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 extern lck_mtx_t *sadb_mutex;
  85
  86 /*
  87  * compute AH header size.
  88  * transport mode only.  for tunnel mode, we should implement
  89  * virtual interface, and control MTU/MSS by the interface MTU.
  90  */
  91 size_t
  92 ah_hdrsiz(isr)
  93         struct ipsecrequest *isr;
  94 {
  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 0
 104         {
 105
 106                 lck_mtx_lock(sadb_mutex);
 107                 const struct ah_algorithm *algo;
 108                 size_t hdrsiz;
 109
 110                 /*%%%%% this needs to change - no sav in ipsecrequest any more */
 111                 if (isr->sav == NULL)
 112                         goto estimate;
 113                 if (isr->sav->state != SADB_SASTATE_MATURE
 114                  && isr->sav->state != SADB_SASTATE_DYING)
 115                         goto estimate;
 116
 117                 /* we need transport mode AH. */
 118                 algo = ah_algorithm_lookup(isr->sav->alg_auth);
 119                 if (!algo)
 120                         goto estimate;
 121
 122                 /*
 123                  * XXX
 124                  * right now we don't calcurate the padding size.  simply
 125                  * treat the padding size as constant, for simplicity.
 126                  *
 127                  * XXX variable size padding support
 128                  */
 129                 hdrsiz = (((*algo->sumsiz)(isr->sav) + 3) & ~(4 - 1));
 130                 if (isr->sav->flags & SADB_X_EXT_OLD)
 131                         hdrsiz += sizeof(struct ah);
 132                 else
 133                         hdrsiz += sizeof(struct newah);
 134
 135                 lck_mtx_unlock(sadb_mutex);
 136                 return hdrsiz;
 137         }
 138
 139 estimate:
 140 #endif
 141
 142     //lck_mtx_unlock(sadb_mutex);
 143         /* ASSUMING:
 144          *      sizeof(struct newah) > sizeof(struct ah).
 145          *      16 = (16 + 3) & ~(4 - 1).
 146          */
 147         return sizeof(struct newah) + 16;
 148 }
 149
 150 #if INET
 151 /*
 152  * Modify the packet so that it includes the authentication data.
 153  * The mbuf passed must start with IPv4 header.
 154  *
 155  * assumes that the first mbuf contains IPv4 header + option only.
 156  * the function does not modify m.
 157  */
 158 int
 159 ah4_output(m, sav)
 160         struct mbuf *m;
 161         struct secasvar *sav;
 162 {
 163         const struct ah_algorithm *algo;
 164         u_int32_t spi;
 165         u_char *ahdrpos;
 166         u_char *ahsumpos = NULL;
 167         size_t hlen = 0;        /*IP header+option in bytes*/
 168         size_t plen = 0;        /*AH payload size in bytes*/
 169         size_t ahlen = 0;       /*plen + sizeof(ah)*/
 170         struct ip *ip;
 171         struct in_addr dst = { 0 };
 172         struct in_addr *finaldst;
 173         int error;
 174
 175         /* sanity checks */
 176         if ((sav->flags & SADB_X_EXT_OLD) == 0 && !sav->replay) {
 177                 ip = mtod(m, struct ip *);
 178                 ipseclog((LOG_DEBUG, "ah4_output: internal error: "
 179                         "sav->replay is null: %x->%x, SPI=%u\n",
 180                         (u_int32_t)ntohl(ip->ip_src.s_addr),
 181                         (u_int32_t)ntohl(ip->ip_dst.s_addr),
 182                         (u_int32_t)ntohl(sav->spi)));
 183                 IPSEC_STAT_INCREMENT(ipsecstat.out_inval);
 184                 m_freem(m);
 185                 return EINVAL;
 186         }
 187
 188         algo = ah_algorithm_lookup(sav->alg_auth);
 189         if (!algo) {
 190                 ipseclog((LOG_ERR, "ah4_output: unsupported algorithm: "
 191                     "SPI=%u\n", (u_int32_t)ntohl(sav->spi)));
 192                 IPSEC_STAT_INCREMENT(ipsecstat.out_inval);
 193                 m_freem(m);
 194                 return EINVAL;
 195         }
 196         spi = sav->spi;
 197
 198         /*
 199          * determine the size to grow.
