contrib/ipfilter/ip_auth.c

   1 /*
   2  * Copyright (C) 1998-2001 by Darren Reed & Guido van Rooij.
   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/errno.h>
  10 #include <sys/types.h>
  11 #include <sys/param.h>
  12 #include <sys/time.h>
  13 #include <sys/file.h>
  14 #if !defined(_KERNEL) && !defined(KERNEL)
  15 # include <stdio.h>
  16 # include <stdlib.h>
  17 # include <string.h>
  18 #endif
  19 #if (defined(KERNEL) || defined(_KERNEL)) && (__FreeBSD_version >= 220000)
  20 # include <sys/filio.h>
  21 # include <sys/fcntl.h>
  22 #else
  23 # include <sys/ioctl.h>
  24 #endif
  25 #ifndef linux
  26 # include <sys/protosw.h>
  27 #endif
  28 #include <sys/socket.h>
  29 #if (defined(_KERNEL) || defined(KERNEL)) && !defined(linux)
  30 # include <sys/systm.h>
  31 #endif
  32 #if !defined(__SVR4) && !defined(__svr4__)
  33 # ifndef linux
  34 #  include <sys/mbuf.h>
  35 # endif
  36 #else
  37 # include <sys/filio.h>
  38 # include <sys/byteorder.h>
  39 # ifdef _KERNEL
  40 #  include <sys/dditypes.h>
  41 # endif
  42 # include <sys/stream.h>
  43 # include <sys/kmem.h>
  44 #endif
  45 #if (_BSDI_VERSION >= 199802) || (__FreeBSD_version >= 400000)
  46 # include <sys/queue.h>
  47 #endif
  48 #if defined(__NetBSD__) || defined(__OpenBSD__) || defined(bsdi)
  49 # include <machine/cpu.h>
  50 #endif
  51 #include <net/if.h>
  52 #ifdef sun
  53 # include <net/af.h>
  54 #endif
  55 #include <net/route.h>
  56 #include <netinet/in.h>
  57 #include <netinet/in_systm.h>
  58 #include <netinet/ip.h>
  59 #ifndef KERNEL
  60 # define        KERNEL
  61 # define        NOT_KERNEL
  62 #endif
  63 #ifndef linux
  64 # include <netinet/ip_var.h>
  65 #endif
  66 #ifdef  NOT_KERNEL
  67 # undef KERNEL
  68 #endif
  69 #ifdef __sgi
  70 # ifdef IFF_DRVRLOCK /* IRIX6 */
  71 #  include <sys/hashing.h>
  72 # endif
  73 #endif
  74 #include <netinet/tcp.h>
  75 #if defined(__sgi) && !defined(IFF_DRVRLOCK) /* IRIX < 6 */
  76 extern struct ifqueue   ipintrq;                /* ip packet input queue */
  77 #else
  78 # ifndef linux
  79 #  if __FreeBSD_version >= 300000
  80 #   include <net/if_var.h>
  81 #  endif
  82 #  include <netinet/in_var.h>
  83 #  include <netinet/tcp_fsm.h>
  84 # endif
  85 #endif
  86 #include <netinet/udp.h>
  87 #include <netinet/ip_icmp.h>
  88 #include "netinet/ip_compat.h"
  89 #include <netinet/tcpip.h>
  90 #include "netinet/ip_fil.h"
  91 #include "netinet/ip_auth.h"
  92 #if !SOLARIS && !defined(linux)
  93 # include <net/netisr.h>
  94 # ifdef __FreeBSD__
  95 #  include <machine/cpufunc.h>
  96 # endif
  97 #endif
  98 #if (__FreeBSD_version >= 300000)
  99 # include <sys/malloc.h>
 100 # if (defined(_KERNEL) || defined(KERNEL)) && !defined(IPFILTER_LKM)
 101 #  include <sys/libkern.h>
 102 #  include <sys/systm.h>
 103 # endif
 104 #endif
 105
 106 #if !defined(lint)
 107 static const char rcsid[] = "@(#)$Id: ip_auth.c,v 2.11.2.24 2002/12/06 11:40:21 darrenr Exp $";
 108 #endif
 109
 110
 111 #if (SOLARIS || defined(__sgi)) && defined(_KERNEL)
 112 extern KRWLOCK_T ipf_auth, ipf_mutex;
 113 extern kmutex_t ipf_authmx;
 114 # if SOLARIS
 115 extern kcondvar_t ipfauthwait;
 116 # endif
 117 #endif
 118 #ifdef linux
 119 static struct wait_queue *ipfauthwait = NULL;
 120 #endif
 121
 122 int     fr_authsize = FR_NUMAUTH;
 123 int     fr_authused = 0;
 124 int     fr_defaultauthage = 600;
 125 int     fr_auth_lock = 0;
 126 fr_authstat_t   fr_authstats;
 127 static frauth_t fr_auth[FR_NUMAUTH];
 128 mb_t    *fr_authpkts[FR_NUMAUTH];
 129 static int      fr_authstart = 0, fr_authend = 0, fr_authnext = 0;
 130 static frauthent_t      *fae_list = NULL;
 131 frentry_t       *ipauth = NULL,
 132                 *fr_authlist = NULL;
 133
 134
 135 /*
 136  * Check if a packet has authorization.  If the packet is found to match an
 137  * authorization result and that would result in a feedback loop (i.e. it
 138  * will end up returning FR_AUTH) then return FR_BLOCK instead.
