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         char * hostname;
  55
  56         vuser->session_id = 0;
  57
  58         /* don't register sessions for the guest user - its just too
  59            expensive to go through pam session code for browsing etc */
  60         if (strequal(vuser->user.unix_name,lp_guestaccount(-1))) {
  61                 return True;
  62         }
  63
  64         if (!tdb) {
  65                 tdb = tdb_open(lock_path("sessionid.tdb"), 0, TDB_CLEAR_IF_FIRST,
  66                                O_RDWR | O_CREAT, 0644);
  67                 if (!tdb) {
  68                         DEBUG(1,("session_claim: failed to open sessionid tdb\n"));
  69                         return False;
  70                 }
  71         }
  72
  73         ZERO_STRUCT(sessionid);
  74
  75         data.dptr = NULL;
  76         data.dsize = 0;
  77
  78         for (i=1;i<MAX_SESSION_ID;i++) {
  79                 slprintf(keystr, sizeof(keystr)-1, "ID/%d", i);
  80                 key.dptr = keystr;
  81                 key.dsize = strlen(keystr)+1;
  82
  83                 if (tdb_store(tdb, key, data, TDB_INSERT) == 0) break;
  84         }
  85
  86         if (i == MAX_SESSION_ID) {
  87                 DEBUG(1,("session_claim: out of session IDs (max is %d)\n",
  88                          MAX_SESSION_ID));
  89                 return False;
  90         }
  91
  92         hostname = client_name();
  93         if (strequal(hostname,"UNKNOWN"))
  94                 hostname = client_addr();
  95
  96         fstrcpy(sessionid.username, vuser->user.unix_name);
  97         fstrcpy(sessionid.hostname, hostname);
  98         slprintf(sessionid.id_str, sizeof(sessionid.id_str)-1, SESSION_TEMPLATE, i);
  99         sessionid.id_num = i;
 100         sessionid.pid = pid;
 101
 102         dlen = tdb_pack(dbuf, sizeof(dbuf), "fffdd",
 103                         sessionid.username, sessionid.hostname, sessionid.id_str,
 104                         sessionid.id_num, sessionid.pid);
 105
 106         data.dptr = dbuf;
 107         data.dsize = dlen;
 108         if (tdb_store(tdb, key, data, TDB_MODIFY) != 0) {
 109                 DEBUG(1,("session_claim: unable to create session id record\n"));
 110                 return False;
 111         }
 112
 113 #if WITH_PAM
 114         if (!smb_pam_session(True, sessionid.username, sessionid.id_str, sessionid.hostname)) {
 115                 DEBUG(1,("smb_pam_session rejected the session for %s [%s]\n",
 116                          sessionid.username, sessionid.id_str));
 117                 tdb_delete(tdb, key);
 118                 return False;
 119         }
 120 #endif
 121
 122 #if WITH_UTMP
 123         if (lp_utmp()) {
 124                 sys_utmp_claim(sessionid.username, sessionid.hostname,
 125                                sessionid.id_str, sessionid.id_num);
 126         }
 127 #endif
 128
 129         vuser->session_id = i;
 130         return True;
 131 }
 132
 133 /* called when a session is destroyed */
 134 void session_yield(uint16 vuid)
 135 {
 136         user_struct *vuser = get_valid_user_struct(vuid);
 137         TDB_DATA data;
 138         struct sessionid sessionid;
 139         TDB_DATA key;
 140         fstring keystr;
 141
 142         if (!tdb) return;
 143
 144         if (vuser->session_id == 0) {
 145                 return;
 146         }
 147
 148         slprintf(keystr, sizeof(keystr)-1, "ID/%d", vuser->session_id);
 149
 150         key.dptr = keystr;
 151         key.dsize = strlen(keystr)+1;
 152
 153         data = tdb_fetch(tdb, key);
 154         if (data.dptr == NULL) {
 155                 return;
 156         }
 157
 158         tdb_unpack(data.dptr, data.dsize, "fffdd",
 159                    &sessionid.username, &sessionid.hostname, &sessionid.id_str,
 160                    &sessionid.id_num, &sessionid.pid);
 161
 162         safe_free(data.dptr);
 163         data.dptr = NULL;
 164
 165 #if WITH_UTMP
 166         if (lp_utmp()) {
 167                 sys_utmp_yield(sessionid.username, sessionid.hostname,
 168                                sessionid.id_str, sessionid.id_num);
 169         }
 170 #endif
 171
 172 #if WITH_PAM
 173         smb_pam_session(False, sessionid.username, sessionid.id_str, sessionid.hostname);
 174 #endif
 175
 176         tdb_delete(tdb, key);
 177 }
 178
 179 #else
 180  /* null functions - no session support needed */
 181  BOOL session_claim(uint16 vuid) { return True; }
 182  void session_yield(uint16 vuid) {}
 183 #endif