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