xform_esp.c revision 286100
1/* $FreeBSD: head/sys/netipsec/xform_esp.c 286100 2015-07-31 00:23:21Z 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_EALG_NULL: 119 return &enc_xform_null; 120 case SADB_X_EALG_CAMELLIACBC: 121 return &enc_xform_camellia; 122 case SADB_X_EALG_AESCTR: 123 return &enc_xform_aes_icm; 124 case SADB_X_EALG_AESGCM16: 125 return &enc_xform_aes_nist_gcm; 126 case SADB_X_EALG_AESGMAC: 127 return &enc_xform_aes_nist_gmac; 128 } 129 return NULL; 130} 131 132size_t 133esp_hdrsiz(struct secasvar *sav) 134{ 135 size_t size; 136 137 if (sav != NULL) { 138 /*XXX not right for null algorithm--does it matter??*/ 139 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 140 ("SA with null xform")); 141 if (sav->flags & SADB_X_EXT_OLD) 142 size = sizeof (struct esp); 143 else 144 size = sizeof (struct newesp); 145 size += sav->tdb_encalgxform->blocksize + 9; 146 /*XXX need alg check???*/ 147 if (sav->tdb_authalgxform != NULL && sav->replay) 148 size += ah_hdrsiz(sav); 149 } else { 150 /* 151 * base header size 152 * + max iv length for CBC mode 153 * + max pad length 154 * + sizeof (pad length field) 155 * + sizeof (next header field) 156 * + max icv supported. 157 */ 158 size = sizeof (struct newesp) + EALG_MAX_BLOCK_LEN + 9 + 16; 159 } 160 return size; 161} 162 163/* 164 * esp_init() is called when an SPI is being set up. 165 */ 166static int 167esp_init(struct secasvar *sav, struct xformsw *xsp) 168{ 169 struct enc_xform *txform; 170 struct cryptoini cria, crie; 171 int keylen; 172 int error; 173 174 txform = esp_algorithm_lookup(sav->alg_enc); 175 if (txform == NULL) { 176 DPRINTF(("%s: unsupported encryption algorithm %d\n", 177 __func__, sav->alg_enc)); 178 return EINVAL; 179 } 180 if (sav->key_enc == NULL) { 181 DPRINTF(("%s: no encoding key for %s algorithm\n", 182 __func__, txform->name)); 183 return EINVAL; 184 } 185 if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) { 186 DPRINTF(("%s: 4-byte IV not supported with protocol\n", 187 __func__)); 188 return EINVAL; 189 } 190 keylen = _KEYLEN(sav->key_enc); 191 if (txform->minkey > keylen || keylen > txform->maxkey) { 192 DPRINTF(("%s: invalid key length %u, must be in the range " 193 "[%u..%u] for algorithm %s\n", __func__, 194 keylen, txform->minkey, txform->maxkey, 195 txform->name)); 196 return EINVAL; 197 } 198 199 /* 200 * NB: The null xform needs a non-zero blocksize to keep the 201 * crypto code happy but if we use it to set ivlen then 202 * the ESP header will be processed incorrectly. The 203 * compromise is to force it to zero here. 204 */ 205 sav->ivlen = (txform == &enc_xform_null ? 0 : txform->ivsize); 206 sav->iv = (caddr_t) malloc(sav->ivlen, M_XDATA, M_WAITOK); 207 key_randomfill(sav->iv, sav->ivlen); /*XXX*/ 208 209 /* 210 * Setup AH-related state. 