5fcbec8c573ee3528b26b3d0cb765189e5941eeb
[mech_eap.git] / init_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 static OM_uint32
36 policyVariableToFlag(enum eapol_bool_var variable)
37 {
38     OM_uint32 flag = 0;
39
40     switch (variable) {
41     case EAPOL_eapSuccess:
42         flag = CTX_FLAG_EAP_SUCCESS;
43         break;
44     case EAPOL_eapRestart:
45         flag = CTX_FLAG_EAP_RESTART;
46         break;
47     case EAPOL_eapFail:
48         flag = CTX_FLAG_EAP_FAIL;
49         break;
50     case EAPOL_eapResp:
51         flag = CTX_FLAG_EAP_RESP;
52         break;
53     case EAPOL_eapNoResp:
54         flag = CTX_FLAG_EAP_NO_RESP;
55         break;
56     case EAPOL_eapReq:
57         flag = CTX_FLAG_EAP_REQ;
58         break;
59     case EAPOL_portEnabled:
60         flag = CTX_FLAG_EAP_PORT_ENABLED;
61         break;
62     case EAPOL_altAccept:
63         flag = CTX_FLAG_EAP_ALT_ACCEPT;
64         break;
65     case EAPOL_altReject:
66         flag = CTX_FLAG_EAP_ALT_REJECT;
67         break;
68     }
69
70     return flag;
71 }
72
73 static struct eap_peer_config *
74 peerGetConfig(void *ctx)
75 {
76     gss_ctx_id_t gssCtx = (gss_ctx_id_t)ctx;
77
78     return &gssCtx->initiatorCtx.eapPeerConfig;
79 }
80
81 static Boolean
82 peerGetBool(void *data, enum eapol_bool_var variable)
83 {
84     gss_ctx_id_t ctx = data;
85     OM_uint32 flag;
86
87     if (ctx == GSS_C_NO_CONTEXT)
88         return FALSE;
89
90     flag = policyVariableToFlag(variable);
91
92     return ((ctx->flags & flag) != 0);
93 }
94
95 static void
96 peerSetBool(void *data, enum eapol_bool_var variable,
97             Boolean value)
98 {
99     gss_ctx_id_t ctx = data;
100     OM_uint32 flag;
101
102     if (ctx == GSS_C_NO_CONTEXT)
103         return;
104
105     flag = policyVariableToFlag(variable);
106
107     if (value)
108         ctx->flags |= flag;
109     else
110         ctx->flags &= ~(flag);
111 }
112
113 static unsigned int
114 peerGetInt(void *data, enum eapol_int_var variable)
115 {
116     gss_ctx_id_t ctx = data;
117
118     if (ctx == GSS_C_NO_CONTEXT)
119         return FALSE;
120
121     assert(CTX_IS_INITIATOR(ctx));
122
123     switch (variable) {
124     case EAPOL_idleWhile:
125         return ctx->initiatorCtx.idleWhile;
126         break;
127     }
128
129     return 0;
130 }
131
132 static void
133 peerSetInt(void *data, enum eapol_int_var variable,
134            unsigned int value)
135 {
136     gss_ctx_id_t ctx = data;
137
138     if (ctx == GSS_C_NO_CONTEXT)
139         return;
140
141     assert(CTX_IS_INITIATOR(ctx));
142
143     switch (variable) {
144     case EAPOL_idleWhile:
145         ctx->initiatorCtx.idleWhile = value;
146         break;
147     }
148 }
149
150 static struct wpabuf *
151 peerGetEapReqData(void *ctx)
152 {
153     gss_ctx_id_t gssCtx = (gss_ctx_id_t)ctx;
154
155     return &gssCtx->initiatorCtx.reqData;
156 }
157
158 static void
159 peerSetConfigBlob(void *ctx, struct wpa_config_blob *blob)
160 {
161 }
162
163 static const struct wpa_config_blob *
164 peerGetConfigBlob(void *ctx, const char *name)
165 {
166     return NULL;
167 }
168
169 static void
170 peerNotifyPending(void *ctx)
171 {
172 }
173
174 static struct eapol_callbacks gssEapPolicyCallbacks = {