 139  */
 140 u_32_t fr_checkauth(ip, fin)
 141 ip_t *ip;
 142 fr_info_t *fin;
 143 {
 144         u_short id = ip->ip_id;
 145         frentry_t *fr;
 146         frauth_t *fra;
 147         u_32_t pass;
 148         int i;
 149
 150         if (fr_auth_lock || !fr_authused)
 151                 return 0;
 152
 153         READ_ENTER(&ipf_auth);
 154         for (i = fr_authstart; i != fr_authend; ) {
 155                 /*
 156                  * index becomes -2 only after an SIOCAUTHW.  Check this in
 157                  * case the same packet gets sent again and it hasn't yet been
 158                  * auth'd.
 159                  */
 160                 fra = fr_auth + i;
 161                 if ((fra->fra_index == -2) && (id == fra->fra_info.fin_id) &&
 162                     !bcmp((char *)fin, (char *)&fra->fra_info, FI_CSIZE)) {
 163                         /*
 164                          * Avoid feedback loop.
 165                          */
 166                         if (!(pass = fra->fra_pass) || (pass & FR_AUTH))
 167                                 pass = FR_BLOCK;
 168                         /*
 169                          * Create a dummy rule for the stateful checking to
 170                          * use and return.  Zero out any values we don't
 171                          * trust from userland!
 172                          */
 173                         if ((pass & FR_KEEPSTATE) || ((pass & FR_KEEPFRAG) &&
 174                              (fin->fin_fi.fi_fl & FI_FRAG))) {
 175                                 KMALLOC(fr, frentry_t *);
 176                                 if (fr) {
 177                                         bcopy((char *)fra->fra_info.fin_fr,
 178                                               fr, sizeof(*fr));
 179                                         fr->fr_grp = NULL;
 180                                         fr->fr_ifa = fin->fin_ifp;
 181                                         fr->fr_func = NULL;
 182                                         fr->fr_ref = 1;
 183                                         fr->fr_flags = pass;
 184 #if BSD >= 199306
 185                                         fr->fr_oifa = NULL;
 186 #endif
 187                                 }
 188                         } else
 189                                 fr = fra->fra_info.fin_fr;
 190                         fin->fin_fr = fr;
 191                         RWLOCK_EXIT(&ipf_auth);
 192                         WRITE_ENTER(&ipf_auth);
 193                         if (fr && fr != fra->fra_info.fin_fr) {
 194                                 fr->fr_next = fr_authlist;
 195                                 fr_authlist = fr;
 196                         }
 197                         fr_authstats.fas_hits++;
 198                         fra->fra_index = -1;
 199                         fr_authused--;
 200                         if (i == fr_authstart) {
 201                                 while (fra->fra_index == -1) {
 202                                         i++;
 203                                         fra++;
 204                                         if (i == FR_NUMAUTH) {
 205                                                 i = 0;
 206                                                 fra = fr_auth;
 207                                         }
 208                                         fr_authstart = i;
 209                                         if (i == fr_authend)
 210                                                 break;
 211                                 }
 212                                 if (fr_authstart == fr_authend) {
 213                                         fr_authnext = 0;
 214                                         fr_authstart = fr_authend = 0;
 215                                 }
 216                         }
 217                         RWLOCK_EXIT(&ipf_auth);
 218                         return pass;
 219                 }
 220                 i++;
 221                 if (i == FR_NUMAUTH)
 222                         i = 0;
 223         }
 224         fr_authstats.fas_miss++;
 225         RWLOCK_EXIT(&ipf_auth);
 226         return 0;
 227 }
 228
 229
 230 /*
 231  * Check if we have room in the auth array to hold details for another packet.
