xform_esp.c revision 286000
1/* $FreeBSD: head/sys/netipsec/xform_esp.c 286000 2015-07-29 07:15:16Z jmg $ */ 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/lock.h> 48#include <sys/random.h> 49#include <sys/rwlock.h> 50#include <sys/sysctl.h> 51 52#include <net/if.h> 53#include <net/vnet.h> 54 55#include <netinet/in.h> 56#include <netinet/in_systm.h> 57#include <netinet/ip.h> 58#include <netinet/ip_ecn.h> 59#include <netinet/ip6.h> 60 61#include <netipsec/ipsec.h> 62#include <netipsec/ah.h> 63#include <netipsec/ah_var.h> 64#include <netipsec/esp.h> 65#include <netipsec/esp_var.h> 66#include <netipsec/xform.h> 67 68#ifdef INET6 69#include <netinet6/ip6_var.h> 70#include <netipsec/ipsec6.h> 71#include <netinet6/ip6_ecn.h> 72#endif 73 74#include <netipsec/key.h> 75#include <netipsec/key_debug.h> 76 77#include <opencrypto/cryptodev.h> 78#include <opencrypto/xform.h> 79 80VNET_DEFINE(int, esp_enable) = 1; 81VNET_PCPUSTAT_DEFINE(struct espstat, espstat); 82VNET_PCPUSTAT_SYSINIT(espstat); 83 84#ifdef VIMAGE 85VNET_PCPUSTAT_SYSUNINIT(espstat); 86#endif /* VIMAGE */ 87 88SYSCTL_DECL(_net_inet_esp); 89SYSCTL_INT(_net_inet_esp, OID_AUTO, esp_enable, 90 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(esp_enable), 0, ""); 91SYSCTL_VNET_PCPUSTAT(_net_inet_esp, IPSECCTL_STATS, stats, 92 struct espstat, espstat, 93 "ESP statistics (struct espstat, netipsec/esp_var.h"); 94 95static int esp_input_cb(struct cryptop *op); 96static int esp_output_cb(struct cryptop *crp); 97 98/* 99 * NB: this is public for use by the PF_KEY support. 100 * NB: if you add support here; be sure to add code to esp_attach below! 101 */ 102struct enc_xform * 103esp_algorithm_lookup(int alg) 104{ 105 if (alg >= ESP_ALG_MAX) 106 return NULL; 107 switch (alg) { 108 case SADB_EALG_DESCBC: 109 return &enc_xform_des; 110 case SADB_EALG_3DESCBC: 111 return &enc_xform_3des; 112 case SADB_X_EALG_AES: 113 return &enc_xform_rijndael128; 114 case SADB_X_EALG_BLOWFISHCBC: 115 return &enc_xform_blf; 116 case SADB_X_EALG_CAST128CBC: 117 return &enc_xform_cast5; 118 case SADB_X_EALG_SKIPJACK: 119 return &enc_xform_skipjack; 120 case SADB_EALG_NULL: 121 return &enc_xform_null; 122 case SADB_X_EALG_CAMELLIACBC: 123 return &enc_xform_camellia; 124 case SADB_X_EALG_AESCTR: 125 return &enc_xform_aes_icm; 126 case SADB_X_EALG_AESGCM16: 127 return &enc_xform_aes_nist_gcm; 128 case SADB_X_EALG_AESGMAC: 129 return &enc_xform_aes_nist_gmac; 130 } 131 return NULL; 132} 133 134size_t 135esp_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 ("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) + EALG_MAX_BLOCK_LEN + 9 + 16; 161 } 162 return size; 163} 164 165/* 166 * esp_init() is called when an SPI is being set up. 167 */ 168static int 169esp_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(("%s: unsupported encryption algorithm %d\n", 179 __func__, sav->alg_enc)); 180 return EINVAL; 181 } 182 if (sav->key_enc == NULL) { 183 DPRINTF(("%s: no encoding key for %s algorithm\n", 184 __func__, txform->name)); 185 return EINVAL; 186 } 187 if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) { 188 DPRINTF(("%s: 4-byte IV not supported with protocol\n", 189 __func__)); 190 return EINVAL; 191 } 192 keylen = _KEYLEN(sav->key_enc); 193 if (txform->minkey > keylen || keylen > txform->maxkey) { 194 DPRINTF(("%s: invalid key length %u, must be in the range " 195 "[%u..