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/rwlock.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 /* 101 * NB: this is public for use by the PF_KEY support. 102 * NB: if you add support here; be sure to add code to esp_attach below! 103 */ 104 struct enc_xform * 105 esp_algorithm_lookup(int alg) 106 { 107 if (alg >= ESP_ALG_MAX) 108 return NULL; 109 switch (alg) { 110 case SADB_EALG_DESCBC: 111 return &enc_xform_des; 112 case SADB_EALG_3DESCBC: 113 return &enc_xform_3des; 114 case SADB_X_EALG_AES: 115 return &enc_xform_rijndael128; 116 case SADB_X_EALG_BLOWFISHCBC: 117 return &enc_xform_blf; 118 case SADB_X_EALG_CAST128CBC: 119 return &enc_xform_cast5; 120 case SADB_EALG_NULL: 121 return &enc_xform_null; 122 case SADB_X_EALG_CAMELLIACBC: 123 return &enc_xform_camellia; 124 case SADB_X_EALG_AESCTR: 125 return &enc_xform_aes_icm; 126 case SADB_X_EALG_AESGCM16: 127 return &enc_xform_aes_nist_gcm; 128 case SADB_X_EALG_AESGMAC: 129 return &enc_xform_aes_nist_gmac; 130 } 131 return NULL; 132 } 133 134 size_t 135 esp_hdrsiz(struct secasvar *sav) 136 { 137 size_t size; 138 139 if (sav != NULL) { 140 /*XXX not right for null algorithm--does it matter??*/ 141 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 142 ("SA with null xform")); 143 if (sav->flags & SADB_X_EXT_OLD) 144 size = sizeof (struct esp); 145 else 146 size = sizeof (struct newesp); 147 size += sav->tdb_encalgxform->blocksize + 9; 148 /*XXX need alg check???*/ 149 if (sav->tdb_authalgxform != NULL && sav->replay) 150 size += ah_hdrsiz(sav); 151 } else { 152 /* 153 * base header size 154 * + max iv length for CBC mode 155 * + max pad length 156 * + sizeof (pad length field) 157 * + sizeof (next header field) 158 * + max icv supported. 159 */ 160 size = sizeof (struct newesp) + EALG_MAX_BLOCK_LEN + 9 + 16; 161 } 162 return size; 163 } 164 165 /* 166 * esp_init() is called when an SPI is being set up. 167 */ 168 static int 169 esp_init(struct secasvar *sav, struct xformsw *xsp) 170 { 171 struct enc_xform *txform; 172 struct cryptoini cria, crie; 173 int keylen; 174 int error; 175 176 txform = esp_algorithm_lookup(sav->alg_enc); 177 if (txform == NULL) { 178 DPRINTF(("%s: unsupported encryption algorithm %d\n", 179 __func__, sav->alg_enc)); 180 return EINVAL; 181 } 182 if (sav->key_enc == NULL) { 183 DPRINTF(("%s: no encoding key for %s algorithm\n", 184 __func__, txform->name)); 185 return EINVAL; 186 } 187 if ((sav->flags & (SADB_X_EXT_OLD | SADB_X_EXT_IV4B)) == 188 SADB_X_EXT_IV4B) { 189 DPRINTF(("%s: 4-byte IV not supported with protocol\n", 190 __func__)); 191 return EINVAL; 192 } 193 /* subtract off the salt, RFC4106, 8.1 and RFC3686, 5.1 */ 194 keylen = _KEYLEN(sav->key_enc) - SAV_ISCTRORGCM(sav) * 4; 195 if (txform->minkey > keylen || keylen > txform->maxkey) { 196 DPRINTF(("%s: invalid key length %u, must be in the range " 197 "[%u..%u] for algorithm %s\n", __func__, 198 keylen, txform->minkey, txform->maxkey, 199 txform->name)); 200 return EINVAL; 201 } 202 203 /* 204 * NB: The null xform needs a non-zero blocksize to keep the 205 * crypto code happy but if we use it to set ivlen then 206 * the ESP header will be processed incorrectly. The 207 * compromise is to force it to zero here. 208 */ 209 if (SAV_ISCTRORGCM(sav)) 210 sav->ivlen = 8; /* RFC4106 3.1 and RFC3686 3.1 */ 211 else 212 sav->ivlen = (txform == &enc_xform_null ? 