bsd/netinet6/ipcomp_output.c

   1 /*
   2  * Copyright (c) 2016 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29 /*      $FreeBSD: src/sys/netinet6/ipcomp_output.c,v 1.1.2.2 2001/07/03 11:01:54 ume Exp $      */
  30 /*      $KAME: ipcomp_output.c,v 1.23 2001/01/23 08:59:37 itojun Exp $  */
  31
  32 /*
  33  * Copyright (C) 1999 WIDE Project.
  34  * All rights reserved.
  35  *
  36  * Redistribution and use in source and binary forms, with or without
  37  * modification, are permitted provided that the following conditions
  38  * are met:
  39  * 1. Redistributions of source code must retain the above copyright
  40  *    notice, this list of conditions and the following disclaimer.
  41  * 2. Redistributions in binary form must reproduce the above copyright
  42  *    notice, this list of conditions and the following disclaimer in the
  43  *    documentation and/or other materials provided with the distribution.
  44  * 3. Neither the name of the project nor the names of its contributors
  45  *    may be used to endorse or promote products derived from this software
  46  *    without specific prior written permission.
  47  *
  48  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  49  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  50  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  51  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  52  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  53  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  54  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  55  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  56  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  57  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  58  * SUCH DAMAGE.
  59  */
  60
  61 /*
  62  * RFC2393 IP payload compression protocol (IPComp).
  63  */
  64
  65
  66 #include <sys/param.h>
  67 #include <sys/systm.h>
  68 #include <sys/malloc.h>
  69 #include <sys/mbuf.h>
  70 #include <sys/domain.h>
  71 #include <sys/protosw.h>
  72 #include <sys/socket.h>
  73 #include <sys/errno.h>
  74 #include <sys/time.h>
  75 #include <sys/kernel.h>
  76 #include <sys/syslog.h>
  77
  78 #include <net/if.h>
  79 #include <net/route.h>
  80 #include <libkern/zlib.h>
  81 #include <kern/cpu_number.h>
  82 #include <kern/locks.h>
  83
  84 #include <netinet/in.h>
  85 #include <netinet/in_systm.h>
  86 #include <netinet/in_var.h>
  87 #include <netinet/ip.h>
  88 #include <netinet/ip_var.h>
  89 #include <netinet/ip_ecn.h>
  90
  91 #if INET6
  92 #include <netinet/ip6.h>
  93 #include <netinet6/ip6_var.h>
  94 #endif
  95 #include <netinet6/ipcomp.h>
  96 #if INET6
  97 #include <netinet6/ipcomp6.h>
  98 #endif
  99
 100 #include <netinet6/ipsec.h>
 101 #if INET6
 102 #include <netinet6/ipsec6.h>
 103 #endif
 104 #include <netkey/key.h>
 105 #include <netkey/keydb.h>
 106
 107 #include <net/net_osdep.h>
 108
 109
 110 static int ipcomp_output(struct mbuf *, u_char *, struct mbuf *,
 111         int, struct secasvar *sav);
 112
 113 /*
 114  * Modify the packet so that the payload is compressed.
 115  * The mbuf (m) must start with IPv4 or IPv6 header.
 116  * On failure, free the given mbuf and return non-zero.
