contrib/ipfilter/common.c

   1 /*
   2  * Copyright (C) 1993-2001 by Darren Reed.
   3  *
   4  * See the IPFILTER.LICENCE file for details on licencing.
   5  */
   6 #if defined(__sgi) && (IRIX > 602)
   7 # include <sys/ptimers.h>
   8 #endif
   9 #include <sys/types.h>
  10 #if !defined(__SVR4) && !defined(__svr4__)
  11 #include <strings.h>
  12 #else
  13 #include <sys/byteorder.h>
  14 #endif
  15 #include <sys/param.h>
  16 #include <sys/time.h>
  17 #include <sys/socket.h>
  18 #include <netinet/in.h>
  19 #include <netinet/in_systm.h>
  20 #include <netinet/ip.h>
  21 #include <netinet/tcp.h>
  22 #include <net/if.h>
  23 #if __FreeBSD_version >= 300000
  24 # include <net/if_var.h>
  25 #endif
  26 #include <stdio.h>
  27 #include <string.h>
  28 #include <limits.h>
  29 #include <stdlib.h>
  30 #include <unistd.h>
  31 #include <stddef.h>
  32 #include <netdb.h>
  33 #include <arpa/nameser.h>
  34 #include <arpa/inet.h>
  35 #include <resolv.h>
  36 #include <ctype.h>
  37 #include <syslog.h>
  38 #include "ip_compat.h"
  39 #include "ip_fil.h"
  40 #include "ipf.h"
  41 #include "facpri.h"
  42
  43 #if !defined(lint)
  44 static const char sccsid[] = "@(#)parse.c       1.44 6/5/96 (C) 1993-2000 Darren Reed";
  45 static const char rcsid[] = "@(#)$IPFilter: parse.c,v 2.8 1999/12/28 10:49:46 darrenr Exp $";
  46 #endif
  47
  48 extern  struct  ipopt_names     ionames[], secclass[];
  49 extern  int     opts;
  50 extern  int     use_inet6;
  51
  52
  53 char    *proto = NULL;
  54 char    flagset[] = "FSRPAUEC";
  55 u_char  flags[] = { TH_FIN, TH_SYN, TH_RST, TH_PUSH, TH_ACK, TH_URG,
  56                     TH_ECN, TH_CWR };
  57
  58 void fill6bits __P((int, u_32_t *));
  59 int count6bits __P((u_32_t *));
  60
  61 static  char    thishost[MAXHOSTNAMELEN];
  62
  63
  64 void initparse()
  65 {
  66         gethostname(thishost, sizeof(thishost));
  67         thishost[sizeof(thishost) - 1] = '\0';
  68 }
  69
  70
  71 int genmask(msk, mskp)
  72 char *msk;
  73 u_32_t *mskp;
  74 {
  75         char *endptr = NULL;
  76 #ifdef  USE_INET6
  77         u_32_t addr;
  78 #endif
  79         int bits;
  80
  81         if (index(msk, '.') || index(msk, 'x') || index(msk, ':')) {
  82                 /* possibly of the form xxx.xxx.xxx.xxx
  83                  * or 0xYYYYYYYY */
  84 #ifdef  USE_INET6
  85                 if (use_inet6) {
  86                         if (inet_pton(AF_INET6, msk, &addr) != 1)
  87                                 return -1;
  88                 } else
  89 #endif
  90                 if (inet_aton(msk, (struct in_addr *)mskp) == 0)
  91                         return -1;
  92         } else {
  93                 /*
  94                  * set x most significant bits
  95                  */
  96                 bits = (int)strtol(msk, &endptr, 0);
  97                 if ((*endptr != '\0') ||
  98                     ((bits > 32) && !use_inet6) || (bits < 0) ||
  99                     ((bits > 128) && use_inet6))
 100                         return -1;
 101                 if (use_inet6)
 102                         fill6bits(bits, mskp);
 103                 else {
 104                         if (bits == 0)
 105                                 *mskp = 0;
 106                         else
 107                                 *mskp = htonl(0xffffffff << (32 - bits));
 108                 }
 109         }
 110         return 0;
 111 }
 112
 113
 114
 115 void fill6bits(bits, msk)
 116 int bits;
 117 u_32_t *msk;
 118 {
 119         int i;
 120
 121         for (i = 0; bits >= 32 && i < 4 ; ++i, bits -= 32)
 122                 msk[i] = 0xffffffff;
 123
 124         if (bits > 0 && i < 4)
 125                 msk[i++] = htonl(0xffffffff << (32 - bits));
 126
 127         while (i < 4)
 128                 msk[i++] = 0;
 129 }
 130
 131
 132 /*
 133  * returns -1 if neither "hostmask/num" or "hostmask mask addr" are
 134  * found in the line segments, there is an error processing this information,
 135  * or there is an error processing ports information.