%u] for algorithm %s\n", __func__, 196 keylen, txform->minkey, txform->maxkey, 197 txform->name)); 198 return EINVAL; 199 } 200 201 /* 202 * NB: The null xform needs a non-zero blocksize to keep the 203 * crypto code happy but if we use it to set ivlen then 204 * the ESP header will be processed incorrectly. The 205 * compromise is to force it to zero here. 206 */ 207 sav->ivlen = (txform == &enc_xform_null ? 0 : txform->ivsize); 208 sav->iv = (caddr_t) malloc(sav->ivlen, M_XDATA, M_WAITOK); 209 key_randomfill(sav->iv, sav->ivlen); /*XXX*/ 210 211 /* 212 * Setup AH-related state. 213 */ 214 if (sav->alg_auth != 0) { 215 error = ah_init0(sav, xsp, &cria); 216 if (error) 217 return error; 218 } 219 220 /* NB: override anything set in ah_init0 */ 221 sav->tdb_xform = xsp; 222 sav->tdb_encalgxform = txform; 223 224 /* 225 * Whenever AES-GCM is used for encryption, one 226 * of the AES authentication algorithms is chosen 227 * as well, based on the key size. 228 */ 229 if (sav->alg_enc == SADB_X_EALG_AESGCM16) { 230 switch (keylen) { 231 case AES_128_HMAC_KEY_LEN: 232 sav->alg_auth = SADB_X_AALG_AES128GMAC; 233 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_128; 234 break; 235 case AES_192_HMAC_KEY_LEN: 236 sav->alg_auth = SADB_X_AALG_AES192GMAC; 237 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_192; 238 break; 239 case AES_256_HMAC_KEY_LEN: 240 sav->alg_auth = SADB_X_AALG_AES256GMAC; 241 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_256; 242 break; 243 default: 244 DPRINTF(("%s: invalid key length %u" 245 "for algorithm %s\n", __func__, 246 keylen, txform->name)); 247 return EINVAL; 248 } 249 bzero(&cria, sizeof(cria)); 250 cria.cri_alg = sav->tdb_authalgxform->type; 251 cria.cri_klen = _KEYBITS(sav->key_enc) + 4; 252 cria.cri_key = sav->key_enc->key_data; 253 } 254 255 /* Initialize crypto session. */ 256 bzero(&crie, sizeof (crie)); 257 crie.cri_alg = sav->tdb_encalgxform->type; 258 crie.cri_klen = _KEYBITS(sav->key_enc); 259 crie.cri_key = sav->key_enc->key_data; 260 if (sav->alg_enc == SADB_X_EALG_AESGCM16) 261 arc4rand(crie.cri_iv, sav->ivlen, 0); 262 263 /* XXX Rounds ? */ 264 265 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 266 /* init both auth & enc */ 267 crie.cri_next = &cria; 268 error = crypto_newsession(&sav->tdb_cryptoid, 269 &crie, V_crypto_support); 270 } else if (sav->tdb_encalgxform) { 271 error = crypto_newsession(&sav->tdb_cryptoid, 272 &crie, V_crypto_support); 273 } else if (sav->tdb_authalgxform) { 274 error = crypto_newsession(&sav->tdb_cryptoid, 275 &cria, V_crypto_support); 276 } else { 277 /* XXX cannot happen? */ 278 DPRINTF(("%s: no encoding OR authentication xform!\n", 279 __func__)); 280 error = EINVAL; 281 } 282 return error; 283} 284 285/* 286 * Paranoia. 287 */ 288static int 289esp_zeroize(struct secasvar *sav) 290{ 291 /* NB: ah_zerorize free's the crypto session state */ 292 int error = ah_zeroize(sav); 293 294 if (sav->key_enc) 295 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc)); 296 if (sav->iv) { 297 free(sav->iv, M_XDATA); 298 sav->iv = NULL; 299 } 300 sav->tdb_encalgxform = NULL; 301 sav->tdb_xform = NULL; 302 return error; 303} 304 305/* 306 * ESP input processing, called (eventually) through the protocol switch. 