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dbcheck: cope with objects disappearing during checking
[Samba.git] / source4 / ntp_signd / ntp_signd.c
blobc6d605699f6dedaa91fa648af05e37feb17613ca
1 /*
2 Unix SMB/CIFS implementation.
3
4 NTP packet signing server
5
6 Copyright (C) Andrew Bartlett <abartlet@samba.org> 2005
7 Copyright (C) Andrew Tridgell 2005
8 Copyright (C) Stefan Metzmacher 2005
9
10 This program is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 3 of the License, or
13 (at your option) any later version.
14
15 This program is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
19
20 You should have received a copy of the GNU General Public License
21 along with this program. If not, see <http://www.gnu.org/licenses/>.
22 */
23
24 #include "includes.h"
25 #include "smbd/service_task.h"
26 #include "smbd/service.h"
27 #include "smbd/service_stream.h"
28 #include "smbd/process_model.h"
29 #include "lib/stream/packet.h"
30 #include "lib/tsocket/tsocket.h"
31 #include "libcli/util/tstream.h"
32 #include "librpc/gen_ndr/ndr_ntp_signd.h"
33 #include "param/param.h"
34 #include "dsdb/samdb/samdb.h"
35 #include "auth/auth.h"
36 #include "libcli/security/security.h"
37 #include "libcli/ldap/ldap_ndr.h"
38 #include <ldb.h>
39 #include <ldb_errors.h>
40 #include "../lib/crypto/md5.h"
41 #include "system/network.h"
42 #include "system/passwd.h"
43
44 NTSTATUS server_service_ntp_signd_init(void);
45
46 /*
47 top level context structure for the ntp_signd server
48 */
49 struct ntp_signd_server {
50 struct task_server *task;
51 struct ldb_context *samdb;
52 };
53
54 /*
55 state of an open connection
56 */
57 struct ntp_signd_connection {
58 /* stream connection we belong to */
59 struct stream_connection *conn;
60
61 /* the ntp_signd_server the connection belongs to */
62 struct ntp_signd_server *ntp_signd;
63
64 struct tstream_context *tstream;
65
66 struct tevent_queue *send_queue;
67 };
68
69 static void ntp_signd_terminate_connection(struct ntp_signd_connection *ntp_signd_conn, const char *reason)
70 {
71 stream_terminate_connection(ntp_signd_conn->conn, reason);
72 }
73
74 static NTSTATUS signing_failure(struct ntp_signd_connection *ntp_signdconn,
75 TALLOC_CTX *mem_ctx,
76 DATA_BLOB *output,
77 uint32_t packet_id)
78 {
79 struct signed_reply signed_reply;
80 enum ndr_err_code ndr_err;
81
82 signed_reply.op = SIGNING_FAILURE;
83 signed_reply.packet_id = packet_id;
84 signed_reply.signed_packet = data_blob(NULL, 0);
85
86 ndr_err = ndr_push_struct_blob(output, mem_ctx, &signed_reply,
87 (ndr_push_flags_fn_t)ndr_push_signed_reply);
88
89 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
90 DEBUG(1,("failed to push ntp error reply\n"));
91 return ndr_map_error2ntstatus(ndr_err);
92 }
93
94 return NT_STATUS_OK;
95 }
96
97 /*
98 receive a full packet on a NTP_SIGND connection
99 */
100 static NTSTATUS ntp_signd_process(struct ntp_signd_connection *ntp_signd_conn,
101 TALLOC_CTX *mem_ctx,
102 DATA_BLOB *input,
103 DATA_BLOB *output)
104 {
105 const struct dom_sid *domain_sid;
106 struct dom_sid *sid;
107 struct sign_request sign_request;
108 struct signed_reply signed_reply;
109 enum ndr_err_code ndr_err;
110 struct ldb_result *res;
111 const char *attrs[] = { "unicodePwd", "userAccountControl", "cn", NULL };
112 struct MD5Context ctx;
113 struct samr_Password *nt_hash;
114 uint32_t user_account_control;
115 int ret;
116
117 ndr_err = ndr_pull_struct_blob_all(input, mem_ctx,
118 &sign_request,
