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