1 /* $FreeBSD$ */ 2 /* $OpenBSD: ip_esp.c,v 1.69 2001/06/26 06:18:59 angelos Exp $ */ 3 /*- 4 * The authors of this code are John Ioannidis (ji@tla.org), 5 * Angelos D. Keromytis (kermit@csd.uch.gr) and 6 * Niels Provos (provos@physnet.uni-hamburg.de). 7 * 8 * The original version of this code was written by John Ioannidis 9 * for BSD/OS in Athens, Greece, in November 1995. 10 * 11 * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996, 12 * by Angelos D. Keromytis. 13 * 14 * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis 15 * and Niels Provos. 16 * 17 * Additional features in 1999 by Angelos D. Keromytis. 18 * 19 * Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis, 20 * Angelos D. Keromytis and Niels Provos. 21 * Copyright (c) 2001 Angelos D. Keromytis. 22 * 23 * Permission to use, copy, and modify this software with or without fee 24 * is hereby granted, provided that this entire notice is included in 25 * all copies of any software which is or includes a copy or 26 * modification of this software. 27 * You may use this code under the GNU public license if you so wish. Please 28 * contribute changes back to the authors under this freer than GPL license 29 * so that we may further the use of strong encryption without limitations to 30 * all. 31 * 32 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR 33 * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY 34 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE 35 * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR 36 * PURPOSE. 37 */ 38 #include "opt_inet.h" 39 #include "opt_inet6.h" 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/mbuf.h> 44 #include <sys/socket.h> 45 #include <sys/syslog.h> 46 #include <sys/kernel.h> 47 #include <sys/lock.h> 48 #include <sys/random.h> 49 #include <sys/mutex.h> 50 #include <sys/sysctl.h> 51 #include <sys/mutex.h> 52 #include <machine/atomic.h> 53 54 #include <net/if.h> 55 #include <net/vnet.h> 56 57 #include <netinet/in.h> 58 #include <netinet/in_systm.h> 59 #include <netinet/ip.h> 60 #include <netinet/ip_ecn.h> 61 #include <netinet/ip6.h> 62 63 #include <netipsec/ipsec.h> 64 #include <netipsec/ah.h> 65 #include <netipsec/ah_var.h> 66 #include <netipsec/esp.h> 67 #include <netipsec/esp_var.h> 68 #include <netipsec/xform.h> 69 70 #ifdef INET6 71 #include <netinet6/ip6_var.h> 72 #include <netipsec/ipsec6.h> 73 #include <netinet6/ip6_ecn.h> 74 #endif 75 76 #include <netipsec/key.h> 77 #include <netipsec/key_debug.h> 78 79 #include <opencrypto/cryptodev.h> 80 #include <opencrypto/xform.h> 81 82 VNET_DEFINE(int, esp_enable) = 1; 83 VNET_PCPUSTAT_DEFINE(struct espstat, espstat); 84 VNET_PCPUSTAT_SYSINIT(espstat); 85 86 #ifdef VIMAGE 87 VNET_PCPUSTAT_SYSUNINIT(espstat); 88 #endif /* VIMAGE */ 89 90 SYSCTL_DECL(_net_inet_esp); 91 SYSCTL_INT(_net_inet_esp, OID_AUTO, esp_enable, 92 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(esp_enable), 0, ""); 93 SYSCTL_VNET_PCPUSTAT(_net_inet_esp, IPSECCTL_STATS, stats, 94 struct espstat, espstat, 95 "ESP statistics (struct espstat, netipsec/esp_var.h"); 96 97 static struct timeval deswarn, blfwarn, castwarn, camelliawarn; 98 99 static int esp_input_cb(struct cryptop *op); 100 static int esp_output_cb(struct cryptop *crp); 101 102 size_t 103 esp_hdrsiz(struct secasvar *sav) 104 { 105 size_t size; 106 107 if (sav != NULL) { 108 /*XXX not right for null algorithm--does it matter??*/ 109 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 110 ("SA with null xform")); 111 if (sav->flags & SADB_X_EXT_OLD) 112 size = sizeof (struct esp); 113 else 114 size = sizeof (struct newesp); 115 size += sav->tdb_encalgxform->blocksize + 9; 116 /*XXX need alg check???