1 /* $NetBSD: xform_esp.c,v 1.16 2007/06/27 20:38:33 degroote 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 1.16 2007/06/27 20:38:33 degroote 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 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 235 /* init both auth & enc */ 236 crie.cri_next = &cria; 237 error = crypto_newsession(&sav->tdb_cryptoid, 238 &crie, crypto_support); 239 } else if (sav->tdb_encalgxform) { 240 error = crypto_newsession(&sav->tdb_cryptoid, 241 &crie, crypto_support); 242 } else if (sav->tdb_authalgxform) { 243 error = crypto_newsession(&sav->tdb_cryptoid, 244 &cria, crypto_support); 245 } else { 246 /* XXX cannot happen? */ 247 DPRINTF(("esp_init: no encoding OR authentication xform!\n")); 248 error = EINVAL; 249 } 250 return error; 251 } 252 253 /* 254 * Paranoia. 255 */ 256 static int 257 esp_zeroize(struct secasvar *sav) 258 { 259 /* NB: ah_zerorize free's the crypto session state */ 260 int error = ah_zeroize(sav); 261 262 if (sav->key_enc) 263 bzero(_KEYBUF(sav->key_enc), _KEYLEN(sav->key_enc)); 264 /* NB: sav->iv is freed elsewhere, even though we malloc it! */ 265 sav->tdb_encalgxform = NULL; 266 sav->tdb_xform = NULL; 267 return error; 268 } 269 270 /* 271 * ESP input processing, called (eventually) through the protocol switch. 272 */ 273 static int 274 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 275 { 276 struct auth_hash *esph; 277 struct enc_xform *espx; 278 struct tdb_ident *tdbi; 279 struct tdb_crypto *tc; 280 int plen, alen, hlen; 281 struct m_tag *mtag; 282 struct newesp *esp; 283 284 struct cryptodesc *crde; 285 struct cryptop *crp; 286 287 IPSEC_SPLASSERT_SOFTNET("esp_input"); 288 289 IPSEC_ASSERT(sav != NULL, ("esp_input: null SA")); 290 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 291 ("esp_input: null encoding xform")); 292 IPSEC_ASSERT((skip&3) == 0 && (m->m_pkthdr.len&3) == 0, 293 ("esp_input: misaligned packet, skip %u pkt len %u", 294 skip, m->m_pkthdr.len)); 295 296 /* XXX don't pullup, just copy header */ 297 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 298 299 esph = sav->tdb_authalgxform; 300 espx = sav->tdb_encalgxform; 301 302 /* Determine the ESP header length */ 303 if (sav->flags & SADB_X_EXT_OLD) 304 hlen = sizeof (struct esp) + sav->ivlen; 305 else 306 hlen = sizeof (struct newesp) + sav->ivlen; 307 /* Authenticator hash size */ 308 alen = esph ? AH_HMAC_HASHLEN : 0; 309 310 /* 311 * Verify payload length is multiple of encryption algorithm 312 * block size. 313 * 314 * NB: This works for the null algorithm because the blocksize 315 * is 4 and all packets must be 4-byte aligned regardless 316 * of the algorithm. 317 */ 318 plen = m->m_pkthdr.len - (skip + hlen + alen); 319 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 320 DPRINTF(("esp_input: " 321 "payload of %d octets not a multiple of %d octets," 322 " SA %s/%08lx\n", 323 plen, espx->blocksize, 324 ipsec_address(&sav->sah->saidx.dst), 325 (u_long) ntohl(sav->spi))); 326 espstat.esps_badilen++; 327 m_freem(m); 328 return EINVAL; 329 } 330 331 /* 332 * Check sequence number. 