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 /*      $DragonFly: src/sys/netinet6/ah_output.c,v 1.9 2006/10/24 06:18:42 hsu Exp $    */
   3 /*      $KAME: ah_output.c,v 1.31 2001/07/26 06:53:15 jinmei Exp $      */
   4
   5 /*
   6  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
   7  * All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 3. Neither the name of the project nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 /*
  35  * RFC1826/2402 authentication header.
  36  */
  37
  38 #include "opt_inet.h"
  39 #include "opt_inet6.h"
  40
  41 #include <sys/param.h>
  42 #include <sys/systm.h>
  43 #include <sys/mbuf.h>
  44 #include <sys/domain.h>
  45 #include <sys/protosw.h>
  46 #include <sys/socket.h>
  47 #include <sys/socketvar.h>
  48 #include <sys/errno.h>
  49 #include <sys/time.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 #ifdef 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 #ifdef INET6
  69 #include <netinet6/ipsec6.h>
  70 #endif
  71 #include <netinet6/ah.h>
  72 #ifdef INET6
  73 #include <netinet6/ah6.h>
  74 #endif
  75 #include <netproto/key/key.h>
  76 #include <netproto/key/keydb.h>
  77
  78 #include <net/net_osdep.h>
  79
  80 #ifdef 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(struct ipsecrequest *isr)
  91 {
  92         const struct ah_algorithm *algo;
  93         size_t hdrsiz;
  94
  95         /* sanity check */
  96         if (isr == NULL)
  97                 panic("ah_hdrsiz: NULL was passed.");
  98
  99         if (isr->saidx.proto != IPPROTO_AH)
 100                 panic("unsupported mode passed to ah_hdrsiz");
 101
 102         if (isr->sav == NULL)
 103                 goto estimate;
 104         if (isr->sav->state != SADB_SASTATE_MATURE
 105          && isr->sav->state != SADB_SASTATE_DYING)
 106                 goto estimate;
 107
 108         /* we need transport mode AH. */
 109         algo = ah_algorithm_lookup(isr->sav->alg_auth);
 110         if (!algo)
 111                 goto estimate;
 112
 113         /*
 114          * XXX
 115          * right now we don't calcurate the padding size.  simply
 116          * treat the padding size as constant, for simplicity.
 117          *
 118          * XXX variable size padding support
 119          */
 120         hdrsiz = (((*algo->sumsiz)(isr->sav) + 3) & ~(4 - 1));
 121         if (isr->sav->flags & SADB_X_EXT_OLD)
 122                 hdrsiz += sizeof(struct ah);
 123         else
 124                 hdrsiz += sizeof(struct newah);
 125
 126         return hdrsiz;
 127
 128 estimate:
 129         /* ASSUMING:
 130          *      sizeof(struct newah) > sizeof(struct ah).
 131          *      16 = (16 + 3) & ~(4 - 1).
 132          */
 133         return sizeof(struct newah) + 16;
 134 }
 135
 136 #ifdef INET
 137 /*
 138  * Modify the packet so that it includes the authentication data.
 139  * The mbuf passed must start with IPv4 header.
 140  *
 141  * assumes that the first mbuf contains IPv4 header + option only.
 142  * the function does not modify m.
