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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 crypto_session_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 } 315 316 if (m->m_len < skip + sizeof(*esp)) { 317 m = m_pullup(m, skip + sizeof(*esp)); 318 if (m == NULL) { 319 DPRINTF(("%s: cannot pullup header\n", __func__)); 320 ESPSTAT_INC(esps_hdrops); /*XXX*/ 321 error = ENOBUFS; 322 goto bad; 323 } 324 } 325 esp = (struct newesp *)(mtod(m, caddr_t) + skip); 326 327 esph = sav->tdb_authalgxform; 328 espx = sav->tdb_encalgxform; 329 330 /* Determine the ESP header and auth length */ 331 if (sav->flags & SADB_X_EXT_OLD) 332 hlen = sizeof (struct esp) + sav->ivlen; 333 else 334 hlen = sizeof (struct newesp) + sav->ivlen; 335 336 alen = xform_ah_authsize(esph); 337 338 /* 339 * Verify payload length is multiple of encryption algorithm 340 * block size. 341 * 342 * NB: This works for the null algorithm because the blocksize 343 * is 4 and all packets must be 4-byte aligned regardless 344 * of the algorithm. 345 */ 346 plen = m->m_pkthdr.len - (skip + hlen + alen); 347 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 348 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 349 " SA %s/%08lx\n", __func__, plen, espx->blocksize, 350 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 351 (u_long)ntohl(sav->spi))); 352 ESPSTAT_INC(esps_badilen); 353 goto bad; 354 } 355 356 /* 357 * Check sequence number. 358 */ 359 SECASVAR_LOCK(sav); 360 if (esph != NULL && sav->replay != NULL && sav->replay->wsize != 0) { 361 if (ipsec_chkreplay(ntohl(esp->esp_seq), sav) == 0) { 362 SECASVAR_UNLOCK(sav); 363 DPRINTF(("%s: packet replay check for %s\n", __func__, 364 ipsec_sa2str(sav, buf, sizeof(buf)))); 365 ESPSTAT_INC(esps_replay); 366 error = EACCES; 367 goto bad; 368 } 369 } 370 cryptoid = sav->tdb_cryptoid; 371 SECASVAR_UNLOCK(sav); 372 373 /* Update the counters */ 374 ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen)); 375 376 /* Get crypto descriptors */ 377 crp = crypto_getreq(esph && espx ? 2 : 1); 378 if (crp == NULL) { 379 DPRINTF(("%s: failed to acquire crypto descriptors\n", 380 __func__)); 381 ESPSTAT_INC(esps_crypto); 382 error = ENOBUFS; 383 goto bad; 384 } 385 386 /* Get IPsec-specific opaque pointer */ 387 xd = malloc(sizeof(*xd) + alen, M_XDATA, M_NOWAIT | M_ZERO); 388 if (xd == NULL) { 389 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 390 ESPSTAT_INC(esps_crypto); 391 crypto_freereq(crp); 392 error = ENOBUFS; 393 goto bad; 394 } 395 396 if (esph != NULL) { 397 struct cryptodesc *crda = crp->crp_desc; 398 399 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor")); 400 401 /* Authentication descriptor */ 402 crda->crd_skip = skip; 403 if (SAV_ISGCM(sav)) 404 crda->crd_len = 8; /* RFC4106 5, SPI + SN */ 405 else 406 crda->crd_len = m->m_pkthdr.len - (skip + alen); 407 crda->crd_inject = m->m_pkthdr.len - alen; 408 409 crda->crd_alg = esph->type; 410 411 /* Copy the authenticator */ 412 m_copydata(m, m->m_pkthdr.len - alen, alen, 413 (caddr_t) (xd + 1)); 414 415 /* Chain authentication request */ 416 crde = crda->crd_next; 417 } else { 418 crde = crp->crp_desc; 419 } 420 421 /* Crypto operation descriptor */ 422 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 423 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 424 if (V_async_crypto) 425 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 426 crp->crp_buf = (caddr_t) m; 427 crp->crp_callback = esp_input_cb; 428 crp->crp_session = cryptoid; 429 crp->crp_opaque = (caddr_t) xd; 430 431 /* These are passed as-is to the callback */ 432 xd->sav = sav; 433 xd->protoff = protoff; 434 xd->skip = skip; 435 xd->cryptoid = cryptoid; 436 xd->vnet = curvnet; 437 438 /* Decryption descriptor */ 439 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor")); 440 