0 : txform->ivsize); 213 214 /* 215 * Setup AH-related state. 216 */ 217 if (sav->alg_auth != 0) { 218 error = ah_init0(sav, xsp, &cria); 219 if (error) 220 return error; 221 } 222 223 /* NB: override anything set in ah_init0 */ 224 sav->tdb_xform = xsp; 225 sav->tdb_encalgxform = txform; 226 227 /* 228 * Whenever AES-GCM is used for encryption, one 229 * of the AES authentication algorithms is chosen 230 * as well, based on the key size. 231 */ 232 if (sav->alg_enc == SADB_X_EALG_AESGCM16) { 233 switch (keylen) { 234 case AES_128_GMAC_KEY_LEN: 235 sav->alg_auth = SADB_X_AALG_AES128GMAC; 236 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_128; 237 break; 238 case AES_192_GMAC_KEY_LEN: 239 sav->alg_auth = SADB_X_AALG_AES192GMAC; 240 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_192; 241 break; 242 case AES_256_GMAC_KEY_LEN: 243 sav->alg_auth = SADB_X_AALG_AES256GMAC; 244 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_256; 245 break; 246 default: 247 DPRINTF(("%s: invalid key length %u" 248 "for algorithm %s\n", __func__, 249 keylen, txform->name)); 250 return EINVAL; 251 } 252 bzero(&cria, sizeof(cria)); 253 cria.cri_alg = sav->tdb_authalgxform->type; 254 cria.cri_key = sav->key_enc->key_data; 255 cria.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISGCM(sav) * 32; 256 } 257 258 /* Initialize crypto session. */ 259 bzero(&crie, sizeof(crie)); 260 crie.cri_alg = sav->tdb_encalgxform->type; 261 crie.cri_key = sav->key_enc->key_data; 262 crie.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISCTRORGCM(sav) * 32; 263 264 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 265 /* init both auth & enc */ 266 crie.cri_next = &cria; 267 error = crypto_newsession(&sav->tdb_cryptoid, 268 &crie, V_crypto_support); 269 } else if (sav->tdb_encalgxform) { 270 error = crypto_newsession(&sav->tdb_cryptoid, 271 &crie, V_crypto_support); 272 } else if (sav->tdb_authalgxform) { 273 error = crypto_newsession(&sav->tdb_cryptoid, 274 &cria, V_crypto_support); 275 } else { 276 /* XXX cannot happen? */ 277 DPRINTF(("%s: no encoding OR authentication xform!\n", 278 __func__)); 279 error = EINVAL; 280 } 281 return error; 282 } 283 284 /* 285 * Paranoia. 286 */ 287 static int 288 esp_zeroize(struct secasvar *sav) 289 { 290 /* NB: ah_zerorize free's the crypto session state */ 291 int error = ah_zeroize(sav); 292 293 if (sav->key_enc) 294 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc)); 295 sav->tdb_encalgxform = NULL; 296 sav->tdb_xform = NULL; 297 return error; 298 } 299 300 /* 301 * ESP input processing, called (eventually) through the protocol switch. 302 */ 303 static int 304 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 305 { 306 char buf[128]; 307 struct auth_hash *esph; 308 struct enc_xform *espx; 309 struct tdb_crypto *tc; 310 uint8_t *ivp; 311 int plen, alen, hlen; 312 struct newesp *esp; 313 struct cryptodesc *crde; 314 struct cryptop *crp; 315 316 IPSEC_ASSERT(sav != NULL, ("null SA")); 317 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); 318 319 /* Valid IP Packet length ? */ 320 if ( (skip&3) || (m->m_pkthdr.len&3) ){ 321 DPRINTF(("%s: misaligned packet, skip %u pkt len %u", 322 __func__, skip, m->m_pkthdr.len)); 323 ESPSTAT_INC(esps_badilen); 