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.h"
  33 #include "session.h"
  34 #include "auth.h"
  35 #include "../lib/tsocket/tsocket.h"
  36
  37 /********************************************************************
  38  called when a session is created
  39 ********************************************************************/
  40
  41 bool session_claim(struct smbd_server_connection *sconn, user_struct *vuser)
  42 {
  43         struct server_id pid = sconn_server_id(sconn);
  44         TDB_DATA data;
  45         int i = 0;
  46         struct sessionid sessionid;
  47         fstring keystr;
  48         struct db_record *rec;
  49         NTSTATUS status;
  50         char *raddr;
  51
  52         vuser->session_keystr = NULL;
  53
  54         /* don't register sessions for the guest user - its just too
  55            expensive to go through pam session code for browsing etc */
  56         if (vuser->session_info->unix_info->guest) {
  57                 return True;
  58         }
  59
  60         if (!sessionid_init()) {
  61                 return False;
  62         }
  63
  64         ZERO_STRUCT(sessionid);
  65
  66         data.dptr = NULL;
  67         data.dsize = 0;
  68
  69         if (lp_utmp()) {
  70
  71                 for (i=1;i<MAX_SESSION_ID;i++) {
  72
  73                         /*
  74                          * This is very inefficient and needs fixing -- vl
  75                          */
  76
  77                         struct server_id sess_pid;
  78
  79                         snprintf(keystr, sizeof(keystr), "ID/%d", i);
  80
  81                         rec = sessionid_fetch_record(NULL, keystr);
  82                         if (rec == NULL) {
  83                                 DEBUG(1, ("Could not lock \"%s\"\n", keystr));
  84                                 return False;
  85                         }
  86
  87                         if (rec->value.dsize != sizeof(sessionid)) {
  88                                 DEBUG(1, ("Re-using invalid record\n"));
  89                                 break;
  90                         }
  91
  92                         memcpy(&sess_pid,
  93                                ((char *)rec->value.dptr)
  94                                + offsetof(struct sessionid, pid),
  95                                sizeof(sess_pid));
  96
  97                         if (!process_exists(sess_pid)) {
  98                                 DEBUG(5, ("%s has died -- re-using session\n",
  99                                           procid_str_static(&sess_pid)));
 100                                 break;
 101                         }
 102
 103                         TALLOC_FREE(rec);
 104                 }
 105
 106                 if (i == MAX_SESSION_ID) {
 107                         SMB_ASSERT(rec == NULL);
 108                         DEBUG(1,("session_claim: out of session IDs "
 109                                  "(max is %d)\n", MAX_SESSION_ID));
 110                         return False;
 111                 }
 112
 113                 snprintf(sessionid.id_str, sizeof(sessionid.id_str),
 114                          SESSION_UTMP_TEMPLATE, i);
 115         } else
 116         {
 117                 snprintf(keystr, sizeof(keystr), "ID/%s/%u",
 118                          procid_str_static(&pid), vuser->vuid);
 119
 120                 rec = sessionid_fetch_record(NULL, keystr);
 121                 if (rec == NULL) {
 122                         DEBUG(1, ("Could not lock \"%s\"\n", keystr));
 123                         return False;
 124                 }
 125
 126                 snprintf(sessionid.id_str, sizeof(sessionid.id_str),
 127                          SESSION_TEMPLATE, (long unsigned int)sys_getpid(),
 128                          vuser->vuid);
 129         }
 130
 131         SMB_ASSERT(rec != NULL);
 132
 133         raddr = tsocket_address_inet_addr_string(sconn->remote_address,
 134                                                  talloc_tos());
 135         if (raddr == NULL) {
 136                 return false;
 137         }
 138
 139         /* Make clear that we require the optional unix_token in the source3 code */
 140         SMB_ASSERT(vuser->session_info->unix_token);
 141
 142         fstrcpy(sessionid.username, vuser->session_info->unix_info->unix_name);
 143         fstrcpy(sessionid.hostname, sconn->remote_hostname);
 144         sessionid.id_num = i;  /* Only valid for utmp sessions */
 145         sessionid.pid = pid;
 146         sessionid.uid = vuser->session_info->unix_token->uid;
 147         sessionid.gid = vuser->session_info->unix_token->gid;
 148         fstrcpy(sessionid.remote_machine, get_remote_machine_name());