211 */ 212 if (sav->alg_auth != 0) { 213 error = ah_init0(sav, xsp, &cria); 214 if (error) 215 return error; 216 } 217 218 /* NB: override anything set in ah_init0 */ 219 sav->tdb_xform = xsp; 220 sav->tdb_encalgxform = txform; 221 222 /* 223 * Whenever AES-GCM is used for encryption, one 224 * of the AES authentication algorithms is chosen 225 * as well, based on the key size. 226 */ 227 if (sav->alg_enc == SADB_X_EALG_AESGCM16) { 228 switch (keylen) { 229 case AES_128_HMAC_KEY_LEN: 230 sav->alg_auth = SADB_X_AALG_AES128GMAC; 231 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_128; 232 break; 233 case AES_192_HMAC_KEY_LEN: 234 sav->alg_auth = SADB_X_AALG_AES192GMAC; 235 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_192; 236 break; 237 case AES_256_HMAC_KEY_LEN: 238 sav->alg_auth = SADB_X_AALG_AES256GMAC; 239 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_256; 240 break; 241 default: 242 DPRINTF(("%s: invalid key length %u" 243 "for algorithm %s\n", __func__, 244 keylen, txform->name)); 245 return EINVAL; 246 } 247 bzero(&cria, sizeof(cria)); 248 cria.cri_alg = sav->tdb_authalgxform->type; 249 cria.cri_klen = _KEYBITS(sav->key_enc) + 4; 250 cria.cri_key = sav->key_enc->key_data; 251 } 252 253 /* Initialize crypto session. */ 254 bzero(&crie, sizeof (crie)); 255 crie.cri_alg = sav->tdb_encalgxform->type; 256 crie.cri_klen = _KEYBITS(sav->key_enc); 257 crie.cri_key = sav->key_enc->key_data; 258 if (sav->alg_enc == SADB_X_EALG_AESGCM16) 259 arc4rand(crie.cri_iv, sav->ivlen, 0); 260 261 /* XXX Rounds ? */ 262 263 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 264 /* init both auth & enc */ 265 crie.cri_next = &cria; 266 error = crypto_newsession(&sav->tdb_cryptoid, 267 &crie, V_crypto_support); 268 } else if (sav->tdb_encalgxform) { 269 error = crypto_newsession(&sav->tdb_cryptoid, 270 &crie, V_crypto_support); 271 } else if (sav->tdb_authalgxform) { 272 error = crypto_newsession(&sav->tdb_cryptoid, 273 &cria, V_crypto_support); 274 } else { 275 /* XXX cannot happen? */ 276 DPRINTF(("%s: no encoding OR authentication xform!\n", 277 __func__)); 278 error = EINVAL; 279 } 280 return error; 281} 282 283/* 284 * Paranoia. 285 */ 286static int 287esp_zeroize(struct secasvar *sav) 288{ 289 /* NB: ah_zerorize free's the crypto session state */ 290 int error = ah_zeroize(sav); 291 292 if (sav->key_enc) 293 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc)); 294 if (sav->iv) { 295 free(sav->iv, M_XDATA); 296 sav->iv = NULL; 297 } 298 sav->tdb_encalgxform = NULL; 299 sav->tdb_xform = NULL; 300 return error; 301} 302 303/* 304 * ESP input processing, called (eventually) through the protocol switch. 305 */ 306static int 307esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 308{ 309 char buf[128]; 310 struct auth_hash *esph; 311 struct enc_xform *espx; 312 struct tdb_crypto *tc; 313 int plen, alen, hlen; 314 struct newesp *esp; 315 struct cryptodesc *crde; 316 struct cryptop *crp; 317 318 IPSEC_ASSERT(sav != NULL, ("null SA")); 319 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); 320 321 /* Valid IP Packet length ? */ 322 if ( (skip&3) || (m->m_pkthdr.len&3) ){ 323 DPRINTF(("%s: misaligned packet, skip %u pkt len %u", 324 __func__, skip, m->m_pkthdr.len)); 325 ESPSTAT_INC(esps_badilen); 326 m_freem(m); 327 return EINVAL; 328 } 329 /* XXX don't pullup, just copy header */ 330 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 331 332 esph = sav->tdb_authalgxform; 333 espx = sav->tdb_encalgxform; 334 335 /* Determine the ESP header and auth length */ 336 if (sav->flags & SADB_X_EXT_OLD) 337 hlen = sizeof (struct esp) + sav->ivlen; 338 else 339 hlen = sizeof (struct newesp) + sav->ivlen; 340 341 alen = xform_ah_authsize(esph); 342 343 /* 344 * Verify payload length is multiple of encryption algorithm 345 * block size. 346 * 347 * NB: This works for the null algorithm because the blocksize 348 * is 4 and all packets must be 4-byte aligned regardless 349 * of the algorithm. 