source: branches/samba-3.3.x/source/auth/auth_server.c

Last change on this file was 206, checked in by Herwig Bauernfeind, 16 years ago

Import Samba 3.3 branch at 3.0.0 level (psmedley's port)
File size: 12.9 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
42 if (!(cli = cli_initialise()))
43 return NULL;
44
45 /* security = server just can't function with spnego */
46 cli->use_spnego = False;
47
48 pserver = talloc_strdup(mem_ctx, lp_passwordserver());
49 p = pserver;
50
51 while(next_token_talloc(mem_ctx, &p, &desthost, LIST_SEP)) {
52 NTSTATUS status;
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)) {
64 DEBUG(1,("server_cryptkey: Can't resolve address for %s\n",desthost));
65 continue;
66 }
67
68 if (ismyaddr(&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 if (!cli_negprot(cli)) {
116 TALLOC_FREE(mutex);
117 DEBUG(1,("%s rejected the negprot\n",desthost));
118 cli_shutdown(cli);
119 return NULL;
120 }
121
122 if (cli->protocol < PROTOCOL_LANMAN2 ||
123 !(cli->sec_mode & NEGOTIATE_SECURITY_USER_LEVEL)) {
124 TALLOC_FREE(mutex);
125 DEBUG(1,("%s isn't in user level security mode\n",desthost));
126 cli_shutdown(cli);
127 return NULL;
128 }
129
130 /* Get the first session setup done quickly, to avoid silly
131 Win2k bugs. (The next connection to the server will kill
132 this one...
133 */
134
135 if (!NT_STATUS_IS_OK(cli_session_setup(cli, "", "", 0, "", 0,
136 ""))) {
137 TALLOC_FREE(mutex);
138 DEBUG(0,("%s rejected the initial session setup (%s)\n",
139 desthost, cli_errstr(cli)));
140 cli_shutdown(cli);
141 return NULL;
142 }
143
144 TALLOC_FREE(mutex);
145
146 DEBUG(3,("password server OK\n"));
147
148 return cli;
149}
150
151struct server_security_state {
152 struct cli_state *cli;
153};
154
155/****************************************************************************
156 Send a 'keepalive' packet down the cli pipe.
157****************************************************************************/
158
159static bool send_server_keepalive(const struct timeval *now,
160 void *private_data)
161{
162 struct server_security_state *state = talloc_get_type_abort(
163 private_data, struct server_security_state);
164
165 if (!state->cli || !state->cli->initialised) {
166 return False;
167 }
168
169 if (send_keepalive(state->cli->fd)) {
170 return True;
171 }
172
173 DEBUG( 2, ( "send_server_keepalive: password server keepalive "
174 "failed.\n"));
175 cli_shutdown(state->cli);
176 state->cli = NULL;
177 return False;
178}
179
180static int destroy_server_security(struct server_security_state *state)
181{
182 if (state->cli) {
183 cli_shutdown(state->cli);
184 }
185 return 0;
186}
187
188static struct server_security_state *make_server_security_state(struct cli_state *cli)
189{
190 struct server_security_state *result;
191
192 if (!(result = talloc(NULL, struct server_security_state))) {
193 DEBUG(0, ("talloc failed\n"));
194 cli_shutdown(cli);
195 return NULL;
196 }
197
198 result->cli = cli;
199 talloc_set_destructor(result, destroy_server_security);
200
201 if (lp_keepalive() != 0) {
202 struct timeval interval;
203 interval.tv_sec = lp_keepalive();
204 interval.tv_usec = 0;
205
206 if (event_add_idle(smbd_event_context(), result, interval,
207 "server_security_keepalive",
208 send_server_keepalive,
209 result) == NULL) {
210 DEBUG(0, ("event_add_idle failed\n"));
211 TALLOC_FREE(result);
212 return NULL;
213 }
214 }
215
216 return result;
