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
 178         /* compute original payload length */
 179         plen = 0;
 180         for (n = md; n; n = n->m_next) {
 181                 plen += n->m_len;
 182         }
 183
 184         /* if the payload is short enough, we don't need to compress */
 185         if (plen < algo->minplen) {
 186                 return 0;
 187         }
 188
 189         /*
 190          * retain the original packet for two purposes:
 191          * (1) we need to backout our changes when compression is not necessary.
 192          * (2) byte lifetime computation should use the original packet.
 193          *     see RFC2401 page 23.
 194          * compromise two m_copym().  we will be going through every byte of
 195          * the payload during compression process anyways.
 196          */
 197         mcopy = m_copym(m, 0, M_COPYALL, M_NOWAIT);
 198         if (mcopy == NULL) {
 199                 error = ENOBUFS;
 200                 return 0;
 201         }
 202         md0 = m_copym(md, 0, M_COPYALL, M_NOWAIT);
 203         if (md0 == NULL) {
 204                 m_freem(mcopy);
 205                 error = ENOBUFS;
 206                 return 0;
 207         }
 208         plen0 = plen;
 209
 210         /* make the packet over-writable */
 211         for (mprev = m; mprev && mprev->m_next != md; mprev = mprev->m_next) {
 212                 ;
 213         }
 214         if (mprev == NULL || mprev->m_next != md) {
 215                 ipseclog((LOG_DEBUG, "ipcomp%d_output: md is not in chain\n",
 216                     afnumber));
 217                 IPSEC_STAT_INCREMENT(stat->out_inval);
 218                 m_freem(m);
 219                 m_freem(md0);
 220                 m_freem(mcopy);
 221                 return EINVAL;
 222         }
 223         mprev->m_next = NULL;
 224         if ((md = ipsec_copypkt(md)) == NULL) {
 225                 m_freem(m);
 226                 m_freem(md0);
 227                 m_freem(mcopy);
 228                 error = ENOBUFS;
 229                 goto fail;
 230         }
 231         mprev->m_next = md;
 232
 233         /* compress data part */
 234         if ((*algo->compress)(m, md, &plen) || mprev->m_next == NULL) {
 235                 ipseclog((LOG_ERR, "packet compression failure\n"));
 236                 m = NULL;
 237                 m_freem(md0);
 238                 m_freem(mcopy);
 239                 IPSEC_STAT_INCREMENT(stat->out_inval);
 240                 error = EINVAL;
 241                 goto fail;
 242         }
 243         IPSEC_STAT_INCREMENT(stat->out_comphist[sav->alg_enc]);
 244         md = mprev->m_next;
 245
 246         /*
 247          * if the packet became bigger, meaningless to use IPComp.
 248          * we've only wasted our cpu time.
 249          */
 250         if (plen0 < plen) {
 251                 m_freem(md);
 252                 m_freem(mcopy);
 253                 mprev->m_next = md0;
 254                 return 0;
 255         }
 256
 257         /*
 258          * no need to backout change beyond here.
 259          */
 260         m_freem(md0);
 261         md0 = NULL;
 262
 263         m->m_pkthdr.len -= plen0;
 264         m->m_pkthdr.len += plen;
 265
 266         {
 267                 /*
 268                  * insert IPComp header.
 269                  */
 270 #if INET
 271                 struct ip *ip = NULL;
 272 #endif
 273 #if INET6
 274                 struct ip6_hdr *ip6 = NULL;
 275 #endif
 276                 size_t hlen = 0; /*ip header len*/
 277                 size_t complen = sizeof(struct ipcomp);
 278
 279                 switch (af) {
 280 #if INET
 281                 case AF_INET:
 282                         ip = mtod(m, struct ip *);
 283 #ifdef _IP_VHL
 284                         hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 285 #else
 286                         hlen = ip->ip_hl << 2;
 287 #endif
 288                         break;
 289 #endif
 290 #if INET6
 291                 case AF_INET6:
 292                         ip6 = mtod(m, struct ip6_hdr *);
 293                         hlen = sizeof(*ip6);
 294                         break;
 295 #endif
 296                 }
 297
 298                 compoff = m->m_pkthdr.len - plen;
 299
 300                 /*
 301                  * grow the mbuf to accomodate ipcomp header.
