www.project-moonshot.org Git - mech_eap.orig/blob - util_reauth.c

   1 /*
   2  * Copyright (c) 2010, JANET(UK)
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  *
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * 3. Neither the name of JANET(UK) nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  21  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 /*
  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 #ifdef HAVE_HEIMDAL_VERSION
  74     krb5_kt_cursor cursor = { 0 };
  75 #else
  76     krb5_kt_cursor cursor = NULL;
  77 #endif
  78
  79     *princ = NULL;
  80     memset(key, 0, sizeof(*key));
  81
  82     code = krb5_kt_default(krbContext, &keytab);
  83     if (code != 0)
  84         goto cleanup;
  85
  86     if (cred != GSS_C_NO_CREDENTIAL && cred->name != GSS_C_NO_NAME) {
  87         code = krb5_kt_get_entry(krbContext, keytab,
  88                                  cred->name->krbPrincipal, 0,
  89                                  ctx->encryptionType, &ktent);
  90         if (code != 0)
  91             goto cleanup;
  92     } else {
  93         /*
  94          * It's not clear that looking encrypting the ticket in the
  95          * requested EAP enctype provides any value.
  96          */
  97         code = krb5_kt_start_seq_get(krbContext, keytab, &cursor);
  98         if (code != 0)
  99             goto cleanup;
 100
 101         while ((code = krb5_kt_next_entry(krbContext, keytab,
 102                                           &ktent, &cursor)) == 0) {
 103 #ifdef HAVE_HEIMDAL_VERSION
 104             if (ktent.keyblock.keytype == ctx->encryptionType)
 105                 break;
 106             else
 107                 krb5_kt_free_entry(krbContext, &ktent);
 108 #else
 109             if (ktent.key.enctype == ctx->encryptionType)
 110                 break;
 111             else
 112                 krb5_free_keytab_entry_contents(krbContext, &ktent);
 113 #endif
 114         }
 115     }
 116
 117     if (code == 0) {
 118         *princ = ktent.principal;
 119 #ifdef HAVE_HEIMDAL_VERSION
 120         *key = ktent.keyblock;
 121 #else
 122         *key = ktent.key;
 123 #endif
 124     }
 125
 126 cleanup:
 127     if (cred == GSS_C_NO_CREDENTIAL || cred->name == GSS_C_NO_NAME)
 128         krb5_kt_end_seq_get(krbContext, keytab, &cursor);
 129     krb5_kt_close(krbContext, keytab);
 130
 131     if (code != 0)
 132 #ifdef HAVE_HEIMDAL_VERSION
 133         krb5_kt_free_entry(krbContext, &ktent);
 134 #else
 135         krb5_free_keytab_entry_contents(krbContext, &ktent);
 136 #endif
 137
 138     return code;
 139 }
 140
 141 static OM_uint32
 142 freezeAttrContext(OM_uint32 *minor,
 143                   gss_name_t initiatorName,
 144                   krb5_const_principal acceptorPrinc,
 145                   krb5_keyblock *session,
 146 #ifdef HAVE_HEIMDAL_VERSION
 147                   krb5_authdata *authdata
 148 #else
 149                   krb5_authdata ***authdata
 150 #endif
 151                   )
 152 {
 153     OM_uint32 major, tmpMinor;
 154     krb5_error_code code;
 155     gss_buffer_desc attrBuf = GSS_C_EMPTY_BUFFER;
 156 #ifdef HAVE_HEIMDAL_VERSION
 157     AuthorizationData authDataBuf, *authData = &authDataBuf;
 158     AuthorizationDataElement authDatum = { 0 };
 159 #else
 160     krb5_authdata *authData[2], authDatum = { 0 };
 161 #endif
 162     krb5_context krbContext;
 163
 164     GSSEAP_KRB_INIT(&krbContext);
 165
 166     major = gssEapExportAttrContext(minor, initiatorName, &attrBuf);
 167     if (GSS_ERROR(major))
 168         return major;
 169
 170     authDatum.ad_type = KRB5_AUTHDATA_RADIUS_AVP;
 171 #ifdef HAVE_HEIMDAL_VERSION
 172     authDatum.ad_data.length = attrBuf.length;
 173     authDatum.ad_data.data = attrBuf.value;
 174     authData->len = 1;
 175     authData->val = &authDatum;
 176 #else
 177     authDatum.length = attrBuf.length;
 178     authDatum.contents = attrBuf.value;
 179     authData[0] = &authDatum;
 180     authData[1] = NULL;
 181 #endif
 182
 183     code = krbMakeAuthDataKdcIssued(krbContext, session, acceptorPrinc,
 184                                     authData, authdata);
 185     if (code != 0) {
 186         major = GSS_S_FAILURE;
 187         *minor = code;
 188     } else {
 189         major = GSS_S_COMPLETE;
 190     }
 191
 192     gss_release_buffer(&tmpMinor, &attrBuf);
 193
 194     return major;
 195 }
 196
 197 /*
 198  * Fabricate a ticket to ourselves given a GSS EAP context.