*/ 117 if (sav->tdb_authalgxform != NULL && sav->replay) 118 size += ah_hdrsiz(sav); 119 } else { 120 /* 121 * base header size 122 * + max iv length for CBC mode 123 * + max pad length 124 * + sizeof (pad length field) 125 * + sizeof (next header field) 126 * + max icv supported. 127 */ 128 size = sizeof (struct newesp) + EALG_MAX_BLOCK_LEN + 9 + 16; 129 } 130 return size; 131 } 132 133 /* 134 * esp_init() is called when an SPI is being set up. 135 */ 136 static int 137 esp_init(struct secasvar *sav, struct xformsw *xsp) 138 { 139 const struct enc_xform *txform; 140 struct cryptoini cria, crie; 141 int keylen; 142 int error; 143 144 txform = enc_algorithm_lookup(sav->alg_enc); 145 if (txform == NULL) { 146 DPRINTF(("%s: unsupported encryption algorithm %d\n", 147 __func__, sav->alg_enc)); 148 return EINVAL; 149 } 150 if (sav->key_enc == NULL) { 151 DPRINTF(("%s: no encoding key for %s algorithm\n", 152 __func__, txform->name)); 153 return EINVAL; 154 } 155 if ((sav->flags & (SADB_X_EXT_OLD | SADB_X_EXT_IV4B)) == 156 SADB_X_EXT_IV4B) { 157 DPRINTF(("%s: 4-byte IV not supported with protocol\n", 158 __func__)); 159 return EINVAL; 160 } 161 162 switch (sav->alg_enc) { 163 case SADB_EALG_DESCBC: 164 if (ratecheck(&deswarn, &ipsec_warn_interval)) 165 gone_in(13, "DES cipher for IPsec"); 166 break; 167 case SADB_X_EALG_BLOWFISHCBC: 168 if (ratecheck(&blfwarn, &ipsec_warn_interval)) 169 gone_in(13, "Blowfish cipher for IPsec"); 170 break; 171 case SADB_X_EALG_CAST128CBC: 172 if (ratecheck(&castwarn, &ipsec_warn_interval)) 173 gone_in(13, "CAST cipher for IPsec"); 174 break; 175 case SADB_X_EALG_CAMELLIACBC: 176 if (ratecheck(&camelliawarn, &ipsec_warn_interval)) 177 gone_in(13, "Camellia cipher for IPsec"); 178 break; 179 } 180 181 /* subtract off the salt, RFC4106, 8.1 and RFC3686, 5.1 */ 182 keylen = _KEYLEN(sav->key_enc) - SAV_ISCTRORGCM(sav) * 4; 183 if (txform->minkey > keylen || keylen > txform->maxkey) { 184 DPRINTF(("%s: invalid key length %u, must be in the range " 185 "[%u..%u] for algorithm %s\n", __func__, 186 keylen, txform->minkey, txform->maxkey, 187 txform->name)); 188 return EINVAL; 189 } 190 191 if (SAV_ISCTRORGCM(sav)) 192 sav->ivlen = 8; /* RFC4106 3.1 and RFC3686 3.1 */ 193 else 194 sav->ivlen = txform->ivsize; 195 196 /* 197 * Setup AH-related state. 198 */ 199 if (sav->alg_auth != 0) { 200 error = ah_init0(sav, xsp, &cria); 201 if (error) 202 return error; 203 } 204 205 /* NB: override anything set in ah_init0 */ 206 sav->tdb_xform = xsp; 207 sav->tdb_encalgxform = txform; 208 209 /* 210 * Whenever AES-GCM is used for encryption, one 211 * of the AES authentication algorithms is chosen 212 * as well, based on the key size. 213 */ 214 if (sav->alg_enc == SADB_X_EALG_AESGCM16) { 215 switch (keylen) { 216 case AES_128_GMAC_KEY_LEN: 217 sav->alg_auth = SADB_X_AALG_AES128GMAC; 218 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_128; 219 break; 220 case AES_192_GMAC_KEY_LEN: 221 sav->alg_auth = SADB_X_AALG_AES192GMAC; 222 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_192; 223 break; 224 case AES_256_GMAC_KEY_LEN: 225 sav->alg_auth = SADB_X_AALG_AES256GMAC; 226 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_256; 227 break; 228 default: 229 DPRINTF(("%s: invalid key length %u" 230 "for algorithm %s\n", __func__, 231 keylen, txform->name)); 232 return EINVAL; 233 } 234 bzero(&cria, sizeof(cria)); 235 cria.cri_alg = sav->tdb_authalgxform->type; 236 cria.cri_key = sav->key_enc->key_data; 237 cria.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISGCM(sav) * 32; 238 } 239 240 /* Initialize crypto session. */ 241 bzero(&crie, sizeof(crie)); 242 crie.cri_alg = sav->tdb_encalgxform->type; 243 crie.cri_key = sav->key_enc->key_data; 244 crie.