 232  * If we do, store it and wake up any user programs which are waiting to
 233  * hear about these events.
 234  */
 235 int fr_newauth(m, fin, ip)
 236 mb_t *m;
 237 fr_info_t *fin;
 238 ip_t *ip;
 239 {
 240 #if defined(_KERNEL) && SOLARIS
 241         qif_t *qif = fin->fin_qif;
 242 #endif
 243         frauth_t *fra;
 244         int i;
 245
 246         if (fr_auth_lock)
 247                 return 0;
 248
 249         WRITE_ENTER(&ipf_auth);
 250         if (fr_authstart > fr_authend) {
 251                 fr_authstats.fas_nospace++;
 252                 RWLOCK_EXIT(&ipf_auth);
 253                 return 0;
 254         } else {
 255                 if (fr_authused == FR_NUMAUTH) {
 256                         fr_authstats.fas_nospace++;
 257                         RWLOCK_EXIT(&ipf_auth);
 258                         return 0;
 259                 }
 260         }
 261
 262         fr_authstats.fas_added++;
 263         fr_authused++;
 264         i = fr_authend++;
 265         if (fr_authend == FR_NUMAUTH)
 266                 fr_authend = 0;
 267         RWLOCK_EXIT(&ipf_auth);
 268         fra = fr_auth + i;
 269         fra->fra_index = i;
 270         fra->fra_pass = 0;
 271         fra->fra_age = fr_defaultauthage;
 272         bcopy((char *)fin, (char *)&fra->fra_info, sizeof(*fin));
 273 #if SOLARIS && defined(_KERNEL)
 274 # if !defined(sparc)
 275         /*
 276          * No need to copyback here as we want to undo the changes, not keep
 277          * them.
 278          */
 279         if ((ip == (ip_t *)m->b_rptr) && (ip->ip_v == 4))
 280         {
 281                 register u_short bo;
 282
 283                 bo = ip->ip_len;
 284                 ip->ip_len = htons(bo);
 285                 bo = ip->ip_off;
 286                 ip->ip_off = htons(bo);
 287         }
 288 # endif
 289         m->b_rptr -= qif->qf_off;
 290         fr_authpkts[i] = *(mblk_t **)fin->fin_mp;
 291         fra->fra_q = qif->qf_q;
 292         cv_signal(&ipfauthwait);
 293 #else
 294 # if defined(BSD) && !defined(sparc) && (BSD >= 199306)
 295         if (fin->fin_out == 0) {
 296                 ip->ip_len = htons(ip->ip_len);
 297                 ip->ip_off = htons(ip->ip_off);
 298         }
 299 # endif
 300         fr_authpkts[i] = m;
 301         WAKEUP(&fr_authnext);
 302 #endif
 303         return 1;
 304 }
 305
 306
 307 int fr_auth_ioctl(data, mode, cmd)
 308 caddr_t data;
 309 int mode;
 310 #if defined(__NetBSD__) || defined(__OpenBSD__) || (__FreeBSD_version >= 300003)
 311 u_long cmd;
 312 #else
 313 int cmd;
 314 #endif
 315 {
 316         mb_t *m;
 317 #if defined(_KERNEL) && !SOLARIS
 318         struct ifqueue *ifq;
 319         int s;
 320 #endif
 321         frauth_t auth, *au = &auth, *fra;
 322         int i, error = 0;
 323
 324         switch (cmd)
 325         {
 326         case SIOCSTLCK :
 327                 if (!(mode & FWRITE)) {
 328                         error = EPERM;
 329                         break;
 330                 }
 331                 error = fr_lock(data, &fr_auth_lock);
 332                 break;
 333         case SIOCINIFR :
 334         case SIOCRMIFR :
 335         case SIOCADIFR :
 336                 error = EINVAL;
 337                 break;
 338         case SIOCINAFR :
 339                 error = EINVAL;
 340                 break;
 341         case SIOCRMAFR :
 342         case SIOCADAFR :
 343                 /* These commands go via request to fr_preauthcmd */
 344                 error = EINVAL;
 345                 break;
 346         case SIOCATHST:
 347                 fr_authstats.fas_faelist = fae_list;
 348                 error = IWCOPYPTR((char *)&fr_authstats, data,
 349                                    sizeof(fr_authstats));
 350                 break;
 351         case SIOCAUTHW:
 352                 if (!(mode & FWRITE)) {
 353                         error = EPERM;