 143  */
 144 int
 145 ah4_output(struct mbuf *m, struct ipsecrequest *isr)
 146 {
 147         struct secasvar *sav = isr->sav;
 148         const struct ah_algorithm *algo;
 149         u_int32_t spi;
 150         u_char *ahdrpos;
 151         u_char *ahsumpos = NULL;
 152         size_t hlen = 0;        /* IP header+option in bytes */
 153         size_t plen = 0;        /* AH payload size in bytes */
 154         size_t ahlen = 0;       /* plen + sizeof(ah) */
 155         struct ip *ip;
 156         struct in_addr dst;
 157         struct in_addr *finaldst;
 158         int error;
 159
 160         /* sanity checks */
 161         if ((sav->flags & SADB_X_EXT_OLD) == 0 && !sav->replay) {
 162                 struct ip *ip;
 163
 164                 ip = mtod(m, struct ip *);
 165                 ipseclog((LOG_DEBUG, "ah4_output: internal error: "
 166                         "sav->replay is null: %x->%x, SPI=%u\n",
 167                         (u_int32_t)ntohl(ip->ip_src.s_addr),
 168                         (u_int32_t)ntohl(ip->ip_dst.s_addr),
 169                         (u_int32_t)ntohl(sav->spi)));
 170                 ipsecstat.out_inval++;
 171                 m_freem(m);
 172                 return EINVAL;
 173         }
 174
 175         algo = ah_algorithm_lookup(sav->alg_auth);
 176         if (!algo) {
 177                 ipseclog((LOG_ERR, "ah4_output: unsupported algorithm: "
 178                     "SPI=%u\n", (u_int32_t)ntohl(sav->spi)));
 179                 ipsecstat.out_inval++;
 180                 m_freem(m);
 181                 return EINVAL;
 182         }
 183         spi = sav->spi;
 184
 185         /*
 186          * determine the size to grow.
 187          */
 188         if (sav->flags & SADB_X_EXT_OLD) {
 189                 /* RFC 1826 */
 190                 plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1); /* XXX pad to 8byte? */
 191                 ahlen = plen + sizeof(struct ah);
 192         } else {
 193                 /* RFC 2402 */
 194                 plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1); /* XXX pad to 8byte? */
 195                 ahlen = plen + sizeof(struct newah);
 196         }
 197
 198         /*
 199          * grow the mbuf to accomodate AH.
 200          */
 201         ip = mtod(m, struct ip *);
 202 #ifdef _IP_VHL
 203         hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 204 #else
 205         hlen = ip->ip_hl << 2;
 206 #endif
 207
 208         if (m->m_len != hlen)
 209                 panic("ah4_output: assumption failed (first mbuf length)");
 210         if (M_LEADINGSPACE(m->m_next) < ahlen) {
 211                 struct mbuf *n;
 212                 MGET(n, MB_DONTWAIT, MT_DATA);
 213                 if (!n) {
 214                         ipseclog((LOG_DEBUG, "ENOBUFS in ah4_output %d\n",
 215                             __LINE__));
 216                         m_freem(m);
 217                         return ENOBUFS;
 218                 }
 219                 n->m_len = ahlen;
 220                 n->m_next = m->m_next;
 221                 m->m_next = n;
 222                 m->m_pkthdr.len += ahlen;
 223                 ahdrpos = mtod(n, u_char *);
 224         } else {
 225                 m->m_next->m_len += ahlen;
 226                 m->m_next->m_data -= ahlen;
 227                 m->m_pkthdr.len += ahlen;
 228                 ahdrpos = mtod(m->m_next, u_char *);
 229         }
 230
 231         ip = mtod(m, struct ip *);      /* just to be sure */
 232
 233         /*
 234          * initialize AH.
 235          */
 236         if (sav->flags & SADB_X_EXT_OLD) {
 237                 struct ah *ahdr;
 238
 239                 ahdr = (struct ah *)ahdrpos;
 240                 ahsumpos = (u_char *)(ahdr + 1);
 241                 ahdr->ah_len = plen >> 2;
 242                 ahdr->ah_nxt = ip->ip_p;
 243                 ahdr->ah_reserve = htons(0);
 244                 ahdr->ah_spi = spi;
 245                 bzero(ahdr + 1, plen);
 246         } else {
 247                 struct newah *ahdr;
 248
 249                 ahdr = (struct newah *)ahdrpos;
 250                 ahsumpos = (u_char *)(ahdr + 1);
 251                 ahdr->ah_len = (plen >> 2) + 1; /* plus one for seq# */
 252                 ahdr->ah_nxt = ip->ip_p;
 253                 ahdr->ah_reserve = htons(0);
 254                 ahdr->ah_spi = spi;
 255                 if (sav->replay->count == ~0) {
 256                         if ((sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
 257                                 /* XXX Is it noisy ? */
 258                                 ipseclog((LOG_WARNING,
 259                                     "replay counter overflowed. %s\n",
 260                                     ipsec_logsastr(sav)));
 261                                 ipsecstat.out_inval++;
 262                                 m_freem(m);
 263                                 return EINVAL;
 264                         }
 265                 }
 266                 sav->replay->count++;
 267                 /*
 268                  * XXX sequence number must not be cycled, if the SA is
 269                  * installed by IKE daemon.
