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sys/netipsec/xform_esp.c
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1 /* $FreeBSD: releng/11.0/sys/netipsec/xform_esp.c 290924 2015-11-16 07:10:42Z ae $ */ 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 if (SAV_ISCTRORGCM(sav)) 204 sav->ivlen = 8; /* RFC4106 3.1 and RFC3686 3.1 */ 205 else 206 sav->ivlen = txform->ivsize; 207 208 /* 209 * Setup AH-related state. 210 */ 211 if (sav->alg_auth != 0) { 212 error = ah_init0(sav, xsp, &cria); 213 if (error) 214 return error; 215 } 216 217 /* NB: override anything set in ah_init0 */ 218 sav->tdb_xform = xsp; 219 sav->tdb_encalgxform = txform; 220 221 /* 222 * Whenever AES-GCM is used for encryption, one 223 * of the AES authentication algorithms is chosen 224 * as well, based on the key size. 225 */ 226 if (sav->alg_enc == SADB_X_EALG_AESGCM16) { 227 switch (keylen) { 228 case AES_128_GMAC_KEY_LEN: 229 sav->alg_auth = SADB_X_AALG_AES128GMAC; 230 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_128; 231 break; 232 case AES_192_GMAC_KEY_LEN: 233 sav->alg_auth = SADB_X_AALG_AES192GMAC; 234 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_192; 235 break; 236 case AES_256_GMAC_KEY_LEN: 237 sav->alg_auth = SADB_X_AALG_AES256GMAC; 238 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_256; 239 break; 240 default: 241 DPRINTF(("%s: invalid key length %u" 242 "for algorithm %s\n", __func__, 243 keylen, txform->name)); 244 return EINVAL; 245 } 246 bzero(&cria, sizeof(cria)); 247 cria.cri_alg = sav->tdb_authalgxform->type; 248 cria.cri_key = sav->key_enc->key_data; 249 cria.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISGCM(sav) * 32; 250 } 251 252 /* Initialize crypto session. */ 253 bzero(&crie, sizeof(crie)); 254 crie.cri_alg = sav->tdb_encalgxform->type; 255 crie.cri_key = sav->key_enc->key_data; 256 crie.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISCTRORGCM(sav) * 32; 257 258 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 259 /* init both auth & enc */ 260 crie.cri_next = &cria; 261 error = crypto_newsession(&sav->tdb_cryptoid, 262 &crie, V_crypto_support); 263 } else if (sav->tdb_encalgxform) { 264 error = crypto_newsession(&sav->tdb_cryptoid, 265 &crie, V_crypto_support); 266 } else if (sav->tdb_authalgxform) { 267 error = crypto_newsession(&sav->tdb_cryptoid, 268 &cria, V_crypto_support); 269 } else { 270 /* XXX cannot happen? */ 271 DPRINTF(("%s: no encoding OR authentication xform!\n", 272 __func__)); 273 error = EINVAL; 274 } 275 return error; 276 } 277 278 /* 279 * Paranoia. 280 */ 281 static int 282 esp_zeroize(struct secasvar *sav) 283 { 284 /* NB: ah_zerorize free's the crypto session state */ 285 int error = ah_zeroize(sav); 286 287 if (sav->key_enc) 288 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc)); 289 sav->tdb_encalgxform = NULL; 290 sav->tdb_xform = NULL; 291 return error; 292 } 293 294 /* 295 * ESP input processing, called (eventually) through the protocol switch. 