crde->crd_skip = skip + hlen; 441 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 442 crde->crd_inject = skip + hlen - sav->ivlen; 443 444 if (SAV_ISCTRORGCM(sav)) { 445 ivp = &crde->crd_iv[0]; 446 447 /* GCM IV Format: RFC4106 4 */ 448 /* CTR IV Format: RFC3686 4 */ 449 /* Salt is last four bytes of key, RFC4106 8.1 */ 450 /* Nonce is last four bytes of key, RFC3686 5.1 */ 451 memcpy(ivp, sav->key_enc->key_data + 452 _KEYLEN(sav->key_enc) - 4, 4); 453 454 if (SAV_ISCTR(sav)) { 455 /* Initial block counter is 1, RFC3686 4 */ 456 be32enc(&ivp[sav->ivlen + 4], 1); 457 } 458 459 m_copydata(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); 460 crde->crd_flags |= CRD_F_IV_EXPLICIT; 461 } 462 463 crde->crd_alg = espx->type; 464 465 return (crypto_dispatch(crp)); 466 bad: 467 m_freem(m); 468 key_freesav(&sav); 469 return (error); 470 } 471 472 /* 473 * ESP input callback from the crypto driver. 474 */ 475 static int 476 esp_input_cb(struct cryptop *crp) 477 { 478 IPSEC_DEBUG_DECLARE(char buf[128]); 479 u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN]; 480 const struct auth_hash *esph; 481 struct mbuf *m; 482 struct cryptodesc *crd; 483 struct xform_data *xd; 484 struct secasvar *sav; 485 struct secasindex *saidx; 486 caddr_t ptr; 487 crypto_session_t cryptoid; 488 int hlen, skip, protoff, error, alen; 489 490 crd = crp->crp_desc; 491 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!")); 492 493 m = (struct mbuf *) crp->crp_buf; 494 xd = (struct xform_data *) crp->crp_opaque; 495 CURVNET_SET(xd->vnet); 496 sav = xd->sav; 497 skip = xd->skip; 498 protoff = xd->protoff; 499 cryptoid = xd->cryptoid; 500 saidx = &sav->sah->saidx; 501 esph = sav->tdb_authalgxform; 502 503 /* Check for crypto errors */ 504 if (crp->crp_etype) { 505 if (crp->crp_etype == EAGAIN) { 506 /* Reset the session ID */ 507 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 508 crypto_freesession(cryptoid); 509 xd->cryptoid = crp->crp_session; 510 CURVNET_RESTORE(); 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) (xd + 1); 535 536 /* Verify authenticator */ 537 if (timingsafe_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 m->m_flags |= M_AUTHIPDGM; 547 /* Remove trailing authenticator */ 548 m_adj(m, -alen); 549 } 550 551 /* Release the crypto descriptors */ 552 free(xd, M_XDATA), xd = 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 SECASVAR_LOCK(sav); 569 if (ipsec_updatereplay(ntohl(seq), sav)) { 570 SECASVAR_UNLOCK(sav); 571 DPRINTF(("%s: packet replay check for %s\n", __func__, 572 ipsec_sa2str(sav, buf, sizeof(buf)))); 573 ESPSTAT_INC(esps_replay); 574 error = EACCES; 575 goto bad; 576 } 577 SECASVAR_UNLOCK(sav); 578 } 579 580 /* Determine the ESP header length */ 581 if (sav->flags & SADB_X_EXT_OLD) 582 hlen = sizeof (struct esp) + sav->ivlen; 583 else 584 hlen = sizeof (struct newesp) + sav->ivlen; 585 586 /* Remove the ESP header and IV from the mbuf. */ 587 error = m_striphdr(m, skip, hlen); 588 if (error) { 589 ESPSTAT_INC(esps_hdrops); 590 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 591 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 592 (u_long) ntohl(sav->spi))); 593 goto bad; 594 } 595 596 /* Save the last three bytes of decrypted data */ 597 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 598 599 /* Verify pad length */ 600 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 601 ESPSTAT_INC(esps_badilen); 602 DPRINTF(("%s: invalid padding length %d for %u byte packet " 603 "in SA %s/%08lx\n", __func__, lastthree[1], 604 m->m_pkthdr.len - skip, 605 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 606 (u_long) ntohl(sav->spi))); 607 error = EINVAL; 608 goto bad; 609 } 610 611 /* Verify correct decryption by checking the last padding bytes */ 612 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 613 