350 */ 351 plen = m->m_pkthdr.len - (skip + hlen + alen); 352 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 353 if (!espx || sav->alg_enc != SADB_X_EALG_AESGCM16) { 354 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 355 " SA %s/%08lx\n", __func__, 356 plen, espx->blocksize, ipsec_address(&sav->sah->saidx.dst, 357 buf, sizeof(buf)), (u_long) ntohl(sav->spi))); 358 ESPSTAT_INC(esps_badilen); 359 m_freem(m); 360 return EINVAL; 361 } 362 } 363 364 /* 365 * Check sequence number. 366 */ 367 if (esph != NULL && sav->replay != NULL && 368 !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) { 369 DPRINTF(("%s: packet replay check for %s\n", __func__, 370 ipsec_logsastr(sav, buf, sizeof(buf)))); /*XXX*/ 371 ESPSTAT_INC(esps_replay); 372 m_freem(m); 373 return ENOBUFS; /*XXX*/ 374 } 375 376 /* Update the counters */ 377 ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen)); 378 379 /* Get crypto descriptors */ 380 crp = crypto_getreq(esph && espx ? 2 : 1); 381 if (crp == NULL) { 382 DPRINTF(("%s: failed to acquire crypto descriptors\n", 383 __func__)); 384 ESPSTAT_INC(esps_crypto); 385 m_freem(m); 386 return ENOBUFS; 387 } 388 389 /* Get IPsec-specific opaque pointer */ 390 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen, 391 M_XDATA, M_NOWAIT | M_ZERO); 392 if (tc == NULL) { 393 crypto_freereq(crp); 394 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 395 ESPSTAT_INC(esps_crypto); 396 m_freem(m); 397 return ENOBUFS; 398 } 399 400 if (esph != NULL) { 401 struct cryptodesc *crda = crp->crp_desc; 402 403 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor")); 404 405 /* Authentication descriptor */ 406 crda->crd_skip = skip; 407 if (espx && espx->type == CRYPTO_AES_NIST_GCM_16) 408 crda->crd_len = hlen - sav->ivlen; 409 else 410 crda->crd_len = m->m_pkthdr.len - (skip + alen); 411 crda->crd_inject = m->m_pkthdr.len - alen; 412 413 crda->crd_alg = esph->type; 414 if (espx && (espx->type == CRYPTO_AES_NIST_GCM_16)) { 415 crda->crd_key = sav->key_enc->key_data; 416 crda->crd_klen = _KEYBITS(sav->key_enc); 417 } else { 418 crda->crd_key = sav->key_auth->key_data; 419 crda->crd_klen = _KEYBITS(sav->key_auth); 420 } 421 422 /* Copy the authenticator */ 423 m_copydata(m, m->m_pkthdr.len - alen, alen, 424 (caddr_t) (tc + 1)); 425 426 /* Chain authentication request */ 427 crde = crda->crd_next; 428 } else { 429 crde = crp->crp_desc; 430 } 431 432 /* Crypto operation descriptor */ 433 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 434 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 435 crp->crp_buf = (caddr_t) m; 436 crp->crp_callback = esp_input_cb; 437 crp->crp_sid = sav->tdb_cryptoid; 438 crp->crp_opaque = (caddr_t) tc; 439 440 /* These are passed as-is to the callback */ 441 tc->tc_spi = sav->spi; 442 tc->tc_dst = sav->sah->saidx.dst; 443 tc->tc_proto = sav->sah->saidx.proto; 