sys/netproto/ipsec/xform_esp.c

   1 /*      $FreeBSD: src/sys/netipsec/xform_esp.c,v 1.2.2.2 2003/02/26 00:14:05 sam Exp $  */
   2 /*      $DragonFly: src/sys/netproto/ipsec/xform_esp.c,v 1.13 2008/01/06 16:55:52 swildner Exp $        */
   3 /*      $OpenBSD: ip_esp.c,v 1.69 2001/06/26 06:18:59 angelos Exp $ */
   4 /*
   5  * The authors of this code are John Ioannidis (ji@tla.org),
   6  * Angelos D. Keromytis (kermit@csd.uch.gr) and
   7  * Niels Provos (provos@physnet.uni-hamburg.de).
   8  *
   9  * The original version of this code was written by John Ioannidis
  10  * for BSD/OS in Athens, Greece, in November 1995.
  11  *
  12  * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
  13  * by Angelos D. Keromytis.
  14  *
  15  * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
  16  * and Niels Provos.
  17  *
  18  * Additional features in 1999 by Angelos D. Keromytis.
  19  *
  20  * Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
  21  * Angelos D. Keromytis and Niels Provos.
  22  * Copyright (c) 2001 Angelos D. Keromytis.
  23  *
  24  * Permission to use, copy, and modify this software with or without fee
  25  * is hereby granted, provided that this entire notice is included in
  26  * all copies of any software which is or includes a copy or
  27  * modification of this software.
  28  * You may use this code under the GNU public license if you so wish. Please
  29  * contribute changes back to the authors under this freer than GPL license
  30  * so that we may further the use of strong encryption without limitations to
  31  * all.
  32  *
  33  * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
  34  * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
  35  * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
  36  * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
  37  * PURPOSE.
  38  */
  39 #include "opt_inet.h"
  40 #include "opt_inet6.h"
  41
  42 #include <sys/param.h>
  43 #include <sys/systm.h>
  44 #include <sys/mbuf.h>
  45 #include <sys/socket.h>
  46 #include <sys/syslog.h>
  47 #include <sys/kernel.h>
  48 #include <sys/random.h>
  49 #include <sys/sysctl.h>
  50
  51 #include <net/if.h>
  52
  53 #include <netinet/in.h>
  54 #include <netinet/in_systm.h>
  55 #include <netinet/ip.h>
  56 #include <netinet/ip_ecn.h>
  57 #include <netinet/ip6.h>
  58
  59 #include <net/route.h>
  60 #include <netproto/ipsec/ipsec.h>
  61 #include <netproto/ipsec/ah.h>
  62 #include <netproto/ipsec/ah_var.h>
  63 #include <netproto/ipsec/esp.h>
  64 #include <netproto/ipsec/esp_var.h>
  65 #include <netproto/ipsec/xform.h>
  66
  67 #ifdef INET6
  68 #include <netinet6/ip6_var.h>
  69 #include <netproto/ipsec/ipsec6.h>
  70 #include <netinet6/ip6_ecn.h>
  71 #endif
  72
  73 #include <netproto/ipsec/key.h>
  74 #include <netproto/ipsec/key_debug.h>
  75
  76 #include <opencrypto/cryptodev.h>
  77 #include <opencrypto/xform.h>
  78
  79 int     esp_enable = 1;
  80 struct  espstat espstat;
  81
  82 SYSCTL_DECL(_net_inet_esp);
  83 SYSCTL_INT(_net_inet_esp, OID_AUTO,
  84         esp_enable,     CTLFLAG_RW,     &esp_enable,    0, "");
  85 SYSCTL_STRUCT(_net_inet_esp, IPSECCTL_STATS,
  86         stats,          CTLFLAG_RD,     &espstat,       espstat, "");
  87
  88 static  int esp_max_ivlen;              /* max iv length over all algorithms */
  89
  90 static int esp_input_cb(struct cryptop *op);
  91 static int esp_output_cb(struct cryptop *crp);
  92
  93 /*
  94  * NB: this is public for use by the PF_KEY support.
  95  * NB: if you add support here; be sure to add code to esp_attach below!
