source3/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, size_t buf_len)
  78 {
  79         int msg_type = CVAL(buf,0);
  80         int type = CVAL(buf,smb_com);
  81         unsigned x;
  82         fstring name1,name2;
  83         int name_len1, name_len2;
  84         int name_type1, name_type2;
  85
  86         if (msg_type) {
  87                 /* it's a netbios special */
  88                 switch (msg_type)
  89                 case 0x81:
  90                         /* session request */
  91                         /* inbuf_size is guaranteed to be at least 4. */
  92                         name_len1 = name_len((unsigned char *)(buf+4),
  93                                         buf_len - 4);
  94                         if (name_len1 <= 0 || name_len1 > buf_len - 4) {
  95                                 DEBUG(0,("Invalid name length in session request\n"));
  96                                 return;
  97                         }
  98                         name_len2 = name_len((unsigned char *)(buf+4+name_len1),
  99                                         buf_len - 4 - name_len1);
 100                         if (name_len2 <= 0 || name_len2 > buf_len - 4 - name_len1) {
 101                                 DEBUG(0,("Invalid name length in session request\n"));
 102                                 return;
 103                         }
 104
 105                         name_type1 = name_extract((unsigned char *)buf,
 106                                         buf_len,(unsigned int)4,name1);
 107                         name_type2 = name_extract((unsigned char *)buf,
 108                                         buf_len,(unsigned int)(4 + name_len1),name2);
 109
 110                         if (name_type1 == -1 || name_type2 == -1) {
 111                                 DEBUG(0,("Invalid name type in session request\n"));
 112                                 return;
 113                         }
 114
 115                         d_printf("sesion_request: %s -> %s\n",
 116                                  name1, name2);
 117                         if (netbiosname) {
 118                                 char *mangled = name_mangle(
 119                                         talloc_tos(), netbiosname, 0x20);
 120                                 if (mangled != NULL) {
 121                                         /* replace the destination netbios
 122                                          * name */
 123                                         memcpy(buf+4, mangled,
 124                                                name_len((unsigned char *)mangled,
 125                                                         talloc_get_size(mangled)));
 126                                         TALLOC_FREE(mangled);
 127                                 }
 128                         }
 129                 return;
 130         }
 131
 132         /* it's an ordinary SMB request */
 133         switch (type) {
 134         case SMBsesssetupX:
 135                 /* force the client capabilities */
 136                 x = IVAL(buf,smb_vwv11);
 137                 d_printf("SMBsesssetupX cap=0x%08x\n", x);
 138                 d_printf("pwlen=%d/%d\n", SVAL(buf, smb_vwv7), SVAL(buf, smb_vwv8));
 139                 system("mv sessionsetup.dat sessionsetup1.dat");
 140                 save_file("sessionsetup.dat", smb_buf(buf), SVAL(buf, smb_vwv7));
 141                 x = (x | CLI_CAPABILITY_SET) & ~CLI_CAPABILITY_MASK;
 142                 SIVAL(buf, smb_vwv11, x);
 143                 break;
 144         }
 145 }
 146
 147 /****************************************************************************
