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, tmpMinor;
 160     gss_buffer_desc nameBuf;
 161     krb5_principal krbPrinc;
 162
 163     /* Awaits further specification */
 164     if (ctx->acceptorName == GSS_C_NO_NAME)
 165         return GSS_S_COMPLETE;
 166
 167     krbPrinc = ctx->acceptorName->krbPrincipal;
 168     assert(krbPrinc != NULL);
 169
 170     if (krbPrinc->length < 2)
 171         return GSS_S_BAD_NAME;
 172
 173     nameBuf.value = krbPrinc->data[0].data;
 174     nameBuf.length = krbPrinc->data[0].length;
 175
 176     major = addAvpFromBuffer(minor, ctx->acceptorCtx.radHandle, avps,
 177                              VENDOR_ATTR_GSS_ACCEPTOR_SERVICE_NAME,
 178                              VENDOR_ID_UKERNA,
 179                              &nameBuf);
 180     if (GSS_ERROR(major))
 181         return major;
 182
 183     nameBuf.value = krbPrinc->data[1].data;
 184     nameBuf.length = krbPrinc->data[2].length;
 185
 186     major = addAvpFromBuffer(minor, ctx->acceptorCtx.radHandle, avps,
 187                              VENDOR_ATTR_GSS_ACCEPTOR_HOST_NAME,
 188                              VENDOR_ID_UKERNA,
 189                              &nameBuf);
 190     if (GSS_ERROR(major))
 191         return major;
 192
 193     if (krbPrinc->realm.data != NULL) {
 194         nameBuf.value = krbPrinc->realm.data;
 195         nameBuf.length = krbPrinc->realm.length;
 196
 197         major = addAvpFromBuffer(minor, ctx->acceptorCtx.radHandle, avps,
 198                                  VENDOR_ATTR_GSS_ACCEPTOR_REALM_NAME,
 199                                  VENDOR_ID_UKERNA,
 200                                  &nameBuf);
 201         if (GSS_ERROR(major))
 202             return major;
 203     }
 204
 205     return GSS_S_COMPLETE;
 206 }
 207
 208 static OM_uint32
 209 eapGssSmAcceptAuthenticate(OM_uint32 *minor,
 210                            gss_ctx_id_t ctx,
 211                            gss_cred_id_t cred,
 212                            gss_buffer_t inputToken,
 213                            gss_channel_bindings_t chanBindings,
 214                            gss_buffer_t outputToken)
 215 {
 216     OM_uint32 major, tmpMinor;
 217     int code;
 218     VALUE_PAIR *send = NULL;
 219     VALUE_PAIR *received = NULL;
 220     rc_handle *rh = ctx->acceptorCtx.radHandle;
 221     char msgBuffer[4096];
 222     struct eap_hdr *pdu;
 223     unsigned char *pos;
 224     gss_buffer_desc nameBuf = GSS_C_EMPTY_BUFFER;
 225
 226     pdu = (struct eap_hdr *)inputToken->value;
 227     pos = (unsigned char *)(pdu + 1);
 228
 229     if (inputToken->length > sizeof(*pdu) &&
 230         pdu->code == EAP_CODE_RESPONSE &&
 231         pos[0] == EAP_TYPE_IDENTITY) {
 232         /*
 233          * XXX TODO do we really need to set User-Name? FreeRADIUS does
 234          * not appear to require it.
 235          */
 236         major = addAvpFromBuffer(minor, rh, &send, PW_USER_NAME, 0, &nameBuf);
 237         if (GSS_ERROR(major))
 238             goto cleanup;
 239
 240         major = setAcceptorIdentity(minor, ctx, &send);
 241         if (GSS_ERROR(major))
 242             goto cleanup;
 243     }
 244
 245     major = addAvpFromBuffer(minor, rh, &send, PW_EAP_MESSAGE, 0, inputToken);
 246     if (GSS_ERROR(major))
 247         goto cleanup;
 248
 249     if (ctx->acceptorCtx.lastStatus == CHALLENGE_RC) {
 250         major = addAvpFromBuffer(minor, rh, &send, PW_STATE, 0,
 251                                  &ctx->acceptorCtx.state);
 252         if (GSS_ERROR(major))
 253             goto cleanup;
 254
 255         gss_release_buffer(&tmpMinor, &ctx->acceptorCtx.state);
 256     }
 257
 258     code = rc_auth(rh, 0, send, &received, msgBuffer);
 259     switch (code) {
 260     case OK_RC:
 261     case CHALLENGE_RC:
 262         major = GSS_S_CONTINUE_NEEDED;
 263         break;
 264     case TIMEOUT_RC:
 265         major = GSS_S_UNAVAILABLE;
 266         break;
 267     case REJECT_RC:
 268         major = GSS_S_DEFECTIVE_CREDENTIAL;
 269         break;
 270     default:
 271         major = GSS_S_FAILURE;
 272         goto cleanup;
 273     }
