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 static char packet[BUFFER_SIZE];
  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, name_len2;
  89         int name_type1, name_type2;
  90
  91         if (msg_type) {
  92                 /* it's a netbios special */
  93                 switch (msg_type)
  94                 case 0x81:
  95                         /* session request */
  96                         /* inbuf_size is guaranteed to be at least 4. */
  97                         name_len1 = name_len((unsigned char *)(buf+4),
  98                                         buf_len - 4);
  99                         if (name_len1 <= 0 || name_len1 > buf_len - 4) {
 100                                 DEBUG(0,("Invalid name length in session request\n"));
 101                                 return;
 102                         }
 103                         name_len2 = name_len((unsigned char *)(buf+4+name_len1),
 104                                         buf_len - 4 - name_len1);
 105                         if (name_len2 <= 0 || name_len2 > buf_len - 4 - name_len1) {
 106                                 DEBUG(0,("Invalid name length in session request\n"));
 107                                 return;
 108                         }
 109
 110                         name_type1 = name_extract((unsigned char *)buf,
 111                                         buf_len,(unsigned int)4,name1);
 112                         name_type2 = name_extract((unsigned char *)buf,
 113                                         buf_len,(unsigned int)(4 + name_len1),name2);
 114
 115                         if (name_type1 == -1 || name_type2 == -1) {
 116                                 DEBUG(0,("Invalid name type in session request\n"));
 117                                 return;
 118                         }
 119
 120                         d_printf("sesion_request: %s -> %s\n",
 121                                  name1, name2);
 122                         if (netbiosname) {
 123                                 char *mangled = name_mangle(
 124                                         talloc_tos(), netbiosname, 0x20);
 125                                 if (mangled != NULL) {
 126                                         /* replace the destination netbios
 127                                          * name */
 128                                         memcpy(buf+4, mangled,
 129                                                name_len((unsigned char *)mangled,
 130                                                         talloc_get_size(mangled)));
 131                                         TALLOC_FREE(mangled);
 132                                 }
 133                         }
 134                 return;
 135         }
 136
 137         /* it's an ordinary SMB request */
 138         switch (type) {
 139         case SMBsesssetupX:
 140                 /* force the client capabilities */
 141                 x = IVAL(buf,smb_vwv11);
 142                 d_printf("SMBsesssetupX cap=0x%08x\n", x);
 143                 d_printf("pwlen=%d/%d\n", SVAL(buf, smb_vwv7), SVAL(buf, smb_vwv8));
 144                 system("mv sessionsetup.dat sessionsetup1.dat");
 145                 save_file("sessionsetup.dat", smb_buf(buf), SVAL(buf, smb_vwv7));
 146                 x = (x | CLI_CAPABILITY_SET) & ~CLI_CAPABILITY_MASK;
 147                 SIVAL(buf, smb_vwv11, x);
 148                 break;
 149         }
 150 }
 151
 152 /****************************************************************************
 153  Send an smb to a fd.
 154 ****************************************************************************/
 155
 156 static bool send_smb(int fd, char *buffer)
 157 {
 158         size_t len;
 159         size_t nwritten=0;
 160         ssize_t ret;
 161
 162         len = smb_len(buffer) + 4;
 163
 164         while (nwritten < len) {
 165                 ret = write_data(fd,buffer+nwritten,len - nwritten);
 166                 if (ret <= 0) {
 167                         DEBUG(0,("Error writing %d bytes to client. %d. (%s)\n",
 168                                 (int)len,(int)ret, strerror(errno) ));
 169                         return false;
 170                 }
 171                 nwritten += ret;
 172         }
 173
 174         return true;
 175 }
 176
 177 static void filter_child(int c, struct sockaddr_storage *dest_ss)
 178 {
 179         NTSTATUS status;
 180         int s = -1;
 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
 185         if (s == -1) {
 186                 char addr[INET6_ADDRSTRLEN];
 187                 if (dest_ss) {
 188                         print_sockaddr(addr, sizeof(addr), dest_ss);
 189                 }
 190
 191                 d_printf("Unable to connect to %s (%s)\n",
 192                          dest_ss?addr:"NULL",strerror(errno));
 193                 exit(1);
 194         }
 195
 196         while (c != -1 || s != -1) {
 197                 struct pollfd fds[2];
 198                 int num_fds, ret;
 199
 200                 memset(fds, 0, sizeof(struct pollfd) * 2);
 201                 fds[0].fd = -1;
 202                 fds[1].fd = -1;
 203                 num_fds = 0;
 204
 205                 if (s != -1) {
 206                         fds[num_fds].fd = s;