119 (ndr_pull_flags_fn_t)ndr_pull_sign_request);
120
121 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
122 DEBUG(1,("failed to parse ntp signing request\n"));
123 dump_data(1, input->data, input->length);
124 return ndr_map_error2ntstatus(ndr_err);
125 }
126
127 /* We need to implement 'check signature' and 'request server
128 * to sign' operations at some point */
129 if (sign_request.op != SIGN_TO_CLIENT) {
130 return signing_failure(ntp_signd_conn,
131 mem_ctx,
132 output,
133 sign_request.packet_id);
134 }
135
136 /* We need to implement 'check signature' and 'request server
137 * to sign' operations at some point */
138 if (sign_request.version != NTP_SIGND_PROTOCOL_VERSION_0) {
139 return signing_failure(ntp_signd_conn,
140 mem_ctx,
141 output,
142 sign_request.packet_id);
143 }
144
145 domain_sid = samdb_domain_sid(ntp_signd_conn->ntp_signd->samdb);
146 if (domain_sid == NULL) {
147 return signing_failure(ntp_signd_conn,
148 mem_ctx,
149 output,
150 sign_request.packet_id);
151 }
152
153 /* The top bit is a 'key selector' */
154 sid = dom_sid_add_rid(mem_ctx, domain_sid,
155 sign_request.key_id & 0x7FFFFFFF);
156 if (sid == NULL) {
157 talloc_free(mem_ctx);
158 return signing_failure(ntp_signd_conn,
159 mem_ctx,
160 output,
161 sign_request.packet_id);
162 }
163
164 ret = ldb_search(ntp_signd_conn->ntp_signd->samdb, mem_ctx,
165 &res,
166 ldb_get_default_basedn(ntp_signd_conn->ntp_signd->samdb),
167 LDB_SCOPE_SUBTREE,
168 attrs,
169 "(&(objectSid=%s)(objectClass=user))",
170 ldap_encode_ndr_dom_sid(mem_ctx, sid));
171 if (ret != LDB_SUCCESS) {
172 DEBUG(2, ("Failed to search for SID %s in SAM for NTP signing: "
173 "%s\n",
174 dom_sid_string(mem_ctx, sid),
175 ldb_errstring(ntp_signd_conn->ntp_signd->samdb)));
176 return signing_failure(ntp_signd_conn,
177 mem_ctx,
178 output,
179 sign_request.packet_id);
180 }
181
182 if (res->count == 0) {
183 DEBUG(5, ("Failed to find SID %s in SAM for NTP signing\n",
184 dom_sid_string(mem_ctx, sid)));
185 } else if (res->count != 1) {
186 DEBUG(1, ("Found SID %s %u times in SAM for NTP signing\n",
187 dom_sid_string(mem_ctx, sid), res->count));
188 return signing_failure(ntp_signd_conn,
189 mem_ctx,
190 output,
191 sign_request.packet_id);
192 }
193
194 user_account_control = ldb_msg_find_attr_as_uint(res->msgs[0],
195 "userAccountControl",
196 0);
197
198 if (user_account_control & UF_ACCOUNTDISABLE) {
199 DEBUG(1, ("Account %s for SID [%s] is disabled\n",
200 ldb_dn_get_linearized(res->msgs[0]->dn),
201 dom_sid_string(mem_ctx, sid)));
202 return NT_STATUS_ACCESS_DENIED;
203 }
204
205 if (!(user_account_control & (UF_INTERDOMAIN_TRUST_ACCOUNT|UF_SERVER_TRUST_ACCOUNT|UF_WORKSTATION_TRUST_ACCOUNT))) {
206 DEBUG(1, ("Account %s for SID [%s] is not a trust account\n",
207 ldb_dn_get_linearized(res->msgs[0]->dn),
208 dom_sid_string(mem_ctx, sid)));
209 return NT_STATUS_ACCESS_DENIED;
210 }
211
212 nt_hash = samdb_result_hash(mem_ctx, res->msgs[0], "unicodePwd");
213 if (!nt_hash) {
214 DEBUG(1, ("No unicodePwd found on record of SID %s "
215 "for NTP signing\n", dom_sid_string(mem_ctx, sid)));
216 return signing_failure(ntp_signd_conn,
217 mem_ctx,
218 output,
219 sign_request.packet_id);
220 }
221
222 /* Generate the reply packet */
223 signed_reply.packet_id = sign_request.packet_id;
224 signed_reply.op = SIGNING_SUCCESS;
225 signed_reply.signed_packet = data_blob_talloc(mem_ctx,
226 NULL,
227 sign_request.packet_to_sign.length + 20);
228
229 if (!signed_reply.signed_packet.data) {
