mech_eap/util_reauth.c

   1 /*
   2  * Copyright (c) 2011, 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 /*
  34  * Fast reauthentication support.
  35  */
  36
  37 #include "gssapiP_eap.h"
  38
  39 #include <dlfcn.h>
  40
  41 /*
  42  * Fast reauthentication support for EAP GSS.
  43  */
  44
  45 krb5_error_code
  46 krb5_encrypt_tkt_part(krb5_context, const krb5_keyblock *, krb5_ticket *);
  47
  48 krb5_error_code
  49 encode_krb5_ticket(const krb5_ticket *rep, krb5_data **code);
  50
  51 static OM_uint32
  52 gssDisplayName(OM_uint32 *minor,
  53                gss_name_t name,
  54                gss_buffer_t buffer,
  55                gss_OID *name_type);
  56
  57 static OM_uint32
  58 gssImportName(OM_uint32 *minor,
  59               gss_buffer_t buffer,
  60               gss_OID name_type,
  61               gss_name_t *name);
  62
  63 static krb5_error_code
  64 getAcceptorKey(krb5_context krbContext,
  65                gss_ctx_id_t ctx,
  66                gss_cred_id_t cred,
  67                krb5_principal *princ,
  68                krb5_keyblock *key)
  69 {
  70     krb5_error_code code;
  71     krb5_keytab keytab = NULL;
  72     krb5_keytab_entry ktent = { 0 };
  73     krb5_kt_cursor cursor;
  74
  75     *princ = NULL;
  76     memset(key, 0, sizeof(*key));
  77     memset(&cursor, 0, sizeof(cursor));
  78
  79     code = krb5_kt_default(krbContext, &keytab);
  80     if (code != 0)
  81         goto cleanup;
  82
  83     if (cred != GSS_C_NO_CREDENTIAL && cred->name != GSS_C_NO_NAME) {
  84         code = krb5_kt_get_entry(krbContext, keytab,
  85                                  cred->name->krbPrincipal, 0,
  86                                  ctx->encryptionType, &ktent);
  87         if (code != 0)
  88             goto cleanup;
  89     } else {
  90         /*
  91          * It's not clear that looking encrypting the ticket in the
  92          * requested EAP enctype provides any value.
  93          */
  94         code = krb5_kt_start_seq_get(krbContext, keytab, &cursor);
  95         if (code != 0)
  96             goto cleanup;
  97
  98         while ((code = krb5_kt_next_entry(krbContext, keytab,
  99                                           &ktent, &cursor)) == 0) {
 100             if (KRB_KEY_TYPE(KRB_KT_ENT_KEYBLOCK(&ktent)) == ctx->encryptionType)
 101                 break;
 102             else
 103                 KRB_KT_ENT_FREE(krbContext, &ktent);
 104         }
 105     }
 106
 107     if (code == 0) {
 108         *princ = ktent.principal;
 109         *key = *KRB_KT_ENT_KEYBLOCK(&ktent);
 110     }
 111
 112 cleanup:
 113     if (cred == GSS_C_NO_CREDENTIAL || cred->name == GSS_C_NO_NAME)
 114         krb5_kt_end_seq_get(krbContext, keytab, &cursor);
 115     krb5_kt_close(krbContext, keytab);
 116     if (code != 0)
 117         KRB_KT_ENT_FREE(krbContext, &ktent);
 118
 119     return code;
 120 }
 121
 122 static OM_uint32
 123 freezeAttrContext(OM_uint32 *minor,
 124                   gss_name_t initiatorName,
 125                   krb5_const_principal acceptorPrinc,
 126                   krb5_keyblock *session,
 127 #ifdef HAVE_HEIMDAL_VERSION
 128                   krb5_authdata *kdcIssuedAuthData
 129 #else
 130                   krb5_authdata ***kdcIssuedAuthData
 131 #endif
 132                   )
 133 {
 134     OM_uint32 major, tmpMinor;
 135     krb5_error_code code;
 136     krb5_context krbContext;
 137     gss_buffer_desc attrBuf = GSS_C_EMPTY_BUFFER;
 138 #ifdef HAVE_HEIMDAL_VERSION
 139     krb5_authdata authDataBuf, *authData = &authDataBuf;
 140     AuthorizationDataElement authDatum = { 0 };
 141 #else
 142     krb5_authdata *authData[2], authDatum = { 0 };
 143 #endif
 144
 145     memset(kdcIssuedAuthData, 0, sizeof(*kdcIssuedAuthData));
 146
 147     GSSEAP_KRB_INIT(&krbContext);
 148
 149     major = gssEapExportAttrContext(minor, initiatorName, &attrBuf);
 150     if (GSS_ERROR(major))
 151         return major;
 152
 153     authDatum.ad_type = KRB5_AUTHDATA_RADIUS_AVP;
 154 #ifdef HAVE_HEIMDAL_VERSION
 155     authDatum.ad_data.length = attrBuf.length;
 156     authDatum.ad_data.data = attrBuf.value;
 157     authData->len = 1;
 158     authData->val = &authDatum;
 159 #else
 160     authDatum.length = attrBuf.length;
 161     authDatum.contents = attrBuf.value;
 162     authData[0] = &authDatum;
 163     authData[1] = NULL;
 164 #endif
 165
 166     code = krbMakeAuthDataKdcIssued(krbContext, session, acceptorPrinc,
 167                                     authData, kdcIssuedAuthData);
 168     if (code != 0) {
 169         major = GSS_S_FAILURE;
 170         *minor = code;
 171     } else {
 172         major = GSS_S_COMPLETE;
 173     }
 174
 175     gss_release_buffer(&tmpMinor, &attrBuf);
 176
 177     return major;
 178 }
 179
 180 /*
 181  * Fabricate a ticket to ourselves given a GSS EAP context.
