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 52 #include <net/if.h> 53 #include <net/vnet.h> 54 55 #include <netinet/in.h> 56 #include <netinet/in_systm.h> 57 #include <netinet/ip.h> 58 #include <netinet/ip_ecn.h> 59 #include <netinet/ip6.h> 60 61 #include <netipsec/ipsec.h> 62 #include <netipsec/ah.h> 63 #include <netipsec/ah_var.h> 64 #include <netipsec/esp.h> 65 #include <netipsec/esp_var.h> 66 #include <netipsec/xform.h> 67 68 #ifdef INET6 69 #include <netinet6/ip6_var.h> 70 #include <netipsec/ipsec6.h> 71 #include <netinet6/ip6_ecn.h> 72 #endif 73 74 #include <netipsec/key.h> 75 #include <netipsec/key_debug.h> 76 77 #include <opencrypto/cryptodev.h> 78 #include <opencrypto/xform.h> 79 80 VNET_DEFINE(int, esp_enable) = 1; 81 VNET_PCPUSTAT_DEFINE(struct espstat, espstat); 82 VNET_PCPUSTAT_SYSINIT(espstat); 83 84 #ifdef VIMAGE 85 VNET_PCPUSTAT_SYSUNINIT(espstat); 86 #endif /* VIMAGE */ 87 88 SYSCTL_DECL(_net_inet_esp); 89 SYSCTL_INT(_net_inet_esp, OID_AUTO, esp_enable, 90 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(esp_enable), 0, ""); 91 SYSCTL_VNET_PCPUSTAT(_net_inet_esp, IPSECCTL_STATS, stats, 92 struct espstat, espstat, 93 "ESP statistics (struct espstat, netipsec/esp_var.h"); 94 95 static int esp_input_cb(struct cryptop *op); 96 static int esp_output_cb(struct cryptop *crp); 97 98 /* 99 * NB: this is public for use by the PF_KEY support. 100 * NB: if you add support here; be sure to add code to esp_attach below! 101 */ 102 struct enc_xform * 103 esp_algorithm_lookup(int alg) 104 { 105 if (alg >= ESP_ALG_MAX) 106 return NULL; 107 switch (alg) { 108 case SADB_EALG_DESCBC: 109 return &enc_xform_des; 110 case SADB_EALG_3DESCBC: 111 return &enc_xform_3des; 112 case SADB_X_EALG_AES: 113 return &enc_xform_rijndael128; 114 case SADB_X_EALG_BLOWFISHCBC: 115 return &enc_xform_blf; 116 case SADB_X_EALG_CAST128CBC: 117 return &enc_xform_cast5; 118 case SADB_X_EALG_SKIPJACK: 119 return &enc_xform_skipjack; 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)) == SADB_X_EXT_IV4B) { 188 DPRINTF(("%s: 4-byte IV not supported with protocol\n", 189 __func__)); 190 return EINVAL; 191 } 192 keylen = _KEYLEN(sav->key_enc); 193 if (txform->minkey > keylen || keylen > txform->maxkey) { 194 DPRINTF(("%s: invalid key length %u, must be in the range " 195 "[%u..%u] for algorithm %s\n", __func__, 196 keylen, txform->minkey, txform->maxkey, 197 txform->name)); 198 return EINVAL; 199 } 200 201 /* 202 * NB: The null xform needs a non-zero blocksize to keep the 203 * crypto code happy but if we use it to set ivlen then 204 * the ESP header will be processed incorrectly. The 205 * compromise is to force it to zero here. 206 */ 207 sav->ivlen = (txform == &enc_xform_null ? 0 : txform->ivsize); 208 sav->iv = (caddr_t) malloc(sav->ivlen, M_XDATA, M_WAITOK); 209 key_randomfill(sav->iv, sav->ivlen); /*XXX*/ 210 211 /* 212 * Setup AH-related state. 