bsd/netinet6/ah_output.c

   1 /*      $FreeBSD: src/sys/netinet6/ah_output.c,v 1.1.2.3 2001/07/03 11:01:49 ume Exp $  */
   2 /*      $KAME: ah_output.c,v 1.30 2001/02/21 00:50:53 itojun 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 #define _IP_VHL
  38
  39 #include <sys/param.h>
  40 #include <sys/systm.h>
  41 #include <sys/malloc.h>
  42 #include <sys/mbuf.h>
  43 #include <sys/domain.h>
  44 #include <sys/protosw.h>
  45 #include <sys/socket.h>
  46 #include <sys/socketvar.h>
  47 #include <sys/errno.h>
  48 #include <sys/time.h>
  49 #include <sys/kernel.h>
  50 #include <sys/syslog.h>
  51
  52 #include <net/if.h>
  53 #include <net/route.h>
  54
  55 #include <netinet/in.h>
  56
  57 #include <netinet/in_systm.h>
  58 #include <netinet/ip.h>
  59 #include <netinet/in_var.h>
  60
  61 #if INET6
  62 #include <netinet/ip6.h>
  63 #include <netinet6/ip6_var.h>
  64 #include <netinet/icmp6.h>
  65 #endif
  66
  67 #include <netinet6/ipsec.h>
  68 #if INET6
  69 #include <netinet6/ipsec6.h>
  70 #endif
  71 #include <netinet6/ah.h>
  72 #if INET6
  73 #include <netinet6/ah6.h>
  74 #endif
  75 #include <netkey/key.h>
  76 #include <netkey/keydb.h>
  77
  78 #include <net/net_osdep.h>
  79
  80 #if INET
  81 static struct in_addr *ah4_finaldst(struct mbuf *);
  82 #endif
  83
  84 /*
  85  * compute AH header size.
  86  * transport mode only.  for tunnel mode, we should implement
  87  * virtual interface, and control MTU/MSS by the interface MTU.
  88  */
  89 size_t
  90 ah_hdrsiz(isr)
  91         struct ipsecrequest *isr;
  92 {
  93         const struct ah_algorithm *algo;
  94         size_t hdrsiz;
  95
  96         /* sanity check */
  97         if (isr == NULL)
  98                 panic("ah_hdrsiz: NULL was passed.\n");
  99
 100         if (isr->saidx.proto != IPPROTO_AH)
 101                 panic("unsupported mode passed to ah_hdrsiz");
 102
 103         if (isr->sav == NULL)
 104                 goto estimate;
 105         if (isr->sav->state != SADB_SASTATE_MATURE
 106          && isr->sav->state != SADB_SASTATE_DYING)
 107                 goto estimate;
 108
 109         /* we need transport mode AH. */
 110         algo = ah_algorithm_lookup(isr->sav->alg_auth);
 111         if (!algo)
 112                 goto estimate;
 113
 114         /*
 115          * XXX
 116          * right now we don't calcurate the padding size.  simply
 117          * treat the padding size as constant, for simplicity.
 118          *
 119          * XXX variable size padding support
 120          */
 121         hdrsiz = (((*algo->sumsiz)(isr->sav) + 3) & ~(4 - 1));
 122         if (isr->sav->flags & SADB_X_EXT_OLD)
 123                 hdrsiz += sizeof(struct ah);
 124         else
 125                 hdrsiz += sizeof(struct newah);
 126
 127         return hdrsiz;
 128
 129     estimate:
 130         /* ASSUMING:
 131          *      sizeof(struct newah) > sizeof(struct ah).
 132          *      16 = (16 + 3) & ~(4 - 1).
 133          */
 134         return sizeof(struct newah) + 16;
 135 }
 136
 137 #if INET
 138 /*
 139  * Modify the packet so that it includes the authentication data.
 140  * The mbuf passed must start with IPv4 header.
 141  *
 142  * assumes that the first mbuf contains IPv4 header + option only.
 143  * the function does not modify m.