 270                  */
 271                 ahdr->ah_seq = htonl(sav->replay->count & 0xffffffff);
 272                 bzero(ahdr + 1, plen);
 273         }
 274
 275         /*
 276          * modify IPv4 header.
 277          */
 278         ip->ip_p = IPPROTO_AH;
 279         if (ahlen < (IP_MAXPACKET - ntohs(ip->ip_len)))
 280                 ip->ip_len = htons(ntohs(ip->ip_len) + ahlen);
 281         else {
 282                 ipseclog((LOG_ERR, "IPv4 AH output: size exceeds limit\n"));
 283                 ipsecstat.out_inval++;
 284                 m_freem(m);
 285                 return EMSGSIZE;
 286         }
 287
 288         /*
 289          * If there is source routing option, update destination field in
 290          * the IPv4 header to the final destination.
 291          * Note that we do not need to update source routing option itself
 292          * (as done in IPv4 AH processing -- see ip6_output()), since
 293          * source routing option is not part of the ICV computation.
 294          */
 295         finaldst = ah4_finaldst(m);
 296         if (finaldst) {
 297                 dst.s_addr = ip->ip_dst.s_addr;
 298                 ip->ip_dst.s_addr = finaldst->s_addr;
 299         } else {
 300                 dst.s_addr = 0; /* fix compiler warning */
 301         }
 302
 303         /*
 304          * calcurate the checksum, based on security association
 305          * and the algorithm specified.
 306          */
 307         error = ah4_calccksum(m, (caddr_t)ahsumpos, plen, algo, sav);
 308         if (error) {
 309                 ipseclog((LOG_ERR,
 310                     "error after ah4_calccksum, called from ah4_output"));
 311                 m_freem(m);
 312                 m = NULL;
 313                 ipsecstat.out_inval++;
 314                 return error;
 315         }
 316
 317         if (finaldst) {
 318                 ip = mtod(m, struct ip *);      /* just to make sure */
 319                 ip->ip_dst.s_addr = dst.s_addr;
 320         }
 321         ipsecstat.out_success++;
 322         ipsecstat.out_ahhist[sav->alg_auth]++;
 323         key_sa_recordxfer(sav, m);
 324
 325         return 0;
 326 }
 327 #endif
 328
 329 /* Calculate AH length */
 330 int
 331 ah_hdrlen(struct secasvar *sav)
 332 {
 333         const struct ah_algorithm *algo;
 334         int plen, ahlen;
 335
 336         algo = ah_algorithm_lookup(sav->alg_auth);
 337         if (!algo)
 338                 return 0;
 339         if (sav->flags & SADB_X_EXT_OLD) {
 340                 /* RFC 1826 */
 341                 plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1);   /* XXX pad to 8byte? */
 342                 ahlen = plen + sizeof(struct ah);
 343         } else {
 344                 /* RFC 2402 */
 345                 plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1);   /* XXX pad to 8byte? */
 346                 ahlen = plen + sizeof(struct newah);
 347         }
 348
 349         return (ahlen);
 350 }
 351
 352 #ifdef INET6
 353 /*
 354  * Fill in the Authentication Header and calculate checksum.
