mech_eap/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     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     unsigned char *buf = NULL;
 200     size_t buf_size, len;
 201 #else
 202     krb5_ticket ticket;
 203     krb5_enc_tkt_part enc_part;
 204 #endif
 205     krb5_data *ticketData = NULL, credsData = { 0 };
 206     krb5_creds creds = { 0 };
 207     krb5_auth_context authContext = NULL;
 208
 209     memset(&ticket, 0, sizeof(ticket));
 210     memset(&enc_part, 0, sizeof(enc_part));
 211
 212     credBuf->length = 0;
 213     credBuf->value = NULL;
 214
 215     GSSEAP_KRB_INIT(&krbContext);
 216
 217     code = getAcceptorKey(krbContext, ctx, cred, &server, &acceptorKey);
 218     if (code == KRB5_KT_NOTFOUND) {
 219         *minor = code;
 220         return GSS_S_UNAVAILABLE;
 221     } else if (code != 0)
 222         goto cleanup;
 223
 224 #ifdef HAVE_HEIMDAL_VERSION
 225     ticket.realm = server->realm;
 226     ticket.sname = server->name;
 227 #else
 228     ticket.server = server;
 229 #endif
 230
 231     /*
 232      * Generate a random session key to place in the ticket and
 233      * sign the "KDC-Issued" authorization data element.
 234      */
 235     code = krb5_c_make_random_key(krbContext, ctx->encryptionType,
 236                                   &session);
 237     if (code != 0)
 238         goto cleanup;
 239
 240 #ifdef HAVE_HEIMDAL_VERSION
 241     enc_part.flags.initial = 1;
 242     enc_part.key = session;
 243     enc_part.crealm = ctx->initiatorName->krbPrincipal->realm;
 244     enc_part.cname = ctx->initiatorName->krbPrincipal->name;
 245     enc_part.authtime = time(NULL);
 246     enc_part.starttime = &enc_part.authtime;
 247     enc_part.endtime = (ctx->expiryTime != 0)
 248                        ? ctx->expiryTime : KRB_TIME_FOREVER;
 249     enc_part.renew_till = NULL;
 250     enc_part.authorization_data = &authData;
 251
 252     major = freezeAttrContext(minor, ctx->initiatorName, server,
 253                               &session, &authData);
 254     if (GSS_ERROR(major))
 255         goto cleanup;
 256
 257     ASN1_MALLOC_ENCODE(EncTicketPart, buf, buf_size, &enc_part, &len, code);
 258     if (code != 0)
 259         goto cleanup;
 260
 261     code = krb5_crypto_init(krbContext, &acceptorKey, 0, &krbCrypto);
 262     if (code != 0)
 263         goto cleanup;
 264
 265     code = krb5_encrypt_EncryptedData(krbContext,
 266                                       krbCrypto,
 267                                       KRB5_KU_TICKET,
 268                                       buf,
 269                                       len,
 270                                       0,
 271                                       &ticket.enc_part);
 272     if (code != 0)
 273         goto cleanup;
 274
 275     GSSEAP_FREE(buf);
 276     buf = NULL;
 277
 278     ASN1_MALLOC_ENCODE(Ticket, buf, buf_size, &ticket, &len, code);
 279     if (code != 0)
 280         goto cleanup;
 281 #else
 282     enc_part.flags = TKT_FLG_INITIAL;
 283     enc_part.session = &session;
 284     enc_part.client = ctx->initiatorName->krbPrincipal;
 285     enc_part.times.authtime = time(NULL);
 286     enc_part.times.starttime = enc_part.times.authtime;
 287     enc_part.times.endtime = (ctx->expiryTime != 0)
 288                              ? ctx->expiryTime
 289                              : KRB_TIME_FOREVER;
 290     enc_part.times.renew_till = 0;
 291
 292     major = freezeAttrContext(minor, ctx->initiatorName, server,
 293                               &session, &enc_part.authorization_data);
 294     if (GSS_ERROR(major))
 295         goto cleanup;
 296
 297     ticket.enc_part2 = &enc_part;
 298
 299     code = krb5_encrypt_tkt_part(krbContext, &acceptorKey, &ticket);
 300     if (code != 0)
 301         goto cleanup;
 302
 303     code = encode_krb5_ticket(&ticket, &ticketData);
 304     if (code != 0)
 305         goto cleanup;
 306 #endif /* HAVE_HEIMDAL_VERSION */
 307
 308     creds.client = ctx->initiatorName->krbPrincipal;
 309     creds.server = server;
 310 #ifdef HAVE_HEIMDAL_VERSION
 311     creds.session = session;
 312     creds.times.authtime = enc_part.authtime;
 313     creds.times.starttime = *enc_part.starttime;
 314     creds.times.endtime = enc_part.endtime;
 315     creds.times.renew_till = 0;
 316     creds.flags.b = enc_part.flags;
 317     creds.ticket = *ticketData;
 318     creds.authdata = authData;
 319 #else
 320     creds.keyblock = session;
 321     creds.times = enc_part.times;
 322     creds.ticket_flags = enc_part.flags;
 323     creds.ticket = *ticketData;
 324     creds.authdata = enc_part.authorization_data;
 325 #endif
 326
 327     code = krb5_auth_con_init(krbContext, &authContext);
 328     if (code != 0)
 329         goto cleanup;
