source: branches/samba-3.0/source/auth/auth_server.c

Last change on this file was 124, checked in by Paul Smedley, 17 years ago

Update source to 3.0.28a
File size: 12.7 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 2 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, write to the Free Software
19 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20*/
21
22#include "includes.h"
23
24#undef DBGC_CLASS
25#define DBGC_CLASS DBGC_AUTH
26
27extern userdom_struct current_user_info;
28
29/****************************************************************************
30 Support for server level security.
31****************************************************************************/
32
33static struct cli_state *server_cryptkey(TALLOC_CTX *mem_ctx)
34{
35 struct cli_state *cli = NULL;
36 fstring desthost;
37 struct in_addr dest_ip;
38 const char *p;
39 char *pserver;
40 BOOL connected_ok = False;
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( &p, desthost, LIST_SEP, sizeof(desthost))) {
52 NTSTATUS status;
53
54 standard_sub_basic(current_user_info.smb_name, current_user_info.domain,
55 desthost, sizeof(desthost));
56 strupper_m(desthost);
57
58 if(!resolve_name( desthost, &dest_ip, 0x20)) {
59 DEBUG(1,("server_cryptkey: Can't resolve address for %s\n",desthost));
60 continue;
61 }
62
63 if (ismyip(dest_ip)) {
64 DEBUG(1,("Password server loop - disabling password server %s\n",desthost));
65 continue;
66 }
67
68 /* we use a mutex to prevent two connections at once - when a
69 Win2k PDC get two connections where one hasn't completed a
70 session setup yet it will send a TCP reset to the first
71 connection (tridge) */
72
73 if (!grab_server_mutex(desthost)) {
74 cli_shutdown(cli);
75 return NULL;
76 }
77
78 status = cli_connect(cli, desthost, &dest_ip);
79 if (NT_STATUS_IS_OK(status)) {
80 DEBUG(3,("connected to password server %s\n",desthost));
81 connected_ok = True;
82 break;
83 }
84 DEBUG(10,("server_cryptkey: failed to connect to server %s. Error %s\n",
85 desthost, nt_errstr(status) ));
86 }
87
88 if (!connected_ok) {
89 release_server_mutex();
90 DEBUG(0,("password server not available\n"));
91 cli_shutdown(cli);
92 return NULL;
93 }
94
95 if (!attempt_netbios_session_request(&cli, global_myname(),
96 desthost, &dest_ip)) {
97 release_server_mutex();
98 DEBUG(1,("password server fails session request\n"));
99 cli_shutdown(cli);
100 return NULL;
101 }
102
103 if (strequal(desthost,myhostname())) {
104 exit_server_cleanly("Password server loop!");
105 }
106
107 DEBUG(3,("got session\n"));
108
109 if (!cli_negprot(cli)) {
110 DEBUG(1,("%s rejected the negprot\n",desthost));
111 release_server_mutex();
112 cli_shutdown(cli);
113 return NULL;
114 }
115
116 if (cli->protocol < PROTOCOL_LANMAN2 ||
117 !(cli->sec_mode & NEGOTIATE_SECURITY_USER_LEVEL)) {
118 DEBUG(1,("%s isn't in user level security mode\n",desthost));
119 release_server_mutex();
120 cli_shutdown(cli);
121 return NULL;
122 }
123
124 /* Get the first session setup done quickly, to avoid silly
125 Win2k bugs. (The next connection to the server will kill
126 this one...
127 */
128
129 if (!NT_STATUS_IS_OK(cli_session_setup(cli, "", "", 0, "", 0,
130 ""))) {
131 DEBUG(0,("%s rejected the initial session setup (%s)\n",
132 desthost, cli_errstr(cli)));
133 release_server_mutex();
134 cli_shutdown(cli);
135 return NULL;
136 }
137
138 release_server_mutex();
139
140 DEBUG(3,("password server OK\n"));
141
142 return cli;
143}
144
145/****************************************************************************
146 Clean up our allocated cli.
147****************************************************************************/
148
149static void free_server_private_data(void **private_data_pointer)
150{
151 struct cli_state **cli = (struct cli_state **)private_data_pointer;
152 if (*cli && (*cli)->initialised) {
153 DEBUG(10, ("Shutting down smbserver connection\n"));
154 cli_shutdown(*cli);
155 }
156 *private_data_pointer = NULL;
