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 extern int DEBUGLEVEL;
  40
  41 static void filter_reply(char *buf)
  42 {
  43         int msg_type = CVAL(buf,0);
  44         int type = CVAL(buf,smb_com);
  45         unsigned x;
  46
  47         if (msg_type) return;
  48
  49         switch (type) {
  50
  51         case SMBnegprot:
  52                 /* force the security bits */
  53                 x = CVAL(buf, smb_vwv1);
  54                 x = (x | SECURITY_SET) & ~SECURITY_MASK;
  55                 SCVAL(buf, smb_vwv1, x);
  56
  57                 /* force the capabilities */
  58                 x = IVAL(buf,smb_vwv9+1);
  59                 x = (x | CAPABILITY_SET) & ~CAPABILITY_MASK;
  60                 SIVAL(buf, smb_vwv9+1, x);
  61                 break;
  62
  63         }
  64 }
  65
  66 static void filter_request(char *buf)
  67 {
  68         int msg_type = CVAL(buf,0);
  69         int type = CVAL(buf,smb_com);
  70         pstring name1,name2;
  71         unsigned x;
  72
  73         if (msg_type) {
  74                 /* it's a netbios special */
  75                 switch (msg_type) {
  76                 case 0x81:
  77                         /* session request */
  78                         name_extract(buf,4,name1);
  79                         name_extract(buf,4 + name_len(buf + 4),name2);
  80                         DEBUG(0,("sesion_request: %s -> %s\n",
  81                                  name1, name2));
  82                         if (netbiosname) {
  83                                 /* replace the destination netbios name */
  84                                 name_mangle(netbiosname, buf+4, 0x20);
  85                         }
  86                 }
  87                 return;
  88         }
  89
  90         /* it's an ordinary SMB request */
  91         switch (type) {
  92         case SMBsesssetupX:
  93                 /* force the client capabilities */
  94                 x = IVAL(buf,smb_vwv11);
  95                 x = (x | CLI_CAPABILITY_SET) & ~CLI_CAPABILITY_MASK;
  96                 SIVAL(buf, smb_vwv11, x);
  97                 break;
  98         }
  99
 100 }
 101
 102
 103 static void filter_child(int c, struct in_addr dest_ip)
 104 {
 105         int s;
 106
 107         /* we have a connection from a new client, now connect to the server */
 108         s = open_socket_out(SOCK_STREAM, &dest_ip, 139, LONG_CONNECT_TIMEOUT);
 109
 110         if (s == -1) {
 111                 DEBUG(0,("Unable to connect to %s\n", inet_ntoa(dest_ip)));
 112                 exit(1);
 113         }
 114
 115         while (c != -1 || s != -1) {
 116                 fd_set fds;
 117                 int num;
 118
 119                 FD_ZERO(&fds);
 120                 if (s != -1) FD_SET(s, &fds);
 121                 if (c != -1) FD_SET(c, &fds);
 122
 123                 num = sys_select_intr(MAX(s+1, c+1),&fds,NULL);
 124                 if (num <= 0) continue;
 125
 126                 if (c != -1 && FD_ISSET(c, &fds)) {
 127                         if (!receive_smb(c, packet, 0)) {
 128                                 DEBUG(0,("client closed connection\n"));
 129                                 exit(0);
 130                         }
 131                         filter_request(packet);
 132                         if (!send_smb(s, packet)) {
 133                                 DEBUG(0,("server is dead\n"));
 134                                 exit(1);
 135                         }
 136                 }
 137                 if (s != -1 && FD_ISSET(s, &fds)) {
 138                         if (!receive_smb(s, packet, 0)) {
 139                                 DEBUG(0,("server closed connection\n"));
 140                                 exit(0);
 141                         }
 142                         filter_reply(packet);
 143                         if (!send_smb(c, packet)) {
 144                                 DEBUG(0,("client is dead\n"));
 145                                 exit(1);
 146                         }
 147                 }
 148         }
 149         DEBUG(0,("Connection closed\n"));
 150         exit(0);
 151 }
 152
 153
 154 static void start_filter(char *desthost)
 155 {
 156         int s, c;
 157         struct in_addr dest_ip;
 158
 159         CatchChild();
 160
 161         /* start listening on port 139 locally */
 162         s = open_socket_in(SOCK_STREAM, 139, 0, 0, True);
 163
 164         if (s == -1) {
 165                 DEBUG(0,("bind failed\n"));
 166                 exit(1);
 167         }
 168
 169         if (listen(s, 5) == -1) {
 170                 DEBUG(0,("listen failed\n"));
 171         }
 172
 173         if (!resolve_name(desthost, &dest_ip, 0x20)) {
 174                 DEBUG(0,("Unable to resolve host %s\n", desthost));
 175                 exit(1);
 176         }
 177
 178         while (1) {
 179                 fd_set fds;
 180                 int num;
 181                 struct sockaddr addr;
 182                 int in_addrlen = sizeof(addr);
 183
 184                 FD_ZERO(&fds);
 185                 FD_SET(s, &fds);
 186
 187                 num = sys_select_intr(s+1,&fds,NULL);
 188                 if (num > 0) {
 189                         c = accept(s, &addr, &in_addrlen);
 190                         if (c != -1) {
 191                                 if (fork() == 0) {
 192                                         close(s);
 193                                         filter_child(c, dest_ip);
 194                                         exit(0);
 195                                 } else {
 196                                         close(c);
 197                                 }
 198                         }
 199                 }
 200         }
 201 }
 202
 203
 204 int main(int argc, char *argv[])
 205 {
 206         char *desthost;
 207         pstring configfile;
 208
 209         TimeInit();
 210
 211         setup_logging(argv[0],True);
 212
 213         charset_initialise();
 214
 215         pstrcpy(configfile,CONFIGFILE);
 216
 217         if (argc < 2) {
 218                 fprintf(stderr,"smbfilter <desthost> <netbiosname>\n");
 219                 exit(1);
 220         }
 221
 222         desthost = argv[1];
 223         if (argc > 2) {
 224                 netbiosname = argv[2];
 225         }
 226
 227         if (!lp_load(configfile,True,False,False)) {
 228                 DEBUG(0,("Unable to load config file\n"));
 229         }
 230
 231         start_filter(desthost);
 232         return 0;
 233 }