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