 182  */
 183 OM_uint32
 184 gssEapMakeReauthCreds(OM_uint32 *minor,
 185                       gss_ctx_id_t ctx,
 186                       gss_cred_id_t cred,
 187                       gss_buffer_t credBuf)
 188 {
 189     OM_uint32 major = GSS_S_COMPLETE;
 190     krb5_error_code code;
 191     krb5_context krbContext = NULL;
 192     krb5_keyblock session = { 0 }, acceptorKey = { 0 };
 193     krb5_principal server = NULL;
 194 #ifdef HAVE_HEIMDAL_VERSION
 195     Ticket ticket;
 196     EncTicketPart enc_part;
 197     AuthorizationData authData = { 0 };
 198     krb5_crypto krbCrypto = NULL;
 199     krb5_data ticketData = { 0 };
 200     krb5_data encPartData = { 0 };
 201     size_t len;
 202 #else
 203     krb5_ticket ticket;
 204     krb5_enc_tkt_part enc_part;
 205     krb5_data *ticketData = NULL;
 206 #endif
 207     krb5_data credsData = { 0 };
 208     krb5_creds creds = { 0 };
 209     krb5_auth_context authContext = NULL;
 210
 211     memset(&ticket, 0, sizeof(ticket));
 212     memset(&enc_part, 0, sizeof(enc_part));
 213
 214     credBuf->length = 0;
 215     credBuf->value = NULL;
 216
 217     if (ctx->acceptorName == GSS_C_NO_NAME) {
 218         *minor = GSSEAP_NO_ACCEPTOR_NAME;
 219         return GSS_S_UNAVAILABLE;
 220     }
 221
 222     GSSEAP_KRB_INIT(&krbContext);
 223
 224     code = getAcceptorKey(krbContext, ctx, cred, &server, &acceptorKey);
 225     if (code != 0) {
 226         *minor = code;
 227         return GSS_S_UNAVAILABLE;
 228     }
 229
 230     /*
 231      * Generate a random session key to place in the ticket and
 232      * sign the "KDC-Issued" authorization data element.
 233      */
 234 #ifdef HAVE_HEIMDAL_VERSION
 235     ticket.realm = server->realm;
 236     ticket.sname = server->name;
 237
 238     code = krb5_generate_random_keyblock(krbContext, ctx->encryptionType,
 239                                          &session);
 240     if (code != 0)
 241         goto cleanup;
 242
 243     enc_part.flags.initial = 1;
 244     enc_part.key = session;
 245     enc_part.crealm = ctx->initiatorName->krbPrincipal->realm;
 246     enc_part.cname = ctx->initiatorName->krbPrincipal->name;
 247     enc_part.authtime = time(NULL);
 248     enc_part.starttime = &enc_part.authtime;
 249     enc_part.endtime = (ctx->expiryTime != 0)
 250                        ? ctx->expiryTime : KRB_TIME_FOREVER;
 251     enc_part.renew_till = NULL;
 252     enc_part.authorization_data = &authData;
 253
 254     major = freezeAttrContext(minor, ctx->initiatorName, server,
 255                               &session, &authData);
 256     if (GSS_ERROR(major))
 257         goto cleanup;
 258
 259     ASN1_MALLOC_ENCODE(EncTicketPart, encPartData.data, encPartData.length,
 260                        &enc_part, &len, code);
 261     if (code != 0)
 262         goto cleanup;
 263
 264     code = krb5_crypto_init(krbContext, &acceptorKey, 0, &krbCrypto);
 265     if (code != 0)
 266         goto cleanup;
 267
 268     code = krb5_encrypt_EncryptedData(krbContext,
 269                                       krbCrypto,
 270                                       KRB5_KU_TICKET,
 271                                       encPartData.data,
 272                                       encPartData.length,
 273                                       0,
 274                                       &ticket.enc_part);
 275     if (code != 0)
 276         goto cleanup;
 277
 278     ASN1_MALLOC_ENCODE(Ticket, ticketData.data, ticketData.length,
 279                        &ticket, &len, code);
 280     if (code != 0)
 281         goto cleanup;
 282 #else
 283     ticket.server = server;
 284
 285     code = krb5_c_make_random_key(krbContext, ctx->encryptionType,
 286                                   &session);
 287     if (code != 0)
 288         goto cleanup;
 289
 290     enc_part.flags = TKT_FLG_INITIAL;
 291     enc_part.session = &session;
 292     enc_part.client = ctx->initiatorName->krbPrincipal;
 293     enc_part.times.authtime = time(NULL);
 294     enc_part.times.starttime = enc_part.times.authtime;
 295     enc_part.times.endtime = (ctx->expiryTime != 0)
 296                              ? ctx->expiryTime
 297                              : KRB_TIME_FOREVER;
 298     enc_part.times.renew_till = 0;
 299
 300     major = freezeAttrContext(minor, ctx->initiatorName, server,
 301                               &session, &enc_part.authorization_data);
 302     if (GSS_ERROR(major))
 303         goto cleanup;
 304
 305     ticket.enc_part2 = &enc_part;
 306
 307     code = krb5_encrypt_tkt_part(krbContext, &acceptorKey, &ticket);
 308     if (code != 0)
 309         goto cleanup;
 310
 311     code = encode_krb5_ticket(&ticket, &ticketData);
 312     if (code != 0)
 313         goto cleanup;
 314 #endif /* HAVE_HEIMDAL_VERSION */
 315
 316     creds.client = ctx->initiatorName->krbPrincipal;
 317     creds.server = server;
 318 #ifdef HAVE_HEIMDAL_VERSION
 319     creds.session = session;
 320     creds.times.authtime = enc_part.authtime;
 321     creds.times.starttime = *enc_part.starttime;
 322     creds.times.endtime = enc_part.endtime;
 323     creds.times.renew_till = 0;
 324     creds.flags.b = enc_part.flags;
 325     creds.ticket = ticketData;
 326     creds.authdata = authData;
 327 #else
 328     creds.keyblock = session;
