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
  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 completeInit(OM_uint32 *minor,
 237              gss_ctx_id_t ctx)
 238 {
 239     OM_uint32 major;
 240     const unsigned char *key;
 241     size_t keyLength;
 242     krb5_context krbContext;
 243
 244     GSSEAP_KRB_INIT(&krbContext);
 245
 246     /* Cache encryption type derived from selected mechanism OID */
 247     major = gssEapOidToEnctype(minor, ctx->mechanismUsed, &ctx->encryptionType);
 248     if (GSS_ERROR(major))
 249         return major;
 250
 251     if (ctx->encryptionType != ENCTYPE_NULL &&
 252         eap_key_available(ctx->initiatorCtx.eap)) {
 253         key = eap_get_eapKeyData(ctx->initiatorCtx.eap, &keyLength);
 254
 255         major = gssEapDeriveRFC3961Key(minor, key, keyLength,
 256                                        ctx->encryptionType, &ctx->rfc3961Key);
 257         if (GSS_ERROR(major))
 258             return major;
 259     } else {
 260         /*
 261          * draft-howlett-eap-gss says that integrity/confidentialty should
 262          * always be advertised as available, but if we have no keying
 263          * material it seems confusing to the caller to advertise this.
 264          */
 265         ctx->gssFlags &= ~(GSS_C_INTEG_FLAG | GSS_C_CONF_FLAG);
 266     }
 267
 268     sequenceInit(&ctx->seqState, ctx->recvSeq,
 269                  ((ctx->gssFlags & GSS_C_REPLAY_FLAG) != 0),
 270                  ((ctx->gssFlags & GSS_C_SEQUENCE_FLAG) != 0),
 271                  TRUE);
 272
 273     return GSS_S_COMPLETE;
 274 }
 275
 276 static OM_uint32
 277 eapGssSmInitAuthenticate(OM_uint32 *minor,
 278                          gss_cred_id_t cred,
 279                          gss_ctx_id_t ctx,
 280                          gss_name_t target,
 281                          gss_OID mech,
 282                          OM_uint32 reqFlags,
 283                          OM_uint32 timeReq,
 284                          gss_channel_bindings_t chanBindings,
 285                          gss_buffer_t inputToken,
 286                          gss_buffer_t outputToken)
 287 {
 288     OM_uint32 major;
 289     OM_uint32 tmpMajor, tmpMinor;
 290     time_t now;
 291     int initialContextToken = 0, code;
 292     struct wpabuf *resp = NULL;
 293
 294     initialContextToken = (inputToken == GSS_C_NO_BUFFER ||
 295                            inputToken->length == 0);
 296
 297     major = peerConfigInit(minor, cred, ctx, initialContextToken);
 298     if (GSS_ERROR(major))
 299         goto cleanup;
 300
 301     if (initialContextToken) {
 302         struct eap_config eapConfig;
 303
 304         memset(&eapConfig, 0, sizeof(eapConfig));
 305         ctx->flags |= CTX_FLAG_EAP_PORT_ENABLED;
 306
 307         ctx->initiatorCtx.eap = eap_peer_sm_init(ctx,
 308                                                  &gssEapPolicyCallbacks,
 309                                                  ctx,
 310                                                  &eapConfig);
 311
 312         time(&now);
 313         if (timeReq == 0 || timeReq == GSS_C_INDEFINITE)
 314             ctx->expiryTime = 0;
 315         else
 316             ctx->expiryTime = now + timeReq;
 317
 318         major = gss_duplicate_name(minor, cred->name, &ctx->initiatorName);
 319         if (GSS_ERROR(major))
 320             goto cleanup;
 321
 322         major = gss_duplicate_name(minor, target, &ctx->acceptorName);
 323         if (GSS_ERROR(major))
 324             goto cleanup;
 325
 326         if (mech == GSS_C_NULL_OID || oidEqual(mech, GSS_EAP_MECHANISM)) {
 327             major = gssEapDefaultMech(minor, &ctx->mechanismUsed);
 328         } else if (gssEapIsConcreteMechanismOid(mech)) {
 329             if (!gssEapInternalizeOid(mech, &ctx->mechanismUsed))
 330                 major = duplicateOid(minor, mech, &ctx->mechanismUsed);
 331         } else {
 332             major = GSS_S_BAD_MECH;
 333         }
 334         if (GSS_ERROR(major))
 335             goto cleanup;
 336
