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 smbXsrv_session *session)
  44 {
  45         struct user_struct *vuser = session->compat;
  46         struct smbd_server_connection *sconn = session->connection->sconn;
  47         struct server_id pid = messaging_server_id(sconn->msg_ctx);
  48         TDB_DATA data;
  49         int i = 0;
  50         struct sessionid sessionid;
  51         fstring keystr;
  52         struct db_record *rec;
  53         NTSTATUS status;
  54         char *raddr;
  55
  56         vuser->session_keystr = NULL;
  57
  58         /* don't register sessions for the guest user - its just too
  59            expensive to go through pam session code for browsing etc */
  60         if (security_session_user_level(vuser->session_info, NULL) < SECURITY_USER) {
  61                 return True;
  62         }
  63
  64         if (!sessionid_init()) {
  65                 return False;
  66         }
  67
  68         ZERO_STRUCT(sessionid);
  69
  70         data.dptr = NULL;
  71         data.dsize = 0;
  72
  73         if (lp_utmp()) {
  74
  75                 for (i=1;i<MAX_SESSION_ID;i++) {
  76
  77                         /*
  78                          * This is very inefficient and needs fixing -- vl
  79                          */
  80
  81                         struct server_id sess_pid;
  82                         TDB_DATA value;
  83
  84                         snprintf(keystr, sizeof(keystr), "ID/%d", i);
  85
  86                         rec = sessionid_fetch_record(NULL, keystr);
  87                         if (rec == NULL) {
  88                                 DEBUG(1, ("Could not lock \"%s\"\n", keystr));
  89                                 return False;
  90                         }
  91
  92                         value = dbwrap_record_get_value(rec);
  93
  94                         if (value.dsize != sizeof(sessionid)) {
  95                                 DEBUG(1, ("Re-using invalid record\n"));
  96                                 break;
  97                         }
  98
  99                         memcpy(&sess_pid,
 100                                ((char *)value.dptr)
 101                                + offsetof(struct sessionid, pid),
 102                                sizeof(sess_pid));
 103
 104                         if (!process_exists(sess_pid)) {
 105                                 DEBUG(5, ("%s has died -- re-using session\n",
 106                                           procid_str_static(&sess_pid)));
 107                                 break;
 108                         }
 109
 110                         TALLOC_FREE(rec);
 111                 }
 112
 113                 if (i == MAX_SESSION_ID) {
 114                         SMB_ASSERT(rec == NULL);
 115                         DEBUG(1,("session_claim: out of session IDs "
 116                                  "(max is %d)\n", MAX_SESSION_ID));
 117                         return False;
 118                 }
 119
 120                 snprintf(sessionid.id_str, sizeof(sessionid.id_str),
 121                          SESSION_UTMP_TEMPLATE, i);
 122         } else
 123         {
 124                 snprintf(keystr, sizeof(keystr), "ID/%s/%llu",
 125                          procid_str_static(&pid),
 126                          (unsigned long long)vuser->vuid);
 127
 128                 rec = sessionid_fetch_record(NULL, keystr);
 129                 if (rec == NULL) {
 130                         DEBUG(1, ("Could not lock \"%s\"\n", keystr));
 131                         return False;
 132                 }
 133
 134                 snprintf(sessionid.id_str, sizeof(sessionid.id_str),
 135                          SESSION_TEMPLATE, (long unsigned int)getpid(),
 136                          (unsigned long long)vuser->vuid);
 137         }
 138
 139         SMB_ASSERT(rec != NULL);
 140
 141         raddr = tsocket_address_inet_addr_string(session->connection->remote_address,
 142                                                  talloc_tos());
 143         if (raddr == NULL) {
 144                 return false;
 145         }
 146
 147         /* Make clear that we require the optional unix_token in the source3 code */
 148         SMB_ASSERT(vuser->session_info->unix_token);
 149
 150         fstrcpy(sessionid.username, vuser->session_info->unix_info->unix_name);
 151         fstrcpy(sessionid.hostname, sconn->remote_hostname);
 152         sessionid.id_num = i;  /* Only valid for utmp sessions */
 153         sessionid.pid = pid;
 154         sessionid.uid = vuser->session_info->unix_token->uid;
 155         sessionid.gid = vuser->session_info->unix_token->gid;
 156         fstrcpy(sessionid.remote_machine, get_remote_machine_name());
