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(user_struct *vuser)
  37 {
  38         TDB_DATA data;
  39         int i = 0;
  40         struct sessionid sessionid;
  41         struct server_id pid = procid_self();
  42         fstring keystr;
  43         const char * hostname;
  44         struct db_record *rec;
  45         NTSTATUS status;
  46         char addr[INET6_ADDRSTRLEN];
  47
  48         vuser->session_keystr = NULL;
  49
  50         /* don't register sessions for the guest user - its just too
  51            expensive to go through pam session code for browsing etc */
  52         if (vuser->server_info->guest) {
  53                 return True;
  54         }
  55
  56         if (!sessionid_init()) {
  57                 return False;
  58         }
  59
  60         ZERO_STRUCT(sessionid);
  61
  62         data.dptr = NULL;
  63         data.dsize = 0;
  64
  65         if (lp_utmp()) {
  66
  67                 for (i=1;i<MAX_SESSION_ID;i++) {
  68
  69                         /*
  70                          * This is very inefficient and needs fixing -- vl
  71                          */
  72
  73                         struct server_id sess_pid;
  74
  75                         snprintf(keystr, sizeof(keystr), "ID/%d", i);
  76
  77                         rec = sessionid_fetch_record(NULL, keystr);
  78                         if (rec == NULL) {
  79                                 DEBUG(1, ("Could not lock \"%s\"\n", keystr));
  80                                 return False;
  81                         }
  82
  83                         if (rec->value.dsize != sizeof(sessionid)) {
  84                                 DEBUG(1, ("Re-using invalid record\n"));
  85                                 break;
  86                         }
  87
  88                         memcpy(&sess_pid,
  89                                ((char *)rec->value.dptr)
  90                                + offsetof(struct sessionid, pid),
  91                                sizeof(sess_pid));
  92
  93                         if (!process_exists(sess_pid)) {
  94                                 DEBUG(5, ("%s has died -- re-using session\n",
  95                                           procid_str_static(&sess_pid)));
  96                                 break;
  97                         }
  98
  99                         TALLOC_FREE(rec);
 100                 }
 101
 102                 if (i == MAX_SESSION_ID) {
 103                         SMB_ASSERT(rec == NULL);
 104                         DEBUG(1,("session_claim: out of session IDs "
 105                                  "(max is %d)\n", MAX_SESSION_ID));
 106                         return False;
 107                 }
 108
 109                 snprintf(sessionid.id_str, sizeof(sessionid.id_str),
 110                          SESSION_UTMP_TEMPLATE, i);
 111         } else
 112         {
 113                 snprintf(keystr, sizeof(keystr), "ID/%s/%u",
 114                          procid_str_static(&pid), vuser->vuid);
 115
 116                 rec = sessionid_fetch_record(NULL, keystr);
 117                 if (rec == NULL) {
 118                         DEBUG(1, ("Could not lock \"%s\"\n", keystr));
 119                         return False;
 120                 }
 121
 122                 snprintf(sessionid.id_str, sizeof(sessionid.id_str),
 123                          SESSION_TEMPLATE, (long unsigned int)sys_getpid(),
 124                          vuser->vuid);
 125         }
 126
 127         SMB_ASSERT(rec != NULL);
 128
 129         /* If 'hostname lookup' == yes, then do the DNS lookup.  This is
 130            needed because utmp and PAM both expect DNS names
 131
 132            client_name() handles this case internally.
