1 /* $NetBSD: xform_esp.c,v 1.46 2015/03/30 03:51:50 ozaki-r Exp $ */ 2 /* $FreeBSD: src/sys/netipsec/xform_esp.c,v 1.2.2.1 2003/01/24 05:11:36 sam Exp $ */ 3 /* $OpenBSD: ip_esp.c,v 1.69 2001/06/26 06:18:59 angelos Exp $ */ 4 5 /* 6 * The authors of this code are John Ioannidis (ji@tla.org), 7 * Angelos D. Keromytis (kermit@csd.uch.gr) and 8 * Niels Provos (provos@physnet.uni-hamburg.de). 9 * 10 * The original version of this code was written by John Ioannidis 11 * for BSD/OS in Athens, Greece, in November 1995. 12 * 13 * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996, 14 * by Angelos D. Keromytis. 15 * 16 * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis 17 * and Niels Provos. 18 * 19 * Additional features in 1999 by Angelos D. Keromytis. 20 * 21 * Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis, 22 * Angelos D. Keromytis and Niels Provos. 23 * Copyright (c) 2001 Angelos D. Keromytis. 24 * 25 * Permission to use, copy, and modify this software with or without fee 26 * is hereby granted, provided that this entire notice is included in 27 * all copies of any software which is or includes a copy or 28 * modification of this software. 29 * You may use this code under the GNU public license if you so wish. Please 30 * contribute changes back to the authors under this freer than GPL license 31 * so that we may further the use of strong encryption without limitations to 32 * all. 33 * 34 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR 35 * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY 36 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE 37 * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR 38 * PURPOSE. 39 */ 40 41 #include <sys/cdefs.h> 42 __KERNEL_RCSID(0, "$NetBSD: xform_esp.c,v 1.46 2015/03/30 03:51:50 ozaki-r Exp $"); 43 44 #include "opt_inet.h" 45 #ifdef __FreeBSD__ 46 #include "opt_inet6.h" 47 #endif 48 #include "opt_ipsec.h" 49 50 #include <sys/param.h> 51 #include <sys/systm.h> 52 #include <sys/mbuf.h> 53 #include <sys/socket.h> 54 #include <sys/syslog.h> 55 #include <sys/kernel.h> 56 /*#include <sys/random.h>*/ 57 #include <sys/sysctl.h> 58 #include <sys/socketvar.h> /* for softnet_lock */ 59 60 #include <net/if.h> 61 62 #include <netinet/in.h> 63 #include <netinet/in_systm.h> 64 #include <netinet/ip.h> 65 #include <netinet/ip_ecn.h> 66 #include <netinet/ip6.h> 67 68 #include <net/route.h> 69 #include <netipsec/ipsec.h> 70 #include <netipsec/ipsec_private.h> 71 #include <netipsec/ah.h> 72 #include <netipsec/ah_var.h> 73 #include <netipsec/esp.h> 74 #include <netipsec/esp_var.h> 75 #include <netipsec/xform.h> 76 77 #ifdef INET6 78 #include <netinet6/ip6_var.h> 79 #include <netipsec/ipsec6.h> 80 # ifdef __FreeBSD__ 81 # include <netinet6/ip6_ecn.h> 82 # endif 83 #endif 84 85 #include <netipsec/key.h> 86 #include <netipsec/key_debug.h> 87 88 #include <netipsec/ipsec_osdep.h> 89 90 #include <opencrypto/cryptodev.h> 91 #include <opencrypto/xform.h> 92 93 percpu_t *espstat_percpu; 94 95 int esp_enable = 1; 96 97 #ifdef __FreeBSD__ 98 SYSCTL_DECL(_net_inet_esp); 99 SYSCTL_INT(_net_inet_esp, OID_AUTO, 100 esp_enable, CTLFLAG_RW, &esp_enable, 0, ""); 101 SYSCTL_STRUCT(_net_inet_esp, IPSECCTL_STATS, 102 stats, CTLFLAG_RD, &espstat, espstat, ""); 103 #endif /* __FreeBSD__ */ 104 105 static int esp_max_ivlen; /* max iv length over all algorithms */ 106 107 static int esp_input_cb(struct cryptop *op); 108 static int esp_output_cb(struct cryptop *crp); 109 110 /* 111 * NB: this is public for use by the PF_KEY support. 112 * NB: if you add support here; be sure to add code to esp_attach below! 