324 m_freem(m); 325 return EINVAL; 326 } 327 /* XXX don't pullup, just copy header */ 328 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 329 330 esph = sav->tdb_authalgxform; 331 espx = sav->tdb_encalgxform; 332 333 /* Determine the ESP header and auth length */ 334 if (sav->flags & SADB_X_EXT_OLD) 335 hlen = sizeof (struct esp) + sav->ivlen; 336 else 337 hlen = sizeof (struct newesp) + sav->ivlen; 338 339 alen = xform_ah_authsize(esph); 340 341 /* 342 * Verify payload length is multiple of encryption algorithm 343 * block size. 344 * 345 * NB: This works for the null algorithm because the blocksize 346 * is 4 and all packets must be 4-byte aligned regardless 347 * of the algorithm. 348 */ 349 plen = m->m_pkthdr.len - (skip + hlen + alen); 350 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 351 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 352 " SA %s/%08lx\n", __func__, plen, espx->blocksize, 353 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 354 (u_long)ntohl(sav->spi))); 355 ESPSTAT_INC(esps_badilen); 356 m_freem(m); 357 return EINVAL; 358 } 359 360 /* 361 * Check sequence number. 362 */ 363 if (esph != NULL && sav->replay != NULL && 364 !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) { 365 DPRINTF(("%s: packet replay check for %s\n", __func__, 366 ipsec_logsastr(sav, buf, sizeof(buf)))); /*XXX*/ 367 ESPSTAT_INC(esps_replay); 368 m_freem(m); 369 return ENOBUFS; /*XXX*/ 370 } 371 372 /* Update the counters */ 373 ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen)); 374 375 /* Get crypto descriptors */ 376 crp = crypto_getreq(esph && espx ? 2 : 1); 377 if (crp == NULL) { 378 DPRINTF(("%s: failed to acquire crypto descriptors\n", 379 __func__)); 380 ESPSTAT_INC(esps_crypto); 381 m_freem(m); 382 return ENOBUFS; 383 } 384 385 /* Get IPsec-specific opaque pointer */ 386 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen, 387 M_XDATA, M_NOWAIT | M_ZERO); 388 if (tc == NULL) { 389 crypto_freereq(crp); 390 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 391 ESPSTAT_INC(esps_crypto); 392 m_freem(m); 393 return ENOBUFS; 394 } 395 396 if (esph != NULL) { 397 struct cryptodesc *crda = crp->crp_desc; 398 399 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor")); 400 401 /* Authentication descriptor */ 402 crda->crd_skip = skip; 403 if (SAV_ISGCM(sav)) 404 crda->crd_len = 8; /* RFC4106 5, SPI + SN */ 405 else 406 crda->crd_len = m->m_pkthdr.len - (skip + alen); 407 crda->crd_inject = m->m_pkthdr.len - alen; 408 409 crda->crd_alg = esph->type; 410 411 /* Copy the authenticator */ 412 m_copydata(m, m->m_pkthdr.len - alen, alen, 413 (caddr_t) (tc + 1)); 414 415 /* Chain authentication request */ 416 crde = crda->crd_next; 417 } else { 418 crde = crp->crp_desc; 419 } 420 421 /* Crypto operation descriptor */ 422 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 423 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 424 crp->crp_buf = (caddr_t) m; 425 crp->crp_callback = esp_input_cb; 426 crp->crp_sid = sav->tdb_cryptoid; 427 crp->crp_opaque = (caddr_t) tc; 428 429 /* These are passed as-is to the callback */ 430 tc->tc_spi = sav->spi; 431 tc->tc_dst = sav->sah->saidx.dst; 432 tc->tc_proto = sav->sah->saidx.proto; 433 tc->tc_protoff = protoff; 434 tc->tc_skip = skip; 435 