bsd/netinet6/esp_output.c

   1 /*
   2  * Copyright (c) 2008-2016 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/esp_output.c,v 1.1.2.3 2002/04/28 05:40:26 suz Exp $ */
  30 /*      $KAME: esp_output.c,v 1.44 2001/07/26 06:53:15 jinmei Exp $     */
  31
  32 /*
  33  * Copyright (C) 1995, 1996, 1997, and 1998 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 #define _IP_VHL
  62
  63 /*
  64  * RFC1827/2406 Encapsulated Security Payload.
  65  */
  66
  67 #include <sys/param.h>
  68 #include <sys/systm.h>
  69 #include <sys/malloc.h>
  70 #include <sys/mbuf.h>
  71 #include <sys/domain.h>
  72 #include <sys/protosw.h>
  73 #include <sys/socket.h>
  74 #include <sys/socketvar.h>
  75 #include <sys/errno.h>
  76 #include <sys/time.h>
  77 #include <sys/kernel.h>
  78 #include <sys/syslog.h>
  79
  80 #include <net/if.h>
  81 #include <net/route.h>
  82
  83 #include <netinet/in.h>
  84 #include <netinet/in_systm.h>
  85 #include <netinet/ip.h>
  86 #include <netinet/in_var.h>
  87 #include <netinet/udp.h> /* for nat traversal */
  88
  89 #if INET6
  90 #include <netinet/ip6.h>
  91 #include <netinet6/ip6_var.h>
  92 #include <netinet/icmp6.h>
  93 #endif
  94
  95 #include <netinet6/ipsec.h>
  96 #if INET6
  97 #include <netinet6/ipsec6.h>
  98 #endif
  99 #include <netinet6/ah.h>
 100 #if INET6
 101 #include <netinet6/ah6.h>
 102 #endif
 103 #include <netinet6/esp.h>
 104 #if INET6
 105 #include <netinet6/esp6.h>
 106 #endif
 107 #include <netkey/key.h>
 108 #include <netkey/keydb.h>
 109
 110 #include <net/net_osdep.h>
 111
 112 #include <sys/kdebug.h>
 113 #define DBG_LAYER_BEG           NETDBG_CODE(DBG_NETIPSEC, 1)
 114 #define DBG_LAYER_END           NETDBG_CODE(DBG_NETIPSEC, 3)
 115 #define DBG_FNC_ESPOUT          NETDBG_CODE(DBG_NETIPSEC, (4 << 8))
 116 #define DBG_FNC_ENCRYPT         NETDBG_CODE(DBG_NETIPSEC, (5 << 8))
 117
 118 static int esp_output(struct mbuf *, u_char *, struct mbuf *,
 119         int, struct secasvar *sav);
 120
 121 extern int      esp_udp_encap_port;
 122 extern u_int64_t natt_now;
 123
 124 extern lck_mtx_t *sadb_mutex;
 125
 126 /*
 127  * compute ESP header size.