 302                  * before: IP ... payload
 303                  * after:  IP ... ipcomp payload
 304                  */
 305                 if (M_LEADINGSPACE(md) < complen) {
 306                         MGET(n, M_DONTWAIT, MT_DATA);
 307                         if (!n) {
 308                                 m_freem(m);
 309                                 error = ENOBUFS;
 310                                 goto fail;
 311                         }
 312                         n->m_len = complen;
 313                         mprev->m_next = n;
 314                         n->m_next = md;
 315                         m->m_pkthdr.len += complen;
 316                         ipcomp = mtod(n, struct ipcomp *);
 317                 } else {
 318                         md->m_len += complen;
 319                         md->m_data -= complen;
 320                         m->m_pkthdr.len += complen;
 321                         ipcomp = mtod(md, struct ipcomp *);
 322                 }
 323
 324                 bzero(ipcomp, sizeof(*ipcomp));
 325                 ipcomp->comp_nxt = *nexthdrp;
 326                 *nexthdrp = IPPROTO_IPCOMP;
 327                 ipcomp->comp_cpi = htons(cpi);
 328                 switch (af) {
 329 #if INET
 330                 case AF_INET:
 331                         if (compoff + complen + plen < IP_MAXPACKET) {
 332                                 ip->ip_len = htons(compoff + complen + plen);
 333                         } else {
 334                                 ipseclog((LOG_ERR,
 335                                     "IPv4 ESP output: size exceeds limit\n"));
 336                                 IPSEC_STAT_INCREMENT(ipsecstat.out_inval);
 337                                 m_freem(m);
 338                                 error = EMSGSIZE;
 339                                 goto fail;
 340                         }
 341                         break;
 342 #endif
 343 #if INET6
 344                 case AF_INET6:
 345                         /* total packet length will be computed in ip6_output() */
 346                         break;
 347 #endif
 348                 }
 349         }
 350
 351         if (!m) {
 352                 ipseclog((LOG_DEBUG,
 353                     "NULL mbuf after compression in ipcomp%d_output",
 354                     afnumber));
 355                 IPSEC_STAT_INCREMENT(stat->out_inval);
 356         }
 357         IPSEC_STAT_INCREMENT(stat->out_success);
 358
 359         /* compute byte lifetime against original packet */
 360         key_sa_recordxfer(sav, mcopy);
 361         m_freem(mcopy);
 362
 363         return 0;
 364
 365 fail:
 366 #if 1
 367         return error;
 368 #else
 369         panic("something bad in ipcomp_output");
 370 #endif
 371 }
 372
 373 #if INET
 374 int
 375 ipcomp4_output(struct mbuf *m, struct secasvar *sav)
 376 {
 377         struct ip *ip;
 378         if (m->m_len < sizeof(struct ip)) {
 379                 ipseclog((LOG_DEBUG, "ipcomp4_output: first mbuf too short\n"));
 380                 IPSEC_STAT_INCREMENT(ipsecstat.out_inval);
 381                 m_freem(m);
 382                 return 0;
 383         }
 384         ip = mtod(m, struct ip *);
 385         /* XXX assumes that m->m_next points to payload */
 386         return ipcomp_output(m, &ip->ip_p, m->m_next, AF_INET, sav);
 387 }
 388 #endif /*INET*/
 389
 390 #if INET6
 391 int
 392 ipcomp6_output(
 393         struct mbuf *m,
 394         u_char *nexthdrp,
 395         struct mbuf *md,
 396         struct secasvar *sav)
 397 {
 398         if (m->m_len < sizeof(struct ip6_hdr)) {
 399                 ipseclog((LOG_DEBUG, "ipcomp6_output: first mbuf too short\n"));
 400                 IPSEC_STAT_INCREMENT(ipsec6stat.out_inval);
 401                 m_freem(m);
 402                 return 0;
 403         }
 404         return ipcomp_output(m, nexthdrp, md, AF_INET6, sav);
 405 }
 406 #endif /*INET6*/