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 int esp_input_cb(struct cryptop *op); 98 static int esp_output_cb(struct cryptop *crp); 99 100 size_t 101 esp_hdrsiz(struct secasvar *sav) 102 { 103 size_t size; 104 105 if (sav != NULL) { 106 /*XXX not right for null algorithm--does it matter??*/ 107 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 108 ("SA with null xform")); 109 if (sav->flags & SADB_X_EXT_OLD) 110 size = sizeof (struct esp); 111 else 112 size = sizeof (struct newesp); 113 size += sav->tdb_encalgxform->blocksize + 9; 114 /*XXX need alg check???*/ 115 if (sav->tdb_authalgxform != NULL && sav->replay) 116 size += ah_hdrsiz(sav); 117 } else { 118 /* 119 * base header size 120 * + max iv length for CBC mode 121 * + max pad length 122 * + sizeof (pad length field) 123 * + sizeof (next header field) 124 * + max icv supported. 125 */ 126 size = sizeof (struct newesp) + EALG_MAX_BLOCK_LEN + 9 + 16; 127 } 128 return size; 129 } 130 131 /* 132 * esp_init() is called when an SPI is being set up. 133 */ 134 static int 135 esp_init(struct secasvar *sav, struct xformsw *xsp) 136 { 137 const struct enc_xform *txform; 138 struct cryptoini cria, crie; 139 int keylen; 140 int error; 141 142 txform = enc_algorithm_lookup(sav->alg_enc); 143 if (txform == NULL) { 144 DPRINTF(("%s: unsupported encryption algorithm %d\n", 145 __func__, sav->alg_enc)); 146 return EINVAL; 147 } 148 if (sav->key_enc == NULL) { 149 DPRINTF(("%s: no encoding key for %s algorithm\n", 150 __func__, txform->name)); 151 return EINVAL; 152 } 153 if ((sav->flags & (SADB_X_EXT_OLD | SADB_X_EXT_IV4B)) == 154 SADB_X_EXT_IV4B) { 155 DPRINTF(("%s: 4-byte IV not supported with protocol\n", 156 __func__)); 157 return EINVAL; 158 } 159 /* subtract off the salt, RFC4106, 8.1 and RFC3686, 5.1 */ 160 keylen = _KEYLEN(sav->key_enc) - SAV_ISCTRORGCM(sav) * 4; 161 if (txform->minkey > keylen || keylen > txform->maxkey) { 162 DPRINTF(("%s: invalid key length %u, must be in the range " 163 "[%u..%u] for algorithm %s\n", __func__, 164 keylen, txform->minkey, txform->maxkey, 165 txform->name)); 166 return EINVAL; 167 } 168 169 if (SAV_ISCTRORGCM(sav)) 170 sav->ivlen = 8; /* RFC4106 3.1 and RFC3686 3.1 */ 171 else 172 sav->ivlen = txform->ivsize; 173 174 /* 175 * Setup AH-related state. 176 */ 177 if (sav->alg_auth != 0) { 178 error = ah_init0(sav, xsp, &cria); 179 if (error) 180 return error; 181 } 182 183 /* NB: override anything set in ah_init0 */ 184 sav->tdb_xform = xsp; 185 sav->tdb_encalgxform = txform; 186 187 /* 188 * Whenever AES-GCM is used for encryption, one 189 * of the AES authentication algorithms is chosen 190 * as well, based on the key size. 191 */ 192 if (sav->alg_enc == SADB_X_EALG_AESGCM16) { 193 switch (keylen) { 194 case AES_128_GMAC_KEY_LEN: 195 sav->alg_auth = SADB_X_AALG_AES128GMAC; 196 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_128; 197 break; 198 case AES_192_GMAC_KEY_LEN: 199 sav->alg_auth = SADB_X_AALG_AES192GMAC; 200 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_192; 201 break; 202 case AES_256_GMAC_KEY_LEN: 203 sav->alg_auth = SADB_X_AALG_AES256GMAC; 204 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_256; 205 break; 206 default: 207 DPRINTF(("%s: invalid key length %u" 208 "for algorithm %s\n", __func__, 209 keylen, txform->name)); 210 return EINVAL; 211 } 212 bzero(&cria, sizeof(cria)); 213 cria.cri_alg = sav->tdb_authalgxform->type; 214 cria.cri_key = sav->key_enc->key_data; 215 cria.