source: vendor/3.6.23/source3/auth/auth_server.c

Last change on this file was 740, checked in by Silvan Scherrer, 13 years ago

Samba Server: update vendor to 3.6.0
File size: 14.2 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#include "auth.h"
23#include "system/passwd.h"
24#include "smbd/smbd.h"
25#include "libsmb/libsmb.h"
26
27#undef DBGC_CLASS
28#define DBGC_CLASS DBGC_AUTH
29
30extern userdom_struct current_user_info;
31
32/****************************************************************************
33 Support for server level security.
34****************************************************************************/
35
36static struct cli_state *server_cryptkey(TALLOC_CTX *mem_ctx)
37{
38 struct cli_state *cli = NULL;
39 char *desthost = NULL;
40 struct sockaddr_storage dest_ss;
41 const char *p;
42 char *pserver = NULL;
43 bool connected_ok = False;
44 struct named_mutex *mutex = NULL;
45 NTSTATUS status;
46
47 if (!(cli = cli_initialise()))
48 return NULL;
49
50 /* security = server just can't function with spnego */
51 cli->use_spnego = False;
52
53 pserver = talloc_strdup(mem_ctx, lp_passwordserver());
54 p = pserver;
55
56 while(next_token_talloc(mem_ctx, &p, &desthost, LIST_SEP)) {
57
58 desthost = talloc_sub_basic(mem_ctx,
59 current_user_info.smb_name,
60 current_user_info.domain,
61 desthost);
62 if (!desthost) {
63 return NULL;
64 }
65 strupper_m(desthost);
66
67 if(!resolve_name( desthost, &dest_ss, 0x20, false)) {
68 DEBUG(1,("server_cryptkey: Can't resolve address for %s\n",desthost));
69 continue;
70 }
71
72 if (ismyaddr((struct sockaddr *)&dest_ss)) {
73 DEBUG(1,("Password server loop - disabling password server %s\n",desthost));
74 continue;
75 }
76
77 /* we use a mutex to prevent two connections at once - when a
78 Win2k PDC get two connections where one hasn't completed a
79 session setup yet it will send a TCP reset to the first
80 connection (tridge) */
81
82 mutex = grab_named_mutex(talloc_tos(), desthost, 10);
83 if (mutex == NULL) {
84 cli_shutdown(cli);
85 return NULL;
86 }
87
88 status = cli_connect(cli, desthost, &dest_ss);
89 if (NT_STATUS_IS_OK(status)) {
90 DEBUG(3,("connected to password server %s\n",desthost));
91 connected_ok = True;
92 break;
93 }
94 DEBUG(10,("server_cryptkey: failed to connect to server %s. Error %s\n",
95 desthost, nt_errstr(status) ));
96 TALLOC_FREE(mutex);
97 }
98
99 if (!connected_ok) {
100 DEBUG(0,("password server not available\n"));
101 cli_shutdown(cli);
102 return NULL;
103 }
104
105 if (!attempt_netbios_session_request(&cli, global_myname(),
106 desthost, &dest_ss)) {
107 TALLOC_FREE(mutex);
108 DEBUG(1,("password server fails session request\n"));
109 cli_shutdown(cli);
110 return NULL;
111 }
112
113 if (strequal(desthost,myhostname())) {
114 exit_server_cleanly("Password server loop!");
115 }
116
117 DEBUG(3,("got session\n"));
118
119 status = cli_negprot(cli);
120
121 if (!NT_STATUS_IS_OK(status)) {
122 TALLOC_FREE(mutex);
123 DEBUG(1, ("%s rejected the negprot: %s\n",
124 desthost, nt_errstr(status)));
125 cli_shutdown(cli);
126 return NULL;
127 }
128
129 if (cli->protocol < PROTOCOL_LANMAN2 ||
130 !(cli->sec_mode & NEGOTIATE_SECURITY_USER_LEVEL)) {
131 TALLOC_FREE(mutex);
132 DEBUG(1,("%s isn't in user level security mode\n",desthost));
133 cli_shutdown(cli);
134 return NULL;
135 }
136
137 /* Get the first session setup done quickly, to avoid silly
138 Win2k bugs. (The next connection to the server will kill
139 this one...