213 */ 214 if (sav->alg_auth != 0) { 215 error = ah_init0(sav, xsp, &cria); 216 if (error) 217 return error; 218 } 219 220 /* NB: override anything set in ah_init0 */ 221 sav->tdb_xform = xsp; 222 sav->tdb_encalgxform = txform; 223 224 /* 225 * Whenever AES-GCM is used for encryption, one 226 * of the AES authentication algorithms is chosen 227 * as well, based on the key size. 228 */ 229 if (sav->alg_enc == SADB_X_EALG_AESGCM16) { 230 switch (keylen) { 231 case AES_128_HMAC_KEY_LEN: 232 sav->alg_auth = SADB_X_AALG_AES128GMAC; 233 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_128; 234 break; 235 case AES_192_HMAC_KEY_LEN: 236 sav->alg_auth = SADB_X_AALG_AES192GMAC; 237 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_192; 238 break; 239 case AES_256_HMAC_KEY_LEN: 240 sav->alg_auth = SADB_X_AALG_AES256GMAC; 241 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_256; 242 break; 243 default: 244 DPRINTF(("%s: invalid key length %u" 245 "for algorithm %s\n", __func__, 246 keylen, txform->name)); 247 return EINVAL; 248 } 249 bzero(&cria, sizeof(cria)); 250 cria.cri_alg = sav->tdb_authalgxform->type; 251 cria.cri_klen = _KEYBITS(sav->key_enc) + 4; 252 cria.cri_key = sav->key_enc->key_data; 253 } 254 255 /* Initialize crypto session. */ 256 bzero(&crie, sizeof (crie)); 257 crie.cri_alg = sav->tdb_encalgxform->type; 258 crie.cri_klen = _KEYBITS(sav->key_enc); 259 crie.cri_key = sav->key_enc->key_data; 260 if (sav->alg_enc == SADB_X_EALG_AESGCM16) 261 arc4rand(crie.cri_iv, sav->ivlen, 0); 262 263 /* XXX Rounds ? */ 264 265 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 266 /* init both auth & enc */ 267 crie.cri_next = &cria; 268 error = crypto_newsession(&sav->tdb_cryptoid, 269 &crie, V_crypto_support); 270 } else if (sav->tdb_encalgxform) { 271 error = crypto_newsession(&sav->tdb_cryptoid, 272 &crie, V_crypto_support); 273 } else if (sav->tdb_authalgxform) { 274 error = crypto_newsession(&sav->tdb_cryptoid, 275 &cria, V_crypto_support); 276 } else { 277 /* XXX cannot happen? */ 278 DPRINTF(("%s: no encoding OR authentication xform!\n", 279 __func__)); 280 error = EINVAL; 281 } 282 return error; 283 } 284 285 /* 286 * Paranoia. 287 */ 288 static int 289 esp_zeroize(struct secasvar *sav) 290 { 291 /* NB: ah_zerorize free's the crypto session state */ 292 int error = ah_zeroize(sav); 293 294 if (sav->key_enc) 295 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc)); 296 if (sav->iv) { 297 free(sav->iv, M_XDATA); 298 sav->iv = NULL; 299 } 300 sav->tdb_encalgxform = NULL; 301 sav->tdb_xform = NULL; 302 return error; 303 } 304 305 /* 306 * ESP input processing, called (eventually) through the protocol switch. 307 */ 308 static int 309 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 310 { 311 char buf[128]; 312 struct auth_hash *esph; 313 struct enc_xform *espx; 314 struct tdb_crypto *tc; 315 int plen, alen, hlen; 316 struct newesp *esp; 317 struct cryptodesc *crde; 318 struct cryptop *crp; 319 320 IPSEC_ASSERT(sav != NULL, ("null SA")); 321 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); 322 323 alen = 0; 324 /* Valid IP Packet length ? */ 325 if ( (skip&3) || (m->m_pkthdr.len&3) ){ 326 DPRINTF(("%s: misaligned packet, skip %u pkt len %u", 327 __func__, skip, m->m_pkthdr.len)); 328 ESPSTAT_INC(esps_badilen); 329 m_freem(m); 330 return EINVAL; 331 } 332 /* XXX don't pullup, just copy header */ 333 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 334 335 esph = sav->tdb_authalgxform; 336 espx = sav->tdb_encalgxform; 337 338 /* Determine the ESP header length */ 339 if (sav->flags & SADB_X_EXT_OLD) 340 hlen = sizeof (struct esp) + sav->ivlen; 341 else 342 hlen = sizeof (struct newesp) + sav->ivlen; 343 /* Authenticator hash size */ 344 alen = esph ? esph->hashsize : 0; 345 346 /* 347 * Verify payload length is multiple of encryption algorithm 348 * block size. 349 * 350 * NB: This works for the null algorithm because the blocksize 351 * is 4 and all packets must be 4-byte aligned regardless 352 * of the algorithm. 