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 #define RC_CONFIG_FILE      SYSCONFDIR "/radiusclient/radiusclient.conf"
  36
  37 /*
  38  * Mark a context as ready for cryptographic operations
  39  */
  40 static OM_uint32
  41 acceptReady(OM_uint32 *minor, gss_ctx_id_t ctx, gss_cred_id_t cred)
  42 {
  43     OM_uint32 major;
  44     VALUE_PAIR *vp;
  45     gss_buffer_desc nameBuf = GSS_C_EMPTY_BUFFER;
  46
  47     /* Cache encryption type derived from selected mechanism OID */
  48     major = gssEapOidToEnctype(minor, ctx->mechanismUsed,
  49                                &ctx->encryptionType);
  50     if (GSS_ERROR(major))
  51         return major;
  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 if (ctx->initiatorName == GSS_C_NO_NAME) {
  58         ctx->gssFlags |= GSS_C_ANON_FLAG;
  59     }
  60
  61     if (nameBuf.length != 0 || ctx->initiatorName == GSS_C_NO_NAME) {
  62         major = gssEapImportName(minor, &nameBuf, GSS_C_NT_USER_NAME,
  63                                  &ctx->initiatorName);
  64         if (GSS_ERROR(major))
  65             return major;
  66     }
  67
  68     ctx->initiatorName->attrCtx = gssEapCreateAttrContext(cred, ctx);
  69
  70     vp = rc_avpair_get(ctx->acceptorCtx.avps, 0x01370010, 0);
  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     rc_handle *rh;
 115     union {
 116         struct eap_hdr pdu;
 117         unsigned char data[5];
 118     } pkt;
 119     gss_buffer_desc pktBuffer;
 120     char *config = RC_CONFIG_FILE;
 121
 122     if (inputToken != GSS_C_NO_BUFFER && inputToken->length != 0)
 123         return GSS_S_DEFECTIVE_TOKEN;
 124
 125     assert(ctx->acceptorCtx.radHandle == NULL);
 126
 127     if (cred != GSS_C_NO_CREDENTIAL && cred->radiusConfigFile != NULL)
 128         config = cred->radiusConfigFile;
 129
 130     rh = ctx->acceptorCtx.radHandle = rc_read_config(config);
 131     if (rh == NULL) {
 132         *minor = errno;
 133         return GSS_S_FAILURE;
 134     }
 135
 136     if (rc_read_dictionary(rh, rc_conf_str(rh, "dictionary")) != 0) {
 137         *minor = errno;
 138         return GSS_S_FAILURE;
 139     }
 140
 141     if (ctx->acceptorName == GSS_C_NO_NAME &&
 142         cred != GSS_C_NO_CREDENTIAL &&
 143         cred->name != GSS_C_NO_NAME) {
 144         major = gss_duplicate_name(minor, cred->name, &ctx->acceptorName);
 145         if (GSS_ERROR(major))
 146             return major;
 147     }
 148
 149     pkt.pdu.code = EAP_CODE_REQUEST;
 150     pkt.pdu.identifier = 0;
 151     pkt.pdu.length = htons(sizeof(pkt.data));
 152     pkt.data[4] = EAP_TYPE_IDENTITY;
 153
 154     pktBuffer.length = sizeof(pkt.data);
 155     pktBuffer.value = pkt.data;
 156
 157     major = duplicateBuffer(minor, &pktBuffer, outputToken);
 158     if (GSS_ERROR(major))
 159         return major;
 160
 161     ctx->state = EAP_STATE_AUTHENTICATE;
 162
 163     return GSS_S_CONTINUE_NEEDED;
 164 }
 165
 166 static OM_uint32
 167 importInitiatorIdentity(OM_uint32 *minor,
 168                         gss_ctx_id_t ctx,
 169                         gss_buffer_t inputToken,
 170                         gss_buffer_t nameBuf)
 171 {
 172     OM_uint32 major, tmpMinor;
 173     struct eap_hdr *pdu = (struct eap_hdr *)inputToken->value;
 174     unsigned char *pos = (unsigned char *)(pdu + 1);
 175     gss_name_t name;
 176
 177     assert(pdu->code == EAP_CODE_RESPONSE);
 178     assert(pos[0] == EAP_TYPE_IDENTITY);
 179
 180     nameBuf->value = pos + 1;
 181     nameBuf->length = inputToken->length - sizeof(*pdu) - 1;
 182
