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     GSSEAP_KRB_INIT(&krbContext);
 218
 219     code = getAcceptorKey(krbContext, ctx, cred, &server, &acceptorKey);
 220     if (code == KRB5_KT_NOTFOUND) {
 221         *minor = code;
 222         return GSS_S_UNAVAILABLE;
 223     } else if (code != 0)
 224         goto cleanup;
 225
 226     /*
 227      * Generate a random session key to place in the ticket and
 228      * sign the "KDC-Issued" authorization data element.
 229      */
 230 #ifdef HAVE_HEIMDAL_VERSION
 231     ticket.realm = server->realm;
 232     ticket.sname = server->name;
 233
 234     code = krb5_generate_random_keyblock(krbContext, ctx->encryptionType,
 235                                          &session);
 236     if (code != 0)
 237         goto cleanup;
 238
 239     enc_part.flags.initial = 1;
 240     enc_part.key = session;
 241     enc_part.crealm = ctx->initiatorName->krbPrincipal->realm;
 242     enc_part.cname = ctx->initiatorName->krbPrincipal->name;
 243     enc_part.authtime = time(NULL);
 244     enc_part.starttime = &enc_part.authtime;
 245     enc_part.endtime = (ctx->expiryTime != 0)
 246                        ? ctx->expiryTime : KRB_TIME_FOREVER;
 247     enc_part.renew_till = NULL;
 248     enc_part.authorization_data = &authData;
 249
 250     major = freezeAttrContext(minor, ctx->initiatorName, server,
 251                               &session, &authData);
 252     if (GSS_ERROR(major))
 253         goto cleanup;
 254
 255     ASN1_MALLOC_ENCODE(EncTicketPart, encPartData.data, encPartData.length,
 256                        &enc_part, &len, code);
 257     if (code != 0)
 258         goto cleanup;
 259
 260     code = krb5_crypto_init(krbContext, &acceptorKey, 0, &krbCrypto);
 261     if (code != 0)
 262         goto cleanup;
 263
 264     code = krb5_encrypt_EncryptedData(krbContext,
 265                                       krbCrypto,
 266                                       KRB5_KU_TICKET,
 267                                       encPartData.data,
 268                                       encPartData.length,
 269                                       0,
 270                                       &ticket.enc_part);
 271     if (code != 0)
 272         goto cleanup;
 273
 274     ASN1_MALLOC_ENCODE(Ticket, ticketData.data, ticketData.length,
 275                        &ticket, &len, code);
 276     if (code != 0)
 277         goto cleanup;
 278 #else
 279     ticket.server = server;
 280
 281     code = krb5_c_make_random_key(krbContext, ctx->encryptionType,
 282                                   &session);
 283     if (code != 0)
 284         goto cleanup;
 285
 286     enc_part.flags = TKT_FLG_INITIAL;
 287     enc_part.session = &session;
 288     enc_part.client = ctx->initiatorName->krbPrincipal;
 289     enc_part.times.authtime = time(NULL);
 290     enc_part.times.starttime = enc_part.times.authtime;
 291     enc_part.times.endtime = (ctx->expiryTime != 0)
 292                              ? ctx->expiryTime
 293                              : KRB_TIME_FOREVER;
 294     enc_part.times.renew_till = 0;
 295
 296     major = freezeAttrContext(minor, ctx->initiatorName, server,
 297                               &session, &enc_part.authorization_data);
 298     if (GSS_ERROR(major))
 299         goto cleanup;
 300
 301     ticket.enc_part2 = &enc_part;
 302
 303     code = krb5_encrypt_tkt_part(krbContext, &acceptorKey, &ticket);
 304     if (code != 0)
 305         goto cleanup;
 306
 307     code = encode_krb5_ticket(&ticket, &ticketData);
 308     if (code != 0)
 309         goto cleanup;
 310 #endif /* HAVE_HEIMDAL_VERSION */
 311
 312     creds.client = ctx->initiatorName->krbPrincipal;
 313     creds.server = server;
 314 #ifdef HAVE_HEIMDAL_VERSION
 315     creds.session = session;
 316     creds.times.authtime = enc_part.authtime;
 317     creds.times.starttime = *enc_part.starttime;
 318     creds.times.endtime = enc_part.endtime;
 319     creds.times.renew_till = 0;
 320     creds.flags.b = enc_part.flags;
 321     creds.ticket = ticketData;
 322     creds.authdata = authData;
 323 #else
 324     creds.keyblock = session;
 325     creds.times = enc_part.times;
 326     creds.ticket_flags = enc_part.flags;
 327     creds.ticket = *ticketData;
 328     creds.authdata = enc_part.authorization_data;
 329 #endif
 330
 331     code = krb5_auth_con_init(krbContext, &authContext);
 332     if (code != 0)
 333         goto cleanup;
 334
 335     code = krb5_auth_con_setflags(krbContext, authContext, 0);
 336     if (code != 0)
 337         goto cleanup;
 338
 339     code = krb5_auth_con_setsendsubkey(krbContext, authContext,
