1/* $FreeBSD$ */ 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_PCPUSTAT_DEFINE(struct espstat, espstat); 81VNET_PCPUSTAT_SYSINIT(espstat); 82 83#ifdef VIMAGE 84VNET_PCPUSTAT_SYSUNINIT(espstat); 85#endif /* VIMAGE */ 86 87SYSCTL_DECL(_net_inet_esp); 88SYSCTL_VNET_INT(_net_inet_esp, OID_AUTO, 89 esp_enable, CTLFLAG_RW, &VNET_NAME(esp_enable), 0, ""); 90SYSCTL_VNET_PCPUSTAT(_net_inet_esp, IPSECCTL_STATS, stats, 91 struct espstat, espstat, 92 "ESP statistics (struct espstat, netipsec/esp_var.h"); 93 94static int esp_input_cb(struct cryptop *op); 95static int esp_output_cb(struct cryptop *crp); 96 97/* 98 * NB: this is public for use by the PF_KEY support. 99 * NB: if you add support here; be sure to add code to esp_attach below! 100 */ 101struct enc_xform * 102esp_algorithm_lookup(int alg) 103{ 104 if (alg >= ESP_ALG_MAX) 105 return NULL; 106 switch (alg) { 107 case SADB_EALG_DESCBC: 108 return &enc_xform_des; 109 case SADB_EALG_3DESCBC: 110 return &enc_xform_3des; 111 case SADB_X_EALG_AES: 112 return &enc_xform_rijndael128; 113 case SADB_X_EALG_BLOWFISHCBC: 114 return &enc_xform_blf; 115 case SADB_X_EALG_CAST128CBC: 116 return &enc_xform_cast5; 117 case SADB_X_EALG_SKIPJACK: 118 return &enc_xform_skipjack; 119 case SADB_EALG_NULL: 120 return &enc_xform_null; 121 case SADB_X_EALG_CAMELLIACBC: 122 return &enc_xform_camellia; 123 } 124 return NULL; 125} 126 127size_t 128esp_hdrsiz(struct secasvar *sav) 129{ 130 size_t size; 131 132 if (sav != NULL) { 133 /*XXX not right for null algorithm--does it matter??*/ 134 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 135 ("SA with null xform")); 136 if (sav->flags & SADB_X_EXT_OLD) 137 size = sizeof (struct esp); 138 else 139 size = sizeof (struct newesp); 140 size += sav->tdb_encalgxform->blocksize + 9; 141 /*XXX need alg check???*/ 142 if (sav->tdb_authalgxform != NULL && sav->replay) 143 size += ah_hdrsiz(sav); 144 } else { 145 /* 146 * base header size 147 * + max iv length for CBC mode 148 * + max pad length 149 * + sizeof (pad length field) 150 * + sizeof (next header field) 151 * + max icv supported. 152 */ 153 size = sizeof (struct newesp) + EALG_MAX_BLOCK_LEN + 9 + 16; 154 } 155 return size; 156} 157 158/* 159 * esp_init() is called when an SPI is being set up. 160 */ 161static int 162esp_init(struct secasvar *sav, struct xformsw *xsp) 163{ 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 key_randomfill(sav->iv, sav->ivlen); /*XXX*/ 203 204 /* 205 * Setup AH-related state. 206 */ 207 if (sav->alg_auth != 0) { 208 error = ah_init0(sav, xsp, &cria); 209 if (error) 210 return error; 211 } 212 213 /* NB: override anything set in ah_init0 */ 214 sav->tdb_xform = xsp; 215 sav->tdb_encalgxform = txform; 216 217 /* Initialize crypto session. */ 218 bzero(&crie, sizeof (crie)); 219 crie.cri_alg = sav->tdb_encalgxform->type; 220 crie.cri_klen = _KEYBITS(sav->key_enc); 221 crie.cri_key = sav->key_enc->key_data; 222 /* XXX Rounds ? */ 223 224 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 225 /* init both auth & enc */ 226 crie.cri_next = &cria; 227 error = crypto_newsession(&sav->tdb_cryptoid, 228 &crie, V_crypto_support); 229 } else if (sav->tdb_encalgxform) { 230 error = crypto_newsession(&sav->tdb_cryptoid, 231 &crie, V_crypto_support); 232 } else if (sav->tdb_authalgxform) { 233 error = crypto_newsession(&sav->tdb_cryptoid, 234 &cria, V_crypto_support); 235 } else { 236 /* XXX cannot happen? */ 237 DPRINTF(("%s: no encoding OR authentication xform!\n", 238 __func__)); 239 error = EINVAL; 240 } 241 return error; 242} 243 244/* 245 * Paranoia. 