113 */ 114 const struct enc_xform * 115 esp_algorithm_lookup(int alg) 116 { 117 if (alg >= ESP_ALG_MAX) 118 return NULL; 119 switch (alg) { 120 case SADB_EALG_DESCBC: 121 return &enc_xform_des; 122 case SADB_EALG_3DESCBC: 123 return &enc_xform_3des; 124 case SADB_X_EALG_AES: 125 return &enc_xform_rijndael128; 126 case SADB_X_EALG_BLOWFISHCBC: 127 return &enc_xform_blf; 128 case SADB_X_EALG_CAST128CBC: 129 return &enc_xform_cast5; 130 case SADB_X_EALG_SKIPJACK: 131 return &enc_xform_skipjack; 132 case SADB_X_EALG_CAMELLIACBC: 133 return &enc_xform_camellia; 134 case SADB_X_EALG_AESCTR: 135 return &enc_xform_aes_ctr; 136 case SADB_X_EALG_AESGCM16: 137 return &enc_xform_aes_gcm; 138 case SADB_X_EALG_AESGMAC: 139 return &enc_xform_aes_gmac; 140 case SADB_EALG_NULL: 141 return &enc_xform_null; 142 } 143 return NULL; 144 } 145 146 size_t 147 esp_hdrsiz(const struct secasvar *sav) 148 { 149 size_t size; 150 151 if (sav != NULL) { 152 /*XXX not right for null algorithm--does it matter??*/ 153 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 154 ("esp_hdrsiz: SA with null xform")); 155 if (sav->flags & SADB_X_EXT_OLD) 156 size = sizeof (struct esp); 157 else 158 size = sizeof (struct newesp); 159 size += sav->tdb_encalgxform->ivsize + 9; 160 /*XXX need alg check???*/ 161 if (sav->tdb_authalgxform != NULL && sav->replay) 162 size += ah_hdrsiz(sav); 163 } else { 164 /* 165 * base header size 166 * + max iv length for CBC mode 167 * + max pad length 168 * + sizeof (pad length field) 169 * + sizeof (next header field) 170 * + max icv supported. 171 */ 172 size = sizeof (struct newesp) + esp_max_ivlen + 9 + 16; 173 } 174 return size; 175 } 176 177 /* 178 * esp_init() is called when an SPI is being set up. 179 */ 180 static int 181 esp_init(struct secasvar *sav, const struct xformsw *xsp) 182 { 183 const struct enc_xform *txform; 184 struct cryptoini cria, crie; 185 int keylen; 186 int error; 187 188 txform = esp_algorithm_lookup(sav->alg_enc); 189 if (txform == NULL) { 190 DPRINTF(("esp_init: unsupported encryption algorithm %d\n", 191 sav->alg_enc)); 192 return EINVAL; 193 } 194 if (sav->key_enc == NULL) { 195 DPRINTF(("esp_init: no encoding key for %s algorithm\n", 196 txform->name)); 197 return EINVAL; 198 } 199 if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) { 200 DPRINTF(("esp_init: 4-byte IV not supported with protocol\n")); 201 return EINVAL; 202 } 203 keylen = _KEYLEN(sav->key_enc); 204 if (txform->minkey > keylen || keylen > txform->maxkey) { 205 DPRINTF(("esp_init: invalid key length %u, must be in " 206 "the range [%u..%u] for algorithm %s\n", 207 keylen, txform->minkey, txform->maxkey, 208 txform->name)); 209 return EINVAL; 210 } 211 212 sav->ivlen = 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 if (sav->alg_enc == SADB_X_EALG_AESGCM16 || 228 sav->alg_enc == SADB_X_EALG_AESGMAC) { 229 switch (keylen) { 230 case 20: 231 sav->alg_auth = SADB_X_AALG_AES128GMAC; 232 sav->tdb_authalgxform = &auth_hash_gmac_aes_128; 233 break; 234 case 28: 235 sav->alg_auth = SADB_X_AALG_AES192GMAC; 236 sav->tdb_authalgxform = &auth_hash_gmac_aes_192; 237 break; 238 case 36: 239 sav->alg_auth = SADB_X_AALG_AES256GMAC; 240 sav->tdb_authalgxform = &auth_hash_gmac_aes_256; 241 break; 242 } 243 memset(&cria, 0, sizeof(cria)); 244 cria.cri_alg = sav->tdb_authalgxform->type; 245 cria.cri_klen = _KEYBITS(sav->key_enc); 246 cria.cri_key = _KEYBUF(sav->key_enc); 247 } 248 249 /* Initialize crypto session. */ 250 memset(&crie, 0, sizeof (crie)); 251 crie.cri_alg = sav->tdb_encalgxform->type; 252 crie.cri_klen = _KEYBITS(sav->key_enc); 253 crie.cri_key = _KEYBUF(sav->key_enc); 254 /* XXX Rounds ? */ 255 256 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 257 /* init both auth & enc */ 258 crie.cri_next = &cria; 259 error = crypto_newsession(&sav->tdb_cryptoid, 260 &crie, crypto_support); 261 } else if (sav->tdb_encalgxform) { 262 error = crypto_newsession(&sav->tdb_cryptoid, 263 &crie, crypto_support); 264 } else if (sav->tdb_authalgxform) { 265 error = crypto_newsession(&sav->tdb_cryptoid, 266 &cria, crypto_support); 267 } else { 268 /* XXX cannot happen? */ 269 DPRINTF(("esp_init: no encoding OR authentication xform!