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 "libsmb/namequery.h"
  24 #include "../lib/util/select.h"
  25 #include "libsmb/nmblib.h"
  26 #include "lib/util/sys_rw_data.h"
  27
  28 #define SECURITY_MASK 0
  29 #define SECURITY_SET  0
  30
  31 /* this forces non-unicode */
  32 #define CAPABILITY_MASK 0
  33 #define CAPABILITY_SET  0
  34
  35 /* and non-unicode for the client too */
  36 #define CLI_CAPABILITY_MASK 0
  37 #define CLI_CAPABILITY_SET  0
  38
  39 static char *netbiosname;
  40
  41 static void save_file(const char *fname, void *ppacket, size_t length)
  42 {
  43         int fd;
  44         fd = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0644);
  45         if (fd == -1) {
  46                 perror(fname);
  47                 return;
  48         }
  49         if (write(fd, ppacket, length) != length) {
  50                 fprintf(stderr,"Failed to write %s\n", fname);
  51                 close(fd);
  52                 return;
  53         }
  54         close(fd);
  55         printf("Wrote %ld bytes to %s\n", (unsigned long)length, fname);
  56 }
  57
  58 static void filter_reply(char *buf)
  59 {
  60         int msg_type = CVAL(buf,0);
  61         int type = CVAL(buf,smb_com);
  62         unsigned x;
  63
  64         if (msg_type) return;
  65
  66         switch (type) {
  67
  68         case SMBnegprot:
  69                 /* force the security bits */
  70                 x = CVAL(buf, smb_vwv1);
  71                 x = (x | SECURITY_SET) & ~SECURITY_MASK;
  72                 SCVAL(buf, smb_vwv1, x);
  73
  74                 /* force the capabilities */
  75                 x = IVAL(buf,smb_vwv9+1);
  76                 x = (x | CAPABILITY_SET) & ~CAPABILITY_MASK;
  77                 SIVAL(buf, smb_vwv9+1, x);
  78                 break;
  79
  80         }
  81 }
  82
  83 static void filter_request(char *buf, size_t buf_len)
  84 {
  85         int msg_type = CVAL(buf,0);
  86         int type = CVAL(buf,smb_com);
  87         unsigned x;
  88         fstring name1,name2;
  89         int name_len1 = 0;
  90         int name_len2;
  91         int name_type1, name_type2;
  92         int ret;
  93
  94         if (msg_type) {
  95                 /* it's a netbios special */
  96                 switch (msg_type)
  97                 case 0x81:
  98                         /* session request */
  99                         /* inbuf_size is guaranteed to be at least 4. */
 100                         name_len1 = name_len((unsigned char *)(buf+4),
 101                                         buf_len - 4);
 102                         if (name_len1 <= 0 || name_len1 > buf_len - 4) {
 103                                 DEBUG(0,("Invalid name length in session request\n"));
 104                                 return;
 105                         }
 106                         name_len2 = name_len((unsigned char *)(buf+4+name_len1),
 107                                         buf_len - 4 - name_len1);
 108                         if (name_len2 <= 0 || name_len2 > buf_len - 4 - name_len1) {
 109                                 DEBUG(0,("Invalid name length in session request\n"));
 110                                 return;
 111                         }
 112
 113                         name_type1 = name_extract((unsigned char *)buf,
 114                                         buf_len,(unsigned int)4,name1);
 115                         name_type2 = name_extract((unsigned char *)buf,
 116                                         buf_len,(unsigned int)(4 + name_len1),name2);
 117
 118                         if (name_type1 == -1 || name_type2 == -1) {
 119                                 DEBUG(0,("Invalid name type in session request\n"));
 120                                 return;
 121                         }
 122
 123                         d_printf("session_request: %s -> %s\n",
 124                                  name1, name2);
 125                         if (netbiosname) {
 126                                 char *mangled = name_mangle(
 127                                         talloc_tos(), netbiosname, 0x20);
 128                                 if (mangled != NULL) {
 129                                         /* replace the destination netbios
 130                                          * name */
