1 /* $NetBSD: xform_esp.c,v 1.17 2008/02/04 00:35:35 tls Exp $ */ 2 /* $FreeBSD: src/sys/netipsec/xform_esp.c,v 1.2.2.1 2003/01/24 05:11:36 sam Exp $ */ 3 /* $OpenBSD: ip_esp.c,v 1.69 2001/06/26 06:18:59 angelos Exp $ */ 4 5 /* 6 * The authors of this code are John Ioannidis (ji@tla.org), 7 * Angelos D. Keromytis (kermit@csd.uch.gr) and 8 * Niels Provos (provos@physnet.uni-hamburg.de). 9 * 10 * The original version of this code was written by John Ioannidis 11 * for BSD/OS in Athens, Greece, in November 1995. 12 * 13 * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996, 14 * by Angelos D. Keromytis. 15 * 16 * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis 17 * and Niels Provos. 18 * 19 * Additional features in 1999 by Angelos D. Keromytis. 20 * 21 * Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis, 22 * Angelos D. Keromytis and Niels Provos. 23 * Copyright (c) 2001 Angelos D. Keromytis. 24 * 25 * Permission to use, copy, and modify this software with or without fee 26 * is hereby granted, provided that this entire notice is included in 27 * all copies of any software which is or includes a copy or 28 * modification of this software. 29 * You may use this code under the GNU public license if you so wish. Please 30 * contribute changes back to the authors under this freer than GPL license 31 * so that we may further the use of strong encryption without limitations to 32 * all. 33 * 34 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR 35 * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY 36 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE 37 * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR 38 * PURPOSE. 39 */ 40 41 #include <sys/cdefs.h> 42 __KERNEL_RCSID(0, "$NetBSD: xform_esp.c,v 1.17 2008/02/04 00:35:35 tls Exp $"); 43 44 #include "opt_inet.h" 45 #ifdef __FreeBSD__ 46 #include "opt_inet6.h" 47 #endif 48 49 #include <sys/param.h> 50 #include <sys/systm.h> 51 #include <sys/mbuf.h> 52 #include <sys/socket.h> 53 #include <sys/syslog.h> 54 #include <sys/kernel.h> 55 /*#include <sys/random.h>*/ 56 #include <sys/sysctl.h> 57 58 #include <net/if.h> 59 60 #include <netinet/in.h> 61 #include <netinet/in_systm.h> 62 #include <netinet/ip.h> 63 #include <netinet/ip_ecn.h> 64 #include <netinet/ip6.h> 65 66 #include <net/route.h> 67 #include <netipsec/ipsec.h> 68 #include <netipsec/ah.h> 69 #include <netipsec/ah_var.h> 70 #include <netipsec/esp.h> 71 #include <netipsec/esp_var.h> 72 #include <netipsec/xform.h> 73 74 #ifdef INET6 75 #include <netinet6/ip6_var.h> 76 #include <netipsec/ipsec6.h> 77 # ifdef __FreeBSD__ 78 # include <netinet6/ip6_ecn.h> 79 # endif 80 #endif 81 82 #include <netipsec/key.h> 83 #include <netipsec/key_debug.h> 84 85 #include <netipsec/ipsec_osdep.h> 86 87 #include <opencrypto/cryptodev.h> 88 #include <opencrypto/xform.h> 89 90 int esp_enable = 1; 91 struct espstat espstat; 92 93 #ifdef __FreeBSD__ 94 SYSCTL_DECL(_net_inet_esp); 95 SYSCTL_INT(_net_inet_esp, OID_AUTO, 96 esp_enable, CTLFLAG_RW, &esp_enable, 0, ""); 97 SYSCTL_STRUCT(_net_inet_esp, IPSECCTL_STATS, 98 stats, CTLFLAG_RD, &espstat, espstat, ""); 99 #endif /* __FreeBSD__ */ 100 101 static int esp_max_ivlen; /* max iv length over all algorithms */ 102 103 static int esp_input_cb(struct cryptop *op); 104 static int esp_output_cb(struct cryptop *crp); 105 106 /* 107 * NB: this is public for use by the PF_KEY support. 108 * NB: if you add support here; be sure to add code to esp_attach below! 