xform_esp.c revision 215701
1/* $FreeBSD: head/sys/netipsec/xform_esp.c 215701 2010-11-22 19:32:54Z dim $ */ 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#include <net/vnet.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 79VNET_DEFINE(int, esp_enable) = 1; 80VNET_DEFINE(struct espstat, espstat); 81 82SYSCTL_DECL(_net_inet_esp); 83SYSCTL_VNET_INT(_net_inet_esp, OID_AUTO, 84 esp_enable, CTLFLAG_RW, &VNET_NAME(esp_enable), 0, ""); 85SYSCTL_VNET_STRUCT(_net_inet_esp, IPSECCTL_STATS, 86 stats, CTLFLAG_RD, &VNET_NAME(espstat), espstat, ""); 87 88static VNET_DEFINE(int, esp_max_ivlen); /* max iv length over all algorithms */ 89#define V_esp_max_ivlen VNET(esp_max_ivlen) 90 91static int esp_input_cb(struct cryptop *op); 92static int esp_output_cb(struct cryptop *crp); 93 94/* 95 * NB: this is public for use by the PF_KEY support. 96 * NB: if you add support here; be sure to add code to esp_attach below! 97 */ 98struct enc_xform * 99esp_algorithm_lookup(int alg) 100{ 101 if (alg >= ESP_ALG_MAX) 102 return NULL; 103 switch (alg) { 104 case SADB_EALG_DESCBC: 105 return &enc_xform_des; 106 case SADB_EALG_3DESCBC: 107 return &enc_xform_3des; 108 case SADB_X_EALG_AES: 109 return &enc_xform_rijndael128; 110 case SADB_X_EALG_BLOWFISHCBC: 111 return &enc_xform_blf; 112 case SADB_X_EALG_CAST128CBC: 113 return &enc_xform_cast5; 114 case SADB_X_EALG_SKIPJACK: 115 return &enc_xform_skipjack; 116 case SADB_EALG_NULL: 117 return &enc_xform_null; 118 case SADB_X_EALG_CAMELLIACBC: 119 return &enc_xform_camellia; 120 } 121 return NULL; 122} 123 124size_t 125esp_hdrsiz(struct secasvar *sav) 126{ 127 size_t size; 128 129 if (sav != NULL) { 130 /*XXX not right for null algorithm--does it matter??*/ 131 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 132 ("SA with null xform")); 133 if (sav->flags & SADB_X_EXT_OLD) 134 size = sizeof (struct esp); 135 else 136 size = sizeof (struct newesp); 137 size += sav->tdb_encalgxform->blocksize + 9; 138 /*XXX need alg check???*/ 139 if (sav->tdb_authalgxform != NULL && sav->replay) 140 size += ah_hdrsiz(sav); 141 } else { 142 /* 143 * base header size 144 * + max iv length for CBC mode 145 * + max pad length 146 * + sizeof (pad length field) 147 * + sizeof (next header field) 148 * + max icv supported. 149 */ 150 size = sizeof (struct newesp) + V_esp_max_ivlen + 9 + 16; 151 } 152 return size; 153} 154 155/* 156 * esp_init() is called when an SPI is being set up. 157 */ 158static int 159esp_init(struct secasvar *sav, struct xformsw *xsp) 160{ 161 struct enc_xform *txform; 162 struct cryptoini cria, crie; 163 int keylen; 164 int error; 165 166 txform = esp_algorithm_lookup(sav->alg_enc); 167 if (txform == NULL) { 168 DPRINTF(("%s: unsupported encryption algorithm %d\n", 169 __func__, sav->alg_enc)); 170 return EINVAL; 171 } 172 if (sav->key_enc == NULL) { 173 DPRINTF(("%s: no encoding key for %s algorithm\n", 174 __func__, txform->name)); 175 return EINVAL; 176 } 177 if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) { 178 DPRINTF(("%s: 4-byte IV not supported with protocol\n", 179 __func__)); 180 return EINVAL; 181 } 182 keylen = _KEYLEN(sav->key_enc); 183 if (txform->minkey > keylen || keylen > txform->maxkey) { 184 DPRINTF(("%s: invalid key length %u, must be in the range " 185 "[%u..