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 #include "system/filesys.h"
  22 #include "system/select.h"
  23 #include "../lib/util/select.h"
  24 #include "libsmb/nmblib.h"
  25 #include "lib/util/sys_rw_data.h"
  26
  27 #define SECURITY_MASK 0
  28 #define SECURITY_SET  0
  29
  30 /* this forces non-unicode */
  31 #define CAPABILITY_MASK 0
  32 #define CAPABILITY_SET  0
  33
  34 /* and non-unicode for the client too */
  35 #define CLI_CAPABILITY_MASK 0
  36 #define CLI_CAPABILITY_SET  0
  37
  38 static char *netbiosname;
  39
  40 static void save_file(const char *fname, void *ppacket, size_t length)
  41 {
  42         int fd;
  43         fd = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0644);
  44         if (fd == -1) {
  45                 perror(fname);
  46                 return;
  47         }
  48         if (write(fd, ppacket, length) != length) {
  49                 fprintf(stderr,"Failed to write %s\n", fname);
  50                 close(fd);
  51                 return;
  52         }
  53         close(fd);
  54         printf("Wrote %ld bytes to %s\n", (unsigned long)length, fname);
  55 }
  56
  57 static void filter_reply(char *buf)
  58 {
  59         int msg_type = CVAL(buf,0);
  60         int type = CVAL(buf,smb_com);
  61         unsigned x;
  62
  63         if (msg_type) return;
  64
  65         switch (type) {
  66
  67         case SMBnegprot:
  68                 /* force the security bits */
  69                 x = CVAL(buf, smb_vwv1);
  70                 x = (x | SECURITY_SET) & ~SECURITY_MASK;
  71                 SCVAL(buf, smb_vwv1, x);
  72
  73                 /* force the capabilities */
  74                 x = IVAL(buf,smb_vwv9+1);
  75                 x = (x | CAPABILITY_SET) & ~CAPABILITY_MASK;
  76                 SIVAL(buf, smb_vwv9+1, x);
  77                 break;
  78
  79         }
  80 }
  81
  82 static void filter_request(char *buf, size_t buf_len)
  83 {
  84         int msg_type = CVAL(buf,0);
  85         int type = CVAL(buf,smb_com);
  86         unsigned x;
  87         fstring name1,name2;
  88         int name_len1 = 0;
  89         int name_len2;
  90         int name_type1, name_type2;
  91         int ret;
  92
  93         if (msg_type) {
  94                 /* it's a netbios special */
  95                 switch (msg_type)
  96                 case 0x81:
  97                         /* session request */
  98                         /* inbuf_size is guaranteed to be at least 4. */
  99                         name_len1 = name_len((unsigned char *)(buf+4),
 100                                         buf_len - 4);
 101                         if (name_len1 <= 0 || name_len1 > buf_len - 4) {
 102                                 DEBUG(0,("Invalid name length in session request\n"));
 103                                 return;
 104                         }
 105                         name_len2 = name_len((unsigned char *)(buf+4+name_len1),
 106                                         buf_len - 4 - name_len1);
 107                         if (name_len2 <= 0 || name_len2 > buf_len - 4 - name_len1) {
 108                                 DEBUG(0,("Invalid name length in session request\n"));
 109                                 return;
 110                         }
 111
 112                         name_type1 = name_extract((unsigned char *)buf,
 113                                         buf_len,(unsigned int)4,name1);
 114                         name_type2 = name_extract((unsigned char *)buf,
 115                                         buf_len,(unsigned int)(4 + name_len1),name2);
 116
 117                         if (name_type1 == -1 || name_type2 == -1) {
 118                                 DEBUG(0,("Invalid name type in session request\n"));
 119                                 return;
 120                         }
 121
 122                         d_printf("sesion_request: %s -> %s\n",
 123                                  name1, name2);
 124                         if (netbiosname) {
 125                                 char *mangled = name_mangle(
 126                                         talloc_tos(), netbiosname, 0x20);
 127                                 if (mangled != NULL) {
 128                                         /* replace the destination netbios
 129                                          * name */
