accept_sec_context.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 #include "gssapiP_eap.h"
  34
  35 #ifdef GSSEAP_ENABLE_REAUTH
  36 static OM_uint32
  37 eapGssSmAcceptGssReauth(OM_uint32 *minor,
  38                         gss_ctx_id_t ctx,
  39                         gss_cred_id_t cred,
  40                         gss_buffer_t inputToken,
  41                         gss_channel_bindings_t chanBindings,
  42                         gss_buffer_t outputToken);
  43 #endif
  44
  45 /*
  46  * Mark an acceptor context as ready for cryptographic operations
  47  */
  48 static OM_uint32
  49 acceptReadyEap(OM_uint32 *minor, gss_ctx_id_t ctx, gss_cred_id_t cred)
  50 {
  51     OM_uint32 major, tmpMinor;
  52     VALUE_PAIR *vp;
  53     gss_buffer_desc nameBuf = GSS_C_EMPTY_BUFFER;
  54
  55     /* Cache encryption type derived from selected mechanism OID */
  56     major = gssEapOidToEnctype(minor, ctx->mechanismUsed,
  57                                &ctx->encryptionType);
  58     if (GSS_ERROR(major))
  59         return major;
  60
  61     gssEapReleaseName(&tmpMinor, &ctx->initiatorName);
  62
  63     major = gssEapRadiusGetRawAvp(minor, ctx->acceptorCtx.vps,
  64                                   PW_USER_NAME, 0, &vp);
  65     if (major == GSS_S_COMPLETE) {
  66         nameBuf.length = vp->length;
  67         nameBuf.value = vp->vp_strvalue;
  68     } else {
  69         ctx->gssFlags |= GSS_C_ANON_FLAG;
  70     }
  71
  72     major = gssEapImportName(minor, &nameBuf, GSS_C_NT_USER_NAME,
  73                              &ctx->initiatorName);
  74     if (GSS_ERROR(major))
  75         return major;
  76
  77     major = gssEapRadiusGetRawAvp(minor, ctx->acceptorCtx.vps,
  78                                   PW_MS_MPPE_SEND_KEY, VENDORPEC_MS, &vp);
  79     if (GSS_ERROR(major)) {
  80         *minor = GSSEAP_KEY_UNAVAILABLE;
  81         return GSS_S_UNAVAILABLE;
  82     }
  83
  84     major = gssEapDeriveRfc3961Key(minor,
  85                                    vp->vp_octets,
  86                                    vp->length,
  87                                    ctx->encryptionType,
  88                                    &ctx->rfc3961Key);
  89     if (GSS_ERROR(major))
  90         return major;
  91
  92     major = rfc3961ChecksumTypeForKey(minor, &ctx->rfc3961Key,
  93                                        &ctx->checksumType);
  94     if (GSS_ERROR(major))
  95         return major;
  96
  97     major = sequenceInit(minor,
  98                          &ctx->seqState, ctx->recvSeq,
  99                          ((ctx->gssFlags & GSS_C_REPLAY_FLAG) != 0),
 100                          ((ctx->gssFlags & GSS_C_SEQUENCE_FLAG) != 0),
 101                          TRUE);
 102     if (GSS_ERROR(major))
 103         return major;
 104
 105     ctx->initiatorName->attrCtx = gssEapCreateAttrContext(cred, ctx);
 106
 107     return GSS_S_COMPLETE;
 108 }
 109
 110 /*
 111  * Emit a identity EAP request to force the initiator (peer) to identify
 112  * itself.
