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