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sys/netipsec/xform_esp.c
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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 #include "opt_ipsec.h" 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/mbuf.h> 45 #include <sys/socket.h> 46 #include <sys/syslog.h> 47 #include <sys/kernel.h> 48 #include <sys/lock.h> 49 #include <sys/random.h> 50 #include <sys/mutex.h> 51 #include <sys/sysctl.h> 52 #include <sys/mutex.h> 53 #include <machine/atomic.h> 54 55 #include <net/if.h> 56 #include <net/vnet.h> 57 58 #include <netinet/in.h> 59 #include <netinet/in_systm.h> 60 #include <netinet/ip.h> 61 #include <netinet/ip_ecn.h> 62 #include <netinet/ip6.h> 63 64 #include <netipsec/ipsec.h> 65 #include <netipsec/ah.h> 66 #include <netipsec/ah_var.h> 67 #include <netipsec/esp.h> 68 #include <netipsec/esp_var.h> 69 #include <netipsec/xform.h> 70 71 #ifdef INET6 72 #include <netinet6/ip6_var.h> 73 #include <netipsec/ipsec6.h> 74 #include <netinet6/ip6_ecn.h> 75 #endif 76 77 #include <netipsec/key.h> 78 #include <netipsec/key_debug.h> 79 80 #include <opencrypto/cryptodev.h> 81 #include <opencrypto/xform.h> 82 83 VNET_DEFINE(int, esp_enable) = 1; 84 VNET_PCPUSTAT_DEFINE(struct espstat, espstat); 85 VNET_PCPUSTAT_SYSINIT(espstat); 86 87 #ifdef VIMAGE 88 VNET_PCPUSTAT_SYSUNINIT(espstat); 89 #endif /* VIMAGE */ 90 91 SYSCTL_DECL(_net_inet_esp); 92 SYSCTL_INT(_net_inet_esp, OID_AUTO, esp_enable, 93 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(esp_enable), 0, ""); 94 SYSCTL_VNET_PCPUSTAT(_net_inet_esp, IPSECCTL_STATS, stats, 95 struct espstat, espstat, 96 "ESP statistics (struct espstat, netipsec/esp_var.h"); 97 98 static struct timeval deswarn, blfwarn, castwarn, camelliawarn, tdeswarn; 99 100 static int esp_input_cb(struct cryptop *op); 101 static int esp_output_cb(struct cryptop *crp); 102 103 size_t 104 esp_hdrsiz(struct secasvar *sav) 105 { 106 size_t size; 107 108 if (sav != NULL) { 109 /*XXX not right for null algorithm--does it matter??*/ 110 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 111 ("SA with null xform")); 112 if (sav->flags & SADB_X_EXT_OLD) 113 size = sizeof (struct esp); 114 else 115 size = sizeof (struct newesp); 116 size += sav->tdb_encalgxform->blocksize + 9; 117 /*XXX need alg check???*/ 118 if (sav->tdb_authalgxform != NULL && sav->replay) 119 size += ah_hdrsiz(sav); 120 } else { 121 /* 122 * base header size 123 * + max iv length for CBC mode 124 * + max pad length 125 * + sizeof (pad length field) 126 * + sizeof (next header field) 127 * + max icv supported. 128 */ 129 size = sizeof (struct newesp) + EALG_MAX_BLOCK_LEN + 9 + 16; 130 } 131 return size; 132 } 133 134 /* 135 * esp_init() is called when an SPI is being set up. 136 */ 137 static int 138 esp_init(struct secasvar *sav, struct xformsw *xsp) 139 { 140 const struct enc_xform *txform; 141 struct cryptoini cria, crie; 142 int keylen; 143 int error; 144 145 txform = enc_algorithm_lookup(sav->alg_enc); 146 if (txform == NULL) { 147 DPRINTF(("%s: unsupported encryption algorithm %d\n", 148 __func__, sav->alg_enc)); 149 return EINVAL; 150 } 151 if (sav->key_enc == NULL) { 152 DPRINTF(("%s: no encoding key for %s algorithm\n", 153 __func__, txform->name)); 154 return EINVAL; 155 } 156 if ((sav->flags & (SADB_X_EXT_OLD | SADB_X_EXT_IV4B)) == 157 SADB_X_EXT_IV4B) { 158 DPRINTF(("%s: 4-byte IV not supported with protocol\n", 159 __func__)); 160 return EINVAL; 161 } 162 163 switch (sav->alg_enc) { 164 case SADB_EALG_DESCBC: 165 if (ratecheck(&deswarn, &ipsec_warn_interval)) 166 gone_in(13, "DES cipher for IPsec"); 167 break; 168 case SADB_EALG_3DESCBC: 169 if (ratecheck(&tdeswarn, &ipsec_warn_interval)) 170 gone_in(13, "3DES cipher for IPsec"); 171 break; 172 case SADB_X_EALG_BLOWFISHCBC: 173 if (ratecheck(&blfwarn, &ipsec_warn_interval)) 174 gone_in(13, "Blowfish cipher for IPsec"); 175 break; 176 case SADB_X_EALG_CAST128CBC: 177 if (ratecheck(&castwarn, &ipsec_warn_interval)) 178 gone_in(13, "CAST cipher for IPsec"); 179 break; 180 case SADB_X_EALG_CAMELLIACBC: 181 if (ratecheck(&camelliawarn, &ipsec_warn_interval)) 182 gone_in(13, "Camellia cipher for IPsec"); 183 break; 184 } 185 186 /* subtract off the salt, RFC4106, 8.1 and RFC3686, 5.1 */ 187 keylen = _KEYLEN(sav->key_enc) - SAV_ISCTRORGCM(sav) * 4; 188 if (txform->minkey > keylen || keylen > txform->maxkey) { 189 DPRINTF(("%s: invalid key length %u, must be in the range " 190 "[%u..%u] for algorithm %s\n", __func__, 191 keylen, txform->minkey, txform->maxkey, 192 txform->name)); 193 return EINVAL; 194 } 195 196 if (SAV_ISCTRORGCM(sav)) 197 sav->ivlen = 8; /* RFC4106 3.1 and RFC3686 3.1 */ 198 else 199 sav->ivlen = txform->ivsize; 200 201 /* 202 * Setup AH-related state. 203 */ 204 if (sav->alg_auth != 0) { 205 error = ah_init0(sav, xsp, &cria); 206 if (error) 207 return error; 208 } 209 210 /* NB: override anything set in ah_init0 */ 211 sav->tdb_xform = xsp; 212 sav->tdb_encalgxform = txform; 213 214 /* 215 * Whenever AES-GCM is used for encryption, one 216 * of the AES authentication algorithms is chosen 217 * as well, based on the key size. 218 */ 219 if (sav->alg_enc == SADB_X_EALG_AESGCM16) { 220 switch (keylen) { 221 case AES_128_GMAC_KEY_LEN: 222 sav->alg_auth = SADB_X_AALG_AES128GMAC; 223 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_128; 224 break; 225 case AES_192_GMAC_KEY_LEN: 226 sav->alg_auth = SADB_X_AALG_AES192GMAC; 227 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_192; 228 break; 229 case AES_256_GMAC_KEY_LEN: 230 sav->alg_auth = SADB_X_AALG_AES256GMAC; 231 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_256; 232 break; 233 default: 234 DPRINTF(("%s: invalid key length %u" 235 "for algorithm %s\n", __func__, 236 keylen, txform->name)); 237 return EINVAL; 238 } 239 bzero(&cria, sizeof(cria)); 240 cria.cri_alg = sav->tdb_authalgxform->type; 241 cria.cri_key = sav->key_enc->key_data; 242 cria.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISGCM(sav) * 32; 243 } 244 245 /* Initialize crypto session. */ 246 bzero(&crie, sizeof(crie)); 247 crie.cri_alg = sav->tdb_encalgxform->type; 248 crie.cri_key = sav->key_enc->key_data; 249 crie.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISCTRORGCM(sav) * 32; 250 251 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 252 /* init both auth & enc */ 253 crie.cri_next = &cria; 254 error = crypto_newsession(&sav->tdb_cryptoid, 255 &crie, V_crypto_support); 256 } else if (sav->tdb_encalgxform) { 257 error = crypto_newsession(&sav->tdb_cryptoid, 258 &crie, V_crypto_support); 259 } else if (sav->tdb_authalgxform) { 260 error = crypto_newsession(&sav->tdb_cryptoid, 261 &cria, V_crypto_support); 262 } else { 263 /* XXX cannot happen? */ 264 DPRINTF(("%s: no encoding OR authentication xform!\n", 265 __func__)); 266 error = EINVAL; 267 } 268 return error; 269 } 270 271 /* 272 * Paranoia. 