sys/netinet6/ah_output.c

   1 /*      $NetBSD: ah_output.c,v 1.32 2009/03/14 14:46:10 dsl Exp $       */
   2 /*      $KAME: ah_output.c,v 1.31 2001/07/26 06:53:15 jinmei Exp $      */
   3
   4 /*
   5  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the name of the project nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 /*
  34  * RFC1826/2402 authentication header.
  35  */
  36
  37 #include <sys/cdefs.h>
  38 __KERNEL_RCSID(0, "$NetBSD: ah_output.c,v 1.32 2009/03/14 14:46:10 dsl Exp $");
  39
  40 #include "opt_inet.h"
  41
  42 #include <sys/param.h>
  43 #include <sys/systm.h>
  44 #include <sys/malloc.h>
  45 #include <sys/mbuf.h>
  46 #include <sys/domain.h>
  47 #include <sys/protosw.h>
  48 #include <sys/socket.h>
  49 #include <sys/socketvar.h>
  50 #include <sys/errno.h>
  51 #include <sys/time.h>
  52 #include <sys/kernel.h>
  53 #include <sys/syslog.h>
  54
  55 #include <net/if.h>
  56 #include <net/route.h>
  57
  58 #include <netinet/in.h>
  59
  60 #include <netinet/in_systm.h>
  61 #include <netinet/ip.h>
  62 #include <netinet/in_var.h>
  63
  64 #ifdef INET6
  65 #include <netinet/ip6.h>
  66 #include <netinet6/ip6_var.h>
  67 #include <netinet/icmp6.h>
  68 #endif
  69
  70 #include <netinet6/ipsec.h>
  71 #include <netinet6/ipsec_private.h>
  72 #include <netinet6/ah.h>
  73 #include <netkey/key.h>
  74 #include <netkey/keydb.h>
  75
  76 #include <net/net_osdep.h>
  77
  78 #ifdef INET
  79 static struct in_addr *ah4_finaldst(struct mbuf *);
  80 #endif
  81
  82 /*
  83  * compute AH header size.
  84  * transport mode only.  for tunnel mode, we should implement
  85  * virtual interface, and control MTU/MSS by the interface MTU.
  86  */
  87 size_t
  88 ah_hdrsiz(struct ipsecrequest *isr)
  89 {
  90         const struct ah_algorithm *algo;
  91         size_t hdrsiz;
  92
  93         /* sanity check */
  94         if (isr == NULL)
  95                 panic("ah_hdrsiz: NULL was passed.");
  96
  97         if (isr->saidx.proto != IPPROTO_AH)
  98                 panic("unsupported mode passed to ah_hdrsiz");
  99
 100         if (isr->sav == NULL)
 101                 goto estimate;
 102         if (isr->sav->state != SADB_SASTATE_MATURE
 103          && isr->sav->state != SADB_SASTATE_DYING)
 104                 goto estimate;
 105
 106         /* we need transport mode AH. */
 107         algo = ah_algorithm_lookup(isr->sav->alg_auth);
 108         if (!algo)
 109                 goto estimate;
 110
 111         /*
 112          * XXX
 113          * right now we don't calcurate the padding size.  simply
 114          * treat the padding size as constant, for simplicity.
 115          *
 116          * XXX variable size padding support
 117          */
 118         hdrsiz = (((*algo->sumsiz)(isr->sav) + 3) & ~(4 - 1));
 119         if (isr->sav->flags & SADB_X_EXT_OLD)
 120                 hdrsiz += sizeof(struct ah);
 121         else
 122                 hdrsiz += sizeof(struct newah);
 123
 124         return hdrsiz;
 125
 126     estimate:
 127         /* ASSUMING:
 128          *      sizeof(struct newah) > sizeof(struct ah).
 129          *      AH_MAXSUMSIZE is multiple of 4.
 130          */
 131         return sizeof(struct newah) + AH_MAXSUMSIZE;
 132 }
 133
 134 #ifdef INET
 135 /*
 136  * Modify the packet so that it includes the authentication data.
 137  * The mbuf passed must start with IPv4 header.
 138  *
 139  * assumes that the first mbuf contains IPv4 header + option only.
 140  * the function does not modify m.
