xform_esp.c revision 190787
1/* $FreeBSD: head/sys/netipsec/xform_esp.c 190787 2009-04-06 22:29:41Z zec $ */ 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#include <sys/vimage.h> 50 51#include <net/if.h> 52 53#include <netinet/in.h> 54#include <netinet/in_systm.h> 55#include <netinet/ip.h> 56#include <netinet/ip_ecn.h> 57#include <netinet/ip6.h> 58 59#include <net/route.h> 60#include <netipsec/ipsec.h> 61#include <netipsec/ah.h> 62#include <netipsec/ah_var.h> 63#include <netipsec/esp.h> 64#include <netipsec/esp_var.h> 65#include <netipsec/xform.h> 66 67#ifdef INET6 68#include <netinet6/ip6_var.h> 69#include <netipsec/ipsec6.h> 70#include <netinet6/ip6_ecn.h> 71#endif 72 73#include <netipsec/key.h> 74#include <netipsec/key_debug.h> 75 76#include <opencrypto/cryptodev.h> 77#include <opencrypto/xform.h> 78 79#ifdef VIMAGE_GLOBALS 80struct espstat espstat; 81static int esp_max_ivlen; /* max iv length over all algorithms */ 82int esp_enable; 83#endif 84 85SYSCTL_DECL(_net_inet_esp); 86SYSCTL_V_INT(V_NET, vnet_ipsec,_net_inet_esp, OID_AUTO, 87 esp_enable, CTLFLAG_RW, esp_enable, 0, ""); 88SYSCTL_V_STRUCT(V_NET, vnet_ipsec, _net_inet_esp, IPSECCTL_STATS, 89 stats, CTLFLAG_RD, espstat, espstat, ""); 90 91static int esp_input_cb(struct cryptop *op); 92static int esp_output_cb(struct cryptop *crp); 93static int esp_iattach(const void *); 94 95/* 96 * NB: this is public for use by the PF_KEY support. 97 * NB: if you add support here; be sure to add code to esp_attach below! 98 */ 99struct enc_xform * 100esp_algorithm_lookup(int alg) 101{ 102 if (alg >= ESP_ALG_MAX) 103 return NULL; 104 switch (alg) { 105 case SADB_EALG_DESCBC: 106 return &enc_xform_des; 107 case SADB_EALG_3DESCBC: 108 return &enc_xform_3des; 109 case SADB_X_EALG_AES: 110 return &enc_xform_rijndael128; 111 case SADB_X_EALG_BLOWFISHCBC: 112 return &enc_xform_blf; 113 case SADB_X_EALG_CAST128CBC: 114 return &enc_xform_cast5; 115 case SADB_X_EALG_SKIPJACK: 116 return &enc_xform_skipjack; 117 case SADB_EALG_NULL: 118 return &enc_xform_null; 119 case SADB_X_EALG_CAMELLIACBC: 120 return &enc_xform_camellia; 121 } 122 return NULL; 123} 124 125size_t 126esp_hdrsiz(struct secasvar *sav) 127{ 128 INIT_VNET_IPSEC(curvnet); 129 size_t size; 130 131 if (sav != NULL) { 132 /*XXX not right for null algorithm--does it matter??*/ 133 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 134 ("SA with null xform")); 135 if (sav->flags & SADB_X_EXT_OLD) 136 size = sizeof (struct esp); 137 else 138 size = sizeof (struct newesp); 139 size += sav->tdb_encalgxform->blocksize + 9; 140 /*XXX need alg check???*/ 141 if (sav->tdb_authalgxform != NULL && sav->replay) 142 size += ah_hdrsiz(sav); 143 } else { 144 /* 145 * base header size 146 * + max iv length for CBC mode 147 * + max pad length 148 * + sizeof (pad length field) 149 * + sizeof (next header field) 150 * + max icv supported. 151 */ 152 size = sizeof (struct newesp) + V_esp_max_ivlen + 9 + 16; 153 } 154 return size; 155} 156 157/* 158 * esp_init() is called when an SPI is being set up. 159 */ 160static int 161esp_init(struct secasvar *sav, struct xformsw *xsp) 162{ 163 INIT_VNET_IPSEC(curvnet); 164 struct enc_xform *txform; 165 struct cryptoini cria, crie; 166 int keylen; 167 int error; 168 169 txform = esp_algorithm_lookup(sav->alg_enc); 170 if (txform == NULL) { 171 DPRINTF(("%s: unsupported encryption algorithm %d\n", 172 __func__, sav->alg_enc)); 