 144  */
 145 int
 146 ah4_output(m, isr)
 147         struct mbuf *m;
 148         struct ipsecrequest *isr;
 149 {
 150         struct secasvar *sav = isr->sav;
 151         const struct ah_algorithm *algo;
 152         u_int32_t spi;
 153         u_char *ahdrpos;
 154         u_char *ahsumpos = NULL;
 155         size_t hlen = 0;        /*IP header+option in bytes*/
 156         size_t plen = 0;        /*AH payload size in bytes*/
 157         size_t ahlen = 0;       /*plen + sizeof(ah)*/
 158         struct ip *ip;
 159         struct in_addr dst;
 160         struct in_addr *finaldst;
 161         int error;
 162
 163         /* sanity checks */
 164         if ((sav->flags & SADB_X_EXT_OLD) == 0 && !sav->replay) {
 165                 struct ip *ip;
 166
 167                 ip = mtod(m, struct ip *);
 168                 ipseclog((LOG_DEBUG, "ah4_output: internal error: "
 169                         "sav->replay is null: %x->%x, SPI=%u\n",
 170                         (u_int32_t)ntohl(ip->ip_src.s_addr),
 171                         (u_int32_t)ntohl(ip->ip_dst.s_addr),
 172                         (u_int32_t)ntohl(sav->spi)));
 173                 ipsecstat.out_inval++;
 174                 m_freem(m);
 175                 return EINVAL;
 176         }
 177
 178         algo = ah_algorithm_lookup(sav->alg_auth);
 179         if (!algo) {
 180                 ipseclog((LOG_ERR, "ah4_output: unsupported algorithm: "
 181                     "SPI=%u\n", (u_int32_t)ntohl(sav->spi)));
 182                 ipsecstat.out_inval++;
 183                 m_freem(m);
 184                 return EINVAL;
 185         }
 186         spi = sav->spi;
 187
 188         /*
 189          * determine the size to grow.
 190          */
 191         if (sav->flags & SADB_X_EXT_OLD) {
 192                 /* RFC 1826 */
 193                 plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1); /*XXX pad to 8byte?*/
 194                 ahlen = plen + sizeof(struct ah);
 195         } else {
 196                 /* RFC 2402 */
 197                 plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1); /*XXX pad to 8byte?*/
 198                 ahlen = plen + sizeof(struct newah);
 199         }
 200
 201         /*
 202          * grow the mbuf to accomodate AH.
 203          */
 204         ip = mtod(m, struct ip *);
 205 #ifdef _IP_VHL
 206         hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 207 #else
 208         hlen = ip->ip_hl << 2;
 209 #endif
 210
 211         if (m->m_len != hlen)
 212                 panic("ah4_output: assumption failed (first mbuf length)");
 213         if (M_LEADINGSPACE(m->m_next) < ahlen) {
 214                 struct mbuf *n;
 215                 MGET(n, M_DONTWAIT, MT_DATA);
 216                 if (!n) {
 217                         ipseclog((LOG_DEBUG, "ENOBUFS in ah4_output %d\n",
 218                             __LINE__));
 219                         m_freem(m);
 220                         return ENOBUFS;
 221                 }
 222                 n->m_len = ahlen;
 223                 n->m_next = m->m_next;
 224                 m->m_next = n;
 225                 m->m_pkthdr.len += ahlen;
 226                 ahdrpos = mtod(n, u_char *);
 227         } else {
 228                 m->m_next->m_len += ahlen;
 229                 m->m_next->m_data -= ahlen;
 230                 m->m_pkthdr.len += ahlen;
 231                 ahdrpos = mtod(m->m_next, u_char *);
 232         }
 233
 234         ip = mtod(m, struct ip *);      /*just to be sure*/
 235
 236         /*
 237          * initialize AH.
 238          */
 239         if (sav->flags & SADB_X_EXT_OLD) {
 240                 struct ah *ahdr;
 241
 242                 ahdr = (struct ah *)ahdrpos;
 243                 ahsumpos = (u_char *)(ahdr + 1);
 244                 ahdr->ah_len = plen >> 2;
 245                 ahdr->ah_nxt = ip->ip_p;
 246                 ahdr->ah_reserve = htons(0);
 247                 ahdr->ah_spi = spi;
 248                 bzero(ahdr + 1, plen);
 249         } else {
 250                 struct newah *ahdr;
 251
 252                 ahdr = (struct newah *)ahdrpos;
 253                 ahsumpos = (u_char *)(ahdr + 1);
 254                 ahdr->ah_len = (plen >> 2) + 1; /* plus one for seq# */
 255                 ahdr->ah_nxt = ip->ip_p;
 256                 ahdr->ah_reserve = htons(0);
 257                 ahdr->ah_spi = spi;
 258                 if (sav->replay->count == ~0) {
 259                         if ((sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
 260                                 /* XXX Is it noisy ? */
 261                                 ipseclog((LOG_WARNING,
 262                                     "replay counter overflowed. %s\n",
 263                                     ipsec_logsastr(sav)));
 264                                 ipsecstat.out_inval++;
 265                                 m_freem(m);
 266                                 return EINVAL;
 267                         }
 268                 }
 269                 sav->replay->count++;
 270                 /*
 271                  * XXX sequence number must not be cycled, if the SA is
 272                  * installed by IKE daemon.
