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 #include "messages.h"
  38
  39 /********************************************************************
  40  called when a session is created
  41 ********************************************************************/
  42
  43 bool session_claim(struct smbd_server_connection *sconn, struct user_struct *vuser)
  44 {
  45         struct server_id pid = messaging_server_id(sconn->msg_ctx);
  46         TDB_DATA data;
  47         int i = 0;
  48         struct sessionid sessionid;
  49         fstring keystr;
  50         struct db_record *rec;
  51         NTSTATUS status;
  52         char *raddr;
  53
  54         vuser->session_keystr = NULL;
  55
  56         /* don't register sessions for the guest user - its just too
  57            expensive to go through pam session code for browsing etc */
  58         if (security_session_user_level(vuser->session_info, NULL) < SECURITY_USER) {
  59                 return True;
  60         }
  61
  62         if (!sessionid_init()) {
  63                 return False;
  64         }
  65
  66         ZERO_STRUCT(sessionid);
  67
  68         data.dptr = NULL;
  69         data.dsize = 0;
  70
  71         if (lp_utmp()) {
  72
  73                 for (i=1;i<MAX_SESSION_ID;i++) {
  74
  75                         /*
  76                          * This is very inefficient and needs fixing -- vl
  77                          */
  78
  79                         struct server_id sess_pid;
  80                         TDB_DATA value;
  81
  82                         snprintf(keystr, sizeof(keystr), "ID/%d", i);
  83
  84                         rec = sessionid_fetch_record(NULL, keystr);
  85                         if (rec == NULL) {
  86                                 DEBUG(1, ("Could not lock \"%s\"\n", keystr));
  87                                 return False;
  88                         }
  89
  90                         value = dbwrap_record_get_value(rec);
  91
  92                         if (value.dsize != sizeof(sessionid)) {
  93                                 DEBUG(1, ("Re-using invalid record\n"));
  94                                 break;
  95                         }
  96
  97                         memcpy(&sess_pid,
  98                                ((char *)value.dptr)
  99                                + offsetof(struct sessionid, pid),
 100                                sizeof(sess_pid));
 101
 102                         if (!process_exists(sess_pid)) {
 103                                 DEBUG(5, ("%s has died -- re-using session\n",
 104                                           procid_str_static(&sess_pid)));
 105                                 break;
 106                         }
 107
 108                         TALLOC_FREE(rec);
 109                 }
 110
 111                 if (i == MAX_SESSION_ID) {
 112                         SMB_ASSERT(rec == NULL);
 113                         DEBUG(1,("session_claim: out of session IDs "
 114                                  "(max is %d)\n", MAX_SESSION_ID));
 115                         return False;
 116                 }
 117
 118                 snprintf(sessionid.id_str, sizeof(sessionid.id_str),
 119                          SESSION_UTMP_TEMPLATE, i);
 120         } else
 121         {
 122                 snprintf(keystr, sizeof(keystr), "ID/%s/%llu",
 123                          procid_str_static(&pid),
 124                          (unsigned long long)vuser->vuid);
 125
 126                 rec = sessionid_fetch_record(NULL, keystr);
 127                 if (rec == NULL) {
 128                         DEBUG(1, ("Could not lock \"%s\"\n", keystr));
 129                         return False;
 130                 }
 131
 132                 snprintf(sessionid.id_str, sizeof(sessionid.id_str),
 133                          SESSION_TEMPLATE, (long unsigned int)getpid(),
 134                          (unsigned long long)vuser->vuid);
 135         }
 136
 137         SMB_ASSERT(rec != NULL);
 138
 139         raddr = tsocket_address_inet_addr_string(sconn->remote_address,
 140                                                  talloc_tos());
 141         if (raddr == NULL) {
 142                 return false;
 143         }
 144
 145         /* Make clear that we require the optional unix_token in the source3 code */
 146         SMB_ASSERT(vuser->session_info->unix_token);
 147
 148         fstrcpy(sessionid.username, vuser->session_info->unix_info->unix_name);
 149         fstrcpy(sessionid.hostname, sconn->remote_hostname);
 150         sessionid.id_num = i;  /* Only valid for utmp sessions */
 151         sessionid.pid = pid;
 152         sessionid.uid = vuser->session_info->unix_token->uid;
 153         sessionid.gid = vuser->session_info->unix_token->gid;