333 */ 334 if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) { 335 DPRINTF(("esp_input: packet replay check for %s\n", 336 ipsec_logsastr(sav))); /*XXX*/ 337 espstat.esps_replay++; 338 m_freem(m); 339 return ENOBUFS; /*XXX*/ 340 } 341 342 /* Update the counters */ 343 espstat.esps_ibytes += m->m_pkthdr.len - skip - hlen - alen; 344 345 /* Find out if we've already done crypto */ 346 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL); 347 mtag != NULL; 348 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) { 349 tdbi = (struct tdb_ident *) (mtag + 1); 350 if (tdbi->proto == sav->sah->saidx.proto && 351 tdbi->spi == sav->spi && 352 !bcmp(&tdbi->dst, &sav->sah->saidx.dst, 353 sizeof(union sockaddr_union))) 354 break; 355 } 356 357 /* Get crypto descriptors */ 358 crp = crypto_getreq(esph && espx ? 2 : 1); 359 if (crp == NULL) { 360 DPRINTF(("esp_input: failed to acquire crypto descriptors\n")); 361 espstat.esps_crypto++; 362 m_freem(m); 363 return ENOBUFS; 364 } 365 366 /* Get IPsec-specific opaque pointer */ 367 if (esph == NULL || mtag != NULL) 368 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 369 M_XDATA, M_NOWAIT|M_ZERO); 370 else 371 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen, 372 M_XDATA, M_NOWAIT|M_ZERO); 373 if (tc == NULL) { 374 crypto_freereq(crp); 375 DPRINTF(("esp_input: failed to allocate tdb_crypto\n")); 376 espstat.esps_crypto++; 377 m_freem(m); 378 return ENOBUFS; 379 } 380 381 tc->tc_ptr = mtag; 382 383 if (esph) { 384 struct cryptodesc *crda = crp->crp_desc; 385 386 IPSEC_ASSERT(crda != NULL, ("esp_input: null ah crypto descriptor")); 387 388 /* Authentication descriptor */ 389 crda->crd_skip = skip; 390 crda->crd_len = m->m_pkthdr.len - (skip + alen); 391 crda->crd_inject = m->m_pkthdr.len - alen; 392 393 crda->crd_alg = esph->type; 394 crda->crd_key = _KEYBUF(sav->key_auth); 395 crda->crd_klen = _KEYBITS(sav->key_auth); 396 397 /* Copy the authenticator */ 398 if (mtag == NULL) 399 m_copydata(m, m->m_pkthdr.len - alen, alen, 400 (tc + 1)); 401 402 /* Chain authentication request */ 403 crde = crda->crd_next; 404 } else { 405 crde = crp->crp_desc; 406 } 407 408 /* Crypto operation descriptor */ 409 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 410 crp->crp_flags = CRYPTO_F_IMBUF; 411 crp->crp_buf = m; 412 crp->crp_callback = esp_input_cb; 413 crp->crp_sid = sav->tdb_cryptoid; 414 crp->crp_opaque = tc; 415 416 /* These are passed as-is to the callback */ 417 tc->tc_spi = sav->spi; 418 tc->tc_dst = sav->sah->saidx.dst; 419 tc->tc_proto = sav->sah->saidx.proto; 420 tc->tc_protoff = protoff; 421 tc->tc_skip = skip; 422 423 /* Decryption descriptor */ 424 if (espx) { 425 IPSEC_ASSERT(crde != NULL, ("esp_input: null esp crypto descriptor")); 426 crde->crd_skip = skip + hlen; 427 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 428 crde->crd_inject = skip + hlen - sav->ivlen; 429 430 crde->crd_alg = espx->type; 431 crde->crd_key = _KEYBUF(sav->key_enc); 432 crde->crd_klen = _KEYBITS(sav->key_enc); 433 /* XXX Rounds ? */ 434 } 435 436 if (mtag == NULL) 437 return crypto_dispatch(crp); 438 else 439 return esp_input_cb(crp); 440 } 441 442 #ifdef INET6 443 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \ 444 if (saidx->dst.sa.sa_family == AF_INET6) { \ 445 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \ 446 } else { \ 447 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \ 448 } \ 449 } while (0) 450 #else 451 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \ 452 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag)) 453 #endif 454 455 /* 456 * ESP input callback from the crypto driver. 