%u] for algorithm %s\n", __func__, 186 keylen, txform->minkey, txform->maxkey, 187 txform->name)); 188 return EINVAL; 189 } 190 191 /* 192 * NB: The null xform needs a non-zero blocksize to keep the 193 * crypto code happy but if we use it to set ivlen then 194 * the ESP header will be processed incorrectly. The 195 * compromise is to force it to zero here. 196 */ 197 sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize); 198 sav->iv = (caddr_t) malloc(sav->ivlen, M_XDATA, M_WAITOK); 199 if (sav->iv == NULL) { 200 DPRINTF(("%s: no memory for IV\n", __func__)); 201 return EINVAL; 202 } 203 key_randomfill(sav->iv, sav->ivlen); /*XXX*/ 204 205 /* 206 * Setup AH-related state. 207 */ 208 if (sav->alg_auth != 0) { 209 error = ah_init0(sav, xsp, &cria); 210 if (error) 211 return error; 212 } 213 214 /* NB: override anything set in ah_init0 */ 215 sav->tdb_xform = xsp; 216 sav->tdb_encalgxform = txform; 217 218 /* Initialize crypto session. */ 219 bzero(&crie, sizeof (crie)); 220 crie.cri_alg = sav->tdb_encalgxform->type; 221 crie.cri_klen = _KEYBITS(sav->key_enc); 222 crie.cri_key = sav->key_enc->key_data; 223 /* XXX Rounds ? */ 224 225 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 226 /* init both auth & enc */ 227 crie.cri_next = &cria; 228 error = crypto_newsession(&sav->tdb_cryptoid, 229 &crie, V_crypto_support); 230 } else if (sav->tdb_encalgxform) { 231 error = crypto_newsession(&sav->tdb_cryptoid, 232 &crie, V_crypto_support); 233 } else if (sav->tdb_authalgxform) { 234 error = crypto_newsession(&sav->tdb_cryptoid, 235 &cria, V_crypto_support); 236 } else { 237 /* XXX cannot happen? */ 238 DPRINTF(("%s: no encoding OR authentication xform!\n", 239 __func__)); 240 error = EINVAL; 241 } 242 return error; 243} 244 245/* 246 * Paranoia. 247 */ 248static int 249esp_zeroize(struct secasvar *sav) 250{ 251 /* NB: ah_zerorize free's the crypto session state */ 252 int error = ah_zeroize(sav); 253 254 if (sav->key_enc) 255 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc)); 256 if (sav->iv) { 257 free(sav->iv, M_XDATA); 258 sav->iv = NULL; 259 } 260 sav->tdb_encalgxform = NULL; 261 sav->tdb_xform = NULL; 262 return error; 263} 264 265/* 266 * ESP input processing, called (eventually) through the protocol switch. 267 */ 268static int 269esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 270{ 271 struct auth_hash *esph; 272 struct enc_xform *espx; 273 struct tdb_ident *tdbi; 274 struct tdb_crypto *tc; 275 int plen, alen, hlen; 276 struct m_tag *mtag; 277 struct newesp *esp; 278 279 struct cryptodesc *crde; 280 struct cryptop *crp; 281 282 IPSEC_ASSERT(sav != NULL, ("null SA")); 283 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); 284 285 /* Valid IP Packet length ? */ 286 if ( (skip&3) || (m->m_pkthdr.len&3) ){ 287 DPRINTF(("%s: misaligned packet, skip %u pkt len %u", 288 __func__, skip, m->m_pkthdr.len)); 289 V_espstat.esps_badilen++; 290 m_freem(m); 291 return EINVAL; 292 } 293 294 /* XXX don't pullup, just copy header */ 295 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 296 297 esph = sav->tdb_authalgxform; 298 espx = sav->tdb_encalgxform; 299 300 /* Determine the ESP header length */ 301 if (sav->flags & SADB_X_EXT_OLD) 302 hlen = sizeof (struct esp) + sav->ivlen; 303 else 304 hlen = sizeof (struct newesp) + sav->ivlen; 305 /* Authenticator hash size */ 306 alen = esph ? AH_HMAC_HASHLEN : 0; 307 308 /* 309 * Verify payload length is multiple of encryption algorithm 310 * block size. 311 * 312 * NB: This works for the null algorithm because the blocksize 313 * is 4 and all packets must be 4-byte aligned regardless 314 * of the algorithm. 