 131                                         memcpy(buf+4, mangled,
 132                                                name_len((unsigned char *)mangled,
 133                                                         talloc_get_size(mangled)));
 134                                         TALLOC_FREE(mangled);
 135                                 }
 136                         }
 137                 return;
 138         }
 139
 140         /* it's an ordinary SMB request */
 141         switch (type) {
 142         case SMBsesssetupX:
 143                 /* force the client capabilities */
 144                 x = IVAL(buf,smb_vwv11);
 145                 d_printf("SMBsesssetupX cap=0x%08x\n", x);
 146                 d_printf("pwlen=%d/%d\n", SVAL(buf, smb_vwv7), SVAL(buf, smb_vwv8));
 147                 ret = system("mv sessionsetup.dat sessionsetup1.dat");
 148                 if (ret == -1) {
 149                         DBG_ERR("failed to call mv command\n");
 150                 }
 151                 save_file("sessionsetup.dat", smb_buf(buf), SVAL(buf, smb_vwv7));
 152                 x = (x | CLI_CAPABILITY_SET) & ~CLI_CAPABILITY_MASK;
 153                 SIVAL(buf, smb_vwv11, x);
 154                 break;
 155         }
 156 }
 157
 158 /****************************************************************************
 159  Send an smb to a fd.
 160 ****************************************************************************/
 161
 162 static bool send_smb(int fd, char *buffer)
 163 {
 164         size_t len;
 165         size_t nwritten=0;
 166         ssize_t ret;
 167
 168         len = smb_len(buffer) + 4;
 169
 170         while (nwritten < len) {
 171                 ret = write_data(fd,buffer+nwritten,len - nwritten);
 172                 if (ret <= 0) {
 173                         DEBUG(0,("Error writing %d bytes to client. %d. (%s)\n",
 174                                 (int)len,(int)ret, strerror(errno) ));
 175                         return false;
 176                 }
 177                 nwritten += ret;
 178         }
 179
 180         return true;
 181 }
 182
 183 static void filter_child(int c, struct sockaddr_storage *dest_ss)
 184 {
 185         NTSTATUS status;
 186         int s = -1;
 187         char packet[128*1024];
 188
 189         /* we have a connection from a new client, now connect to the server */
 190         status = open_socket_out(dest_ss, TCP_SMB_PORT, LONG_CONNECT_TIMEOUT, &s);
 191         if (!NT_STATUS_IS_OK(status)) {
 192                 char addr[INET6_ADDRSTRLEN];
 193                 if (dest_ss) {
 194                         print_sockaddr(addr, sizeof(addr), dest_ss);
 195                 }
 196
 197                 d_printf("Unable to connect to %s (%s)\n",
 198                          dest_ss?addr:"NULL", nt_errstr(status));
 199                 exit(1);
 200         }
 201
 202         while (c != -1 || s != -1) {
 203                 struct pollfd fds[2];
 204                 int num_fds, ret;
 205
 206                 memset(fds, 0, sizeof(struct pollfd) * 2);
 207                 fds[0].fd = -1;
 208                 fds[1].fd = -1;
 209                 num_fds = 0;
 210
 211                 if (s != -1) {
 212                         fds[num_fds].fd = s;
 213                         fds[num_fds].events = POLLIN|POLLHUP;
 214                         num_fds += 1;
 215                 }
 216                 if (c != -1) {
 217                         fds[num_fds].fd = c;
 218                         fds[num_fds].events = POLLIN|POLLHUP;
 219                         num_fds += 1;
 220                 }
 221
 222                 ret = sys_poll_intr(fds, num_fds, -1);
 223                 if (ret <= 0) {
 224                         continue;
 225                 }
 226
 227                 /*
 228                  * find c in fds and see if it's readable
 229                  */
 230                 if ((c != -1) &&
 231                     (((fds[0].fd == c)
 232                       && (fds[0].revents & (POLLIN|POLLHUP|POLLERR))) ||
 233                      ((fds[1].fd == c)
 234                       && (fds[1].revents & (POLLIN|POLLHUP|POLLERR))))) {
 235                         size_t len;
 236                         if (!NT_STATUS_IS_OK(receive_smb_raw(
 237                                                         c, packet, sizeof(packet),
