usr.sbin/ppp/filter.c

   1 /*-
   2  * Copyright (c) 1996 - 2001 Brian Somers <brian@Awfulhak.org>
   3  *          based on work by Toshiharu OHNO <tony-o@iij.ad.jp>
   4  *                           Internet Initiative Japan, Inc (IIJ)
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  *
  28  * $FreeBSD: src/usr.sbin/ppp/filter.c,v 1.39.2.7 2002/09/01 02:12:26 brian Exp $
  29  */
  30
  31 #include <sys/param.h>
  32 #include <netinet/in.h>
  33 #include <netdb.h>
  34 #include <netinet/in_systm.h>
  35 #include <netinet/ip.h>
  36 #include <sys/socket.h>
  37 #include <sys/un.h>
  38
  39 #include <stdarg.h>
  40 #include <stdio.h>
  41 #include <stdlib.h>
  42 #include <string.h>
  43 #include <termios.h>
  44
  45 #include "layer.h"
  46 #include "defs.h"
  47 #include "command.h"
  48 #include "mbuf.h"
  49 #include "log.h"
  50 #include "iplist.h"
  51 #include "timer.h"
  52 #include "throughput.h"
  53 #include "lqr.h"
  54 #include "hdlc.h"
  55 #include "fsm.h"
  56 #include "lcp.h"
  57 #include "ccp.h"
  58 #include "link.h"
  59 #include "slcompress.h"
  60 #include "ncpaddr.h"
  61 #include "ipcp.h"
  62 #include "filter.h"
  63 #include "descriptor.h"
  64 #include "prompt.h"
  65 #include "mp.h"
  66 #ifndef NORADIUS
  67 #include "radius.h"
  68 #endif
  69 #include "ipv6cp.h"
  70 #include "ncp.h"
  71 #include "bundle.h"
  72
  73 static unsigned filter_Nam2Op(const char *);
  74
  75 static int
  76 ParsePort(const char *service, const char *proto)
  77 {
  78   struct servent *servent;
  79   char *cp;
  80   int port;
  81
  82   servent = getservbyname(service, proto);
  83   if (servent != NULL)
  84     return ntohs(servent->s_port);
  85
  86   port = strtol(service, &cp, 0);
  87   if (cp == service) {
  88     log_Printf(LogWARN, "ParsePort: %s is not a port name or number.\n",
  89               service);
  90     return 0;
  91   }
  92   return port;
  93 }
  94
  95 /*
  96  *      ICMP Syntax:    src eq icmp_message_type
  97  */
  98 static int
  99 ParseIcmp(int argc, char const *const *argv, struct filterent *tgt)
 100 {
 101   int type;
 102   char *cp;
 103
 104   switch (argc) {
 105   case 0:
 106     /* permit/deny all ICMP types */
 107     tgt->f_srcop = tgt->f_dstop = OP_NONE;
 108     break;
 109
 110   case 3:
 111     if (!strcmp(*argv, "src") && !strcmp(argv[1], "eq")) {
 112       type = strtol(argv[2], &cp, 0);
 113       if (cp == argv[2]) {
 114         log_Printf(LogWARN, "ParseIcmp: type is expected.\n");
 115         return 0;
 116       }
 117       tgt->f_srcop = OP_EQ;
 118       tgt->f_srcport = type;
 119       tgt->f_dstop = OP_NONE;
 120     }
 121     break;
 122
 123   default:
 124     log_Printf(LogWARN, "ParseIcmp: bad icmp syntax.\n");
 125     return 0;
 126   }
 127   return 1;
 128 }
 129
 130 /*
 131  *      UDP Syntax: [src op port] [dst op port]
 132  */
 133 static int
 134 ParseUdpOrTcp(int argc, char const *const *argv, const struct protoent *pe,
 135               struct filterent *tgt)
 136 {
 137   tgt->f_srcop = tgt->f_dstop = OP_NONE;
 138   tgt->f_estab = tgt->f_syn = tgt->f_finrst = 0;
 139
 140   if (argc >= 3 && !strcmp(*argv, "src")) {
 141     tgt->f_srcop = filter_Nam2Op(argv[1]);
 142     if (tgt->f_srcop == OP_NONE) {
 143       log_Printf(LogWARN, "ParseUdpOrTcp: bad operator\n");
 144       return 0;
 145     }
 146     if (pe == NULL)
 147       return 0;
 148     tgt->f_srcport = ParsePort(argv[2], pe->p_name);
 149     if (tgt->f_srcport == 0)
 150       return 0;
 151     argc -= 3;
 152     argv += 3;
 153   }
 154