KEY_ADDREFSA(sav); 436 tc->tc_sav = sav; 437 438 /* Decryption descriptor */ 439 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor")); 440 crde->crd_skip = skip + hlen; 441 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 442 crde->crd_inject = skip + hlen - sav->ivlen; 443 444 if (SAV_ISCTRORGCM(sav)) { 445 ivp = &crde->crd_iv[0]; 446 447 /* GCM IV Format: RFC4106 4 */ 448 /* CTR IV Format: RFC3686 4 */ 449 /* Salt is last four bytes of key, RFC4106 8.1 */ 450 /* Nonce is last four bytes of key, RFC3686 5.1 */ 451 memcpy(ivp, sav->key_enc->key_data + 452 _KEYLEN(sav->key_enc) - 4, 4); 453 454 if (SAV_ISCTR(sav)) { 455 /* Initial block counter is 1, RFC3686 4 */ 456 be32enc(&ivp[sav->ivlen + 4], 1); 457 } 458 459 m_copydata(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); 460 crde->crd_flags |= CRD_F_IV_EXPLICIT; 461 } 462 463 crde->crd_alg = espx->type; 464 465 return (crypto_dispatch(crp)); 466 } 467 468 /* 469 * ESP input callback from the crypto driver. 470 */ 471 static int 472 esp_input_cb(struct cryptop *crp) 473 { 474 char buf[128]; 475 u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN]; 476 int hlen, skip, protoff, error, alen; 477 struct mbuf *m; 478 struct cryptodesc *crd; 479 struct auth_hash *esph; 480 struct enc_xform *espx; 481 struct tdb_crypto *tc; 482 struct secasvar *sav; 483 struct secasindex *saidx; 484 caddr_t ptr; 485 486 crd = crp->crp_desc; 487 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!")); 488 489 tc = (struct tdb_crypto *) crp->crp_opaque; 490 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!")); 491 skip = tc->tc_skip; 492 protoff = tc->tc_protoff; 493 m = (struct mbuf *) crp->crp_buf; 494 495 sav = tc->tc_sav; 496 IPSEC_ASSERT(sav != NULL, ("null SA!")); 497 498 saidx = &sav->sah->saidx; 499 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 500 saidx->dst.sa.sa_family == AF_INET6, 501 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 502 503 esph = sav->tdb_authalgxform; 504 espx = sav->tdb_encalgxform; 505 506 /* Check for crypto errors */ 507 if (crp->crp_etype) { 508 /* Reset the session ID */ 509 if (sav->tdb_cryptoid != 0) 510 sav->tdb_cryptoid = crp->crp_sid; 511 512 if (crp->crp_etype == EAGAIN) 513 return (crypto_dispatch(crp)); 514 515 ESPSTAT_INC(esps_noxform); 516 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 517 error = crp->crp_etype; 518 goto bad; 519 } 520 521 /* Shouldn't happen... */ 522 if (m == NULL) { 523 ESPSTAT_INC(esps_crypto); 524 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 525 error = EINVAL; 526 goto bad; 527 } 528 ESPSTAT_INC(esps_hist[sav->alg_enc]); 529 530 /* If authentication was performed, check now. */ 531 if (esph != NULL) { 532 alen = xform_ah_authsize(esph); 533 AHSTAT_INC(ahs_hist[sav->alg_auth]); 534 /* Copy the authenticator from the packet */ 535 m_copydata(m, m->m_pkthdr.len - alen, alen, aalg); 536 ptr = (caddr_t) (tc + 1); 537 538 /* Verify authenticator */ 539 if (timingsafe_bcmp(ptr, aalg, alen) != 0) { 540 DPRINTF(("%s: authentication hash mismatch for " 541 "packet in SA %s/%08lx\n", __func__, 542 ipsec_address(&saidx->dst, buf, sizeof(buf)), 543 (u_long) ntohl(sav->spi))); 544 ESPSTAT_INC(esps_badauth); 545 error = EACCES; 546 goto bad; 547 } 548 549 /* Remove trailing authenticator */ 550 m_adj(m, -alen); 551 } 552 553 /* Release the crypto descriptors */ 554 free(tc, M_XDATA), tc = NULL; 555 crypto_freereq(crp), crp = NULL; 556 557 /* 558 * Packet is now decrypted. 