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