 337         resp = eap_sm_buildIdentity(ctx->initiatorCtx.eap, 0, 1);
 338         major = GSS_S_CONTINUE_NEEDED;
 339         goto cleanup;
 340     } else {
 341         ctx->flags |= CTX_FLAG_EAP_REQ; /* we have a Request from the acceptor */
 342     }
 343
 344     wpabuf_set(&ctx->initiatorCtx.reqData,
 345                inputToken->value, inputToken->length);
 346
 347     major = GSS_S_CONTINUE_NEEDED;
 348
 349     code = eap_peer_sm_step(ctx->initiatorCtx.eap);
 350     if (ctx->flags & CTX_FLAG_EAP_RESP) {
 351         ctx->flags &= ~(CTX_FLAG_EAP_RESP);
 352
 353         resp = eap_get_eapRespData(ctx->initiatorCtx.eap);
 354     } else if (ctx->flags & CTX_FLAG_EAP_SUCCESS) {
 355         major = completeInit(minor, ctx);
 356         ctx->flags &= ~(CTX_FLAG_EAP_SUCCESS);
 357         ctx->state = EAP_STATE_ESTABLISHED;
 358     } else if ((ctx->flags & CTX_FLAG_EAP_FAIL) || code == 0) {
 359         major = GSS_S_FAILURE;
 360     }
 361
 362 cleanup:
 363     if (resp != NULL) {
 364         OM_uint32 tmpMajor;
 365         gss_buffer_desc buf;
 366
 367         assert(major == GSS_S_CONTINUE_NEEDED);
 368
 369         buf.length = wpabuf_len(resp);
 370         buf.value = (void *)wpabuf_head(resp);
 371
 372         tmpMajor = duplicateBuffer(&tmpMinor, &buf, outputToken);
 373         if (GSS_ERROR(tmpMajor)) {
 374             major = tmpMajor;
 375             *minor = tmpMinor;
 376         }
 377     }
 378
 379     wpabuf_set(&ctx->initiatorCtx.reqData, NULL, 0);
 380     peerConfigFree(&tmpMinor, ctx);
 381
 382     return major;
 383 }
 384
 385 static OM_uint32
 386 eapGssSmInitKeyTransport(OM_uint32 *minor,
 387                          gss_cred_id_t cred,
 388                          gss_ctx_id_t ctx,
 389                          gss_name_t target,
 390                          gss_OID mech,
 391                          OM_uint32 reqFlags,
 392                          OM_uint32 timeReq,
 393                          gss_channel_bindings_t chanBindings,
 394                          gss_buffer_t inputToken,
 395                          gss_buffer_t outputToken)
 396 {
 397     GSSEAP_NOT_IMPLEMENTED;
 398 }
 399
 400 static OM_uint32
 401 eapGssSmInitSecureAssoc(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 eapGssSmInitGssChannelBindings(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
 430 static OM_uint32
 431 eapGssSmInitEstablished(OM_uint32 *minor,
 432                         gss_cred_id_t cred,
 433                         gss_ctx_id_t ctx,
 434                         gss_name_t target,
 435                         gss_OID mech,
 436                         OM_uint32 reqFlags,
 437                         OM_uint32 timeReq,
 438                         gss_channel_bindings_t chanBindings,
 439                         gss_buffer_t inputToken,
 440                         gss_buffer_t outputToken)
 441 {
 442     /* Called with already established context */
 443     *minor = EINVAL;
 444     return GSS_S_BAD_STATUS;
 445 }
 446
 447 static struct eap_gss_initiator_sm {
 448     enum gss_eap_token_type inputTokenType;
 449     enum gss_eap_token_type outputTokenType;
 450     OM_uint32 (*processToken)(OM_uint32 *,
 451                               gss_cred_id_t,
 452                               gss_ctx_id_t,
 453                               gss_name_t,
 454                               gss_OID,
 455                               OM_uint32,
 456                               OM_uint32,
 457                               gss_channel_bindings_t,
 458                               gss_buffer_t,
 459                               gss_buffer_t);
 460 } eapGssInitiatorSm[] = {
 461     { TOK_TYPE_EAP_REQ, TOK_TYPE_EAP_RESP,  eapGssSmInitAuthenticate        },
 462     { TOK_TYPE_EAP_REQ, TOK_TYPE_EAP_RESP,  eapGssSmInitKeyTransport        },
 463     { TOK_TYPE_EAP_REQ, TOK_TYPE_EAP_RESP,  eapGssSmInitSecureAssoc         },
 464     { TOK_TYPE_GSS_CB,  TOK_TYPE_NONE,      eapGssSmInitGssChannelBindings  },
 465     { TOK_TYPE_NONE,    TOK_TYPE_NONE,      eapGssSmInitEstablished         },