457 */ 458 static int 459 esp_input_cb(struct cryptop *crp) 460 { 461 u_int8_t lastthree[3], aalg[AH_HMAC_HASHLEN]; 462 int s, hlen, skip, protoff, error; 463 struct mbuf *m; 464 struct cryptodesc *crd; 465 struct auth_hash *esph; 466 struct enc_xform *espx; 467 struct tdb_crypto *tc; 468 struct m_tag *mtag; 469 struct secasvar *sav; 470 struct secasindex *saidx; 471 void *ptr; 472 u_int16_t dport = 0; 473 u_int16_t sport = 0; 474 #ifdef IPSEC_NAT_T 475 struct m_tag * tag = NULL; 476 #endif 477 478 crd = crp->crp_desc; 479 IPSEC_ASSERT(crd != NULL, ("esp_input_cb: null crypto descriptor!")); 480 481 tc = (struct tdb_crypto *) crp->crp_opaque; 482 IPSEC_ASSERT(tc != NULL, ("esp_input_cb: null opaque crypto data area!")); 483 skip = tc->tc_skip; 484 protoff = tc->tc_protoff; 485 mtag = (struct m_tag *) tc->tc_ptr; 486 m = (struct mbuf *) crp->crp_buf; 487 488 #ifdef IPSEC_NAT_T 489 /* find the source port for NAT-T */ 490 if ((tag = m_tag_find(m, PACKET_TAG_IPSEC_NAT_T_PORTS, NULL))) { 491 sport = ((u_int16_t *)(tag + 1))[0]; 492 dport = ((u_int16_t *)(tag + 1))[1]; 493 } 494 #endif 495 496 s = splsoftnet(); 497 498 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi, sport, dport); 499 if (sav == NULL) { 500 espstat.esps_notdb++; 501 DPRINTF(("esp_input_cb: SA expired while in crypto " 502 "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst), 503 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 504 error = ENOBUFS; /*XXX*/ 505 goto bad; 506 } 507 508 saidx = &sav->sah->saidx; 509 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 510 saidx->dst.sa.sa_family == AF_INET6, 511 ("ah_input_cb: unexpected protocol family %u", 512 saidx->dst.sa.sa_family)); 513 514 esph = sav->tdb_authalgxform; 515 espx = sav->tdb_encalgxform; 516 517 /* Check for crypto errors */ 518 if (crp->crp_etype) { 519 /* Reset the session ID */ 520 if (sav->tdb_cryptoid != 0) 521 sav->tdb_cryptoid = crp->crp_sid; 522 523 if (crp->crp_etype == EAGAIN) { 524 KEY_FREESAV(&sav); 525 splx(s); 526 return crypto_dispatch(crp); 527 } 528 529 espstat.esps_noxform++; 530 DPRINTF(("esp_input_cb: crypto error %d\n", crp->crp_etype)); 531 error = crp->crp_etype; 532 goto bad; 533 } 534 535 /* Shouldn't happen... */ 536 if (m == NULL) { 537 espstat.esps_crypto++; 538 DPRINTF(("esp_input_cb: bogus returned buffer from crypto\n")); 539 error = EINVAL; 540 goto bad; 541 } 542 espstat.esps_hist[sav->alg_enc]++; 543 544 /* If authentication was performed, check now. */ 545 if (esph != NULL) { 546 /* 547 * If we have a tag, it means an IPsec-aware NIC did 548 * the verification for us. Otherwise we need to 549 * check the authentication calculation. 550 */ 551 ahstat.ahs_hist[sav->alg_auth]++; 552 if (mtag == NULL) { 553 /* Copy the authenticator from the packet */ 554 m_copydata(m, m->m_pkthdr.len - esph->authsize, 555 esph->authsize, aalg); 556 557 ptr = (tc + 1); 558 559 /* Verify authenticator */ 560 if (bcmp(ptr, aalg, esph->authsize) != 0) { 561 DPRINTF(("esp_input_cb: " 562 "authentication hash mismatch for packet in SA %s/%08lx\n", 563 ipsec_address(&saidx->dst), 564 (u_long) ntohl(sav->spi))); 565 espstat.esps_badauth++; 566 error = EACCES; 567 goto bad; 568 } 569 } 570 571 /* Remove trailing authenticator */ 572 m_adj(m, -(esph->authsize)); 573 } 574 575 /* Release the crypto descriptors */ 576 free(tc, M_XDATA), tc = NULL; 577 crypto_freereq(crp), crp = NULL; 578 579 /* 580 * Packet is now decrypted. 