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 /* XXX don't pullup, just copy header */ 311 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 312 313 esph = sav->tdb_authalgxform; 314 espx = sav->tdb_encalgxform; 315 316 /* Determine the ESP header and auth length */ 317 if (sav->flags & SADB_X_EXT_OLD) 318 hlen = sizeof (struct esp) + sav->ivlen; 319 else 320 hlen = sizeof (struct newesp) + sav->ivlen; 321 322 alen = xform_ah_authsize(esph); 323 324 /* 325 * Verify payload length is multiple of encryption algorithm 326 * block size. 327 * 328 * NB: This works for the null algorithm because the blocksize 329 * is 4 and all packets must be 4-byte aligned regardless 330 * of the algorithm. 331 */ 332 plen = m->m_pkthdr.len - (skip + hlen + alen); 333 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 334 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 335 " SA %s/%08lx\n", __func__, plen, espx->blocksize, 336 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 337 (u_long)ntohl(sav->spi))); 338 ESPSTAT_INC(esps_badilen); 339 goto bad; 340 } 341 342 /* 343 * Check sequence number. 344 */ 345 SECASVAR_LOCK(sav); 346 if (esph != NULL && sav->replay != NULL && sav->replay->wsize != 0) { 347 if (ipsec_chkreplay(ntohl(esp->esp_seq), sav) == 0) { 348 SECASVAR_UNLOCK(sav); 349 DPRINTF(("%s: packet replay check for %s\n", __func__, 350 ipsec_sa2str(sav, buf, sizeof(buf)))); 351 ESPSTAT_INC(esps_replay); 352 error = EACCES; 353 goto bad; 354 } 355 } 356 cryptoid = sav->tdb_cryptoid; 357 SECASVAR_UNLOCK(sav); 358 359 /* Update the counters */ 360 ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen)); 361 362 /* Get crypto descriptors */ 363 crp = crypto_getreq(esph && espx ? 2 : 1); 364 if (crp == NULL) { 365 DPRINTF(("%s: failed to acquire crypto descriptors\n", 366 __func__)); 367 ESPSTAT_INC(esps_crypto); 368 error = ENOBUFS; 369 goto bad; 370 } 371 372 /* Get IPsec-specific opaque pointer */ 373 xd = malloc(sizeof(*xd) + alen, M_XDATA, M_NOWAIT | M_ZERO); 374 if (xd == NULL) { 375 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 376 ESPSTAT_INC(esps_crypto); 377 crypto_freereq(crp); 378 error = ENOBUFS; 379 goto bad; 380 } 381 382 if (esph != NULL) { 383 struct cryptodesc *crda = crp->crp_desc; 384 385 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor")); 386 387 /* Authentication descriptor */ 388 crda->crd_skip = skip; 389 if (SAV_ISGCM(sav)) 390 crda->crd_len = 8; /* RFC4106 5, SPI + SN */ 391 else 392 crda->crd_len = m->m_pkthdr.len - (skip + alen); 393 crda->crd_inject = m->m_pkthdr.len - alen; 394 395 crda->crd_alg = esph->type; 396 397 /* Copy the authenticator */ 398 m_copydata(m, m->m_pkthdr.len - alen, alen, 399 (caddr_t) (xd + 1)); 400 401 /* Chain authentication request */ 402 crde = crda->crd_next; 403 } else { 404 crde = crp->crp_desc; 405 } 406 407 /* Crypto operation descriptor */ 408 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 409 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 410 if (V_async_crypto) 411 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 412 crp->crp_buf = (caddr_t) m; 413 crp->crp_callback = esp_input_cb; 414 crp->crp_session = cryptoid; 415 crp->crp_opaque = (caddr_t) xd; 416 417 /* These are passed as-is to the callback */ 418 xd->sav = sav; 419 xd->protoff = protoff; 420 xd->skip = skip; 421 xd->cryptoid = cryptoid; 422 xd->vnet = curvnet; 423 424 /* Decryption descriptor */ 425 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor")); 426 crde->crd_skip = skip + hlen; 427 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 428 crde->crd_inject = skip + hlen - sav->ivlen; 429 430 if (SAV_ISCTRORGCM(sav)) { 431 ivp = &crde->crd_iv[0]; 432 433 /* GCM IV Format: RFC4106 4 */ 434 /* CTR IV Format: RFC3686 4 */ 435 /* Salt is last four bytes of key, RFC4106 8.1 */ 436 /* Nonce is last four bytes of key, RFC3686 5.1 */ 437 memcpy(ivp, sav->key_enc->key_data + 438 _KEYLEN(sav->key_enc) - 4, 4); 439 440 if (SAV_ISCTR(sav)) { 441 /* Initial block counter is 1, RFC3686 4 */ 442 be32enc(&ivp[sav->ivlen + 4], 1); 443 } 444 445 m_copydata(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); 446 crde->crd_flags |= CRD_F_IV_EXPLICIT; 447 } 448 449 crde->crd_alg = espx->type; 450 451 return (crypto_dispatch(crp)); 452 bad: 453 m_freem(m); 454 key_freesav(&sav); 455 return (error); 456 } 457 458 /* 459 * ESP input callback from the crypto driver. 460 */ 461 static int 462 esp_input_cb(struct cryptop *crp) 463 { 464 IPSEC_DEBUG_DECLARE(char buf[128]); 465 u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN]; 466 const struct auth_hash *esph; 467 struct mbuf *m; 468 struct cryptodesc *crd; 469 struct xform_data *xd; 470 struct secasvar *sav; 471 struct secasindex *saidx; 472 caddr_t ptr; 473 crypto_session_t cryptoid; 474 int hlen, skip, protoff, error, alen; 475 476 crd = crp->crp_desc; 477 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!")); 478 479 m = (struct mbuf *) crp->crp_buf; 480 xd = (struct xform_data *) crp->crp_opaque; 481 CURVNET_SET(xd->vnet); 482 sav = xd->sav; 483 skip = xd->skip; 484 protoff = xd->protoff; 485 cryptoid = xd->cryptoid; 486 saidx = &sav->sah->saidx; 487 esph = sav->tdb_authalgxform; 488 489 /* Check for crypto errors */ 490 if (crp->crp_etype) { 491 if (crp->crp_etype == EAGAIN) { 492 /* Reset the session ID */ 493 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 494 crypto_freesession(cryptoid); 495 xd->cryptoid = crp->crp_session; 496 CURVNET_RESTORE(); 497 return (crypto_dispatch(crp)); 498 } 499 ESPSTAT_INC(esps_noxform); 500 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 501 error = crp->crp_etype; 502 goto bad; 503 } 504 505 /* Shouldn't happen... */ 506 if (m == NULL) { 507 ESPSTAT_INC(esps_crypto); 508 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 509 error = EINVAL; 510 goto bad; 511 } 512 ESPSTAT_INC(esps_hist[sav->alg_enc]); 513 514 /* If authentication was performed, check now. */ 515 if (esph != NULL) { 516 alen = xform_ah_authsize(esph); 517 AHSTAT_INC(ahs_hist[sav->alg_auth]); 518 /* Copy the authenticator from the packet */ 519 m_copydata(m, m->m_pkthdr.len - alen, alen, aalg); 520 ptr = (caddr_t) (xd + 1); 521 522 /* Verify authenticator */ 523 if (timingsafe_bcmp(ptr, aalg, alen) != 0) { 524 DPRINTF(("%s: authentication hash mismatch for " 525 "packet in SA %s/%08lx\n", __func__, 526 ipsec_address(&saidx->dst, buf, sizeof(buf)), 527 (u_long) ntohl(sav->spi))); 528 ESPSTAT_INC(esps_badauth); 529 error = EACCES; 530 goto bad; 531 } 532 m->m_flags |= M_AUTHIPDGM; 533 /* Remove trailing authenticator */ 534 m_adj(m, -alen); 535 } 536 537 /* Release the crypto descriptors */ 538 free(xd, M_XDATA), xd = NULL; 539 crypto_freereq(crp), crp = NULL; 540 541 /* 542 * Packet is now decrypted. 