 155   if (argc >= 3 && !strcmp(argv[0], "dst")) {
 156     tgt->f_dstop = filter_Nam2Op(argv[1]);
 157     if (tgt->f_dstop == OP_NONE) {
 158       log_Printf(LogWARN, "ParseUdpOrTcp: bad operator\n");
 159       return 0;
 160     }
 161     if (pe == NULL)
 162       return 0;
 163     tgt->f_dstport = ParsePort(argv[2], pe->p_name);
 164     if (tgt->f_dstport == 0)
 165       return 0;
 166     argc -= 3;
 167     argv += 3;
 168   }
 169
 170   if (pe && pe->p_proto == IPPROTO_TCP) {
 171     for (; argc > 0; argc--, argv++)
 172       if (!strcmp(*argv, "estab"))
 173         tgt->f_estab = 1;
 174       else if (!strcmp(*argv, "syn"))
 175         tgt->f_syn = 1;
 176       else if (!strcmp(*argv, "finrst"))
 177         tgt->f_finrst = 1;
 178       else
 179         break;
 180   }
 181
 182   if (argc > 0) {
 183     log_Printf(LogWARN, "ParseUdpOrTcp: bad src/dst port syntax: %s\n", *argv);
 184     return 0;
 185   }
 186
 187   return 1;
 188 }
 189
 190 static int
 191 ParseGeneric(int argc, struct filterent *tgt)
 192 {
 193   /*
 194    * Filter currently is a catch-all. Requests are either permitted or
 195    * dropped.
 196    */
 197   if (argc != 0) {
 198     log_Printf(LogWARN, "ParseGeneric: Too many parameters\n");
 199     return 0;
 200   } else
 201     tgt->f_srcop = tgt->f_dstop = OP_NONE;
 202
 203   return 1;
 204 }
 205
 206 static unsigned
 207 addrtype(const char *addr)
 208 {
 209   if (!strncasecmp(addr, "MYADDR", 6) && (addr[6] == '\0' || addr[6] == '/'))
 210     return T_MYADDR;
 211   if (!strncasecmp(addr, "MYADDR6", 7) && (addr[7] == '\0' || addr[7] == '/'))
 212     return T_MYADDR6;
 213   if (!strncasecmp(addr, "HISADDR", 7) && (addr[7] == '\0' || addr[7] == '/'))
 214     return T_HISADDR;
 215   if (!strncasecmp(addr, "HISADDR6", 8) && (addr[8] == '\0' || addr[8] == '/'))
 216     return T_HISADDR6;
 217   if (!strncasecmp(addr, "DNS0", 4) && (addr[4] == '\0' || addr[4] == '/'))
 218     return T_DNS0;
 219   if (!strncasecmp(addr, "DNS1", 4) && (addr[4] == '\0' || addr[4] == '/'))
 220     return T_DNS1;
 221
 222   return T_ADDR;
 223 }
 224
 225 static const char *
 226 addrstr(struct ncprange *addr, unsigned type)
 227 {
 228   switch (type) {
 229     case T_MYADDR:
 230       return "MYADDR";
 231     case T_HISADDR:
 232       return "HISADDR";
 233     case T_DNS0:
 234       return "DNS0";
 235     case T_DNS1:
 236       return "DNS1";
 237   }
 238   return ncprange_ntoa(addr);
 239 }
 240
 241 static int
 242 filter_Parse(struct ncp *ncp, int argc, char const *const *argv,
 243              struct filterent *ofp)
 244 {
 245   struct filterent fe;
 246   struct protoent *pe;
 247   char *wp;
 248   int action, family, ruleno, val, width;
 249
 250   ruleno = strtol(*argv, &wp, 0);
 251   if (*argv == wp || ruleno >= MAXFILTERS) {
 252     log_Printf(LogWARN, "Parse: invalid filter number.\n");
 253     return 0;
 254   }
 255   if (ruleno < 0) {
 256     for (ruleno = 0; ruleno < MAXFILTERS; ruleno++) {
 257       ofp->f_action = A_NONE;
 258       ofp++;
 259     }
 260     log_Printf(LogWARN, "Parse: filter cleared.\n");
 261     return 1;
 262   }
 263   ofp += ruleno;
 264
 265   if (--argc == 0) {
 266     log_Printf(LogWARN, "Parse: missing action.\n");
 267     return 0;
 268   }
 269   argv++;
 270
 271   memset(&fe, '\0', sizeof fe);
 272
 273   val = strtol(*argv, &wp, 0);
 274   if (!*wp && val >= 0 && val < MAXFILTERS) {
 275     if (val <= ruleno) {
 276       log_Printf(LogWARN, "Parse: Can only jump forward from rule %d\n",
 277                  ruleno);
