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