 157         fstrcpy(sessionid.ip_addr_str, raddr);
 158         sessionid.connect_start = time(NULL);
 159
 160         if (!smb_pam_claim_session(sessionid.username, sessionid.id_str,
 161                                    sessionid.hostname)) {
 162                 DEBUG(1,("pam_session rejected the session for %s [%s]\n",
 163                                 sessionid.username, sessionid.id_str));
 164
 165                 TALLOC_FREE(rec);
 166                 return False;
 167         }
 168
 169         data.dptr = (uint8 *)&sessionid;
 170         data.dsize = sizeof(sessionid);
 171
 172         status = dbwrap_record_store(rec, data, TDB_REPLACE);
 173
 174         TALLOC_FREE(rec);
 175
 176         if (!NT_STATUS_IS_OK(status)) {
 177                 DEBUG(1,("session_claim: unable to create session id "
 178                          "record: %s\n", nt_errstr(status)));
 179                 return False;
 180         }
 181
 182         if (lp_utmp()) {
 183                 sys_utmp_claim(sessionid.username, sessionid.hostname,
 184                                sessionid.id_str, sessionid.id_num);
 185         }
 186
 187         vuser->session_keystr = talloc_strdup(vuser, keystr);
 188         if (!vuser->session_keystr) {
 189                 DEBUG(0, ("session_claim:  talloc_strdup() failed for session_keystr\n"));
 190                 return False;
 191         }
 192         return True;
 193 }
 194
 195 /********************************************************************
 196  called when a session is destroyed
 197 ********************************************************************/
 198
 199 void session_yield(struct smbXsrv_session *session)
 200 {
 201         struct user_struct *vuser = session->compat;
 202         struct sessionid sessionid;
 203         struct db_record *rec;
 204         TDB_DATA value;
 205
 206         if (!vuser->session_keystr) {
 207                 return;
 208         }
 209
 210         rec = sessionid_fetch_record(NULL, vuser->session_keystr);
 211         if (rec == NULL) {
 212                 return;
 213         }
 214
 215         value = dbwrap_record_get_value(rec);
 216
 217         if (value.dsize != sizeof(sessionid))
 218                 return;
 219
 220         memcpy(&sessionid, value.dptr, sizeof(sessionid));
 221
 222         if (lp_utmp()) {
 223                 sys_utmp_yield(sessionid.username, sessionid.hostname,
 224                                sessionid.id_str, sessionid.id_num);
 225         }
 226
 227         smb_pam_close_session(sessionid.username, sessionid.id_str,
 228                               sessionid.hostname);
 229
 230         dbwrap_record_delete(rec);
 231
 232         TALLOC_FREE(rec);
 233 }
 234
 235 /********************************************************************
 236 ********************************************************************/
 237
 238 struct session_list {
 239         TALLOC_CTX *mem_ctx;
 240         int count;
 241         struct sessionid *sessions;
 242 };
 243
 244 static int gather_sessioninfo(const char *key, struct sessionid *session,
 245                               void *private_data)
 246 {
 247         struct session_list *sesslist = (struct session_list *)private_data;
 248
 249         sesslist->sessions = talloc_realloc(
 250                 sesslist->mem_ctx, sesslist->sessions, struct sessionid,
 251                 sesslist->count+1);
 252
 253         if (!sesslist->sessions) {
 254                 sesslist->count = 0;
 255                 return -1;
 256         }
 257
 258         memcpy(&sesslist->sessions[sesslist->count], session,
 259                sizeof(struct sessionid));
 260
 261         sesslist->count++;
 262
 263         DEBUG(7, ("gather_sessioninfo session from %s@%s\n",
 264                   session->username, session->remote_machine));
 265
 266         return 0;
 267 }
 268
 269 /********************************************************************
 270 ********************************************************************/
 271
 272 int list_sessions(TALLOC_CTX *mem_ctx, struct sessionid **session_list)
 273 {
 274         struct session_list sesslist;
 275         NTSTATUS status;
 276
 277         sesslist.mem_ctx = mem_ctx;
 278         sesslist.count = 0;
 279         sesslist.sessions = NULL;
 280
 281         status = sessionid_traverse_read(gather_sessioninfo, (void *) &sesslist);
 282         if (!NT_STATUS_IS_OK(status)) {
 283                 DEBUG(3, ("Session traverse failed\n"));
 284                 SAFE_FREE(sesslist.sessions);
 285                 *session_list = NULL;
 286                 return 0;
 287         }
 288
 289         *session_list = sesslist.sessions;
 290         return sesslist.count;
 291 }