109 */ 110 struct enc_xform * 111 esp_algorithm_lookup(int alg) 112 { 113 if (alg >= ESP_ALG_MAX) 114 return NULL; 115 switch (alg) { 116 case SADB_EALG_DESCBC: 117 return &enc_xform_des; 118 case SADB_EALG_3DESCBC: 119 return &enc_xform_3des; 120 case SADB_X_EALG_AES: 121 return &enc_xform_rijndael128; 122 case SADB_X_EALG_BLOWFISHCBC: 123 return &enc_xform_blf; 124 case SADB_X_EALG_CAST128CBC: 125 return &enc_xform_cast5; 126 case SADB_X_EALG_SKIPJACK: 127 return &enc_xform_skipjack; 128 case SADB_EALG_NULL: 129 return &enc_xform_null; 130 } 131 return NULL; 132 } 133 134 size_t 135 esp_hdrsiz(struct secasvar *sav) 136 { 137 size_t size; 138 139 if (sav != NULL) { 140 /*XXX not right for null algorithm--does it matter??*/ 141 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 142 ("esp_hdrsiz: SA with null xform")); 143 if (sav->flags & SADB_X_EXT_OLD) 144 size = sizeof (struct esp); 145 else 146 size = sizeof (struct newesp); 147 size += sav->tdb_encalgxform->blocksize + 9; 148 /*XXX need alg check???*/ 149 if (sav->tdb_authalgxform != NULL && sav->replay) 150 size += ah_hdrsiz(sav); 151 } else { 152 /* 153 * base header size 154 * + max iv length for CBC mode 155 * + max pad length 156 * + sizeof (pad length field) 157 * + sizeof (next header field) 158 * + max icv supported. 159 */ 160 size = sizeof (struct newesp) + esp_max_ivlen + 9 + 16; 161 } 162 return size; 163 } 164 165 /* 166 * esp_init() is called when an SPI is being set up. 167 */ 168 static int 169 esp_init(struct secasvar *sav, struct xformsw *xsp) 170 { 171 struct enc_xform *txform; 172 struct cryptoini cria, crie; 173 int keylen; 174 int error; 175 176 txform = esp_algorithm_lookup(sav->alg_enc); 177 if (txform == NULL) { 178 DPRINTF(("esp_init: unsupported encryption algorithm %d\n", 179 sav->alg_enc)); 180 return EINVAL; 181 } 182 if (sav->key_enc == NULL) { 183 DPRINTF(("esp_init: no encoding key for %s algorithm\n", 184 txform->name)); 185 return EINVAL; 186 } 187 if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) { 188 DPRINTF(("esp_init: 4-byte IV not supported with protocol\n")); 189 return EINVAL; 190 } 191 keylen = _KEYLEN(sav->key_enc); 192 if (txform->minkey > keylen || keylen > txform->maxkey) { 193 DPRINTF(("esp_init: invalid key length %u, must be in " 194 "the range [%u..%u] for algorithm %s\n", 195 keylen, txform->minkey, txform->maxkey, 196 txform->name)); 197 return EINVAL; 198 } 199 200 /* 201 * NB: The null xform needs a non-zero blocksize to keep the 202 * crypto code happy but if we use it to set ivlen then 203 * the ESP header will be processed incorrectly. The 204 * compromise is to force it to zero here. 205 */ 206 sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize); 207 sav->iv = malloc(sav->ivlen, M_SECA, M_WAITOK); 208 if (sav->iv == NULL) { 209 DPRINTF(("esp_init: no memory for IV\n")); 210 return EINVAL; 211 } 212 key_randomfill(sav->iv, sav->ivlen); /*XXX*/ 213 214 /* 215 * Setup AH-related state. 216 */ 217 if (sav->alg_auth != 0) { 218 error = ah_init0(sav, xsp, &cria); 219 if (error) 220 return error; 221 } 222 223 /* NB: override anything set in ah_init0 */ 224 sav->tdb_xform = xsp; 225 sav->tdb_encalgxform = txform; 226 227 /* Initialize crypto session. */ 228 bzero(&crie, sizeof (crie)); 229 crie.cri_alg = sav->tdb_encalgxform->type; 230 crie.cri_klen = _KEYBITS(sav->key_enc); 231 crie.cri_key = _KEYBUF(sav->key_enc); 232 /* XXX Rounds ? */ 233 234 mutex_spin_enter(&crypto_mtx); 235 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 236 /* init both auth & enc */ 237 crie.cri_next = &cria; 238 error = crypto_newsession(&sav->tdb_cryptoid, 239 &crie, crypto_support); 240 } else if (sav->tdb_encalgxform) { 241 error = crypto_newsession(&sav->tdb_cryptoid, 242 &crie, crypto_support); 243 } else if (sav->tdb_authalgxform) { 244 error = crypto_newsession(&sav->tdb_cryptoid, 245 &cria, crypto_support); 246 } else { 247 /* XXX cannot happen? */ 248 DPRINTF(("esp_init: no encoding OR authentication xform!