source/smbd/session.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    session handling for utmp and PAM
   4
   5    Copyright (C) tridge@samba.org       2001
   6    Copyright (C) abartlet@samba.org     2001
   7    Copyright (C) Gerald (Jerry) Carter  2006
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 2 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program; if not, write to the Free Software
  21    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22 */
  23
  24 /* a "session" is claimed when we do a SessionSetupX operation
  25    and is yielded when the corresponding vuid is destroyed.
  26
  27    sessions are used to populate utmp and PAM session structures
  28 */
  29
  30 #include "includes.h"
  31
  32 static TDB_CONTEXT *tdb;
  33
  34 /********************************************************************
  35 ********************************************************************/
  36
  37 BOOL session_init(void)
  38 {
  39         if (tdb)
  40                 return True;
  41
  42         tdb = tdb_open_log(lock_path("sessionid.tdb"), 0, TDB_CLEAR_IF_FIRST|TDB_DEFAULT,
  43                        O_RDWR | O_CREAT, 0644);
  44         if (!tdb) {
  45                 DEBUG(1,("session_init: failed to open sessionid tdb\n"));
  46                 return False;
  47         }
  48
  49         return True;
  50 }
  51
  52 /********************************************************************
  53  called when a session is created
  54 ********************************************************************/
  55
  56 BOOL session_claim(user_struct *vuser)
  57 {
  58         int i = 0;
  59         TDB_DATA data;
  60         struct sockaddr sa;
  61         struct in_addr *client_ip;
  62         struct sessionid sessionid;
  63         uint32 pid = (uint32)sys_getpid();
  64         TDB_DATA key;
  65         fstring keystr;
  66         char * hostname;
  67         int tdb_store_flag;  /* If using utmp, we do an inital 'lock hold' store,
  68                                 but we don't need this if we are just using the
  69                                 (unique) pid/vuid combination */
  70
  71         vuser->session_keystr = NULL;
  72
  73         /* don't register sessions for the guest user - its just too
  74            expensive to go through pam session code for browsing etc */
  75         if (vuser->guest) {
  76                 return True;
  77         }
  78
  79         if (!session_init())
  80                 return False;
  81
  82         ZERO_STRUCT(sessionid);
  83
  84         data.dptr = NULL;
  85         data.dsize = 0;
  86
  87         if (lp_utmp()) {
  88                 for (i=1;i<MAX_SESSION_ID;i++) {
  89                         slprintf(keystr, sizeof(keystr)-1, "ID/%d", i);
  90                         key.dptr = keystr;
  91                         key.dsize = strlen(keystr)+1;
  92
  93                         if (tdb_store(tdb, key, data, TDB_INSERT) == 0) break;
  94                 }
  95
  96                 if (i == MAX_SESSION_ID) {
  97                         DEBUG(1,("session_claim: out of session IDs (max is %d)\n",
  98                                  MAX_SESSION_ID));
  99                         return False;
 100                 }
 101                 slprintf(sessionid.id_str, sizeof(sessionid.id_str)-1, SESSION_UTMP_TEMPLATE, i);
 102                 tdb_store_flag = TDB_MODIFY;
 103         } else
 104         {
 105                 slprintf(keystr, sizeof(keystr)-1, "ID/%lu/%u",
 106                          (long unsigned int)sys_getpid(),
 107                          vuser->vuid);
 108                 slprintf(sessionid.id_str, sizeof(sessionid.id_str)-1,
 109                          SESSION_TEMPLATE, (long unsigned int)sys_getpid(),
 110                          vuser->vuid);
 111
 112                 key.dptr = keystr;
 113                 key.dsize = strlen(keystr)+1;
 114
 115                 tdb_store_flag = TDB_REPLACE;
 116         }
 117
 118         /* If 'hostname lookup' == yes, then do the DNS lookup.  This is
 119            needed because utmp and PAM both expect DNS names
 120
 121            client_name() handles this case internally.