 199  */
 200 OM_uint32
 201 gssEapMakeReauthCreds(OM_uint32 *minor,
 202                       gss_ctx_id_t ctx,
 203                       gss_cred_id_t cred,
 204                       gss_buffer_t credBuf)
 205 {
 206     OM_uint32 major = GSS_S_COMPLETE;
 207     krb5_error_code code;
 208     krb5_context krbContext = NULL;
 209     krb5_keyblock session = { 0 }, acceptorKey = { 0 };
 210     krb5_principal server = NULL;
 211 #ifdef HAVE_HEIMDAL_VERSION
 212     Ticket ticket;
 213     EncTicketPart enc_part;
 214     AuthorizationData authData = { 0 };
 215     krb5_crypto krbCrypto = NULL;
 216     unsigned char *buf = NULL;
 217     size_t buf_size, len;
 218 #else
 219     krb5_ticket ticket;
 220     krb5_enc_tkt_part enc_part;
 221 #endif
 222     krb5_data *ticketData = NULL, *credsData = NULL;
 223     krb5_creds creds = { 0 };
 224     krb5_auth_context authContext = NULL;
 225
 226     memset(&ticket, 0, sizeof(ticket));
 227     memset(&enc_part, 0, sizeof(enc_part));
 228
 229     credBuf->length = 0;
 230     credBuf->value = NULL;
 231
 232     GSSEAP_KRB_INIT(&krbContext);
 233
 234     code = getAcceptorKey(krbContext, ctx, cred, &server, &acceptorKey);
 235     if (code == KRB5_KT_NOTFOUND) {
 236         *minor = code;
 237         return GSS_S_UNAVAILABLE;
 238     } else if (code != 0)
 239         goto cleanup;
 240
 241 #ifdef HAVE_HEIMDAL_VERSION
 242     ticket.realm = server->realm;
 243     ticket.sname = server->name;
 244 #else
 245     ticket.server = server;
 246 #endif
 247
 248     /*
 249      * Generate a random session key to place in the ticket and
 250      * sign the "KDC-Issued" authorization data element.
 251      */
 252     code = krb5_c_make_random_key(krbContext, ctx->encryptionType,
 253                                   &session);
 254     if (code != 0)
 255         goto cleanup;
 256
 257 #ifdef HAVE_HEIMDAL_VERSION
 258     enc_part.flags.initial = 1;
 259     enc_part.key = session;
 260     enc_part.crealm = ctx->initiatorName->krbPrincipal->realm;
 261     enc_part.cname = ctx->initiatorName->krbPrincipal->name;
 262     enc_part.authtime = time(NULL);
 263     enc_part.starttime = &enc_part.authtime;
 264     enc_part.endtime = (ctx->expiryTime != 0)
 265                        ? ctx->expiryTime : KRB_TIME_FOREVER;
 266     enc_part.renew_till = NULL;
 267     enc_part.authorization_data = &authData;
 268
 269     major = freezeAttrContext(minor, ctx->initiatorName, server,
 270                               &session, &authData);
 271     if (GSS_ERROR(major))
 272         goto cleanup;
 273
 274     ASN1_MALLOC_ENCODE(EncTicketPart, buf, buf_size, &enc_part, &len, code);
 275     if (code != 0)
 276         goto cleanup;
 277
 278     code = krb5_crypto_init(krbContext, &acceptorKey, 0, &krbCrypto);
 279     if (code != 0)
 280         goto cleanup;
 281
 282     code = krb5_encrypt_EncryptedData(krbContext,
 283                                       krbCrypto,
 284                                       KRB5_KU_TICKET,
 285                                       buf,
 286                                       len,
 287                                       0,
 288                                       &ticket.enc_part);
 289     if (code != 0)
 290         goto cleanup;
 291
 292     GSSEAP_FREE(buf);
 293     buf = NULL;
 294
 295     ASN1_MALLOC_ENCODE(Ticket, buf, buf_size, &ticket, &len, code);
 296     if (code != 0)
 297         goto cleanup;
 298 #else
 299     enc_part.flags = TKT_FLG_INITIAL;
 300     enc_part.session = &session;
 301     enc_part.client = ctx->initiatorName->krbPrincipal;
 302     enc_part.times.authtime = time(NULL);
 303     enc_part.times.starttime = enc_part.times.authtime;
 304     enc_part.times.endtime = (ctx->expiryTime != 0)
 305                              ? ctx->expiryTime
 306                              : KRB_TIME_FOREVER;
 307     enc_part.times.renew_till = 0;
 308
 309     major = freezeAttrContext(minor, ctx->initiatorName, server,
 310                               &session, &enc_part.authorization_data);
 311     if (GSS_ERROR(major))
 312         goto cleanup;
 313
 314     ticket.enc_part2 = &enc_part;
 315
 316     code = krb5_encrypt_tkt_part(krbContext, &acceptorKey, &ticket);
 317     if (code != 0)
 318         goto cleanup;
 319
 320     code = encode_krb5_ticket(&ticket, &ticketData);
 321     if (code != 0)
 322         goto cleanup;
 323 #endif /* HAVE_HEIMDAL_VERSION */
 324
 325     creds.client = ctx->initiatorName->krbPrincipal;
 326     creds.server = server;
 327 #ifdef HAVE_HEIMDAL_VERSION
 328     creds.session = session;
 329     creds.times.authtime = enc_part.authtime;
 330     creds.times.starttime = *enc_part.starttime;
 331     creds.times.endtime = enc_part.endtime;
 332     creds.times.renew_till = 0;
 333     creds.flags.b = enc_part.flags;
 334     creds.ticket = *ticketData;
 335     creds.authdata = authData;
 336 #else
 337     creds.keyblock = session;
 338     creds.times = enc_part.times;
 339     creds.ticket_flags = enc_part.flags;
