rpc_server: correct the chunk_size depending on the signature size
[tprouty/samba.git] / source4 / rpc_server / dcesrv_auth.c
1 /* 
2    Unix SMB/CIFS implementation.
3
4    server side dcerpc authentication code
5
6    Copyright (C) Andrew Tridgell 2003
7    Copyright (C) Stefan (metze) Metzmacher 2004
8
9    This program is free software; you can redistribute it and/or modify
10    it under the terms of the GNU General Public License as published by
11    the Free Software Foundation; either version 3 of the License, or
12    (at your option) any later version.
13    
14    This program is distributed in the hope that it will be useful,
15    but WITHOUT ANY WARRANTY; without even the implied warranty of
16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17    GNU General Public License for more details.
18    
19    You should have received a copy of the GNU General Public License
20    along with this program.  If not, see <http://www.gnu.org/licenses/>.
21 */
22
23 #include "includes.h"
24 #include "rpc_server/dcerpc_server.h"
25 #include "rpc_server/dcerpc_server_proto.h"
26 #include "librpc/rpc/dcerpc_proto.h"
27 #include "librpc/gen_ndr/ndr_dcerpc.h"
28 #include "auth/credentials/credentials.h"
29 #include "auth/gensec/gensec.h"
30 #include "param/param.h"
31
32 /*
33   parse any auth information from a dcerpc bind request
34   return false if we can't handle the auth request for some 
35   reason (in which case we send a bind_nak)
36 */
37 bool dcesrv_auth_bind(struct dcesrv_call_state *call)
38 {
39         struct cli_credentials *server_credentials;
40         struct ncacn_packet *pkt = &call->pkt;
41         struct dcesrv_connection *dce_conn = call->conn;
42         struct dcesrv_auth *auth = &dce_conn->auth_state;
43         NTSTATUS status;
44         enum ndr_err_code ndr_err;
45
46         if (pkt->u.bind.auth_info.length == 0) {
47                 dce_conn->auth_state.auth_info = NULL;
48                 return true;
49         }
50
51         dce_conn->auth_state.auth_info = talloc(dce_conn, struct dcerpc_auth);
52         if (!dce_conn->auth_state.auth_info) {
53                 return false;
54         }
55
56         ndr_err = ndr_pull_struct_blob(&pkt->u.bind.auth_info,
57                                        call, NULL,
58                                        dce_conn->auth_state.auth_info,
59                                        (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
60         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
61                 return false;
62         }
63
64         status = gensec_server_start(dce_conn, call->event_ctx, call->conn->dce_ctx->lp_ctx, call->msg_ctx, &auth->gensec_security);
65         if (!NT_STATUS_IS_OK(status)) {
66                 DEBUG(1, ("Failed to start GENSEC for DCERPC server: %s\n", nt_errstr(status)));
67                 return false;
68         }
69
70         server_credentials 
71                 = cli_credentials_init(call);
72         if (!server_credentials) {
73                 DEBUG(1, ("Failed to init server credentials\n"));
74                 return false;
75         }
76         
77         cli_credentials_set_conf(server_credentials, call->conn->dce_ctx->lp_ctx);
78         status = cli_credentials_set_machine_account(server_credentials, call->conn->dce_ctx->lp_ctx);
79         if (!NT_STATUS_IS_OK(status)) {
80                 DEBUG(10, ("Failed to obtain server credentials, perhaps a standalone server?: %s\n", nt_errstr(status)));
81                 talloc_free(server_credentials);
82                 server_credentials = NULL;
83         }
84
85         gensec_set_credentials(auth->gensec_security, server_credentials);
86
87         status = gensec_start_mech_by_authtype(auth->gensec_security, auth->auth_info->auth_type, 
88                                                auth->auth_info->auth_level);
89
90         if (!NT_STATUS_IS_OK(status)) {
91                 DEBUG(1, ("Failed to start GENSEC mechanism for DCERPC server: auth_type=%d, auth_level=%d: %s\n", 
92                           (int)auth->auth_info->auth_type,
93                           (int)auth->auth_info->auth_level,
94                           nt_errstr(status)));
95                 return false;
96         }
97
98         return true;
99 }
100
101 /*
102   add any auth information needed in a bind ack, and process the authentication
103   information found in the bind.
