mech_eap/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 static struct eap_peer_config *
  74 peerGetConfig(void *ctx)
  75 {
  76     gss_ctx_id_t gssCtx = (gss_ctx_id_t)ctx;
  77
  78     return &gssCtx->initiatorCtx.eapPeerConfig;
  79 }
  80
  81 static Boolean
  82 peerGetBool(void *data, enum eapol_bool_var variable)
  83 {
  84     gss_ctx_id_t ctx = data;
  85     OM_uint32 flag;
  86
  87     if (ctx == GSS_C_NO_CONTEXT)
  88         return FALSE;
  89
  90     flag = policyVariableToFlag(variable);
  91
  92     return ((ctx->flags & flag) != 0);
  93 }
  94
  95 static void
  96 peerSetBool(void *data, enum eapol_bool_var variable,
  97             Boolean value)
  98 {
  99     gss_ctx_id_t ctx = data;
 100     OM_uint32 flag;
 101
 102     if (ctx == GSS_C_NO_CONTEXT)
 103         return;
 104
 105     flag = policyVariableToFlag(variable);
 106
 107     if (value)
 108         ctx->flags |= flag;
 109     else
 110         ctx->flags &= ~(flag);
 111 }
 112
 113 static unsigned int
 114 peerGetInt(void *data, enum eapol_int_var variable)
 115 {
 116     gss_ctx_id_t ctx = data;
 117
 118     if (ctx == GSS_C_NO_CONTEXT)
 119         return FALSE;
 120
 121     assert(CTX_IS_INITIATOR(ctx));
 122
 123     switch (variable) {
 124     case EAPOL_idleWhile:
 125         return ctx->initiatorCtx.idleWhile;
 126         break;
 127     }
 128
 129     return 0;
 130 }
 131
 132 static void
 133 peerSetInt(void *data, enum eapol_int_var variable,
 134            unsigned int value)
 135 {
 136     gss_ctx_id_t ctx = data;
 137
 138     if (ctx == GSS_C_NO_CONTEXT)
 139         return;
 140
 141     assert(CTX_IS_INITIATOR(ctx));
 142
 143     switch (variable) {
 144     case EAPOL_idleWhile:
 145         ctx->initiatorCtx.idleWhile = value;
 146         break;
 147     }
 148 }
 149
 150 static struct wpabuf *
 151 peerGetEapReqData(void *ctx)
 152 {
 153     gss_ctx_id_t gssCtx = (gss_ctx_id_t)ctx;
 154
 155     return &gssCtx->initiatorCtx.reqData;
 156 }
 157
 158 static void
 159 peerSetConfigBlob(void *ctx, struct wpa_config_blob *blob)
 160 {
 161 }
 162
 163 static const struct wpa_config_blob *
 164 peerGetConfigBlob(void *ctx, const char *name)
 165 {
 166     return NULL;
 167 }
 168
 169 static void
 170 peerNotifyPending(void *ctx)
 171 {
 172 }
 173
 174 static struct eapol_callbacks gssEapPolicyCallbacks = {
 175     peerGetConfig,
 176     peerGetBool,
 177     peerSetBool,
 178     peerGetInt,
 179     peerSetInt,
 180     peerGetEapReqData,
 181     peerSetConfigBlob,
 182     peerGetConfigBlob,
 183     peerNotifyPending,
 184 };
 185
 186 extern int wpa_debug_level;
 187
 188 static OM_uint32
 189 peerConfigInit(OM_uint32 *minor,
 190                gss_cred_id_t cred,
 191                gss_ctx_id_t ctx)
 192 {
 193     krb5_context krbContext;
 194     struct eap_peer_config *eapPeerConfig = &ctx->initiatorCtx.eapPeerConfig;
 195     krb5_error_code code;
 196     char *identity;
 197
 198     GSSEAP_KRB_INIT(&krbContext);
 199
 200     eapPeerConfig->fragment_size = 1024;
 201     wpa_debug_level = 0;
 202
 203     code = krb5_unparse_name(krbContext, cred->name->krbPrincipal, &identity);
 204     if (code != 0) {
 205         *minor = code;
 206         return GSS_S_FAILURE;
 207     }
 208
 209     eapPeerConfig->identity = (unsigned char *)identity;
 210     eapPeerConfig->identity_len = strlen(identity);
 211     eapPeerConfig->password = (unsigned char *)cred->password.value;
 212     eapPeerConfig->password_len = cred->password.length;
 213
 214     return GSS_S_COMPLETE;
 215 }
 216
 217 static OM_uint32
 218 peerConfigFree(OM_uint32 *minor,
 219                gss_ctx_id_t ctx)
 220 {
 221     krb5_context krbContext;