 200          */
 201         if (sav->flags & SADB_X_EXT_OLD) {
 202                 /* RFC 1826 */
 203                 plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1); /*XXX pad to 8byte?*/
 204                 ahlen = plen + sizeof(struct ah);
 205         } else {
 206                 /* RFC 2402 */
 207                 plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1); /*XXX pad to 8byte?*/
 208                 ahlen = plen + sizeof(struct newah);
 209         }
 210
 211         /*
 212          * grow the mbuf to accomodate AH.
 213          */
 214         ip = mtod(m, struct ip *);
 215 #ifdef _IP_VHL
 216         hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 217 #else
 218         hlen = ip->ip_hl << 2;
 219 #endif
 220
 221         if (m->m_len != hlen)
 222                 panic("ah4_output: assumption failed (first mbuf length)");
 223         if (M_LEADINGSPACE(m->m_next) < ahlen) {
 224                 struct mbuf *n;
 225                 MGET(n, M_DONTWAIT, MT_DATA);
 226                 if (!n) {
 227                         ipseclog((LOG_DEBUG, "ENOBUFS in ah4_output %d\n",
 228                             __LINE__));
 229                         m_freem(m);
 230                         return ENOBUFS;
 231                 }
 232                 n->m_len = ahlen;
 233                 n->m_next = m->m_next;
 234                 m->m_next = n;
 235                 m->m_pkthdr.len += ahlen;
 236                 ahdrpos = mtod(n, u_char *);
 237         } else {
 238                 m->m_next->m_len += ahlen;
 239                 m->m_next->m_data -= ahlen;
 240                 m->m_pkthdr.len += ahlen;
 241                 ahdrpos = mtod(m->m_next, u_char *);
 242         }
 243
 244         ip = mtod(m, struct ip *);      /*just to be sure*/
 245
 246         /*
 247          * initialize AH.
 248          */
 249         if (sav->flags & SADB_X_EXT_OLD) {
 250                 struct ah *ahdr;
 251
 252                 ahdr = (struct ah *)ahdrpos;
 253                 ahsumpos = (u_char *)(ahdr + 1);
 254                 ahdr->ah_len = plen >> 2;
 255                 ahdr->ah_nxt = ip->ip_p;
 256                 ahdr->ah_reserve = htons(0);
 257                 ahdr->ah_spi = spi;
 258                 bzero(ahdr + 1, plen);
 259         } else {
 260                 struct newah *ahdr;
 261
 262                 ahdr = (struct newah *)ahdrpos;
 263                 ahsumpos = (u_char *)(ahdr + 1);
 264                 ahdr->ah_len = (plen >> 2) + 1; /* plus one for seq# */
 265                 ahdr->ah_nxt = ip->ip_p;
 266                 ahdr->ah_reserve = htons(0);
 267                 ahdr->ah_spi = spi;
 268                 if (sav->replay->count == ~0) {
 269                         if ((sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
 270                                 /* XXX Is it noisy ? */
 271                                 ipseclog((LOG_WARNING,
 272                                     "replay counter overflowed. %s\n",
 273                                     ipsec_logsastr(sav)));
 274                                 IPSEC_STAT_INCREMENT(ipsecstat.out_inval);
 275                                 m_freem(m);
 276                                 return EINVAL;
 277                         }
 278                 }
 279                 lck_mtx_lock(sadb_mutex);
 280                 sav->replay->count++;
 281                 lck_mtx_unlock(sadb_mutex);
 282                 /*
 283                  * XXX sequence number must not be cycled, if the SA is
 284                  * installed by IKE daemon.
 285                  */
 286                 ahdr->ah_seq = htonl(sav->replay->count);
 287                 bzero(ahdr + 1, plen);
 288         }
 289
 290         /*
 291          * modify IPv4 header.