\n")); 270 error = EINVAL; 271 } 272 return error; 273 } 274 275 /* 276 * Paranoia. 277 */ 278 static int 279 esp_zeroize(struct secasvar *sav) 280 { 281 /* NB: ah_zerorize free's the crypto session state */ 282 int error = ah_zeroize(sav); 283 284 if (sav->key_enc) 285 memset(_KEYBUF(sav->key_enc), 0, _KEYLEN(sav->key_enc)); 286 sav->tdb_encalgxform = NULL; 287 sav->tdb_xform = NULL; 288 return error; 289 } 290 291 /* 292 * ESP input processing, called (eventually) through the protocol switch. 293 */ 294 static int 295 esp_input(struct mbuf *m, const struct secasvar *sav, int skip, int protoff) 296 { 297 const struct auth_hash *esph; 298 const struct enc_xform *espx; 299 struct tdb_ident *tdbi; 300 struct tdb_crypto *tc; 301 int plen, alen, hlen, error; 302 struct m_tag *mtag; 303 struct newesp *esp; 304 305 struct cryptodesc *crde; 306 struct cryptop *crp; 307 308 IPSEC_SPLASSERT_SOFTNET("esp_input"); 309 310 IPSEC_ASSERT(sav != NULL, ("esp_input: null SA")); 311 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 312 ("esp_input: null encoding xform")); 313 IPSEC_ASSERT((skip&3) == 0 && (m->m_pkthdr.len&3) == 0, 314 ("esp_input: misaligned packet, skip %u pkt len %u", 315 skip, m->m_pkthdr.len)); 316 317 /* XXX don't pullup, just copy header */ 318 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 319 320 esph = sav->tdb_authalgxform; 321 espx = sav->tdb_encalgxform; 322 323 /* Determine the ESP header length */ 324 if (sav->flags & SADB_X_EXT_OLD) 325 hlen = sizeof (struct esp) + sav->ivlen; 326 else 327 hlen = sizeof (struct newesp) + sav->ivlen; 328 /* Authenticator hash size */ 329 alen = esph ? esph->authsize : 0; 330 331 /* 332 * Verify payload length is multiple of encryption algorithm 333 * block size. 334 * 335 * NB: This works for the null algorithm because the blocksize 336 * is 4 and all packets must be 4-byte aligned regardless 337 * of the algorithm. 338 */ 339 plen = m->m_pkthdr.len - (skip + hlen + alen); 340 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 341 DPRINTF(("esp_input: " 342 "payload of %d octets not a multiple of %d octets," 343 " SA %s/%08lx\n", 344 plen, espx->blocksize, 345 ipsec_address(&sav->sah->saidx.dst), 346 (u_long) ntohl(sav->spi))); 347 ESP_STATINC(ESP_STAT_BADILEN); 348 m_freem(m); 349 return EINVAL; 350 } 351 352 /* 353 * Check sequence number. 354 */ 355 if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) { 356 DPRINTF(("esp_input: packet replay check for %s\n", 357 ipsec_logsastr(sav))); /*XXX*/ 358 ESP_STATINC(ESP_STAT_REPLAY); 359 m_freem(m); 360 return ENOBUFS; /*XXX*/ 361 } 362 363 /* Update the counters */ 364 ESP_STATADD(ESP_STAT_IBYTES, m->m_pkthdr.len - skip - hlen - alen); 365 366 /* Find out if we've already done crypto */ 367 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL); 368 mtag != NULL; 369 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) { 370 tdbi = (struct tdb_ident *) (mtag + 1); 371 if (tdbi->proto == sav->sah->saidx.proto && 372 tdbi->spi == sav->spi && 373 !memcmp(&tdbi->dst, &sav->sah->saidx.dst, 374 sizeof(union sockaddr_union))) 375 break; 376 } 377 378 /* Get crypto descriptors */ 379 crp = crypto_getreq(esph && espx ? 