230 return signing_failure(ntp_signd_conn,
231 mem_ctx,
232 output,
233 sign_request.packet_id);
234 }
235
236 memcpy(signed_reply.signed_packet.data, sign_request.packet_to_sign.data, sign_request.packet_to_sign.length);
237 SIVAL(signed_reply.signed_packet.data, sign_request.packet_to_sign.length, sign_request.key_id);
238
239 /* Sign the NTP response with the unicodePwd */
240 MD5Init(&ctx);
241 MD5Update(&ctx, nt_hash->hash, sizeof(nt_hash->hash));
242 MD5Update(&ctx, sign_request.packet_to_sign.data, sign_request.packet_to_sign.length);
243 MD5Final(signed_reply.signed_packet.data + sign_request.packet_to_sign.length + 4, &ctx);
244
245
246 /* Place it into the packet for the wire */
247 ndr_err = ndr_push_struct_blob(output, mem_ctx, &signed_reply,
248 (ndr_push_flags_fn_t)ndr_push_signed_reply);
249
250 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
251 DEBUG(1,("failed to push ntp error reply\n"));
252 return ndr_map_error2ntstatus(ndr_err);
253 }
254
255 return NT_STATUS_OK;
256 }
257
258 /*
259 called on a tcp recv
260 */
261 static void ntp_signd_recv(struct stream_connection *conn, uint16_t flags)
262 {
263 struct ntp_signd_connection *ntp_signd_conn = talloc_get_type(conn->private_data,
264 struct ntp_signd_connection);
265 ntp_signd_terminate_connection(ntp_signd_conn,
266 "ntp_signd_recv: called");
267 }
268
269 /*
270 called when we can write to a connection
271 */
272 static void ntp_signd_send(struct stream_connection *conn, uint16_t flags)
273 {
274 struct ntp_signd_connection *ntp_signd_conn = talloc_get_type(conn->private_data,
275 struct ntp_signd_connection);
276 /* this should never be triggered! */
277 ntp_signd_terminate_connection(ntp_signd_conn,
278 "ntp_signd_send: called");
279 }
280
281 struct ntp_signd_call {
282 struct ntp_signd_connection *ntp_signd_conn;
283 DATA_BLOB in;
284 DATA_BLOB out;
285 uint8_t out_hdr[4];
286 struct iovec out_iov[2];
287 };
288
289 static void ntp_signd_call_writev_done(struct tevent_req *subreq);
290
291 static void ntp_signd_call_loop(struct tevent_req *subreq)
292 {
293 struct ntp_signd_connection *ntp_signd_conn = tevent_req_callback_data(subreq,
294 struct ntp_signd_connection);
295 struct ntp_signd_call *call;
296 NTSTATUS status;
297
298 call = talloc(ntp_signd_conn, struct ntp_signd_call);
299 if (call == NULL) {
300 ntp_signd_terminate_connection(ntp_signd_conn,
301 "ntp_signd_call_loop: "
302 "no memory for ntp_signd_call");
303 return;
304 }
305 call->ntp_signd_conn = ntp_signd_conn;
306
307 status = tstream_read_pdu_blob_recv(subreq,
308 call,
309 &call->in);
310 TALLOC_FREE(subreq);
311 if (!NT_STATUS_IS_OK(status)) {
312 const char *reason;
313
314 reason = talloc_asprintf(call, "ntp_signd_call_loop: "
315 "tstream_read_pdu_blob_recv() - %s",
316 nt_errstr(status));
317 if (reason == NULL) {
318 reason = nt_errstr(status);
319 }
320
321 ntp_signd_terminate_connection(ntp_signd_conn, reason);
322 return;
323 }
324
325 DEBUG(10,("Received NTP TCP packet of length %lu from %s\n",
326 (long) call->in.length,
327 tsocket_address_string(ntp_signd_conn->conn->remote_address, call)));
328
329 /* skip length header */
330 call->in.data +=4;
331 call->in.length -= 4;
332
333 status = ntp_signd_process(ntp_signd_conn,
334 call,
335 &call->in,
336 &call->out);
337 if (! NT_STATUS_IS_OK(status)) {
338 const char *reason;
339
340 reason = talloc_asprintf(call, "ntp_signd_process failed: %s",
341 nt_errstr(status));
342 if (reason == NULL) {