 113  */
 114 static OM_uint32
 115 eapGssSmAcceptIdentity(OM_uint32 *minor,
 116                        gss_ctx_id_t ctx,
 117                        gss_cred_id_t cred,
 118                        gss_buffer_t inputToken,
 119                        gss_channel_bindings_t chanBindings,
 120                        gss_buffer_t outputToken)
 121 {
 122     OM_uint32 major;
 123     union {
 124         struct eap_hdr pdu;
 125         unsigned char data[5];
 126     } pkt;
 127     gss_buffer_desc pktBuffer;
 128
 129     if (inputToken != GSS_C_NO_BUFFER && inputToken->length != 0)
 130         return GSS_S_DEFECTIVE_TOKEN;
 131
 132     assert(ctx->acceptorName == GSS_C_NO_NAME);
 133
 134     if (cred != GSS_C_NO_CREDENTIAL && cred->name != GSS_C_NO_NAME) {
 135         major = gssEapDuplicateName(minor, cred->name, &ctx->acceptorName);
 136         if (GSS_ERROR(major))
 137             return major;
 138     }
 139
 140     pkt.pdu.code = EAP_CODE_REQUEST;
 141     pkt.pdu.identifier = 0;
 142     pkt.pdu.length = htons(sizeof(pkt.data));
 143     pkt.data[4] = EAP_TYPE_IDENTITY;
 144
 145     pktBuffer.length = sizeof(pkt.data);
 146     pktBuffer.value = pkt.data;
 147
 148     major = duplicateBuffer(minor, &pktBuffer, outputToken);
 149     if (GSS_ERROR(major))
 150         return major;
 151
 152     ctx->state = EAP_STATE_AUTHENTICATE;
 153
 154     return GSS_S_CONTINUE_NEEDED;
 155 }
 156
 157 /*
 158  * Pass the asserted acceptor identity to the authentication server.
 159  */
 160 static OM_uint32
 161 setAcceptorIdentity(OM_uint32 *minor,
 162                     gss_ctx_id_t ctx,
 163                     VALUE_PAIR **vps)
 164 {
 165     OM_uint32 major;
 166     gss_buffer_desc nameBuf;
 167     krb5_context krbContext = NULL;
 168     krb5_principal krbPrinc;
 169     struct rs_handle *rh = ctx->acceptorCtx.radHandle;
 170
 171     assert(rh != NULL);
 172
 173     /* Awaits further specification */
 174     if (ctx->acceptorName == GSS_C_NO_NAME)
 175         return GSS_S_COMPLETE;
 176
 177     GSSEAP_KRB_INIT(&krbContext);
 178
 179     krbPrinc = ctx->acceptorName->krbPrincipal;
 180     assert(krbPrinc != NULL);
 181
 182     if (krb5_princ_size(krbContext, krbPrinc) < 2)
 183         return GSS_S_BAD_NAME;
 184
 185     /* Acceptor-Service-Name */
 186     krbDataToGssBuffer(krb5_princ_component(krbContext, krbPrinc, 0), &nameBuf);
 187
 188     major = gssEapRadiusAddAvp(minor, vps,
 189                                PW_GSS_ACCEPTOR_SERVICE_NAME,
 190                                VENDORPEC_UKERNA,
 191                                &nameBuf);
 192     if (GSS_ERROR(major))
 193         return major;
 194
 195     /* Acceptor-Host-Name */
 196     krbDataToGssBuffer(krb5_princ_component(krbContext, krbPrinc, 1), &nameBuf);
 197
 198     major = gssEapRadiusAddAvp(minor, vps,
 199                                PW_GSS_ACCEPTOR_HOST_NAME,
 200                                VENDORPEC_UKERNA,
 201                                &nameBuf);
 202     if (GSS_ERROR(major))
 203         return major;
 204
 205     if (krb5_princ_size(krbContext, krbPrinc) > 2) {
 206         /* Acceptor-Service-Specific */
 207         krb5_principal_data ssiPrinc = *krbPrinc;
 208         char *ssi;
 209
 210         krb5_princ_size(krbContext, &ssiPrinc) -= 2;
 211         krb5_princ_name(krbContext, &ssiPrinc) += 2;