 278       return 0;
 279     }
 280     action = val;
 281   } else if (!strcmp(*argv, "permit")) {
 282     action = A_PERMIT;
 283   } else if (!strcmp(*argv, "deny")) {
 284     action = A_DENY;
 285   } else if (!strcmp(*argv, "clear")) {
 286     ofp->f_action = A_NONE;
 287     return 1;
 288   } else {
 289     log_Printf(LogWARN, "Parse: %s: bad action\n", *argv);
 290     return 0;
 291   }
 292   fe.f_action = action;
 293
 294   argc--;
 295   argv++;
 296
 297   if (argc && argv[0][0] == '!' && !argv[0][1]) {
 298     fe.f_invert = 1;
 299     argc--;
 300     argv++;
 301   }
 302
 303   ncprange_init(&fe.f_src);
 304   ncprange_init(&fe.f_dst);
 305
 306   if (argc == 0)
 307     pe = NULL;
 308   else if ((pe = getprotobyname(*argv)) == NULL && strcmp(*argv, "all") != 0) {
 309     if (argc < 2) {
 310       log_Printf(LogWARN, "Parse: Protocol or address pair expected\n");
 311       return 0;
 312     } else if (strcasecmp(*argv, "any") == 0 ||
 313                ncprange_aton(&fe.f_src, ncp, *argv)) {
 314       family = ncprange_family(&fe.f_src);
 315       if (!ncprange_getwidth(&fe.f_src, &width))
 316         width = 0;
 317       if (width == 0)
 318         ncprange_init(&fe.f_src);
 319       fe.f_srctype = addrtype(*argv);
 320       argc--;
 321       argv++;
 322
 323       if (strcasecmp(*argv, "any") == 0 ||
 324           ncprange_aton(&fe.f_dst, ncp, *argv)) {
 325         if (ncprange_family(&fe.f_dst) != AF_UNSPEC &&
 326             ncprange_family(&fe.f_src) != AF_UNSPEC &&
 327             family != ncprange_family(&fe.f_dst)) {
 328           log_Printf(LogWARN, "Parse: src and dst address families differ\n");
 329           return 0;
 330         }
 331         if (!ncprange_getwidth(&fe.f_dst, &width))
 332           width = 0;
 333         if (width == 0)
 334           ncprange_init(&fe.f_dst);
 335         fe.f_dsttype = addrtype(*argv);
 336         argc--;
 337         argv++;
 338       } else {
 339         log_Printf(LogWARN, "Parse: Protocol or address pair expected\n");
 340         return 0;
 341       }
 342
 343       if (argc) {
 344         if ((pe = getprotobyname(*argv)) == NULL && strcmp(*argv, "all") != 0) {
 345           log_Printf(LogWARN, "Parse: %s: Protocol expected\n", *argv);
 346           return 0;
 347         } else {
 348           argc--;
 349           argv++;
 350         }
 351       }
 352     } else {
 353       log_Printf(LogWARN, "Parse: Protocol or address pair expected\n");
 354       return 0;
 355     }
 356   } else {
 357     argc--;
 358     argv++;
 359   }
 360
 361   if (argc >= 2 && strcmp(*argv, "timeout") == 0) {
 362     fe.timeout = strtoul(argv[1], NULL, 10);
 363     argc -= 2;
 364     argv += 2;
 365   }
 366
 367   val = 1;
 368   fe.f_proto = (pe == NULL) ? 0 : pe->p_proto;
 369
 370   switch (fe.f_proto) {
 371   case IPPROTO_TCP:
 372   case IPPROTO_UDP:
 373   case IPPROTO_IPIP:
 374 #ifndef NOINET6
 375   case IPPROTO_IPV6:
 376 #endif
 377     val = ParseUdpOrTcp(argc, argv, pe, &fe);
 378     break;
 379   case IPPROTO_ICMP:
 380 #ifndef NOINET6
 381   case IPPROTO_ICMPV6:
 382 #endif
 383     val = ParseIcmp(argc, argv, &fe);
 384     break;
 385   default:
 386     val = ParseGeneric(argc, &fe);
 387     break;
 388   }
 389
 390   log_Printf(LogDEBUG, "Parse: Src: %s\n", ncprange_ntoa(&fe.f_src));
 391   log_Printf(LogDEBUG, "Parse: Dst: %s\n", ncprange_ntoa(&fe.f_dst));
 392   log_Printf(LogDEBUG, "Parse: Proto: %d\n", fe.f_proto);
 393
 394   log_Printf(LogDEBUG, "Parse: src:  %s (%d)\n",