  96  */
  97 struct enc_xform *
  98 esp_algorithm_lookup(int alg)
  99 {
 100         if (alg >= ESP_ALG_MAX)
 101                 return NULL;
 102         switch (alg) {
 103         case SADB_EALG_DESCBC:
 104                 return &enc_xform_des;
 105         case SADB_EALG_3DESCBC:
 106                 return &enc_xform_3des;
 107         case SADB_X_EALG_AES:
 108                 return &enc_xform_rijndael128;
 109         case SADB_X_EALG_BLOWFISHCBC:
 110                 return &enc_xform_blf;
 111         case SADB_X_EALG_CAST128CBC:
 112                 return &enc_xform_cast5;
 113         case SADB_X_EALG_SKIPJACK:
 114                 return &enc_xform_skipjack;
 115         case SADB_EALG_NULL:
 116                 return &enc_xform_null;
 117         }
 118         return NULL;
 119 }
 120
 121 size_t
 122 esp_hdrsiz(struct secasvar *sav)
 123 {
 124         size_t size;
 125
 126         if (sav != NULL) {
 127                 /*XXX not right for null algorithm--does it matter??*/
 128                 KASSERT(sav->tdb_encalgxform != NULL,
 129                         ("esp_hdrsiz: SA with null xform"));
 130                 if (sav->flags & SADB_X_EXT_OLD)
 131                         size = sizeof (struct esp);
 132                 else
 133                         size = sizeof (struct newesp);
 134                 size += sav->tdb_encalgxform->blocksize + 9;
 135                 /*XXX need alg check???*/
 136                 if (sav->tdb_authalgxform != NULL && sav->replay)
 137                         size += ah_hdrsiz(sav);
 138         } else {
 139                 /*
 140                  *   base header size
 141                  * + max iv length for CBC mode
 142                  * + max pad length
 143                  * + sizeof (pad length field)
 144                  * + sizeof (next header field)
 145                  * + max icv supported.
 146                  */
 147                 size = sizeof (struct newesp) + esp_max_ivlen + 9 + 16;
 148         }
 149         return size;
 150 }
 151
 152 /*
 153  * esp_init() is called when an SPI is being set up.
 154  */
 155 static int
 156 esp_init(struct secasvar *sav, struct xformsw *xsp)
 157 {
 158         struct enc_xform *txform;
 159         struct cryptoini cria, crie;
 160         int keylen;
 161         int error;
 162
 163         txform = esp_algorithm_lookup(sav->alg_enc);
 164         if (txform == NULL) {
 165                 DPRINTF(("esp_init: unsupported encryption algorithm %d\n",
 166                         sav->alg_enc));
 167                 return EINVAL;
 168         }
 169         if (sav->key_enc == NULL) {
 170                 DPRINTF(("esp_init: no encoding key for %s algorithm\n",
 171                          txform->name));
 172                 return EINVAL;
 173         }
 174         if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) {
 175                 DPRINTF(("esp_init: 4-byte IV not supported with protocol\n"));
 176                 return EINVAL;
 177         }
 178         keylen = _KEYLEN(sav->key_enc);
 179         if (txform->minkey > keylen || keylen > txform->maxkey) {
 180                 DPRINTF(("esp_init: invalid key length %u, must be in "
 181                         "the range [%u..%u] for algorithm %s\n",
 182                         keylen, txform->minkey, txform->maxkey,
 183                         txform->name));
 184                 return EINVAL;
 185         }
 186
 187         /*
 188          * NB: The null xform needs a non-zero blocksize to keep the
 189          *      crypto code happy but if we use it to set ivlen then
 190          *      the ESP header will be processed incorrectly.  The
 191          *      compromise is to force it to zero here.
 192          */
 193         sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize);
 194         sav->iv = (caddr_t) kmalloc(sav->ivlen, M_XDATA, M_WAITOK);
 195         key_randomfill(sav->iv, sav->ivlen);    /*XXX*/
 196
 197         /*
 198          * Setup AH-related state.
 199          */
 200         if (sav->alg_auth != 0) {
 201                 error = ah_init0(sav, xsp, &cria);
 202                 if (error)
 203                         return error;
 204         }
 205
 206         /* NB: override anything set in ah_init0 */
 207         sav->tdb_xform = xsp;
 208         sav->tdb_encalgxform = txform;
 209
 210         /* Initialize crypto session. */
 211         bzero(&crie, sizeof (crie));
 212         crie.cri_alg = sav->tdb_encalgxform->type;
 213         crie.cri_klen = _KEYBITS(sav->key_enc);
 214         crie.cri_key = _KEYBUF(sav->key_enc);
 215         /* XXX Rounds ? */
 216
 217         if (sav->tdb_authalgxform && sav->tdb_encalgxform) {
 218                 /* init both auth & enc */
 219                 crie.cri_next = &cria;
 220                 error = crypto_newsession(&sav->tdb_cryptoid,
 221                                           &crie, crypto_support);
 222         } else if (sav->tdb_encalgxform) {
 223                 error = crypto_newsession(&sav->tdb_cryptoid,
 224                                           &crie, crypto_support);
 225         } else if (sav->tdb_authalgxform) {
 226                 error = crypto_newsession(&sav->tdb_cryptoid,
 227                                           &cria, crypto_support);
 228         } else {
 229                 /* XXX cannot happen? */
 230                 DPRINTF(("esp_init: no encoding OR authentication xform!\n"));
 231                 error = EINVAL;
 232         }
 233         return error;
 234 }
 235
 236 /*
 237  * Paranoia.