 212
 213         *minor = krb5_unparse_name_flags(krbContext, &ssiPrinc,
 214                                          KRB5_PRINCIPAL_UNPARSE_NO_REALM, &ssi);
 215         if (*minor != 0)
 216             return GSS_S_FAILURE;
 217
 218         nameBuf.value = ssi;
 219         nameBuf.length = strlen(ssi);
 220
 221         major = gssEapRadiusAddAvp(minor, vps,
 222                                    PW_GSS_ACCEPTOR_SERVICE_SPECIFIC,
 223                                    VENDORPEC_UKERNA,
 224                                    &nameBuf);
 225
 226         if (GSS_ERROR(major)) {
 227             krb5_free_unparsed_name(krbContext, ssi);
 228             return major;
 229         }
 230         krb5_free_unparsed_name(krbContext, ssi);
 231     }
 232
 233     krbDataToGssBuffer(krb5_princ_realm(krbContext, krbPrinc), &nameBuf);
 234     if (nameBuf.length != 0) {
 235         /* Acceptor-Realm-Name */
 236         major = gssEapRadiusAddAvp(minor, vps,
 237                                    PW_GSS_ACCEPTOR_REALM_NAME,
 238                                    VENDORPEC_UKERNA,
 239                                    &nameBuf);
 240         if (GSS_ERROR(major))
 241             return major;
 242     }
 243
 244     return GSS_S_COMPLETE;
 245 }
 246
 247 /*
 248  * Allocate a RadSec handle
 249  */
 250 static OM_uint32
 251 createRadiusHandle(OM_uint32 *minor,
 252                    gss_cred_id_t cred,
 253                    gss_ctx_id_t ctx)
 254 {
 255     struct gss_eap_acceptor_ctx *actx = &ctx->acceptorCtx;
 256     const char *configFile = RS_CONFIG_FILE;
 257     const char *configStanza = "gss-eap";
 258     struct rs_alloc_scheme ralloc;
 259     struct rs_error *err;
 260
 261     assert(actx->radHandle == NULL);
 262     assert(actx->radConn == NULL);
 263
 264     if (rs_context_create(&actx->radHandle, RS_DICT_FILE) != 0) {
 265         *minor = GSSEAP_RADSEC_INIT_FAILURE;
 266         return GSS_S_FAILURE;
 267     }
 268
 269     if (cred != GSS_C_NO_CREDENTIAL) {
 270         if (cred->radiusConfigFile != NULL)
 271             configFile = cred->radiusConfigFile;
 272         if (cred->radiusConfigStanza != NULL)
 273             configStanza = cred->radiusConfigStanza;
 274     }
 275
 276     ralloc.calloc  = GSSEAP_CALLOC;
 277     ralloc.malloc  = GSSEAP_MALLOC;
 278     ralloc.free    = GSSEAP_FREE;
 279     ralloc.realloc = GSSEAP_REALLOC;
 280
 281     rs_context_set_alloc_scheme(actx->radHandle, &ralloc);
 282
 283     if (rs_context_read_config(actx->radHandle, configFile) != 0) {
 284         err = rs_err_ctx_pop(actx->radHandle);
 285         goto fail;
 286     }
 287
 288     if (rs_conn_create(actx->radHandle, &actx->radConn, configStanza) != 0) {
 289         err = rs_err_conn_pop(actx->radConn);
 290         goto fail;
 291     }
 292
 293     /* XXX TODO rs_conn_select_server does not exist yet */
 294 #if 0
 295     if (actx->radServer != NULL) {
 296         if (rs_conn_select_server(actx->radConn, actx->radServer) != 0) {
 297             err = rs_err_conn_pop(actx->radConn);
 298             goto fail;
 299         }
 300     }
 301 #endif
 302
 303     *minor = 0;
 304     return GSS_S_COMPLETE;
 305
 306 fail:
 307     return gssEapRadiusMapError(minor, err);
 308 }
 309
 310 /*
 311  * Process a EAP response from the initiator.