 340                                        &ctx->rfc3961Key);
 341     if (code != 0)
 342         goto cleanup;
 343
 344     code = krbMakeCred(krbContext, authContext, &creds, &credsData);
 345     if (code != 0)
 346         goto cleanup;
 347
 348     krbDataToGssBuffer(&credsData, credBuf);
 349
 350 cleanup:
 351 #ifdef HAVE_HEIMDAL_VERSION
 352     if (krbCrypto != NULL)
 353         krb5_crypto_destroy(krbContext, krbCrypto);
 354     free_AuthorizationData(&authData);
 355     free_EncryptedData(&ticket.enc_part);
 356     krb5_data_free(&ticketData);
 357     krb5_data_free(&encPartData);
 358 #else
 359     krb5_free_authdata(krbContext, enc_part.authorization_data);
 360     if (ticket.enc_part.ciphertext.data != NULL)
 361         GSSEAP_FREE(ticket.enc_part.ciphertext.data);
 362     krb5_free_data(krbContext, ticketData);
 363 #endif
 364     krb5_free_keyblock_contents(krbContext, &session);
 365     krb5_free_principal(krbContext, server);
 366     krb5_free_keyblock_contents(krbContext, &acceptorKey);
 367     krb5_auth_con_free(krbContext, authContext);
 368
 369     if (major == GSS_S_COMPLETE) {
 370         *minor = code;
 371         major = (code != 0) ? GSS_S_FAILURE : GSS_S_COMPLETE;
 372     }
 373
 374     return major;
 375 }
 376
 377 static int
 378 isTicketGrantingServiceP(krb5_context krbContext GSSEAP_UNUSED,
 379                          krb5_const_principal principal)
 380 {
 381     if (KRB_PRINC_LENGTH(principal) == 2 &&
 382 #ifdef HAVE_HEIMDAL_VERSION
 383         strcmp(KRB_PRINC_NAME(principal)[0], "krbtgt") == 0
 384 #else
 385         krb5_princ_component(krbContext, principal, 0)->length == 6 &&
 386         memcmp(krb5_princ_component(krbContext,
 387                                     principal, 0)->data, "krbtgt", 6) == 0
 388 #endif
 389         )
 390         return TRUE;
 391
 392     return FALSE;
 393 }
 394
 395 /*
 396  * Returns TRUE if the configuration variable reauth_use_ccache is
 397  * set in krb5.conf for the eap_gss application and the client realm.
 398  */
 399 static int
 400 reauthUseCredsCache(krb5_context krbContext,
 401                     krb5_principal principal)
 402 {
 403     int reauthUseCCache;
 404
 405     /* if reauth_use_ccache, use default credentials cache if ticket is for us */
 406     krb5_appdefault_boolean(krbContext, "eap_gss",
 407                             KRB_PRINC_REALM(principal),
 408                             "reauth_use_ccache", 0, &reauthUseCCache);
 409
 410     return reauthUseCCache;
 411 }
 412
 413 /*
 414  * Look in default credentials cache for reauthentication credentials,
 415  * if policy allows.
 416  */
 417 static OM_uint32
 418 getDefaultReauthCredentials(OM_uint32 *minor,
 419                             gss_cred_id_t cred,
 420                             gss_name_t target,
 421                             time_t now,
 422                             OM_uint32 timeReq)
 423 {
 424     OM_uint32 major = GSS_S_CRED_UNAVAIL;
 425     krb5_context krbContext = NULL;
 426     krb5_error_code code = 0;
 427     krb5_ccache ccache = NULL;
 428     krb5_creds match = { 0 };
 429     krb5_creds creds = { 0 };
 430
 431     GSSEAP_KRB_INIT(&krbContext);
 432
 433     assert(cred != GSS_C_NO_CREDENTIAL);
 434     assert(target != GSS_C_NO_NAME);
 435
 436     if (cred->name == GSS_C_NO_NAME ||
 437         !reauthUseCredsCache(krbContext, cred->name->krbPrincipal))
 438         goto cleanup;
 439
 440     match.client = cred->name->krbPrincipal;
 441     match.server = target->krbPrincipal;
 442     if (timeReq != 0 && timeReq != GSS_C_INDEFINITE)
 443         match.times.endtime = now + timeReq;
 444
 445     code = krb5_cc_default(krbContext, &ccache);
 446     if (code != 0)
 447         goto cleanup;
 448
 449     code = krb5_cc_retrieve_cred(krbContext, ccache, 0, &match, &creds);
 450     if (code != 0)
 451         goto cleanup;
 452
 453     cred->flags |= CRED_FLAG_DEFAULT_CCACHE;
 454     cred->krbCredCache = ccache;
 455     ccache = NULL;
 456
 457     major = gss_krb5_import_cred(minor, cred->krbCredCache, NULL, NULL,
 458                                  &cred->krbCred);
 459
 460 cleanup:
 461     if (major == GSS_S_CRED_UNAVAIL)
 462         *minor = code;
 463
 464     if (ccache != NULL)
 465         krb5_cc_close(krbContext, ccache);
 466     krb5_free_cred_contents(krbContext, &creds);
 467
 468     return major;
 469 }
 470
 471 /*
 472  * Returns TRUE if the credential handle's reauth credentials are
 473  * valid or if we can use the default credentials cache. Credentials
 474  * handle must be locked.