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISCTRORGCM(sav) * 32; 245 246 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 247 /* init both auth & enc */ 248 crie.cri_next = &cria; 249 error = crypto_newsession(&sav->tdb_cryptoid, 250 &crie, V_crypto_support); 251 } else if (sav->tdb_encalgxform) { 252 error = crypto_newsession(&sav->tdb_cryptoid, 253 &crie, V_crypto_support); 254 } else if (sav->tdb_authalgxform) { 255 error = crypto_newsession(&sav->tdb_cryptoid, 256 &cria, V_crypto_support); 257 } else { 258 /* XXX cannot happen? */ 259 DPRINTF(("%s: no encoding OR authentication xform!\n", 260 __func__)); 261 error = EINVAL; 262 } 263 return error; 264 } 265 266 /* 267 * Paranoia. 268 */ 269 static int 270 esp_zeroize(struct secasvar *sav) 271 { 272 /* NB: ah_zerorize free's the crypto session state */ 273 int error = ah_zeroize(sav); 274 275 if (sav->key_enc) 276 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc)); 277 sav->tdb_encalgxform = NULL; 278 sav->tdb_xform = NULL; 279 return error; 280 } 281 282 /* 283 * ESP input processing, called (eventually) through the protocol switch. 284 */ 285 static int 286 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 287 { 288 IPSEC_DEBUG_DECLARE(char buf[128]); 289 const struct auth_hash *esph; 290 const struct enc_xform *espx; 291 struct xform_data *xd; 292 struct cryptodesc *crde; 293 struct cryptop *crp; 294 struct newesp *esp; 295 uint8_t *ivp; 296 crypto_session_t cryptoid; 297 int alen, error, hlen, plen; 298 299 IPSEC_ASSERT(sav != NULL, ("null SA")); 300 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); 301 302 error = EINVAL; 303 /* Valid IP Packet length ? */ 304 if ( (skip&3) || (m->m_pkthdr.len&3) ){ 305 DPRINTF(("%s: misaligned packet, skip %u pkt len %u", 306 __func__, skip, m->m_pkthdr.len)); 307 ESPSTAT_INC(esps_badilen); 308 goto bad; 309 } 310 311 if (m->m_len < skip + sizeof(*esp)) { 312 m = m_pullup(m, skip + sizeof(*esp)); 313 if (m == NULL) { 314 DPRINTF(("%s: cannot pullup header\n", __func__)); 315 ESPSTAT_INC(esps_hdrops); /*XXX*/ 316 error = ENOBUFS; 317 goto bad; 318 } 319 } 320 esp = (struct newesp *)(mtod(m, caddr_t) + skip); 321 322 esph = sav->tdb_authalgxform; 323 espx = sav->tdb_encalgxform; 324 325 /* Determine the ESP header and auth length */ 326 if (sav->flags & SADB_X_EXT_OLD) 327 hlen = sizeof (struct esp) + sav->ivlen; 328 else 329 hlen = sizeof (struct newesp) + sav->ivlen; 330 331 alen = xform_ah_authsize(esph); 332 333 /* 334 * Verify payload length is multiple of encryption algorithm 335 * block size. 336 * 337 * NB: This works for the null algorithm because the blocksize 338 * is 4 and all packets must be 4-byte aligned regardless 339 * of the algorithm. 340 */ 341 plen = m->m_pkthdr.len - (skip + hlen + alen); 342 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 343 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 344 " SA %s/%08lx\n", __func__, plen, espx->blocksize, 345 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 346 (u_long)ntohl(sav->spi))); 347 ESPSTAT_INC(esps_badilen); 348 goto bad; 349 } 350 351 /* 352 * Check sequence number. 353 */ 354 SECASVAR_LOCK(sav); 355 if (esph != NULL && sav->replay != NULL && sav->replay->wsize != 0) { 356 if (ipsec_chkreplay(ntohl(esp->esp_seq), sav) == 0) { 357 SECASVAR_UNLOCK(sav); 358 DPRINTF(("%s: packet replay check for %s\n", __func__, 359 ipsec_sa2str(sav, buf, sizeof(buf)))); 360 ESPSTAT_INC(esps_replay); 361 error = EACCES; 362 goto bad; 363 } 364 } 365 cryptoid = sav->tdb_cryptoid; 366 SECASVAR_UNLOCK(sav); 367 368 /* Update the counters */ 369 ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen)); 370 371 /* Get crypto descriptors */ 372 crp = crypto_getreq(esph && espx ? 