 273                  */
 274                 ahdr->ah_seq = htonl(sav->replay->count);
 275                 bzero(ahdr + 1, plen);
 276         }
 277
 278         /*
 279          * modify IPv4 header.
 280          */
 281         ip->ip_p = IPPROTO_AH;
 282         if (ahlen < (IP_MAXPACKET - ntohs(ip->ip_len)))
 283                 ip->ip_len = htons(ntohs(ip->ip_len) + ahlen);
 284         else {
 285                 ipseclog((LOG_ERR, "IPv4 AH output: size exceeds limit\n"));
 286                 ipsecstat.out_inval++;
 287                 m_freem(m);
 288                 return EMSGSIZE;
 289         }
 290
 291         /*
 292          * If there is source routing option, update destination field in
 293          * the IPv4 header to the final destination.
 294          * Note that we do not need to update source routing option itself
 295          * (as done in IPv4 AH processing -- see ip6_output()), since
 296          * source routing option is not part of the ICV computation.
 297          */
 298         finaldst = ah4_finaldst(m);
 299         if (finaldst) {
 300                 dst.s_addr = ip->ip_dst.s_addr;
 301                 ip->ip_dst.s_addr = finaldst->s_addr;
 302         }
 303
 304         /*
 305          * calcurate the checksum, based on security association
 306          * and the algorithm specified.
 307          */
 308         error = ah4_calccksum(m, (caddr_t)ahsumpos, plen, algo, sav);
 309         if (error) {
 310                 ipseclog((LOG_ERR,
 311                     "error after ah4_calccksum, called from ah4_output"));
 312                 m_freem(m);
 313                 m = NULL;
 314                 ipsecstat.out_inval++;
 315                 return error;
 316         }
 317
 318         if (finaldst) {
 319                 ip = mtod(m, struct ip *);      /*just to make sure*/
 320                 ip->ip_dst.s_addr = dst.s_addr;
 321         }
 322         ipsecstat.out_success++;
 323         ipsecstat.out_ahhist[sav->alg_auth]++;
 324         key_sa_recordxfer(sav, m);
 325
 326         return 0;
 327 }
 328 #endif
 329
 330 /* Calculate AH length */
 331 int
 332 ah_hdrlen(sav)
 333         struct secasvar *sav;
 334 {
 335         const struct ah_algorithm *algo;
 336         int plen, ahlen;
 337
 338         algo = ah_algorithm_lookup(sav->alg_auth);
 339         if (!algo)
 340                 return 0;
 341         if (sav->flags & SADB_X_EXT_OLD) {
 342                 /* RFC 1826 */
 343                 plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1);   /*XXX pad to 8byte?*/
 344                 ahlen = plen + sizeof(struct ah);
 345         } else {
 346                 /* RFC 2402 */
 347                 plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1);   /*XXX pad to 8byte?*/
 348                 ahlen = plen + sizeof(struct newah);
 349         }
 350
 351         return(ahlen);
 352 }
 353
 354 #if INET6
 355 /*
 356  * Fill in the Authentication Header and calculate checksum.