 128  */
 129 size_t
 130 esp_hdrsiz(__unused struct ipsecrequest *isr)
 131 {
 132
 133 #if 0
 134         /* sanity check */
 135         if (isr == NULL)
 136                 panic("esp_hdrsiz: NULL was passed.\n");
 137
 138
 139         lck_mtx_lock(sadb_mutex);
 140         {
 141                 struct secasvar *sav;
 142                 const struct esp_algorithm *algo;
 143                 const struct ah_algorithm *aalgo;
 144                 size_t ivlen;
 145                 size_t authlen;
 146                 size_t hdrsiz;
 147                 size_t maxpad;
 148
 149                 /*%%%% this needs to change - no sav in ipsecrequest any more */
 150                 sav = isr->sav;
 151
 152                 if (isr->saidx.proto != IPPROTO_ESP)
 153                         panic("unsupported mode passed to esp_hdrsiz");
 154
 155                 if (sav == NULL)
 156                         goto estimate;
 157                 if (sav->state != SADB_SASTATE_MATURE
 158                  && sav->state != SADB_SASTATE_DYING)
 159                         goto estimate;
 160
 161                 /* we need transport mode ESP. */
 162                 algo = esp_algorithm_lookup(sav->alg_enc);
 163                 if (!algo)
 164                         goto estimate;
 165                 ivlen = sav->ivlen;
 166                 if (ivlen < 0)
 167                         goto estimate;
 168
 169                 if (algo->padbound)
 170                         maxpad = algo->padbound;
 171                 else
 172                         maxpad = 4;
 173                 maxpad += 1; /* maximum 'extendsiz' is padbound + 1, see esp_output */
 174
 175                 if (sav->flags & SADB_X_EXT_OLD) {
 176                         /* RFC 1827 */
 177                         hdrsiz = sizeof(struct esp) + ivlen + maxpad;
 178                 } else {
 179                         /* RFC 2406 */
 180                         aalgo = ah_algorithm_lookup(sav->alg_auth);
 181                         if (aalgo && sav->replay && sav->key_auth)
 182                                 authlen = (aalgo->sumsiz)(sav);
 183                         else
 184                                 authlen = 0;
 185                         hdrsiz = sizeof(struct newesp) + ivlen + maxpad + authlen;
 186                 }
 187
 188                 /*
 189                  * If the security association indicates that NATT is required,
 190                  * add the size of the NATT encapsulation header:
 191                  */
 192                 if ((sav->flags & SADB_X_EXT_NATT) != 0) hdrsiz += sizeof(struct udphdr) + 4;
 193
 194                 lck_mtx_unlock(sadb_mutex);
 195                 return hdrsiz;
 196         }
 197 estimate:
 198    lck_mtx_unlock(sadb_mutex);
 199 #endif
 200         /*
 201          * ASSUMING:
 202          *      sizeof(struct newesp) > sizeof(struct esp). (8)
 203          *      esp_max_ivlen() = max ivlen for CBC mode
 204          *      17 = (maximum padding length without random padding length)
 205          *         + (Pad Length field) + (Next Header field).
 206          *      64 = maximum ICV we support.
 207          *  sizeof(struct udphdr) in case NAT traversal is used
 208          */
 209         return sizeof(struct newesp) + esp_max_ivlen() + 17 + AH_MAXSUMSIZE + sizeof(struct udphdr);
 210 }
 211
 212 /*
 213  * Modify the packet so that the payload is encrypted.
 214  * The mbuf (m) must start with IPv4 or IPv6 header.
 215  * On failure, free the given mbuf and return NULL.
 216  *
 217  * on invocation:
 218  *      m   nexthdrp md
 219  *      v   v        v
 220  *      IP ......... payload
 221  * during the encryption:
 222  *      m   nexthdrp mprev md
 223  *      v   v        v     v
 224  *      IP ............... esp iv payload pad padlen nxthdr
 225  *                         <--><-><------><--------------->
 226  *                         esplen plen    extendsiz
 227  *                             ivlen
