sys/netinet6/ah_output.c

   1 /*      $FreeBSD: src/sys/netinet6/ah_output.c,v 1.1.2.5 2003/05/06 06:46:58 suz 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 "opt_inet.h"
  38 #include "opt_inet6.h"
  39
  40 #include <sys/param.h>
  41 #include <sys/systm.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/syslog.h>
  50
  51 #include <net/if.h>
  52 #include <net/route.h>
  53
  54 #include <netinet/in.h>
  55
  56 #include <netinet/in_systm.h>
  57 #include <netinet/ip.h>
  58 #include <netinet/in_var.h>
  59
  60 #ifdef INET6
  61 #include <netinet/ip6.h>
  62 #include <netinet6/ip6_var.h>
  63 #include <netinet/icmp6.h>
  64 #endif
  65
  66 #include <netinet6/ipsec.h>
  67 #ifdef INET6
  68 #include <netinet6/ipsec6.h>
  69 #endif
  70 #include <netinet6/ah.h>
  71 #ifdef INET6
  72 #include <netinet6/ah6.h>
  73 #endif
  74 #include <netproto/key/key.h>
  75 #include <netproto/key/keydb.h>
  76
  77 #include <net/net_osdep.h>
  78
  79 #ifdef INET
  80 static struct in_addr *ah4_finaldst (struct mbuf *);
  81 #endif
  82
  83 /*
  84  * compute AH header size.
  85  * transport mode only.  for tunnel mode, we should implement
  86  * virtual interface, and control MTU/MSS by the interface MTU.
  87  */
  88 size_t
  89 ah_hdrsiz(struct ipsecrequest *isr)
  90 {
  91         const struct ah_algorithm *algo;
  92         size_t hdrsiz;
  93
  94         /* sanity check */
  95         if (isr == NULL)
  96                 panic("ah_hdrsiz: NULL was passed.");
  97
  98         if (isr->saidx.proto != IPPROTO_AH)
  99                 panic("unsupported mode passed to ah_hdrsiz");
 100
 101         if (isr->sav == NULL)
 102                 goto estimate;
 103         if (isr->sav->state != SADB_SASTATE_MATURE
 104          && isr->sav->state != SADB_SASTATE_DYING)
 105                 goto estimate;
 106
 107         /* we need transport mode AH. */
 108         algo = ah_algorithm_lookup(isr->sav->alg_auth);
 109         if (!algo)
 110                 goto estimate;
 111
 112         /*
 113          * XXX
 114          * right now we don't calcurate the padding size.  simply
 115          * treat the padding size as constant, for simplicity.
 116          *
 117          * XXX variable size padding support
 118          */
 119         hdrsiz = (((*algo->sumsiz)(isr->sav) + 3) & ~(4 - 1));
 120         if (isr->sav->flags & SADB_X_EXT_OLD)
 121                 hdrsiz += sizeof(struct ah);
 122         else
 123                 hdrsiz += sizeof(struct newah);
 124
 125         return hdrsiz;
 126
 127 estimate:
 128         /* ASSUMING:
 129          *      sizeof(struct newah) > sizeof(struct ah).
 130          *      16 = (16 + 3) & ~(4 - 1).
 131          */
 132         return sizeof(struct newah) + 16;
 133 }
 134
 135 #ifdef INET
 136 /*
 137  * Modify the packet so that it includes the authentication data.
 138  * The mbuf passed must start with IPv4 header.
 139  *
 140  * assumes that the first mbuf contains IPv4 header + option only.
 141  * the function does not modify m.
