init_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 static OM_uint32
  36 policyVariableToFlag(enum eapol_bool_var variable)
  37 {
  38     OM_uint32 flag = 0;
  39
  40     switch (variable) {
  41     case EAPOL_eapSuccess:
  42         flag = CTX_FLAG_EAP_SUCCESS;
  43         break;
  44     case EAPOL_eapRestart:
  45         flag = CTX_FLAG_EAP_RESTART;
  46         break;
  47     case EAPOL_eapFail:
  48         flag = CTX_FLAG_EAP_FAIL;
  49         break;
  50     case EAPOL_eapResp:
  51         flag = CTX_FLAG_EAP_RESP;
  52         break;
  53     case EAPOL_eapNoResp:
  54         flag = CTX_FLAG_EAP_NO_RESP;
  55         break;
  56     case EAPOL_eapReq:
  57         flag = CTX_FLAG_EAP_REQ;
  58         break;
  59     case EAPOL_portEnabled:
  60         flag = CTX_FLAG_EAP_PORT_ENABLED;
  61         break;
  62     case EAPOL_altAccept:
  63         flag = CTX_FLAG_EAP_ALT_ACCEPT;
  64         break;
  65     case EAPOL_altReject:
  66         flag = CTX_FLAG_EAP_ALT_REJECT;
  67         break;
  68     }
  69
  70     return flag;
  71
  72 }
  73
  74 static struct eap_peer_config *
  75 peerGetConfig(void *ctx)
  76 {
  77     gss_ctx_id_t gssCtx = (gss_ctx_id_t)ctx;
  78
  79     return &gssCtx->initiatorCtx.eapPeerConfig;
  80 }
  81
  82 static Boolean
  83 peerGetBool(void *data, enum eapol_bool_var variable)
  84 {
  85     gss_ctx_id_t ctx = data;
  86     OM_uint32 flag;
  87
  88     if (ctx == GSS_C_NO_CONTEXT)
  89         return FALSE;
  90
  91     flag = policyVariableToFlag(variable);
  92
  93     return ((ctx->flags & flag) != 0);
  94 }
  95
  96 static void
  97 peerSetBool(void *data, enum eapol_bool_var variable,
  98             Boolean value)
  99 {
 100     gss_ctx_id_t ctx = data;
 101     OM_uint32 flag;
 102
 103     if (ctx == GSS_C_NO_CONTEXT)
 104         return;
 105
 106     flag = policyVariableToFlag(variable);
 107
 108     if (value)
 109         ctx->flags |= flag;
 110     else
 111         ctx->flags &= ~(flag);
 112 }
 113
 114 static unsigned int
 115 peerGetInt(void *data, enum eapol_int_var variable)
 116 {
 117     gss_ctx_id_t ctx = data;
 118
 119     if (ctx == GSS_C_NO_CONTEXT)
 120         return FALSE;
 121
 122     assert(CTX_IS_INITIATOR(ctx));
 123
 124     switch (variable) {
 125     case EAPOL_idleWhile:
 126         return ctx->initiatorCtx.idleWhile;
 127         break;
 128     }
 129
 130     return 0;
 131 }
 132
 133 static void
 134 peerSetInt(void *data, enum eapol_int_var variable,
 135            unsigned int value)
 136 {
 137     gss_ctx_id_t ctx = data;
 138
 139     if (ctx == GSS_C_NO_CONTEXT)
 140         return;
 141
 142     assert(CTX_IS_INITIATOR(ctx));
 143
 144     switch (variable) {
 145     case EAPOL_idleWhile:
 146         ctx->initiatorCtx.idleWhile = value;
 147         break;
 148     }
 149 }
 150
 151 static struct wpabuf *
 152 peerGetEapReqData(void *ctx)
 153 {
 154     gss_ctx_id_t gssCtx = (gss_ctx_id_t)ctx;
 155
 156     return &gssCtx->initiatorCtx.reqData;
 157 }
 158
 159 static void
 160 peerSetConfigBlob(void *ctx, struct wpa_config_blob *blob)