 117  *
 118  * on invocation:
 119  *      m   nexthdrp md
 120  *      v   v        v
 121  *      IP ......... payload
 122  * during the encryption:
 123  *      m   nexthdrp mprev md
 124  *      v   v        v     v
 125  *      IP ............... ipcomp payload
 126  *                         <-----><----->
 127  *                         complen  plen
 128  *      <-> hlen
 129  *      <-----------------> compoff
 130  */
 131 static int
 132 ipcomp_output(struct mbuf *m, u_char *nexthdrp, struct mbuf *md, int af, struct secasvar *sav)
 133 {
 134         struct mbuf *n;
 135         struct mbuf *md0;
 136         struct mbuf *mcopy;
 137         struct mbuf *mprev;
 138         struct ipcomp *ipcomp;
 139         const struct ipcomp_algorithm *algo;
 140         u_int16_t cpi;          /* host order */
 141         size_t plen0, plen;     /*payload length to be compressed*/
 142         size_t compoff;
 143         int afnumber;
 144         int error = 0;
 145         struct ipsecstat *stat;
 146
 147         switch (af) {
 148 #if INET
 149         case AF_INET:
 150                 afnumber = 4;
 151                 stat = &ipsecstat;
 152                 break;
 153 #endif
 154 #if INET6
 155         case AF_INET6:
 156                 afnumber = 6;
 157                 stat = &ipsec6stat;
 158                 break;
 159 #endif
 160         default:
 161                 ipseclog((LOG_ERR, "ipcomp_output: unsupported af %d\n", af));
 162                 return 0;       /* no change at all */
 163         }
 164
 165         /* grab parameters */
 166         algo = ipcomp_algorithm_lookup(sav->alg_enc);
 167         if ((ntohl(sav->spi) & ~0xffff) != 0 || !algo) {
 168                 IPSEC_STAT_INCREMENT(stat->out_inval);
 169                 m_freem(m);
 170                 return EINVAL;
 171         }
 172         if ((sav->flags & SADB_X_EXT_RAWCPI) == 0)
 173                 cpi = sav->alg_enc;
 174         else
 175                 cpi = ntohl(sav->spi) & 0xffff;
 176
 177         /* compute original payload length */
 178         plen = 0;
 179         for (n = md; n; n = n->m_next)
 180                 plen += n->m_len;
 181
 182         /* if the payload is short enough, we don't need to compress */
 183         if (plen < algo->minplen)
 184                 return 0;
 185
 186         /*
 187          * retain the original packet for two purposes:
 188          * (1) we need to backout our changes when compression is not necessary.
 189          * (2) byte lifetime computation should use the original packet.
 190          *     see RFC2401 page 23.
 191          * compromise two m_copym().  we will be going through every byte of
 192          * the payload during compression process anyways.
 193          */
 194         mcopy = m_copym(m, 0, M_COPYALL, M_NOWAIT);
 195         if (mcopy == NULL) {
 196                 error = ENOBUFS;
 197                 return 0;
 198         }
 199         md0 = m_copym(md, 0, M_COPYALL, M_NOWAIT);
 200         if (md0 == NULL) {
 201                 m_freem(mcopy);
 202                 error = ENOBUFS;
 203                 return 0;
 204         }
 205         plen0 = plen;
 206
 207         /* make the packet over-writable */
 208         for (mprev = m; mprev && mprev->m_next != md; mprev = mprev->m_next)
 209                 ;
 210         if (mprev == NULL || mprev->m_next != md) {
 211                 ipseclog((LOG_DEBUG, "ipcomp%d_output: md is not in chain\n",
 212                     afnumber));
 213                 IPSEC_STAT_INCREMENT(stat->out_inval);
 214                 m_freem(m);
 215                 m_freem(md0);
 216                 m_freem(mcopy);
 217                 return EINVAL;
 218         }
 219         mprev->m_next = NULL;
 220         if ((md = ipsec_copypkt(md)) == NULL) {
 221                 m_freem(m);
 222                 m_freem(md0);
 223                 m_freem(mcopy);
 224                 error = ENOBUFS;
 225                 goto fail;
 226         }
 227         mprev->m_next = md;
 228
 229         /* compress data part */
 230         if ((*algo->compress)(m, md, &plen) || mprev->m_next == NULL) {
 231                 ipseclog((LOG_ERR, "packet compression failure\n"));
 232                 m = NULL;
 233                 m_freem(md0);
 234                 m_freem(mcopy);
 235                 IPSEC_STAT_INCREMENT(stat->out_inval);
 236                 error = EINVAL;
 237                 goto fail;
 238         }
 239         IPSEC_STAT_INCREMENT(stat->out_comphist[sav->alg_enc]);
 240         md = mprev->m_next;
 241
 242         /*
 243          * if the packet became bigger, meaningless to use IPComp.
 244          * we've only wasted our cpu time.
 245          */
 246         if (plen0 < plen) {
 247                 m_freem(md);
 248                 m_freem(mcopy);
 249                 mprev->m_next = md0;
 250                 return 0;
 251         }
 252
 253         /*
 254          * no need to backout change beyond here.
 255          */
 256         m_freem(md0);
 257         md0 = NULL;
 258
 259         m->m_pkthdr.len -= plen0;
 260         m->m_pkthdr.len += plen;
 261
 262     {
 263         /*
 264          * insert IPComp header.