 141  */
 142 int
 143 ah4_output(struct mbuf *m, struct ipsecrequest *isr)
 144 {
 145         struct secasvar *sav = isr->sav;
 146         const struct ah_algorithm *algo;
 147         u_int32_t spi;
 148         u_char *ahdrpos;
 149         u_int8_t *ahsumpos = NULL;
 150         size_t hlen = 0;        /* IP header+option in bytes */
 151         size_t plen = 0;        /* AH payload size in bytes */
 152         size_t ahlen = 0;       /* plen + sizeof(ah) */
 153         struct ip *ip;
 154         struct in_addr dst;
 155         struct in_addr *finaldst;
 156         int error;
 157         dst.s_addr = 0;         /* XXX: GCC */
 158
 159         /* sanity checks */
 160         if ((sav->flags & SADB_X_EXT_OLD) == 0 && !sav->replay) {
 161                 ip = mtod(m, struct ip *);
 162                 ipseclog((LOG_DEBUG, "ah4_output: internal error: "
 163                         "sav->replay is null: %x->%x, SPI=%u\n",
 164                         (u_int32_t)ntohl(ip->ip_src.s_addr),
 165                         (u_int32_t)ntohl(ip->ip_dst.s_addr),
 166                         (u_int32_t)ntohl(sav->spi)));
 167                 IPSEC_STATINC(IPSEC_STAT_OUT_INVAL);
 168                 error = EINVAL;
 169                 goto fail;
 170         }
 171
 172         algo = ah_algorithm_lookup(sav->alg_auth);
 173         if (!algo) {
 174                 ipseclog((LOG_ERR, "ah4_output: unsupported algorithm: "
 175                     "SPI=%u\n", (u_int32_t)ntohl(sav->spi)));
 176                 IPSEC_STATINC(IPSEC_STAT_OUT_INVAL);
 177                 error = EINVAL;
 178                 goto fail;
 179         }
 180         spi = sav->spi;
 181
 182         /*
 183          * determine the size to grow.
 184          */
 185         if (sav->flags & SADB_X_EXT_OLD) {
 186                 /* RFC 1826 */
 187                 plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1); /* XXX pad to 8byte? */
 188                 ahlen = plen + sizeof(struct ah);
 189         } else {
 190                 /* RFC 2402 */
 191                 plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1); /* XXX pad to 8byte? */
 192                 ahlen = plen + sizeof(struct newah);
 193         }
 194
 195         /*
 196          * grow the mbuf to accommodate AH.
 197          */
 198         ip = mtod(m, struct ip *);
 199         hlen = ip->ip_hl << 2;
 200
 201         if (m->m_len != hlen)
 202                 panic("ah4_output: assumption failed (first mbuf length)");
 203         if (M_LEADINGSPACE(m->m_next) < ahlen) {
 204                 struct mbuf *n;
 205                 MGET(n, M_DONTWAIT, MT_DATA);
 206                 if (!n) {
 207                         ipseclog((LOG_DEBUG, "ENOBUFS in ah4_output %d\n",
 208                             __LINE__));
 209                         error = ENOBUFS;
 210                         goto fail;
 211                 }
 212                 n->m_len = ahlen;
 213                 n->m_next = m->m_next;
 214                 m->m_next = n;
 215                 m->m_pkthdr.len += ahlen;
 216                 ahdrpos = mtod(n, u_char *);
 217         } else {
 218                 m->m_next->m_len += ahlen;
 219                 m->m_next->m_data -= ahlen;
 220                 m->m_pkthdr.len += ahlen;
 221                 ahdrpos = mtod(m->m_next, u_char *);
 222         }
 223
 224         ip = mtod(m, struct ip *);      /* just to be sure */
 225
 226         /*
 227          * initialize AH.
 228          */
 229         if (sav->flags & SADB_X_EXT_OLD) {
 230                 struct ah *ahdr;
 231
 232                 ahdr = (struct ah *)ahdrpos;
 233                 ahsumpos = (u_char *)(ahdr + 1);
 234                 ahdr->ah_len = plen >> 2;
 235                 ahdr->ah_nxt = ip->ip_p;
 236                 ahdr->ah_reserve = htons(0);
 237                 ahdr->ah_spi = spi;
 238                 memset(ahdr + 1, 0, plen);
 239         } else {
 240                 struct newah *ahdr;
 241
 242                 ahdr = (struct newah *)ahdrpos;
 243                 ahsumpos = (u_char *)(ahdr + 1);
 244                 ahdr->ah_len = (plen >> 2) + 1; /* plus one for seq# */
 245                 ahdr->ah_nxt = ip->ip_p;
 246                 ahdr->ah_reserve = htons(0);
 247                 ahdr->ah_spi = spi;
 248                 if (sav->replay->count == ~0) {
 249                         if ((sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
 250                                 /* XXX Is it noisy ? */
 251                                 ipseclog((LOG_WARNING,
 252                                     "replay counter overflowed. %s\n",
 253                                     ipsec_logsastr(sav)));
 254                                 IPSEC_STATINC(IPSEC_STAT_OUT_INVAL);
 255                                 error = EINVAL;
 256                                 goto fail;
 257                         }
 258                 }
 259                 sav->replay->count++;
 260                 /*
 261                  * XXX sequence number must not be cycled, if the SA is
 262                  * installed by IKE daemon.