 222     struct eap_peer_config *eapPeerConfig = &ctx->initiatorCtx.eapPeerConfig;
 223
 224     GSSEAP_KRB_INIT(&krbContext);
 225
 226     krb5_free_unparsed_name(krbContext, (char *)eapPeerConfig->identity);
 227
 228     return GSS_S_COMPLETE;
 229 }
 230
 231 static OM_uint32
 232 initReady(OM_uint32 *minor, gss_ctx_id_t ctx)
 233 {
 234     OM_uint32 major;
 235     const unsigned char *key;
 236     size_t keyLength;
 237
 238     /* Cache encryption type derived from selected mechanism OID */
 239     major = gssEapOidToEnctype(minor, ctx->mechanismUsed, &ctx->encryptionType);
 240     if (GSS_ERROR(major))
 241         return major;
 242
 243     if (ctx->encryptionType != ENCTYPE_NULL &&
 244         eap_key_available(ctx->initiatorCtx.eap)) {
 245         key = eap_get_eapKeyData(ctx->initiatorCtx.eap, &keyLength);
 246
 247         major = gssEapDeriveRfc3961Key(minor, key, keyLength,
 248                                        ctx->encryptionType, &ctx->rfc3961Key);
 249         if (GSS_ERROR(major))
 250             return major;
 251
 252         major = rfc3961ChecksumTypeForKey(minor, &ctx->rfc3961Key,
 253                                            &ctx->checksumType);
 254         if (GSS_ERROR(major))
 255             return major;
 256     } else {
 257         /*
 258          * draft-howlett-eap-gss says that integrity/confidentialty should
 259          * always be advertised as available, but if we have no keying
 260          * material it seems confusing to the caller to advertise this.
 261          */
 262         ctx->gssFlags &= ~(GSS_C_INTEG_FLAG | GSS_C_CONF_FLAG);
 263     }
 264
 265     major = sequenceInit(minor,
 266                          &ctx->seqState,
 267                          ctx->recvSeq,
 268                          ((ctx->gssFlags & GSS_C_REPLAY_FLAG) != 0),
 269                          ((ctx->gssFlags & GSS_C_SEQUENCE_FLAG) != 0),
 270                          TRUE);
 271     if (GSS_ERROR(major))
 272         return major;
 273
 274     return GSS_S_COMPLETE;
 275 }
 276
 277 static OM_uint32
 278 eapGssSmInitIdentity(OM_uint32 *minor,
 279                      gss_cred_id_t cred,
 280                      gss_ctx_id_t ctx,
 281                      gss_name_t target,
 282                      gss_OID mech,
 283                      OM_uint32 reqFlags,
 284                      OM_uint32 timeReq,
 285                      gss_channel_bindings_t chanBindings,
 286                      gss_buffer_t inputToken,
 287                      gss_buffer_t outputToken)
 288 {
 289     time_t now;
 290     OM_uint32 major;
 291     int initialContextToken;
 292
 293     initialContextToken = (inputToken == GSS_C_NO_BUFFER ||
 294                            inputToken->length == 0);
 295     if (!initialContextToken)
 296         return GSS_S_DEFECTIVE_TOKEN;
 297
 298     time(&now);
 299     if (timeReq == 0 || timeReq == GSS_C_INDEFINITE)
 300         ctx->expiryTime = 0;
 301     else
 302         ctx->expiryTime = now + timeReq;
 303
 304     major = gss_duplicate_name(minor, cred->name, &ctx->initiatorName);
 305     if (GSS_ERROR(major))
 306         return major;
 307
 308     major = gss_duplicate_name(minor, target, &ctx->acceptorName);
 309     if (GSS_ERROR(major))
 310         return major;
 311
 312     if (mech == GSS_C_NULL_OID || oidEqual(mech, GSS_EAP_MECHANISM)) {
 313         major = gssEapDefaultMech(minor, &ctx->mechanismUsed);
 314     } else if (gssEapIsConcreteMechanismOid(mech)) {
 315         if (!gssEapInternalizeOid(mech, &ctx->mechanismUsed))
 316             major = duplicateOid(minor, mech, &ctx->mechanismUsed);
 317     } else {
 318         major = GSS_S_BAD_MECH;
 319     }
 320     if (GSS_ERROR(major))
 321         return major;
 322