315 */ 316 plen = m->m_pkthdr.len - (skip + hlen + alen); 317 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 318 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 319 " SA %s/%08lx\n", __func__, 320 plen, espx->blocksize, 321 ipsec_address(&sav->sah->saidx.dst), 322 (u_long) ntohl(sav->spi))); 323 V_espstat.esps_badilen++; 324 m_freem(m); 325 return EINVAL; 326 } 327 328 /* 329 * Check sequence number. 330 */ 331 if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) { 332 DPRINTF(("%s: packet replay check for %s\n", __func__, 333 ipsec_logsastr(sav))); /*XXX*/ 334 V_espstat.esps_replay++; 335 m_freem(m); 336 return ENOBUFS; /*XXX*/ 337 } 338 339 /* Update the counters */ 340 V_espstat.esps_ibytes += m->m_pkthdr.len - (skip + hlen + alen); 341 342 /* Find out if we've already done crypto */ 343 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL); 344 mtag != NULL; 345 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) { 346 tdbi = (struct tdb_ident *) (mtag + 1); 347 if (tdbi->proto == sav->sah->saidx.proto && 348 tdbi->spi == sav->spi && 349 !bcmp(&tdbi->dst, &sav->sah->saidx.dst, 350 sizeof(union sockaddr_union))) 351 break; 352 } 353 354 /* Get crypto descriptors */ 355 crp = crypto_getreq(esph && espx ? 2 : 1); 356 if (crp == NULL) { 357 DPRINTF(("%s: failed to acquire crypto descriptors\n", 358 __func__)); 359 V_espstat.esps_crypto++; 360 m_freem(m); 361 return ENOBUFS; 362 } 363 364 /* Get IPsec-specific opaque pointer */ 365 if (esph == NULL || mtag != NULL) 366 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 367 M_XDATA, M_NOWAIT|M_ZERO); 368 else 369 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen, 370 M_XDATA, M_NOWAIT|M_ZERO); 371 if (tc == NULL) { 372 crypto_freereq(crp); 373 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 374 V_espstat.esps_crypto++; 375 m_freem(m); 376 return ENOBUFS; 377 } 378 379 tc->tc_ptr = (caddr_t) mtag; 380 381 if (esph) { 382 struct cryptodesc *crda = crp->crp_desc; 383 384 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor")); 385 386 /* Authentication descriptor */ 387 crda->crd_skip = skip; 388 crda->crd_len = m->m_pkthdr.len - (skip + alen); 389 crda->crd_inject = m->m_pkthdr.len - alen; 390 391 crda->crd_alg = esph->type; 392 crda->crd_key = sav->key_auth->key_data; 393 crda->crd_klen = _KEYBITS(sav->key_auth); 394 395 /* Copy the authenticator */ 396 if (mtag == NULL) 397 m_copydata(m, m->m_pkthdr.len - alen, alen, 398 (caddr_t) (tc + 1)); 399 400 /* Chain authentication request */ 401 crde = crda->crd_next; 402 } else { 403 crde = crp->crp_desc; 404 } 405 406 /* Crypto operation descriptor */ 407 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 408 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 409 crp->crp_buf = (caddr_t) m; 410 crp->crp_callback = esp_input_cb; 411 crp->crp_sid = sav->tdb_cryptoid; 412 crp->crp_opaque = (caddr_t) tc; 413 414 /* These are passed as-is to the callback */ 415 tc->tc_spi = sav->spi; 416 tc->tc_dst = sav->sah->saidx.dst; 417 tc->tc_proto = sav->sah->saidx.proto; 