173 return EINVAL; 174 } 175 if (sav->key_enc == NULL) { 176 DPRINTF(("%s: no encoding key for %s algorithm\n", 177 __func__, txform->name)); 178 return EINVAL; 179 } 180 if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) { 181 DPRINTF(("%s: 4-byte IV not supported with protocol\n", 182 __func__)); 183 return EINVAL; 184 } 185 keylen = _KEYLEN(sav->key_enc); 186 if (txform->minkey > keylen || keylen > txform->maxkey) { 187 DPRINTF(("%s: invalid key length %u, must be in the range " 188 "[%u..%u] for algorithm %s\n", __func__, 189 keylen, txform->minkey, txform->maxkey, 190 txform->name)); 191 return EINVAL; 192 } 193 194 /* 195 * NB: The null xform needs a non-zero blocksize to keep the 196 * crypto code happy but if we use it to set ivlen then 197 * the ESP header will be processed incorrectly. The 198 * compromise is to force it to zero here. 199 */ 200 sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize); 201 sav->iv = (caddr_t) malloc(sav->ivlen, M_XDATA, M_WAITOK); 202 if (sav->iv == NULL) { 203 DPRINTF(("%s: no memory for IV\n", __func__)); 204 return EINVAL; 205 } 206 key_randomfill(sav->iv, sav->ivlen); /*XXX*/ 207 208 /* 209 * Setup AH-related state. 210 */ 211 if (sav->alg_auth != 0) { 212 error = ah_init0(sav, xsp, &cria); 213 if (error) 214 return error; 215 } 216 217 /* NB: override anything set in ah_init0 */ 218 sav->tdb_xform = xsp; 219 sav->tdb_encalgxform = txform; 220 221 /* Initialize crypto session. */ 222 bzero(&crie, sizeof (crie)); 223 crie.cri_alg = sav->tdb_encalgxform->type; 224 crie.cri_klen = _KEYBITS(sav->key_enc); 225 crie.cri_key = sav->key_enc->key_data; 226 /* XXX Rounds ? */ 227 228 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 229 /* init both auth & enc */ 230 crie.cri_next = &cria; 231 error = crypto_newsession(&sav->tdb_cryptoid, 232 &crie, V_crypto_support); 233 } else if (sav->tdb_encalgxform) { 234 error = crypto_newsession(&sav->tdb_cryptoid, 235 &crie, V_crypto_support); 236 } else if (sav->tdb_authalgxform) { 237 error = crypto_newsession(&sav->tdb_cryptoid, 238 &cria, V_crypto_support); 239 } else { 240 /* XXX cannot happen? */ 241 DPRINTF(("%s: no encoding OR authentication xform!\n", 242 __func__)); 243 error = EINVAL; 244 } 245 return error; 246} 247 248/* 249 * Paranoia. 250 */ 251static int 252esp_zeroize(struct secasvar *sav) 253{ 254 /* NB: ah_zerorize free's the crypto session state */ 255 int error = ah_zeroize(sav); 256 257 if (sav->key_enc) 258 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc)); 259 if (sav->iv) { 260 free(sav->iv, M_XDATA); 261 sav->iv = NULL; 262 } 263 sav->tdb_encalgxform = NULL; 264 sav->tdb_xform = NULL; 265 return error; 266} 267 268/* 269 * ESP input processing, called (eventually) through the protocol switch. 270 */ 271static int 272esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 273{ 274 INIT_VNET_IPSEC(curvnet); 275 struct auth_hash *esph; 276 struct enc_xform *espx; 277 struct tdb_ident *tdbi; 278 struct tdb_crypto *tc; 279 int plen, alen, hlen; 280 struct m_tag *mtag; 281 struct newesp *esp; 282 283 struct cryptodesc *crde; 284 struct cryptop *crp; 285 286 IPSEC_ASSERT(sav != NULL, ("null SA")); 287 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); 288 IPSEC_ASSERT((skip&3) == 0 && (m->m_pkthdr.len&3) == 0, 289 ("misaligned packet, skip %u pkt len %u", 290 skip, m->m_pkthdr.len)); 291 292 /* XXX don't