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 /*
  36  * Mark a context as ready for cryptographic operations
  37  */
  38 static OM_uint32
  39 acceptReady(OM_uint32 *minor, gss_ctx_id_t ctx, gss_cred_id_t cred)
  40 {
  41     OM_uint32 major, tmpMinor;
  42     VALUE_PAIR *vp;
  43     gss_buffer_desc nameBuf = GSS_C_EMPTY_BUFFER;
  44
  45     /* Cache encryption type derived from selected mechanism OID */
  46     major = gssEapOidToEnctype(minor, ctx->mechanismUsed,
  47                                &ctx->encryptionType);
  48     if (GSS_ERROR(major))
  49         return major;
  50
  51     gssEapReleaseName(&tmpMinor, &ctx->initiatorName);
  52
  53     vp = rc_avpair_get(ctx->acceptorCtx.avps, PW_USER_NAME, 0);
  54     if (vp != NULL) {
  55         nameBuf.length = vp->lvalue;
  56         nameBuf.value = vp->strvalue;
  57     } else {
  58         ctx->gssFlags |= GSS_C_ANON_FLAG;
  59     }
  60
  61     major = gssEapImportName(minor, &nameBuf, GSS_C_NT_USER_NAME,
  62                              &ctx->initiatorName);
  63     if (GSS_ERROR(major))
  64         return major;
  65
  66     ctx->initiatorName->attrCtx = gssEapCreateAttrContext(cred, ctx);
  67
  68     vp = rc_avpair_get(ctx->acceptorCtx.avps,
  69                        VENDOR_ATTR_MS_MPPE_SEND_KEY,
  70                        VENDOR_ID_MICROSOFT);
  71     if (ctx->encryptionType != ENCTYPE_NULL && vp != NULL) {
  72         major = gssEapDeriveRfc3961Key(minor,
  73                                        (unsigned char *)vp->strvalue,
  74                                        vp->lvalue,
  75                                        ctx->encryptionType,
  76                                        &ctx->rfc3961Key);
  77         if (GSS_ERROR(major))
  78             return major;
  79
  80         major = rfc3961ChecksumTypeForKey(minor, &ctx->rfc3961Key,
  81                                            &ctx->checksumType);
  82         if (GSS_ERROR(major))
  83             return major;
  84     } else {
  85         /*
  86          * draft-howlett-eap-gss says that integrity/confidentialty should
  87          * always be advertised as available, but if we have no keying
  88          * material it seems confusing to the caller to advertise this.
  89          */
  90         ctx->gssFlags &= ~(GSS_C_INTEG_FLAG | GSS_C_CONF_FLAG);
  91         ctx->encryptionType = ENCTYPE_NULL;
  92     }
  93
  94     major = sequenceInit(minor,
  95                          &ctx->seqState, ctx->recvSeq,
  96                          ((ctx->gssFlags & GSS_C_REPLAY_FLAG) != 0),
  97                          ((ctx->gssFlags & GSS_C_SEQUENCE_FLAG) != 0),
  98                          TRUE);
  99     if (GSS_ERROR(major))
 100         return major;
 101
 102     return GSS_S_COMPLETE;
 103 }
 104
 105 static OM_uint32
 106 eapGssSmAcceptIdentity(OM_uint32 *minor,
 107                        gss_ctx_id_t ctx,
 108                        gss_cred_id_t cred,
 109                        gss_buffer_t inputToken,
 110                        gss_channel_bindings_t chanBindings,
 111                        gss_buffer_t outputToken)
 112 {
 113     OM_uint32 major;
 114     union {
 115         struct eap_hdr pdu;
 116         unsigned char data[5];
 117     } pkt;
 118     gss_buffer_desc pktBuffer;
 119
 120     if (inputToken != GSS_C_NO_BUFFER && inputToken->length != 0)
 121         return GSS_S_DEFECTIVE_TOKEN;
 122
 123     assert(ctx->acceptorCtx.radHandle == NULL);
 124
 125     major = gssEapRadiusAllocHandle(minor, cred, &ctx->acceptorCtx.radHandle);
 126     if (GSS_ERROR(major))
 127         return major;