581 */ 582 m->m_flags |= M_DECRYPTED; 583 584 /* 585 * Update replay sequence number, if appropriate. 586 */ 587 if (sav->replay) { 588 u_int32_t seq; 589 590 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 591 sizeof (seq), &seq); 592 if (ipsec_updatereplay(ntohl(seq), sav)) { 593 DPRINTF(("%s: packet replay check for %s\n", __func__, 594 ipsec_logsastr(sav))); 595 espstat.esps_replay++; 596 error = ENOBUFS; 597 goto bad; 598 } 599 } 600 601 /* Determine the ESP header length */ 602 if (sav->flags & SADB_X_EXT_OLD) 603 hlen = sizeof (struct esp) + sav->ivlen; 604 else 605 hlen = sizeof (struct newesp) + sav->ivlen; 606 607 /* Remove the ESP header and IV from the mbuf. */ 608 error = m_striphdr(m, skip, hlen); 609 if (error) { 610 espstat.esps_hdrops++; 611 DPRINTF(("esp_input_cb: bad mbuf chain, SA %s/%08lx\n", 612 ipsec_address(&sav->sah->saidx.dst), 613 (u_long) ntohl(sav->spi))); 614 goto bad; 615 } 616 617 /* Save the last three bytes of decrypted data */ 618 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 619 620 /* Verify pad length */ 621 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 622 espstat.esps_badilen++; 623 DPRINTF(("esp_input_cb: invalid padding length %d " 624 "for %u byte packet in SA %s/%08lx\n", 625 lastthree[1], m->m_pkthdr.len - skip, 626 ipsec_address(&sav->sah->saidx.dst), 627 (u_long) ntohl(sav->spi))); 628 error = EINVAL; 629 goto bad; 630 } 631 632 /* Verify correct decryption by checking the last padding bytes */ 633 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 634 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 635 espstat.esps_badenc++; 636 DPRINTF(("esp_input_cb: decryption failed " 637 "for packet in SA %s/%08lx\n", 638 ipsec_address(&sav->sah->saidx.dst), 639 (u_long) ntohl(sav->spi))); 640 DPRINTF(("esp_input_cb: %x %x\n", lastthree[0], lastthree[1])); 641 error = EINVAL; 642 goto bad; 643 } 644 } 645 646 /* Trim the mbuf chain to remove trailing authenticator and padding */ 647 m_adj(m, -(lastthree[1] + 2)); 648 649 /* Restore the Next Protocol field */ 650 m = m_copyback_cow(m, protoff, sizeof (u_int8_t), lastthree + 2, 651 M_DONTWAIT); 652 653 if (m == NULL) { 654 espstat.esps_crypto++; 655 DPRINTF(("esp_input_cb: failed to allocate mbuf\n")); 656 error = ENOBUFS; 657 goto bad; 658 } 659 660 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag); 661 662 KEY_FREESAV(&sav); 663 splx(s); 664 return error; 665 bad: 666 if (sav) 667 KEY_FREESAV(&sav); 668 splx(s); 669 if (m != NULL) 670 m_freem(m); 671 if (tc != NULL) 672 free(tc, M_XDATA); 673 if (crp != NULL) 674 crypto_freereq(crp); 675 return error; 676 } 677 678 /* 679 * ESP output routine, called by ipsec[46]_process_packet(). 