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                         TDB_DATA value;
  80
  81                         snprintf(keystr, sizeof(keystr), "ID/%d", i);
  82
  83                         rec = sessionid_fetch_record(NULL, keystr);
  84                         if (rec == NULL) {
  85                                 DEBUG(1, ("Could not lock \"%s\"\n", keystr));
  86                                 return False;
  87                         }
  88
  89                         value = dbwrap_record_get_value(rec);
  90
  91                         if (value.dsize != sizeof(sessionid)) {
  92                                 DEBUG(1, ("Re-using invalid record\n"));
  93                                 break;
  94                         }
  95
  96                         memcpy(&sess_pid,
  97                                ((char *)value.dptr)
  98                                + offsetof(struct sessionid, pid),
  99                                sizeof(sess_pid));
 100
 101                         if (!process_exists(sess_pid)) {
 102                                 DEBUG(5, ("%s has died -- re-using session\n",
 103                                           procid_str_static(&sess_pid)));
 104                                 break;
 105                         }
 106
 107                         TALLOC_FREE(rec);
 108                 }
 109
 110                 if (i == MAX_SESSION_ID) {
 111                         SMB_ASSERT(rec == NULL);
 112                         DEBUG(1,("session_claim: out of session IDs "
 113                                  "(max is %d)\n", MAX_SESSION_ID));
 114                         return False;
 115                 }
 116
 117                 snprintf(sessionid.id_str, sizeof(sessionid.id_str),
 118                          SESSION_UTMP_TEMPLATE, i);
 119         } else
 120         {
 121                 snprintf(keystr, sizeof(keystr), "ID/%s/%u",
 122                          procid_str_static(&pid), vuser->vuid);
 123
 124                 rec = sessionid_fetch_record(NULL, keystr);
 125                 if (rec == NULL) {
 126                         DEBUG(1, ("Could not lock \"%s\"\n", keystr));
 127                         return False;
 128                 }
 129
 130                 snprintf(sessionid.id_str, sizeof(sessionid.id_str),
 131                          SESSION_TEMPLATE, (long unsigned int)sys_getpid(),
 132                          vuser->vuid);
 133         }
 134
 135         SMB_ASSERT(rec != NULL);
 136
 137         raddr = tsocket_address_inet_addr_string(sconn->remote_address,
 138                                                  talloc_tos());
 139         if (raddr == NULL) {
 140                 return false;
 141         }
 142
 143         /* Make clear that we require the optional unix_token in the source3 code */
 144         SMB_ASSERT(vuser->session_info->unix_token);
 145
 146         fstrcpy(sessionid.username, vuser->session_info->unix_info->unix_name);
 147         fstrcpy(sessionid.hostname, sconn->remote_hostname);
 148         sessionid.id_num = i;  /* Only valid for utmp sessions */
 149         sessionid.pid = pid;
 150         sessionid.uid = vuser->session_info->unix_token->uid;
 151         sessionid.gid = vuser->session_info->unix_token->gid;
 152         fstrcpy(sessionid.remote_machine, get_remote_machine_name());
 153         fstrcpy(sessionid.ip_addr_str, raddr);
 154         sessionid.connect_start = time(NULL);
 155
 156         if (!smb_pam_claim_session(sessionid.username, sessionid.id_str,
 157                                    sessionid.hostname)) {
 158                 DEBUG(1,("pam_session rejected the session for %s [%s]\n",
 159                                 sessionid.username, sessionid.id_str));
 160
 161                 TALLOC_FREE(rec);
 162                 return False;
 163         }
 164
 165         data.dptr = (uint8 *)&sessionid;
 166         data.dsize = sizeof(sessionid);
 167
 168         status = dbwrap_record_store(rec, data, TDB_REPLACE);
 169
 170         TALLOC_FREE(rec);
 171
 172         if (!NT_STATUS_IS_OK(status)) {
 173                 DEBUG(1,("session_claim: unable to create session id "
 174                          "record: %s\n", nt_errstr(status)));
 175                 return False;
 176         }
 177
 178         if (lp_utmp()) {
 179                 sys_utmp_claim(sessionid.username, sessionid.hostname,
 180                                sessionid.ip_addr_str,
 181                                sessionid.id_str, sessionid.id_num);
 182         }
 183
 184         vuser->session_keystr = talloc_strdup(vuser, keystr);
 185         if (!vuser->session_keystr) {
 186                 DEBUG(0, ("session_claim:  talloc_strdup() failed for session_keystr\n"));
 187                 return False;
 188         }
 189         return True;
 190 }
 191
 192 /********************************************************************
 193  called when a session is destroyed
 194 ********************************************************************/
 195
 196 void session_yield(user_struct *vuser)
 197 {
 198         struct sessionid sessionid;
 199         struct db_record *rec;
 200         TDB_DATA value;
 201
 202         if (!vuser->session_keystr) {
 203                 return;
 204         }
 205
 206         rec = sessionid_fetch_record(NULL, vuser->session_keystr);
 207         if (rec == NULL) {
 208                 return;
 209         }
 210
 211         value = dbwrap_record_get_value(rec);
 212
 213         if (value.dsize != sizeof(sessionid))
 214                 return;
 215
 216         memcpy(&sessionid, value.dptr, sizeof(sessionid));
 217
 218         if (lp_utmp()) {
 219                 sys_utmp_yield(sessionid.username, sessionid.hostname,
 220                                sessionid.ip_addr_str,
 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 }