 329     creds.times = enc_part.times;
 330     creds.ticket_flags = enc_part.flags;
 331     creds.ticket = *ticketData;
 332     creds.authdata = enc_part.authorization_data;
 333 #endif
 334
 335     code = krb5_auth_con_init(krbContext, &authContext);
 336     if (code != 0)
 337         goto cleanup;
 338
 339     code = krb5_auth_con_setflags(krbContext, authContext, 0);
 340     if (code != 0)
 341         goto cleanup;
 342
 343 #ifdef HAVE_HEIMDAL_VERSION
 344     code = krb5_auth_con_setlocalsubkey(krbContext, authContext,
 345                                         &ctx->rfc3961Key);
 346 #else
 347     code = krb5_auth_con_setsendsubkey(krbContext, authContext,
 348                                        &ctx->rfc3961Key);
 349 #endif
 350     if (code != 0)
 351         goto cleanup;
 352
 353     code = krbMakeCred(krbContext, authContext, &creds, &credsData);
 354     if (code != 0)
 355         goto cleanup;
 356
 357     krbDataToGssBuffer(&credsData, credBuf);
 358
 359 cleanup:
 360 #ifdef HAVE_HEIMDAL_VERSION
 361     if (krbCrypto != NULL)
 362         krb5_crypto_destroy(krbContext, krbCrypto);
 363     free_AuthorizationData(&authData);
 364     free_EncryptedData(&ticket.enc_part);
 365     krb5_data_free(&ticketData);
 366     krb5_data_free(&encPartData);
 367 #else
 368     krb5_free_authdata(krbContext, enc_part.authorization_data);
 369     if (ticket.enc_part.ciphertext.data != NULL)
 370         GSSEAP_FREE(ticket.enc_part.ciphertext.data);
 371     krb5_free_data(krbContext, ticketData);
 372 #endif
 373     krb5_free_keyblock_contents(krbContext, &session);
 374     krb5_free_principal(krbContext, server);
 375     krb5_free_keyblock_contents(krbContext, &acceptorKey);
 376     krb5_auth_con_free(krbContext, authContext);
 377
 378     if (major == GSS_S_COMPLETE) {
 379         *minor = code;
 380         major = (code != 0) ? GSS_S_FAILURE : GSS_S_COMPLETE;
 381     }
 382
 383     return major;
 384 }
 385
 386 static int
 387 isTicketGrantingServiceP(krb5_context krbContext GSSEAP_UNUSED,
 388                          krb5_const_principal principal)
 389 {
 390     if (KRB_PRINC_LENGTH(principal) == 2 &&
 391 #ifdef HAVE_HEIMDAL_VERSION
 392         strcmp(KRB_PRINC_NAME(principal)[0], "krbtgt") == 0
 393 #else
 394         krb5_princ_component(krbContext, principal, 0)->length == 6 &&
 395         memcmp(krb5_princ_component(krbContext,
 396                                     principal, 0)->data, "krbtgt", 6) == 0
 397 #endif
 398         )
 399         return TRUE;
 400
 401     return FALSE;
 402 }
 403
 404 /*
 405  * Returns TRUE if the configuration variable reauth_use_ccache is
 406  * set in krb5.conf for the eap_gss application and the client realm.
 407  */
 408 static int
 409 reauthUseCredsCache(krb5_context krbContext,
 410                     krb5_principal principal)
 411 {
 412     int reauthUseCCache;
 413
 414     /* if reauth_use_ccache, use default credentials cache if ticket is for us */
 415     krb5_appdefault_boolean(krbContext, "eap_gss",
 416                             KRB_PRINC_REALM(principal),
 417                             "reauth_use_ccache", 0, &reauthUseCCache);
 418
 419     return reauthUseCCache;
 420 }
 421
 422 /*
 423  * Look in default credentials cache for reauthentication credentials,
 424  * if policy allows.
 425  */
 426 static OM_uint32
 427 getDefaultReauthCredentials(OM_uint32 *minor,
 428                             gss_cred_id_t cred,
 429                             gss_name_t target,
 430                             time_t now,
 431                             OM_uint32 timeReq)
 432 {
 433     OM_uint32 major = GSS_S_CRED_UNAVAIL;
 434     krb5_context krbContext = NULL;
 435     krb5_error_code code = 0;
 436     krb5_ccache ccache = NULL;
 437     krb5_creds match = { 0 };
 438     krb5_creds creds = { 0 };
 439
 440     GSSEAP_KRB_INIT(&krbContext);
 441
 442     GSSEAP_ASSERT(cred != GSS_C_NO_CREDENTIAL);
 443     GSSEAP_ASSERT(target != GSS_C_NO_NAME);
 444
 445     if (cred->name == GSS_C_NO_NAME ||
 446         !reauthUseCredsCache(krbContext, cred->name->krbPrincipal))
 447         goto cleanup;
 448
 449     match.client = cred->name->krbPrincipal;
 450     match.server = target->krbPrincipal;
 451     if (timeReq != 0 && timeReq != GSS_C_INDEFINITE)
 452         match.times.endtime = now + timeReq;
 453
 454     code = krb5_cc_default(krbContext, &ccache);
 455     if (code != 0)
 456         goto cleanup;
 457
 458     code = krb5_cc_retrieve_cred(krbContext, ccache, 0, &match, &creds);
 459     if (code != 0)
 460         goto cleanup;
 461
 462     cred->flags |= CRED_FLAG_DEFAULT_CCACHE;
 463     cred->krbCredCache = ccache;
 464     ccache = NULL;
 465
 466     major = gss_krb5_import_cred(minor, cred->krbCredCache, NULL, NULL,
 467                                  &cred->reauthCred);
 468
 469 cleanup:
 470     if (major == GSS_S_CRED_UNAVAIL)
 471         *minor = code;
 472
 473     if (ccache != NULL)
 474         krb5_cc_close(krbContext, ccache);
 475     krb5_free_cred_contents(krbContext, &creds);
 476
 477     return major;
 478 }
 479
 480 /*
 481  * Returns TRUE if the credential handle's reauth credentials are
 482  * valid or if we can use the default credentials cache. Credentials
 483  * handle must be locked.