273 */ 274 static int 275 esp_zeroize(struct secasvar *sav) 276 { 277 /* NB: ah_zerorize free's the crypto session state */ 278 int error = ah_zeroize(sav); 279 280 if (sav->key_enc) 281 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc)); 282 sav->tdb_encalgxform = NULL; 283 sav->tdb_xform = NULL; 284 return error; 285 } 286 287 /* 288 * ESP input processing, called (eventually) through the protocol switch. 289 */ 290 static int 291 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 292 { 293 IPSEC_DEBUG_DECLARE(char buf[128]); 294 const struct auth_hash *esph; 295 const struct enc_xform *espx; 296 struct xform_data *xd; 297 struct cryptodesc *crde; 298 struct cryptop *crp; 299 struct newesp *esp; 300 uint8_t *ivp; 301 uint64_t cryptoid; 302 int alen, error, hlen, plen; 303 304 IPSEC_ASSERT(sav != NULL, ("null SA")); 305 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); 306 307 error = EINVAL; 308 /* Valid IP Packet length ? */ 309 if ( (skip&3) || (m->m_pkthdr.len&3) ){ 310 DPRINTF(("%s: misaligned packet, skip %u pkt len %u", 311 __func__, skip, m->m_pkthdr.len)); 312 ESPSTAT_INC(esps_badilen); 313 goto bad; 314 } 315 /* XXX don't pullup, just copy header */ 316 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 317 318 esph = sav->tdb_authalgxform; 319 espx = sav->tdb_encalgxform; 320 321 /* Determine the ESP header and auth length */ 322 if (sav->flags & SADB_X_EXT_OLD) 323 hlen = sizeof (struct esp) + sav->ivlen; 324 else 325 hlen = sizeof (struct newesp) + sav->ivlen; 326 327 alen = xform_ah_authsize(esph); 328 329 /* 330 * Verify payload length is multiple of encryption algorithm 331 * block size. 332 * 333 * NB: This works for the null algorithm because the blocksize 334 * is 4 and all packets must be 4-byte aligned regardless 335 * of the algorithm. 336 */ 337 plen = m->m_pkthdr.len - (skip + hlen + alen); 338 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 339 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 340 " SA %s/%08lx\n", __func__, plen, espx->blocksize, 341 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 342 (u_long)ntohl(sav->spi))); 343 ESPSTAT_INC(esps_badilen); 344 goto bad; 345 } 346 347 /* 348 * Check sequence number. 349 */ 350 SECASVAR_LOCK(sav); 351 if (esph != NULL && sav->replay != NULL && sav->replay->wsize != 0) { 352 if (ipsec_chkreplay(ntohl(esp->esp_seq), sav) == 0) { 353 SECASVAR_UNLOCK(sav); 354 DPRINTF(("%s: packet replay check for %s\n", __func__, 355 ipsec_sa2str(sav, buf, sizeof(buf)))); 356 ESPSTAT_INC(esps_replay); 357 error = EACCES; 358 goto bad; 359 } 360 } 361 cryptoid = sav->tdb_cryptoid; 362 SECASVAR_UNLOCK(sav); 363 364 /* Update the counters */ 365 ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen)); 366 367 /* Get crypto descriptors */ 368 crp = crypto_getreq(esph && espx ? 2 : 1); 369 if (crp == NULL) { 370 DPRINTF(("%s: failed to acquire crypto descriptors\n", 371 __func__)); 372 ESPSTAT_INC(esps_crypto); 373 error = ENOBUFS; 374 goto bad; 375 } 376 377 /* Get IPsec-specific opaque pointer */ 378 xd = malloc(sizeof(*xd) + alen, M_XDATA, M_NOWAIT | M_ZERO); 379 if (xd == NULL) { 380 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 381 ESPSTAT_INC(esps_crypto); 382 crypto_freereq(crp); 383 error = ENOBUFS; 384 goto bad; 385 } 386 387 if (esph != NULL) { 388 struct cryptodesc *crda = crp->crp_desc; 389 390 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor")); 391 392 /* Authentication descriptor */ 393 crda->crd_skip = skip; 394 if (SAV_ISGCM(sav)) 395 crda->crd_len = 8; /* RFC4106 5, SPI + SN */ 396 else 397 crda->crd_len = m->m_pkthdr.len - (skip + alen); 398 crda->crd_inject = m->m_pkthdr.len - alen; 399 400 crda->crd_alg = esph->type; 401 402 /* Copy the authenticator */ 403 m_copydata(m, m->m_pkthdr.len - alen, alen, 404 (caddr_t) (xd + 1)); 405 406 /* Chain authentication request */ 407 crde = crda->crd_next; 408 } else { 409 crde = crp->crp_desc; 410 } 411 412 /* Crypto operation descriptor */ 413 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 414 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 415 crp->crp_buf = (caddr_t) m; 416 crp->crp_callback = esp_input_cb; 417 crp->crp_sid = cryptoid; 418 crp->crp_opaque = (caddr_t) xd; 419 420 /* These are passed as-is to the callback */ 421 xd->sav = sav; 422 xd->protoff = protoff; 423 xd->skip = skip; 424 xd->cryptoid = cryptoid; 425 xd->vnet = curvnet; 426 427 /* Decryption descriptor */ 428 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor")); 429 crde->crd_skip = skip + hlen; 430 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 431 crde->crd_inject = skip + hlen - sav->ivlen; 432 433 if (SAV_ISCTRORGCM(sav)) { 434 ivp = &crde->crd_iv[0]; 435 436 /* GCM IV Format: RFC4106 4 */ 437 /* CTR IV Format: RFC3686 4 */ 438 /* Salt is last four bytes of key, RFC4106 8.1 */ 439 /* Nonce is last four bytes of key, RFC3686 5.1 */ 440 memcpy(ivp, sav->key_enc->key_data + 441 _KEYLEN(sav->key_enc) - 4, 4); 442 443 if (SAV_ISCTR(sav)) { 444 /* Initial block counter is 1, RFC3686 4 */ 445 be32enc(&ivp[sav->ivlen + 4], 1); 446 } 447 448 m_copydata(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); 449 crde->crd_flags |= CRD_F_IV_EXPLICIT; 450 } 451 452 crde->crd_alg = espx->type; 453 454 return (crypto_dispatch(crp)); 455 bad: 456 m_freem(m); 457 key_freesav(&sav); 458 return (error); 459 } 460 461 /* 462 * ESP input callback from the crypto driver. 463 */ 464 static int 465 esp_input_cb(struct cryptop *crp) 466 { 467 IPSEC_DEBUG_DECLARE(char buf[128]); 468 u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN]; 469 const struct auth_hash *esph; 470 const struct enc_xform *espx; 471 struct mbuf *m; 472 struct cryptodesc *crd; 473 struct xform_data *xd; 474 struct secasvar *sav; 475 struct secasindex *saidx; 476 caddr_t ptr; 477 uint64_t cryptoid; 478 int hlen, skip, protoff, error, alen; 479 480 crd = crp->crp_desc; 481 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!")); 482 483 m = (struct mbuf *) crp->crp_buf; 484 xd = (struct xform_data *) crp->crp_opaque; 485 CURVNET_SET(xd->vnet); 486 sav = xd->sav; 487 skip = xd->skip; 488 protoff = xd->protoff; 489 cryptoid = xd->cryptoid; 490 saidx = &sav->sah->saidx; 491 esph = sav->tdb_authalgxform; 492 espx = sav->tdb_encalgxform; 493 494 /* Check for crypto errors */ 495 if (crp->crp_etype) { 496 if (crp->crp_etype == EAGAIN) { 497 /* Reset the session ID */ 498 if (ipsec_updateid(sav, &crp->crp_sid, &cryptoid) != 0) 499 crypto_freesession(cryptoid); 500 xd->cryptoid = crp->crp_sid; 501 CURVNET_RESTORE(); 502 return (crypto_dispatch(crp)); 503 } 504 ESPSTAT_INC(esps_noxform); 505 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 506 error = crp->crp_etype; 507 goto bad; 508 } 509 510 /* Shouldn't happen... */ 511 if (m == NULL) { 512 ESPSTAT_INC(esps_crypto); 513 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 514 error = EINVAL; 515 goto bad; 516 } 517 