 238                                                         0, 0, &len))) {
 239                                 d_printf("client closed connection\n");
 240                                 exit(0);
 241                         }
 242                         filter_request(packet, len);
 243                         if (!send_smb(s, packet)) {
 244                                 d_printf("server is dead\n");
 245                                 exit(1);
 246                         }
 247                 }
 248
 249                 /*
 250                  * find s in fds and see if it's readable
 251                  */
 252                 if ((s != -1) &&
 253                     (((fds[0].fd == s)
 254                       && (fds[0].revents & (POLLIN|POLLHUP|POLLERR))) ||
 255                      ((fds[1].fd == s)
 256                       && (fds[1].revents & (POLLIN|POLLHUP|POLLERR))))) {
 257                         size_t len;
 258                         if (!NT_STATUS_IS_OK(receive_smb_raw(
 259                                                         s, packet, sizeof(packet),
 260                                                         0, 0, &len))) {
 261                                 d_printf("server closed connection\n");
 262                                 exit(0);
 263                         }
 264                         filter_reply(packet);
 265                         if (!send_smb(c, packet)) {
 266                                 d_printf("client is dead\n");
 267                                 exit(1);
 268                         }
 269                 }
 270         }
 271         d_printf("Connection closed\n");
 272         exit(0);
 273 }
 274
 275
 276 static void start_filter(char *desthost)
 277 {
 278         int s, c;
 279         struct sockaddr_storage dest_ss;
 280         struct sockaddr_storage my_ss;
 281
 282         CatchChild();
 283
 284         /* start listening on port 445 locally */
 285
 286         zero_sockaddr(&my_ss);
 287         s = open_socket_in(SOCK_STREAM, &my_ss, TCP_SMB_PORT, true);
 288
 289         if (s < 0) {
 290                 d_printf("bind failed: %s\n", strerror(-s));
 291                 exit(1);
 292         }
 293
 294         if (listen(s, 5) == -1) {
 295                 d_printf("listen failed\n");
 296         }
 297
 298         if (!resolve_name(desthost, &dest_ss, 0x20, false)) {
 299                 d_printf("Unable to resolve host %s\n", desthost);
 300                 exit(1);
 301         }
 302
 303         while (1) {
 304                 int num, revents;
 305                 struct sockaddr_storage ss;
 306                 socklen_t in_addrlen = sizeof(ss);
 307
 308                 num = poll_intr_one_fd(s, POLLIN|POLLHUP, -1, &revents);
 309                 if ((num > 0) && (revents & (POLLIN|POLLHUP|POLLERR))) {
 310                         c = accept(s, (struct sockaddr *)&ss, &in_addrlen);
 311                         if (c != -1) {
 312                                 smb_set_close_on_exec(c);
 313                                 if (fork() == 0) {
 314                                         close(s);
 315                                         filter_child(c, &dest_ss);
 316                                         exit(0);
 317                                 } else {
 318                                         close(c);
 319                                 }
 320                         }
 321                 }
 322         }
 323 }
 324
 325
 326 int main(int argc, char *argv[])
 327 {
 328         char *desthost;
 329         const char *configfile;
 330         TALLOC_CTX *frame = talloc_stackframe();
 331
 332         smb_init_locale();
 333
 334         setup_logging(argv[0], DEBUG_STDOUT);
 335
 336         configfile = get_dyn_CONFIGFILE();
 337
 338         if (argc < 2) {
 339                 fprintf(stderr,"smbfilter <desthost> <netbiosname>\n");
 340                 exit(1);
 341         }
 342
 343         desthost = argv[1];
 344         if (argc > 2) {
 345                 netbiosname = argv[2];
 346         }
 347
 348         if (!lp_load_global(configfile)) {
 349                 d_printf("Unable to load config file\n");
 350         }
 351
 352         start_filter(desthost);
 353         gfree_all();
 354         TALLOC_FREE(frame);
 355         return 0;
 356 }