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 ********************************************************************/
  34
  35 static struct db_context *session_db_ctx(void)
  36 {
  37         if (session_db_ctx_ptr)
  38                 return session_db_ctx_ptr;
  39
  40         session_db_ctx_ptr = db_open(NULL, lock_path("sessionid.tdb"), 0,
  41                                      TDB_CLEAR_IF_FIRST|TDB_INCOMPATIBLE_HASH|TDB_DEFAULT,
  42                                      O_RDWR | O_CREAT, 0644);
  43         return session_db_ctx_ptr;
  44 }
  45
  46 bool session_init(void)
  47 {
  48         if (session_db_ctx() == NULL) {
  49                 DEBUG(1,("session_init: failed to open sessionid tdb\n"));
  50                 return False;
  51         }
  52
  53         return True;
  54 }
  55
  56 /********************************************************************
  57  called when a session is created
  58 ********************************************************************/
  59
  60 bool session_claim(user_struct *vuser)
  61 {
  62         TDB_DATA key, data;
  63         int i = 0;
  64         struct sessionid sessionid;
  65         struct server_id pid = procid_self();
  66         fstring keystr;
  67         const char * hostname;
  68         struct db_context *ctx;
  69         struct db_record *rec;
  70         NTSTATUS status;
  71         char addr[INET6_ADDRSTRLEN];
  72
  73         vuser->session_keystr = NULL;
  74
  75         /* don't register sessions for the guest user - its just too
  76            expensive to go through pam session code for browsing etc */
  77         if (vuser->server_info->guest) {
  78                 return True;
  79         }
  80
  81         if (!(ctx = session_db_ctx())) {
  82                 return False;
  83         }
  84
  85         ZERO_STRUCT(sessionid);
  86
  87         data.dptr = NULL;
  88         data.dsize = 0;
  89
  90         if (lp_utmp()) {
  91
  92                 for (i=1;i<MAX_SESSION_ID;i++) {
  93
  94                         /*
  95                          * This is very inefficient and needs fixing -- vl
  96                          */
  97
  98                         struct server_id sess_pid;
  99
 100                         snprintf(keystr, sizeof(keystr), "ID/%d", i);
 101                         key = string_term_tdb_data(keystr);
 102
 103                         rec = ctx->fetch_locked(ctx, NULL, key);
 104
 105                         if (rec == NULL) {
 106                                 DEBUG(1, ("Could not lock \"%s\"\n", keystr));
 107                                 return False;
 108                         }
 109
 110                         if (rec->value.dsize != sizeof(sessionid)) {
 111                                 DEBUG(1, ("Re-using invalid record\n"));
 112                                 break;
 113                         }
 114
 115                         memcpy(&sess_pid,
 116                                ((char *)rec->value.dptr)
 117                                + offsetof(struct sessionid, pid),
 118                                sizeof(sess_pid));
 119
 120                         if (!process_exists(sess_pid)) {
 121                                 DEBUG(5, ("%s has died -- re-using session\n",
 122                                           procid_str_static(&sess_pid)));
 123                                 break;
 124                         }
 125
 126                         TALLOC_FREE(rec);
 127                 }
 128
 129                 if (i == MAX_SESSION_ID) {
 130                         SMB_ASSERT(rec == NULL);
 131                         DEBUG(1,("session_claim: out of session IDs "
 132                                  "(max is %d)\n", MAX_SESSION_ID));
 133                         return False;
 134                 }
 135
 136                 snprintf(sessionid.id_str, sizeof(sessionid.id_str),
 137                          SESSION_UTMP_TEMPLATE, i);
 138         } else
 139         {
 140                 snprintf(keystr, sizeof(keystr), "ID/%s/%u",
 141                          procid_str_static(&pid), vuser->vuid);
 142                 key = string_term_tdb_data(keystr);
 143
 144                 rec = ctx->fetch_locked(ctx, NULL, key);
 145
 146                 if (rec == NULL) {
 147                         DEBUG(1, ("Could not lock \"%s\"\n", keystr));
 148                         return False;
 149                 }
 150
 151                 snprintf(sessionid.id_str, sizeof(sessionid.id_str),
 152                          SESSION_TEMPLATE, (long unsigned int)sys_getpid(),
 153                          vuser->vuid);
 154         }
 155
 156         SMB_ASSERT(rec != NULL);
 157
 158         /* If 'hostname lookup' == yes, then do the DNS lookup.  This is
 159            needed because utmp and PAM both expect DNS names
 160
 161            client_name() handles this case internally.