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISGCM(sav) * 32; 216 } 217 218 /* Initialize crypto session. */ 219 bzero(&crie, sizeof(crie)); 220 crie.cri_alg = sav->tdb_encalgxform->type; 221 crie.cri_key = sav->key_enc->key_data; 222 crie.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISCTRORGCM(sav) * 32; 223 224 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 225 /* init both auth & enc */ 226 crie.cri_next = &cria; 227 error = crypto_newsession(&sav->tdb_cryptoid, 228 &crie, V_crypto_support); 229 } else if (sav->tdb_encalgxform) { 230 error = crypto_newsession(&sav->tdb_cryptoid, 231 &crie, V_crypto_support); 232 } else if (sav->tdb_authalgxform) { 233 error = crypto_newsession(&sav->tdb_cryptoid, 234 &cria, V_crypto_support); 235 } else { 236 /* XXX cannot happen? */ 237 DPRINTF(("%s: no encoding OR authentication xform!\n", 238 __func__)); 239 error = EINVAL; 240 } 241 return error; 242 } 243 244 /* 245 * Paranoia. 246 */ 247 static int 248 esp_zeroize(struct secasvar *sav) 249 { 250 /* NB: ah_zerorize free's the crypto session state */ 251 int error = ah_zeroize(sav); 252 253 if (sav->key_enc) 254 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc)); 255 sav->tdb_encalgxform = NULL; 256 sav->tdb_xform = NULL; 257 return error; 258 } 259 260 /* 261 * ESP input processing, called (eventually) through the protocol switch. 262 */ 263 static int 264 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 265 { 266 IPSEC_DEBUG_DECLARE(char buf[128]); 267 const struct auth_hash *esph; 268 const struct enc_xform *espx; 269 struct xform_data *xd; 270 struct cryptodesc *crde; 271 struct cryptop *crp; 272 struct newesp *esp; 273 uint8_t *ivp; 274 uint64_t cryptoid; 275 int alen, error, hlen, plen; 276 277 IPSEC_ASSERT(sav != NULL, ("null SA")); 278 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); 279 280 error = EINVAL; 281 /* Valid IP Packet length ? */ 282 if ( (skip&3) || (m->m_pkthdr.len&3) ){ 283 DPRINTF(("%s: misaligned packet, skip %u pkt len %u", 284 __func__, skip, m->m_pkthdr.len)); 285 ESPSTAT_INC(esps_badilen); 286 goto bad; 287 } 288 /* XXX don't pullup, just copy header */ 289 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 290 291 esph = sav->tdb_authalgxform; 292 espx = sav->tdb_encalgxform; 293 294 /* Determine the ESP header and auth length */ 295 if (sav->flags & SADB_X_EXT_OLD) 296 hlen = sizeof (struct esp) + sav->ivlen; 297 else 298 hlen = sizeof (struct newesp) + sav->ivlen; 299 300 alen = xform_ah_authsize(esph); 301 302 /* 303 * Verify payload length is multiple of encryption algorithm 304 * block size. 305 * 306 * NB: This works for the null algorithm because the blocksize 307 * is 4 and all packets must be 4-byte aligned regardless 308 * of the algorithm. 309 */ 310 plen = m->m_pkthdr.len - (skip + hlen + alen); 311 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 312 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 313 " SA %s/%08lx\n", __func__, plen, espx->blocksize, 314 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 315 (u_long)ntohl(sav->spi))); 316 ESPSTAT_INC(esps_badilen); 317 goto bad; 318 } 319 320 /* 321 * Check sequence number. 322 */ 323 SECASVAR_LOCK(sav); 324 if (esph != NULL && sav->replay != NULL && sav->replay->wsize != 0) { 325 if (ipsec_chkreplay(ntohl(esp->esp_seq), sav) == 0) { 326 SECASVAR_UNLOCK(sav); 327 DPRINTF(("%s: packet replay check for %s\n", __func__, 328 ipsec_sa2str(sav, buf, sizeof(buf)))); 329 ESPSTAT_INC(esps_replay); 330 error = EACCES; 331 goto bad; 332 } 333 } 334 cryptoid = sav->tdb_cryptoid; 335 SECASVAR_UNLOCK(sav); 336 337 /* Update the counters */ 338 ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen)); 339 340 /* Get crypto descriptors */ 341 crp = crypto_getreq(esph && espx ? 