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 static struct timeval warninterval = { .tv_sec = 1, .tv_usec = 0 }; 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, &warninterval)) 166 gone_in(13, "DES cipher for IPsec"); 167 break; 168 case SADB_X_EALG_BLOWFISHCBC: 169 if (ratecheck(&blfwarn, &warninterval)) 170 gone_in(13, "Blowfish cipher for IPsec"); 171 break; 172 case SADB_X_EALG_CAST128CBC: 173 if (ratecheck(&castwarn, &warninterval)) 174 gone_in(13, "CAST cipher for IPsec"); 175 break; 176 case SADB_X_EALG_CAMELLIACBC: 177 if (ratecheck(&camelliawarn, &warninterval)) 178 gone_in(13, "Camellia cipher for IPsec"); 179 break; 180 } 181 182 /* subtract off the salt, RFC4106, 8.1 and RFC3686, 5.1 */ 183 keylen = _KEYLEN(sav->key_enc) - SAV_ISCTRORGCM(sav) * 4; 184 if (txform->minkey > keylen || keylen > txform->maxkey) { 185 DPRINTF(("%s: invalid key length %u, must be in the range " 186 "[%u..%u] for algorithm %s\n", __func__, 187 keylen, txform->minkey, txform->maxkey, 188 txform->name)); 189 return EINVAL; 190 } 191 192 if (SAV_ISCTRORGCM(sav)) 193 sav->ivlen = 8; /* RFC4106 3.1 and RFC3686 3.1 */ 194 else 195 sav->ivlen = txform->ivsize; 196 197 /* 198 * Setup AH-related state. 199 */ 200 if (sav->alg_auth != 0) { 201 error = ah_init0(sav, xsp, &cria); 202 if (error) 203 return error; 204 } 205 206 /* NB: override anything set in ah_init0 */ 207 sav->tdb_xform = xsp; 208 sav->tdb_encalgxform = txform; 209 210 /* 211 * Whenever AES-GCM is used for encryption, one 212 * of the AES authentication algorithms is chosen 213 * as well, based on the key size. 214 */ 215 if (sav->alg_enc == SADB_X_EALG_AESGCM16) { 216 switch (keylen) { 217 case AES_128_GMAC_KEY_LEN: 218 sav->alg_auth = SADB_X_AALG_AES128GMAC; 219 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_128; 220 break; 221 case AES_192_GMAC_KEY_LEN: 222 sav->alg_auth = SADB_X_AALG_AES192GMAC; 223 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_192; 224 break; 225 case AES_256_GMAC_KEY_LEN: 226 sav->alg_auth = SADB_X_AALG_AES256GMAC; 227 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_256; 228 break; 229 default: 230 DPRINTF(("%s: invalid key length %u" 231 "for algorithm %s\n", __func__, 232 keylen, txform->name)); 233 return EINVAL; 234 } 235 bzero(&cria, sizeof(cria)); 236 cria.cri_alg = sav->tdb_authalgxform->type; 237 cria.cri_key = sav->key_enc->key_data; 238 cria.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISGCM(sav) * 32; 239 } 240 241 /* Initialize crypto session. */ 242 bzero(&crie, sizeof(crie)); 243 crie.cri_alg = sav->tdb_encalgxform->type; 244 crie.cri_key = sav->key_enc->key_data; 245 crie.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISCTRORGCM(sav) * 32; 246 247 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 248 /* init both auth & enc */ 249 crie.cri_next = &cria; 250 error = crypto_newsession(&sav->tdb_cryptoid, 251 &crie, V_crypto_support); 252 } else if (sav->tdb_encalgxform) { 253 error = crypto_newsession(&sav->tdb_cryptoid, 254 &crie, V_crypto_support); 255 } else if (sav->tdb_authalgxform) { 256 error = crypto_newsession(&sav->tdb_cryptoid, 257 &cria, V_crypto_support); 258 } else { 259 /* XXX cannot happen? */ 260 DPRINTF(("%s: no encoding OR authentication xform!\n", 261 __func__)); 262 error = EINVAL; 263 } 264 return error; 265 } 266 267 /* 268 * Paranoia. 