 154         fstrcpy(sessionid.remote_machine, get_remote_machine_name());
 155         fstrcpy(sessionid.ip_addr_str, raddr);
 156         sessionid.connect_start = time(NULL);
 157
 158         if (!smb_pam_claim_session(sessionid.username, sessionid.id_str,
 159                                    sessionid.hostname)) {
 160                 DEBUG(1,("pam_session rejected the session for %s [%s]\n",
 161                                 sessionid.username, sessionid.id_str));
 162
 163                 TALLOC_FREE(rec);
 164                 return False;
 165         }
 166
 167         data.dptr = (uint8 *)&sessionid;
 168         data.dsize = sizeof(sessionid);
 169
 170         status = dbwrap_record_store(rec, data, TDB_REPLACE);
 171
 172         TALLOC_FREE(rec);
 173
 174         if (!NT_STATUS_IS_OK(status)) {
 175                 DEBUG(1,("session_claim: unable to create session id "
 176                          "record: %s\n", nt_errstr(status)));
 177                 return False;
 178         }
 179
 180         if (lp_utmp()) {
 181                 sys_utmp_claim(sessionid.username, sessionid.hostname,
 182                                sessionid.id_str, sessionid.id_num);
 183         }
 184
 185         vuser->session_keystr = talloc_strdup(vuser, keystr);
 186         if (!vuser->session_keystr) {
 187                 DEBUG(0, ("session_claim:  talloc_strdup() failed for session_keystr\n"));
 188                 return False;
 189         }
 190         return True;
 191 }
 192
 193 /********************************************************************
 194  called when a session is destroyed
 195 ********************************************************************/
 196
 197 void session_yield(struct user_struct *vuser)
 198 {
 199         struct sessionid sessionid;
 200         struct db_record *rec;
 201         TDB_DATA value;
 202
 203         if (!vuser->session_keystr) {
 204                 return;
 205         }
 206
 207         rec = sessionid_fetch_record(NULL, vuser->session_keystr);
 208         if (rec == NULL) {
 209                 return;
 210         }
 211
 212         value = dbwrap_record_get_value(rec);
 213
 214         if (value.dsize != sizeof(sessionid))
 215                 return;
 216
 217         memcpy(&sessionid, value.dptr, sizeof(sessionid));
 218
 219         if (lp_utmp()) {
 220                 sys_utmp_yield(sessionid.username, sessionid.hostname,
 221                                sessionid.id_str, sessionid.id_num);
 222         }
 223
 224         smb_pam_close_session(sessionid.username, sessionid.id_str,
 225                               sessionid.hostname);
 226
 227         dbwrap_record_delete(rec);
 228
 229         TALLOC_FREE(rec);
 230 }
 231
 232 /********************************************************************
 233 ********************************************************************/
 234
 235 struct session_list {
 236         TALLOC_CTX *mem_ctx;
 237         int count;
 238         struct sessionid *sessions;
 239 };
 240
 241 static int gather_sessioninfo(const char *key, struct sessionid *session,
 242                               void *private_data)
 243 {
 244         struct session_list *sesslist = (struct session_list *)private_data;
 245
 246         sesslist->sessions = talloc_realloc(
 247                 sesslist->mem_ctx, sesslist->sessions, struct sessionid,
 248                 sesslist->count+1);
 249
 250         if (!sesslist->sessions) {
 251                 sesslist->count = 0;
 252                 return -1;
 253         }
 254
 255         memcpy(&sesslist->sessions[sesslist->count], session,
 256                sizeof(struct sessionid));
 257
 258         sesslist->count++;
 259
 260         DEBUG(7, ("gather_sessioninfo session from %s@%s\n",
 261                   session->username, session->remote_machine));
 262
 263         return 0;
 264 }
 265
 266 /********************************************************************
 267 ********************************************************************/
 268
 269 int list_sessions(TALLOC_CTX *mem_ctx, struct sessionid **session_list)
 270 {
 271         struct session_list sesslist;
 272         NTSTATUS status;
 273
 274         sesslist.mem_ctx = mem_ctx;
 275         sesslist.count = 0;
 276         sesslist.sessions = NULL;
 277
 278         status = sessionid_traverse_read(gather_sessioninfo, (void *) &sesslist);
 279         if (!NT_STATUS_IS_OK(status)) {
 280                 DEBUG(3, ("Session traverse failed\n"));
 281                 SAFE_FREE(sesslist.sessions);
 282                 *session_list = NULL;
 283                 return 0;
 284         }
 285
 286         *session_list = sesslist.sessions;
 287         return sesslist.count;
 288 }