 340     creds.ticket = *ticketData;
 341     creds.authdata = enc_part.authorization_data;
 342 #endif
 343
 344     code = krb5_auth_con_init(krbContext, &authContext);
 345     if (code != 0)
 346         goto cleanup;
 347
 348     code = krb5_auth_con_setflags(krbContext, authContext, 0);
 349     if (code != 0)
 350         goto cleanup;
 351
 352     code = krb5_auth_con_setsendsubkey(krbContext, authContext,
 353                                        &ctx->rfc3961Key);
 354     if (code != 0)
 355         goto cleanup;
 356
 357     code = krb5_mk_1cred(krbContext, authContext, &creds, &credsData, NULL);
 358     if (code != 0)
 359         goto cleanup;
 360
 361     krbDataToGssBuffer(credsData, credBuf);
 362
 363 cleanup:
 364 #ifdef HAVE_HEIMDAL_VERSION
 365     if (krbCrypto != NULL)
 366         krb5_crypto_destroy(krbContext, krbCrypto);
 367     if (buf != NULL)
 368         GSSEAP_FREE(buf);
 369     free_AuthorizationData(&authData);
 370     free_EncryptedData(&ticket.enc_part);
 371 #else
 372     krb5_free_authdata(krbContext, enc_part.authorization_data);
 373     if (ticket.enc_part.ciphertext.data != NULL)
 374         GSSEAP_FREE(ticket.enc_part.ciphertext.data);
 375 #endif
 376     krb5_free_keyblock_contents(krbContext, &session);
 377     krb5_free_principal(krbContext, server);
 378     krb5_free_keyblock_contents(krbContext, &acceptorKey);
 379     krb5_free_data(krbContext, ticketData);
 380     krb5_auth_con_free(krbContext, authContext);
 381     if (credsData != NULL)
 382         GSSEAP_FREE(credsData);
 383
 384     if (major == GSS_S_COMPLETE) {
 385         *minor = code;
 386         major = (code != 0) ? GSS_S_FAILURE : GSS_S_COMPLETE;
 387     }
 388
 389     return major;
 390 }
 391
 392 static int
 393 isTicketGrantingServiceP(krb5_context krbContext,
 394                          krb5_const_principal principal)
 395 {
 396     if (KRB_PRINC_LENGTH(principal) == 2 &&
 397 #ifdef HAVE_HEIMDAL_VERSION
 398         strcmp(KRB_PRINC_NAME(principal)[0], "krbtgt") == 0
 399 #else
 400         krb5_princ_component(krbContext, principal, 0)->length == 6 &&
 401         memcmp(krb5_princ_component(krbContext,
 402                                     principal, 0)->data, "krbtgt", 6) == 0
 403 #endif
 404         )
 405         return TRUE;
 406
 407     return FALSE;
 408 }
 409
 410 /*
 411  * Returns TRUE if the configuration variable reauth_use_ccache is
 412  * set in krb5.conf for the eap_gss application and the client realm.
 413  */
 414 static int
 415 reauthUseCredsCache(krb5_context krbContext,
 416                     krb5_principal principal)
 417 {
 418     int reauthUseCCache;
 419
 420     /* if reauth_use_ccache, use default credentials cache if ticket is for us */
 421     krb5_appdefault_boolean(krbContext, "eap_gss",
 422                             KRB_PRINC_REALM(principal),
 423                             "reauth_use_ccache", 0, &reauthUseCCache);
 424
 425     return reauthUseCCache;
 426 }
 427
 428 /*
 429  * Look in default credentials cache for reauthentication credentials,
 430  * if policy allows.
 431  */
 432 static OM_uint32
 433 getDefaultReauthCredentials(OM_uint32 *minor,
 434                             gss_cred_id_t cred,
 435                             gss_name_t target,
 436                             time_t now,
 437                             OM_uint32 timeReq)
 438 {
 439     OM_uint32 major = GSS_S_CRED_UNAVAIL;
 440     krb5_context krbContext = NULL;
 441     krb5_error_code code = 0;
 442     krb5_ccache ccache = NULL;
 443     krb5_creds match = { 0 };
 444     krb5_creds creds = { 0 };
 445
 446     GSSEAP_KRB_INIT(&krbContext);
 447
 448     assert(cred != GSS_C_NO_CREDENTIAL);
 449     assert(target != GSS_C_NO_NAME);
 450
 451     if (cred->name == GSS_C_NO_NAME ||
 452         !reauthUseCredsCache(krbContext, cred->name->krbPrincipal))
 453         goto cleanup;
 454
 455     match.client = cred->name->krbPrincipal;
 456     match.server = target->krbPrincipal;
 457     if (timeReq != 0 && timeReq != GSS_C_INDEFINITE)
 458         match.times.endtime = now + timeReq;
 459
 460     code = krb5_cc_default(krbContext, &ccache);
 461     if (code != 0)
 462         goto cleanup;
 463
 464     code = krb5_cc_retrieve_cred(krbContext, ccache, 0, &match, &creds);
 465     if (code != 0)
 466         goto cleanup;
 467
 468     cred->flags |= CRED_FLAG_DEFAULT_CCACHE;
 469     cred->krbCredCache = ccache;
 470     ccache = NULL;
 471
 472     major = gss_krb5_import_cred(minor, cred->krbCredCache, NULL, NULL,
 473                                  &cred->krbCred);
 474
 475 cleanup:
 476     if (major == GSS_S_CRED_UNAVAIL)
 477         *minor = code;
 478
 479     if (ccache != NULL)
 480         krb5_cc_close(krbContext, ccache);
 481     krb5_free_cred_contents(krbContext, &creds);
 482
 483     return major;
 484 }
 485
 486 /*
 487  * Returns TRUE if the credential handle's reauth credentials are
 488  * valid or if we can use the default credentials cache. Credentials
 489  * handle must be locked.
