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/dbwrap.h"
  33 #include "session.h"
  34 #include "auth.h"
  35 #include "../lib/tsocket/tsocket.h"
  36 #include "../libcli/security/security.h"
  37
  38 /********************************************************************
  39  called when a session is created
  40 ********************************************************************/
  41
  42 bool session_claim(struct smbd_server_connection *sconn, user_struct *vuser)
  43 {
  44         struct server_id pid = sconn_server_id(sconn);
  45         TDB_DATA data;
  46         int i = 0;
  47         struct sessionid sessionid;
  48         fstring keystr;
  49         struct db_record *rec;
  50         NTSTATUS status;
  51         char *raddr;
  52
  53         vuser->session_keystr = NULL;
  54
  55         /* don't register sessions for the guest user - its just too
  56            expensive to go through pam session code for browsing etc */
  57         if (security_session_user_level(vuser->session_info, NULL) < SECURITY_USER) {
  58                 return True;
  59         }
  60
  61         if (!sessionid_init()) {
  62                 return False;
  63         }
  64
  65         ZERO_STRUCT(sessionid);
  66
  67         data.dptr = NULL;
  68         data.dsize = 0;
  69
  70         if (lp_utmp()) {
  71
  72                 for (i=1;i<MAX_SESSION_ID;i++) {
  73
  74                         /*
  75                          * This is very inefficient and needs fixing -- vl
  76                          */
  77
  78                         struct server_id sess_pid;
  79
  80                         snprintf(keystr, sizeof(keystr), "ID/%d", i);
  81
  82                         rec = sessionid_fetch_record(NULL, keystr);
  83                         if (rec == NULL) {
  84                                 DEBUG(1, ("Could not lock \"%s\"\n", keystr));
  85                                 return False;
  86                         }
  87
  88                         if (rec->value.dsize != sizeof(sessionid)) {
  89                                 DEBUG(1, ("Re-using invalid record\n"));
  90                                 break;
  91                         }
  92
  93                         memcpy(&sess_pid,
  94                                ((char *)rec->value.dptr)
  95                                + offsetof(struct sessionid, pid),
  96                                sizeof(sess_pid));
  97
  98                         if (!process_exists(sess_pid)) {
  99                                 DEBUG(5, ("%s has died -- re-using session\n",
 100                                           procid_str_static(&sess_pid)));
 101                                 break;
 102                         }
 103
 104                         TALLOC_FREE(rec);
 105                 }
 106
 107                 if (i == MAX_SESSION_ID) {
 108                         SMB_ASSERT(rec == NULL);
 109                         DEBUG(1,("session_claim: out of session IDs "
 110                                  "(max is %d)\n", MAX_SESSION_ID));
 111                         return False;
 112                 }
 113
 114                 snprintf(sessionid.id_str, sizeof(sessionid.id_str),
 115                          SESSION_UTMP_TEMPLATE, i);
 116         } else
 117         {
 118                 snprintf(keystr, sizeof(keystr), "ID/%s/%u",
 119                          procid_str_static(&pid), vuser->vuid);
 120
 121                 rec = sessionid_fetch_record(NULL, keystr);
 122                 if (rec == NULL) {
 123                         DEBUG(1, ("Could not lock \"%s\"\n", keystr));
 124                         return False;
 125                 }
 126
 127                 snprintf(sessionid.id_str, sizeof(sessionid.id_str),
 128                          SESSION_TEMPLATE, (long unsigned int)sys_getpid(),
 129                          vuser->vuid);
 130         }
 131
 132         SMB_ASSERT(rec != NULL);
 133
 134         raddr = tsocket_address_inet_addr_string(sconn->remote_address,
 135                                                  talloc_tos());
 136         if (raddr == NULL) {
 137                 return false;
 138         }
 139
 140         /* Make clear that we require the optional unix_token in the source3 code */
 141         SMB_ASSERT(vuser->session_info->unix_token);
 142
 143         fstrcpy(sessionid.username, vuser->session_info->unix_info->unix_name);
 144         fstrcpy(sessionid.hostname, sconn->remote_hostname);
 145         sessionid.id_num = i;  /* Only valid for utmp sessions */
 146         sessionid.pid = pid;
 147         sessionid.uid = vuser->session_info->unix_token->uid;
 148         sessionid.gid = vuser->session_info->unix_token->gid;