2 : 1); 373 if (crp == NULL) { 374 DPRINTF(("%s: failed to acquire crypto descriptors\n", 375 __func__)); 376 ESPSTAT_INC(esps_crypto); 377 error = ENOBUFS; 378 goto bad; 379 } 380 381 /* Get IPsec-specific opaque pointer */ 382 xd = malloc(sizeof(*xd) + alen, M_XDATA, M_NOWAIT | M_ZERO); 383 if (xd == NULL) { 384 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 385 ESPSTAT_INC(esps_crypto); 386 crypto_freereq(crp); 387 error = ENOBUFS; 388 goto bad; 389 } 390 391 if (esph != NULL) { 392 struct cryptodesc *crda = crp->crp_desc; 393 394 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor")); 395 396 /* Authentication descriptor */ 397 crda->crd_skip = skip; 398 if (SAV_ISGCM(sav)) 399 crda->crd_len = 8; /* RFC4106 5, SPI + SN */ 400 else 401 crda->crd_len = m->m_pkthdr.len - (skip + alen); 402 crda->crd_inject = m->m_pkthdr.len - alen; 403 404 crda->crd_alg = esph->type; 405 406 /* Copy the authenticator */ 407 m_copydata(m, m->m_pkthdr.len - alen, alen, 408 (caddr_t) (xd + 1)); 409 410 /* Chain authentication request */ 411 crde = crda->crd_next; 412 } else { 413 crde = crp->crp_desc; 414 } 415 416 /* Crypto operation descriptor */ 417 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 418 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 419 if (V_async_crypto) 420 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 421 crp->crp_buf = (caddr_t) m; 422 crp->crp_callback = esp_input_cb; 423 crp->crp_session = cryptoid; 424 crp->crp_opaque = (caddr_t) xd; 425 426 /* These are passed as-is to the callback */ 427 xd->sav = sav; 428 xd->protoff = protoff; 429 xd->skip = skip; 430 xd->cryptoid = cryptoid; 431 xd->vnet = curvnet; 432 433 /* Decryption descriptor */ 434 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor")); 435 crde->crd_skip = skip + hlen; 436 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 437 crde->crd_inject = skip + hlen - sav->ivlen; 438 439 if (SAV_ISCTRORGCM(sav)) { 440 ivp = &crde->crd_iv[0]; 441 442 /* GCM IV Format: RFC4106 4 */ 443 /* CTR IV Format: RFC3686 4 */ 444 /* Salt is last four bytes of key, RFC4106 8.1 */ 445 /* Nonce is last four bytes of key, RFC3686 5.1 */ 446 memcpy(ivp, sav->key_enc->key_data + 447 _KEYLEN(sav->key_enc) - 4, 4); 448 449 if (SAV_ISCTR(sav)) { 450 /* Initial block counter is 1, RFC3686 4 */ 451 be32enc(&ivp[sav->ivlen + 4], 1); 452 } 453 454 m_copydata(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); 455 crde->crd_flags |= CRD_F_IV_EXPLICIT; 456 } 457 458 crde->crd_alg = espx->type; 459 460 return (crypto_dispatch(crp)); 461 bad: 462 m_freem(m); 463 key_freesav(&sav); 464 return (error); 465 } 466 467 /* 468 * ESP input callback from the crypto driver. 469 */ 470 static int 471 esp_input_cb(struct cryptop *crp) 472 { 473 IPSEC_DEBUG_DECLARE(char buf[128]); 474 u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN]; 475 const struct auth_hash *esph; 476 struct mbuf *m; 477 struct cryptodesc *crd; 478 struct xform_data *xd; 479 struct secasvar *sav; 480 struct secasindex *saidx; 481 caddr_t ptr; 482 crypto_session_t cryptoid; 483 int hlen, skip, protoff, error, alen; 484 485 crd = crp->crp_desc; 486 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!")); 487 488 m = (struct mbuf *) crp->crp_buf; 489 xd = (struct xform_data *) crp->crp_opaque; 490 CURVNET_SET(xd->vnet); 491 sav = xd->sav; 492 skip = xd->skip; 493 protoff = xd->protoff; 494 cryptoid = xd->cryptoid; 495 saidx = &sav->sah->saidx; 496 esph = sav->tdb_authalgxform; 497 