 312  */
 313 static OM_uint32
 314 eapGssSmAcceptAuthenticate(OM_uint32 *minor,
 315                            gss_ctx_id_t ctx,
 316                            gss_cred_id_t cred,
 317                            gss_buffer_t inputToken,
 318                            gss_channel_bindings_t chanBindings,
 319                            gss_buffer_t outputToken)
 320 {
 321     OM_uint32 major, tmpMinor;
 322     struct rs_handle *rh;
 323     struct rs_connection *rconn;
 324     struct rs_request *request = NULL;
 325     struct rs_packet *req = NULL, *resp = NULL;
 326     struct radius_packet *frreq, *frresp;
 327     int sendAcceptorIdentity = 0;
 328
 329     if (ctx->acceptorCtx.radHandle == NULL) {
 330         /* May be NULL from an imported partial context */
 331         major = createRadiusHandle(minor, cred, ctx);
 332         if (GSS_ERROR(major))
 333             goto cleanup;
 334
 335         sendAcceptorIdentity = 1;
 336     }
 337
 338     rh = ctx->acceptorCtx.radHandle;
 339     rconn = ctx->acceptorCtx.radConn;
 340
 341     if (rs_packet_create_acc_request(rconn, &req, NULL, NULL) != 0) {
 342         major = gssEapRadiusMapError(minor, rs_err_conn_pop(rconn));
 343         goto cleanup;
 344     }
 345     frreq = rs_packet_frpkt(req);
 346
 347     if (sendAcceptorIdentity) {
 348         major = setAcceptorIdentity(minor, ctx, &frreq->vps);
 349         if (GSS_ERROR(major))
 350             goto cleanup;
 351     }
 352
 353     major = gssEapRadiusAddAvp(minor, &frreq->vps,
 354                                PW_EAP_MESSAGE, 0, inputToken);
 355     if (GSS_ERROR(major))
 356         goto cleanup;
 357
 358     if (ctx->acceptorCtx.state.length != 0) {
 359         major = gssEapRadiusAddAvp(minor, &frreq->vps, PW_STATE, 0,
 360                                    &ctx->acceptorCtx.state);
 361         if (GSS_ERROR(major))
 362             goto cleanup;
 363
 364         gss_release_buffer(&tmpMinor, &ctx->acceptorCtx.state);
 365     }
 366
 367     if (rs_request_create(rconn, &request) != 0 ||
 368         rs_request_send(request, req, &resp) != 0) {
 369         major = gssEapRadiusMapError(minor, rs_err_conn_pop(rconn));
 370         goto cleanup;
 371     }
 372
 373     assert(resp != NULL);
 374
 375     frresp = rs_packet_frpkt(resp);
 376     switch (frresp->code) {
 377     case PW_AUTHENTICATION_ACK:
 378     case PW_ACCESS_CHALLENGE:
 379         major = GSS_S_CONTINUE_NEEDED;
 380         break;
 381     case PW_AUTHENTICATION_REJECT:
 382         *minor = GSSEAP_RADIUS_AUTH_FAILURE;
 383         major = GSS_S_DEFECTIVE_CREDENTIAL;
 384         goto cleanup;
 385         break;
 386     default:
 387         *minor = GSSEAP_UNKNOWN_RADIUS_CODE;
 388         major = GSS_S_FAILURE;
 389         goto cleanup;
 390         break;
 391     }
 392
 393     major = gssEapRadiusGetAvp(minor, frresp->vps, PW_EAP_MESSAGE, 0,
 394                                outputToken, TRUE);
 395     if (major == GSS_S_UNAVAILABLE && frresp->code == PW_ACCESS_CHALLENGE) {
 396         *minor = GSSEAP_MISSING_EAP_REQUEST;
 397         major = GSS_S_DEFECTIVE_TOKEN;
 398         goto cleanup;
 399     } else if (GSS_ERROR(major))