\n")); 249 error = EINVAL; 250 } 251 mutex_spin_exit(&crypto_mtx); 252 return error; 253 } 254 255 /* 256 * Paranoia. 257 */ 258 static int 259 esp_zeroize(struct secasvar *sav) 260 { 261 /* NB: ah_zerorize free's the crypto session state */ 262 int error = ah_zeroize(sav); 263 264 if (sav->key_enc) 265 bzero(_KEYBUF(sav->key_enc), _KEYLEN(sav->key_enc)); 266 /* NB: sav->iv is freed elsewhere, even though we malloc it! */ 267 sav->tdb_encalgxform = NULL; 268 sav->tdb_xform = NULL; 269 return error; 270 } 271 272 /* 273 * ESP input processing, called (eventually) through the protocol switch. 274 */ 275 static int 276 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 277 { 278 struct auth_hash *esph; 279 struct enc_xform *espx; 280 struct tdb_ident *tdbi; 281 struct tdb_crypto *tc; 282 int plen, alen, hlen; 283 struct m_tag *mtag; 284 struct newesp *esp; 285 286 struct cryptodesc *crde; 287 struct cryptop *crp; 288 289 IPSEC_SPLASSERT_SOFTNET("esp_input"); 290 291 IPSEC_ASSERT(sav != NULL, ("esp_input: null SA")); 292 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 293 ("esp_input: null encoding xform")); 294 IPSEC_ASSERT((skip&3) == 0 && (m->m_pkthdr.len&3) == 0, 295 ("esp_input: misaligned packet, skip %u pkt len %u", 296 skip, m->m_pkthdr.len)); 297 298 /* XXX don't pullup, just copy header */ 299 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 300 301 esph = sav->tdb_authalgxform; 302 espx = sav->tdb_encalgxform; 303 304 /* Determine the ESP header length */ 305 if (sav->flags & SADB_X_EXT_OLD) 306 hlen = sizeof (struct esp) + sav->ivlen; 307 else 308 hlen = sizeof (struct newesp) + sav->ivlen; 309 /* Authenticator hash size */ 310 alen = esph ? AH_HMAC_HASHLEN : 0; 311 312 /* 313 * Verify payload length is multiple of encryption algorithm 314 * block size. 315 * 316 * NB: This works for the null algorithm because the blocksize 317 * is 4 and all packets must be 4-byte aligned regardless 318 * of the algorithm. 319 */ 320 plen = m->m_pkthdr.len - (skip + hlen + alen); 321 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 322 DPRINTF(("esp_input: " 323 "payload of %d octets not a multiple of %d octets," 324 " SA %s/%08lx\n", 325 plen, espx->blocksize, 326 ipsec_address(&sav->sah->saidx.dst), 327 (u_long) ntohl(sav->spi))); 328 espstat.esps_badilen++; 329 m_freem(m); 330 return EINVAL; 331 } 332 333 /* 334 * Check sequence number. 335 */ 336 if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) { 337 DPRINTF(("esp_input: packet replay check for %s\n", 338 ipsec_logsastr(sav))); /*XXX*/ 339 espstat.esps_replay++; 340 m_freem(m); 341 return ENOBUFS; /*XXX*/ 342 } 343 344 /* Update the counters */ 345 espstat.esps_ibytes += m->m_pkthdr.len - skip - hlen - alen; 346 347 /* Find out if we've already done crypto */ 348 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL); 349 mtag != NULL; 350 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) { 351 tdbi = (struct tdb_ident *) (mtag + 1); 352 if (tdbi->proto == sav->sah->saidx.proto && 353 tdbi->spi == sav->spi && 354 !bcmp(&tdbi->dst, &sav->sah->saidx.dst, 355 sizeof(union sockaddr_union))) 356 break; 357 } 358 359 /* Get crypto descriptors */ 360 crp = crypto_getreq(esph && espx ? 