pullup, just copy header */ 293 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 294 295 esph = sav->tdb_authalgxform; 296 espx = sav->tdb_encalgxform; 297 298 /* Determine the ESP header length */ 299 if (sav->flags & SADB_X_EXT_OLD) 300 hlen = sizeof (struct esp) + sav->ivlen; 301 else 302 hlen = sizeof (struct newesp) + sav->ivlen; 303 /* Authenticator hash size */ 304 alen = esph ? AH_HMAC_HASHLEN : 0; 305 306 /* 307 * Verify payload length is multiple of encryption algorithm 308 * block size. 309 * 310 * NB: This works for the null algorithm because the blocksize 311 * is 4 and all packets must be 4-byte aligned regardless 312 * of the algorithm. 313 */ 314 plen = m->m_pkthdr.len - (skip + hlen + alen); 315 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 316 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 317 " SA %s/%08lx\n", __func__, 318 plen, espx->blocksize, 319 ipsec_address(&sav->sah->saidx.dst), 320 (u_long) ntohl(sav->spi))); 321 V_espstat.esps_badilen++; 322 m_freem(m); 323 return EINVAL; 324 } 325 326 /* 327 * Check sequence number. 328 */ 329 if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) { 330 DPRINTF(("%s: packet replay check for %s\n", __func__, 331 ipsec_logsastr(sav))); /*XXX*/ 332 V_espstat.esps_replay++; 333 m_freem(m); 334 return ENOBUFS; /*XXX*/ 335 } 336 337 /* Update the counters */ 338 V_espstat.esps_ibytes += m->m_pkthdr.len - (skip + hlen + alen); 339 340 /* Find out if we've already done crypto */ 341 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL); 342 mtag != NULL; 343 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) { 344 tdbi = (struct tdb_ident *) (mtag + 1); 345 if (tdbi->proto == sav->sah->saidx.proto && 346 tdbi->spi == sav->spi && 347 !bcmp(&tdbi->dst, &sav->sah->saidx.dst, 348 sizeof(union sockaddr_union))) 349 break; 350 } 351 352 /* Get crypto descriptors */ 353 crp = crypto_getreq(esph && espx ? 2 : 1); 354 if (crp == NULL) { 355 DPRINTF(("%s: failed to acquire crypto descriptors\n", 356 __func__)); 357 V_espstat.esps_crypto++; 358 m_freem(m); 359 return ENOBUFS; 360 } 361 362 /* Get IPsec-specific opaque pointer */ 363 if (esph == NULL || mtag != NULL) 364 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 365 M_XDATA, M_NOWAIT|M_ZERO); 366 else 367 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen, 368 M_XDATA, M_NOWAIT|M_ZERO); 369 if (tc == NULL) { 370 crypto_freereq(crp); 371 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 372 V_espstat.esps_crypto++; 373 m_freem(m); 374 return ENOBUFS; 375 } 376 377 tc->tc_ptr = (caddr_t) mtag; 378 379 if (esph) { 380 struct cryptodesc *crda = crp->crp_desc; 381 382 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor")); 383 384 /* Authentication descriptor */ 385 crda->crd_skip = skip; 386 crda->crd_len = m->m_pkthdr.len - (skip + alen); 387 crda->crd_inject = m->m_pkthdr.len - alen; 388 389 crda->crd_alg = esph->type; 390 crda->crd_key = sav->key_auth->key_data; 391 crda->crd_klen = _KEYBITS(sav->key_auth); 392 393 /* Copy the authenticator */ 394 if (mtag == NULL) 395 m_copydata(m, m->m_pkthdr.len - alen, alen, 396 (caddr_t) (tc + 1)); 397 398 /* Chain authentication request */ 399 crde = crda->crd_next; 400 } else { 401 crde = crp->crp_desc; 402 } 403 404 /* Crypto operation descriptor */ 405 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 406 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 