source/utils/smbfilter.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 2
   4    SMB filter/socket plugin
   5    Copyright (C) Andrew Tridgell 1999
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20 */
  21
  22 #include "includes.h"
  23 #include "smb.h"
  24
  25 #define SECURITY_MASK 0
  26 #define SECURITY_SET  0
  27
  28 /* this forces non-unicode */
  29 #define CAPABILITY_MASK (CAP_NT_SMBS | CAP_RPC_REMOTE_APIS)
  30 #define CAPABILITY_SET  0
  31
  32 /* and non-unicode for the client too */
  33 #define CLI_CAPABILITY_MASK 0
  34 #define CLI_CAPABILITY_SET  0
  35
  36 static char *netbiosname;
  37 static char packet[BUFFER_SIZE];
  38
  39 static void filter_reply(char *buf)
  40 {
  41         int msg_type = CVAL(buf,0);
  42         int type = CVAL(buf,smb_com);
  43         unsigned x;
  44
  45         if (msg_type) return;
  46
  47         switch (type) {
  48
  49         case SMBnegprot:
  50                 /* force the security bits */
  51                 x = CVAL(buf, smb_vwv1);
  52                 x = (x | SECURITY_SET) & ~SECURITY_MASK;
  53                 SCVAL(buf, smb_vwv1, x);
  54
  55                 /* force the capabilities */
  56                 x = IVAL(buf,smb_vwv9+1);
  57                 x = (x | CAPABILITY_SET) & ~CAPABILITY_MASK;
  58                 SIVAL(buf, smb_vwv9+1, x);
  59                 break;
  60
  61         }
  62 }
  63
  64 static void filter_request(char *buf)
  65 {
  66         int msg_type = CVAL(buf,0);
  67         int type = CVAL(buf,smb_com);
  68         pstring name1,name2;
  69         unsigned x;
  70
  71         if (msg_type) {
  72                 /* it's a netbios special */
  73                 switch (msg_type) {
  74                 case 0x81:
  75                         /* session request */
  76                         name_extract(buf,4,name1);
  77                         name_extract(buf,4 + name_len(buf + 4),name2);
  78                         DEBUG(0,("sesion_request: %s -> %s\n",
  79                                  name1, name2));
  80                         if (netbiosname) {
  81                                 /* replace the destination netbios name */
  82                                 name_mangle(netbiosname, buf+4, 0x20);
  83                         }
  84                 }
  85                 return;
  86         }
  87
  88         /* it's an ordinary SMB request */
  89         switch (type) {
  90         case SMBsesssetupX:
  91                 /* force the client capabilities */
  92                 x = IVAL(buf,smb_vwv11);
  93                 x = (x | CLI_CAPABILITY_SET) & ~CLI_CAPABILITY_MASK;
  94                 SIVAL(buf, smb_vwv11, x);
  95                 break;
  96         }
  97
  98 }
  99
 100
 101 static void filter_child(int c, struct in_addr dest_ip)
 102 {
 103         int s;
 104
 105         /* we have a connection from a new client, now connect to the server */
 106         s = open_socket_out(SOCK_STREAM, &dest_ip, 139, LONG_CONNECT_TIMEOUT);
 107
 108         if (s == -1) {
 109                 DEBUG(0,("Unable to connect to %s\n", inet_ntoa(dest_ip)));
 110                 exit(1);
 111         }
 112
 113         while (c != -1 || s != -1) {
 114                 fd_set fds;
 115                 int num;
 116
 117                 FD_ZERO(&fds);
 118                 if (s != -1) FD_SET(s, &fds);
 119                 if (c != -1) FD_SET(c, &fds);
 120
 121                 num = sys_select_intr(MAX(s+1, c+1),&fds,NULL,NULL,NULL);
 122                 if (num <= 0) continue;
 123
 124                 if (c != -1 && FD_ISSET(c, &fds)) {
 125                         if (!receive_smb(c, packet, 0)) {
 126                                 DEBUG(0,("client closed connection\n"));
 127                                 exit(0);
 128                         }
 129                         filter_request(packet);
 130                         if (!send_smb(s, packet)) {
 131                                 DEBUG(0,("server is dead\n"));
 132                                 exit(1);
 133                         }
 134                 }
 135                 if (s != -1 && FD_ISSET(s, &fds)) {
 136                         if (!receive_smb(s, packet, 0)) {
 137                                 DEBUG(0,("server closed connection\n"));
 138                                 exit(0);
 139                         }
 140                         filter_reply(packet);
 141                         if (!send_smb(c, packet)) {
 142                                 DEBUG(0,("client is dead\n"));
 143                                 exit(1);
 144                         }
 145                 }
 146         }
 147         DEBUG(0,("Connection closed\n"));
 148         exit(0);
 149 }
 150
 151
 152 static void start_filter(char *desthost)
 153 {
 154         int s, c;
 155         struct in_addr dest_ip;
 156
 157         CatchChild();
 158
 159         /* start listening on port 139 locally */
 160         s = open_socket_in(SOCK_STREAM, 139, 0, 0, True);
 161
 162         if (s == -1) {
 163                 DEBUG(0,("bind failed\n"));
 164                 exit(1);
 165         }
 166
 167         if (listen(s, 5) == -1) {
 168                 DEBUG(0,("listen failed\n"));
 169         }
 170
 171         if (!resolve_name(desthost, &dest_ip, 0x20)) {
 172                 DEBUG(0,("Unable to resolve host %s\n", desthost));
 173                 exit(1);
 174         }
 175
 176         while (1) {
 177                 fd_set fds;
 178                 int num;
 179                 struct sockaddr addr;
 180                 socklen_t in_addrlen = sizeof(addr);
 181
 182                 FD_ZERO(&fds);
 183                 FD_SET(s, &fds);
 184
 185                 num = sys_select_intr(s+1,&fds,NULL,NULL,NULL);
 186                 if (num > 0) {
 187                         c = accept(s, &addr, &in_addrlen);
 188                         if (c != -1) {
 189                                 if (fork() == 0) {
 190                                         close(s);
 191                                         filter_child(c, dest_ip);
 192                                         exit(0);
 193                                 } else {
 194                                         close(c);
 195                                 }
 196                         }
 197                 }
 198         }
 199 }
 200
 201
 202 int main(int argc, char *argv[])
 203 {
 204         char *desthost;
 205         pstring configfile;
 206
 207         TimeInit();
 208
 209         setup_logging(argv[0],True);
 210
 211         charset_initialise();
 212
 213         pstrcpy(configfile,CONFIGFILE);
 214
 215         if (argc < 2) {
 216                 fprintf(stderr,"smbfilter <desthost> <netbiosname>\n");
 217                 exit(1);
 218         }
 219
 220         desthost = argv[1];
 221         if (argc > 2) {
 222                 netbiosname = argv[2];
 223         }
 224
 225         if (!lp_load(configfile,True,False,False)) {
 226                 DEBUG(0,("Unable to load config file\n"));
 227         }
 228
 229         start_filter(desthost);
 230         return 0;
 231 }