source3/smbd/session.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    session handling for utmp and PAM
   4    Copyright (C) tridge@samba.org 2001
   5    Copyright (C) abartlet@pcug.org.au 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 /* a "session" is claimed when we do a SessionSetupX operation
  23    and is yielded when the corresponding vuid is destroyed.
  24
  25    sessions are used to populate utmp and PAM session structures
  26 */
  27
  28 #include "includes.h"
  29
  30 static TDB_CONTEXT *tdb;
  31
  32 BOOL session_init(void)
  33 {
  34         if (tdb)
  35                 return True;
  36
  37         tdb = tdb_open_ex(lock_path("sessionid.tdb"), 0, TDB_CLEAR_IF_FIRST|TDB_DEFAULT,
  38                        O_RDWR | O_CREAT, 0644, smbd_tdb_log);
  39         if (!tdb) {
  40                 DEBUG(1,("session_init: failed to open sessionid tdb\n"));
  41                 return False;
  42         }
  43
  44         return True;
  45 }
  46
  47 /* called when a session is created */
  48 BOOL session_claim(user_struct *vuser)
  49 {
  50         int i = 0;
  51         TDB_DATA data;
  52         struct sockaddr sa;
  53         struct in_addr *client_ip;
  54         struct sessionid sessionid;
  55         uint32 pid = (uint32)sys_getpid();
  56         TDB_DATA key;
  57         fstring keystr;
  58         char * hostname;
  59         int tdb_store_flag;  /* If using utmp, we do an inital 'lock hold' store,
  60                                 but we don't need this if we are just using the
  61                                 (unique) pid/vuid combination */
  62
  63         vuser->session_keystr = NULL;
  64
  65         /* don't register sessions for the guest user - its just too
  66            expensive to go through pam session code for browsing etc */
  67         if (vuser->guest) {
  68                 return True;
  69         }
  70
  71         if (!session_init())
  72                 return False;
  73
  74         ZERO_STRUCT(sessionid);
  75
  76         data.dptr = NULL;
  77         data.dsize = 0;
  78
  79         if (lp_utmp()) {
  80                 for (i=1;i<MAX_SESSION_ID;i++) {
  81                         slprintf(keystr, sizeof(keystr)-1, "ID/%d", i);
  82                         key.dptr = keystr;
  83                         key.dsize = strlen(keystr)+1;
  84
  85                         if (tdb_store(tdb, key, data, TDB_INSERT) == 0) break;
  86                 }
  87
  88                 if (i == MAX_SESSION_ID) {
  89                         DEBUG(1,("session_claim: out of session IDs (max is %d)\n",
  90                                  MAX_SESSION_ID));
  91                         return False;
  92                 }
  93                 slprintf(sessionid.id_str, sizeof(sessionid.id_str)-1, SESSION_UTMP_TEMPLATE, i);
  94                 tdb_store_flag = TDB_MODIFY;
  95         } else
  96         {
  97                 slprintf(keystr, sizeof(keystr)-1, "ID/%lu/%u",
  98                          (long unsigned int)sys_getpid(),
  99                          vuser->vuid);
 100                 slprintf(sessionid.id_str, sizeof(sessionid.id_str)-1,
 101                          SESSION_TEMPLATE, (long unsigned int)sys_getpid(),
 102                          vuser->vuid);
 103
 104                 key.dptr = keystr;
 105                 key.dsize = strlen(keystr)+1;
 106
 107                 tdb_store_flag = TDB_REPLACE;
 108         }
 109
 110         /* If 'hostname lookup' == yes, then do the DNS lookup.  This is
 111            needed because utmp and PAM both expect DNS names
 112
 113            client_name() handles this case internally.