543 */ 544 m->m_flags |= M_DECRYPTED; 545 546 /* 547 * Update replay sequence number, if appropriate. 548 */ 549 if (sav->replay) { 550 u_int32_t seq; 551 552 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 553 sizeof (seq), (caddr_t) &seq); 554 SECASVAR_LOCK(sav); 555 if (ipsec_updatereplay(ntohl(seq), sav)) { 556 SECASVAR_UNLOCK(sav); 557 DPRINTF(("%s: packet replay check for %s\n", __func__, 558 ipsec_sa2str(sav, buf, sizeof(buf)))); 559 ESPSTAT_INC(esps_replay); 560 error = EACCES; 561 goto bad; 562 } 563 SECASVAR_UNLOCK(sav); 564 } 565 566 /* Determine the ESP header length */ 567 if (sav->flags & SADB_X_EXT_OLD) 568 hlen = sizeof (struct esp) + sav->ivlen; 569 else 570 hlen = sizeof (struct newesp) + sav->ivlen; 571 572 /* Remove the ESP header and IV from the mbuf. */ 573 error = m_striphdr(m, skip, hlen); 574 if (error) { 575 ESPSTAT_INC(esps_hdrops); 576 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 577 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 578 (u_long) ntohl(sav->spi))); 579 goto bad; 580 } 581 582 /* Save the last three bytes of decrypted data */ 583 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 584 585 /* Verify pad length */ 586 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 587 ESPSTAT_INC(esps_badilen); 588 DPRINTF(("%s: invalid padding length %d for %u byte packet " 589 "in SA %s/%08lx\n", __func__, lastthree[1], 590 m->m_pkthdr.len - skip, 591 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 592 (u_long) ntohl(sav->spi))); 593 error = EINVAL; 594 goto bad; 595 } 596 597 /* Verify correct decryption by checking the last padding bytes */ 598 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 599 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 600 ESPSTAT_INC(esps_badenc); 601 DPRINTF(("%s: decryption failed for packet in " 602 "SA %s/%08lx\n", __func__, ipsec_address( 603 &sav->sah->saidx.dst, buf, sizeof(buf)), 604 (u_long) ntohl(sav->spi))); 605 error = EINVAL; 606 goto bad; 607 } 608 } 609 610 /* Trim the mbuf chain to remove trailing authenticator and padding */ 611 m_adj(m, -(lastthree[1] + 2)); 612 613 /* Restore the Next Protocol field */ 614 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 615 616 switch (saidx->dst.sa.sa_family) { 617 #ifdef INET6 618 case AF_INET6: 619 error = ipsec6_common_input_cb(m, sav, skip, protoff); 620 break; 621 #endif 622 #ifdef INET 623 case AF_INET: 624 error = ipsec4_common_input_cb(m, sav, skip, protoff); 625 break; 626 #endif 627 default: 628 panic("%s: Unexpected address family: %d saidx=%p", __func__, 629 saidx->dst.sa.sa_family, saidx); 630 } 631 CURVNET_RESTORE(); 632 return error; 633 bad: 634 CURVNET_RESTORE(); 635 if (sav != NULL) 636 key_freesav(&sav); 637 if (m != NULL) 638 m_freem(m); 639 if (xd != NULL) 640 free(xd, M_XDATA); 641 if (crp != NULL) 642 crypto_freereq(crp); 643 return error; 644 } 645 /* 646 * ESP output routine, called by ipsec[46]_perform_request(). 