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)
  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     vp = rc_avpair_get(ctx->acceptorCtx.avps, 0x01370010, 0);
  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     }
  90
  91     major = sequenceInit(minor,
  92                          &ctx->seqState, ctx->recvSeq,
  93                          ((ctx->gssFlags & GSS_C_REPLAY_FLAG) != 0),
  94                          ((ctx->gssFlags & GSS_C_SEQUENCE_FLAG) != 0),
  95                          TRUE);
  96     if (GSS_ERROR(major))
  97         return major;
  98
  99     return GSS_S_COMPLETE;
 100 }
 101
 102 static OM_uint32
 103 eapGssSmAcceptIdentity(OM_uint32 *minor,
 104                        gss_ctx_id_t ctx,
 105                        gss_cred_id_t cred,
 106                        gss_buffer_t inputToken,
 107                        gss_channel_bindings_t chanBindings,
 108                        gss_buffer_t outputToken)
 109 {
 110     OM_uint32 major;
 111     rc_handle *rh;
 112     union {
 113         struct eap_hdr pdu;
 114         unsigned char data[5];
 115     } pkt;
 116     gss_buffer_desc pktBuffer;
 117     char *config = RC_CONFIG_FILE;
 118
 119     if (inputToken != GSS_C_NO_BUFFER && inputToken->length != 0)
 120         return GSS_S_DEFECTIVE_TOKEN;
 121
 122     assert(ctx->acceptorCtx.radHandle == NULL);
 123
 124     if (cred != GSS_C_NO_CREDENTIAL && cred->radiusConfigFile != NULL)
 125         config = cred->radiusConfigFile;
 126
 127     rh = ctx->acceptorCtx.radHandle = rc_read_config(config);
 128     if (rh == NULL) {
 129         *minor = errno;
 130         return GSS_S_FAILURE;
 131     }
 132
 133     if (rc_read_dictionary(rh, rc_conf_str(rh, "dictionary")) != 0) {
 134         *minor = errno;
 135         return GSS_S_FAILURE;
 136     }
 137
 138     if (ctx->acceptorName == GSS_C_NO_NAME &&
 139         cred != GSS_C_NO_CREDENTIAL &&
 140         cred->name != GSS_C_NO_NAME) {
 141         major = gss_duplicate_name(minor, cred->name, &ctx->acceptorName);
 142         if (GSS_ERROR(major))
 143             return major;
 144     }
 145
 146     pkt.pdu.code = EAP_CODE_REQUEST;
 147     pkt.pdu.identifier = 0;
 148     pkt.pdu.length = htons(sizeof(pkt.data));
 149     pkt.data[4] = EAP_TYPE_IDENTITY;
 150
 151     pktBuffer.length = sizeof(pkt.data);
 152     pktBuffer.value = pkt.data;
 153
 154     major = duplicateBuffer(minor, &pktBuffer, outputToken);
 155     if (GSS_ERROR(major))
 156         return major;
 157
 158     ctx->state = EAP_STATE_AUTHENTICATE;
 159
 160     return GSS_S_CONTINUE_NEEDED;
 161 }
 162
 163 static OM_uint32
 164 importInitiatorIdentity(OM_uint32 *minor,
 165                         gss_ctx_id_t ctx,
 166                         gss_buffer_t inputToken,
 167                         gss_buffer_t nameBuf)
 168 {
 169     OM_uint32 major, tmpMinor;
 170     struct eap_hdr *pdu = (struct eap_hdr *)inputToken->value;
 171     unsigned char *pos = (unsigned char *)(pdu + 1);
 172     gss_name_t name;
 173
 174     assert(pdu->code == EAP_CODE_RESPONSE);
 175     assert(pos[0] == EAP_TYPE_IDENTITY);
 176
 177     nameBuf->value = pos + 1;
 178     nameBuf->length = inputToken->length - sizeof(*pdu) - 1;
 179
 180     major = gssEapImportName(minor, nameBuf, GSS_C_NT_USER_NAME, &name);
 181     if (GSS_ERROR(major))
 182         return major;
 183
 184     gssEapReleaseName(&tmpMinor, &ctx->initiatorName);