418 tc->tc_protoff = protoff; 419 tc->tc_skip = skip; 420 421 /* Decryption descriptor */ 422 if (espx) { 423 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor")); 424 crde->crd_skip = skip + hlen; 425 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 426 crde->crd_inject = skip + hlen - sav->ivlen; 427 428 crde->crd_alg = espx->type; 429 crde->crd_key = sav->key_enc->key_data; 430 crde->crd_klen = _KEYBITS(sav->key_enc); 431 /* XXX Rounds ? */ 432 } 433 434 if (mtag == NULL) 435 return crypto_dispatch(crp); 436 else 437 return esp_input_cb(crp); 438} 439 440#ifdef INET6 441#define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \ 442 if (saidx->dst.sa.sa_family == AF_INET6) { \ 443 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \ 444 } else { \ 445 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \ 446 } \ 447} while (0) 448#else 449#define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \ 450 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag)) 451#endif 452 453/* 454 * ESP input callback from the crypto driver. 455 */ 456static int 457esp_input_cb(struct cryptop *crp) 458{ 459 u_int8_t lastthree[3], aalg[AH_HMAC_HASHLEN]; 460 int hlen, skip, protoff, error; 461 struct mbuf *m; 462 struct cryptodesc *crd; 463 struct auth_hash *esph; 464 struct enc_xform *espx; 465 struct tdb_crypto *tc; 466 struct m_tag *mtag; 467 struct secasvar *sav; 468 struct secasindex *saidx; 469 caddr_t ptr; 470 471 crd = crp->crp_desc; 472 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!")); 473 474 tc = (struct tdb_crypto *) crp->crp_opaque; 475 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!")); 476 skip = tc->tc_skip; 477 protoff = tc->tc_protoff; 478 mtag = (struct m_tag *) tc->tc_ptr; 479 m = (struct mbuf *) crp->crp_buf; 480 481 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 482 if (sav == NULL) { 483 V_espstat.esps_notdb++; 484 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 485 __func__, ipsec_address(&tc->tc_dst), 486 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 487 error = ENOBUFS; /*XXX*/ 488 goto bad; 489 } 490 491 saidx = &sav->sah->saidx; 492 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 493 saidx->dst.sa.sa_family == AF_INET6, 494 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 495 496 esph = sav->tdb_authalgxform; 497 espx = sav->tdb_encalgxform; 498 499 /* Check for crypto errors */ 500 if (crp->crp_etype) { 501 /* Reset the session ID */ 502 if (sav->tdb_cryptoid != 0) 503 sav->tdb_cryptoid = crp->crp_sid; 504 505 if (crp->crp_etype == EAGAIN) { 506 KEY_FREESAV(&sav); 507 error = crypto_dispatch(crp); 508 return error; 509 } 510 511 V_espstat.esps_noxform++; 512 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 513 error = crp->crp_etype; 514 goto bad; 515 } 516 517 /* Shouldn't happen... */ 518 if (m == NULL) { 519 V_espstat.esps_crypto++; 520 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 521 error = EINVAL; 522 goto bad; 523 } 524 V_espstat.esps_hist[sav->alg_enc]++; 525 526 /* If authentication was performed, check now. */ 527 if (esph != NULL) { 528 /* 529 * If we have a tag, it means an IPsec-aware NIC did 530 * the verification for us. Otherwise we need to 531 * check the authentication calculation. 