2 : 1); 380 if (crp == NULL) { 381 DPRINTF(("esp_input: failed to acquire crypto descriptors\n")); 382 ESP_STATINC(ESP_STAT_CRYPTO); 383 m_freem(m); 384 return ENOBUFS; 385 } 386 387 /* Get IPsec-specific opaque pointer */ 388 if (esph == NULL || mtag != NULL) 389 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 390 M_XDATA, M_NOWAIT|M_ZERO); 391 else 392 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen, 393 M_XDATA, M_NOWAIT|M_ZERO); 394 if (tc == NULL) { 395 crypto_freereq(crp); 396 DPRINTF(("esp_input: failed to allocate tdb_crypto\n")); 397 ESP_STATINC(ESP_STAT_CRYPTO); 398 m_freem(m); 399 return ENOBUFS; 400 } 401 402 error = m_makewritable(&m, 0, m->m_pkthdr.len, M_NOWAIT); 403 if (error) { 404 m_freem(m); 405 free(tc, M_XDATA); 406 crypto_freereq(crp); 407 DPRINTF(("esp_input: m_makewritable failed\n")); 408 ESP_STATINC(ESP_STAT_CRYPTO); 409 return error; 410 } 411 412 tc->tc_ptr = mtag; 413 414 if (esph) { 415 struct cryptodesc *crda = crp->crp_desc; 416 417 IPSEC_ASSERT(crda != NULL, ("esp_input: null ah crypto descriptor")); 418 419 /* Authentication descriptor */ 420 crda->crd_skip = skip; 421 if (espx && espx->type == CRYPTO_AES_GCM_16) 422 crda->crd_len = hlen - sav->ivlen; 423 else 424 crda->crd_len = m->m_pkthdr.len - (skip + alen); 425 crda->crd_inject = m->m_pkthdr.len - alen; 426 427 crda->crd_alg = esph->type; 428 if (espx && (espx->type == CRYPTO_AES_GCM_16 || 429 espx->type == CRYPTO_AES_GMAC)) { 430 crda->crd_key = _KEYBUF(sav->key_enc); 431 crda->crd_klen = _KEYBITS(sav->key_enc); 432 } else { 433 crda->crd_key = _KEYBUF(sav->key_auth); 434 crda->crd_klen = _KEYBITS(sav->key_auth); 435 } 436 437 /* Copy the authenticator */ 438 if (mtag == NULL) 439 m_copydata(m, m->m_pkthdr.len - alen, alen, 440 (tc + 1)); 441 442 /* Chain authentication request */ 443 crde = crda->crd_next; 444 } else { 445 crde = crp->crp_desc; 446 } 447 448 /* Crypto operation descriptor */ 449 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 450 crp->crp_flags = CRYPTO_F_IMBUF; 451 crp->crp_buf = m; 452 crp->crp_callback = esp_input_cb; 453 crp->crp_sid = sav->tdb_cryptoid; 454 crp->crp_opaque = tc; 455 456 /* These are passed as-is to the callback */ 457 tc->tc_spi = sav->spi; 458 tc->tc_dst = sav->sah->saidx.dst; 459 tc->tc_proto = sav->sah->saidx.proto; 460 tc->tc_protoff = protoff; 461 tc->tc_skip = skip; 462 463 /* Decryption descriptor */ 464 if (espx) { 465 IPSEC_ASSERT(crde != NULL, ("esp_input: null esp crypto descriptor")); 466 crde->crd_skip = skip + hlen; 467 if (espx->type == CRYPTO_AES_GMAC) 468 crde->crd_len = 0; 469 else 470 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 471 crde->crd_inject = skip + hlen - sav->ivlen; 472 473 crde->crd_alg = espx->type; 474 crde->crd_key = _KEYBUF(sav->key_enc); 475 crde->crd_klen = _KEYBITS(sav->key_enc); 476 /* XXX Rounds ? */ 477 } 478 479 if (mtag == NULL) 480 return crypto_dispatch(crp); 481 else 482 return esp_input_cb(crp); 483 } 484 485 #ifdef INET6 486 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \ 487 if (saidx->dst.sa.sa_family == AF_INET6) { \ 488 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \ 489 } else { \ 490 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \ 491 } \ 492 } while (0) 493 #else 494 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \ 495 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag)) 496 #endif 497 498 /* 499 * ESP input callback from the crypto driver. 500 */ 501 static int 502 esp_input_cb(struct cryptop *crp) 503 { 504 u_int8_t lastthree[3], aalg[AH_ALEN_MAX]; 505 int s, hlen, skip, protoff, error; 506 struct mbuf *m; 507 struct cryptodesc *crd __diagused; 508 const struct auth_hash *esph; 509 struct tdb_crypto *tc; 510 struct m_tag *mtag; 511 struct secasvar *sav; 512 struct secasindex *saidx; 513 void *ptr; 514 u_int16_t dport; 515 u_int16_t sport; 516 517 crd = crp->crp_desc; 518 IPSEC_ASSERT(crd != NULL, ("esp_input_cb: null crypto descriptor!")); 519 520 tc = (struct tdb_crypto *) crp->crp_opaque; 521 IPSEC_ASSERT(tc != NULL, ("esp_input_cb: null opaque crypto data area!")); 522 skip = tc->tc_skip; 523 protoff = tc->tc_protoff; 524 mtag = (struct m_tag *) tc->tc_ptr; 525 m = (struct mbuf *) crp->crp_buf; 526 527 /* find the source port for NAT-T */ 528 nat_t_ports_get(m, &dport, &sport); 