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 {
  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     vp = rc_avpair_get(ctx->acceptorCtx.avps, PW_MSCHAP2_SUCCESS, 0);
  67     if (ctx->encryptionType != ENCTYPE_NULL && vp != NULL) {
  68         major = gssEapDeriveRfc3961Key(minor,
  69                                        (unsigned char *)vp->strvalue,
  70                                        vp->lvalue,
  71                                        ctx->encryptionType,
  72                                        &ctx->rfc3961Key);
  73         if (GSS_ERROR(major))
  74             return major;
  75
  76         major = rfc3961ChecksumTypeForKey(minor, &ctx->rfc3961Key,
  77                                            &ctx->checksumType);
  78         if (GSS_ERROR(major))
  79             return major;
  80     } else {
  81         /*
  82          * draft-howlett-eap-gss says that integrity/confidentialty should
  83          * always be advertised as available, but if we have no keying
  84          * material it seems confusing to the caller to advertise this.
  85          */
  86         ctx->gssFlags &= ~(GSS_C_INTEG_FLAG | GSS_C_CONF_FLAG);
  87     }
  88
  89     major = sequenceInit(minor,
  90                          &ctx->seqState, ctx->recvSeq,
  91                          ((ctx->gssFlags & GSS_C_REPLAY_FLAG) != 0),
  92                          ((ctx->gssFlags & GSS_C_SEQUENCE_FLAG) != 0),
  93                          TRUE);
  94     if (GSS_ERROR(major))
  95         return major;
  96
  97     return GSS_S_COMPLETE;
  98 }
  99
 100 static OM_uint32
 101 eapGssSmAcceptIdentity(OM_uint32 *minor,
 102                        gss_ctx_id_t ctx,
 103                        gss_cred_id_t cred,
 104                        gss_buffer_t inputToken,
 105                        gss_channel_bindings_t chanBindings,
 106                        gss_buffer_t outputToken)
 107 {
 108     OM_uint32 major;
 109     rc_handle *rh;
 110     union {
 111         struct eap_hdr eap;
 112         unsigned char data[5];
 113     } pdu;
 114     gss_buffer_desc pduBuffer;
 115     char *config = RC_CONFIG_FILE;
 116
 117     if (inputToken != GSS_C_NO_BUFFER && inputToken->length != 0)
 118         return GSS_S_DEFECTIVE_TOKEN;
 119
 120     assert(ctx->acceptorCtx.radHandle == NULL);
 121
 122     if (cred != GSS_C_NO_CREDENTIAL && cred->radiusConfigFile != NULL)
 123         config = cred->radiusConfigFile;
 124
 125     rh = ctx->acceptorCtx.radHandle = rc_read_config(config);
 126     if (rh == NULL) {
 127         *minor = errno;
 128         return GSS_S_FAILURE;
 129     }
 130
 131     if (rc_read_dictionary(rh, rc_conf_str(rh, "dictionary")) != 0) {
 132         *minor = errno;
 133         return GSS_S_FAILURE;
 134     }
 135
 136     if (ctx->acceptorName == GSS_C_NO_NAME &&
 137         cred != GSS_C_NO_CREDENTIAL &&
 138         cred->name != GSS_C_NO_NAME) {
 139         major = gss_duplicate_name(minor, cred->name, &ctx->acceptorName);
 140         if (GSS_ERROR(major))
 141             return major;
 142     }
 143
 144     pdu.eap.code = EAP_CODE_REQUEST;
 145     pdu.eap.identifier = 0;
 146     pdu.eap.length = htons(sizeof(pdu.data));
 147     pdu.data[4] = EAP_TYPE_IDENTITY;
 148
 149     pduBuffer.length = sizeof(pdu.data);
 150     pduBuffer.value = pdu.data;
 151
 152     major = duplicateBuffer(minor, &pduBuffer, outputToken);
 153     if (GSS_ERROR(major))
 154         return major;
 155
 156     ctx->state = EAP_STATE_AUTHENTICATE;
 157
 158     return GSS_S_CONTINUE_NEEDED;
 159 }
 160
 161 static OM_uint32
 162 eapGssSmAcceptAuthenticate(OM_uint32 *minor,
 163                            gss_ctx_id_t ctx,
 164                            gss_cred_id_t cred,
 165                            gss_buffer_t inputToken,
 166                            gss_channel_bindings_t chanBindings,
 167                            gss_buffer_t outputToken)
 168 {
 169     OM_uint32 major;
 170     OM_uint32 service = PW_AUTHENTICATE_ONLY;
 171     int code;
 172     VALUE_PAIR *send = NULL;
 173     VALUE_PAIR *received = NULL;
 174     rc_handle *rh = ctx->acceptorCtx.radHandle;
 175     char msgBuffer[4096];
 176
 177     if (rc_avpair_add(rh, &send, PW_EAP_MESSAGE,
 178                       inputToken->value, inputToken->length, 0) == NULL) {
 179         *minor = ENOMEM;