269 */ 270 static int 271 esp_zeroize(struct secasvar *sav) 272 { 273 /* NB: ah_zerorize free's the crypto session state */ 274 int error = ah_zeroize(sav); 275 276 if (sav->key_enc) 277 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc)); 278 sav->tdb_encalgxform = NULL; 279 sav->tdb_xform = NULL; 280 return error; 281 } 282 283 /* 284 * ESP input processing, called (eventually) through the protocol switch. 285 */ 286 static int 287 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 288 { 289 IPSEC_DEBUG_DECLARE(char buf[128]); 290 const struct auth_hash *esph; 291 const struct enc_xform *espx; 292 struct xform_data *xd; 293 struct cryptodesc *crde; 294 struct cryptop *crp; 295 struct newesp *esp; 296 uint8_t *ivp; 297 crypto_session_t cryptoid; 298 int alen, error, hlen, plen; 299 300 IPSEC_ASSERT(sav != NULL, ("null SA")); 301 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); 302 303 error = EINVAL; 304 /* Valid IP Packet length ? */ 305 if ( (skip&3) || (m->m_pkthdr.len&3) ){ 306 DPRINTF(("%s: misaligned packet, skip %u pkt len %u", 307 __func__, skip, m->m_pkthdr.len)); 308 ESPSTAT_INC(esps_badilen); 309 goto bad; 310 } 311 /* XXX don't pullup, just copy header */ 312 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 313 314 esph = sav->tdb_authalgxform; 315 espx = sav->tdb_encalgxform; 316 317 /* Determine the ESP header and auth length */ 318 if (sav->flags & SADB_X_EXT_OLD) 319 hlen = sizeof (struct esp) + sav->ivlen; 320 else 321 hlen = sizeof (struct newesp) + sav->ivlen; 322 323 alen = xform_ah_authsize(esph); 324 325 /* 326 * Verify payload length is multiple of encryption algorithm 327 * block size. 328 * 329 * NB: This works for the null algorithm because the blocksize 330 * is 4 and all packets must be 4-byte aligned regardless 331 * of the algorithm. 332 */ 333 plen = m->m_pkthdr.len - (skip + hlen + alen); 334 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 335 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 336 " SA %s/%08lx\n", __func__, plen, espx->blocksize, 337 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 338 (u_long)ntohl(sav->spi))); 339 ESPSTAT_INC(esps_badilen); 340 goto bad; 341 } 342 343 /* 344 * Check sequence number. 345 */ 346 SECASVAR_LOCK(sav); 347 if (esph != NULL && sav->replay != NULL && sav->replay->wsize != 0) { 348 if (ipsec_chkreplay(ntohl(esp->esp_seq), sav) == 0) { 349 SECASVAR_UNLOCK(sav); 350 DPRINTF(("%s: packet replay check for %s\n", __func__, 351 ipsec_sa2str(sav, buf, sizeof(buf)))); 352 ESPSTAT_INC(esps_replay); 353 error = EACCES; 354 goto bad; 355 } 356 } 357 cryptoid = sav->tdb_cryptoid; 358 SECASVAR_UNLOCK(sav); 359 360 /* Update the counters */ 361 ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen)); 362 363 /* Get crypto descriptors */ 364 crp = crypto_getreq(esph && espx ? 2 : 1); 365 if (crp == NULL) { 366 DPRINTF(("%s: failed to acquire crypto descriptors\n", 367 __func__)); 368 ESPSTAT_INC(esps_crypto); 369 error = ENOBUFS; 370 goto bad; 371 } 372 373 /* Get IPsec-specific opaque pointer */ 374 xd = malloc(sizeof(*xd) + alen, M_XDATA, M_NOWAIT | M_ZERO); 375 if (xd == NULL) { 376 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 377 ESPSTAT_INC(esps_crypto); 378 crypto_freereq(crp); 379 error = ENOBUFS; 380 goto bad; 381 } 382 383 if (esph != NULL) { 384 struct cryptodesc *crda = crp->crp_desc; 385 386 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor")); 387 388 /* Authentication descriptor */ 389 crda->crd_skip = skip; 390 if (SAV_ISGCM(sav)) 391 crda->crd_len = 8; /* RFC4106 5, SPI + SN */ 392 else 393 crda->crd_len = m->m_pkthdr.len - (skip + alen); 394 crda->crd_inject = m->m_pkthdr.len - alen; 395 396 crda->crd_alg = esph->type; 397 398 /* Copy the authenticator */ 399 m_copydata(m, m->m_pkthdr.len - alen, alen, 400 (caddr_t) (xd + 1)); 401 402 /* Chain authentication request */ 403 crde = crda->crd_next; 404 } else { 405 crde = crp->crp_desc; 406 } 407 408 /* Crypto operation descriptor */ 409 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 410 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 411 if (V_async_crypto) 412 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 413 crp->crp_buf = (caddr_t) m; 414 crp->crp_callback = esp_input_cb; 415 crp->crp_session = cryptoid; 416 crp->crp_opaque = (caddr_t) xd; 417 418 /* These are passed as-is to the callback */ 419 xd->sav = sav; 420 xd->protoff = protoff; 421 xd->skip = skip; 422 xd->cryptoid = cryptoid; 423 xd->vnet = curvnet; 424 425 /* Decryption descriptor */ 426 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor")); 427 crde->crd_skip = skip + hlen; 428 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 429 crde->crd_inject = skip + hlen - sav->ivlen; 430 431 if (SAV_ISCTRORGCM(sav)) { 432 ivp = &crde->crd_iv[0]; 433 434 /* GCM IV Format: RFC4106 4 */ 435 /* CTR IV Format: RFC3686 4 */ 436 /* Salt is last four bytes of key, RFC4106 8.1 */ 437 /* Nonce is last four bytes of key, RFC3686 5.1 */ 438 memcpy(ivp, sav->key_enc->key_data + 439 _KEYLEN(sav->key_enc) - 4, 4); 440 441 if (SAV_ISCTR(sav)) { 442 /* Initial block counter is 1, RFC3686 4 */ 443 be32enc(&ivp[sav->ivlen + 4], 1); 444 } 445 446 m_copydata(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); 447 crde->crd_flags |= CRD_F_IV_EXPLICIT; 448 } 449 450 crde->crd_alg = espx->type; 451 452 return (crypto_dispatch(crp)); 453 bad: 454 m_freem(m); 455 key_freesav(&sav); 456 return (error); 457 } 458 459 /* 460 * ESP input callback from the crypto driver. 461 */ 462 static int 463 esp_input_cb(struct cryptop *crp) 464 { 465 IPSEC_DEBUG_DECLARE(char buf[128]); 466 u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN]; 467 const struct auth_hash *esph; 468 struct mbuf *m; 469 struct cryptodesc *crd; 470 struct xform_data *xd; 471 struct secasvar *sav; 472 struct secasindex *saidx; 473 caddr_t ptr; 474 crypto_session_t cryptoid; 475 int hlen, skip, protoff, error, alen; 476 477 crd = crp->crp_desc; 478 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!")); 479 480 m = (struct mbuf *) crp->crp_buf; 481 xd = (struct xform_data *) crp->crp_opaque; 482 CURVNET_SET(xd->vnet); 483 sav = xd->sav; 484 skip = xd->skip; 485 protoff = xd->protoff; 486 cryptoid = xd->cryptoid; 487 saidx = &sav->sah->saidx; 488 esph = sav->tdb_authalgxform; 489 490 /* Check for crypto errors */ 491 if (crp->crp_etype) { 492 if (crp->crp_etype == EAGAIN) { 493 /* Reset the session ID */ 494 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 495 crypto_freesession(cryptoid); 496 xd->cryptoid = crp->crp_session; 497 CURVNET_RESTORE(); 498 return (crypto_dispatch(crp)); 499 } 500 ESPSTAT_INC(esps_noxform); 501 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 502 error = crp->crp_etype; 503 goto bad; 504 } 505 506 /* Shouldn't happen... */ 507 if (m == NULL) { 508 ESPSTAT_INC(esps_crypto); 509 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 510 error = EINVAL; 511 goto bad; 512 } 513 ESPSTAT_INC(esps_hist[sav->alg_enc]); 