 400         goto cleanup;
 401
 402     if (frresp->code == PW_ACCESS_CHALLENGE) {
 403         major = gssEapRadiusGetAvp(minor, frresp->vps, PW_STATE, 0,
 404                                    &ctx->acceptorCtx.state, TRUE);
 405         if (GSS_ERROR(major) && *minor != GSSEAP_NO_SUCH_ATTR)
 406             goto cleanup;
 407     } else {
 408         ctx->acceptorCtx.vps = frresp->vps;
 409         frresp->vps = NULL;
 410
 411         rs_conn_destroy(ctx->acceptorCtx.radConn);
 412         ctx->acceptorCtx.radConn = NULL;
 413
 414         major = acceptReadyEap(minor, ctx, cred);
 415         if (GSS_ERROR(major))
 416             goto cleanup;
 417
 418         ctx->state = EAP_STATE_EXTENSIONS_REQ;
 419     }
 420
 421     major = GSS_S_CONTINUE_NEEDED;
 422
 423 cleanup:
 424     rs_request_destroy(request);
 425
 426     return major;
 427 }
 428
 429 static OM_uint32
 430 eapGssSmAcceptExtensionsReq(OM_uint32 *minor,
 431                             gss_ctx_id_t ctx,
 432                             gss_cred_id_t cred,
 433                             gss_buffer_t inputToken,
 434                             gss_channel_bindings_t chanBindings,
 435                             gss_buffer_t outputToken)
 436 {
 437     OM_uint32 major;
 438
 439     major = gssEapVerifyExtensions(minor, cred, ctx, chanBindings, inputToken);
 440     if (GSS_ERROR(major))
 441         return major;
 442
 443     outputToken->length = 0;
 444     outputToken->value = NULL;
 445
 446     ctx->state = EAP_STATE_EXTENSIONS_RESP;
 447
 448     return GSS_S_CONTINUE_NEEDED;
 449 }
 450
 451 static OM_uint32
 452 eapGssSmAcceptExtensionsResp(OM_uint32 *minor,
 453                              gss_ctx_id_t ctx,
 454                              gss_cred_id_t cred,
 455                              gss_buffer_t inputToken,
 456                              gss_channel_bindings_t chanBindings,
 457                              gss_buffer_t outputToken)
 458 {
 459     OM_uint32 major;
 460
 461     major = gssEapMakeExtensions(minor, cred, ctx, chanBindings, outputToken);
 462     if (GSS_ERROR(major))
 463         return major;
 464
 465     ctx->state = EAP_STATE_ESTABLISHED;
 466
 467     return GSS_S_COMPLETE;
 468 }
 469
 470 static OM_uint32
 471 eapGssSmAcceptEstablished(OM_uint32 *minor,
 472                           gss_ctx_id_t ctx,
 473                           gss_cred_id_t cred,
 474                           gss_buffer_t inputToken,
 475                           gss_channel_bindings_t chanBindings,
 476                           gss_buffer_t outputToken)
 477 {
 478     /* Called with already established context */
 479     *minor = GSSEAP_CONTEXT_ESTABLISHED;
 480     return GSS_S_BAD_STATUS;
 481 }
 482
 483 static OM_uint32
 484 makeErrorToken(OM_uint32 *minor,
 485                OM_uint32 majorStatus,
 486                OM_uint32 minorStatus,
 487                gss_buffer_t outputToken)
 488 {
 489     unsigned char errorData[8];
 490     gss_buffer_desc errorBuffer;
 491
 492     assert(GSS_ERROR(majorStatus));
 493
 494     /*
 495      * Only return error codes that the initiator could have caused,
 496      * to avoid information leakage.