444 tc->tc_protoff = protoff; 445 tc->tc_skip = skip; 446 KEY_ADDREFSA(sav); 447 tc->tc_sav = sav; 448 449 /* Decryption descriptor */ 450 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor")); 451 crde->crd_skip = skip + hlen; 452 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 453 crde->crd_inject = skip + hlen - sav->ivlen; 454 455 crde->crd_alg = espx->type; 456 crde->crd_key = sav->key_enc->key_data; 457 crde->crd_klen = _KEYBITS(sav->key_enc); 458 if (espx && (espx->type == CRYPTO_AES_NIST_GCM_16)) 459 crde->crd_flags |= CRD_F_IV_EXPLICIT; 460 461 /* XXX Rounds ? */ 462 463 return (crypto_dispatch(crp)); 464} 465 466/* 467 * ESP input callback from the crypto driver. 468 */ 469static int 470esp_input_cb(struct cryptop *crp) 471{ 472 char buf[128]; 473 u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN]; 474 int hlen, skip, protoff, error, alen; 475 struct mbuf *m; 476 struct cryptodesc *crd; 477 struct auth_hash *esph; 478 struct enc_xform *espx; 479 struct tdb_crypto *tc; 480 struct secasvar *sav; 481 struct secasindex *saidx; 482 caddr_t ptr; 483 484 crd = crp->crp_desc; 485 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!")); 486 487 tc = (struct tdb_crypto *) crp->crp_opaque; 488 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!")); 489 skip = tc->tc_skip; 490 protoff = tc->tc_protoff; 491 m = (struct mbuf *) crp->crp_buf; 492 493 sav = tc->tc_sav; 494 IPSEC_ASSERT(sav != NULL, ("null SA!")); 495 496 saidx = &sav->sah->saidx; 497 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 498 saidx->dst.sa.sa_family == AF_INET6, 499 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 500 501 esph = sav->tdb_authalgxform; 502 espx = sav->tdb_encalgxform; 503 504 /* Check for crypto errors */ 505 if (crp->crp_etype) { 506 /* Reset the session ID */ 507 if (sav->tdb_cryptoid != 0) 508 sav->tdb_cryptoid = crp->crp_sid; 509 510 if (crp->crp_etype == EAGAIN) 511 return (crypto_dispatch(crp)); 512 513 ESPSTAT_INC(esps_noxform); 514 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 515 error = crp->crp_etype; 516 goto bad; 517 } 518 519 /* Shouldn't happen... */ 520 if (m == NULL) { 521 ESPSTAT_INC(esps_crypto); 522 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 523 error = EINVAL; 524 goto bad; 525 } 526 ESPSTAT_INC(esps_hist[sav->alg_enc]); 527 528 /* If authentication was performed, check now. */ 529 if (esph != NULL) { 530 alen = xform_ah_authsize(esph); 531 AHSTAT_INC(ahs_hist[sav->alg_auth]); 532 /* Copy the authenticator from the packet */ 533 m_copydata(m, m->m_pkthdr.len - alen, alen, aalg); 534 ptr = (caddr_t) (tc + 1); 535 536 /* Verify authenticator */ 537 if (bcmp(ptr, aalg, alen) != 0) { 538 DPRINTF(("%s: authentication hash mismatch for " 539 "packet in SA %s/%08lx\n", __func__, 540 ipsec_address(&saidx->dst, buf, sizeof(buf)), 541 (u_long) ntohl(sav->spi))); 542 ESPSTAT_INC(esps_badauth); 543 error = EACCES; 544 goto bad; 545 } 546 547 /* Remove trailing authenticator */ 548 m_adj(m, -alen); 549 } 550 551 /* Release the crypto descriptors */ 552 free(tc, M_XDATA), tc = NULL; 553 crypto_freereq(crp), crp = NULL; 554 555 /* 556 * Packet is now decrypted. 