407 crp->crp_buf = (caddr_t) m; 408 crp->crp_callback = esp_input_cb; 409 crp->crp_sid = sav->tdb_cryptoid; 410 crp->crp_opaque = (caddr_t) tc; 411 412 /* These are passed as-is to the callback */ 413 tc->tc_spi = sav->spi; 414 tc->tc_dst = sav->sah->saidx.dst; 415 tc->tc_proto = sav->sah->saidx.proto; 416 tc->tc_protoff = protoff; 417 tc->tc_skip = skip; 418 419 /* Decryption descriptor */ 420 if (espx) { 421 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor")); 422 crde->crd_skip = skip + hlen; 423 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 424 crde->crd_inject = skip + hlen - sav->ivlen; 425 426 crde->crd_alg = espx->type; 427 crde->crd_key = sav->key_enc->key_data; 428 crde->crd_klen = _KEYBITS(sav->key_enc); 429 /* XXX Rounds ? */ 430 } 431 432 if (mtag == NULL) 433 return crypto_dispatch(crp); 434 else 435 return esp_input_cb(crp); 436} 437 438#ifdef INET6 439#define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \ 440 if (saidx->dst.sa.sa_family == AF_INET6) { \ 441 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \ 442 } else { \ 443 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \ 444 } \ 445} while (0) 446#else 447#define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \ 448 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag)) 449#endif 450 451/* 452 * ESP input callback from the crypto driver. 453 */ 454static int 455esp_input_cb(struct cryptop *crp) 456{ 457 INIT_VNET_IPSEC(curvnet); 458 u_int8_t lastthree[3], aalg[AH_HMAC_HASHLEN]; 459 int hlen, skip, protoff, error; 460 struct mbuf *m; 461 struct cryptodesc *crd; 462 struct auth_hash *esph; 463 struct enc_xform *espx; 464 struct tdb_crypto *tc; 465 struct m_tag *mtag; 466 struct secasvar *sav; 467 struct secasindex *saidx; 468 caddr_t ptr; 469 470 crd = crp->crp_desc; 471 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!")); 472 473 tc = (struct tdb_crypto *) crp->crp_opaque; 474 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!")); 475 skip = tc->tc_skip; 476 protoff = tc->tc_protoff; 477 mtag = (struct m_tag *) tc->tc_ptr; 478 m = (struct mbuf *) crp->crp_buf; 479 480 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 481 if (sav == NULL) { 482 V_espstat.esps_notdb++; 483 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 484 __func__, ipsec_address(&tc->tc_dst), 485 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 486 error = ENOBUFS; /*XXX*/ 487 goto bad; 488 } 489 490 saidx = &sav->sah->saidx; 491 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 492 saidx->dst.sa.sa_family == AF_INET6, 493 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 494 495 esph = sav->tdb_authalgxform; 496 espx = sav->tdb_encalgxform; 497 498 /* Check for crypto errors */ 499 if (crp->crp_etype) { 500 /* Reset the session ID */ 501 if (sav->tdb_cryptoid != 0) 502 sav->tdb_cryptoid = crp->crp_sid; 503 504 if (crp->crp_etype == EAGAIN) { 505 KEY_FREESAV(&sav); 506 error = crypto_dispatch(crp); 507 return error; 508 } 509 510 V_espstat.esps_noxform++; 511 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 512 error = crp->crp_etype; 513 goto bad; 514 } 515 516 /* Shouldn't happen... */ 517 if (m == NULL) { 518 V_espstat.esps_crypto++; 519 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 520 error = EINVAL; 521 goto bad; 522 } 523 V_espstat.esps_hist[sav->alg_enc]++; 524 525 /* If authentication was performed, check now. */ 526 if (esph != NULL) { 527 /* 528 * If we have a tag, it means an IPsec-aware NIC did 529 * the verification for us. Otherwise we need to 530 * check the authentication calculation. 