2 : 1); 361 if (crp == NULL) { 362 DPRINTF(("esp_input: failed to acquire crypto descriptors\n")); 363 espstat.esps_crypto++; 364 m_freem(m); 365 return ENOBUFS; 366 } 367 368 /* Get IPsec-specific opaque pointer */ 369 if (esph == NULL || mtag != NULL) 370 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 371 M_XDATA, M_NOWAIT|M_ZERO); 372 else 373 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen, 374 M_XDATA, M_NOWAIT|M_ZERO); 375 if (tc == NULL) { 376 crypto_freereq(crp); 377 DPRINTF(("esp_input: failed to allocate tdb_crypto\n")); 378 espstat.esps_crypto++; 379 m_freem(m); 380 return ENOBUFS; 381 } 382 383 tc->tc_ptr = mtag; 384 385 if (esph) { 386 struct cryptodesc *crda = crp->crp_desc; 387 388 IPSEC_ASSERT(crda != NULL, ("esp_input: null ah crypto descriptor")); 389 390 /* Authentication descriptor */ 391 crda->crd_skip = skip; 392 crda->crd_len = m->m_pkthdr.len - (skip + alen); 393 crda->crd_inject = m->m_pkthdr.len - alen; 394 395 crda->crd_alg = esph->type; 396 crda->crd_key = _KEYBUF(sav->key_auth); 397 crda->crd_klen = _KEYBITS(sav->key_auth); 398 399 /* Copy the authenticator */ 400 if (mtag == NULL) 401 m_copydata(m, m->m_pkthdr.len - alen, alen, 402 (tc + 1)); 403 404 /* Chain authentication request */ 405 crde = crda->crd_next; 406 } else { 407 crde = crp->crp_desc; 408 } 409 410 /* Crypto operation descriptor */ 411 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 412 crp->crp_flags = CRYPTO_F_IMBUF; 413 crp->crp_buf = m; 414 crp->crp_callback = esp_input_cb; 415 crp->crp_sid = sav->tdb_cryptoid; 416 crp->crp_opaque = tc; 417 418 /* These are passed as-is to the callback */ 419 tc->tc_spi = sav->spi; 420 tc->tc_dst = sav->sah->saidx.dst; 421 tc->tc_proto = sav->sah->saidx.proto; 422 tc->tc_protoff = protoff; 423 tc->tc_skip = skip; 424 425 /* Decryption descriptor */ 426 if (espx) { 427 IPSEC_ASSERT(crde != NULL, ("esp_input: null esp crypto descriptor")); 428 crde->crd_skip = skip + hlen; 429 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 430 crde->crd_inject = skip + hlen - sav->ivlen; 431 432 crde->crd_alg = espx->type; 433 crde->crd_key = _KEYBUF(sav->key_enc); 434 crde->crd_klen = _KEYBITS(sav->key_enc); 435 /* XXX Rounds ? */ 436 } 437 438 if (mtag == NULL) 439 return crypto_dispatch(crp); 440 else 441 return esp_input_cb(crp); 442 } 443 444 #ifdef INET6 445 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \ 446 if (saidx->dst.sa.sa_family == AF_INET6) { \ 447 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \ 448 } else { \ 449 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \ 450 } \ 451 } while (0) 452 #else 453 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \ 454 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag)) 455 #endif 456 457 /* 458 * ESP input callback from the crypto driver. 459 */ 460 static int 461 esp_input_cb(struct cryptop *crp) 462 { 463 u_int8_t lastthree[3], aalg[AH_HMAC_HASHLEN]; 464 int s, hlen, skip, protoff, error; 465 struct mbuf *m; 466 struct cryptodesc *crd; 467 struct auth_hash *esph; 468 struct enc_xform *espx; 469 struct tdb_crypto *tc; 470 struct m_tag *mtag; 471 struct secasvar *sav; 472 struct secasindex *saidx; 473 void *ptr; 474 u_int16_t dport = 0; 475 u_int16_t sport = 0; 476 #ifdef IPSEC_NAT_T 477 struct m_tag * tag = NULL; 478 #endif 479 480 crd = crp->crp_desc; 481 IPSEC_ASSERT(crd != NULL, ("esp_input_cb: null crypto descriptor!")); 482 483 tc = (struct tdb_crypto *) crp->crp_opaque; 484 IPSEC_ASSERT(tc != NULL, ("esp_input_cb: null opaque crypto data area!")); 485 skip = tc->tc_skip; 486 protoff = tc->tc_protoff; 487 mtag = (struct m_tag *) tc->tc_ptr; 488 m = (struct mbuf *) crp->crp_buf; 489 490 #ifdef IPSEC_NAT_T 491 /* find the source port for NAT-T */ 492 if ((tag = m_tag_find(m, PACKET_TAG_IPSEC_NAT_T_PORTS, NULL))) { 493 sport = ((u_int16_t *)(tag + 1))[0]; 494 dport = ((u_int16_t *)(tag + 1))[1]; 495 } 496 #endif 497 498 s = splsoftnet(); 499 500 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi, sport, dport); 501 if (sav == NULL) { 502 espstat.esps_notdb++; 503 DPRINTF(("esp_input_cb: SA expired while in crypto " 504 "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst), 505 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 506 error = ENOBUFS; /*XXX*/ 507 goto bad; 508 } 509 510 saidx = &sav->sah->saidx; 511 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 512 saidx->dst.sa.sa_family == AF_INET6, 513 ("ah_input_cb: unexpected protocol family %u", 514 saidx->dst.sa.sa_family)); 515 516 esph = sav->tdb_authalgxform; 517 espx = sav->tdb_encalgxform; 518 519 /* Check for crypto errors */ 520 if (crp->crp_etype) { 521 /* Reset the session ID */ 522 if (sav->tdb_cryptoid != 0) 523 sav->tdb_cryptoid = crp->crp_sid; 524 525 if (crp->crp_etype == EAGAIN) { 526 KEY_FREESAV(&sav); 527 splx(s); 528 return crypto_dispatch(crp); 529 } 530 531 espstat.esps_noxform++; 532 DPRINTF(("esp_input_cb: crypto error %d\n", crp->crp_etype)); 533 error = crp->crp_etype; 534 goto bad; 535 } 536 537 /* Shouldn't happen... */ 538 if (m == NULL) { 539 espstat.esps_crypto++; 540 DPRINTF(("esp_input_cb: bogus returned buffer from crypto\n")); 541 error = EINVAL; 542 goto bad; 543 } 544 espstat.esps_hist[sav->alg_enc]++; 545 546 /* If authentication was performed, check now. */ 547 if (esph != NULL) { 548 /* 549 * If we have a tag, it means an IPsec-aware NIC did 550 * the verification for us. Otherwise we need to 551 * check the authentication calculation. 552 */ 553 ahstat.ahs_hist[sav->alg_auth]++; 554 if (mtag == NULL) { 555 /* Copy the authenticator from the packet */ 556 m_copydata(m, m->m_pkthdr.len - esph->authsize, 557 esph->authsize, aalg); 558 559 ptr = (tc + 1); 560 561 /* Verify authenticator */ 562 if (bcmp(ptr, aalg, esph->authsize) != 0) { 563 DPRINTF(("esp_input_cb: " 564 "authentication hash mismatch for packet in SA %s/%08lx\n", 565 ipsec_address(&saidx->dst), 566 (u_long) ntohl(sav->spi))); 567 espstat.esps_badauth++; 568 error = EACCES; 569 goto bad; 570 } 571 } 572 573 /* Remove trailing authenticator */ 574 m_adj(m, -(esph->authsize)); 575 } 576 577 /* Release the crypto descriptors */ 578 free(tc, M_XDATA), tc = NULL; 579 crypto_freereq(crp), crp = NULL; 580 581 /* 582 * Packet is now decrypted. 583 */ 584 m->m_flags |= M_DECRYPTED; 585 586 /* 587 * Update replay sequence number, if appropriate. 588 */ 589 if (sav->replay) { 590 u_int32_t seq; 591 592 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 593 sizeof (seq), &seq); 594 if (ipsec_updatereplay(ntohl(seq), sav)) { 595 DPRINTF(("%s: packet replay check for %s\n", __func__, 596 ipsec_logsastr(sav))); 597 espstat.esps_replay++; 598 error = ENOBUFS; 599 goto bad; 600 } 601 } 602 603 /* Determine the ESP header length */ 604 if (sav->flags & SADB_X_EXT_OLD) 605 hlen = sizeof (struct esp) + sav->ivlen; 606 else 607 hlen = sizeof (struct newesp) + sav->ivlen; 608 609 /* Remove the ESP header and IV from the mbuf. */ 610 error = m_striphdr(m, skip, hlen); 611 if (error) { 612 espstat.esps_hdrops++; 613 DPRINTF(("esp_input_cb: bad mbuf chain, SA %s/%08lx\n", 614 ipsec_address(&sav->sah->saidx.dst), 615 (u_long) ntohl(sav->spi))); 616 goto bad; 617 } 618 619 /* Save the last three bytes of decrypted data */ 620 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 621 622 /* Verify pad length */ 623 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 624 espstat.esps_badilen++; 625 DPRINTF(("esp_input_cb: invalid padding length %d " 626 "for %u byte packet in SA %s/%08lx\n", 627 lastthree[1], m->m_pkthdr.len - skip, 628 ipsec_address(&sav->sah->saidx.dst), 629 (u_long) ntohl(sav->spi))); 630 error = EINVAL; 631 goto bad; 632 } 633 634 /* Verify correct decryption by checking the last padding bytes */ 635 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 636 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 