 136  */
 137 int     hostmask(seg, sa, msk, pp, cp, tp, linenum)
 138 char    ***seg;
 139 u_32_t  *sa, *msk;
 140 u_short *pp, *tp;
 141 int     *cp;
 142 int     linenum;
 143 {
 144         struct in_addr maskaddr;
 145         char *s;
 146
 147         /*
 148          * is it possibly hostname/num ?
 149          */
 150         if ((s = index(**seg, '/')) ||
 151             ((s = index(**seg, ':')) && !index(s + 1, ':'))) {
 152                 *s++ = '\0';
 153                 if (genmask(s, msk) == -1) {
 154                         fprintf(stderr, "%d: bad mask (%s)\n", linenum, s);
 155                         return -1;
 156                 }
 157                 if (hostnum(sa, **seg, linenum) == -1) {
 158                         fprintf(stderr, "%d: bad host (%s)\n", linenum, **seg);
 159                         return -1;
 160                 }
 161                 *sa &= *msk;
 162                 (*seg)++;
 163                 return ports(seg, pp, cp, tp, linenum);
 164         }
 165
 166         /*
 167          * look for extra segments if "mask" found in right spot
 168          */
 169         if (*(*seg+1) && *(*seg+2) && !strcasecmp(*(*seg+1), "mask")) {
 170                 if (hostnum(sa, **seg, linenum) == -1) {
 171                         fprintf(stderr, "%d: bad host (%s)\n", linenum, **seg);
 172                         return -1;
 173                 }
 174                 (*seg)++;
 175                 (*seg)++;
 176                 if (inet_aton(**seg, &maskaddr) == 0) {
 177                         fprintf(stderr, "%d: bad mask (%s)\n", linenum, **seg);
 178                         return -1;
 179                 }
 180                 *msk = maskaddr.s_addr;
 181                 (*seg)++;
 182                 *sa &= *msk;
 183                 return ports(seg, pp, cp, tp, linenum);
 184         }
 185
 186         if (**seg) {
 187                 if (hostnum(sa, **seg, linenum) == -1) {
 188                         fprintf(stderr, "%d: bad host (%s)\n", linenum, **seg);
 189                         return -1;
 190                 }
 191                 (*seg)++;
 192                 if (use_inet6) {
 193                         u_32_t k = 0;
 194                         if (sa[0] || sa[1] || sa[2] || sa[3])
 195                                 k = 0xffffffff;
 196                         msk[0] = msk[1] = msk[2] = msk[3] = k;
 197                 }
 198                 else
 199                         *msk = *sa ? 0xffffffff : 0;
 200                 return ports(seg, pp, cp, tp, linenum);
 201         }
 202         fprintf(stderr, "%d: bad host (%s)\n", linenum, **seg);
 203         return -1;
 204 }
 205
 206 /*
 207  * returns an ip address as a long var as a result of either a DNS lookup or
 208  * straight inet_addr() call
 209  */
 210 int     hostnum(ipa, host, linenum)
 211 u_32_t  *ipa;
 212 char    *host;
 213 int     linenum;
 214 {
 215         struct  hostent *hp;
 216         struct  netent  *np;
 217         struct  in_addr ip;
 218
 219         if (!strcasecmp("any", host))
 220                 return 0;
 221 #ifdef  USE_INET6
 222         if (use_inet6) {
 223                 if (inet_pton(AF_INET6, host, ipa) == 1)
 224                         return 0;
 225                 else
 226                         return -1;
 227         }
 228 #endif
 229         if (isdigit(*host) && inet_aton(host, &ip)) {
 230                 *ipa = ip.s_addr;
 231                 return 0;
 232         }
 233
 234         if (!strcasecmp("<thishost>", host))
 235                 host = thishost;
 236
 237         if (!(hp = gethostbyname(host))) {
 238                 if (!(np = getnetbyname(host))) {
 239                         fprintf(stderr, "%d: can't resolve hostname: %s\n",
 240                                 linenum, host);
 241                         return -1;
 242                 }
 243                 *ipa = htonl(np->n_net);
 244                 return 0;
 245         }
 246         *ipa = *(u_32_t *)hp->h_addr;
 247         return 0;