 330
 331     code = krb5_auth_con_setflags(krbContext, authContext, 0);
 332     if (code != 0)
 333         goto cleanup;
 334
 335     code = krb5_auth_con_setsendsubkey(krbContext, authContext,
 336                                        &ctx->rfc3961Key);
 337     if (code != 0)
 338         goto cleanup;
 339
 340     code = krbMakeCred(krbContext, authContext, &creds, &credsData);
 341     if (code != 0)
 342         goto cleanup;
 343
 344     krbDataToGssBuffer(&credsData, credBuf);
 345
 346 cleanup:
 347 #ifdef HAVE_HEIMDAL_VERSION
 348     if (krbCrypto != NULL)
 349         krb5_crypto_destroy(krbContext, krbCrypto);
 350     if (buf != NULL)
 351         GSSEAP_FREE(buf);
 352     free_AuthorizationData(&authData);
 353     free_EncryptedData(&ticket.enc_part);
 354 #else
 355     krb5_free_authdata(krbContext, enc_part.authorization_data);
 356     if (ticket.enc_part.ciphertext.data != NULL)
 357         GSSEAP_FREE(ticket.enc_part.ciphertext.data);
 358 #endif
 359     krb5_free_keyblock_contents(krbContext, &session);
 360     krb5_free_principal(krbContext, server);
 361     krb5_free_keyblock_contents(krbContext, &acceptorKey);
 362     krb5_free_data(krbContext, ticketData);
 363     krb5_auth_con_free(krbContext, authContext);
 364
 365     if (major == GSS_S_COMPLETE) {
 366         *minor = code;
 367         major = (code != 0) ? GSS_S_FAILURE : GSS_S_COMPLETE;
 368     }
 369
 370     return major;
 371 }
 372
 373 static int
 374 isTicketGrantingServiceP(krb5_context krbContext,
 375                          krb5_const_principal principal)
 376 {
 377     if (KRB_PRINC_LENGTH(principal) == 2 &&
 378 #ifdef HAVE_HEIMDAL_VERSION
 379         strcmp(KRB_PRINC_NAME(principal)[0], "krbtgt") == 0
 380 #else
 381         krb5_princ_component(krbContext, principal, 0)->length == 6 &&
 382         memcmp(krb5_princ_component(krbContext,
 383                                     principal, 0)->data, "krbtgt", 6) == 0
 384 #endif
 385         )
 386         return TRUE;
 387
 388     return FALSE;
 389 }
 390
 391 /*
 392  * Returns TRUE if the configuration variable reauth_use_ccache is
 393  * set in krb5.conf for the eap_gss application and the client realm.
 394  */
 395 static int
 396 reauthUseCredsCache(krb5_context krbContext,
 397                     krb5_principal principal)
 398 {
 399     int reauthUseCCache;
 400
 401     /* if reauth_use_ccache, use default credentials cache if ticket is for us */
 402     krb5_appdefault_boolean(krbContext, "eap_gss",
 403                             KRB_PRINC_REALM(principal),
 404                             "reauth_use_ccache", 0, &reauthUseCCache);
 405
 406     return reauthUseCCache;
 407 }
 408
 409 /*
 410  * Look in default credentials cache for reauthentication credentials,
 411  * if policy allows.
 412  */
 413 static OM_uint32
 414 getDefaultReauthCredentials(OM_uint32 *minor,
 415                             gss_cred_id_t cred,
 416                             gss_name_t target,
 417                             time_t now,
 418                             OM_uint32 timeReq)
 419 {
 420     OM_uint32 major = GSS_S_CRED_UNAVAIL;
 421     krb5_context krbContext = NULL;
 422     krb5_error_code code = 0;
 423     krb5_ccache ccache = NULL;
 424     krb5_creds match = { 0 };
 425     krb5_creds creds = { 0 };
 426
 427     GSSEAP_KRB_INIT(&krbContext);
 428
 429     assert(cred != GSS_C_NO_CREDENTIAL);
 430     assert(target != GSS_C_NO_NAME);
 431
 432     if (cred->name == GSS_C_NO_NAME ||
 433         !reauthUseCredsCache(krbContext, cred->name->krbPrincipal))
 434         goto cleanup;
 435
 436     match.client = cred->name->krbPrincipal;
 437     match.server = target->krbPrincipal;
 438     if (timeReq != 0 && timeReq != GSS_C_INDEFINITE)
 439         match.times.endtime = now + timeReq;
 440
 441     code = krb5_cc_default(krbContext, &ccache);
 442     if (code != 0)
 443         goto cleanup;
 444
 445     code = krb5_cc_retrieve_cred(krbContext, ccache, 0, &match, &creds);
 446     if (code != 0)
 447         goto cleanup;
 448
 449     cred->flags |= CRED_FLAG_DEFAULT_CCACHE;
 450     cred->krbCredCache = ccache;
 451     ccache = NULL;
 452
 453     major = gss_krb5_import_cred(minor, cred->krbCredCache, NULL, NULL,
 454                                  &cred->krbCred);
 455
 456 cleanup:
 457     if (major == GSS_S_CRED_UNAVAIL)
 458         *minor = code;
 459
 460     if (ccache != NULL)
 461         krb5_cc_close(krbContext, ccache);
 462     krb5_free_cred_contents(krbContext, &creds);
 463
 464     return major;
 465 }
 466
 467 /*
 468  * Returns TRUE if the credential handle's reauth credentials are
 469  * valid or if we can use the default credentials cache. Credentials
 470  * handle must be locked.