 292          */
 293         ip->ip_p = IPPROTO_AH;
 294         if (ahlen < (IP_MAXPACKET - ntohs(ip->ip_len)))
 295                 ip->ip_len = htons(ntohs(ip->ip_len) + ahlen);
 296         else {
 297                 ipseclog((LOG_ERR, "IPv4 AH output: size exceeds limit\n"));
 298                 IPSEC_STAT_INCREMENT(ipsecstat.out_inval);
 299                 m_freem(m);
 300                 return EMSGSIZE;
 301         }
 302
 303         /*
 304          * If there is source routing option, update destination field in
 305          * the IPv4 header to the final destination.
 306          * Note that we do not need to update source routing option itself
 307          * (as done in IPv4 AH processing -- see ip6_output()), since
 308          * source routing option is not part of the ICV computation.
 309          */
 310         finaldst = ah4_finaldst(m);
 311         if (finaldst) {
 312                 dst.s_addr = ip->ip_dst.s_addr;
 313                 ip->ip_dst.s_addr = finaldst->s_addr;
 314         }
 315
 316         /*
 317          * calcurate the checksum, based on security association
 318          * and the algorithm specified.
 319          */
 320         error = ah4_calccksum(m, (caddr_t)ahsumpos, plen, algo, sav);
 321         if (error) {
 322                 ipseclog((LOG_ERR,
 323                     "error after ah4_calccksum, called from ah4_output"));
 324                 m_freem(m);
 325                 m = NULL;
 326                 IPSEC_STAT_INCREMENT(ipsecstat.out_inval);
 327                 return error;
 328         }
 329
 330         if (finaldst) {
 331                 ip = mtod(m, struct ip *);      /*just to make sure*/
 332                 ip->ip_dst.s_addr = dst.s_addr;
 333         }
 334         lck_mtx_lock(sadb_stat_mutex);
 335         ipsecstat.out_success++;
 336         ipsecstat.out_ahhist[sav->alg_auth]++;
 337         lck_mtx_unlock(sadb_stat_mutex);
 338         key_sa_recordxfer(sav, m);
 339
 340         return 0;
 341 }
 342 #endif
 343
 344 /* Calculate AH length */
 345 int
 346 ah_hdrlen(sav)
 347         struct secasvar *sav;
 348 {
 349         const struct ah_algorithm *algo;
 350         int plen, ahlen;
 351
 352         algo = ah_algorithm_lookup(sav->alg_auth);
 353         if (!algo)
 354                 return 0;
 355         if (sav->flags & SADB_X_EXT_OLD) {
 356                 /* RFC 1826 */
 357                 plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1);   /*XXX pad to 8byte?*/
 358                 ahlen = plen + sizeof(struct ah);
 359         } else {
 360                 /* RFC 2402 */
 361                 plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1);   /*XXX pad to 8byte?*/
 362                 ahlen = plen + sizeof(struct newah);
 363         }
 364
 365         return(ahlen);
 366 }
 367
 368 #if INET6
 369 /*
 370  * Fill in the Authentication Header and calculate checksum.
 371  */
 372 int
 373 ah6_output(m, nexthdrp, md, sav)
 374         struct mbuf *m;
 375         u_char *nexthdrp;
 376         struct mbuf *md;
 377         struct secasvar *sav;
 378 {
 379         struct mbuf *mprev;
 380         struct mbuf *mah;
 381         const struct ah_algorithm *algo;
 382         u_int32_t spi;
 383         u_char *ahsumpos = NULL;
 384         size_t plen;    /*AH payload size in bytes*/
 385         int error = 0;
 386         int ahlen;
 387         struct ip6_hdr *ip6;
 388
 389         if (m->m_len < sizeof(struct ip6_hdr)) {
 390                 ipseclog((LOG_DEBUG, "ah6_output: first mbuf too short\n"));
 391                 m_freem(m);
 392                 return EINVAL;
 393         }
 394
 395         ahlen = ah_hdrlen(sav);
 396         if (ahlen == 0)
 397                 return 0;
 398
 399         for (mprev = m; mprev && mprev->m_next != md; mprev = mprev->m_next)
 400                 ;
 401         if (!mprev || mprev->m_next != md) {
 402                 ipseclog((LOG_DEBUG, "ah6_output: md is not in chain\n"));
 403                 m_freem(m);
 404                 return EINVAL;
 405         }
 406