 263                  */
 264                 ahdr->ah_seq = htonl(sav->replay->count & 0xffffffff);
 265                 memset(ahdr + 1, 0, plen);
 266         }
 267
 268         /*
 269          * modify IPv4 header.
 270          */
 271         ip->ip_p = IPPROTO_AH;
 272         if (ahlen < (IP_MAXPACKET - ntohs(ip->ip_len)))
 273                 ip->ip_len = htons(ntohs(ip->ip_len) + ahlen);
 274         else {
 275                 ipseclog((LOG_ERR, "IPv4 AH output: size exceeds limit\n"));
 276                 IPSEC_STATINC(IPSEC_STAT_OUT_INVAL);
 277                 error = EMSGSIZE;
 278                 goto fail;
 279         }
 280
 281         /*
 282          * If there is source routing option, update destination field in
 283          * the IPv4 header to the final destination.
 284          * Note that we do not need to update source routing option itself
 285          * (as done in IPv4 AH processing -- see ip6_output()), since
 286          * source routing option is not part of the ICV computation.
 287          */
 288         finaldst = ah4_finaldst(m);
 289         if (finaldst) {
 290                 dst.s_addr = ip->ip_dst.s_addr;
 291                 ip->ip_dst.s_addr = finaldst->s_addr;
 292         }
 293
 294         /*
 295          * calcurate the checksum, based on security association
 296          * and the algorithm specified.
 297          */
 298         error = ah4_calccksum(m, ahsumpos, plen, algo, sav);
 299         if (error) {
 300                 ipseclog((LOG_ERR,
 301                     "error after ah4_calccksum, called from ah4_output"));
 302                 IPSEC_STATINC(IPSEC_STAT_OUT_INVAL);
 303                 goto fail;
 304         }
 305
 306         if (finaldst) {
 307                 ip = mtod(m, struct ip *);      /* just to make sure */
 308                 ip->ip_dst.s_addr = dst.s_addr;
 309         }
 310         {
 311                 uint64_t *ipss = IPSEC_STAT_GETREF();
 312                 ipss[IPSEC_STAT_OUT_SUCCESS]++;
 313                 ipss[IPSEC_STAT_OUT_AHHIST + sav->alg_auth]++;
 314                 IPSEC_STAT_PUTREF();
 315         }
 316         key_sa_recordxfer(sav, m);
 317
 318         return 0;
 319
 320 fail:
 321         m_freem(m);
 322         return error;
 323 }
 324 #endif
 325
 326 /* Calculate AH length */
 327 int
 328 ah_hdrlen(struct secasvar *sav)
 329 {
 330         const struct ah_algorithm *algo;
 331         int plen, ahlen;
 332
 333         algo = ah_algorithm_lookup(sav->alg_auth);
 334         if (!algo)
 335                 return 0;
 336         if (sav->flags & SADB_X_EXT_OLD) {
 337                 /* RFC 1826 */
 338                 plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1);   /* XXX pad to 8byte? */
 339                 ahlen = plen + sizeof(struct ah);
 340         } else {
 341                 /* RFC 2402 */
 342                 plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1);   /* XXX pad to 8byte? */
 343                 ahlen = plen + sizeof(struct newah);
 344         }
 345
 346         return (ahlen);
 347 }
 348
 349 #ifdef INET6
 350 /*
 351  * Fill in the Authentication Header and calculate checksum.