 142  */
 143 int
 144 ah4_output(struct mbuf *m, struct ipsecrequest *isr)
 145 {
 146         struct secasvar *sav = isr->sav;
 147         const struct ah_algorithm *algo;
 148         u_int32_t spi;
 149         u_char *ahdrpos;
 150         u_char *ahsumpos = NULL;
 151         size_t hlen = 0;        /* IP header+option in bytes */
 152         size_t plen = 0;        /* AH payload size in bytes */
 153         size_t ahlen = 0;       /* plen + sizeof(ah) */
 154         struct ip *ip;
 155         struct in_addr dst;
 156         struct in_addr *finaldst;
 157         int error;
 158
 159         /* sanity checks */
 160         if ((sav->flags & SADB_X_EXT_OLD) == 0 && !sav->replay) {
 161                 struct ip *ip;
 162
 163                 ip = mtod(m, struct ip *);
 164                 ipseclog((LOG_DEBUG, "ah4_output: internal error: "
 165                         "sav->replay is null: %x->%x, SPI=%u\n",
 166                         (u_int32_t)ntohl(ip->ip_src.s_addr),
 167                         (u_int32_t)ntohl(ip->ip_dst.s_addr),
 168                         (u_int32_t)ntohl(sav->spi)));
 169                 ipsecstat.out_inval++;
 170                 m_freem(m);
 171                 return EINVAL;
 172         }
 173
 174         algo = ah_algorithm_lookup(sav->alg_auth);
 175         if (!algo) {
 176                 ipseclog((LOG_ERR, "ah4_output: unsupported algorithm: "
 177                     "SPI=%u\n", (u_int32_t)ntohl(sav->spi)));
 178                 ipsecstat.out_inval++;
 179                 m_freem(m);
 180                 return EINVAL;
 181         }
 182         spi = sav->spi;
 183
 184         /*
 185          * determine the size to grow.
 186          */
 187         if (sav->flags & SADB_X_EXT_OLD) {
 188                 /* RFC 1826 */
 189                 plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1); /* XXX pad to 8byte? */
 190                 ahlen = plen + sizeof(struct ah);
 191         } else {
 192                 /* RFC 2402 */
 193                 plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1); /* XXX pad to 8byte? */
 194                 ahlen = plen + sizeof(struct newah);
 195         }
 196
 197         /*
 198          * grow the mbuf to accomodate AH.
 199          */
 200         ip = mtod(m, struct ip *);
 201 #ifdef _IP_VHL
 202         hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 203 #else
 204         hlen = ip->ip_hl << 2;
 205 #endif
 206
 207         if (m->m_len != hlen)
 208                 panic("ah4_output: assumption failed (first mbuf length)");
 209         if (M_LEADINGSPACE(m->m_next) < ahlen) {
 210                 struct mbuf *n;
 211                 MGET(n, M_NOWAIT, MT_DATA);
 212                 if (!n) {
 213                         ipseclog((LOG_DEBUG, "ENOBUFS in ah4_output %d\n",
 214                             __LINE__));
 215                         m_freem(m);
 216                         return ENOBUFS;
 217                 }
 218                 n->m_len = ahlen;
 219                 n->m_next = m->m_next;
 220                 m->m_next = n;
 221                 m->m_pkthdr.len += ahlen;
 222                 ahdrpos = mtod(n, u_char *);
 223         } else {
 224                 m->m_next->m_len += ahlen;
 225                 m->m_next->m_data -= ahlen;
 226                 m->m_pkthdr.len += ahlen;
 227                 ahdrpos = mtod(m->m_next, u_char *);
 228         }
 229
 230         ip = mtod(m, struct ip *);      /* just to be sure */
 231
 232         /*
 233          * initialize AH.
 234          */
 235         if (sav->flags & SADB_X_EXT_OLD) {
 236                 struct ah *ahdr;
 237
 238                 ahdr = (struct ah *)ahdrpos;
 239                 ahsumpos = (u_char *)(ahdr + 1);
 240                 ahdr->ah_len = plen >> 2;
 241                 ahdr->ah_nxt = ip->ip_p;
 242                 ahdr->ah_reserve = htons(0);
 243                 ahdr->ah_spi = spi;
 244                 bzero(ahdr + 1, plen);
 245         } else {
 246                 struct newah *ahdr;
 247
 248                 ahdr = (struct newah *)ahdrpos;
 249                 ahsumpos = (u_char *)(ahdr + 1);
 250                 ahdr->ah_len = (plen >> 2) + 1; /* plus one for seq# */
 251                 ahdr->ah_nxt = ip->ip_p;
 252                 ahdr->ah_reserve = htons(0);
 253                 ahdr->ah_spi = spi;
 254                 if (sav->replay->count == ~0) {
 255                         if ((sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
 256                                 /* XXX Is it noisy ? */
 257                                 ipseclog((LOG_WARNING,
 258                                     "replay counter overflowed. %s\n",
 259                                     ipsec_logsastr(sav)));
 260                                 ipsecstat.out_inval++;
 261                                 m_freem(m);
 262                                 return EINVAL;
 263                         }
 264                 }
 265                 sav->replay->count++;
 266                 /*
 267                  * XXX sequence number must not be cycled, if the SA is
 268                  * installed by IKE daemon.