2 : 1); 342 if (crp == NULL) { 343 DPRINTF(("%s: failed to acquire crypto descriptors\n", 344 __func__)); 345 ESPSTAT_INC(esps_crypto); 346 error = ENOBUFS; 347 goto bad; 348 } 349 350 /* Get IPsec-specific opaque pointer */ 351 xd = malloc(sizeof(*xd) + alen, M_XDATA, M_NOWAIT | M_ZERO); 352 if (xd == NULL) { 353 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 354 ESPSTAT_INC(esps_crypto); 355 crypto_freereq(crp); 356 error = ENOBUFS; 357 goto bad; 358 } 359 360 if (esph != NULL) { 361 struct cryptodesc *crda = crp->crp_desc; 362 363 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor")); 364 365 /* Authentication descriptor */ 366 crda->crd_skip = skip; 367 if (SAV_ISGCM(sav)) 368 crda->crd_len = 8; /* RFC4106 5, SPI + SN */ 369 else 370 crda->crd_len = m->m_pkthdr.len - (skip + alen); 371 crda->crd_inject = m->m_pkthdr.len - alen; 372 373 crda->crd_alg = esph->type; 374 375 /* Copy the authenticator */ 376 m_copydata(m, m->m_pkthdr.len - alen, alen, 377 (caddr_t) (xd + 1)); 378 379 /* Chain authentication request */ 380 crde = crda->crd_next; 381 } else { 382 crde = crp->crp_desc; 383 } 384 385 /* Crypto operation descriptor */ 386 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 387 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 388 if (V_async_crypto) 389 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 390 crp->crp_buf = (caddr_t) m; 391 crp->crp_callback = esp_input_cb; 392 crp->crp_sid = cryptoid; 393 crp->crp_opaque = (caddr_t) xd; 394 395 /* These are passed as-is to the callback */ 396 xd->sav = sav; 397 xd->protoff = protoff; 398 xd->skip = skip; 399 xd->cryptoid = cryptoid; 400 xd->vnet = curvnet; 401 402 /* Decryption descriptor */ 403 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor")); 404 crde->crd_skip = skip + hlen; 405 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 406 crde->crd_inject = skip + hlen - sav->ivlen; 407 408 if (SAV_ISCTRORGCM(sav)) { 409 ivp = &crde->crd_iv[0]; 410 411 /* GCM IV Format: RFC4106 4 */ 412 /* CTR IV Format: RFC3686 4 */ 413 /* Salt is last four bytes of key, RFC4106 8.1 */ 414 /* Nonce is last four bytes of key, RFC3686 5.1 */ 415 memcpy(ivp, sav->key_enc->key_data + 416 _KEYLEN(sav->key_enc) - 4, 4); 417 418 if (SAV_ISCTR(sav)) { 419 /* Initial block counter is 1, RFC3686 4 */ 420 be32enc(&ivp[sav->ivlen + 4], 1); 421 } 422 423 m_copydata(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); 424 crde->crd_flags |= CRD_F_IV_EXPLICIT; 425 } 426 427 crde->crd_alg = espx->type; 428 429 return (crypto_dispatch(crp)); 430 bad: 431 m_freem(m); 432 key_freesav(&sav); 433 return (error); 434 } 435 436 /* 437 * ESP input callback from the crypto driver. 438 */ 439 static int 440 esp_input_cb(struct cryptop *crp) 441 { 442 IPSEC_DEBUG_DECLARE(char buf[128]); 443 u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN]; 444 const struct auth_hash *esph; 445 struct mbuf *m; 446 struct cryptodesc *crd; 447 struct xform_data *xd; 448 struct secasvar *sav; 449 struct secasindex *saidx; 450 caddr_t ptr; 451 uint64_t cryptoid; 452 int hlen, skip, protoff, error, alen; 453 454 crd = crp->crp_desc; 455 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!")); 456 457 m = (struct mbuf *) crp->crp_buf; 458 xd = (struct xform_data *) crp->crp_opaque; 459 CURVNET_SET(xd->vnet); 460 sav = xd->sav; 461 skip = xd->skip; 462 protoff = xd->protoff; 463 cryptoid = xd->cryptoid; 464 saidx = &sav->sah->saidx; 465 esph = sav->tdb_authalgxform; 466 467 /* Check for crypto errors */ 468 if (crp->crp_etype) { 