 357  */
 358 int
 359 ah6_output(m, nexthdrp, md, isr)
 360         struct mbuf *m;
 361         u_char *nexthdrp;
 362         struct mbuf *md;
 363         struct ipsecrequest *isr;
 364 {
 365         struct mbuf *mprev;
 366         struct mbuf *mah;
 367         struct secasvar *sav = isr->sav;
 368         const struct ah_algorithm *algo;
 369         u_int32_t spi;
 370         u_char *ahsumpos = NULL;
 371         size_t plen;    /*AH payload size in bytes*/
 372         int error = 0;
 373         int ahlen;
 374         struct ip6_hdr *ip6;
 375
 376         if (m->m_len < sizeof(struct ip6_hdr)) {
 377                 ipseclog((LOG_DEBUG, "ah6_output: first mbuf too short\n"));
 378                 m_freem(m);
 379                 return EINVAL;
 380         }
 381
 382         ahlen = ah_hdrlen(sav);
 383         if (ahlen == 0)
 384                 return 0;
 385
 386         for (mprev = m; mprev && mprev->m_next != md; mprev = mprev->m_next)
 387                 ;
 388         if (!mprev || mprev->m_next != md) {
 389                 ipseclog((LOG_DEBUG, "ah6_output: md is not in chain\n"));
 390                 m_freem(m);
 391                 return EINVAL;
 392         }
 393
 394         MGET(mah, M_DONTWAIT, MT_DATA);
 395         if (!mah) {
 396                 m_freem(m);
 397                 return ENOBUFS;
 398         }
 399         if (ahlen > MLEN) {
 400                 MCLGET(mah, M_DONTWAIT);
 401                 if ((mah->m_flags & M_EXT) == 0) {
 402                         m_free(mah);
 403                         m_freem(m);
 404                         return ENOBUFS;
 405                 }
 406         }
 407         mah->m_len = ahlen;
 408         mah->m_next = md;
 409         mprev->m_next = mah;
 410         m->m_pkthdr.len += ahlen;
 411
 412         /* fix plen */
 413         if (m->m_pkthdr.len - sizeof(struct ip6_hdr) > IPV6_MAXPACKET) {
 414                 ipseclog((LOG_ERR,
 415                     "ip6_output: AH with IPv6 jumbogram is not supported\n"));
 416                 m_freem(m);
 417                 return EINVAL;
 418         }
 419         ip6 = mtod(m, struct ip6_hdr *);
 420         ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
 421
 422         if ((sav->flags & SADB_X_EXT_OLD) == 0 && !sav->replay) {
 423                 ipseclog((LOG_DEBUG, "ah6_output: internal error: "
 424                         "sav->replay is null: SPI=%u\n",
 425                         (u_int32_t)ntohl(sav->spi)));
 426                 ipsec6stat.out_inval++;
 427                 m_freem(m);
 428                 return EINVAL;
 429         }
 430
 431         algo = ah_algorithm_lookup(sav->alg_auth);
 432         if (!algo) {
 433                 ipseclog((LOG_ERR, "ah6_output: unsupported algorithm: "
 434                     "SPI=%u\n", (u_int32_t)ntohl(sav->spi)));
 435                 ipsec6stat.out_inval++;
 436                 m_freem(m);
 437                 return EINVAL;
 438         }
 439         spi = sav->spi;
 440
 441         /*
 442          * initialize AH.
 443          */
 444         if (sav->flags & SADB_X_EXT_OLD) {
 445                 struct ah *ahdr = mtod(mah, struct ah *);
 446
 447                 plen = mah->m_len - sizeof(struct ah);
 448                 ahsumpos = (u_char *)(ahdr + 1);
 449                 ahdr->ah_nxt = *nexthdrp;
 450                 *nexthdrp = IPPROTO_AH;
 451                 ahdr->ah_len = plen >> 2;
 452                 ahdr->ah_reserve = htons(0);
 453                 ahdr->ah_spi = spi;
 454                 bzero(ahdr + 1, plen);
 455         } else {
 456                 struct newah *ahdr = mtod(mah, struct newah *);
 457
 458                 plen = mah->m_len - sizeof(struct newah);
 459                 ahsumpos = (u_char *)(ahdr + 1);
 460                 ahdr->ah_nxt = *nexthdrp;
 461                 *nexthdrp = IPPROTO_AH;
 462                 ahdr->ah_len = (plen >> 2) + 1; /* plus one for seq# */
 463                 ahdr->ah_reserve = htons(0);
 464                 ahdr->ah_spi = spi;
 465                 if (sav->replay->count == ~0) {
 466                         if ((sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
 467                                 /* XXX Is it noisy ? */
 468                                 ipseclog((LOG_WARNING,
 469                                     "replay counter overflowed. %s\n",
 470                                     ipsec_logsastr(sav)));
 471                                 ipsec6stat.out_inval++;
 472                                 m_freem(m);
 473                                 return EINVAL;
 474                         }
 475                 }
 476                 sav->replay->count++;
 477                 /*
 478                  * XXX sequence number must not be cycled, if the SA is
 479                  * installed by IKE daemon.