647 */ 648 static int 649 esp_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav, 650 u_int idx, int skip, int protoff) 651 { 652 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]); 653 struct cryptodesc *crde = NULL, *crda = NULL; 654 struct cryptop *crp; 655 const struct auth_hash *esph; 656 const struct enc_xform *espx; 657 struct mbuf *mo = NULL; 658 struct xform_data *xd; 659 struct secasindex *saidx; 660 unsigned char *pad; 661 uint8_t *ivp; 662 uint64_t cntr; 663 crypto_session_t cryptoid; 664 int hlen, rlen, padding, blks, alen, i, roff; 665 int error, maxpacketsize; 666 uint8_t prot; 667 668 IPSEC_ASSERT(sav != NULL, ("null SA")); 669 esph = sav->tdb_authalgxform; 670 espx = sav->tdb_encalgxform; 671 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 672 673 if (sav->flags & SADB_X_EXT_OLD) 674 hlen = sizeof (struct esp) + sav->ivlen; 675 else 676 hlen = sizeof (struct newesp) + sav->ivlen; 677 678 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 679 /* 680 * RFC4303 2.4 Requires 4 byte alignment. 681 */ 682 blks = MAX(4, espx->blocksize); /* Cipher blocksize */ 683 684 /* XXX clamp padding length a la KAME??? */ 685 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 686 687 alen = xform_ah_authsize(esph); 688 689 ESPSTAT_INC(esps_output); 690 691 saidx = &sav->sah->saidx; 692 /* Check for maximum packet size violations. */ 693 switch (saidx->dst.sa.sa_family) { 694 #ifdef INET 695 case AF_INET: 696 maxpacketsize = IP_MAXPACKET; 697 break; 698 #endif /* INET */ 699 #ifdef INET6 700 case AF_INET6: 701 maxpacketsize = IPV6_MAXPACKET; 702 break; 703 #endif /* INET6 */ 704 default: 705 DPRINTF(("%s: unknown/unsupported protocol " 706 "family %d, SA %s/%08lx\n", __func__, 707 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst, 708 buf, sizeof(buf)), (u_long) ntohl(sav->spi))); 709 ESPSTAT_INC(esps_nopf); 710 error = EPFNOSUPPORT; 711 goto bad; 712 } 713 /* 714 DPRINTF(("%s: skip %d hlen %d rlen %d padding %d alen %d blksd %d\n", 715 __func__, skip, hlen, rlen, padding, alen, blks)); */ 716 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 717 DPRINTF(("%s: packet in SA %s/%08lx got too big " 718 "(len %u, max len %u)\n", __func__, 719 ipsec_address(&saidx->dst, buf, sizeof(buf)), 720 (u_long) ntohl(sav->spi), 721 skip + hlen + rlen + padding + alen, maxpacketsize)); 722 ESPSTAT_INC(esps_toobig); 723 error = EMSGSIZE; 724 goto bad; 725 } 726 727 /* Update the counters. */ 728 ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip); 729 730 m = m_unshare(m, M_NOWAIT); 731 if (m == NULL) { 732 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 733 ipsec_address(&saidx->dst, buf, sizeof(buf)), 734 (u_long) ntohl(sav->spi))); 735 ESPSTAT_INC(esps_hdrops); 736 error = ENOBUFS; 737 goto bad; 738 } 739 740 /* Inject ESP header. */ 741 mo = m_makespace(m, skip, hlen, &roff); 742 if (mo == NULL) { 743 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 744 __func__, hlen, ipsec_address(&saidx->dst, buf, 745 sizeof(buf)), (u_long) ntohl(sav->spi))); 746 ESPSTAT_INC(esps_hdrops); /* XXX diffs from openbsd */ 747 error = ENOBUFS; 748 goto bad; 749 } 750 751 /* Initialize ESP header. */ 752 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, 753 sizeof(uint32_t)); 754 SECASVAR_LOCK(sav); 755 if (sav->replay) { 756 uint32_t replay; 757 758 #ifdef REGRESSION 759 /* Emulate replay attack when ipsec_replay