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 smbXsrv_session *session)
  44 {
  45         struct user_struct *vuser = session->compat;
  46         struct server_id pid = messaging_server_id(sconn->msg_ctx);
  47         TDB_DATA data;
  48         int i = 0;
  49         struct sessionid sessionid;
  50         fstring keystr;
  51         struct db_record *rec;
  52         NTSTATUS status;
  53         char *raddr;
  54
  55         vuser->session_keystr = NULL;
  56
  57         /* don't register sessions for the guest user - its just too
  58            expensive to go through pam session code for browsing etc */
  59         if (security_session_user_level(vuser->session_info, NULL) < SECURITY_USER) {
  60                 return True;
  61         }
  62
  63         if (!sessionid_init()) {
  64                 return False;
  65         }
  66
  67         ZERO_STRUCT(sessionid);
  68
  69         data.dptr = NULL;
  70         data.dsize = 0;
  71
  72         if (lp_utmp()) {
  73
  74                 for (i=1;i<MAX_SESSION_ID;i++) {
  75
  76                         /*
  77                          * This is very inefficient and needs fixing -- vl
  78                          */
  79
  80                         struct server_id sess_pid;
  81                         TDB_DATA value;
  82
  83                         snprintf(keystr, sizeof(keystr), "ID/%d", i);
  84
  85                         rec = sessionid_fetch_record(NULL, keystr);
  86                         if (rec == NULL) {
  87                                 DEBUG(1, ("Could not lock \"%s\"\n", keystr));
  88                                 return False;
  89                         }
  90
  91                         value = dbwrap_record_get_value(rec);
  92
  93                         if (value.dsize != sizeof(sessionid)) {
  94                                 DEBUG(1, ("Re-using invalid record\n"));
  95                                 break;
  96                         }
  97
  98                         memcpy(&sess_pid,
  99                                ((char *)value.dptr)
 100                                + offsetof(struct sessionid, pid),
 101                                sizeof(sess_pid));
 102
 103                         if (!process_exists(sess_pid)) {
 104                                 DEBUG(5, ("%s has died -- re-using session\n",
 105                                           procid_str_static(&sess_pid)));
 106                                 break;
 107                         }
 108
 109                         TALLOC_FREE(rec);
 110                 }
 111
 112                 if (i == MAX_SESSION_ID) {
 113                         SMB_ASSERT(rec == NULL);
 114                         DEBUG(1,("session_claim: out of session IDs "
 115                                  "(max is %d)\n", MAX_SESSION_ID));
 116                         return False;
 117                 }
 118
 119                 snprintf(sessionid.id_str, sizeof(sessionid.id_str),
 120                          SESSION_UTMP_TEMPLATE, i);
 121         } else
 122         {
 123                 snprintf(keystr, sizeof(keystr), "ID/%s/%llu",
 124                          procid_str_static(&pid),
 125                          (unsigned long long)vuser->vuid);
 126
 127                 rec = sessionid_fetch_record(NULL, keystr);
 128                 if (rec == NULL) {
 129                         DEBUG(1, ("Could not lock \"%s\"\n", keystr));
 130                         return False;
 131                 }
 132
 133                 snprintf(sessionid.id_str, sizeof(sessionid.id_str),
 134                          SESSION_TEMPLATE, (long unsigned int)getpid(),
 135                          (unsigned long long)vuser->vuid);
 136         }
 137
 138         SMB_ASSERT(rec != NULL);
 139
 140         raddr = tsocket_address_inet_addr_string(sconn->remote_address,
 141                                                  talloc_tos());
 142         if (raddr == NULL) {
 143                 return false;
 144         }
 145
 146         /* Make clear that we require the optional unix_token in the source3 code */
 147         SMB_ASSERT(vuser->session_info->unix_token);
 148
 149         fstrcpy(sessionid.username, vuser->session_info->unix_info->unix_name);
 150         fstrcpy(sessionid.hostname, sconn->remote_hostname);
 151         sessionid.id_num = i;  /* Only valid for utmp sessions */
 152         sessionid.pid = pid;
 153         sessionid.uid = vuser->session_info->unix_token->uid;
 154         sessionid.gid = vuser->session_info->unix_token->gid;
 155         fstrcpy(sessionid.remote_machine, get_remote_machine_name());
 156         fstrcpy(sessionid.ip_addr_str, raddr);