529 530 s = splsoftnet(); 531 mutex_enter(softnet_lock); 532 533 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi, sport, dport); 534 if (sav == NULL) { 535 ESP_STATINC(ESP_STAT_NOTDB); 536 DPRINTF(("esp_input_cb: SA expired while in crypto " 537 "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst), 538 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 539 error = ENOBUFS; /*XXX*/ 540 goto bad; 541 } 542 543 saidx = &sav->sah->saidx; 544 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 545 saidx->dst.sa.sa_family == AF_INET6, 546 ("esp_input_cb: unexpected protocol family %u", 547 saidx->dst.sa.sa_family)); 548 549 esph = sav->tdb_authalgxform; 550 551 /* Check for crypto errors */ 552 if (crp->crp_etype) { 553 /* Reset the session ID */ 554 if (sav->tdb_cryptoid != 0) 555 sav->tdb_cryptoid = crp->crp_sid; 556 557 if (crp->crp_etype == EAGAIN) { 558 KEY_FREESAV(&sav); 559 mutex_exit(softnet_lock); 560 splx(s); 561 return crypto_dispatch(crp); 562 } 563 564 ESP_STATINC(ESP_STAT_NOXFORM); 565 DPRINTF(("esp_input_cb: crypto error %d\n", crp->crp_etype)); 566 error = crp->crp_etype; 567 goto bad; 568 } 569 570 /* Shouldn't happen... */ 571 if (m == NULL) { 572 ESP_STATINC(ESP_STAT_CRYPTO); 573 DPRINTF(("esp_input_cb: bogus returned buffer from crypto\n")); 574 error = EINVAL; 575 goto bad; 576 } 577 ESP_STATINC(ESP_STAT_HIST + sav->alg_enc); 578 579 /* If authentication was performed, check now. */ 580 if (esph != NULL) { 581 /* 582 * If we have a tag, it means an IPsec-aware NIC did 583 * the verification for us. Otherwise we need to 584 * check the authentication calculation. 585 */ 586 AH_STATINC(AH_STAT_HIST + sav->alg_auth); 587 if (mtag == NULL) { 588 /* Copy the authenticator from the packet */ 589 m_copydata(m, m->m_pkthdr.len - esph->authsize, 590 esph->authsize, aalg); 591 592 ptr = (tc + 1); 593 594 /* Verify authenticator */ 595 if (!consttime_memequal(ptr, aalg, esph->authsize)) { 596 DPRINTF(("esp_input_cb: " 597 "authentication hash mismatch for packet in SA %s/%08lx\n", 598 ipsec_address(&saidx->dst), 599 (u_long) ntohl(sav->spi))); 600 ESP_STATINC(ESP_STAT_BADAUTH); 601 error = EACCES; 602 goto bad; 603 } 604 } 605 606 /* Remove trailing authenticator */ 607 m_adj(m, -(esph->authsize)); 608 } 609 610 /* Release the crypto descriptors */ 611 free(tc, M_XDATA), tc = NULL; 612 crypto_freereq(crp), crp = NULL; 613 614 /* 615 * Packet is now decrypted. 616 */ 617 m->m_flags |= M_DECRYPTED; 618 619 /* 620 * Update replay sequence number, if appropriate. 621 */ 622 if (sav->replay) { 623 u_int32_t seq; 624 625 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 626 sizeof (seq), &seq); 627 if (ipsec_updatereplay(ntohl(seq), sav)) { 628 DPRINTF(("%s: packet replay check for %s\n", __func__, 629 ipsec_logsastr(sav))); 630 ESP_STATINC(ESP_STAT_REPLAY); 631 error = ENOBUFS; 632 goto bad; 633 } 634 } 635 636 /* Determine the ESP header length */ 637 if (sav->flags & SADB_X_EXT_OLD) 638 hlen = sizeof (struct esp) + sav->ivlen; 639 else 640 hlen = sizeof (struct newesp) + sav->ivlen; 641 642 /* Remove the ESP header and IV from the mbuf. */ 643 error = m_striphdr(m, skip, hlen); 644 if (error) { 645 ESP_STATINC(ESP_STAT_HDROPS); 646 DPRINTF(("esp_input_cb: bad mbuf chain, SA %s/%08lx\n", 647 ipsec_address(&sav->sah->saidx.dst), 648 (u_long) ntohl(sav->spi))); 649 goto bad; 650 } 651 652 /* Save the last three bytes of decrypted data */ 653 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 654 655 /* Verify pad length */ 656 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 657 ESP_STATINC(ESP_STAT_BADILEN); 658 DPRINTF(("esp_input_cb: invalid padding length %d " 659 "for %u byte packet in SA %s/%08lx\n", 660 lastthree[1], m->m_pkthdr.len - skip, 661 ipsec_address(&sav->sah->saidx.dst), 662 (u_long) ntohl(sav->spi))); 