ESPSTAT_INC(esps_hist[sav->alg_enc]); 518 519 /* If authentication was performed, check now. */ 520 if (esph != NULL) { 521 alen = xform_ah_authsize(esph); 522 AHSTAT_INC(ahs_hist[sav->alg_auth]); 523 /* Copy the authenticator from the packet */ 524 m_copydata(m, m->m_pkthdr.len - alen, alen, aalg); 525 ptr = (caddr_t) (xd + 1); 526 527 /* Verify authenticator */ 528 if (timingsafe_bcmp(ptr, aalg, alen) != 0) { 529 DPRINTF(("%s: authentication hash mismatch for " 530 "packet in SA %s/%08lx\n", __func__, 531 ipsec_address(&saidx->dst, buf, sizeof(buf)), 532 (u_long) ntohl(sav->spi))); 533 ESPSTAT_INC(esps_badauth); 534 error = EACCES; 535 goto bad; 536 } 537 m->m_flags |= M_AUTHIPDGM; 538 /* Remove trailing authenticator */ 539 m_adj(m, -alen); 540 } 541 542 /* Release the crypto descriptors */ 543 free(xd, M_XDATA), xd = NULL; 544 crypto_freereq(crp), crp = NULL; 545 546 /* 547 * Packet is now decrypted. 548 */ 549 m->m_flags |= M_DECRYPTED; 550 551 /* 552 * Update replay sequence number, if appropriate. 553 */ 554 if (sav->replay) { 555 u_int32_t seq; 556 557 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 558 sizeof (seq), (caddr_t) &seq); 559 SECASVAR_LOCK(sav); 560 if (ipsec_updatereplay(ntohl(seq), sav)) { 561 SECASVAR_UNLOCK(sav); 562 DPRINTF(("%s: packet replay check for %s\n", __func__, 563 ipsec_sa2str(sav, buf, sizeof(buf)))); 564 ESPSTAT_INC(esps_replay); 565 error = EACCES; 566 goto bad; 567 } 568 SECASVAR_UNLOCK(sav); 569 } 570 571 /* Determine the ESP header length */ 572 if (sav->flags & SADB_X_EXT_OLD) 573 hlen = sizeof (struct esp) + sav->ivlen; 574 else 575 hlen = sizeof (struct newesp) + sav->ivlen; 576 577 /* Remove the ESP header and IV from the mbuf. */ 578 error = m_striphdr(m, skip, hlen); 579 if (error) { 580 ESPSTAT_INC(esps_hdrops); 581 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 582 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 583 (u_long) ntohl(sav->spi))); 584 goto bad; 585 } 586 587 /* Save the last three bytes of decrypted data */ 588 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 589 590 /* Verify pad length */ 591 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 592 ESPSTAT_INC(esps_badilen); 593 DPRINTF(("%s: invalid padding length %d for %u byte packet " 594 "in SA %s/%08lx\n", __func__, lastthree[1], 595 m->m_pkthdr.len - skip, 596 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 597 (u_long) ntohl(sav->spi))); 598 error = EINVAL; 599 goto bad; 600 } 601 602 /* Verify correct decryption by checking the last padding bytes */ 603 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 604 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 605 ESPSTAT_INC(esps_badenc); 606 DPRINTF(("%s: decryption failed for packet in " 607 "SA %s/%08lx\n", __func__, ipsec_address( 608 &sav->sah->saidx.dst, buf, sizeof(buf)), 609 (u_long) ntohl(sav->spi))); 610 error = EINVAL; 611 goto bad; 612 } 613 } 614 615 /* 616 * RFC4303 2.6: 617 * Silently drop packet if next header field is IPPROTO_NONE. 618 */ 619 if (lastthree[2] == IPPROTO_NONE) 620 goto bad; 621 622 /* Trim the mbuf chain to remove trailing authenticator and padding */ 623 m_adj(m, -(lastthree[1] + 2)); 624 625 /* Restore the Next Protocol field */ 626 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 627 628 switch (saidx->dst.sa.sa_family) { 629 #ifdef INET6 630 case AF_INET6: 631 error = ipsec6_common_input_cb(m, sav, skip, protoff); 632 break; 633 #endif 634 #ifdef INET 635 case