307 */ 308static int 309esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 310{ 311 char buf[128]; 312 struct auth_hash *esph; 313 struct enc_xform *espx; 314 struct tdb_crypto *tc; 315 int plen, alen, hlen; 316 struct newesp *esp; 317 struct cryptodesc *crde; 318 struct cryptop *crp; 319 320 IPSEC_ASSERT(sav != NULL, ("null SA")); 321 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); 322 323 /* Valid IP Packet length ? */ 324 if ( (skip&3) || (m->m_pkthdr.len&3) ){ 325 DPRINTF(("%s: misaligned packet, skip %u pkt len %u", 326 __func__, skip, m->m_pkthdr.len)); 327 ESPSTAT_INC(esps_badilen); 328 m_freem(m); 329 return EINVAL; 330 } 331 /* XXX don't pullup, just copy header */ 332 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 333 334 esph = sav->tdb_authalgxform; 335 espx = sav->tdb_encalgxform; 336 337 /* Determine the ESP header and auth length */ 338 if (sav->flags & SADB_X_EXT_OLD) 339 hlen = sizeof (struct esp) + sav->ivlen; 340 else 341 hlen = sizeof (struct newesp) + sav->ivlen; 342 343 alen = xform_ah_authsize(esph); 344 345 /* 346 * Verify payload length is multiple of encryption algorithm 347 * block size. 348 * 349 * NB: This works for the null algorithm because the blocksize 350 * is 4 and all packets must be 4-byte aligned regardless 351 * of the algorithm. 352 */ 353 plen = m->m_pkthdr.len - (skip + hlen + alen); 354 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 355 if (!espx || sav->alg_enc != SADB_X_EALG_AESGCM16) { 356 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 357 " SA %s/%08lx\n", __func__, 358 plen, espx->blocksize, ipsec_address(&sav->sah->saidx.dst, 359 buf, sizeof(buf)), (u_long) ntohl(sav->spi))); 360 ESPSTAT_INC(esps_badilen); 361 m_freem(m); 362 return EINVAL; 363 } 364 } 365 366 /* 367 * Check sequence number. 368 */ 369 if (esph != NULL && sav->replay != NULL && 370 !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) { 371 DPRINTF(("%s: packet replay check for %s\n", __func__, 372 ipsec_logsastr(sav, buf, sizeof(buf)))); /*XXX*/ 373 ESPSTAT_INC(esps_replay); 374 m_freem(m); 375 return ENOBUFS; /*XXX*/ 376 } 377 378 /* Update the counters */ 379 ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen)); 380 381 /* Get crypto descriptors */ 382 crp = crypto_getreq(esph && espx ? 2 : 1); 383 if (crp == NULL) { 384 DPRINTF(("%s: failed to acquire crypto descriptors\n", 385 __func__)); 386 ESPSTAT_INC(esps_crypto); 387 m_freem(m); 388 return ENOBUFS; 389 } 390 391 /* Get IPsec-specific opaque pointer */ 392 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen, 393 M_XDATA, M_NOWAIT | M_ZERO); 394 if (tc == NULL) { 395 crypto_freereq(crp); 396 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 397 ESPSTAT_INC(esps_crypto); 398 m_freem(m); 399 return ENOBUFS; 400 } 401 402 if (esph != NULL) { 403 struct cryptodesc *crda = crp->crp_desc; 404 405 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor")); 406 407 /* Authentication descriptor */ 408 crda->crd_skip = skip; 409 if (espx && espx->type == CRYPTO_AES_NIST_GCM_16) 410 crda->crd_len = hlen - sav->ivlen; 411 else 412 crda->crd_len = m->m_pkthdr.len - (skip + alen); 413 crda->crd_inject = m->m_pkthdr.len - alen; 414 415 crda->crd_alg = esph->type; 416 if (espx && (espx->type == CRYPTO_AES_NIST_GCM_16)) { 417 crda->crd_key = sav->key_enc->key_data; 418 crda->crd_klen = _KEYBITS(sav->key_enc); 419 } else { 420 crda->crd_key = sav->key_auth->key_data; 