 484  */
 485 int
 486 gssEapCanReauthP(gss_cred_id_t cred,
 487                  gss_name_t target,
 488                  OM_uint32 timeReq)
 489 {
 490     time_t now, expiryReq;
 491     OM_uint32 minor;
 492
 493     if (cred == GSS_C_NO_CREDENTIAL)
 494         return FALSE;
 495
 496     now = time(NULL);
 497     expiryReq = now;
 498     if (timeReq != GSS_C_INDEFINITE)
 499         expiryReq += timeReq;
 500
 501     if (cred->krbCredCache != NULL && cred->expiryTime > expiryReq)
 502         return TRUE;
 503
 504     if (getDefaultReauthCredentials(&minor, cred, target,
 505                                     now, timeReq) == GSS_S_COMPLETE)
 506         return TRUE;
 507
 508     return FALSE;
 509 }
 510
 511 /*
 512  * Store re-authentication (Kerberos) credentials in a credential handle.
 513  * Credentials handle must be locked.
 514  */
 515 OM_uint32
 516 gssEapStoreReauthCreds(OM_uint32 *minor,
 517                        gss_ctx_id_t ctx,
 518                        gss_cred_id_t cred,
 519                        gss_buffer_t credBuf)
 520 {
 521     OM_uint32 major = GSS_S_COMPLETE;
 522     krb5_error_code code;
 523     krb5_context krbContext = NULL;
 524     krb5_auth_context authContext = NULL;
 525     krb5_data credData = { 0 };
 526     krb5_creds **creds = NULL;
 527     krb5_principal canonPrinc;
 528     krb5_principal ccPrinc = NULL;
 529     int i;
 530
 531     if (credBuf->length == 0 || cred == GSS_C_NO_CREDENTIAL)
 532         return GSS_S_COMPLETE;
 533
 534     GSSEAP_KRB_INIT(&krbContext);
 535
 536     code = krb5_auth_con_init(krbContext, &authContext);
 537     if (code != 0)
 538         goto cleanup;
 539
 540     code = krb5_auth_con_setflags(krbContext, authContext, 0);
 541     if (code != 0)
 542         goto cleanup;
 543
 544     code = krb5_auth_con_setrecvsubkey(krbContext, authContext,
 545                                        &ctx->rfc3961Key);
 546     if (code != 0)
 547         goto cleanup;
 548
 549     gssBufferToKrbData(credBuf, &credData);
 550
 551     code = krb5_rd_cred(krbContext, authContext, &credData, &creds, NULL);
 552     if (code != 0)
 553         goto cleanup;
 554
 555     if (creds == NULL || creds[0] == NULL)
 556         goto cleanup;
 557
 558     code = krb5_copy_principal(krbContext, creds[0]->client, &canonPrinc);
 559     if (code != 0)
 560         goto cleanup;
 561
 562     krb5_free_principal(krbContext, cred->name->krbPrincipal);
 563     cred->name->krbPrincipal = canonPrinc;
 564
 565     if (creds[0]->times.endtime == KRB_TIME_FOREVER)
 566         cred->expiryTime = 0;
 567     else
 568         cred->expiryTime = creds[0]->times.endtime;
 569
 570     if (cred->krbCredCache == NULL) {
 571         if (reauthUseCredsCache(krbContext, creds[0]->client) &&
 572             krb5_cc_default(krbContext, &cred->krbCredCache) == 0)
 573             cred->flags |= CRED_FLAG_DEFAULT_CCACHE;
 574     } else {
 575         /*
 576          * If we already have an associated credentials cache, possibly from
 577          * the last time we stored a reauthentication credential, then we
 578          * need to clear it out and release the associated GSS credential.
 579          */
 580         if (cred->flags & CRED_FLAG_DEFAULT_CCACHE) {
 581             krb5_cc_remove_cred(krbContext, cred->krbCredCache, 0, creds[0]);
 582         } else {
 583             krb5_cc_destroy(krbContext, cred->krbCredCache);
 584             cred->krbCredCache = NULL;
 585         }
 586         gssReleaseCred(minor, &cred->reauthCred);
 587     }
 588
 589     if (cred->krbCredCache == NULL) {
 590         code = krb5_cc_new_unique(krbContext, "MEMORY", NULL, &cred->krbCredCache);
 591         if (code != 0)
 592             goto cleanup;
 593     }
 594
 595     if ((cred->flags & CRED_FLAG_DEFAULT_CCACHE) == 0 ||
 596         krb5_cc_get_principal(krbContext, cred->krbCredCache, &ccPrinc) != 0) {
 597         code = krb5_cc_initialize(krbContext, cred->krbCredCache,
 598                                   creds[0]->client);
 599         if (code != 0)
 600             goto cleanup;
 601     }
 602
 603     for (i = 0; creds[i] != NULL; i++) {
 604         krb5_creds kcred = *(creds[i]);
 605
 606         /*
 607          * Swap in the acceptor name the client asked for so
 608          * get_credentials() works. We're making the assumption that
 609          * any service tickets returned are for us. We'll need to
 610          * reflect some more on whether that is a safe assumption.