 133         */
 134
 135         hostname = client_name(get_client_fd());
 136         if (strcmp(hostname, "UNKNOWN") == 0) {
 137                 hostname = client_addr(get_client_fd(),addr,sizeof(addr));
 138         }
 139
 140         fstrcpy(sessionid.username, vuser->server_info->unix_name);
 141         fstrcpy(sessionid.hostname, hostname);
 142         sessionid.id_num = i;  /* Only valid for utmp sessions */
 143         sessionid.pid = pid;
 144         sessionid.uid = vuser->server_info->utok.uid;
 145         sessionid.gid = vuser->server_info->utok.gid;
 146         fstrcpy(sessionid.remote_machine, get_remote_machine_name());
 147         fstrcpy(sessionid.ip_addr_str,
 148                 client_addr(get_client_fd(),addr,sizeof(addr)));
 149         sessionid.connect_start = time(NULL);
 150
 151         if (!smb_pam_claim_session(sessionid.username, sessionid.id_str,
 152                                    sessionid.hostname)) {
 153                 DEBUG(1,("pam_session rejected the session for %s [%s]\n",
 154                                 sessionid.username, sessionid.id_str));
 155
 156                 TALLOC_FREE(rec);
 157                 return False;
 158         }
 159
 160         data.dptr = (uint8 *)&sessionid;
 161         data.dsize = sizeof(sessionid);
 162
 163         status = rec->store(rec, data, TDB_REPLACE);
 164
 165         TALLOC_FREE(rec);
 166
 167         if (!NT_STATUS_IS_OK(status)) {
 168                 DEBUG(1,("session_claim: unable to create session id "
 169                          "record: %s\n", nt_errstr(status)));
 170                 return False;
 171         }
 172
 173         if (lp_utmp()) {
 174                 sys_utmp_claim(sessionid.username, sessionid.hostname,
 175                                sessionid.ip_addr_str,
 176                                sessionid.id_str, sessionid.id_num);
 177         }
 178
 179         vuser->session_keystr = talloc_strdup(vuser, keystr);
 180         if (!vuser->session_keystr) {
 181                 DEBUG(0, ("session_claim:  talloc_strdup() failed for session_keystr\n"));
 182                 return False;
 183         }
 184         return True;
 185 }
 186
 187 /********************************************************************
 188  called when a session is destroyed
 189 ********************************************************************/
 190
 191 void session_yield(user_struct *vuser)
 192 {
 193         struct sessionid sessionid;
 194         struct db_record *rec;
 195
 196         if (!vuser->session_keystr) {
 197                 return;
 198         }
 199
 200         rec = sessionid_fetch_record(NULL, vuser->session_keystr);
 201         if (rec == NULL) {
 202                 return;
 203         }
 204
 205         if (rec->value.dsize != sizeof(sessionid))
 206                 return;
 207
 208         memcpy(&sessionid, rec->value.dptr, sizeof(sessionid));
 209
 210         if (lp_utmp()) {
 211                 sys_utmp_yield(sessionid.username, sessionid.hostname,
 212                                sessionid.ip_addr_str,
 213                                sessionid.id_str, sessionid.id_num);
 214         }
 215
 216         smb_pam_close_session(sessionid.username, sessionid.id_str,
 217                               sessionid.hostname);
 218
 219         rec->delete_rec(rec);
 220
 221         TALLOC_FREE(rec);
 222 }
 223
 224 /********************************************************************
 225 ********************************************************************/
 226
 227 struct session_list {
 228         TALLOC_CTX *mem_ctx;
 229         int count;
 230         struct sessionid *sessions;
 231 };
 232
 233 static int gather_sessioninfo(const char *key, struct sessionid *session,
 234                               void *private_data)
 235 {
 236         struct session_list *sesslist = (struct session_list *)private_data;
 237
 238         sesslist->sessions = TALLOC_REALLOC_ARRAY(
 239                 sesslist->mem_ctx, sesslist->sessions, struct sessionid,
 240                 sesslist->count+1);
 241
 242         if (!sesslist->sessions) {
 243                 sesslist->count = 0;
 244                 return -1;
 245         }
 246
 247         memcpy(&sesslist->sessions[sesslist->count], session,
 248                sizeof(struct sessionid));
 249
 250         sesslist->count++;
 251
 252         DEBUG(7, ("gather_sessioninfo session from %s@%s\n",
 253                   session->username, session->remote_machine));
 254
 255         return 0;
 256 }
 257
 258 /********************************************************************
 259 ********************************************************************/
 260
 261 int list_sessions(TALLOC_CTX *mem_ctx, struct sessionid **session_list)
 262 {
 263         struct session_list sesslist;
 264         int ret;
 265
 266         sesslist.mem_ctx = mem_ctx;
 267         sesslist.count = 0;
 268         sesslist.sessions = NULL;
 269
 270         ret = sessionid_traverse_read(gather_sessioninfo, (void *) &sesslist);
 271         if (ret == -1) {
 272                 DEBUG(3, ("Session traverse failed\n"));
 273                 SAFE_FREE(sesslist.sessions);
 274                 *session_list = NULL;
 275                 return 0;
 276         }
 277
 278         *session_list = sesslist.sessions;
 279         return sesslist.count;
 280 }