421 crda->crd_klen = _KEYBITS(sav->key_auth); 422 } 423 424 /* Copy the authenticator */ 425 m_copydata(m, m->m_pkthdr.len - alen, alen, 426 (caddr_t) (tc + 1)); 427 428 /* Chain authentication request */ 429 crde = crda->crd_next; 430 } else { 431 crde = crp->crp_desc; 432 } 433 434 /* Crypto operation descriptor */ 435 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 436 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 437 crp->crp_buf = (caddr_t) m; 438 crp->crp_callback = esp_input_cb; 439 crp->crp_sid = sav->tdb_cryptoid; 440 crp->crp_opaque = (caddr_t) tc; 441 442 /* These are passed as-is to the callback */ 443 tc->tc_spi = sav->spi; 444 tc->tc_dst = sav->sah->saidx.dst; 445 tc->tc_proto = sav->sah->saidx.proto; 446 tc->tc_protoff = protoff; 447 tc->tc_skip = skip; 448 KEY_ADDREFSA(sav); 449 tc->tc_sav = sav; 450 451 /* Decryption descriptor */ 452 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor")); 453 crde->crd_skip = skip + hlen; 454 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 455 crde->crd_inject = skip + hlen - sav->ivlen; 456 457 crde->crd_alg = espx->type; 458 crde->crd_key = sav->key_enc->key_data; 459 crde->crd_klen = _KEYBITS(sav->key_enc); 460 if (espx && (espx->type == CRYPTO_AES_NIST_GCM_16)) 461 crde->crd_flags |= CRD_F_IV_EXPLICIT; 462 463 /* XXX Rounds ? */ 464 465 return (crypto_dispatch(crp)); 466} 467 468/* 469 * ESP input callback from the crypto driver. 470 */ 471static int 472esp_input_cb(struct cryptop *crp) 473{ 474 char buf[128]; 475 u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN]; 476 int hlen, skip, protoff, error, alen; 477 struct mbuf *m; 478 struct cryptodesc *crd; 479 struct auth_hash *esph; 480 struct enc_xform *espx; 481 struct tdb_crypto *tc; 482 struct secasvar *sav; 483 struct secasindex *saidx; 484 caddr_t ptr; 485 486 crd = crp->crp_desc; 487 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!")); 488 489 tc = (struct tdb_crypto *) crp->crp_opaque; 490 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!")); 491 skip = tc->tc_skip; 492 protoff = tc->tc_protoff; 493 m = (struct mbuf *) crp->crp_buf; 494 495 sav = tc->tc_sav; 496 IPSEC_ASSERT(sav != NULL, ("null SA!")); 497 498 saidx = &sav->sah->saidx; 499 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 500 saidx->dst.sa.sa_family == AF_INET6, 501 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 502 503 esph = sav->tdb_authalgxform; 504 espx = sav->tdb_encalgxform; 505 506 /* Check for crypto errors */ 507 if (crp->crp_etype) { 508 /* Reset the session ID */ 509 if (sav->tdb_cryptoid != 0) 510 sav->tdb_cryptoid = crp->crp_sid; 511 512 if (crp->crp_etype == EAGAIN) 513 return (crypto_dispatch(crp)); 514 515 ESPSTAT_INC(esps_noxform); 516 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 517 error = crp->crp_etype; 518 goto bad; 519 } 520 521 /* Shouldn't happen... */ 522 if (m == NULL) { 523 ESPSTAT_INC(esps_crypto); 524 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 525 error = EINVAL; 526 goto bad; 527 } 528 ESPSTAT_INC(esps_hist[sav->alg_enc]); 529 530 /* If authentication was performed, check now. */ 531 if (esph != NULL) { 532 alen = xform_ah_authsize(esph); 533 AHSTAT_INC(ahs_hist[sav->alg_auth]); 534 /* Copy the authenticator from the packet */ 535 m_copydata(m, m->m_pkthdr.len - alen, alen, aalg); 536 ptr = (caddr_t) (tc + 1); 537 