 480                  */
 481                 ahdr->ah_seq = htonl(sav->replay->count);
 482                 bzero(ahdr + 1, plen);
 483         }
 484
 485         /*
 486          * calcurate the checksum, based on security association
 487          * and the algorithm specified.
 488          */
 489         error = ah6_calccksum(m, (caddr_t)ahsumpos, plen, algo, sav);
 490         if (error) {
 491                 ipsec6stat.out_inval++;
 492                 m_freem(m);
 493         } else {
 494                 ipsec6stat.out_success++;
 495                 key_sa_recordxfer(sav, m);
 496         }
 497         ipsec6stat.out_ahhist[sav->alg_auth]++;
 498
 499         return(error);
 500 }
 501 #endif
 502
 503 #if INET
 504 /*
 505  * Find the final destination if there is loose/strict source routing option.
 506  * Returns NULL if there's no source routing options.
 507  * Returns NULL on errors too.
 508  * Note that this function will return a pointer INTO the given parameter,
 509  * struct mbuf *m.
 510  * The mbuf must be pulled up toward, at least, ip option part.
 511  */
 512 static struct in_addr *
 513 ah4_finaldst(m)
 514         struct mbuf *m;
 515 {
 516         struct ip *ip;
 517         int optlen;
 518         u_char *q;
 519         int i;
 520         int hlen;
 521
 522         if (!m)
 523                 panic("ah4_finaldst: m == NULL");
 524         ip = mtod(m, struct ip *);
 525 #ifdef _IP_VHL
 526         hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 527 #else
 528         hlen = ip->ip_hl << 2;
 529 #endif
 530
 531         if (m->m_len < hlen) {
 532                 ipseclog((LOG_DEBUG,
 533                     "ah4_finaldst: parameter mbuf wrong (not pulled up)\n"));
 534                 return NULL;
 535         }
 536
 537         if (hlen == sizeof(struct ip))
 538                 return NULL;
 539
 540         optlen = hlen - sizeof(struct ip);
 541         if (optlen < 0) {
 542                 ipseclog((LOG_DEBUG, "ah4_finaldst: wrong optlen %d\n",
 543                     optlen));
 544                 return NULL;
 545         }
 546
 547         q = (u_char *)(ip + 1);
 548         i = 0;
 549         while (i < optlen) {
 550                 if (i + IPOPT_OPTVAL >= optlen)
 551                         return NULL;
 552                 if (q[i + IPOPT_OPTVAL] == IPOPT_EOL ||
 553                     q[i + IPOPT_OPTVAL] == IPOPT_NOP ||
 554                     i + IPOPT_OLEN < optlen)
 555                         ;
 556                 else
 557                         return NULL;
 558
 559                 switch (q[i + IPOPT_OPTVAL]) {
 560                 case IPOPT_EOL:
 561                         i = optlen;     /* bye */
 562                         break;
 563                 case IPOPT_NOP:
 564                         i++;
 565                         break;
 566                 case IPOPT_LSRR:
 567                 case IPOPT_SSRR:
 568                         if (q[i + IPOPT_OLEN] < 2 + sizeof(struct in_addr) ||
 569                             optlen - i < q[i + IPOPT_OLEN]) {
 570                                 ipseclog((LOG_ERR,
 571                                     "ip_finaldst: invalid IP option "
 572                                     "(code=%02x len=%02x)\n",
 573                                     q[i + IPOPT_OPTVAL], q[i + IPOPT_OLEN]));
 574                                 return NULL;
 575                         }
 576                         i += q[i + IPOPT_OLEN] - sizeof(struct in_addr);
 577                         return (struct in_addr *)(q + i);
 578                 default:
 579                         if (q[i + IPOPT_OLEN] < 2 ||
 580                             optlen - i < q[i + IPOPT_OLEN]) {
 581                                 ipseclog((LOG_ERR,
 582                                     "ip_finaldst: invalid IP option "
 583                                     "(code=%02x len=%02x)\n",
 584                                     q[i + IPOPT_OPTVAL], q[i + IPOPT_OLEN]));
 585                                 return NULL;
 586                         }
 587                         i += q[i + IPOPT_OLEN];
 588                         break;
 589                 }
 590         }
 591         return NULL;
 592 }
 593 #endif