 611          */
 612         if (!isTicketGrantingServiceP(krbContext, kcred.server))
 613             kcred.server = ctx->acceptorName->krbPrincipal;
 614
 615         code = krb5_cc_store_cred(krbContext, cred->krbCredCache, &kcred);
 616         if (code != 0)
 617             goto cleanup;
 618     }
 619
 620     major = gss_krb5_import_cred(minor, cred->krbCredCache, NULL, NULL,
 621                                  &cred->reauthCred);
 622     if (GSS_ERROR(major))
 623         goto cleanup;
 624
 625 cleanup:
 626     *minor = code;
 627
 628     krb5_free_principal(krbContext, ccPrinc);
 629     krb5_auth_con_free(krbContext, authContext);
 630     if (creds != NULL) {
 631         for (i = 0; creds[i] != NULL; i++)
 632             krb5_free_creds(krbContext, creds[i]);
 633         GSSEAP_FREE(creds);
 634     }
 635     if (major == GSS_S_COMPLETE)
 636         major = *minor ? GSS_S_FAILURE : GSS_S_COMPLETE;
 637
 638     return major;
 639 }
 640
 641 #ifndef HAVE_HEIMDAL_VERSION
 642 static gss_buffer_desc radiusAvpKrbAttr = {
 643     sizeof("urn:authdata-aaa-radius") - 1, "urn:authdata-aaa-radius"
 644 };
 645 #endif
 646
 647 /*
 648  * Unfortunately extracting an AD-KDCIssued authorization data element
 649  * is pretty implementation-dependent. It's not possible to verify the
 650  * signature ourselves because the ticket session key is not exposed
 651  * outside GSS. In an ideal world, all AD-KDCIssued elements would be
 652  * verified by the Kerberos library and authentication would fail if
 653  * verification failed. We're not quite there yet and as a result have
 654  * to go through some hoops to get this to work. The alternative would
 655  * be to sign the authorization data with our long-term key, but it
 656  * seems a pity to compromise the design because of current implementation
 657  * limitations.
 658  *
 659  * (Specifically, the hoops involve a libkrb5 authorisation data plugin
 660  * that exposes the verified and serialised attribute context through
 661  * the Kerberos GSS mechanism's naming extensions API.)
 662  */
 663 static OM_uint32
 664 defrostAttrContext(OM_uint32 *minor,
 665 #ifdef HAVE_HEIMDAL_VERSION
 666                    gss_ctx_id_t glueContext,
 667 #else
 668                    gss_name_t glueName,
 669 #endif
 670                    gss_name_t mechName)
 671 {
 672     OM_uint32 major, tmpMinor;
 673 #ifdef HAVE_HEIMDAL_VERSION
 674     gss_OID_desc oid = { 0 };
 675     gss_buffer_set_t authData = GSS_C_NO_BUFFER_SET;
 676 #else
 677     gss_buffer_desc authData = GSS_C_EMPTY_BUFFER;
 678     gss_buffer_desc authDataDisplay = GSS_C_EMPTY_BUFFER;
 679     int more = -1;
 680     int authenticated, complete;
 681 #endif
 682
 683 #ifdef HAVE_HEIMDAL_VERSION
 684     major = composeOid(minor,
 685                        GSS_KRB5_EXTRACT_AUTHZ_DATA_FROM_SEC_CONTEXT_X->elements,
 686                        GSS_KRB5_EXTRACT_AUTHZ_DATA_FROM_SEC_CONTEXT_X->length,
 687                        KRB5_AUTHDATA_RADIUS_AVP, &oid);
 688     if (GSS_ERROR(major))
 689         return major;
 690
 691     /* XXX we are assuming that this verifies AD-KDCIssued signature */
 692     major = gssInquireSecContextByOid(minor, glueContext,
 693                                       &oid, &authData);
 694     if (major == GSS_S_COMPLETE) {
 695         if (authData == GSS_C_NO_BUFFER_SET || authData->count != 1)
 696             major = GSS_S_FAILURE;
 697         else
 698             major = gssEapImportAttrContext(minor, authData->elements, mechName);
 699     } else if (major == GSS_S_FAILURE && *minor == ENOENT) {
 700         /* This is the equivalent of GSS_S_UNAVAILABLE for MIT attr APIs */
 701         *minor = 0;
 702         major = GSS_S_COMPLETE;
 703     }
 704
 705     gss_release_buffer_set(&tmpMinor, &authData);
 706     GSSEAP_FREE(oid.elements);
 707 #else
 708     major = gssGetNameAttribute(minor, glueName, &radiusAvpKrbAttr,
 709                                 &authenticated, &complete,
 710                                 &authData, &authDataDisplay, &more);
 711     if (major == GSS_S_COMPLETE) {
 712         if (authenticated == 0)
 713             major = GSS_S_BAD_NAME;
 714         else
 715             major = gssEapImportAttrContext(minor, &authData, mechName);
 716     } else if (major == GSS_S_UNAVAILABLE) {
 717         major = GSS_S_COMPLETE;
 718     }
 719
 720     gss_release_buffer(&tmpMinor, &authData);
 721     gss_release_buffer(&tmpMinor, &authDataDisplay);
 722 #endif /* HAVE_HEIMDAL_VERSION */
 723
 724     return major;
 725 }
 726
 727 /*
 728  * Convert a mechanism glue to an EAP mechanism name by displaying and
 729  * importing it. This also handles the RADIUS attributes.