 238  */
 239 static int
 240 esp_zeroize(struct secasvar *sav)
 241 {
 242         /* NB: ah_zerorize free's the crypto session state */
 243         int error = ah_zeroize(sav);
 244
 245         if (sav->key_enc)
 246                 bzero(_KEYBUF(sav->key_enc), _KEYLEN(sav->key_enc));
 247         /* NB: sav->iv is freed elsewhere, even though we malloc it! */
 248         sav->tdb_encalgxform = NULL;
 249         sav->tdb_xform = NULL;
 250         return error;
 251 }
 252
 253 /*
 254  * ESP input processing, called (eventually) through the protocol switch.
 255  */
 256 static int
 257 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
 258 {
 259         struct auth_hash *esph;
 260         struct enc_xform *espx;
 261         struct tdb_ident *tdbi;
 262         struct tdb_crypto *tc;
 263         int plen, alen, hlen;
 264         struct m_tag *mtag;
 265         struct newesp *esp;
 266
 267         struct cryptodesc *crde;
 268         struct cryptop *crp;
 269
 270         KASSERT(sav != NULL, ("esp_input: null SA"));
 271         KASSERT(sav->tdb_encalgxform != NULL,
 272                 ("esp_input: null encoding xform"));
 273         KASSERT((skip&3) == 0 && (m->m_pkthdr.len&3) == 0,
 274                 ("esp_input: misaligned packet, skip %u pkt len %u",
 275                         skip, m->m_pkthdr.len));
 276
 277         /* XXX don't pullup, just copy header */
 278         IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp));
 279
 280         esph = sav->tdb_authalgxform;
 281         espx = sav->tdb_encalgxform;
 282
 283         /* Determine the ESP header length */
 284         if (sav->flags & SADB_X_EXT_OLD)
 285                 hlen = sizeof (struct esp) + sav->ivlen;
 286         else
 287                 hlen = sizeof (struct newesp) + sav->ivlen;
 288         /* Authenticator hash size */
 289         alen = esph ? AH_HMAC_HASHLEN : 0;
 290
 291         /*
 292          * Verify payload length is multiple of encryption algorithm
 293          * block size.
 294          *
 295          * NB: This works for the null algorithm because the blocksize
 296          *     is 4 and all packets must be 4-byte aligned regardless
 297          *     of the algorithm.
 298          */
 299         plen = m->m_pkthdr.len - (skip + hlen + alen);
 300         if ((plen & (espx->blocksize - 1)) || (plen <= 0)) {
 301                 DPRINTF(("esp_input: "
 302                     "payload of %d octets not a multiple of %d octets,"
 303                     "  SA %s/%08lx\n",
 304                     plen, espx->blocksize,
 305                     ipsec_address(&sav->sah->saidx.dst),
 306                     (u_long) ntohl(sav->spi)));
 307                 espstat.esps_badilen++;
 308                 m_freem(m);
 309                 return EINVAL;
 310         }
 311
 312         /*
 313          * Check sequence number.
 314          */
 315         if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) {
 316                 DPRINTF(("esp_input: packet replay check for %s\n",
 317                     ipsec_logsastr(sav)));      /*XXX*/
 318                 espstat.esps_replay++;
 319                 m_freem(m);
 320                 return ENOBUFS;         /*XXX*/
 321         }
 322
 323         /* Update the counters */
 324         espstat.esps_ibytes += m->m_pkthdr.len - skip - hlen - alen;
 325
 326         /* Find out if we've already done crypto */
 327         for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL);
 328              mtag != NULL;
 329              mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) {
 330                 tdbi = (struct tdb_ident *)m_tag_data(mtag);
 331                 if (tdbi->proto == sav->sah->saidx.proto &&
 332                     tdbi->spi == sav->spi &&
 333                     !bcmp(&tdbi->dst, &sav->sah->saidx.dst,
 334                           sizeof(union sockaddr_union)))
 335                         break;
 336         }
 337
 338         /* Get crypto descriptors */
 339         crp = crypto_getreq(esph && espx ? 2 : 1);
 340         if (crp == NULL) {
 341                 DPRINTF(("esp_input: failed to acquire crypto descriptors\n"));
 342                 espstat.esps_crypto++;
 343                 m_freem(m);
 344                 return ENOBUFS;
 345         }
 346
 347         /* Get IPsec-specific opaque pointer */
 348         if (esph == NULL || mtag != NULL)
 349                 tc = kmalloc(sizeof(struct tdb_crypto),
 350                             M_XDATA, M_INTWAIT | M_ZERO | M_NULLOK);
 351         else
 352                 tc = kmalloc(sizeof(struct tdb_crypto) + alen,
 353                             M_XDATA, M_INTWAIT | M_ZERO | M_NULLOK);
 354         if (tc == NULL) {
 355                 crypto_freereq(crp);
 356                 DPRINTF(("esp_input: failed to allocate tdb_crypto\n"));
 357                 espstat.esps_crypto++;
 358                 m_freem(m);
 359                 return ENOBUFS;
 360         }
 361
 362         tc->tc_ptr = (caddr_t) mtag;
 363
 364         if (esph) {
 365                 struct cryptodesc *crda = crp->crp_desc;
 366
 367                 KASSERT(crda != NULL, ("esp_input: null ah crypto descriptor"));
 368
 369                 /* Authentication descriptor */
 370                 crda->crd_skip = skip;
 371                 crda->crd_len = m->m_pkthdr.len - (skip + alen);
 372                 crda->crd_inject = m->m_pkthdr.len - alen;