559 */ 560 m->m_flags |= M_DECRYPTED; 561 562 /* 563 * Update replay sequence number, if appropriate. 564 */ 565 if (sav->replay) { 566 u_int32_t seq; 567 568 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 569 sizeof (seq), (caddr_t) &seq); 570 if (ipsec_updatereplay(ntohl(seq), sav)) { 571 DPRINTF(("%s: packet replay check for %s\n", __func__, 572 ipsec_logsastr(sav, buf, sizeof(buf)))); 573 ESPSTAT_INC(esps_replay); 574 error = ENOBUFS; 575 goto bad; 576 } 577 } 578 579 /* Determine the ESP header length */ 580 if (sav->flags & SADB_X_EXT_OLD) 581 hlen = sizeof (struct esp) + sav->ivlen; 582 else 583 hlen = sizeof (struct newesp) + sav->ivlen; 584 585 /* Remove the ESP header and IV from the mbuf. */ 586 error = m_striphdr(m, skip, hlen); 587 if (error) { 588 ESPSTAT_INC(esps_hdrops); 589 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 590 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 591 (u_long) ntohl(sav->spi))); 592 goto bad; 593 } 594 595 /* Save the last three bytes of decrypted data */ 596 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 597 598 /* Verify pad length */ 599 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 600 ESPSTAT_INC(esps_badilen); 601 DPRINTF(("%s: invalid padding length %d for %u byte packet " 602 "in SA %s/%08lx\n", __func__, lastthree[1], 603 m->m_pkthdr.len - skip, 604 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 605 (u_long) ntohl(sav->spi))); 606 error = EINVAL; 607 goto bad; 608 } 609 610 /* Verify correct decryption by checking the last padding bytes */ 611 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 612 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 613 ESPSTAT_INC(esps_badenc); 614 DPRINTF(("%s: decryption failed for packet in " 615 "SA %s/%08lx\n", __func__, ipsec_address( 616 &sav->sah->saidx.dst, buf, sizeof(buf)), 617 (u_long) ntohl(sav->spi))); 618 error = EINVAL; 619 goto bad; 620 } 621 } 622 623 /* Trim the mbuf chain to remove trailing authenticator and padding */ 624 m_adj(m, -(lastthree[1] + 2)); 625 626 /* Restore the Next Protocol field */ 627 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 628 629 switch (saidx->dst.sa.sa_family) { 630 #ifdef INET6 631 case AF_INET6: 632 error = ipsec6_common_input_cb(m, sav, skip, protoff); 633 break; 634 #endif 635 #ifdef INET 636 case AF_INET: 637 error = ipsec4_common_input_cb(m, sav, skip, protoff); 638 break; 639 #endif 640 default: 641 panic("%s: Unexpected address family: %d saidx=%p", __func__, 642 saidx->dst.sa.sa_family, saidx); 643 } 644 645 KEY_FREESAV(&sav); 646 return error; 647 bad: 648 if (sav) 649 KEY_FREESAV(&sav); 650 if (m != NULL) 651 m_freem(m); 652 if (tc != NULL) 653 free(tc, M_XDATA); 654 if (crp != NULL) 655 crypto_freereq(crp); 656 return error; 657 } 658 659 /* 660 * ESP output routine, called by ipsec[46]_process_packet(). 