663 error = EINVAL; 664 goto bad; 665 } 666 667 /* Verify correct decryption by checking the last padding bytes */ 668 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 669 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 670 ESP_STATINC(ESP_STAT_BADENC); 671 DPRINTF(("esp_input_cb: decryption failed " 672 "for packet in SA %s/%08lx\n", 673 ipsec_address(&sav->sah->saidx.dst), 674 (u_long) ntohl(sav->spi))); 675 DPRINTF(("esp_input_cb: %x %x\n", lastthree[0], lastthree[1])); 676 error = EINVAL; 677 goto bad; 678 } 679 } 680 681 /* Trim the mbuf chain to remove trailing authenticator and padding */ 682 m_adj(m, -(lastthree[1] + 2)); 683 684 /* Restore the Next Protocol field */ 685 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 686 687 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag); 688 689 KEY_FREESAV(&sav); 690 mutex_exit(softnet_lock); 691 splx(s); 692 return error; 693 bad: 694 if (sav) 695 KEY_FREESAV(&sav); 696 mutex_exit(softnet_lock); 697 splx(s); 698 if (m != NULL) 699 m_freem(m); 700 if (tc != NULL) 701 free(tc, M_XDATA); 702 if (crp != NULL) 703 crypto_freereq(crp); 704 return error; 705 } 706 707 /* 708 * ESP output routine, called by ipsec[46]_process_packet(). 709 */ 710 static int 711 esp_output( 712 struct mbuf *m, 713 struct ipsecrequest *isr, 714 struct mbuf **mp, 715 int skip, 716 int protoff 717 ) 718 { 719 const struct enc_xform *espx; 720 const struct auth_hash *esph; 721 int hlen, rlen, padding, blks, alen, i, roff; 722 struct mbuf *mo = NULL; 723 struct tdb_crypto *tc; 724 const struct secasvar *sav; 725 struct secasindex *saidx; 726 unsigned char *pad; 727 u_int8_t prot; 728 int error, maxpacketsize; 729 730 struct cryptodesc *crde = NULL, *crda = NULL; 731 struct cryptop *crp; 732 733 IPSEC_SPLASSERT_SOFTNET("esp_output"); 734 735 sav = isr->sav; 736 IPSEC_ASSERT(sav != NULL, ("esp_output: null SA")); 737 esph = sav->tdb_authalgxform; 738 espx = sav->tdb_encalgxform; 739 IPSEC_ASSERT(espx != NULL, ("esp_output: null encoding xform")); 740 741 if (sav->flags & SADB_X_EXT_OLD) 742 hlen = sizeof (struct esp) + sav->ivlen; 743 else 744 hlen = sizeof (struct newesp) + sav->ivlen; 745 746 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 747 /* 748 * NB: The null encoding transform has a blocksize of 4 749 * so that headers are properly aligned. 750 */ 751 blks = espx->blocksize; /* IV blocksize */ 752 753 /* XXX clamp padding length a la KAME??? */ 754 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 755 756 if (esph) 757 alen = esph->authsize; 758 else 759 alen = 0; 760 761 ESP_STATINC(ESP_STAT_OUTPUT); 762 763 saidx = &sav->sah->saidx; 764 /* Check for maximum packet size violations. */ 765 switch (saidx->dst.sa.sa_family) { 766 #ifdef INET 767 case AF_INET: 768 maxpacketsize = IP_MAXPACKET; 769 break; 770 #endif /* INET */ 771 #ifdef INET6 772 case AF_INET6: 773 maxpacketsize = IPV6_MAXPACKET; 774 break; 775 #endif /* INET6 */ 776 default: 777 DPRINTF(("esp_output: unknown/unsupported protocol " 778 "family %d, SA %s/%08lx\n", 779 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst), 780 (u_long) ntohl(sav->spi))); 781 ESP_STATINC(ESP_STAT_NOPF); 782 error = EPFNOSUPPORT; 783 goto bad; 784 } 785 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 786 DPRINTF(("esp_output: packet in SA %s/%08lx got too big " 787 "(len %u, max len %u)\n", 788 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi), 789 skip + hlen + rlen + padding + alen, maxpacketsize)); 790 ESP_STATINC(ESP_STAT_TOOBIG); 791 error = EMSGSIZE; 792 goto bad; 793 } 794 795 /* Update the counters. */ 796 ESP_STATADD(ESP_STAT_OBYTES, m->m_pkthdr.len - skip); 797 798 m = m_clone(m); 799 if (m == NULL) { 800 DPRINTF(("esp_output: cannot clone mbuf chain, SA %s/%08lx\n", 801 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 