 373
 374                 crda->crd_alg = esph->type;
 375                 crda->crd_key = _KEYBUF(sav->key_auth);
 376                 crda->crd_klen = _KEYBITS(sav->key_auth);
 377
 378                 /* Copy the authenticator */
 379                 if (mtag == NULL)
 380                         m_copydata(m, m->m_pkthdr.len - alen, alen,
 381                                    (caddr_t) (tc + 1));
 382
 383                 /* Chain authentication request */
 384                 crde = crda->crd_next;
 385         } else {
 386                 crde = crp->crp_desc;
 387         }
 388
 389         /* Crypto operation descriptor */
 390         crp->crp_ilen = m->m_pkthdr.len; /* Total input length */
 391         crp->crp_flags = CRYPTO_F_IMBUF;
 392         crp->crp_buf = (caddr_t) m;
 393         crp->crp_callback = esp_input_cb;
 394         crp->crp_sid = sav->tdb_cryptoid;
 395         crp->crp_opaque = (caddr_t) tc;
 396
 397         /* These are passed as-is to the callback */
 398         tc->tc_spi = sav->spi;
 399         tc->tc_dst = sav->sah->saidx.dst;
 400         tc->tc_proto = sav->sah->saidx.proto;
 401         tc->tc_protoff = protoff;
 402         tc->tc_skip = skip;
 403
 404         /* Decryption descriptor */
 405         if (espx) {
 406                 KASSERT(crde != NULL, ("esp_input: null esp crypto descriptor"));
 407                 crde->crd_skip = skip + hlen;
 408                 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
 409                 crde->crd_inject = skip + hlen - sav->ivlen;
 410
 411                 crde->crd_alg = espx->type;
 412                 crde->crd_key = _KEYBUF(sav->key_enc);
 413                 crde->crd_klen = _KEYBITS(sav->key_enc);
 414                 /* XXX Rounds ? */
 415         }
 416
 417         if (mtag == NULL)
 418                 return crypto_dispatch(crp);
 419         else
 420                 return esp_input_cb(crp);
 421 }
 422
 423 #ifdef INET6
 424 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do {              \
 425         if (saidx->dst.sa.sa_family == AF_INET6) {                           \
 426                 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \
 427         } else {                                                             \
 428                 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \
 429         }                                                                    \
 430 } while (0)
 431 #else
 432 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag)                   \
 433         (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag))
 434 #endif
 435
 436 /*
 437  * ESP input callback from the crypto driver.
 438  */
 439 static int
 440 esp_input_cb(struct cryptop *crp)
 441 {
 442         u_int8_t lastthree[3], aalg[AH_HMAC_HASHLEN];
 443         int hlen, skip, protoff, error;
 444         struct mbuf *m;
 445         struct cryptodesc *crd;
 446         struct auth_hash *esph;
 447         struct enc_xform *espx;
 448         struct tdb_crypto *tc;
 449         struct m_tag *mtag;
 450         struct secasvar *sav;
 451         struct secasindex *saidx;
 452         caddr_t ptr;
 453
 454         crd = crp->crp_desc;
 455         KASSERT(crd != NULL, ("esp_input_cb: null crypto descriptor!"));
 456
 457         tc = (struct tdb_crypto *) crp->crp_opaque;
 458         KASSERT(tc != NULL, ("esp_input_cb: null opaque crypto data area!"));
 459         skip = tc->tc_skip;
 460         protoff = tc->tc_protoff;
 461         mtag = (struct m_tag *) tc->tc_ptr;
 462         m = (struct mbuf *) crp->crp_buf;
 463
 464         crit_enter();
 465
 466         sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi);
 467         if (sav == NULL) {
 468                 espstat.esps_notdb++;
 469                 DPRINTF(("esp_input_cb: SA expired while in crypto "
 470                     "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst),
 471                     (u_long) ntohl(tc->tc_spi), tc->tc_proto));
 472                 error = ENOBUFS;                /*XXX*/
 473                 goto bad;
 474         }
 475
 476         saidx = &sav->sah->saidx;
 477         KASSERT(saidx->dst.sa.sa_family == AF_INET ||
 478                 saidx->dst.sa.sa_family == AF_INET6,
 479                 ("ah_input_cb: unexpected protocol family %u",
 480                  saidx->dst.sa.sa_family));
 481
 482         esph = sav->tdb_authalgxform;
 483         espx = sav->tdb_encalgxform;
 484
 485         /* Check for crypto errors */
 486         if (crp->crp_etype) {
 487                 /* Reset the session ID */
 488                 if (sav->tdb_cryptoid != 0)
 489                         sav->tdb_cryptoid = crp->crp_sid;
 490
 491                 if (crp->crp_etype == EAGAIN) {
 492                         KEY_FREESAV(&sav);
 493                         crit_exit();
 494                         return crypto_dispatch(crp);
 495                 }
 496
 497                 espstat.esps_noxform++;
 498                 DPRINTF(("esp_input_cb: crypto error %d\n", crp->crp_etype));
 499                 error = crp->crp_etype;
 500                 goto bad;
 501         }
 502
 503         /* Shouldn't happen... */
 504         if (m == NULL) {
 505                 espstat.esps_crypto++;
 506                 DPRINTF(("esp_input_cb: bogus returned buffer from crypto\n"));
 507                 error = EINVAL;
 508                 goto bad;