 248 }
 249
 250
 251 /*
 252  * check for possible presence of the port fields in the line
 253  */
 254 int     ports(seg, pp, cp, tp, linenum)
 255 char    ***seg;
 256 u_short *pp, *tp;
 257 int     *cp;
 258 int     linenum;
 259 {
 260         int     comp = -1;
 261
 262         if (!*seg || !**seg || !***seg)
 263                 return 0;
 264         if (!strcasecmp(**seg, "port") && *(*seg + 1) && *(*seg + 2)) {
 265                 (*seg)++;
 266                 if (!strcmp(**seg, "=") || !strcasecmp(**seg, "eq"))
 267                         comp = FR_EQUAL;
 268                 else if (!strcmp(**seg, "!=") || !strcasecmp(**seg, "ne"))
 269                         comp = FR_NEQUAL;
 270                 else if (!strcmp(**seg, "<") || !strcasecmp(**seg, "lt"))
 271                         comp = FR_LESST;
 272                 else if (!strcmp(**seg, ">") || !strcasecmp(**seg, "gt"))
 273                         comp = FR_GREATERT;
 274                 else if (!strcmp(**seg, "<=") || !strcasecmp(**seg, "le"))
 275                         comp = FR_LESSTE;
 276                 else if (!strcmp(**seg, ">=") || !strcasecmp(**seg, "ge"))
 277                         comp = FR_GREATERTE;
 278                 else if (isalnum(***seg) && *(*seg + 2)) {
 279                         if (portnum(**seg, pp, linenum) == 0)
 280                                 return -1;
 281                         (*seg)++;
 282                         if (!strcmp(**seg, "<>"))
 283                                 comp = FR_OUTRANGE;
 284                         else if (!strcmp(**seg, "><"))
 285                                 comp = FR_INRANGE;
 286                         else {
 287                                 fprintf(stderr,
 288                                         "%d: unknown range operator (%s)\n",
 289                                         linenum, **seg);
 290                                 return -1;
 291                         }
 292                         (*seg)++;
 293                         if (**seg == NULL) {
 294                                 fprintf(stderr, "%d: missing 2nd port value\n",
 295                                         linenum);
 296                                 return -1;
 297                         }
 298                         if (portnum(**seg, tp, linenum) == 0)
 299                                 return -1;
 300                 } else {
 301                         fprintf(stderr, "%d: unknown comparator (%s)\n",
 302                                         linenum, **seg);
 303                         return -1;
 304                 }
 305                 if (comp != FR_OUTRANGE && comp != FR_INRANGE) {
 306                         (*seg)++;
 307                         if (portnum(**seg, pp, linenum) == 0)
 308                                 return -1;
 309                 }
 310                 *cp = comp;
 311                 (*seg)++;
 312         }
 313         return 0;
 314 }
 315
 316
 317 /*
 318  * find the port number given by the name, either from getservbyname() or
 319  * straight atoi(). Return 1 on success, 0 on failure
 320  */
 321 int     portnum(name, port, linenum)
 322 char    *name;
 323 u_short *port;
 324 int     linenum;
 325 {
 326         struct  servent *sp, *sp2;
 327         u_short p1 = 0;
 328         int i;
 329
 330         if (isdigit(*name)) {
 331                 if (ratoi(name, &i, 0, USHRT_MAX)) {
 332                         *port = (u_short)i;
 333                         return 1;
 334                 }
 335                 fprintf(stderr, "%d: unknown port \"%s\"\n", linenum, name);
 336                 return 0;
 337         }
 338         if (proto != NULL && strcasecmp(proto, "tcp/udp") != 0) {
 339                 sp = getservbyname(name, proto);
 340                 if (sp) {
 341                         *port = ntohs(sp->s_port);
 342                         return 1;
 343                 }
 344                 fprintf(stderr, "%d: unknown service \"%s\".\n", linenum, name);