 475  */
 476 int
 477 gssEapCanReauthP(gss_cred_id_t cred,
 478                  gss_name_t target,
 479                  OM_uint32 timeReq)
 480 {
 481     time_t now, expiryReq;
 482     OM_uint32 minor;
 483
 484     assert(cred != GSS_C_NO_CREDENTIAL);
 485
 486     now = time(NULL);
 487     expiryReq = now;
 488     if (timeReq != GSS_C_INDEFINITE)
 489         expiryReq += timeReq;
 490
 491     if (cred->krbCredCache != NULL && cred->expiryTime > expiryReq)
 492         return TRUE;
 493
 494     if (getDefaultReauthCredentials(&minor, cred, target,
 495                                     now, timeReq) == GSS_S_COMPLETE)
 496         return TRUE;
 497
 498     return FALSE;
 499 }
 500
 501 /*
 502  * Store re-authentication (Kerberos) credentials in a credential handle.
 503  * Credentials handle must be locked.
 504  */
 505 OM_uint32
 506 gssEapStoreReauthCreds(OM_uint32 *minor,
 507                        gss_ctx_id_t ctx,
 508                        gss_cred_id_t cred,
 509                        gss_buffer_t credBuf)
 510 {
 511     OM_uint32 major = GSS_S_COMPLETE;
 512     krb5_error_code code;
 513     krb5_context krbContext = NULL;
 514     krb5_auth_context authContext = NULL;
 515     krb5_data credData = { 0 };
 516     krb5_creds **creds = NULL;
 517     krb5_principal canonPrinc;
 518     krb5_principal ccPrinc = NULL;
 519     int i;
 520
 521     if (credBuf->length == 0 || cred == GSS_C_NO_CREDENTIAL)
 522         return GSS_S_COMPLETE;
 523
 524     GSSEAP_KRB_INIT(&krbContext);
 525
 526     code = krb5_auth_con_init(krbContext, &authContext);
 527     if (code != 0)
 528         goto cleanup;
 529
 530     code = krb5_auth_con_setflags(krbContext, authContext, 0);
 531     if (code != 0)
 532         goto cleanup;
 533
 534     code = krb5_auth_con_setrecvsubkey(krbContext, authContext,
 535                                        &ctx->rfc3961Key);
 536     if (code != 0)
 537         goto cleanup;
 538
 539     gssBufferToKrbData(credBuf, &credData);
 540
 541     code = krb5_rd_cred(krbContext, authContext, &credData, &creds, NULL);
 542     if (code != 0)
 543         goto cleanup;
 544
 545     if (creds == NULL || creds[0] == NULL)
 546         goto cleanup;
 547
 548     code = krb5_copy_principal(krbContext, creds[0]->client, &canonPrinc);
 549     if (code != 0)
 550         goto cleanup;
 551
 552     krb5_free_principal(krbContext, cred->name->krbPrincipal);
 553     cred->name->krbPrincipal = canonPrinc;
 554
 555     if (creds[0]->times.endtime == KRB_TIME_FOREVER)
 556         cred->expiryTime = 0;
 557     else
 558         cred->expiryTime = creds[0]->times.endtime;
 559
 560     if (cred->krbCredCache == NULL) {
 561         if (reauthUseCredsCache(krbContext, creds[0]->client) &&
 562             krb5_cc_default(krbContext, &cred->krbCredCache) == 0)
 563             cred->flags |= CRED_FLAG_DEFAULT_CCACHE;
 564     } else {
 565         /*
 566          * If we already have an associated credentials cache, possibly from
 567          * the last time we stored a reauthentication credential, then we
 568          * need to clear it out and release the associated GSS credential.