 323     /* If credentials were provided, check they're usable with this mech */
 324     if (!gssEapCredAvailable(cred, ctx->mechanismUsed))
 325         return GSS_S_BAD_MECH;
 326
 327     ctx->state = EAP_STATE_AUTHENTICATE;
 328
 329     return GSS_S_CONTINUE_NEEDED;
 330 }
 331
 332 static struct wpabuf emptyWpaBuffer;
 333
 334 static OM_uint32
 335 eapGssSmInitAuthenticate(OM_uint32 *minor,
 336                          gss_cred_id_t cred,
 337                          gss_ctx_id_t ctx,
 338                          gss_name_t target,
 339                          gss_OID mech,
 340                          OM_uint32 reqFlags,
 341                          OM_uint32 timeReq,
 342                          gss_channel_bindings_t chanBindings,
 343                          gss_buffer_t inputToken,
 344                          gss_buffer_t outputToken)
 345 {
 346     OM_uint32 major;
 347     OM_uint32 tmpMinor;
 348     int code;
 349     struct wpabuf *resp = NULL;
 350     int initialContextToken;
 351
 352     initialContextToken = (inputToken == GSS_C_NO_BUFFER ||
 353                            inputToken->length == 0);
 354
 355     major = peerConfigInit(minor, cred, ctx);
 356     if (GSS_ERROR(major))
 357         goto cleanup;
 358
 359     if (ctx->initiatorCtx.eap == NULL) {
 360         struct eap_config eapConfig;
 361
 362         memset(&eapConfig, 0, sizeof(eapConfig));
 363
 364         ctx->initiatorCtx.eap = eap_peer_sm_init(ctx,
 365                                                  &gssEapPolicyCallbacks,
 366                                                  ctx,
 367                                                  &eapConfig);
 368         if (ctx->initiatorCtx.eap == NULL) {
 369             major = GSS_S_FAILURE;
 370             goto cleanup;
 371         }
 372
 373         ctx->flags |= CTX_FLAG_EAP_RESTART | CTX_FLAG_EAP_PORT_ENABLED;
 374     }
 375
 376     ctx->flags |= CTX_FLAG_EAP_REQ; /* we have a Request from the acceptor */
 377
 378     wpabuf_set(&ctx->initiatorCtx.reqData,
 379                inputToken->value, inputToken->length);
 380
 381     major = GSS_S_CONTINUE_NEEDED;
 382
 383     code = eap_peer_sm_step(ctx->initiatorCtx.eap);
 384     if (ctx->flags & CTX_FLAG_EAP_RESP) {
 385         ctx->flags &= ~(CTX_FLAG_EAP_RESP);
 386
 387         resp = eap_get_eapRespData(ctx->initiatorCtx.eap);
 388     } else if (ctx->flags & CTX_FLAG_EAP_SUCCESS) {
 389         major = initReady(minor, ctx);
 390         if (GSS_ERROR(major))
 391             goto cleanup;
 392
 393         ctx->flags &= ~(CTX_FLAG_EAP_SUCCESS);
 394         major = GSS_S_CONTINUE_NEEDED;
 395         ctx->state = EAP_STATE_GSS_CHANNEL_BINDINGS;
 396     } else if (ctx->flags & CTX_FLAG_EAP_FAIL) {
 397         major = GSS_S_DEFECTIVE_CREDENTIAL;
 398     } else if (code == 0 && initialContextToken) {
 399         resp = &emptyWpaBuffer;
 400         major = GSS_S_CONTINUE_NEEDED;
 401     } else {
 402         major = GSS_S_FAILURE;
 403     }
 404
 405 cleanup:
 406     if (resp != NULL) {
 407         OM_uint32 tmpMajor;
 408         gss_buffer_desc respBuf;
 409
 410         assert(major == GSS_S_CONTINUE_NEEDED);
 411
 412         respBuf.length = wpabuf_len(resp);
 413         respBuf.value = (void *)wpabuf_head(resp);
 414
 415         tmpMajor = duplicateBuffer(&tmpMinor, &respBuf, outputToken);
 416         if (GSS_ERROR(tmpMajor)) {
 417             major = tmpMajor;
 418             *minor = tmpMinor;
 419         }
 420     }
 421
 422     wpabuf_set(&ctx->initiatorCtx.reqData, NULL, 0);
 423     peerConfigFree(&tmpMinor, ctx);
 424
 425     return major;
 426 }
 427
 428 static OM_uint32
 429 eapGssSmInitGssChannelBindings(OM_uint32 *minor,