217}
218
219/****************************************************************************
220 Get the challenge out of a password server.
221****************************************************************************/
222
223static DATA_BLOB auth_get_challenge_server(const struct auth_context *auth_context,
224 void **my_private_data,
225 TALLOC_CTX *mem_ctx)
226{
227 struct cli_state *cli = server_cryptkey(mem_ctx);
228
229 if (cli) {
230 DEBUG(3,("using password server validation\n"));
231
232 if ((cli->sec_mode & NEGOTIATE_SECURITY_CHALLENGE_RESPONSE) == 0) {
233 /* We can't work with unencrypted password servers
234 unless 'encrypt passwords = no' */
235 DEBUG(5,("make_auth_info_server: Server is unencrypted, no challenge available..\n"));
236
237 /* However, it is still a perfectly fine connection
238 to pass that unencrypted password over */
239 *my_private_data =
240 (void *)make_server_security_state(cli);
241 return data_blob_null;
242 } else if (cli->secblob.length < 8) {
243 /* We can't do much if we don't get a full challenge */
244 DEBUG(2,("make_auth_info_server: Didn't receive a full challenge from server\n"));
245 cli_shutdown(cli);
246 return data_blob_null;
247 }
248
249 if (!(*my_private_data = (void *)make_server_security_state(cli))) {
250 return data_blob(NULL,0);
251 }
252
253 /* The return must be allocated on the caller's mem_ctx, as our own will be
254 destoyed just after the call. */
255 return data_blob_talloc(auth_context->mem_ctx, cli->secblob.data,8);
256 } else {
257 return data_blob_null;
258 }
259}
260
261
262/****************************************************************************
263 Check for a valid username and password in security=server mode.
264 - Validate a password with the password server.
265****************************************************************************/
266
267static NTSTATUS check_smbserver_security(const struct auth_context *auth_context,
268 void *my_private_data,
269 TALLOC_CTX *mem_ctx,
270 const auth_usersupplied_info *user_info,
271 auth_serversupplied_info **server_info)
272{
273 struct server_security_state *state = talloc_get_type_abort(
274 my_private_data, struct server_security_state);
275 struct cli_state *cli;
276 static bool tested_password_server = False;
277 static bool bad_password_server = False;
278 NTSTATUS nt_status = NT_STATUS_NOT_IMPLEMENTED;
279 bool locally_made_cli = False;
280
281 cli = state->cli;
282
283 if (cli) {
284 } else {
285 cli = server_cryptkey(mem_ctx);
286 locally_made_cli = True;
287 }
288
289 if (!cli || !cli->initialised) {
290 DEBUG(1,("password server is not connected (cli not initialised)\n"));
291 return NT_STATUS_LOGON_FAILURE;
292 }
293
294 if ((cli->sec_mode & NEGOTIATE_SECURITY_CHALLENGE_RESPONSE) == 0) {
295 if (user_info->encrypted) {
296 DEBUG(1,("password server %s is plaintext, but we are encrypted. This just can't work :-(\n", cli->desthost));
297 return NT_STATUS_LOGON_FAILURE;
298 }
299 } else {
300 if (memcmp(cli->secblob.data, auth_context->challenge.data, 8) != 0) {
301 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));
302 return NT_STATUS_LOGON_FAILURE;
303 }
304 }
305
306 /*
307 * Attempt a session setup with a totally incorrect password.
308 * If this succeeds with the guest bit *NOT* set then the password
309 * server is broken and is not correctly setting the guest bit. We
310 * need to detect this as some versions of NT4.x are broken. JRA.
311 */
312
313 /* I sure as hell hope that there aren't servers out there that take
314 * NTLMv2 and have this bug, as we don't test for that...
315 * - abartlet@samba.org
316 */
317
318 if ((!tested_password_server) && (lp_paranoid_server_security())) {
319 unsigned char badpass[24];
320 char *baduser = NULL;
321
322 memset(badpass, 0x1f, sizeof(badpass));
323
324 if((user_info->nt_resp.length == sizeof(badpass)) &&
325 !memcmp(badpass, user_info->nt_resp.data, sizeof(badpass))) {
326 /*
327 * Very unlikely, our random bad password is the same as the users
328 * password.
329 */
330 memset(badpass, badpass[0]+1, sizeof(badpass));
331 }
332
333 baduser = talloc_asprintf(mem_ctx,
334 "%s%s",
335 INVALID_USER_PREFIX,
336 global_myname());
337 if (!baduser) {
338 return NT_STATUS_NO_MEMORY;
339 }
340
341 if (NT_STATUS_IS_OK(cli_session_setup(cli, baduser,
342 (char *)badpass,
343 sizeof(badpass),
344 (char *)badpass,
345 sizeof(badpass),
346 user_info->domain))) {
347
348 /*
349 * We connected to the password server so we
350 * can say we've tested it.