 269                  */
 270                 ahdr->ah_seq = htonl(sav->replay->count & 0xffffffff);
 271                 bzero(ahdr + 1, plen);
 272         }
 273
 274         /*
 275          * modify IPv4 header.
 276          */
 277         ip->ip_p = IPPROTO_AH;
 278         if (ahlen < (IP_MAXPACKET - ntohs(ip->ip_len)))
 279                 ip->ip_len = htons(ntohs(ip->ip_len) + ahlen);
 280         else {
 281                 ipseclog((LOG_ERR, "IPv4 AH output: size exceeds limit\n"));
 282                 ipsecstat.out_inval++;
 283                 m_freem(m);
 284                 return EMSGSIZE;
 285         }
 286
 287         /*
 288          * If there is source routing option, update destination field in
 289          * the IPv4 header to the final destination.
 290          * Note that we do not need to update source routing option itself
 291          * (as done in IPv4 AH processing -- see ip6_output()), since
 292          * source routing option is not part of the ICV computation.
 293          */
 294         finaldst = ah4_finaldst(m);
 295         if (finaldst) {
 296                 dst.s_addr = ip->ip_dst.s_addr;
 297                 ip->ip_dst.s_addr = finaldst->s_addr;
 298         } else {
 299                 dst.s_addr = 0; /* fix compiler warning */
 300         }
 301
 302         /*
 303          * calcurate the checksum, based on security association
 304          * and the algorithm specified.
 305          */
 306         error = ah4_calccksum(m, (caddr_t)ahsumpos, plen, algo, sav);
 307         if (error) {
 308                 ipseclog((LOG_ERR,
 309                     "error after ah4_calccksum, called from ah4_output"));
 310                 m_freem(m);
 311                 m = NULL;
 312                 ipsecstat.out_inval++;
 313                 return error;
 314         }
 315
 316         if (finaldst) {
 317                 ip = mtod(m, struct ip *);      /* just to make sure */
 318                 ip->ip_dst.s_addr = dst.s_addr;
 319         }
 320         ipsecstat.out_success++;
 321         ipsecstat.out_ahhist[sav->alg_auth]++;
 322         key_sa_recordxfer(sav, m);
 323
 324         return 0;
 325 }
 326 #endif
 327
 328 /* Calculate AH length */
 329 int
 330 ah_hdrlen(struct secasvar *sav)
 331 {
 332         const struct ah_algorithm *algo;
 333         int plen, ahlen;
 334
 335         algo = ah_algorithm_lookup(sav->alg_auth);
 336         if (!algo)
 337                 return 0;
 338         if (sav->flags & SADB_X_EXT_OLD) {
 339                 /* RFC 1826 */
 340                 plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1);   /* XXX pad to 8byte? */
 341                 ahlen = plen + sizeof(struct ah);
 342         } else {
 343                 /* RFC 2402 */
 344                 plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1);   /* XXX pad to 8byte? */
 345                 ahlen = plen + sizeof(struct newah);
 346         }
 347
 348         return (ahlen);
 349 }
 350
 351 #ifdef INET6
 352 /*
 353  * Fill in the Authentication Header and calculate checksum.