802 ESP_STATINC(ESP_STAT_HDROPS); 803 error = ENOBUFS; 804 goto bad; 805 } 806 807 /* Inject ESP header. */ 808 mo = m_makespace(m, skip, hlen, &roff); 809 if (mo == NULL) { 810 DPRINTF(("esp_output: failed to inject %u byte ESP hdr for SA " 811 "%s/%08lx\n", 812 hlen, ipsec_address(&saidx->dst), 813 (u_long) ntohl(sav->spi))); 814 ESP_STATINC(ESP_STAT_HDROPS); /* XXX diffs from openbsd */ 815 error = ENOBUFS; 816 goto bad; 817 } 818 819 /* Initialize ESP header. */ 820 memcpy(mtod(mo, char *) + roff, &sav->spi, sizeof(u_int32_t)); 821 if (sav->replay) { 822 u_int32_t replay; 823 824 #ifdef IPSEC_DEBUG 825 /* Emulate replay attack when ipsec_replay is TRUE. */ 826 if (!ipsec_replay) 827 #endif 828 sav->replay->count++; 829 830 replay = htonl(sav->replay->count); 831 bcopy(&replay, 832 mtod(mo,char *) + roff + sizeof(u_int32_t), 833 sizeof(u_int32_t)); 834 } 835 836 /* 837 * Add padding -- better to do it ourselves than use the crypto engine, 838 * although if/when we support compression, we'd have to do that. 839 */ 840 pad = (u_char *) m_pad(m, padding + alen); 841 if (pad == NULL) { 842 DPRINTF(("esp_output: m_pad failed for SA %s/%08lx\n", 843 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 844 m = NULL; /* NB: free'd by m_pad */ 845 error = ENOBUFS; 846 goto bad; 847 } 848 849 /* 850 * Add padding: random, zero, or self-describing. 851 * XXX catch unexpected setting 852 */ 853 switch (sav->flags & SADB_X_EXT_PMASK) { 854 case SADB_X_EXT_PRAND: 855 (void) read_random(pad, padding - 2); 856 break; 857 case SADB_X_EXT_PZERO: 858 memset(pad, 0, padding - 2); 859 break; 860 case SADB_X_EXT_PSEQ: 861 for (i = 0; i < padding - 2; i++) 862 pad[i] = i+1; 863 break; 864 } 865 866 /* Fix padding length and Next Protocol in padding itself. */ 867 pad[padding - 2] = padding - 2; 868 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 869 870 /* Fix Next Protocol in IPv4/IPv6 header. */ 871 prot = IPPROTO_ESP; 872 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 873 874 /* Get crypto descriptors. */ 875 crp = crypto_getreq(esph && espx ? 2 : 1); 876 if (crp == NULL) { 877 DPRINTF(("esp_output: failed to acquire crypto descriptors\n")); 878 ESP_STATINC(ESP_STAT_CRYPTO); 879 error = ENOBUFS; 880 goto bad; 881 } 882 883 if (espx) { 884 crde = crp->crp_desc; 885 crda = crde->crd_next; 886 887 /* Encryption descriptor. */ 888 crde->crd_skip = skip + hlen; 889 if (espx->type == CRYPTO_AES_GMAC) 890 crde->crd_len = 0; 891 else 892 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 893 crde->crd_flags = CRD_F_ENCRYPT; 894 crde->crd_inject = skip + hlen - sav->ivlen; 895 896 /* Encryption operation. */ 897 crde->crd_alg = espx->type; 898 crde->crd_key = _KEYBUF(sav->key_enc); 899 crde->crd_klen = _KEYBITS(sav->key_enc); 900 /* XXX Rounds ? */ 901 } else 902 crda = crp->crp_desc; 903 904 /* IPsec-specific opaque crypto info. */ 905 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 906 M_XDATA, M_NOWAIT|M_ZERO); 907 if (tc == NULL) { 908 crypto_freereq(crp); 909 DPRINTF(("esp_output: failed to allocate tdb_crypto\n")); 910 ESP_STATINC(ESP_STAT_CRYPTO); 911 error = ENOBUFS; 912 goto bad; 913 } 914 915 /* Callback parameters */ 916 tc->tc_isr = isr; 917 tc->tc_spi = sav->spi; 918 tc->tc_dst = saidx->dst; 919 tc->tc_proto = saidx->proto; 920 921 /* Crypto operation descriptor. */ 922 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 923 crp->crp_flags = CRYPTO_F_IMBUF; 924 crp->crp_buf = m; 925 crp->crp_callback = esp_output_cb; 926 crp->crp_opaque = tc; 927 crp->crp_sid = sav->tdb_cryptoid; 928 929 if (esph) { 930 /* Authentication descriptor. */ 931 crda->crd_skip = skip; 932 if (espx && espx->type == CRYPTO_AES_GCM_16) 933 crda->crd_len = hlen - sav->ivlen; 934 else 935 crda->crd_len = m->m_pkthdr.len - (skip + alen); 936 crda->crd_inject = m->m_pkthdr.len - alen; 937 938 /* Authentication operation. */ 939 crda->crd_alg = esph->type; 940 if (espx && (espx->type == CRYPTO_AES_GCM_16 || 941 espx->type == CRYPTO_AES_GMAC)) { 942 crda->crd_key = _KEYBUF(sav->key_enc); 943 crda->crd_klen = _KEYBITS(sav->key_enc); 944 } else { 945 crda->crd_key = _KEYBUF(sav->key_auth); 946 crda->crd_klen = _KEYBITS(sav->key_auth); 947 } 948 } 949 950 return crypto_dispatch(crp); 951 bad: 952 if (m) 953 m_freem(m); 954 return (error); 955 } 956 957 /* 958 * ESP output callback from the crypto driver. 