 354                         break;
 355                 }
 356 fr_authioctlloop:
 357                 READ_ENTER(&ipf_auth);
 358                 if ((fr_authnext != fr_authend) && fr_authpkts[fr_authnext]) {
 359                         error = IWCOPYPTR((char *)&fr_auth[fr_authnext], data,
 360                                           sizeof(frauth_t));
 361                         RWLOCK_EXIT(&ipf_auth);
 362                         if (error)
 363                                 break;
 364                         WRITE_ENTER(&ipf_auth);
 365                         SPL_NET(s);
 366                         fr_authnext++;
 367                         if (fr_authnext == FR_NUMAUTH)
 368                                 fr_authnext = 0;
 369                         SPL_X(s);
 370                         RWLOCK_EXIT(&ipf_auth);
 371                         return 0;
 372                 }
 373                 RWLOCK_EXIT(&ipf_auth);
 374 #ifdef  _KERNEL
 375 # if    SOLARIS
 376                 mutex_enter(&ipf_authmx);
 377                 if (!cv_wait_sig(&ipfauthwait, &ipf_authmx)) {
 378                         mutex_exit(&ipf_authmx);
 379                         return EINTR;
 380                 }
 381                 mutex_exit(&ipf_authmx);
 382 # else
 383                 error = SLEEP(&fr_authnext, "fr_authnext");
 384 # endif
 385 #endif
 386                 if (!error)
 387                         goto fr_authioctlloop;
 388                 break;
 389         case SIOCAUTHR:
 390                 if (!(mode & FWRITE)) {
 391                         error = EPERM;
 392                         break;
 393                 }
 394                 error = IRCOPYPTR(data, (caddr_t)&auth, sizeof(auth));
 395                 if (error)
 396                         return error;
 397                 WRITE_ENTER(&ipf_auth);
 398                 SPL_NET(s);
 399                 i = au->fra_index;
 400                 fra = fr_auth + i;
 401                 if ((i < 0) || (i > FR_NUMAUTH) ||
 402                     (fra->fra_info.fin_id != au->fra_info.fin_id)) {
 403                         SPL_X(s);
 404                         RWLOCK_EXIT(&ipf_auth);
 405                         return EINVAL;
 406                 }
 407                 m = fr_authpkts[i];
 408                 fra->fra_index = -2;
 409                 fra->fra_pass = au->fra_pass;
 410                 fr_authpkts[i] = NULL;
 411                 RWLOCK_EXIT(&ipf_auth);
 412 #ifdef  _KERNEL
 413                 if (m && au->fra_info.fin_out) {
 414 # if SOLARIS
 415                         error = (fr_qout(fra->fra_q, m) == 0) ? EINVAL : 0;
 416 # else /* SOLARIS */
 417                         struct route ro;
 418
 419                         bzero((char *)&ro, sizeof(ro));
 420 #  if ((_BSDI_VERSION >= 199802) && (_BSDI_VERSION < 200005)) || \
 421        defined(__OpenBSD__) || (defined(IRIX) && (IRIX >= 605))
 422                         error = ip_output(m, NULL, &ro, IP_FORWARDING, NULL,
 423                                           NULL);
 424 #  else
 425                         error = ip_output(m, NULL, &ro, IP_FORWARDING, NULL);
 426 #  endif
 427                         if (ro.ro_rt) {
 428                                 RTFREE(ro.ro_rt);
 429                         }
 430 # endif /* SOLARIS */
 431                         if (error)
 432                                 fr_authstats.fas_sendfail++;
 433                         else
 434                                 fr_authstats.fas_sendok++;
 435                 } else if (m) {
 436 # if SOLARIS
 437                         error = (fr_qin(fra->fra_q, m) == 0) ? EINVAL : 0;
 438 # else /* SOLARIS */
 439                         ifq = &ipintrq;
 440                         if (IF_QFULL(ifq)) {
 441                                 IF_DROP(ifq);
 442                                 m_freem(m);
 443                                 error = ENOBUFS;