246 */ 247static int 248esp_zeroize(struct secasvar *sav) 249{ 250 /* NB: ah_zerorize free's the crypto session state */ 251 int error = ah_zeroize(sav); 252 253 if (sav->key_enc) 254 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc)); 255 if (sav->iv) { 256 free(sav->iv, M_XDATA); 257 sav->iv = NULL; 258 } 259 sav->tdb_encalgxform = NULL; 260 sav->tdb_xform = NULL; 261 return error; 262} 263 264/* 265 * ESP input processing, called (eventually) through the protocol switch. 266 */ 267static int 268esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 269{ 270 struct auth_hash *esph; 271 struct enc_xform *espx; 272 struct tdb_ident *tdbi; 273 struct tdb_crypto *tc; 274 int plen, alen, hlen; 275 struct m_tag *mtag; 276 struct newesp *esp; 277 278 struct cryptodesc *crde; 279 struct cryptop *crp; 280 281 IPSEC_ASSERT(sav != NULL, ("null SA")); 282 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); 283 284 /* Valid IP Packet length ? */ 285 if ( (skip&3) || (m->m_pkthdr.len&3) ){ 286 DPRINTF(("%s: misaligned packet, skip %u pkt len %u", 287 __func__, skip, m->m_pkthdr.len)); 288 ESPSTAT_INC(esps_badilen); 289 m_freem(m); 290 return EINVAL; 291 } 292 293 /* XXX don't pullup, just copy header */ 294 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 295 296 esph = sav->tdb_authalgxform; 297 espx = sav->tdb_encalgxform; 298 299 /* Determine the ESP header length */ 300 if (sav->flags & SADB_X_EXT_OLD) 301 hlen = sizeof (struct esp) + sav->ivlen; 302 else 303 hlen = sizeof (struct newesp) + sav->ivlen; 304 /* Authenticator hash size */ 305 if (esph != NULL) { 306 switch (esph->type) { 307 case CRYPTO_SHA2_256_HMAC: 308 case CRYPTO_SHA2_384_HMAC: 309 case CRYPTO_SHA2_512_HMAC: 310 alen = esph->hashsize/2; 311 break; 312 default: 313 alen = AH_HMAC_HASHLEN; 314 break; 315 } 316 }else 317 alen = 0; 318 319 /* 320 * Verify payload length is multiple of encryption algorithm 321 * block size. 322 * 323 * NB: This works for the null algorithm because the blocksize 324 * is 4 and all packets must be 4-byte aligned regardless 325 * of the algorithm. 326 */ 327 plen = m->m_pkthdr.len - (skip + hlen + alen); 328 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 329 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 330 " SA %s/%08lx\n", __func__, 331 plen, espx->blocksize, 332 ipsec_address(&sav->sah->saidx.dst), 333 (u_long) ntohl(sav->spi))); 334 ESPSTAT_INC(esps_badilen); 335 m_freem(m); 336 return EINVAL; 337 } 338 339 /* 340 * Check sequence number. 341 */ 342 if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) { 343 DPRINTF(("%s: packet replay check for %s\n", __func__, 344 ipsec_logsastr(sav))); /*XXX*/ 345 ESPSTAT_INC(esps_replay); 346 m_freem(m); 347 return ENOBUFS; /*XXX*/ 348 } 349 350 /* Update the counters */ 351 ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen)); 352 353 /* Find out if we've already done crypto */ 354 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL); 355 mtag != NULL; 356 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) { 357 tdbi = (struct tdb_ident *) (mtag + 1); 358 if (tdbi->proto == sav->sah->saidx.proto && 359 tdbi->spi == sav->spi && 360 !bcmp(&tdbi->dst, &sav->sah->saidx.dst, 361 sizeof(union sockaddr_union))) 362 break; 363 } 364 365 /* Get crypto descriptors */ 366 crp = crypto_getreq(esph && espx ? 