 395             filter_Op2Nam(fe.f_srcop), fe.f_srcport);
 396   log_Printf(LogDEBUG, "Parse: dst:  %s (%d)\n",
 397             filter_Op2Nam(fe.f_dstop), fe.f_dstport);
 398   log_Printf(LogDEBUG, "Parse: estab: %u\n", fe.f_estab);
 399   log_Printf(LogDEBUG, "Parse: syn: %u\n", fe.f_syn);
 400   log_Printf(LogDEBUG, "Parse: finrst: %u\n", fe.f_finrst);
 401
 402   if (val)
 403     *ofp = fe;
 404
 405   return val;
 406 }
 407
 408 int
 409 filter_Set(struct cmdargs const *arg)
 410 {
 411   struct filter *filter;
 412
 413   if (arg->argc < arg->argn+2)
 414     return -1;
 415
 416   if (!strcmp(arg->argv[arg->argn], "in"))
 417     filter = &arg->bundle->filter.in;
 418   else if (!strcmp(arg->argv[arg->argn], "out"))
 419     filter = &arg->bundle->filter.out;
 420   else if (!strcmp(arg->argv[arg->argn], "dial"))
 421     filter = &arg->bundle->filter.dial;
 422   else if (!strcmp(arg->argv[arg->argn], "alive"))
 423     filter = &arg->bundle->filter.alive;
 424   else {
 425     log_Printf(LogWARN, "filter_Set: %s: Invalid filter name.\n",
 426               arg->argv[arg->argn]);
 427     return -1;
 428   }
 429
 430   filter_Parse(&arg->bundle->ncp, arg->argc - arg->argn - 1,
 431         arg->argv + arg->argn + 1, filter->rule);
 432   return 0;
 433 }
 434
 435 const char *
 436 filter_Action2Nam(unsigned act)
 437 {
 438   static const char * const actname[] = { "  none ", "permit ", "  deny " };
 439   static char buf[8];
 440
 441   if (act < MAXFILTERS) {
 442     snprintf(buf, sizeof buf, "%6d ", act);
 443     return buf;
 444   } else if (act >= A_NONE && act < A_NONE + sizeof(actname)/sizeof(char *))
 445     return actname[act - A_NONE];
 446   else
 447     return "?????? ";
 448 }
 449
 450 static void
 451 doShowFilter(struct filterent *fp, struct prompt *prompt)
 452 {
 453   struct protoent *pe;
 454   int n;
 455
 456   for (n = 0; n < MAXFILTERS; n++, fp++) {
 457     if (fp->f_action != A_NONE) {
 458       prompt_Printf(prompt, "  %2d %s", n, filter_Action2Nam(fp->f_action));
 459       prompt_Printf(prompt, "%c ", fp->f_invert ? '!' : ' ');
 460
 461       if (ncprange_isset(&fp->f_src))
 462         prompt_Printf(prompt, "%s ", addrstr(&fp->f_src, fp->f_srctype));
 463       else
 464         prompt_Printf(prompt, "any ");
 465
 466       if (ncprange_isset(&fp->f_dst))
 467         prompt_Printf(prompt, "%s ", addrstr(&fp->f_dst, fp->f_dsttype));
 468       else
 469         prompt_Printf(prompt, "any ");
 470
 471       if (fp->f_proto) {
 472         if ((pe = getprotobynumber(fp->f_proto)) == NULL)
 473           prompt_Printf(prompt, "P:%d", fp->f_proto);
 474         else
 475           prompt_Printf(prompt, "%s", pe->p_name);
 476
 477         if (fp->f_srcop)
 478           prompt_Printf(prompt, " src %s %d", filter_Op2Nam(fp->f_srcop),
 479                   fp->f_srcport);
 480         if (fp->f_dstop)
 481           prompt_Printf(prompt, " dst %s %d", filter_Op2Nam(fp->f_dstop),
 482                   fp->f_dstport);
 483         if (fp->f_estab)
 484           prompt_Printf(prompt, " estab");
 485         if (fp->f_syn)
 486           prompt_Printf(prompt, " syn");
 487         if (fp->f_finrst)
 488           prompt_Printf(prompt, " finrst");
 489       } else
 490         prompt_Printf(prompt, "all");
 491       if (fp->timeout != 0)
 492           prompt_Printf(prompt, " timeout %u", fp->timeout);
 493       prompt_Printf(prompt, "\n");
 494     }
 495   }
 496 }
 497
 498 int
 499 filter_Show(struct cmdargs const *arg)
 500 {
 501   if (arg->argc > arg->argn+1)
 502     return -1;