 128
 129     assert(ctx->acceptorName == GSS_C_NO_NAME);
 130
 131     if (cred != GSS_C_NO_CREDENTIAL && cred->name != GSS_C_NO_NAME) {
 132         major = gssEapDuplicateName(minor, cred->name, &ctx->acceptorName);
 133         if (GSS_ERROR(major))
 134             return major;
 135     }
 136
 137     pkt.pdu.code = EAP_CODE_REQUEST;
 138     pkt.pdu.identifier = 0;
 139     pkt.pdu.length = htons(sizeof(pkt.data));
 140     pkt.data[4] = EAP_TYPE_IDENTITY;
 141
 142     pktBuffer.length = sizeof(pkt.data);
 143     pktBuffer.value = pkt.data;
 144
 145     major = duplicateBuffer(minor, &pktBuffer, outputToken);
 146     if (GSS_ERROR(major))
 147         return major;
 148
 149     ctx->state = EAP_STATE_AUTHENTICATE;
 150
 151     return GSS_S_CONTINUE_NEEDED;
 152 }
 153
 154 static OM_uint32
 155 setAcceptorIdentity(OM_uint32 *minor,
 156                     gss_ctx_id_t ctx,
 157                     VALUE_PAIR **avps)
 158 {
 159     OM_uint32 major;
 160     gss_buffer_desc nameBuf;
 161     krb5_context krbContext = NULL;
 162     krb5_principal krbPrinc;
 163
 164     /* Awaits further specification */
 165     if (ctx->acceptorName == GSS_C_NO_NAME)
 166         return GSS_S_COMPLETE;
 167
 168     GSSEAP_KRB_INIT(&krbContext);
 169
 170     krbPrinc = ctx->acceptorName->krbPrincipal;
 171     assert(krbPrinc != NULL);
 172
 173     if (krb5_princ_size(krbContext, krbPrinc) < 2)
 174         return GSS_S_BAD_NAME;
 175
 176     /* Acceptor-Service-Name */
 177     krbDataToGssBuffer(krb5_princ_component(krbContext, krbPrinc, 0), &nameBuf);
 178
 179     major = addAvpFromBuffer(minor, ctx->acceptorCtx.radHandle, avps,
 180                              VENDOR_ATTR_GSS_ACCEPTOR_SERVICE_NAME,
 181                              VENDOR_ID_UKERNA,
 182                              &nameBuf);
 183     if (GSS_ERROR(major))
 184         return major;
 185
 186     /* Acceptor-Host-Name */
 187     krbDataToGssBuffer(krb5_princ_component(krbContext, krbPrinc, 1), &nameBuf);
 188
 189     major = addAvpFromBuffer(minor, ctx->acceptorCtx.radHandle, avps,
 190                              VENDOR_ATTR_GSS_ACCEPTOR_HOST_NAME,
 191                              VENDOR_ID_UKERNA,
 192                              &nameBuf);
 193     if (GSS_ERROR(major))
 194         return major;
 195
 196     if (krb5_princ_size(krbContext, krbPrinc) > 2) {
 197         /* Acceptor-Service-Specific */
 198         krb5_principal_data ssiPrinc = *krbPrinc;
 199         char *ssi;
 200
 201         krb5_princ_size(krbContext, &ssiPrinc) -= 2;
 202         krb5_princ_name(krbContext, &ssiPrinc) += 2;
 203
 204         *minor = krb5_unparse_name_flags(krbContext, &ssiPrinc,
 205                                          KRB5_PRINCIPAL_UNPARSE_NO_REALM, &ssi);
 206         if (*minor != 0)
 207             return GSS_S_FAILURE;
 208
 209         nameBuf.value = ssi;
 210         nameBuf.length = strlen(ssi);
 211
 212         major = addAvpFromBuffer(minor, ctx->acceptorCtx.radHandle, avps,
 213                                  VENDOR_ATTR_GSS_ACCEPTOR_SERVICE_SPECIFIC,
 214                                  VENDOR_ID_UKERNA,
 215                                  &nameBuf);
 216
 217         if (GSS_ERROR(major)) {
 218             krb5_free_unparsed_name(krbContext, ssi);
 219             return major;
 220         }
 221         krb5_free_unparsed_name(krbContext, ssi);
 222     }
 223
 224     krbDataToGssBuffer(krb5_princ_realm(krbContext, krbPrinc), &nameBuf);
 225     if (nameBuf.length != 0) {
 226         /* Acceptor-Realm-Name */
 227         major = addAvpFromBuffer(minor, ctx->acceptorCtx.radHandle, avps,