140 */
141
142 status = cli_session_setup(cli, "", "", 0, "", 0, "");
143 if (!NT_STATUS_IS_OK(status)) {
144 TALLOC_FREE(mutex);
145 DEBUG(0,("%s rejected the initial session setup (%s)\n",
146 desthost, nt_errstr(status)));
147 cli_shutdown(cli);
148 return NULL;
149 }
150
151 TALLOC_FREE(mutex);
152
153 DEBUG(3,("password server OK\n"));
154
155 return cli;
156}
157
158struct server_security_state {
159 struct cli_state *cli;
160};
161
162/****************************************************************************
163 Send a 'keepalive' packet down the cli pipe.
164****************************************************************************/
165
166static bool send_server_keepalive(const struct timeval *now,
167 void *private_data)
168{
169 struct server_security_state *state = talloc_get_type_abort(
170 private_data, struct server_security_state);
171
172 if (!state->cli || !state->cli->initialised) {
173 return False;
174 }
175
176 if (send_keepalive(state->cli->fd)) {
177 return True;
178 }
179
180 DEBUG( 2, ( "send_server_keepalive: password server keepalive "
181 "failed.\n"));
182 cli_shutdown(state->cli);
183 state->cli = NULL;
184 return False;
185}
186
187static int destroy_server_security(struct server_security_state *state)
188{
189 if (state->cli) {
190 cli_shutdown(state->cli);
191 }
192 return 0;
193}
194
195static struct server_security_state *make_server_security_state(struct cli_state *cli)
196{
197 struct server_security_state *result;
198
199 if (!(result = talloc(NULL, struct server_security_state))) {
200 DEBUG(0, ("talloc failed\n"));
201 cli_shutdown(cli);
202 return NULL;
203 }
204
205 result->cli = cli;
206 talloc_set_destructor(result, destroy_server_security);
207
208 if (lp_keepalive() != 0) {
209 struct timeval interval;
210 interval.tv_sec = lp_keepalive();
211 interval.tv_usec = 0;
212
213 if (event_add_idle(server_event_context(), result, interval,
214 "server_security_keepalive",
215 send_server_keepalive,
216 result) == NULL) {
217 DEBUG(0, ("event_add_idle failed\n"));
218 TALLOC_FREE(result);
219 return NULL;
220 }
221 }
222
223 return result;
224}
225
226/****************************************************************************
227 Get the challenge out of a password server.
228****************************************************************************/
229
230static DATA_BLOB auth_get_challenge_server(const struct auth_context *auth_context,
231 void **my_private_data,
232 TALLOC_CTX *mem_ctx)
233{
234 struct cli_state *cli = server_cryptkey(mem_ctx);
235
236 if (cli) {
237 DEBUG(3,("using password server validation\n"));
238
239 if ((cli->sec_mode & NEGOTIATE_SECURITY_CHALLENGE_RESPONSE) == 0) {
240 /* We can't work with unencrypted password servers
241 unless 'encrypt passwords = no' */
242 DEBUG(5,("make_auth_info_server: Server is unencrypted, no challenge available..\n"));
243
244 /* However, it is still a perfectly fine connection
245 to pass that unencrypted password over */
246 *my_private_data =
247 (void *)make_server_security_state(cli);
248 return data_blob_null;
249 } else if (cli->secblob.length < 8) {
250 /* We can't do much if we don't get a full challenge */
251 DEBUG(2,("make_auth_info_server: Didn't receive a full challenge from server\n"));
252 cli_shutdown(cli);
253 return data_blob_null;
254 }
255
256 if (!(*my_private_data = (void *)make_server_security_state(cli))) {
257 return data_blob(NULL,0);
258 }
259
260 /* The return must be allocated on the caller's mem_ctx, as our own will be
261 destoyed just after the call. */
262 return data_blob_talloc((TALLOC_CTX *)auth_context, cli->secblob.data,8);
263 } else {
264 return data_blob_null;
265 }
266}
267
268
269/****************************************************************************
270 Check for a valid username and password in security=server mode.
271 - Validate a password with the password server.
