r15549: removing rhosts and 'hosts equiv' authentication features
[tprouty/samba.git] / source / auth / auth_server.c
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
27 extern userdom_struct current_user_info;
28
29 /****************************************************************************
30  Support for server level security.
31 ****************************************************************************/
32
33 static 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(cli)))
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                 standard_sub_basic(current_user_info.smb_name, desthost, sizeof(desthost));
53                 strupper_m(desthost);
54
55                 if(!resolve_name( desthost, &dest_ip, 0x20)) {
56                         DEBUG(1,("server_cryptkey: Can't resolve address for %s\n",desthost));
57                         continue;
58                 }
59
60                 if (ismyip(dest_ip)) {
61                         DEBUG(1,("Password server loop - disabling password server %s\n",desthost));
62                         continue;
63                 }
64
65                 /* we use a mutex to prevent two connections at once - when a 
66                    Win2k PDC get two connections where one hasn't completed a 
67                    session setup yet it will send a TCP reset to the first 
68                    connection (tridge) */
69
70                 if (!grab_server_mutex(desthost)) {
71                         return NULL;
72                 }
73
74                 if (cli_connect(cli, desthost, &dest_ip)) {
75                         DEBUG(3,("connected to password server %s\n",desthost));
76                         connected_ok = True;
77                         break;
78                 }
79         }
80
81         if (!connected_ok) {
82                 release_server_mutex();
83                 DEBUG(0,("password server not available\n"));
84                 cli_shutdown(cli);
85                 return NULL;
86         }
87         
88         if (!attempt_netbios_session_request(cli, global_myname(), 
89                                              desthost, &dest_ip)) {
90                 release_server_mutex();
91                 DEBUG(1,("password server fails session request\n"));
92                 cli_shutdown(cli);
93                 return NULL;
94         }
95         
96         if (strequal(desthost,myhostname())) {
97                 exit_server("Password server loop!");
98         }
99         
100         DEBUG(3,("got session\n"));
101
102         if (!cli_negprot(cli)) {
103                 DEBUG(1,("%s rejected the negprot\n",desthost));
104                 release_server_mutex();
105                 cli_shutdown(cli);
106                 return NULL;
107         }
108
109         if (cli->protocol < PROTOCOL_LANMAN2 ||
110             !(cli->sec_mode & NEGOTIATE_SECURITY_USER_LEVEL)) {
111                 DEBUG(1,("%s isn't in user level security mode\n",desthost));
112                 release_server_mutex();
113                 cli_shutdown(cli);
114                 return NULL;
115         }
116
117         /* Get the first session setup done quickly, to avoid silly 
118            Win2k bugs.  (The next connection to the server will kill
119            this one... 
120         */
121
122         if (!cli_session_setup(cli, "", "", 0, "", 0,
123                                "")) {
124                 DEBUG(0,("%s rejected the initial session setup (%s)\n",
125                          desthost, cli_errstr(cli)));
126                 release_server_mutex();
127                 cli_shutdown(cli);
128                 return NULL;
129         }
130         
131         release_server_mutex();
132         
133         DEBUG(3,("password server OK\n"));
134         
135         return cli;
136 }
137
138 /****************************************************************************
139  Clean up our allocated cli.
140 ****************************************************************************/
141
142 static void free_server_private_data(void **private_data_pointer) 
143 {
144         struct cli_state **cli = (struct cli_state **)private_data_pointer;
145         if (*cli && (*cli)->initialised) {
146                 DEBUG(10, ("Shutting down smbserver connection\n"));
147                 cli_shutdown(*cli);
148         }
149         *private_data_pointer = NULL;
150 }
151
152 /****************************************************************************
153  Send a 'keepalive' packet down the cli pipe.
154 ****************************************************************************/
155
156 static void send_server_keepalive(void **private_data_pointer) 
157 {
158         /* also send a keepalive to the password server if its still
159            connected */
160         if (private_data_pointer) {
161                 struct cli_state *cli = (struct cli_state *)(*private_data_pointer);
162                 if (cli && cli->initialised) {
163                         if (!send_keepalive(cli->fd)) {
164                                 DEBUG( 2, ( "send_server_keepalive: password server keepalive failed.\n"));
165                                 cli_shutdown(cli);
166                                 *private_data_pointer = NULL;
167                         }
168                 }
169         }
170 }
171
172 /****************************************************************************
