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