104 */
105 NTSTATUS dcesrv_auth_bind_ack(struct dcesrv_call_state *call, struct ncacn_packet *pkt)
106 {
107         struct dcesrv_connection *dce_conn = call->conn;
108         NTSTATUS status;
109
110         if (!call->conn->auth_state.gensec_security) {
111                 return NT_STATUS_OK;
112         }
113
114         status = gensec_update(dce_conn->auth_state.gensec_security,
115                                call,
116                                dce_conn->auth_state.auth_info->credentials, 
117                                &dce_conn->auth_state.auth_info->credentials);
118         
119         if (NT_STATUS_IS_OK(status)) {
120                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
121                                              &dce_conn->auth_state.session_info);
122                 if (!NT_STATUS_IS_OK(status)) {
123                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
124                         return status;
125                 }
126
127                 if (dce_conn->state_flags & DCESRV_CALL_STATE_FLAG_HEADER_SIGNING) {
128                         gensec_want_feature(dce_conn->auth_state.gensec_security,
129                                             GENSEC_FEATURE_SIGN_PKT_HEADER);
130                 }
131
132                 /* Now that we are authenticated, go back to the generic session key... */
133                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
134                 return NT_STATUS_OK;
135         } else if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
136                 dce_conn->auth_state.auth_info->auth_pad_length = 0;
137                 dce_conn->auth_state.auth_info->auth_reserved = 0;
138                 return NT_STATUS_OK;
139         } else {
140                 DEBUG(2, ("Failed to start dcesrv auth negotiate: %s\n", nt_errstr(status)));
141                 return status;
142         }
143 }
144
145
146 /*
147   process the final stage of a auth request
148 */
149 bool dcesrv_auth_auth3(struct dcesrv_call_state *call)
150 {
151         struct ncacn_packet *pkt = &call->pkt;
152         struct dcesrv_connection *dce_conn = call->conn;
153         NTSTATUS status;
154         enum ndr_err_code ndr_err;
155
156         /* We can't work without an existing gensec state, and an new blob to feed it */
157         if (!dce_conn->auth_state.auth_info ||
158             !dce_conn->auth_state.gensec_security ||
159             pkt->u.auth3.auth_info.length == 0) {
160                 return false;
161         }
162
163         ndr_err = ndr_pull_struct_blob(&pkt->u.auth3.auth_info,
164                                        call, NULL,
165                                        dce_conn->auth_state.auth_info,
166                                        (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
167         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
168                 return false;
169         }
170
171         /* Pass the extra data we got from the client down to gensec for processing */
172         status = gensec_update(dce_conn->auth_state.gensec_security,
173                                call,
174                                dce_conn->auth_state.auth_info->credentials, 
175                                &dce_conn->auth_state.auth_info->credentials);
176         if (NT_STATUS_IS_OK(status)) {
177                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
178                                              &dce_conn->auth_state.session_info);
179                 if (!NT_STATUS_IS_OK(status)) {
180                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
181                         return false;
182                 }
183                 /* Now that we are authenticated, go back to the generic session key... */
184                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
185                 return true;
186         } else {
187                 DEBUG(4, ("dcesrv_auth_auth3: failed to authenticate: %s\n", 
188                           nt_errstr(status)));
189                 return false;
190         }
191
192         return true;
193 }
194
195 /*
196   parse any auth information from a dcerpc alter request
197   return false if we can't handle the auth request for some 
198   reason (in which case we send a bind_nak (is this true for here?))