 569          */
 570         if (cred->flags & CRED_FLAG_DEFAULT_CCACHE) {
 571             krb5_cc_remove_cred(krbContext, cred->krbCredCache, 0, creds[0]);
 572         } else {
 573             krb5_cc_destroy(krbContext, cred->krbCredCache);
 574             cred->krbCredCache = NULL;
 575         }
 576         gssReleaseCred(minor, &cred->krbCred);
 577     }
 578
 579     if (cred->krbCredCache == NULL) {
 580         code = krb5_cc_new_unique(krbContext, "MEMORY", NULL, &cred->krbCredCache);
 581         if (code != 0)
 582             goto cleanup;
 583     }
 584
 585     if ((cred->flags & CRED_FLAG_DEFAULT_CCACHE) == 0 ||
 586         krb5_cc_get_principal(krbContext, cred->krbCredCache, &ccPrinc) != 0) {
 587         code = krb5_cc_initialize(krbContext, cred->krbCredCache,
 588                                   creds[0]->client);
 589         if (code != 0)
 590             goto cleanup;
 591     }
 592
 593     for (i = 0; creds[i] != NULL; i++) {
 594         krb5_creds kcred = *(creds[i]);
 595
 596         /*
 597          * Swap in the acceptor name the client asked for so
 598          * get_credentials() works. We're making the assumption that
 599          * any service tickets returned are for us. We'll need to
 600          * reflect some more on whether that is a safe assumption.
 601          */
 602         if (!isTicketGrantingServiceP(krbContext, kcred.server))
 603             kcred.server = ctx->acceptorName->krbPrincipal;
 604
 605         code = krb5_cc_store_cred(krbContext, cred->krbCredCache, &kcred);
 606         if (code != 0)
 607             goto cleanup;
 608     }
 609
 610     major = gss_krb5_import_cred(minor, cred->krbCredCache, NULL, NULL,
 611                                  &cred->krbCred);
 612     if (GSS_ERROR(major))
 613         goto cleanup;
 614
 615 cleanup:
 616     *minor = code;
 617
 618     krb5_free_principal(krbContext, ccPrinc);
 619     krb5_auth_con_free(krbContext, authContext);
 620     if (creds != NULL) {
 621         for (i = 0; creds[i] != NULL; i++)
 622             krb5_free_creds(krbContext, creds[i]);
 623         GSSEAP_FREE(creds);
 624     }
 625     if (major == GSS_S_COMPLETE)
 626         major = *minor ? GSS_S_FAILURE : GSS_S_COMPLETE;
 627
 628     return major;
 629 }
 630
 631 #ifndef HAVE_HEIMDAL_VERSION
 632 static gss_buffer_desc radiusAvpKrbAttr = {
 633     sizeof("urn:authdata-radius-avp") - 1, "urn:authdata-radius-avp"
 634 };
 635 #endif
 636
 637 /*
 638  * Unfortunately extracting an AD-KDCIssued authorization data element
 639  * is pretty implementation-dependent. It's not possible to verify the
 640  * signature ourselves because the ticket session key is not exposed
 641  * outside GSS. In an ideal world, all AD-KDCIssued elements would be
 642  * verified by the Kerberos library and authentication would fail if
 643  * verification failed. We're not quite there yet and as a result have
 644  * to go through some hoops to get this to work. The alternative would
 645  * be to sign the authorization data with our long-term key, but it
 646  * seems a pity to compromise the design because of current implementation
 647  * limitations.
 648  *
 649  * (Specifically, the hoops involve a libkrb5 authorisation data plugin
 650  * that exposes the verified and serialised attribute context through
 651  * the Kerberos GSS mechanism's naming extensions API.)
 652  */
 653 static OM_uint32
 654 defrostAttrContext(OM_uint32 *minor,
 655 #ifdef HAVE_HEIMDAL_VERSION
 656                    gss_ctx_id_t glueContext,
 657 #else
 658                    gss_ctx_id_t glueContext GSSEAP_UNUSED,
 659 #endif
 660                    gss_name_t glueName,
 661                    gss_name_t mechName)
 662 {
 663     OM_uint32 major, tmpMinor;
 664 #ifdef HAVE_HEIMDAL_VERSION
 665     gss_OID_desc oid = { 0 };
 666     gss_buffer_set_t authData = GSS_C_NO_BUFFER_SET;
 667 #else
 668     gss_buffer_desc authData = GSS_C_EMPTY_BUFFER;
 669     gss_buffer_desc authDataDisplay = GSS_C_EMPTY_BUFFER;
 670     int more = -1;