 490  */
 491 int
 492 gssEapCanReauthP(gss_cred_id_t cred,
 493                  gss_name_t target,
 494                  OM_uint32 timeReq)
 495 {
 496     time_t now, expiryReq;
 497     OM_uint32 minor;
 498
 499     assert(cred != GSS_C_NO_CREDENTIAL);
 500
 501     now = time(NULL);
 502     expiryReq = now;
 503     if (timeReq != GSS_C_INDEFINITE)
 504         expiryReq += timeReq;
 505
 506     if (cred->krbCredCache != NULL && cred->expiryTime > expiryReq)
 507         return TRUE;
 508
 509     if (getDefaultReauthCredentials(&minor, cred, target,
 510                                     now, timeReq) == GSS_S_COMPLETE)
 511         return TRUE;
 512
 513     return FALSE;
 514 }
 515
 516 /*
 517  * Store re-authentication (Kerberos) credentials in a credential handle.
 518  * Credentials handle must be locked.
 519  */
 520 OM_uint32
 521 gssEapStoreReauthCreds(OM_uint32 *minor,
 522                        gss_ctx_id_t ctx,
 523                        gss_cred_id_t cred,
 524                        gss_buffer_t credBuf)
 525 {
 526     OM_uint32 major = GSS_S_COMPLETE;
 527     krb5_error_code code;
 528     krb5_context krbContext = NULL;
 529     krb5_auth_context authContext = NULL;
 530     krb5_data credData = { 0 };
 531     krb5_creds **creds = NULL;
 532     krb5_principal canonPrinc;
 533     krb5_principal ccPrinc = NULL;
 534     int i;
 535
 536     if (credBuf->length == 0 || cred == GSS_C_NO_CREDENTIAL)
 537         return GSS_S_COMPLETE;
 538
 539     GSSEAP_KRB_INIT(&krbContext);
 540
 541     code = krb5_auth_con_init(krbContext, &authContext);
 542     if (code != 0)
 543         goto cleanup;
 544
 545     code = krb5_auth_con_setflags(krbContext, authContext, 0);
 546     if (code != 0)
 547         goto cleanup;
 548
 549     code = krb5_auth_con_setrecvsubkey(krbContext, authContext,
 550                                        &ctx->rfc3961Key);
 551     if (code != 0)
 552         goto cleanup;
 553
 554     gssBufferToKrbData(credBuf, &credData);
 555
 556     code = krb5_rd_cred(krbContext, authContext, &credData, &creds, NULL);
 557     if (code != 0)
 558         goto cleanup;
 559
 560     if (creds == NULL || creds[0] == NULL)
 561         goto cleanup;
 562
 563     code = krb5_copy_principal(krbContext, creds[0]->client, &canonPrinc);
 564     if (code != 0)
 565         goto cleanup;
 566
 567     krb5_free_principal(krbContext, cred->name->krbPrincipal);
 568     cred->name->krbPrincipal = canonPrinc;
 569
 570     if (creds[0]->times.endtime == KRB_TIME_FOREVER)
 571         cred->expiryTime = 0;
 572     else
 573         cred->expiryTime = creds[0]->times.endtime;
 574
 575     if (cred->krbCredCache == NULL) {
 576         if (reauthUseCredsCache(krbContext, creds[0]->client) &&
 577             krb5_cc_default(krbContext, &cred->krbCredCache) == 0)
 578             cred->flags |= CRED_FLAG_DEFAULT_CCACHE;
 579     } else {
 580         /*
 581          * If we already have an associated credentials cache, possibly from
 582          * the last time we stored a reauthentication credential, then we
 583          * need to clear it out and release the associated GSS credential.
 584          */
 585         if (cred->flags & CRED_FLAG_DEFAULT_CCACHE) {
 586             krb5_cc_remove_cred(krbContext, cred->krbCredCache, 0, creds[0]);
 587         } else {
 588             krb5_cc_destroy(krbContext, cred->krbCredCache);
 589             cred->krbCredCache = NULL;
 590         }
 591         gssReleaseCred(minor, &cred->krbCred);
 592     }
 593
 594     if (cred->krbCredCache == NULL) {
 595         code = krb5_cc_new_unique(krbContext, "MEMORY", NULL, &cred->krbCredCache);
 596         if (code != 0)
 597             goto cleanup;
 598     }
 599
 600     if ((cred->flags & CRED_FLAG_DEFAULT_CCACHE) == 0 ||
 601         krb5_cc_get_principal(krbContext, cred->krbCredCache, &ccPrinc) != 0) {
 602         code = krb5_cc_initialize(krbContext, cred->krbCredCache,
 603                                   creds[0]->client);
 604         if (code != 0)
 605             goto cleanup;
 606     }
 607
 608     for (i = 0; creds[i] != NULL; i++) {
 609         krb5_creds kcred = *(creds[i]);
 610
 611         /*
 612          * Swap in the acceptor name the client asked for so
 613          * get_credentials() works. We're making the assumption that
 614          * any service tickets returned are for us. We'll need to
 615          * reflect some more on whether that is a safe assumption.