469 if (crp->crp_etype == EAGAIN) { 470 /* Reset the session ID */ 471 if (ipsec_updateid(sav, &crp->crp_sid, &cryptoid) != 0) 472 crypto_freesession(cryptoid); 473 xd->cryptoid = crp->crp_sid; 474 CURVNET_RESTORE(); 475 return (crypto_dispatch(crp)); 476 } 477 ESPSTAT_INC(esps_noxform); 478 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 479 error = crp->crp_etype; 480 goto bad; 481 } 482 483 /* Shouldn't happen... */ 484 if (m == NULL) { 485 ESPSTAT_INC(esps_crypto); 486 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 487 error = EINVAL; 488 goto bad; 489 } 490 ESPSTAT_INC(esps_hist[sav->alg_enc]); 491 492 /* If authentication was performed, check now. */ 493 if (esph != NULL) { 494 alen = xform_ah_authsize(esph); 495 AHSTAT_INC(ahs_hist[sav->alg_auth]); 496 /* Copy the authenticator from the packet */ 497 m_copydata(m, m->m_pkthdr.len - alen, alen, aalg); 498 ptr = (caddr_t) (xd + 1); 499 500 /* Verify authenticator */ 501 if (timingsafe_bcmp(ptr, aalg, alen) != 0) { 502 DPRINTF(("%s: authentication hash mismatch for " 503 "packet in SA %s/%08lx\n", __func__, 504 ipsec_address(&saidx->dst, buf, sizeof(buf)), 505 (u_long) ntohl(sav->spi))); 506 ESPSTAT_INC(esps_badauth); 507 error = EACCES; 508 goto bad; 509 } 510 m->m_flags |= M_AUTHIPDGM; 511 /* Remove trailing authenticator */ 512 m_adj(m, -alen); 513 } 514 515 /* Release the crypto descriptors */ 516 free(xd, M_XDATA), xd = NULL; 517 crypto_freereq(crp), crp = NULL; 518 519 /* 520 * Packet is now decrypted. 521 */ 522 m->m_flags |= M_DECRYPTED; 523 524 /* 525 * Update replay sequence number, if appropriate. 526 */ 527 if (sav->replay) { 528 u_int32_t seq; 529 530 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 531 sizeof (seq), (caddr_t) &seq); 532 SECASVAR_LOCK(sav); 533 if (ipsec_updatereplay(ntohl(seq), sav)) { 534 SECASVAR_UNLOCK(sav); 535 DPRINTF(("%s: packet replay check for %s\n", __func__, 536 ipsec_sa2str(sav, buf, sizeof(buf)))); 537 ESPSTAT_INC(esps_replay); 538 error = EACCES; 539 goto bad; 540 } 541 SECASVAR_UNLOCK(sav); 542 } 543 544 /* Determine the ESP header length */ 545 if (sav->flags & SADB_X_EXT_OLD) 546 hlen = sizeof (struct esp) + sav->ivlen; 547 else 548 hlen = sizeof (struct newesp) + sav->ivlen; 549 550 /* Remove the ESP header and IV from the mbuf. */ 551 error = m_striphdr(m, skip, hlen); 552 if (error) { 553 ESPSTAT_INC(esps_hdrops); 554 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 555 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 556 (u_long) ntohl(sav->spi))); 557 goto bad; 558 } 559 560 /* Save the last three bytes of decrypted data */ 561 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 562 563 /* Verify pad length */ 564 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 565 ESPSTAT_INC(esps_badilen); 566 DPRINTF(("%s: invalid padding length %d for %u byte packet " 567 "in SA %s/%08lx\n", __func__, lastthree[1], 568 m->m_pkthdr.len - skip, 569 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 570 (u_long) ntohl(sav->spi))); 571 error = EINVAL; 572 goto bad; 573 } 574 575 /* Verify correct decryption by checking the last padding bytes */ 576 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 577 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 578 ESPSTAT_INC(esps_badenc); 579 DPRINTF(("%s: decryption failed for packet in " 580 "SA %s/%08lx\n", __func__, ipsec_address( 581 &sav->sah->saidx.dst, buf, sizeof(buf)), 582 (u_long) ntohl(sav->spi))); 583 error = EINVAL; 584 goto bad; 585 } 586 } 587 588 /* Trim the mbuf chain to remove trailing authenticator and padding */ 589 