source/utils/smbfilter.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    SMB filter/socket plugin
   4    Copyright (C) Andrew Tridgell 1999
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #include "includes.h"
  21
  22 #define SECURITY_MASK 0
  23 #define SECURITY_SET  0
  24
  25 /* this forces non-unicode */
  26 #define CAPABILITY_MASK 0
  27 #define CAPABILITY_SET  0
  28
  29 /* and non-unicode for the client too */
  30 #define CLI_CAPABILITY_MASK 0
  31 #define CLI_CAPABILITY_SET  0
  32
  33 static char *netbiosname;
  34 static char packet[BUFFER_SIZE];
  35
  36 static void save_file(const char *fname, void *ppacket, size_t length)
  37 {
  38         int fd;
  39         fd = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0644);
  40         if (fd == -1) {
  41                 perror(fname);
  42                 return;
  43         }
  44         if (write(fd, ppacket, length) != length) {
  45                 fprintf(stderr,"Failed to write %s\n", fname);
  46                 return;
  47         }
  48         close(fd);
  49         printf("Wrote %ld bytes to %s\n", (unsigned long)length, fname);
  50 }
  51
  52 static void filter_reply(char *buf)
  53 {
  54         int msg_type = CVAL(buf,0);
  55         int type = CVAL(buf,smb_com);
  56         unsigned x;
  57
  58         if (msg_type) return;
  59
  60         switch (type) {
  61
  62         case SMBnegprot:
  63                 /* force the security bits */
  64                 x = CVAL(buf, smb_vwv1);
  65                 x = (x | SECURITY_SET) & ~SECURITY_MASK;
  66                 SCVAL(buf, smb_vwv1, x);
  67
  68                 /* force the capabilities */
  69                 x = IVAL(buf,smb_vwv9+1);
  70                 x = (x | CAPABILITY_SET) & ~CAPABILITY_MASK;
  71                 SIVAL(buf, smb_vwv9+1, x);
  72                 break;
  73
  74         }
  75 }
  76
  77 static void filter_request(char *buf)
  78 {
  79         int msg_type = CVAL(buf,0);
  80         int type = CVAL(buf,smb_com);
  81         pstring name1,name2;
  82         unsigned x;
  83
  84         if (msg_type) {
  85                 /* it's a netbios special */
  86                 switch (msg_type) {
  87                 case 0x81:
  88                         /* session request */
  89                         name_extract(buf,4,name1);
  90                         name_extract(buf,4 + name_len(buf + 4),name2);
  91                         d_printf("sesion_request: %s -> %s\n",
  92                                  name1, name2);
  93                         if (netbiosname) {
  94                                 /* replace the destination netbios name */
  95                                 name_mangle(netbiosname, buf+4, 0x20);
  96                         }
  97                 }
  98                 return;
  99         }
 100
 101         /* it's an ordinary SMB request */
 102         switch (type) {
 103         case SMBsesssetupX:
 104                 /* force the client capabilities */
 105                 x = IVAL(buf,smb_vwv11);
 106                 d_printf("SMBsesssetupX cap=0x%08x\n", x);
 107                 d_printf("pwlen=%d/%d\n", SVAL(buf, smb_vwv7), SVAL(buf, smb_vwv8));
 108                 system("mv sessionsetup.dat sessionsetup1.dat");
 109                 save_file("sessionsetup.dat", smb_buf(buf), SVAL(buf, smb_vwv7));
 110                 x = (x | CLI_CAPABILITY_SET) & ~CLI_CAPABILITY_MASK;
 111                 SIVAL(buf, smb_vwv11, x);
 112                 break;
 113         }
 114
 115 }
 116
 117
 118 static void filter_child(int c, struct in_addr dest_ip)
 119 {
 120         int s;
 121
 122         /* we have a connection from a new client, now connect to the server */
 123         s = open_socket_out(SOCK_STREAM, &dest_ip, 445, LONG_CONNECT_TIMEOUT);
 124
 125         if (s == -1) {
 126                 d_printf("Unable to connect to %s\n", inet_ntoa(dest_ip));
 127                 exit(1);
 128         }
 129
 130         while (c != -1 || s != -1) {
 131                 fd_set fds;
 132                 int num;
 133
 134                 FD_ZERO(&fds);
 135                 if (s != -1) FD_SET(s, &fds);
 136                 if (c != -1) FD_SET(c, &fds);
 137
 138                 num = sys_select_intr(MAX(s+1, c+1),&fds,NULL,NULL,NULL);
 139                 if (num <= 0) continue;
 140
 141                 if (c != -1 && FD_ISSET(c, &fds)) {
 142                         if (!receive_smb(c, packet, 0)) {
 143                                 d_printf("client closed connection\n");
 144                                 exit(0);
 145                         }
 146                         filter_request(packet);
 147                         if (!send_smb(s, packet)) {
 148                                 d_printf("server is dead\n");
 149                                 exit(1);
 150                         }
 151                 }
 152                 if (s != -1 && FD_ISSET(s, &fds)) {
 153                         if (!receive_smb(s, packet, 0)) {
 154                                 d_printf("server closed connection\n");
 155                                 exit(0);
 156                         }
 157                         filter_reply(packet);
 158                         if (!send_smb(c, packet)) {
 159                                 d_printf("client is dead\n");
 160                                 exit(1);
 161                         }
 162                 }
 163         }
 164         d_printf("Connection closed\n");
 165         exit(0);
 166 }
 167
 168
 169 static void start_filter(char *desthost)
 170 {
 171         int s, c;
 172         struct in_addr dest_ip;
 173
 174         CatchChild();
 175
 176         /* start listening on port 445 locally */
 177         s = open_socket_in(SOCK_STREAM, 445, 0, 0, True);
 178
 179         if (s == -1) {
 180                 d_printf("bind failed\n");
 181                 exit(1);
 182         }
 183
 184         if (listen(s, 5) == -1) {
 185                 d_printf("listen failed\n");
 186         }
 187
 188         if (!resolve_name(desthost, &dest_ip, 0x20)) {
 189                 d_printf("Unable to resolve host %s\n", desthost);
 190                 exit(1);
 191         }
 192
 193         while (1) {
 194                 fd_set fds;
 195                 int num;
 196                 struct sockaddr addr;
 197                 socklen_t in_addrlen = sizeof(addr);
 198
 199                 FD_ZERO(&fds);
 200                 FD_SET(s, &fds);
 201
 202                 num = sys_select_intr(s+1,&fds,NULL,NULL,NULL);
 203                 if (num > 0) {
 204                         c = accept(s, &addr, &in_addrlen);
 205                         if (c != -1) {
 206                                 if (fork() == 0) {
 207                                         close(s);
 208                                         filter_child(c, dest_ip);
 209                                         exit(0);
 210                                 } else {
 211                                         close(c);
 212                                 }
 213                         }
 214                 }
 215         }
 216 }
 217
 218
 219 int main(int argc, char *argv[])
 220 {
 221         char *desthost;
 222         pstring configfile;
 223
 224         setup_logging(argv[0],True);
 225
 226         pstrcpy(configfile,dyn_CONFIGFILE);
 227
 228         if (argc < 2) {
 229                 fprintf(stderr,"smbfilter <desthost> <netbiosname>\n");
 230                 exit(1);
 231         }
 232
 233         desthost = argv[1];
 234         if (argc > 2) {
 235                 netbiosname = argv[2];
 236         }
 237
 238         if (!lp_load(configfile,True,False,False,True)) {
 239                 d_printf("Unable to load config file\n");
 240         }
 241
 242         start_filter(desthost);
 243         return 0;
 244 }