 114         */
 115
 116         hostname = client_name();
 117         if (strcmp(hostname, "UNKNOWN") == 0) {
 118                 hostname = client_addr();
 119         }
 120
 121         fstrcpy(sessionid.username, vuser->user.unix_name);
 122         fstrcpy(sessionid.hostname, hostname);
 123         sessionid.id_num = i;  /* Only valid for utmp sessions */
 124         sessionid.pid = pid;
 125         sessionid.uid = vuser->uid;
 126         sessionid.gid = vuser->gid;
 127         fstrcpy(sessionid.remote_machine, get_remote_machine_name());
 128         fstrcpy(sessionid.ip_addr, client_addr());
 129
 130         client_ip = client_inaddr(&sa);
 131
 132         if (!smb_pam_claim_session(sessionid.username, sessionid.id_str, sessionid.hostname)) {
 133                 DEBUG(1,("pam_session rejected the session for %s [%s]\n",
 134                                 sessionid.username, sessionid.id_str));
 135                 if (tdb_store_flag == TDB_MODIFY) {
 136                         tdb_delete(tdb, key);
 137                 }
 138                 return False;
 139         }
 140
 141         data.dptr = (char *)&sessionid;
 142         data.dsize = sizeof(sessionid);
 143         if (tdb_store(tdb, key, data, tdb_store_flag) != 0) {
 144                 DEBUG(1,("session_claim: unable to create session id record\n"));
 145                 return False;
 146         }
 147
 148         if (lp_utmp()) {
 149                 sys_utmp_claim(sessionid.username, sessionid.hostname,
 150                                client_ip,
 151                                sessionid.id_str, sessionid.id_num);
 152         }
 153
 154         vuser->session_keystr = strdup(keystr);
 155         if (!vuser->session_keystr) {
 156                 DEBUG(0, ("session_claim:  strdup() failed for session_keystr\n"));
 157                 return False;
 158         }
 159         return True;
 160 }
 161
 162 /* called when a session is destroyed */
 163 void session_yield(user_struct *vuser)
 164 {
 165         TDB_DATA dbuf;
 166         struct sessionid sessionid;
 167         struct in_addr *client_ip;
 168         TDB_DATA key;
 169
 170         if (!tdb) return;
 171
 172         if (!vuser->session_keystr) {
 173                 return;
 174         }
 175
 176         key.dptr = vuser->session_keystr;
 177         key.dsize = strlen(vuser->session_keystr)+1;
 178
 179         dbuf = tdb_fetch(tdb, key);
 180
 181         if (dbuf.dsize != sizeof(sessionid))
 182                 return;
 183
 184         memcpy(&sessionid, dbuf.dptr, sizeof(sessionid));
 185
 186         client_ip = interpret_addr2(sessionid.ip_addr);
 187
 188         SAFE_FREE(dbuf.dptr);
 189
 190         if (lp_utmp()) {
 191                 sys_utmp_yield(sessionid.username, sessionid.hostname,
 192                                client_ip,
 193                                sessionid.id_str, sessionid.id_num);
 194         }
 195
 196         smb_pam_close_session(sessionid.username, sessionid.id_str, sessionid.hostname);
 197
 198         tdb_delete(tdb, key);
 199 }
 200
 201 static BOOL session_traverse(int (*fn)(TDB_CONTEXT *, TDB_DATA, TDB_DATA, void *), void *state)
 202 {
 203         if (!session_init()) {
 204                 DEBUG(3, ("No tdb opened\n"));
 205                 return False;
 206         }
 207
 208         tdb_traverse(tdb, fn, state);
 209         return True;
 210 }
 211
 212 struct session_list {
 213         int count;
 214         struct sessionid *sessions;
 215 };
 216
 217 static int gather_sessioninfo(TDB_CONTEXT *stdb, TDB_DATA kbuf, TDB_DATA dbuf,
 218                               void *state)
 219 {
 220         struct session_list *sesslist = (struct session_list *) state;
 221         const struct sessionid *current = (const struct sessionid *) dbuf.dptr;
 222
 223         sesslist->count += 1;
 224         sesslist->sessions = REALLOC(sesslist->sessions, sesslist->count *
 225                                       sizeof(struct sessionid));
 226
 227         memcpy(&sesslist->sessions[sesslist->count - 1], current,
 228                sizeof(struct sessionid));
 229         DEBUG(7,("gather_sessioninfo session from %s@%s\n",
 230                  current->username, current->remote_machine));
 231         return 0;
 232 }
 233
 234 int list_sessions(struct sessionid **session_list)
 235 {
 236         struct session_list sesslist;
 237
 238         sesslist.count = 0;
 239         sesslist.sessions = NULL;
 240
 241         if (!session_traverse(gather_sessioninfo, (void *) &sesslist)) {
 242                 DEBUG(3, ("Session traverse failed\n"));
 243                 SAFE_FREE(sesslist.sessions);
 244                 *session_list = NULL;
 245                 return 0;
 246         }
 247
 248         *session_list = sesslist.sessions;
 249         return sesslist.count;
 250 }