175     peerGetConfig,
176     peerGetBool,
177     peerSetBool,
178     peerGetInt,
179     peerSetInt,
180     peerGetEapReqData,
181     peerSetConfigBlob,
182     peerGetConfigBlob,
183     peerNotifyPending,
184 };
185
186 extern int wpa_debug_level;
187
188 static OM_uint32
189 peerConfigInit(OM_uint32 *minor,
190                gss_cred_id_t cred,
191                gss_ctx_id_t ctx)
192 {
193     krb5_context krbContext;
194     struct eap_peer_config *eapPeerConfig = &ctx->initiatorCtx.eapPeerConfig;
195     krb5_error_code code;
196     char *identity;
197
198     GSSEAP_KRB_INIT(&krbContext);
199
200     eapPeerConfig->fragment_size = 1024;
201     wpa_debug_level = 0;
202
203     code = krb5_unparse_name(krbContext, cred->name->krbPrincipal, &identity);
204     if (code != 0) {
205         *minor = code;
206         return GSS_S_FAILURE;
207     }
208
209     eapPeerConfig->identity = (unsigned char *)identity;
210     eapPeerConfig->identity_len = strlen(identity);
211     eapPeerConfig->password = (unsigned char *)cred->password.value;
212     eapPeerConfig->password_len = cred->password.length;
213
214     return GSS_S_COMPLETE;
215 }
216
217 static OM_uint32
218 peerConfigFree(OM_uint32 *minor,
219                gss_ctx_id_t ctx)
220 {
221     krb5_context krbContext;
222     struct eap_peer_config *eapPeerConfig = &ctx->initiatorCtx.eapPeerConfig;
223
224     GSSEAP_KRB_INIT(&krbContext);
225
226     krb5_free_unparsed_name(krbContext, (char *)eapPeerConfig->identity);
227
228     return GSS_S_COMPLETE;
229 }
230
231 static OM_uint32
232 initReady(OM_uint32 *minor, gss_ctx_id_t ctx)
233 {
234     OM_uint32 major;
235     const unsigned char *key;
236     size_t keyLength;
237     krb5_enctype encryptionType;
238     int gotKey = 0;
239
240     /* Cache encryption type derived from selected mechanism OID */
241     major = gssEapOidToEnctype(minor, ctx->mechanismUsed, &encryptionType);
242     if (GSS_ERROR(major))
243         return major;
244
245     if (encryptionType != ENCTYPE_NULL &&
246         eap_key_available(ctx->initiatorCtx.eap)) {
247         key = eap_get_eapKeyData(ctx->initiatorCtx.eap, &keyLength);
248
249         if (keyLength >= EAP_EMSK_LEN) {
250             major = gssEapDeriveRfc3961Key(minor,
251                                            &key[EAP_EMSK_LEN / 2],
252                                            EAP_EMSK_LEN / 2,
253                                            encryptionType,
254                                            &ctx->rfc3961Key);
255                if (GSS_ERROR(major))
256                    return major;
257
258             major = rfc3961ChecksumTypeForKey(minor, &ctx->rfc3961Key,
259                                               &ctx->checksumType);
260             if (GSS_ERROR(major))
261                 return major;
262             gotKey++;
263         }
264     }
265
266     if (gotKey) {
267         ctx->encryptionType = encryptionType;
268     } else {
269         /*
270          * draft-howlett-eap-gss says that integrity/confidentialty should
271          * always be advertised as available, but if we have no keying
272          * material it seems confusing to the caller to advertise this.