296 */ 297 static int 298 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 299 { 300 char buf[128]; 301 struct auth_hash *esph; 302 struct enc_xform *espx; 303 struct tdb_crypto *tc; 304 uint8_t *ivp; 305 int plen, alen, hlen; 306 struct newesp *esp; 307 struct cryptodesc *crde; 308 struct cryptop *crp; 309 310 IPSEC_ASSERT(sav != NULL, ("null SA")); 311 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); 312 313 /* Valid IP Packet length ? */ 314 if ( (skip&3) || (m->m_pkthdr.len&3) ){ 315 DPRINTF(("%s: misaligned packet, skip %u pkt len %u", 316 __func__, skip, m->m_pkthdr.len)); 317 ESPSTAT_INC(esps_badilen); 318 m_freem(m); 319 return EINVAL; 320 } 321 /* XXX don't pullup, just copy header */ 322 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 323 324 esph = sav->tdb_authalgxform; 325 espx = sav->tdb_encalgxform; 326 327 /* Determine the ESP header and auth length */ 328 if (sav->flags & SADB_X_EXT_OLD) 329 hlen = sizeof (struct esp) + sav->ivlen; 330 else 331 hlen = sizeof (struct newesp) + sav->ivlen; 332 333 alen = xform_ah_authsize(esph); 334 335 /* 336 * Verify payload length is multiple of encryption algorithm 337 * block size. 338 * 339 * NB: This works for the null algorithm because the blocksize 340 * is 4 and all packets must be 4-byte aligned regardless 341 * of the algorithm. 342 */ 343 plen = m->m_pkthdr.len - (skip + hlen + alen); 344 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 345 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 346 " SA %s/%08lx\n", __func__, plen, espx->blocksize, 347 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 348 (u_long)ntohl(sav->spi))); 349 ESPSTAT_INC(esps_badilen); 350 m_freem(m); 351 return EINVAL; 352 } 353 354 /* 355 * Check sequence number. 356 */ 357 if (esph != NULL && sav->replay != NULL && 358 !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) { 359 DPRINTF(("%s: packet replay check for %s\n", __func__, 360 ipsec_logsastr(sav, buf, sizeof(buf)))); /*XXX*/ 361 ESPSTAT_INC(esps_replay); 362 m_freem(m); 363 return ENOBUFS; /*XXX*/ 364 } 365 366 /* Update the counters */ 367 ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen)); 368 369 /* Get crypto descriptors */ 370 crp = crypto_getreq(esph && espx ? 2 : 1); 371 if (crp == NULL) { 372 DPRINTF(("%s: failed to acquire crypto descriptors\n", 373 __func__)); 374 ESPSTAT_INC(esps_crypto); 375 m_freem(m); 376 return ENOBUFS; 377 } 378 379 /* Get IPsec-specific opaque pointer */ 380 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen, 381 M_XDATA, M_NOWAIT | M_ZERO); 382 if (tc == NULL) { 383 crypto_freereq(crp); 384 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 385 ESPSTAT_INC(esps_crypto); 386 m_freem(m); 387 return ENOBUFS; 388 } 389 390 if (esph != NULL) { 391 struct cryptodesc *crda = crp->crp_desc; 392 393 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor")); 394 395 /* Authentication descriptor */ 396 crda->crd_skip = skip; 397 if (SAV_ISGCM(sav)) 398 crda->crd_len = 8; /* RFC4106 5, SPI + SN */ 399 else 400 crda->crd_len = m->m_pkthdr.len - (skip + alen); 401 crda->crd_inject = m->m_pkthdr.len - alen; 402 403 crda->crd_alg = esph->type; 404 405 /* Copy the authenticator */ 406 m_copydata(m, m->m_pkthdr.len - alen, alen, 407 (caddr_t) (tc + 1)); 408 409 /* Chain authentication request */ 410 crde = crda->crd_next; 411 } else { 412 crde = crp->crp_desc; 413 } 414 415 /* Crypto operation descriptor */ 416 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 417 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 418 crp->crp_buf = (caddr_t) m; 419 crp->crp_callback = esp_input_cb; 420 crp->crp_sid = sav->tdb_cryptoid; 421 crp->crp_opaque = (caddr_t) tc; 422 423 /* These are passed as-is to