173  Get the challenge out of a password server.
174 ****************************************************************************/
175
176 static DATA_BLOB auth_get_challenge_server(const struct auth_context *auth_context,
177                                            void **my_private_data, 
178                                            TALLOC_CTX *mem_ctx)
179 {
180         struct cli_state *cli = server_cryptkey(mem_ctx);
181         
182         if (cli) {
183                 DEBUG(3,("using password server validation\n"));
184
185                 if ((cli->sec_mode & NEGOTIATE_SECURITY_CHALLENGE_RESPONSE) == 0) {
186                         /* We can't work with unencrypted password servers
187                            unless 'encrypt passwords = no' */
188                         DEBUG(5,("make_auth_info_server: Server is unencrypted, no challenge available..\n"));
189                         
190                         /* However, it is still a perfectly fine connection
191                            to pass that unencrypted password over */
192                         *my_private_data = (void *)cli;
193                         return data_blob(NULL, 0);
194                         
195                 } else if (cli->secblob.length < 8) {
196                         /* We can't do much if we don't get a full challenge */
197                         DEBUG(2,("make_auth_info_server: Didn't receive a full challenge from server\n"));
198                         cli_shutdown(cli);
199                         return data_blob(NULL, 0);
200                 }
201
202                 *my_private_data = (void *)cli;
203
204                 /* The return must be allocated on the caller's mem_ctx, as our own will be
205                    destoyed just after the call. */
206                 return data_blob_talloc(auth_context->mem_ctx, cli->secblob.data,8);
207         } else {
208                 return data_blob(NULL, 0);
209         }
210 }
211
212
213 /****************************************************************************
214  Check for a valid username and password in security=server mode.
215   - Validate a password with the password server.
216 ****************************************************************************/
217
218 static NTSTATUS check_smbserver_security(const struct auth_context *auth_context,
219                                          void *my_private_data, 
220                                          TALLOC_CTX *mem_ctx,
221                                          const auth_usersupplied_info *user_info, 
222                                          auth_serversupplied_info **server_info)
223 {
224         struct cli_state *cli;
225         static unsigned char badpass[24];
226         static fstring baduser; 
227         static BOOL tested_password_server = False;
228         static BOOL bad_password_server = False;
229         NTSTATUS nt_status = NT_STATUS_NOT_IMPLEMENTED;
230         BOOL locally_made_cli = False;
231
232         /* 
233          * Check that the requested domain is not our own machine name.
234          * If it is, we should never check the PDC here, we use our own local
235          * password file.
236          */
237
238         if(is_myname(user_info->domain)) {
239                 DEBUG(3,("check_smbserver_security: Requested domain was for this machine.\n"));
240                 return nt_status;
241         }
242
243         cli = my_private_data;
244         
245         if (cli) {
246         } else {
247                 cli = server_cryptkey(mem_ctx);
248                 locally_made_cli = True;
249         }
250
251         if (!cli || !cli->initialised) {
252                 DEBUG(1,("password server is not connected (cli not initilised)\n"));
253                 return NT_STATUS_LOGON_FAILURE;
254         }  
255         
256         if ((cli->sec_mode & NEGOTIATE_SECURITY_CHALLENGE_RESPONSE) == 0) {
257                 if (user_info->encrypted) {
258                         DEBUG(1,("password server %s is plaintext, but we are encrypted. This just can't work :-(\n", cli->desthost));
259                         return NT_STATUS_LOGON_FAILURE;         
260                 }
261         } else {
262                 if (memcmp(cli->secblob.data, auth_context->challenge.data, 8) != 0) {
263                         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));
264                         return NT_STATUS_LOGON_FAILURE;         
265                 }
266         }
267
268         if(badpass[0] == 0)
269                 memset(badpass, 0x1f, sizeof(badpass));
270
271         if((user_info->nt_resp.length == sizeof(badpass)) && 
272            !memcmp(badpass, user_info->nt_resp.data, sizeof(badpass))) {
273                 /* 
274                  * Very unlikely, our random bad password is the same as the users
275                  * password.