 207                         fds[num_fds].events = POLLIN|POLLHUP;
 208                         num_fds += 1;
 209                 }
 210                 if (c != -1) {
 211                         fds[num_fds].fd = c;
 212                         fds[num_fds].events = POLLIN|POLLHUP;
 213                         num_fds += 1;
 214                 }
 215
 216                 ret = sys_poll_intr(fds, num_fds, -1);
 217                 if (ret <= 0) {
 218                         continue;
 219                 }
 220
 221                 /*
 222                  * find c in fds and see if it's readable
 223                  */
 224                 if ((c != -1) &&
 225                     (((fds[0].fd == c)
 226                       && (fds[0].revents & (POLLIN|POLLHUP|POLLERR))) ||
 227                      ((fds[1].fd == c)
 228                       && (fds[1].revents & (POLLIN|POLLHUP|POLLERR))))) {
 229                         size_t len;
 230                         if (!NT_STATUS_IS_OK(receive_smb_raw(
 231                                                         c, packet, sizeof(packet),
 232                                                         0, 0, &len))) {
 233                                 d_printf("client closed connection\n");
 234                                 exit(0);
 235                         }
 236                         filter_request(packet, len);
 237                         if (!send_smb(s, packet)) {
 238                                 d_printf("server is dead\n");
 239                                 exit(1);
 240                         }
 241                 }
 242
 243                 /*
 244                  * find s in fds and see if it's readable
 245                  */
 246                 if ((s != -1) &&
 247                     (((fds[0].fd == s)
 248                       && (fds[0].revents & (POLLIN|POLLHUP|POLLERR))) ||
 249                      ((fds[1].fd == s)
 250                       && (fds[1].revents & (POLLIN|POLLHUP|POLLERR))))) {
 251                         size_t len;
 252                         if (!NT_STATUS_IS_OK(receive_smb_raw(
 253                                                         s, packet, sizeof(packet),
 254                                                         0, 0, &len))) {
 255                                 d_printf("server closed connection\n");
 256                                 exit(0);
 257                         }
 258                         filter_reply(packet);
 259                         if (!send_smb(c, packet)) {
 260                                 d_printf("client is dead\n");
 261                                 exit(1);
 262                         }
 263                 }
 264         }
 265         d_printf("Connection closed\n");
 266         exit(0);
 267 }
 268
 269
 270 static void start_filter(char *desthost)
 271 {
 272         int s, c;
 273         struct sockaddr_storage dest_ss;
 274         struct sockaddr_storage my_ss;
 275
 276         CatchChild();
 277
 278         /* start listening on port 445 locally */
 279
 280         zero_sockaddr(&my_ss);
 281         s = open_socket_in(SOCK_STREAM, TCP_SMB_PORT, 0, &my_ss, True);
 282
 283         if (s == -1) {
 284                 d_printf("bind failed\n");
 285                 exit(1);
 286         }
 287
 288         if (listen(s, 5) == -1) {
 289                 d_printf("listen failed\n");
 290         }
 291
 292         if (!resolve_name(desthost, &dest_ss, 0x20, false)) {
 293                 d_printf("Unable to resolve host %s\n", desthost);
 294                 exit(1);
 295         }
 296
 297         while (1) {
 298                 int num, revents;
 299                 struct sockaddr_storage ss;
 300                 socklen_t in_addrlen = sizeof(ss);
 301
 302                 num = poll_intr_one_fd(s, POLLIN|POLLHUP, -1, &revents);
 303                 if ((num > 0) && (revents & (POLLIN|POLLHUP|POLLERR))) {
 304                         c = accept(s, (struct sockaddr *)&ss, &in_addrlen);
 305                         if (c != -1) {
 306                                 if (fork() == 0) {
 307                                         close(s);
 308                                         filter_child(c, &dest_ss);
 309                                         exit(0);
 310                                 } else {
 311                                         close(c);
 312                                 }
 313                         }
 314                 }
 315         }
 316 }
 317
 318
 319 int main(int argc, char *argv[])
 320 {
 321         char *desthost;
 322         const char *configfile;
 323         TALLOC_CTX *frame = talloc_stackframe();
 324
 325         load_case_tables();
 326
 327         setup_logging(argv[0], DEBUG_STDOUT);
 328
 329         configfile = get_dyn_CONFIGFILE();
 330
 331         if (argc < 2) {
 332                 fprintf(stderr,"smbfilter <desthost> <netbiosname>\n");
 333                 exit(1);
 334         }
 335
 336         desthost = argv[1];
 337         if (argc > 2) {
 338                 netbiosname = argv[2];
 339         }
 340
 341         if (!lp_load_global(configfile)) {
 342                 d_printf("Unable to load config file\n");
 343         }
 344
 345         start_filter(desthost);
 346         TALLOC_FREE(frame);
 347         return 0;
 348 }