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 1.12 2006/10/12 01:32:51 hsu 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         if (sav->iv == NULL) {
 196                 DPRINTF(("esp_init: no memory for IV\n"));
 197                 return EINVAL;
 198         }
 199         key_randomfill(sav->iv, sav->ivlen);    /*XXX*/
 200
 201         /*
 202          * Setup AH-related state.
 203          */
 204         if (sav->alg_auth != 0) {
 205                 error = ah_init0(sav, xsp, &cria);
 206                 if (error)
 207                         return error;
 208         }
 209
 210         /* NB: override anything set in ah_init0 */
 211         sav->tdb_xform = xsp;
 212         sav->tdb_encalgxform = txform;
 213
 214         /* Initialize crypto session. */
 215         bzero(&crie, sizeof (crie));
 216         crie.cri_alg = sav->tdb_encalgxform->type;
 217         crie.cri_klen = _KEYBITS(sav->key_enc);
 218         crie.cri_key = _KEYBUF(sav->key_enc);
 219         /* XXX Rounds ? */
 220
 221         if (sav->tdb_authalgxform && sav->tdb_encalgxform) {
 222                 /* init both auth & enc */
 223                 crie.cri_next = &cria;
 224                 error = crypto_newsession(&sav->tdb_cryptoid,
 225                                           &crie, crypto_support);
 226         } else if (sav->tdb_encalgxform) {
 227                 error = crypto_newsession(&sav->tdb_cryptoid,
 228                                           &crie, crypto_support);
 229         } else if (sav->tdb_authalgxform) {
 230                 error = crypto_newsession(&sav->tdb_cryptoid,
 231                                           &cria, crypto_support);
 232         } else {
 233                 /* XXX cannot happen? */
 234                 DPRINTF(("esp_init: no encoding OR authentication xform!\n"));
 235                 error = EINVAL;
 236         }
 237         return error;
 238 }
 239
 240 /*
 241  * Paranoia.
 242  */
 243 static int
 244 esp_zeroize(struct secasvar *sav)
 245 {
 246         /* NB: ah_zerorize free's the crypto session state */
 247         int error = ah_zeroize(sav);
 248
 249         if (sav->key_enc)
 250                 bzero(_KEYBUF(sav->key_enc), _KEYLEN(sav->key_enc));
 251         /* NB: sav->iv is freed elsewhere, even though we malloc it! */
 252         sav->tdb_encalgxform = NULL;
 253         sav->tdb_xform = NULL;
 254         return error;
 255 }
 256
 257 /*
 258  * ESP input processing, called (eventually) through the protocol switch.
 259  */
 260 static int
 261 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
 262 {
 263         struct auth_hash *esph;
 264         struct enc_xform *espx;
 265         struct tdb_ident *tdbi;
 266         struct tdb_crypto *tc;
 267         int plen, alen, hlen;
 268         struct m_tag *mtag;
 269         struct newesp *esp;
 270
 271         struct cryptodesc *crde;
 272         struct cryptop *crp;
 273
 274         KASSERT(sav != NULL, ("esp_input: null SA"));
 275         KASSERT(sav->tdb_encalgxform != NULL,
 276                 ("esp_input: null encoding xform"));
 277         KASSERT((skip&3) == 0 && (m->m_pkthdr.len&3) == 0,
 278                 ("esp_input: misaligned packet, skip %u pkt len %u",
 279                         skip, m->m_pkthdr.len));
 280
 281         /* XXX don't pullup, just copy header */
 282         IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp));
 283
 284         esph = sav->tdb_authalgxform;
 285         espx = sav->tdb_encalgxform;
 286
 287         /* Determine the ESP header length */
 288         if (sav->flags & SADB_X_EXT_OLD)
 289                 hlen = sizeof (struct esp) + sav->ivlen;
 290         else
 291                 hlen = sizeof (struct newesp) + sav->ivlen;
 292         /* Authenticator hash size */
 293         alen = esph ? AH_HMAC_HASHLEN : 0;
 294
 295         /*
 296          * Verify payload length is multiple of encryption algorithm
 297          * block size.