 616          */
 617         if (!isTicketGrantingServiceP(krbContext, kcred.server))
 618             kcred.server = ctx->acceptorName->krbPrincipal;
 619
 620         code = krb5_cc_store_cred(krbContext, cred->krbCredCache, &kcred);
 621         if (code != 0)
 622             goto cleanup;
 623     }
 624
 625     major = gss_krb5_import_cred(minor, cred->krbCredCache, NULL, NULL,
 626                                  &cred->krbCred);
 627     if (GSS_ERROR(major))
 628         goto cleanup;
 629
 630 cleanup:
 631     *minor = code;
 632
 633     krb5_free_principal(krbContext, ccPrinc);
 634     krb5_auth_con_free(krbContext, authContext);
 635     if (creds != NULL) {
 636         for (i = 0; creds[i] != NULL; i++)
 637             krb5_free_creds(krbContext, creds[i]);
 638         GSSEAP_FREE(creds);
 639     }
 640     if (major == GSS_S_COMPLETE)
 641         major = *minor ? GSS_S_FAILURE : GSS_S_COMPLETE;
 642
 643     return major;
 644 }
 645
 646 static gss_buffer_desc radiusAvpKrbAttr = {
 647     sizeof("urn:authdata-radius-avp") - 1, "urn:authdata-radius-avp"
 648 };
 649
 650 /*
 651  * Unfortunately extracting an AD-KDCIssued authorization data element
 652  * is pretty implementation-dependent. It's not possible to verify the
 653  * signature ourselves because the ticket session key is not exposed
 654  * outside GSS. In an ideal world, all AD-KDCIssued elements would be
 655  * verified by the Kerberos library and authentication would fail if
 656  * verification failed. We're not quite there yet and as a result have
 657  * to go through some hoops to get this to work. The alternative would
 658  * be to sign the authorization data with our long-term key, but it
 659  * seems a pity to compromise the design because of current implementation
 660  * limitations.
 661  *
 662  * (Specifically, the hoops involve a libkrb5 authorisation data plugin
 663  * that exposes the verified and serialised attribute context through
 664  * the Kerberos GSS mechanism's naming extensions API.)
 665  */
 666 static OM_uint32
 667 defrostAttrContext(OM_uint32 *minor,
 668                    gss_name_t glueName,
 669                    gss_name_t mechName)
 670 {
 671     OM_uint32 major, tmpMinor;
 672     gss_buffer_desc authData = GSS_C_EMPTY_BUFFER;
 673     gss_buffer_desc authDataDisplay = GSS_C_EMPTY_BUFFER;
 674     int more = -1;
 675     int authenticated, complete;
 676
 677     major = gssGetNameAttribute(minor, glueName, &radiusAvpKrbAttr,
 678                                 &authenticated, &complete,
 679                                 &authData, &authDataDisplay, &more);
 680     if (major == GSS_S_COMPLETE) {
 681         if (authenticated == 0)
 682             major = GSS_S_BAD_NAME;
 683         else
 684             major = gssEapImportAttrContext(minor, &authData, mechName);
 685     } else if (major == GSS_S_UNAVAILABLE) {
 686         major = GSS_S_COMPLETE;
 687     }
 688
 689     gss_release_buffer(&tmpMinor, &authData);
 690     gss_release_buffer(&tmpMinor, &authDataDisplay);
 691
 692     return major;
 693 }
 694
 695 /*
 696  * Convert a mechanism glue to an EAP mechanism name by displaying and
 697  * importing it. This also handles the RADIUS attributes.
 698  */
 699 OM_uint32
 700 gssEapGlueToMechName(OM_uint32 *minor,
 701                      gss_name_t glueName,
 702                      gss_name_t *pMechName)
 703 {
 704     OM_uint32 major, tmpMinor;
 705     gss_buffer_desc nameBuf = GSS_C_EMPTY_BUFFER;
 706
 707     *pMechName = GSS_C_NO_NAME;
 708
 709     major = gssDisplayName(minor, glueName, &nameBuf, NULL);
 710     if (GSS_ERROR(major))
 711         goto cleanup;
 712
 713     major = gssEapImportName(minor, &nameBuf, GSS_C_NT_USER_NAME,
 714                              pMechName);
 715     if (GSS_ERROR(major))
 716         goto cleanup;
 717
 718     major = defrostAttrContext(minor, glueName, *pMechName);
 719     if (GSS_ERROR(major))
 720         goto cleanup;
 721
 722 cleanup:
 723     if (GSS_ERROR(major)) {
 724         gssReleaseName(&tmpMinor, pMechName);
 725         *pMechName = GSS_C_NO_NAME;
 726     }
 727
 728     gss_release_buffer(&tmpMinor, &nameBuf);
 729
 730     return major;
 731 }
 732
 733 /*
 734  * Convert an EAP mechanism name to a mechanism glue name by displaying
 735  * and importing it.