the callback */ 424 tc->tc_spi = sav->spi; 425 tc->tc_dst = sav->sah->saidx.dst; 426 tc->tc_proto = sav->sah->saidx.proto; 427 tc->tc_protoff = protoff; 428 tc->tc_skip = skip; 429 KEY_ADDREFSA(sav); 430 tc->tc_sav = sav; 431 432 /* Decryption descriptor */ 433 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor")); 434 crde->crd_skip = skip + hlen; 435 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 436 crde->crd_inject = skip + hlen - sav->ivlen; 437 438 if (SAV_ISCTRORGCM(sav)) { 439 ivp = &crde->crd_iv[0]; 440 441 /* GCM IV Format: RFC4106 4 */ 442 /* CTR IV Format: RFC3686 4 */ 443 /* Salt is last four bytes of key, RFC4106 8.1 */ 444 /* Nonce is last four bytes of key, RFC3686 5.1 */ 445 memcpy(ivp, sav->key_enc->key_data + 446 _KEYLEN(sav->key_enc) - 4, 4); 447 448 if (SAV_ISCTR(sav)) { 449 /* Initial block counter is 1, RFC3686 4 */ 450 be32enc(&ivp[sav->ivlen + 4], 1); 451 } 452 453 m_copydata(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); 454 crde->crd_flags |= CRD_F_IV_EXPLICIT; 455 } 456 457 crde->crd_alg = espx->type; 458 459 return (crypto_dispatch(crp)); 460 } 461 462 /* 463 * ESP input callback from the crypto driver. 464 */ 465 static int 466 esp_input_cb(struct cryptop *crp) 467 { 468 char buf[128]; 469 u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN]; 470 int hlen, skip, protoff, error, alen; 471 struct mbuf *m; 472 struct cryptodesc *crd; 473 struct auth_hash *esph; 474 struct enc_xform *espx; 475 struct tdb_crypto *tc; 476 struct secasvar *sav; 477 struct secasindex *saidx; 478 caddr_t ptr; 479 480 crd = crp->crp_desc; 481 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!")); 482 483 tc = (struct tdb_crypto *) crp->crp_opaque; 484 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!")); 485 skip = tc->tc_skip; 486 protoff = tc->tc_protoff; 487 m = (struct mbuf *) crp->crp_buf; 488 489 sav = tc->tc_sav; 490 IPSEC_ASSERT(sav != NULL, ("null SA!")); 491 492 saidx = &sav->sah->saidx; 493 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 494 saidx->dst.sa.sa_family == AF_INET6, 495 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 496 497 esph = sav->tdb_authalgxform; 498 espx = sav->tdb_encalgxform; 499 500 /* Check for crypto errors */ 501 if (crp->crp_etype) { 502 /* Reset the session ID */ 503 if (sav->tdb_cryptoid != 0) 504 sav->tdb_cryptoid = crp->crp_sid; 505 506 if (crp->crp_etype == EAGAIN) 507 return (crypto_dispatch(crp)); 508 509 ESPSTAT_INC(esps_noxform); 510 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 511 error = crp->crp_etype; 512 goto bad; 513 } 514 515 /* Shouldn't happen... */ 516 if (m == NULL) { 517 ESPSTAT_INC(esps_crypto); 518 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 519 error = EINVAL; 520 goto bad; 521 } 522 ESPSTAT_INC(esps_hist[sav->alg_enc]); 523 524 /* If authentication was performed, check now. */ 525 if (esph != NULL) { 526 alen = xform_ah_authsize(esph); 527 AHSTAT_INC(ahs_hist[sav->alg_auth]); 528 /* Copy the authenticator from the packet */ 529 m_copydata(m, m->m_pkthdr.len - alen, alen, aalg); 530 ptr = (caddr_t) (tc + 1); 531 532 /* Verify authenticator */ 533 if (timingsafe_bcmp(ptr, aalg, alen) != 0) { 534 DPRINTF(("%s: authentication hash mismatch for " 535 "packet in SA %s/%08lx\n", __func__, 536 ipsec_address(&saidx->dst, buf, sizeof(buf)), 537 (u_long) ntohl(sav->spi))); 538 ESPSTAT_INC(esps_badauth); 539 error = EACCES; 540 goto bad; 541 } 542 543 /* Remove trailing authenticator */ 544 m_adj(m, -alen); 545 } 546 547 /* Release the crypto descriptors */ 548 free(tc, M_XDATA), tc = NULL; 549 crypto_freereq(crp), crp = NULL; 550 551 /* 552 * Packet is now decrypted. 