 671     int authenticated, complete;
 672 #endif
 673
 674 #ifdef HAVE_HEIMDAL_VERSION
 675     major = composeOid(minor,
 676                        GSS_KRB5_EXTRACT_AUTHZ_DATA_FROM_SEC_CONTEXT_X->elements,
 677                        GSS_KRB5_EXTRACT_AUTHZ_DATA_FROM_SEC_CONTEXT_X->length,
 678                        KRB5_AUTHDATA_RADIUS_AVP, &oid);
 679     if (GSS_ERROR(major))
 680         return major;
 681
 682     /* XXX we are assuming that this verifies AD-KDCIssued signature */
 683     major = gssInquireSecContextByOid(minor, glueContext,
 684                                       &oid, &authData);
 685     if (major == GSS_S_COMPLETE) {
 686         if (authData == GSS_C_NO_BUFFER_SET || authData->count != 1)
 687             major = GSS_S_FAILURE;
 688         else
 689             major = gssEapImportAttrContext(minor, authData->elements, mechName);
 690     } else if (major == GSS_S_FAILURE && *minor == ENOENT) {
 691         /* This is the equivalent of GSS_S_UNAVAILABLE for MIT attr APIs */
 692         *minor = 0;
 693         major = GSS_S_COMPLETE;
 694     }
 695
 696     gss_release_buffer_set(&tmpMinor, &authData);
 697     GSSEAP_FREE(oid.elements);
 698 #else
 699     major = gssGetNameAttribute(minor, glueName, &radiusAvpKrbAttr,
 700                                 &authenticated, &complete,
 701                                 &authData, &authDataDisplay, &more);
 702     if (major == GSS_S_COMPLETE) {
 703         if (authenticated == 0)
 704             major = GSS_S_BAD_NAME;
 705         else
 706             major = gssEapImportAttrContext(minor, &authData, mechName);
 707     } else if (major == GSS_S_UNAVAILABLE) {
 708         major = GSS_S_COMPLETE;
 709     }
 710
 711     gss_release_buffer(&tmpMinor, &authData);
 712     gss_release_buffer(&tmpMinor, &authDataDisplay);
 713 #endif /* HAVE_HEIMDAL_VERSION */
 714
 715     return major;
 716 }
 717
 718 /*
 719  * Convert a mechanism glue to an EAP mechanism name by displaying and
 720  * importing it. This also handles the RADIUS attributes.
 721  */
 722 OM_uint32
 723 gssEapGlueToMechName(OM_uint32 *minor,
 724                      gss_ctx_id_t glueContext,
 725                      gss_name_t glueName,
 726                      gss_name_t *pMechName)
 727 {
 728     OM_uint32 major, tmpMinor;
 729     gss_buffer_desc nameBuf = GSS_C_EMPTY_BUFFER;
 730
 731     *pMechName = GSS_C_NO_NAME;
 732
 733     major = gssDisplayName(minor, glueName, &nameBuf, NULL);
 734     if (GSS_ERROR(major))
 735         goto cleanup;
 736
 737     major = gssEapImportName(minor, &nameBuf, GSS_C_NT_USER_NAME,
 738                              pMechName);
 739     if (GSS_ERROR(major))
 740         goto cleanup;
 741
 742     major = defrostAttrContext(minor, glueContext, glueName, *pMechName);
 743     if (GSS_ERROR(major))
 744         goto cleanup;
 745
 746 cleanup:
 747     if (GSS_ERROR(major)) {
 748         gssReleaseName(&tmpMinor, pMechName);
 749         *pMechName = GSS_C_NO_NAME;
 750     }
 751
 752     gss_release_buffer(&tmpMinor, &nameBuf);
 753
 754     return major;
 755 }
 756
 757 /*
 758  * Convert an EAP mechanism name to a mechanism glue name by displaying
 759  * and importing it.
 760  */
 761 OM_uint32
 762 gssEapMechToGlueName(OM_uint32 *minor,
 763                      gss_name_t mechName,
 764                      gss_name_t *pGlueName)
 765 {
 766     OM_uint32 major, tmpMinor;
 767     gss_buffer_desc nameBuf = GSS_C_EMPTY_BUFFER;
 768
 769     *pGlueName = GSS_C_NO_NAME;
 770
 771     major = gssEapDisplayName(minor, mechName, &nameBuf, NULL);
 772     if (GSS_ERROR(major))
 773         goto cleanup;
 774
 775     major = gssImportName(minor, &nameBuf, GSS_C_NT_USER_NAME,
 776                           pGlueName);
 777     if (GSS_ERROR(major))
 778         goto cleanup;
 779
 780 cleanup:
 781     gss_release_buffer(&tmpMinor, &nameBuf);
 782
 783     return major;
 784 }
 785
 786 /*
 787  * Suck out the analgous elements of a Kerberos GSS context into an EAP
 788  * one so that the application doesn't know the difference.