 228  *                         <-----> esphlen
 229  *      <-> hlen
 230  *      <-----------------> espoff
 231  */
 232 static int
 233 esp_output(
 234         struct mbuf *m,
 235         u_char *nexthdrp,
 236         struct mbuf *md,
 237         int af,
 238         struct secasvar *sav)
 239 {
 240         struct mbuf *n;
 241         struct mbuf *mprev;
 242         struct esp *esp;
 243         struct esptail *esptail;
 244         const struct esp_algorithm *algo;
 245         u_int32_t spi;
 246         u_int8_t nxt = 0;
 247         size_t plen;    /*payload length to be encrypted*/
 248         size_t espoff;
 249         size_t esphlen; /* sizeof(struct esp/newesp) + ivlen */
 250         int ivlen;
 251         int afnumber;
 252         size_t extendsiz;
 253         int error = 0;
 254         struct ipsecstat *stat;
 255         struct udphdr *udp = NULL;
 256         int     udp_encapsulate = (sav->flags & SADB_X_EXT_NATT && (af == AF_INET || af == AF_INET6) &&
 257                         (esp_udp_encap_port & 0xFFFF) != 0);
 258
 259         KERNEL_DEBUG(DBG_FNC_ESPOUT | DBG_FUNC_START, sav->ivlen,0,0,0,0);
 260         switch (af) {
 261 #if INET
 262         case AF_INET:
 263                 afnumber = 4;
 264                 stat = &ipsecstat;
 265                 break;
 266 #endif
 267 #if INET6
 268         case AF_INET6:
 269                 afnumber = 6;
 270                 stat = &ipsec6stat;
 271                 break;
 272 #endif
 273         default:
 274                 ipseclog((LOG_ERR, "esp_output: unsupported af %d\n", af));
 275                 KERNEL_DEBUG(DBG_FNC_ESPOUT | DBG_FUNC_END, 1,0,0,0,0);
 276                 return 0;       /* no change at all */
 277         }
 278
 279         /* some sanity check */
 280         if ((sav->flags & SADB_X_EXT_OLD) == 0 && !sav->replay) {
 281                 switch (af) {
 282 #if INET
 283                 case AF_INET:
 284                     {
 285                         struct ip *ip;
 286
 287                         ip = mtod(m, struct ip *);
 288                         ipseclog((LOG_DEBUG, "esp4_output: internal error: "
 289                                 "sav->replay is null: %x->%x, SPI=%u\n",
 290                                 (u_int32_t)ntohl(ip->ip_src.s_addr),
 291                                 (u_int32_t)ntohl(ip->ip_dst.s_addr),
 292                                 (u_int32_t)ntohl(sav->spi)));
 293                         IPSEC_STAT_INCREMENT(ipsecstat.out_inval);
 294                         break;
 295                     }
 296 #endif /*INET*/
 297 #if INET6
 298                 case AF_INET6:
 299                         ipseclog((LOG_DEBUG, "esp6_output: internal error: "
 300                                 "sav->replay is null: SPI=%u\n",
 301                                 (u_int32_t)ntohl(sav->spi)));
 302                         IPSEC_STAT_INCREMENT(ipsec6stat.out_inval);
 303                         break;
 304 #endif /*INET6*/
 305                 default:
 306                         panic("esp_output: should not reach here");
 307                 }
 308                 m_freem(m);
 309                 KERNEL_DEBUG(DBG_FNC_ESPOUT | DBG_FUNC_END, 2,0,0,0,0);
 310                 return EINVAL;
 311         }
 312
 313         algo = esp_algorithm_lookup(sav->alg_enc);
 314         if (!algo) {
 315                 ipseclog((LOG_ERR, "esp_output: unsupported algorithm: "
 316                     "SPI=%u\n", (u_int32_t)ntohl(sav->spi)));
 317                 m_freem(m);
 318                 KERNEL_DEBUG(DBG_FNC_ESPOUT | DBG_FUNC_END, 3,0,0,0,0);
 319                 return EINVAL;
 320         }
 321         spi = sav->spi;
 322         ivlen = sav->ivlen;
 323         /* should be okey */
 324         if (ivlen < 0) {
 325                 panic("invalid ivlen");
 326         }
 327
 328     {
 329         /*
 330          * insert ESP header.
 331          * XXX inserts ESP header right after IPv4 header.  should
 332          * chase the header chain.