 185     ctx->initiatorName = name;
 186
 187     return GSS_S_COMPLETE;
 188 }
 189
 190 static OM_uint32
 191 eapGssSmAcceptAuthenticate(OM_uint32 *minor,
 192                            gss_ctx_id_t ctx,
 193                            gss_cred_id_t cred,
 194                            gss_buffer_t inputToken,
 195                            gss_channel_bindings_t chanBindings,
 196                            gss_buffer_t outputToken)
 197 {
 198     OM_uint32 major, tmpMinor;
 199     int code;
 200     VALUE_PAIR *send = NULL;
 201     VALUE_PAIR *received = NULL;
 202     rc_handle *rh = ctx->acceptorCtx.radHandle;
 203     char msgBuffer[4096];
 204     struct eap_hdr *pdu;
 205     unsigned char *pos;
 206     gss_buffer_desc nameBuf = GSS_C_EMPTY_BUFFER;
 207
 208     pdu = (struct eap_hdr *)inputToken->value;
 209     pos = (unsigned char *)(pdu + 1);
 210
 211     if (inputToken->length > sizeof(*pdu) &&
 212         pdu->code == EAP_CODE_RESPONSE &&
 213         pos[0] == EAP_TYPE_IDENTITY) {
 214         major = importInitiatorIdentity(minor, ctx, inputToken, &nameBuf);
 215         if (GSS_ERROR(major))
 216             goto cleanup;
 217
 218         major = addAvpFromBuffer(minor, rh, &send, PW_USER_NAME, &nameBuf);
 219         if (GSS_ERROR(major))
 220             goto cleanup;
 221     }
 222
 223     major = addAvpFromBuffer(minor, rh, &send, PW_EAP_MESSAGE, inputToken);
 224     if (GSS_ERROR(major))
 225         goto cleanup;
 226
 227     if (ctx->acceptorCtx.lastStatus == CHALLENGE_RC) {
 228         major = addAvpFromBuffer(minor, rh, &send, PW_STATE,
 229                                  &ctx->acceptorCtx.state);
 230         if (GSS_ERROR(major))
 231             goto cleanup;
 232
 233         gss_release_buffer(&tmpMinor, &ctx->acceptorCtx.state);
 234     }
 235
 236     code = rc_auth(rh, 0, send, &received, msgBuffer);
 237     switch (code) {
 238     case OK_RC:
 239     case CHALLENGE_RC:
 240         major = GSS_S_CONTINUE_NEEDED;
 241         break;
 242     case TIMEOUT_RC:
 243         major = GSS_S_UNAVAILABLE;
 244         break;
 245     case REJECT_RC:
 246         major = GSS_S_DEFECTIVE_CREDENTIAL;
 247         break;
 248     default:
 249         major = GSS_S_FAILURE;
 250         goto cleanup;
 251     }
 252
 253     if (GSS_ERROR(major))
 254         goto cleanup;
 255
 256     ctx->acceptorCtx.lastStatus = code;
 257
 258     major = getBufferFromAvps(minor, received, PW_EAP_MESSAGE, outputToken);
 259     if (GSS_ERROR(major))
 260         goto cleanup;
 261
 262     if (code == CHALLENGE_RC) {
 263         major = getBufferFromAvps(minor, received, PW_STATE,
 264                                   &ctx->acceptorCtx.state);
 265         if (GSS_ERROR(major))
 266             goto cleanup;
 267     } else {
 268         ctx->acceptorCtx.avps = received;
 269         received = NULL;
 270
 271         major = acceptReady(minor, ctx);
 272         if (GSS_ERROR(major))
 273             goto cleanup;
 274
 275         ctx->state = EAP_STATE_GSS_CHANNEL_BINDINGS;
 276     }
 277
 278     major = GSS_S_CONTINUE_NEEDED;
 279
 280 cleanup:
 281     if (received != NULL)
 282         rc_avpair_free(received);
 283
 284     return major;
 285 }
 286
 287 static OM_uint32
 288 eapGssSmAcceptGssChannelBindings(OM_uint32 *minor,
 289                                  gss_ctx_id_t ctx,
 290                                  gss_cred_id_t cred,
 291                                  gss_buffer_t inputToken,