531 */ 532 V_ahstat.ahs_hist[sav->alg_auth]++; 533 if (mtag == NULL) { 534 /* Copy the authenticator from the packet */ 535 m_copydata(m, m->m_pkthdr.len - AH_HMAC_HASHLEN, 536 AH_HMAC_HASHLEN, aalg); 537 538 ptr = (caddr_t) (tc + 1); 539 540 /* Verify authenticator */ 541 if (bcmp(ptr, aalg, AH_HMAC_HASHLEN) != 0) { 542 DPRINTF(("%s: " 543 "authentication hash mismatch for packet in SA %s/%08lx\n", 544 __func__, 545 ipsec_address(&saidx->dst), 546 (u_long) ntohl(sav->spi))); 547 V_espstat.esps_badauth++; 548 error = EACCES; 549 goto bad; 550 } 551 } 552 553 /* Remove trailing authenticator */ 554 m_adj(m, -AH_HMAC_HASHLEN); 555 } 556 557 /* Release the crypto descriptors */ 558 free(tc, M_XDATA), tc = NULL; 559 crypto_freereq(crp), crp = NULL; 560 561 /* 562 * Packet is now decrypted. 563 */ 564 m->m_flags |= M_DECRYPTED; 565 566 /* 567 * Update replay sequence number, if appropriate. 568 */ 569 if (sav->replay) { 570 u_int32_t seq; 571 572 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 573 sizeof (seq), (caddr_t) &seq); 574 if (ipsec_updatereplay(ntohl(seq), sav)) { 575 DPRINTF(("%s: packet replay check for %s\n", __func__, 576 ipsec_logsastr(sav))); 577 V_espstat.esps_replay++; 578 error = ENOBUFS; 579 goto bad; 580 } 581 } 582 583 /* Determine the ESP header length */ 584 if (sav->flags & SADB_X_EXT_OLD) 585 hlen = sizeof (struct esp) + sav->ivlen; 586 else 587 hlen = sizeof (struct newesp) + sav->ivlen; 588 589 /* Remove the ESP header and IV from the mbuf. */ 590 error = m_striphdr(m, skip, hlen); 591 if (error) { 592 V_espstat.esps_hdrops++; 593 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 594 ipsec_address(&sav->sah->saidx.dst), 595 (u_long) ntohl(sav->spi))); 596 goto bad; 597 } 598 599 /* Save the last three bytes of decrypted data */ 600 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 601 602 /* Verify pad length */ 603 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 604 V_espstat.esps_badilen++; 605 DPRINTF(("%s: invalid padding length %d for %u byte packet " 606 "in SA %s/%08lx\n", __func__, 607 lastthree[1], m->m_pkthdr.len - skip, 608 ipsec_address(&sav->sah->saidx.dst), 609 (u_long) ntohl(sav->spi))); 610 error = EINVAL; 611 goto bad; 612 } 613 614 /* Verify correct decryption by checking the last padding bytes */ 615 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 616 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 617 V_espstat.esps_badenc++; 618 DPRINTF(("%s: decryption failed for packet in " 619 "SA %s/%08lx\n", __func__, 620 ipsec_address(&sav->sah->saidx.dst), 621 (u_long) ntohl(sav->spi))); 622 error = EINVAL; 623 goto bad; 624 } 625 } 626 627 /* Trim the mbuf chain to remove trailing authenticator and padding */ 628 m_adj(m, -(lastthree[1] + 2)); 629 630 /* Restore the Next Protocol field */ 631 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 632 633 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag); 634 635 KEY_FREESAV(&sav); 636 return error; 637bad: 638 if (sav) 639 KEY_FREESAV(&sav); 640 if (m != NULL) 641 m_freem(m); 642 if (tc != NULL) 643 free(tc, M_XDATA); 644 if (crp != NULL) 645 crypto_freereq(crp); 646 return error; 647} 648 649/* 650 * ESP output routine, called by ipsec[46]_process_packet(). 