 736  */
 737 OM_uint32
 738 gssEapMechToGlueName(OM_uint32 *minor,
 739                      gss_name_t mechName,
 740                      gss_name_t *pGlueName)
 741 {
 742     OM_uint32 major, tmpMinor;
 743     gss_buffer_desc nameBuf = GSS_C_EMPTY_BUFFER;
 744
 745     *pGlueName = GSS_C_NO_NAME;
 746
 747     major = gssEapDisplayName(minor, mechName, &nameBuf, NULL);
 748     if (GSS_ERROR(major))
 749         goto cleanup;
 750
 751     major = gssImportName(minor, &nameBuf, GSS_C_NT_USER_NAME,
 752                           pGlueName);
 753     if (GSS_ERROR(major))
 754         goto cleanup;
 755
 756 cleanup:
 757     gss_release_buffer(&tmpMinor, &nameBuf);
 758
 759     return major;
 760 }
 761
 762 /*
 763  * Suck out the analgous elements of a Kerberos GSS context into an EAP
 764  * one so that the application doesn't know the difference.
 765  */
 766 OM_uint32
 767 gssEapReauthComplete(OM_uint32 *minor,
 768                     gss_ctx_id_t ctx,
 769                     gss_cred_id_t cred,
 770                     const gss_OID mech,
 771                     OM_uint32 timeRec)
 772 {
 773     OM_uint32 major, tmpMinor;
 774     gss_buffer_set_t keyData = GSS_C_NO_BUFFER_SET;
 775     krb5_context krbContext = NULL;
 776 #ifdef HAVE_HEIMDAL_VERSION
 777     krb5_storage *sp = NULL;
 778 #endif
 779
 780     GSSEAP_KRB_INIT(&krbContext);
 781
 782     if (!oidEqual(mech, gss_mech_krb5)) {
 783         major = GSS_S_BAD_MECH;
 784         goto cleanup;
 785     }
 786
 787     /* Get the raw subsession key and encryption type */
 788 #ifdef HAVE_HEIMDAL_VERSION
 789 #define KRB_GSS_SUBKEY_COUNT    1 /* encoded session key */
 790     major = gssInquireSecContextByOid(minor, ctx->kerberosCtx,
 791                                       GSS_KRB5_GET_SUBKEY_X, &keyData);
 792 #else
 793 #define KRB_GSS_SUBKEY_COUNT    2 /* raw session key, enctype OID */
 794     major = gssInquireSecContextByOid(minor, ctx->kerberosCtx,
 795                                       GSS_C_INQ_SSPI_SESSION_KEY, &keyData);
 796 #endif
 797     if (GSS_ERROR(major))
 798         goto cleanup;
 799
 800     if (keyData == GSS_C_NO_BUFFER_SET || keyData->count < KRB_GSS_SUBKEY_COUNT) {
 801         *minor = GSSEAP_KEY_UNAVAILABLE;
 802         major = GSS_S_FAILURE;
 803         goto cleanup;
 804     }
 805
 806 #ifdef HAVE_HEIMDAL_VERSION
 807     sp = krb5_storage_from_mem(keyData->elements[0].value,
 808                                keyData->elements[0].length);
 809     if (sp == NULL) {
 810         *minor = ENOMEM;
 811         major = GSS_S_FAILURE;
 812         goto cleanup;
 813     }
 814
 815     *minor = krb5_ret_keyblock(sp, &ctx->rfc3961Key);
 816     if (*minor != 0) {
 817         major = GSS_S_FAILURE;
 818         goto cleanup;
 819     }
 820 #else
 821     {
 822         gss_OID_desc oid;
 823         int suffix;
 824
 825         oid.length = keyData->elements[1].length;
 826         oid.elements = keyData->elements[1].value;
 827
 828         /* GSS_KRB5_SESSION_KEY_ENCTYPE_OID */
 829         major = decomposeOid(minor,
 830                              "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02\x04",
 831                              10, &oid, &suffix);
 832         if (GSS_ERROR(major))
 833             goto cleanup;
 834
 835         ctx->encryptionType = suffix;
 836     }
 837
 838     {
 839         krb5_keyblock key;
 840
 841         KRB_KEY_LENGTH(&key) = keyData->elements[0].length;
 842         KRB_KEY_DATA(&key)   = keyData->elements[0].value;
 843         KRB_KEY_TYPE(&key)   = ctx->encryptionType;
 844
 845         *minor = krb5_copy_keyblock_contents(krbContext,
 846                                              &key, &ctx->rfc3961Key);
 847         if (*minor != 0) {
 848             major = GSS_S_FAILURE;
 849             goto cleanup;
 850         }
 851     }
 852 #endif /* HAVE_HEIMDAL_VERSION */
 853
 854     major = rfc3961ChecksumTypeForKey(minor, &ctx->rfc3961Key,
 855                                       &ctx->checksumType);
 856     if (GSS_ERROR(major))
 857         goto cleanup;
 858
 859     if (timeRec != GSS_C_INDEFINITE)
 860         ctx->expiryTime = time(NULL) + timeRec;
 861
 862     /* Initialize our sequence state */
 863     major = sequenceInit(minor,
 864                          &ctx->seqState, ctx->recvSeq,
 865                          ((ctx->gssFlags & GSS_C_REPLAY_FLAG) != 0),
 866                          ((ctx->gssFlags & GSS_C_SEQUENCE_FLAG) != 0),
 867                          TRUE);
 868     if (GSS_ERROR(major))
 869         goto cleanup;
 870
 871     major = GSS_S_COMPLETE;
 872
 873 cleanup:
 874 #ifdef HAVE_HEIMDAL_VERSION
 875     if (sp != NULL)
 876         krb5_storage_free(sp);
 877 #endif
 878     gss_release_buffer_set(&tmpMinor, &keyData);
 879
 880     return major;
 881 }
 882
 883 /*
 884  * The remainder of this file consists of wrappers so we can call into the
 885  * mechanism glue without calling ourselves.