538 /* Verify authenticator */ 539 if (bcmp(ptr, aalg, alen) != 0) { 540 DPRINTF(("%s: authentication hash mismatch for " 541 "packet in SA %s/%08lx\n", __func__, 542 ipsec_address(&saidx->dst, buf, sizeof(buf)), 543 (u_long) ntohl(sav->spi))); 544 ESPSTAT_INC(esps_badauth); 545 error = EACCES; 546 goto bad; 547 } 548 549 /* Remove trailing authenticator */ 550 m_adj(m, -alen); 551 } 552 553 /* Release the crypto descriptors */ 554 free(tc, M_XDATA), tc = NULL; 555 crypto_freereq(crp), crp = NULL; 556 557 /* 558 * Packet is now decrypted. 559 */ 560 m->m_flags |= M_DECRYPTED; 561 562 /* 563 * Update replay sequence number, if appropriate. 564 */ 565 if (sav->replay) { 566 u_int32_t seq; 567 568 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 569 sizeof (seq), (caddr_t) &seq); 570 if (ipsec_updatereplay(ntohl(seq), sav)) { 571 DPRINTF(("%s: packet replay check for %s\n", __func__, 572 ipsec_logsastr(sav, buf, sizeof(buf)))); 573 ESPSTAT_INC(esps_replay); 574 error = ENOBUFS; 575 goto bad; 576 } 577 } 578 579 /* Determine the ESP header length */ 580 if (sav->flags & SADB_X_EXT_OLD) 581 hlen = sizeof (struct esp) + sav->ivlen; 582 else 583 hlen = sizeof (struct newesp) + sav->ivlen; 584 585 /* Remove the ESP header and IV from the mbuf. */ 586 error = m_striphdr(m, skip, hlen); 587 if (error) { 588 ESPSTAT_INC(esps_hdrops); 589 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 590 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 591 (u_long) ntohl(sav->spi))); 592 goto bad; 593 } 594 595 /* Save the last three bytes of decrypted data */ 596 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 597 598 /* Verify pad length */ 599 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 600 ESPSTAT_INC(esps_badilen); 601 DPRINTF(("%s: invalid padding length %d for %u byte packet " 602 "in SA %s/%08lx\n", __func__, lastthree[1], 603 m->m_pkthdr.len - skip, 604 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 605 (u_long) ntohl(sav->spi))); 606 error = EINVAL; 607 goto bad; 608 } 609 610 /* Verify correct decryption by checking the last padding bytes */ 611 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 612 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 613 ESPSTAT_INC(esps_badenc); 614 DPRINTF(("%s: decryption failed for packet in " 615 "SA %s/%08lx\n", __func__, ipsec_address( 616 &sav->sah->saidx.dst, buf, sizeof(buf)), 617 (u_long) ntohl(sav->spi))); 618 error = EINVAL; 619 goto bad; 620 } 621 } 622 623 /* Trim the mbuf chain to remove trailing authenticator and padding */ 624 m_adj(m, -(lastthree[1] + 2)); 625 626 /* Restore the Next Protocol field */ 627 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 628 629 switch (saidx->dst.sa.sa_family) { 630#ifdef INET6 631 case AF_INET6: 632 error = ipsec6_common_input_cb(m, sav, skip, protoff); 633 break; 634#endif 635#ifdef INET 636 case AF_INET: 637 error = ipsec4_common_input_cb(m, sav, skip, protoff); 638 break; 639#endif 640 default: 641 panic("%s: Unexpected address family: %d saidx=%p", __func__, 642 saidx->dst.sa.sa_family, saidx); 643 } 644 645 KEY_FREESAV(&sav); 646 return error; 647bad: 648 if (sav) 649 KEY_FREESAV(&sav); 650 if (m != NULL) 651 m_freem(m); 652 if (tc != NULL) 653 free(tc, M_XDATA); 654 if (crp != NULL) 655 crypto_freereq(crp); 656 return error; 657} 658 659/* 660 * ESP output routine, called by ipsec[46]_process_packet(). 