 180         major = GSS_S_FAILURE;
 181         goto cleanup;
 182     }
 183
 184     if (rc_avpair_add(rh, &send, PW_SERVICE_TYPE, &service, -1, 0) == NULL) {
 185         *minor = ENOMEM;
 186         major = GSS_S_FAILURE;
 187         goto cleanup;
 188     }
 189
 190     code = rc_auth(rh, 0, send, &received, msgBuffer);
 191     if (code != 0) {
 192         *minor = errno;
 193         major = GSS_S_UNAVAILABLE;
 194         goto cleanup;
 195     }
 196
 197     if (code == OK_RC || code == PW_ACCESS_CHALLENGE) {
 198         VALUE_PAIR *eapResponse;
 199         gss_buffer_desc eapBuf = GSS_C_EMPTY_BUFFER;
 200
 201         eapResponse = rc_avpair_get(received, PW_EAP_MESSAGE, 0);
 202         if (eapResponse != NULL) {
 203             eapBuf.length = eapResponse->lvalue;
 204             eapBuf.value = eapResponse->strvalue;
 205         }
 206
 207         major = duplicateBuffer(minor, &eapBuf, outputToken);
 208         if (GSS_ERROR(major))
 209             goto cleanup;
 210
 211         major = GSS_S_CONTINUE_NEEDED;
 212     } else {
 213         major = GSS_S_FAILURE;
 214         goto cleanup;
 215     }
 216
 217     if (code == OK_RC) {
 218         ctx->acceptorCtx.avps = received;
 219         received = NULL;
 220
 221         major = acceptReady(minor, ctx);
 222         if (GSS_ERROR(major))
 223             goto cleanup;
 224
 225         ctx->state = EAP_STATE_GSS_CHANNEL_BINDINGS;
 226         major = GSS_S_CONTINUE_NEEDED;
 227     }
 228
 229 cleanup:
 230     if (received != NULL)
 231         rc_avpair_free(received);
 232
 233     return major;
 234 }
 235
 236 static OM_uint32
 237 eapGssSmAcceptGssChannelBindings(OM_uint32 *minor,
 238                                  gss_ctx_id_t ctx,
 239                                  gss_cred_id_t cred,
 240                                  gss_buffer_t inputToken,
 241                                  gss_channel_bindings_t chanBindings,
 242                                  gss_buffer_t outputToken)
 243 {
 244     OM_uint32 major;
 245     gss_iov_buffer_desc iov[2];
 246
 247     outputToken->length = 0;
 248     outputToken->value = NULL;
 249
 250     if (chanBindings == GSS_C_NO_CHANNEL_BINDINGS) {
 251         ctx->state = EAP_STATE_ESTABLISHED;
 252         return GSS_S_COMPLETE;
 253     }
 254
 255     if (inputToken->length < 14) {
 256         return GSS_S_DEFECTIVE_TOKEN;
 257     }
 258
 259     iov[0].type = GSS_IOV_BUFFER_TYPE_DATA;
 260     iov[0].buffer.length = 0;
 261     iov[0].buffer.value = NULL;
 262
 263     if (chanBindings != GSS_C_NO_CHANNEL_BINDINGS)
 264         iov[0].buffer = chanBindings->application_data;
 265
 266     iov[1].type = GSS_IOV_BUFFER_TYPE_HEADER;
 267     iov[1].buffer.length = 16;
 268     iov[1].buffer.value = (unsigned char *)inputToken->value - 2;
 269
 270     assert(load_uint16_be(iov[1].buffer.value) == TOK_TYPE_GSS_CB);
 271
 272     iov[2].type = GSS_IOV_BUFFER_TYPE_TRAILER;
 273     iov[2].buffer.length = inputToken->length - 14;
 274     iov[2].buffer.value = (unsigned char *)inputToken->value + 14;
 275
 276     major = gssEapUnwrapOrVerifyMIC(minor, ctx, NULL, NULL,
 277                                     iov, 3, TOK_TYPE_GSS_CB);
 278     if (major == GSS_S_COMPLETE) {
 279         ctx->state = EAP_STATE_ESTABLISHED;
 280     }
 281
 282 #if 0
 283     gss_release_buffer(&tmpMinor, &iov[0].buffer);
 284 #endif
 285
 286     return major;
 287 }
 288
 289 static OM_uint32
 290 eapGssSmAcceptEstablished(OM_uint32 *minor,
 291                           gss_ctx_id_t ctx,
 292                           gss_cred_id_t cred,
 293                           gss_buffer_t inputToken,
 294                           gss_channel_bindings_t chanBindings,
 295                           gss_buffer_t outputToken)
 296 {
 297     /* Called with already established context */
 298     *minor = EINVAL;
 299     return GSS_S_BAD_STATUS;
 300 }
 301
 302 static struct gss_eap_acceptor_sm {
 303     enum gss_eap_token_type inputTokenType;
 304     enum gss_eap_token_type outputTokenType;
 305     OM_uint32 (*processToken)(OM_uint32 *,
 306                               gss_ctx_id_t,
 307                               gss_cred_id_t,
 308                               gss_buffer_t,
 309                               gss_channel_bindings_t,
 310                               gss_buffer_t);
 311 } eapGssAcceptorSm[] = {