 509         }
 510         espstat.esps_hist[sav->alg_enc]++;
 511
 512         /* If authentication was performed, check now. */
 513         if (esph != NULL) {
 514                 /*
 515                  * If we have a tag, it means an IPsec-aware NIC did
 516                  * the verification for us.  Otherwise we need to
 517                  * check the authentication calculation.
 518                  */
 519                 ahstat.ahs_hist[sav->alg_auth]++;
 520                 if (mtag == NULL) {
 521                         /* Copy the authenticator from the packet */
 522                         m_copydata(m, m->m_pkthdr.len - esph->authsize,
 523                                 esph->authsize, aalg);
 524
 525                         ptr = (caddr_t) (tc + 1);
 526
 527                         /* Verify authenticator */
 528                         if (bcmp(ptr, aalg, esph->authsize) != 0) {
 529                                 DPRINTF(("esp_input_cb: "
 530                     "authentication hash mismatch for packet in SA %s/%08lx\n",
 531                                     ipsec_address(&saidx->dst),
 532                                     (u_long) ntohl(sav->spi)));
 533                                 espstat.esps_badauth++;
 534                                 error = EACCES;
 535                                 goto bad;
 536                         }
 537                 }
 538
 539                 /* Remove trailing authenticator */
 540                 m_adj(m, -(esph->authsize));
 541         }
 542
 543         /* Release the crypto descriptors */
 544         kfree(tc, M_XDATA), tc = NULL;
 545         crypto_freereq(crp), crp = NULL;
 546
 547         /*
 548          * Packet is now decrypted.
 549          */
 550         m->m_flags |= M_DECRYPTED;
 551
 552         /*
 553          * Update replay sequence number, if appropriate.
 554          */
 555         if (sav->replay) {
 556                 u_int32_t seq;
 557
 558                 m_copydata(m, skip + offsetof(struct newesp, esp_seq),
 559                            sizeof (seq), (caddr_t) &seq);
 560                 if (ipsec_updatereplay(ntohl(seq), sav)) {
 561                         DPRINTF(("%s: packet replay check for %s\n", __func__,
 562                             ipsec_logsastr(sav)));
 563                         espstat.esps_replay++;
 564                         error = ENOBUFS;
 565                         goto bad;
 566                 }
 567         }
 568
 569         /* Determine the ESP header length */
 570         if (sav->flags & SADB_X_EXT_OLD)
 571                 hlen = sizeof (struct esp) + sav->ivlen;
 572         else
 573                 hlen = sizeof (struct newesp) + sav->ivlen;
 574
 575         /* Remove the ESP header and IV from the mbuf. */
 576         error = m_striphdr(m, skip, hlen);
 577         if (error) {
 578                 espstat.esps_hdrops++;
 579                 DPRINTF(("esp_input_cb: bad mbuf chain, SA %s/%08lx\n",
 580                     ipsec_address(&sav->sah->saidx.dst),
 581                     (u_long) ntohl(sav->spi)));
 582                 goto bad;
 583         }
 584
 585         /* Save the last three bytes of decrypted data */
 586         m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree);
 587
 588         /* Verify pad length */
 589         if (lastthree[1] + 2 > m->m_pkthdr.len - skip) {
 590                 espstat.esps_badilen++;
 591                 DPRINTF(("esp_input_cb: invalid padding length %d "
 592                          "for %u byte packet in SA %s/%08lx\n",
 593                          lastthree[1], m->m_pkthdr.len - skip,
 594                          ipsec_address(&sav->sah->saidx.dst),
 595                          (u_long) ntohl(sav->spi)));
 596                 error = EINVAL;
 597                 goto bad;
 598         }
 599
 600         /* Verify correct decryption by checking the last padding bytes */
 601         if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) {
 602                 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) {
 603                         espstat.esps_badenc++;
 604                         DPRINTF(("esp_input_cb: decryption failed "
 605                                 "for packet in SA %s/%08lx\n",
 606                                 ipsec_address(&sav->sah->saidx.dst),
 607                                 (u_long) ntohl(sav->spi)));
 608 DPRINTF(("esp_input_cb: %x %x\n", lastthree[0], lastthree[1]));
 609                         error = EINVAL;
 610                         goto bad;
 611                 }
 612         }
 613
 614         /* Trim the mbuf chain to remove trailing authenticator and padding */
 615         m_adj(m, -(lastthree[1] + 2));
 616
 617         /* Restore the Next Protocol field */
 618         m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2);
 619
 620         IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag);
 621
 622         KEY_FREESAV(&sav);
 623         crit_exit();
 624         return error;
 625 bad:
 626         if (sav)
 627                 KEY_FREESAV(&sav);
 628         crit_exit();
 629         if (m != NULL)
 630                 m_freem(m);
 631         if (tc != NULL)
 632                 kfree(tc, M_XDATA);
 633         if (crp != NULL)
 634                 crypto_freereq(crp);
 635         return error;
 636 }
 637
 638 /*
 639  * ESP output routine, called by ipsec[46]_process_packet().