 466 };
 467
 468 OM_uint32
 469 gss_init_sec_context(OM_uint32 *minor,
 470                      gss_cred_id_t cred,
 471                      gss_ctx_id_t *context_handle,
 472                      gss_name_t target_name,
 473                      gss_OID mech_type,
 474                      OM_uint32 req_flags,
 475                      OM_uint32 time_req,
 476                      gss_channel_bindings_t input_chan_bindings,
 477                      gss_buffer_t input_token,
 478                      gss_OID *actual_mech_type,
 479                      gss_buffer_t output_token,
 480                      OM_uint32 *ret_flags,
 481                      OM_uint32 *time_rec)
 482 {
 483     OM_uint32 major;
 484     OM_uint32 tmpMajor, tmpMinor;
 485     gss_ctx_id_t ctx = *context_handle;
 486     struct eap_gss_initiator_sm *sm = NULL;
 487     gss_buffer_desc innerInputToken, innerOutputToken;
 488
 489     *minor = 0;
 490
 491     innerOutputToken.length = 0;
 492     innerOutputToken.value = NULL;
 493
 494     output_token->length = 0;
 495     output_token->value = NULL;
 496
 497     if (cred != GSS_C_NO_CREDENTIAL && !(cred->flags & CRED_FLAG_INITIATE)) {
 498         return GSS_S_NO_CRED;
 499     }
 500
 501     if (ctx == GSS_C_NO_CONTEXT) {
 502         if (input_token != GSS_C_NO_BUFFER && input_token->length != 0) {
 503             return GSS_S_DEFECTIVE_TOKEN;
 504         }
 505
 506         major = gssEapAllocContext(minor, &ctx);
 507         if (GSS_ERROR(major))
 508             return major;
 509
 510         ctx->flags |= CTX_FLAG_INITIATOR;
 511
 512         *context_handle = ctx;
 513     }
 514
 515     GSSEAP_MUTEX_LOCK(&ctx->mutex);
 516
 517     sm = &eapGssInitiatorSm[ctx->state];
 518
 519     if (input_token != GSS_C_NO_BUFFER) {
 520         major = gssEapVerifyToken(minor, ctx, input_token,
 521                                   sm->inputTokenType, &innerInputToken);
 522         if (GSS_ERROR(major))
 523             goto cleanup;
 524     } else {
 525         innerInputToken.length = 0;
 526         innerInputToken.value = NULL;
 527     }
 528
 529     /*
 530      * Advance through state machine whilst empty tokens are emitted and
 531      * the status is not GSS_S_COMPLETE or an error status.
 532      */
 533     do {
 534         major = (sm->processToken)(minor,
 535                                    cred,
 536                                    ctx,
 537                                    target_name,
 538                                    mech_type,
 539                                    req_flags,
 540                                    time_req,
 541                                    input_chan_bindings,
 542                                    &innerInputToken,
 543                                    &innerOutputToken);
 544         if (GSS_ERROR(major))
 545             goto cleanup;
 546     } while (major == GSS_S_CONTINUE_NEEDED && innerOutputToken.length == 0);
 547
 548     if (actual_mech_type != NULL) {
 549         if (!gssEapInternalizeOid(ctx->mechanismUsed, actual_mech_type))
 550             duplicateOid(&tmpMinor, ctx->mechanismUsed, actual_mech_type);
 551     }
 552     if (innerOutputToken.length != 0) {
 553         tmpMajor = gssEapMakeToken(&tmpMinor, ctx, &innerOutputToken,
 554                                    sm->outputTokenType, output_token);
 555         if (GSS_ERROR(tmpMajor)) {
 556             major = tmpMajor;
 557             *minor = tmpMinor;
 558             goto cleanup;
 559         }
 560     }
 561     if (ret_flags != NULL)
 562         *ret_flags = ctx->gssFlags;
 563     if (time_rec != NULL)
 564         gss_context_time(&tmpMinor, ctx, time_rec);
 565
 566     assert(ctx->state == EAP_STATE_ESTABLISHED || major == GSS_S_CONTINUE_NEEDED);
 567
 568 cleanup:
 569     GSSEAP_MUTEX_UNLOCK(&ctx->mutex);
 570
 571     if (GSS_ERROR(major))
 572         gssEapReleaseContext(&tmpMinor, context_handle);
 573
 574     gss_release_buffer(&tmpMinor, &innerOutputToken);
 575
 576     return major;
 577 }