651 */ 652static int 653esp_output( 654 struct mbuf *m, 655 struct ipsecrequest *isr, 656 struct mbuf **mp, 657 int skip, 658 int protoff 659) 660{ 661 INIT_VNET_IPSEC(curvnet); 662 struct enc_xform *espx; 663 struct auth_hash *esph; 664 int hlen, rlen, plen, padding, blks, alen, i, roff; 665 struct mbuf *mo = (struct mbuf *) NULL; 666 struct tdb_crypto *tc; 667 struct secasvar *sav; 668 struct secasindex *saidx; 669 unsigned char *pad; 670 u_int8_t prot; 671 int error, maxpacketsize; 672 673 struct cryptodesc *crde = NULL, *crda = NULL; 674 struct cryptop *crp; 675 676 sav = isr->sav; 677 IPSEC_ASSERT(sav != NULL, ("null SA")); 678 esph = sav->tdb_authalgxform; 679 espx = sav->tdb_encalgxform; 680 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 681 682 if (sav->flags & SADB_X_EXT_OLD) 683 hlen = sizeof (struct esp) + sav->ivlen; 684 else 685 hlen = sizeof (struct newesp) + sav->ivlen; 686 687 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 688 /* 689 * NB: The null encoding transform has a blocksize of 4 690 * so that headers are properly aligned. 691 */ 692 blks = espx->blocksize; /* IV blocksize */ 693 694 /* XXX clamp padding length a la KAME??? */ 695 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 696 plen = rlen + padding; /* Padded payload length. */ 697 698 if (esph) 699 alen = AH_HMAC_HASHLEN; 700 else 701 alen = 0; 702 703 V_espstat.esps_output++; 704 705 saidx = &sav->sah->saidx; 706 /* Check for maximum packet size violations. */ 707 switch (saidx->dst.sa.sa_family) { 708#ifdef INET 709 case AF_INET: 710 maxpacketsize = IP_MAXPACKET; 711 break; 712#endif /* INET */ 713#ifdef INET6 714 case AF_INET6: 715 maxpacketsize = IPV6_MAXPACKET; 716 break; 717#endif /* INET6 */ 718 default: 719 DPRINTF(("%s: unknown/unsupported protocol " 720 "family %d, SA %s/%08lx\n", __func__, 721 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst), 722 (u_long) ntohl(sav->spi))); 723 V_espstat.esps_nopf++; 724 error = EPFNOSUPPORT; 725 goto bad; 726 } 727 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 728 DPRINTF(("%s: packet in SA %s/%08lx got too big " 729 "(len %u, max len %u)\n", __func__, 730 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi), 731 skip + hlen + rlen + padding + alen, maxpacketsize)); 732 V_espstat.esps_toobig++; 733 error = EMSGSIZE; 734 goto bad; 735 } 736 737 /* Update the counters. */ 738 V_espstat.esps_obytes += m->m_pkthdr.len - skip; 739 740 m = m_unshare(m, M_NOWAIT); 741 if (m == NULL) { 742 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 743 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 744 V_espstat.esps_hdrops++; 745 error = ENOBUFS; 746 goto bad; 747 } 748 749 /* Inject ESP header. */ 750 mo = m_makespace(m, skip, hlen, &roff); 751 if (mo == NULL) { 752 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 753 __func__, hlen, ipsec_address(&saidx->dst), 754 (u_long) ntohl(sav->spi))); 755 V_espstat.esps_hdrops++; /* XXX diffs from openbsd */ 756 error = ENOBUFS; 757 goto bad; 758 } 759 760 /* Initialize ESP header. */ 761 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t)); 762 if (sav->replay) { 763 u_int32_t replay; 764 765#ifdef REGRESSION 766 /* Emulate replay attack when ipsec_replay is TRUE. */ 767 if (!V_ipsec_replay) 768#endif 769 sav->replay->count++; 770 replay = htonl(sav->replay->count); 771 bcopy((caddr_t) &replay, 772 