source3/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 3 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, see <http://www.gnu.org/licenses/>.
  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 #include "smbd/smbd.h"
  31 #include "smbd/globals.h"
  32 #include "dbwrap.h"
  33 #include "session.h"
  34 #include "auth.h"
  35
  36 /********************************************************************
  37  called when a session is created
  38 ********************************************************************/
  39
  40 bool session_claim(struct smbd_server_connection *sconn, user_struct *vuser)
  41 {
  42         struct server_id pid = sconn_server_id(sconn);
  43         TDB_DATA data;
  44         int i = 0;
  45         struct sessionid sessionid;
  46         fstring keystr;
  47         struct db_record *rec;
  48         NTSTATUS status;
  49
  50         vuser->session_keystr = NULL;
  51
  52         /* don't register sessions for the guest user - its just too
  53            expensive to go through pam session code for browsing etc */
  54         if (vuser->session_info->guest) {
  55                 return True;
  56         }
  57
  58         if (!sessionid_init()) {
  59                 return False;
  60         }
  61
  62         ZERO_STRUCT(sessionid);
  63
  64         data.dptr = NULL;
  65         data.dsize = 0;
  66
  67         if (lp_utmp()) {
  68
  69                 for (i=1;i<MAX_SESSION_ID;i++) {
  70
  71                         /*
  72                          * This is very inefficient and needs fixing -- vl
  73                          */
  74
  75                         struct server_id sess_pid;
  76
  77                         snprintf(keystr, sizeof(keystr), "ID/%d", i);
  78
  79                         rec = sessionid_fetch_record(NULL, keystr);
  80                         if (rec == NULL) {
  81                                 DEBUG(1, ("Could not lock \"%s\"\n", keystr));
  82                                 return False;
  83                         }
  84
  85                         if (rec->value.dsize != sizeof(sessionid)) {
  86                                 DEBUG(1, ("Re-using invalid record\n"));
  87                                 break;
  88                         }
  89
  90                         memcpy(&sess_pid,
  91                                ((char *)rec->value.dptr)
  92                                + offsetof(struct sessionid, pid),
  93                                sizeof(sess_pid));
  94
  95                         if (!process_exists(sess_pid)) {
  96                                 DEBUG(5, ("%s has died -- re-using session\n",
  97                                           procid_str_static(&sess_pid)));
  98                                 break;
  99                         }
 100
 101                         TALLOC_FREE(rec);
 102                 }
 103
 104                 if (i == MAX_SESSION_ID) {
 105                         SMB_ASSERT(rec == NULL);
 106                         DEBUG(1,("session_claim: out of session IDs "
 107                                  "(max is %d)\n", MAX_SESSION_ID));
 108                         return False;
 109                 }
 110
 111                 snprintf(sessionid.id_str, sizeof(sessionid.id_str),
 112                          SESSION_UTMP_TEMPLATE, i);
 113         } else
 114         {
 115                 snprintf(keystr, sizeof(keystr), "ID/%s/%u",
 116                          procid_str_static(&pid), vuser->vuid);
 117
 118                 rec = sessionid_fetch_record(NULL, keystr);
 119                 if (rec == NULL) {
 120                         DEBUG(1, ("Could not lock \"%s\"\n", keystr));
 121                         return False;
 122                 }
 123
 124                 snprintf(sessionid.id_str, sizeof(sessionid.id_str),
 125                          SESSION_TEMPLATE, (long unsigned int)sys_getpid(),
 126                          vuser->vuid);
 127         }
 128
 129         SMB_ASSERT(rec != NULL);
 130
 131         /* If 'hostname lookup' == yes, then do the DNS lookup.  This is
 132            needed because utmp and PAM both expect DNS names
 133
 134            client_name() handles this case internally.