 407         MGET(mah, M_DONTWAIT, MT_DATA);
 408         if (!mah) {
 409                 m_freem(m);
 410                 return ENOBUFS;
 411         }
 412         if (ahlen > MLEN) {
 413                 MCLGET(mah, M_DONTWAIT);
 414                 if ((mah->m_flags & M_EXT) == 0) {
 415                         m_free(mah);
 416                         m_freem(m);
 417                         return ENOBUFS;
 418                 }
 419         }
 420         mah->m_len = ahlen;
 421         mah->m_next = md;
 422         mprev->m_next = mah;
 423         m->m_pkthdr.len += ahlen;
 424
 425         /* fix plen */
 426         if (m->m_pkthdr.len - sizeof(struct ip6_hdr) > IPV6_MAXPACKET) {
 427                 ipseclog((LOG_ERR,
 428                     "ip6_output: AH with IPv6 jumbogram is not supported\n"));
 429                 m_freem(m);
 430                 return EINVAL;
 431         }
 432         ip6 = mtod(m, struct ip6_hdr *);
 433         ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
 434
 435         if ((sav->flags & SADB_X_EXT_OLD) == 0 && !sav->replay) {
 436                 ipseclog((LOG_DEBUG, "ah6_output: internal error: "
 437                           "sav->replay is null: SPI=%u\n",
 438                           (u_int32_t)ntohl(sav->spi)));
 439                 IPSEC_STAT_INCREMENT(ipsec6stat.out_inval);
 440                 m_freem(m);
 441                 return EINVAL;
 442         }
 443
 444         algo = ah_algorithm_lookup(sav->alg_auth);
 445         if (!algo) {
 446                 ipseclog((LOG_ERR, "ah6_output: unsupported algorithm: "
 447                     "SPI=%u\n", (u_int32_t)ntohl(sav->spi)));
 448                 IPSEC_STAT_INCREMENT(ipsec6stat.out_inval);
 449                 m_freem(m);
 450                 return EINVAL;
 451         }
 452         spi = sav->spi;
 453
 454         /*
 455          * initialize AH.
 456          */
 457         if (sav->flags & SADB_X_EXT_OLD) {
 458                 struct ah *ahdr = mtod(mah, struct ah *);
 459
 460                 plen = mah->m_len - sizeof(struct ah);
 461                 ahsumpos = (u_char *)(ahdr + 1);
 462                 ahdr->ah_nxt = *nexthdrp;
 463                 *nexthdrp = IPPROTO_AH;
 464                 ahdr->ah_len = plen >> 2;
 465                 ahdr->ah_reserve = htons(0);
 466                 ahdr->ah_spi = spi;
 467                 bzero(ahdr + 1, plen);
 468         } else {
 469                 struct newah *ahdr = mtod(mah, struct newah *);
 470
 471                 plen = mah->m_len - sizeof(struct newah);
 472                 ahsumpos = (u_char *)(ahdr + 1);
 473                 ahdr->ah_nxt = *nexthdrp;
 474                 *nexthdrp = IPPROTO_AH;
 475                 ahdr->ah_len = (plen >> 2) + 1; /* plus one for seq# */
 476                 ahdr->ah_reserve = htons(0);
 477                 ahdr->ah_spi = spi;
 478                 if (sav->replay->count == ~0) {
 479                         if ((sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
 480                                 /* XXX Is it noisy ? */
 481                                 ipseclog((LOG_WARNING,
 482                                      "replay counter overflowed. %s\n",
 483                                     ipsec_logsastr(sav)));
 484                                 IPSEC_STAT_INCREMENT(ipsec6stat.out_inval);
 485                                 m_freem(m);
 486                                 return EINVAL;
 487                         }
 488                 }
 489                 lck_mtx_lock(sadb_mutex);
 490                 sav->replay->count++;
 491                 lck_mtx_unlock(sadb_mutex);
 492                 /*
 493                  * XXX sequence number must not be cycled, if the SA is
 494                  * installed by IKE daemon.
 495                  */
 496                 ahdr->ah_seq = htonl(sav->replay->count);
 497                 bzero(ahdr + 1, plen);
 498         }
 499
 500         /*
 501          * calcurate the checksum, based on security association
 502          * and the algorithm specified.