498 /* Check for crypto errors */ 499 if (crp->crp_etype) { 500 if (crp->crp_etype == EAGAIN) { 501 /* Reset the session ID */ 502 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 503 crypto_freesession(cryptoid); 504 xd->cryptoid = crp->crp_session; 505 CURVNET_RESTORE(); 506 return (crypto_dispatch(crp)); 507 } 508 ESPSTAT_INC(esps_noxform); 509 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 510 error = crp->crp_etype; 511 goto bad; 512 } 513 514 /* Shouldn't happen... */ 515 if (m == NULL) { 516 ESPSTAT_INC(esps_crypto); 517 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 518 error = EINVAL; 519 goto bad; 520 } 521 ESPSTAT_INC(esps_hist[sav->alg_enc]); 522 523 /* If authentication was performed, check now. */ 524 if (esph != NULL) { 525 alen = xform_ah_authsize(esph); 526 AHSTAT_INC(ahs_hist[sav->alg_auth]); 527 /* Copy the authenticator from the packet */ 528 m_copydata(m, m->m_pkthdr.len - alen, alen, aalg); 529 ptr = (caddr_t) (xd + 1); 530 531 /* Verify authenticator */ 532 if (timingsafe_bcmp(ptr, aalg, alen) != 0) { 533 DPRINTF(("%s: authentication hash mismatch for " 534 "packet in SA %s/%08lx\n", __func__, 535 ipsec_address(&saidx->dst, buf, sizeof(buf)), 536 (u_long) ntohl(sav->spi))); 537 ESPSTAT_INC(esps_badauth); 538 error = EACCES; 539 goto bad; 540 } 541 m->m_flags |= M_AUTHIPDGM; 542 /* Remove trailing authenticator */ 543 m_adj(m, -alen); 544 } 545 546 /* Release the crypto descriptors */ 547 free(xd, M_XDATA), xd = NULL; 548 crypto_freereq(crp), crp = NULL; 549 550 /* 551 * Packet is now decrypted. 552 */ 553 m->m_flags |= M_DECRYPTED; 554 555 /* 556 * Update replay sequence number, if appropriate. 557 */ 558 if (sav->replay) { 559 u_int32_t seq; 560 561 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 562 sizeof (seq), (caddr_t) &seq); 563 SECASVAR_LOCK(sav); 564 if (ipsec_updatereplay(ntohl(seq), sav)) { 565 SECASVAR_UNLOCK(sav); 566 DPRINTF(("%s: packet replay check for %s\n", __func__, 567 ipsec_sa2str(sav, buf, sizeof(buf)))); 568 ESPSTAT_INC(esps_replay); 569 error = EACCES; 570 goto bad; 571 } 572 SECASVAR_UNLOCK(sav); 573 } 574 575 /* Determine the ESP header length */ 576 if (sav->flags & SADB_X_EXT_OLD) 577 hlen = sizeof (struct esp) + sav->ivlen; 578 else 579 hlen = sizeof (struct newesp) + sav->ivlen; 580 581 /* Remove the ESP header and IV from the mbuf. */ 582 error = m_striphdr(m, skip, hlen); 583 if (error) { 584 ESPSTAT_INC(esps_hdrops); 585 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 586 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 587 (u_long) ntohl(sav->spi))); 588 goto bad; 589 } 590 591 /* Save the last three bytes of decrypted data */ 592 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 593 594 /* Verify pad length */ 595 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 596 ESPSTAT_INC(esps_badilen); 597 DPRINTF(("%s: invalid padding length %d for %u byte packet " 598 "in SA %s/%08lx\n", __func__, lastthree[1], 599 m->m_pkthdr.len - skip, 600 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 601 (u_long) ntohl(sav->spi))); 602 error = EINVAL; 603 goto bad; 604 } 605 606 /* Verify correct decryption by checking the last padding bytes */ 607 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 608 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 609 ESPSTAT_INC(esps_badenc); 610 DPRINTF(("%s: decryption failed for packet in " 611 "SA %s/%08lx\n", __func__, ipsec_address( 612 &sav->sah->saidx.dst, buf, sizeof(buf)), 613 (u_long) ntohl(sav->spi))); 614 error = EINVAL; 615 goto bad; 616 } 617 } 618 619 /* 620 * RFC4303 2.6: 621 * Silently drop packet if next header field is IPPROTO_NONE. 