AF_INET: 636 error = ipsec4_common_input_cb(m, sav, skip, protoff); 637 break; 638 #endif 639 default: 640 panic("%s: Unexpected address family: %d saidx=%p", __func__, 641 saidx->dst.sa.sa_family, saidx); 642 } 643 CURVNET_RESTORE(); 644 return error; 645 bad: 646 CURVNET_RESTORE(); 647 if (sav != NULL) 648 key_freesav(&sav); 649 if (m != NULL) 650 m_freem(m); 651 if (xd != NULL) 652 free(xd, M_XDATA); 653 if (crp != NULL) 654 crypto_freereq(crp); 655 return error; 656 } 657 /* 658 * ESP output routine, called by ipsec[46]_perform_request(). 659 */ 660 static int 661 esp_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav, 662 u_int idx, int skip, int protoff) 663 { 664 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]); 665 struct cryptodesc *crde = NULL, *crda = NULL; 666 struct cryptop *crp; 667 const struct auth_hash *esph; 668 const struct enc_xform *espx; 669 struct mbuf *mo = NULL; 670 struct xform_data *xd; 671 struct secasindex *saidx; 672 unsigned char *pad; 673 uint8_t *ivp; 674 uint64_t cntr, cryptoid; 675 int hlen, rlen, padding, blks, alen, i, roff; 676 int error, maxpacketsize; 677 uint8_t prot; 678 679 IPSEC_ASSERT(sav != NULL, ("null SA")); 680 esph = sav->tdb_authalgxform; 681 espx = sav->tdb_encalgxform; 682 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 683 684 if (sav->flags & SADB_X_EXT_OLD) 685 hlen = sizeof (struct esp) + sav->ivlen; 686 else 687 hlen = sizeof (struct newesp) + sav->ivlen; 688 689 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 690 /* 691 * RFC4303 2.4 Requires 4 byte alignment. 692 */ 693 blks = MAX(4, espx->blocksize); /* Cipher blocksize */ 694 695 /* XXX clamp padding length a la KAME??? */ 696 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 697 698 alen = xform_ah_authsize(esph); 699 700 ESPSTAT_INC(esps_output); 701 702 saidx = &sav->sah->saidx; 703 /* Check for maximum packet size violations. */ 704 switch (saidx->dst.sa.sa_family) { 705 #ifdef INET 706 case AF_INET: 707 maxpacketsize = IP_MAXPACKET; 708 break; 709 #endif /* INET */ 710 #ifdef INET6 711 case AF_INET6: 712 maxpacketsize = IPV6_MAXPACKET; 713 break; 714 #endif /* INET6 */ 715 default: 716 DPRINTF(("%s: unknown/unsupported protocol " 717 "family %d, SA %s/%08lx\n", __func__, 718 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst, 719 buf, sizeof(buf)), (u_long) ntohl(sav->spi))); 720 ESPSTAT_INC(esps_nopf); 721 error = EPFNOSUPPORT; 722 goto bad; 723 } 724 /* 725 DPRINTF(("%s: skip %d hlen %d rlen %d padding %d alen %d blksd %d\n", 726 __func__, skip, hlen, rlen, padding, alen, blks)); */ 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, buf, sizeof(buf)), 731 (u_long) ntohl(sav->spi), 732 skip + hlen + rlen + padding + alen, maxpacketsize)); 733 ESPSTAT_INC(esps_toobig); 734 error = EMSGSIZE; 735 goto bad; 736 } 737 738 /* Update the counters. */ 739 ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip); 740 741 m = m_unshare(m, M_NOWAIT); 742 if (m == NULL) { 743 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 744 ipsec_address(&saidx->dst, buf, sizeof(buf)), 745 (u_long) ntohl(sav->spi))); 746 ESPSTAT_INC(esps_hdrops); 747 error = ENOBUFS; 748 goto bad; 749 } 750 751 /* Inject ESP header. */ 752 mo = m_makespace(m, skip, hlen, &roff); 753 if (mo == NULL) { 754 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 755 __func__, hlen, ipsec_address(&saidx->dst, buf, 756 sizeof(buf)), (u_long) ntohl(sav->spi))); 757 