353 */ 354 plen = m->m_pkthdr.len - (skip + hlen + alen); 355 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 356 if (!espx || sav->alg_enc != SADB_X_EALG_AESGCM16) { 357 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 358 " SA %s/%08lx\n", __func__, 359 plen, espx->blocksize, ipsec_address(&sav->sah->saidx.dst, 360 buf, sizeof(buf)), (u_long) ntohl(sav->spi))); 361 ESPSTAT_INC(esps_badilen); 362 m_freem(m); 363 return EINVAL; 364 } 365 } 366 367 /* 368 * Check sequence number. 369 */ 370 if (esph != NULL && sav->replay != NULL && 371 !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) { 372 DPRINTF(("%s: packet replay check for %s\n", __func__, 373 ipsec_logsastr(sav, buf, sizeof(buf)))); /*XXX*/ 374 ESPSTAT_INC(esps_replay); 375 m_freem(m); 376 return ENOBUFS; /*XXX*/ 377 } 378 379 /* Update the counters */ 380 ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen)); 381 382 /* Get crypto descriptors */ 383 crp = crypto_getreq(esph && espx ? 2 : 1); 384 if (crp == NULL) { 385 DPRINTF(("%s: failed to acquire crypto descriptors\n", 386 __func__)); 387 ESPSTAT_INC(esps_crypto); 388 m_freem(m); 389 return ENOBUFS; 390 } 391 392 /* Get IPsec-specific opaque pointer */ 393 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen, 394 M_XDATA, M_NOWAIT | M_ZERO); 395 if (tc == NULL) { 396 crypto_freereq(crp); 397 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 398 ESPSTAT_INC(esps_crypto); 399 m_freem(m); 400 return ENOBUFS; 401 } 402 403 if (esph != NULL) { 404 struct cryptodesc *crda = crp->crp_desc; 405 406 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor")); 407 408 /* Authentication descriptor */ 409 crda->crd_skip = skip; 410 if (espx && espx->type == CRYPTO_AES_NIST_GCM_16) 411 crda->crd_len = hlen - sav->ivlen; 412 else 413 crda->crd_len = m->m_pkthdr.len - (skip + alen); 414 crda->crd_inject = m->m_pkthdr.len - alen; 415 416 crda->crd_alg = esph->type; 417 if (espx && (espx->type == CRYPTO_AES_NIST_GCM_16)) { 418 crda->crd_key = sav->key_enc->key_data; 419 crda->crd_klen = _KEYBITS(sav->key_enc); 420 } else { 421 crda->crd_key = sav->key_auth->key_data; 422 crda->crd_klen = _KEYBITS(sav->key_auth); 423 } 424 425 /* Copy the authenticator */ 426 m_copydata(m, m->m_pkthdr.len - alen, alen, 427 (caddr_t) (tc + 1)); 428 429 /* Chain authentication request */ 430 crde = crda->crd_next; 431 } else { 432 crde = crp->crp_desc; 433 } 434 435 /* Crypto operation descriptor */ 436 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 437 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 438 crp->crp_buf = (caddr_t) m; 439 crp->crp_callback = esp_input_cb; 440 crp->crp_sid = sav->tdb_cryptoid; 441 crp->crp_opaque = (caddr_t) tc; 442 443 /* These are passed as-is to the callback */ 444 tc->tc_spi = sav->spi; 445 tc->tc_dst = sav->sah->saidx.dst; 446 tc->tc_proto = sav->sah->saidx.proto; 447 tc->tc_protoff = protoff; 448 tc->tc_skip = skip; 