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/globals.h"
  31
  32 /********************************************************************
  33  called when a session is created
  34 ********************************************************************/
  35
  36 bool session_claim(struct server_id pid, user_struct *vuser)
  37 {
  38         TDB_DATA data;
  39         int i = 0;
  40         struct sessionid sessionid;
  41         fstring keystr;
  42         const char * hostname;
  43         struct db_record *rec;
  44         NTSTATUS status;
  45         char addr[INET6_ADDRSTRLEN];
  46
  47         vuser->session_keystr = NULL;
  48
  49         /* don't register sessions for the guest user - its just too
  50            expensive to go through pam session code for browsing etc */
  51         if (vuser->server_info->guest) {
  52                 return True;
  53         }
  54
  55         if (!sessionid_init()) {
  56                 return False;
  57         }
  58
  59         ZERO_STRUCT(sessionid);
  60
  61         data.dptr = NULL;
  62         data.dsize = 0;
  63
  64         if (lp_utmp()) {
  65
  66                 for (i=1;i<MAX_SESSION_ID;i++) {
  67
  68                         /*
  69                          * This is very inefficient and needs fixing -- vl
  70                          */
  71
  72                         struct server_id sess_pid;
  73
  74                         snprintf(keystr, sizeof(keystr), "ID/%d", i);
  75
  76                         rec = sessionid_fetch_record(NULL, keystr);
  77                         if (rec == NULL) {
  78                                 DEBUG(1, ("Could not lock \"%s\"\n", keystr));
  79                                 return False;
  80                         }
  81
  82                         if (rec->value.dsize != sizeof(sessionid)) {
  83                                 DEBUG(1, ("Re-using invalid record\n"));
  84                                 break;
  85                         }
  86
  87                         memcpy(&sess_pid,
  88                                ((char *)rec->value.dptr)
  89                                + offsetof(struct sessionid, pid),
  90                                sizeof(sess_pid));
  91
  92                         if (!process_exists(sess_pid)) {
  93                                 DEBUG(5, ("%s has died -- re-using session\n",
  94                                           procid_str_static(&sess_pid)));
  95                                 break;
  96                         }
  97
  98                         TALLOC_FREE(rec);
  99                 }
 100
 101                 if (i == MAX_SESSION_ID) {
 102                         SMB_ASSERT(rec == NULL);
 103                         DEBUG(1,("session_claim: out of session IDs "
 104                                  "(max is %d)\n", MAX_SESSION_ID));
 105                         return False;
 106                 }
 107
 108                 snprintf(sessionid.id_str, sizeof(sessionid.id_str),
 109                          SESSION_UTMP_TEMPLATE, i);
 110         } else
 111         {
 112                 snprintf(keystr, sizeof(keystr), "ID/%s/%u",
 113                          procid_str_static(&pid), vuser->vuid);
 114
 115                 rec = sessionid_fetch_record(NULL, keystr);
 116                 if (rec == NULL) {
 117                         DEBUG(1, ("Could not lock \"%s\"\n", keystr));
 118                         return False;
 119                 }
 120
 121                 snprintf(sessionid.id_str, sizeof(sessionid.id_str),
 122                          SESSION_TEMPLATE, (long unsigned int)sys_getpid(),
 123                          vuser->vuid);
 124         }
 125
 126         SMB_ASSERT(rec != NULL);
 127
 128         /* If 'hostname lookup' == yes, then do the DNS lookup.  This is
 129            needed because utmp and PAM both expect DNS names
 130
 131            client_name() handles this case internally.