 497      */
 498     switch (minorStatus) {
 499     case GSSEAP_WRONG_SIZE:
 500     case GSSEAP_WRONG_MECH:
 501     case GSSEAP_BAD_TOK_HEADER:
 502     case GSSEAP_BAD_DIRECTION:
 503     case GSSEAP_WRONG_TOK_ID:
 504     case GSSEAP_CRIT_EXT_UNAVAILABLE:
 505     case GSSEAP_MISSING_REQUIRED_EXT:
 506     case GSSEAP_KEY_UNAVAILABLE:
 507     case GSSEAP_KEY_TOO_SHORT:
 508     case GSSEAP_RADIUS_AUTH_FAILURE:
 509     case GSSEAP_UNKNOWN_RADIUS_CODE:
 510     case GSSEAP_MISSING_EAP_REQUEST:
 511         break;
 512     default:
 513         if (IS_RADIUS_ERROR(minorStatus))
 514             /* Squash RADIUS error codes */
 515             minorStatus = GSSEAP_GENERIC_RADIUS_ERROR;
 516         else
 517             /* Don't return system error codes */
 518             return GSS_S_COMPLETE;
 519     }
 520
 521     minorStatus -= ERROR_TABLE_BASE_eapg;
 522
 523     store_uint32_be(majorStatus, &errorData[0]);
 524     store_uint32_be(minorStatus, &errorData[4]);
 525
 526     errorBuffer.length = sizeof(errorData);
 527     errorBuffer.value = errorData;
 528
 529     return duplicateBuffer(minor, &errorBuffer, outputToken);
 530 }
 531
 532 static struct gss_eap_acceptor_sm {
 533     enum gss_eap_token_type inputTokenType;
 534     enum gss_eap_token_type outputTokenType;
 535     OM_uint32 (*processToken)(OM_uint32 *,
 536                               gss_ctx_id_t,
 537                               gss_cred_id_t,
 538                               gss_buffer_t,
 539                               gss_channel_bindings_t,
 540                               gss_buffer_t);
 541 } eapGssAcceptorSm[] = {
 542     { TOK_TYPE_EAP_RESP,    TOK_TYPE_EAP_REQ,       eapGssSmAcceptIdentity           },
 543     { TOK_TYPE_EAP_RESP,    TOK_TYPE_EAP_REQ,       eapGssSmAcceptAuthenticate       },
 544     { TOK_TYPE_EXT_REQ,     TOK_TYPE_NONE,          eapGssSmAcceptExtensionsReq      },
 545     { TOK_TYPE_NONE,        TOK_TYPE_EXT_RESP,      eapGssSmAcceptExtensionsResp     },
 546     { TOK_TYPE_NONE,        TOK_TYPE_NONE,          eapGssSmAcceptEstablished        },
 547     { TOK_TYPE_NONE,        TOK_TYPE_CONTEXT_ERR,   NULL                             },
 548 #ifdef GSSEAP_ENABLE_REAUTH
 549     { TOK_TYPE_GSS_REAUTH,  TOK_TYPE_GSS_REAUTH,    eapGssSmAcceptGssReauth          },
 550 #endif
 551 };
 552
 553 OM_uint32
 554 gss_accept_sec_context(OM_uint32 *minor,
 555                        gss_ctx_id_t *context_handle,
 556                        gss_cred_id_t cred,
 557                        gss_buffer_t input_token,
 558                        gss_channel_bindings_t input_chan_bindings,
 559                        gss_name_t *src_name,
 560                        gss_OID *mech_type,
 561                        gss_buffer_t output_token,
 562                        OM_uint32 *ret_flags,
 563                        OM_uint32 *time_rec,
 564                        gss_cred_id_t *delegated_cred_handle)
 565 {
 566     OM_uint32 major;
 567     OM_uint32 tmpMajor, tmpMinor;
 568     gss_ctx_id_t ctx = *context_handle;
 569     struct gss_eap_acceptor_sm *sm = NULL;
 570     gss_buffer_desc innerInputToken = GSS_C_EMPTY_BUFFER;
 571     gss_buffer_desc innerOutputToken = GSS_C_EMPTY_BUFFER;
 572     enum gss_eap_token_type tokType;
 573     int initialContextToken = 0;
 574
 575     *minor = 0;
 576
 577     output_token->length = 0;
 578     output_token->value = NULL;
 579