m_adj(m, -(lastthree[1] + 2)); 590 591 /* Restore the Next Protocol field */ 592 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 593 594 switch (saidx->dst.sa.sa_family) { 595 #ifdef INET6 596 case AF_INET6: 597 error = ipsec6_common_input_cb(m, sav, skip, protoff); 598 break; 599 #endif 600 #ifdef INET 601 case AF_INET: 602 error = ipsec4_common_input_cb(m, sav, skip, protoff); 603 break; 604 #endif 605 default: 606 panic("%s: Unexpected address family: %d saidx=%p", __func__, 607 saidx->dst.sa.sa_family, saidx); 608 } 609 CURVNET_RESTORE(); 610 return error; 611 bad: 612 CURVNET_RESTORE(); 613 if (sav != NULL) 614 key_freesav(&sav); 615 if (m != NULL) 616 m_freem(m); 617 if (xd != NULL) 618 free(xd, M_XDATA); 619 if (crp != NULL) 620 crypto_freereq(crp); 621 return error; 622 } 623 /* 624 * ESP output routine, called by ipsec[46]_perform_request(). 625 */ 626 static int 627 esp_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav, 628 u_int idx, int skip, int protoff) 629 { 630 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]); 631 struct cryptodesc *crde = NULL, *crda = NULL; 632 struct cryptop *crp; 633 const struct auth_hash *esph; 634 const struct enc_xform *espx; 635 struct mbuf *mo = NULL; 636 struct xform_data *xd; 637 struct secasindex *saidx; 638 unsigned char *pad; 639 uint8_t *ivp; 640 uint64_t cntr, cryptoid; 641 int hlen, rlen, padding, blks, alen, i, roff; 642 int error, maxpacketsize; 643 uint8_t prot; 644 645 IPSEC_ASSERT(sav != NULL, ("null SA")); 646 esph = sav->tdb_authalgxform; 647 espx = sav->tdb_encalgxform; 648 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 649 650 if (sav->flags & SADB_X_EXT_OLD) 651 hlen = sizeof (struct esp) + sav->ivlen; 652 else 653 hlen = sizeof (struct newesp) + sav->ivlen; 654 655 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 656 /* 657 * RFC4303 2.4 Requires 4 byte alignment. 658 */ 659 blks = MAX(4, espx->blocksize); /* Cipher blocksize */ 660 661 /* XXX clamp padding length a la KAME??? */ 662 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 663 664 alen = xform_ah_authsize(esph); 665 666 ESPSTAT_INC(esps_output); 667 668 saidx = &sav->sah->saidx; 669 /* Check for maximum packet size violations. */ 670 switch (saidx->dst.sa.sa_family) { 671 #ifdef INET 672 case AF_INET: 673 maxpacketsize = IP_MAXPACKET; 674 break; 675 #endif /* INET */ 676 #ifdef INET6 677 case AF_INET6: 678 maxpacketsize = IPV6_MAXPACKET; 679 break; 680 #endif /* INET6 */ 681 default: 682 DPRINTF(("%s: unknown/unsupported protocol " 683 "family %d, SA %s/%08lx\n", __func__, 684 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst, 685 buf, sizeof(buf)), (u_long) ntohl(sav->spi))); 686 ESPSTAT_INC(esps_nopf); 687 error = EPFNOSUPPORT; 688 goto bad; 689 } 690 /* 691 DPRINTF(("%s: skip %d hlen %d rlen %d padding %d alen %d blksd %d\n", 692 __func__, skip, hlen, rlen, padding, alen, blks)); */ 693 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 694 DPRINTF(("%s: packet in SA %s/%08lx got too big " 695 "(len %u, max len %u)\n", __func__, 696 ipsec_address(&saidx->dst, buf, sizeof(buf)), 697 (u_long) ntohl(sav->spi), 698 skip + hlen + rlen + padding + alen, maxpacketsize)); 699 ESPSTAT_INC(esps_toobig); 700 error = EMSGSIZE; 701 goto bad; 702 } 703 704 /* Update the counters. */ 705 ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip); 706 707 m = m_unshare(m, M_NOWAIT); 708 if (m == NULL) { 709 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 710 ipsec_address(&saidx->dst, buf, sizeof(buf)), 711 (u_long) ntohl(sav->spi))); 712 ESPSTAT_INC(esps_hdrops); 713 error = ENOBUFS; 