 149         fstrcpy(sessionid.remote_machine, get_remote_machine_name());
 150         fstrcpy(sessionid.ip_addr_str, raddr);
 151         sessionid.connect_start = time(NULL);
 152
 153         if (!smb_pam_claim_session(sessionid.username, sessionid.id_str,
 154                                    sessionid.hostname)) {
 155                 DEBUG(1,("pam_session rejected the session for %s [%s]\n",
 156                                 sessionid.username, sessionid.id_str));
 157
 158                 TALLOC_FREE(rec);
 159                 return False;
 160         }
 161
 162         data.dptr = (uint8 *)&sessionid;
 163         data.dsize = sizeof(sessionid);
 164
 165         status = rec->store(rec, data, TDB_REPLACE);
 166
 167         TALLOC_FREE(rec);
 168
 169         if (!NT_STATUS_IS_OK(status)) {
 170                 DEBUG(1,("session_claim: unable to create session id "
 171                          "record: %s\n", nt_errstr(status)));
 172                 return False;
 173         }
 174
 175         if (lp_utmp()) {
 176                 sys_utmp_claim(sessionid.username, sessionid.hostname,
 177                                sessionid.ip_addr_str,
 178                                sessionid.id_str, sessionid.id_num);
 179         }
 180
 181         vuser->session_keystr = talloc_strdup(vuser, keystr);
 182         if (!vuser->session_keystr) {
 183                 DEBUG(0, ("session_claim:  talloc_strdup() failed for session_keystr\n"));
 184                 return False;
 185         }
 186         return True;
 187 }
 188
 189 /********************************************************************
 190  called when a session is destroyed
 191 ********************************************************************/
 192
 193 void session_yield(user_struct *vuser)
 194 {
 195         struct sessionid sessionid;
 196         struct db_record *rec;
 197
 198         if (!vuser->session_keystr) {
 199                 return;
 200         }
 201
 202         rec = sessionid_fetch_record(NULL, vuser->session_keystr);
 203         if (rec == NULL) {
 204                 return;
 205         }
 206
 207         if (rec->value.dsize != sizeof(sessionid))
 208                 return;
 209
 210         memcpy(&sessionid, rec->value.dptr, sizeof(sessionid));
 211
 212         if (lp_utmp()) {
 213                 sys_utmp_yield(sessionid.username, sessionid.hostname,
 214                                sessionid.ip_addr_str,
 215                                sessionid.id_str, sessionid.id_num);
 216         }
 217
 218         smb_pam_close_session(sessionid.username, sessionid.id_str,
 219                               sessionid.hostname);
 220
 221         rec->delete_rec(rec);
 222
 223         TALLOC_FREE(rec);
 224 }
 225
 226 /********************************************************************
 227 ********************************************************************/
 228
 229 struct session_list {
 230         TALLOC_CTX *mem_ctx;
 231         int count;
 232         struct sessionid *sessions;
 233 };
 234
 235 static int gather_sessioninfo(const char *key, struct sessionid *session,
 236                               void *private_data)
 237 {
 238         struct session_list *sesslist = (struct session_list *)private_data;
 239
 240         sesslist->sessions = talloc_realloc(
 241                 sesslist->mem_ctx, sesslist->sessions, struct sessionid,
 242                 sesslist->count+1);
 243
 244         if (!sesslist->sessions) {
 245                 sesslist->count = 0;
 246                 return -1;
 247         }
 248
 249         memcpy(&sesslist->sessions[sesslist->count], session,
 250                sizeof(struct sessionid));
 251
 252         sesslist->count++;
 253
 254         DEBUG(7, ("gather_sessioninfo session from %s@%s\n",
 255                   session->username, session->remote_machine));
 256
 257         return 0;
 258 }
 259
 260 /********************************************************************
 261 ********************************************************************/
 262
 263 int list_sessions(TALLOC_CTX *mem_ctx, struct sessionid **session_list)
 264 {
 265         struct session_list sesslist;
 266         int ret;
 267
 268         sesslist.mem_ctx = mem_ctx;
 269         sesslist.count = 0;
 270         sesslist.sessions = NULL;
 271
 272         ret = sessionid_traverse_read(gather_sessioninfo, (void *) &sesslist);
 273         if (ret < 0) {
 274                 DEBUG(3, ("Session traverse failed\n"));
 275                 SAFE_FREE(sesslist.sessions);
 276                 *session_list = NULL;
 277                 return 0;
 278         }
 279
 280         *session_list = sesslist.sessions;
 281         return sesslist.count;
 282 }