 298          *
 299          * NB: This works for the null algorithm because the blocksize
 300          *     is 4 and all packets must be 4-byte aligned regardless
 301          *     of the algorithm.
 302          */
 303         plen = m->m_pkthdr.len - (skip + hlen + alen);
 304         if ((plen & (espx->blocksize - 1)) || (plen <= 0)) {
 305                 DPRINTF(("esp_input: "
 306                     "payload of %d octets not a multiple of %d octets,"
 307                     "  SA %s/%08lx\n",
 308                     plen, espx->blocksize,
 309                     ipsec_address(&sav->sah->saidx.dst),
 310                     (u_long) ntohl(sav->spi)));
 311                 espstat.esps_badilen++;
 312                 m_freem(m);
 313                 return EINVAL;
 314         }
 315
 316         /*
 317          * Check sequence number.
 318          */
 319         if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) {
 320                 DPRINTF(("esp_input: packet replay check for %s\n",
 321                     ipsec_logsastr(sav)));      /*XXX*/
 322                 espstat.esps_replay++;
 323                 m_freem(m);
 324                 return ENOBUFS;         /*XXX*/
 325         }
 326
 327         /* Update the counters */
 328         espstat.esps_ibytes += m->m_pkthdr.len - skip - hlen - alen;
 329
 330         /* Find out if we've already done crypto */
 331         for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL);
 332              mtag != NULL;
 333              mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) {
 334                 tdbi = (struct tdb_ident *)m_tag_data(mtag);
 335                 if (tdbi->proto == sav->sah->saidx.proto &&
 336                     tdbi->spi == sav->spi &&
 337                     !bcmp(&tdbi->dst, &sav->sah->saidx.dst,
 338                           sizeof(union sockaddr_union)))
 339                         break;
 340         }
 341
 342         /* Get crypto descriptors */
 343         crp = crypto_getreq(esph && espx ? 2 : 1);
 344         if (crp == NULL) {
 345                 DPRINTF(("esp_input: failed to acquire crypto descriptors\n"));
 346                 espstat.esps_crypto++;
 347                 m_freem(m);
 348                 return ENOBUFS;
 349         }
 350
 351         /* Get IPsec-specific opaque pointer */
 352         if (esph == NULL || mtag != NULL)
 353                 tc = kmalloc(sizeof(struct tdb_crypto),
 354                             M_XDATA, M_INTWAIT | M_ZERO | M_NULLOK);
 355         else
 356                 tc = kmalloc(sizeof(struct tdb_crypto) + alen,
 357                             M_XDATA, M_INTWAIT | M_ZERO | M_NULLOK);
 358         if (tc == NULL) {
 359                 crypto_freereq(crp);
 360                 DPRINTF(("esp_input: failed to allocate tdb_crypto\n"));
 361                 espstat.esps_crypto++;
 362                 m_freem(m);
 363                 return ENOBUFS;
 364         }
 365
 366         tc->tc_ptr = (caddr_t) mtag;
 367
 368         if (esph) {
 369                 struct cryptodesc *crda = crp->crp_desc;
 370
 371                 KASSERT(crda != NULL, ("esp_input: null ah crypto descriptor"));
 372
 373                 /* Authentication descriptor */
 374                 crda->crd_skip = skip;
 375                 crda->crd_len = m->m_pkthdr.len - (skip + alen);
 376                 crda->crd_inject = m->m_pkthdr.len - alen;
 377
 378                 crda->crd_alg = esph->type;
 379                 crda->crd_key = _KEYBUF(sav->key_auth);
 380                 crda->crd_klen = _KEYBITS(sav->key_auth);