661 */ 662 static int 663 esp_output(struct mbuf *m, struct ipsecrequest *isr, struct mbuf **mp, 664 int skip, int protoff) 665 { 666 char buf[INET6_ADDRSTRLEN]; 667 struct enc_xform *espx; 668 struct auth_hash *esph; 669 uint8_t *ivp; 670 uint64_t cntr; 671 int hlen, rlen, padding, blks, alen, i, roff; 672 struct mbuf *mo = (struct mbuf *) NULL; 673 struct tdb_crypto *tc; 674 struct secasvar *sav; 675 struct secasindex *saidx; 676 unsigned char *pad; 677 u_int8_t prot; 678 int error, maxpacketsize; 679 680 struct cryptodesc *crde = NULL, *crda = NULL; 681 struct cryptop *crp; 682 683 sav = isr->sav; 684 IPSEC_ASSERT(sav != NULL, ("null SA")); 685 esph = sav->tdb_authalgxform; 686 espx = sav->tdb_encalgxform; 687 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 688 689 if (sav->flags & SADB_X_EXT_OLD) 690 hlen = sizeof (struct esp) + sav->ivlen; 691 else 692 hlen = sizeof (struct newesp) + sav->ivlen; 693 694 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 695 /* 696 * RFC4303 2.4 Requires 4 byte alignment. 697 */ 698 blks = MAX(4, espx->blocksize); /* Cipher blocksize */ 699 700 /* XXX clamp padding length a la KAME??? */ 701 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 702 703 alen = xform_ah_authsize(esph); 704 705 ESPSTAT_INC(esps_output); 706 707 saidx = &sav->sah->saidx; 708 /* Check for maximum packet size violations. */ 709 switch (saidx->dst.sa.sa_family) { 710 #ifdef INET 711 case AF_INET: 712 maxpacketsize = IP_MAXPACKET; 713 break; 714 #endif /* INET */ 715 #ifdef INET6 716 case AF_INET6: 717 maxpacketsize = IPV6_MAXPACKET; 718 break; 719 #endif /* INET6 */ 720 default: 721 DPRINTF(("%s: unknown/unsupported protocol " 722 "family %d, SA %s/%08lx\n", __func__, 723 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst, 724 buf, sizeof(buf)), (u_long) ntohl(sav->spi))); 725 ESPSTAT_INC(esps_nopf); 726 error = EPFNOSUPPORT; 727 goto bad; 728 } 729 DPRINTF(("%s: skip %d hlen %d rlen %d padding %d alen %d blksd %d\n", 730 __func__, skip, hlen, rlen, padding, alen, blks)); 731 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 732 DPRINTF(("%s: packet in SA %s/%08lx got too big " 733 "(len %u, max len %u)\n", __func__, 734 ipsec_address(&saidx->dst, buf, sizeof(buf)), 735 (u_long) ntohl(sav->spi), 736 skip + hlen + rlen + padding + alen, maxpacketsize)); 737 ESPSTAT_INC(esps_toobig); 738 error = EMSGSIZE; 739 goto bad; 740 } 741 742 /* Update the counters. */ 743 ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip); 744 745 m = m_unshare(m, M_NOWAIT); 746 if (m == NULL) { 747 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 748 ipsec_address(&saidx->dst, buf, sizeof(buf)), 749 (u_long) ntohl(sav->spi))); 750 ESPSTAT_INC(esps_hdrops); 751 error = ENOBUFS; 752 goto bad; 753 } 754 755 /* Inject ESP header. */ 756 mo = m_makespace(m, skip, hlen, &roff); 757 if (mo == NULL) { 758 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 759 __func__, hlen, ipsec_address(&saidx->dst, buf, 760 sizeof(buf)), (u_long) ntohl(sav->spi))); 761 ESPSTAT_INC(esps_hdrops); /* XXX diffs from openbsd */ 762 error = ENOBUFS; 763 goto bad; 764 } 765 766 /* Initialize ESP header. */ 767 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t)); 768 if (sav->replay) { 769 u_int32_t replay; 770 771 #ifdef REGRESSION 772 /* Emulate replay attack when ipsec_replay is TRUE. */ 773 if (!V_ipsec_replay) 774 #endif 775 sav->replay->count++; 776 replay = htonl(sav->replay->count); 777 bcopy((caddr_t) &replay, 778 mtod(mo, caddr_t) + roff + sizeof(u_int32_t), 779 sizeof(u_int32_t)); 780 } 781 782 /* 783 * Add padding -- better to do it ourselves than use the crypto engine, 784 * although if/when we support compression, we'd have to do that. 785 */ 786 pad = (u_char *) m_pad(m, padding + alen); 787 if (pad == NULL) { 788 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 789 ipsec_address(&saidx->dst, buf, sizeof(buf)), 790 (u_long) ntohl(sav->spi))); 791 m = NULL; /* NB: free'd by m_pad */ 792 error = ENOBUFS; 793 goto bad; 794 } 795 796 /* 797 * Add padding: random, zero, or self-describing. 