 132         */
 133
 134         hostname = client_name(get_client_fd());
 135         if (strcmp(hostname, "UNKNOWN") == 0) {
 136                 hostname = client_addr(get_client_fd(),addr,sizeof(addr));
 137         }
 138
 139         fstrcpy(sessionid.username, vuser->server_info->unix_name);
 140         fstrcpy(sessionid.hostname, hostname);
 141         sessionid.id_num = i;  /* Only valid for utmp sessions */
 142         sessionid.pid = pid;
 143         sessionid.uid = vuser->server_info->utok.uid;
 144         sessionid.gid = vuser->server_info->utok.gid;
 145         fstrcpy(sessionid.remote_machine, get_remote_machine_name());
 146         fstrcpy(sessionid.ip_addr_str,
 147                 client_addr(get_client_fd(),addr,sizeof(addr)));
 148         sessionid.connect_start = time(NULL);
 149
 150         if (!smb_pam_claim_session(sessionid.username, sessionid.id_str,
 151                                    sessionid.hostname)) {
 152                 DEBUG(1,("pam_session rejected the session for %s [%s]\n",
 153                                 sessionid.username, sessionid.id_str));
 154
 155                 TALLOC_FREE(rec);
 156                 return False;
 157         }
 158
 159         data.dptr = (uint8 *)&sessionid;
 160         data.dsize = sizeof(sessionid);
 161
 162         status = rec->store(rec, data, TDB_REPLACE);
 163
 164         TALLOC_FREE(rec);
 165
 166         if (!NT_STATUS_IS_OK(status)) {
 167                 DEBUG(1,("session_claim: unable to create session id "
 168                          "record: %s\n", nt_errstr(status)));
 169                 return False;
 170         }
 171
 172         if (lp_utmp()) {
 173                 sys_utmp_claim(sessionid.username, sessionid.hostname,
 174                                sessionid.ip_addr_str,
 175                                sessionid.id_str, sessionid.id_num);
 176         }
 177
 178         vuser->session_keystr = talloc_strdup(vuser, keystr);
 179         if (!vuser->session_keystr) {
 180                 DEBUG(0, ("session_claim:  talloc_strdup() failed for session_keystr\n"));
 181                 return False;
 182         }
 183         return True;
 184 }
 185
 186 /********************************************************************
 187  called when a session is destroyed
 188 ********************************************************************/
 189
 190 void session_yield(user_struct *vuser)
 191 {
 192         struct sessionid sessionid;
 193         struct db_record *rec;
 194
 195         if (!vuser->session_keystr) {
 196                 return;
 197         }
 198
 199         rec = sessionid_fetch_record(NULL, vuser->session_keystr);
 200         if (rec == NULL) {
 201                 return;
 202         }
 203
 204         if (rec->value.dsize != sizeof(sessionid))
 205                 return;
 206
 207         memcpy(&sessionid, rec->value.dptr, sizeof(sessionid));
 208
 209         if (lp_utmp()) {
 210                 sys_utmp_yield(sessionid.username, sessionid.hostname,
 211                                sessionid.ip_addr_str,
 212                                sessionid.id_str, sessionid.id_num);
 213         }
 214
 215         smb_pam_close_session(sessionid.username, sessionid.id_str,
 216                               sessionid.hostname);
 217
 218         rec->delete_rec(rec);
 219
 220         TALLOC_FREE(rec);
 221 }
 222
 223 /********************************************************************
 224 ********************************************************************/
 225
 226 struct session_list {
 227         TALLOC_CTX *mem_ctx;
 228         int count;
 229         struct sessionid *sessions;
 230 };
 231
 232 static int gather_sessioninfo(const char *key, struct sessionid *session,
 233                               void *private_data)
 234 {
 235         struct session_list *sesslist = (struct session_list *)private_data;
 236
 237         sesslist->sessions = TALLOC_REALLOC_ARRAY(
 238                 sesslist->mem_ctx, sesslist->sessions, struct sessionid,
 239                 sesslist->count+1);
 240
 241         if (!sesslist->sessions) {
 242                 sesslist->count = 0;
 243                 return -1;
 244         }
 245
 246         memcpy(&sesslist->sessions[sesslist->count], session,
 247                sizeof(struct sessionid));
 248
 249         sesslist->count++;
 250
 251         DEBUG(7, ("gather_sessioninfo session from %s@%s\n",
 252                   session->username, session->remote_machine));
 253
 254         return 0;
 255 }
 256
 257 /********************************************************************
 258 ********************************************************************/
 259
 260 int list_sessions(TALLOC_CTX *mem_ctx, struct sessionid **session_list)
 261 {
 262         struct session_list sesslist;
 263         int ret;
 264
 265         sesslist.mem_ctx = mem_ctx;
 266         sesslist.count = 0;
 267         sesslist.sessions = NULL;
 268
 269         ret = sessionid_traverse_read(gather_sessioninfo, (void *) &sesslist);
 270         if (ret == -1) {
 271                 DEBUG(3, ("Session traverse failed\n"));
 272                 SAFE_FREE(sesslist.sessions);
 273                 *session_list = NULL;
 274                 return 0;
 275         }
 276
 277         *session_list = sesslist.sessions;
 278         return sesslist.count;
 279 }