714 goto bad; 715 } 716 717 /* Inject ESP header. */ 718 mo = m_makespace(m, skip, hlen, &roff); 719 if (mo == NULL) { 720 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 721 __func__, hlen, ipsec_address(&saidx->dst, buf, 722 sizeof(buf)), (u_long) ntohl(sav->spi))); 723 ESPSTAT_INC(esps_hdrops); /* XXX diffs from openbsd */ 724 error = ENOBUFS; 725 goto bad; 726 } 727 728 /* Initialize ESP header. */ 729 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, 730 sizeof(uint32_t)); 731 SECASVAR_LOCK(sav); 732 if (sav->replay) { 733 uint32_t replay; 734 735 #ifdef REGRESSION 736 /* Emulate replay attack when ipsec_replay is TRUE. */ 737 if (!V_ipsec_replay) 738 #endif 739 sav->replay->count++; 740 replay = htonl(sav->replay->count); 741 742 bcopy((caddr_t) &replay, mtod(mo, caddr_t) + roff + 743 sizeof(uint32_t), sizeof(uint32_t)); 744 } 745 cryptoid = sav->tdb_cryptoid; 746 if (SAV_ISCTRORGCM(sav)) 747 cntr = sav->cntr++; 748 SECASVAR_UNLOCK(sav); 749 750 /* 751 * Add padding -- better to do it ourselves than use the crypto engine, 752 * although if/when we support compression, we'd have to do that. 753 */ 754 pad = (u_char *) m_pad(m, padding + alen); 755 if (pad == NULL) { 756 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 757 ipsec_address(&saidx->dst, buf, sizeof(buf)), 758 (u_long) ntohl(sav->spi))); 759 m = NULL; /* NB: free'd by m_pad */ 760 error = ENOBUFS; 761 goto bad; 762 } 763 764 /* 765 * Add padding: random, zero, or self-describing. 766 * XXX catch unexpected setting 767 */ 768 switch (sav->flags & SADB_X_EXT_PMASK) { 769 case SADB_X_EXT_PRAND: 770 (void) read_random(pad, padding - 2); 771 break; 772 case SADB_X_EXT_PZERO: 773 bzero(pad, padding - 2); 774 break; 775 case SADB_X_EXT_PSEQ: 776 for (i = 0; i < padding - 2; i++) 777 pad[i] = i+1; 778 break; 779 } 780 781 /* Fix padding length and Next Protocol in padding itself. */ 782 pad[padding - 2] = padding - 2; 783 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 784 785 /* Fix Next Protocol in IPv4/IPv6 header. */ 786 prot = IPPROTO_ESP; 787 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 788 789 /* Get crypto descriptors. */ 790 crp = crypto_getreq(esph != NULL ? 2 : 1); 791 if (crp == NULL) { 792 DPRINTF(("%s: failed to acquire crypto descriptors\n", 793 __func__)); 794 ESPSTAT_INC(esps_crypto); 795 error = ENOBUFS; 796 goto bad; 797 } 798 799 /* IPsec-specific opaque crypto info. */ 800 xd = malloc(sizeof(struct xform_data), M_XDATA, M_NOWAIT | M_ZERO); 801 if (xd == NULL) { 802 crypto_freereq(crp); 803 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 804 ESPSTAT_INC(esps_crypto); 805 error = ENOBUFS; 806 goto bad; 807 } 808 809 crde = crp->crp_desc; 810 crda = crde->crd_next; 811 812 /* Encryption descriptor. */ 813 crde->crd_skip = skip + hlen; 814 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 815 crde->crd_flags = CRD_F_ENCRYPT; 816 crde->crd_inject = skip + hlen - sav->ivlen; 817 818 /* Encryption operation. */ 819 crde->crd_alg = espx->type; 820 if (SAV_ISCTRORGCM(sav)) { 821 ivp = &crde->crd_iv[0]; 822 823 /* GCM IV Format: RFC4106 4 */ 824 /* CTR IV Format: RFC3686 4 */ 825 /* Salt is last four bytes of key, RFC4106 8.1 */ 826 /* Nonce is last four bytes of key, RFC3686 5.1 */ 827 memcpy(ivp, sav->key_enc->key_data + 828 _KEYLEN(sav->key_enc) - 4, 4); 829 be64enc(&ivp[4], cntr); 830 if (SAV_ISCTR(sav)) { 831 /* Initial block counter is 1, RFC3686 4 */ 832 /* XXXAE: should we use this only for first packet? */ 833 be32enc(&ivp[sav->ivlen + 4], 1); 834 } 835 836 m_copyback(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); 