 130                                         memcpy(buf+4, mangled,
 131                                                name_len((unsigned char *)mangled,
 132                                                         talloc_get_size(mangled)));
 133                                         TALLOC_FREE(mangled);
 134                                 }
 135                         }
 136                 return;
 137         }
 138
 139         /* it's an ordinary SMB request */
 140         switch (type) {
 141         case SMBsesssetupX:
 142                 /* force the client capabilities */
 143                 x = IVAL(buf,smb_vwv11);
 144                 d_printf("SMBsesssetupX cap=0x%08x\n", x);
 145                 d_printf("pwlen=%d/%d\n", SVAL(buf, smb_vwv7), SVAL(buf, smb_vwv8));
 146                 ret = system("mv sessionsetup.dat sessionsetup1.dat");
 147                 if (ret == -1) {
 148                         DBG_ERR("failed to call mv command\n");
 149                 }
 150                 save_file("sessionsetup.dat", smb_buf(buf), SVAL(buf, smb_vwv7));
 151                 x = (x | CLI_CAPABILITY_SET) & ~CLI_CAPABILITY_MASK;
 152                 SIVAL(buf, smb_vwv11, x);
 153                 break;
 154         }
 155 }
 156
 157 /****************************************************************************
 158  Send an smb to a fd.
 159 ****************************************************************************/
 160
 161 static bool send_smb(int fd, char *buffer)
 162 {
 163         size_t len;
 164         size_t nwritten=0;
 165         ssize_t ret;
 166
 167         len = smb_len(buffer) + 4;
 168
 169         while (nwritten < len) {
 170                 ret = write_data(fd,buffer+nwritten,len - nwritten);
 171                 if (ret <= 0) {
 172                         DEBUG(0,("Error writing %d bytes to client. %d. (%s)\n",
 173                                 (int)len,(int)ret, strerror(errno) ));
 174                         return false;
 175                 }
 176                 nwritten += ret;
 177         }
 178
 179         return true;
 180 }
 181
 182 static void filter_child(int c, struct sockaddr_storage *dest_ss)
 183 {
 184         NTSTATUS status;
 185         int s = -1;
 186         char packet[128*1024];
 187
 188         /* we have a connection from a new client, now connect to the server */
 189         status = open_socket_out(dest_ss, TCP_SMB_PORT, LONG_CONNECT_TIMEOUT, &s);
 190         if (!NT_STATUS_IS_OK(status)) {
 191                 char addr[INET6_ADDRSTRLEN];
 192                 if (dest_ss) {
 193                         print_sockaddr(addr, sizeof(addr), dest_ss);
 194                 }
 195
 196                 d_printf("Unable to connect to %s (%s)\n",
 197                          dest_ss?addr:"NULL", nt_errstr(status));
 198                 exit(1);
 199         }
 200
 201         while (c != -1 || s != -1) {
 202                 struct pollfd fds[2];
 203                 int num_fds, ret;
 204
 205                 memset(fds, 0, sizeof(struct pollfd) * 2);
 206                 fds[0].fd = -1;
 207                 fds[1].fd = -1;
 208                 num_fds = 0;
 209
 210                 if (s != -1) {
 211                         fds[num_fds].fd = s;
 212                         fds[num_fds].events = POLLIN|POLLHUP;
 213                         num_fds += 1;
 214                 }
 215                 if (c != -1) {
 216                         fds[num_fds].fd = c;
 217                         fds[num_fds].events = POLLIN|POLLHUP;
 218                         num_fds += 1;
 219                 }
 220
 221                 ret = sys_poll_intr(fds, num_fds, -1);
 222                 if (ret <= 0) {
 223                         continue;
 224                 }
 225
 226                 /*
 227                  * find c in fds and see if it's readable
 228                  */
 229                 if ((c != -1) &&
 230                     (((fds[0].fd == c)
 231                       && (fds[0].revents & (POLLIN|POLLHUP|POLLERR))) ||
 232                      ((fds[1].fd == c)
 233                       && (fds[1].revents & (POLLIN|POLLHUP|POLLERR))))) {
 234                         size_t len;
 235                         if (!NT_STATUS_IS_OK(receive_smb_raw(