449 KEY_ADDREFSA(sav); 450 tc->tc_sav = sav; 451 452 /* Decryption descriptor */ 453 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor")); 454 crde->crd_skip = skip + hlen; 455 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 456 crde->crd_inject = skip + hlen - sav->ivlen; 457 458 crde->crd_alg = espx->type; 459 crde->crd_key = sav->key_enc->key_data; 460 crde->crd_klen = _KEYBITS(sav->key_enc); 461 if (espx && (espx->type == CRYPTO_AES_NIST_GCM_16)) 462 crde->crd_flags |= CRD_F_IV_EXPLICIT; 463 464 /* XXX Rounds ? */ 465 466 return (crypto_dispatch(crp)); 467 } 468 469 /* 470 * ESP input callback from the crypto driver. 471 */ 472 static int 473 esp_input_cb(struct cryptop *crp) 474 { 475 char buf[128]; 476 u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN]; 477 int hlen, skip, protoff, error, alen; 478 struct mbuf *m; 479 struct cryptodesc *crd; 480 struct auth_hash *esph; 481 struct enc_xform *espx; 482 struct tdb_crypto *tc; 483 struct secasvar *sav; 484 struct secasindex *saidx; 485 caddr_t ptr; 486 487 crd = crp->crp_desc; 488 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!")); 489 490 tc = (struct tdb_crypto *) crp->crp_opaque; 491 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!")); 492 skip = tc->tc_skip; 493 protoff = tc->tc_protoff; 494 m = (struct mbuf *) crp->crp_buf; 495 496 sav = tc->tc_sav; 497 IPSEC_ASSERT(sav != NULL, ("null SA!")); 498 499 saidx = &sav->sah->saidx; 500 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 501 saidx->dst.sa.sa_family == AF_INET6, 502 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 503 504 esph = sav->tdb_authalgxform; 505 espx = sav->tdb_encalgxform; 506 507 /* Check for crypto errors */ 508 if (crp->crp_etype) { 509 /* Reset the session ID */ 510 if (sav->tdb_cryptoid != 0) 511 sav->tdb_cryptoid = crp->crp_sid; 512 513 if (crp->crp_etype == EAGAIN) 514 return (crypto_dispatch(crp)); 515 516 ESPSTAT_INC(esps_noxform); 517 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 518 error = crp->crp_etype; 519 goto bad; 520 } 521 522 /* Shouldn't happen... */ 523 if (m == NULL) { 524 ESPSTAT_INC(esps_crypto); 525 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 526 error = EINVAL; 527 goto bad; 528 } 529 ESPSTAT_INC(esps_hist[sav->alg_enc]); 530 531 /* If authentication was performed, check now. */ 532 if (esph != NULL) { 533 alen = esph->hashsize; 534 AHSTAT_INC(ahs_hist[sav->alg_auth]); 535 /* Copy the authenticator from the packet */ 536 m_copydata(m, m->m_pkthdr.len - alen, alen, aalg); 537 ptr = (caddr_t) (tc + 1); 538 539 /* Verify authenticator */ 540 if (bcmp(ptr, aalg, alen) != 0) { 541 DPRINTF(("%s: authentication hash mismatch for " 542 "packet in SA %s/%08lx\n", __func__, 543 ipsec_address(&saidx->dst, buf, sizeof(buf)), 544 (u_long) ntohl(sav->spi))); 545 ESPSTAT_INC(esps_badauth); 546 error = EACCES; 547 goto bad; 548 } 549 550 /* Remove trailing authenticator */ 551 m_adj(m, -alen); 552 } 553 554 /* Release the crypto descriptors */ 555 free(tc, M_XDATA), tc = NULL; 556 crypto_freereq(crp), crp = NULL; 557 558 /* 559 * Packet is now decrypted. 560 */ 561 m->m_flags |= M_DECRYPTED; 562 563 /* 564 * Update replay sequence number, if appropriate. 