 886  */
 887 static OM_uint32
 888 (*gssInitSecContextNext)(OM_uint32 *,
 889                          gss_cred_id_t,
 890                          gss_ctx_id_t *,
 891                          gss_name_t,
 892                          gss_OID,
 893                          OM_uint32,
 894                          OM_uint32,
 895                          gss_channel_bindings_t,
 896                          gss_buffer_t,
 897                          gss_OID *,
 898                          gss_buffer_t,
 899                          OM_uint32 *,
 900                          OM_uint32 *);
 901
 902 static OM_uint32
 903 (*gssAcceptSecContextNext)(OM_uint32 *,
 904                            gss_ctx_id_t *,
 905                            gss_cred_id_t,
 906                            gss_buffer_t,
 907                            gss_channel_bindings_t,
 908                            gss_name_t *,
 909                            gss_OID *,
 910                            gss_buffer_t,
 911                            OM_uint32 *,
 912                            OM_uint32 *,
 913                            gss_cred_id_t *);
 914
 915 static OM_uint32
 916 (*gssReleaseCredNext)(OM_uint32 *, gss_cred_id_t *);
 917
 918 static OM_uint32
 919 (*gssReleaseNameNext)(OM_uint32 *, gss_name_t *);
 920
 921 static OM_uint32
 922 (*gssInquireSecContextByOidNext)(OM_uint32 *,
 923                                  const gss_ctx_id_t,
 924                                  const gss_OID,
 925                                  gss_buffer_set_t *);
 926
 927 static OM_uint32
 928 (*gssDeleteSecContextNext)(OM_uint32 *,
 929                           gss_ctx_id_t *,
 930                           gss_buffer_t);
 931
 932 static OM_uint32
 933 (*gssDisplayNameNext)(OM_uint32 *,
 934                       gss_name_t,
 935                       gss_buffer_t,
 936                       gss_OID *);
 937
 938 static OM_uint32
 939 (*gssImportNameNext)(OM_uint32 *,
 940                      gss_buffer_t,
 941                      gss_OID,
 942                      gss_name_t *);
 943
 944 static OM_uint32
 945 (*gssStoreCredNext)(OM_uint32 *,
 946                     const gss_cred_id_t,
 947                     gss_cred_usage_t,
 948                     const gss_OID,
 949                     OM_uint32,
 950                     OM_uint32,
 951                     gss_OID_set *,
 952                     gss_cred_usage_t *);
 953
 954 static OM_uint32
 955 (*gssGetNameAttributeNext)(OM_uint32 *,
 956                           gss_name_t,
 957                           gss_buffer_t,
 958                           int *,
 959                           int *,
 960                           gss_buffer_t,
 961                           gss_buffer_t,
 962                           int *);
 963
 964 #define NEXT_SYMBOL(local, global)  do {        \
 965         ((local) = dlsym(RTLD_NEXT, (global))); \
 966         if ((local) == NULL) {                  \
 967             *minor = GSSEAP_NO_MECHGLUE_SYMBOL; \
 968             major = GSS_S_UNAVAILABLE;          \
 969             /* but continue */                  \
 970         }                                       \
 971     } while (0)
 972
 973 OM_uint32
 974 gssEapReauthInitialize(OM_uint32 *minor)
 975 {
 976     OM_uint32 major = GSS_S_COMPLETE;
 977
 978     NEXT_SYMBOL(gssInitSecContextNext,         "gss_init_sec_context");
 979     NEXT_SYMBOL(gssAcceptSecContextNext,       "gss_accept_sec_context");
 980     NEXT_SYMBOL(gssReleaseCredNext,            "gss_release_cred");
 981     NEXT_SYMBOL(gssReleaseNameNext,            "gss_release_name");
 982     NEXT_SYMBOL(gssInquireSecContextByOidNext, "gss_inquire_sec_context_by_oid");
 983     NEXT_SYMBOL(gssDeleteSecContextNext,       "gss_delete_sec_context");
 984     NEXT_SYMBOL(gssDisplayNameNext,            "gss_display_name");
 985     NEXT_SYMBOL(gssImportNameNext,             "gss_import_name");
 986     NEXT_SYMBOL(gssStoreCredNext,              "gss_store_cred");
 987     NEXT_SYMBOL(gssGetNameAttributeNext,       "gss_get_name_attribute");
 988
 989     return major;
 990 }
 991
 992 OM_uint32
 993 gssInitSecContext(OM_uint32 *minor,
 994                   gss_cred_id_t cred,
 995                   gss_ctx_id_t *context_handle,
 996                   gss_name_t target_name,
 997                   gss_OID mech_type,
 998                   OM_uint32 req_flags,
 999                   OM_uint32 time_req,
1000                   gss_channel_bindings_t input_chan_bindings,
1001                   gss_buffer_t input_token,
1002                   gss_OID *actual_mech_type,
1003                   gss_buffer_t output_token,
1004                   OM_uint32 *ret_flags,
1005                   OM_uint32 *time_rec)
1006 {
1007     if (gssInitSecContextNext == NULL) {
1008         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1009         return GSS_S_UNAVAILABLE;
1010     }
1011
1012     return gssInitSecContextNext(minor, cred, context_handle,
1013                                  target_name, mech_type, req_flags,
1014                                  time_req, input_chan_bindings,
1015                                  input_token, actual_mech_type,