is TRUE. */ 760 if (!V_ipsec_replay) 761 #endif 762 sav->replay->count++; 763 replay = htonl(sav->replay->count); 764 765 bcopy((caddr_t) &replay, mtod(mo, caddr_t) + roff + 766 sizeof(uint32_t), sizeof(uint32_t)); 767 } 768 cryptoid = sav->tdb_cryptoid; 769 if (SAV_ISCTRORGCM(sav)) 770 cntr = sav->cntr++; 771 SECASVAR_UNLOCK(sav); 772 773 /* 774 * Add padding -- better to do it ourselves than use the crypto engine, 775 * although if/when we support compression, we'd have to do that. 776 */ 777 pad = (u_char *) m_pad(m, padding + alen); 778 if (pad == NULL) { 779 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 780 ipsec_address(&saidx->dst, buf, sizeof(buf)), 781 (u_long) ntohl(sav->spi))); 782 m = NULL; /* NB: free'd by m_pad */ 783 error = ENOBUFS; 784 goto bad; 785 } 786 787 /* 788 * Add padding: random, zero, or self-describing. 789 * XXX catch unexpected setting 790 */ 791 switch (sav->flags & SADB_X_EXT_PMASK) { 792 case SADB_X_EXT_PRAND: 793 arc4random_buf(pad, padding - 2); 794 break; 795 case SADB_X_EXT_PZERO: 796 bzero(pad, padding - 2); 797 break; 798 case SADB_X_EXT_PSEQ: 799 for (i = 0; i < padding - 2; i++) 800 pad[i] = i+1; 801 break; 802 } 803 804 /* Fix padding length and Next Protocol in padding itself. */ 805 pad[padding - 2] = padding - 2; 806 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 807 808 /* Fix Next Protocol in IPv4/IPv6 header. */ 809 prot = IPPROTO_ESP; 810 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 811 812 /* Get crypto descriptors. */ 813 crp = crypto_getreq(esph != NULL ? 2 : 1); 814 if (crp == NULL) { 815 DPRINTF(("%s: failed to acquire crypto descriptors\n", 816 __func__)); 817 ESPSTAT_INC(esps_crypto); 818 error = ENOBUFS; 819 goto bad; 820 } 821 822 /* IPsec-specific opaque crypto info. */ 823 xd = malloc(sizeof(struct xform_data), M_XDATA, M_NOWAIT | M_ZERO); 824 if (xd == NULL) { 825 crypto_freereq(crp); 826 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 827 ESPSTAT_INC(esps_crypto); 828 error = ENOBUFS; 829 goto bad; 830 } 831 832 crde = crp->crp_desc; 833 crda = crde->crd_next; 834 835 /* Encryption descriptor. */ 836 crde->crd_skip = skip + hlen; 837 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 838 crde->crd_flags = CRD_F_ENCRYPT; 839 crde->crd_inject = skip + hlen - sav->ivlen; 840 841 /* Encryption operation. */ 842 crde->crd_alg = espx->type; 843 if (SAV_ISCTRORGCM(sav)) { 844 ivp = &crde->crd_iv[0]; 845 846 /* GCM IV Format: RFC4106 4 */ 847 /* CTR IV Format: RFC3686 4 */ 848 /* Salt is last four bytes of key, RFC4106 8.1 */ 849 /* Nonce is last four bytes of key, RFC3686 5.1 */ 850 memcpy(ivp, sav->key_enc->key_data + 851 _KEYLEN(sav->key_enc) - 4, 4); 852 be64enc(&ivp[4], cntr); 853 if (SAV_ISCTR(sav)) { 854 /* Initial block counter is 1, RFC3686 4 */ 855 /* XXXAE: should we use this only for first packet? */ 856 be32enc(&ivp[sav->ivlen + 4], 1); 857 } 858 859 m_copyback(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); 860 crde->crd_flags |= CRD_F_IV_EXPLICIT|CRD_F_IV_PRESENT; 861 } 862 863 /* Callback parameters */ 864 xd->sp = sp; 865 xd->sav = sav; 866 xd->idx = idx; 867 xd->cryptoid = cryptoid; 868 xd->vnet = curvnet; 869 870 /* Crypto operation descriptor. */ 871 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 