 381
 382                 /* Copy the authenticator */
 383                 if (mtag == NULL)
 384                         m_copydata(m, m->m_pkthdr.len - alen, alen,
 385                                    (caddr_t) (tc + 1));
 386
 387                 /* Chain authentication request */
 388                 crde = crda->crd_next;
 389         } else {
 390                 crde = crp->crp_desc;
 391         }
 392
 393         /* Crypto operation descriptor */
 394         crp->crp_ilen = m->m_pkthdr.len; /* Total input length */
 395         crp->crp_flags = CRYPTO_F_IMBUF;
 396         crp->crp_buf = (caddr_t) m;
 397         crp->crp_callback = esp_input_cb;
 398         crp->crp_sid = sav->tdb_cryptoid;
 399         crp->crp_opaque = (caddr_t) tc;
 400
 401         /* These are passed as-is to the callback */
 402         tc->tc_spi = sav->spi;
 403         tc->tc_dst = sav->sah->saidx.dst;
 404         tc->tc_proto = sav->sah->saidx.proto;
 405         tc->tc_protoff = protoff;
 406         tc->tc_skip = skip;
 407
 408         /* Decryption descriptor */
 409         if (espx) {
 410                 KASSERT(crde != NULL, ("esp_input: null esp crypto descriptor"));
 411                 crde->crd_skip = skip + hlen;
 412                 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
 413                 crde->crd_inject = skip + hlen - sav->ivlen;
 414
 415                 crde->crd_alg = espx->type;
 416                 crde->crd_key = _KEYBUF(sav->key_enc);
 417                 crde->crd_klen = _KEYBITS(sav->key_enc);
 418                 /* XXX Rounds ? */
 419         }
 420
 421         if (mtag == NULL)
 422                 return crypto_dispatch(crp);
 423         else
 424                 return esp_input_cb(crp);
 425 }
 426
 427 #ifdef INET6
 428 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do {              \
 429         if (saidx->dst.sa.sa_family == AF_INET6) {                           \
 430                 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \
 431         } else {                                                             \
 432                 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \
 433         }                                                                    \
 434 } while (0)
 435 #else
 436 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag)                   \
 437         (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag))
 438 #endif
 439
 440 /*
 441  * ESP input callback from the crypto driver.
 442  */
 443 static int
 444 esp_input_cb(struct cryptop *crp)
 445 {
 446         u_int8_t lastthree[3], aalg[AH_HMAC_HASHLEN];
 447         int hlen, skip, protoff, error;
 448         struct mbuf *m;
 449         struct cryptodesc *crd;
 450         struct auth_hash *esph;
 451         struct enc_xform *espx;
 452         struct tdb_crypto *tc;
 453         struct m_tag *mtag;
 454         struct secasvar *sav;
 455         struct secasindex *saidx;
 456         caddr_t ptr;
 457
 458         crd = crp->crp_desc;
 459         KASSERT(crd != NULL, ("esp_input_cb: null crypto descriptor!"));
 460
 461         tc = (struct tdb_crypto *) crp->crp_opaque;
 462         KASSERT(tc != NULL, ("esp_input_cb: null opaque crypto data area!"));
 463         skip = tc->tc_skip;
 464         protoff = tc->tc_protoff;
 465         mtag = (struct m_tag *) tc->tc_ptr;
 466         m = (struct mbuf *) crp->crp_buf;
 467
 468         crit_enter();
 469
 470         sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi);
 471         if (sav == NULL) {