 471  */
 472 int
 473 gssEapCanReauthP(gss_cred_id_t cred,
 474                  gss_name_t target,
 475                  OM_uint32 timeReq)
 476 {
 477     time_t now, expiryReq;
 478     OM_uint32 minor;
 479
 480     assert(cred != GSS_C_NO_CREDENTIAL);
 481
 482     now = time(NULL);
 483     expiryReq = now;
 484     if (timeReq != GSS_C_INDEFINITE)
 485         expiryReq += timeReq;
 486
 487     if (cred->krbCredCache != NULL && cred->expiryTime > expiryReq)
 488         return TRUE;
 489
 490     if (getDefaultReauthCredentials(&minor, cred, target,
 491                                     now, timeReq) == GSS_S_COMPLETE)
 492         return TRUE;
 493
 494     return FALSE;
 495 }
 496
 497 /*
 498  * Store re-authentication (Kerberos) credentials in a credential handle.
 499  * Credentials handle must be locked.
 500  */
 501 OM_uint32
 502 gssEapStoreReauthCreds(OM_uint32 *minor,
 503                        gss_ctx_id_t ctx,
 504                        gss_cred_id_t cred,
 505                        gss_buffer_t credBuf)
 506 {
 507     OM_uint32 major = GSS_S_COMPLETE;
 508     krb5_error_code code;
 509     krb5_context krbContext = NULL;
 510     krb5_auth_context authContext = NULL;
 511     krb5_data credData = { 0 };
 512     krb5_creds **creds = NULL;
 513     krb5_principal canonPrinc;
 514     krb5_principal ccPrinc = NULL;
 515     int i;
 516
 517     if (credBuf->length == 0 || cred == GSS_C_NO_CREDENTIAL)
 518         return GSS_S_COMPLETE;
 519
 520     GSSEAP_KRB_INIT(&krbContext);
 521
 522     code = krb5_auth_con_init(krbContext, &authContext);
 523     if (code != 0)
 524         goto cleanup;
 525
 526     code = krb5_auth_con_setflags(krbContext, authContext, 0);
 527     if (code != 0)
 528         goto cleanup;
 529
 530     code = krb5_auth_con_setrecvsubkey(krbContext, authContext,
 531                                        &ctx->rfc3961Key);
 532     if (code != 0)
 533         goto cleanup;
 534
 535     gssBufferToKrbData(credBuf, &credData);
 536
 537     code = krb5_rd_cred(krbContext, authContext, &credData, &creds, NULL);
 538     if (code != 0)
 539         goto cleanup;
 540
 541     if (creds == NULL || creds[0] == NULL)
 542         goto cleanup;
 543
 544     code = krb5_copy_principal(krbContext, creds[0]->client, &canonPrinc);
 545     if (code != 0)
 546         goto cleanup;
 547
 548     krb5_free_principal(krbContext, cred->name->krbPrincipal);
 549     cred->name->krbPrincipal = canonPrinc;
 550
 551     if (creds[0]->times.endtime == KRB_TIME_FOREVER)
 552         cred->expiryTime = 0;
 553     else
 554         cred->expiryTime = creds[0]->times.endtime;
 555
 556     if (cred->krbCredCache == NULL) {
 557         if (reauthUseCredsCache(krbContext, creds[0]->client) &&
 558             krb5_cc_default(krbContext, &cred->krbCredCache) == 0)
 559             cred->flags |= CRED_FLAG_DEFAULT_CCACHE;
 560     } else {
 561         /*
 562          * If we already have an associated credentials cache, possibly from
 563          * the last time we stored a reauthentication credential, then we
 564          * need to clear it out and release the associated GSS credential.
