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