 183     major = gssEapImportName(minor, nameBuf, GSS_C_NT_USER_NAME, &name);
 184     if (GSS_ERROR(major))
 185         return major;
 186
 187     gssEapReleaseName(&tmpMinor, &ctx->initiatorName);
 188     ctx->initiatorName = name;
 189
 190     return GSS_S_COMPLETE;
 191 }
 192
 193 static OM_uint32
 194 eapGssSmAcceptAuthenticate(OM_uint32 *minor,
 195                            gss_ctx_id_t ctx,
 196                            gss_cred_id_t cred,
 197                            gss_buffer_t inputToken,
 198                            gss_channel_bindings_t chanBindings,
 199                            gss_buffer_t outputToken)
 200 {
 201     OM_uint32 major, tmpMinor;
 202     int code;
 203     VALUE_PAIR *send = NULL;
 204     VALUE_PAIR *received = NULL;
 205     rc_handle *rh = ctx->acceptorCtx.radHandle;
 206     char msgBuffer[4096];
 207     struct eap_hdr *pdu;
 208     unsigned char *pos;
 209     gss_buffer_desc nameBuf = GSS_C_EMPTY_BUFFER;
 210
 211     pdu = (struct eap_hdr *)inputToken->value;
 212     pos = (unsigned char *)(pdu + 1);
 213
 214     if (inputToken->length > sizeof(*pdu) &&
 215         pdu->code == EAP_CODE_RESPONSE &&
 216         pos[0] == EAP_TYPE_IDENTITY) {
 217         major = importInitiatorIdentity(minor, ctx, inputToken, &nameBuf);
 218         if (GSS_ERROR(major))
 219             goto cleanup;
 220
 221         major = addAvpFromBuffer(minor, rh, &send, PW_USER_NAME, &nameBuf);
 222         if (GSS_ERROR(major))
 223             goto cleanup;
 224     }
 225
 226     major = addAvpFromBuffer(minor, rh, &send, PW_EAP_MESSAGE, inputToken);
 227     if (GSS_ERROR(major))
 228         goto cleanup;
 229
 230     if (ctx->acceptorCtx.lastStatus == CHALLENGE_RC) {
 231         major = addAvpFromBuffer(minor, rh, &send, PW_STATE,
 232                                  &ctx->acceptorCtx.state);
 233         if (GSS_ERROR(major))
 234             goto cleanup;
 235
 236         gss_release_buffer(&tmpMinor, &ctx->acceptorCtx.state);
 237     }
 238
 239     code = rc_auth(rh, 0, send, &received, msgBuffer);
 240     switch (code) {
 241     case OK_RC:
 242     case CHALLENGE_RC:
 243         major = GSS_S_CONTINUE_NEEDED;
 244         break;
 245     case TIMEOUT_RC:
 246         major = GSS_S_UNAVAILABLE;
 247         break;
 248     case REJECT_RC:
 249         major = GSS_S_DEFECTIVE_CREDENTIAL;
 250         break;
 251     default:
 252         major = GSS_S_FAILURE;
 253         goto cleanup;
 254     }
 255
 256     if (GSS_ERROR(major))
 257         goto cleanup;
 258
 259     ctx->acceptorCtx.lastStatus = code;
 260
 261     major = getBufferFromAvps(minor, received, PW_EAP_MESSAGE,
 262                               outputToken, TRUE);
 263     if ((major == GSS_S_UNAVAILABLE && code != OK_RC) ||
 264         GSS_ERROR(major))
 265         goto cleanup;
 266
 267     if (code == CHALLENGE_RC) {
 268         major = getBufferFromAvps(minor, received, PW_STATE,
 269                                   &ctx->acceptorCtx.state, TRUE);
 270         if (major != GSS_S_UNAVAILABLE && GSS_ERROR(major))
 271             goto cleanup;
 272     } else {
 273         ctx->acceptorCtx.avps = received;
 274         received = NULL;
 275
 276         major = acceptReady(minor, ctx, cred);
 277         if (GSS_ERROR(major))
 278             goto cleanup;
 279
 280         ctx->state = EAP_STATE_GSS_CHANNEL_BINDINGS;
 281     }
 282
 283     major = GSS_S_CONTINUE_NEEDED;
 284
 285 cleanup:
 286     if (received != NULL)
 287         rc_avpair_free(received);
 288
 289     return major;
 290 }
 291