837 crde->crd_flags |= CRD_F_IV_EXPLICIT|CRD_F_IV_PRESENT; 838 } 839 840 /* Callback parameters */ 841 xd->sp = sp; 842 xd->sav = sav; 843 xd->idx = idx; 844 xd->cryptoid = cryptoid; 845 xd->vnet = curvnet; 846 847 /* Crypto operation descriptor. */ 848 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 849 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 850 if (V_async_crypto) 851 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 852 crp->crp_buf = (caddr_t) m; 853 crp->crp_callback = esp_output_cb; 854 crp->crp_opaque = (caddr_t) xd; 855 crp->crp_sid = cryptoid; 856 857 if (esph) { 858 /* Authentication descriptor. */ 859 crda->crd_alg = esph->type; 860 crda->crd_skip = skip; 861 if (SAV_ISGCM(sav)) 862 crda->crd_len = 8; /* RFC4106 5, SPI + SN */ 863 else 864 crda->crd_len = m->m_pkthdr.len - (skip + alen); 865 crda->crd_inject = m->m_pkthdr.len - alen; 866 } 867 868 return crypto_dispatch(crp); 869 bad: 870 if (m) 871 m_freem(m); 872 key_freesav(&sav); 873 key_freesp(&sp); 874 return (error); 875 } 876 /* 877 * ESP output callback from the crypto driver. 878 */ 879 static int 880 esp_output_cb(struct cryptop *crp) 881 { 882 struct xform_data *xd; 883 struct secpolicy *sp; 884 struct secasvar *sav; 885 struct mbuf *m; 886 uint64_t cryptoid; 887 u_int idx; 888 int error; 889 890 xd = (struct xform_data *) crp->crp_opaque; 891 CURVNET_SET(xd->vnet); 892 m = (struct mbuf *) crp->crp_buf; 893 sp = xd->sp; 894 sav = xd->sav; 895 idx = xd->idx; 896 cryptoid = xd->cryptoid; 897 898 /* Check for crypto errors. */ 899 if (crp->crp_etype) { 900 if (crp->crp_etype == EAGAIN) { 901 /* Reset the session ID */ 902 if (ipsec_updateid(sav, &crp->crp_sid, &cryptoid) != 0) 903 crypto_freesession(cryptoid); 904 xd->cryptoid = crp->crp_sid; 905 CURVNET_RESTORE(); 906 return (crypto_dispatch(crp)); 907 } 908 ESPSTAT_INC(esps_noxform); 909 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 910 error = crp->crp_etype; 911 m_freem(m); 912 goto bad; 913 } 914 915 /* Shouldn't happen... */ 916 if (m == NULL) { 917 ESPSTAT_INC(esps_crypto); 918 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 919 error = EINVAL; 920 goto bad; 921 } 922 free(xd, M_XDATA); 923 crypto_freereq(crp); 924 ESPSTAT_INC(esps_hist[sav->alg_enc]); 925 if (sav->tdb_authalgxform != NULL) 926 AHSTAT_INC(ahs_hist[sav->alg_auth]); 927 928 #ifdef REGRESSION 929 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 930 if (V_ipsec_integrity) { 931 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN]; 932 const struct auth_hash *esph; 933 934 /* 935 * Corrupt HMAC if we want to test integrity verification of 936 * the other side. 937 */ 938 esph = sav->tdb_authalgxform; 939 if (esph != NULL) { 940 int alen; 941 942 alen = xform_ah_authsize(esph); 943 m_copyback(m, m->m_pkthdr.len - alen, 944 alen, ipseczeroes); 945 } 946 } 947 #endif 948 949 /* NB: m is reclaimed by ipsec_process_done. */ 950 error = ipsec_process_done(m, sp, sav, idx); 951 CURVNET_RESTORE(); 952 return (error); 953 bad: 954 CURVNET_RESTORE(); 955 free(xd, M_XDATA); 956 crypto_freereq(crp); 957 key_freesav(&sav); 958 key_freesp(&sp); 959 return (error); 960 } 961 962 static struct xformsw esp_xformsw = { 963 .xf_type = XF_ESP, 964 .xf_name = "IPsec ESP", 965 .xf_init = esp_init, 966 .xf_zeroize = esp_zeroize, 967 .xf_input = esp_input, 968 .xf_output = esp_output, 969 }; 970 971 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 972 xform_attach, &esp_xformsw); 973 SYSUNINIT(esp_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 974 xform_detach, &esp_xformsw); 975