 730  */
 731 OM_uint32
 732 gssEapGlueToMechName(OM_uint32 *minor,
 733                      gss_ctx_id_t ctx,
 734                      gss_name_t glueName,
 735                      gss_name_t *pMechName)
 736 {
 737     OM_uint32 major, tmpMinor;
 738     gss_buffer_desc nameBuf = GSS_C_EMPTY_BUFFER;
 739
 740     *pMechName = GSS_C_NO_NAME;
 741
 742     major = gssDisplayName(minor, glueName, &nameBuf, NULL);
 743     if (GSS_ERROR(major))
 744         goto cleanup;
 745
 746     major = gssEapImportName(minor, &nameBuf, GSS_C_NT_USER_NAME,
 747                              ctx->mechanismUsed, pMechName);
 748     if (GSS_ERROR(major))
 749         goto cleanup;
 750
 751     major = defrostAttrContext(minor,
 752 #ifdef HAVE_HEIMDAL_VERSION
 753                                ctx->reauthCtx,
 754 #else
 755                                glueName,
 756 #endif
 757                                *pMechName);
 758     if (GSS_ERROR(major))
 759         goto cleanup;
 760
 761 cleanup:
 762     if (GSS_ERROR(major)) {
 763         gssReleaseName(&tmpMinor, pMechName);
 764         *pMechName = GSS_C_NO_NAME;
 765     }
 766
 767     gss_release_buffer(&tmpMinor, &nameBuf);
 768
 769     return major;
 770 }
 771
 772 /*
 773  * Convert an EAP mechanism name to a mechanism glue name by displaying
 774  * and importing it.
 775  */
 776 OM_uint32
 777 gssEapMechToGlueName(OM_uint32 *minor,
 778                      gss_name_t mechName,
 779                      gss_name_t *pGlueName)
 780 {
 781     OM_uint32 major, tmpMinor;
 782     gss_buffer_desc nameBuf = GSS_C_EMPTY_BUFFER;
 783
 784     *pGlueName = GSS_C_NO_NAME;
 785
 786     major = gssEapDisplayName(minor, mechName, &nameBuf, NULL);
 787     if (GSS_ERROR(major))
 788         goto cleanup;
 789
 790     major = gssImportName(minor, &nameBuf, GSS_C_NT_USER_NAME,
 791                           pGlueName);
 792     if (GSS_ERROR(major))
 793         goto cleanup;
 794
 795 cleanup:
 796     gss_release_buffer(&tmpMinor, &nameBuf);
 797
 798     return major;
 799 }
 800
 801 /*
 802  * Suck out the analgous elements of a Kerberos GSS context into an EAP
 803  * one so that the application doesn't know the difference.
 804  */
 805 OM_uint32
 806 gssEapReauthComplete(OM_uint32 *minor,
 807                      gss_ctx_id_t ctx,
 808                      gss_cred_id_t cred GSSEAP_UNUSED,
 809                      const gss_OID mech,
 810                      OM_uint32 timeRec)
 811 {
 812     OM_uint32 major, tmpMinor;
 813     gss_buffer_set_t keyData = GSS_C_NO_BUFFER_SET;
 814     krb5_context krbContext = NULL;
 815 #ifdef HAVE_HEIMDAL_VERSION
 816     krb5_storage *sp = NULL;
 817 #endif
 818
 819     GSSEAP_KRB_INIT(&krbContext);
 820
 821     if (!oidEqual(mech, gss_mech_krb5)) {
 822         major = GSS_S_BAD_MECH;
 823         goto cleanup;
 824     }
 825
 826     /* Get the raw subsession key and encryption type */
 827 #ifdef HAVE_HEIMDAL_VERSION
 828 #define KRB_GSS_SUBKEY_COUNT    1 /* encoded session key */
 829     major = gssInquireSecContextByOid(minor, ctx->reauthCtx,
 830                                       GSS_KRB5_GET_SUBKEY_X, &keyData);
 831 #else
 832 #define KRB_GSS_SUBKEY_COUNT    2 /* raw session key, enctype OID */
 833     major = gssInquireSecContextByOid(minor, ctx->reauthCtx,
 834                                       GSS_C_INQ_SSPI_SESSION_KEY, &keyData);
 835 #endif
 836     if (GSS_ERROR(major))
 837         goto cleanup;
 838
 839     if (keyData == GSS_C_NO_BUFFER_SET || keyData->count < KRB_GSS_SUBKEY_COUNT) {
 840         *minor = GSSEAP_KEY_UNAVAILABLE;
 841         major = GSS_S_FAILURE;
 842         goto cleanup;
 843     }
 844
 845 #ifdef HAVE_HEIMDAL_VERSION
 846     sp = krb5_storage_from_mem(keyData->elements[0].value,
 847                                keyData->elements[0].length);
 848     if (sp == NULL) {
 849         *minor = ENOMEM;
 850         major = GSS_S_FAILURE;
 851         goto cleanup;
 852     }
 853
 854     *minor = krb5_ret_keyblock(sp, &ctx->rfc3961Key);
 855     if (*minor != 0) {
 856         major = GSS_S_FAILURE;
 857         goto cleanup;
 858     }
 859 #else
 860     {
 861         gss_OID_desc oid;
 862         int suffix;
 863
 864         oid.length = keyData->elements[1].length;
 865         oid.elements = keyData->elements[1].value;
 866
 867         /* GSS_KRB5_SESSION_KEY_ENCTYPE_OID */
 868         major = decomposeOid(minor,
 869                              "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02\x04",
 870                              10, &oid, &suffix);
 871         if (GSS_ERROR(major))
 872             goto cleanup;
 873
 874         ctx->encryptionType = suffix;
 875     }
 876
 877     {
 878         krb5_keyblock key;
 879
 880         KRB_KEY_LENGTH(&key) = keyData->elements[0].length;
 881         KRB_KEY_DATA(&key)   = keyData->elements[0].value;
 882         KRB_KEY_TYPE(&key)   = ctx->encryptionType;
 883
 884         *minor = krb5_copy_keyblock_contents(krbContext,
 885                                              &key, &ctx->rfc3961Key);
 886         if (*minor != 0) {
 887             major = GSS_S_FAILURE;
 888             goto cleanup;
 889         }
 890     }
 891 #endif /* HAVE_HEIMDAL_VERSION */
 892
 893     major = rfc3961ChecksumTypeForKey(minor, &ctx->rfc3961Key,
 894                                       &ctx->checksumType);
 895     if (GSS_ERROR(major))
 896         goto cleanup;
 897
 898     if (timeRec != GSS_C_INDEFINITE)
 899         ctx->expiryTime = time(NULL) + timeRec;
 900
 901     /* Initialize our sequence state */
 902     major = sequenceInit(minor,
 903                          &ctx->seqState, ctx->recvSeq,
 904                          ((ctx->gssFlags & GSS_C_REPLAY_FLAG) != 0),
 905                          ((ctx->gssFlags & GSS_C_SEQUENCE_FLAG) != 0),
 906                          TRUE);
 907     if (GSS_ERROR(major))
 908         goto cleanup;
 909
 910     major = GSS_S_COMPLETE;
 911
 912 cleanup:
 913 #ifdef HAVE_HEIMDAL_VERSION
 914     if (sp != NULL)
 915         krb5_storage_free(sp);
 916 #endif
 917     gss_release_buffer_set(&tmpMinor, &keyData);
 918
 919     return major;
 920 }
 921
 922 /*
 923  * The remainder of this file consists of wrappers so we can call into the
 924  * mechanism glue without calling ourselves.