ESPSTAT_INC(esps_hdrops); /* XXX diffs from openbsd */ 758 error = ENOBUFS; 759 goto bad; 760 } 761 762 /* Initialize ESP header. */ 763 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, 764 sizeof(uint32_t)); 765 SECASVAR_LOCK(sav); 766 if (sav->replay) { 767 uint32_t replay; 768 769 #ifdef REGRESSION 770 /* Emulate replay attack when ipsec_replay is TRUE. */ 771 if (!V_ipsec_replay) 772 #endif 773 sav->replay->count++; 774 replay = htonl(sav->replay->count); 775 776 bcopy((caddr_t) &replay, mtod(mo, caddr_t) + roff + 777 sizeof(uint32_t), sizeof(uint32_t)); 778 } 779 cryptoid = sav->tdb_cryptoid; 780 if (SAV_ISCTRORGCM(sav)) 781 cntr = sav->cntr++; 782 SECASVAR_UNLOCK(sav); 783 784 /* 785 * Add padding -- better to do it ourselves than use the crypto engine, 786 * although if/when we support compression, we'd have to do that. 787 */ 788 pad = (u_char *) m_pad(m, padding + alen); 789 if (pad == NULL) { 790 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 791 ipsec_address(&saidx->dst, buf, sizeof(buf)), 792 (u_long) ntohl(sav->spi))); 793 m = NULL; /* NB: free'd by m_pad */ 794 error = ENOBUFS; 795 goto bad; 796 } 797 798 /* 799 * Add padding: random, zero, or self-describing. 800 * XXX catch unexpected setting 801 */ 802 switch (sav->flags & SADB_X_EXT_PMASK) { 803 case SADB_X_EXT_PRAND: 804 (void) read_random(pad, padding - 2); 805 break; 806 case SADB_X_EXT_PZERO: 807 bzero(pad, padding - 2); 808 break; 809 case SADB_X_EXT_PSEQ: 810 for (i = 0; i < padding - 2; i++) 811 pad[i] = i+1; 812 break; 813 } 814 815 /* Fix padding length and Next Protocol in padding itself. */ 816 pad[padding - 2] = padding - 2; 817 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 818 819 /* Fix Next Protocol in IPv4/IPv6 header. */ 820 prot = IPPROTO_ESP; 821 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 822 823 /* Get crypto descriptors. */ 824 crp = crypto_getreq(esph != NULL ? 2 : 1); 825 if (crp == NULL) { 826 DPRINTF(("%s: failed to acquire crypto descriptors\n", 827 __func__)); 828 ESPSTAT_INC(esps_crypto); 829 error = ENOBUFS; 830 goto bad; 831 } 832 833 /* IPsec-specific opaque crypto info. */ 834 xd = malloc(sizeof(struct xform_data), M_XDATA, M_NOWAIT | M_ZERO); 835 if (xd == NULL) { 836 crypto_freereq(crp); 837 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 838 ESPSTAT_INC(esps_crypto); 839 error = ENOBUFS; 840 goto bad; 841 } 842 843 crde = crp->crp_desc; 844 crda = crde->crd_next; 845 846 /* Encryption descriptor. */ 847 crde->crd_skip = skip + hlen; 848 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 849 crde->crd_flags = CRD_F_ENCRYPT; 850 crde->crd_inject = skip + hlen - sav->ivlen; 851 852 /* Encryption operation. */ 853 crde->crd_alg = espx->type; 854 if (SAV_ISCTRORGCM(sav)) { 855 ivp = &crde->crd_iv[0]; 856 857 /* GCM IV Format: RFC4106 4 */ 858 /* CTR IV Format: RFC3686 4 */ 859 /* Salt is last four bytes of key, RFC4106 8.1 */ 860 /* Nonce is last four bytes of key, RFC3686 5.1 */ 861 memcpy(ivp, sav->key_enc->key_data + 862 _KEYLEN(sav->key_enc) - 4, 4); 863 be64enc(&ivp[4], cntr); 864 if (SAV_ISCTR(sav)) { 865 /* Initial block counter is 1, RFC3686 4 */ 866 /* XXXAE: should we use this only for first packet? */ 867 be32enc(&ivp[sav->ivlen + 4], 1); 868 } 869 870 m_copyback(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); 871 crde->crd_flags |= CRD_F_IV_EXPLICIT|CRD_F_IV_PRESENT; 872 } 873 874 /* Callback parameters */ 875 xd->sp = sp; 876 xd->sav = sav; 