 580     if (input_token == GSS_C_NO_BUFFER || input_token->length == 0) {
 581         return GSS_S_DEFECTIVE_TOKEN;
 582     }
 583
 584     if (ctx == GSS_C_NO_CONTEXT) {
 585         major = gssEapAllocContext(minor, &ctx);
 586         if (GSS_ERROR(major))
 587             return major;
 588
 589         initialContextToken = 1;
 590         *context_handle = ctx;
 591     }
 592
 593     GSSEAP_MUTEX_LOCK(&ctx->mutex);
 594
 595     /* Validate and lock credentials */
 596     if (cred != GSS_C_NO_CREDENTIAL) {
 597         GSSEAP_MUTEX_LOCK(&cred->mutex);
 598
 599         if ((cred->flags & CRED_FLAG_ACCEPT) == 0) {
 600             *minor = GSSEAP_CRED_USAGE_MISMATCH;
 601             major = GSS_S_NO_CRED;
 602             goto cleanup;
 603         }
 604     }
 605
 606     sm = &eapGssAcceptorSm[ctx->state];
 607
 608     major = gssEapVerifyToken(minor, ctx, input_token,
 609                               &tokType, &innerInputToken);
 610     if (GSS_ERROR(major))
 611         goto cleanup;
 612
 613     if (!gssEapCredAvailable(cred, ctx->mechanismUsed)) {
 614         *minor = GSSEAP_WRONG_MECH;
 615         major = GSS_S_BAD_MECH;
 616         goto cleanup;
 617     }
 618
 619 #ifdef GSSEAP_ENABLE_REAUTH
 620     /*
 621      * If we're built with fast reauthentication support, it's valid
 622      * for an initiator to send a GSS reauthentication token as its
 623      * initial context token, causing us to short-circuit the state
 624      * machine and process Kerberos GSS messages instead.
 625      */
 626     if (tokType == TOK_TYPE_GSS_REAUTH && initialContextToken) {
 627         ctx->state = EAP_STATE_KRB_REAUTH_GSS;
 628     } else
 629 #endif
 630     if (tokType != sm->inputTokenType) {
 631         *minor = GSSEAP_WRONG_TOK_ID;
 632         major = GSS_S_DEFECTIVE_TOKEN;
 633         goto cleanup;
 634     }
 635
 636     do {
 637         sm = &eapGssAcceptorSm[ctx->state];
 638
 639         major = (sm->processToken)(minor,
 640                                    ctx,
 641                                    cred,
 642                                    &innerInputToken,
 643                                    input_chan_bindings,
 644                                    &innerOutputToken);
 645         if (GSS_ERROR(major)) {
 646             /* Possibly generate an error token */
 647             tmpMajor = makeErrorToken(&tmpMinor, major, *minor, &innerOutputToken);
 648             if (GSS_ERROR(tmpMajor)) {
 649                 major = tmpMajor;
 650                 goto cleanup;
 651             }
 652
 653             sm = &eapGssAcceptorSm[EAP_STATE_ERROR];
 654             goto send_token;
 655         }
 656     } while (major == GSS_S_CONTINUE_NEEDED && innerOutputToken.length == 0);
 657
 658     if (mech_type != NULL) {
 659         if (!gssEapInternalizeOid(ctx->mechanismUsed, mech_type))
 660             duplicateOid(&tmpMinor, ctx->mechanismUsed, mech_type);
 661     }
 662     if (ret_flags != NULL)
 663         *ret_flags = ctx->gssFlags;
 664     if (delegated_cred_handle != NULL)
 665         *delegated_cred_handle = GSS_C_NO_CREDENTIAL;
 666
 667     if (major == GSS_S_COMPLETE) {
 668         if (src_name != NULL && ctx->initiatorName != GSS_C_NO_NAME) {
 669             major = gssEapDuplicateName(&tmpMinor, ctx->initiatorName, src_name);
 670             if (GSS_ERROR(major))
 671                 goto cleanup;
 672         }
 673         if (time_rec != NULL)
