ebfffb7d57ead87d83843ff787d8088c406f1dc3
[ira/wip.git] / source3 / smbd / session.c
1 /* 
2    Unix SMB/CIFS implementation.
3    session handling for utmp and PAM
4
5    Copyright (C) tridge@samba.org       2001
6    Copyright (C) abartlet@samba.org     2001
7    Copyright (C) Gerald (Jerry) Carter  2006   
8    
9    This program is free software; you can redistribute it and/or modify
10    it under the terms of the GNU General Public License as published by
11    the Free Software Foundation; either version 3 of the License, or
12    (at your option) any later version.
13    
14    This program is distributed in the hope that it will be useful,
15    but WITHOUT ANY WARRANTY; without even the implied warranty of
16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17    GNU General Public License for more details.
18    
19    You should have received a copy of the GNU General Public License
20    along with this program.  If not, see <http://www.gnu.org/licenses/>.
21 */
22
23 /* a "session" is claimed when we do a SessionSetupX operation
24    and is yielded when the corresponding vuid is destroyed.
25
26    sessions are used to populate utmp and PAM session structures
27 */
28
29 #include "includes.h"
30 #include "smbd/globals.h"
31
32 /********************************************************************
33 ********************************************************************/
34
35 static struct db_context *session_db_ctx(void)
36 {
37         if (session_db_ctx_ptr)
38                 return session_db_ctx_ptr;
39
40         session_db_ctx_ptr = db_open(NULL, lock_path("sessionid.tdb"), 0,
41                                      TDB_CLEAR_IF_FIRST|TDB_DEFAULT,
42                                      O_RDWR | O_CREAT, 0644);
43         return session_db_ctx_ptr;
44 }
45
46 bool session_init(void)
47 {
48         if (session_db_ctx() == NULL) {
49                 DEBUG(1,("session_init: failed to open sessionid tdb\n"));
50                 return False;
51         }
52
53         return True;
54 }
55
56 /********************************************************************
57  called when a session is created
58 ********************************************************************/
59
60 bool session_claim(user_struct *vuser)
61 {
62         TDB_DATA key, data;
63         int i = 0;
64         struct sessionid sessionid;
65         struct server_id pid = procid_self();
66         fstring keystr;
67         const char * hostname;
68         struct db_context *ctx;
69         struct db_record *rec;
70         NTSTATUS status;
71         char addr[INET6_ADDRSTRLEN];
72
73         vuser->session_keystr = NULL;
74
75         /* don't register sessions for the guest user - its just too
76            expensive to go through pam session code for browsing etc */
77         if (vuser->server_info->guest) {
78                 return True;
79         }
80
81         if (!(ctx = session_db_ctx())) {
82                 return False;
83         }
84
85         ZERO_STRUCT(sessionid);
86
87         data.dptr = NULL;
88         data.dsize = 0;
89
90         if (lp_utmp()) {
91
92                 for (i=1;i<MAX_SESSION_ID;i++) {
93
94                         /*
95                          * This is very inefficient and needs fixing -- vl
96                          */
97
98                         struct server_id sess_pid;
99
100                         snprintf(keystr, sizeof(keystr), "ID/%d", i);
101                         key = string_term_tdb_data(keystr);
102
103                         rec = ctx->fetch_locked(ctx, NULL, key);
104
105                         if (rec == NULL) {
106                                 DEBUG(1, ("Could not lock \"%s\"\n", keystr));
107                                 return False;
108                         }
109
110                         if (rec->value.dsize != sizeof(sessionid)) {
111                                 DEBUG(1, ("Re-using invalid record\n"));
112                                 break;
113                         }
114
115                         memcpy(&sess_pid,
116                                ((char *)rec->value.dptr)
117                                + offsetof(struct sessionid, pid),
118                                sizeof(sess_pid));
119
120                         if (!process_exists(sess_pid)) {
121                                 DEBUG(5, ("%s has died -- re-using session\n",
122                                           procid_str_static(&sess_pid)));
123                                 break;
124                         }
125
126                         TALLOC_FREE(rec);
127                 }
128
129                 if (i == MAX_SESSION_ID) {
130                         SMB_ASSERT(rec == NULL);
131                         DEBUG(1,("session_claim: out of session IDs "
132                                  "(max is %d)\n", MAX_SESSION_ID));
133                         return False;
134                 }
135
136                 snprintf(sessionid.id_str, sizeof(sessionid.id_str),
137                          SESSION_UTMP_TEMPLATE, i);
138         } else
139         {
140                 snprintf(keystr, sizeof(keystr), "ID/%s/%u",
141                          procid_str_static(&pid), vuser->vuid);
142                 key = string_term_tdb_data(keystr);
143
144                 rec = ctx->fetch_locked(ctx, NULL, key);
145
146                 if (rec == NULL) {
147                         DEBUG(1, ("Could not lock \"%s\"\n", keystr));
148                         return False;
149                 }
150
151                 snprintf(sessionid.id_str, sizeof(sessionid.id_str),
152                          SESSION_TEMPLATE, (long unsigned int)sys_getpid(),
153                          vuser->vuid);
154         }
155
156         SMB_ASSERT(rec != NULL);
157
158         /* If 'hostname lookup' == yes, then do the DNS lookup.  This is
159            needed because utmp and PAM both expect DNS names
160
161            client_name() handles this case internally.