 292                                  gss_channel_bindings_t chanBindings,
 293                                  gss_buffer_t outputToken)
 294 {
 295     OM_uint32 major;
 296     gss_iov_buffer_desc iov[2];
 297
 298     outputToken->length = 0;
 299     outputToken->value = NULL;
 300
 301     if (chanBindings == GSS_C_NO_CHANNEL_BINDINGS) {
 302         ctx->state = EAP_STATE_ESTABLISHED;
 303         return GSS_S_COMPLETE;
 304     }
 305
 306     if (inputToken->length < 14) {
 307         return GSS_S_DEFECTIVE_TOKEN;
 308     }
 309
 310     iov[0].type = GSS_IOV_BUFFER_TYPE_DATA;
 311     iov[0].buffer.length = 0;
 312     iov[0].buffer.value = NULL;
 313
 314     if (chanBindings != GSS_C_NO_CHANNEL_BINDINGS)
 315         iov[0].buffer = chanBindings->application_data;
 316
 317     iov[1].type = GSS_IOV_BUFFER_TYPE_HEADER;
 318     iov[1].buffer.length = 16;
 319     iov[1].buffer.value = (unsigned char *)inputToken->value - 2;
 320
 321     assert(load_uint16_be(iov[1].buffer.value) == TOK_TYPE_GSS_CB);
 322
 323     iov[2].type = GSS_IOV_BUFFER_TYPE_TRAILER;
 324     iov[2].buffer.length = inputToken->length - 14;
 325     iov[2].buffer.value = (unsigned char *)inputToken->value + 14;
 326
 327     major = gssEapUnwrapOrVerifyMIC(minor, ctx, NULL, NULL,
 328                                     iov, 3, TOK_TYPE_GSS_CB);
 329     if (major == GSS_S_COMPLETE) {
 330         ctx->state = EAP_STATE_ESTABLISHED;
 331     }
 332
 333 #if 0
 334     gss_release_buffer(&tmpMinor, &iov[0].buffer);
 335 #endif
 336
 337     return major;
 338 }
 339
 340 static OM_uint32
 341 eapGssSmAcceptEstablished(OM_uint32 *minor,
 342                           gss_ctx_id_t ctx,
 343                           gss_cred_id_t cred,
 344                           gss_buffer_t inputToken,
 345                           gss_channel_bindings_t chanBindings,
 346                           gss_buffer_t outputToken)
 347 {
 348     /* Called with already established context */
 349     *minor = EINVAL;
 350     return GSS_S_BAD_STATUS;
 351 }
 352
 353 static struct gss_eap_acceptor_sm {
 354     enum gss_eap_token_type inputTokenType;
 355     enum gss_eap_token_type outputTokenType;
 356     OM_uint32 (*processToken)(OM_uint32 *,
 357                               gss_ctx_id_t,
 358                               gss_cred_id_t,
 359                               gss_buffer_t,
 360                               gss_channel_bindings_t,
 361                               gss_buffer_t);
 362 } eapGssAcceptorSm[] = {
 363     { TOK_TYPE_EAP_RESP,    TOK_TYPE_EAP_REQ,  eapGssSmAcceptIdentity           },
 364     { TOK_TYPE_EAP_RESP,    TOK_TYPE_EAP_REQ,  eapGssSmAcceptAuthenticate       },
 365     { TOK_TYPE_GSS_CB,      TOK_TYPE_NONE,     eapGssSmAcceptGssChannelBindings },
 366     { TOK_TYPE_NONE,        TOK_TYPE_NONE,     eapGssSmAcceptEstablished        },
 367 };
 368
 369 OM_uint32
 370 gss_accept_sec_context(OM_uint32 *minor,
 371                        gss_ctx_id_t *context_handle,
 372                        gss_cred_id_t cred,
 373                        gss_buffer_t input_token,
 374                        gss_channel_bindings_t input_chan_bindings,
 375                        gss_name_t *src_name,
 376                        gss_OID *mech_type,
 377                        gss_buffer_t output_token,
 378                        OM_uint32 *ret_flags,
 379                        OM_uint32 *time_rec,