637 espstat.esps_badenc++; 638 DPRINTF(("esp_input_cb: decryption failed " 639 "for packet in SA %s/%08lx\n", 640 ipsec_address(&sav->sah->saidx.dst), 641 (u_long) ntohl(sav->spi))); 642 DPRINTF(("esp_input_cb: %x %x\n", lastthree[0], lastthree[1])); 643 error = EINVAL; 644 goto bad; 645 } 646 } 647 648 /* Trim the mbuf chain to remove trailing authenticator and padding */ 649 m_adj(m, -(lastthree[1] + 2)); 650 651 /* Restore the Next Protocol field */ 652 m = m_copyback_cow(m, protoff, sizeof (u_int8_t), lastthree + 2, 653 M_DONTWAIT); 654 655 if (m == NULL) { 656 espstat.esps_crypto++; 657 DPRINTF(("esp_input_cb: failed to allocate mbuf\n")); 658 error = ENOBUFS; 659 goto bad; 660 } 661 662 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag); 663 664 KEY_FREESAV(&sav); 665 splx(s); 666 return error; 667 bad: 668 if (sav) 669 KEY_FREESAV(&sav); 670 splx(s); 671 if (m != NULL) 672 m_freem(m); 673 if (tc != NULL) 674 free(tc, M_XDATA); 675 if (crp != NULL) 676 crypto_freereq(crp); 677 return error; 678 } 679 680 /* 681 * ESP output routine, called by ipsec[46]_process_packet(). 682 */ 683 static int 684 esp_output( 685 struct mbuf *m, 686 struct ipsecrequest *isr, 687 struct mbuf **mp, 688 int skip, 689 int protoff 690 ) 691 { 692 struct enc_xform *espx; 693 struct auth_hash *esph; 694 int hlen, rlen, plen, padding, blks, alen, i, roff; 695 struct mbuf *mo = (struct mbuf *) NULL; 696 struct tdb_crypto *tc; 697 struct secasvar *sav; 698 struct secasindex *saidx; 699 unsigned char *pad; 700 u_int8_t prot; 701 int error, maxpacketsize; 702 703 struct cryptodesc *crde = NULL, *crda = NULL; 704 struct cryptop *crp; 705 706 IPSEC_SPLASSERT_SOFTNET("esp_output"); 707 708 sav = isr->sav; 709 IPSEC_ASSERT(sav != NULL, ("esp_output: null SA")); 710 esph = sav->tdb_authalgxform; 711 espx = sav->tdb_encalgxform; 712 IPSEC_ASSERT(espx != NULL, ("esp_output: null encoding xform")); 713 714 if (sav->flags & SADB_X_EXT_OLD) 715 hlen = sizeof (struct esp) + sav->ivlen; 716 else 717 hlen = sizeof (struct newesp) + sav->ivlen; 718 719 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 720 /* 721 * NB: The null encoding transform has a blocksize of 4 722 * so that headers are properly aligned. 723 */ 724 blks = espx->blocksize; /* IV blocksize */ 725 726 /* XXX clamp padding length a la KAME??? */ 727 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 728 plen = rlen + padding; /* Padded payload length. */ 729 730 if (esph) 731 alen = AH_HMAC_HASHLEN; 732 else 733 alen = 0; 734 735 espstat.esps_output++; 736 737 saidx = &sav->sah->saidx; 738 /* Check for maximum packet size violations. */ 739 switch (saidx->dst.sa.sa_family) { 740 #ifdef INET 741 case AF_INET: 742 maxpacketsize = IP_MAXPACKET; 743 break; 744 #endif /* INET */ 745 #ifdef INET6 746 case AF_INET6: 747 maxpacketsize = IPV6_MAXPACKET; 748 break; 749 #endif /* INET6 */ 750 default: 751 DPRINTF(("esp_output: unknown/unsupported protocol " 752 "family %d, SA %s/%08lx\n", 753 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst), 754 (u_long) ntohl(sav->spi))); 755 espstat.esps_nopf++; 756 error = EPFNOSUPPORT; 757 goto bad; 758 } 759 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 760 DPRINTF(("esp_output: packet in SA %s/%08lx got too big " 761 "(len %u, max len %u)\n", 762 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi), 763 skip + hlen + rlen + padding + alen, maxpacketsize)); 764 espstat.esps_toobig++; 765 error = EMSGSIZE; 766 goto bad; 767 } 768 769 /* Update the counters. */ 770 espstat.esps_obytes += m->m_pkthdr.len - skip; 771 772 m = m_clone(m); 773 if (m == NULL) { 774 DPRINTF(("esp_output: cannot clone mbuf chain, SA %s/%08lx\n", 775 