 472                 espstat.esps_notdb++;
 473                 DPRINTF(("esp_input_cb: SA expired while in crypto "
 474                     "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst),
 475                     (u_long) ntohl(tc->tc_spi), tc->tc_proto));
 476                 error = ENOBUFS;                /*XXX*/
 477                 goto bad;
 478         }
 479
 480         saidx = &sav->sah->saidx;
 481         KASSERT(saidx->dst.sa.sa_family == AF_INET ||
 482                 saidx->dst.sa.sa_family == AF_INET6,
 483                 ("ah_input_cb: unexpected protocol family %u",
 484                  saidx->dst.sa.sa_family));
 485
 486         esph = sav->tdb_authalgxform;
 487         espx = sav->tdb_encalgxform;
 488
 489         /* Check for crypto errors */
 490         if (crp->crp_etype) {
 491                 /* Reset the session ID */
 492                 if (sav->tdb_cryptoid != 0)
 493                         sav->tdb_cryptoid = crp->crp_sid;
 494
 495                 if (crp->crp_etype == EAGAIN) {
 496                         KEY_FREESAV(&sav);
 497                         crit_exit();
 498                         return crypto_dispatch(crp);
 499                 }
 500
 501                 espstat.esps_noxform++;
 502                 DPRINTF(("esp_input_cb: crypto error %d\n", crp->crp_etype));
 503                 error = crp->crp_etype;
 504                 goto bad;
 505         }
 506
 507         /* Shouldn't happen... */
 508         if (m == NULL) {
 509                 espstat.esps_crypto++;
 510                 DPRINTF(("esp_input_cb: bogus returned buffer from crypto\n"));
 511                 error = EINVAL;
 512                 goto bad;
 513         }
 514         espstat.esps_hist[sav->alg_enc]++;
 515
 516         /* If authentication was performed, check now. */
 517         if (esph != NULL) {
 518                 /*
 519                  * If we have a tag, it means an IPsec-aware NIC did
 520                  * the verification for us.  Otherwise we need to
 521                  * check the authentication calculation.
 522                  */
 523                 ahstat.ahs_hist[sav->alg_auth]++;
 524                 if (mtag == NULL) {
 525                         /* Copy the authenticator from the packet */
 526                         m_copydata(m, m->m_pkthdr.len - esph->authsize,
 527                                 esph->authsize, aalg);
 528
 529                         ptr = (caddr_t) (tc + 1);
 530
 531                         /* Verify authenticator */
 532                         if (bcmp(ptr, aalg, esph->authsize) != 0) {
 533                                 DPRINTF(("esp_input_cb: "
 534                     "authentication hash mismatch for packet in SA %s/%08lx\n",
 535                                     ipsec_address(&saidx->dst),
 536                                     (u_long) ntohl(sav->spi)));
 537                                 espstat.esps_badauth++;
 538                                 error = EACCES;
 539                                 goto bad;
 540                         }
 541                 }
 542
 543                 /* Remove trailing authenticator */
 544                 m_adj(m, -(esph->authsize));
 545         }
 546
 547         /* Release the crypto descriptors */
 548         kfree(tc, M_XDATA), tc = NULL;
 549         crypto_freereq(crp), crp = NULL;
 550
 551         /*
 552          * Packet is now decrypted.
 553          */
 554         m->m_flags |= M_DECRYPTED;
 555
 556         /*
 557          * Update replay sequence number, if appropriate.