532 */ 533 V_ahstat.ahs_hist[sav->alg_auth]++; 534 if (mtag == NULL) { 535 /* Copy the authenticator from the packet */ 536 m_copydata(m, m->m_pkthdr.len - AH_HMAC_HASHLEN, 537 AH_HMAC_HASHLEN, aalg); 538 539 ptr = (caddr_t) (tc + 1); 540 541 /* Verify authenticator */ 542 if (bcmp(ptr, aalg, AH_HMAC_HASHLEN) != 0) { 543 DPRINTF(("%s: " 544 "authentication hash mismatch for packet in SA %s/%08lx\n", 545 __func__, 546 ipsec_address(&saidx->dst), 547 (u_long) ntohl(sav->spi))); 548 V_espstat.esps_badauth++; 549 error = EACCES; 550 goto bad; 551 } 552 } 553 554 /* Remove trailing authenticator */ 555 m_adj(m, -AH_HMAC_HASHLEN); 556 } 557 558 /* Release the crypto descriptors */ 559 free(tc, M_XDATA), tc = NULL; 560 crypto_freereq(crp), crp = NULL; 561 562 /* 563 * Packet is now decrypted. 564 */ 565 m->m_flags |= M_DECRYPTED; 566 567 /* 568 * Update replay sequence number, if appropriate. 569 */ 570 if (sav->replay) { 571 u_int32_t seq; 572 573 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 574 sizeof (seq), (caddr_t) &seq); 575 if (ipsec_updatereplay(ntohl(seq), sav)) { 576 DPRINTF(("%s: packet replay check for %s\n", __func__, 577 ipsec_logsastr(sav))); 578 V_espstat.esps_replay++; 579 error = ENOBUFS; 580 goto bad; 581 } 582 } 583 584 /* Determine the ESP header length */ 585 if (sav->flags & SADB_X_EXT_OLD) 586 hlen = sizeof (struct esp) + sav->ivlen; 587 else 588 hlen = sizeof (struct newesp) + sav->ivlen; 589 590 /* Remove the ESP header and IV from the mbuf. */ 591 error = m_striphdr(m, skip, hlen); 592 if (error) { 593 V_espstat.esps_hdrops++; 594 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 595 ipsec_address(&sav->sah->saidx.dst), 596 (u_long) ntohl(sav->spi))); 597 goto bad; 598 } 599 600 /* Save the last three bytes of decrypted data */ 601 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 602 603 /* Verify pad length */ 604 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 605 V_espstat.esps_badilen++; 606 DPRINTF(("%s: invalid padding length %d for %u byte packet " 607 "in SA %s/%08lx\n", __func__, 608 lastthree[1], m->m_pkthdr.len - skip, 609 ipsec_address(&sav->sah->saidx.dst), 610 (u_long) ntohl(sav->spi))); 611 error = EINVAL; 612 goto bad; 613 } 614 615 /* Verify correct decryption by checking the last padding bytes */ 616 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 617 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 618 V_espstat.esps_badenc++; 619 DPRINTF(("%s: decryption failed for packet in " 620 "SA %s/%08lx\n", __func__, 621 ipsec_address(&sav->sah->saidx.dst), 622 (u_long) ntohl(sav->spi))); 623 error = EINVAL; 624 goto bad; 625 } 626 } 627 628 /* Trim the mbuf chain to remove trailing authenticator and padding */ 629 m_adj(m, -(lastthree[1] + 2)); 630 631 /* Restore the Next Protocol field */ 632 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 633 634 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag); 635 636 KEY_FREESAV(&sav); 637 return error; 638bad: 639 if (sav) 640 KEY_FREESAV(&sav); 641 if (m != NULL) 642 m_freem(m); 643 if (tc != NULL) 644 free(tc, M_XDATA); 645 if (crp != NULL) 646 crypto_freereq(crp); 647 return error; 648} 649 650/* 651 * ESP output routine, called by ipsec[46]_process_packet(). 