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