 228                                  VENDOR_ATTR_GSS_ACCEPTOR_REALM_NAME,
 229                                  VENDOR_ID_UKERNA,
 230                                  &nameBuf);
 231         if (GSS_ERROR(major))
 232             return major;
 233     }
 234
 235     return GSS_S_COMPLETE;
 236 }
 237
 238 static OM_uint32
 239 eapGssSmAcceptAuthenticate(OM_uint32 *minor,
 240                            gss_ctx_id_t ctx,
 241                            gss_cred_id_t cred,
 242                            gss_buffer_t inputToken,
 243                            gss_channel_bindings_t chanBindings,
 244                            gss_buffer_t outputToken)
 245 {
 246     OM_uint32 major, tmpMinor;
 247     int code;
 248     VALUE_PAIR *send = NULL;
 249     VALUE_PAIR *received = NULL;
 250     rc_handle *rh = ctx->acceptorCtx.radHandle;
 251     char msgBuffer[4096];
 252     struct eap_hdr *pdu;
 253     unsigned char *pos;
 254     gss_buffer_desc nameBuf = GSS_C_EMPTY_BUFFER;
 255
 256     pdu = (struct eap_hdr *)inputToken->value;
 257     pos = (unsigned char *)(pdu + 1);
 258
 259     if (inputToken->length > sizeof(*pdu) &&
 260         pdu->code == EAP_CODE_RESPONSE &&
 261         pos[0] == EAP_TYPE_IDENTITY) {
 262         /*
 263          * XXX TODO do we really need to set User-Name? FreeRADIUS does
 264          * not appear to require it.
 265          */
 266         major = addAvpFromBuffer(minor, rh, &send, PW_USER_NAME, 0, &nameBuf);
 267         if (GSS_ERROR(major))
 268             goto cleanup;
 269
 270         major = setAcceptorIdentity(minor, ctx, &send);
 271         if (GSS_ERROR(major))
 272             goto cleanup;
 273     }
 274
 275     major = addAvpFromBuffer(minor, rh, &send, PW_EAP_MESSAGE, 0, inputToken);
 276     if (GSS_ERROR(major))
 277         goto cleanup;
 278
 279     if (ctx->acceptorCtx.lastStatus == CHALLENGE_RC) {
 280         major = addAvpFromBuffer(minor, rh, &send, PW_STATE, 0,
 281                                  &ctx->acceptorCtx.state);
 282         if (GSS_ERROR(major))
 283             goto cleanup;
 284
 285         gss_release_buffer(&tmpMinor, &ctx->acceptorCtx.state);
 286     }
 287
 288     code = rc_auth(rh, 0, send, &received, msgBuffer);
 289     switch (code) {
 290     case OK_RC:
 291     case CHALLENGE_RC:
 292         major = GSS_S_CONTINUE_NEEDED;
 293         break;
 294     case TIMEOUT_RC:
 295         major = GSS_S_UNAVAILABLE;
 296         break;
 297     case REJECT_RC:
 298         major = GSS_S_DEFECTIVE_CREDENTIAL;
 299         break;
 300     default:
 301         major = GSS_S_FAILURE;
 302         goto cleanup;
 303     }
 304
 305     if (GSS_ERROR(major))
 306         goto cleanup;
 307
 308     ctx->acceptorCtx.lastStatus = code;
 309
 310     major = getBufferFromAvps(minor, received, PW_EAP_MESSAGE, 0,
 311                               outputToken, TRUE);
 312     if ((major == GSS_S_UNAVAILABLE && code != OK_RC) ||
 313         GSS_ERROR(major))
 314         goto cleanup;
 315
 316     if (code == CHALLENGE_RC) {
 317         major = getBufferFromAvps(minor, received, PW_STATE, 0,
 318                                   &ctx->acceptorCtx.state, TRUE);
 319         if (major != GSS_S_UNAVAILABLE && GSS_ERROR(major))
 320             goto cleanup;
 321     } else {
 322         ctx->acceptorCtx.avps = received;
 323         received = NULL;
 324
 325         major = acceptReady(minor, ctx, cred);
 326         if (GSS_ERROR(major))
 327             goto cleanup;
 328
 329         ctx->state = EAP_STATE_GSS_CHANNEL_BINDINGS;
 330     }
 331
 332     major = GSS_S_CONTINUE_NEEDED;
 333
 334 cleanup:
 335     if (received != NULL)
 336         rc_avpair_free(received);
 337
 338     return major;
 339 }
 340
 341 static OM_uint32
 342 eapGssSmAcceptGssChannelBindings(OM_uint32 *minor,
 343                                  gss_ctx_id_t ctx,
 344                                  gss_cred_id_t cred,
 345                                  gss_buffer_t inputToken,
 346                                  gss_channel_bindings_t chanBindings,
 347                                  gss_buffer_t outputToken)
 348 {
 349     OM_uint32 major;
 350     gss_iov_buffer_desc iov[2];
 351
 352     outputToken->length = 0;
 353     outputToken->value = NULL;
 354
 355     if (chanBindings == GSS_C_NO_CHANNEL_BINDINGS) {
 356         ctx->state = EAP_STATE_ESTABLISHED;
 357         return GSS_S_COMPLETE;
 358     }
 359
 360     if (inputToken->length < 14) {
 361         return GSS_S_DEFECTIVE_TOKEN;
 362     }
 363
 364     iov[0].type = GSS_IOV_BUFFER_TYPE_DATA;
 365     iov[0].buffer.length = 0;
 366     iov[0].buffer.value = NULL;
 367
 368     if (chanBindings != GSS_C_NO_CHANNEL_BINDINGS)
 369         iov[0].buffer = chanBindings->application_data;
 370
 371     iov[1].type = GSS_IOV_BUFFER_TYPE_HEADER;
 372     iov[1].buffer.length = 16;
 373     iov[1].buffer.value = (unsigned char *)inputToken->value - 2;
 374
 375     assert(load_uint16_be(iov[1].buffer.value) == TOK_TYPE_GSS_CB);
 376
 377     iov[2].type = GSS_IOV_BUFFER_TYPE_TRAILER;
 378     iov[2].buffer.length = inputToken->length - 14;
 379     iov[2].buffer.value = (unsigned char *)inputToken->value + 14;
 380
 381     major = gssEapUnwrapOrVerifyMIC(minor, ctx, NULL, NULL,
 382                                     iov, 3, TOK_TYPE_GSS_CB);
 383     if (major == GSS_S_COMPLETE) {
 384         ctx->state = EAP_STATE_ESTABLISHED;
 385     }
 386
 387 #if 0
 388     gss_release_buffer(&tmpMinor, &iov[0].buffer);
 389 #endif
 390
 391     return major;
 392 }
 393
 394 static OM_uint32
 395 eapGssSmAcceptEstablished(OM_uint32 *minor,
 396                           gss_ctx_id_t ctx,
 397                           gss_cred_id_t cred,
 398                           gss_buffer_t inputToken,
 399                           gss_channel_bindings_t chanBindings,
 400                           gss_buffer_t outputToken)
 401 {
 402     /* Called with already established context */
 403     *minor = EINVAL;
 404     return GSS_S_BAD_STATUS;
 405 }
 406
 407 static struct gss_eap_acceptor_sm {
 408     enum gss_eap_token_type inputTokenType;
 409     enum gss_eap_token_type outputTokenType;
 410     OM_uint32 (*processToken)(OM_uint32 *,
 411                               gss_ctx_id_t,
 412                               gss_cred_id_t,
 413                               gss_buffer_t,
 414                               gss_channel_bindings_t,
 415                               gss_buffer_t);
 416 } eapGssAcceptorSm[] = {
 417     { TOK_TYPE_EAP_RESP,    TOK_TYPE_EAP_REQ,  eapGssSmAcceptIdentity           },
 418     { TOK_TYPE_EAP_RESP,    TOK_TYPE_EAP_REQ,  eapGssSmAcceptAuthenticate       },
 419     { TOK_TYPE_GSS_CB,      TOK_TYPE_NONE,     eapGssSmAcceptGssChannelBindings },
 420     { TOK_TYPE_NONE,        TOK_TYPE_NONE,     eapGssSmAcceptEstablished        },
 421 };
 422
 423 OM_uint32
 424 gss_accept_sec_context(OM_uint32 *minor,
 425                        gss_ctx_id_t *context_handle,
 426                        gss_cred_id_t cred,
 427                        gss_buffer_t input_token,
 428                        gss_channel_bindings_t input_chan_bindings,
 429                        gss_name_t *src_name,
 430                        gss_OID *mech_type,