 274
 275     if (GSS_ERROR(major))
 276         goto cleanup;
 277
 278     ctx->acceptorCtx.lastStatus = code;
 279
 280     major = getBufferFromAvps(minor, received, PW_EAP_MESSAGE, 0,
 281                               outputToken, TRUE);
 282     if ((major == GSS_S_UNAVAILABLE && code != OK_RC) ||
 283         GSS_ERROR(major))
 284         goto cleanup;
 285
 286     if (code == CHALLENGE_RC) {
 287         major = getBufferFromAvps(minor, received, PW_STATE, 0,
 288                                   &ctx->acceptorCtx.state, TRUE);
 289         if (major != GSS_S_UNAVAILABLE && GSS_ERROR(major))
 290             goto cleanup;
 291     } else {
 292         ctx->acceptorCtx.avps = received;
 293         received = NULL;
 294
 295         major = acceptReady(minor, ctx, cred);
 296         if (GSS_ERROR(major))
 297             goto cleanup;
 298
 299         ctx->state = EAP_STATE_GSS_CHANNEL_BINDINGS;
 300     }
 301
 302     major = GSS_S_CONTINUE_NEEDED;
 303
 304 cleanup:
 305     if (received != NULL)
 306         rc_avpair_free(received);
 307
 308     return major;
 309 }
 310
 311 static OM_uint32
 312 eapGssSmAcceptGssChannelBindings(OM_uint32 *minor,
 313                                  gss_ctx_id_t ctx,
 314                                  gss_cred_id_t cred,
 315                                  gss_buffer_t inputToken,
 316                                  gss_channel_bindings_t chanBindings,
 317                                  gss_buffer_t outputToken)
 318 {
 319     OM_uint32 major;
 320     gss_iov_buffer_desc iov[2];
 321
 322     outputToken->length = 0;
 323     outputToken->value = NULL;
 324
 325     if (chanBindings == GSS_C_NO_CHANNEL_BINDINGS) {
 326         ctx->state = EAP_STATE_ESTABLISHED;
 327         return GSS_S_COMPLETE;
 328     }
 329
 330     if (inputToken->length < 14) {
 331         return GSS_S_DEFECTIVE_TOKEN;
 332     }
 333
 334     iov[0].type = GSS_IOV_BUFFER_TYPE_DATA;
 335     iov[0].buffer.length = 0;
 336     iov[0].buffer.value = NULL;
 337
 338     if (chanBindings != GSS_C_NO_CHANNEL_BINDINGS)
 339         iov[0].buffer = chanBindings->application_data;
 340
 341     iov[1].type = GSS_IOV_BUFFER_TYPE_HEADER;
 342     iov[1].buffer.length = 16;
 343     iov[1].buffer.value = (unsigned char *)inputToken->value - 2;
 344
 345     assert(load_uint16_be(iov[1].buffer.value) == TOK_TYPE_GSS_CB);
 346
 347     iov[2].type = GSS_IOV_BUFFER_TYPE_TRAILER;
 348     iov[2].buffer.length = inputToken->length - 14;
 349     iov[2].buffer.value = (unsigned char *)inputToken->value + 14;
 350
 351     major = gssEapUnwrapOrVerifyMIC(minor, ctx, NULL, NULL,
 352                                     iov, 3, TOK_TYPE_GSS_CB);
 353     if (major == GSS_S_COMPLETE) {
 354         ctx->state = EAP_STATE_ESTABLISHED;
 355     }
 356
 357 #if 0
 358     gss_release_buffer(&tmpMinor, &iov[0].buffer);
 359 #endif
 360
 361     return major;
 362 }
 363
 364 static OM_uint32
 365 eapGssSmAcceptEstablished(OM_uint32 *minor,
 366                           gss_ctx_id_t ctx,
 367                           gss_cred_id_t cred,
 368                           gss_buffer_t inputToken,
 369                           gss_channel_bindings_t chanBindings,
 370                           gss_buffer_t outputToken)
 371 {
 372     /* Called with already established context */
 373     *minor = EINVAL;
 374     return GSS_S_BAD_STATUS;
 375 }
 376
 377 static struct gss_eap_acceptor_sm {
 378     enum gss_eap_token_type inputTokenType;
 379     enum gss_eap_token_type outputTokenType;
 380     OM_uint32 (*processToken)(OM_uint32 *,
 381                               gss_ctx_id_t,
 382                               gss_cred_id_t,
 383                               gss_buffer_t,
 384                               gss_channel_bindings_t,
 385                               gss_buffer_t);
 386 } eapGssAcceptorSm[] = {
 387     { TOK_TYPE_EAP_RESP,    TOK_TYPE_EAP_REQ,  eapGssSmAcceptIdentity           },
 388     { TOK_TYPE_EAP_RESP,    TOK_TYPE_EAP_REQ,  eapGssSmAcceptAuthenticate       },
 389     { TOK_TYPE_GSS_CB,      TOK_TYPE_NONE,     eapGssSmAcceptGssChannelBindings },