 352  */
 353 int
 354 ah6_output(struct mbuf *m, u_char *nexthdrp, struct mbuf *md,
 355         struct ipsecrequest *isr)
 356 {
 357         struct mbuf *mprev;
 358         struct mbuf *mah;
 359         struct secasvar *sav = isr->sav;
 360         const struct ah_algorithm *algo;
 361         u_int32_t spi;
 362         u_int8_t *ahsumpos = NULL;
 363         size_t plen;    /* AH payload size in bytes */
 364         int error = 0;
 365         int ahlen;
 366         struct ip6_hdr *ip6;
 367
 368         if (m->m_len < sizeof(struct ip6_hdr)) {
 369                 ipseclog((LOG_DEBUG, "ah6_output: first mbuf too short\n"));
 370                 error = EINVAL;
 371                 goto fail;
 372         }
 373
 374         ahlen = ah_hdrlen(sav);
 375         if (ahlen == 0)
 376                 return 0;
 377
 378         for (mprev = m; mprev && mprev->m_next != md; mprev = mprev->m_next)
 379                 ;
 380         if (!mprev || mprev->m_next != md) {
 381                 ipseclog((LOG_DEBUG, "ah6_output: md is not in chain\n"));
 382                 error = EINVAL;
 383                 goto fail;
 384         }
 385
 386         MGET(mah, M_DONTWAIT, MT_DATA);
 387         if (!mah) {
 388                 error = ENOBUFS;
 389                 goto fail;
 390         }
 391         if (ahlen > MLEN) {
 392                 MCLGET(mah, M_DONTWAIT);
 393                 if ((mah->m_flags & M_EXT) == 0) {
 394                         m_free(mah);
 395                         error = ENOBUFS;
 396                         goto fail;
 397                 }
 398         }
 399         mah->m_len = ahlen;
 400         mah->m_next = md;
 401         mprev->m_next = mah;
 402         m->m_pkthdr.len += ahlen;
 403
 404         /* fix plen */
 405         if (m->m_pkthdr.len - sizeof(struct ip6_hdr) > IPV6_MAXPACKET) {
 406                 ipseclog((LOG_ERR,
 407                     "ah6_output: AH with IPv6 jumbogram is not supported\n"));
 408                 error = EINVAL;
 409                 goto fail;
 410         }
 411         ip6 = mtod(m, struct ip6_hdr *);
 412         ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
 413
 414         if ((sav->flags & SADB_X_EXT_OLD) == 0 && !sav->replay) {
 415                 ipseclog((LOG_DEBUG, "ah6_output: internal error: "
 416                         "sav->replay is null: SPI=%u\n",
 417                         (u_int32_t)ntohl(sav->spi)));
 418                 IPSEC6_STATINC(IPSEC_STAT_OUT_INVAL);
 419                 error = EINVAL;
 420                 goto fail;
 421         }
 422
 423         algo = ah_algorithm_lookup(sav->alg_auth);
 424         if (!algo) {
 425                 ipseclog((LOG_ERR, "ah6_output: unsupported algorithm: "
 426                     "SPI=%u\n", (u_int32_t)ntohl(sav->spi)));
 427                 IPSEC6_STATINC(IPSEC_STAT_OUT_INVAL);
 428                 error = EINVAL;
 429                 goto fail;
 430         }
 431         spi = sav->spi;
 432
 433         /*
 434          * initialize AH.
 435          */
 436         if (sav->flags & SADB_X_EXT_OLD) {
 437                 struct ah *ahdr = mtod(mah, struct ah *);
 438
 439                 plen = mah->m_len - sizeof(struct ah);
 440                 ahsumpos = (u_char *)(ahdr + 1);
 441                 ahdr->ah_nxt = *nexthdrp;
 442                 *nexthdrp = IPPROTO_AH;
 443                 ahdr->ah_len = plen >> 2;
 444                 ahdr->ah_reserve = htons(0);
 445                 ahdr->ah_spi = spi;
 446                 memset(ahdr + 1, 0, plen);
 447         } else {
 448                 struct newah *ahdr = mtod(mah, struct newah *);
 449
 450                 plen = mah->m_len - sizeof(struct newah);
 451                 ahsumpos = (u_char *)(ahdr + 1);
 452                 ahdr->ah_nxt = *nexthdrp;
 453                 *nexthdrp = IPPROTO_AH;
 454                 ahdr->ah_len = (plen >> 2) + 1; /* plus one for seq# */
 455                 ahdr->ah_reserve = htons(0);
 456                 ahdr->ah_spi = spi;
 457                 if (sav->replay->count == ~0) {
 458                         if ((sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
 459                                 /* XXX Is it noisy ? */
 460                                 ipseclog((LOG_WARNING,
 461                                     "replay counter overflowed. %s\n",
 462                                     ipsec_logsastr(sav)));
 463                                 IPSEC6_STATINC(IPSEC_STAT_OUT_INVAL);
 464                                 error = EINVAL;
 465                                 goto fail;
 466                         }
 467                 }
 468                 sav->replay->count++;
 469                 /*
 470                  * XXX sequence number must not be cycled, if the SA is
 471                  * installed by IKE daemon.