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 776 espstat.esps_hdrops++; 777 error = ENOBUFS; 778 goto bad; 779 } 780 781 /* Inject ESP header. */ 782 mo = m_makespace(m, skip, hlen, &roff); 783 if (mo == NULL) { 784 DPRINTF(("esp_output: failed to inject %u byte ESP hdr for SA " 785 "%s/%08lx\n", 786 hlen, ipsec_address(&saidx->dst), 787 (u_long) ntohl(sav->spi))); 788 espstat.esps_hdrops++; /* XXX diffs from openbsd */ 789 error = ENOBUFS; 790 goto bad; 791 } 792 793 /* Initialize ESP header. */ 794 bcopy(&sav->spi, mtod(mo, char *) + roff, sizeof(u_int32_t)); 795 if (sav->replay) { 796 u_int32_t replay; 797 798 #ifdef IPSEC_DEBUG 799 /* Emulate replay attack when ipsec_replay is TRUE. */ 800 if (!ipsec_replay) 801 #endif 802 sav->replay->count++; 803 804 replay = htonl(sav->replay->count); 805 bcopy(&replay, 806 mtod(mo,char *) + roff + sizeof(u_int32_t), 807 sizeof(u_int32_t)); 808 } 809 810 /* 811 * Add padding -- better to do it ourselves than use the crypto engine, 812 * although if/when we support compression, we'd have to do that. 813 */ 814 pad = (u_char *) m_pad(m, padding + alen); 815 if (pad == NULL) { 816 DPRINTF(("esp_output: m_pad failed for SA %s/%08lx\n", 817 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 818 m = NULL; /* NB: free'd by m_pad */ 819 error = ENOBUFS; 820 goto bad; 821 } 822 823 /* 824 * Add padding: random, zero, or self-describing. 825 * XXX catch unexpected setting 826 */ 827 switch (sav->flags & SADB_X_EXT_PMASK) { 828 case SADB_X_EXT_PRAND: 829 (void) read_random(pad, padding - 2); 830 break; 831 case SADB_X_EXT_PZERO: 832 bzero(pad, padding - 2); 833 break; 834 case SADB_X_EXT_PSEQ: 835 for (i = 0; i < padding - 2; i++) 836 pad[i] = i+1; 837 break; 838 } 839 840 /* Fix padding length and Next Protocol in padding itself. */ 841 pad[padding - 2] = padding - 2; 842 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 843 844 /* Fix Next Protocol in IPv4/IPv6 header. */ 845 prot = IPPROTO_ESP; 846 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 847 848 /* Get crypto descriptors. */ 849 crp = crypto_getreq(esph && espx ? 2 : 1); 850 if (crp == NULL) { 851 DPRINTF(("esp_output: failed to acquire crypto descriptors\n")); 852 espstat.esps_crypto++; 853 error = ENOBUFS; 854 goto bad; 855 } 856 857 if (espx) { 858 crde = crp->crp_desc; 859 crda = crde->crd_next; 860 861 /* Encryption descriptor. */ 862 crde->crd_skip = skip + hlen; 863 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 864 crde->crd_flags = CRD_F_ENCRYPT; 865 crde->crd_inject = skip + hlen - sav->ivlen; 866 867 /* Encryption operation. */ 868 crde->crd_alg = espx->type; 869 crde->crd_key = _KEYBUF(sav->key_enc); 870 crde->crd_klen = _KEYBITS(sav->key_enc); 871 /* XXX Rounds ? */ 872 } else 873 crda = crp->crp_desc; 874 875 /* IPsec-specific opaque crypto info. */ 876 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 877 M_XDATA, M_NOWAIT|M_ZERO); 878 if (tc == NULL) { 879 crypto_freereq(crp); 880 DPRINTF(("esp_output: failed to allocate tdb_crypto\n")); 881 espstat.esps_crypto++; 882 error = ENOBUFS; 883 goto bad; 884 } 885 886 /* Callback parameters */ 887 tc->tc_isr = isr; 888 tc->tc_spi = sav->spi; 889 tc->tc_dst = saidx->dst; 890 tc->tc_proto = saidx->proto; 891 892 /* Crypto operation descriptor. */ 893 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 894 crp->crp_flags = CRYPTO_F_IMBUF; 895 crp->crp_buf = m; 896 crp->crp_callback = esp_output_cb; 897 crp->crp_opaque = tc; 898 crp->crp_sid = sav->tdb_cryptoid; 899 900 if (esph) { 901 /* Authentication descriptor. */ 902 crda->crd_skip = skip; 903 crda->crd_len = m->m_pkthdr.len - (skip + alen); 904 crda->crd_inject = m->m_pkthdr.len - alen; 905 906 /* Authentication operation. */ 907 crda->crd_alg = esph->type; 908 crda->crd_key = _KEYBUF(sav->key_auth); 909 crda->crd_klen = _KEYBITS(sav->key_auth); 910 } 911 912 return crypto_dispatch(crp); 913 bad: 914 if (m) 915 m_freem(m); 916 return (error); 917 } 918 919 /* 920 * ESP output callback from the crypto driver. 