 789  */
 790 OM_uint32
 791 gssEapReauthComplete(OM_uint32 *minor,
 792                      gss_ctx_id_t ctx,
 793                      gss_cred_id_t cred GSSEAP_UNUSED,
 794                      const gss_OID mech,
 795                      OM_uint32 timeRec)
 796 {
 797     OM_uint32 major, tmpMinor;
 798     gss_buffer_set_t keyData = GSS_C_NO_BUFFER_SET;
 799     krb5_context krbContext = NULL;
 800 #ifdef HAVE_HEIMDAL_VERSION
 801     krb5_storage *sp = NULL;
 802 #endif
 803
 804     GSSEAP_KRB_INIT(&krbContext);
 805
 806     if (!oidEqual(mech, gss_mech_krb5)) {
 807         major = GSS_S_BAD_MECH;
 808         goto cleanup;
 809     }
 810
 811     /* Get the raw subsession key and encryption type */
 812 #ifdef HAVE_HEIMDAL_VERSION
 813 #define KRB_GSS_SUBKEY_COUNT    1 /* encoded session key */
 814     major = gssInquireSecContextByOid(minor, ctx->kerberosCtx,
 815                                       GSS_KRB5_GET_SUBKEY_X, &keyData);
 816 #else
 817 #define KRB_GSS_SUBKEY_COUNT    2 /* raw session key, enctype OID */
 818     major = gssInquireSecContextByOid(minor, ctx->kerberosCtx,
 819                                       GSS_C_INQ_SSPI_SESSION_KEY, &keyData);
 820 #endif
 821     if (GSS_ERROR(major))
 822         goto cleanup;
 823
 824     if (keyData == GSS_C_NO_BUFFER_SET || keyData->count < KRB_GSS_SUBKEY_COUNT) {
 825         *minor = GSSEAP_KEY_UNAVAILABLE;
 826         major = GSS_S_FAILURE;
 827         goto cleanup;
 828     }
 829
 830 #ifdef HAVE_HEIMDAL_VERSION
 831     sp = krb5_storage_from_mem(keyData->elements[0].value,
 832                                keyData->elements[0].length);
 833     if (sp == NULL) {
 834         *minor = ENOMEM;
 835         major = GSS_S_FAILURE;
 836         goto cleanup;
 837     }
 838
 839     *minor = krb5_ret_keyblock(sp, &ctx->rfc3961Key);
 840     if (*minor != 0) {
 841         major = GSS_S_FAILURE;
 842         goto cleanup;
 843     }
 844 #else
 845     {
 846         gss_OID_desc oid;
 847         int suffix;
 848
 849         oid.length = keyData->elements[1].length;
 850         oid.elements = keyData->elements[1].value;
 851
 852         /* GSS_KRB5_SESSION_KEY_ENCTYPE_OID */
 853         major = decomposeOid(minor,
 854                              "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02\x04",
 855                              10, &oid, &suffix);
 856         if (GSS_ERROR(major))
 857             goto cleanup;
 858
 859         ctx->encryptionType = suffix;
 860     }
 861
 862     {
 863         krb5_keyblock key;
 864
 865         KRB_KEY_LENGTH(&key) = keyData->elements[0].length;
 866         KRB_KEY_DATA(&key)   = keyData->elements[0].value;
 867         KRB_KEY_TYPE(&key)   = ctx->encryptionType;
 868
 869         *minor = krb5_copy_keyblock_contents(krbContext,
 870                                              &key, &ctx->rfc3961Key);
 871         if (*minor != 0) {
 872             major = GSS_S_FAILURE;
 873             goto cleanup;
 874         }
 875     }
 876 #endif /* HAVE_HEIMDAL_VERSION */
 877
 878     major = rfc3961ChecksumTypeForKey(minor, &ctx->rfc3961Key,
 879                                       &ctx->checksumType);
 880     if (GSS_ERROR(major))
 881         goto cleanup;
 882
 883     if (timeRec != GSS_C_INDEFINITE)
 884         ctx->expiryTime = time(NULL) + timeRec;
 885
 886     /* Initialize our sequence state */
 887     major = sequenceInit(minor,
 888                          &ctx->seqState, ctx->recvSeq,
 889                          ((ctx->gssFlags & GSS_C_REPLAY_FLAG) != 0),
 890                          ((ctx->gssFlags & GSS_C_SEQUENCE_FLAG) != 0),
 891                          TRUE);
 892     if (GSS_ERROR(major))
 893         goto cleanup;
 894
 895     major = GSS_S_COMPLETE;
 896
 897 cleanup:
 898 #ifdef HAVE_HEIMDAL_VERSION
 899     if (sp != NULL)
 900         krb5_storage_free(sp);
 901 #endif
 902     gss_release_buffer_set(&tmpMinor, &keyData);
 903
 904     return major;
 905 }
 906
 907 /*
 908  * The remainder of this file consists of wrappers so we can call into the
 909  * mechanism glue without calling ourselves.