 640  */
 641 static int
 642 esp_output(
 643         struct mbuf *m,
 644         struct ipsecrequest *isr,
 645         struct mbuf **mp,
 646         int skip,
 647         int protoff
 648 )
 649 {
 650         struct enc_xform *espx;
 651         struct auth_hash *esph;
 652         int hlen, rlen, plen, padding, blks, alen, i, roff;
 653         struct mbuf *mo = (struct mbuf *) NULL;
 654         struct tdb_crypto *tc;
 655         struct secasvar *sav;
 656         struct secasindex *saidx;
 657         unsigned char *pad;
 658         u_int8_t prot;
 659         int error, maxpacketsize;
 660
 661         struct cryptodesc *crde = NULL, *crda = NULL;
 662         struct cryptop *crp;
 663
 664         sav = isr->sav;
 665         KASSERT(sav != NULL, ("esp_output: null SA"));
 666         esph = sav->tdb_authalgxform;
 667         espx = sav->tdb_encalgxform;
 668         KASSERT(espx != NULL, ("esp_output: null encoding xform"));
 669
 670         if (sav->flags & SADB_X_EXT_OLD)
 671                 hlen = sizeof (struct esp) + sav->ivlen;
 672         else
 673                 hlen = sizeof (struct newesp) + sav->ivlen;
 674
 675         rlen = m->m_pkthdr.len - skip;  /* Raw payload length. */
 676         /*
 677          * NB: The null encoding transform has a blocksize of 4
 678          *     so that headers are properly aligned.
 679          */
 680         blks = espx->blocksize;         /* IV blocksize */
 681
 682         /* XXX clamp padding length a la KAME??? */
 683         padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;
 684         plen = rlen + padding;          /* Padded payload length. */
 685
 686         if (esph)
 687                 alen = AH_HMAC_HASHLEN;
 688         else
 689                 alen = 0;
 690
 691         espstat.esps_output++;
 692
 693         saidx = &sav->sah->saidx;
 694         /* Check for maximum packet size violations. */
 695         switch (saidx->dst.sa.sa_family) {
 696 #ifdef INET
 697         case AF_INET:
 698                 maxpacketsize = IP_MAXPACKET;
 699                 break;
 700 #endif /* INET */
 701 #ifdef INET6
 702         case AF_INET6:
 703                 maxpacketsize = IPV6_MAXPACKET;
 704                 break;
 705 #endif /* INET6 */
 706         default:
 707                 DPRINTF(("esp_output: unknown/unsupported protocol "
 708                     "family %d, SA %s/%08lx\n",
 709                     saidx->dst.sa.sa_family, ipsec_address(&saidx->dst),
 710                     (u_long) ntohl(sav->spi)));
 711                 espstat.esps_nopf++;
 712                 error = EPFNOSUPPORT;
 713                 goto bad;
 714         }
 715         if (skip + hlen + rlen + padding + alen > maxpacketsize) {
 716                 DPRINTF(("esp_output: packet in SA %s/%08lx got too big "
 717                     "(len %u, max len %u)\n",
 718                     ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi),
 719                     skip + hlen + rlen + padding + alen, maxpacketsize));
 720                 espstat.esps_toobig++;
 721                 error = EMSGSIZE;
 722                 goto bad;
 723         }
 724
 725         /* Update the counters. */
 726         espstat.esps_obytes += m->m_pkthdr.len - skip;
 727
 728         m = m_clone(m);
 729         if (m == NULL) {
 730                 DPRINTF(("esp_output: cannot clone mbuf chain, SA %s/%08lx\n",
 731                     ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
 732                 espstat.esps_hdrops++;
 733                 error = ENOBUFS;
 734                 goto bad;
 735         }
 736
 737         /* Inject ESP header. */
 738         mo = m_makespace(m, skip, hlen, &roff);
 739         if (mo == NULL) {
 740                 DPRINTF(("esp_output: failed to inject %u byte ESP hdr for SA "
 741                     "%s/%08lx\n",
 742                     hlen, ipsec_address(&saidx->dst),
 743                     (u_long) ntohl(sav->spi)));
 744                 espstat.esps_hdrops++;          /* XXX diffs from openbsd */
 745                 error = ENOBUFS;
 746                 goto bad;
 747         }
 748
 749         /* Initialize ESP header. */
 750         bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t));
 751         if (sav->replay) {
 752                 u_int32_t replay = htonl(++(sav->replay->count));
 753                 bcopy((caddr_t) &replay,
 754                     mtod(mo, caddr_t) + roff + sizeof(u_int32_t),
 755                     sizeof(u_int32_t));
 756         }
 757
 758         /*
 759          * Add padding -- better to do it ourselves than use the crypto engine,
 760          * although if/when we support compression, we'd have to do that.