 157         sessionid.connect_start = time(NULL);
 158
 159         if (!smb_pam_claim_session(sessionid.username, sessionid.id_str,
 160                                    sessionid.hostname)) {
 161                 DEBUG(1,("pam_session rejected the session for %s [%s]\n",
 162                                 sessionid.username, sessionid.id_str));
 163
 164                 TALLOC_FREE(rec);
 165                 return False;
 166         }
 167
 168         data.dptr = (uint8 *)&sessionid;
 169         data.dsize = sizeof(sessionid);
 170
 171         status = dbwrap_record_store(rec, data, TDB_REPLACE);
 172
 173         TALLOC_FREE(rec);
 174
 175         if (!NT_STATUS_IS_OK(status)) {
 176                 DEBUG(1,("session_claim: unable to create session id "
 177                          "record: %s\n", nt_errstr(status)));
 178                 return False;
 179         }
 180
 181         if (lp_utmp()) {
 182                 sys_utmp_claim(sessionid.username, sessionid.hostname,
 183                                sessionid.id_str, sessionid.id_num);
 184         }
 185
 186         vuser->session_keystr = talloc_strdup(vuser, keystr);
 187         if (!vuser->session_keystr) {
 188                 DEBUG(0, ("session_claim:  talloc_strdup() failed for session_keystr\n"));
 189                 return False;
 190         }
 191         return True;
 192 }
 193
 194 /********************************************************************
 195  called when a session is destroyed
 196 ********************************************************************/
 197
 198 void session_yield(struct smbXsrv_session *session)
 199 {
 200         struct user_struct *vuser = session->compat;
 201         struct sessionid sessionid;
 202         struct db_record *rec;
 203         TDB_DATA value;
 204
 205         if (!vuser->session_keystr) {
 206                 return;
 207         }
 208
 209         rec = sessionid_fetch_record(NULL, vuser->session_keystr);
 210         if (rec == NULL) {
 211                 return;
 212         }
 213
 214         value = dbwrap_record_get_value(rec);
 215
 216         if (value.dsize != sizeof(sessionid))
 217                 return;
 218
 219         memcpy(&sessionid, value.dptr, sizeof(sessionid));
 220
 221         if (lp_utmp()) {
 222                 sys_utmp_yield(sessionid.username, sessionid.hostname,
 223                                sessionid.id_str, sessionid.id_num);
 224         }
 225
 226         smb_pam_close_session(sessionid.username, sessionid.id_str,
 227                               sessionid.hostname);
 228
 229         dbwrap_record_delete(rec);
 230
 231         TALLOC_FREE(rec);
 232 }
 233
 234 /********************************************************************
 235 ********************************************************************/
 236
 237 struct session_list {
 238         TALLOC_CTX *mem_ctx;
 239         int count;
 240         struct sessionid *sessions;
 241 };
 242
 243 static int gather_sessioninfo(const char *key, struct sessionid *session,
 244                               void *private_data)
 245 {
 246         struct session_list *sesslist = (struct session_list *)private_data;
 247
 248         sesslist->sessions = talloc_realloc(
 249                 sesslist->mem_ctx, sesslist->sessions, struct sessionid,
 250                 sesslist->count+1);
 251
 252         if (!sesslist->sessions) {
 253                 sesslist->count = 0;
 254                 return -1;
 255         }
 256
 257         memcpy(&sesslist->sessions[sesslist->count], session,
 258                sizeof(struct sessionid));
 259
 260         sesslist->count++;
 261
 262         DEBUG(7, ("gather_sessioninfo session from %s@%s\n",
 263                   session->username, session->remote_machine));
 264
 265         return 0;
 266 }
 267
 268 /********************************************************************
 269 ********************************************************************/
 270
 271 int list_sessions(TALLOC_CTX *mem_ctx, struct sessionid **session_list)
 272 {
 273         struct session_list sesslist;
 274         NTSTATUS status;
 275
 276         sesslist.mem_ctx = mem_ctx;
 277         sesslist.count = 0;
 278         sesslist.sessions = NULL;
 279
 280         status = sessionid_traverse_read(gather_sessioninfo, (void *) &sesslist);
 281         if (!NT_STATUS_IS_OK(status)) {
 282                 DEBUG(3, ("Session traverse failed\n"));
 283                 SAFE_FREE(sesslist.sessions);
 284                 *session_list = NULL;
 285                 return 0;
 286         }
 287
 288         *session_list = sesslist.sessions;
 289         return sesslist.count;
 290 }