2 : 1); 367 if (crp == NULL) { 368 DPRINTF(("%s: failed to acquire crypto descriptors\n", 369 __func__)); 370 ESPSTAT_INC(esps_crypto); 371 m_freem(m); 372 return ENOBUFS; 373 } 374 375 /* Get IPsec-specific opaque pointer */ 376 if (esph == NULL || mtag != NULL) 377 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 378 M_XDATA, M_NOWAIT|M_ZERO); 379 else 380 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen, 381 M_XDATA, M_NOWAIT|M_ZERO); 382 if (tc == NULL) { 383 crypto_freereq(crp); 384 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 385 ESPSTAT_INC(esps_crypto); 386 m_freem(m); 387 return ENOBUFS; 388 } 389 390 tc->tc_ptr = (caddr_t) mtag; 391 392 if (esph) { 393 struct cryptodesc *crda = crp->crp_desc; 394 395 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor")); 396 397 /* Authentication descriptor */ 398 crda->crd_skip = skip; 399 crda->crd_len = m->m_pkthdr.len - (skip + alen); 400 crda->crd_inject = m->m_pkthdr.len - alen; 401 402 crda->crd_alg = esph->type; 403 crda->crd_key = sav->key_auth->key_data; 404 crda->crd_klen = _KEYBITS(sav->key_auth); 405 406 /* Copy the authenticator */ 407 if (mtag == NULL) 408 m_copydata(m, m->m_pkthdr.len - alen, alen, 409 (caddr_t) (tc + 1)); 410 411 /* Chain authentication request */ 412 crde = crda->crd_next; 413 } else { 414 crde = crp->crp_desc; 415 } 416 417 /* Crypto operation descriptor */ 418 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 419 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 420 crp->crp_buf = (caddr_t) m; 421 crp->crp_callback = esp_input_cb; 422 crp->crp_sid = sav->tdb_cryptoid; 423 crp->crp_opaque = (caddr_t) tc; 424 425 /* These are passed as-is to the callback */ 426 tc->tc_spi = sav->spi; 427 tc->tc_dst = sav->sah->saidx.dst; 428 tc->tc_proto = sav->sah->saidx.proto; 429 tc->tc_protoff = protoff; 430 tc->tc_skip = skip; 431 KEY_ADDREFSA(sav); 432 tc->tc_sav = sav; 433 434 /* Decryption descriptor */ 435 if (espx) { 436 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor")); 437 crde->crd_skip = skip + hlen; 438 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 439 crde->crd_inject = skip + hlen - sav->ivlen; 440 441 crde->crd_alg = espx->type; 442 crde->crd_key = sav->key_enc->key_data; 443 crde->crd_klen = _KEYBITS(sav->key_enc); 444 /* XXX Rounds ? */ 445 } 446 447 if (mtag == NULL) 448 return crypto_dispatch(crp); 449 else 450 return esp_input_cb(crp); 451} 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_MAXHASHLEN]; 460 int hlen, skip, protoff, error, alen; 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 = tc->tc_sav; 482 IPSEC_ASSERT(sav != NULL, ("null SA!")); 483 484 saidx = &sav->sah->saidx; 485 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 486 saidx->dst.sa.sa_family == AF_INET6, 487 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 488 489 esph = sav->tdb_authalgxform; 490 espx = sav->tdb_encalgxform; 491 492 /* Check for crypto errors */ 493 if (crp->crp_etype) { 494 /* Reset the session ID */ 495 if (sav->tdb_cryptoid != 0) 496 sav->tdb_cryptoid = crp->crp_sid; 497 498 if (crp->crp_etype == EAGAIN) 499 return (crypto_dispatch(crp)); 500 501 ESPSTAT_INC(esps_noxform); 502 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 503 error = crp->crp_etype; 504 goto bad; 505 } 506 507 /* Shouldn't happen... */ 508 if (m == NULL) { 509 ESPSTAT_INC(esps_crypto); 510 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 511 error = EINVAL; 512 goto bad; 513 } 514 ESPSTAT_INC(esps_hist[sav->alg_enc]); 515 516 /* If authentication was performed, check now. */ 517 if (esph != NULL) { 518 switch (esph->type) { 519 case CRYPTO_SHA2_256_HMAC: 520 case CRYPTO_SHA2_384_HMAC: 521 case CRYPTO_SHA2_512_HMAC: 522 alen = esph->hashsize/2; 523 break; 524 default: 525 alen = AH_HMAC_HASHLEN; 526 break; 527 } 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 AHSTAT_INC(ahs_hist[sav->alg_auth]); 534 if (mtag == NULL) { 535 /* Copy the authenticator from the packet */ 536 m_copydata(m, m->m_pkthdr.len - alen, 537 alen, aalg); 538 539 ptr = (caddr_t) (tc + 1); 540 541 /* Verify authenticator */ 542 if (bcmp(ptr, aalg, alen) != 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 ESPSTAT_INC(esps_badauth); 549 error = EACCES; 550 goto bad; 551 } 552 } 553 554 /* Remove trailing authenticator */ 555 m_adj(m, -alen); 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 ESPSTAT_INC(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 ESPSTAT_INC(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 ESPSTAT_INC(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 ESPSTAT_INC(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 switch (saidx->dst.sa.sa_family) { 635#ifdef INET6 636 case AF_INET6: 637 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); 638 break; 639#endif 640#ifdef INET 641 case AF_INET: 642 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); 643 break; 644#endif 645 default: 646 panic("%s: Unexpected address family: %d saidx=%p", __func__, 647 saidx->dst.sa.sa_family, saidx); 648 } 649 650 KEY_FREESAV(&sav); 651 return error; 652bad: 653 if (sav) 654 KEY_FREESAV(&sav); 655 if (m != NULL) 656 m_freem(m); 657 if (tc != NULL) 658 free(tc, M_XDATA); 659 if (crp != NULL) 660 crypto_freereq(crp); 661 return error; 662} 663 664/* 665 * ESP output routine, called by ipsec[46]_process_packet(). 666 */ 667static int 668esp_output( 669 struct mbuf *m, 670 struct ipsecrequest *isr, 671 struct mbuf **mp, 672 int skip, 673 int protoff 674) 675{ 676 struct enc_xform *espx; 677 struct auth_hash *esph; 678 int hlen, rlen, padding, blks, alen, i, roff; 679 struct mbuf *mo = (struct mbuf *) NULL; 680 struct tdb_crypto *tc; 681 struct secasvar *sav; 682 struct secasindex *saidx; 683 unsigned char *pad; 684 u_int8_t prot; 685 int error, maxpacketsize; 686 687 struct cryptodesc *crde = NULL, *crda = NULL; 688 struct cryptop *crp; 689 690 sav = isr->sav; 691 IPSEC_ASSERT(sav != NULL, ("null SA")); 692 esph = sav->tdb_authalgxform; 693 espx = sav->tdb_encalgxform; 694 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 695 696 if (sav->flags & SADB_X_EXT_OLD) 697 hlen = sizeof (struct esp) + sav->ivlen; 698 else 699 hlen = sizeof (struct newesp) + sav->ivlen; 700 701 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 702 /* 703 * NB: The null encoding transform has a blocksize of 4 704 * so that headers are properly aligned. 705 */ 706 blks = espx->blocksize; /* IV blocksize */ 707 708 /* XXX clamp padding length a la KAME??? */ 709 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 710 711 if (esph) 712 switch (esph->type) { 713 case CRYPTO_SHA2_256_HMAC: 714 case CRYPTO_SHA2_384_HMAC: 715 case CRYPTO_SHA2_512_HMAC: 716 alen = esph->hashsize/2; 717 break; 718 default: 719 alen = AH_HMAC_HASHLEN; 720 break; 721 } 722 else 723 alen = 0; 724 725 ESPSTAT_INC(esps_output); 726 727 saidx = &sav->sah->saidx; 728 /* Check for maximum packet size violations. */ 729 switch (saidx->dst.sa.sa_family) { 730#ifdef INET 731 case AF_INET: 732 maxpacketsize = IP_MAXPACKET; 733 break; 734#endif /* INET */ 735#ifdef INET6 736 case AF_INET6: 737 maxpacketsize = IPV6_MAXPACKET; 738 break; 739#endif /* INET6 */ 740 default: 741 DPRINTF(("%s: unknown/unsupported protocol " 742 "family %d, SA %s/%08lx\n", __func__, 743 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst), 744 (u_long) ntohl(sav->spi))); 745 ESPSTAT_INC(esps_nopf); 746 error = EPFNOSUPPORT; 747 goto bad; 748 } 749 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 750 DPRINTF(("%s: packet in SA %s/%08lx got too big " 751 "(len %u, max len %u)\n", __func__, 752 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi), 753 skip + hlen + rlen + padding + alen, maxpacketsize)); 