 472                  */
 473                 ahdr->ah_seq = htonl(sav->replay->count);
 474                 memset(ahdr + 1, 0, plen);
 475         }
 476
 477         /*
 478          * calcurate the checksum, based on security association
 479          * and the algorithm specified.
 480          */
 481         error = ah6_calccksum(m, ahsumpos, plen, algo, sav);
 482         if (error) {
 483                 IPSEC6_STATINC(IPSEC_STAT_OUT_INVAL);
 484                 goto fail;
 485         } else {
 486                 IPSEC6_STATINC(IPSEC_STAT_OUT_SUCCESS);
 487                 key_sa_recordxfer(sav, m);
 488         }
 489         IPSEC6_STATINC(IPSEC_STAT_OUT_AHHIST + sav->alg_auth);
 490
 491         return 0;
 492
 493 fail:
 494         m_freem(m);
 495         return error;
 496
 497 }
 498 #endif
 499
 500 #ifdef INET
 501 /*
 502  * Find the final destination if there is loose/strict source routing option.
 503  * Returns NULL if there's no source routing options.
 504  * Returns NULL on errors too.
 505  * Note that this function will return a pointer INTO the given parameter,
 506  * struct mbuf *m.
 507  * The mbuf must be pulled up toward, at least, ip option part.
 508  */
 509 static struct in_addr *
 510 ah4_finaldst(struct mbuf *m)
 511 {
 512         struct ip *ip;
 513         int optlen;
 514         u_char *q;
 515         int i;
 516         int hlen;
 517
 518         if (!m)
 519                 panic("ah4_finaldst: m == NULL");
 520         ip = mtod(m, struct ip *);
 521         hlen = (ip->ip_hl << 2);
 522
 523         if (m->m_len < hlen) {
 524                 ipseclog((LOG_DEBUG,
 525                     "ah4_finaldst: parameter mbuf wrong (not pulled up)\n"));
 526                 return NULL;
 527         }
 528
 529         if (hlen == sizeof(struct ip))
 530                 return NULL;
 531
 532         optlen = hlen - sizeof(struct ip);
 533         if (optlen < 0) {
 534                 ipseclog((LOG_DEBUG, "ah4_finaldst: wrong optlen %d\n",
 535                     optlen));
 536                 return NULL;
 537         }
 538
 539         q = (u_char *)(ip + 1);
 540         i = 0;
 541         while (i < optlen) {
 542                 if (i + IPOPT_OPTVAL >= optlen)
 543                         return NULL;
 544                 if (q[i + IPOPT_OPTVAL] == IPOPT_EOL ||
 545                     q[i + IPOPT_OPTVAL] == IPOPT_NOP ||
 546                     i + IPOPT_OLEN < optlen)
 547                         ;
 548                 else
 549                         return NULL;
 550
 551                 switch (q[i + IPOPT_OPTVAL]) {
 552                 case IPOPT_EOL:
 553                         i = optlen;     /* bye */
 554                         break;
 555                 case IPOPT_NOP:
 556                         i++;
 557                         break;
 558                 case IPOPT_LSRR:
 559                 case IPOPT_SSRR:
 560                         if (q[i + IPOPT_OLEN] < 2 + sizeof(struct in_addr) ||
 561                             optlen - i < q[i + IPOPT_OLEN]) {
 562                                 ipseclog((LOG_ERR,
 563                                     "ip_finaldst: invalid IP option "
 564                                     "(code=%02x len=%02x)\n",
 565                                     q[i + IPOPT_OPTVAL], q[i + IPOPT_OLEN]));
 566                                 return NULL;
 567                         }
 568                         i += q[i + IPOPT_OLEN] - sizeof(struct in_addr);
 569                         return (struct in_addr *)(q + i);
 570                 default:
 571                         if (q[i + IPOPT_OLEN] < 2 ||
 572                             optlen - i < q[i + IPOPT_OLEN]) {
 573                                 ipseclog((LOG_ERR,
 574                                     "ip_finaldst: invalid IP option "
 575                                     "(code=%02x len=%02x)\n",
 576                                     q[i + IPOPT_OPTVAL], q[i + IPOPT_OLEN]));
 577                                 return NULL;
 578                         }
 579                         i += q[i + IPOPT_OLEN];
 580                         break;
 581                 }
 582         }
 583         return NULL;
 584 }
 585 #endif