 345                 return 0;
 346         }
 347         sp = getservbyname(name, "tcp");
 348         if (sp)
 349                 p1 = sp->s_port;
 350         sp2 = getservbyname(name, "udp");
 351         if (!sp || !sp2) {
 352                 fprintf(stderr, "%d: unknown tcp/udp service \"%s\".\n",
 353                         linenum, name);
 354                 return 0;
 355         }
 356         if (p1 != sp2->s_port) {
 357                 fprintf(stderr, "%d: %s %d/tcp is a different port to ",
 358                         linenum, name, p1);
 359                 fprintf(stderr, "%d: %s %d/udp\n", linenum, name, sp->s_port);
 360                 return 0;
 361         }
 362         *port = ntohs(p1);
 363         return 1;
 364 }
 365
 366
 367 u_char tcp_flags(flgs, mask, linenum)
 368 char *flgs;
 369 u_char *mask;
 370 int    linenum;
 371 {
 372         u_char tcpf = 0, tcpfm = 0, *fp = &tcpf;
 373         char *s, *t;
 374
 375         if (*flgs == '0') {
 376                 s = strchr(flgs, '/');
 377                 if (s)
 378                         *s++ = '\0';
 379                 tcpf = strtol(flgs, NULL, 0);
 380                 fp = &tcpfm;
 381         } else
 382                 s = flgs;
 383
 384         for (; *s; s++) {
 385                 if (*s == '/' && fp == &tcpf) {
 386                         fp = &tcpfm;
 387                         if (*(s + 1) == '0')
 388                                 break;
 389                         continue;
 390                 }
 391                 if (!(t = index(flagset, *s))) {
 392                         fprintf(stderr, "%d: unknown flag (%c)\n", linenum, *s);
 393                         return 0;
 394                 }
 395                 *fp |= flags[t - flagset];
 396         }
 397
 398         if (s && *s == '0')
 399                 tcpfm = strtol(s, NULL, 0);
 400
 401         if (!tcpfm) {
 402                 if (tcpf == TH_SYN)
 403                         tcpfm = 0xff & ~(TH_ECN|TH_CWR);
 404                 else
 405                         tcpfm = 0xff & ~(TH_ECN);
 406         }
 407         *mask = tcpfm;
 408         return tcpf;
 409 }
 410
 411
 412 /*
 413  * count consecutive 1's in bit mask.  If the mask generated by counting
 414  * consecutive 1's is different to that passed, return -1, else return #
 415  * of bits.
 416  */
 417 int     countbits(ip)
 418 u_32_t  ip;
 419 {
 420         u_32_t  ipn;
 421         int     cnt = 0, i, j;
 422
 423         ip = ipn = ntohl(ip);
 424         for (i = 32; i; i--, ipn *= 2)
 425                 if (ipn & 0x80000000)
 426                         cnt++;
 427                 else
 428                         break;
 429         ipn = 0;
 430         for (i = 32, j = cnt; i; i--, j--) {
 431                 ipn *= 2;
 432                 if (j > 0)
 433                         ipn++;
 434         }
 435         if (ipn == ip)
 436                 return cnt;
 437         return -1;
 438 }
 439
 440
 441 int count6bits(msk)
 442 u_32_t *msk;
 443 {
 444         int i = 0, k;
 445         u_32_t j;
 446
 447         for (k = 3; k >= 0; k--)
 448                 if (msk[k] == 0xffffffff)
 449                         i += 32;
 450                 else {
 451                         for (j = msk[k]; j; j <<= 1)
 452                                 if (j & 0x80000000)
 453                                         i++;
 454                 }
 455         return i;
 456 }
 457
 458
 459 char    *portname(pr, port)
 460 int     pr, port;
 461 {
 462         static  char    buf[32];
 463         struct  protoent        *p = NULL;
 464         struct  servent *sv = NULL, *sv1 = NULL;
 465
 466         if (pr == -1) {
 467                 if ((sv = getservbyport(htons(port), "tcp"))) {
 468                         strncpy(buf, sv->s_name, sizeof(buf)-1);
 469                         buf[sizeof(buf)-1] = '\0';
 470                         sv1 = getservbyport(htons(port), "udp");
 471                         sv = strncasecmp(buf, sv->s_name, strlen(buf)) ?