 674             gssEapContextTime(&tmpMinor, ctx, time_rec);
 675     }
 676
 677     assert(ctx->state == EAP_STATE_ESTABLISHED || major == GSS_S_CONTINUE_NEEDED);
 678
 679 send_token:
 680     if (innerOutputToken.value != NULL) {
 681         tmpMajor = gssEapMakeToken(&tmpMinor, ctx, &innerOutputToken,
 682                                    sm->outputTokenType, output_token);
 683         if (GSS_ERROR(tmpMajor)) {
 684             major = tmpMajor;
 685             *minor = tmpMinor;
 686             goto cleanup;
 687         }
 688     }
 689
 690 cleanup:
 691     if (cred != GSS_C_NO_CREDENTIAL)
 692         GSSEAP_MUTEX_UNLOCK(&cred->mutex);
 693     GSSEAP_MUTEX_UNLOCK(&ctx->mutex);
 694
 695     if (GSS_ERROR(major))
 696         gssEapReleaseContext(&tmpMinor, context_handle);
 697
 698     gss_release_buffer(&tmpMinor, &innerOutputToken);
 699
 700     return major;
 701 }
 702
 703 #ifdef GSSEAP_ENABLE_REAUTH
 704 static OM_uint32
 705 acceptReadyKrb(OM_uint32 *minor,
 706                gss_ctx_id_t ctx,
 707                gss_cred_id_t cred,
 708                const gss_name_t initiator,
 709                const gss_OID mech,
 710                OM_uint32 timeRec)
 711 {
 712     OM_uint32 major;
 713
 714     major = gssEapGlueToMechName(minor, initiator, &ctx->initiatorName);
 715     if (GSS_ERROR(major))
 716         return major;
 717
 718     if (cred != GSS_C_NO_CREDENTIAL && cred->name != GSS_C_NO_NAME) {
 719         major = gssEapDuplicateName(minor, cred->name, &ctx->acceptorName);
 720         if (GSS_ERROR(major))
 721             return major;
 722     }
 723
 724     major = gssEapReauthComplete(minor, ctx, cred, mech, timeRec);
 725     if (GSS_ERROR(major))
 726         return major;
 727
 728     ctx->state = EAP_STATE_ESTABLISHED;
 729
 730     return GSS_S_COMPLETE;
 731 }
 732
 733 static OM_uint32
 734 eapGssSmAcceptGssReauth(OM_uint32 *minor,
 735                         gss_ctx_id_t ctx,
 736                         gss_cred_id_t cred,
 737                         gss_buffer_t inputToken,
 738                         gss_channel_bindings_t chanBindings,
 739                         gss_buffer_t outputToken)
 740 {
 741     OM_uint32 major, tmpMinor;
 742     gss_cred_id_t krbCred = GSS_C_NO_CREDENTIAL;
 743     gss_name_t krbInitiator = GSS_C_NO_NAME;
 744     gss_OID mech = GSS_C_NO_OID;
 745     OM_uint32 gssFlags, timeRec = GSS_C_INDEFINITE;
 746
 747     ctx->flags |= CTX_FLAG_KRB_REAUTH_GSS;
 748
 749     if (cred != GSS_C_NO_CREDENTIAL)
 750         krbCred = cred->krbCred;
 751
 752     major = gssAcceptSecContext(minor,
 753                                 &ctx->kerberosCtx,
 754                                 krbCred,
 755                                 inputToken,
 756                                 chanBindings,
 757                                 &krbInitiator,
 758                                 &mech,
 759                                 outputToken,
 760                                 &gssFlags,
 761                                 &timeRec,
 762                                 NULL);
 763     if (major == GSS_S_COMPLETE) {
 764         major = acceptReadyKrb(minor, ctx, cred,
 765                                krbInitiator, mech, timeRec);
 766     }
 767
 768     ctx->gssFlags = gssFlags;
 769
 770     gssReleaseName(&tmpMinor, &krbInitiator);
 771
 772     return major;
 773 }
 774 #endif /* GSSEAP_ENABLE_REAUTH */