622 */ 623 if (lastthree[2] == IPPROTO_NONE) 624 goto bad; 625 626 /* Trim the mbuf chain to remove trailing authenticator and padding */ 627 m_adj(m, -(lastthree[1] + 2)); 628 629 /* Restore the Next Protocol field */ 630 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 631 632 switch (saidx->dst.sa.sa_family) { 633 #ifdef INET6 634 case AF_INET6: 635 error = ipsec6_common_input_cb(m, sav, skip, protoff); 636 break; 637 #endif 638 #ifdef INET 639 case AF_INET: 640 error = ipsec4_common_input_cb(m, sav, skip, protoff); 641 break; 642 #endif 643 default: 644 panic("%s: Unexpected address family: %d saidx=%p", __func__, 645 saidx->dst.sa.sa_family, saidx); 646 } 647 CURVNET_RESTORE(); 648 return error; 649 bad: 650 CURVNET_RESTORE(); 651 if (sav != NULL) 652 key_freesav(&sav); 653 if (m != NULL) 654 m_freem(m); 655 if (xd != NULL) 656 free(xd, M_XDATA); 657 if (crp != NULL) 658 crypto_freereq(crp); 659 return error; 660 } 661 /* 662 * ESP output routine, called by ipsec[46]_perform_request(). 663 */ 664 static int 665 esp_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav, 666 u_int idx, int skip, int protoff) 667 { 668 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]); 669 struct cryptodesc *crde = NULL, *crda = NULL; 670 struct cryptop *crp; 671 const struct auth_hash *esph; 672 const struct enc_xform *espx; 673 struct mbuf *mo = NULL; 674 struct xform_data *xd; 675 struct secasindex *saidx; 676 unsigned char *pad; 677 uint8_t *ivp; 678 uint64_t cntr; 679 crypto_session_t cryptoid; 680 int hlen, rlen, padding, blks, alen, i, roff; 681 int error, maxpacketsize; 682 uint8_t prot; 683 684 IPSEC_ASSERT(sav != NULL, ("null SA")); 685 esph = sav->tdb_authalgxform; 686 espx = sav->tdb_encalgxform; 687 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 688 689 if (sav->flags & SADB_X_EXT_OLD) 690 hlen = sizeof (struct esp) + sav->ivlen; 691 else 692 hlen = sizeof (struct newesp) + sav->ivlen; 693 694 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 695 /* 696 * RFC4303 2.4 Requires 4 byte alignment. 697 */ 698 blks = MAX(4, espx->blocksize); /* Cipher blocksize */ 699 700 /* XXX clamp padding length a la KAME??? */ 701 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 702 703 alen = xform_ah_authsize(esph); 704 705 ESPSTAT_INC(esps_output); 706 707 saidx = &sav->sah->saidx; 708 /* Check for maximum packet size violations. */ 709 switch (saidx->dst.sa.sa_family) { 710 #ifdef INET 711 case AF_INET: 712 maxpacketsize = IP_MAXPACKET; 713 break; 714 #endif /* INET */ 715 #ifdef INET6 716 case AF_INET6: 717 maxpacketsize = IPV6_MAXPACKET; 718 break; 719 #endif /* INET6 */ 720 default: 721 DPRINTF(("%s: unknown/unsupported protocol " 722 "family %d, SA %s/%08lx\n", __func__, 723 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst, 724 buf, sizeof(buf)), (u_long) ntohl(sav->spi))); 725 ESPSTAT_INC(esps_nopf); 726 error = EPFNOSUPPORT; 727 goto bad; 728 } 729 /* 730 DPRINTF(("%s: skip %d hlen %d rlen %d padding %d alen %d blksd %d\n", 731 __func__, skip, hlen, rlen, padding, alen, blks)); */ 732 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 733 DPRINTF(("%s: packet in SA %s/%08lx got too big " 734 "(len %u, max len %u)\n", __func__, 735 ipsec_address(&saidx->dst, buf, sizeof(buf)), 736 (u_long) ntohl(sav->spi), 737 skip + hlen + rlen + padding + alen, maxpacketsize)); 738 ESPSTAT_INC(esps_toobig); 739 error = EMSGSIZE; 740 goto bad; 741 } 742 743 /* Update the counters. */ 744 ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip); 745 746 m = m_unshare(m, M_NOWAIT); 747 if (m == NULL) { 748 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 749 