source: vendor/3.5.0/source3/auth/auth_server.c

Last change on this file was 414, checked in by Herwig Bauernfeind, 16 years ago

Samba 3.5.0: Initial import
File size: 13.0 KB
Line 
1/*
2 Unix SMB/CIFS implementation.
3 Authenticate to a remote server
4 Copyright (C) Andrew Tridgell 1992-1998
5 Copyright (C) Andrew Bartlett 2001
6
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
11
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>.
19*/
20
21#include "includes.h"
22
23#undef DBGC_CLASS
24#define DBGC_CLASS DBGC_AUTH
25
26extern userdom_struct current_user_info;
27
28/****************************************************************************
29 Support for server level security.
30****************************************************************************/
31
32static struct cli_state *server_cryptkey(TALLOC_CTX *mem_ctx)
33{
34 struct cli_state *cli = NULL;
35 char *desthost = NULL;
36 struct sockaddr_storage dest_ss;
37 const char *p;
38 char *pserver = NULL;
39 bool connected_ok = False;
40 struct named_mutex *mutex = NULL;
41 NTSTATUS status;
42
43 if (!(cli = cli_initialise()))
44 return NULL;
45
46 /* security = server just can't function with spnego */
47 cli->use_spnego = False;
48
49 pserver = talloc_strdup(mem_ctx, lp_passwordserver());
50 p = pserver;
51
52 while(next_token_talloc(mem_ctx, &p, &desthost, LIST_SEP)) {
53
54 desthost = talloc_sub_basic(mem_ctx,
55 current_user_info.smb_name,
56 current_user_info.domain,
57 desthost);
58 if (!desthost) {
59 return NULL;
60 }
61 strupper_m(desthost);
62
63 if(!resolve_name( desthost, &dest_ss, 0x20, false)) {
64 DEBUG(1,("server_cryptkey: Can't resolve address for %s\n",desthost));
65 continue;
66 }
67
68 if (ismyaddr((struct sockaddr *)&dest_ss)) {
69 DEBUG(1,("Password server loop - disabling password server %s\n",desthost));
70 continue;
71 }
72
73 /* we use a mutex to prevent two connections at once - when a
74 Win2k PDC get two connections where one hasn't completed a
75 session setup yet it will send a TCP reset to the first
76 connection (tridge) */
77
78 mutex = grab_named_mutex(talloc_tos(), desthost, 10);
79 if (mutex == NULL) {
80 cli_shutdown(cli);
81 return NULL;
82 }
83
84 status = cli_connect(cli, desthost, &dest_ss);
85 if (NT_STATUS_IS_OK(status)) {
86 DEBUG(3,("connected to password server %s\n",desthost));
87 connected_ok = True;
88 break;
89 }
90 DEBUG(10,("server_cryptkey: failed to connect to server %s. Error %s\n",
91 desthost, nt_errstr(status) ));
92 TALLOC_FREE(mutex);
93 }
94
95 if (!connected_ok) {
96 DEBUG(0,("password server not available\n"));
97 cli_shutdown(cli);
98 return NULL;
99 }
100
101 if (!attempt_netbios_session_request(&cli, global_myname(),
102 desthost, &dest_ss)) {
103 TALLOC_FREE(mutex);
104 DEBUG(1,("password server fails session request\n"));
105 cli_shutdown(cli);
106 return NULL;
107 }
108
109 if (strequal(desthost,myhostname())) {
110 exit_server_cleanly("Password server loop!");
111 }
112
113 DEBUG(3,("got session\n"));
114
115 status = cli_negprot(cli);
116
117 if (!NT_STATUS_IS_OK(status)) {
118 TALLOC_FREE(mutex);
119 DEBUG(1, ("%s rejected the negprot: %s\n",
120 desthost, nt_errstr(status)));
121 cli_shutdown(cli);
122 return NULL;
123 }
124
125 if (cli->protocol < PROTOCOL_LANMAN2 ||
126 !(cli->sec_mode & NEGOTIATE_SECURITY_USER_LEVEL)) {
127 TALLOC_FREE(mutex);
128 DEBUG(1,("%s isn't in user level security mode\n",desthost));
129 cli_shutdown(cli);
130 return NULL;
131 }
132
133 /* Get the first session setup done quickly, to avoid silly
134 Win2k bugs. (The next connection to the server will kill
135 this one...