 354  */
 355 int
 356 ah6_output(struct mbuf *m, u_char *nexthdrp, struct mbuf *md,
 357            struct ipsecrequest *isr)
 358 {
 359         struct mbuf *mprev;
 360         struct mbuf *mah;
 361         struct secasvar *sav = isr->sav;
 362         const struct ah_algorithm *algo;
 363         u_int32_t spi;
 364         u_char *ahsumpos = NULL;
 365         size_t plen;    /* AH payload size in bytes */
 366         int error = 0;
 367         int ahlen;
 368         struct ip6_hdr *ip6;
 369
 370         if (m->m_len < sizeof(struct ip6_hdr)) {
 371                 ipseclog((LOG_DEBUG, "ah6_output: first mbuf too short\n"));
 372                 m_freem(m);
 373                 return EINVAL;
 374         }
 375
 376         ahlen = ah_hdrlen(sav);
 377         if (ahlen == 0)
 378                 return 0;
 379
 380         for (mprev = m; mprev && mprev->m_next != md; mprev = mprev->m_next)
 381                 ;
 382         if (!mprev || mprev->m_next != md) {
 383                 ipseclog((LOG_DEBUG, "ah6_output: md is not in chain\n"));
 384                 m_freem(m);
 385                 return EINVAL;
 386         }
 387
 388         mah = m_getb(ahlen, M_NOWAIT, MT_DATA, 0);
 389         if (mah == NULL) {
 390                 m_freem(m);
 391                 return ENOBUFS;
 392         }
 393         mah->m_len = ahlen;
 394         mah->m_next = md;
 395         mprev->m_next = mah;
 396         m->m_pkthdr.len += ahlen;
 397
 398         /* fix plen */
 399         if (m->m_pkthdr.len - sizeof(struct ip6_hdr) > IPV6_MAXPACKET) {
 400                 ipseclog((LOG_ERR,
 401                     "ah6_output: AH with IPv6 jumbogram is not supported\n"));
 402                 m_freem(m);
 403                 return EINVAL;
 404         }
 405         ip6 = mtod(m, struct ip6_hdr *);
 406         ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
 407
 408         if ((sav->flags & SADB_X_EXT_OLD) == 0 && !sav->replay) {
 409                 ipseclog((LOG_DEBUG, "ah6_output: internal error: "
 410                         "sav->replay is null: SPI=%u\n",
 411                         (u_int32_t)ntohl(sav->spi)));
 412                 ipsec6stat.out_inval++;
 413                 m_freem(m);
 414                 return EINVAL;
 415         }
 416
 417         algo = ah_algorithm_lookup(sav->alg_auth);
 418         if (!algo) {
 419                 ipseclog((LOG_ERR, "ah6_output: unsupported algorithm: "
 420                     "SPI=%u\n", (u_int32_t)ntohl(sav->spi)));
 421                 ipsec6stat.out_inval++;
 422                 m_freem(m);
 423                 return EINVAL;
 424         }
 425         spi = sav->spi;
 426
 427         /*
 428          * initialize AH.
 429          */
 430         if (sav->flags & SADB_X_EXT_OLD) {
 431                 struct ah *ahdr = mtod(mah, struct ah *);
 432
 433                 plen = mah->m_len - sizeof(struct ah);
 434                 ahsumpos = (u_char *)(ahdr + 1);
 435                 ahdr->ah_nxt = *nexthdrp;
 436                 *nexthdrp = IPPROTO_AH;
 437                 ahdr->ah_len = plen >> 2;
 438                 ahdr->ah_reserve = htons(0);
 439                 ahdr->ah_spi = spi;
 440                 bzero(ahdr + 1, plen);
 441         } else {
 442                 struct newah *ahdr = mtod(mah, struct newah *);
 443
 444                 plen = mah->m_len - sizeof(struct newah);
 445                 ahsumpos = (u_char *)(ahdr + 1);
 446                 ahdr->ah_nxt = *nexthdrp;
 447                 *nexthdrp = IPPROTO_AH;
 448                 ahdr->ah_len = (plen >> 2) + 1; /* plus one for seq# */
 449                 ahdr->ah_reserve = htons(0);
 450                 ahdr->ah_spi = spi;
 451                 if (sav->replay->count == ~0) {
 452                         if ((sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
 453                                 /* XXX Is it noisy ? */
 454                                 ipseclog((LOG_WARNING,
 455                                     "replay counter overflowed. %s\n",
 456                                     ipsec_logsastr(sav)));
 457                                 ipsec6stat.out_inval++;
 458                                 m_freem(m);
 459                                 return EINVAL;
 460                         }
 461                 }
 462                 sav->replay->count++;
 463                 /*
 464                  * XXX sequence number must not be cycled, if the SA is
 465                  * installed by IKE daemon.