 430                                gss_cred_id_t cred,
 431                                gss_ctx_id_t ctx,
 432                                gss_name_t target,
 433                                gss_OID mech,
 434                                OM_uint32 reqFlags,
 435                                OM_uint32 timeReq,
 436                                gss_channel_bindings_t chanBindings,
 437                                gss_buffer_t inputToken,
 438                                gss_buffer_t outputToken)
 439 {
 440     OM_uint32 major;
 441     gss_iov_buffer_desc iov[2];
 442     gss_buffer_desc buf;
 443
 444     iov[0].type = GSS_IOV_BUFFER_TYPE_DATA;
 445     iov[0].buffer.length = 0;
 446     iov[0].buffer.value = NULL;
 447
 448     iov[1].type = GSS_IOV_BUFFER_TYPE_HEADER | GSS_IOV_BUFFER_FLAG_ALLOCATE;
 449     iov[1].buffer.length = 0;
 450     iov[1].buffer.value = NULL;
 451
 452     if (chanBindings != GSS_C_NO_CHANNEL_BINDINGS)
 453         iov[0].buffer = chanBindings->application_data;
 454
 455     major = gssEapWrapOrGetMIC(minor, ctx, FALSE, FALSE, iov, 2,
 456                                TOK_TYPE_GSS_CB);
 457     if (GSS_ERROR(major))
 458         goto cleanup;
 459
 460     /* Skip past token ID */
 461     assert(iov[1].buffer.length > 2);
 462     assert(load_uint16_be(iov[1].buffer.value) == TOK_TYPE_GSS_CB);
 463
 464     buf.length = iov[1].buffer.length - 2;
 465     buf.value = (unsigned char *)iov[1].buffer.value + 2;
 466
 467     major = duplicateBuffer(minor, &buf, outputToken);
 468     if (GSS_ERROR(major))
 469         goto cleanup;
 470
 471     major = GSS_S_COMPLETE;
 472     ctx->state = EAP_STATE_ESTABLISHED;
 473
 474 cleanup:
 475     gssEapReleaseIov(iov, 2);
 476
 477     return major;
 478 }
 479
 480 static OM_uint32
 481 eapGssSmInitEstablished(OM_uint32 *minor,
 482                         gss_cred_id_t cred,
 483                         gss_ctx_id_t ctx,
 484                         gss_name_t target,
 485                         gss_OID mech,
 486                         OM_uint32 reqFlags,
 487                         OM_uint32 timeReq,
 488                         gss_channel_bindings_t chanBindings,
 489                         gss_buffer_t inputToken,
 490                         gss_buffer_t outputToken)
 491 {
 492     /* Called with already established context */
 493     *minor = EINVAL;
 494     return GSS_S_BAD_STATUS;
 495 }
 496
 497 static struct gss_eap_initiator_sm {
 498     enum gss_eap_token_type inputTokenType;
 499     enum gss_eap_token_type outputTokenType;
 500     OM_uint32 (*processToken)(OM_uint32 *,
 501                               gss_cred_id_t,
 502                               gss_ctx_id_t,
 503                               gss_name_t,
 504                               gss_OID,
 505                               OM_uint32,
 506                               OM_uint32,
 507                               gss_channel_bindings_t,
 508                               gss_buffer_t,
 509                               gss_buffer_t);
 510 } eapGssInitiatorSm[] = {
 511     { TOK_TYPE_NONE,    TOK_TYPE_EAP_RESP,  eapGssSmInitIdentity            },
 512     { TOK_TYPE_EAP_REQ, TOK_TYPE_EAP_RESP,  eapGssSmInitAuthenticate        },
 513     { TOK_TYPE_NONE,    TOK_TYPE_GSS_CB,    eapGssSmInitGssChannelBindings  },
 514     { TOK_TYPE_NONE,    TOK_TYPE_NONE,      eapGssSmInitEstablished         },
 515 };
 516
 517 OM_uint32
 518 gss_init_sec_context(OM_uint32 *minor,
 519                      gss_cred_id_t cred,
 520                      gss_ctx_id_t *context_handle,
 521                      gss_name_t target_name,
 522                      gss_OID mech_type,
 523                      OM_uint32 req_flags,
