source/smbd/session.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 2.0
   4    session handling for utmp and PAM
   5    Copyright (C) tridge@samba.org 2001
   6    Copyright (C) abartlet@pcug.org.au 2001
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  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
  31 #if defined(WITH_PAM) || defined(WITH_UTMP)
  32
  33 static TDB_CONTEXT *tdb;
  34 struct sessionid {
  35         fstring username;
  36         fstring hostname;
  37         fstring id_str;
  38         uint32  id_num;
  39         uint32  pid;
  40 };
  41
  42 /* called when a session is created */
  43 BOOL session_claim(uint16 vuid)
  44 {
  45         user_struct *vuser = get_valid_user_struct(vuid);
  46         int i;
  47         TDB_DATA data;
  48         struct sessionid sessionid;
  49         pstring dbuf;
  50         int dlen;
  51         uint32 pid = (uint32)sys_getpid();
  52         TDB_DATA key;
  53         fstring keystr;
  54
  55         vuser->session_id = 0;
  56
  57         /* don't register sessions for the guest user - its just too
  58            expensive to go through pam session code for browsing etc */
  59         if (strequal(vuser->user.unix_name,lp_guestaccount(-1))) {
  60                 return True;
  61         }
  62
  63         if (!tdb) {
  64                 tdb = tdb_open(lock_path("sessionid.tdb"), 0, TDB_CLEAR_IF_FIRST,
  65                                O_RDWR | O_CREAT, 0644);
  66                 if (!tdb) {
  67                         DEBUG(1,("session_claim: failed to open sessionid tdb\n"));
  68                         return False;
  69                 }
  70         }
  71
  72         ZERO_STRUCT(sessionid);
  73
  74         data.dptr = NULL;
  75         data.dsize = 0;
  76
  77         for (i=1;i<MAX_SESSION_ID;i++) {
  78                 slprintf(keystr, sizeof(keystr)-1, "ID/%d", i);
  79                 key.dptr = keystr;
  80                 key.dsize = strlen(keystr)+1;
  81
  82                 if (tdb_store(tdb, key, data, TDB_INSERT) == 0) break;
  83         }
  84
  85         if (i == MAX_SESSION_ID) {
  86                 DEBUG(1,("session_claim: out of session IDs (max is %d)\n",
  87                          MAX_SESSION_ID));
  88                 return False;
  89         }
  90
  91         fstrcpy(sessionid.username, vuser->user.unix_name);
  92 #if WITH_UTMP
  93         fstrcpy(sessionid.hostname, lp_utmp_hostname());
  94 #else
  95         {
  96                 extern fstring remote_machine;
  97                 fstrcpy(sessionid.hostname, remote_machine);
  98         }
  99 #endif
 100         slprintf(sessionid.id_str, sizeof(sessionid.id_str)-1, SESSION_TEMPLATE, i);
 101         sessionid.id_num = i;
 102         sessionid.pid = pid;
 103
 104         dlen = tdb_pack(dbuf, sizeof(dbuf), "fffdd",
 105                         sessionid.username, sessionid.hostname, sessionid.id_str,
 106                         sessionid.id_num, sessionid.pid);
 107
 108         data.dptr = dbuf;
 109         data.dsize = dlen;
 110         if (tdb_store(tdb, key, data, TDB_MODIFY) != 0) {
 111                 DEBUG(1,("session_claim: unable to create session id record\n"));
 112                 return False;
 113         }
 114
 115 #if WITH_PAM
 116         if (!pam_session(True, sessionid.username, sessionid.id_str)) {
 117                 DEBUG(1,("pam_session rejected the session for %s [%s]\n",
 118                          sessionid.username, sessionid.id_str));
 119                 tdb_delete(tdb, key);
 120                 return False;
 121         }
 122 #endif
 123
 124 #if WITH_UTMP
 125         if (lp_utmp()) {
 126                 sys_utmp_claim(sessionid.username, sessionid.hostname,
 127                                sessionid.id_str, sessionid.id_num);
 128         }
 129 #endif
 130
 131         vuser->session_id = i;
 132         return True;
 133 }
 134
 135 /* called when a session is destroyed */
 136 void session_yield(uint16 vuid)
 137 {
 138         user_struct *vuser = get_valid_user_struct(vuid);
 139         TDB_DATA data;
 140         struct sessionid sessionid;
 141         TDB_DATA key;
 142         fstring keystr;
 143
 144         if (!tdb) return;
 145
 146         if (vuser->session_id == 0) {
 147                 return;
 148         }
 149
 150         slprintf(keystr, sizeof(keystr)-1, "ID/%d", vuser->session_id);
 151
 152         key.dptr = keystr;
 153         key.dsize = strlen(keystr)+1;
 154
 155         data = tdb_fetch(tdb, key);
 156         if (data.dptr == NULL) {
 157                 return;
 158         }
 159
 160         tdb_unpack(data.dptr, data.dsize, "fffdd",
 161                    &sessionid.username, &sessionid.hostname, &sessionid.id_str,
 162                    &sessionid.id_num, &sessionid.pid);
 163
 164 #if WITH_UTMP
 165         if (lp_utmp()) {
 166                 sys_utmp_yield(sessionid.username, sessionid.hostname,
 167                                sessionid.id_str, sessionid.id_num);
 168         }
 169 #endif
 170
 171 #if WITH_PAM
 172         pam_session(False, sessionid.username, sessionid.id_str);
 173 #endif
 174
 175         tdb_delete(tdb, key);
 176 }
 177
 178 #else
 179  /* null functions - no session support needed */
 180  BOOL session_claim(uint16 vuid) { return True; }
 181  void session_yield(uint16 vuid) {}
 182 #endif