 333          * XXX sequential number
 334          */
 335 #if INET
 336         struct ip *ip = NULL;
 337 #endif
 338 #if INET6
 339         struct ip6_hdr *ip6 = NULL;
 340 #endif
 341         size_t esplen;  /* sizeof(struct esp/newesp) */
 342         size_t hlen = 0;        /* ip header len */
 343
 344         if (sav->flags & SADB_X_EXT_OLD) {
 345                 /* RFC 1827 */
 346                 esplen = sizeof(struct esp);
 347         } else {
 348                 /* RFC 2406 */
 349                 if (sav->flags & SADB_X_EXT_DERIV)
 350                         esplen = sizeof(struct esp);
 351                 else
 352                         esplen = sizeof(struct newesp);
 353         }
 354         esphlen = esplen + ivlen;
 355
 356         for (mprev = m; mprev && mprev->m_next != md; mprev = mprev->m_next)
 357                 ;
 358         if (mprev == NULL || mprev->m_next != md) {
 359                 ipseclog((LOG_DEBUG, "esp%d_output: md is not in chain\n",
 360                     afnumber));
 361                 m_freem(m);
 362                 KERNEL_DEBUG(DBG_FNC_ESPOUT | DBG_FUNC_END, 4,0,0,0,0);
 363                 return EINVAL;
 364         }
 365
 366         plen = 0;
 367         for (n = md; n; n = n->m_next)
 368                 plen += n->m_len;
 369
 370         switch (af) {
 371 #if INET
 372         case AF_INET:
 373                 ip = mtod(m, struct ip *);
 374 #ifdef _IP_VHL
 375                 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 376 #else
 377                 hlen = ip->ip_hl << 2;
 378 #endif
 379                 break;
 380 #endif
 381 #if INET6
 382         case AF_INET6:
 383                 ip6 = mtod(m, struct ip6_hdr *);
 384                 hlen = sizeof(*ip6);
 385                 break;
 386 #endif
 387         }
 388
 389         /* make the packet over-writable */
 390         mprev->m_next = NULL;
 391         if ((md = ipsec_copypkt(md)) == NULL) {
 392                 m_freem(m);
 393                 error = ENOBUFS;
 394                 goto fail;
 395         }
 396         mprev->m_next = md;
 397
 398         /*
 399          * Translate UDP source port back to its original value.
 400          * SADB_X_EXT_NATT_MULTIPLEUSERS is only set for transort mode.
 401          */
 402         if ((sav->flags & SADB_X_EXT_NATT_MULTIPLEUSERS) != 0) {
 403                 /* if not UDP - drop it */
 404                 if (ip->ip_p != IPPROTO_UDP)    {
 405                         IPSEC_STAT_INCREMENT(ipsecstat.out_inval);
 406                         m_freem(m);
 407                         error = EINVAL;
 408                         goto fail;
 409                 }
 410
 411                 udp = mtod(md, struct udphdr *);
 412
 413                 /* if src port not set in sav - find it */
 414                 if (sav->natt_encapsulated_src_port == 0)
 415                         if (key_natt_get_translated_port(sav) == 0) {
 416                                 m_freem(m);
 417                                 error = EINVAL;
 418                                 goto fail;
 419                         }
 420                 if (sav->remote_ike_port == htons(udp->uh_dport)) {
 421                         /* translate UDP port */
 422                         udp->uh_dport = sav->natt_encapsulated_src_port;
 423                         udp->uh_sum = 0;        /* don't need checksum with ESP auth */
 424                 } else {
 425                         /* drop the packet - can't translate the port */
 426                         IPSEC_STAT_INCREMENT(ipsecstat.out_inval);
 427                         m_freem(m);
 428                         error = EINVAL;
 429                         goto fail;
 430                 }
 431         }
 432
 433
 434         espoff = m->m_pkthdr.len - plen;
 435
 436         if (udp_encapsulate) {
 437                 esphlen += sizeof(struct udphdr);
 438                 espoff += sizeof(struct udphdr);
 439         }
 440
 441         /*
 442          * grow the mbuf to accomodate ESP header.