921 */ 922 static int 923 esp_output_cb(struct cryptop *crp) 924 { 925 struct tdb_crypto *tc; 926 struct ipsecrequest *isr; 927 struct secasvar *sav; 928 struct mbuf *m; 929 int s, err, error; 930 931 tc = (struct tdb_crypto *) crp->crp_opaque; 932 IPSEC_ASSERT(tc != NULL, ("esp_output_cb: null opaque data area!")); 933 m = (struct mbuf *) crp->crp_buf; 934 935 s = splsoftnet(); 936 937 isr = tc->tc_isr; 938 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi, 0, 0); 939 if (sav == NULL) { 940 espstat.esps_notdb++; 941 DPRINTF(("esp_output_cb: SA expired while in crypto " 942 "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst), 943 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 944 error = ENOBUFS; /*XXX*/ 945 goto bad; 946 } 947 IPSEC_ASSERT(isr->sav == sav, 948 ("esp_output_cb: SA changed was %p now %p\n", isr->sav, sav)); 949 950 /* Check for crypto errors. */ 951 if (crp->crp_etype) { 952 /* Reset session ID. */ 953 if (sav->tdb_cryptoid != 0) 954 sav->tdb_cryptoid = crp->crp_sid; 955 956 if (crp->crp_etype == EAGAIN) { 957 KEY_FREESAV(&sav); 958 splx(s); 959 return crypto_dispatch(crp); 960 } 961 962 espstat.esps_noxform++; 963 DPRINTF(("esp_output_cb: crypto error %d\n", crp->crp_etype)); 964 error = crp->crp_etype; 965 goto bad; 966 } 967 968 /* Shouldn't happen... */ 969 if (m == NULL) { 970 espstat.esps_crypto++; 971 DPRINTF(("esp_output_cb: bogus returned buffer from crypto\n")); 972 error = EINVAL; 973 goto bad; 974 } 975 espstat.esps_hist[sav->alg_enc]++; 976 if (sav->tdb_authalgxform != NULL) 977 ahstat.ahs_hist[sav->alg_auth]++; 978 979 /* Release crypto descriptors. */ 980 free(tc, M_XDATA); 981 crypto_freereq(crp); 982 983 #ifdef IPSEC_DEBUG 984 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 985 if (ipsec_integrity) { 986 static unsigned char ipseczeroes[AH_HMAC_HASHLEN]; 987 struct auth_hash *esph; 988 989 /* 990 * Corrupt HMAC if we want to test integrity verification of 991 * the other side. 992 */ 993 esph = sav->tdb_authalgxform; 994 if (esph != NULL) { 995 m_copyback(m, m->m_pkthdr.len - AH_HMAC_HASHLEN, 996 AH_HMAC_HASHLEN, ipseczeroes); 997 } 998 } 999 #endif 1000 1001 /* NB: m is reclaimed by ipsec_process_done. */ 1002 err = ipsec_process_done(m, isr); 1003 KEY_FREESAV(&sav); 1004 splx(s); 1005 return err; 1006 bad: 1007 if (sav) 1008 KEY_FREESAV(&sav); 1009 splx(s); 1010 if (m) 1011 m_freem(m); 1012 free(tc, M_XDATA); 1013 crypto_freereq(crp); 1014 return error; 1015 } 1016 1017 static struct xformsw esp_xformsw = { 1018 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 1019 esp_init, esp_zeroize, esp_input, 1020 esp_output, 1021 NULL, 1022 }; 1023 1024 INITFN void 1025 esp_attach(void) 1026 { 1027 #define MAXIV(xform) \ 1028 if (xform.blocksize > esp_max_ivlen) \ 1029 esp_max_ivlen = xform.blocksize \ 1030 1031 esp_max_ivlen = 0; 1032 MAXIV(enc_xform_des); /* SADB_EALG_DESCBC */ 1033 MAXIV(enc_xform_3des); /* SADB_EALG_3DESCBC */ 1034 MAXIV(enc_xform_rijndael128); /* SADB_X_EALG_AES */ 1035 MAXIV(enc_xform_blf); /* SADB_X_EALG_BLOWFISHCBC */ 1036 MAXIV(enc_xform_cast5); /* SADB_X_EALG_CAST128CBC */ 1037 MAXIV(enc_xform_skipjack); /* SADB_X_EALG_SKIPJACK */ 1038 MAXIV(enc_xform_null); /* SADB_EALG_NULL */ 1039 1040 xform_register(&esp_xformsw); 1041 #undef MAXIV 1042 } 1043 #ifdef __FreeBSD__ 1044 SYSINIT(esp_xform_init, SI_SUB_DRIVERS, SI_ORDER_FIRST, esp_attach, NULL) 1045 #else 1046 #endif 1047