199 */
200 bool dcesrv_auth_alter(struct dcesrv_call_state *call)
201 {
202         struct ncacn_packet *pkt = &call->pkt;
203         struct dcesrv_connection *dce_conn = call->conn;
204         enum ndr_err_code ndr_err;
205
206         /* on a pure interface change there is no auth blob */
207         if (pkt->u.alter.auth_info.length == 0) {
208                 return true;
209         }
210
211         /* We can't work without an existing gensec state */
212         if (!dce_conn->auth_state.gensec_security) {
213                 return false;
214         }
215
216         dce_conn->auth_state.auth_info = talloc(dce_conn, struct dcerpc_auth);
217         if (!dce_conn->auth_state.auth_info) {
218                 return false;
219         }
220
221         ndr_err = ndr_pull_struct_blob(&pkt->u.alter.auth_info,
222                                        call, NULL,
223                                        dce_conn->auth_state.auth_info,
224                                        (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
225         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
226                 return false;
227         }
228
229         return true;
230 }
231
232 /*
233   add any auth information needed in a alter ack, and process the authentication
234   information found in the alter.
235 */
236 NTSTATUS dcesrv_auth_alter_ack(struct dcesrv_call_state *call, struct ncacn_packet *pkt)
237 {
238         struct dcesrv_connection *dce_conn = call->conn;
239         NTSTATUS status;
240
241         /* on a pure interface change there is no auth_info structure
242            setup */
243         if (!call->conn->auth_state.auth_info ||
244             dce_conn->auth_state.auth_info->credentials.length == 0) {
245                 return NT_STATUS_OK;
246         }
247
248         if (!call->conn->auth_state.gensec_security) {
249                 return NT_STATUS_INVALID_PARAMETER;
250         }
251
252         status = gensec_update(dce_conn->auth_state.gensec_security,
253                                call,
254                                dce_conn->auth_state.auth_info->credentials, 
255                                &dce_conn->auth_state.auth_info->credentials);
256
257         if (NT_STATUS_IS_OK(status)) {
258                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
259                                              &dce_conn->auth_state.session_info);
260                 if (!NT_STATUS_IS_OK(status)) {
261                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
262                         return status;
263                 }
264
265                 /* Now that we are authenticated, got back to the generic session key... */
266                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
267                 return NT_STATUS_OK;
268         } else if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
269                 dce_conn->auth_state.auth_info->auth_pad_length = 0;
270                 dce_conn->auth_state.auth_info->auth_reserved = 0;
271                 return NT_STATUS_OK;
272         }
273
274         DEBUG(2, ("Failed to finish dcesrv auth alter_ack: %s\n", nt_errstr(status)));
275         return status;
276 }
277
278 /*
279   generate a CONNECT level verifier
280 */
281 static NTSTATUS dcesrv_connect_verifier(TALLOC_CTX *mem_ctx, DATA_BLOB *blob)
282 {
283         *blob = data_blob_talloc(mem_ctx, NULL, 16);
284         if (blob->data == NULL) {
285                 return NT_STATUS_NO_MEMORY;
286         }
287         SIVAL(blob->data, 0, 1);
288         memset(blob->data+4, 0, 12);
289         return NT_STATUS_OK;
290 }
291
292 /*
293   generate a CONNECT level verifier
294 */
295 static NTSTATUS dcesrv_check_connect_verifier(DATA_BLOB *blob)
296 {
297         if (blob->length != 16 ||
298             IVAL(blob->data, 0) != 1) {
299                 return NT_STATUS_ACCESS_DENIED;
300         }
301         return NT_STATUS_OK;
302 }
303
304
305 /*
306   check credentials on a request
307 */
308 bool dcesrv_auth_request(struct dcesrv_call_state *call, DATA_BLOB *full_packet)
309 {
310         struct ncacn_packet *pkt = &call->pkt;
311         struct dcesrv_connection *dce_conn = call->conn;
312         DATA_BLOB auth_blob;
313         struct dcerpc_auth auth;
314         struct ndr_pull *ndr;
315         NTSTATUS status;
316         enum ndr_err_code ndr_err;
317
318         if (!dce_conn->auth_state.auth_info ||
319             !dce_conn->auth_state.gensec_security) {
320                 return true;
321         }
322
323         auth_blob.length = 8 + pkt->auth_length;
324
325         /* check for a valid length */
326         if (pkt->u.request.stub_and_verifier.length < auth_blob.length) {
327                 return false;
328         }
329
330         auth_blob.data = 