157}
158
159/****************************************************************************
160 Send a 'keepalive' packet down the cli pipe.
161****************************************************************************/
162
163static void send_server_keepalive(void **private_data_pointer)
164{
165 /* also send a keepalive to the password server if its still
166 connected */
167 if (private_data_pointer) {
168 struct cli_state *cli = (struct cli_state *)(*private_data_pointer);
169 if (cli && cli->initialised) {
170 if (!send_keepalive(cli->fd)) {
171 DEBUG( 2, ( "send_server_keepalive: password server keepalive failed.\n"));
172 cli_shutdown(cli);
173 *private_data_pointer = NULL;
174 }
175 }
176 }
177}
178
179/****************************************************************************
180 Get the challenge out of a password server.
181****************************************************************************/
182
183static DATA_BLOB auth_get_challenge_server(const struct auth_context *auth_context,
184 void **my_private_data,
185 TALLOC_CTX *mem_ctx)
186{
187 struct cli_state *cli = server_cryptkey(mem_ctx);
188
189 if (cli) {
190 DEBUG(3,("using password server validation\n"));
191
192 if ((cli->sec_mode & NEGOTIATE_SECURITY_CHALLENGE_RESPONSE) == 0) {
193 /* We can't work with unencrypted password servers
194 unless 'encrypt passwords = no' */
195 DEBUG(5,("make_auth_info_server: Server is unencrypted, no challenge available..\n"));
196
197 /* However, it is still a perfectly fine connection
198 to pass that unencrypted password over */
199 *my_private_data = (void *)cli;
200 return data_blob(NULL, 0);
201
202 } else if (cli->secblob.length < 8) {
203 /* We can't do much if we don't get a full challenge */
204 DEBUG(2,("make_auth_info_server: Didn't receive a full challenge from server\n"));
205 cli_shutdown(cli);
206 return data_blob(NULL, 0);
207 }
208
209 *my_private_data = (void *)cli;
210
211 /* The return must be allocated on the caller's mem_ctx, as our own will be
212 destoyed just after the call. */
213 return data_blob_talloc(auth_context->mem_ctx, cli->secblob.data,8);
214 } else {
215 return data_blob(NULL, 0);
216 }
217}
218
219
220/****************************************************************************
221 Check for a valid username and password in security=server mode.
222 - Validate a password with the password server.
223****************************************************************************/
224
225static NTSTATUS check_smbserver_security(const struct auth_context *auth_context,
226 void *my_private_data,
227 TALLOC_CTX *mem_ctx,
228 const auth_usersupplied_info *user_info,
229 auth_serversupplied_info **server_info)
230{
231 struct cli_state *cli;
232 static unsigned char badpass[24];
233 static fstring baduser;
234 static BOOL tested_password_server = False;
235 static BOOL bad_password_server = False;
236 NTSTATUS nt_status = NT_STATUS_NOT_IMPLEMENTED;
237 BOOL locally_made_cli = False;
238
239 cli = (struct cli_state *)my_private_data;
240
241 if (cli) {
242 } else {
243 cli = server_cryptkey(mem_ctx);
244 locally_made_cli = True;
245 }
246
247 if (!cli || !cli->initialised) {
248 DEBUG(1,("password server is not connected (cli not initilised)\n"));
249 return NT_STATUS_LOGON_FAILURE;
250 }
251
252 if ((cli->sec_mode & NEGOTIATE_SECURITY_CHALLENGE_RESPONSE) == 0) {
253 if (user_info->encrypted) {
254 DEBUG(1,("password server %s is plaintext, but we are encrypted. This just can't work :-(\n", cli->desthost));
255 return NT_STATUS_LOGON_FAILURE;
256 }
257 } else {
258 if (memcmp(cli->secblob.data, auth_context->challenge.data, 8) != 0) {
259 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));
260 return NT_STATUS_LOGON_FAILURE;
261 }
262 }
263
264 if(badpass[0] == 0)
265 memset(badpass, 0x1f, sizeof(badpass));
266
267 if((user_info->nt_resp.length == sizeof(badpass)) &&
268 !memcmp(badpass, user_info->nt_resp.data, sizeof(badpass))) {
269 /*
270 * Very unlikely, our random bad password is the same as the users
271 * password.
272 */
273 memset(badpass, badpass[0]+1, sizeof(badpass));
274 }
275
276 if(baduser[0] == 0) {
277 fstrcpy(baduser, INVALID_USER_PREFIX);
278 fstrcat(baduser, global_myname());
279 }
280
281 /*
282 * Attempt a session setup with a totally incorrect password.
283 * If this succeeds with the guest bit *NOT* set then the password
284 * server is broken and is not correctly setting the guest bit. We
285 * need to detect this as some versions of NT4.x are broken. JRA.
286 */
287
288 /* I sure as hell hope that there aren't servers out there that take
289 * NTLMv2 and have this bug, as we don't test for that...