273          */
274         ctx->gssFlags &= ~(GSS_C_INTEG_FLAG | GSS_C_CONF_FLAG);
275     }
276
277     major = sequenceInit(minor,
278                          &ctx->seqState,
279                          ctx->recvSeq,
280                          ((ctx->gssFlags & GSS_C_REPLAY_FLAG) != 0),
281                          ((ctx->gssFlags & GSS_C_SEQUENCE_FLAG) != 0),
282                          TRUE);
283     if (GSS_ERROR(major))
284         return major;
285
286     return GSS_S_COMPLETE;
287 }
288
289 static OM_uint32
290 eapGssSmInitIdentity(OM_uint32 *minor,
291                      gss_cred_id_t cred,
292                      gss_ctx_id_t ctx,
293                      gss_name_t target,
294                      gss_OID mech,
295                      OM_uint32 reqFlags,
296                      OM_uint32 timeReq,
297                      gss_channel_bindings_t chanBindings,
298                      gss_buffer_t inputToken,
299                      gss_buffer_t outputToken)
300 {
301     time_t now;
302     OM_uint32 major;
303     int initialContextToken;
304
305     initialContextToken = (inputToken == GSS_C_NO_BUFFER ||
306                            inputToken->length == 0);
307     if (!initialContextToken)
308         return GSS_S_DEFECTIVE_TOKEN;
309
310     time(&now);
311     if (timeReq == 0 || timeReq == GSS_C_INDEFINITE)
312         ctx->expiryTime = 0;
313     else
314         ctx->expiryTime = now + timeReq;
315
316     major = gssEapDuplicateName(minor, cred->name, &ctx->initiatorName);
317     if (GSS_ERROR(major))
318         return major;
319
320     major = gssEapDuplicateName(minor, target, &ctx->acceptorName);
321     if (GSS_ERROR(major))
322         return major;
323
324     if (mech == GSS_C_NULL_OID || oidEqual(mech, GSS_EAP_MECHANISM)) {
325         major = gssEapDefaultMech(minor, &ctx->mechanismUsed);
326     } else if (gssEapIsConcreteMechanismOid(mech)) {
327         if (!gssEapInternalizeOid(mech, &ctx->mechanismUsed))
328             major = duplicateOid(minor, mech, &ctx->mechanismUsed);
329     } else {
330         major = GSS_S_BAD_MECH;
331     }
332     if (GSS_ERROR(major))
333         return major;
334
335     /* If credentials were provided, check they're usable with this mech */
336     if (!gssEapCredAvailable(cred, ctx->mechanismUsed))
337         return GSS_S_BAD_MECH;
338
339     ctx->state = EAP_STATE_AUTHENTICATE;
340
341     return GSS_S_CONTINUE_NEEDED;
342 }
343
344 static struct wpabuf emptyWpaBuffer;
345
346 static OM_uint32
347 eapGssSmInitAuthenticate(OM_uint32 *minor,
348                          gss_cred_id_t cred,
349                          gss_ctx_id_t ctx,
350                          gss_name_t target,
351                          gss_OID mech,
352                          OM_uint32 reqFlags,
353                          OM_uint32 timeReq,
354                          gss_channel_bindings_t chanBindings,
355                          gss_buffer_t inputToken,
356                          gss_buffer_t outputToken)
357 {
358     OM_uint32 major;
359     OM_uint32 tmpMinor;
360     int code;
361     struct wpabuf *resp = NULL;
362     int initialContextToken;
363
364     initialContextToken = (inputToken == GSS_C_NO_BUFFER ||
365                            inputToken->length == 0);
366
367     major = peerConfigInit(minor, cred, ctx);
368     if (GSS_ERROR(major))
369         goto cleanup;
370
371     if (ctx->initiatorCtx.eap == NULL) {
372         struct eap_config eapConfig;
373
374         memset(&eapConfig, 0, sizeof(eapConfig));
375
376         ctx->initiatorCtx.eap = eap_peer_sm_init(ctx,
377                                                  &gssEapPolicyCallbacks,
378                                                  ctx,
379                                                  &eapConfig);
380         if (ctx->initiatorCtx.eap == NULL) {
381             major = GSS_S_FAILURE;
382             goto cleanup;
383         }
384
385         ctx->flags |= CTX_FLAG_EAP_RESTART | CTX_FLAG_EAP_PORT_ENABLED;
386     }
387
388     ctx->flags |= CTX_FLAG_EAP_REQ; /* we have a Request from the acceptor */
389
390     wpabuf_set(&ctx->initiatorCtx.reqData,
391                inputToken->value, inputToken->length);
392
393     major = GSS_S_CONTINUE_NEEDED;
394
395     code = eap_peer_sm_step(ctx->initiatorCtx.eap);
396     if (ctx->flags & CTX_FLAG_EAP_RESP) {
