source3/smbd/conn.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Manage connections_struct structures
   4    Copyright (C) Andrew Tridgell 1998
   5    Copyright (C) Alexander Bokovoy 2002
   6    Copyright (C) Jeremy Allison 2010
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 #include "includes.h"
  23 #include "smbd/smbd.h"
  24 #include "smbd/globals.h"
  25 #include "lib/util/bitmap.h"
  26
  27 /* The connections bitmap is expanded in increments of BITMAP_BLOCK_SZ. The
  28  * maximum size of the bitmap is the largest positive integer, but you will hit
  29  * the "max connections" limit, looong before that.
  30  */
  31
  32 #define BITMAP_BLOCK_SZ 128
  33
  34 /****************************************************************************
  35  Init the conn structures.
  36 ****************************************************************************/
  37
  38 void conn_init(struct smbd_server_connection *sconn)
  39 {
  40         sconn->smb1.tcons.bmap = bitmap_talloc(sconn, BITMAP_BLOCK_SZ);
  41 }
  42
  43 /****************************************************************************
  44  Return the number of open connections.
  45 ****************************************************************************/
  46
  47 int conn_num_open(struct smbd_server_connection *sconn)
  48 {
  49         return sconn->num_connections;
  50 }
  51
  52 /****************************************************************************
  53  Check if a snum is in use.
  54 ****************************************************************************/
  55
  56 bool conn_snum_used(struct smbd_server_connection *sconn,
  57                     int snum)
  58 {
  59         struct connection_struct *conn;
  60
  61         for (conn=sconn->connections; conn; conn=conn->next) {
  62                 if (conn->params->service == snum) {
  63                         return true;
  64                 }
  65         }
  66
  67         return false;
  68 }
  69
  70 /****************************************************************************
  71  Find a conn given a cnum.
  72 ****************************************************************************/
  73
  74 connection_struct *conn_find(struct smbd_server_connection *sconn,unsigned cnum)
  75 {
  76         size_t count=0;
  77         struct connection_struct *conn;
  78
  79         for (conn=sconn->connections; conn; conn=conn->next,count++) {
  80                 if (conn->cnum == cnum) {
  81                         if (count > 10) {
  82                                 DLIST_PROMOTE(sconn->connections, conn);
  83                         }
  84                         return conn;
  85                 }
  86         }
  87
  88         return NULL;
  89 }
  90
  91 /****************************************************************************
  92  Find first available connection slot, starting from a random position.
  93  The randomisation stops problems with the server dieing and clients
  94  thinking the server is still available.
  95 ****************************************************************************/
  96
  97 connection_struct *conn_new(struct smbd_server_connection *sconn)
  98 {
  99         connection_struct *conn;
 100         int i;
 101         int find_offset = 1;
 102
 103         if (sconn->using_smb2) {
 104                 /* SMB2 */
 105                 if (!(conn=talloc_zero(NULL, connection_struct)) ||
 106                     !(conn->params = talloc(conn, struct share_params))) {
 107                         DEBUG(0,("TALLOC_ZERO() failed!\n"));
 108                         TALLOC_FREE(conn);
 109                         return NULL;
 110                 }
 111                 conn->sconn = sconn;
 112
 113                 DLIST_ADD(sconn->connections, conn);
 114                 sconn->num_connections++;
 115
 116                 return conn;
 117         }
 118
 119         /* SMB1 */
 120 find_again:
 121         i = bitmap_find(sconn->smb1.tcons.bmap, find_offset);
 122
 123         if (i == -1) {
 124                 /* Expand the connections bitmap. */
 125                 int             oldsz = sconn->smb1.tcons.bmap->n;
 126                 int             newsz = sconn->smb1.tcons.bmap->n +
 127                                         BITMAP_BLOCK_SZ;
 128                 struct bitmap * nbmap;
 129
 130                 if (newsz <= oldsz) {
 131                         /* Integer wrap. */
 132                         DEBUG(0,("ERROR! Out of connection structures\n"));
 133                         return NULL;
 134                 }
 135
 136                 DEBUG(4,("resizing connections bitmap from %d to %d\n",
 137                         oldsz, newsz));
 138
 139                 nbmap = bitmap_talloc(sconn, newsz);
 140                 if (!nbmap) {
 141                         DEBUG(0,("ERROR! malloc fail.\n"));
 142                         return NULL;
 143                 }
 144
 145                 bitmap_copy(nbmap, sconn->smb1.tcons.bmap);
 146                 TALLOC_FREE(sconn->smb1.tcons.bmap);
 147
 148                 sconn->smb1.tcons.bmap = nbmap;
 149                 find_offset = oldsz; /* Start next search in the new portion. */
 150
 151                 goto find_again;
 152         }
 153
 154         /* The bitmap position is used below as the connection number
 155          * conn->cnum). This ends up as the TID field in the SMB header,
 156          * which is limited to 16 bits (we skip 0xffff which is the
 157          * NULL TID).