 161 {
 162 }
 163
 164 static const struct wpa_config_blob *
 165 peerGetConfigBlob(void *ctx, const char *name)
 166 {
 167     return NULL;
 168 }
 169
 170 static void
 171 peerNotifyPending(void *ctx)
 172 {
 173 }
 174
 175 static struct eapol_callbacks gssEapPolicyCallbacks = {
 176     peerGetConfig,
 177     peerGetBool,
 178     peerSetBool,
 179     peerGetInt,
 180     peerSetInt,
 181     peerGetEapReqData,
 182     peerSetConfigBlob,
 183     peerGetConfigBlob,
 184     peerNotifyPending,
 185 };
 186
 187 extern int wpa_debug_level;
 188
 189 static OM_uint32
 190 peerConfigInit(OM_uint32 *minor,
 191                gss_cred_id_t cred,
 192                gss_ctx_id_t ctx,
 193                int loadConfig)
 194 {
 195     krb5_context krbContext;
 196     struct eap_peer_config *eapPeerConfig = &ctx->initiatorCtx.eapPeerConfig;
 197     krb5_error_code code;
 198     char *identity;
 199
 200     GSSEAP_KRB_INIT(&krbContext);
 201
 202     if (loadConfig) {
 203         eapPeerConfig->fragment_size = 1024;
 204         wpa_debug_level = 0;
 205     }
 206
 207     code = krb5_unparse_name(krbContext, cred->name->krbPrincipal, &identity);
 208     if (code != 0) {
 209         *minor = code;
 210         return GSS_S_FAILURE;
 211     }
 212
 213     eapPeerConfig->identity = (unsigned char *)identity;
 214     eapPeerConfig->identity_len = strlen(identity);
 215     eapPeerConfig->password = (unsigned char *)cred->password.value;
 216     eapPeerConfig->password_len = cred->password.length;
 217
 218     return GSS_S_COMPLETE;
 219 }
 220
 221 static OM_uint32
 222 peerConfigFree(OM_uint32 *minor,
 223                gss_ctx_id_t ctx)
 224 {
 225     krb5_context krbContext;
 226     struct eap_peer_config *eapPeerConfig = &ctx->initiatorCtx.eapPeerConfig;
 227
 228     GSSEAP_KRB_INIT(&krbContext);
 229
 230     krb5_free_unparsed_name(krbContext, (char *)eapPeerConfig->identity);
 231
 232     return GSS_S_COMPLETE;
 233 }
 234
 235 static OM_uint32
 236 initReady(OM_uint32 *minor, gss_ctx_id_t ctx)
 237 {
 238     OM_uint32 major;
 239     const unsigned char *key;
 240     size_t keyLength;
 241     krb5_context krbContext;
 242
 243     GSSEAP_KRB_INIT(&krbContext);
 244
 245     /* Cache encryption type derived from selected mechanism OID */
 246     major = gssEapOidToEnctype(minor, ctx->mechanismUsed, &ctx->encryptionType);
 247     if (GSS_ERROR(major))
 248         return major;
 249
 250     if (ctx->encryptionType != ENCTYPE_NULL &&
 251         eap_key_available(ctx->initiatorCtx.eap)) {
 252         key = eap_get_eapKeyData(ctx->initiatorCtx.eap, &keyLength);
 253
 254         major = gssEapDeriveRFC3961Key(minor, key, keyLength,
 255                                        ctx->encryptionType, &ctx->rfc3961Key);
 256         if (GSS_ERROR(major))
 257             return major;
 258     } else {
 259         /*
 260          * draft-howlett-eap-gss says that integrity/confidentialty should
 261          * always be advertised as available, but if we have no keying
 262          * material it seems confusing to the caller to advertise this.