 162         */
 163
 164         hostname = client_name(get_client_fd());
 165         if (strcmp(hostname, "UNKNOWN") == 0) {
 166                 hostname = client_addr(get_client_fd(),addr,sizeof(addr));
 167         }
 168
 169         fstrcpy(sessionid.username, vuser->server_info->unix_name);
 170         fstrcpy(sessionid.hostname, hostname);
 171         sessionid.id_num = i;  /* Only valid for utmp sessions */
 172         sessionid.pid = pid;
 173         sessionid.uid = vuser->server_info->utok.uid;
 174         sessionid.gid = vuser->server_info->utok.gid;
 175         fstrcpy(sessionid.remote_machine, get_remote_machine_name());
 176         fstrcpy(sessionid.ip_addr_str,
 177                 client_addr(get_client_fd(),addr,sizeof(addr)));
 178         sessionid.connect_start = time(NULL);
 179
 180         if (!smb_pam_claim_session(sessionid.username, sessionid.id_str,
 181                                    sessionid.hostname)) {
 182                 DEBUG(1,("pam_session rejected the session for %s [%s]\n",
 183                                 sessionid.username, sessionid.id_str));
 184
 185                 TALLOC_FREE(rec);
 186                 return False;
 187         }
 188
 189         data.dptr = (uint8 *)&sessionid;
 190         data.dsize = sizeof(sessionid);
 191
 192         status = rec->store(rec, data, TDB_REPLACE);
 193
 194         TALLOC_FREE(rec);
 195
 196         if (!NT_STATUS_IS_OK(status)) {
 197                 DEBUG(1,("session_claim: unable to create session id "
 198                          "record: %s\n", nt_errstr(status)));
 199                 return False;
 200         }
 201
 202         if (lp_utmp()) {
 203                 sys_utmp_claim(sessionid.username, sessionid.hostname,
 204                                sessionid.ip_addr_str,
 205                                sessionid.id_str, sessionid.id_num);
 206         }
 207
 208         vuser->session_keystr = talloc_strdup(vuser, keystr);
 209         if (!vuser->session_keystr) {
 210                 DEBUG(0, ("session_claim:  talloc_strdup() failed for session_keystr\n"));
 211                 return False;
 212         }
 213         return True;
 214 }
 215
 216 /********************************************************************
 217  called when a session is destroyed
 218 ********************************************************************/
 219
 220 void session_yield(user_struct *vuser)
 221 {
 222         TDB_DATA key;
 223         struct sessionid sessionid;
 224         struct db_context *ctx;
 225         struct db_record *rec;
 226
 227         if (!(ctx = session_db_ctx())) return;
 228
 229         if (!vuser->session_keystr) {
 230                 return;
 231         }
 232
 233         key = string_term_tdb_data(vuser->session_keystr);
 234
 235         if (!(rec = ctx->fetch_locked(ctx, NULL, key))) {
 236                 return;
 237         }
 238
 239         if (rec->value.dsize != sizeof(sessionid))
 240                 return;
 241
 242         memcpy(&sessionid, rec->value.dptr, sizeof(sessionid));
 243
 244         if (lp_utmp()) {
 245                 sys_utmp_yield(sessionid.username, sessionid.hostname,
 246                                sessionid.ip_addr_str,
 247                                sessionid.id_str, sessionid.id_num);
 248         }
 249
 250         smb_pam_close_session(sessionid.username, sessionid.id_str,
 251                               sessionid.hostname);
 252
 253         rec->delete_rec(rec);
 254
 255         TALLOC_FREE(rec);
 256 }
 257
 258 /********************************************************************
 259 ********************************************************************/
 260
 261 static bool session_traverse(int (*fn)(struct db_record *db,
 262                                        void *private_data),
 263                              void *private_data)
 264 {
 265         struct db_context *ctx;
 266
 267         if (!(ctx = session_db_ctx())) {
 268                 DEBUG(3, ("No tdb opened\n"));
 269                 return False;
 270         }
 271
 272         ctx->traverse_read(ctx, fn, private_data);
 273         return True;
 274 }
 275
 276 /********************************************************************
 277 ********************************************************************/
 278
 279 struct session_list {
 280         TALLOC_CTX *mem_ctx;
 281         int count;
 282         struct sessionid *sessions;
 283 };
 284
 285 static int gather_sessioninfo(struct db_record *rec, void *state)
 286 {
 287         struct session_list *sesslist = (struct session_list *) state;
 288         const struct sessionid *current =
 289                 (const struct sessionid *) rec->value.dptr;
 290
 291         sesslist->sessions = TALLOC_REALLOC_ARRAY(
 292                 sesslist->mem_ctx, sesslist->sessions, struct sessionid,
 293                 sesslist->count+1);
 294
 295         if (!sesslist->sessions) {
 296                 sesslist->count = 0;
 297                 return -1;
 298         }
 299
 300         memcpy(&sesslist->sessions[sesslist->count], current,
 301                sizeof(struct sessionid));
 302
 303         sesslist->count++;
 304
 305         DEBUG(7,("gather_sessioninfo session from %s@%s\n",
 306                  current->username, current->remote_machine));
 307
 308         return 0;
 309 }
 310
 311 /********************************************************************
 312 ********************************************************************/
 313
 314 int list_sessions(TALLOC_CTX *mem_ctx, struct sessionid **session_list)
 315 {
 316         struct session_list sesslist;
 317
 318         sesslist.mem_ctx = mem_ctx;
 319         sesslist.count = 0;
 320         sesslist.sessions = NULL;
 321
 322         if (!session_traverse(gather_sessioninfo, (void *) &sesslist)) {
 323                 DEBUG(3, ("Session traverse failed\n"));
 324                 SAFE_FREE(sesslist.sessions);
 325                 *session_list = NULL;
 326                 return 0;
 327         }
 328
 329         *session_list = sesslist.sessions;
 330         return sesslist.count;
 331 }