mtod(mo, caddr_t) + roff + sizeof(u_int32_t), 773 sizeof(u_int32_t)); 774 } 775 776 /* 777 * Add padding -- better to do it ourselves than use the crypto engine, 778 * although if/when we support compression, we'd have to do that. 779 */ 780 pad = (u_char *) m_pad(m, padding + alen); 781 if (pad == NULL) { 782 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 783 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 784 m = NULL; /* NB: free'd by m_pad */ 785 error = ENOBUFS; 786 goto bad; 787 } 788 789 /* 790 * Add padding: random, zero, or self-describing. 791 * XXX catch unexpected setting 792 */ 793 switch (sav->flags & SADB_X_EXT_PMASK) { 794 case SADB_X_EXT_PRAND: 795 (void) read_random(pad, padding - 2); 796 break; 797 case SADB_X_EXT_PZERO: 798 bzero(pad, padding - 2); 799 break; 800 case SADB_X_EXT_PSEQ: 801 for (i = 0; i < padding - 2; i++) 802 pad[i] = i+1; 803 break; 804 } 805 806 /* Fix padding length and Next Protocol in padding itself. */ 807 pad[padding - 2] = padding - 2; 808 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 809 810 /* Fix Next Protocol in IPv4/IPv6 header. */ 811 prot = IPPROTO_ESP; 812 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 813 814 /* Get crypto descriptors. */ 815 crp = crypto_getreq(esph && espx ? 2 : 1); 816 if (crp == NULL) { 817 DPRINTF(("%s: failed to acquire crypto descriptors\n", 818 __func__)); 819 V_espstat.esps_crypto++; 820 error = ENOBUFS; 821 goto bad; 822 } 823 824 if (espx) { 825 crde = crp->crp_desc; 826 crda = crde->crd_next; 827 828 /* Encryption descriptor. */ 829 crde->crd_skip = skip + hlen; 830 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 831 crde->crd_flags = CRD_F_ENCRYPT; 832 crde->crd_inject = skip + hlen - sav->ivlen; 833 834 /* Encryption operation. */ 835 crde->crd_alg = espx->type; 836 crde->crd_key = sav->key_enc->key_data; 837 crde->crd_klen = _KEYBITS(sav->key_enc); 838 /* XXX Rounds ? */ 839 } else 840 crda = crp->crp_desc; 841 842 /* IPsec-specific opaque crypto info. */ 843 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 844 M_XDATA, M_NOWAIT|M_ZERO); 845 if (tc == NULL) { 846 crypto_freereq(crp); 847 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 848 V_espstat.esps_crypto++; 849 error = ENOBUFS; 850 goto bad; 851 } 852 853 /* Callback parameters */ 854 tc->tc_isr = isr; 855 tc->tc_spi = sav->spi; 856 tc->tc_dst = saidx->dst; 857 tc->tc_proto = saidx->proto; 858 859 /* Crypto operation descriptor. */ 860 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 861 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 862 crp->crp_buf = (caddr_t) m; 863 crp->crp_callback = esp_output_cb; 864 crp->crp_opaque = (caddr_t) tc; 865 crp->crp_sid = sav->tdb_cryptoid; 866 867 if (esph) { 868 /* Authentication descriptor. */ 869 crda->crd_skip = skip; 870 crda->crd_len = m->m_pkthdr.len - (skip + alen); 871 crda->crd_inject = m->m_pkthdr.len - alen; 872 873 /* Authentication operation. */ 874 crda->crd_alg = esph->type; 875 crda->crd_key = sav->key_auth->key_data; 876 crda->crd_klen = _KEYBITS(sav->key_auth); 877 } 878 879 return crypto_dispatch(crp); 880bad: 881 if (m) 882 m_freem(m); 883 return (error); 884} 885 886/* 887 * ESP output callback from the crypto driver. 