 263          */
 264         ctx->gssFlags &= ~(GSS_C_INTEG_FLAG | GSS_C_CONF_FLAG);
 265     }
 266
 267     sequenceInit(&ctx->seqState, ctx->recvSeq,
 268                  ((ctx->gssFlags & GSS_C_REPLAY_FLAG) != 0),
 269                  ((ctx->gssFlags & GSS_C_SEQUENCE_FLAG) != 0),
 270                  TRUE);
 271
 272     return GSS_S_COMPLETE;
 273 }
 274
 275 static OM_uint32
 276 eapGssSmInitAuthenticate(OM_uint32 *minor,
 277                          gss_cred_id_t cred,
 278                          gss_ctx_id_t ctx,
 279                          gss_name_t target,
 280                          gss_OID mech,
 281                          OM_uint32 reqFlags,
 282                          OM_uint32 timeReq,
 283                          gss_channel_bindings_t chanBindings,
 284                          gss_buffer_t inputToken,
 285                          gss_buffer_t outputToken)
 286 {
 287     OM_uint32 major;
 288     OM_uint32 tmpMajor, tmpMinor;
 289     time_t now;
 290     int initialContextToken = 0, code;
 291     gss_buffer_desc respBuf;
 292
 293     respBuf.length = 0;
 294     respBuf.value = NULL;
 295
 296     initialContextToken = (inputToken == GSS_C_NO_BUFFER ||
 297                            inputToken->length == 0);
 298
 299     major = peerConfigInit(minor, cred, ctx, initialContextToken);
 300     if (GSS_ERROR(major))
 301         goto cleanup;
 302
 303     if (initialContextToken) {
 304         struct eap_config eapConfig;
 305
 306         memset(&eapConfig, 0, sizeof(eapConfig));
 307         ctx->flags |= CTX_FLAG_EAP_PORT_ENABLED;
 308
 309         ctx->initiatorCtx.eap = eap_peer_sm_init(ctx,
 310                                                  &gssEapPolicyCallbacks,
 311                                                  ctx,
 312                                                  &eapConfig);
 313
 314         time(&now);
 315         if (timeReq == 0 || timeReq == GSS_C_INDEFINITE)
 316             ctx->expiryTime = 0;
 317         else
 318             ctx->expiryTime = now + timeReq;
 319
 320         major = gss_duplicate_name(minor, cred->name, &ctx->initiatorName);
 321         if (GSS_ERROR(major))
 322             goto cleanup;
 323
 324         major = gss_duplicate_name(minor, target, &ctx->acceptorName);
 325         if (GSS_ERROR(major))
 326             goto cleanup;
 327
 328         if (mech == GSS_C_NULL_OID || oidEqual(mech, GSS_EAP_MECHANISM)) {
 329             major = gssEapDefaultMech(minor, &ctx->mechanismUsed);
 330         } else if (gssEapIsConcreteMechanismOid(mech)) {
 331             if (!gssEapInternalizeOid(mech, &ctx->mechanismUsed))
 332                 major = duplicateOid(minor, mech, &ctx->mechanismUsed);
 333         } else {
 334             major = GSS_S_BAD_MECH;
 335         }
 336         if (GSS_ERROR(major))
 337             goto cleanup;
 338
 339         /* If credentials were provided, check they're usable with this mech */
 340         if (!gssEapCredAvailable(cred, ctx->mechanismUsed)) {
 341             major = GSS_S_BAD_MECH;
 342             goto cleanup;
 343         }
 344
 345         respBuf.value = ""; /* emit empty inner token */
 346         major = GSS_S_CONTINUE_NEEDED;
 347         goto cleanup;
 348     } else {
 349         ctx->flags |= CTX_FLAG_EAP_REQ; /* we have a Request from the acceptor */
 350     }
 351
 352     wpabuf_set(&ctx->initiatorCtx.reqData,
 353                inputToken->value, inputToken->length);