276                  */
277                 memset(badpass, badpass[0]+1, sizeof(badpass));
278         }
279
280         if(baduser[0] == 0) {
281                 fstrcpy(baduser, INVALID_USER_PREFIX);
282                 fstrcat(baduser, global_myname());
283         }
284
285         /*
286          * Attempt a session setup with a totally incorrect password.
287          * If this succeeds with the guest bit *NOT* set then the password
288          * server is broken and is not correctly setting the guest bit. We
289          * need to detect this as some versions of NT4.x are broken. JRA.
290          */
291
292         /* I sure as hell hope that there aren't servers out there that take 
293          * NTLMv2 and have this bug, as we don't test for that... 
294          *  - abartlet@samba.org
295          */
296
297         if ((!tested_password_server) && (lp_paranoid_server_security())) {
298                 if (cli_session_setup(cli, baduser, (char *)badpass, sizeof(badpass), 
299                                         (char *)badpass, sizeof(badpass), 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 \
309 with a bad password.\n", cli->desthost));
310                                 DEBUG(0,("server_validate: This is broken (and insecure) behaviour. Please do not \
311 use 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 \
331 with a bad password.\n", cli->desthost));
332                         DEBUG(0,("server_validate: [1] This is broken (and insecure) behaviour. Please do not \
333 use 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                 if (!cli_session_setup(cli, user_info->smb_name, 
346                                        (char *)user_info->plaintext_password.data, 
347                                        user_info->plaintext_password.length, 
348                                        NULL, 0,
349                                        user_info->domain)) {
350                         DEBUG(1,("password server %s rejected the password\n", cli->desthost));
351                         /* Make this cli_nt_error() when the conversion is in */
352                         nt_status = cli_nt_error(cli);
353                 } else {
354                         nt_status = NT_STATUS_OK;
355                 }
356         } else {
357                 if (!cli_session_setup(cli, user_info->smb_name, 
358                                        (char *)user_info->lm_resp.data, 
359                                        user_info->lm_resp.length, 
360                                        (char *)user_info->nt_resp.data, 
361                                        user_info->nt_resp.length, 
362                                        user_info->domain)) {
363                         DEBUG(1,("password server %s rejected the password\n", cli->desthost));
364                         /* Make this cli_nt_error() when the conversion is in */
365                         nt_status = cli_nt_error(cli);
366                 } else {
367                         nt_status = NT_STATUS_OK;
368                 }
369         }
370
371         /* if logged in as guest then reject */
372         if ((SVAL(cli->inbuf,smb_vwv2) & 1) != 0) {
373                 DEBUG(1,("password server %s gave us guest only\n", cli->desthost));
374                 nt_status = NT_STATUS_LOGON_FAILURE;
375         }
376
377         cli_ulogoff(cli);
378
379         if (NT_STATUS_IS_OK(nt_status)) {
380                 fstring real_username;
381                 struct passwd *pass;
382
383                 if ( (pass = smb_getpwnam( NULL, user_info->internal_username, 
384                         real_username, True )) != NULL ) 
385                 {
386                         nt_status = make_server_info_pw(server_info, pass->pw_name, pass);
387                         TALLOC_FREE(pass);
388                 }
389                 else
390                 {
391                         nt_status = NT_STATUS_NO_SUCH_USER;
392                 }
393         }
394
395         if (locally_made_cli) {
396                 cli_shutdown(cli);
397         }
398
399         return(nt_status);
400 }
401
402 static NTSTATUS auth_init_smbserver(struct auth_context *auth_context, const char* param, auth_methods **auth_method) 
403 {
404         if (!make_auth_methods(auth_context, auth_method)) {
405                 return NT_STATUS_NO_MEMORY;
406         }
407         (*auth_method)->name = "smbserver";
408         (*auth_method)->auth = check_smbserver_security;
409         (*auth_method)->get_chal = auth_get_challenge_server;
410         (*auth_method)->send_keepalive = send_server_keepalive;
411         (*auth_method)->free_private_data = free_server_private_data;
412         return NT_STATUS_OK;
413 }
414
415 NTSTATUS auth_server_init(void)
416 {
417         return smb_register_auth(AUTH_INTERFACE_VERSION, "smbserver", auth_init_smbserver);
418 }