 444                         } else {
 445                                 IF_ENQUEUE(ifq, m);
 446 #  if IRIX < 605
 447                                 schednetisr(NETISR_IP);
 448 #  endif
 449                         }
 450 # endif /* SOLARIS */
 451                         if (error)
 452                                 fr_authstats.fas_quefail++;
 453                         else
 454                                 fr_authstats.fas_queok++;
 455                 } else
 456                         error = EINVAL;
 457 # if SOLARIS
 458                 if (error)
 459                         error = EINVAL;
 460 # else
 461                 /*
 462                  * If we experience an error which will result in the packet
 463                  * not being processed, make sure we advance to the next one.
 464                  */
 465                 if (error == ENOBUFS) {
 466                         fr_authused--;
 467                         fra->fra_index = -1;
 468                         fra->fra_pass = 0;
 469                         if (i == fr_authstart) {
 470                                 while (fra->fra_index == -1) {
 471                                         i++;
 472                                         if (i == FR_NUMAUTH)
 473                                                 i = 0;
 474                                         fr_authstart = i;
 475                                         if (i == fr_authend)
 476                                                 break;
 477                                 }
 478                                 if (fr_authstart == fr_authend) {
 479                                         fr_authnext = 0;
 480                                         fr_authstart = fr_authend = 0;
 481                                 }
 482                         }
 483                 }
 484 # endif
 485 #endif /* _KERNEL */
 486                 SPL_X(s);
 487                 break;
 488         default :
 489                 error = EINVAL;
 490                 break;
 491         }
 492         return error;
 493 }
 494
 495
 496 /*
 497  * Free all network buffer memory used to keep saved packets.
 498  */
 499 void fr_authunload()
 500 {
 501         register int i;
 502         register frauthent_t *fae, **faep;
 503         frentry_t *fr, **frp;
 504         mb_t *m;
 505
 506         WRITE_ENTER(&ipf_auth);
 507         for (i = 0; i < FR_NUMAUTH; i++) {
 508                 if ((m = fr_authpkts[i])) {
 509                         FREE_MB_T(m);
 510                         fr_authpkts[i] = NULL;
 511                         fr_auth[i].fra_index = -1;
 512                 }
 513         }
 514
 515
 516         for (faep = &fae_list; (fae = *faep); ) {
 517                 *faep = fae->fae_next;
 518                 KFREE(fae);
 519         }
 520         ipauth = NULL;
 521         RWLOCK_EXIT(&ipf_auth);
 522
 523         if (fr_authlist) {
 524                 /*
 525                  * We *MuST* reget ipf_auth because otherwise we won't get the
 526                  * locks in the right order and risk deadlock.
 527                  * We need ipf_mutex here to prevent a rule from using it
 528                  * inside fr_check().
 529                  */
 530                 WRITE_ENTER(&ipf_mutex);
 531                 WRITE_ENTER(&ipf_auth);
 532                 for (frp = &fr_authlist; (fr = *frp); ) {
 533                         if (fr->fr_ref == 1) {
 534                                 *frp = fr->fr_next;
 535                                 KFREE(fr);
 536                         } else
 537                                 frp = &fr->fr_next;
 538                 }
 539                 RWLOCK_EXIT(&ipf_auth);
 540                 RWLOCK_EXIT(&ipf_mutex);
 541         }
 542 }
 543
 544
 545 /*
 546  * Slowly expire held auth records.  Timeouts are set
 547  * in expectation of this being called twice per second.