514 515 /* If authentication was performed, check now. */ 516 if (esph != NULL) { 517 alen = xform_ah_authsize(esph); 518 AHSTAT_INC(ahs_hist[sav->alg_auth]); 519 /* Copy the authenticator from the packet */ 520 m_copydata(m, m->m_pkthdr.len - alen, alen, aalg); 521 ptr = (caddr_t) (xd + 1); 522 523 /* Verify authenticator */ 524 if (timingsafe_bcmp(ptr, aalg, alen) != 0) { 525 DPRINTF(("%s: authentication hash mismatch for " 526 "packet in SA %s/%08lx\n", __func__, 527 ipsec_address(&saidx->dst, buf, sizeof(buf)), 528 (u_long) ntohl(sav->spi))); 529 ESPSTAT_INC(esps_badauth); 530 error = EACCES; 531 goto bad; 532 } 533 m->m_flags |= M_AUTHIPDGM; 534 /* Remove trailing authenticator */ 535 m_adj(m, -alen); 536 } 537 538 /* Release the crypto descriptors */ 539 free(xd, M_XDATA), xd = NULL; 540 crypto_freereq(crp), crp = NULL; 541 542 /* 543 * Packet is now decrypted. 544 */ 545 m->m_flags |= M_DECRYPTED; 546 547 /* 548 * Update replay sequence number, if appropriate. 549 */ 550 if (sav->replay) { 551 u_int32_t seq; 552 553 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 554 sizeof (seq), (caddr_t) &seq); 555 SECASVAR_LOCK(sav); 556 if (ipsec_updatereplay(ntohl(seq), sav)) { 557 SECASVAR_UNLOCK(sav); 558 DPRINTF(("%s: packet replay check for %s\n", __func__, 559 ipsec_sa2str(sav, buf, sizeof(buf)))); 560 ESPSTAT_INC(esps_replay); 561 error = EACCES; 562 goto bad; 563 } 564 SECASVAR_UNLOCK(sav); 565 } 566 567 /* Determine the ESP header length */ 568 if (sav->flags & SADB_X_EXT_OLD) 569 hlen = sizeof (struct esp) + sav->ivlen; 570 else 571 hlen = sizeof (struct newesp) + sav->ivlen; 572 573 /* Remove the ESP header and IV from the mbuf. */ 574 error = m_striphdr(m, skip, hlen); 575 if (error) { 576 ESPSTAT_INC(esps_hdrops); 577 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 578 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 579 (u_long) ntohl(sav->spi))); 580 goto bad; 581 } 582 583 /* Save the last three bytes of decrypted data */ 584 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 585 586 /* Verify pad length */ 587 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 588 ESPSTAT_INC(esps_badilen); 589 DPRINTF(("%s: invalid padding length %d for %u byte packet " 590 "in SA %s/%08lx\n", __func__, lastthree[1], 591 m->m_pkthdr.len - skip, 592 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 593 (u_long) ntohl(sav->spi))); 594 error = EINVAL; 595 goto bad; 596 } 597 598 /* Verify correct decryption by checking the last padding bytes */ 599 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 600 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 601 ESPSTAT_INC(esps_badenc); 602 DPRINTF(("%s: decryption failed for packet in " 603 "SA %s/%08lx\n", __func__, ipsec_address( 604 &sav->sah->saidx.dst, buf, sizeof(buf)), 605 (u_long) ntohl(sav->spi))); 606 error = EINVAL; 607 goto bad; 608 } 609 } 610 611 /* Trim the mbuf chain to remove trailing authenticator and padding */ 612 m_adj(m, -(lastthree[1] + 2)); 613 614 /* Restore the Next Protocol field */ 615 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 616 617 switch (saidx->dst.sa.sa_family) { 618 #ifdef INET6 619 case AF_INET6: 620 error = ipsec6_common_input_cb(m, sav, skip, protoff); 621 break; 622 #endif 623 #ifdef INET 624 case AF_INET: 625 error = ipsec4_common_input_cb(m, sav, skip, protoff); 626 break; 627 #endif 628 default: 629 panic("%s: Unexpected address family: %d saidx=%p", __func__, 630 saidx->dst.sa.sa_family, saidx); 631 } 632 CURVNET_RESTORE(); 633 return error; 634 bad: 635 CURVNET_RESTORE(); 636 if (sav != NULL) 637 key_freesav(&sav); 638 if (m != NULL) 639 m_freem(m); 640 if (xd != NULL) 641 free(xd, M_XDATA); 642 if (crp != NULL) 643 crypto_freereq(crp); 644 return error; 645 } 646 /* 647 * ESP output routine, called by ipsec[46]_perform_request(). 