 149         fstrcpy(sessionid.ip_addr_str, raddr);
 150         sessionid.connect_start = time(NULL);
 151
 152         if (!smb_pam_claim_session(sessionid.username, sessionid.id_str,
 153                                    sessionid.hostname)) {
 154                 DEBUG(1,("pam_session rejected the session for %s [%s]\n",
 155                                 sessionid.username, sessionid.id_str));
 156
 157                 TALLOC_FREE(rec);
 158                 return False;
 159         }
 160
 161         data.dptr = (uint8 *)&sessionid;
 162         data.dsize = sizeof(sessionid);
 163
 164         status = rec->store(rec, data, TDB_REPLACE);
 165
 166         TALLOC_FREE(rec);
 167
 168         if (!NT_STATUS_IS_OK(status)) {
 169                 DEBUG(1,("session_claim: unable to create session id "
 170                          "record: %s\n", nt_errstr(status)));
 171                 return False;
 172         }
 173
 174         if (lp_utmp()) {
 175                 sys_utmp_claim(sessionid.username, sessionid.hostname,
 176                                sessionid.ip_addr_str,
 177                                sessionid.id_str, sessionid.id_num);
 178         }
 179
 180         vuser->session_keystr = talloc_strdup(vuser, keystr);
 181         if (!vuser->session_keystr) {
 182                 DEBUG(0, ("session_claim:  talloc_strdup() failed for session_keystr\n"));
 183                 return False;
 184         }
 185         return True;
 186 }
 187
 188 /********************************************************************
 189  called when a session is destroyed
 190 ********************************************************************/
 191
 192 void session_yield(user_struct *vuser)
 193 {
 194         struct sessionid sessionid;
 195         struct db_record *rec;
 196
 197         if (!vuser->session_keystr) {
 198                 return;
 199         }
 200
 201         rec = sessionid_fetch_record(NULL, vuser->session_keystr);
 202         if (rec == NULL) {
 203                 return;
 204         }
 205
 206         if (rec->value.dsize != sizeof(sessionid))
 207                 return;
 208
 209         memcpy(&sessionid, rec->value.dptr, sizeof(sessionid));
 210
 211         if (lp_utmp()) {
 212                 sys_utmp_yield(sessionid.username, sessionid.hostname,
 213                                sessionid.ip_addr_str,
 214                                sessionid.id_str, sessionid.id_num);
 215         }
 216
 217         smb_pam_close_session(sessionid.username, sessionid.id_str,
 218                               sessionid.hostname);
 219
 220         rec->delete_rec(rec);
 221
 222         TALLOC_FREE(rec);
 223 }
 224
 225 /********************************************************************
 226 ********************************************************************/
 227
 228 struct session_list {
 229         TALLOC_CTX *mem_ctx;
 230         int count;
 231         struct sessionid *sessions;
 232 };
 233
 234 static int gather_sessioninfo(const char *key, struct sessionid *session,
 235                               void *private_data)
 236 {
 237         struct session_list *sesslist = (struct session_list *)private_data;
 238
 239         sesslist->sessions = talloc_realloc(
 240                 sesslist->mem_ctx, sesslist->sessions, struct sessionid,
 241                 sesslist->count+1);
 242
 243         if (!sesslist->sessions) {
 244                 sesslist->count = 0;
 245                 return -1;
 246         }
 247
 248         memcpy(&sesslist->sessions[sesslist->count], session,
 249                sizeof(struct sessionid));
 250
 251         sesslist->count++;
 252
 253         DEBUG(7, ("gather_sessioninfo session from %s@%s\n",
 254                   session->username, session->remote_machine));
 255
 256         return 0;
 257 }
 258
 259 /********************************************************************
 260 ********************************************************************/
 261
 262 int list_sessions(TALLOC_CTX *mem_ctx, struct sessionid **session_list)
 263 {
 264         struct session_list sesslist;
 265         int ret;
 266
 267         sesslist.mem_ctx = mem_ctx;
 268         sesslist.count = 0;
 269         sesslist.sessions = NULL;
 270
 271         ret = sessionid_traverse_read(gather_sessioninfo, (void *) &sesslist);
 272         if (ret < 0) {
 273                 DEBUG(3, ("Session traverse failed\n"));
 274                 SAFE_FREE(sesslist.sessions);
 275                 *session_list = NULL;
 276                 return 0;
 277         }
 278
 279         *session_list = sesslist.sessions;
 280         return sesslist.count;
 281 }