 292 static OM_uint32
 293 eapGssSmAcceptGssChannelBindings(OM_uint32 *minor,
 294                                  gss_ctx_id_t ctx,
 295                                  gss_cred_id_t cred,
 296                                  gss_buffer_t inputToken,
 297                                  gss_channel_bindings_t chanBindings,
 298                                  gss_buffer_t outputToken)
 299 {
 300     OM_uint32 major;
 301     gss_iov_buffer_desc iov[2];
 302
 303     outputToken->length = 0;
 304     outputToken->value = NULL;
 305
 306     if (chanBindings == GSS_C_NO_CHANNEL_BINDINGS) {
 307         ctx->state = EAP_STATE_ESTABLISHED;
 308         return GSS_S_COMPLETE;
 309     }
 310
 311     if (inputToken->length < 14) {
 312         return GSS_S_DEFECTIVE_TOKEN;
 313     }
 314
 315     iov[0].type = GSS_IOV_BUFFER_TYPE_DATA;
 316     iov[0].buffer.length = 0;
 317     iov[0].buffer.value = NULL;
 318
 319     if (chanBindings != GSS_C_NO_CHANNEL_BINDINGS)
 320         iov[0].buffer = chanBindings->application_data;
 321
 322     iov[1].type = GSS_IOV_BUFFER_TYPE_HEADER;
 323     iov[1].buffer.length = 16;
 324     iov[1].buffer.value = (unsigned char *)inputToken->value - 2;
 325
 326     assert(load_uint16_be(iov[1].buffer.value) == TOK_TYPE_GSS_CB);
 327
 328     iov[2].type = GSS_IOV_BUFFER_TYPE_TRAILER;
 329     iov[2].buffer.length = inputToken->length - 14;
 330     iov[2].buffer.value = (unsigned char *)inputToken->value + 14;
 331
 332     major = gssEapUnwrapOrVerifyMIC(minor, ctx, NULL, NULL,
 333                                     iov, 3, TOK_TYPE_GSS_CB);
 334     if (major == GSS_S_COMPLETE) {
 335         ctx->state = EAP_STATE_ESTABLISHED;
 336     }
 337
 338 #if 0
 339     gss_release_buffer(&tmpMinor, &iov[0].buffer);
 340 #endif
 341
 342     return major;
 343 }
 344
 345 static OM_uint32
 346 eapGssSmAcceptEstablished(OM_uint32 *minor,
 347                           gss_ctx_id_t ctx,
 348                           gss_cred_id_t cred,
 349                           gss_buffer_t inputToken,
 350                           gss_channel_bindings_t chanBindings,
 351                           gss_buffer_t outputToken)
 352 {
 353     /* Called with already established context */
 354     *minor = EINVAL;
 355     return GSS_S_BAD_STATUS;
 356 }
 357
 358 static struct gss_eap_acceptor_sm {
 359     enum gss_eap_token_type inputTokenType;
 360     enum gss_eap_token_type outputTokenType;
 361     OM_uint32 (*processToken)(OM_uint32 *,
 362                               gss_ctx_id_t,
 363                               gss_cred_id_t,
 364                               gss_buffer_t,
 365                               gss_channel_bindings_t,
 366                               gss_buffer_t);
 367 } eapGssAcceptorSm[] = {
 368     { TOK_TYPE_EAP_RESP,    TOK_TYPE_EAP_REQ,  eapGssSmAcceptIdentity           },
 369     { TOK_TYPE_EAP_RESP,    TOK_TYPE_EAP_REQ,  eapGssSmAcceptAuthenticate       },
 370     { TOK_TYPE_GSS_CB,      TOK_TYPE_NONE,     eapGssSmAcceptGssChannelBindings },
 371     { TOK_TYPE_NONE,        TOK_TYPE_NONE,     eapGssSmAcceptEstablished        },
 372 };
 373
 374 OM_uint32
 375 gss_accept_sec_context(OM_uint32 *minor,
 376                        gss_ctx_id_t *context_handle,
 377                        gss_cred_id_t cred,
 378                        gss_buffer_t input_token,
 379                        gss_channel_bindings_t input_chan_bindings,
 380                        gss_name_t *src_name,
 381                        gss_OID *mech_type,
 382                        gss_buffer_t output_token,