557 */ 558 m->m_flags |= M_DECRYPTED; 559 560 /* 561 * Update replay sequence number, if appropriate. 562 */ 563 if (sav->replay) { 564 u_int32_t seq; 565 566 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 567 sizeof (seq), (caddr_t) &seq); 568 if (ipsec_updatereplay(ntohl(seq), sav)) { 569 DPRINTF(("%s: packet replay check for %s\n", __func__, 570 ipsec_logsastr(sav, buf, sizeof(buf)))); 571 ESPSTAT_INC(esps_replay); 572 error = ENOBUFS; 573 goto bad; 574 } 575 } 576 577 /* Determine the ESP header length */ 578 if (sav->flags & SADB_X_EXT_OLD) 579 hlen = sizeof (struct esp) + sav->ivlen; 580 else 581 hlen = sizeof (struct newesp) + sav->ivlen; 582 583 /* Remove the ESP header and IV from the mbuf. */ 584 error = m_striphdr(m, skip, hlen); 585 if (error) { 586 ESPSTAT_INC(esps_hdrops); 587 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 588 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 589 (u_long) ntohl(sav->spi))); 590 goto bad; 591 } 592 593 /* Save the last three bytes of decrypted data */ 594 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 595 596 /* Verify pad length */ 597 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 598 ESPSTAT_INC(esps_badilen); 599 DPRINTF(("%s: invalid padding length %d for %u byte packet " 600 "in SA %s/%08lx\n", __func__, lastthree[1], 601 m->m_pkthdr.len - skip, 602 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 603 (u_long) ntohl(sav->spi))); 604 error = EINVAL; 605 goto bad; 606 } 607 608 /* Verify correct decryption by checking the last padding bytes */ 609 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 610 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 611 ESPSTAT_INC(esps_badenc); 612 DPRINTF(("%s: decryption failed for packet in " 613 "SA %s/%08lx\n", __func__, ipsec_address( 614 &sav->sah->saidx.dst, buf, sizeof(buf)), 615 (u_long) ntohl(sav->spi))); 616 error = EINVAL; 617 goto bad; 618 } 619 } 620 621 /* Trim the mbuf chain to remove trailing authenticator and padding */ 622 m_adj(m, -(lastthree[1] + 2)); 623 624 /* Restore the Next Protocol field */ 625 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 626 627 switch (saidx->dst.sa.sa_family) { 628#ifdef INET6 629 case AF_INET6: 630 error = ipsec6_common_input_cb(m, sav, skip, protoff); 631 break; 632#endif 633#ifdef INET 634 case AF_INET: 635 error = ipsec4_common_input_cb(m, sav, skip, protoff); 636 break; 637#endif 638 default: 639 panic("%s: Unexpected address family: %d saidx=%p", __func__, 640 saidx->dst.sa.sa_family, saidx); 641 } 642 643 KEY_FREESAV(&sav); 644 return error; 645bad: 646 if (sav) 647 KEY_FREESAV(&sav); 648 if (m != NULL) 649 m_freem(m); 650 if (tc != NULL) 651 free(tc, M_XDATA); 652 if (crp != NULL) 653 crypto_freereq(crp); 654 return error; 655} 656 657/* 658 * ESP output routine, called by ipsec[46]_process_packet(). 