 503
 504   if (arg->argc == arg->argn+1) {
 505     struct filter *filter;
 506
 507     if (!strcmp(arg->argv[arg->argn], "in"))
 508       filter = &arg->bundle->filter.in;
 509     else if (!strcmp(arg->argv[arg->argn], "out"))
 510       filter = &arg->bundle->filter.out;
 511     else if (!strcmp(arg->argv[arg->argn], "dial"))
 512       filter = &arg->bundle->filter.dial;
 513     else if (!strcmp(arg->argv[arg->argn], "alive"))
 514       filter = &arg->bundle->filter.alive;
 515     else
 516       return -1;
 517     doShowFilter(filter->rule, arg->prompt);
 518   } else {
 519     struct filter *filter[4];
 520     int f;
 521
 522     filter[0] = &arg->bundle->filter.in;
 523     filter[1] = &arg->bundle->filter.out;
 524     filter[2] = &arg->bundle->filter.dial;
 525     filter[3] = &arg->bundle->filter.alive;
 526     for (f = 0; f < 4; f++) {
 527       if (f)
 528         prompt_Printf(arg->prompt, "\n");
 529       prompt_Printf(arg->prompt, "%s:\n", filter[f]->name);
 530       doShowFilter(filter[f]->rule, arg->prompt);
 531     }
 532   }
 533
 534   return 0;
 535 }
 536
 537 static const char * const opname[] = {"none", "eq", "gt", "lt"};
 538
 539 const char *
 540 filter_Op2Nam(unsigned op)
 541 {
 542   if (op >= sizeof opname / sizeof opname[0])
 543     return "unknown";
 544   return opname[op];
 545
 546 }
 547
 548 static unsigned
 549 filter_Nam2Op(const char *cp)
 550 {
 551   unsigned op;
 552
 553   for (op = sizeof opname / sizeof opname[0] - 1; op; op--)
 554     if (!strcasecmp(cp, opname[op]))
 555       break;
 556
 557   return op;
 558 }
 559
 560 void
 561 filter_AdjustAddr(struct filter *filter, struct ncpaddr *local,
 562                   struct ncpaddr *remote, struct in_addr *dns)
 563 {
 564   struct filterent *fp;
 565   int n;
 566
 567   for (fp = filter->rule, n = 0; n < MAXFILTERS; fp++, n++)
 568     if (fp->f_action != A_NONE) {
 569       if (local) {
 570         if (fp->f_srctype == T_MYADDR && ncpaddr_family(local) == AF_INET)
 571           ncprange_sethost(&fp->f_src, local);
 572         if (fp->f_dsttype == T_MYADDR && ncpaddr_family(local) == AF_INET)
 573           ncprange_sethost(&fp->f_dst, local);
 574 #ifndef NOINET6
 575         if (fp->f_srctype == T_MYADDR6 && ncpaddr_family(local) == AF_INET6)
 576           ncprange_sethost(&fp->f_src, local);
 577         if (fp->f_dsttype == T_MYADDR6 && ncpaddr_family(local) == AF_INET6)
 578           ncprange_sethost(&fp->f_dst, local);
 579 #endif
 580       }
 581       if (remote) {
 582         if (fp->f_srctype == T_HISADDR && ncpaddr_family(remote) == AF_INET)
 583           ncprange_sethost(&fp->f_src, remote);
 584         if (fp->f_dsttype == T_HISADDR && ncpaddr_family(remote) == AF_INET)
 585           ncprange_sethost(&fp->f_dst, remote);
 586 #ifndef NOINET6
 587         if (fp->f_srctype == T_HISADDR6 && ncpaddr_family(remote) == AF_INET6)
 588           ncprange_sethost(&fp->f_src, remote);
 589         if (fp->f_dsttype == T_HISADDR6 && ncpaddr_family(remote) == AF_INET6)
 590           ncprange_sethost(&fp->f_dst, remote);
 591 #endif
 592       }
 593       if (dns) {
 594         if (fp->f_srctype == T_DNS0)
 595           ncprange_setip4host(&fp->f_src, dns[0]);
 596         if (fp->f_dsttype == T_DNS0)
 597           ncprange_setip4host(&fp->f_dst, dns[0]);
 598         if (fp->f_srctype == T_DNS1)
 599           ncprange_setip4host(&fp->f_src, dns[1]);
 600         if (fp->f_dsttype == T_DNS1)
 601           ncprange_setip4host(&fp->f_dst, dns[1]);
 602       }
 603     }
 604 }