272****************************************************************************/
273
274static NTSTATUS check_smbserver_security(const struct auth_context *auth_context,
275 void *my_private_data,
276 TALLOC_CTX *mem_ctx,
277 const struct auth_usersupplied_info *user_info,
278 struct auth_serversupplied_info **server_info)
279{
280 struct server_security_state *state = NULL;
281 struct cli_state *cli = NULL;
282 static bool tested_password_server = False;
283 static bool bad_password_server = False;
284 NTSTATUS nt_status = NT_STATUS_NOT_IMPLEMENTED;
285 bool locally_made_cli = False;
286
287 DEBUG(10, ("check_smbserver_security: Check auth for: [%s]\n",
288 user_info->mapped.account_name));
289
290 if (my_private_data == NULL) {
291 DEBUG(10,("check_smbserver_security: "
292 "password server is not connected\n"));
293 return NT_STATUS_LOGON_FAILURE;
294 }
295
296 state = talloc_get_type_abort(my_private_data, struct server_security_state);
297 cli = state->cli;
298
299 if (cli) {
300 } else {
301 cli = server_cryptkey(mem_ctx);
302 locally_made_cli = True;
303 }
304
305 if (!cli || !cli->initialised) {
306 DEBUG(1,("password server is not connected (cli not initialised)\n"));
307 return NT_STATUS_LOGON_FAILURE;
308 }
309
310 if ((cli->sec_mode & NEGOTIATE_SECURITY_CHALLENGE_RESPONSE) == 0) {
311 if (user_info->password_state != AUTH_PASSWORD_PLAIN) {
312 DEBUG(1,("password server %s is plaintext, but we are encrypted. This just can't work :-(\n", cli->desthost));
313 return NT_STATUS_LOGON_FAILURE;
314 }
315 } else {
316 if (memcmp(cli->secblob.data, auth_context->challenge.data, 8) != 0) {
317 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));
318 return NT_STATUS_LOGON_FAILURE;
319 }
320 }
321
322 /*
323 * Attempt a session setup with a totally incorrect password.
324 * If this succeeds with the guest bit *NOT* set then the password
325 * server is broken and is not correctly setting the guest bit. We
326 * need to detect this as some versions of NT4.x are broken. JRA.
327 */
328
329 /* I sure as hell hope that there aren't servers out there that take
330 * NTLMv2 and have this bug, as we don't test for that...
331 * - abartlet@samba.org
332 */
333
334 if ((!tested_password_server) && (lp_paranoid_server_security())) {
335 unsigned char badpass[24];
336 char *baduser = NULL;
337
338 memset(badpass, 0x1f, sizeof(badpass));
339
340 if((user_info->password.response.nt.length == sizeof(badpass)) &&
341 !memcmp(badpass, user_info->password.response.nt.data, sizeof(badpass))) {
342 /*
343 * Very unlikely, our random bad password is the same as the users
344 * password.
345 */
346 memset(badpass, badpass[0]+1, sizeof(badpass));
347 }
348
349 baduser = talloc_asprintf(mem_ctx,
350 "%s%s",
351 INVALID_USER_PREFIX,
352 global_myname());
353 if (!baduser) {
354 return NT_STATUS_NO_MEMORY;
355 }
356
357 if (NT_STATUS_IS_OK(cli_session_setup(cli, baduser,
358 (char *)badpass,
359 sizeof(badpass),
360 (char *)badpass,
361 sizeof(badpass),
362 user_info->mapped.domain_name))) {
363
364 /*
365 * We connected to the password server so we
366 * can say we've tested it.
367 */
368 tested_password_server = True;
369
370 if ((SVAL(cli->inbuf,smb_vwv2) & 1) == 0) {
371 DEBUG(0,("server_validate: password server %s allows users as non-guest \
372with a bad password.\n", cli->desthost));
373 DEBUG(0,("server_validate: This is broken (and insecure) behaviour. Please do not \
374use this machine as the password server.\n"));
375 cli_ulogoff(cli);
376
377 /*
378 * Password server has the bug.