 158          */
 159         if (i > 65534) {
 160                 DEBUG(0, ("Maximum connection limit reached\n"));
 161                 return NULL;
 162         }
 163
 164         if (!(conn=talloc_zero(NULL, connection_struct)) ||
 165             !(conn->params = talloc(conn, struct share_params))) {
 166                 DEBUG(0,("TALLOC_ZERO() failed!\n"));
 167                 TALLOC_FREE(conn);
 168                 return NULL;
 169         }
 170         conn->sconn = sconn;
 171         conn->cnum = i;
 172         conn->force_group_gid = (gid_t)-1;
 173
 174         bitmap_set(sconn->smb1.tcons.bmap, i);
 175
 176         string_set(&conn->connectpath,"");
 177         string_set(&conn->origpath,"");
 178
 179         DLIST_ADD(sconn->connections, conn);
 180         sconn->num_connections++;
 181
 182         return conn;
 183 }
 184
 185 /****************************************************************************
 186  Clear a vuid out of the connection's vuid cache
 187 ****************************************************************************/
 188
 189 static void conn_clear_vuid_cache(connection_struct *conn, uint16_t vuid)
 190 {
 191         int i;
 192
 193         for (i=0; i<VUID_CACHE_SIZE; i++) {
 194                 struct vuid_cache_entry *ent;
 195
 196                 ent = &conn->vuid_cache.array[i];
 197
 198                 if (ent->vuid == vuid) {
 199                         ent->vuid = UID_FIELD_INVALID;
 200                         /*
 201                          * We need to keep conn->session_info around
 202                          * if it's equal to ent->session_info as a SMBulogoff
 203                          * is often followed by a SMBtdis (with an invalid
 204                          * vuid). The debug code (or regular code in
 205                          * vfs_full_audit) wants to refer to the
 206                          * conn->session_info pointer to print debug
 207                          * statements. Theoretically this is a bug,
 208                          * as once the vuid is gone the session_info
 209                          * on the conn struct isn't valid any more,
 210                          * but there's enough code that assumes
 211                          * conn->session_info is never null that
 212                          * it's easier to hold onto the old pointer
 213                          * until we get a new sessionsetupX.
 214                          * As everything is hung off the
 215                          * conn pointer as a talloc context we're not
 216                          * leaking memory here. See bug #6315. JRA.
 217                          */
 218                         if (conn->session_info == ent->session_info) {
 219                                 ent->session_info = NULL;
 220                         } else {
 221                                 TALLOC_FREE(ent->session_info);
 222                         }
 223                         ent->read_only = False;
 224                 }
 225         }
 226 }
 227
 228 /****************************************************************************
 229  Clear a vuid out of the validity cache, and as the 'owner' of a connection.
 230
 231  Called from invalidate_vuid()
 232 ****************************************************************************/
 233
 234 void conn_clear_vuid_caches(struct smbd_server_connection *sconn,uint16_t vuid)
 235 {
 236         connection_struct *conn;
 237
 238         for (conn=sconn->connections; conn;conn=conn->next) {
 239                 if (conn->vuid == vuid) {
 240                         conn->vuid = UID_FIELD_INVALID;
 241                 }
 242                 conn_clear_vuid_cache(conn, vuid);
 243         }
 244 }
 245
 246 /****************************************************************************
 247  Free a conn structure - internal part.
 248 ****************************************************************************/
 249
 250 static void conn_free_internal(connection_struct *conn)
 251 {
 252         vfs_handle_struct *handle = NULL, *thandle = NULL;
 253         struct trans_state *state = NULL;
 254
 255         /* Free vfs_connection_struct */
 256         handle = conn->vfs_handles;
 257         while(handle) {
 258                 thandle = handle->next;
 259                 DLIST_REMOVE(conn->vfs_handles, handle);
 260                 if (handle->free_data)
 261                         handle->free_data(&handle->data);
 262                 handle = thandle;
 263         }
 264
 265         /* Free any pending transactions stored on this conn. */
 266         for (state = conn->pending_trans; state; state = state->next) {
 267                 /* state->setup is a talloc child of state. */
 268                 SAFE_FREE(state->param);
 269                 SAFE_FREE(state->data);
 270         }
 271
 272         free_namearray(conn->veto_list);
 273         free_namearray(conn->hide_list);
 274         free_namearray(conn->veto_oplock_list);
 275         free_namearray(conn->aio_write_behind_list);
 276
 277         string_free(&conn->connectpath);
 278         string_free(&conn->origpath);
 279
 280         ZERO_STRUCTP(conn);
 281         talloc_destroy(conn);
 282 }
 283
 284 /****************************************************************************
 285  Free a conn structure.
 286 ****************************************************************************/
 287
 288 void conn_free(connection_struct *conn)
 289 {
 290         if (conn->sconn == NULL) {
 291                 conn_free_internal(conn);
 292                 return;
 293         }
 294
 295         if (!conn->sconn->using_smb2 &&
 296             conn->sconn->smb1.tcons.bmap != NULL) {
 297                 /*
 298                  * Can be NULL for fake connections created by
 299                  * create_conn_struct()
 300                  */
 301                 bitmap_clear(conn->sconn->smb1.tcons.bmap, conn->cnum);
 302         }
 303
 304         DLIST_REMOVE(conn->sconn->connections, conn);
 305         SMB_ASSERT(conn->sconn->num_connections > 0);
 306         conn->sconn->num_connections--;
 307
 308         conn_free_internal(conn);
 309 }