 354
 355     major = GSS_S_CONTINUE_NEEDED;
 356
 357     code = eap_peer_sm_step(ctx->initiatorCtx.eap);
 358     if (ctx->flags & CTX_FLAG_EAP_RESP) {
 359         struct wpabuf *resp;
 360
 361         ctx->flags &= ~(CTX_FLAG_EAP_RESP);
 362
 363         resp = eap_get_eapRespData(ctx->initiatorCtx.eap);
 364         if (resp != NULL) {
 365             respBuf.length = wpabuf_len(resp);
 366             respBuf.value = (void *)wpabuf_head(resp);
 367         }
 368     } else if (ctx->flags & CTX_FLAG_EAP_SUCCESS) {
 369         major = initReady(minor, ctx);
 370         if (GSS_ERROR(major))
 371             goto cleanup;
 372
 373         ctx->flags &= ~(CTX_FLAG_EAP_SUCCESS);
 374         major = GSS_S_CONTINUE_NEEDED;
 375         ctx->state = EAP_STATE_GSS_CHANNEL_BINDINGS;
 376     } else if ((ctx->flags & CTX_FLAG_EAP_FAIL) || code == 0) {
 377         major = GSS_S_FAILURE;
 378     }
 379
 380 cleanup:
 381     if (respBuf.value != NULL) {
 382         OM_uint32 tmpMajor;
 383
 384         assert(major == GSS_S_CONTINUE_NEEDED);
 385
 386         tmpMajor = duplicateBuffer(&tmpMinor, &respBuf, outputToken);
 387         if (GSS_ERROR(tmpMajor)) {
 388             major = tmpMajor;
 389             *minor = tmpMinor;
 390         }
 391     }
 392
 393     wpabuf_set(&ctx->initiatorCtx.reqData, NULL, 0);
 394     peerConfigFree(&tmpMinor, ctx);
 395
 396     return major;
 397 }
 398
 399 #if 0
 400 static OM_uint32
 401 eapGssSmInitKeyTransport(OM_uint32 *minor,
 402                          gss_cred_id_t cred,
 403                          gss_ctx_id_t ctx,
 404                          gss_name_t target,
 405                          gss_OID mech,
 406                          OM_uint32 reqFlags,
 407                          OM_uint32 timeReq,
 408                          gss_channel_bindings_t chanBindings,
 409                          gss_buffer_t inputToken,
 410                          gss_buffer_t outputToken)
 411 {
 412     GSSEAP_NOT_IMPLEMENTED;
 413 }
 414
 415 static OM_uint32
 416 eapGssSmInitSecureAssoc(OM_uint32 *minor,
 417                         gss_cred_id_t cred,
 418                         gss_ctx_id_t ctx,
 419                         gss_name_t target,
 420                         gss_OID mech,
 421                         OM_uint32 reqFlags,
 422                         OM_uint32 timeReq,
 423                         gss_channel_bindings_t chanBindings,
 424                         gss_buffer_t inputToken,
 425                         gss_buffer_t outputToken)
 426 {
 427     GSSEAP_NOT_IMPLEMENTED;
 428 }
 429 #endif
 430
 431 static OM_uint32
 432 eapGssSmInitGssChannelBindings(OM_uint32 *minor,
 433                                gss_cred_id_t cred,
 434                                gss_ctx_id_t ctx,
 435                                gss_name_t target,
 436                                gss_OID mech,
 437                                OM_uint32 reqFlags,
 438                                OM_uint32 timeReq,
 439                                gss_channel_bindings_t chanBindings,
 440                                gss_buffer_t inputToken,
 441                                gss_buffer_t outputToken)
 442 {
 443     OM_uint32 major, tmpMinor;
 444     gss_iov_buffer_desc iov[2];
 445     gss_buffer_desc buf;
 446
 447     iov[0].type = GSS_IOV_BUFFER_TYPE_DATA;
 448     iov[0].buffer.length = 0;
 449     iov[0].buffer.value = NULL;