 558          */
 559         if (sav->replay) {
 560                 u_int32_t seq;
 561
 562                 m_copydata(m, skip + offsetof(struct newesp, esp_seq),
 563                            sizeof (seq), (caddr_t) &seq);
 564                 if (ipsec_updatereplay(ntohl(seq), sav)) {
 565                         DPRINTF(("%s: packet replay check for %s\n", __func__,
 566                             ipsec_logsastr(sav)));
 567                         espstat.esps_replay++;
 568                         error = ENOBUFS;
 569                         goto bad;
 570                 }
 571         }
 572
 573         /* Determine the ESP header length */
 574         if (sav->flags & SADB_X_EXT_OLD)
 575                 hlen = sizeof (struct esp) + sav->ivlen;
 576         else
 577                 hlen = sizeof (struct newesp) + sav->ivlen;
 578
 579         /* Remove the ESP header and IV from the mbuf. */
 580         error = m_striphdr(m, skip, hlen);
 581         if (error) {
 582                 espstat.esps_hdrops++;
 583                 DPRINTF(("esp_input_cb: bad mbuf chain, SA %s/%08lx\n",
 584                     ipsec_address(&sav->sah->saidx.dst),
 585                     (u_long) ntohl(sav->spi)));
 586                 goto bad;
 587         }
 588
 589         /* Save the last three bytes of decrypted data */
 590         m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree);
 591
 592         /* Verify pad length */
 593         if (lastthree[1] + 2 > m->m_pkthdr.len - skip) {
 594                 espstat.esps_badilen++;
 595                 DPRINTF(("esp_input_cb: invalid padding length %d "
 596                          "for %u byte packet in SA %s/%08lx\n",
 597                          lastthree[1], m->m_pkthdr.len - skip,
 598                          ipsec_address(&sav->sah->saidx.dst),
 599                          (u_long) ntohl(sav->spi)));
 600                 error = EINVAL;
 601                 goto bad;
 602         }
 603
 604         /* Verify correct decryption by checking the last padding bytes */
 605         if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) {
 606                 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) {
 607                         espstat.esps_badenc++;
 608                         DPRINTF(("esp_input_cb: decryption failed "
 609                                 "for packet in SA %s/%08lx\n",
 610                                 ipsec_address(&sav->sah->saidx.dst),
 611                                 (u_long) ntohl(sav->spi)));
 612 DPRINTF(("esp_input_cb: %x %x\n", lastthree[0], lastthree[1]));
 613                         error = EINVAL;
 614                         goto bad;
 615                 }
 616         }
 617
 618         /* Trim the mbuf chain to remove trailing authenticator and padding */
 619         m_adj(m, -(lastthree[1] + 2));
 620
 621         /* Restore the Next Protocol field */
 622         m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2);
 623
 624         IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag);
 625
 626         KEY_FREESAV(&sav);
 627         crit_exit();
 628         return error;
 629 bad:
 630         if (sav)
 631                 KEY_FREESAV(&sav);
 632         crit_exit();
 633         if (m != NULL)
 634                 m_freem(m);
 635         if (tc != NULL)
 636                 kfree(tc, M_XDATA);
 637         if (crp != NULL)
 638                 crypto_freereq(crp);
 639         return error;
 640 }
 641
 642 /*
 643  * ESP output routine, called by ipsec[46]_process_packet().
 644  */
 645 static int
 646 esp_output(
 647         struct mbuf *m,
 648         struct ipsecrequest *isr,
 649         struct mbuf **mp,
 650         int skip,
 651         int protoff
 652 )
 653 {
 654         struct enc_xform *espx;
 655         struct auth_hash *esph;
 656         int hlen, rlen, plen, padding, blks, alen, i, roff;
 657         struct mbuf *mo = (struct mbuf *) NULL;
 658         struct tdb_crypto *tc;
 659         struct secasvar *sav;
 660         struct secasindex *saidx;
 661         unsigned char *pad;
 662         u_int8_t prot;
 663         int error, maxpacketsize;
 664
 665         struct cryptodesc *crde = NULL, *crda = NULL;
 666         struct cryptop *crp;
 667
 668         sav = isr->sav;
 669         KASSERT(sav != NULL, ("esp_output: null SA"));
 670         esph = sav->tdb_authalgxform;
 671         espx = sav->tdb_encalgxform;
 672         KASSERT(espx != NULL, ("esp_output: null encoding xform"));
 673
 674         if (sav->flags & SADB_X_EXT_OLD)
 675                 hlen = sizeof (struct esp) + sav->ivlen;
 676         else
 677                 hlen = sizeof (struct newesp) + sav->ivlen;
 678
 679         rlen = m->m_pkthdr.len - skip;  /* Raw payload length. */
 680         /*
 681          * NB: The null encoding transform has a blocksize of 4
 682          *     so that headers are properly aligned.