888 */ 889static int 890esp_output_cb(struct cryptop *crp) 891{ 892 INIT_VNET_IPSEC(curvnet); 893 struct tdb_crypto *tc; 894 struct ipsecrequest *isr; 895 struct secasvar *sav; 896 struct mbuf *m; 897 int err, error; 898 899 tc = (struct tdb_crypto *) crp->crp_opaque; 900 IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); 901 m = (struct mbuf *) crp->crp_buf; 902 903 isr = tc->tc_isr; 904 IPSECREQUEST_LOCK(isr); 905 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 906 if (sav == NULL) { 907 V_espstat.esps_notdb++; 908 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 909 __func__, ipsec_address(&tc->tc_dst), 910 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 911 error = ENOBUFS; /*XXX*/ 912 goto bad; 913 } 914 IPSEC_ASSERT(isr->sav == sav, 915 ("SA changed was %p now %p\n", isr->sav, sav)); 916 917 /* Check for crypto errors. */ 918 if (crp->crp_etype) { 919 /* Reset session ID. */ 920 if (sav->tdb_cryptoid != 0) 921 sav->tdb_cryptoid = crp->crp_sid; 922 923 if (crp->crp_etype == EAGAIN) { 924 KEY_FREESAV(&sav); 925 IPSECREQUEST_UNLOCK(isr); 926 error = crypto_dispatch(crp); 927 return error; 928 } 929 930 V_espstat.esps_noxform++; 931 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 932 error = crp->crp_etype; 933 goto bad; 934 } 935 936 /* Shouldn't happen... */ 937 if (m == NULL) { 938 V_espstat.esps_crypto++; 939 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 940 error = EINVAL; 941 goto bad; 942 } 943 V_espstat.esps_hist[sav->alg_enc]++; 944 if (sav->tdb_authalgxform != NULL) 945 V_ahstat.ahs_hist[sav->alg_auth]++; 946 947 /* Release crypto descriptors. */ 948 free(tc, M_XDATA); 949 crypto_freereq(crp); 950 951#ifdef REGRESSION 952 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 953 if (V_ipsec_integrity) { 954 static unsigned char ipseczeroes[AH_HMAC_HASHLEN]; 955 struct auth_hash *esph; 956 957 /* 958 * Corrupt HMAC if we want to test integrity verification of 959 * the other side. 960 */ 961 esph = sav->tdb_authalgxform; 962 if (esph != NULL) { 963 m_copyback(m, m->m_pkthdr.len - AH_HMAC_HASHLEN, 964 AH_HMAC_HASHLEN, ipseczeroes); 965 } 966 } 967#endif 968 969 /* NB: m is reclaimed by ipsec_process_done. */ 970 err = ipsec_process_done(m, isr); 971 KEY_FREESAV(&sav); 972 IPSECREQUEST_UNLOCK(isr); 973 return err; 974bad: 975 if (sav) 976 KEY_FREESAV(&sav); 977 IPSECREQUEST_UNLOCK(isr); 978 if (m) 979 m_freem(m); 980 free(tc, M_XDATA); 981 crypto_freereq(crp); 982 return error; 983} 984 985static struct xformsw esp_xformsw = { 986 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 987 esp_init, esp_zeroize, esp_input, 988 esp_output 989}; 990 991static void 992esp_attach(void) 993{ 994 995 xform_register(&esp_xformsw); 996 esp_iattach(NULL); 997} 998 999static int 1000esp_iattach(const void *unused __unused) 1001{ 1002 INIT_VNET_IPSEC(curvnet); 1003 1004#define MAXIV(xform) \ 1005 if (xform.blocksize > V_esp_max_ivlen) \ 1006 V_esp_max_ivlen = xform.blocksize \ 1007 1008 V_esp_enable = 1; 1009 V_esp_max_ivlen = 0; 1010 1011 MAXIV(enc_xform_des); /* SADB_EALG_DESCBC */ 1012 MAXIV(enc_xform_3des); /* SADB_EALG_3DESCBC */ 1013 MAXIV(enc_xform_rijndael128); /* SADB_X_EALG_AES */ 1014 MAXIV(enc_xform_blf); /* SADB_X_EALG_BLOWFISHCBC */ 1015 MAXIV(enc_xform_cast5); /* SADB_X_EALG_CAST128CBC */ 1016 MAXIV(enc_xform_skipjack); /* SADB_X_EALG_SKIPJACK */ 1017 MAXIV(enc_xform_null); /* SADB_EALG_NULL */ 1018 MAXIV(enc_xform_camellia); /* SADB_X_EALG_CAMELLIACBC */ 1019#undef MAXIV 1020 1021 return (0); 1022} 1023SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL); 1024