 383                        OM_uint32 *ret_flags,
 384                        OM_uint32 *time_rec,
 385                        gss_cred_id_t *delegated_cred_handle)
 386 {
 387     OM_uint32 major;
 388     OM_uint32 tmpMajor, tmpMinor;
 389     gss_ctx_id_t ctx = *context_handle;
 390     struct gss_eap_acceptor_sm *sm = NULL;
 391     gss_buffer_desc innerInputToken = GSS_C_EMPTY_BUFFER;
 392     gss_buffer_desc innerOutputToken = GSS_C_EMPTY_BUFFER;
 393
 394     *minor = 0;
 395
 396     output_token->length = 0;
 397     output_token->value = NULL;
 398
 399     if (cred != GSS_C_NO_CREDENTIAL && !(cred->flags & CRED_FLAG_ACCEPT)) {
 400         return GSS_S_NO_CRED;
 401     }
 402
 403     if (input_token == GSS_C_NO_BUFFER || input_token->length == 0) {
 404         return GSS_S_DEFECTIVE_TOKEN;
 405     }
 406
 407     if (ctx == GSS_C_NO_CONTEXT) {
 408         major = gssEapAllocContext(minor, &ctx);
 409         if (GSS_ERROR(major))
 410             return major;
 411
 412         *context_handle = ctx;
 413     }
 414
 415     GSSEAP_MUTEX_LOCK(&ctx->mutex);
 416
 417     sm = &eapGssAcceptorSm[ctx->state];
 418
 419     major = gssEapVerifyToken(minor, ctx, input_token,
 420                               sm->inputTokenType, &innerInputToken);
 421     if (GSS_ERROR(major))
 422         goto cleanup;
 423
 424     /* If credentials were provided, check they're usable with this mech */
 425     if (!gssEapCredAvailable(cred, ctx->mechanismUsed)) {
 426         major = GSS_S_BAD_MECH;
 427         goto cleanup;
 428     }
 429
 430     do {
 431         sm = &eapGssAcceptorSm[ctx->state];
 432
 433         major = (sm->processToken)(minor,
 434                                    ctx,
 435                                    cred,
 436                                    &innerInputToken,
 437                                    input_chan_bindings,
 438                                    &innerOutputToken);
 439         if (GSS_ERROR(major))
 440             goto cleanup;
 441     } while (major == GSS_S_CONTINUE_NEEDED && innerOutputToken.length == 0);
 442
 443     if (mech_type != NULL) {
 444         if (!gssEapInternalizeOid(ctx->mechanismUsed, mech_type))
 445             duplicateOid(&tmpMinor, ctx->mechanismUsed, mech_type);
 446     }
 447     if (innerOutputToken.length != 0) {
 448         tmpMajor = gssEapMakeToken(&tmpMinor, ctx, &innerOutputToken,
 449                                    sm->outputTokenType, output_token);
 450         if (GSS_ERROR(tmpMajor)) {
 451             major = tmpMajor;
 452             *minor = tmpMinor;
 453             goto cleanup;
 454         }
 455     }
 456     if (ret_flags != NULL)
 457         *ret_flags = ctx->gssFlags;
 458     if (delegated_cred_handle != NULL)
 459         *delegated_cred_handle = GSS_C_NO_CREDENTIAL;
 460
 461     if (major == GSS_S_COMPLETE) {
 462         if (src_name != NULL && ctx->initiatorName != GSS_C_NO_NAME) {
 463             major = gss_duplicate_name(&tmpMinor, ctx->initiatorName, src_name);
 464             if (GSS_ERROR(major))
 465                 goto cleanup;
 466         }
 467         if (time_rec != NULL)
 468             gss_context_time(&tmpMinor, ctx, time_rec);
 469     }
 470
 471     assert(ctx->state == EAP_STATE_ESTABLISHED || major == GSS_S_CONTINUE_NEEDED);
 472
 473 cleanup:
 474     GSSEAP_MUTEX_UNLOCK(&ctx->mutex);
 475
 476     if (GSS_ERROR(major))
 477         gssEapReleaseContext(&tmpMinor, context_handle);
 478
 479     gss_release_buffer(&tmpMinor, &innerOutputToken);
 480
 481     return major;
 482 }
 483