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