136 */
137
138 if (!NT_STATUS_IS_OK(cli_session_setup(cli, "", "", 0, "", 0,
139 ""))) {
140 TALLOC_FREE(mutex);
141 DEBUG(0,("%s rejected the initial session setup (%s)\n",
142 desthost, cli_errstr(cli)));
143 cli_shutdown(cli);
144 return NULL;
145 }
146
147 TALLOC_FREE(mutex);
148
149 DEBUG(3,("password server OK\n"));
150
151 return cli;
152}
153
154struct server_security_state {
155 struct cli_state *cli;
156};
157
158/****************************************************************************
159 Send a 'keepalive' packet down the cli pipe.
160****************************************************************************/
161
162static bool send_server_keepalive(const struct timeval *now,
163 void *private_data)
164{
165 struct server_security_state *state = talloc_get_type_abort(
166 private_data, struct server_security_state);
167
168 if (!state->cli || !state->cli->initialised) {
169 return False;
170 }
171
172 if (send_keepalive(state->cli->fd)) {
173 return True;
174 }
175
176 DEBUG( 2, ( "send_server_keepalive: password server keepalive "
177 "failed.\n"));
178 cli_shutdown(state->cli);
179 state->cli = NULL;
180 return False;
181}
182
183static int destroy_server_security(struct server_security_state *state)
184{
185 if (state->cli) {
186 cli_shutdown(state->cli);
187 }
188 return 0;
189}
190
191static struct server_security_state *make_server_security_state(struct cli_state *cli)
192{
193 struct server_security_state *result;
194
195 if (!(result = talloc(NULL, struct server_security_state))) {
196 DEBUG(0, ("talloc failed\n"));
197 cli_shutdown(cli);
198 return NULL;
199 }
200
201 result->cli = cli;
202 talloc_set_destructor(result, destroy_server_security);
203
204 if (lp_keepalive() != 0) {
205 struct timeval interval;
206 interval.tv_sec = lp_keepalive();
207 interval.tv_usec = 0;
208
209 if (event_add_idle(smbd_event_context(), result, interval,
210 "server_security_keepalive",
211 send_server_keepalive,
212 result) == NULL) {
213 DEBUG(0, ("event_add_idle failed\n"));
214 TALLOC_FREE(result);
215 return NULL;
216 }
217 }
218
219 return result;
220}
221
222/****************************************************************************
223 Get the challenge out of a password server.
224****************************************************************************/
225
226static DATA_BLOB auth_get_challenge_server(const struct auth_context *auth_context,
227 void **my_private_data,
228 TALLOC_CTX *mem_ctx)
229{
230 struct cli_state *cli = server_cryptkey(mem_ctx);
231
232 if (cli) {
233 DEBUG(3,("using password server validation\n"));
234
235 if ((cli->sec_mode & NEGOTIATE_SECURITY_CHALLENGE_RESPONSE) == 0) {
236 /* We can't work with unencrypted password servers
237 unless 'encrypt passwords = no' */
238 DEBUG(5,("make_auth_info_server: Server is unencrypted, no challenge available..\n"));
239
240 /* However, it is still a perfectly fine connection
241 to pass that unencrypted password over */
242 *my_private_data =
243 (void *)make_server_security_state(cli);
244 return data_blob_null;
245 } else if (cli->secblob.length < 8) {
246 /* We can't do much if we don't get a full challenge */
247 DEBUG(2,("make_auth_info_server: Didn't receive a full challenge from server\n"));
248 cli_shutdown(cli);
249 return data_blob_null;
250 }
251
252 if (!(*my_private_data = (void *)make_server_security_state(cli))) {
253 return data_blob(NULL,0);
254 }
255
256 /* The return must be allocated on the caller's mem_ctx, as our own will be
257 destoyed just after the call. */
258 return data_blob_talloc(auth_context->mem_ctx, cli->secblob.data,8);
259 } else {
260 return data_blob_null;
261 }
262}
263
264
265/****************************************************************************
266 Check for a valid username and password in security=server mode.
267 - Validate a password with the password server.