 312     { TOK_TYPE_EAP_RESP,    TOK_TYPE_EAP_REQ,  eapGssSmAcceptIdentity           },
 313     { TOK_TYPE_EAP_RESP,    TOK_TYPE_EAP_REQ,  eapGssSmAcceptAuthenticate       },
 314     { TOK_TYPE_GSS_CB,      TOK_TYPE_NONE,     eapGssSmAcceptGssChannelBindings },
 315     { TOK_TYPE_NONE,        TOK_TYPE_NONE,     eapGssSmAcceptEstablished        },
 316 };
 317
 318 OM_uint32
 319 gss_accept_sec_context(OM_uint32 *minor,
 320                        gss_ctx_id_t *context_handle,
 321                        gss_cred_id_t cred,
 322                        gss_buffer_t input_token,
 323                        gss_channel_bindings_t input_chan_bindings,
 324                        gss_name_t *src_name,
 325                        gss_OID *mech_type,
 326                        gss_buffer_t output_token,
 327                        OM_uint32 *ret_flags,
 328                        OM_uint32 *time_rec,
 329                        gss_cred_id_t *delegated_cred_handle)
 330 {
 331     OM_uint32 major;
 332     OM_uint32 tmpMajor, tmpMinor;
 333     gss_ctx_id_t ctx = *context_handle;
 334     struct gss_eap_acceptor_sm *sm = NULL;
 335     gss_buffer_desc innerInputToken = GSS_C_EMPTY_BUFFER;
 336     gss_buffer_desc innerOutputToken = GSS_C_EMPTY_BUFFER;
 337
 338     *minor = 0;
 339
 340     output_token->length = 0;
 341     output_token->value = NULL;
 342
 343     if (cred != GSS_C_NO_CREDENTIAL && !(cred->flags & CRED_FLAG_ACCEPT)) {
 344         return GSS_S_NO_CRED;
 345     }
 346
 347     if (input_token == GSS_C_NO_BUFFER || input_token->length == 0) {
 348         return GSS_S_DEFECTIVE_TOKEN;
 349     }
 350
 351     if (ctx == GSS_C_NO_CONTEXT) {
 352         major = gssEapAllocContext(minor, &ctx);
 353         if (GSS_ERROR(major))
 354             return major;
 355
 356         *context_handle = ctx;
 357     }
 358
 359     GSSEAP_MUTEX_LOCK(&ctx->mutex);
 360
 361     sm = &eapGssAcceptorSm[ctx->state];
 362
 363     major = gssEapVerifyToken(minor, ctx, input_token,
 364                               sm->inputTokenType, &innerInputToken);
 365     if (GSS_ERROR(major))
 366         goto cleanup;
 367
 368     /* If credentials were provided, check they're usable with this mech */
 369     if (!gssEapCredAvailable(cred, ctx->mechanismUsed)) {
 370         major = GSS_S_BAD_MECH;
 371         goto cleanup;
 372     }
 373
 374     do {
 375         sm = &eapGssAcceptorSm[ctx->state];
 376
 377         major = (sm->processToken)(minor,
 378                                    ctx,
 379                                    cred,
 380                                    &innerInputToken,
 381                                    input_chan_bindings,
 382                                    &innerOutputToken);
 383         if (GSS_ERROR(major))
 384             goto cleanup;
 385     } while (major == GSS_S_CONTINUE_NEEDED && innerOutputToken.length == 0);
 386
 387     if (mech_type != NULL) {
 388         if (!gssEapInternalizeOid(ctx->mechanismUsed, mech_type))
 389             duplicateOid(&tmpMinor, ctx->mechanismUsed, mech_type);
 390     }
 391     if (innerOutputToken.length != 0) {
 392         tmpMajor = gssEapMakeToken(&tmpMinor, ctx, &innerOutputToken,
 393                                    sm->outputTokenType, output_token);
 394         if (GSS_ERROR(tmpMajor)) {
 395             major = tmpMajor;
 396             *minor = tmpMinor;
 397             goto cleanup;
 398         }
 399     }
 400     if (ret_flags != NULL)
 401         *ret_flags = ctx->gssFlags;
 402     if (delegated_cred_handle != NULL)
 403         *delegated_cred_handle = GSS_C_NO_CREDENTIAL;
 404
 405     if (major == GSS_S_COMPLETE) {
 406         if (src_name != NULL && ctx->initiatorName != GSS_C_NO_NAME) {
 407             major = gss_duplicate_name(&tmpMinor, ctx->initiatorName, src_name);
 408             if (GSS_ERROR(major))
 409                 goto cleanup;
 410         }
 411         if (time_rec != NULL)
 412             gss_context_time(&tmpMinor, ctx, time_rec);
 413     }
 414
 415     assert(ctx->state == EAP_STATE_ESTABLISHED || major == GSS_S_CONTINUE_NEEDED);
 416
 417 cleanup:
 418     GSSEAP_MUTEX_UNLOCK(&ctx->mutex);
 419
 420     if (GSS_ERROR(major))
 421         gssEapReleaseContext(&tmpMinor, context_handle);
 422
 423     gss_release_buffer(&tmpMinor, &innerOutputToken);
 424
 425     return major;
 426 }
 427