 565          */
 566         if (cred->flags & CRED_FLAG_DEFAULT_CCACHE) {
 567             krb5_cc_remove_cred(krbContext, cred->krbCredCache, 0, creds[0]);
 568         } else {
 569             krb5_cc_destroy(krbContext, cred->krbCredCache);
 570             cred->krbCredCache = NULL;
 571         }
 572         gssReleaseCred(minor, &cred->krbCred);
 573     }
 574
 575     if (cred->krbCredCache == NULL) {
 576         code = krb5_cc_new_unique(krbContext, "MEMORY", NULL, &cred->krbCredCache);
 577         if (code != 0)
 578             goto cleanup;
 579     }
 580
 581     if ((cred->flags & CRED_FLAG_DEFAULT_CCACHE) == 0 ||
 582         krb5_cc_get_principal(krbContext, cred->krbCredCache, &ccPrinc) != 0) {
 583         code = krb5_cc_initialize(krbContext, cred->krbCredCache,
 584                                   creds[0]->client);
 585         if (code != 0)
 586             goto cleanup;
 587     }
 588
 589     for (i = 0; creds[i] != NULL; i++) {
 590         krb5_creds kcred = *(creds[i]);
 591
 592         /*
 593          * Swap in the acceptor name the client asked for so
 594          * get_credentials() works. We're making the assumption that
 595          * any service tickets returned are for us. We'll need to
 596          * reflect some more on whether that is a safe assumption.
 597          */
 598         if (!isTicketGrantingServiceP(krbContext, kcred.server))
 599             kcred.server = ctx->acceptorName->krbPrincipal;
 600
 601         code = krb5_cc_store_cred(krbContext, cred->krbCredCache, &kcred);
 602         if (code != 0)
 603             goto cleanup;
 604     }
 605
 606     major = gss_krb5_import_cred(minor, cred->krbCredCache, NULL, NULL,
 607                                  &cred->krbCred);
 608     if (GSS_ERROR(major))
 609         goto cleanup;
 610
 611 cleanup:
 612     *minor = code;
 613
 614     krb5_free_principal(krbContext, ccPrinc);
 615     krb5_auth_con_free(krbContext, authContext);
 616     if (creds != NULL) {
 617         for (i = 0; creds[i] != NULL; i++)
 618             krb5_free_creds(krbContext, creds[i]);
 619         GSSEAP_FREE(creds);
 620     }
 621     if (major == GSS_S_COMPLETE)
 622         major = *minor ? GSS_S_FAILURE : GSS_S_COMPLETE;
 623
 624     return major;
 625 }
 626
 627 #ifndef HAVE_HEIMDAL_VERSION
 628 static gss_buffer_desc radiusAvpKrbAttr = {
 629     sizeof("urn:authdata-radius-avp") - 1, "urn:authdata-radius-avp"
 630 };
 631 #endif
 632
 633 /*
 634  * Unfortunately extracting an AD-KDCIssued authorization data element
 635  * is pretty implementation-dependent. It's not possible to verify the
 636  * signature ourselves because the ticket session key is not exposed
 637  * outside GSS. In an ideal world, all AD-KDCIssued elements would be
 638  * verified by the Kerberos library and authentication would fail if
 639  * verification failed. We're not quite there yet and as a result have
 640  * to go through some hoops to get this to work. The alternative would
 641  * be to sign the authorization data with our long-term key, but it
 642  * seems a pity to compromise the design because of current implementation
 643  * limitations.
 644  *
 645  * (Specifically, the hoops involve a libkrb5 authorisation data plugin
 646  * that exposes the verified and serialised attribute context through
 647  * the Kerberos GSS mechanism's naming extensions API.)