331                 pkt->u.request.stub_and_verifier.data + 
332                 pkt->u.request.stub_and_verifier.length - auth_blob.length;
333         pkt->u.request.stub_and_verifier.length -= auth_blob.length;
334
335         /* pull the auth structure */
336         ndr = ndr_pull_init_blob(&auth_blob, call, lp_iconv_convenience(call->conn->dce_ctx->lp_ctx));
337         if (!ndr) {
338                 return false;
339         }
340
341         if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
342                 ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
343         }
344
345         ndr_err = ndr_pull_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS, &auth);
346         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
347                 talloc_free(ndr);
348                 return false;
349         }
350
351         /* check signature or unseal the packet */
352         switch (dce_conn->auth_state.auth_info->auth_level) {
353         case DCERPC_AUTH_LEVEL_PRIVACY:
354                 status = gensec_unseal_packet(dce_conn->auth_state.gensec_security,
355                                               call,
356                                               full_packet->data + DCERPC_REQUEST_LENGTH,
357                                               pkt->u.request.stub_and_verifier.length, 
358                                               full_packet->data,
359                                               full_packet->length-auth.credentials.length,
360                                               &auth.credentials);
361                 memcpy(pkt->u.request.stub_and_verifier.data, 
362                        full_packet->data + DCERPC_REQUEST_LENGTH,
363                        pkt->u.request.stub_and_verifier.length);
364                 break;
365
366         case DCERPC_AUTH_LEVEL_INTEGRITY:
367                 status = gensec_check_packet(dce_conn->auth_state.gensec_security,
368                                              call,
369                                              pkt->u.request.stub_and_verifier.data, 
370                                              pkt->u.request.stub_and_verifier.length,
371                                              full_packet->data,
372                                              full_packet->length-auth.credentials.length,
373                                              &auth.credentials);
374                 break;
375
376         case DCERPC_AUTH_LEVEL_CONNECT:
377                 status = dcesrv_check_connect_verifier(&auth.credentials);
378                 break;
379
380         default:
381                 status = NT_STATUS_INVALID_LEVEL;
382                 break;
383         }
384
385         /* remove the indicated amount of padding */
386         if (pkt->u.request.stub_and_verifier.length < auth.auth_pad_length) {
387                 talloc_free(ndr);
388                 return false;
389         }
390         pkt->u.request.stub_and_verifier.length -= auth.auth_pad_length;
391         talloc_free(ndr);
392
393         return NT_STATUS_IS_OK(status);
394 }
395
396
397 /* 
398    push a signed or sealed dcerpc request packet into a blob
399 */
400 bool dcesrv_auth_response(struct dcesrv_call_state *call,
401                           DATA_BLOB *blob, size_t sig_size,
402                           struct ncacn_packet *pkt)
403 {
404         struct dcesrv_connection *dce_conn = call->conn;
405         NTSTATUS status;
406         enum ndr_err_code ndr_err;
407         struct ndr_push *ndr;
408         uint32_t payload_length;
409         DATA_BLOB creds2;
410
411         /* non-signed packets are simple */
412         if (!dce_conn->auth_state.auth_info || !dce_conn->auth_state.gensec_security) {
413                 status = ncacn_push_auth(blob, call, lp_iconv_convenience(dce_conn->dce_ctx->lp_ctx), pkt, NULL);
414                 return NT_STATUS_IS_OK(status);
415         }
416
417         ndr = ndr_push_init_ctx(call, lp_iconv_convenience(dce_conn->dce_ctx->lp_ctx));
418         if (!ndr) {
419                 return false;
420         }
421
422         if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
423                 ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
424         }
425
426         ndr_err = ndr_push_ncacn_packet(ndr, NDR_SCALARS|NDR_BUFFERS, pkt);
427         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
428                 return false;
429         }
430
431         /* pad to 16 byte multiple, match win2k3 */
432         dce_conn->auth_state.auth_info->auth_pad_length = NDR_ALIGN(ndr, 16);
433         ndr_push_zero(ndr, dce_conn->auth_state.auth_info->auth_pad_length);
434
435         payload_length = ndr->offset - DCERPC_REQUEST_LENGTH;
436
437         if (dce_conn->auth_state.auth_info->auth_level == DCERPC_AUTH_LEVEL_CONNECT) {