648 */ 649 static int 650 esp_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav, 651 u_int idx, int skip, int protoff) 652 { 653 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]); 654 struct cryptodesc *crde = NULL, *crda = NULL; 655 struct cryptop *crp; 656 const struct auth_hash *esph; 657 const struct enc_xform *espx; 658 struct mbuf *mo = NULL; 659 struct xform_data *xd; 660 struct secasindex *saidx; 661 unsigned char *pad; 662 uint8_t *ivp; 663 uint64_t cntr; 664 crypto_session_t cryptoid; 665 int hlen, rlen, padding, blks, alen, i, roff; 666 int error, maxpacketsize; 667 uint8_t prot; 668 669 IPSEC_ASSERT(sav != NULL, ("null SA")); 670 esph = sav->tdb_authalgxform; 671 espx = sav->tdb_encalgxform; 672 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 673 674 if (sav->flags & SADB_X_EXT_OLD) 675 hlen = sizeof (struct esp) + sav->ivlen; 676 else 677 hlen = sizeof (struct newesp) + sav->ivlen; 678 679 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 680 /* 681 * RFC4303 2.4 Requires 4 byte alignment. 682 */ 683 blks = MAX(4, espx->blocksize); /* Cipher blocksize */ 684 685 /* XXX clamp padding length a la KAME??? */ 686 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 687 688 alen = xform_ah_authsize(esph); 689 690 ESPSTAT_INC(esps_output); 691 692 saidx = &sav->sah->saidx; 693 /* Check for maximum packet size violations. */ 694 switch (saidx->dst.sa.sa_family) { 695 #ifdef INET 696 case AF_INET: 697 maxpacketsize = IP_MAXPACKET; 698 break; 699 #endif /* INET */ 700 #ifdef INET6 701 case AF_INET6: 702 maxpacketsize = IPV6_MAXPACKET; 703 break; 704 #endif /* INET6 */ 705 default: 706 DPRINTF(("%s: unknown/unsupported protocol " 707 "family %d, SA %s/%08lx\n", __func__, 708 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst, 709 buf, sizeof(buf)), (u_long) ntohl(sav->spi))); 710 ESPSTAT_INC(esps_nopf); 711 error = EPFNOSUPPORT; 712 goto bad; 713 } 714 /* 715 DPRINTF(("%s: skip %d hlen %d rlen %d padding %d alen %d blksd %d\n", 716 __func__, skip, hlen, rlen, padding, alen, blks)); */ 717 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 718 DPRINTF(("%s: packet in SA %s/%08lx got too big " 719 "(len %u, max len %u)\n", __func__, 720 ipsec_address(&saidx->dst, buf, sizeof(buf)), 721 (u_long) ntohl(sav->spi), 722 skip + hlen + rlen + padding + alen, maxpacketsize)); 723 ESPSTAT_INC(esps_toobig); 724 error = EMSGSIZE; 725 goto bad; 726 } 727 728 /* Update the counters. */ 729 ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip); 730 731 m = m_unshare(m, M_NOWAIT); 732 if (m == NULL) { 733 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 734 ipsec_address(&saidx->dst, buf, sizeof(buf)), 735 (u_long) ntohl(sav->spi))); 736 ESPSTAT_INC(esps_hdrops); 737 error = ENOBUFS; 738 goto bad; 739 } 740 741 /* Inject ESP header. */ 742 mo = m_makespace(m, skip, hlen, &roff); 743 if (mo == NULL) { 744 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 745 __func__, hlen, ipsec_address(&saidx->dst, buf, 746 sizeof(buf)), (u_long) ntohl(sav->spi))); 747 