 548  */
 549 void fr_authexpire()
 550 {
 551         register int i;
 552         register frauth_t *fra;
 553         register frauthent_t *fae, **faep;
 554         register frentry_t *fr, **frp;
 555         mb_t *m;
 556 #if !SOLARIS && defined(_KERNEL)
 557         int s;
 558 #endif
 559
 560         if (fr_auth_lock)
 561                 return;
 562
 563         SPL_NET(s);
 564         WRITE_ENTER(&ipf_auth);
 565         for (i = 0, fra = fr_auth; i < FR_NUMAUTH; i++, fra++) {
 566                 if ((!--fra->fra_age) && (m = fr_authpkts[i])) {
 567                         FREE_MB_T(m);
 568                         fr_authpkts[i] = NULL;
 569                         fr_auth[i].fra_index = -1;
 570                         fr_authstats.fas_expire++;
 571                         fr_authused--;
 572                 }
 573         }
 574
 575         for (faep = &fae_list; (fae = *faep); ) {
 576                 if (!--fae->fae_age) {
 577                         *faep = fae->fae_next;
 578                         KFREE(fae);
 579                         fr_authstats.fas_expire++;
 580                 } else
 581                         faep = &fae->fae_next;
 582         }
 583         if (fae_list != NULL)
 584                 ipauth = &fae_list->fae_fr;
 585         else
 586                 ipauth = NULL;
 587
 588         for (frp = &fr_authlist; (fr = *frp); ) {
 589                 if (fr->fr_ref == 1) {
 590                         *frp = fr->fr_next;
 591                         KFREE(fr);
 592                 } else
 593                         frp = &fr->fr_next;
 594         }
 595         RWLOCK_EXIT(&ipf_auth);
 596         SPL_X(s);
 597 }
 598
 599 int fr_preauthcmd(cmd, fr, frptr)
 600 #if defined(__NetBSD__) || defined(__OpenBSD__) || \
 601         (_BSDI_VERSION >= 199701) || (__FreeBSD_version >= 300000)
 602 u_long cmd;
 603 #else
 604 int cmd;
 605 #endif
 606 frentry_t *fr, **frptr;
 607 {
 608         frauthent_t *fae, **faep;
 609         int error = 0;
 610 #if defined(KERNEL) && !SOLARIS
 611         int s;
 612 #endif
 613
 614         if ((cmd != SIOCADAFR) && (cmd != SIOCRMAFR)) {
 615                 /* Should not happen */
 616                 printf("fr_preauthcmd called with bad cmd 0x%lx", (u_long)cmd);
 617                 return EIO;
 618         }
 619
 620         for (faep = &fae_list; (fae = *faep); )
 621                 if (&fae->fae_fr == fr)
 622                         break;
 623                 else
 624                         faep = &fae->fae_next;
 625         if (cmd == SIOCRMAFR) {
 626                 if (!fr || !frptr)
 627                         error = EINVAL;
 628                 else if (!fae)
 629                         error = ESRCH;
 630                 else {
 631                         WRITE_ENTER(&ipf_auth);
 632                         SPL_NET(s);
 633                         *faep = fae->fae_next;
 634                         *frptr = fr->fr_next;
 635                         SPL_X(s);
 636                         RWLOCK_EXIT(&ipf_auth);
 637                         KFREE(fae);
 638                 }
 639         } else if (fr && frptr) {
 640                 KMALLOC(fae, frauthent_t *);
 641                 if (fae != NULL) {
 642                         bcopy((char *)fr, (char *)&fae->fae_fr,
 643                               sizeof(*fr));
 644                         WRITE_ENTER(&ipf_auth);
 645                         SPL_NET(s);
 646                         fae->fae_age = fr_defaultauthage;
 647                         fae->fae_fr.fr_hits = 0;
 648                         fae->fae_fr.fr_next = *frptr;
 649                         *frptr = &fae->fae_fr;
 650                         fae->fae_next = *faep;
 651                         *faep = fae;
 652                         ipauth = &fae_list->fae_fr;
 653                         SPL_X(s);
 654                         RWLOCK_EXIT(&ipf_auth);
 655                 } else
 656                         error = ENOMEM;
 657         } else
 658                 error = EINVAL;
 659         return error;
 660 }