343 reason = nt_errstr(status);
344 }
345
346 ntp_signd_terminate_connection(ntp_signd_conn, reason);
347 return;
348 }
349
350 /* First add the length of the out buffer */
351 RSIVAL(call->out_hdr, 0, call->out.length);
352 call->out_iov[0].iov_base = (char *) call->out_hdr;
353 call->out_iov[0].iov_len = 4;
354
355 call->out_iov[1].iov_base = (char *) call->out.data;
356 call->out_iov[1].iov_len = call->out.length;
357
358 subreq = tstream_writev_queue_send(call,
359 ntp_signd_conn->conn->event.ctx,
360 ntp_signd_conn->tstream,
361 ntp_signd_conn->send_queue,
362 call->out_iov, 2);
363 if (subreq == NULL) {
364 ntp_signd_terminate_connection(ntp_signd_conn, "ntp_signd_call_loop: "
365 "no memory for tstream_writev_queue_send");
366 return;
367 }
368
369 tevent_req_set_callback(subreq, ntp_signd_call_writev_done, call);
370
371 /*
372 * The NTP tcp pdu's has the length as 4 byte (initial_read_size),
373 * packet_full_request_u32 provides the pdu length then.
374 */
375 subreq = tstream_read_pdu_blob_send(ntp_signd_conn,
376 ntp_signd_conn->conn->event.ctx,
377 ntp_signd_conn->tstream,
378 4, /* initial_read_size */
379 packet_full_request_u32,
380 ntp_signd_conn);
381 if (subreq == NULL) {
382 ntp_signd_terminate_connection(ntp_signd_conn, "ntp_signd_call_loop: "
383 "no memory for tstream_read_pdu_blob_send");
384 return;
385 }
386 tevent_req_set_callback(subreq, ntp_signd_call_loop, ntp_signd_conn);
387 }
388
389 static void ntp_signd_call_writev_done(struct tevent_req *subreq)
390 {
391 struct ntp_signd_call *call = tevent_req_callback_data(subreq,
392 struct ntp_signd_call);
393 int sys_errno;
394 int rc;
395
396 rc = tstream_writev_queue_recv(subreq, &sys_errno);
397 TALLOC_FREE(subreq);
398 if (rc == -1) {
399 const char *reason;
400
401 reason = talloc_asprintf(call, "ntp_signd_call_writev_done: "
402 "tstream_writev_queue_recv() - %d:%s",
403 sys_errno, strerror(sys_errno));
404 if (!reason) {
405 reason = "ntp_signd_call_writev_done: "
406 "tstream_writev_queue_recv() failed";
407 }
408
409 ntp_signd_terminate_connection(call->ntp_signd_conn, reason);
410 return;
411 }
412
413 /* We don't care about errors */
414
415 talloc_free(call);
416 }
417
418 /*
419 called when we get a new connection
420 */
421 static void ntp_signd_accept(struct stream_connection *conn)
422 {
423 struct ntp_signd_server *ntp_signd = talloc_get_type(conn->private_data,
424 struct ntp_signd_server);
425 struct ntp_signd_connection *ntp_signd_conn;
426 struct tevent_req *subreq;
427 int rc;
428
429 ntp_signd_conn = talloc_zero(conn, struct ntp_signd_connection);
430 if (ntp_signd_conn == NULL) {
431 stream_terminate_connection(conn,
432 "ntp_signd_accept: out of memory");
433 return;
434 }
435
436 ntp_signd_conn->send_queue = tevent_queue_create(conn,
437 "ntp_signd_accept");
438 if (ntp_signd_conn->send_queue == NULL) {
439 stream_terminate_connection(conn,
440 "ntp_signd_accept: out of memory");
441 return;
442 }
443
444 TALLOC_FREE(conn->event.fde);
445
446 rc = tstream_bsd_existing_socket(ntp_signd_conn,
447 socket_get_fd(conn->socket),
448 &ntp_signd_conn->tstream);
449 if (rc < 0) {
450 stream_terminate_connection(conn,
451 "ntp_signd_accept: out of memory");
452 return;
453 }
454
455 ntp_signd_conn->conn = conn;
456 ntp_signd_conn->ntp_signd = ntp_signd;
457 conn->private_data = ntp_signd_conn;
458
459 /*
460 * The NTP tcp pdu's has the length as 4 byte (initial_read_size),
461 * packet_full_request_u32 provides the pdu length then.