 431                        gss_buffer_t output_token,
 432                        OM_uint32 *ret_flags,
 433                        OM_uint32 *time_rec,
 434                        gss_cred_id_t *delegated_cred_handle)
 435 {
 436     OM_uint32 major;
 437     OM_uint32 tmpMajor, tmpMinor;
 438     gss_ctx_id_t ctx = *context_handle;
 439     struct gss_eap_acceptor_sm *sm = NULL;
 440     gss_buffer_desc innerInputToken = GSS_C_EMPTY_BUFFER;
 441     gss_buffer_desc innerOutputToken = GSS_C_EMPTY_BUFFER;
 442
 443     *minor = 0;
 444
 445     output_token->length = 0;
 446     output_token->value = NULL;
 447
 448     if (cred != GSS_C_NO_CREDENTIAL && !(cred->flags & CRED_FLAG_ACCEPT)) {
 449         return GSS_S_NO_CRED;
 450     }
 451
 452     if (input_token == GSS_C_NO_BUFFER || input_token->length == 0) {
 453         return GSS_S_DEFECTIVE_TOKEN;
 454     }
 455
 456     if (ctx == GSS_C_NO_CONTEXT) {
 457         major = gssEapAllocContext(minor, &ctx);
 458         if (GSS_ERROR(major))
 459             return major;
 460
 461         *context_handle = ctx;
 462     }
 463
 464     GSSEAP_MUTEX_LOCK(&ctx->mutex);
 465
 466     sm = &eapGssAcceptorSm[ctx->state];
 467
 468     major = gssEapVerifyToken(minor, ctx, input_token,
 469                               sm->inputTokenType, &innerInputToken);
 470     if (GSS_ERROR(major))
 471         goto cleanup;
 472
 473     /* If credentials were provided, check they're usable with this mech */
 474     if (!gssEapCredAvailable(cred, ctx->mechanismUsed)) {
 475         major = GSS_S_BAD_MECH;
 476         goto cleanup;
 477     }
 478
 479     do {
 480         sm = &eapGssAcceptorSm[ctx->state];
 481
 482         major = (sm->processToken)(minor,
 483                                    ctx,
 484                                    cred,
 485                                    &innerInputToken,
 486                                    input_chan_bindings,
 487                                    &innerOutputToken);
 488         if (GSS_ERROR(major))
 489             goto cleanup;
 490     } while (major == GSS_S_CONTINUE_NEEDED && innerOutputToken.length == 0);
 491
 492     if (mech_type != NULL) {
 493         if (!gssEapInternalizeOid(ctx->mechanismUsed, mech_type))
 494             duplicateOid(&tmpMinor, ctx->mechanismUsed, mech_type);
 495     }
 496     if (innerOutputToken.length != 0) {
 497         tmpMajor = gssEapMakeToken(&tmpMinor, ctx, &innerOutputToken,
 498                                    sm->outputTokenType, output_token);
 499         if (GSS_ERROR(tmpMajor)) {
 500             major = tmpMajor;
 501             *minor = tmpMinor;
 502             goto cleanup;
 503         }
 504     }
 505     if (ret_flags != NULL)
 506         *ret_flags = ctx->gssFlags;
 507     if (delegated_cred_handle != NULL)
 508         *delegated_cred_handle = GSS_C_NO_CREDENTIAL;
 509
 510     if (major == GSS_S_COMPLETE) {
 511         if (src_name != NULL && ctx->initiatorName != GSS_C_NO_NAME) {
 512             major = gssEapDuplicateName(&tmpMinor, ctx->initiatorName, src_name);
 513             if (GSS_ERROR(major))
 514                 goto cleanup;
 515         }
 516         if (time_rec != NULL)
 517             gssEapContextTime(&tmpMinor, ctx, time_rec);
 518     }
 519
 520     assert(ctx->state == EAP_STATE_ESTABLISHED || major == GSS_S_CONTINUE_NEEDED);
 521
 522 cleanup:
 523     GSSEAP_MUTEX_UNLOCK(&ctx->mutex);
 524
 525     if (GSS_ERROR(major))
 526         gssEapReleaseContext(&tmpMinor, context_handle);
 527
 528     gss_release_buffer(&tmpMinor, &innerOutputToken);
 529
 530     return major;
 531 }
 532