 503          */
 504         error = ah6_calccksum(m, (caddr_t)ahsumpos, plen, algo, sav);
 505         if (error) {
 506                 IPSEC_STAT_INCREMENT(ipsec6stat.out_inval);
 507                 m_freem(m);
 508         } else {
 509                 IPSEC_STAT_INCREMENT(ipsec6stat.out_success);
 510                 key_sa_recordxfer(sav, m);
 511         }
 512         IPSEC_STAT_INCREMENT(ipsec6stat.out_ahhist[sav->alg_auth]);
 513
 514         return(error);
 515 }
 516 #endif
 517
 518 #if INET
 519 /*
 520  * Find the final destination if there is loose/strict source routing option.
 521  * Returns NULL if there's no source routing options.
 522  * Returns NULL on errors too.
 523  * Note that this function will return a pointer INTO the given parameter,
 524  * struct mbuf *m.
 525  * The mbuf must be pulled up toward, at least, ip option part.
 526  */
 527 static struct in_addr *
 528 ah4_finaldst(m)
 529         struct mbuf *m;
 530 {
 531         struct ip *ip;
 532         int optlen;
 533         u_char *q;
 534         int i;
 535         int hlen;
 536
 537         if (!m)
 538                 panic("ah4_finaldst: m == NULL");
 539         ip = mtod(m, struct ip *);
 540 #ifdef _IP_VHL
 541         hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 542 #else
 543         hlen = ip->ip_hl << 2;
 544 #endif
 545
 546         if (m->m_len < hlen) {
 547                 ipseclog((LOG_DEBUG,
 548                     "ah4_finaldst: parameter mbuf wrong (not pulled up)\n"));
 549                 return NULL;
 550         }
 551
 552         if (hlen == sizeof(struct ip))
 553                 return NULL;
 554
 555         optlen = hlen - sizeof(struct ip);
 556         if (optlen < 0) {
 557                 ipseclog((LOG_DEBUG, "ah4_finaldst: wrong optlen %d\n",
 558                     optlen));
 559                 return NULL;
 560         }
 561
 562         q = (u_char *)(ip + 1);
 563         i = 0;
 564         while (i < optlen) {
 565                 if (i + IPOPT_OPTVAL >= optlen)
 566                         return NULL;
 567                 if (q[i + IPOPT_OPTVAL] == IPOPT_EOL ||
 568                     q[i + IPOPT_OPTVAL] == IPOPT_NOP ||
 569                     i + IPOPT_OLEN < optlen)
 570                         ;
 571                 else
 572                         return NULL;
 573
 574                 switch (q[i + IPOPT_OPTVAL]) {
 575                 case IPOPT_EOL:
 576                         i = optlen;     /* bye */
 577                         break;
 578                 case IPOPT_NOP:
 579                         i++;
 580                         break;
 581                 case IPOPT_LSRR:
 582                 case IPOPT_SSRR:
 583                         if (q[i + IPOPT_OLEN] < 2 + sizeof(struct in_addr) ||
 584                             optlen - i < q[i + IPOPT_OLEN]) {
 585                                 ipseclog((LOG_ERR,
 586                                     "ip_finaldst: invalid IP option "
 587                                     "(code=%02x len=%02x)\n",
 588                                     q[i + IPOPT_OPTVAL], q[i + IPOPT_OLEN]));
 589                                 return NULL;
 590                         }
 591                         i += q[i + IPOPT_OLEN] - sizeof(struct in_addr);
 592                         return (struct in_addr *)(q + i);
 593                 default:
 594                         if (q[i + IPOPT_OLEN] < 2 ||
 595                             optlen - i < q[i + IPOPT_OLEN]) {
 596                                 ipseclog((LOG_ERR,
 597                                     "ip_finaldst: invalid IP option "
 598                                     "(code=%02x len=%02x)\n",
 599                                     q[i + IPOPT_OPTVAL], q[i + IPOPT_OLEN]));
 600                                 return NULL;
 601                         }
 602                         i += q[i + IPOPT_OLEN];
 603                         break;
 604                 }
 605         }
 606         return NULL;
 607 }
 608 #endif