659 */ 660static int 661esp_output(struct mbuf *m, struct ipsecrequest *isr, struct mbuf **mp, 662 int skip, int protoff) 663{ 664 char buf[INET6_ADDRSTRLEN]; 665 struct enc_xform *espx; 666 struct auth_hash *esph; 667 int hlen, rlen, padding, blks, alen, i, roff; 668 struct mbuf *mo = (struct mbuf *) NULL; 669 struct tdb_crypto *tc; 670 struct secasvar *sav; 671 struct secasindex *saidx; 672 unsigned char *pad; 673 u_int8_t prot; 674 int error, maxpacketsize; 675 676 struct cryptodesc *crde = NULL, *crda = NULL; 677 struct cryptop *crp; 678 679 sav = isr->sav; 680 IPSEC_ASSERT(sav != NULL, ("null SA")); 681 esph = sav->tdb_authalgxform; 682 espx = sav->tdb_encalgxform; 683 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 684 685 if (sav->flags & SADB_X_EXT_OLD) 686 hlen = sizeof (struct esp) + sav->ivlen; 687 else 688 hlen = sizeof (struct newesp) + sav->ivlen; 689 690 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 691 /* 692 * NB: The null encoding transform has a blocksize of 4 693 * so that headers are properly aligned. 694 */ 695 blks = espx->ivsize; /* IV blocksize */ 696 697 /* XXX clamp padding length a la KAME??? */ 698 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 699 700 alen = xform_ah_authsize(esph); 701 702 ESPSTAT_INC(esps_output); 703 704 saidx = &sav->sah->saidx; 705 /* Check for maximum packet size violations. */ 706 switch (saidx->dst.sa.sa_family) { 707#ifdef INET 708 case AF_INET: 709 maxpacketsize = IP_MAXPACKET; 710 break; 711#endif /* INET */ 712#ifdef INET6 713 case AF_INET6: 714 maxpacketsize = IPV6_MAXPACKET; 715 break; 716#endif /* INET6 */ 717 default: 718 DPRINTF(("%s: unknown/unsupported protocol " 719 "family %d, SA %s/%08lx\n", __func__, 720 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst, 721 buf, sizeof(buf)), (u_long) ntohl(sav->spi))); 722 ESPSTAT_INC(esps_nopf); 723 error = EPFNOSUPPORT; 724 goto bad; 725 } 726 DPRINTF(("%s: skip %d hlen %d rlen %d padding %d alen %d blksd %d\n", 727 __func__, skip, hlen, rlen, padding, alen, blks)); 728 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 729 DPRINTF(("%s: packet in SA %s/%08lx got too big " 730 "(len %u, max len %u)\n", __func__, 731 ipsec_address(&saidx->dst, buf, sizeof(buf)), 732 (u_long) ntohl(sav->spi), 733 skip + hlen + rlen + padding + alen, maxpacketsize)); 734 ESPSTAT_INC(esps_toobig); 735 error = EMSGSIZE; 736 goto bad; 737 } 738 739 /* Update the counters. */ 740 ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip); 741 742 m = m_unshare(m, M_NOWAIT); 743 if (m == NULL) { 744 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 745 ipsec_address(&saidx->dst, buf, sizeof(buf)), 746 (u_long) ntohl(sav->spi))); 747 ESPSTAT_INC(esps_hdrops); 748 error = ENOBUFS; 749 goto bad; 750 } 751 752 /* Inject ESP header. */ 753 mo = m_makespace(m, skip, hlen, &roff); 754 if (mo == NULL) { 755 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 756 __func__, hlen, ipsec_address(&saidx->dst, buf, 757 sizeof(buf)), (u_long) ntohl(sav->spi))); 758 ESPSTAT_INC(esps_hdrops); /* XXX diffs from openbsd */ 759 error = ENOBUFS; 760 goto bad; 761 } 762 763 /* Initialize ESP header. */ 764 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t)); 765 if (sav->replay) { 766 u_int32_t replay; 767 768#ifdef REGRESSION 769 /* Emulate replay attack when ipsec_replay is TRUE. */ 770 if (!V_ipsec_replay) 771#endif 772 sav->replay->count++; 773 replay = htonl(sav->replay->count); 774 bcopy((caddr_t) &replay, 775 mtod(mo, caddr_t) + roff + sizeof(u_int32_t), 776 sizeof(u_int32_t)); 777 } 778 779 /* 780 * Add padding -- better to do it ourselves than use the crypto engine, 781 * although if/when we support compression, we'd have to do that. 782 */ 783 pad = (u_char *) m_pad(m, padding + alen); 784 if (pad == NULL) { 785 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 786 ipsec_address(&saidx->dst, buf, sizeof(buf)), 787 (u_long) ntohl(sav->spi))); 788 m = NULL; /* NB: free'd by m_pad */ 789 error = ENOBUFS; 790 goto bad; 791 } 792 793 /* 794 * Add padding: random, zero, or self-describing. 