379 */
380 bad_password_server = True;
381 return NT_STATUS_LOGON_FAILURE;
382 }
383 cli_ulogoff(cli);
384 }
385 } else {
386
387 /*
388 * We have already tested the password server.
389 * Fail immediately if it has the bug.
390 */
391
392 if(bad_password_server) {
393 DEBUG(0,("server_validate: [1] password server %s allows users as non-guest \
394with a bad password.\n", cli->desthost));
395 DEBUG(0,("server_validate: [1] This is broken (and insecure) behaviour. Please do not \
396use this machine as the password server.\n"));
397 return NT_STATUS_LOGON_FAILURE;
398 }
399 }
400
401 /*
402 * Now we know the password server will correctly set the guest bit, or is
403 * not guest enabled, we can try with the real password.
404 */
405 switch (user_info->password_state) {
406 case AUTH_PASSWORD_PLAIN:
407 /* Plaintext available */
408 nt_status = cli_session_setup(
409 cli, user_info->client.account_name,
410 user_info->password.plaintext,
411 strlen(user_info->password.plaintext),
412 NULL, 0, user_info->mapped.domain_name);
413 break;
414
415 /* currently the hash values include a challenge-response as well */
416 case AUTH_PASSWORD_HASH:
417 case AUTH_PASSWORD_RESPONSE:
418 nt_status = cli_session_setup(
419 cli, user_info->client.account_name,
420 (char *)user_info->password.response.lanman.data,
421 user_info->password.response.lanman.length,
422 (char *)user_info->password.response.nt.data,
423 user_info->password.response.nt.length,
424 user_info->mapped.domain_name);
425 break;
426 default:
427 DEBUG(0,("user_info constructed for user '%s' was invalid - password_state=%u invalid.\n",user_info->mapped.account_name, user_info->password_state));
428 nt_status = NT_STATUS_INTERNAL_ERROR;
429 }
430
431 if (!NT_STATUS_IS_OK(nt_status)) {
432 DEBUG(1,("password server %s rejected the password: %s\n",
433 cli->desthost, nt_errstr(nt_status)));
434 }
435
436 /* if logged in as guest then reject */
437 if (cli->is_guestlogin) {
438 DEBUG(1,("password server %s gave us guest only\n", cli->desthost));
439 nt_status = NT_STATUS_LOGON_FAILURE;
440 }
441
442 cli_ulogoff(cli);
443
444 if (NT_STATUS_IS_OK(nt_status)) {
445 char *real_username = NULL;
446 struct passwd *pass = NULL;
447
448 if ( (pass = smb_getpwnam(talloc_tos(), user_info->mapped.account_name,
449 &real_username, True )) != NULL )
450 {
451 nt_status = make_server_info_pw(server_info, pass->pw_name, pass);
452 TALLOC_FREE(pass);
453 TALLOC_FREE(real_username);
454 }
455 else
456 {
457 nt_status = NT_STATUS_NO_SUCH_USER;
458 }
459 }
460
461 if (locally_made_cli) {
462 cli_shutdown(cli);
463 }
464
465 return(nt_status);
466}
467
468static NTSTATUS auth_init_smbserver(struct auth_context *auth_context, const char* param, auth_methods **auth_method)
469{
470 struct auth_methods *result;
471
472 result = TALLOC_ZERO_P(auth_context, struct auth_methods);
473 if (result == NULL) {
474 return NT_STATUS_NO_MEMORY;
475 }
476 result->name = "smbserver";
477 result->auth = check_smbserver_security;
478 result->get_chal = auth_get_challenge_server;
479
480 *auth_method = result;
481 return NT_STATUS_OK;
482}
483
484NTSTATUS auth_server_init(void)
485{
486 return smb_register_auth(AUTH_INTERFACE_VERSION, "smbserver", auth_init_smbserver);
487}
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