ESPSTAT_INC(esps_hdrops); /* XXX diffs from openbsd */ 748 error = ENOBUFS; 749 goto bad; 750 } 751 752 /* Initialize ESP header. */ 753 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, 754 sizeof(uint32_t)); 755 SECASVAR_LOCK(sav); 756 if (sav->replay) { 757 uint32_t replay; 758 759 #ifdef REGRESSION 760 /* Emulate replay attack when ipsec_replay is TRUE. */ 761 if (!V_ipsec_replay) 762 #endif 763 sav->replay->count++; 764 replay = htonl(sav->replay->count); 765 766 bcopy((caddr_t) &replay, mtod(mo, caddr_t) + roff + 767 sizeof(uint32_t), sizeof(uint32_t)); 768 } 769 cryptoid = sav->tdb_cryptoid; 770 if (SAV_ISCTRORGCM(sav)) 771 cntr = sav->cntr++; 772 SECASVAR_UNLOCK(sav); 773 774 /* 775 * Add padding -- better to do it ourselves than use the crypto engine, 776 * although if/when we support compression, we'd have to do that. 777 */ 778 pad = (u_char *) m_pad(m, padding + alen); 779 if (pad == NULL) { 780 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 781 ipsec_address(&saidx->dst, buf, sizeof(buf)), 782 (u_long) ntohl(sav->spi))); 783 m = NULL; /* NB: free'd by m_pad */ 784 error = ENOBUFS; 785 goto bad; 786 } 787 788 /* 789 * Add padding: random, zero, or self-describing. 790 * XXX catch unexpected setting 791 */ 792 switch (sav->flags & SADB_X_EXT_PMASK) { 793 case SADB_X_EXT_PRAND: 794 arc4random_buf(pad, padding - 2); 795 break; 796 case SADB_X_EXT_PZERO: 797 bzero(pad, padding - 2); 798 break; 799 case SADB_X_EXT_PSEQ: 800 for (i = 0; i < padding - 2; i++) 801 pad[i] = i+1; 802 break; 803 } 804 805 /* Fix padding length and Next Protocol in padding itself. */ 806 pad[padding - 2] = padding - 2; 807 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 808 809 /* Fix Next Protocol in IPv4/IPv6 header. */ 810 prot = IPPROTO_ESP; 811 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 812 813 /* Get crypto descriptors. */ 814 crp = crypto_getreq(esph != NULL ? 2 : 1); 815 if (crp == NULL) { 816 DPRINTF(("%s: failed to acquire crypto descriptors\n", 817 __func__)); 818 ESPSTAT_INC(esps_crypto); 819 error = ENOBUFS; 820 goto bad; 821 } 822 823 /* IPsec-specific opaque crypto info. */ 824 xd = malloc(sizeof(struct xform_data), M_XDATA, M_NOWAIT | M_ZERO); 825 if (xd == NULL) { 826 crypto_freereq(crp); 827 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 828 ESPSTAT_INC(esps_crypto); 829 error = ENOBUFS; 830 goto bad; 831 } 832 833 crde = crp->crp_desc; 834 crda = crde->crd_next; 835 836 /* Encryption descriptor. */ 837 crde->crd_skip = skip + hlen; 838 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 839 crde->crd_flags = CRD_F_ENCRYPT; 840 crde->crd_inject = skip + hlen - sav->ivlen; 841 842 /* Encryption operation. */ 843 crde->crd_alg = espx->type; 844 if (SAV_ISCTRORGCM(sav)) { 845 ivp = &crde->crd_iv[0]; 846 847 /* GCM IV Format: RFC4106 4 */ 848 /* CTR IV Format: RFC3686 4 */ 849 /* Salt is last four bytes of key, RFC4106 8.1 */ 850 /* Nonce is last four bytes of key, RFC3686 5.1 */ 851 memcpy(ivp, sav->key_enc->key_data + 852 _KEYLEN(sav->key_enc) - 4, 4); 853 be64enc(&ivp[4], cntr); 854 if (SAV_ISCTR(sav)) { 855 /* Initial block counter is 1, RFC3686 4 */ 856 /* XXXAE: should we use this only for first packet? */ 857 be32enc(&ivp[sav->ivlen + 4], 1); 858 } 859 860 m_copyback(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); 861 crde->crd_flags |= CRD_F_IV_EXPLICIT|CRD_F_IV_PRESENT; 862 } 863 864 /* Callback parameters */ 865 xd->sp = sp; 866 xd->sav = sav; 