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         fstring 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  Send an smb to a fd.
 119 ****************************************************************************/
 120
 121 static bool send_smb(int fd, char *buffer)
 122 {
 123         size_t len;
 124         size_t nwritten=0;
 125         ssize_t ret;
 126
 127         len = smb_len(buffer) + 4;
 128
 129         while (nwritten < len) {
 130                 ret = write_data(fd,buffer+nwritten,len - nwritten);
 131                 if (ret <= 0) {
 132                         DEBUG(0,("Error writing %d bytes to client. %d. (%s)\n",
 133                                 (int)len,(int)ret, strerror(errno) ));
 134                         return false;
 135                 }
 136                 nwritten += ret;
 137         }
 138
 139         return true;
 140 }
 141
 142 static void filter_child(int c, struct sockaddr_storage *dest_ss)
 143 {
 144         int s;
 145
 146         /* we have a connection from a new client, now connect to the server */
 147         s = open_socket_out(SOCK_STREAM, dest_ss, 445, LONG_CONNECT_TIMEOUT);
 148
 149         if (s == -1) {
 150                 char addr[INET6_ADDRSTRLEN];
 151                 if (dest_ss) {
 152                         print_sockaddr(addr, sizeof(addr), dest_ss);
 153                 }
 154
 155                 d_printf("Unable to connect to %s (%s)\n",
 156                          dest_ss?addr:"NULL",strerror(errno));
 157                 exit(1);
 158         }
 159
 160         while (c != -1 || s != -1) {
 161                 fd_set fds;
 162                 int num;
 163
 164                 FD_ZERO(&fds);
 165                 if (s != -1) FD_SET(s, &fds);
 166                 if (c != -1) FD_SET(c, &fds);
 167
 168                 num = sys_select_intr(MAX(s+1, c+1),&fds,NULL,NULL,NULL);
 169                 if (num <= 0) continue;
 170
 171                 if (c != -1 && FD_ISSET(c, &fds)) {
 172                         size_t len;
 173                         if (!NT_STATUS_IS_OK(receive_smb_raw(
 174                                                      c, packet, 0, 0, &len))) {
 175                                 d_printf("client closed connection\n");
 176                                 exit(0);
 177                         }
 178                         filter_request(packet);
 179                         if (!send_smb(s, packet)) {
 180                                 d_printf("server is dead\n");
 181                                 exit(1);
 182                         }
 183                 }
 184                 if (s != -1 && FD_ISSET(s, &fds)) {
 185                         size_t len;
 186                         if (!NT_STATUS_IS_OK(receive_smb_raw(
 187                                                      s, packet, 0, 0, &len))) {
 188                                 d_printf("server closed connection\n");
 189                                 exit(0);
 190                         }
 191                         filter_reply(packet);
 192                         if (!send_smb(c, packet)) {
 193                                 d_printf("client is dead\n");
 194                                 exit(1);
 195                         }
 196                 }
 197         }
 198         d_printf("Connection closed\n");
 199         exit(0);
 200 }
 201
 202
 203 static void start_filter(char *desthost)
 204 {
 205         int s, c;
 206         struct sockaddr_storage dest_ss;
 207         struct sockaddr_storage my_ss;
 208
 209         CatchChild();
 210
 211         /* start listening on port 445 locally */
 212
 213         zero_addr(&my_ss);
 214         s = open_socket_in(SOCK_STREAM, 445, 0, &my_ss, True);
 215
 216         if (s == -1) {
 217                 d_printf("bind failed\n");
 218                 exit(1);
 219         }
 220
 221         if (listen(s, 5) == -1) {
 222                 d_printf("listen failed\n");
 223         }
 224
 225         if (!resolve_name(desthost, &dest_ss, 0x20)) {
 226                 d_printf("Unable to resolve host %s\n", desthost);
 227                 exit(1);
 228         }
 229
 230         while (1) {
 231                 fd_set fds;
 232                 int num;
 233                 struct sockaddr_storage ss;
 234                 socklen_t in_addrlen = sizeof(ss);
 235
 236                 FD_ZERO(&fds);
 237                 FD_SET(s, &fds);
 238
 239                 num = sys_select_intr(s+1,&fds,NULL,NULL,NULL);
 240                 if (num > 0) {
 241                         c = accept(s, (struct sockaddr *)&ss, &in_addrlen);
 242                         if (c != -1) {
 243                                 if (fork() == 0) {
 244                                         close(s);
 245                                         filter_child(c, &dest_ss);
 246                                         exit(0);
 247                                 } else {
 248                                         close(c);
 249                                 }
 250                         }
 251                 }
 252         }
 253 }
 254
 255
 256 int main(int argc, char *argv[])
 257 {
 258         char *desthost;
 259         const char *configfile;
 260         TALLOC_CTX *frame = talloc_stackframe();
 261
 262         load_case_tables();
 263
 264         setup_logging(argv[0],True);
 265
 266         configfile = get_dyn_CONFIGFILE();
 267
 268         if (argc < 2) {
 269                 fprintf(stderr,"smbfilter <desthost> <netbiosname>\n");
 270                 exit(1);
 271         }
 272
 273         desthost = argv[1];
 274         if (argc > 2) {
 275                 netbiosname = argv[2];
 276         }
 277
 278         if (!lp_load(configfile,True,False,False,True)) {
 279                 d_printf("Unable to load config file\n");
 280         }
 281
 282         start_filter(desthost);
 283         TALLOC_FREE(frame);
 284         return 0;
 285 }