680 */ 681 static int 682 esp_output( 683 struct mbuf *m, 684 struct ipsecrequest *isr, 685 struct mbuf **mp, 686 int skip, 687 int protoff 688 ) 689 { 690 struct enc_xform *espx; 691 struct auth_hash *esph; 692 int hlen, rlen, plen, padding, blks, alen, i, roff; 693 struct mbuf *mo = (struct mbuf *) NULL; 694 struct tdb_crypto *tc; 695 struct secasvar *sav; 696 struct secasindex *saidx; 697 unsigned char *pad; 698 u_int8_t prot; 699 int error, maxpacketsize; 700 701 struct cryptodesc *crde = NULL, *crda = NULL; 702 struct cryptop *crp; 703 704 IPSEC_SPLASSERT_SOFTNET("esp_output"); 705 706 sav = isr->sav; 707 IPSEC_ASSERT(sav != NULL, ("esp_output: null SA")); 708 esph = sav->tdb_authalgxform; 709 espx = sav->tdb_encalgxform; 710 IPSEC_ASSERT(espx != NULL, ("esp_output: null encoding xform")); 711 712 if (sav->flags & SADB_X_EXT_OLD) 713 hlen = sizeof (struct esp) + sav->ivlen; 714 else 715 hlen = sizeof (struct newesp) + sav->ivlen; 716 717 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 718 /* 719 * NB: The null encoding transform has a blocksize of 4 720 * so that headers are properly aligned. 721 */ 722 blks = espx->blocksize; /* IV blocksize */ 723 724 /* XXX clamp padding length a la KAME??? */ 725 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 726 plen = rlen + padding; /* Padded payload length. */ 727 728 if (esph) 729 alen = AH_HMAC_HASHLEN; 730 else 731 alen = 0; 732 733 espstat.esps_output++; 734 735 saidx = &sav->sah->saidx; 736 /* Check for maximum packet size violations. */ 737 switch (saidx->dst.sa.sa_family) { 738 #ifdef INET 739 case AF_INET: 740 maxpacketsize = IP_MAXPACKET; 741 break; 742 #endif /* INET */ 743 #ifdef INET6 744 case AF_INET6: 745 maxpacketsize = IPV6_MAXPACKET; 746 break; 747 #endif /* INET6 */ 748 default: 749 DPRINTF(("esp_output: unknown/unsupported protocol " 750 "family %d, SA %s/%08lx\n", 751 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst), 752 (u_long) ntohl(sav->spi))); 753 espstat.esps_nopf++; 754 error = EPFNOSUPPORT; 755 goto bad; 756 } 757 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 758 DPRINTF(("esp_output: packet in SA %s/%08lx got too big " 759 "(len %u, max len %u)\n", 760 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi), 761 skip + hlen + rlen + padding + alen, maxpacketsize)); 762 espstat.esps_toobig++; 763 error = EMSGSIZE; 764 goto bad; 765 } 766 767 /* Update the counters. */ 768 espstat.esps_obytes += m->m_pkthdr.len - skip; 769 770 m = m_clone(m); 771 if (m == NULL) { 772 DPRINTF(("esp_output: cannot clone mbuf chain, SA %s/%08lx\n", 773 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 774 espstat.esps_hdrops++; 775 error = ENOBUFS; 776 goto bad; 777 } 778 779 /* Inject ESP header. */ 780 mo = m_makespace(m, skip, hlen, &roff); 781 if (mo == NULL) { 782 DPRINTF(("esp_output: failed to inject %u byte ESP hdr for SA " 783 "%s/%08lx\n", 784 hlen, ipsec_address(&saidx->dst), 785 (u_long) ntohl(sav->spi))); 786 espstat.esps_hdrops++; /* XXX diffs from openbsd */ 787 error = ENOBUFS; 788 goto bad; 789 } 790 791 /* Initialize ESP header. */ 792 bcopy(&sav->spi, mtod(mo, char *) + roff, sizeof(u_int32_t)); 793 if (sav->replay) { 794 u_int32_t replay; 795 796 #ifdef IPSEC_DEBUG 797 /* Emulate replay attack when ipsec_replay is TRUE. */ 798 if (!ipsec_replay) 799 #endif 800 sav->replay->count++; 801 802 replay = htonl(sav->replay->count); 803 bcopy(&replay, 804 mtod(mo,char *) + roff + sizeof(u_int32_t), 805 sizeof(u_int32_t)); 