565 */ 566 if (sav->replay) { 567 u_int32_t seq; 568 569 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 570 sizeof (seq), (caddr_t) &seq); 571 if (ipsec_updatereplay(ntohl(seq), sav)) { 572 DPRINTF(("%s: packet replay check for %s\n", __func__, 573 ipsec_logsastr(sav, buf, sizeof(buf)))); 574 ESPSTAT_INC(esps_replay); 575 error = ENOBUFS; 576 goto bad; 577 } 578 } 579 580 /* Determine the ESP header length */ 581 if (sav->flags & SADB_X_EXT_OLD) 582 hlen = sizeof (struct esp) + sav->ivlen; 583 else 584 hlen = sizeof (struct newesp) + sav->ivlen; 585 586 /* Remove the ESP header and IV from the mbuf. */ 587 error = m_striphdr(m, skip, hlen); 588 if (error) { 589 ESPSTAT_INC(esps_hdrops); 590 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 591 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 592 (u_long) ntohl(sav->spi))); 593 goto bad; 594 } 595 596 /* Save the last three bytes of decrypted data */ 597 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 598 599 /* Verify pad length */ 600 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 601 ESPSTAT_INC(esps_badilen); 602 DPRINTF(("%s: invalid padding length %d for %u byte packet " 603 "in SA %s/%08lx\n", __func__, lastthree[1], 604 m->m_pkthdr.len - skip, 605 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 606 (u_long) ntohl(sav->spi))); 607 error = EINVAL; 608 goto bad; 609 } 610 611 /* Verify correct decryption by checking the last padding bytes */ 612 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 613 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 614 ESPSTAT_INC(esps_badenc); 615 DPRINTF(("%s: decryption failed for packet in " 616 "SA %s/%08lx\n", __func__, ipsec_address( 617 &sav->sah->saidx.dst, buf, sizeof(buf)), 618 (u_long) ntohl(sav->spi))); 619 error = EINVAL; 620 goto bad; 621 } 622 } 623 624 /* Trim the mbuf chain to remove trailing authenticator and padding */ 625 m_adj(m, -(lastthree[1] + 2)); 626 627 /* Restore the Next Protocol field */ 628 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 629 630 switch (saidx->dst.sa.sa_family) { 631 #ifdef INET6 632 case AF_INET6: 633 error = ipsec6_common_input_cb(m, sav, skip, protoff); 634 break; 635 #endif 636 #ifdef INET 637 case AF_INET: 638 error = ipsec4_common_input_cb(m, sav, skip, protoff); 639 break; 640 #endif 641 default: 642 panic("%s: Unexpected address family: %d saidx=%p", __func__, 643 saidx->dst.sa.sa_family, saidx); 644 } 645 646 KEY_FREESAV(&sav); 647 return error; 648 bad: 649 if (sav) 650 KEY_FREESAV(&sav); 651 if (m != NULL) 652 m_freem(m); 653 if (tc != NULL) 654 free(tc, M_XDATA); 655 if (crp != NULL) 656 crypto_freereq(crp); 657 return error; 658 } 659 660 /* 661 * ESP output routine, called by ipsec[46]_process_packet(). 662 */ 663 static int 664 esp_output(struct mbuf *m, struct ipsecrequest *isr, struct mbuf **mp, 665 int skip, int protoff) 666 { 667 char buf[INET6_ADDRSTRLEN]; 668 struct enc_xform *espx; 669 struct auth_hash *esph; 670 int hlen, rlen, padding, blks, alen, i, roff; 671 struct mbuf *mo = (struct mbuf *) NULL; 672 struct tdb_crypto *tc; 673 struct secasvar *sav; 674 struct secasindex *saidx; 675 unsigned char *pad; 676 u_int8_t prot; 677 int error, maxpacketsize; 678 679 struct cryptodesc *crde = NULL, *crda = NULL; 680 struct cryptop *crp; 681 682 sav = isr->sav; 683 IPSEC_ASSERT(sav != NULL, ("null SA")); 684 esph = sav->tdb_authalgxform; 685 espx = sav->tdb_encalgxform; 686 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 687 688 if (sav->flags & SADB_X_EXT_OLD) 689 hlen = sizeof (struct esp) + sav->ivlen; 690 else 691 hlen = sizeof (struct newesp) + sav->ivlen; 692 693 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 694 /* 695 * NB: The null encoding transform has a blocksize of 4 696 * so that headers are properly aligned. 