 761          */
 762         pad = (u_char *) m_pad(m, padding + alen);
 763         if (pad == NULL) {
 764                 DPRINTF(("esp_output: m_pad failed for SA %s/%08lx\n",
 765                     ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
 766                 m = NULL;               /* NB: free'd by m_pad */
 767                 error = ENOBUFS;
 768                 goto bad;
 769         }
 770
 771         /*
 772          * Add padding: random, zero, or self-describing.
 773          * XXX catch unexpected setting
 774          */
 775         switch (sav->flags & SADB_X_EXT_PMASK) {
 776         case SADB_X_EXT_PRAND:
 777                 read_random(pad, padding - 2);
 778                 break;
 779         case SADB_X_EXT_PZERO:
 780                 bzero(pad, padding - 2);
 781                 break;
 782         case SADB_X_EXT_PSEQ:
 783                 for (i = 0; i < padding - 2; i++)
 784                         pad[i] = i+1;
 785                 break;
 786         }
 787
 788         /* Fix padding length and Next Protocol in padding itself. */
 789         pad[padding - 2] = padding - 2;
 790         m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1);
 791
 792         /* Fix Next Protocol in IPv4/IPv6 header. */
 793         prot = IPPROTO_ESP;
 794         m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot);
 795
 796         /* Get crypto descriptors. */
 797         crp = crypto_getreq(esph && espx ? 2 : 1);
 798         if (crp == NULL) {
 799                 DPRINTF(("esp_output: failed to acquire crypto descriptors\n"));
 800                 espstat.esps_crypto++;
 801                 error = ENOBUFS;
 802                 goto bad;
 803         }
 804
 805         if (espx) {
 806                 crde = crp->crp_desc;
 807                 crda = crde->crd_next;
 808
 809                 /* Encryption descriptor. */
 810                 crde->crd_skip = skip + hlen;
 811                 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
 812                 crde->crd_flags = CRD_F_ENCRYPT;
 813                 crde->crd_inject = skip + hlen - sav->ivlen;
 814
 815                 /* Encryption operation. */
 816                 crde->crd_alg = espx->type;
 817                 crde->crd_key = _KEYBUF(sav->key_enc);
 818                 crde->crd_klen = _KEYBITS(sav->key_enc);
 819                 /* XXX Rounds ? */
 820         } else
 821                 crda = crp->crp_desc;
 822
 823         /* IPsec-specific opaque crypto info. */
 824         tc = kmalloc(sizeof(struct tdb_crypto),
 825                         M_XDATA, M_INTWAIT | M_ZERO | M_NULLOK);
 826         if (tc == NULL) {
 827                 crypto_freereq(crp);
 828                 DPRINTF(("esp_output: failed to allocate tdb_crypto\n"));
 829                 espstat.esps_crypto++;
 830                 error = ENOBUFS;
 831                 goto bad;
 832         }
 833
 834         /* Callback parameters */
 835         tc->tc_isr = isr;
 836         tc->tc_spi = sav->spi;
 837         tc->tc_dst = saidx->dst;
 838         tc->tc_proto = saidx->proto;
 839
 840         /* Crypto operation descriptor. */
 841         crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
 842         crp->crp_flags = CRYPTO_F_IMBUF;
 843         crp->crp_buf = (caddr_t) m;
 844         crp->crp_callback = esp_output_cb;
 845         crp->crp_opaque = (caddr_t) tc;
 846         crp->crp_sid = sav->tdb_cryptoid;
 847
 848         if (esph) {
 849                 /* Authentication descriptor. */
 850                 crda->crd_skip = skip;
 851                 crda->crd_len = m->m_pkthdr.len - (skip + alen);
 852                 crda->crd_inject = m->m_pkthdr.len - alen;
 853
 854                 /* Authentication operation. */
 855                 crda->crd_alg = esph->type;
 856                 crda->crd_key = _KEYBUF(sav->key_auth);
 857                 crda->crd_klen = _KEYBITS(sav->key_auth);
 858         }
 859
 860         return crypto_dispatch(crp);
 861 bad:
 862         if (m)
 863                 m_freem(m);
 864         return (error);
 865 }
 866
 867 /*
 868  * ESP output callback from the crypto driver.