806 } 807 808 /* 809 * Add padding -- better to do it ourselves than use the crypto engine, 810 * although if/when we support compression, we'd have to do that. 811 */ 812 pad = (u_char *) m_pad(m, padding + alen); 813 if (pad == NULL) { 814 DPRINTF(("esp_output: m_pad failed for SA %s/%08lx\n", 815 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 816 m = NULL; /* NB: free'd by m_pad */ 817 error = ENOBUFS; 818 goto bad; 819 } 820 821 /* 822 * Add padding: random, zero, or self-describing. 823 * XXX catch unexpected setting 824 */ 825 switch (sav->flags & SADB_X_EXT_PMASK) { 826 case SADB_X_EXT_PRAND: 827 (void) read_random(pad, padding - 2); 828 break; 829 case SADB_X_EXT_PZERO: 830 bzero(pad, padding - 2); 831 break; 832 case SADB_X_EXT_PSEQ: 833 for (i = 0; i < padding - 2; i++) 834 pad[i] = i+1; 835 break; 836 } 837 838 /* Fix padding length and Next Protocol in padding itself. */ 839 pad[padding - 2] = padding - 2; 840 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 841 842 /* Fix Next Protocol in IPv4/IPv6 header. */ 843 prot = IPPROTO_ESP; 844 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 845 846 /* Get crypto descriptors. */ 847 crp = crypto_getreq(esph && espx ? 2 : 1); 848 if (crp == NULL) { 849 DPRINTF(("esp_output: failed to acquire crypto descriptors\n")); 850 espstat.esps_crypto++; 851 error = ENOBUFS; 852 goto bad; 853 } 854 855 if (espx) { 856 crde = crp->crp_desc; 857 crda = crde->crd_next; 858 859 /* Encryption descriptor. */ 860 crde->crd_skip = skip + hlen; 861 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 862 crde->crd_flags = CRD_F_ENCRYPT; 863 crde->crd_inject = skip + hlen - sav->ivlen; 864 865 /* Encryption operation. */ 866 crde->crd_alg = espx->type; 867 crde->crd_key = _KEYBUF(sav->key_enc); 868 crde->crd_klen = _KEYBITS(sav->key_enc); 869 /* XXX Rounds ? */ 870 } else 871 crda = crp->crp_desc; 872 873 /* IPsec-specific opaque crypto info. */ 874 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 875 M_XDATA, M_NOWAIT|M_ZERO); 876 if (tc == NULL) { 877 crypto_freereq(crp); 878 DPRINTF(("esp_output: failed to allocate tdb_crypto\n")); 879 espstat.esps_crypto++; 880 error = ENOBUFS; 881 goto bad; 882 } 883 884 /* Callback parameters */ 885 tc->tc_isr = isr; 886 tc->tc_spi = sav->spi; 887 tc->tc_dst = saidx->dst; 888 tc->tc_proto = saidx->proto; 889 890 /* Crypto operation descriptor. */ 891 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 892 crp->crp_flags = CRYPTO_F_IMBUF; 893 crp->crp_buf = m; 894 crp->crp_callback = esp_output_cb; 895 crp->crp_opaque = tc; 896 crp->crp_sid = sav->tdb_cryptoid; 897 898 if (esph) { 899 /* Authentication descriptor. */ 900 crda->crd_skip = skip; 901 crda->crd_len = m->m_pkthdr.len - (skip + alen); 902 crda->crd_inject = m->m_pkthdr.len - alen; 903 904 /* Authentication operation. */ 905 crda->crd_alg = esph->type; 906 crda->crd_key = _KEYBUF(sav->key_auth); 907 crda->crd_klen = _KEYBITS(sav->key_auth); 908 } 909 910 return crypto_dispatch(crp); 911 bad: 912 if (m) 913 m_freem(m); 914 return (error); 915 } 916 917 /* 918 * ESP output callback from the crypto driver. 