697 */ 698 blks = espx->ivsize; /* IV blocksize */ 699 700 /* XXX clamp padding length a la KAME??? */ 701 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 702 703 if (esph) 704 alen = esph->hashsize; 705 else 706 alen = 0; 707 708 ESPSTAT_INC(esps_output); 709 710 saidx = &sav->sah->saidx; 711 /* Check for maximum packet size violations. */ 712 switch (saidx->dst.sa.sa_family) { 713 #ifdef INET 714 case AF_INET: 715 maxpacketsize = IP_MAXPACKET; 716 break; 717 #endif /* INET */ 718 #ifdef INET6 719 case AF_INET6: 720 maxpacketsize = IPV6_MAXPACKET; 721 break; 722 #endif /* INET6 */ 723 default: 724 DPRINTF(("%s: unknown/unsupported protocol " 725 "family %d, SA %s/%08lx\n", __func__, 726 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst, 727 buf, sizeof(buf)), (u_long) ntohl(sav->spi))); 728 ESPSTAT_INC(esps_nopf); 729 error = EPFNOSUPPORT; 730 goto bad; 731 } 732 DPRINTF(("%s: skip %d hlen %d rlen %d padding %d alen %d blksd %d\n", 733 __func__, skip, hlen, rlen, padding, alen, blks)); 734 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 735 DPRINTF(("%s: packet in SA %s/%08lx got too big " 736 "(len %u, max len %u)\n", __func__, 737 ipsec_address(&saidx->dst, buf, sizeof(buf)), 738 (u_long) ntohl(sav->spi), 739 skip + hlen + rlen + padding + alen, maxpacketsize)); 740 ESPSTAT_INC(esps_toobig); 741 error = EMSGSIZE; 742 goto bad; 743 } 744 745 /* Update the counters. */ 746 ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip); 747 748 m = m_unshare(m, M_NOWAIT); 749 if (m == NULL) { 750 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 751 ipsec_address(&saidx->dst, buf, sizeof(buf)), 752 (u_long) ntohl(sav->spi))); 753 ESPSTAT_INC(esps_hdrops); 754 error = ENOBUFS; 755 goto bad; 756 } 757 758 /* Inject ESP header. */ 759 mo = m_makespace(m, skip, hlen, &roff); 760 if (mo == NULL) { 761 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 762 __func__, hlen, ipsec_address(&saidx->dst, buf, 763 sizeof(buf)), (u_long) ntohl(sav->spi))); 764 ESPSTAT_INC(esps_hdrops); /* XXX diffs from openbsd */ 765 error = ENOBUFS; 766 goto bad; 767 } 768 769 /* Initialize ESP header. */ 770 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t)); 771 if (sav->replay) { 772 u_int32_t replay; 773 774 #ifdef REGRESSION 775 /* Emulate replay attack when ipsec_replay is TRUE. */ 776 if (!V_ipsec_replay) 777 #endif 778 sav->replay->count++; 779 replay = htonl(sav->replay->count); 780 bcopy((caddr_t) &replay, 781 mtod(mo, caddr_t) + roff + sizeof(u_int32_t), 782 sizeof(u_int32_t)); 783 } 784 785 /* 786 * Add padding -- better to do it ourselves than use the crypto engine, 787 * although if/when we support compression, we'd have to do that. 788 */ 789 pad = (u_char *) m_pad(m, padding + alen); 790 if (pad == NULL) { 791 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 792 ipsec_address(&saidx->dst, buf, sizeof(buf)), 793 (u_long) ntohl(sav->spi))); 794 m = NULL; /* NB: free'd by m_pad */ 795 error = ENOBUFS; 796 goto bad; 797 } 798 799 /* 800 * Add padding: random, zero, or self-describing. 