 443          * before: IP ... payload
 444          * after:  IP ... [UDP] ESP IV payload
 445          */
 446         if (M_LEADINGSPACE(md) < esphlen || (md->m_flags & M_EXT) != 0) {
 447                 MGET(n, M_DONTWAIT, MT_DATA);
 448                 if (!n) {
 449                         m_freem(m);
 450                         error = ENOBUFS;
 451                         goto fail;
 452                 }
 453                 n->m_len = esphlen;
 454                 mprev->m_next = n;
 455                 n->m_next = md;
 456                 m->m_pkthdr.len += esphlen;
 457                 if (udp_encapsulate) {
 458                         udp = mtod(n, struct udphdr *);
 459                         esp = (struct esp *)(void *)((caddr_t)udp + sizeof(struct udphdr));
 460                 } else {
 461                         esp = mtod(n, struct esp *);
 462                 }
 463         } else {
 464                 md->m_len += esphlen;
 465                 md->m_data -= esphlen;
 466                 m->m_pkthdr.len += esphlen;
 467                 esp = mtod(md, struct esp *);
 468                 if (udp_encapsulate) {
 469                         udp = mtod(md, struct udphdr *);
 470                         esp = (struct esp *)(void *)((caddr_t)udp + sizeof(struct udphdr));
 471                 } else {
 472                         esp = mtod(md, struct esp *);
 473                 }
 474         }
 475
 476         switch (af) {
 477 #if INET
 478         case AF_INET:
 479                 if (esphlen < (IP_MAXPACKET - ntohs(ip->ip_len)))
 480                         ip->ip_len = htons(ntohs(ip->ip_len) + esphlen);
 481                 else {
 482                         ipseclog((LOG_ERR,
 483                             "IPv4 ESP output: size exceeds limit\n"));
 484                         IPSEC_STAT_INCREMENT(ipsecstat.out_inval);
 485                         m_freem(m);
 486                         error = EMSGSIZE;
 487                         goto fail;
 488                 }
 489                 break;
 490 #endif
 491 #if INET6
 492         case AF_INET6:
 493                 /* total packet length will be computed in ip6_output() */
 494                 break;
 495 #endif
 496         }
 497     }
 498
 499         /* initialize esp header. */
 500         esp->esp_spi = spi;
 501         if ((sav->flags & SADB_X_EXT_OLD) == 0) {
 502                 struct newesp *nesp;
 503                 nesp = (struct newesp *)esp;
 504                 if (sav->replay->count == ~0) {
 505                         if ((sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
 506                                 /* XXX Is it noisy ? */
 507                                 ipseclog((LOG_WARNING,
 508                                     "replay counter overflowed. %s\n",
 509                                     ipsec_logsastr(sav)));
 510                                 IPSEC_STAT_INCREMENT(stat->out_inval);
 511                                 m_freem(m);
 512                                 KERNEL_DEBUG(DBG_FNC_ESPOUT | DBG_FUNC_END, 5,0,0,0,0);
 513                                 return EINVAL;
 514                         }
 515                 }
 516                 lck_mtx_lock(sadb_mutex);
 517                 sav->replay->count++;
 518                 lck_mtx_unlock(sadb_mutex);
 519                 /*
 520                  * XXX sequence number must not be cycled, if the SA is
 521                  * installed by IKE daemon.
 522                  */
 523                 nesp->esp_seq = htonl(sav->replay->count);
 524         }
 525
 526     {
 527         /*
 528          * find the last mbuf. make some room for ESP trailer.
 529          */
 530 #if INET
 531         struct ip *ip = NULL;
 532 #endif
 533         size_t padbound;
 534         u_char *extend;
 535         int i;
 536         int randpadmax;
 537
 538         if (algo->padbound)
 539                 padbound = algo->padbound;
 540         else
 541                 padbound = 4;
 542         /* ESP packet, including nxthdr field, must be length of 4n */
 543         if (padbound < 4)
 544                 padbound = 4;
 545
 546         extendsiz = padbound - (plen % padbound);
 547         if (extendsiz == 1)
 548                 extendsiz = padbound + 1;
 549
 550         /* random padding */
 551         switch (af) {
 552 #if INET
 553         case AF_INET:
 554                 randpadmax = ip4_esp_randpad;
 555                 break;
 556 #endif
 557 #if INET6
 558         case AF_INET6:
 559                 randpadmax = ip6_esp_randpad;
 560                 break;
 561 #endif
 562         default:
 563                 randpadmax = -1;
 564                 break;
 565         }
 566         if (randpadmax < 0 || plen + extendsiz >= randpadmax)
 567                 ;
 568         else {
 569                 int pad;
 570
 571                 /* round */
 572                 randpadmax = (randpadmax / padbound) * padbound;
 573                 pad = (randpadmax - plen + extendsiz) / padbound;
 574
 575                 if (pad > 0)
 576                         pad = (random() % pad) * padbound;
 577                 else
 578                         pad = 0;
 579
 580                 /*
 581                  * make sure we do not pad too much.
 582                  * MLEN limitation comes from the trailer attachment
 583                  * code below.
 584                  * 256 limitation comes from sequential padding.
 585                  * also, the 1-octet length field in ESP trailer imposes
 586                  * limitation (but is less strict than sequential padding
 587                  * as length field do not count the last 2 octets).