 683          */
 684         blks = espx->blocksize;         /* IV blocksize */
 685
 686         /* XXX clamp padding length a la KAME??? */
 687         padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;
 688         plen = rlen + padding;          /* Padded payload length. */
 689
 690         if (esph)
 691                 alen = AH_HMAC_HASHLEN;
 692         else
 693                 alen = 0;
 694
 695         espstat.esps_output++;
 696
 697         saidx = &sav->sah->saidx;
 698         /* Check for maximum packet size violations. */
 699         switch (saidx->dst.sa.sa_family) {
 700 #ifdef INET
 701         case AF_INET:
 702                 maxpacketsize = IP_MAXPACKET;
 703                 break;
 704 #endif /* INET */
 705 #ifdef INET6
 706         case AF_INET6:
 707                 maxpacketsize = IPV6_MAXPACKET;
 708                 break;
 709 #endif /* INET6 */
 710         default:
 711                 DPRINTF(("esp_output: unknown/unsupported protocol "
 712                     "family %d, SA %s/%08lx\n",
 713                     saidx->dst.sa.sa_family, ipsec_address(&saidx->dst),
 714                     (u_long) ntohl(sav->spi)));
 715                 espstat.esps_nopf++;
 716                 error = EPFNOSUPPORT;
 717                 goto bad;
 718         }
 719         if (skip + hlen + rlen + padding + alen > maxpacketsize) {
 720                 DPRINTF(("esp_output: packet in SA %s/%08lx got too big "
 721                     "(len %u, max len %u)\n",
 722                     ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi),
 723                     skip + hlen + rlen + padding + alen, maxpacketsize));
 724                 espstat.esps_toobig++;
 725                 error = EMSGSIZE;
 726                 goto bad;
 727         }
 728
 729         /* Update the counters. */
 730         espstat.esps_obytes += m->m_pkthdr.len - skip;
 731
 732         m = m_clone(m);
 733         if (m == NULL) {
 734                 DPRINTF(("esp_output: cannot clone mbuf chain, SA %s/%08lx\n",
 735                     ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
 736                 espstat.esps_hdrops++;
 737                 error = ENOBUFS;
 738                 goto bad;
 739         }
 740
 741         /* Inject ESP header. */
 742         mo = m_makespace(m, skip, hlen, &roff);
 743         if (mo == NULL) {
 744                 DPRINTF(("esp_output: failed to inject %u byte ESP hdr for SA "
 745                     "%s/%08lx\n",
 746                     hlen, ipsec_address(&saidx->dst),
 747                     (u_long) ntohl(sav->spi)));
 748                 espstat.esps_hdrops++;          /* XXX diffs from openbsd */
 749                 error = ENOBUFS;
 750                 goto bad;
 751         }
 752
 753         /* Initialize ESP header. */
 754         bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t));
 755         if (sav->replay) {
 756                 u_int32_t replay = htonl(++(sav->replay->count));
 757                 bcopy((caddr_t) &replay,
 758                     mtod(mo, caddr_t) + roff + sizeof(u_int32_t),
 759                     sizeof(u_int32_t));
 760         }
 761
 762         /*
 763          * Add padding -- better to do it ourselves than use the crypto engine,
 764          * although if/when we support compression, we'd have to do that.
 765          */
 766         pad = (u_char *) m_pad(m, padding + alen);
 767         if (pad == NULL) {
 768                 DPRINTF(("esp_output: m_pad failed for SA %s/%08lx\n",
 769                     ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
 770                 m = NULL;               /* NB: free'd by m_pad */
 771                 error = ENOBUFS;
 772                 goto bad;
 773         }
 774
 775         /*
 776          * Add padding: random, zero, or self-describing.