 380                        gss_cred_id_t *delegated_cred_handle)
 381 {
 382     OM_uint32 major;
 383     OM_uint32 tmpMajor, tmpMinor;
 384     gss_ctx_id_t ctx = *context_handle;
 385     struct gss_eap_acceptor_sm *sm = NULL;
 386     gss_buffer_desc innerInputToken = GSS_C_EMPTY_BUFFER;
 387     gss_buffer_desc innerOutputToken = GSS_C_EMPTY_BUFFER;
 388
 389     *minor = 0;
 390
 391     output_token->length = 0;
 392     output_token->value = NULL;
 393
 394     if (cred != GSS_C_NO_CREDENTIAL && !(cred->flags & CRED_FLAG_ACCEPT)) {
 395         return GSS_S_NO_CRED;
 396     }
 397
 398     if (input_token == GSS_C_NO_BUFFER || input_token->length == 0) {
 399         return GSS_S_DEFECTIVE_TOKEN;
 400     }
 401
 402     if (ctx == GSS_C_NO_CONTEXT) {
 403         major = gssEapAllocContext(minor, &ctx);
 404         if (GSS_ERROR(major))
 405             return major;
 406
 407         *context_handle = ctx;
 408     }
 409
 410     GSSEAP_MUTEX_LOCK(&ctx->mutex);
 411
 412     sm = &eapGssAcceptorSm[ctx->state];
 413
 414     major = gssEapVerifyToken(minor, ctx, input_token,
 415                               sm->inputTokenType, &innerInputToken);
 416     if (GSS_ERROR(major))
 417         goto cleanup;
 418
 419     /* If credentials were provided, check they're usable with this mech */
 420     if (!gssEapCredAvailable(cred, ctx->mechanismUsed)) {
 421         major = GSS_S_BAD_MECH;
 422         goto cleanup;
 423     }
 424
 425     do {
 426         sm = &eapGssAcceptorSm[ctx->state];
 427
 428         major = (sm->processToken)(minor,
 429                                    ctx,
 430                                    cred,
 431                                    &innerInputToken,
 432                                    input_chan_bindings,
 433                                    &innerOutputToken);
 434         if (GSS_ERROR(major))
 435             goto cleanup;
 436     } while (major == GSS_S_CONTINUE_NEEDED && innerOutputToken.length == 0);
 437
 438     if (mech_type != NULL) {
 439         if (!gssEapInternalizeOid(ctx->mechanismUsed, mech_type))
 440             duplicateOid(&tmpMinor, ctx->mechanismUsed, mech_type);
 441     }
 442     if (innerOutputToken.length != 0) {
 443         tmpMajor = gssEapMakeToken(&tmpMinor, ctx, &innerOutputToken,
 444                                    sm->outputTokenType, output_token);
 445         if (GSS_ERROR(tmpMajor)) {
 446             major = tmpMajor;
 447             *minor = tmpMinor;
 448             goto cleanup;
 449         }
 450     }
 451     if (ret_flags != NULL)
 452         *ret_flags = ctx->gssFlags;
 453     if (delegated_cred_handle != NULL)
 454         *delegated_cred_handle = GSS_C_NO_CREDENTIAL;
 455
 456     if (major == GSS_S_COMPLETE) {
 457         if (src_name != NULL && ctx->initiatorName != GSS_C_NO_NAME) {
 458             major = gss_duplicate_name(&tmpMinor, ctx->initiatorName, src_name);
 459             if (GSS_ERROR(major))
 460                 goto cleanup;
 461         }
 462         if (time_rec != NULL)
 463             gss_context_time(&tmpMinor, ctx, time_rec);
 464     }
 465
 466     assert(ctx->state == EAP_STATE_ESTABLISHED || major == GSS_S_CONTINUE_NEEDED);
 467
 468 cleanup:
 469     GSSEAP_MUTEX_UNLOCK(&ctx->mutex);
 470
 471     if (GSS_ERROR(major))
 472         gssEapReleaseContext(&tmpMinor, context_handle);
 473
 474     gss_release_buffer(&tmpMinor, &innerOutputToken);
 475
 476     return major;
 477 }
 478