553 */ 554 m->m_flags |= M_DECRYPTED; 555 556 /* 557 * Update replay sequence number, if appropriate. 558 */ 559 if (sav->replay) { 560 u_int32_t seq; 561 562 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 563 sizeof (seq), (caddr_t) &seq); 564 if (ipsec_updatereplay(ntohl(seq), sav)) { 565 DPRINTF(("%s: packet replay check for %s\n", __func__, 566 ipsec_logsastr(sav, buf, sizeof(buf)))); 567 ESPSTAT_INC(esps_replay); 568 error = ENOBUFS; 569 goto bad; 570 } 571 } 572 573 /* Determine the ESP header length */ 574 if (sav->flags & SADB_X_EXT_OLD) 575 hlen = sizeof (struct esp) + sav->ivlen; 576 else 577 hlen = sizeof (struct newesp) + sav->ivlen; 578 579 /* Remove the ESP header and IV from the mbuf. */ 580 error = m_striphdr(m, skip, hlen); 581 if (error) { 582 ESPSTAT_INC(esps_hdrops); 583 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 584 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 585 (u_long) ntohl(sav->spi))); 586 goto bad; 587 } 588 589 /* Save the last three bytes of decrypted data */ 590 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 591 592 /* Verify pad length */ 593 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 594 ESPSTAT_INC(esps_badilen); 595 DPRINTF(("%s: invalid padding length %d for %u byte packet " 596 "in SA %s/%08lx\n", __func__, lastthree[1], 597 m->m_pkthdr.len - skip, 598 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 599 (u_long) ntohl(sav->spi))); 600 error = EINVAL; 601 goto bad; 602 } 603 604 /* Verify correct decryption by checking the last padding bytes */ 605 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 606 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 607 ESPSTAT_INC(esps_badenc); 608 DPRINTF(("%s: decryption failed for packet in " 609 "SA %s/%08lx\n", __func__, ipsec_address( 610 &sav->sah->saidx.dst, buf, sizeof(buf)), 611 (u_long) ntohl(sav->spi))); 612 error = EINVAL; 613 goto bad; 614 } 615 } 616 617 /* Trim the mbuf chain to remove trailing authenticator and padding */ 618 m_adj(m, -(lastthree[1] + 2)); 619 620 /* Restore the Next Protocol field */ 621 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 622 623 switch (saidx->dst.sa.sa_family) { 624 #ifdef INET6 625 case AF_INET6: 626 error = ipsec6_common_input_cb(m, sav, skip, protoff); 627 break; 628 #endif 629 #ifdef INET 630 case AF_INET: 631 error = ipsec4_common_input_cb(m, sav, skip, protoff); 632 break; 633 #endif 634 default: 635 panic("%s: Unexpected address family: %d saidx=%p", __func__, 636 saidx->dst.sa.sa_family, saidx); 637 } 638 639 KEY_FREESAV(&sav); 640 return error; 641 bad: 642 if (sav) 643 KEY_FREESAV(&sav); 644 if (m != NULL) 645 m_freem(m); 646 if (tc != NULL) 647 free(tc, M_XDATA); 648 if (crp != NULL) 649 crypto_freereq(crp); 650 return error; 651 } 652 653 /* 654 * ESP output routine, called by ipsec[46]_process_packet(). 