 777          * XXX catch unexpected setting
 778          */
 779         switch (sav->flags & SADB_X_EXT_PMASK) {
 780         case SADB_X_EXT_PRAND:
 781                 read_random(pad, padding - 2);
 782                 break;
 783         case SADB_X_EXT_PZERO:
 784                 bzero(pad, padding - 2);
 785                 break;
 786         case SADB_X_EXT_PSEQ:
 787                 for (i = 0; i < padding - 2; i++)
 788                         pad[i] = i+1;
 789                 break;
 790         }
 791
 792         /* Fix padding length and Next Protocol in padding itself. */
 793         pad[padding - 2] = padding - 2;
 794         m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1);
 795
 796         /* Fix Next Protocol in IPv4/IPv6 header. */
 797         prot = IPPROTO_ESP;
 798         m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot);
 799
 800         /* Get crypto descriptors. */
 801         crp = crypto_getreq(esph && espx ? 2 : 1);
 802         if (crp == NULL) {
 803                 DPRINTF(("esp_output: failed to acquire crypto descriptors\n"));
 804                 espstat.esps_crypto++;
 805                 error = ENOBUFS;
 806                 goto bad;
 807         }
 808
 809         if (espx) {
 810                 crde = crp->crp_desc;
 811                 crda = crde->crd_next;
 812
 813                 /* Encryption descriptor. */
 814                 crde->crd_skip = skip + hlen;
 815                 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
 816                 crde->crd_flags = CRD_F_ENCRYPT;
 817                 crde->crd_inject = skip + hlen - sav->ivlen;
 818
 819                 /* Encryption operation. */
 820                 crde->crd_alg = espx->type;
 821                 crde->crd_key = _KEYBUF(sav->key_enc);
 822                 crde->crd_klen = _KEYBITS(sav->key_enc);
 823                 /* XXX Rounds ? */
 824         } else
 825                 crda = crp->crp_desc;
 826
 827         /* IPsec-specific opaque crypto info. */
 828         tc = kmalloc(sizeof(struct tdb_crypto),
 829                         M_XDATA, M_INTWAIT | M_ZERO | M_NULLOK);
 830         if (tc == NULL) {
 831                 crypto_freereq(crp);
 832                 DPRINTF(("esp_output: failed to allocate tdb_crypto\n"));
 833                 espstat.esps_crypto++;
 834                 error = ENOBUFS;
 835                 goto bad;
 836         }
 837
 838         /* Callback parameters */
 839         tc->tc_isr = isr;
 840         tc->tc_spi = sav->spi;
 841         tc->tc_dst = saidx->dst;
 842         tc->tc_proto = saidx->proto;
 843
 844         /* Crypto operation descriptor. */
 845         crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
 846         crp->crp_flags = CRYPTO_F_IMBUF;
 847         crp->crp_buf = (caddr_t) m;
 848         crp->crp_callback = esp_output_cb;
 849         crp->crp_opaque = (caddr_t) tc;
 850         crp->crp_sid = sav->tdb_cryptoid;
 851
 852         if (esph) {
 853                 /* Authentication descriptor. */
 854                 crda->crd_skip = skip;
 855                 crda->crd_len = m->m_pkthdr.len - (skip + alen);
 856                 crda->crd_inject = m->m_pkthdr.len - alen;
 857
 858                 /* Authentication operation. */
 859                 crda->crd_alg = esph->type;
 860                 crda->crd_key = _KEYBUF(sav->key_auth);
 861                 crda->crd_klen = _KEYBITS(sav->key_auth);
 862         }
 863
 864         return crypto_dispatch(crp);
 865 bad:
 866         if (m)
 867                 m_freem(m);
 868         return (error);
 869 }
 870
 871 /*
 872  * ESP output callback from the crypto driver.