 648  */
 649 static OM_uint32
 650 defrostAttrContext(OM_uint32 *minor,
 651                    gss_ctx_id_t glueContext,
 652                    gss_name_t glueName,
 653                    gss_name_t mechName)
 654 {
 655     OM_uint32 major, tmpMinor;
 656 #ifdef HAVE_HEIMDAL_VERSION
 657     gss_OID_desc oid = { 0 };
 658     gss_buffer_set_t authData = GSS_C_NO_BUFFER_SET;
 659 #else
 660     gss_buffer_desc authData = GSS_C_EMPTY_BUFFER;
 661     gss_buffer_desc authDataDisplay = GSS_C_EMPTY_BUFFER;
 662     int more = -1;
 663     int authenticated, complete;
 664 #endif
 665
 666 #ifdef HAVE_HEIMDAL_VERSION
 667     major = composeOid(minor,
 668                        GSS_KRB5_EXTRACT_AUTHZ_DATA_FROM_SEC_CONTEXT_X->elements,
 669                        GSS_KRB5_EXTRACT_AUTHZ_DATA_FROM_SEC_CONTEXT_X->length,
 670                        KRB5_AUTHDATA_RADIUS_AVP, &oid);
 671     if (GSS_ERROR(major))
 672         return major;
 673
 674     /* XXX we are assuming that this verifies AD-KDCIssued signature */
 675     major = gssInquireSecContextByOid(minor, glueContext,
 676                                       &oid, &authData);
 677     if (major == GSS_S_COMPLETE) {
 678         if (authData == GSS_C_NO_BUFFER_SET || authData->count != 1)
 679             major = GSS_S_FAILURE;
 680         else
 681             major = gssEapImportAttrContext(minor, authData->elements, mechName);
 682     } else if (major == GSS_S_FAILURE && *minor == ENOENT) {
 683         /* This is the equivalent of GSS_S_UNAVAILABLE for MIT attr APIs */
 684         *minor = 0;
 685         major = GSS_S_COMPLETE;
 686     }
 687
 688     gss_release_buffer_set(&tmpMinor, &authData);
 689     GSSEAP_FREE(oid.elements);
 690 #else
 691     major = gssGetNameAttribute(minor, glueName, &radiusAvpKrbAttr,
 692                                 &authenticated, &complete,
 693                                 &authData, &authDataDisplay, &more);
 694     if (major == GSS_S_COMPLETE) {
 695         if (authenticated == 0)
 696             major = GSS_S_BAD_NAME;
 697         else
 698             major = gssEapImportAttrContext(minor, &authData, mechName);
 699     } else if (major == GSS_S_UNAVAILABLE) {
 700         major = GSS_S_COMPLETE;
 701     }
 702
 703     gss_release_buffer(&tmpMinor, &authData);
 704     gss_release_buffer(&tmpMinor, &authDataDisplay);
 705 #endif /* HAVE_HEIMDAL_VERSION */
 706
 707     return major;
 708 }
 709
 710 /*
 711  * Convert a mechanism glue to an EAP mechanism name by displaying and
 712  * importing it. This also handles the RADIUS attributes.
 713  */
 714 OM_uint32
 715 gssEapGlueToMechName(OM_uint32 *minor,
 716                      gss_ctx_id_t glueContext,
 717                      gss_name_t glueName,
 718                      gss_name_t *pMechName)
 719 {
 720     OM_uint32 major, tmpMinor;
 721     gss_buffer_desc nameBuf = GSS_C_EMPTY_BUFFER;
 722
 723     *pMechName = GSS_C_NO_NAME;
 724
 725     major = gssDisplayName(minor, glueName, &nameBuf, NULL);
 726     if (GSS_ERROR(major))
 727         goto cleanup;
 728
 729     major = gssEapImportName(minor, &nameBuf, GSS_C_NT_USER_NAME,
 730                              pMechName);
 731     if (GSS_ERROR(major))
 732         goto cleanup;
 733
 734     major = defrostAttrContext(minor, glueContext, glueName, *pMechName);
 735     if (GSS_ERROR(major))
 736         goto cleanup;
 737
 738 cleanup:
 739     if (GSS_ERROR(major)) {
 740         gssReleaseName(&tmpMinor, pMechName);
 741         *pMechName = GSS_C_NO_NAME;
 742     }
 743
 744     gss_release_buffer(&tmpMinor, &nameBuf);
 745
 746     return major;
 747 }
 748
 749 /*
 750  * Convert an EAP mechanism name to a mechanism glue name by displaying
 751  * and importing it.
 752  */
 753 OM_uint32
 754 gssEapMechToGlueName(OM_uint32 *minor,
 755                      gss_name_t mechName,
 756                      gss_name_t *pGlueName)
 757 {
 758     OM_uint32 major, tmpMinor;
 759     gss_buffer_desc nameBuf = GSS_C_EMPTY_BUFFER;
 760
 761     *pGlueName = GSS_C_NO_NAME;
 762
 763     major = gssEapDisplayName(minor, mechName, &nameBuf, NULL);
 764     if (GSS_ERROR(major))
 765         goto cleanup;
 766
 767     major = gssImportName(minor, &nameBuf, GSS_C_NT_USER_NAME,
 768                           pGlueName);
 769     if (GSS_ERROR(major))
 770         goto cleanup;
 771
 772 cleanup:
 773     gss_release_buffer(&tmpMinor, &nameBuf);
 774
 775     return major;
 776 }
 777
 778 /*
 779  * Suck out the analgous elements of a Kerberos GSS context into an EAP
 780  * one so that the application doesn't know the difference.