 910  */
 911 static OM_uint32
 912 (*gssInitSecContextNext)(OM_uint32 *,
 913                          gss_cred_id_t,
 914                          gss_ctx_id_t *,
 915                          gss_name_t,
 916                          gss_OID,
 917                          OM_uint32,
 918                          OM_uint32,
 919                          gss_channel_bindings_t,
 920                          gss_buffer_t,
 921                          gss_OID *,
 922                          gss_buffer_t,
 923                          OM_uint32 *,
 924                          OM_uint32 *);
 925
 926 static OM_uint32
 927 (*gssAcceptSecContextNext)(OM_uint32 *,
 928                            gss_ctx_id_t *,
 929                            gss_cred_id_t,
 930                            gss_buffer_t,
 931                            gss_channel_bindings_t,
 932                            gss_name_t *,
 933                            gss_OID *,
 934                            gss_buffer_t,
 935                            OM_uint32 *,
 936                            OM_uint32 *,
 937                            gss_cred_id_t *);
 938
 939 static OM_uint32
 940 (*gssReleaseCredNext)(OM_uint32 *, gss_cred_id_t *);
 941
 942 static OM_uint32
 943 (*gssReleaseNameNext)(OM_uint32 *, gss_name_t *);
 944
 945 static OM_uint32
 946 (*gssInquireSecContextByOidNext)(OM_uint32 *,
 947                                  const gss_ctx_id_t,
 948                                  const gss_OID,
 949                                  gss_buffer_set_t *);
 950
 951 static OM_uint32
 952 (*gssDeleteSecContextNext)(OM_uint32 *,
 953                           gss_ctx_id_t *,
 954                           gss_buffer_t);
 955
 956 static OM_uint32
 957 (*gssDisplayNameNext)(OM_uint32 *,
 958                       gss_name_t,
 959                       gss_buffer_t,
 960                       gss_OID *);
 961
 962 static OM_uint32
 963 (*gssImportNameNext)(OM_uint32 *,
 964                      gss_buffer_t,
 965                      gss_OID,
 966                      gss_name_t *);
 967
 968 static OM_uint32
 969 (*gssStoreCredNext)(OM_uint32 *,
 970                     const gss_cred_id_t,
 971                     gss_cred_usage_t,
 972                     const gss_OID,
 973                     OM_uint32,
 974                     OM_uint32,
 975                     gss_OID_set *,
 976                     gss_cred_usage_t *);
 977
 978 static OM_uint32
 979 (*gssGetNameAttributeNext)(OM_uint32 *,
 980                           gss_name_t,
 981                           gss_buffer_t,
 982                           int *,
 983                           int *,
 984                           gss_buffer_t,
 985                           gss_buffer_t,
 986                           int *);
 987
 988 #define NEXT_SYMBOL(local, global)  do {        \
 989         ((local) = dlsym(RTLD_NEXT, (global))); \
 990         if ((local) == NULL) {                  \
 991             *minor = GSSEAP_NO_MECHGLUE_SYMBOL; \
 992             major = GSS_S_UNAVAILABLE;          \
 993             /* but continue */                  \
 994         }                                       \
 995     } while (0)
 996
 997 OM_uint32
 998 gssEapReauthInitialize(OM_uint32 *minor)
 999 {
1000     OM_uint32 major = GSS_S_COMPLETE;
1001
1002     NEXT_SYMBOL(gssInitSecContextNext,         "gss_init_sec_context");
1003     NEXT_SYMBOL(gssAcceptSecContextNext,       "gss_accept_sec_context");
1004     NEXT_SYMBOL(gssReleaseCredNext,            "gss_release_cred");
1005     NEXT_SYMBOL(gssReleaseNameNext,            "gss_release_name");
1006     NEXT_SYMBOL(gssInquireSecContextByOidNext, "gss_inquire_sec_context_by_oid");
1007     NEXT_SYMBOL(gssDeleteSecContextNext,       "gss_delete_sec_context");
1008     NEXT_SYMBOL(gssDisplayNameNext,            "gss_display_name");
1009     NEXT_SYMBOL(gssImportNameNext,             "gss_import_name");
1010     NEXT_SYMBOL(gssStoreCredNext,              "gss_store_cred");
1011 #ifndef HAVE_HEIMDAL_VERSION
1012     NEXT_SYMBOL(gssGetNameAttributeNext,       "gss_get_name_attribute");
1013 #endif
1014
1015     return major;
1016 }
1017
1018 OM_uint32
1019 gssInitSecContext(OM_uint32 *minor,
1020                   gss_cred_id_t cred,
1021                   gss_ctx_id_t *context_handle,
1022                   gss_name_t target_name,
1023                   gss_OID mech_type,
1024                   OM_uint32 req_flags,
1025                   OM_uint32 time_req,
1026                   gss_channel_bindings_t input_chan_bindings,
1027                   gss_buffer_t input_token,
1028                   gss_OID *actual_mech_type,
1029                   gss_buffer_t output_token,
1030                   OM_uint32 *ret_flags,
1031                   OM_uint32 *time_rec)
1032 {
1033     if (gssInitSecContextNext == NULL) {
1034         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1035         return GSS_S_UNAVAILABLE;
1036     }
1037
1038     return gssInitSecContextNext(minor, cred, context_handle,
1039                                  target_name, mech_type, req_flags,
1040                                  time_req, input_chan_bindings,