877 xd->idx = idx; 878 xd->cryptoid = cryptoid; 879 xd->vnet = curvnet; 880 881 /* Crypto operation descriptor. */ 882 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 883 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 884 crp->crp_buf = (caddr_t) m; 885 crp->crp_callback = esp_output_cb; 886 crp->crp_opaque = (caddr_t) xd; 887 crp->crp_sid = cryptoid; 888 889 if (esph) { 890 /* Authentication descriptor. */ 891 crda->crd_alg = esph->type; 892 crda->crd_skip = skip; 893 if (SAV_ISGCM(sav)) 894 crda->crd_len = 8; /* RFC4106 5, SPI + SN */ 895 else 896 crda->crd_len = m->m_pkthdr.len - (skip + alen); 897 crda->crd_inject = m->m_pkthdr.len - alen; 898 } 899 900 return crypto_dispatch(crp); 901 bad: 902 if (m) 903 m_freem(m); 904 key_freesav(&sav); 905 key_freesp(&sp); 906 return (error); 907 } 908 /* 909 * ESP output callback from the crypto driver. 910 */ 911 static int 912 esp_output_cb(struct cryptop *crp) 913 { 914 struct xform_data *xd; 915 struct secpolicy *sp; 916 struct secasvar *sav; 917 struct mbuf *m; 918 uint64_t cryptoid; 919 u_int idx; 920 int error; 921 922 xd = (struct xform_data *) crp->crp_opaque; 923 CURVNET_SET(xd->vnet); 924 m = (struct mbuf *) crp->crp_buf; 925 sp = xd->sp; 926 sav = xd->sav; 927 idx = xd->idx; 928 cryptoid = xd->cryptoid; 929 930 /* Check for crypto errors. */ 931 if (crp->crp_etype) { 932 if (crp->crp_etype == EAGAIN) { 933 /* Reset the session ID */ 934 if (ipsec_updateid(sav, &crp->crp_sid, &cryptoid) != 0) 935 crypto_freesession(cryptoid); 936 xd->cryptoid = crp->crp_sid; 937 CURVNET_RESTORE(); 938 return (crypto_dispatch(crp)); 939 } 940 ESPSTAT_INC(esps_noxform); 941 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 942 error = crp->crp_etype; 943 m_freem(m); 944 goto bad; 945 } 946 947 /* Shouldn't happen... */ 948 if (m == NULL) { 949 ESPSTAT_INC(esps_crypto); 950 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 951 error = EINVAL; 952 goto bad; 953 } 954 free(xd, M_XDATA); 955 crypto_freereq(crp); 956 ESPSTAT_INC(esps_hist[sav->alg_enc]); 957 if (sav->tdb_authalgxform != NULL) 958 AHSTAT_INC(ahs_hist[sav->alg_auth]); 959 960 #ifdef REGRESSION 961 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 962 if (V_ipsec_integrity) { 963 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN]; 964 const struct auth_hash *esph; 965 966 /* 967 * Corrupt HMAC if we want to test integrity verification of 968 * the other side. 969 */ 970 esph = sav->tdb_authalgxform; 971 if (esph != NULL) { 972 int alen; 973 974 alen = xform_ah_authsize(esph); 975 m_copyback(m, m->m_pkthdr.len - alen, 976 alen, ipseczeroes); 977 } 978 } 979 #endif 980 981 /* NB: m is reclaimed by ipsec_process_done. */ 982 error = ipsec_process_done(m, sp, sav, idx); 983 CURVNET_RESTORE(); 984 return (error); 985 bad: 986 CURVNET_RESTORE(); 987 free(xd, M_XDATA); 988 crypto_freereq(crp); 989 key_freesav(&sav); 990 key_freesp(&sp); 991 return (error); 992 } 993 994 static struct xformsw esp_xformsw = { 995 .xf_type = XF_ESP, 996 .xf_name = "IPsec ESP", 997 .xf_init = esp_init, 998 .xf_zeroize = esp_zeroize, 999 .xf_input = esp_input, 1000 .xf_output = esp_output, 1001 }; 1002 1003 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 1004 xform_attach, &esp_xformsw); 1005 SYSUNINIT(esp_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 1006 xform_detach, &esp_xformsw);
Cache object: 1b0a7bdaed0d6c69f9d95bf4f18a7591
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