 355  */
 356 int
 357 ah6_output(struct mbuf *m, u_char *nexthdrp, struct mbuf *md,
 358            struct ipsecrequest *isr)
 359 {
 360         struct mbuf *mprev;
 361         struct mbuf *mah;
 362         struct secasvar *sav = isr->sav;
 363         const struct ah_algorithm *algo;
 364         u_int32_t spi;
 365         u_char *ahsumpos = NULL;
 366         size_t plen;    /* AH payload size in bytes */
 367         int error = 0;
 368         int ahlen;
 369         struct ip6_hdr *ip6;
 370
 371         if (m->m_len < sizeof(struct ip6_hdr)) {
 372                 ipseclog((LOG_DEBUG, "ah6_output: first mbuf too short\n"));
 373                 m_freem(m);
 374                 return EINVAL;
 375         }
 376
 377         ahlen = ah_hdrlen(sav);
 378         if (ahlen == 0)
 379                 return 0;
 380
 381         for (mprev = m; mprev && mprev->m_next != md; mprev = mprev->m_next)
 382                 ;
 383         if (!mprev || mprev->m_next != md) {
 384                 ipseclog((LOG_DEBUG, "ah6_output: md is not in chain\n"));
 385                 m_freem(m);
 386                 return EINVAL;
 387         }
 388
 389         mah = m_getb(ahlen, MB_DONTWAIT, MT_DATA, 0);
 390         if (mah == NULL) {
 391                 m_freem(m);
 392                 return ENOBUFS;
 393         }
 394         mah->m_len = ahlen;
 395         mah->m_next = md;
 396         mprev->m_next = mah;
 397         m->m_pkthdr.len += ahlen;
 398
 399         /* fix plen */
 400         if (m->m_pkthdr.len - sizeof(struct ip6_hdr) > IPV6_MAXPACKET) {
 401                 ipseclog((LOG_ERR,
 402                     "ah6_output: AH with IPv6 jumbogram is not supported\n"));
 403                 m_freem(m);
 404                 return EINVAL;
 405         }
 406         ip6 = mtod(m, struct ip6_hdr *);
 407         ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
 408
 409         if ((sav->flags & SADB_X_EXT_OLD) == 0 && !sav->replay) {
 410                 ipseclog((LOG_DEBUG, "ah6_output: internal error: "
 411                         "sav->replay is null: SPI=%u\n",
 412                         (u_int32_t)ntohl(sav->spi)));
 413                 ipsec6stat.out_inval++;
 414                 m_freem(m);
 415                 return EINVAL;
 416         }
 417
 418         algo = ah_algorithm_lookup(sav->alg_auth);
 419         if (!algo) {
 420                 ipseclog((LOG_ERR, "ah6_output: unsupported algorithm: "
 421                     "SPI=%u\n", (u_int32_t)ntohl(sav->spi)));
 422                 ipsec6stat.out_inval++;
 423                 m_freem(m);
 424                 return EINVAL;
 425         }
 426         spi = sav->spi;
 427
 428         /*
 429          * initialize AH.
 430          */
 431         if (sav->flags & SADB_X_EXT_OLD) {
 432                 struct ah *ahdr = mtod(mah, struct ah *);
 433
 434                 plen = mah->m_len - sizeof(struct ah);
 435                 ahsumpos = (u_char *)(ahdr + 1);
 436                 ahdr->ah_nxt = *nexthdrp;
 437                 *nexthdrp = IPPROTO_AH;
 438                 ahdr->ah_len = plen >> 2;
 439                 ahdr->ah_reserve = htons(0);
 440                 ahdr->ah_spi = spi;
 441                 bzero(ahdr + 1, plen);
 442         } else {
 443                 struct newah *ahdr = mtod(mah, struct newah *);
 444
 445                 plen = mah->m_len - sizeof(struct newah);
 446                 ahsumpos = (u_char *)(ahdr + 1);
 447                 ahdr->ah_nxt = *nexthdrp;
 448                 *nexthdrp = IPPROTO_AH;
 449                 ahdr->ah_len = (plen >> 2) + 1; /* plus one for seq# */
 450                 ahdr->ah_reserve = htons(0);
 451                 ahdr->ah_spi = spi;
 452                 if (sav->replay->count == ~0) {
 453                         if ((sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
 454                                 /* XXX Is it noisy ? */
 455                                 ipseclog((LOG_WARNING,
 456                                     "replay counter overflowed. %s\n",
 457                                     ipsec_logsastr(sav)));
 458                                 ipsec6stat.out_inval++;
 459                                 m_freem(m);
 460                                 return EINVAL;
 461                         }
 462                 }
 463                 sav->replay->count++;
 464                 /*
 465                  * XXX sequence number must not be cycled, if the SA is
 466                  * installed by IKE daemon.
