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