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 614 ESPSTAT_INC(esps_badenc); 615 DPRINTF(("%s: decryption failed for packet in " 616 "SA %s/%08lx\n", __func__, ipsec_address( 617 &sav->sah->saidx.dst, buf, sizeof(buf)), 618 (u_long) ntohl(sav->spi))); 619 error = EINVAL; 620 goto bad; 621 } 622 } 623 624 /* 625 * RFC4303 2.6: 626 * Silently drop packet if next header field is IPPROTO_NONE. 627 */ 628 if (lastthree[2] == IPPROTO_NONE) 629 goto bad; 630 631 /* Trim the mbuf chain to remove trailing authenticator and padding */ 632 m_adj(m, -(lastthree[1] + 2)); 633 634 /* Restore the Next Protocol field */ 635 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 636 637 switch (saidx->dst.sa.sa_family) { 638 #ifdef INET6 639 case AF_INET6: 640 error = ipsec6_common_input_cb(m, sav, skip, protoff); 641 break; 642 #endif 643 #ifdef INET 644 case AF_INET: 645 error = ipsec4_common_input_cb(m, sav, skip, protoff); 646 break; 647 #endif 648 default: 649 panic("%s: Unexpected address family: %d saidx=%p", __func__, 650 saidx->dst.sa.sa_family, saidx); 651 } 652 CURVNET_RESTORE(); 653 return error; 654 bad: 655 CURVNET_RESTORE(); 656 if (sav != NULL) 657 key_freesav(&sav); 658 if (m != NULL) 659 m_freem(m); 660 if (xd != NULL) 661 free(xd, M_XDATA); 662 if (crp != NULL) 663 crypto_freereq(crp); 664 return error; 665 } 666 /* 667 * ESP output routine, called by ipsec[46]_perform_request(). 668 */ 669 static int 670 esp_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav, 671 u_int idx, int skip, int protoff) 672 { 673 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]); 674 struct cryptodesc *crde = NULL, *crda = NULL; 675 struct cryptop *crp; 676 const struct auth_hash *esph; 677 const struct enc_xform *espx; 678 struct mbuf *mo = NULL; 679 struct xform_data *xd; 680 struct secasindex *saidx; 681 unsigned char *pad; 682 uint8_t *ivp; 683 uint64_t cntr; 684 crypto_session_t cryptoid; 685 int hlen, rlen, padding, blks, alen, i, roff; 686 int error, maxpacketsize; 687 uint8_t prot; 688 689 IPSEC_ASSERT(sav != NULL, ("null SA")); 690 esph = sav->tdb_authalgxform; 691 espx = sav->tdb_encalgxform; 692 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 693 694 if (sav->flags & SADB_X_EXT_OLD) 695 hlen = sizeof (struct esp) + sav->ivlen; 696 else 697 hlen = sizeof (struct newesp) + sav->ivlen; 698 699 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 700 /* 701 * RFC4303 2.4 Requires 4 byte alignment. 702 */ 703 blks = MAX(4, espx->blocksize); /* Cipher blocksize */ 704 705 /* XXX clamp padding length a la KAME??? */ 706 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 707 708 alen = xform_ah_authsize(esph); 709 710 ESPSTAT_INC(esps_output); 711 712 saidx = &sav->sah->saidx; 713 /* Check for maximum packet size violations. */ 714 switch (saidx->dst.sa.sa_family) { 715 #ifdef INET 716 case AF_INET: 717 maxpacketsize = IP_MAXPACKET; 718 break; 719 #endif /* INET */ 720 #ifdef INET6 721 case AF_INET6: 722 maxpacketsize = IPV6_MAXPACKET; 723 break; 724 #endif /* INET6 */ 725 default: 726 DPRINTF(("%s: unknown/unsupported protocol " 727 "family %d, SA %s/%08lx\n", __func__, 728 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst, 729 buf, sizeof(buf)), (u_long) ntohl(sav->spi))); 730 ESPSTAT_INC(esps_nopf); 731 error = EPFNOSUPPORT; 732 goto bad; 733 } 734 /* 735 DPRINTF(("%s: skip %d hlen %d rlen %d padding %d alen %d blksd %d\n", 736 __func__, skip, hlen, rlen, padding, alen, blks)); */ 737 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 738 DPRINTF(("%s: packet in SA %s/%08lx got too big " 739 "(len %u, max len %u)\n", __func__, 740 ipsec_address(&saidx->dst, buf, sizeof(buf)), 741 (u_long) ntohl(sav->spi), 742 skip + hlen + rlen + padding + alen, maxpacketsize)); 743 ESPSTAT_INC(esps_toobig); 744 error = EMSGSIZE; 745 goto bad; 746 } 