268****************************************************************************/
269
270static NTSTATUS check_smbserver_security(const struct auth_context *auth_context,
271 void *my_private_data,
272 TALLOC_CTX *mem_ctx,
273 const auth_usersupplied_info *user_info,
274 auth_serversupplied_info **server_info)
275{
276 struct server_security_state *state = talloc_get_type_abort(
277 my_private_data, struct server_security_state);
278 struct cli_state *cli;
279 static bool tested_password_server = False;
280 static bool bad_password_server = False;
281 NTSTATUS nt_status = NT_STATUS_NOT_IMPLEMENTED;
282 bool locally_made_cli = False;
283
284 cli = state->cli;
285
286 if (cli) {
287 } else {
288 cli = server_cryptkey(mem_ctx);
289 locally_made_cli = True;
290 }
291
292 if (!cli || !cli->initialised) {
293 DEBUG(1,("password server is not connected (cli not initialised)\n"));
294 return NT_STATUS_LOGON_FAILURE;
295 }
296
297 if ((cli->sec_mode & NEGOTIATE_SECURITY_CHALLENGE_RESPONSE) == 0) {
298 if (user_info->encrypted) {
299 DEBUG(1,("password server %s is plaintext, but we are encrypted. This just can't work :-(\n", cli->desthost));
300 return NT_STATUS_LOGON_FAILURE;
301 }
302 } else {
303 if (memcmp(cli->secblob.data, auth_context->challenge.data, 8) != 0) {
304 DEBUG(1,("the challenge that the password server (%s) supplied us is not the one we gave our client. This just can't work :-(\n", cli->desthost));
305 return NT_STATUS_LOGON_FAILURE;
306 }
307 }
308
309 /*
310 * Attempt a session setup with a totally incorrect password.
311 * If this succeeds with the guest bit *NOT* set then the password
312 * server is broken and is not correctly setting the guest bit. We
313 * need to detect this as some versions of NT4.x are broken. JRA.
314 */
315
316 /* I sure as hell hope that there aren't servers out there that take
317 * NTLMv2 and have this bug, as we don't test for that...
318 * - abartlet@samba.org
319 */
320
321 if ((!tested_password_server) && (lp_paranoid_server_security())) {
322 unsigned char badpass[24];
323 char *baduser = NULL;
324
325 memset(badpass, 0x1f, sizeof(badpass));
326
327 if((user_info->nt_resp.length == sizeof(badpass)) &&
328 !memcmp(badpass, user_info->nt_resp.data, sizeof(badpass))) {
329 /*
330 * Very unlikely, our random bad password is the same as the users
331 * password.
332 */
333 memset(badpass, badpass[0]+1, sizeof(badpass));
334 }
335
336 baduser = talloc_asprintf(mem_ctx,
337 "%s%s",
338 INVALID_USER_PREFIX,
339 global_myname());
340 if (!baduser) {
341 return NT_STATUS_NO_MEMORY;
342 }
343
344 if (NT_STATUS_IS_OK(cli_session_setup(cli, baduser,
345 (char *)badpass,
346 sizeof(badpass),
347 (char *)badpass,
348 sizeof(badpass),
349 user_info->domain))) {
350
351 /*
352 * We connected to the password server so we
353 * can say we've tested it.