 390     { TOK_TYPE_NONE,        TOK_TYPE_NONE,     eapGssSmAcceptEstablished        },
 391 };
 392
 393 OM_uint32
 394 gss_accept_sec_context(OM_uint32 *minor,
 395                        gss_ctx_id_t *context_handle,
 396                        gss_cred_id_t cred,
 397                        gss_buffer_t input_token,
 398                        gss_channel_bindings_t input_chan_bindings,
 399                        gss_name_t *src_name,
 400                        gss_OID *mech_type,
 401                        gss_buffer_t output_token,
 402                        OM_uint32 *ret_flags,
 403                        OM_uint32 *time_rec,
 404                        gss_cred_id_t *delegated_cred_handle)
 405 {
 406     OM_uint32 major;
 407     OM_uint32 tmpMajor, tmpMinor;
 408     gss_ctx_id_t ctx = *context_handle;
 409     struct gss_eap_acceptor_sm *sm = NULL;
 410     gss_buffer_desc innerInputToken = GSS_C_EMPTY_BUFFER;
 411     gss_buffer_desc innerOutputToken = GSS_C_EMPTY_BUFFER;
 412
 413     *minor = 0;
 414
 415     output_token->length = 0;
 416     output_token->value = NULL;
 417
 418     if (cred != GSS_C_NO_CREDENTIAL && !(cred->flags & CRED_FLAG_ACCEPT)) {
 419         return GSS_S_NO_CRED;
 420     }
 421
 422     if (input_token == GSS_C_NO_BUFFER || input_token->length == 0) {
 423         return GSS_S_DEFECTIVE_TOKEN;
 424     }
 425
 426     if (ctx == GSS_C_NO_CONTEXT) {
 427         major = gssEapAllocContext(minor, &ctx);
 428         if (GSS_ERROR(major))
 429             return major;
 430
 431         *context_handle = ctx;
 432     }
 433
 434     GSSEAP_MUTEX_LOCK(&ctx->mutex);
 435
 436     sm = &eapGssAcceptorSm[ctx->state];
 437
 438     major = gssEapVerifyToken(minor, ctx, input_token,
 439                               sm->inputTokenType, &innerInputToken);
 440     if (GSS_ERROR(major))
 441         goto cleanup;
 442
 443     /* If credentials were provided, check they're usable with this mech */
 444     if (!gssEapCredAvailable(cred, ctx->mechanismUsed)) {
 445         major = GSS_S_BAD_MECH;
 446         goto cleanup;
 447     }
 448
 449     do {
 450         sm = &eapGssAcceptorSm[ctx->state];
 451
 452         major = (sm->processToken)(minor,
 453                                    ctx,
 454                                    cred,
 455                                    &innerInputToken,
 456                                    input_chan_bindings,
 457                                    &innerOutputToken);
 458         if (GSS_ERROR(major))
 459             goto cleanup;
 460     } while (major == GSS_S_CONTINUE_NEEDED && innerOutputToken.length == 0);
 461
 462     if (mech_type != NULL) {
 463         if (!gssEapInternalizeOid(ctx->mechanismUsed, mech_type))
 464             duplicateOid(&tmpMinor, ctx->mechanismUsed, mech_type);
 465     }
 466     if (innerOutputToken.length != 0) {
 467         tmpMajor = gssEapMakeToken(&tmpMinor, ctx, &innerOutputToken,
 468                                    sm->outputTokenType, output_token);
 469         if (GSS_ERROR(tmpMajor)) {
 470             major = tmpMajor;
 471             *minor = tmpMinor;
 472             goto cleanup;
 473         }
 474     }
 475     if (ret_flags != NULL)
 476         *ret_flags = ctx->gssFlags;
 477     if (delegated_cred_handle != NULL)
 478         *delegated_cred_handle = GSS_C_NO_CREDENTIAL;
 479
 480     if (major == GSS_S_COMPLETE) {
 481         if (src_name != NULL && ctx->initiatorName != GSS_C_NO_NAME) {
 482             major = gssEapDuplicateName(&tmpMinor, ctx->initiatorName, src_name);
 483             if (GSS_ERROR(major))
 484                 goto cleanup;
 485         }
 486         if (time_rec != NULL)
 487             gssEapContextTime(&tmpMinor, ctx, time_rec);
 488     }
 489
 490     assert(ctx->state == EAP_STATE_ESTABLISHED || major == GSS_S_CONTINUE_NEEDED);
 491
 492 cleanup:
 493     GSSEAP_MUTEX_UNLOCK(&ctx->mutex);
 494
 495     if (GSS_ERROR(major))
 496         gssEapReleaseContext(&tmpMinor, context_handle);
 497
 498     gss_release_buffer(&tmpMinor, &innerOutputToken);
 499
 500     return major;
 501 }
 502