754 ESPSTAT_INC(esps_toobig); 755 error = EMSGSIZE; 756 goto bad; 757 } 758 759 /* Update the counters. */ 760 ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip); 761 762 m = m_unshare(m, M_NOWAIT); 763 if (m == NULL) { 764 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 765 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 766 ESPSTAT_INC(esps_hdrops); 767 error = ENOBUFS; 768 goto bad; 769 } 770 771 /* Inject ESP header. */ 772 mo = m_makespace(m, skip, hlen, &roff); 773 if (mo == NULL) { 774 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 775 __func__, hlen, ipsec_address(&saidx->dst), 776 (u_long) ntohl(sav->spi))); 777 ESPSTAT_INC(esps_hdrops); /* XXX diffs from openbsd */ 778 error = ENOBUFS; 779 goto bad; 780 } 781 782 /* Initialize ESP header. */ 783 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t)); 784 if (sav->replay) { 785 u_int32_t replay; 786 787#ifdef REGRESSION 788 /* Emulate replay attack when ipsec_replay is TRUE. */ 789 if (!V_ipsec_replay) 790#endif 791 sav->replay->count++; 792 replay = htonl(sav->replay->count); 793 bcopy((caddr_t) &replay, 794 mtod(mo, caddr_t) + roff + sizeof(u_int32_t), 795 sizeof(u_int32_t)); 796 } 797 798 /* 799 * Add padding -- better to do it ourselves than use the crypto engine, 800 * although if/when we support compression, we'd have to do that. 801 */ 802 pad = (u_char *) m_pad(m, padding + alen); 803 if (pad == NULL) { 804 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 805 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 806 m = NULL; /* NB: free'd by m_pad */ 807 error = ENOBUFS; 808 goto bad; 809 } 810 811 /* 812 * Add padding: random, zero, or self-describing. 813 * XXX catch unexpected setting 814 */ 815 switch (sav->flags & SADB_X_EXT_PMASK) { 816 case SADB_X_EXT_PRAND: 817 (void) read_random(pad, padding - 2); 818 break; 819 case SADB_X_EXT_PZERO: 820 bzero(pad, padding - 2); 821 break; 822 case SADB_X_EXT_PSEQ: 823 for (i = 0; i < padding - 2; i++) 824 pad[i] = i+1; 825 break; 826 } 827 828 /* Fix padding length and Next Protocol in padding itself. */ 829 pad[padding - 2] = padding - 2; 830 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 831 832 /* Fix Next Protocol in IPv4/IPv6 header. */ 833 prot = IPPROTO_ESP; 834 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 835 836 /* Get crypto descriptors. */ 837 crp = crypto_getreq(esph && espx ? 2 : 1); 838 if (crp == NULL) { 839 DPRINTF(("%s: failed to acquire crypto descriptors\n", 840 __func__)); 841 ESPSTAT_INC(esps_crypto); 842 error = ENOBUFS; 843 goto bad; 844 } 845 846 if (espx) { 847 crde = crp->crp_desc; 848 crda = crde->crd_next; 849 850 /* Encryption descriptor. */ 851 crde->crd_skip = skip + hlen; 852 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 853 crde->crd_flags = CRD_F_ENCRYPT; 854 crde->crd_inject = skip + hlen - sav->ivlen; 855 856 /* Encryption operation. */ 857 crde->crd_alg = espx->type; 858 crde->crd_key = sav->key_enc->key_data; 859 crde->crd_klen = _KEYBITS(sav->key_enc); 860 /* XXX Rounds ? */ 861 } else 862 crda = crp->crp_desc; 863 864 /* IPsec-specific opaque crypto info. */ 865 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 866 M_XDATA, M_NOWAIT|M_ZERO); 867 if (tc == NULL) { 868 crypto_freereq(crp); 869 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 870 ESPSTAT_INC(esps_crypto); 871 error = ENOBUFS; 872 goto bad; 873 } 874 875 /* Callback parameters */ 876 tc->tc_isr = isr; 877 KEY_ADDREFSA(sav); 878 tc->tc_sav = sav; 879 tc->tc_spi = sav->spi; 880 tc->tc_dst = saidx->dst; 881 tc->tc_proto = saidx->proto; 882 883 /* Crypto operation descriptor. */ 884 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 