 450
 451     iov[1].type = GSS_IOV_BUFFER_TYPE_HEADER | GSS_IOV_BUFFER_FLAG_ALLOCATE;
 452     iov[1].buffer.length = 0;
 453     iov[1].buffer.value = NULL;
 454
 455     if (chanBindings != GSS_C_NO_CHANNEL_BINDINGS)
 456         iov[0].buffer = chanBindings->application_data;
 457
 458     major = gssEapWrapOrGetMIC(minor, ctx, FALSE, FALSE, iov, 2,
 459                                TOK_TYPE_GSS_CB);
 460     if (GSS_ERROR(major))
 461         goto cleanup;
 462
 463     /* Skip past token ID */
 464     assert(iov[1].buffer.length > 2);
 465     assert(load_uint16_be(iov[1].buffer.value) == TOK_TYPE_GSS_CB);
 466
 467     buf.length = iov[1].buffer.length - 2;
 468     buf.value = (unsigned char *)iov[1].buffer.value + 2;
 469
 470     major = duplicateBuffer(minor, &buf, outputToken);
 471     if (GSS_ERROR(major))
 472         goto cleanup;
 473
 474     major = GSS_S_COMPLETE;
 475     ctx->state = EAP_STATE_ESTABLISHED;
 476
 477 cleanup:
 478     gssEapReleaseIov(iov, 2);
 479
 480     return major;
 481 }
 482
 483 static OM_uint32
 484 eapGssSmInitEstablished(OM_uint32 *minor,
 485                         gss_cred_id_t cred,
 486                         gss_ctx_id_t ctx,
 487                         gss_name_t target,
 488                         gss_OID mech,
 489                         OM_uint32 reqFlags,
 490                         OM_uint32 timeReq,
 491                         gss_channel_bindings_t chanBindings,
 492                         gss_buffer_t inputToken,
 493                         gss_buffer_t outputToken)
 494 {
 495     /* Called with already established context */
 496     *minor = EINVAL;
 497     return GSS_S_BAD_STATUS;
 498 }
 499
 500 static struct eap_gss_initiator_sm {
 501     enum gss_eap_token_type inputTokenType;
 502     enum gss_eap_token_type outputTokenType;
 503     OM_uint32 (*processToken)(OM_uint32 *,
 504                               gss_cred_id_t,
 505                               gss_ctx_id_t,
 506                               gss_name_t,
 507                               gss_OID,
 508                               OM_uint32,
 509                               OM_uint32,
 510                               gss_channel_bindings_t,
 511                               gss_buffer_t,
 512                               gss_buffer_t);
 513 } eapGssInitiatorSm[] = {
 514     { TOK_TYPE_EAP_REQ, TOK_TYPE_EAP_RESP,  eapGssSmInitAuthenticate        },
 515 #if 0
 516     { TOK_TYPE_EAP_REQ, TOK_TYPE_EAP_RESP,  eapGssSmInitKeyTransport        },
 517     { TOK_TYPE_EAP_REQ, TOK_TYPE_EAP_RESP,  eapGssSmInitSecureAssoc         },
 518 #endif
 519     { TOK_TYPE_NONE,    TOK_TYPE_GSS_CB,    eapGssSmInitGssChannelBindings  },
 520     { TOK_TYPE_NONE,    TOK_TYPE_NONE,      eapGssSmInitEstablished         },
 521 };
 522
 523 OM_uint32
 524 gss_init_sec_context(OM_uint32 *minor,
 525                      gss_cred_id_t cred,
 526                      gss_ctx_id_t *context_handle,
 527                      gss_name_t target_name,
 528                      gss_OID mech_type,
 529                      OM_uint32 req_flags,
 530                      OM_uint32 time_req,
 531                      gss_channel_bindings_t input_chan_bindings,
 532                      gss_buffer_t input_token,
 533                      gss_OID *actual_mech_type,
 534                      gss_buffer_t output_token,
 535                      OM_uint32 *ret_flags,