462 */
463 subreq = tstream_read_pdu_blob_send(ntp_signd_conn,
464 ntp_signd_conn->conn->event.ctx,
465 ntp_signd_conn->tstream,
466 4, /* initial_read_size */
467 packet_full_request_u32,
468 ntp_signd_conn);
469 if (subreq == NULL) {
470 ntp_signd_terminate_connection(ntp_signd_conn,
471 "ntp_signd_accept: "
472 "no memory for tstream_read_pdu_blob_send");
473 return;
474 }
475 tevent_req_set_callback(subreq, ntp_signd_call_loop, ntp_signd_conn);
476 }
477
478 static const struct stream_server_ops ntp_signd_stream_ops = {
479 .name = "ntp_signd",
480 .accept_connection = ntp_signd_accept,
481 .recv_handler = ntp_signd_recv,
482 .send_handler = ntp_signd_send
483 };
484
485 /*
486 startup the ntp_signd task
487 */
488 static void ntp_signd_task_init(struct task_server *task)
489 {
490 struct ntp_signd_server *ntp_signd;
491 NTSTATUS status;
492
493 const struct model_ops *model_ops;
494
495 const char *address;
496
497 if (!directory_create_or_exist(lpcfg_ntp_signd_socket_directory(task->lp_ctx), geteuid(), 0755)) {
498 char *error = talloc_asprintf(task, "Cannot create NTP signd pipe directory: %s",
499 lpcfg_ntp_signd_socket_directory(task->lp_ctx));
500 task_server_terminate(task,
501 error, true);
502 return;
503 }
504
505 /* within the ntp_signd task we want to be a single process, so
506 ask for the single process model ops and pass these to the
507 stream_setup_socket() call. */
508 model_ops = process_model_startup("single");
509 if (!model_ops) {
510 DEBUG(0,("Can't find 'single' process model_ops\n"));
511 return;
512 }
513
514 task_server_set_title(task, "task[ntp_signd]");
515
516 ntp_signd = talloc(task, struct ntp_signd_server);
517 if (ntp_signd == NULL) {
518 task_server_terminate(task, "ntp_signd: out of memory", true);
519 return;
520 }
521
522 ntp_signd->task = task;
523
524 /* Must be system to get at the password hashes */
525 ntp_signd->samdb = samdb_connect(ntp_signd, task->event_ctx, task->lp_ctx, system_session(task->lp_ctx), 0);
526 if (ntp_signd->samdb == NULL) {
527 task_server_terminate(task, "ntp_signd failed to open samdb", true);
528 return;
529 }
530
531 address = talloc_asprintf(ntp_signd, "%s/socket", lpcfg_ntp_signd_socket_directory(task->lp_ctx));
532
533 status = stream_setup_socket(ntp_signd->task,
534 ntp_signd->task->event_ctx,
535 ntp_signd->task->lp_ctx,
536 model_ops,
537 &ntp_signd_stream_ops,
538 "unix", address, NULL,
539 lpcfg_socket_options(ntp_signd->task->lp_ctx),
540 ntp_signd);
541 if (!NT_STATUS_IS_OK(status)) {
542 DEBUG(0,("Failed to bind to %s - %s\n",
543 address, nt_errstr(status)));
544 return;
545 }
546
547 }
548
549
550 /* called at smbd startup - register ourselves as a server service */
551 NTSTATUS server_service_ntp_signd_init(void)
552 {
553 return register_server_service("ntp_signd", ntp_signd_task_init);
554 }
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