798 * XXX catch unexpected setting 799 */ 800 switch (sav->flags & SADB_X_EXT_PMASK) { 801 case SADB_X_EXT_PRAND: 802 (void) read_random(pad, padding - 2); 803 break; 804 case SADB_X_EXT_PZERO: 805 bzero(pad, padding - 2); 806 break; 807 case SADB_X_EXT_PSEQ: 808 for (i = 0; i < padding - 2; i++) 809 pad[i] = i+1; 810 break; 811 } 812 813 /* Fix padding length and Next Protocol in padding itself. */ 814 pad[padding - 2] = padding - 2; 815 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 816 817 /* Fix Next Protocol in IPv4/IPv6 header. */ 818 prot = IPPROTO_ESP; 819 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 820 821 /* Get crypto descriptors. */ 822 crp = crypto_getreq(esph != NULL ? 2 : 1); 823 if (crp == NULL) { 824 DPRINTF(("%s: failed to acquire crypto descriptors\n", 825 __func__)); 826 ESPSTAT_INC(esps_crypto); 827 error = ENOBUFS; 828 goto bad; 829 } 830 831 /* IPsec-specific opaque crypto info. */ 832 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 833 M_XDATA, M_NOWAIT|M_ZERO); 834 if (tc == NULL) { 835 crypto_freereq(crp); 836 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 837 ESPSTAT_INC(esps_crypto); 838 error = ENOBUFS; 839 goto bad; 840 } 841 842 crde = crp->crp_desc; 843 crda = crde->crd_next; 844 845 /* Encryption descriptor. */ 846 crde->crd_skip = skip + hlen; 847 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 848 crde->crd_flags = CRD_F_ENCRYPT; 849 crde->crd_inject = skip + hlen - sav->ivlen; 850 851 /* Encryption operation. */ 852 crde->crd_alg = espx->type; 853 if (SAV_ISCTRORGCM(sav)) { 854 ivp = &crde->crd_iv[0]; 855 856 /* GCM IV Format: RFC4106 4 */ 857 /* CTR IV Format: RFC3686 4 */ 858 /* Salt is last four bytes of key, RFC4106 8.1 */ 859 /* Nonce is last four bytes of key, RFC3686 5.1 */ 860 memcpy(ivp, sav->key_enc->key_data + 861 _KEYLEN(sav->key_enc) - 4, 4); 862 SECASVAR_LOCK(sav); 863 cntr = sav->cntr++; 864 SECASVAR_UNLOCK(sav); 865 be64enc(&ivp[4], cntr); 866 867 if (SAV_ISCTR(sav)) { 868 /* Initial block counter is 1, RFC3686 4 */ 869 be32enc(&ivp[sav->ivlen + 4], 1); 870 } 871 872 m_copyback(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); 873 crde->crd_flags |= CRD_F_IV_EXPLICIT|CRD_F_IV_PRESENT; 874 } 875 876 /* Callback parameters */ 877 key_addref(isr->sp); 878 tc->tc_isr = isr; 879 KEY_ADDREFSA(sav); 880 tc->tc_sav = sav; 881 tc->tc_spi = sav->spi; 882 tc->tc_dst = saidx->dst; 883 tc->tc_proto = saidx->proto; 884 885 /* Crypto operation descriptor. */ 886 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 887 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 888 crp->crp_buf = (caddr_t) m; 889 crp->crp_callback = esp_output_cb; 890 crp->crp_opaque = (caddr_t) tc; 891 crp->crp_sid = sav->tdb_cryptoid; 892 893 if (esph) { 894 /* Authentication descriptor. */ 895 crda->crd_alg = esph->type; 896 crda->crd_skip = skip; 897 if (SAV_ISGCM(sav)) 898 crda->crd_len = 8; /* RFC4106 5, SPI + SN */ 899 else 900 crda->crd_len = m->m_pkthdr.len - (skip + alen); 901 crda->crd_inject = m->m_pkthdr.len - alen; 902 } 903 904 return crypto_dispatch(crp); 905 bad: 906 if (m) 907 m_freem(m); 908 return (error); 909 } 910 911 /* 912 * ESP output callback from the crypto driver. 