 869  */
 870 static int
 871 esp_output_cb(struct cryptop *crp)
 872 {
 873         struct tdb_crypto *tc;
 874         struct ipsecrequest *isr;
 875         struct secasvar *sav;
 876         struct mbuf *m;
 877         int err, error;
 878
 879         tc = (struct tdb_crypto *) crp->crp_opaque;
 880         KASSERT(tc != NULL, ("esp_output_cb: null opaque data area!"));
 881         m = (struct mbuf *) crp->crp_buf;
 882
 883         crit_enter();
 884
 885         isr = tc->tc_isr;
 886         sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi);
 887         if (sav == NULL) {
 888                 espstat.esps_notdb++;
 889                 DPRINTF(("esp_output_cb: SA expired while in crypto "
 890                     "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst),
 891                     (u_long) ntohl(tc->tc_spi), tc->tc_proto));
 892                 error = ENOBUFS;                /*XXX*/
 893                 goto bad;
 894         }
 895         KASSERT(isr->sav == sav,
 896                 ("esp_output_cb: SA changed was %p now %p\n", isr->sav, sav));
 897
 898         /* Check for crypto errors. */
 899         if (crp->crp_etype) {
 900                 /* Reset session ID. */
 901                 if (sav->tdb_cryptoid != 0)
 902                         sav->tdb_cryptoid = crp->crp_sid;
 903
 904                 if (crp->crp_etype == EAGAIN) {
 905                         KEY_FREESAV(&sav);
 906                         crit_exit();
 907                         return crypto_dispatch(crp);
 908                 }
 909
 910                 espstat.esps_noxform++;
 911                 DPRINTF(("esp_output_cb: crypto error %d\n", crp->crp_etype));
 912                 error = crp->crp_etype;
 913                 goto bad;
 914         }
 915
 916         /* Shouldn't happen... */
 917         if (m == NULL) {
 918                 espstat.esps_crypto++;
 919                 DPRINTF(("esp_output_cb: bogus returned buffer from crypto\n"));
 920                 error = EINVAL;
 921                 goto bad;
 922         }
 923         espstat.esps_hist[sav->alg_enc]++;
 924         if (sav->tdb_authalgxform != NULL)
 925                 ahstat.ahs_hist[sav->alg_auth]++;
 926
 927         /* Release crypto descriptors. */
 928         kfree(tc, M_XDATA);
 929         crypto_freereq(crp);
 930
 931         /* NB: m is reclaimed by ipsec_process_done. */
 932         err = ipsec_process_done(m, isr);
 933         KEY_FREESAV(&sav);
 934         crit_exit();
 935         return err;
 936 bad:
 937         if (sav)
 938                 KEY_FREESAV(&sav);
 939         crit_exit();
 940         if (m)
 941                 m_freem(m);
 942         kfree(tc, M_XDATA);
 943         crypto_freereq(crp);
 944         return error;
 945 }
 946
 947 static struct xformsw esp_xformsw = {
 948         XF_ESP,         XFT_CONF|XFT_AUTH,      "IPsec ESP",
 949         esp_init,       esp_zeroize,            esp_input,
 950         esp_output
 951 };
 952
 953 static void
 954 esp_attach(void)
 955 {
 956 #define MAXIV(xform)                                    \
 957         if (xform.blocksize > esp_max_ivlen)            \
 958                 esp_max_ivlen = xform.blocksize         \
 959
 960         esp_max_ivlen = 0;
 961         MAXIV(enc_xform_des);           /* SADB_EALG_DESCBC */
 962         MAXIV(enc_xform_3des);          /* SADB_EALG_3DESCBC */
 963         MAXIV(enc_xform_rijndael128);   /* SADB_X_EALG_AES */
 964         MAXIV(enc_xform_blf);           /* SADB_X_EALG_BLOWFISHCBC */
 965         MAXIV(enc_xform_cast5);         /* SADB_X_EALG_CAST128CBC */
 966         MAXIV(enc_xform_skipjack);      /* SADB_X_EALG_SKIPJACK */
 967         MAXIV(enc_xform_null);          /* SADB_EALG_NULL */
 968
 969         xform_register(&esp_xformsw);
 970 #undef MAXIV
 971 }
 972 SYSINIT(esp_xform_init, SI_SUB_DRIVERS, SI_ORDER_FIRST, esp_attach, NULL)