 472                              NULL : sv1;
 473                 }
 474                 if (sv)
 475                         return buf;
 476         } else if (pr && (p = getprotobynumber(pr))) {
 477                 if ((sv = getservbyport(htons(port), p->p_name))) {
 478                         strncpy(buf, sv->s_name, sizeof(buf)-1);
 479                         buf[sizeof(buf)-1] = '\0';
 480                         return buf;
 481                 }
 482         }
 483
 484         (void) sprintf(buf, "%d", port);
 485         return buf;
 486 }
 487
 488
 489 int     ratoi(ps, pi, min, max)
 490 char    *ps;
 491 int     *pi, min, max;
 492 {
 493         int i;
 494         char *pe;
 495
 496         i = (int)strtol(ps, &pe, 0);
 497         if (*pe != '\0' || i < min || i > max)
 498                 return 0;
 499         *pi = i;
 500         return 1;
 501 }
 502
 503
 504 int     ratoui(ps, pi, min, max)
 505 char    *ps;
 506 u_int   *pi, min, max;
 507 {
 508         u_int i;
 509         char *pe;
 510
 511         i = (u_int)strtol(ps, &pe, 0);
 512         if (*pe != '\0' || i < min || i > max)
 513                 return 0;
 514         *pi = i;
 515         return 1;
 516 }
 517
 518
 519 void    printhostmask(v, addr, mask)
 520 int     v;
 521 u_32_t  *addr, *mask;
 522 {
 523         struct in_addr ipa;
 524         int ones;
 525
 526 #ifdef USE_INET6
 527         if (v == 6) {
 528                 ones = count6bits(mask);
 529                 if (ones == 0 && !addr[0] && !addr[1] && !addr[2] && !addr[3])
 530                         printf("any");
 531                 else {
 532                         char ipbuf[64];
 533                         printf("%s/%d",
 534                                inet_ntop(AF_INET6, addr, ipbuf, sizeof(ipbuf)),
 535                                ones);
 536                 }
 537         }
 538         else
 539 #endif
 540         if (!*addr && !*mask)
 541                 printf("any");
 542         else {
 543                 ipa.s_addr = *addr;
 544                 printf("%s", inet_ntoa(ipa));
 545                 if ((ones = countbits(*mask)) == -1) {
 546                         ipa.s_addr = *mask;
 547                         printf("/%s", inet_ntoa(ipa));
 548                 } else
 549                         printf("/%d", ones);
 550         }
 551 }
 552
 553
 554 void    printportcmp(pr, frp)
 555 int     pr;
 556 frpcmp_t        *frp;
 557 {
 558         static char *pcmp1[] = { "*", "=", "!=", "<", ">", "<=", ">=",
 559                                  "<>", "><"};
 560
 561         if (frp->frp_cmp == FR_INRANGE || frp->frp_cmp == FR_OUTRANGE)
 562                 printf(" port %d %s %d", frp->frp_port,
 563                              pcmp1[frp->frp_cmp], frp->frp_top);
 564         else
 565                 printf(" port %s %s", pcmp1[frp->frp_cmp],
 566                              portname(pr, frp->frp_port));
 567 }
 568
 569
 570 void printbuf(buf, len, zend)
 571 char *buf;
 572 int len, zend;
 573 {
 574         char *s, c;
 575         int i;
 576
 577         for (s = buf, i = len; i; i--) {
 578                 c = *s++;
 579                 if (isprint(c))
 580                         putchar(c);
 581                 else
 582                         printf("\\%03o", c);
 583                 if ((c == '\0') && zend)
 584                         break;
 585         }
 586 }
 587
 588
 589
 590 char *hostname(v, ip)
 591 int v;
 592 void *ip;
 593 {
 594 #ifdef  USE_INET6
 595         static char hostbuf[MAXHOSTNAMELEN+1];
 596 #endif
 597         struct in_addr ipa;
 598
 599         if (v == 4) {
 600                 ipa.s_addr = *(u_32_t *)ip;
 601                 return inet_ntoa(ipa);
 602         }
 603 #ifdef  USE_INET6
 604         (void) inet_ntop(AF_INET6, ip, hostbuf, sizeof(hostbuf) - 1);
 605         hostbuf[MAXHOSTNAMELEN] = '\0';
 606         return hostbuf;
 607 #else
 608         return "IPv6";
 609 #endif
 610 }