801 * XXX catch unexpected setting 802 */ 803 switch (sav->flags & SADB_X_EXT_PMASK) { 804 case SADB_X_EXT_PRAND: 805 (void) read_random(pad, padding - 2); 806 break; 807 case SADB_X_EXT_PZERO: 808 bzero(pad, padding - 2); 809 break; 810 case SADB_X_EXT_PSEQ: 811 for (i = 0; i < padding - 2; i++) 812 pad[i] = i+1; 813 break; 814 } 815 816 /* Fix padding length and Next Protocol in padding itself. */ 817 pad[padding - 2] = padding - 2; 818 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 819 820 /* Fix Next Protocol in IPv4/IPv6 header. */ 821 prot = IPPROTO_ESP; 822 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 823 824 /* Get crypto descriptors. */ 825 crp = crypto_getreq(esph && espx ? 2 : 1); 826 if (crp == NULL) { 827 DPRINTF(("%s: failed to acquire crypto descriptors\n", 828 __func__)); 829 ESPSTAT_INC(esps_crypto); 830 error = ENOBUFS; 831 goto bad; 832 } 833 834 if (espx) { 835 crde = crp->crp_desc; 836 crda = crde->crd_next; 837 838 /* Encryption descriptor. */ 839 crde->crd_skip = skip + hlen; 840 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 841 crde->crd_flags = CRD_F_ENCRYPT; 842 crde->crd_inject = skip + hlen - sav->ivlen; 843 844 /* Encryption operation. */ 845 crde->crd_alg = espx->type; 846 crde->crd_key = sav->key_enc->key_data; 847 crde->crd_klen = _KEYBITS(sav->key_enc); 848 if (espx->type == CRYPTO_AES_NIST_GCM_16) 849 crde->crd_flags |= CRD_F_IV_EXPLICIT; 850 /* XXX Rounds ? */ 851 } else 852 crda = crp->crp_desc; 853 854 /* IPsec-specific opaque crypto info. */ 855 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 856 M_XDATA, M_NOWAIT|M_ZERO); 857 if (tc == NULL) { 858 crypto_freereq(crp); 859 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 860 ESPSTAT_INC(esps_crypto); 861 error = ENOBUFS; 862 goto bad; 863 } 864 865 /* Callback parameters */ 866 tc->tc_isr = isr; 867 KEY_ADDREFSA(sav); 868 tc->tc_sav = sav; 869 tc->tc_spi = sav->spi; 870 tc->tc_dst = saidx->dst; 871 tc->tc_proto = saidx->proto; 872 873 /* Crypto operation descriptor. */ 874 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 875 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 876 crp->crp_buf = (caddr_t) m; 877 crp->crp_callback = esp_output_cb; 878 crp->crp_opaque = (caddr_t) tc; 879 crp->crp_sid = sav->tdb_cryptoid; 880 881 if (esph) { 882 /* Authentication descriptor. */ 883 crda->crd_skip = skip; 884 if (espx && espx->type == CRYPTO_AES_NIST_GCM_16) 885 crda->crd_len = hlen - sav->ivlen; 886 else 887 crda->crd_len = m->m_pkthdr.len - (skip + alen); 888 crda->crd_inject = m->m_pkthdr.len - alen; 889 890 /* Authentication operation. */ 891 crda->crd_alg = esph->type; 892 if (espx && espx->type == CRYPTO_AES_NIST_GCM_16) { 893 crda->crd_key = sav->key_enc->key_data; 894 crda->crd_klen = _KEYBITS(sav->key_enc); 895 } else { 896 crda->crd_key = sav->key_auth->key_data; 897 crda->crd_klen = _KEYBITS(sav->key_auth); 898 } 899 900 } 901 902 return crypto_dispatch(crp); 903 bad: 904 if (m) 905 m_freem(m); 906 return (error); 907 } 908 909 /* 910 * ESP output callback from the crypto driver. 