397         ctx->flags &= ~(CTX_FLAG_EAP_RESP);
398
399         resp = eap_get_eapRespData(ctx->initiatorCtx.eap);
400     } else if (ctx->flags & CTX_FLAG_EAP_SUCCESS) {
401         major = initReady(minor, ctx);
402         if (GSS_ERROR(major))
403             goto cleanup;
404
405         ctx->flags &= ~(CTX_FLAG_EAP_SUCCESS);
406         major = GSS_S_CONTINUE_NEEDED;
407         ctx->state = EAP_STATE_GSS_CHANNEL_BINDINGS;
408     } else if (ctx->flags & CTX_FLAG_EAP_FAIL) {
409         major = GSS_S_DEFECTIVE_CREDENTIAL;
410     } else if (code == 0 && initialContextToken) {
411         resp = &emptyWpaBuffer;
412         major = GSS_S_CONTINUE_NEEDED;
413     } else {
414         major = GSS_S_DEFECTIVE_TOKEN;
415     }
416
417 cleanup:
418     if (resp != NULL) {
419         OM_uint32 tmpMajor;
420         gss_buffer_desc respBuf;
421
422         assert(major == GSS_S_CONTINUE_NEEDED);
423
424         respBuf.length = wpabuf_len(resp);
425         respBuf.value = (void *)wpabuf_head(resp);
426
427         tmpMajor = duplicateBuffer(&tmpMinor, &respBuf, outputToken);
428         if (GSS_ERROR(tmpMajor)) {
429             major = tmpMajor;
430             *minor = tmpMinor;
431         }
432     }
433
434     wpabuf_set(&ctx->initiatorCtx.reqData, NULL, 0);
435     peerConfigFree(&tmpMinor, ctx);
436
437     return major;
438 }
439
440 static OM_uint32
441 eapGssSmInitGssChannelBindings(OM_uint32 *minor,
442                                gss_cred_id_t cred,
443                                gss_ctx_id_t ctx,
444                                gss_name_t target,
445                                gss_OID mech,
446                                OM_uint32 reqFlags,
447                                OM_uint32 timeReq,
448                                gss_channel_bindings_t chanBindings,
449                                gss_buffer_t inputToken,
450                                gss_buffer_t outputToken)
451 {
452     OM_uint32 major;
453     gss_iov_buffer_desc iov[2];
454     gss_buffer_desc buf;
455
456     iov[0].type = GSS_IOV_BUFFER_TYPE_DATA;
457     iov[0].buffer.length = 0;
458     iov[0].buffer.value = NULL;
459
460     iov[1].type = GSS_IOV_BUFFER_TYPE_HEADER | GSS_IOV_BUFFER_FLAG_ALLOCATE;
461     iov[1].buffer.length = 0;
462     iov[1].buffer.value = NULL;
463
464     if (chanBindings != GSS_C_NO_CHANNEL_BINDINGS)
465         iov[0].buffer = chanBindings->application_data;
466
467     major = gssEapWrapOrGetMIC(minor, ctx, FALSE, FALSE, iov, 2,
468                                TOK_TYPE_GSS_CB);
469     if (GSS_ERROR(major))
470         goto cleanup;
471
472     /* Skip past token ID */
473     assert(iov[1].buffer.length > 2);
474     assert(load_uint16_be(iov[1].buffer.value) == TOK_TYPE_GSS_CB);
475
476     buf.length = iov[1].buffer.length - 2;
477     buf.value = (unsigned char *)iov[1].buffer.value + 2;
478
479     major = duplicateBuffer(minor, &buf, outputToken);
480     if (GSS_ERROR(major))
481         goto cleanup;
482
483     major = GSS_S_COMPLETE;
484     ctx->state = EAP_STATE_ESTABLISHED;
485
486 cleanup:
487     gssEapReleaseIov(iov, 2);
488
489     return major;
490 }
491
492 static OM_uint32
493 eapGssSmInitEstablished(OM_uint32 *minor,
494                         gss_cred_id_t cred,
495                         gss_ctx_id_t ctx,
496                         gss_name_t target,
497                         gss_OID mech,
498                         OM_uint32 reqFlags,
499                         OM_uint32 timeReq,
500                         gss_channel_bindings_t chanBindings,
501                         gss_buffer_t inputToken,
502                         gss_buffer_t outputToken)
503 {
504     /* Called with already established context */
505     *minor = EINVAL;
506     return GSS_S_BAD_STATUS;
507 }
508
509 static struct gss_eap_initiator_sm {
510     enum gss_eap_token_type inputTokenType;
511     enum gss_eap_token_type outputTokenType;
512     OM_uint32 (*processToken)(OM_uint32 *,
513                               gss_cred_id_t,
514                               gss_ctx_id_t,
515                               gss_name_t,
516                               gss_OID,
517                               OM_uint32,
518                               OM_uint32,
519                               gss_channel_bindings_t,
520                               gss_buffer_t,