290 * - abartlet@samba.org
291 */
292
293 if ((!tested_password_server) && (lp_paranoid_server_security())) {
294 if (NT_STATUS_IS_OK(cli_session_setup(cli, baduser,
295 (char *)badpass,
296 sizeof(badpass),
297 (char *)badpass,
298 sizeof(badpass),
299 user_info->domain))) {
300
301 /*
302 * We connected to the password server so we
303 * can say we've tested it.
304 */
305 tested_password_server = True;
306
307 if ((SVAL(cli->inbuf,smb_vwv2) & 1) == 0) {
308 DEBUG(0,("server_validate: password server %s allows users as non-guest \
309with a bad password.\n", cli->desthost));
310 DEBUG(0,("server_validate: This is broken (and insecure) behaviour. Please do not \
311use this machine as the password server.\n"));
312 cli_ulogoff(cli);
313
314 /*
315 * Password server has the bug.
316 */
317 bad_password_server = True;
318 return NT_STATUS_LOGON_FAILURE;
319 }
320 cli_ulogoff(cli);
321 }
322 } else {
323
324 /*
325 * We have already tested the password server.
326 * Fail immediately if it has the bug.
327 */
328
329 if(bad_password_server) {
330 DEBUG(0,("server_validate: [1] password server %s allows users as non-guest \
331with a bad password.\n", cli->desthost));
332 DEBUG(0,("server_validate: [1] This is broken (and insecure) behaviour. Please do not \
333use this machine as the password server.\n"));
334 return NT_STATUS_LOGON_FAILURE;
335 }
336 }
337
338 /*
339 * Now we know the password server will correctly set the guest bit, or is
340 * not guest enabled, we can try with the real password.
341 */
342
343 if (!user_info->encrypted) {
344 /* Plaintext available */
345 nt_status = cli_session_setup(
346 cli, user_info->smb_name,
347 (char *)user_info->plaintext_password.data,
348 user_info->plaintext_password.length,
349 NULL, 0, user_info->domain);
350
351 } else {
352 nt_status = cli_session_setup(
353 cli, user_info->smb_name,
354 (char *)user_info->lm_resp.data,
355 user_info->lm_resp.length,
356 (char *)user_info->nt_resp.data,
357 user_info->nt_resp.length,
358 user_info->domain);
359 }
360
361 if (!NT_STATUS_IS_OK(nt_status)) {
362 DEBUG(1,("password server %s rejected the password: %s\n",
363 cli->desthost, nt_errstr(nt_status)));
364 }
365
366 /* if logged in as guest then reject */
367 if ((SVAL(cli->inbuf,smb_vwv2) & 1) != 0) {
368 DEBUG(1,("password server %s gave us guest only\n", cli->desthost));
369 nt_status = NT_STATUS_LOGON_FAILURE;
370 }
371
372 cli_ulogoff(cli);
373
374 if (NT_STATUS_IS_OK(nt_status)) {
375 fstring real_username;
376 struct passwd *pass;
377
378 if ( (pass = smb_getpwnam( NULL, user_info->internal_username,
379 real_username, True )) != NULL )
380 {
381 /* if a real user check pam account restrictions */
382 /* only really perfomed if "obey pam restriction" is true */
383 nt_status = smb_pam_accountcheck(pass->pw_name);
384 if ( !NT_STATUS_IS_OK(nt_status)) {
385 DEBUG(1, ("PAM account restriction prevents user login\n"));
386 } else {
387
388 nt_status = make_server_info_pw(server_info, pass->pw_name, pass);
389 }
390 TALLOC_FREE(pass);
391 }
392 else
393 {
394 nt_status = NT_STATUS_NO_SUCH_USER;
395 }
396 }
397
398 if (locally_made_cli) {
399 cli_shutdown(cli);
400 }
401
402 return(nt_status);
403}
404
405static NTSTATUS auth_init_smbserver(struct auth_context *auth_context, const char* param, auth_methods **auth_method)
406{
407 if (!make_auth_methods(auth_context, auth_method)) {
408 return NT_STATUS_NO_MEMORY;
409 }
410 (*auth_method)->name = "smbserver";
411 (*auth_method)->auth = check_smbserver_security;
412 (*auth_method)->get_chal = auth_get_challenge_server;
413 (*auth_method)->send_keepalive = send_server_keepalive;
414 (*auth_method)->free_private_data = free_server_private_data;
415 return NT_STATUS_OK;
416}
417
418NTSTATUS auth_server_init(void)
419{
420 return smb_register_auth(AUTH_INTERFACE_VERSION, "smbserver", auth_init_smbserver);
421}
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