747 748 /* Update the counters. */ 749 ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip); 750 751 m = m_unshare(m, M_NOWAIT); 752 if (m == NULL) { 753 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 754 ipsec_address(&saidx->dst, buf, sizeof(buf)), 755 (u_long) ntohl(sav->spi))); 756 ESPSTAT_INC(esps_hdrops); 757 error = ENOBUFS; 758 goto bad; 759 } 760 761 /* Inject ESP header. */ 762 mo = m_makespace(m, skip, hlen, &roff); 763 if (mo == NULL) { 764 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 765 __func__, hlen, ipsec_address(&saidx->dst, buf, 766 sizeof(buf)), (u_long) ntohl(sav->spi))); 767 ESPSTAT_INC(esps_hdrops); /* XXX diffs from openbsd */ 768 error = ENOBUFS; 769 goto bad; 770 } 771 772 /* Initialize ESP header. */ 773 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, 774 sizeof(uint32_t)); 775 SECASVAR_LOCK(sav); 776 if (sav->replay) { 777 uint32_t replay; 778 779 #ifdef REGRESSION 780 /* Emulate replay attack when ipsec_replay is TRUE. */ 781 if (!V_ipsec_replay) 782 #endif 783 sav->replay->count++; 784 replay = htonl(sav->replay->count); 785 786 bcopy((caddr_t) &replay, mtod(mo, caddr_t) + roff + 787 sizeof(uint32_t), sizeof(uint32_t)); 788 } 789 cryptoid = sav->tdb_cryptoid; 790 if (SAV_ISCTRORGCM(sav)) 791 cntr = sav->cntr++; 792 SECASVAR_UNLOCK(sav); 793 794 /* 795 * Add padding -- better to do it ourselves than use the crypto engine, 796 * although if/when we support compression, we'd have to do that. 797 */ 798 pad = (u_char *) m_pad(m, padding + alen); 799 if (pad == NULL) { 800 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 801 ipsec_address(&saidx->dst, buf, sizeof(buf)), 802 (u_long) ntohl(sav->spi))); 803 m = NULL; /* NB: free'd by m_pad */ 804 error = ENOBUFS; 805 goto bad; 806 } 807 808 /* 809 * Add padding: random, zero, or self-describing. 810 * XXX catch unexpected setting 811 */ 812 switch (sav->flags & SADB_X_EXT_PMASK) { 813 case SADB_X_EXT_PRAND: 814 arc4random_buf(pad, padding - 2); 815 break; 816 case SADB_X_EXT_PZERO: 817 bzero(pad, padding - 2); 818 break; 819 case SADB_X_EXT_PSEQ: 820 for (i = 0; i < padding - 2; i++) 821 pad[i] = i+1; 822 break; 823 } 824 825 /* Fix padding length and Next Protocol in padding itself. */ 826 pad[padding - 2] = padding - 2; 827 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 828 829 /* Fix Next Protocol in IPv4/IPv6 header. */ 830 prot = IPPROTO_ESP; 831 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 832 833 /* Get crypto descriptors. */ 834 crp = crypto_getreq(esph != NULL ? 2 : 1); 835 if (crp == NULL) { 836 DPRINTF(("%s: failed to acquire crypto descriptors\n", 837 __func__)); 838 ESPSTAT_INC(esps_crypto); 839 error = ENOBUFS; 840 goto bad; 841 } 842 843 /* IPsec-specific opaque crypto info. */ 844 xd = malloc(sizeof(struct xform_data), M_XDATA, M_NOWAIT | M_ZERO); 845 if (xd == NULL) { 846 crypto_freereq(crp); 847 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 848 ESPSTAT_INC(esps_crypto); 849 error = ENOBUFS; 850 goto bad; 851 } 852 853 crde = crp->crp_desc; 854 crda = crde->crd_next; 855 856 /* Encryption descriptor. */ 857 crde->crd_skip = skip + hlen; 858 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 859 crde->crd_flags = CRD_F_ENCRYPT; 860 crde->crd_inject = skip + hlen - sav->ivlen; 861 862 /* Encryption operation. */ 863 crde->crd_alg = espx->type; 864 if (SAV_ISCTRORGCM(sav)) { 865 ivp = &crde->crd_iv[0]; 866 867 /* GCM IV Format: RFC4106 4 */ 868 /* CTR IV Format: RFC3686 4 */ 869 /* Salt is last four bytes of key, RFC4106 8.1 */ 870 /* Nonce is last four bytes of key, RFC3686 5.1 */ 871 memcpy(ivp, sav->key_enc->key_data + 872 _KEYLEN(sav->key_enc) - 4, 4); 873 be64enc(&ivp[4], cntr); 874 if (SAV_ISCTR(sav)) { 875 /* Initial block counter is 1, RFC3686 4 */ 876 /* XXXAE: should we use this only for first