652 */ 653static int 654esp_output( 655 struct mbuf *m, 656 struct ipsecrequest *isr, 657 struct mbuf **mp, 658 int skip, 659 int protoff 660) 661{ 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 struct tdb_crypto *tc; 893 struct ipsecrequest *isr; 894 struct secasvar *sav; 895 struct mbuf *m; 896 int err, error; 897 898 tc = (struct tdb_crypto *) crp->crp_opaque; 899 IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); 900 m = (struct mbuf *) crp->crp_buf; 901 902 isr = tc->tc_isr; 903 IPSECREQUEST_LOCK(isr); 904 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 905 if (sav == NULL) { 906 V_espstat.esps_notdb++; 907 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 908 __func__, ipsec_address(&tc->tc_dst), 909 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 910 error = ENOBUFS; /*XXX*/ 911 goto bad; 912 } 913 IPSEC_ASSERT(isr->sav == sav, 914 ("SA changed was %p now %p\n", isr->sav, sav)); 915 916 /* Check for crypto errors. */ 917 if (crp->crp_etype) { 918 /* Reset session ID. */ 919 if (sav->tdb_cryptoid != 0) 920 sav->tdb_cryptoid = crp->crp_sid; 921 922 if (crp->crp_etype == EAGAIN) { 923 KEY_FREESAV(&sav); 924 IPSECREQUEST_UNLOCK(isr); 925 error = crypto_dispatch(crp); 926 return error; 927 } 928 929 V_espstat.esps_noxform++; 930 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 931 error = crp->crp_etype; 932 goto bad; 933 } 934 935 /* Shouldn't happen... */ 936 if (m == NULL) { 937 V_espstat.esps_crypto++; 938 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 939 error = EINVAL; 940 goto bad; 941 } 942 V_espstat.esps_hist[sav->alg_enc]++; 943 if (sav->tdb_authalgxform != NULL) 944 V_ahstat.ahs_hist[sav->alg_auth]++; 945 946 /* Release crypto descriptors. */ 947 free(tc, M_XDATA); 948 crypto_freereq(crp); 949 950#ifdef REGRESSION 951 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 952 if (V_ipsec_integrity) { 953 static unsigned char ipseczeroes[AH_HMAC_HASHLEN]; 954 struct auth_hash *esph; 955 956 /* 957 * Corrupt HMAC if we want to test integrity verification of 958 * the other side. 959 */ 960 esph = sav->tdb_authalgxform; 961 if (esph != NULL) { 962 m_copyback(m, m->m_pkthdr.len - AH_HMAC_HASHLEN, 963 AH_HMAC_HASHLEN, ipseczeroes); 964 } 965 } 966#endif 967 968 /* NB: m is reclaimed by ipsec_process_done. */ 969 err = ipsec_process_done(m, isr); 970 KEY_FREESAV(&sav); 971 IPSECREQUEST_UNLOCK(isr); 972 return err; 973bad: 974 if (sav) 975 KEY_FREESAV(&sav); 976 IPSECREQUEST_UNLOCK(isr); 977 if (m) 978 m_freem(m); 979 free(tc, M_XDATA); 980 crypto_freereq(crp); 981 return error; 982} 983 984static struct xformsw esp_xformsw = { 985 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 986 esp_init, esp_zeroize, esp_input, 987 esp_output 988}; 989 990static void 991esp_attach(void) 992{ 993#define MAXIV(xform) \ 994 if (xform.blocksize > V_esp_max_ivlen) \ 995 V_esp_max_ivlen = xform.blocksize \ 996 997 MAXIV(enc_xform_des); /* SADB_EALG_DESCBC */ 998 MAXIV(enc_xform_3des); /* SADB_EALG_3DESCBC */ 999 MAXIV(enc_xform_rijndael128); /* SADB_X_EALG_AES */ 1000 MAXIV(enc_xform_blf); /* SADB_X_EALG_BLOWFISHCBC */ 1001 MAXIV(enc_xform_cast5); /* SADB_X_EALG_CAST128CBC */ 1002 MAXIV(enc_xform_skipjack); /* SADB_X_EALG_SKIPJACK */ 1003 MAXIV(enc_xform_null); /* SADB_EALG_NULL */ 1004 MAXIV(enc_xform_camellia); /* SADB_X_EALG_CAMELLIACBC */ 1005 1006 xform_register(&esp_xformsw); 1007#undef MAXIV 1008} 1009SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL); 1010