354 */
355 tested_password_server = True;
356
357 if ((SVAL(cli->inbuf,smb_vwv2) & 1) == 0) {
358 DEBUG(0,("server_validate: password server %s allows users as non-guest \
359with a bad password.\n", cli->desthost));
360 DEBUG(0,("server_validate: This is broken (and insecure) behaviour. Please do not \
361use this machine as the password server.\n"));
362 cli_ulogoff(cli);
363
364 /*
365 * Password server has the bug.
366 */
367 bad_password_server = True;
368 return NT_STATUS_LOGON_FAILURE;
369 }
370 cli_ulogoff(cli);
371 }
372 } else {
373
374 /*
375 * We have already tested the password server.
376 * Fail immediately if it has the bug.
377 */
378
379 if(bad_password_server) {
380 DEBUG(0,("server_validate: [1] password server %s allows users as non-guest \
381with a bad password.\n", cli->desthost));
382 DEBUG(0,("server_validate: [1] This is broken (and insecure) behaviour. Please do not \
383use this machine as the password server.\n"));
384 return NT_STATUS_LOGON_FAILURE;
385 }
386 }
387
388 /*
389 * Now we know the password server will correctly set the guest bit, or is
390 * not guest enabled, we can try with the real password.
391 */
392
393 if (!user_info->encrypted) {
394 /* Plaintext available */
395 nt_status = cli_session_setup(
396 cli, user_info->smb_name,
397 (char *)user_info->plaintext_password.data,
398 user_info->plaintext_password.length,
399 NULL, 0, user_info->domain);
400
401 } else {
402 nt_status = cli_session_setup(
403 cli, user_info->smb_name,
404 (char *)user_info->lm_resp.data,
405 user_info->lm_resp.length,
406 (char *)user_info->nt_resp.data,
407 user_info->nt_resp.length,
408 user_info->domain);
409 }
410
411 if (!NT_STATUS_IS_OK(nt_status)) {
412 DEBUG(1,("password server %s rejected the password: %s\n",
413 cli->desthost, nt_errstr(nt_status)));
414 }
415
416 /* if logged in as guest then reject */
417 if ((SVAL(cli->inbuf,smb_vwv2) & 1) != 0) {
418 DEBUG(1,("password server %s gave us guest only\n", cli->desthost));
419 nt_status = NT_STATUS_LOGON_FAILURE;
420 }
421
422 cli_ulogoff(cli);
423
424 if (NT_STATUS_IS_OK(nt_status)) {
425 fstring real_username;
426 struct passwd *pass;
427
428 if ( (pass = smb_getpwnam( NULL, user_info->internal_username,
429 real_username, True )) != NULL )
430 {
431 /* if a real user check pam account restrictions */
432 /* only really perfomed if "obey pam restriction" is true */
433 nt_status = smb_pam_accountcheck(pass->pw_name);
434 if ( !NT_STATUS_IS_OK(nt_status)) {
435 DEBUG(1, ("PAM account restriction prevents user login\n"));
436 } else {
437
438 nt_status = make_server_info_pw(server_info, pass->pw_name, pass);
439 }
440 TALLOC_FREE(pass);
441 }
442 else
443 {
444 nt_status = NT_STATUS_NO_SUCH_USER;
445 }
446 }
447
448 if (locally_made_cli) {
449 cli_shutdown(cli);
450 }
451
452 return(nt_status);
453}
454
455static NTSTATUS auth_init_smbserver(struct auth_context *auth_context, const char* param, auth_methods **auth_method)
456{
457 if (!make_auth_methods(auth_context, auth_method)) {
458 return NT_STATUS_NO_MEMORY;
459 }
460 (*auth_method)->name = "smbserver";
461 (*auth_method)->auth = check_smbserver_security;
462 (*auth_method)->get_chal = auth_get_challenge_server;
463 return NT_STATUS_OK;
464}
465
466NTSTATUS auth_server_init(void)
467{
468 return smb_register_auth(AUTH_INTERFACE_VERSION, "smbserver", auth_init_smbserver);
469}
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