867 xd->idx = idx; 868 xd->cryptoid = cryptoid; 869 xd->vnet = curvnet; 870 871 /* Crypto operation descriptor. */ 872 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 873 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 874 if (V_async_crypto) 875 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 876 crp->crp_buf = (caddr_t) m; 877 crp->crp_callback = esp_output_cb; 878 crp->crp_opaque = (caddr_t) xd; 879 crp->crp_session = cryptoid; 880 881 if (esph) { 882 /* Authentication descriptor. */ 883 crda->crd_alg = esph->type; 884 crda->crd_skip = skip; 885 if (SAV_ISGCM(sav)) 886 crda->crd_len = 8; /* RFC4106 5, SPI + SN */ 887 else 888 crda->crd_len = m->m_pkthdr.len - (skip + alen); 889 crda->crd_inject = m->m_pkthdr.len - alen; 890 } 891 892 return crypto_dispatch(crp); 893 bad: 894 if (m) 895 m_freem(m); 896 key_freesav(&sav); 897 key_freesp(&sp); 898 return (error); 899 } 900 /* 901 * ESP output callback from the crypto driver. 902 */ 903 static int 904 esp_output_cb(struct cryptop *crp) 905 { 906 struct xform_data *xd; 907 struct secpolicy *sp; 908 struct secasvar *sav; 909 struct mbuf *m; 910 crypto_session_t cryptoid; 911 u_int idx; 912 int error; 913 914 xd = (struct xform_data *) crp->crp_opaque; 915 CURVNET_SET(xd->vnet); 916 m = (struct mbuf *) crp->crp_buf; 917 sp = xd->sp; 918 sav = xd->sav; 919 idx = xd->idx; 920 cryptoid = xd->cryptoid; 921 922 /* Check for crypto errors. */ 923 if (crp->crp_etype) { 924 if (crp->crp_etype == EAGAIN) { 925 /* Reset the session ID */ 926 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 927 crypto_freesession(cryptoid); 928 xd->cryptoid = crp->crp_session; 929 CURVNET_RESTORE(); 930 return (crypto_dispatch(crp)); 931 } 932 ESPSTAT_INC(esps_noxform); 933 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 934 error = crp->crp_etype; 935 m_freem(m); 936 goto bad; 937 } 938 939 /* Shouldn't happen... */ 940 if (m == NULL) { 941 ESPSTAT_INC(esps_crypto); 942 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 943 error = EINVAL; 944 goto bad; 945 } 946 free(xd, M_XDATA); 947 crypto_freereq(crp); 948 ESPSTAT_INC(esps_hist[sav->alg_enc]); 949 if (sav->tdb_authalgxform != NULL) 950 AHSTAT_INC(ahs_hist[sav->alg_auth]); 951 952 #ifdef REGRESSION 953 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 954 if (V_ipsec_integrity) { 955 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN]; 956 const struct auth_hash *esph; 957 958 /* 959 * Corrupt HMAC if we want to test integrity verification of 960 * the other side. 961 */ 962 esph = sav->tdb_authalgxform; 963 if (esph != NULL) { 964 int alen; 965 966 alen = xform_ah_authsize(esph); 967 m_copyback(m, m->m_pkthdr.len - alen, 968 alen, ipseczeroes); 969 } 970 } 971 #endif 972 973 /* NB: m is reclaimed by ipsec_process_done. */ 974 error = ipsec_process_done(m, sp, sav, idx); 975 CURVNET_RESTORE(); 976 return (error); 977 bad: 978 CURVNET_RESTORE(); 979 free(xd, M_XDATA); 980 crypto_freereq(crp); 981 key_freesav(&sav); 982 key_freesp(&sp); 983 return (error); 984 } 985 986 static struct xformsw esp_xformsw = { 987 .xf_type = XF_ESP, 988 .xf_name = "IPsec ESP", 989 .xf_init = esp_init, 990 .xf_zeroize = esp_zeroize, 991 .xf_input = esp_input, 992 .xf_output = esp_output, 993 }; 994 995 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 996 xform_attach, &esp_xformsw); 997 SYSUNINIT(esp_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 998 xform_detach, &esp_xformsw); 999