438                 status = dcesrv_connect_verifier(call,
439                                                  &dce_conn->auth_state.auth_info->credentials);
440                 if (!NT_STATUS_IS_OK(status)) {
441                         return false;
442                 }
443         } else {
444
445                 /* We hope this length is accruate.  If must be if the
446                  * GENSEC mech does AEAD signing of the packet
447                  * headers */
448                 dce_conn->auth_state.auth_info->credentials
449                         = data_blob_talloc(call, NULL, sig_size);
450                 data_blob_clear(&dce_conn->auth_state.auth_info->credentials);
451         }
452
453         /* add the auth verifier */
454         ndr_err = ndr_push_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS,
455                                       dce_conn->auth_state.auth_info);
456         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
457                 return false;
458         }
459
460         /* extract the whole packet as a blob */
461         *blob = ndr_push_blob(ndr);
462
463         /* fill in the fragment length and auth_length, we can't fill
464            in these earlier as we don't know the signature length (it
465            could be variable length) */
466         dcerpc_set_frag_length(blob, blob->length);
467
468         /* We hope this value is accruate.  If must be if the GENSEC
469          * mech does AEAD signing of the packet headers */
470         dcerpc_set_auth_length(blob, dce_conn->auth_state.auth_info->credentials.length);
471
472         /* sign or seal the packet */
473         switch (dce_conn->auth_state.auth_info->auth_level) {
474         case DCERPC_AUTH_LEVEL_PRIVACY:
475                 status = gensec_seal_packet(dce_conn->auth_state.gensec_security, 
476                                             call,
477                                             ndr->data + DCERPC_REQUEST_LENGTH, 
478                                             payload_length,
479                                             blob->data,
480                                             blob->length - dce_conn->auth_state.auth_info->credentials.length,
481                                             &creds2);
482
483                 if (NT_STATUS_IS_OK(status)) {
484                         blob->length -= dce_conn->auth_state.auth_info->credentials.length;
485                         if (!data_blob_append(call, blob, creds2.data, creds2.length))
486                                 status = NT_STATUS_NO_MEMORY;
487                         else
488                                 status = NT_STATUS_OK;
489                 }
490
491                 /* If we did AEAD signing of the packet headers, then we hope
492                  * this value didn't change... */
493                 dcerpc_set_auth_length(blob, creds2.length);
494                 dcerpc_set_frag_length(blob, dcerpc_get_frag_length(blob)+creds2.length);
495                 data_blob_free(&creds2);
496                 break;
497
498         case DCERPC_AUTH_LEVEL_INTEGRITY:
499                 status = gensec_sign_packet(dce_conn->auth_state.gensec_security, 
500                                             call,
501                                             ndr->data + DCERPC_REQUEST_LENGTH, 
502                                             payload_length,
503                                             blob->data,
504                                             blob->length - dce_conn->auth_state.auth_info->credentials.length,
505                                             &creds2);
506                 if (NT_STATUS_IS_OK(status)) {
507                         blob->length -= dce_conn->auth_state.auth_info->credentials.length;
508                         if (!data_blob_append(call, blob, creds2.data, creds2.length))
509                                 status = NT_STATUS_NO_MEMORY;
510                         else
511                                 status = NT_STATUS_OK;
512                 }
513
514                 /* If we did AEAD signing of the packet headers, then we hope
515                  * this value didn't change... */
516                 dcerpc_set_auth_length(blob, creds2.length);
517                 dcerpc_set_frag_length(blob, dcerpc_get_frag_length(blob)+creds2.length);
518                 data_blob_free(&creds2);
519                 break;
520
521         case DCERPC_AUTH_LEVEL_CONNECT:
522                 break;
523
524         default:
525                 status = NT_STATUS_INVALID_LEVEL;
526                 break;
527         }
528
529         data_blob_free(&dce_conn->auth_state.auth_info->credentials);
530
531         if (!NT_STATUS_IS_OK(status)) {
532                 return false;
533         }       
534
535         return true;
536 }