 135         */
 136
 137         fstrcpy(sessionid.username, vuser->session_info->unix_name);
 138         fstrcpy(sessionid.hostname, sconn->client_id.name);
 139         sessionid.id_num = i;  /* Only valid for utmp sessions */
 140         sessionid.pid = pid;
 141         sessionid.uid = vuser->session_info->utok.uid;
 142         sessionid.gid = vuser->session_info->utok.gid;
 143         fstrcpy(sessionid.remote_machine, get_remote_machine_name());
 144         fstrcpy(sessionid.ip_addr_str, sconn->client_id.addr);
 145         sessionid.connect_start = time(NULL);
 146
 147         if (!smb_pam_claim_session(sessionid.username, sessionid.id_str,
 148                                    sessionid.hostname)) {
 149                 DEBUG(1,("pam_session rejected the session for %s [%s]\n",
 150                                 sessionid.username, sessionid.id_str));
 151
 152                 TALLOC_FREE(rec);
 153                 return False;
 154         }
 155
 156         data.dptr = (uint8 *)&sessionid;
 157         data.dsize = sizeof(sessionid);
 158
 159         status = rec->store(rec, data, TDB_REPLACE);
 160
 161         TALLOC_FREE(rec);
 162
 163         if (!NT_STATUS_IS_OK(status)) {
 164                 DEBUG(1,("session_claim: unable to create session id "
 165                          "record: %s\n", nt_errstr(status)));
 166                 return False;
 167         }
 168
 169         if (lp_utmp()) {
 170                 sys_utmp_claim(sessionid.username, sessionid.hostname,
 171                                sessionid.ip_addr_str,
 172                                sessionid.id_str, sessionid.id_num);
 173         }
 174
 175         vuser->session_keystr = talloc_strdup(vuser, keystr);
 176         if (!vuser->session_keystr) {
 177                 DEBUG(0, ("session_claim:  talloc_strdup() failed for session_keystr\n"));
 178                 return False;
 179         }
 180         return True;
 181 }
 182
 183 /********************************************************************
 184  called when a session is destroyed
 185 ********************************************************************/
 186
 187 void session_yield(user_struct *vuser)
 188 {
 189         struct sessionid sessionid;
 190         struct db_record *rec;
 191
 192         if (!vuser->session_keystr) {
 193                 return;
 194         }
 195
 196         rec = sessionid_fetch_record(NULL, vuser->session_keystr);
 197         if (rec == NULL) {
 198                 return;
 199         }
 200
 201         if (rec->value.dsize != sizeof(sessionid))
 202                 return;
 203
 204         memcpy(&sessionid, rec->value.dptr, sizeof(sessionid));
 205
 206         if (lp_utmp()) {
 207                 sys_utmp_yield(sessionid.username, sessionid.hostname,
 208                                sessionid.ip_addr_str,
 209                                sessionid.id_str, sessionid.id_num);
 210         }
 211
 212         smb_pam_close_session(sessionid.username, sessionid.id_str,
 213                               sessionid.hostname);
 214
 215         rec->delete_rec(rec);
 216
 217         TALLOC_FREE(rec);
 218 }
 219
 220 /********************************************************************
 221 ********************************************************************/
 222
 223 struct session_list {
 224         TALLOC_CTX *mem_ctx;
 225         int count;
 226         struct sessionid *sessions;
 227 };
 228
 229 static int gather_sessioninfo(const char *key, struct sessionid *session,
 230                               void *private_data)
 231 {
 232         struct session_list *sesslist = (struct session_list *)private_data;
 233
 234         sesslist->sessions = TALLOC_REALLOC_ARRAY(
 235                 sesslist->mem_ctx, sesslist->sessions, struct sessionid,
 236                 sesslist->count+1);
 237
 238         if (!sesslist->sessions) {
 239                 sesslist->count = 0;
 240                 return -1;
 241         }
 242
 243         memcpy(&sesslist->sessions[sesslist->count], session,
 244                sizeof(struct sessionid));
 245
 246         sesslist->count++;
 247
 248         DEBUG(7, ("gather_sessioninfo session from %s@%s\n",
 249                   session->username, session->remote_machine));
 250
 251         return 0;
 252 }
 253
 254 /********************************************************************
 255 ********************************************************************/
 256
 257 int list_sessions(TALLOC_CTX *mem_ctx, struct sessionid **session_list)
 258 {
 259         struct session_list sesslist;
 260         int ret;
 261
 262         sesslist.mem_ctx = mem_ctx;
 263         sesslist.count = 0;
 264         sesslist.sessions = NULL;
 265
 266         ret = sessionid_traverse_read(gather_sessioninfo, (void *) &sesslist);
 267         if (ret == -1) {
 268                 DEBUG(3, ("Session traverse failed\n"));
 269                 SAFE_FREE(sesslist.sessions);
 270                 *session_list = NULL;
 271                 return 0;
 272         }
 273
 274         *session_list = sesslist.sessions;
 275         return sesslist.count;
 276 }