885 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 886 crp->crp_buf = (caddr_t) m; 887 crp->crp_callback = esp_output_cb; 888 crp->crp_opaque = (caddr_t) tc; 889 crp->crp_sid = sav->tdb_cryptoid; 890 891 if (esph) { 892 /* Authentication descriptor. */ 893 crda->crd_skip = skip; 894 crda->crd_len = m->m_pkthdr.len - (skip + alen); 895 crda->crd_inject = m->m_pkthdr.len - alen; 896 897 /* Authentication operation. */ 898 crda->crd_alg = esph->type; 899 crda->crd_key = sav->key_auth->key_data; 900 crda->crd_klen = _KEYBITS(sav->key_auth); 901 } 902 903 return crypto_dispatch(crp); 904bad: 905 if (m) 906 m_freem(m); 907 return (error); 908} 909 910/* 911 * ESP output callback from the crypto driver. 912 */ 913static int 914esp_output_cb(struct cryptop *crp) 915{ 916 struct tdb_crypto *tc; 917 struct ipsecrequest *isr; 918 struct secasvar *sav; 919 struct mbuf *m; 920 int error; 921 922 tc = (struct tdb_crypto *) crp->crp_opaque; 923 IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); 924 m = (struct mbuf *) crp->crp_buf; 925 926 isr = tc->tc_isr; 927 IPSECREQUEST_LOCK(isr); 928 sav = tc->tc_sav; 929 /* With the isr lock released SA pointer can be updated. */ 930 if (sav != isr->sav) { 931 ESPSTAT_INC(esps_notdb); 932 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 933 __func__, ipsec_address(&tc->tc_dst), 934 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 935 error = ENOBUFS; /*XXX*/ 936 goto bad; 937 } 938 939 /* Check for crypto errors. */ 940 if (crp->crp_etype) { 941 /* Reset session ID. */ 942 if (sav->tdb_cryptoid != 0) 943 sav->tdb_cryptoid = crp->crp_sid; 944 945 if (crp->crp_etype == EAGAIN) { 946 IPSECREQUEST_UNLOCK(isr); 947 return (crypto_dispatch(crp)); 948 } 949 950 ESPSTAT_INC(esps_noxform); 951 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 952 error = crp->crp_etype; 953 goto bad; 954 } 955 956 /* Shouldn't happen... */ 957 if (m == NULL) { 958 ESPSTAT_INC(esps_crypto); 959 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 960 error = EINVAL; 961 goto bad; 962 } 963 ESPSTAT_INC(esps_hist[sav->alg_enc]); 964 if (sav->tdb_authalgxform != NULL) 965 AHSTAT_INC(ahs_hist[sav->alg_auth]); 966 967 /* Release crypto descriptors. */ 968 free(tc, M_XDATA); 969 crypto_freereq(crp); 970 971#ifdef REGRESSION 972 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 973 if (V_ipsec_integrity) { 974 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN]; 975 struct auth_hash *esph; 976 977 /* 978 * Corrupt HMAC if we want to test integrity verification of 979 * the other side. 980 */ 981 esph = sav->tdb_authalgxform; 982 if (esph != NULL) { 983 int alen; 984 985 switch (esph->type) { 986 case CRYPTO_SHA2_256_HMAC: 987 case CRYPTO_SHA2_384_HMAC: 988 case CRYPTO_SHA2_512_HMAC: 989 alen = esph->hashsize/2; 990 break; 991 default: 992 alen = AH_HMAC_HASHLEN; 993 break; 994 } 995 m_copyback(m, m->m_pkthdr.len - alen, 996 alen, ipseczeroes); 997 } 998 } 999#endif 1000 1001 /* NB: m is reclaimed by ipsec_process_done. */ 1002 error = ipsec_process_done(m, isr); 1003 KEY_FREESAV(&sav); 1004 IPSECREQUEST_UNLOCK(isr); 1005 return error; 1006bad: 1007 if (sav) 1008 KEY_FREESAV(&sav); 1009 IPSECREQUEST_UNLOCK(isr); 1010 if (m) 1011 m_freem(m); 1012 free(tc, M_XDATA); 1013 crypto_freereq(crp); 1014 return error; 1015} 1016 1017static struct xformsw esp_xformsw = { 1018 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 1019 esp_init, esp_zeroize, esp_input, 1020 esp_output 1021}; 1022 1023static void 1024esp_attach(void) 1025{ 1026 1027 xform_register(&esp_xformsw); 1028} 1029SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL); 1030