 236                                                         c, packet, sizeof(packet),
 237                                                         0, 0, &len))) {
 238                                 d_printf("client closed connection\n");
 239                                 exit(0);
 240                         }
 241                         filter_request(packet, len);
 242                         if (!send_smb(s, packet)) {
 243                                 d_printf("server is dead\n");
 244                                 exit(1);
 245                         }
 246                 }
 247
 248                 /*
 249                  * find s in fds and see if it's readable
 250                  */
 251                 if ((s != -1) &&
 252                     (((fds[0].fd == s)
 253                       && (fds[0].revents & (POLLIN|POLLHUP|POLLERR))) ||
 254                      ((fds[1].fd == s)
 255                       && (fds[1].revents & (POLLIN|POLLHUP|POLLERR))))) {
 256                         size_t len;
 257                         if (!NT_STATUS_IS_OK(receive_smb_raw(
 258                                                         s, packet, sizeof(packet),
 259                                                         0, 0, &len))) {
 260                                 d_printf("server closed connection\n");
 261                                 exit(0);
 262                         }
 263                         filter_reply(packet);
 264                         if (!send_smb(c, packet)) {
 265                                 d_printf("client is dead\n");
 266                                 exit(1);
 267                         }
 268                 }
 269         }
 270         d_printf("Connection closed\n");
 271         exit(0);
 272 }
 273
 274
 275 static void start_filter(char *desthost)
 276 {
 277         int s, c;
 278         struct sockaddr_storage dest_ss;
 279         struct sockaddr_storage my_ss;
 280
 281         CatchChild();
 282
 283         /* start listening on port 445 locally */
 284
 285         zero_sockaddr(&my_ss);
 286         s = open_socket_in(SOCK_STREAM, TCP_SMB_PORT, 0, &my_ss, True);
 287
 288         if (s == -1) {
 289                 d_printf("bind failed\n");
 290                 exit(1);
 291         }
 292
 293         if (listen(s, 5) == -1) {
 294                 d_printf("listen failed\n");
 295         }
 296
 297         if (!resolve_name(desthost, &dest_ss, 0x20, false)) {
 298                 d_printf("Unable to resolve host %s\n", desthost);
 299                 exit(1);
 300         }
 301
 302         while (1) {
 303                 int num, revents;
 304                 struct sockaddr_storage ss;
 305                 socklen_t in_addrlen = sizeof(ss);
 306
 307                 num = poll_intr_one_fd(s, POLLIN|POLLHUP, -1, &revents);
 308                 if ((num > 0) && (revents & (POLLIN|POLLHUP|POLLERR))) {
 309                         c = accept(s, (struct sockaddr *)&ss, &in_addrlen);
 310                         if (c != -1) {
 311                                 smb_set_close_on_exec(c);
 312                                 if (fork() == 0) {
 313                                         close(s);
 314                                         filter_child(c, &dest_ss);
 315                                         exit(0);
 316                                 } else {
 317                                         close(c);
 318                                 }
 319                         }
 320                 }
 321         }
 322 }
 323
 324
 325 int main(int argc, char *argv[])
 326 {
 327         char *desthost;
 328         const char *configfile;
 329         TALLOC_CTX *frame = talloc_stackframe();
 330
 331         smb_init_locale();
 332
 333         setup_logging(argv[0], DEBUG_STDOUT);
 334
 335         configfile = get_dyn_CONFIGFILE();
 336
 337         if (argc < 2) {
 338                 fprintf(stderr,"smbfilter <desthost> <netbiosname>\n");
 339                 exit(1);
 340         }
 341
 342         desthost = argv[1];
 343         if (argc > 2) {
 344                 netbiosname = argv[2];
 345         }
 346
 347         if (!lp_load_global(configfile)) {
 348                 d_printf("Unable to load config file\n");
 349         }
 350
 351         start_filter(desthost);
 352         TALLOC_FREE(frame);
 353         return 0;
 354 }