 925  */
 926 static OM_uint32
 927 (*gssInitSecContextNext)(OM_uint32 *,
 928                          gss_cred_id_t,
 929                          gss_ctx_id_t *,
 930                          gss_name_t,
 931                          gss_OID,
 932                          OM_uint32,
 933                          OM_uint32,
 934                          gss_channel_bindings_t,
 935                          gss_buffer_t,
 936                          gss_OID *,
 937                          gss_buffer_t,
 938                          OM_uint32 *,
 939                          OM_uint32 *);
 940
 941 static OM_uint32
 942 (*gssAcceptSecContextNext)(OM_uint32 *,
 943                            gss_ctx_id_t *,
 944                            gss_cred_id_t,
 945                            gss_buffer_t,
 946                            gss_channel_bindings_t,
 947                            gss_name_t *,
 948                            gss_OID *,
 949                            gss_buffer_t,
 950                            OM_uint32 *,
 951                            OM_uint32 *,
 952                            gss_cred_id_t *);
 953
 954 static OM_uint32
 955 (*gssReleaseCredNext)(OM_uint32 *, gss_cred_id_t *);
 956
 957 static OM_uint32
 958 (*gssReleaseNameNext)(OM_uint32 *, gss_name_t *);
 959
 960 static OM_uint32
 961 (*gssInquireSecContextByOidNext)(OM_uint32 *,
 962                                  const gss_ctx_id_t,
 963                                  const gss_OID,
 964                                  gss_buffer_set_t *);
 965
 966 static OM_uint32
 967 (*gssDeleteSecContextNext)(OM_uint32 *,
 968                           gss_ctx_id_t *,
 969                           gss_buffer_t);
 970
 971 static OM_uint32
 972 (*gssDisplayNameNext)(OM_uint32 *,
 973                       gss_name_t,
 974                       gss_buffer_t,
 975                       gss_OID *);
 976
 977 static OM_uint32
 978 (*gssImportNameNext)(OM_uint32 *,
 979                      gss_buffer_t,
 980                      gss_OID,
 981                      gss_name_t *);
 982
 983 static OM_uint32
 984 (*gssStoreCredNext)(OM_uint32 *,
 985                     const gss_cred_id_t,
 986                     gss_cred_usage_t,
 987                     const gss_OID,
 988                     OM_uint32,
 989                     OM_uint32,
 990                     gss_OID_set *,
 991                     gss_cred_usage_t *);
 992
 993 static OM_uint32
 994 (*gssGetNameAttributeNext)(OM_uint32 *,
 995                           gss_name_t,
 996                           gss_buffer_t,
 997                           int *,
 998                           int *,
 999                           gss_buffer_t,
1000                           gss_buffer_t,
1001                           int *);
1002
1003 #define NEXT_SYMBOL(local, global)  do {        \
1004         ((local) = dlsym(RTLD_NEXT, (global))); \
1005         if ((local) == NULL) {                  \
1006             *minor = GSSEAP_NO_MECHGLUE_SYMBOL; \
1007             major = GSS_S_UNAVAILABLE;          \
1008             /* but continue */                  \
1009         }                                       \
1010     } while (0)
1011
1012 OM_uint32
1013 gssEapReauthInitialize(OM_uint32 *minor)
1014 {
1015     OM_uint32 major = GSS_S_COMPLETE;
1016
1017     NEXT_SYMBOL(gssInitSecContextNext,         "gss_init_sec_context");
1018     NEXT_SYMBOL(gssAcceptSecContextNext,       "gss_accept_sec_context");
1019     NEXT_SYMBOL(gssReleaseCredNext,            "gss_release_cred");
1020     NEXT_SYMBOL(gssReleaseNameNext,            "gss_release_name");
1021     NEXT_SYMBOL(gssInquireSecContextByOidNext, "gss_inquire_sec_context_by_oid");
1022     NEXT_SYMBOL(gssDeleteSecContextNext,       "gss_delete_sec_context");
1023     NEXT_SYMBOL(gssDisplayNameNext,            "gss_display_name");
1024     NEXT_SYMBOL(gssImportNameNext,             "gss_import_name");
1025     NEXT_SYMBOL(gssStoreCredNext,              "gss_store_cred");
1026 #ifndef HAVE_HEIMDAL_VERSION
1027     NEXT_SYMBOL(gssGetNameAttributeNext,       "gss_get_name_attribute");
1028 #endif
1029
1030     return major;
1031 }
1032
1033 OM_uint32
1034 gssInitSecContext(OM_uint32 *minor,
1035                   gss_cred_id_t cred,
1036                   gss_ctx_id_t *context_handle,
1037                   gss_name_t target_name,
1038                   gss_OID mech_type,
1039                   OM_uint32 req_flags,
1040                   OM_uint32 time_req,
1041                   gss_channel_bindings_t input_chan_bindings,
1042                   gss_buffer_t input_token,
1043                   gss_OID *actual_mech_type,
1044                   gss_buffer_t output_token,
1045                   OM_uint32 *ret_flags,
1046                   OM_uint32 *time_rec)
1047 {
1048     if (gssInitSecContextNext == NULL) {
1049         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1050         return GSS_S_UNAVAILABLE;
1051     }
1052
1053     return gssInitSecContextNext(minor, cred, context_handle,
1054                                  target_name, mech_type, req_flags,
1055                                  time_req, input_chan_bindings,