655 */ 656 static int 657 esp_output(struct mbuf *m, struct ipsecrequest *isr, struct mbuf **mp, 658 int skip, int protoff) 659 { 660 char buf[INET6_ADDRSTRLEN]; 661 struct enc_xform *espx; 662 struct auth_hash *esph; 663 uint8_t *ivp; 664 uint64_t cntr; 665 int hlen, rlen, padding, blks, alen, i, roff; 666 struct mbuf *mo = (struct mbuf *) NULL; 667 struct tdb_crypto *tc; 668 struct secasvar *sav; 669 struct secasindex *saidx; 670 unsigned char *pad; 671 u_int8_t prot; 672 int error, maxpacketsize; 673 674 struct cryptodesc *crde = NULL, *crda = NULL; 675 struct cryptop *crp; 676 677 sav = isr->sav; 678 IPSEC_ASSERT(sav != NULL, ("null SA")); 679 esph = sav->tdb_authalgxform; 680 espx = sav->tdb_encalgxform; 681 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 682 683 if (sav->flags & SADB_X_EXT_OLD) 684 hlen = sizeof (struct esp) + sav->ivlen; 685 else 686 hlen = sizeof (struct newesp) + sav->ivlen; 687 688 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 689 /* 690 * RFC4303 2.4 Requires 4 byte alignment. 691 */ 692 blks = MAX(4, espx->blocksize); /* Cipher blocksize */ 693 694 /* XXX clamp padding length a la KAME??? */ 695 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 696 697 alen = xform_ah_authsize(esph); 698 699 ESPSTAT_INC(esps_output); 700 701 saidx = &sav->sah->saidx; 702 /* Check for maximum packet size violations. */ 703 switch (saidx->dst.sa.sa_family) { 704 #ifdef INET 705 case AF_INET: 706 maxpacketsize = IP_MAXPACKET; 707 break; 708 #endif /* INET */ 709 #ifdef INET6 710 case AF_INET6: 711 maxpacketsize = IPV6_MAXPACKET; 712 break; 713 #endif /* INET6 */ 714 default: 715 DPRINTF(("%s: unknown/unsupported protocol " 716 "family %d, SA %s/%08lx\n", __func__, 717 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst, 718 buf, sizeof(buf)), (u_long) ntohl(sav->spi))); 719 ESPSTAT_INC(esps_nopf); 720 error = EPFNOSUPPORT; 721 goto bad; 722 } 723 DPRINTF(("%s: skip %d hlen %d rlen %d padding %d alen %d blksd %d\n", 724 __func__, skip, hlen, rlen, padding, alen, blks)); 725 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 726 DPRINTF(("%s: packet in SA %s/%08lx got too big " 727 "(len %u, max len %u)\n", __func__, 728 ipsec_address(&saidx->dst, buf, sizeof(buf)), 729 (u_long) ntohl(sav->spi), 730 skip + hlen + rlen + padding + alen, maxpacketsize)); 731 ESPSTAT_INC(esps_toobig); 732 error = EMSGSIZE; 733 goto bad; 734 } 735 736 /* Update the counters. */ 737 ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip); 738 739 m = m_unshare(m, M_NOWAIT); 740 if (m == NULL) { 741 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 742 ipsec_address(&saidx->dst, buf, sizeof(buf)), 743 (u_long) ntohl(sav->spi))); 744 ESPSTAT_INC(esps_hdrops); 745 error = ENOBUFS; 746 goto bad; 747 } 748 749 /* Inject ESP header. */ 750 mo = m_makespace(m, skip, hlen, &roff); 751 if (mo == NULL) { 752 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 753 __func__, hlen, ipsec_address(&saidx->dst, buf, 754 sizeof(buf)), (u_long) ntohl(sav->spi))); 755 ESPSTAT_INC(esps_hdrops); /* XXX diffs from openbsd */ 756 error = ENOBUFS; 757 goto bad; 758 } 759 760 /* Initialize ESP header. */ 761 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t)); 762 if (sav->replay) { 763 u_int32_t replay; 764 765 #ifdef REGRESSION 766 /* Emulate replay attack when ipsec_replay is TRUE. */ 767 if (!V_ipsec_replay) 768 #endif 769 sav->replay->count++; 770 replay = htonl(sav->replay->count); 771 bcopy((caddr_t) &replay, 772 mtod(mo, caddr_t) + roff + sizeof(u_int32_t), 773 sizeof(u_int32_t)); 774 } 775 776 /* 777 * Add padding -- better to do it ourselves than use the crypto engine, 778 * although if/when we support compression, we'd have to do that. 779 */ 780 pad = (u_char *) m_pad(m, padding + alen); 781 if (pad == NULL) { 782 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 783 ipsec_address(&saidx->dst, buf, sizeof(buf)), 784 (u_long) ntohl(sav->spi))); 785 m = NULL; /* NB: free'd by m_pad */ 786 error = ENOBUFS; 787 goto bad; 788 } 789 790 /* 791 * Add padding: random, zero, or self-describing. 792 * XXX catch unexpected setting 793 */ 794 switch (sav->flags & SADB_X_EXT_PMASK) { 795 case SADB_X_EXT_PRAND: 796 (void) read_random(pad, padding - 2); 797 break; 798 case SADB_X_EXT_PZERO: 799 bzero(pad, padding - 2); 800 break; 801 case SADB_X_EXT_PSEQ: 802 for (i = 0; i < padding - 2; i++) 803 pad[i] = i+1; 804 break; 805 } 806 807 /* Fix padding length and Next Protocol in padding itself. */ 808 pad[padding - 2] = padding - 2; 809 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 810 811 /* Fix Next Protocol in IPv4/IPv6 header. */ 812 prot = IPPROTO_ESP; 813 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 814 815 /* Get crypto descriptors. */ 816 crp = crypto_getreq(esph != NULL ? 2 : 1); 817 if (crp == NULL) { 818 DPRINTF(("%s: failed to acquire crypto descriptors\n", 819 __func__)); 820 ESPSTAT_INC(esps_crypto); 821 error = ENOBUFS; 822 goto bad; 823 } 824 825 /* IPsec-specific opaque crypto info. */ 826 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 827 M_XDATA, M_NOWAIT|M_ZERO); 828 if (tc == NULL) { 829 crypto_freereq(crp); 830 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 831 ESPSTAT_INC(esps_crypto); 832 error = ENOBUFS; 833 goto bad; 834 } 835 836 crde = crp->crp_desc; 837 crda = crde->crd_next; 838 839 /* Encryption descriptor. */ 840 crde->crd_skip = skip + hlen; 841 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 842 crde->crd_flags = CRD_F_ENCRYPT; 843 crde->crd_inject = skip + hlen - sav->ivlen; 844 845 /* Encryption operation. */ 846 crde->crd_alg = espx->type; 847 if (SAV_ISCTRORGCM(sav)) { 848 ivp = &crde->crd_iv[0]; 849 850 /* GCM IV Format: RFC4106 4 */ 851 /* CTR IV Format: RFC3686 4 */ 852 /* Salt is last four bytes of key, RFC4106 8.1 */ 853 /* Nonce is last four bytes of key, RFC3686 5.1 */ 854 memcpy(ivp, sav->key_enc->key_data + 855 _KEYLEN(sav->key_enc) - 4, 4); 856 SECASVAR_LOCK(sav); 857 cntr = sav->cntr++; 858 SECASVAR_UNLOCK(sav); 859 be64enc(&ivp[4], cntr); 860 861 if (SAV_ISCTR(sav)) { 862 /* Initial block counter is 1, RFC3686 4 */ 863 be32enc(&ivp[sav->ivlen + 4], 1); 864 } 865 866 m_copyback(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); 867 crde->crd_flags |= CRD_F_IV_EXPLICIT|CRD_F_IV_PRESENT; 868 } 869 870 /* Callback parameters */ 871 key_addref(isr->sp); 872 tc->tc_isr = isr; 873 KEY_ADDREFSA(sav); 874 tc->tc_sav = sav; 875 tc->tc_spi = sav->spi; 876 tc->tc_dst = saidx->dst; 877 tc->tc_proto = saidx->proto; 878 879 /* Crypto operation descriptor. */ 880 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 881 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 882 crp->crp_buf = (caddr_t) m; 883 crp->crp_callback = esp_output_cb; 884 crp->crp_opaque = (caddr_t) tc; 885 crp->crp_sid = sav->tdb_cryptoid; 886 887 if (esph) { 888 /* Authentication descriptor. */ 889 crda->crd_alg = esph->type; 890 crda->crd_skip = skip; 891 if (SAV_ISGCM(sav)) 892 crda->crd_len = 8; /* RFC4106 5, SPI + SN */ 893 else 894 crda->crd_len = m->m_pkthdr.len - (skip + alen); 895 crda->crd_inject = m->m_pkthdr.len - alen; 896 } 897 898 return crypto_dispatch(crp); 899 bad: 900 if (m) 901 m_freem(m); 902 return (error); 903 } 904 905 /* 906 * ESP output callback from the crypto driver. 