 781  */
 782 OM_uint32
 783 gssEapReauthComplete(OM_uint32 *minor,
 784                     gss_ctx_id_t ctx,
 785                     gss_cred_id_t cred,
 786                     const gss_OID mech,
 787                     OM_uint32 timeRec)
 788 {
 789     OM_uint32 major, tmpMinor;
 790     gss_buffer_set_t keyData = GSS_C_NO_BUFFER_SET;
 791     krb5_context krbContext = NULL;
 792 #ifdef HAVE_HEIMDAL_VERSION
 793     krb5_storage *sp = NULL;
 794 #endif
 795
 796     GSSEAP_KRB_INIT(&krbContext);
 797
 798     if (!oidEqual(mech, gss_mech_krb5)) {
 799         major = GSS_S_BAD_MECH;
 800         goto cleanup;
 801     }
 802
 803     /* Get the raw subsession key and encryption type */
 804 #ifdef HAVE_HEIMDAL_VERSION
 805 #define KRB_GSS_SUBKEY_COUNT    1 /* encoded session key */
 806     major = gssInquireSecContextByOid(minor, ctx->kerberosCtx,
 807                                       GSS_KRB5_GET_SUBKEY_X, &keyData);
 808 #else
 809 #define KRB_GSS_SUBKEY_COUNT    2 /* raw session key, enctype OID */
 810     major = gssInquireSecContextByOid(minor, ctx->kerberosCtx,
 811                                       GSS_C_INQ_SSPI_SESSION_KEY, &keyData);
 812 #endif
 813     if (GSS_ERROR(major))
 814         goto cleanup;
 815
 816     if (keyData == GSS_C_NO_BUFFER_SET || keyData->count < KRB_GSS_SUBKEY_COUNT) {
 817         *minor = GSSEAP_KEY_UNAVAILABLE;
 818         major = GSS_S_FAILURE;
 819         goto cleanup;
 820     }
 821
 822 #ifdef HAVE_HEIMDAL_VERSION
 823     sp = krb5_storage_from_mem(keyData->elements[0].value,
 824                                keyData->elements[0].length);
 825     if (sp == NULL) {
 826         *minor = ENOMEM;
 827         major = GSS_S_FAILURE;
 828         goto cleanup;
 829     }
 830
 831     *minor = krb5_ret_keyblock(sp, &ctx->rfc3961Key);
 832     if (*minor != 0) {
 833         major = GSS_S_FAILURE;
 834         goto cleanup;
 835     }
 836 #else
 837     {
 838         gss_OID_desc oid;
 839         int suffix;
 840
 841         oid.length = keyData->elements[1].length;
 842         oid.elements = keyData->elements[1].value;
 843
 844         /* GSS_KRB5_SESSION_KEY_ENCTYPE_OID */
 845         major = decomposeOid(minor,
 846                              "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02\x04",
 847                              10, &oid, &suffix);
 848         if (GSS_ERROR(major))
 849             goto cleanup;
 850
 851         ctx->encryptionType = suffix;
 852     }
 853
 854     {
 855         krb5_keyblock key;
 856
 857         KRB_KEY_LENGTH(&key) = keyData->elements[0].length;
 858         KRB_KEY_DATA(&key)   = keyData->elements[0].value;
 859         KRB_KEY_TYPE(&key)   = ctx->encryptionType;
 860
 861         *minor = krb5_copy_keyblock_contents(krbContext,
 862                                              &key, &ctx->rfc3961Key);
 863         if (*minor != 0) {
 864             major = GSS_S_FAILURE;
 865             goto cleanup;
 866         }
 867     }
 868 #endif /* HAVE_HEIMDAL_VERSION */
 869
 870     major = rfc3961ChecksumTypeForKey(minor, &ctx->rfc3961Key,
 871                                       &ctx->checksumType);
 872     if (GSS_ERROR(major))
 873         goto cleanup;
 874
 875     if (timeRec != GSS_C_INDEFINITE)
 876         ctx->expiryTime = time(NULL) + timeRec;
 877
 878     /* Initialize our sequence state */
 879     major = sequenceInit(minor,
 880                          &ctx->seqState, ctx->recvSeq,
 881                          ((ctx->gssFlags & GSS_C_REPLAY_FLAG) != 0),
 882                          ((ctx->gssFlags & GSS_C_SEQUENCE_FLAG) != 0),
 883                          TRUE);
 884     if (GSS_ERROR(major))
 885         goto cleanup;
 886
 887     major = GSS_S_COMPLETE;
 888
 889 cleanup:
 890 #ifdef HAVE_HEIMDAL_VERSION
 891     if (sp != NULL)
 892         krb5_storage_free(sp);
 893 #endif
 894     gss_release_buffer_set(&tmpMinor, &keyData);
 895
 896     return major;
 897 }
 898
 899 /*
 900  * The remainder of this file consists of wrappers so we can call into the
 901  * mechanism glue without calling ourselves.