 588                  */
 589                 if (extendsiz + pad <= MLEN && extendsiz + pad < 256)
 590                         extendsiz += pad;
 591         }
 592
 593 #if DIAGNOSTIC
 594         if (extendsiz > MLEN || extendsiz >= 256)
 595                 panic("extendsiz too big in esp_output");
 596 #endif
 597
 598         n = m;
 599         while (n->m_next)
 600                 n = n->m_next;
 601
 602         /*
 603          * if M_EXT, the external mbuf data may be shared among
 604          * two consequtive TCP packets, and it may be unsafe to use the
 605          * trailing space.
 606          */
 607         if (!(n->m_flags & M_EXT) && extendsiz < M_TRAILINGSPACE(n)) {
 608                 extend = mtod(n, u_char *) + n->m_len;
 609                 n->m_len += extendsiz;
 610                 m->m_pkthdr.len += extendsiz;
 611         } else {
 612                 struct mbuf *nn;
 613
 614                 MGET(nn, M_DONTWAIT, MT_DATA);
 615                 if (!nn) {
 616                         ipseclog((LOG_DEBUG, "esp%d_output: can't alloc mbuf",
 617                             afnumber));
 618                         m_freem(m);
 619                         error = ENOBUFS;
 620                         goto fail;
 621                 }
 622                 extend = mtod(nn, u_char *);
 623                 nn->m_len = extendsiz;
 624                 nn->m_next = NULL;
 625                 n->m_next = nn;
 626                 n = nn;
 627                 m->m_pkthdr.len += extendsiz;
 628         }
 629         switch (sav->flags & SADB_X_EXT_PMASK) {
 630         case SADB_X_EXT_PRAND:
 631                 key_randomfill(extend, extendsiz);
 632                 break;
 633         case SADB_X_EXT_PZERO:
 634                 bzero(extend, extendsiz);
 635                 break;
 636         case SADB_X_EXT_PSEQ:
 637                 for (i = 0; i < extendsiz; i++)
 638                         extend[i] = (i + 1) & 0xff;
 639                 break;
 640         }
 641
 642         nxt = *nexthdrp;
 643         if (udp_encapsulate) {
 644                 *nexthdrp = IPPROTO_UDP;
 645
 646                 /* Fill out the UDP header */
 647                 udp->uh_sport = ntohs((u_short)esp_udp_encap_port);
 648                 udp->uh_dport = ntohs(sav->remote_ike_port);
 649 //              udp->uh_len set later, after all length tweaks are complete
 650                 udp->uh_sum = 0;
 651
 652                 /* Update last sent so we know if we need to send keepalive */
 653                 sav->natt_last_activity = natt_now;
 654         } else {
 655                 *nexthdrp = IPPROTO_ESP;
 656         }
 657
 658         /* initialize esp trailer. */
 659         esptail = (struct esptail *)
 660                 (mtod(n, u_int8_t *) + n->m_len - sizeof(struct esptail));
 661         esptail->esp_nxt = nxt;
 662         esptail->esp_padlen = extendsiz - 2;
 663
 664         /* modify IP header (for ESP header part only) */
 665         switch (af) {
 666 #if INET
 667         case AF_INET:
 668                 ip = mtod(m, struct ip *);
 669                 if (extendsiz < (IP_MAXPACKET - ntohs(ip->ip_len)))
 670                         ip->ip_len = htons(ntohs(ip->ip_len) + extendsiz);
 671                 else {
 672                         ipseclog((LOG_ERR,
 673                             "IPv4 ESP output: size exceeds limit\n"));
 674                         IPSEC_STAT_INCREMENT(ipsecstat.out_inval);
 675                         m_freem(m);
 676                         error = EMSGSIZE;
 677                         goto fail;
 678                 }
 679                 break;
 680 #endif
 681 #if INET6
 682         case AF_INET6:
 683                 /* total packet length will be computed in ip6_output() */
 684                 break;
 685 #endif
 686         }
 687     }
 688
 689         /*
 690          * pre-compute and cache intermediate key
 691          */
 692         error = esp_schedule(algo, sav);
 693         if (error) {
 694                 m_freem(m);
 695                 IPSEC_STAT_INCREMENT(stat->out_inval);
 696                 goto fail;
 697         }
 698
 699         /*
 700          * encrypt the packet, based on security association
 701          * and the algorithm specified.