872 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 873 if (V_async_crypto) 874 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 875 crp->crp_buf = (caddr_t) m; 876 crp->crp_callback = esp_output_cb; 877 crp->crp_opaque = (caddr_t) xd; 878 crp->crp_session = cryptoid; 879 880 if (esph) { 881 /* Authentication descriptor. */ 882 crda->crd_alg = esph->type; 883 crda->crd_skip = skip; 884 if (SAV_ISGCM(sav)) 885 crda->crd_len = 8; /* RFC4106 5, SPI + SN */ 886 else 887 crda->crd_len = m->m_pkthdr.len - (skip + alen); 888 crda->crd_inject = m->m_pkthdr.len - alen; 889 } 890 891 return crypto_dispatch(crp); 892 bad: 893 if (m) 894 m_freem(m); 895 key_freesav(&sav); 896 key_freesp(&sp); 897 return (error); 898 } 899 /* 900 * ESP output callback from the crypto driver. 901 */ 902 static int 903 esp_output_cb(struct cryptop *crp) 904 { 905 struct xform_data *xd; 906 struct secpolicy *sp; 907 struct secasvar *sav; 908 struct mbuf *m; 909 crypto_session_t cryptoid; 910 u_int idx; 911 int error; 912 913 xd = (struct xform_data *) crp->crp_opaque; 914 CURVNET_SET(xd->vnet); 915 m = (struct mbuf *) crp->crp_buf; 916 sp = xd->sp; 917 sav = xd->sav; 918 idx = xd->idx; 919 cryptoid = xd->cryptoid; 920 921 /* Check for crypto errors. */ 922 if (crp->crp_etype) { 923 if (crp->crp_etype == EAGAIN) { 924 /* Reset the session ID */ 925 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 926 crypto_freesession(cryptoid); 927 xd->cryptoid = crp->crp_session; 928 CURVNET_RESTORE(); 929 return (crypto_dispatch(crp)); 930 } 931 ESPSTAT_INC(esps_noxform); 932 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 933 error = crp->crp_etype; 934 m_freem(m); 935 goto bad; 936 } 937 938 /* Shouldn't happen... */ 939 if (m == NULL) { 940 ESPSTAT_INC(esps_crypto); 941 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 942 error = EINVAL; 943 goto bad; 944 } 945 free(xd, M_XDATA); 946 crypto_freereq(crp); 947 ESPSTAT_INC(esps_hist[sav->alg_enc]); 948 if (sav->tdb_authalgxform != NULL) 949 AHSTAT_INC(ahs_hist[sav->alg_auth]); 950 951 #ifdef REGRESSION 952 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 953 if (V_ipsec_integrity) { 954 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN]; 955 const struct auth_hash *esph; 956 957 /* 958 * Corrupt HMAC if we want to test integrity verification of 959 * the other side. 960 */ 961 esph = sav->tdb_authalgxform; 962 if (esph != NULL) { 963 int alen; 964 965 alen = xform_ah_authsize(esph); 966 m_copyback(m, m->m_pkthdr.len - alen, 967 alen, ipseczeroes); 968 } 969 } 970 #endif 971 972 /* NB: m is reclaimed by ipsec_process_done. */ 973 error = ipsec_process_done(m, sp, sav, idx); 974 CURVNET_RESTORE(); 975 return (error); 976 bad: 977 CURVNET_RESTORE(); 978 free(xd, M_XDATA); 979 crypto_freereq(crp); 980 key_freesav(&sav); 981 key_freesp(&sp); 982 return (error); 983 } 984 985 static struct xformsw esp_xformsw = { 986 .xf_type = XF_ESP, 987 .xf_name = "IPsec ESP", 988 .xf_init = esp_init, 989 .xf_zeroize = esp_zeroize, 990 .xf_input = esp_input, 991 .xf_output = esp_output, 992 }; 993 994 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 995 xform_attach, &esp_xformsw); 996 SYSUNINIT(esp_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 997 xform_detach, &esp_xformsw); 998