 265          */
 266 #if INET
 267         struct ip *ip = NULL;
 268 #endif
 269 #if INET6
 270         struct ip6_hdr *ip6 = NULL;
 271 #endif
 272         size_t hlen = 0;        /*ip header len*/
 273         size_t complen = sizeof(struct ipcomp);
 274
 275         switch (af) {
 276 #if INET
 277         case AF_INET:
 278                 ip = mtod(m, struct ip *);
 279 #ifdef _IP_VHL
 280                 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 281 #else
 282                 hlen = ip->ip_hl << 2;
 283 #endif
 284                 break;
 285 #endif
 286 #if INET6
 287         case AF_INET6:
 288                 ip6 = mtod(m, struct ip6_hdr *);
 289                 hlen = sizeof(*ip6);
 290                 break;
 291 #endif
 292         }
 293
 294         compoff = m->m_pkthdr.len - plen;
 295
 296         /*
 297          * grow the mbuf to accomodate ipcomp header.
 298          * before: IP ... payload
 299          * after:  IP ... ipcomp payload
 300          */
 301         if (M_LEADINGSPACE(md) < complen) {
 302                 MGET(n, M_DONTWAIT, MT_DATA);
 303                 if (!n) {
 304                         m_freem(m);
 305                         error = ENOBUFS;
 306                         goto fail;
 307                 }
 308                 n->m_len = complen;
 309                 mprev->m_next = n;
 310                 n->m_next = md;
 311                 m->m_pkthdr.len += complen;
 312                 ipcomp = mtod(n, struct ipcomp *);
 313         } else {
 314                 md->m_len += complen;
 315                 md->m_data -= complen;
 316                 m->m_pkthdr.len += complen;
 317                 ipcomp = mtod(md, struct ipcomp *);
 318         }
 319
 320         bzero(ipcomp, sizeof(*ipcomp));
 321         ipcomp->comp_nxt = *nexthdrp;
 322         *nexthdrp = IPPROTO_IPCOMP;
 323         ipcomp->comp_cpi = htons(cpi);
 324         switch (af) {
 325 #if INET
 326         case AF_INET:
 327                 if (compoff + complen + plen < IP_MAXPACKET)
 328                         ip->ip_len = htons(compoff + complen + plen);
 329                 else {
 330                         ipseclog((LOG_ERR,
 331                             "IPv4 ESP output: size exceeds limit\n"));
 332                         IPSEC_STAT_INCREMENT(ipsecstat.out_inval);
 333                         m_freem(m);
 334                         error = EMSGSIZE;
 335                         goto fail;
 336                 }
 337                 break;
 338 #endif
 339 #if INET6
 340         case AF_INET6:
 341                 /* total packet length will be computed in ip6_output() */
 342                 break;
 343 #endif
 344         }
 345     }
 346
 347         if (!m) {
 348                 ipseclog((LOG_DEBUG,
 349                     "NULL mbuf after compression in ipcomp%d_output",
 350                     afnumber));
 351                 IPSEC_STAT_INCREMENT(stat->out_inval);
 352         }
 353                 IPSEC_STAT_INCREMENT(stat->out_success);
 354
 355         /* compute byte lifetime against original packet */
 356         key_sa_recordxfer(sav, mcopy);
 357         m_freem(mcopy);
 358
 359         return 0;
 360
 361 fail:
 362 #if 1
 363         return error;
 364 #else
 365         panic("something bad in ipcomp_output");
 366 #endif
 367 }
 368
 369 #if INET
 370 int
 371 ipcomp4_output(struct mbuf *m, struct secasvar *sav)
 372 {
 373         struct ip *ip;
 374         if (m->m_len < sizeof(struct ip)) {
 375                 ipseclog((LOG_DEBUG, "ipcomp4_output: first mbuf too short\n"));
 376                 IPSEC_STAT_INCREMENT(ipsecstat.out_inval);
 377                 m_freem(m);
 378                 return 0;
 379         }
 380         ip = mtod(m, struct ip *);
 381         /* XXX assumes that m->m_next points to payload */
 382         return ipcomp_output(m, &ip->ip_p, m->m_next, AF_INET, sav);
 383 }
 384 #endif /*INET*/
 385
 386 #if INET6
 387 int
 388 ipcomp6_output(
 389         struct mbuf *m,
 390         u_char *nexthdrp,
 391         struct mbuf *md,
 392         struct secasvar *sav)
 393 {
 394         if (m->m_len < sizeof(struct ip6_hdr)) {
 395                 ipseclog((LOG_DEBUG, "ipcomp6_output: first mbuf too short\n"));
 396                 IPSEC_STAT_INCREMENT(ipsec6stat.out_inval);
 397                 m_freem(m);
 398                 return 0;
 399         }
 400         return ipcomp_output(m, nexthdrp, md, AF_INET6, sav);
 401 }
 402 #endif /*INET6*/