1056                                  input_token, actual_mech_type,
1057                                  output_token, ret_flags, time_rec);
1058 }
1059
1060 OM_uint32
1061 gssAcceptSecContext(OM_uint32 *minor,
1062                     gss_ctx_id_t *context_handle,
1063                     gss_cred_id_t cred,
1064                     gss_buffer_t input_token,
1065                     gss_channel_bindings_t input_chan_bindings,
1066                     gss_name_t *src_name,
1067                     gss_OID *mech_type,
1068                     gss_buffer_t output_token,
1069                     OM_uint32 *ret_flags,
1070                     OM_uint32 *time_rec,
1071                     gss_cred_id_t *delegated_cred_handle)
1072 {
1073     if (gssAcceptSecContextNext == NULL) {
1074         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1075         return GSS_S_UNAVAILABLE;
1076     }
1077
1078     return gssAcceptSecContextNext(minor, context_handle, cred,
1079                                    input_token, input_chan_bindings,
1080                                    src_name, mech_type, output_token,
1081                                    ret_flags, time_rec, delegated_cred_handle);
1082 }
1083
1084 OM_uint32
1085 gssReleaseCred(OM_uint32 *minor,
1086                gss_cred_id_t *cred_handle)
1087 {
1088     if (gssReleaseCredNext == NULL) {
1089         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1090         return GSS_S_UNAVAILABLE;
1091     }
1092
1093     return gssReleaseCredNext(minor, cred_handle);
1094 }
1095
1096 OM_uint32
1097 gssReleaseName(OM_uint32 *minor,
1098                gss_name_t *name)
1099 {
1100     if (gssReleaseNameNext == NULL) {
1101         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1102         return GSS_S_UNAVAILABLE;
1103     }
1104
1105     return gssReleaseNameNext(minor, name);
1106 }
1107
1108 OM_uint32
1109 gssDeleteSecContext(OM_uint32 *minor,
1110                     gss_ctx_id_t *context_handle,
1111                     gss_buffer_t output_token)
1112 {
1113     if (gssDeleteSecContextNext == NULL) {
1114         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1115         return GSS_S_UNAVAILABLE;
1116     }
1117
1118     return gssDeleteSecContextNext(minor, context_handle, output_token);
1119 }
1120
1121 static OM_uint32
1122 gssDisplayName(OM_uint32 *minor,
1123                gss_name_t name,
1124                gss_buffer_t buffer,
1125                gss_OID *name_type)
1126 {
1127     if (gssDisplayNameNext == NULL) {
1128         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1129         return GSS_S_UNAVAILABLE;
1130     }
1131
1132     return gssDisplayNameNext(minor, name, buffer, name_type);
1133 }
1134
1135 static OM_uint32
1136 gssImportName(OM_uint32 *minor,
1137               gss_buffer_t buffer,
1138               gss_OID name_type,
1139               gss_name_t *name)
1140 {
1141     if (gssImportNameNext == NULL) {
1142         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1143         return GSS_S_UNAVAILABLE;
1144     }
1145
1146     return gssImportNameNext(minor, buffer, name_type, name);
1147 }
1148
1149 OM_uint32
1150 gssInquireSecContextByOid(OM_uint32 *minor,
1151                           const gss_ctx_id_t context_handle,
1152                           const gss_OID desired_object,
1153                           gss_buffer_set_t *data_set)
1154 {
1155     if (gssInquireSecContextByOidNext == NULL) {
1156         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1157         return GSS_S_UNAVAILABLE;
1158     }
1159
1160     return gssInquireSecContextByOidNext(minor, context_handle,
1161                                          desired_object, data_set);
1162 }
1163
1164 OM_uint32
1165 gssStoreCred(OM_uint32 *minor,
1166              const gss_cred_id_t input_cred_handle,
1167              gss_cred_usage_t input_usage,
1168              const gss_OID desired_mech,
1169              OM_uint32 overwrite_cred,
1170              OM_uint32 default_cred,
1171              gss_OID_set *elements_stored,
1172              gss_cred_usage_t *cred_usage_stored)
1173 {
1174     if (gssStoreCredNext == NULL) {
1175         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1176         return GSS_S_UNAVAILABLE;
1177     }
1178
1179     return gssStoreCredNext(minor, input_cred_handle, input_usage,
1180                             desired_mech, overwrite_cred, default_cred,
1181                             elements_stored, cred_usage_stored);
1182 }
1183
1184 OM_uint32
1185 gssGetNameAttribute(OM_uint32 *minor,
1186                     gss_name_t name,
1187                     gss_buffer_t attr,
1188                     int *authenticated,
1189                     int *complete,
1190                     gss_buffer_t value,
1191                     gss_buffer_t display_value,
1192                     int *more)
1193 {
1194     if (gssGetNameAttributeNext == NULL) {
1195         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1196         return GSS_S_UNAVAILABLE;
1197     }
1198
1199     return gssGetNameAttributeNext(minor, name, attr, authenticated, complete,
1200                                    value, display_value, more);
1201 }