 873  */
 874 static int
 875 esp_output_cb(struct cryptop *crp)
 876 {
 877         struct tdb_crypto *tc;
 878         struct ipsecrequest *isr;
 879         struct secasvar *sav;
 880         struct mbuf *m;
 881         int err, error;
 882
 883         tc = (struct tdb_crypto *) crp->crp_opaque;
 884         KASSERT(tc != NULL, ("esp_output_cb: null opaque data area!"));
 885         m = (struct mbuf *) crp->crp_buf;
 886
 887         crit_enter();
 888
 889         isr = tc->tc_isr;
 890         sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi);
 891         if (sav == NULL) {
 892                 espstat.esps_notdb++;
 893                 DPRINTF(("esp_output_cb: SA expired while in crypto "
 894                     "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst),
 895                     (u_long) ntohl(tc->tc_spi), tc->tc_proto));
 896                 error = ENOBUFS;                /*XXX*/
 897                 goto bad;
 898         }
 899         KASSERT(isr->sav == sav,
 900                 ("esp_output_cb: SA changed was %p now %p\n", isr->sav, sav));
 901
 902         /* Check for crypto errors. */
 903         if (crp->crp_etype) {
 904                 /* Reset session ID. */
 905                 if (sav->tdb_cryptoid != 0)
 906                         sav->tdb_cryptoid = crp->crp_sid;
 907
 908                 if (crp->crp_etype == EAGAIN) {
 909                         KEY_FREESAV(&sav);
 910                         crit_exit();
 911                         return crypto_dispatch(crp);
 912                 }
 913
 914                 espstat.esps_noxform++;
 915                 DPRINTF(("esp_output_cb: crypto error %d\n", crp->crp_etype));
 916                 error = crp->crp_etype;
 917                 goto bad;
 918         }
 919
 920         /* Shouldn't happen... */
 921         if (m == NULL) {
 922                 espstat.esps_crypto++;
 923                 DPRINTF(("esp_output_cb: bogus returned buffer from crypto\n"));
 924                 error = EINVAL;
 925                 goto bad;
 926         }
 927         espstat.esps_hist[sav->alg_enc]++;
 928         if (sav->tdb_authalgxform != NULL)
 929                 ahstat.ahs_hist[sav->alg_auth]++;
 930
 931         /* Release crypto descriptors. */
 932         kfree(tc, M_XDATA);
 933         crypto_freereq(crp);
 934
 935         /* NB: m is reclaimed by ipsec_process_done. */
 936         err = ipsec_process_done(m, isr);
 937         KEY_FREESAV(&sav);
 938         crit_exit();
 939         return err;
 940 bad:
 941         if (sav)
 942                 KEY_FREESAV(&sav);
 943         crit_exit();
 944         if (m)
 945                 m_freem(m);
 946         kfree(tc, M_XDATA);
 947         crypto_freereq(crp);
 948         return error;
 949 }
 950
 951 static struct xformsw esp_xformsw = {
 952         XF_ESP,         XFT_CONF|XFT_AUTH,      "IPsec ESP",
 953         esp_init,       esp_zeroize,            esp_input,
 954         esp_output
 955 };
 956
 957 static void
 958 esp_attach(void)
 959 {
 960 #define MAXIV(xform)                                    \
 961         if (xform.blocksize > esp_max_ivlen)            \
 962                 esp_max_ivlen = xform.blocksize         \
 963
 964         esp_max_ivlen = 0;
 965         MAXIV(enc_xform_des);           /* SADB_EALG_DESCBC */
 966         MAXIV(enc_xform_3des);          /* SADB_EALG_3DESCBC */
 967         MAXIV(enc_xform_rijndael128);   /* SADB_X_EALG_AES */
 968         MAXIV(enc_xform_blf);           /* SADB_X_EALG_BLOWFISHCBC */
 969         MAXIV(enc_xform_cast5);         /* SADB_X_EALG_CAST128CBC */
 970         MAXIV(enc_xform_skipjack);      /* SADB_X_EALG_SKIPJACK */
 971         MAXIV(enc_xform_null);          /* SADB_EALG_NULL */
 972
 973         xform_register(&esp_xformsw);
 974 #undef MAXIV
 975 }
 976 SYSINIT(esp_xform_init, SI_SUB_DRIVERS, SI_ORDER_FIRST, esp_attach, NULL)