ipsec_address(&saidx->dst, buf, sizeof(buf)), 750 (u_long) ntohl(sav->spi))); 751 ESPSTAT_INC(esps_hdrops); 752 error = ENOBUFS; 753 goto bad; 754 } 755 756 /* Inject ESP header. */ 757 mo = m_makespace(m, skip, hlen, &roff); 758 if (mo == NULL) { 759 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 760 __func__, hlen, ipsec_address(&saidx->dst, buf, 761 sizeof(buf)), (u_long) ntohl(sav->spi))); 762 ESPSTAT_INC(esps_hdrops); /* XXX diffs from openbsd */ 763 error = ENOBUFS; 764 goto bad; 765 } 766 767 /* Initialize ESP header. */ 768 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, 769 sizeof(uint32_t)); 770 SECASVAR_LOCK(sav); 771 if (sav->replay) { 772 uint32_t replay; 773 774 #ifdef REGRESSION 775 /* Emulate replay attack when ipsec_replay is TRUE. */ 776 if (!V_ipsec_replay) 777 #endif 778 sav->replay->count++; 779 replay = htonl(sav->replay->count); 780 781 bcopy((caddr_t) &replay, mtod(mo, caddr_t) + roff + 782 sizeof(uint32_t), sizeof(uint32_t)); 783 } 784 cryptoid = sav->tdb_cryptoid; 785 if (SAV_ISCTRORGCM(sav)) 786 cntr = sav->cntr++; 787 SECASVAR_UNLOCK(sav); 788 789 /* 790 * Add padding -- better to do it ourselves than use the crypto engine, 791 * although if/when we support compression, we'd have to do that. 792 */ 793 pad = (u_char *) m_pad(m, padding + alen); 794 if (pad == NULL) { 795 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 796 ipsec_address(&saidx->dst, buf, sizeof(buf)), 797 (u_long) ntohl(sav->spi))); 798 m = NULL; /* NB: free'd by m_pad */ 799 error = ENOBUFS; 800 goto bad; 801 } 802 803 /* 804 * Add padding: random, zero, or self-describing. 805 * XXX catch unexpected setting 806 */ 807 switch (sav->flags & SADB_X_EXT_PMASK) { 808 case SADB_X_EXT_PRAND: 809 arc4random_buf(pad, padding - 2); 810 break; 811 case SADB_X_EXT_PZERO: 812 bzero(pad, padding - 2); 813 break; 814 case SADB_X_EXT_PSEQ: 815 for (i = 0; i < padding - 2; i++) 816 pad[i] = i+1; 817 break; 818 } 819 820 /* Fix padding length and Next Protocol in padding itself. */ 821 pad[padding - 2] = padding - 2; 822 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 823 824 /* Fix Next Protocol in IPv4/IPv6 header. */ 825 prot = IPPROTO_ESP; 826 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 827 828 /* Get crypto descriptors. */ 829 crp = crypto_getreq(esph != NULL ? 2 : 1); 830 if (crp == NULL) { 831 DPRINTF(("%s: failed to acquire crypto descriptors\n", 832 __func__)); 833 ESPSTAT_INC(esps_crypto); 834 error = ENOBUFS; 835 goto bad; 836 } 837 838 /* IPsec-specific opaque crypto info. */ 839 xd = malloc(sizeof(struct xform_data), M_XDATA, M_NOWAIT | M_ZERO); 840 if (xd == NULL) { 841 crypto_freereq(crp); 842 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 843 ESPSTAT_INC(esps_crypto); 844 error = ENOBUFS; 845 goto bad; 846 } 847 848 crde = crp->crp_desc; 849 crda = crde->crd_next; 850 851 /* Encryption descriptor. */ 852 crde->crd_skip = skip + hlen; 853 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 854 crde->crd_flags = CRD_F_ENCRYPT; 855 crde->crd_inject = skip + hlen - sav->ivlen; 856 857 /* Encryption operation. */ 858 crde->crd_alg = espx->type; 859 if (SAV_ISCTRORGCM(sav)) { 860 ivp = &crde->crd_iv[0]; 861 862 /* GCM IV Format: RFC4106 4 */ 863 /* CTR IV Format: RFC3686 4 */ 864 /* Salt is last four bytes of key, RFC4106 8.1 */ 865 /* Nonce is last four bytes of key, RFC3686 5.1 */ 866 memcpy(ivp, sav->key_enc->key_data + 867 _KEYLEN(sav->key_enc) - 4, 4); 868 be64enc(&ivp[4], cntr); 869 if (SAV_ISCTR(sav)) { 870 /* Initial block counter is 1, RFC3686 4 */ 871 /* XXXAE: should we use this only for first packet? */ 872 be32enc(&ivp[sav->ivlen + 4], 1); 873 } 874 875 