 148  Send an smb to a fd.
 149 ****************************************************************************/
 150
 151 static bool send_smb(int fd, char *buffer)
 152 {
 153         size_t len;
 154         size_t nwritten=0;
 155         ssize_t ret;
 156
 157         len = smb_len(buffer) + 4;
 158
 159         while (nwritten < len) {
 160                 ret = write_data(fd,buffer+nwritten,len - nwritten);
 161                 if (ret <= 0) {
 162                         DEBUG(0,("Error writing %d bytes to client. %d. (%s)\n",
 163                                 (int)len,(int)ret, strerror(errno) ));
 164                         return false;
 165                 }
 166                 nwritten += ret;
 167         }
 168
 169         return true;
 170 }
 171
 172 static void filter_child(int c, struct sockaddr_storage *dest_ss)
 173 {
 174         NTSTATUS status;
 175         int s = -1;
 176
 177         /* we have a connection from a new client, now connect to the server */
 178         status = open_socket_out(dest_ss, 445, LONG_CONNECT_TIMEOUT, &s);
 179
 180         if (s == -1) {
 181                 char addr[INET6_ADDRSTRLEN];
 182                 if (dest_ss) {
 183                         print_sockaddr(addr, sizeof(addr), dest_ss);
 184                 }
 185
 186                 d_printf("Unable to connect to %s (%s)\n",
 187                          dest_ss?addr:"NULL",strerror(errno));
 188                 exit(1);
 189         }
 190
 191         while (c != -1 || s != -1) {
 192                 fd_set fds;
 193                 int num;
 194
 195                 FD_ZERO(&fds);
 196                 if (s >= 0 && s < FD_SETSIZE) FD_SET(s, &fds);
 197                 if (c >= 0 && c < FD_SETSIZE) FD_SET(c, &fds);
 198
 199                 num = sys_select_intr(MAX(s+1, c+1),&fds,NULL,NULL,NULL);
 200                 if (num <= 0) continue;
 201
 202                 if (c != -1 && FD_ISSET(c, &fds)) {
 203                         size_t len;
 204                         if (!NT_STATUS_IS_OK(receive_smb_raw(
 205                                                         c, packet, sizeof(packet),
 206                                                         0, 0, &len))) {
 207                                 d_printf("client closed connection\n");
 208                                 exit(0);
 209                         }
 210                         filter_request(packet, len);
 211                         if (!send_smb(s, packet)) {
 212                                 d_printf("server is dead\n");
 213                                 exit(1);
 214                         }
 215                 }
 216                 if (s != -1 && FD_ISSET(s, &fds)) {
 217                         size_t len;
 218                         if (!NT_STATUS_IS_OK(receive_smb_raw(
 219                                                         s, packet, sizeof(packet),
 220                                                         0, 0, &len))) {
 221                                 d_printf("server closed connection\n");
 222                                 exit(0);
 223                         }
 224                         filter_reply(packet);
 225                         if (!send_smb(c, packet)) {
 226                                 d_printf("client is dead\n");
 227                                 exit(1);
 228                         }
 229                 }
 230         }
 231         d_printf("Connection closed\n");
 232         exit(0);
 233 }
 234
 235
 236 static void start_filter(char *desthost)
 237 {
 238         int s, c;
 239         struct sockaddr_storage dest_ss;
 240         struct sockaddr_storage my_ss;
 241
 242         CatchChild();
 243
 244         /* start listening on port 445 locally */
 245
 246         zero_sockaddr(&my_ss);
 247         s = open_socket_in(SOCK_STREAM, 445, 0, &my_ss, True);
 248
 249         if (s == -1) {
 250                 d_printf("bind failed\n");
 251                 exit(1);
 252         }
 253
 254         if (listen(s, 5) == -1) {
 255                 d_printf("listen failed\n");
 256         }
 257
 258         if (!resolve_name(desthost, &dest_ss, 0x20, false)) {
 259                 d_printf("Unable to resolve host %s\n", desthost);
 260                 exit(1);
 261         }
 262
 263         while (1) {
 264                 fd_set fds;
 265                 int num;
 266                 struct sockaddr_storage ss;
 267                 socklen_t in_addrlen = sizeof(ss);
 268
 269                 FD_ZERO(&fds);
 270                 if (s < 0 || s >= FD_SETSIZE) {
 271                         break;
 272                 }
 273                 FD_SET(s, &fds);
 274
 275                 num = sys_select_intr(s+1,&fds,NULL,NULL,NULL);
 276                 if (num > 0) {
 277                         c = accept(s, (struct sockaddr *)&ss, &in_addrlen);
 278                         if (c != -1) {
 279                                 if (fork() == 0) {
 280                                         close(s);
 281                                         filter_child(c, &dest_ss);
 282                                         exit(0);
 283                                 } else {
 284                                         close(c);
 285                                 }
 286                         }
 287                 }
 288         }
 289 }
 290
 291
 292 int main(int argc, char *argv[])
 293 {
 294         char *desthost;
 295         const char *configfile;
 296         TALLOC_CTX *frame = talloc_stackframe();
 297
 298         load_case_tables();
 299
 300         setup_logging(argv[0],True);
 301
 302         configfile = get_dyn_CONFIGFILE();
 303
 304         if (argc < 2) {
 305                 fprintf(stderr,"smbfilter <desthost> <netbiosname>\n");
 306                 exit(1);
 307         }
 308
 309         desthost = argv[1];
 310         if (argc > 2) {
 311                 netbiosname = argv[2];
 312         }
 313
 314         if (!lp_load(configfile,True,False,False,True)) {
 315                 d_printf("Unable to load config file\n");
 316         }
 317
 318         start_filter(desthost);
 319         TALLOC_FREE(frame);
 320         return 0;
 321 }