 536                      OM_uint32 *time_rec)
 537 {
 538     OM_uint32 major;
 539     OM_uint32 tmpMajor, tmpMinor;
 540     gss_ctx_id_t ctx = *context_handle;
 541     struct eap_gss_initiator_sm *sm = NULL;
 542     gss_buffer_desc innerInputToken, innerOutputToken;
 543
 544     *minor = 0;
 545
 546     innerOutputToken.length = 0;
 547     innerOutputToken.value = NULL;
 548
 549     output_token->length = 0;
 550     output_token->value = NULL;
 551
 552     if (cred != GSS_C_NO_CREDENTIAL && !(cred->flags & CRED_FLAG_INITIATE)) {
 553         return GSS_S_NO_CRED;
 554     }
 555
 556     if (ctx == GSS_C_NO_CONTEXT) {
 557         if (input_token != GSS_C_NO_BUFFER && input_token->length != 0) {
 558             return GSS_S_DEFECTIVE_TOKEN;
 559         }
 560
 561         major = gssEapAllocContext(minor, &ctx);
 562         if (GSS_ERROR(major))
 563             return major;
 564
 565         ctx->flags |= CTX_FLAG_INITIATOR;
 566
 567         *context_handle = ctx;
 568     }
 569
 570     GSSEAP_MUTEX_LOCK(&ctx->mutex);
 571
 572     sm = &eapGssInitiatorSm[ctx->state];
 573
 574     if (input_token != GSS_C_NO_BUFFER) {
 575         major = gssEapVerifyToken(minor, ctx, input_token,
 576                                   sm->inputTokenType, &innerInputToken);
 577         if (GSS_ERROR(major))
 578             goto cleanup;
 579     } else {
 580         innerInputToken.length = 0;
 581         innerInputToken.value = NULL;
 582     }
 583
 584     /*
 585      * Advance through state machine whilst empty tokens are emitted and
 586      * the status is not GSS_S_COMPLETE or an error status.
 587      */
 588     do {
 589         sm = &eapGssInitiatorSm[ctx->state];
 590
 591         major = (sm->processToken)(minor,
 592                                    cred,
 593                                    ctx,
 594                                    target_name,
 595                                    mech_type,
 596                                    req_flags,
 597                                    time_req,
 598                                    input_chan_bindings,
 599                                    &innerInputToken,
 600                                    &innerOutputToken);
 601         if (GSS_ERROR(major))
 602             goto cleanup;
 603     } while (major == GSS_S_CONTINUE_NEEDED && innerOutputToken.value == NULL);
 604
 605     if (actual_mech_type != NULL) {
 606         if (!gssEapInternalizeOid(ctx->mechanismUsed, actual_mech_type))
 607             duplicateOid(&tmpMinor, ctx->mechanismUsed, actual_mech_type);
 608     }
 609     if (innerOutputToken.value != NULL) {
 610         tmpMajor = gssEapMakeToken(&tmpMinor, ctx, &innerOutputToken,
 611                                    sm->outputTokenType, output_token);
 612         if (GSS_ERROR(tmpMajor)) {
 613             major = tmpMajor;
 614             *minor = tmpMinor;
 615             goto cleanup;
 616         }
 617     }
 618     if (ret_flags != NULL)
 619         *ret_flags = ctx->gssFlags;
 620     if (time_rec != NULL)
 621         gss_context_time(&tmpMinor, ctx, time_rec);
 622
 623     assert(ctx->state == EAP_STATE_ESTABLISHED || major == GSS_S_CONTINUE_NEEDED);
 624
 625 cleanup:
 626     GSSEAP_MUTEX_UNLOCK(&ctx->mutex);
 627
 628     if (GSS_ERROR(major))
 629         gssEapReleaseContext(&tmpMinor, context_handle);
 630
 631     gss_release_buffer(&tmpMinor, &innerOutputToken);
 632
 633     return major;
 634 }