521                               gss_buffer_t);
522 } eapGssInitiatorSm[] = {
523     { TOK_TYPE_NONE,    TOK_TYPE_EAP_RESP,  eapGssSmInitIdentity            },
524     { TOK_TYPE_EAP_REQ, TOK_TYPE_EAP_RESP,  eapGssSmInitAuthenticate        },
525     { TOK_TYPE_NONE,    TOK_TYPE_GSS_CB,    eapGssSmInitGssChannelBindings  },
526     { TOK_TYPE_NONE,    TOK_TYPE_NONE,      eapGssSmInitEstablished         },
527 };
528
529 OM_uint32
530 gss_init_sec_context(OM_uint32 *minor,
531                      gss_cred_id_t cred,
532                      gss_ctx_id_t *context_handle,
533                      gss_name_t target_name,
534                      gss_OID mech_type,
535                      OM_uint32 req_flags,
536                      OM_uint32 time_req,
537                      gss_channel_bindings_t input_chan_bindings,
538                      gss_buffer_t input_token,
539                      gss_OID *actual_mech_type,
540                      gss_buffer_t output_token,
541                      OM_uint32 *ret_flags,
542                      OM_uint32 *time_rec)
543 {
544     OM_uint32 major;
545     OM_uint32 tmpMajor, tmpMinor;
546     gss_ctx_id_t ctx = *context_handle;
547     struct gss_eap_initiator_sm *sm = NULL;
548     gss_buffer_desc innerInputToken;
549     gss_buffer_desc innerOutputToken = GSS_C_EMPTY_BUFFER;
550
551     *minor = 0;
552
553     output_token->length = 0;
554     output_token->value = NULL;
555
556     if (cred != GSS_C_NO_CREDENTIAL && !(cred->flags & CRED_FLAG_INITIATE)) {
557         return GSS_S_NO_CRED;
558     }
559
560     if (ctx == GSS_C_NO_CONTEXT) {
561         if (input_token != GSS_C_NO_BUFFER && input_token->length != 0) {
562             return GSS_S_DEFECTIVE_TOKEN;
563         }
564
565         major = gssEapAllocContext(minor, &ctx);
566         if (GSS_ERROR(major))
567             return major;
568
569         ctx->flags |= CTX_FLAG_INITIATOR;
570
571         *context_handle = ctx;
572     }
573
574     GSSEAP_MUTEX_LOCK(&ctx->mutex);
575
576     sm = &eapGssInitiatorSm[ctx->state];
577
578     if (input_token != GSS_C_NO_BUFFER) {
579         major = gssEapVerifyToken(minor, ctx, input_token,
580                                   sm->inputTokenType, &innerInputToken);
581         if (GSS_ERROR(major))
582             goto cleanup;
583     } else {
584         innerInputToken.length = 0;
585         innerInputToken.value = NULL;
586     }
587
588     /*
589      * Advance through state machine whilst empty tokens are emitted and
590      * the status is not GSS_S_COMPLETE or an error status.
591      */
592     do {
593         sm = &eapGssInitiatorSm[ctx->state];
594
595         major = (sm->processToken)(minor,
596                                    cred,
597                                    ctx,
598                                    target_name,
599                                    mech_type,
600                                    req_flags,
601                                    time_req,
602                                    input_chan_bindings,
603                                    &innerInputToken,
604                                    &innerOutputToken);
605         if (GSS_ERROR(major))
606             goto cleanup;
607     } while (major == GSS_S_CONTINUE_NEEDED && innerOutputToken.value == NULL);
608
609     if (actual_mech_type != NULL) {
610         if (!gssEapInternalizeOid(ctx->mechanismUsed, actual_mech_type))
611             duplicateOid(&tmpMinor, ctx->mechanismUsed, actual_mech_type);
612     }
613     if (innerOutputToken.value != NULL) {
614         tmpMajor = gssEapMakeToken(&tmpMinor, ctx, &innerOutputToken,
615                                    sm->outputTokenType, output_token);
616         if (GSS_ERROR(tmpMajor)) {
617             major = tmpMajor;
618             *minor = tmpMinor;
619             goto cleanup;
620         }
621     }
622     if (ret_flags != NULL)
623         *ret_flags = ctx->gssFlags;
624     if (time_rec != NULL)
625         gssEapContextTime(&tmpMinor, ctx, time_rec);
626
627     assert(ctx->state == EAP_STATE_ESTABLISHED || major == GSS_S_CONTINUE_NEEDED);
628
629 cleanup:
630     GSSEAP_MUTEX_UNLOCK(&ctx->mutex);
631
632     if (GSS_ERROR(major))
633         gssEapReleaseContext(&tmpMinor, context_handle);
634
635     gss_release_buffer(&tmpMinor, &innerOutputToken);
636
637     return major;
638 }