911 */ 912 static int 913 esp_output_cb(struct cryptop *crp) 914 { 915 char buf[INET6_ADDRSTRLEN]; 916 struct tdb_crypto *tc; 917 struct ipsecrequest *isr; 918 struct secasvar *sav; 919 struct mbuf *m; 920 int error; 921 922 tc = (struct tdb_crypto *) crp->crp_opaque; 923 IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); 924 m = (struct mbuf *) crp->crp_buf; 925 926 isr = tc->tc_isr; 927 IPSEC_ASSERT(isr->sp != NULL, ("NULL isr->sp")); 928 IPSECREQUEST_LOCK(isr); 929 sav = tc->tc_sav; 930 /* With the isr lock released SA pointer can be updated. */ 931 if (sav != isr->sav) { 932 ESPSTAT_INC(esps_notdb); 933 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 934 __func__, ipsec_address(&tc->tc_dst, buf, sizeof(buf)), 935 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 936 error = ENOBUFS; /*XXX*/ 937 goto bad; 938 } 939 940 /* Check for crypto errors. */ 941 if (crp->crp_etype) { 942 /* Reset session ID. */ 943 if (sav->tdb_cryptoid != 0) 944 sav->tdb_cryptoid = crp->crp_sid; 945 946 if (crp->crp_etype == EAGAIN) { 947 IPSECREQUEST_UNLOCK(isr); 948 return (crypto_dispatch(crp)); 949 } 950 951 ESPSTAT_INC(esps_noxform); 952 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 953 error = crp->crp_etype; 954 goto bad; 955 } 956 957 /* Shouldn't happen... */ 958 if (m == NULL) { 959 ESPSTAT_INC(esps_crypto); 960 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 961 error = EINVAL; 962 goto bad; 963 } 964 ESPSTAT_INC(esps_hist[sav->alg_enc]); 965 if (sav->tdb_authalgxform != NULL) 966 AHSTAT_INC(ahs_hist[sav->alg_auth]); 967 968 /* Release crypto descriptors. */ 969 free(tc, M_XDATA); 970 crypto_freereq(crp); 971 972 #ifdef REGRESSION 973 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 974 if (V_ipsec_integrity) { 975 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN]; 976 struct auth_hash *esph; 977 978 /* 979 * Corrupt HMAC if we want to test integrity verification of 980 * the other side. 981 */ 982 esph = sav->tdb_authalgxform; 983 if (esph != NULL) { 984 int alen; 985 986 switch (esph->type) { 987 case CRYPTO_SHA2_256_HMAC: 988 case CRYPTO_SHA2_384_HMAC: 989 case CRYPTO_SHA2_512_HMAC: 990 alen = esph->hashsize/2; 991 break; 992 case CRYPTO_AES_128_NIST_GMAC: 993 case CRYPTO_AES_192_NIST_GMAC: 994 case CRYPTO_AES_256_NIST_GMAC: 995 alen = esph->hashsize; 996 break; 997 default: 998 alen = AH_HMAC_HASHLEN; 999 break; 1000 } 1001 m_copyback(m, m->m_pkthdr.len - alen, 1002 alen, ipseczeroes); 1003 } 1004 } 1005 #endif 1006 1007 /* NB: m is reclaimed by ipsec_process_done. */ 1008 error = ipsec_process_done(m, isr); 1009 KEY_FREESAV(&sav); 1010 IPSECREQUEST_UNLOCK(isr); 1011 KEY_FREESP(&isr->sp); 1012 return (error); 1013 bad: 1014 if (sav) 1015 KEY_FREESAV(&sav); 1016 IPSECREQUEST_UNLOCK(isr); 1017 KEY_FREESP(&isr->sp); 1018 if (m) 1019 m_freem(m); 1020 free(tc, M_XDATA); 1021 crypto_freereq(crp); 1022 return (error); 1023 } 1024 1025 static struct xformsw esp_xformsw = { 1026 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 1027 esp_init, esp_zeroize, esp_input, 1028 esp_output 1029 }; 1030 1031 static void 1032 esp_attach(void) 1033 { 1034 1035 xform_register(&esp_xformsw); 1036 } 1037 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL); 1038