 466                  */
 467                 ahdr->ah_seq = htonl(sav->replay->count);
 468                 bzero(ahdr + 1, plen);
 469         }
 470
 471         /*
 472          * calcurate the checksum, based on security association
 473          * and the algorithm specified.
 474          */
 475         error = ah6_calccksum(m, (caddr_t)ahsumpos, plen, algo, sav);
 476         if (error) {
 477                 ipsec6stat.out_inval++;
 478                 m_freem(m);
 479         } else {
 480                 ipsec6stat.out_success++;
 481                 key_sa_recordxfer(sav, m);
 482         }
 483         ipsec6stat.out_ahhist[sav->alg_auth]++;
 484
 485         return (error);
 486 }
 487 #endif
 488
 489 #ifdef INET
 490 /*
 491  * Find the final destination if there is loose/strict source routing option.
 492  * Returns NULL if there's no source routing options.
 493  * Returns NULL on errors too.
 494  * Note that this function will return a pointer INTO the given parameter,
 495  * struct mbuf *m.
 496  * The mbuf must be pulled up toward, at least, ip option part.
 497  */
 498 static struct in_addr *
 499 ah4_finaldst(struct mbuf *m)
 500 {
 501         struct ip *ip;
 502         int optlen;
 503         u_char *q;
 504         int i;
 505         int hlen;
 506
 507         if (!m)
 508                 panic("ah4_finaldst: m == NULL");
 509         ip = mtod(m, struct ip *);
 510         hlen = (ip->ip_hl << 2);
 511
 512         if (m->m_len < hlen) {
 513                 ipseclog((LOG_DEBUG,
 514                     "ah4_finaldst: parameter mbuf wrong (not pulled up)\n"));
 515                 return NULL;
 516         }
 517
 518         if (hlen == sizeof(struct ip))
 519                 return NULL;
 520
 521         optlen = hlen - sizeof(struct ip);
 522         if (optlen < 0) {
 523                 ipseclog((LOG_DEBUG, "ah4_finaldst: wrong optlen %d\n",
 524                     optlen));
 525                 return NULL;
 526         }
 527
 528         q = (u_char *)(ip + 1);
 529         i = 0;
 530         while (i < optlen) {
 531                 if (i + IPOPT_OPTVAL >= optlen)
 532                         return NULL;
 533                 if (q[i + IPOPT_OPTVAL] == IPOPT_EOL ||
 534                     q[i + IPOPT_OPTVAL] == IPOPT_NOP ||
 535                     i + IPOPT_OLEN < optlen)
 536                         ;
 537                 else
 538                         return NULL;
 539
 540                 switch (q[i + IPOPT_OPTVAL]) {
 541                 case IPOPT_EOL:
 542                         i = optlen;     /* bye */
 543                         break;
 544                 case IPOPT_NOP:
 545                         i++;
 546                         break;
 547                 case IPOPT_LSRR:
 548                 case IPOPT_SSRR:
 549                         if (q[i + IPOPT_OLEN] < 2 + sizeof(struct in_addr) ||
 550                             optlen - i < q[i + IPOPT_OLEN]) {
 551                                 ipseclog((LOG_ERR,
 552                                     "ip_finaldst: invalid IP option "
 553                                     "(code=%02x len=%02x)\n",
 554                                     q[i + IPOPT_OPTVAL], q[i + IPOPT_OLEN]));
 555                                 return NULL;
 556                         }
 557                         i += q[i + IPOPT_OLEN] - sizeof(struct in_addr);
 558                         return (struct in_addr *)(q + i);
 559                 default:
 560                         if (q[i + IPOPT_OLEN] < 2 ||
 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];
 569                         break;
 570                 }
 571         }
 572         return NULL;
 573 }
 574 #endif