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, uint32_t 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         uint32_t cnum;
 102         int find_offset = 1;
 103
 104         if (sconn->using_smb2) {
 105                 /* SMB2 */
 106                 if (!(conn=talloc_zero(NULL, connection_struct)) ||
 107                     !(conn->params = talloc(conn, struct share_params))) {
 108                         DEBUG(0,("TALLOC_ZERO() failed!\n"));
 109                         TALLOC_FREE(conn);
 110                         return NULL;
 111                 }
 112                 conn->sconn = sconn;
 113
 114                 DLIST_ADD(sconn->connections, conn);
 115                 sconn->num_connections++;
 116
 117                 return conn;
 118         }
 119
 120         /* SMB1 */
 121 find_again:
 122         i = bitmap_find(sconn->smb1.tcons.bmap, find_offset);
 123
 124         if (i == -1) {
 125                 /* Expand the connections bitmap. */
 126                 int             oldsz = sconn->smb1.tcons.bmap->n;
 127                 int             newsz = sconn->smb1.tcons.bmap->n +
 128                                         BITMAP_BLOCK_SZ;
 129                 struct bitmap * nbmap;
 130
 131                 if (newsz <= oldsz) {
 132                         /* Integer wrap. */
 133                         DEBUG(0,("ERROR! Out of connection structures\n"));
 134                         return NULL;
 135                 }
 136
 137                 DEBUG(4,("resizing connections bitmap from %d to %d\n",
 138                         oldsz, newsz));
 139
 140                 nbmap = bitmap_talloc(sconn, newsz);
 141                 if (!nbmap) {
 142                         DEBUG(0,("ERROR! malloc fail.\n"));
 143                         return NULL;
 144                 }
 145
 146                 bitmap_copy(nbmap, sconn->smb1.tcons.bmap);
 147                 TALLOC_FREE(sconn->smb1.tcons.bmap);
 148
 149                 sconn->smb1.tcons.bmap = nbmap;
 150                 find_offset = oldsz; /* Start next search in the new portion. */
 151
 152                 goto find_again;
 153         }
 154
 155         /* The bitmap position is used below as the connection number
 156          * conn->cnum). This ends up as the TID field in the SMB header,
 157          * which is limited to 16 bits (we skip 0xffff which is the
 158          * NULL TID).
 159          */
 160         cnum = i + CNUM_OFFSET;
 161         if (cnum >= 0xFFFF) {
 162                 DEBUG(0, ("Maximum connection limit reached\n"));
 163                 return NULL;
 164         }
 165
 166         if (!(conn=talloc_zero(NULL, connection_struct)) ||
 167             !(conn->params = talloc(conn, struct share_params))) {
 168                 DEBUG(0,("TALLOC_ZERO() failed!\n"));
 169                 TALLOC_FREE(conn);
 170                 return NULL;
 171         }
 172         conn->sconn = sconn;
 173         conn->cnum = cnum;
 174         conn->force_group_gid = (gid_t)-1;
 175
 176         bitmap_set(sconn->smb1.tcons.bmap, i);
 177
 178         string_set(&conn->connectpath,"");
 179         string_set(&conn->origpath,"");
 180
 181         DLIST_ADD(sconn->connections, conn);
 182         sconn->num_connections++;
 183
 184         return conn;
 185 }
 186
 187 /****************************************************************************
 188  Clear a vuid out of the connection's vuid cache
 189 ****************************************************************************/
 190
 191 static void conn_clear_vuid_cache(connection_struct *conn, uint64_t vuid)
 192 {
 193         int i;
 194
 195         for (i=0; i<VUID_CACHE_SIZE; i++) {
 196                 struct vuid_cache_entry *ent;
 197
 198                 ent = &conn->vuid_cache.array[i];
 199
 200                 if (ent->vuid == vuid) {
 201                         ent->vuid = UID_FIELD_INVALID;
 202                         /*
 203                          * We need to keep conn->session_info around
 204                          * if it's equal to ent->session_info as a SMBulogoff
 205                          * is often followed by a SMBtdis (with an invalid
 206                          * vuid). The debug code (or regular code in
 207                          * vfs_full_audit) wants to refer to the
 208                          * conn->session_info pointer to print debug
 209                          * statements. Theoretically this is a bug,
 210                          * as once the vuid is gone the session_info
 211                          * on the conn struct isn't valid any more,
 212                          * but there's enough code that assumes
 213                          * conn->session_info is never null that
 214                          * it's easier to hold onto the old pointer
 215                          * until we get a new sessionsetupX.