 702          */
 703         if (!algo->encrypt)
 704                 panic("internal error: no encrypt function");
 705         KERNEL_DEBUG(DBG_FNC_ENCRYPT | DBG_FUNC_START, 0,0,0,0,0);
 706         if ((*algo->encrypt)(m, espoff, plen + extendsiz, sav, algo, ivlen)) {
 707                 /* m is already freed */
 708                 ipseclog((LOG_ERR, "packet encryption failure\n"));
 709                 IPSEC_STAT_INCREMENT(stat->out_inval);
 710                 error = EINVAL;
 711                 KERNEL_DEBUG(DBG_FNC_ENCRYPT | DBG_FUNC_END, 1,error,0,0,0);
 712                 goto fail;
 713         }
 714         KERNEL_DEBUG(DBG_FNC_ENCRYPT | DBG_FUNC_END, 2,0,0,0,0);
 715
 716         /*
 717          * calculate ICV if required.
 718          */
 719         size_t siz = 0;
 720         u_char authbuf[AH_MAXSUMSIZE] __attribute__((aligned(4)));
 721
 722         if (algo->finalizeencrypt) {
 723                 siz = algo->icvlen;
 724                 if ((*algo->finalizeencrypt)(sav, authbuf, siz)) {
 725                         ipseclog((LOG_ERR, "packet encryption ICV failure\n"));
 726                         IPSEC_STAT_INCREMENT(stat->out_inval);
 727                         error = EINVAL;
 728                         KERNEL_DEBUG(DBG_FNC_ENCRYPT | DBG_FUNC_END, 1,error,0,0,0);
 729                         goto fail;
 730                 }
 731                 goto fill_icv;
 732         }
 733
 734         if (!sav->replay)
 735                 goto noantireplay;
 736         if (!sav->key_auth)
 737                 goto noantireplay;
 738         if (sav->key_auth == SADB_AALG_NONE)
 739                 goto noantireplay;
 740
 741     {
 742                 const struct ah_algorithm *aalgo;
 743
 744                 aalgo = ah_algorithm_lookup(sav->alg_auth);
 745                 if (!aalgo)
 746                         goto noantireplay;
 747                 siz = ((aalgo->sumsiz)(sav) + 3) & ~(4 - 1);
 748                 if (AH_MAXSUMSIZE < siz)
 749                         panic("assertion failed for AH_MAXSUMSIZE");
 750
 751                 if (esp_auth(m, espoff, m->m_pkthdr.len - espoff, sav, authbuf)) {
 752                         ipseclog((LOG_ERR, "ESP checksum generation failure\n"));
 753                         m_freem(m);
 754                         error = EINVAL;
 755                         IPSEC_STAT_INCREMENT(stat->out_inval);
 756                         goto fail;
 757                 }
 758     }
 759
 760  fill_icv:
 761     {
 762                 struct ip *ip;
 763                 u_char *p;
 764
 765                 n = m;
 766                 while (n->m_next)
 767                         n = n->m_next;
 768
 769                 if (!(n->m_flags & M_EXT) && siz < M_TRAILINGSPACE(n)) { /* XXX */
 770                         n->m_len += siz;
 771                         m->m_pkthdr.len += siz;
 772                         p = mtod(n, u_char *) + n->m_len - siz;
 773                 } else {
 774                         struct mbuf *nn;
 775
 776                         MGET(nn, M_DONTWAIT, MT_DATA);
 777                         if (!nn) {
 778                                 ipseclog((LOG_DEBUG, "can't alloc mbuf in esp%d_output",
 779                                         afnumber));
 780                                 m_freem(m);
 781                                 error = ENOBUFS;
 782                                 goto fail;
 783                         }
 784                         nn->m_len = siz;
 785                         nn->m_next = NULL;
 786                         n->m_next = nn;
 787                         n = nn;
 788                         m->m_pkthdr.len += siz;
 789                         p = mtod(nn, u_char *);
 790                 }