 467                  */
 468                 ahdr->ah_seq = htonl(sav->replay->count);
 469                 bzero(ahdr + 1, plen);
 470         }
 471
 472         /*
 473          * calcurate the checksum, based on security association
 474          * and the algorithm specified.
 475          */
 476         error = ah6_calccksum(m, (caddr_t)ahsumpos, plen, algo, sav);
 477         if (error) {
 478                 ipsec6stat.out_inval++;
 479                 m_freem(m);
 480         } else {
 481                 ipsec6stat.out_success++;
 482                 key_sa_recordxfer(sav, m);
 483         }
 484         ipsec6stat.out_ahhist[sav->alg_auth]++;
 485
 486         return (error);
 487 }
 488 #endif
 489
 490 #ifdef INET
 491 /*
 492  * Find the final destination if there is loose/strict source routing option.
 493  * Returns NULL if there's no source routing options.
 494  * Returns NULL on errors too.
 495  * Note that this function will return a pointer INTO the given parameter,
 496  * struct mbuf *m.
 497  * The mbuf must be pulled up toward, at least, ip option part.
 498  */
 499 static struct in_addr *
 500 ah4_finaldst(struct mbuf *m)
 501 {
 502         struct ip *ip;
 503         int optlen;
 504         u_char *q;
 505         int i;
 506         int hlen;
 507
 508         if (!m)
 509                 panic("ah4_finaldst: m == NULL");
 510         ip = mtod(m, struct ip *);
 511         hlen = (ip->ip_hl << 2);
 512
 513         if (m->m_len < hlen) {
 514                 ipseclog((LOG_DEBUG,
 515                     "ah4_finaldst: parameter mbuf wrong (not pulled up)\n"));
 516                 return NULL;
 517         }
 518
 519         if (hlen == sizeof(struct ip))
 520                 return NULL;
 521
 522         optlen = hlen - sizeof(struct ip);
 523         if (optlen < 0) {
 524                 ipseclog((LOG_DEBUG, "ah4_finaldst: wrong optlen %d\n",
 525                     optlen));
 526                 return NULL;
 527         }
 528
 529         q = (u_char *)(ip + 1);
 530         i = 0;
 531         while (i < optlen) {
 532                 if (i + IPOPT_OPTVAL >= optlen)
 533                         return NULL;
 534                 if (q[i + IPOPT_OPTVAL] == IPOPT_EOL ||
 535                     q[i + IPOPT_OPTVAL] == IPOPT_NOP ||
 536                     i + IPOPT_OLEN < optlen)
 537                         ;
 538                 else
 539                         return NULL;
 540
 541                 switch (q[i + IPOPT_OPTVAL]) {
 542                 case IPOPT_EOL:
 543                         i = optlen;     /* bye */
 544                         break;
 545                 case IPOPT_NOP:
 546                         i++;
 547                         break;
 548                 case IPOPT_LSRR:
 549                 case IPOPT_SSRR:
 550                         if (q[i + IPOPT_OLEN] < 2 + sizeof(struct in_addr) ||
 551                             optlen - i < q[i + IPOPT_OLEN]) {
 552                                 ipseclog((LOG_ERR,
 553                                     "ip_finaldst: invalid IP option "
 554                                     "(code=%02x len=%02x)\n",
 555                                     q[i + IPOPT_OPTVAL], q[i + IPOPT_OLEN]));
 556                                 return NULL;
 557                         }
 558                         i += q[i + IPOPT_OLEN] - sizeof(struct in_addr);
 559                         return (struct in_addr *)(q + i);
 560                 default:
 561                         if (q[i + IPOPT_OLEN] < 2 ||
 562                             optlen - i < q[i + IPOPT_OLEN]) {
 563                                 ipseclog((LOG_ERR,
 564                                     "ip_finaldst: invalid IP option "
 565                                     "(code=%02x len=%02x)\n",
 566                                     q[i + IPOPT_OPTVAL], q[i + IPOPT_OLEN]));
 567                                 return NULL;
 568                         }
 569                         i += q[i + IPOPT_OLEN];
 570                         break;
 571                 }
 572         }
 573         return NULL;
 574 }
 575 #endif