 216                          * As everything is hung off the
 217                          * conn pointer as a talloc context we're not
 218                          * leaking memory here. See bug #6315. JRA.
 219                          */
 220                         if (conn->session_info == ent->session_info) {
 221                                 ent->session_info = NULL;
 222                         } else {
 223                                 TALLOC_FREE(ent->session_info);
 224                         }
 225                         ent->read_only = False;
 226                 }
 227         }
 228 }
 229
 230 /****************************************************************************
 231  Clear a vuid out of the validity cache, and as the 'owner' of a connection.
 232
 233  Called from invalidate_vuid()
 234 ****************************************************************************/
 235
 236 void conn_clear_vuid_caches(struct smbd_server_connection *sconn, uint64_t vuid)
 237 {
 238         connection_struct *conn;
 239
 240         for (conn=sconn->connections; conn;conn=conn->next) {
 241                 if (conn->vuid == vuid) {
 242                         conn->vuid = UID_FIELD_INVALID;
 243                 }
 244                 conn_clear_vuid_cache(conn, vuid);
 245         }
 246 }
 247
 248 /****************************************************************************
 249  Free a conn structure - internal part.
 250 ****************************************************************************/
 251
 252 static void conn_free_internal(connection_struct *conn)
 253 {
 254         vfs_handle_struct *handle = NULL, *thandle = NULL;
 255         struct trans_state *state = NULL;
 256
 257         /* Free vfs_connection_struct */
 258         handle = conn->vfs_handles;
 259         while(handle) {
 260                 thandle = handle->next;
 261                 DLIST_REMOVE(conn->vfs_handles, handle);
 262                 if (handle->free_data)
 263                         handle->free_data(&handle->data);
 264                 handle = thandle;
 265         }
 266
 267         /* Free any pending transactions stored on this conn. */
 268         for (state = conn->pending_trans; state; state = state->next) {
 269                 /* state->setup is a talloc child of state. */
 270                 SAFE_FREE(state->param);
 271                 SAFE_FREE(state->data);
 272         }
 273
 274         free_namearray(conn->veto_list);
 275         free_namearray(conn->hide_list);
 276         free_namearray(conn->veto_oplock_list);
 277         free_namearray(conn->aio_write_behind_list);
 278
 279         string_free(&conn->connectpath);
 280         string_free(&conn->origpath);
 281
 282         ZERO_STRUCTP(conn);
 283         talloc_destroy(conn);
 284 }
 285
 286 /****************************************************************************
 287  Free a conn structure.
 288 ****************************************************************************/
 289
 290 void conn_free(connection_struct *conn)
 291 {
 292         if (conn->sconn == NULL) {
 293                 conn_free_internal(conn);
 294                 return;
 295         }
 296
 297         if (!conn->sconn->using_smb2 &&
 298             conn->sconn->smb1.tcons.bmap != NULL &&
 299             conn->cnum >= CNUM_OFFSET &&
 300             conn->cnum < 0xFFFF)
 301         {
 302                 int i = conn->cnum - CNUM_OFFSET;
 303                 /*
 304                  * Can be NULL for fake connections created by
 305                  * create_conn_struct()
 306                  */
 307                 bitmap_clear(conn->sconn->smb1.tcons.bmap, i);
 308         }
 309
 310         DLIST_REMOVE(conn->sconn->connections, conn);
 311         SMB_ASSERT(conn->sconn->num_connections > 0);
 312         conn->sconn->num_connections--;
 313
 314         conn_free_internal(conn);
 315 }