packet? */ 877 be32enc(&ivp[sav->ivlen + 4], 1); 878 } 879 880 m_copyback(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); 881 crde->crd_flags |= CRD_F_IV_EXPLICIT|CRD_F_IV_PRESENT; 882 } 883 884 /* Callback parameters */ 885 xd->sp = sp; 886 xd->sav = sav; 887 xd->idx = idx; 888 xd->cryptoid = cryptoid; 889 xd->vnet = curvnet; 890 891 /* Crypto operation descriptor. */ 892 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 893 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 894 if (V_async_crypto) 895 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 896 crp->crp_buf = (caddr_t) m; 897 crp->crp_callback = esp_output_cb; 898 crp->crp_opaque = (caddr_t) xd; 899 crp->crp_session = cryptoid; 900 901 if (esph) { 902 /* Authentication descriptor. */ 903 crda->crd_alg = esph->type; 904 crda->crd_skip = skip; 905 if (SAV_ISGCM(sav)) 906 crda->crd_len = 8; /* RFC4106 5, SPI + SN */ 907 else 908 crda->crd_len = m->m_pkthdr.len - (skip + alen); 909 crda->crd_inject = m->m_pkthdr.len - alen; 910 } 911 912 return crypto_dispatch(crp); 913 bad: 914 if (m) 915 m_freem(m); 916 key_freesav(&sav); 917 key_freesp(&sp); 918 return (error); 919 } 920 /* 921 * ESP output callback from the crypto driver. 922 */ 923 static int 924 esp_output_cb(struct cryptop *crp) 925 { 926 struct xform_data *xd; 927 struct secpolicy *sp; 928 struct secasvar *sav; 929 struct mbuf *m; 930 crypto_session_t cryptoid; 931 u_int idx; 932 int error; 933 934 xd = (struct xform_data *) crp->crp_opaque; 935 CURVNET_SET(xd->vnet); 936 m = (struct mbuf *) crp->crp_buf; 937 sp = xd->sp; 938 sav = xd->sav; 939 idx = xd->idx; 940 cryptoid = xd->cryptoid; 941 942 /* Check for crypto errors. */ 943 if (crp->crp_etype) { 944 if (crp->crp_etype == EAGAIN) { 945 /* Reset the session ID */ 946 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 947 crypto_freesession(cryptoid); 948 xd->cryptoid = crp->crp_session; 949 CURVNET_RESTORE(); 950 return (crypto_dispatch(crp)); 951 } 952 ESPSTAT_INC(esps_noxform); 953 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 954 error = crp->crp_etype; 955 m_freem(m); 956 goto bad; 957 } 958 959 /* Shouldn't happen... */ 960 if (m == NULL) { 961 ESPSTAT_INC(esps_crypto); 962 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 963 error = EINVAL; 964 goto bad; 965 } 966 free(xd, M_XDATA); 967 crypto_freereq(crp); 968 ESPSTAT_INC(esps_hist[sav->alg_enc]); 969 if (sav->tdb_authalgxform != NULL) 970 AHSTAT_INC(ahs_hist[sav->alg_auth]); 971 972 #ifdef REGRESSION 973 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 974 if (V_ipsec_integrity) { 975 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN]; 976 const struct auth_hash *esph; 977 978 /* 979 * Corrupt HMAC if we want to test integrity verification of 980 * the other side. 981 */ 982 esph = sav->tdb_authalgxform; 983 if (esph != NULL) { 984 int alen; 985 986 alen = xform_ah_authsize(esph); 987 m_copyback(m, m->m_pkthdr.len - alen, 988 alen, ipseczeroes); 989 } 990 } 991 #endif 992 993 /* NB: m is reclaimed by ipsec_process_done. */ 994 error = ipsec_process_done(m, sp, sav, idx); 995 CURVNET_RESTORE(); 996 return (error); 997 bad: 998 CURVNET_RESTORE(); 999 free(xd, M_XDATA); 1000 crypto_freereq(crp); 1001 key_freesav(&sav); 1002 key_freesp(&sp); 1003 return (error); 1004 } 1005 1006 static struct xformsw esp_xformsw = { 1007 .xf_type = XF_ESP, 1008 .xf_name = "IPsec ESP", 1009 .xf_init = esp_init, 1010 .xf_zeroize = esp_zeroize, 1011 .xf_input = esp_input, 1012 .xf_output = esp_output, 1013 }; 1014 1015 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 1016 xform_attach, &esp_xformsw); 1017 SYSUNINIT(esp_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 1018 xform_detach, &esp_xformsw);
Cache object: ec4198c2d82b6354bc7e956ac1b88444
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