m_copyback(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); 876 crde->crd_flags |= CRD_F_IV_EXPLICIT|CRD_F_IV_PRESENT; 877 } 878 879 /* Callback parameters */ 880 xd->sp = sp; 881 xd->sav = sav; 882 xd->idx = idx; 883 xd->cryptoid = cryptoid; 884 xd->vnet = curvnet; 885 886 /* Crypto operation descriptor. */ 887 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 888 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 889 if (V_async_crypto) 890 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 891 crp->crp_buf = (caddr_t) m; 892 crp->crp_callback = esp_output_cb; 893 crp->crp_opaque = (caddr_t) xd; 894 crp->crp_session = cryptoid; 895 896 if (esph) { 897 /* Authentication descriptor. */ 898 crda->crd_alg = esph->type; 899 crda->crd_skip = skip; 900 if (SAV_ISGCM(sav)) 901 crda->crd_len = 8; /* RFC4106 5, SPI + SN */ 902 else 903 crda->crd_len = m->m_pkthdr.len - (skip + alen); 904 crda->crd_inject = m->m_pkthdr.len - alen; 905 } 906 907 return crypto_dispatch(crp); 908 bad: 909 if (m) 910 m_freem(m); 911 key_freesav(&sav); 912 key_freesp(&sp); 913 return (error); 914 } 915 /* 916 * ESP output callback from the crypto driver. 917 */ 918 static int 919 esp_output_cb(struct cryptop *crp) 920 { 921 struct xform_data *xd; 922 struct secpolicy *sp; 923 struct secasvar *sav; 924 struct mbuf *m; 925 crypto_session_t cryptoid; 926 u_int idx; 927 int error; 928 929 xd = (struct xform_data *) crp->crp_opaque; 930 CURVNET_SET(xd->vnet); 931 m = (struct mbuf *) crp->crp_buf; 932 sp = xd->sp; 933 sav = xd->sav; 934 idx = xd->idx; 935 cryptoid = xd->cryptoid; 936 937 /* Check for crypto errors. */ 938 if (crp->crp_etype) { 939 if (crp->crp_etype == EAGAIN) { 940 /* Reset the session ID */ 941 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 942 crypto_freesession(cryptoid); 943 xd->cryptoid = crp->crp_session; 944 CURVNET_RESTORE(); 945 return (crypto_dispatch(crp)); 946 } 947 ESPSTAT_INC(esps_noxform); 948 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 949 error = crp->crp_etype; 950 m_freem(m); 951 goto bad; 952 } 953 954 /* Shouldn't happen... */ 955 if (m == NULL) { 956 ESPSTAT_INC(esps_crypto); 957 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 958 error = EINVAL; 959 goto bad; 960 } 961 free(xd, M_XDATA); 962 crypto_freereq(crp); 963 ESPSTAT_INC(esps_hist[sav->alg_enc]); 964 if (sav->tdb_authalgxform != NULL) 965 AHSTAT_INC(ahs_hist[sav->alg_auth]); 966 967 #ifdef REGRESSION 968 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 969 if (V_ipsec_integrity) { 970 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN]; 971 const struct auth_hash *esph; 972 973 /* 974 * Corrupt HMAC if we want to test integrity verification of 975 * the other side. 976 */ 977 esph = sav->tdb_authalgxform; 978 if (esph != NULL) { 979 int alen; 980 981 alen = xform_ah_authsize(esph); 982 m_copyback(m, m->m_pkthdr.len - alen, 983 alen, ipseczeroes); 984 } 985 } 986 #endif 987 988 /* NB: m is reclaimed by ipsec_process_done. */ 989 error = ipsec_process_done(m, sp, sav, idx); 990 CURVNET_RESTORE(); 991 return (error); 992 bad: 993 CURVNET_RESTORE(); 994 free(xd, M_XDATA); 995 crypto_freereq(crp); 996 key_freesav(&sav); 997 key_freesp(&sp); 998 return (error); 999 } 1000 1001 static struct xformsw esp_xformsw = { 1002 .xf_type = XF_ESP, 1003 .xf_name = "IPsec ESP", 1004 .xf_init = esp_init, 1005 .xf_zeroize = esp_zeroize, 1006 .xf_input = esp_input, 1007 .xf_output = esp_output, 1008 }; 1009 1010 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 1011 xform_attach, &esp_xformsw); 1012 SYSUNINIT(esp_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 1013 xform_detach, &esp_xformsw); 1014