 791                 bcopy(authbuf, p, siz);
 792
 793                 /* modify IP header (for ESP header part only) */
 794                 switch (af) {
 795         #if INET
 796                 case AF_INET:
 797                         ip = mtod(m, struct ip *);
 798                         if (siz < (IP_MAXPACKET - ntohs(ip->ip_len)))
 799                                 ip->ip_len = htons(ntohs(ip->ip_len) + siz);
 800                         else {
 801                                 ipseclog((LOG_ERR,
 802                                         "IPv4 ESP output: size exceeds limit\n"));
 803                                 IPSEC_STAT_INCREMENT(ipsecstat.out_inval);
 804                                 m_freem(m);
 805                                 error = EMSGSIZE;
 806                                 goto fail;
 807                         }
 808                         break;
 809         #endif
 810         #if INET6
 811                 case AF_INET6:
 812                         /* total packet length will be computed in ip6_output() */
 813                         break;
 814         #endif
 815                 }
 816     }
 817
 818         if (udp_encapsulate) {
 819                 struct ip *ip;
 820                 struct ip6_hdr *ip6;
 821
 822                 switch (af) {
 823                 case AF_INET:
 824                     ip = mtod(m, struct ip *);
 825                     udp->uh_ulen = htons(ntohs(ip->ip_len) - (IP_VHL_HL(ip->ip_vhl) << 2));
 826                     break;
 827                 case AF_INET6:
 828                     ip6 = mtod(m, struct ip6_hdr *);
 829                     udp->uh_ulen = htons(plen + siz + extendsiz + esphlen);
 830                     udp->uh_sum = in6_pseudo(&ip6->ip6_src, &ip6->ip6_dst, htonl(ntohs(udp->uh_ulen) + IPPROTO_UDP));
 831                     m->m_pkthdr.csum_flags = CSUM_UDPIPV6;
 832                     m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
 833                     break;
 834                 }
 835         }
 836
 837 noantireplay:
 838         lck_mtx_lock(sadb_mutex);
 839         if (!m) {
 840                 ipseclog((LOG_ERR,
 841                     "NULL mbuf after encryption in esp%d_output", afnumber));
 842         } else
 843                 stat->out_success++;
 844         stat->out_esphist[sav->alg_enc]++;
 845         lck_mtx_unlock(sadb_mutex);
 846         key_sa_recordxfer(sav, m);
 847         KERNEL_DEBUG(DBG_FNC_ESPOUT | DBG_FUNC_END, 6,0,0,0,0);
 848         return 0;
 849
 850 fail:
 851 #if 1
 852         KERNEL_DEBUG(DBG_FNC_ESPOUT | DBG_FUNC_END, 7,error,0,0,0);
 853         return error;
 854 #else
 855         panic("something bad in esp_output");
 856 #endif
 857 }
 858
 859 #if INET
 860 int
 861 esp4_output(
 862         struct mbuf *m,
 863         struct secasvar *sav)
 864 {
 865         struct ip *ip;
 866         if (m->m_len < sizeof(struct ip)) {
 867                 ipseclog((LOG_DEBUG, "esp4_output: first mbuf too short\n"));
 868                 m_freem(m);
 869                 return EINVAL;
 870         }
 871         ip = mtod(m, struct ip *);
 872         /* XXX assumes that m->m_next points to payload */
 873         return esp_output(m, &ip->ip_p, m->m_next, AF_INET, sav);
 874 }
 875 #endif /*INET*/
 876
 877 #if INET6
 878 int
 879 esp6_output(
 880         struct mbuf *m,
 881         u_char *nexthdrp,
 882         struct mbuf *md,
 883         struct secasvar *sav)
 884 {
 885         if (m->m_len < sizeof(struct ip6_hdr)) {
 886                 ipseclog((LOG_DEBUG, "esp6_output: first mbuf too short\n"));
 887                 m_freem(m);
 888                 return EINVAL;
 889         }
 890         return esp_output(m, nexthdrp, md, AF_INET6, sav);
 891 }
 892 #endif /*INET6*/