661 */ 662static int 663esp_output(struct mbuf *m, struct ipsecrequest *isr, struct mbuf **mp, 664 int skip, int protoff) 665{ 666 char buf[INET6_ADDRSTRLEN]; 667 struct enc_xform *espx; 668 struct auth_hash *esph; 669 int hlen, rlen, padding, blks, alen, i, roff; 670 struct mbuf *mo = (struct mbuf *) NULL; 671 struct tdb_crypto *tc; 672 struct secasvar *sav; 673 struct secasindex *saidx; 674 unsigned char *pad; 675 u_int8_t prot; 676 int error, maxpacketsize; 677 678 struct cryptodesc *crde = NULL, *crda = NULL; 679 struct cryptop *crp; 680 681 sav = isr->sav; 682 IPSEC_ASSERT(sav != NULL, ("null SA")); 683 esph = sav->tdb_authalgxform; 684 espx = sav->tdb_encalgxform; 685 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 686 687 if (sav->flags & SADB_X_EXT_OLD) 688 hlen = sizeof (struct esp) + sav->ivlen; 689 else 690 hlen = sizeof (struct newesp) + sav->ivlen; 691 692 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 693 /* 694 * NB: The null encoding transform has a blocksize of 4 695 * so that headers are properly aligned. 696 */ 697 blks = espx->ivsize; /* IV blocksize */ 698 699 /* XXX clamp padding length a la KAME??? */ 700 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 701 702 alen = xform_ah_authsize(esph); 703 704 ESPSTAT_INC(esps_output); 705 706 saidx = &sav->sah->saidx; 707 /* Check for maximum packet size violations. */ 708 switch (saidx->dst.sa.sa_family) { 709#ifdef INET 710 case AF_INET: 711 maxpacketsize = IP_MAXPACKET; 712 break; 713#endif /* INET */ 714#ifdef INET6 715 case AF_INET6: 716 maxpacketsize = IPV6_MAXPACKET; 717 break; 718#endif /* INET6 */ 719 default: 720 DPRINTF(("%s: unknown/unsupported protocol " 721 "family %d, SA %s/%08lx\n", __func__, 722 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst, 723 buf, sizeof(buf)), (u_long) ntohl(sav->spi))); 724 ESPSTAT_INC(esps_nopf); 725 error = EPFNOSUPPORT; 726 goto bad; 727 } 728 DPRINTF(("%s: skip %d hlen %d rlen %d padding %d alen %d blksd %d\n", 729 __func__, skip, hlen, rlen, padding, alen, blks)); 730 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 731 DPRINTF(("%s: packet in SA %s/%08lx got too big " 732 "(len %u, max len %u)\n", __func__, 733 ipsec_address(&saidx->dst, buf, sizeof(buf)), 734 (u_long) ntohl(sav->spi), 735 skip + hlen + rlen + padding + alen, maxpacketsize)); 736 ESPSTAT_INC(esps_toobig); 737 error = EMSGSIZE; 738 goto bad; 739 } 740 741 /* Update the counters. */ 742 ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip); 743 744 m = m_unshare(m, M_NOWAIT); 745 if (m == NULL) { 746 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 747 ipsec_address(&saidx->dst, buf, sizeof(buf)), 748 (u_long) ntohl(sav->spi))); 749 ESPSTAT_INC(esps_hdrops); 750 error = ENOBUFS; 751 goto bad; 752 } 753 754 /* Inject ESP header. */ 755 mo = m_makespace(m, skip, hlen, &roff); 756 if (mo == NULL) { 757 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 758 __func__, hlen, ipsec_address(&saidx->dst, buf, 759 sizeof(buf)), (u_long) ntohl(sav->spi))); 760 ESPSTAT_INC(esps_hdrops); /* XXX diffs from openbsd */ 761 error = ENOBUFS; 762 goto bad; 763 } 764 765 /* Initialize ESP header. */ 766 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t)); 767 if (sav->replay) { 768 u_int32_t replay; 769 770#ifdef REGRESSION 771 /* Emulate replay attack