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