 902  */
 903 static OM_uint32
 904 (*gssInitSecContextNext)(OM_uint32 *,
 905                          gss_cred_id_t,
 906                          gss_ctx_id_t *,
 907                          gss_name_t,
 908                          gss_OID,
 909                          OM_uint32,
 910                          OM_uint32,
 911                          gss_channel_bindings_t,
 912                          gss_buffer_t,
 913                          gss_OID *,
 914                          gss_buffer_t,
 915                          OM_uint32 *,
 916                          OM_uint32 *);
 917
 918 static OM_uint32
 919 (*gssAcceptSecContextNext)(OM_uint32 *,
 920                            gss_ctx_id_t *,
 921                            gss_cred_id_t,
 922                            gss_buffer_t,
 923                            gss_channel_bindings_t,
 924                            gss_name_t *,
 925                            gss_OID *,
 926                            gss_buffer_t,
 927                            OM_uint32 *,
 928                            OM_uint32 *,
 929                            gss_cred_id_t *);
 930
 931 static OM_uint32
 932 (*gssReleaseCredNext)(OM_uint32 *, gss_cred_id_t *);
 933
 934 static OM_uint32
 935 (*gssReleaseNameNext)(OM_uint32 *, gss_name_t *);
 936
 937 static OM_uint32
 938 (*gssInquireSecContextByOidNext)(OM_uint32 *,
 939                                  const gss_ctx_id_t,
 940                                  const gss_OID,
 941                                  gss_buffer_set_t *);
 942
 943 static OM_uint32
 944 (*gssDeleteSecContextNext)(OM_uint32 *,
 945                           gss_ctx_id_t *,
 946                           gss_buffer_t);
 947
 948 static OM_uint32
 949 (*gssDisplayNameNext)(OM_uint32 *,
 950                       gss_name_t,
 951                       gss_buffer_t,
 952                       gss_OID *);
 953
 954 static OM_uint32
 955 (*gssImportNameNext)(OM_uint32 *,
 956                      gss_buffer_t,
 957                      gss_OID,
 958                      gss_name_t *);
 959
 960 static OM_uint32
 961 (*gssStoreCredNext)(OM_uint32 *,
 962                     const gss_cred_id_t,
 963                     gss_cred_usage_t,
 964                     const gss_OID,
 965                     OM_uint32,
 966                     OM_uint32,
 967                     gss_OID_set *,
 968                     gss_cred_usage_t *);
 969
 970 static OM_uint32
 971 (*gssGetNameAttributeNext)(OM_uint32 *,
 972                           gss_name_t,
 973                           gss_buffer_t,
 974                           int *,
 975                           int *,
 976                           gss_buffer_t,
 977                           gss_buffer_t,
 978                           int *);
 979
 980 #define NEXT_SYMBOL(local, global)  do {        \
 981         ((local) = dlsym(RTLD_NEXT, (global))); \
 982         if ((local) == NULL) {                  \
 983             *minor = GSSEAP_NO_MECHGLUE_SYMBOL; \
 984             major = GSS_S_UNAVAILABLE;          \
 985             /* but continue */                  \
 986         }                                       \
 987     } while (0)
 988
 989 OM_uint32
 990 gssEapReauthInitialize(OM_uint32 *minor)
 991 {
 992     OM_uint32 major = GSS_S_COMPLETE;
 993
 994     NEXT_SYMBOL(gssInitSecContextNext,         "gss_init_sec_context");
 995     NEXT_SYMBOL(gssAcceptSecContextNext,       "gss_accept_sec_context");
 996     NEXT_SYMBOL(gssReleaseCredNext,            "gss_release_cred");
 997     NEXT_SYMBOL(gssReleaseNameNext,            "gss_release_name");
 998     NEXT_SYMBOL(gssInquireSecContextByOidNext, "gss_inquire_sec_context_by_oid");
 999     NEXT_SYMBOL(gssDeleteSecContextNext,       "gss_delete_sec_context");
1000     NEXT_SYMBOL(gssDisplayNameNext,            "gss_display_name");
1001     NEXT_SYMBOL(gssImportNameNext,             "gss_import_name");
1002     NEXT_SYMBOL(gssStoreCredNext,              "gss_store_cred");
1003     NEXT_SYMBOL(gssGetNameAttributeNext,       "gss_get_name_attribute");
1004
1005     return major;
1006 }
1007
1008 OM_uint32
1009 gssInitSecContext(OM_uint32 *minor,
1010                   gss_cred_id_t cred,
1011                   gss_ctx_id_t *context_handle,
1012                   gss_name_t target_name,
1013                   gss_OID mech_type,
1014                   OM_uint32 req_flags,
1015                   OM_uint32 time_req,
1016                   gss_channel_bindings_t input_chan_bindings,
1017                   gss_buffer_t input_token,
1018                   gss_OID *actual_mech_type,
1019                   gss_buffer_t output_token,
1020                   OM_uint32 *ret_flags,
1021                   OM_uint32 *time_rec)
1022 {
1023     if (gssInitSecContextNext == NULL) {
1024         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1025         return GSS_S_UNAVAILABLE;
1026     }
1027
1028     return gssInitSecContextNext(minor, cred, context_handle,
1029                                  target_name, mech_type, req_flags,
1030                                  time_req, input_chan_bindings,