907 */ 908 static int 909 esp_output_cb(struct cryptop *crp) 910 { 911 char buf[INET6_ADDRSTRLEN]; 912 struct tdb_crypto *tc; 913 struct ipsecrequest *isr; 914 struct secasvar *sav; 915 struct mbuf *m; 916 int error; 917 918 tc = (struct tdb_crypto *) crp->crp_opaque; 919 IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); 920 m = (struct mbuf *) crp->crp_buf; 921 922 isr = tc->tc_isr; 923 IPSEC_ASSERT(isr->sp != NULL, ("NULL isr->sp")); 924 IPSECREQUEST_LOCK(isr); 925 sav = tc->tc_sav; 926 927 /* With the isr lock released, SA pointer may have changed. */ 928 if (sav != isr->sav) { 929 ESPSTAT_INC(esps_notdb); 930 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 931 __func__, ipsec_address(&tc->tc_dst, buf, sizeof(buf)), 932 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 933 error = ENOBUFS; /*XXX*/ 934 goto bad; 935 } 936 937 /* Check for crypto errors. */ 938 if (crp->crp_etype) { 939 /* Reset session ID. */ 940 if (sav->tdb_cryptoid != 0) 941 sav->tdb_cryptoid = crp->crp_sid; 942 943 if (crp->crp_etype == EAGAIN) { 944 IPSECREQUEST_UNLOCK(isr); 945 return (crypto_dispatch(crp)); 946 } 947 948 ESPSTAT_INC(esps_noxform); 949 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 950 error = crp->crp_etype; 951 goto bad; 952 } 953 954 /* Shouldn't happen... */ 955 if (m == NULL) { 956 ESPSTAT_INC(esps_crypto); 957 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 958 error = EINVAL; 959 goto bad; 960 } 961 ESPSTAT_INC(esps_hist[sav->alg_enc]); 962 if (sav->tdb_authalgxform != NULL) 963 AHSTAT_INC(ahs_hist[sav->alg_auth]); 964 965 /* Release crypto descriptors. */ 966 free(tc, M_XDATA); 967 crypto_freereq(crp); 968 969 #ifdef REGRESSION 970 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 971 if (V_ipsec_integrity) { 972 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN]; 973 struct auth_hash *esph; 974 975 /* 976 * Corrupt HMAC if we want to test integrity verification of 977 * the other side. 978 */ 979 esph = sav->tdb_authalgxform; 980 if (esph != NULL) { 981 int alen; 982 983 alen = xform_ah_authsize(esph); 984 m_copyback(m, m->m_pkthdr.len - alen, 985 alen, ipseczeroes); 986 } 987 } 988 #endif 989 990 /* NB: m is reclaimed by ipsec_process_done. */ 991 error = ipsec_process_done(m, isr); 992 KEY_FREESAV(&sav); 993 IPSECREQUEST_UNLOCK(isr); 994 KEY_FREESP(&isr->sp); 995 return (error); 996 bad: 997 if (sav) 998 KEY_FREESAV(&sav); 999 IPSECREQUEST_UNLOCK(isr); 1000 KEY_FREESP(&isr->sp); 1001 if (m) 1002 m_freem(m); 1003 free(tc, M_XDATA); 1004 crypto_freereq(crp); 1005 return (error); 1006 } 1007 1008 static struct xformsw esp_xformsw = { 1009 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 1010 esp_init, esp_zeroize, esp_input, 1011 esp_output 1012 }; 1013 1014 static void 1015 esp_attach(void) 1016 { 1017 1018 xform_register(&esp_xformsw); 1019 } 1020 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL);
Cache object: 974f37dea40f8f31ad101a10bc10d10d
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