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