162         */
163
164         hostname = client_name(get_client_fd());
165         if (strcmp(hostname, "UNKNOWN") == 0) {
166                 hostname = client_addr(get_client_fd(),addr,sizeof(addr));
167         }
168
169         fstrcpy(sessionid.username, vuser->server_info->unix_name);
170         fstrcpy(sessionid.hostname, hostname);
171         sessionid.id_num = i;  /* Only valid for utmp sessions */
172         sessionid.pid = pid;
173         sessionid.uid = vuser->server_info->utok.uid;
174         sessionid.gid = vuser->server_info->utok.gid;
175         fstrcpy(sessionid.remote_machine, get_remote_machine_name());
176         fstrcpy(sessionid.ip_addr_str,
177                 client_addr(get_client_fd(),addr,sizeof(addr)));
178         sessionid.connect_start = time(NULL);
179
180         if (!smb_pam_claim_session(sessionid.username, sessionid.id_str,
181                                    sessionid.hostname)) {
182                 DEBUG(1,("pam_session rejected the session for %s [%s]\n",
183                                 sessionid.username, sessionid.id_str));
184
185                 TALLOC_FREE(rec);
186                 return False;
187         }
188
189         data.dptr = (uint8 *)&sessionid;
190         data.dsize = sizeof(sessionid);
191
192         status = rec->store(rec, data, TDB_REPLACE);
193
194         TALLOC_FREE(rec);
195
196         if (!NT_STATUS_IS_OK(status)) {
197                 DEBUG(1,("session_claim: unable to create session id "
198                          "record: %s\n", nt_errstr(status)));
199                 return False;
200         }
201
202         if (lp_utmp()) {
203                 sys_utmp_claim(sessionid.username, sessionid.hostname,
204                                sessionid.ip_addr_str,
205                                sessionid.id_str, sessionid.id_num);
206         }
207
208         vuser->session_keystr = talloc_strdup(vuser, keystr);
209         if (!vuser->session_keystr) {
210                 DEBUG(0, ("session_claim:  talloc_strdup() failed for session_keystr\n"));
211                 return False;
212         }
213         return True;
214 }
215
216 /********************************************************************
217  called when a session is destroyed
218 ********************************************************************/
219
220 void session_yield(user_struct *vuser)
221 {
222         TDB_DATA key;
223         struct sessionid sessionid;
224         struct db_context *ctx;
225         struct db_record *rec;
226
227         if (!(ctx = session_db_ctx())) return;
228
229         if (!vuser->session_keystr) {
230                 return;
231         }
232
233         key = string_term_tdb_data(vuser->session_keystr);
234
235         if (!(rec = ctx->fetch_locked(ctx, NULL, key))) {
236                 return;
237         }
238
239         if (rec->value.dsize != sizeof(sessionid))
240                 return;
241
242         memcpy(&sessionid, rec->value.dptr, sizeof(sessionid));
243
244         if (lp_utmp()) {
245                 sys_utmp_yield(sessionid.username, sessionid.hostname, 
246                                sessionid.ip_addr_str,
247                                sessionid.id_str, sessionid.id_num);
248         }
249
250         smb_pam_close_session(sessionid.username, sessionid.id_str,
251                               sessionid.hostname);
252
253         rec->delete_rec(rec);
254
255         TALLOC_FREE(rec);
256 }
257
258 /********************************************************************
259 ********************************************************************/
260
261 static bool session_traverse(int (*fn)(struct db_record *db,
262                                        void *private_data),
263                              void *private_data)
264 {
265         struct db_context *ctx;
266
267         if (!(ctx = session_db_ctx())) {
268                 DEBUG(3, ("No tdb opened\n"));
269                 return False;
270         }
271
272         ctx->traverse_read(ctx, fn, private_data);
273         return True;
274 }
275
276 /********************************************************************
277 ********************************************************************/
278
279 struct session_list {
280         TALLOC_CTX *mem_ctx;
281         int count;
282         struct sessionid *sessions;
283 };
284
285 static int gather_sessioninfo(struct db_record *rec, void *state)
286 {
287         struct session_list *sesslist = (struct session_list *) state;
288         const struct sessionid *current =
289                 (const struct sessionid *) rec->value.dptr;
290
291         sesslist->sessions = TALLOC_REALLOC_ARRAY(
292                 sesslist->mem_ctx, sesslist->sessions, struct sessionid,
293                 sesslist->count+1);
294
295         if (!sesslist->sessions) {
296                 sesslist->count = 0;
297                 return -1;
298         }
299
300         memcpy(&sesslist->sessions[sesslist->count], current,
301                sizeof(struct sessionid));
302
303         sesslist->count++;
304
305         DEBUG(7,("gather_sessioninfo session from %s@%s\n", 
306                  current->username, current->remote_machine));
307
308         return 0;
309 }
310
311 /********************************************************************
312 ********************************************************************/
313
314 int list_sessions(TALLOC_CTX *mem_ctx, struct sessionid **session_list)
315 {
316         struct session_list sesslist;
317
318         sesslist.mem_ctx = mem_ctx;
319         sesslist.count = 0;
320         sesslist.sessions = NULL;
321         
322         if (!session_traverse(gather_sessioninfo, (void *) &sesslist)) {
323                 DEBUG(3, ("Session traverse failed\n"));
324                 SAFE_FREE(sesslist.sessions);
325                 *session_list = NULL;
326                 return 0;
327         }
328
329         *session_list = sesslist.sessions;
330         return sesslist.count;
331 }