 524                      OM_uint32 time_req,
 525                      gss_channel_bindings_t input_chan_bindings,
 526                      gss_buffer_t input_token,
 527                      gss_OID *actual_mech_type,
 528                      gss_buffer_t output_token,
 529                      OM_uint32 *ret_flags,
 530                      OM_uint32 *time_rec)
 531 {
 532     OM_uint32 major;
 533     OM_uint32 tmpMajor, tmpMinor;
 534     gss_ctx_id_t ctx = *context_handle;
 535     struct gss_eap_initiator_sm *sm = NULL;
 536     gss_buffer_desc innerInputToken;
 537     gss_buffer_desc innerOutputToken = GSS_C_EMPTY_BUFFER;
 538
 539     *minor = 0;
 540
 541     output_token->length = 0;
 542     output_token->value = NULL;
 543
 544     if (cred != GSS_C_NO_CREDENTIAL && !(cred->flags & CRED_FLAG_INITIATE)) {
 545         return GSS_S_NO_CRED;
 546     }
 547
 548     if (ctx == GSS_C_NO_CONTEXT) {
 549         if (input_token != GSS_C_NO_BUFFER && input_token->length != 0) {
 550             return GSS_S_DEFECTIVE_TOKEN;
 551         }
 552
 553         major = gssEapAllocContext(minor, &ctx);
 554         if (GSS_ERROR(major))
 555             return major;
 556
 557         ctx->flags |= CTX_FLAG_INITIATOR;
 558
 559         *context_handle = ctx;
 560     }
 561
 562     GSSEAP_MUTEX_LOCK(&ctx->mutex);
 563
 564     sm = &eapGssInitiatorSm[ctx->state];
 565
 566     if (input_token != GSS_C_NO_BUFFER) {
 567         major = gssEapVerifyToken(minor, ctx, input_token,
 568                                   sm->inputTokenType, &innerInputToken);
 569         if (GSS_ERROR(major))
 570             goto cleanup;
 571     } else {
 572         innerInputToken.length = 0;
 573         innerInputToken.value = NULL;
 574     }
 575
 576     /*
 577      * Advance through state machine whilst empty tokens are emitted and
 578      * the status is not GSS_S_COMPLETE or an error status.
 579      */
 580     do {
 581         sm = &eapGssInitiatorSm[ctx->state];
 582
 583         major = (sm->processToken)(minor,
 584                                    cred,
 585                                    ctx,
 586                                    target_name,
 587                                    mech_type,
 588                                    req_flags,
 589                                    time_req,
 590                                    input_chan_bindings,
 591                                    &innerInputToken,
 592                                    &innerOutputToken);
 593         if (GSS_ERROR(major))
 594             goto cleanup;
 595     } while (major == GSS_S_CONTINUE_NEEDED && innerOutputToken.value == NULL);
 596
 597     if (actual_mech_type != NULL) {
 598         if (!gssEapInternalizeOid(ctx->mechanismUsed, actual_mech_type))
 599             duplicateOid(&tmpMinor, ctx->mechanismUsed, actual_mech_type);
 600     }
 601     if (innerOutputToken.value != NULL) {
 602         tmpMajor = gssEapMakeToken(&tmpMinor, ctx, &innerOutputToken,
 603                                    sm->outputTokenType, output_token);
 604         if (GSS_ERROR(tmpMajor)) {
 605             major = tmpMajor;
 606             *minor = tmpMinor;
 607             goto cleanup;
 608         }
 609     }
 610     if (ret_flags != NULL)
 611         *ret_flags = ctx->gssFlags;
 612     if (time_rec != NULL)
 613         gss_context_time(&tmpMinor, ctx, time_rec);
 614
 615     assert(ctx->state == EAP_STATE_ESTABLISHED || major == GSS_S_CONTINUE_NEEDED);
 616
 617 cleanup:
 618     GSSEAP_MUTEX_UNLOCK(&ctx->mutex);
 619
 620     if (GSS_ERROR(major))
 621         gssEapReleaseContext(&tmpMinor, context_handle);
 622
 623     gss_release_buffer(&tmpMinor, &innerOutputToken);
 624
 625     return major;
 626 }