when ipsec_replay is TRUE. */ 772 if (!V_ipsec_replay) 773#endif 774 sav->replay->count++; 775 replay = htonl(sav->replay->count); 776 bcopy((caddr_t) &replay, 777 mtod(mo, caddr_t) + roff + sizeof(u_int32_t), 778 sizeof(u_int32_t)); 779 } 780 781 /* 782 * Add padding -- better to do it ourselves than use the crypto engine, 783 * although if/when we support compression, we'd have to do that. 784 */ 785 pad = (u_char *) m_pad(m, padding + alen); 786 if (pad == NULL) { 787 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 788 ipsec_address(&saidx->dst, buf, sizeof(buf)), 789 (u_long) ntohl(sav->spi))); 790 m = NULL; /* NB: free'd by m_pad */ 791 error = ENOBUFS; 792 goto bad; 793 } 794 795 /* 796 * Add padding: random, zero, or self-describing. 797 * XXX catch unexpected setting 798 */ 799 switch (sav->flags & SADB_X_EXT_PMASK) { 800 case SADB_X_EXT_PRAND: 801 (void) read_random(pad, padding - 2); 802 break; 803 case SADB_X_EXT_PZERO: 804 bzero(pad, padding - 2); 805 break; 806 case SADB_X_EXT_PSEQ: 807 for (i = 0; i < padding - 2; i++) 808 pad[i] = i+1; 809 break; 810 } 811 812 /* Fix padding length and Next Protocol in padding itself. */ 813 pad[padding - 2] = padding - 2; 814 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 815 816 /* Fix Next Protocol in IPv4/IPv6 header. */ 817 prot = IPPROTO_ESP; 818 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 819 820 /* Get crypto descriptors. */ 821 crp = crypto_getreq(esph && espx ? 2 : 1); 822 if (crp == NULL) { 823 DPRINTF(("%s: failed to acquire crypto descriptors\n", 824 __func__)); 825 ESPSTAT_INC(esps_crypto); 826 error = ENOBUFS; 827 goto bad; 828 } 829 830 if (espx) { 831 crde = crp->crp_desc; 832 crda = crde->crd_next; 833 834 /* Encryption descriptor. */ 835 crde->crd_skip = skip + hlen; 836 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 837 crde->crd_flags = CRD_F_ENCRYPT; 838 crde->crd_inject = skip + hlen - sav->ivlen; 839 840 /* Encryption operation. */ 841 crde->crd_alg = espx->type; 842 crde->crd_key = sav->key_enc->key_data; 843 crde->crd_klen = _KEYBITS(sav->key_enc); 844 if (espx->type == CRYPTO_AES_NIST_GCM_16) 845 crde->crd_flags |= CRD_F_IV_EXPLICIT; 846 /* XXX Rounds ? */ 847 } else 848 crda = crp->crp_desc; 849 850 /* IPsec-specific opaque crypto info. */ 851 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 852 M_XDATA, M_NOWAIT|M_ZERO); 853 if (tc == NULL) { 854 crypto_freereq(crp); 855 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 856 ESPSTAT_INC(esps_crypto); 857 error = ENOBUFS; 858 goto bad; 859 } 860 861 /* Callback parameters */ 862 tc->tc_isr = isr; 863 KEY_ADDREFSA(sav); 864 tc->tc_sav = sav; 865 tc->tc_spi = sav->spi; 866 tc->tc_dst = saidx->dst; 867 tc->tc_proto = saidx->proto; 868 869 /* Crypto operation descriptor. */ 870 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 871 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 872 crp->crp_buf = (caddr_t) m; 873 crp->crp_callback = esp_output_cb; 874 crp->crp_opaque = (caddr_t) tc; 875 crp->crp_sid = sav->tdb_cryptoid; 876 877 if (esph) { 878 /* Authentication descriptor. */ 879 crda->crd_skip = skip; 880 if (espx && espx->type == CRYPTO_AES_NIST_GCM_16) 881 crda->crd_len = hlen - sav->ivlen; 882 else 883 crda->crd_len = m->m_pkthdr.len - (skip + alen); 884 crda->crd_inject = m->m_pkthdr.len - alen; 885 886 /* Authentication operation. */ 887 crda->crd_alg = esph->type; 888 if (espx && espx->type == CRYPTO_AES_NIST_GCM_16) { 889 crda->crd_key = sav->key_enc->key_data; 890 crda->crd_klen = _KEYBITS(sav->key_enc); 891 } else { 892 crda->crd_key = sav->key_auth->key_data; 893 crda->crd_klen = _KEYBITS(sav->key_auth); 894 } 895 896 } 897 898 return crypto_dispatch(crp); 899bad: 900 if (m) 901 m_freem(m); 902 return (error); 903} 904 905/* 906 * ESP output callback from the crypto driver. 