351 */
352 tested_password_server = True;
353
354 if ((SVAL(cli->inbuf,smb_vwv2) & 1) == 0) {
355 DEBUG(0,("server_validate: password server %s allows users as non-guest \
356with a bad password.\n", cli->desthost));
357 DEBUG(0,("server_validate: This is broken (and insecure) behaviour. Please do not \
358use this machine as the password server.\n"));
359 cli_ulogoff(cli);
360
361 /*
362 * Password server has the bug.
363 */
364 bad_password_server = True;
365 return NT_STATUS_LOGON_FAILURE;
366 }
367 cli_ulogoff(cli);
368 }
369 } else {
370
371 /*
372 * We have already tested the password server.
373 * Fail immediately if it has the bug.
374 */
375
376 if(bad_password_server) {
377 DEBUG(0,("server_validate: [1] password server %s allows users as non-guest \
378with a bad password.\n", cli->desthost));
379 DEBUG(0,("server_validate: [1] This is broken (and insecure) behaviour. Please do not \
380use this machine as the password server.\n"));
381 return NT_STATUS_LOGON_FAILURE;
382 }
383 }
384
385 /*
386 * Now we know the password server will correctly set the guest bit, or is
387 * not guest enabled, we can try with the real password.
388 */
389
390 if (!user_info->encrypted) {
391 /* Plaintext available */
392 nt_status = cli_session_setup(
393 cli, user_info->smb_name,
394 (char *)user_info->plaintext_password.data,
395 user_info->plaintext_password.length,
396 NULL, 0, user_info->domain);
397
398 } else {
399 nt_status = cli_session_setup(
400 cli, user_info->smb_name,
401 (char *)user_info->lm_resp.data,
402 user_info->lm_resp.length,
403 (char *)user_info->nt_resp.data,
404 user_info->nt_resp.length,
405 user_info->domain);
406 }
407
408 if (!NT_STATUS_IS_OK(nt_status)) {
409 DEBUG(1,("password server %s rejected the password: %s\n",
410 cli->desthost, nt_errstr(nt_status)));
411 }
412
413 /* if logged in as guest then reject */
414 if ((SVAL(cli->inbuf,smb_vwv2) & 1) != 0) {
415 DEBUG(1,("password server %s gave us guest only\n", cli->desthost));
416 nt_status = NT_STATUS_LOGON_FAILURE;
417 }
418
419 cli_ulogoff(cli);
420
421 if (NT_STATUS_IS_OK(nt_status)) {
422 fstring real_username;
423 struct passwd *pass;
424
425 if ( (pass = smb_getpwnam( NULL, user_info->internal_username,
426 real_username, True )) != NULL )
427 {
428 /* if a real user check pam account restrictions */
429 /* only really perfomed if "obey pam restriction" is true */
430 nt_status = smb_pam_accountcheck(pass->pw_name);
431 if ( !NT_STATUS_IS_OK(nt_status)) {
432 DEBUG(1, ("PAM account restriction prevents user login\n"));
433 } else {
434
435 nt_status = make_server_info_pw(server_info, pass->pw_name, pass);
436 }
437 TALLOC_FREE(pass);
438 }
439 else
440 {
441 nt_status = NT_STATUS_NO_SUCH_USER;
442 }
443 }
444
445 if (locally_made_cli) {
446 cli_shutdown(cli);
447 }
448
449 return(nt_status);
450}
451
452static NTSTATUS auth_init_smbserver(struct auth_context *auth_context, const char* param, auth_methods **auth_method)
453{
454 if (!make_auth_methods(auth_context, auth_method)) {
455 return NT_STATUS_NO_MEMORY;
456 }
457 (*auth_method)->name = "smbserver";
458 (*auth_method)->auth = check_smbserver_security;
459 (*auth_method)->get_chal = auth_get_challenge_server;
460 return NT_STATUS_OK;
461}
462
463NTSTATUS auth_server_init(void)
464{
465 return smb_register_auth(AUTH_INTERFACE_VERSION, "smbserver", auth_init_smbserver);
466}
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