795 * XXX catch unexpected setting 796 */ 797 switch (sav->flags & SADB_X_EXT_PMASK) { 798 case SADB_X_EXT_PRAND: 799 (void) read_random(pad, padding - 2); 800 break; 801 case SADB_X_EXT_PZERO: 802 bzero(pad, padding - 2); 803 break; 804 case SADB_X_EXT_PSEQ: 805 for (i = 0; i < padding - 2; i++) 806 pad[i] = i+1; 807 break; 808 } 809 810 /* Fix padding length and Next Protocol in padding itself. */ 811 pad[padding - 2] = padding - 2; 812 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 813 814 /* Fix Next Protocol in IPv4/IPv6 header. */ 815 prot = IPPROTO_ESP; 816 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 817 818 /* Get crypto descriptors. */ 819 crp = crypto_getreq(esph && espx ? 2 : 1); 820 if (crp == NULL) { 821 DPRINTF(("%s: failed to acquire crypto descriptors\n", 822 __func__)); 823 ESPSTAT_INC(esps_crypto); 824 error = ENOBUFS; 825 goto bad; 826 } 827 828 if (espx) { 829 crde = crp->crp_desc; 830 crda = crde->crd_next; 831 832 /* Encryption descriptor. */ 833 crde->crd_skip = skip + hlen; 834 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 835 crde->crd_flags = CRD_F_ENCRYPT; 836 crde->crd_inject = skip + hlen - sav->ivlen; 837 838 /* Encryption operation. */ 839 crde->crd_alg = espx->type; 840 crde->crd_key = sav->key_enc->key_data; 841 crde->crd_klen = _KEYBITS(sav->key_enc); 842 if (espx->type == CRYPTO_AES_NIST_GCM_16) 843 crde->crd_flags |= CRD_F_IV_EXPLICIT; 844 /* XXX Rounds ? */ 845 } else 846 crda = crp->crp_desc; 847 848 /* IPsec-specific opaque crypto info. */ 849 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 850 M_XDATA, M_NOWAIT|M_ZERO); 851 if (tc == NULL) { 852 crypto_freereq(crp); 853 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 854 ESPSTAT_INC(esps_crypto); 855 error = ENOBUFS; 856 goto bad; 857 } 858 859 /* Callback parameters */ 860 tc->tc_isr = isr; 861 KEY_ADDREFSA(sav); 862 tc->tc_sav = sav; 863 tc->tc_spi = sav->spi; 864 tc->tc_dst = saidx->dst; 865 tc->tc_proto = saidx->proto; 866 867 /* Crypto operation descriptor. */ 868 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 869 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 870 crp->crp_buf = (caddr_t) m; 871 crp->crp_callback = esp_output_cb; 872 crp->crp_opaque = (caddr_t) tc; 873 crp->crp_sid = sav->tdb_cryptoid; 874 875 if (esph) { 876 /* Authentication descriptor. */ 877 crda->crd_skip = skip; 878 if (espx && espx->type == CRYPTO_AES_NIST_GCM_16) 879 crda->crd_len = hlen - sav->ivlen; 880 else 881 crda->crd_len = m->m_pkthdr.len - (skip + alen); 882 crda->crd_inject = m->m_pkthdr.len - alen; 883 884 /* Authentication operation. */ 885 crda->crd_alg = esph->type; 886 if (espx && espx->type == CRYPTO_AES_NIST_GCM_16) { 887 crda->crd_key = sav->key_enc->key_data; 888 crda->crd_klen = _KEYBITS(sav->key_enc); 889 } else { 890 crda->crd_key = sav->key_auth->key_data; 891 crda->crd_klen = _KEYBITS(sav->key_auth); 892 } 893 894 } 895 896 return crypto_dispatch(crp); 897bad: 898 if (m) 899 m_freem(m); 900 return (error); 901} 902 903/* 904 * ESP output callback from the crypto driver. 