1031                                  input_token, actual_mech_type,
1032                                  output_token, ret_flags, time_rec);
1033 }
1034
1035 OM_uint32
1036 gssAcceptSecContext(OM_uint32 *minor,
1037                     gss_ctx_id_t *context_handle,
1038                     gss_cred_id_t cred,
1039                     gss_buffer_t input_token,
1040                     gss_channel_bindings_t input_chan_bindings,
1041                     gss_name_t *src_name,
1042                     gss_OID *mech_type,
1043                     gss_buffer_t output_token,
1044                     OM_uint32 *ret_flags,
1045                     OM_uint32 *time_rec,
1046                     gss_cred_id_t *delegated_cred_handle)
1047 {
1048     if (gssAcceptSecContextNext == NULL) {
1049         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1050         return GSS_S_UNAVAILABLE;
1051     }
1052
1053     return gssAcceptSecContextNext(minor, context_handle, cred,
1054                                    input_token, input_chan_bindings,
1055                                    src_name, mech_type, output_token,
1056                                    ret_flags, time_rec, delegated_cred_handle);
1057 }
1058
1059 OM_uint32
1060 gssReleaseCred(OM_uint32 *minor,
1061                gss_cred_id_t *cred_handle)
1062 {
1063     if (gssReleaseCredNext == NULL) {
1064         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1065         return GSS_S_UNAVAILABLE;
1066     }
1067
1068     return gssReleaseCredNext(minor, cred_handle);
1069 }
1070
1071 OM_uint32
1072 gssReleaseName(OM_uint32 *minor,
1073                gss_name_t *name)
1074 {
1075     if (gssReleaseName == NULL) {
1076         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1077         return GSS_S_UNAVAILABLE;
1078     }
1079
1080     return gssReleaseNameNext(minor, name);
1081 }
1082
1083 OM_uint32
1084 gssDeleteSecContext(OM_uint32 *minor,
1085                     gss_ctx_id_t *context_handle,
1086                     gss_buffer_t output_token)
1087 {
1088     if (gssDeleteSecContextNext == NULL) {
1089         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1090         return GSS_S_UNAVAILABLE;
1091     }
1092
1093     return gssDeleteSecContextNext(minor, context_handle, output_token);
1094 }
1095
1096 static OM_uint32
1097 gssDisplayName(OM_uint32 *minor,
1098                gss_name_t name,
1099                gss_buffer_t buffer,
1100                gss_OID *name_type)
1101 {
1102     if (gssDisplayNameNext == NULL) {
1103         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1104         return GSS_S_UNAVAILABLE;
1105     }
1106
1107     return gssDisplayNameNext(minor, name, buffer, name_type);
1108 }
1109
1110 static OM_uint32
1111 gssImportName(OM_uint32 *minor,
1112               gss_buffer_t buffer,
1113               gss_OID name_type,
1114               gss_name_t *name)
1115 {
1116     if (gssImportNameNext == NULL) {
1117         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1118         return GSS_S_UNAVAILABLE;
1119     }
1120
1121     return gssImportNameNext(minor, buffer, name_type, name);
1122 }
1123
1124 OM_uint32
1125 gssInquireSecContextByOid(OM_uint32 *minor,
1126                           const gss_ctx_id_t context_handle,
1127                           const gss_OID desired_object,
1128                           gss_buffer_set_t *data_set)
1129 {
1130     if (gssInquireSecContextByOidNext == NULL) {
1131         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1132         return GSS_S_UNAVAILABLE;
1133     }
1134
1135     return gssInquireSecContextByOidNext(minor, context_handle,
1136                                          desired_object, data_set);
1137 }
1138
1139 OM_uint32
1140 gssStoreCred(OM_uint32 *minor,
1141              const gss_cred_id_t input_cred_handle,
1142              gss_cred_usage_t input_usage,
1143              const gss_OID desired_mech,
1144              OM_uint32 overwrite_cred,
1145              OM_uint32 default_cred,
1146              gss_OID_set *elements_stored,
1147              gss_cred_usage_t *cred_usage_stored)
1148 {
1149     if (gssStoreCredNext == NULL) {
1150         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1151         return GSS_S_UNAVAILABLE;
1152     }
1153
1154     return gssStoreCredNext(minor, input_cred_handle, input_usage,
1155                             desired_mech, overwrite_cred, default_cred,
1156                             elements_stored, cred_usage_stored);
1157 }
1158
1159 OM_uint32
1160 gssGetNameAttribute(OM_uint32 *minor,
1161                     gss_name_t name,
1162                     gss_buffer_t attr,
1163                     int *authenticated,
1164                     int *complete,
1165                     gss_buffer_t value,
1166                     gss_buffer_t display_value,
1167                     int *more)
1168 {
1169     if (gssGetNameAttributeNext == NULL) {
1170         *minor = GSSEAP_NO_MECHGLUE_SYMBOL;
1171         return GSS_S_UNAVAILABLE;
1172     }
1173
1174     return gssGetNameAttributeNext(minor, name, attr, authenticated, complete,
1175                                    value, display_value, more);
1176 }