1016                                  output_token, ret_flags, time_rec);
1017 }
1018
1019 OM_uint32
1020 gssAcceptSecContext(OM_uint32 *minor,
1021                     gss_ctx_id_t *context_handle,
1022                     gss_cred_id_t cred,
1023                     gss_buffer_t input_token,
1024                     gss_channel_bindings_t input_chan_bindings,
1025                     gss_name_t *src_name,
1026                     gss_OID *mech_type,
1027                     gss_buffer_t output_token,
1028                     OM_uint32 *ret_flags,
1029                     OM_uint32 *time_rec,
1030                     gss_cred_id_t *delegated_cred_handle)
1031 {
1032     if (gssAcceptSecContextNext == NULL) {
1033         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1034         return GSS_S_UNAVAILABLE;
1035     }
1036
1037     return gssAcceptSecContextNext(minor, context_handle, cred,
1038                                    input_token, input_chan_bindings,
1039                                    src_name, mech_type, output_token,
1040                                    ret_flags, time_rec, delegated_cred_handle);
1041 }
1042
1043 OM_uint32
1044 gssReleaseCred(OM_uint32 *minor,
1045                gss_cred_id_t *cred_handle)
1046 {
1047     if (gssReleaseCredNext == NULL) {
1048         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1049         return GSS_S_UNAVAILABLE;
1050     }
1051
1052     return gssReleaseCredNext(minor, cred_handle);
1053 }
1054
1055 OM_uint32
1056 gssReleaseName(OM_uint32 *minor,
1057                gss_name_t *name)
1058 {
1059     if (gssReleaseName == NULL) {
1060         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1061         return GSS_S_UNAVAILABLE;
1062     }
1063
1064     return gssReleaseNameNext(minor, name);
1065 }
1066
1067 OM_uint32
1068 gssDeleteSecContext(OM_uint32 *minor,
1069                     gss_ctx_id_t *context_handle,
1070                     gss_buffer_t output_token)
1071 {
1072     if (gssDeleteSecContextNext == NULL) {
1073         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1074         return GSS_S_UNAVAILABLE;
1075     }
1076
1077     return gssDeleteSecContextNext(minor, context_handle, output_token);
1078 }
1079
1080 static OM_uint32
1081 gssDisplayName(OM_uint32 *minor,
1082                gss_name_t name,
1083                gss_buffer_t buffer,
1084                gss_OID *name_type)
1085 {
1086     if (gssDisplayNameNext == NULL) {
1087         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1088         return GSS_S_UNAVAILABLE;
1089     }
1090
1091     return gssDisplayNameNext(minor, name, buffer, name_type);
1092 }
1093
1094 static OM_uint32
1095 gssImportName(OM_uint32 *minor,
1096               gss_buffer_t buffer,
1097               gss_OID name_type,
1098               gss_name_t *name)
1099 {
1100     if (gssImportNameNext == NULL) {
1101         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1102         return GSS_S_UNAVAILABLE;
1103     }
1104
1105     return gssImportNameNext(minor, buffer, name_type, name);
1106 }
1107
1108 OM_uint32
1109 gssInquireSecContextByOid(OM_uint32 *minor,
1110                           const gss_ctx_id_t context_handle,
1111                           const gss_OID desired_object,
1112                           gss_buffer_set_t *data_set)
1113 {
1114     if (gssInquireSecContextByOidNext == NULL) {
1115         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1116         return GSS_S_UNAVAILABLE;
1117     }
1118
1119     return gssInquireSecContextByOidNext(minor, context_handle,
1120                                          desired_object, data_set);
1121 }
1122
1123 OM_uint32
1124 gssStoreCred(OM_uint32 *minor,
1125              const gss_cred_id_t input_cred_handle,
1126              gss_cred_usage_t input_usage,
1127              const gss_OID desired_mech,
1128              OM_uint32 overwrite_cred,
1129              OM_uint32 default_cred,
1130              gss_OID_set *elements_stored,
1131              gss_cred_usage_t *cred_usage_stored)
1132 {
1133     if (gssStoreCredNext == NULL) {
1134         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1135         return GSS_S_UNAVAILABLE;
1136     }
1137
1138     return gssStoreCredNext(minor, input_cred_handle, input_usage,
1139                             desired_mech, overwrite_cred, default_cred,
1140                             elements_stored, cred_usage_stored);
1141 }
1142
1143 OM_uint32
1144 gssGetNameAttribute(OM_uint32 *minor,
1145                     gss_name_t name,
1146                     gss_buffer_t attr,
1147                     int *authenticated,
1148                     int *complete,
1149                     gss_buffer_t value,
1150                     gss_buffer_t display_value,
1151                     int *more)
1152 {
1153     if (gssGetNameAttributeNext == NULL) {
1154         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1155         return GSS_S_UNAVAILABLE;
1156     }
1157
1158     return gssGetNameAttributeNext(minor, name, attr, authenticated, complete,
1159                                    value, display_value, more);
1160 }