907 */ 908static int 909esp_output_cb(struct cryptop *crp) 910{ 911 char buf[INET6_ADDRSTRLEN]; 912 struct tdb_crypto *tc; 913 struct ipsecrequest *isr; 914 struct secasvar *sav; 915 struct mbuf *m; 916 int error; 917 918 tc = (struct tdb_crypto *) crp->crp_opaque; 919 IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); 920 m = (struct mbuf *) crp->crp_buf; 921 922 isr = tc->tc_isr; 923 IPSEC_ASSERT(isr->sp != NULL, ("NULL isr->sp")); 924 IPSECREQUEST_LOCK(isr); 925 sav = tc->tc_sav; 926 /* With the isr lock released SA pointer can be updated. */ 927 if (sav != isr->sav) { 928 ESPSTAT_INC(esps_notdb); 929 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 930 __func__, ipsec_address(&tc->tc_dst, buf, sizeof(buf)), 931 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 932 error = ENOBUFS; /*XXX*/ 933 goto bad; 934 } 935 936 /* Check for crypto errors. */ 937 if (crp->crp_etype) { 938 /* Reset session ID. */ 939 if (sav->tdb_cryptoid != 0) 940 sav->tdb_cryptoid = crp->crp_sid; 941 942 if (crp->crp_etype == EAGAIN) { 943 IPSECREQUEST_UNLOCK(isr); 944 return (crypto_dispatch(crp)); 945 } 946 947 ESPSTAT_INC(esps_noxform); 948 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 949 error = crp->crp_etype; 950 goto bad; 951 } 952 953 /* Shouldn't happen... */ 954 if (m == NULL) { 955 ESPSTAT_INC(esps_crypto); 956 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 957 error = EINVAL; 958 goto bad; 959 } 960 ESPSTAT_INC(esps_hist[sav->alg_enc]); 961 if (sav->tdb_authalgxform != NULL) 962 AHSTAT_INC(ahs_hist[sav->alg_auth]); 963 964 /* Release crypto descriptors. */ 965 free(tc, M_XDATA); 966 crypto_freereq(crp); 967 968#ifdef REGRESSION 969 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 970 if (V_ipsec_integrity) { 971 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN]; 972 struct auth_hash *esph; 973 974 /* 975 * Corrupt HMAC if we want to test integrity verification of 976 * the other side. 977 */ 978 esph = sav->tdb_authalgxform; 979 if (esph != NULL) { 980 int alen; 981 982 alen = xform_ah_authsize(esph); 983 m_copyback(m, m->m_pkthdr.len - alen, 984 alen, ipseczeroes); 985 } 986 } 987#endif 988 989 /* NB: m is reclaimed by ipsec_process_done. */ 990 error = ipsec_process_done(m, isr); 991 KEY_FREESAV(&sav); 992 IPSECREQUEST_UNLOCK(isr); 993 KEY_FREESP(&isr->sp); 994 return (error); 995bad: 996 if (sav) 997 KEY_FREESAV(&sav); 998 IPSECREQUEST_UNLOCK(isr); 999 KEY_FREESP(&isr->sp); 1000 if (m) 1001 m_freem(m); 1002 free(tc, M_XDATA); 1003 crypto_freereq(crp); 1004 return (error); 1005} 1006 1007static struct xformsw esp_xformsw = { 1008 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 1009 esp_init, esp_zeroize, esp_input, 1010 esp_output 1011}; 1012 1013static void 1014esp_attach(void) 1015{ 1016 1017 xform_register(&esp_xformsw); 1018} 1019SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL); 1020