919 */ 920 static int 921 esp_output_cb(struct cryptop *crp) 922 { 923 struct tdb_crypto *tc; 924 struct ipsecrequest *isr; 925 struct secasvar *sav; 926 struct mbuf *m; 927 int s, err, error; 928 929 tc = (struct tdb_crypto *) crp->crp_opaque; 930 IPSEC_ASSERT(tc != NULL, ("esp_output_cb: null opaque data area!")); 931 m = (struct mbuf *) crp->crp_buf; 932 933 s = splsoftnet(); 934 935 isr = tc->tc_isr; 936 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi, 0, 0); 937 if (sav == NULL) { 938 espstat.esps_notdb++; 939 DPRINTF(("esp_output_cb: SA expired while in crypto " 940 "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst), 941 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 942 error = ENOBUFS; /*XXX*/ 943 goto bad; 944 } 945 IPSEC_ASSERT(isr->sav == sav, 946 ("esp_output_cb: SA changed was %p now %p\n", isr->sav, sav)); 947 948 /* Check for crypto errors. */ 949 if (crp->crp_etype) { 950 /* Reset session ID. */ 951 if (sav->tdb_cryptoid != 0) 952 sav->tdb_cryptoid = crp->crp_sid; 953 954 if (crp->crp_etype == EAGAIN) { 955 KEY_FREESAV(&sav); 956 splx(s); 957 return crypto_dispatch(crp); 958 } 959 960 espstat.esps_noxform++; 961 DPRINTF(("esp_output_cb: crypto error %d\n", crp->crp_etype)); 962 error = crp->crp_etype; 963 goto bad; 964 } 965 966 /* Shouldn't happen... */ 967 if (m == NULL) { 968 espstat.esps_crypto++; 969 DPRINTF(("esp_output_cb: bogus returned buffer from crypto\n")); 970 error = EINVAL; 971 goto bad; 972 } 973 espstat.esps_hist[sav->alg_enc]++; 974 if (sav->tdb_authalgxform != NULL) 975 ahstat.ahs_hist[sav->alg_auth]++; 976 977 /* Release crypto descriptors. */ 978 free(tc, M_XDATA); 979 crypto_freereq(crp); 980 981 #ifdef IPSEC_DEBUG 982 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 983 if (ipsec_integrity) { 984 static unsigned char ipseczeroes[AH_HMAC_HASHLEN]; 985 struct auth_hash *esph; 986 987 /* 988 * Corrupt HMAC if we want to test integrity verification of 989 * the other side. 990 */ 991 esph = sav->tdb_authalgxform; 992 if (esph != NULL) { 993 m_copyback(m, m->m_pkthdr.len - AH_HMAC_HASHLEN, 994 AH_HMAC_HASHLEN, ipseczeroes); 995 } 996 } 997 #endif 998 999 /* NB: m is reclaimed by ipsec_process_done. */ 1000 err = ipsec_process_done(m, isr); 1001 KEY_FREESAV(&sav); 1002 splx(s); 1003 return err; 1004 bad: 1005 if (sav) 1006 KEY_FREESAV(&sav); 1007 splx(s); 1008 if (m) 1009 m_freem(m); 1010 free(tc, M_XDATA); 1011 crypto_freereq(crp); 1012 return error; 1013 } 1014 1015 static struct xformsw esp_xformsw = { 1016 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 1017 esp_init, esp_zeroize, esp_input, 1018 esp_output, 1019 NULL, 1020 }; 1021 1022 INITFN void 1023 esp_attach(void) 1024 { 1025 #define MAXIV(xform) \ 1026 if (xform.blocksize > esp_max_ivlen) \ 1027 esp_max_ivlen = xform.blocksize \ 1028 1029 esp_max_ivlen = 0; 1030 MAXIV(enc_xform_des); /* SADB_EALG_DESCBC */ 1031 MAXIV(enc_xform_3des); /* SADB_EALG_3DESCBC */ 1032 MAXIV(enc_xform_rijndael128); /* SADB_X_EALG_AES */ 1033 MAXIV(enc_xform_blf); /* SADB_X_EALG_BLOWFISHCBC */ 1034 MAXIV(enc_xform_cast5); /* SADB_X_EALG_CAST128CBC */ 1035 MAXIV(enc_xform_skipjack); /* SADB_X_EALG_SKIPJACK */ 1036 MAXIV(enc_xform_null); /* SADB_EALG_NULL */ 1037 1038 xform_register(&esp_xformsw); 1039 #undef MAXIV 1040 } 1041 #ifdef __FreeBSD__ 1042 SYSINIT(esp_xform_init, SI_SUB_DRIVERS, SI_ORDER_FIRST, esp_attach, NULL) 1043 #else 1044 #endif 1045