptSecContextNext(minor, context_handle, cred,
 739                                    input_token, input_chan_bindings,
 740                                    src_name, mech_type, output_token,
 741                                    ret_flags, time_rec, delegated_cred_handle);
 742 }
 743
 744 OM_uint32
 745 gssReleaseCred(OM_uint32 *minor,
 746                gss_cred_id_t *cred_handle)
 747 {
 748     if (gssReleaseCredNext == NULL)
 749         return GSS_S_UNAVAILABLE;
 750
 751     return gssReleaseCredNext(minor, cred_handle);
 752 }
 753
 754 OM_uint32
 755 gssReleaseName(OM_uint32 *minor,
 756                gss_name_t *name)
 757 {
 758     if (gssReleaseName == NULL)
 759         return GSS_S_UNAVAILABLE;
 760
 761     return gssReleaseNameNext(minor, name);
 762 }
 763
 764 OM_uint32
 765 gssDeleteSecContext(OM_uint32 *minor,
 766                     gss_ctx_id_t *context_handle,
 767                     gss_buffer_t output_token)
 768 {
 769     if (gssDeleteSecContextNext == NULL)
 770         return GSS_S_UNAVAILABLE;
 771
 772     return gssDeleteSecContextNext(minor, context_handle, output_token);
 773 }
 774
 775 static OM_uint32
 776 gssDisplayName(OM_uint32 *minor,
 777                gss_name_t name,
 778                gss_buffer_t buffer,
 779                gss_OID *name_type)
 780 {
 781     if (gssDisplayNameNext == NULL)
 782         return GSS_S_UNAVAILABLE;
 783
 784     return gssDisplayNameNext(minor, name, buffer, name_type);
 785 }
 786
 787 static OM_uint32
 788 gssImportName(OM_uint32 *minor,
 789               gss_buffer_t buffer,
 790               gss_OID name_type,
 791               gss_name_t *name)
 792 {
 793     if (gssImportNameNext == NULL)
 794         return GSS_S_UNAVAILABLE;
 795
 796     return gssImportNameNext(minor, buffer, name_type, name);
 797 }
 798
 799 OM_uint32
 800 gssInquireSecContextByOid(OM_uint32 *minor,
 801                           const gss_ctx_id_t context_handle,
 802                           const gss_OID desired_object,
 803                           gss_buffer_set_t *data_set)
 804 {
 805     if (gssInquireSecContextByOidNext == NULL)
 806         return GSS_S_UNAVAILABLE;
 807
 808     return gssInquireSecContextByOidNext(minor, context_handle,
 809                                          desired_object, data_set);
 810 }
 811
 812 OM_uint32
 813 gssStoreCred(OM_uint32 *minor,
 814              const gss_cred_id_t input_cred_handle,
 815              gss_cred_usage_t input_usage,
 816              const gss_OID desired_mech,
 817              OM_uint32 overwrite_cred,
 818              OM_uint32 default_cred,
 819              gss_OID_set *elements_stored,
 820              gss_cred_usage_t *cred_usage_stored)
 821 {
 822     if (gssStoreCredNext == NULL)
 823         return GSS_S_UNAVAILABLE;
 824
 825     return gssStoreCredNext(minor, input_cred_handle, input_usage,
 826                             desired_mech, overwrite_cred, default_cred,
 827                             elements_stored, cred_usage_stored);
 828 }
 829
 830 OM_uint32
 831 gssGetNameAttribute(OM_uint32 *minor,
 832                     gss_name_t name,
 833                     gss_buffer_t attr,
 834                     int *authenticated,
 835                     int *complete,
 836                     gss_buffer_t value,
 837                     gss_buffer_t display_value,
 838                     int *more)
 839 {
 840     if (gssGetNameAttributeNext == NULL)
 841         return GSS_S_UNAVAILABLE;
 842
 843     return gssGetNameAttributeNext(minor, name, attr, authenticated, complete,
 844                                    value, display_value, more);
 845 }