 122         */
 123
 124         hostname = client_name();
 125         if (strcmp(hostname, "UNKNOWN") == 0) {
 126                 hostname = client_addr();
 127         }
 128
 129         fstrcpy(sessionid.username, vuser->user.unix_name);
 130         fstrcpy(sessionid.hostname, hostname);
 131         sessionid.id_num = i;  /* Only valid for utmp sessions */
 132         sessionid.pid = pid;
 133         sessionid.uid = vuser->uid;
 134         sessionid.gid = vuser->gid;
 135         fstrcpy(sessionid.remote_machine, get_remote_machine_name());
 136         fstrcpy(sessionid.ip_addr, client_addr());
 137         sessionid.connect_start = time(NULL);
 138
 139         client_ip = client_inaddr(&sa);
 140
 141         if (!smb_pam_claim_session(sessionid.username, sessionid.id_str, sessionid.hostname)) {
 142                 DEBUG(1,("pam_session rejected the session for %s [%s]\n",
 143                                 sessionid.username, sessionid.id_str));
 144                 if (tdb_store_flag == TDB_MODIFY) {
 145                         tdb_delete(tdb, key);
 146                 }
 147                 return False;
 148         }
 149
 150         data.dptr = (char *)&sessionid;
 151         data.dsize = sizeof(sessionid);
 152         if (tdb_store(tdb, key, data, tdb_store_flag) != 0) {
 153                 DEBUG(1,("session_claim: unable to create session id record\n"));
 154                 return False;
 155         }
 156
 157         if (lp_utmp()) {
 158                 sys_utmp_claim(sessionid.username, sessionid.hostname,
 159                                client_ip,
 160                                sessionid.id_str, sessionid.id_num);
 161         }
 162
 163         vuser->session_keystr = SMB_STRDUP(keystr);
 164         if (!vuser->session_keystr) {
 165                 DEBUG(0, ("session_claim:  strdup() failed for session_keystr\n"));
 166                 return False;
 167         }
 168         return True;
 169 }
 170
 171 /********************************************************************
 172  called when a session is destroyed
 173 ********************************************************************/
 174
 175 void session_yield(user_struct *vuser)
 176 {
 177         TDB_DATA dbuf;
 178         struct sessionid sessionid;
 179         struct in_addr *client_ip;
 180         TDB_DATA key;
 181
 182         if (!tdb) return;
 183
 184         if (!vuser->session_keystr) {
 185                 return;
 186         }
 187
 188         key.dptr = vuser->session_keystr;
 189         key.dsize = strlen(vuser->session_keystr)+1;
 190
 191         dbuf = tdb_fetch(tdb, key);
 192
 193         if (dbuf.dsize != sizeof(sessionid))
 194                 return;
 195
 196         memcpy(&sessionid, dbuf.dptr, sizeof(sessionid));
 197
 198         client_ip = interpret_addr2(sessionid.ip_addr);
 199
 200         SAFE_FREE(dbuf.dptr);
 201
 202         if (lp_utmp()) {
 203                 sys_utmp_yield(sessionid.username, sessionid.hostname,
 204                                client_ip,
 205                                sessionid.id_str, sessionid.id_num);
 206         }
 207
 208         smb_pam_close_session(sessionid.username, sessionid.id_str, sessionid.hostname);
 209
 210         tdb_delete(tdb, key);
 211 }
 212
 213 /********************************************************************
 214 ********************************************************************/
 215
 216 BOOL session_traverse(int (*fn)(TDB_CONTEXT *, TDB_DATA, TDB_DATA, void *),
 217                       void *state)
 218 {
 219         if (!session_init()) {
 220                 DEBUG(3, ("No tdb opened\n"));
 221                 return False;
 222         }
 223
 224         tdb_traverse(tdb, fn, state);
 225         return True;
 226 }
 227
 228 /********************************************************************
 229 ********************************************************************/
 230
 231 struct session_list {
 232         int count;
 233         struct sessionid *sessions;
 234 };
 235
 236 static int gather_sessioninfo(TDB_CONTEXT *stdb, TDB_DATA kbuf, TDB_DATA dbuf, void *state)
 237 {
 238         uint32 i;
 239         struct session_list *sesslist = (struct session_list *) state;
 240         const struct sessionid *current = (const struct sessionid *) dbuf.dptr;
 241
 242         i = sesslist->count;
 243
 244         sesslist->sessions = SMB_REALLOC_ARRAY(sesslist->sessions, struct sessionid, i+1);
 245         if (!sesslist->sessions) {
 246                 sesslist->count = 0;
 247                 return -1;
 248         }
 249
 250         memcpy(&sesslist->sessions[i], current, sizeof(struct sessionid));
 251         sesslist->count++;
 252
 253         DEBUG(7,("gather_sessioninfo session from %s@%s\n",
 254                  current->username, current->remote_machine));
 255
 256         return 0;
 257 }
 258
 259 /********************************************************************
 260 ********************************************************************/
 261
 262 int list_sessions(struct sessionid **session_list)
 263 {
 264         struct session_list sesslist;
 265
 266         sesslist.count = 0;
 267         sesslist.sessions = NULL;
 268
 269         if (!session_traverse(gather_sessioninfo, (void *) &sesslist)) {
 270                 DEBUG(3, ("Session traverse failed\n"));
 271                 SAFE_FREE(sesslist.sessions);
 272                 *session_list = NULL;
 273                 return 0;
 274         }
 275
 276         *session_list = sesslist.sessions;
 277         return sesslist.count;
 278 }