905 */ 906static int 907esp_output_cb(struct cryptop *crp) 908{ 909 char buf[INET6_ADDRSTRLEN]; 910 struct tdb_crypto *tc; 911 struct ipsecrequest *isr; 912 struct secasvar *sav; 913 struct mbuf *m; 914 int error; 915 916 tc = (struct tdb_crypto *) crp->crp_opaque; 917 IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); 918 m = (struct mbuf *) crp->crp_buf; 919 920 isr = tc->tc_isr; 921 IPSEC_ASSERT(isr->sp != NULL, ("NULL isr->sp")); 922 IPSECREQUEST_LOCK(isr); 923 sav = tc->tc_sav; 924 /* With the isr lock released SA pointer can be updated. */ 925 if (sav != isr->sav) { 926 ESPSTAT_INC(esps_notdb); 927 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 928 __func__, ipsec_address(&tc->tc_dst, buf, sizeof(buf)), 929 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 930 error = ENOBUFS; /*XXX*/ 931 goto bad; 932 } 933 934 /* Check for crypto errors. */ 935 if (crp->crp_etype) { 936 /* Reset session ID. */ 937 if (sav->tdb_cryptoid != 0) 938 sav->tdb_cryptoid = crp->crp_sid; 939 940 if (crp->crp_etype == EAGAIN) { 941 IPSECREQUEST_UNLOCK(isr); 942 return (crypto_dispatch(crp)); 943 } 944 945 ESPSTAT_INC(esps_noxform); 946 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 947 error = crp->crp_etype; 948 goto bad; 949 } 950 951 /* Shouldn't happen... */ 952 if (m == NULL) { 953 ESPSTAT_INC(esps_crypto); 954 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 955 error = EINVAL; 956 goto bad; 957 } 958 ESPSTAT_INC(esps_hist[sav->alg_enc]); 959 if (sav->tdb_authalgxform != NULL) 960 AHSTAT_INC(ahs_hist[sav->alg_auth]); 961 962 /* Release crypto descriptors. */ 963 free(tc, M_XDATA); 964 crypto_freereq(crp); 965 966#ifdef REGRESSION 967 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 968 if (V_ipsec_integrity) { 969 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN]; 970 struct auth_hash *esph; 971 972 /* 973 * Corrupt HMAC if we want to test integrity verification of 974 * the other side. 975 */ 976 esph = sav->tdb_authalgxform; 977 if (esph != NULL) { 978 int alen; 979 980 alen = xform_ah_authsize(esph); 981 m_copyback(m, m->m_pkthdr.len - alen, 982 alen, ipseczeroes); 983 } 984 } 985#endif 986 987 /* NB: m is reclaimed by ipsec_process_done. */ 988 error = ipsec_process_done(m, isr); 989 KEY_FREESAV(&sav); 990 IPSECREQUEST_UNLOCK(isr); 991 KEY_FREESP(&isr->sp); 992 return (error); 993bad: 994 if (sav) 995 KEY_FREESAV(&sav); 996 IPSECREQUEST_UNLOCK(isr); 997 KEY_FREESP(&isr->sp); 998 if (m) 999 m_freem(m); 1000 free(tc, M_XDATA); 1001 crypto_freereq(crp); 1002 return (error); 1003} 1004 1005static struct xformsw esp_xformsw = { 1006 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 1007 esp_init, esp_zeroize, esp_input, 1008 esp_output 1009}; 1010 1011static void 1012esp_attach(void) 1013{ 1014 1015 xform_register(&esp_xformsw); 1016} 1017SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL); 1018