913 */ 914 static int 915 esp_output_cb(struct cryptop *crp) 916 { 917 char buf[INET6_ADDRSTRLEN]; 918 struct tdb_crypto *tc; 919 struct ipsecrequest *isr; 920 struct secasvar *sav; 921 struct mbuf *m; 922 int error; 923 924 tc = (struct tdb_crypto *) crp->crp_opaque; 925 IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); 926 m = (struct mbuf *) crp->crp_buf; 927 928 isr = tc->tc_isr; 929 IPSEC_ASSERT(isr->sp != NULL, ("NULL isr->sp")); 930 IPSECREQUEST_LOCK(isr); 931 sav = tc->tc_sav; 932 933 /* With the isr lock released, SA pointer may have changed. */ 934 if (sav != isr->sav) { 935 ESPSTAT_INC(esps_notdb); 936 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 937 __func__, ipsec_address(&tc->tc_dst, buf, sizeof(buf)), 938 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 939 error = ENOBUFS; /*XXX*/ 940 goto bad; 941 } 942 943 /* Check for crypto errors. */ 944 if (crp->crp_etype) { 945 /* Reset session ID. */ 946 if (sav->tdb_cryptoid != 0) 947 sav->tdb_cryptoid = crp->crp_sid; 948 949 if (crp->crp_etype == EAGAIN) { 950 IPSECREQUEST_UNLOCK(isr); 951 return (crypto_dispatch(crp)); 952 } 953 954 ESPSTAT_INC(esps_noxform); 955 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 956 error = crp->crp_etype; 957 goto bad; 958 } 959 960 /* Shouldn't happen... */ 961 if (m == NULL) { 962 ESPSTAT_INC(esps_crypto); 963 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 964 error = EINVAL; 965 goto bad; 966 } 967 ESPSTAT_INC(esps_hist[sav->alg_enc]); 968 if (sav->tdb_authalgxform != NULL) 969 AHSTAT_INC(ahs_hist[sav->alg_auth]); 970 971 /* Release crypto descriptors. */ 972 free(tc, M_XDATA); 973 crypto_freereq(crp); 974 975 #ifdef REGRESSION 976 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 977 if (V_ipsec_integrity) { 978 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN]; 979 struct auth_hash *esph; 980 981 /* 982 * Corrupt HMAC if we want to test integrity verification of 983 * the other side. 984 */ 985 esph = sav->tdb_authalgxform; 986 if (esph != NULL) { 987 int alen; 988 989 alen = xform_ah_authsize(esph); 990 m_copyback(m, m->m_pkthdr.len - alen, 991 alen, ipseczeroes); 992 } 993 } 994 #endif 995 996 /* NB: m is reclaimed by ipsec_process_done. */ 997 error = ipsec_process_done(m, isr); 998 KEY_FREESAV(&sav); 999 IPSECREQUEST_UNLOCK(isr); 1000 KEY_FREESP(&isr->sp); 1001 return (error); 1002 bad: 1003 if (sav) 1004 KEY_FREESAV(&sav); 1005 IPSECREQUEST_UNLOCK(isr); 1006 KEY_FREESP(&isr->sp); 1007 if (m) 1008 m_freem(m); 1009 free(tc, M_XDATA); 1010 crypto_freereq(crp); 1011 return (error); 1012 } 1013 1014 static struct xformsw esp_xformsw = { 1015 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 1016 esp_init, esp_zeroize, esp_input, 1017 esp_output 1018 }; 1019 1020 static void 1021 esp_attach(void) 1022 { 1023 1024 xform_register(&esp_xformsw); 1025 } 1026 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL); 1027