1041                                  input_token, actual_mech_type,
1042                                  output_token, ret_flags, time_rec);
1043 }
1044
1045 OM_uint32
1046 gssAcceptSecContext(OM_uint32 *minor,
1047                     gss_ctx_id_t *context_handle,
1048                     gss_cred_id_t cred,
1049                     gss_buffer_t input_token,
1050                     gss_channel_bindings_t input_chan_bindings,
1051                     gss_name_t *src_name,
1052                     gss_OID *mech_type,
1053                     gss_buffer_t output_token,
1054                     OM_uint32 *ret_flags,
1055                     OM_uint32 *time_rec,
1056                     gss_cred_id_t *delegated_cred_handle)
1057 {
1058     if (gssAcceptSecContextNext == NULL) {
1059         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1060         return GSS_S_UNAVAILABLE;
1061     }
1062
1063     return gssAcceptSecContextNext(minor, context_handle, cred,
1064                                    input_token, input_chan_bindings,
1065                                    src_name, mech_type, output_token,
1066                                    ret_flags, time_rec, delegated_cred_handle);
1067 }
1068
1069 OM_uint32
1070 gssReleaseCred(OM_uint32 *minor,
1071                gss_cred_id_t *cred_handle)
1072 {
1073     if (gssReleaseCredNext == NULL) {
1074         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1075         return GSS_S_UNAVAILABLE;
1076     }
1077
1078     return gssReleaseCredNext(minor, cred_handle);
1079 }
1080
1081 OM_uint32
1082 gssReleaseName(OM_uint32 *minor,
1083                gss_name_t *name)
1084 {
1085     if (gssReleaseName == NULL) {
1086         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1087         return GSS_S_UNAVAILABLE;
1088     }
1089
1090     return gssReleaseNameNext(minor, name);
1091 }
1092
1093 OM_uint32
1094 gssDeleteSecContext(OM_uint32 *minor,
1095                     gss_ctx_id_t *context_handle,
1096                     gss_buffer_t output_token)
1097 {
1098     if (gssDeleteSecContextNext == NULL) {
1099         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1100         return GSS_S_UNAVAILABLE;
1101     }
1102
1103     return gssDeleteSecContextNext(minor, context_handle, output_token);
1104 }
1105
1106 static OM_uint32
1107 gssDisplayName(OM_uint32 *minor,
1108                gss_name_t name,
1109                gss_buffer_t buffer,
1110                gss_OID *name_type)
1111 {
1112     if (gssDisplayNameNext == NULL) {
1113         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1114         return GSS_S_UNAVAILABLE;
1115     }
1116
1117     return gssDisplayNameNext(minor, name, buffer, name_type);
1118 }
1119
1120 static OM_uint32
1121 gssImportName(OM_uint32 *minor,
1122               gss_buffer_t buffer,
1123               gss_OID name_type,
1124               gss_name_t *name)
1125 {
1126     if (gssImportNameNext == NULL) {
1127         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1128         return GSS_S_UNAVAILABLE;
1129     }
1130
1131     return gssImportNameNext(minor, buffer, name_type, name);
1132 }
1133
1134 OM_uint32
1135 gssInquireSecContextByOid(OM_uint32 *minor,
1136                           const gss_ctx_id_t context_handle,
1137                           const gss_OID desired_object,
1138                           gss_buffer_set_t *data_set)
1139 {
1140     if (gssInquireSecContextByOidNext == NULL) {
1141         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1142         return GSS_S_UNAVAILABLE;
1143     }
1144
1145     return gssInquireSecContextByOidNext(minor, context_handle,
1146                                          desired_object, data_set);
1147 }
1148
1149 OM_uint32
1150 gssStoreCred(OM_uint32 *minor,
1151              const gss_cred_id_t input_cred_handle,
1152              gss_cred_usage_t input_usage,
1153              const gss_OID desired_mech,
1154              OM_uint32 overwrite_cred,
1155              OM_uint32 default_cred,
1156              gss_OID_set *elements_stored,
1157              gss_cred_usage_t *cred_usage_stored)
1158 {
1159     if (gssStoreCredNext == NULL) {
1160         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1161         return GSS_S_UNAVAILABLE;
1162     }
1163
1164     return gssStoreCredNext(minor, input_cred_handle, input_usage,
1165                             desired_mech, overwrite_cred, default_cred,
1166                             elements_stored, cred_usage_stored);
1167 }
1168
1169 OM_uint32
1170 gssGetNameAttribute(OM_uint32 *minor,
1171                     gss_name_t name,
1172                     gss_buffer_t attr,
1173                     int *authenticated,
1174                     int *complete,
1175                     gss_buffer_t value,
1176                     gss_buffer_t display_value,
1177                     int *more)
1178 {
1179     if (gssGetNameAttributeNext == NULL) {
1180         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1181         return GSS_S_UNAVAILABLE;
1182     }
1183
1184     return gssGetNameAttributeNext(minor, name, attr, authenticated, complete,
1185                                    value, display_value, more);
1186 }