959 */ 960 static int 961 esp_output_cb(struct cryptop *crp) 962 { 963 struct tdb_crypto *tc; 964 struct ipsecrequest *isr; 965 struct secasvar *sav; 966 struct mbuf *m; 967 int s, err, error; 968 969 tc = (struct tdb_crypto *) crp->crp_opaque; 970 IPSEC_ASSERT(tc != NULL, ("esp_output_cb: null opaque data area!")); 971 m = (struct mbuf *) crp->crp_buf; 972 973 s = splsoftnet(); 974 mutex_enter(softnet_lock); 975 976 isr = tc->tc_isr; 977 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi, 0, 0); 978 if (sav == NULL) { 979 ESP_STATINC(ESP_STAT_NOTDB); 980 DPRINTF(("esp_output_cb: SA expired while in crypto " 981 "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst), 982 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 983 error = ENOBUFS; /*XXX*/ 984 goto bad; 985 } 986 IPSEC_ASSERT(isr->sav == sav, 987 ("esp_output_cb: SA changed was %p now %p\n", isr->sav, sav)); 988 989 /* Check for crypto errors. */ 990 if (crp->crp_etype) { 991 /* Reset session ID. */ 992 if (sav->tdb_cryptoid != 0) 993 sav->tdb_cryptoid = crp->crp_sid; 994 995 if (crp->crp_etype == EAGAIN) { 996 KEY_FREESAV(&sav); 997 mutex_exit(softnet_lock); 998 splx(s); 999 return crypto_dispatch(crp); 1000 } 1001 1002 ESP_STATINC(ESP_STAT_NOXFORM); 1003 DPRINTF(("esp_output_cb: crypto error %d\n", crp->crp_etype)); 1004 error = crp->crp_etype; 1005 goto bad; 1006 } 1007 1008 /* Shouldn't happen... */ 1009 if (m == NULL) { 1010 ESP_STATINC(ESP_STAT_CRYPTO); 1011 DPRINTF(("esp_output_cb: bogus returned buffer from crypto\n")); 1012 error = EINVAL; 1013 goto bad; 1014 } 1015 ESP_STATINC(ESP_STAT_HIST + sav->alg_enc); 1016 if (sav->tdb_authalgxform != NULL) 1017 AH_STATINC(AH_STAT_HIST + sav->alg_auth); 1018 1019 /* Release crypto descriptors. */ 1020 free(tc, M_XDATA); 1021 crypto_freereq(crp); 1022 1023 #ifdef IPSEC_DEBUG 1024 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 1025 if (ipsec_integrity) { 1026 static unsigned char ipseczeroes[AH_ALEN_MAX]; 1027 const struct auth_hash *esph; 1028 1029 /* 1030 * Corrupt HMAC if we want to test integrity verification of 1031 * the other side. 1032 */ 1033 esph = sav->tdb_authalgxform; 1034 if (esph != NULL) { 1035 m_copyback(m, m->m_pkthdr.len - esph->authsize, 1036 esph->authsize, ipseczeroes); 1037 } 1038 } 1039 #endif 1040 1041 /* NB: m is reclaimed by ipsec_process_done. */ 1042 err = ipsec_process_done(m, isr); 1043 KEY_FREESAV(&sav); 1044 mutex_exit(softnet_lock); 1045 splx(s); 1046 return err; 1047 bad: 1048 if (sav) 1049 KEY_FREESAV(&sav); 1050 mutex_exit(softnet_lock); 1051 splx(s); 1052 if (m) 1053 m_freem(m); 1054 free(tc, M_XDATA); 1055 crypto_freereq(crp); 1056 return error; 1057 } 1058 1059 static struct xformsw esp_xformsw = { 1060 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 1061 esp_init, esp_zeroize, esp_input, 1062 esp_output, 1063 NULL, 1064 }; 1065 1066 INITFN void 1067 esp_attach(void) 1068 { 1069 1070 espstat_percpu = percpu_alloc(sizeof(uint64_t) * ESP_NSTATS); 1071 1072 #define MAXIV(xform) \ 1073 if (xform.ivsize > esp_max_ivlen) \ 1074 esp_max_ivlen = xform.ivsize \ 1075 1076 esp_max_ivlen = 0; 1077 MAXIV(enc_xform_des); /* SADB_EALG_DESCBC */ 1078 MAXIV(enc_xform_3des); /* SADB_EALG_3DESCBC */ 1079 MAXIV(enc_xform_rijndael128); /* SADB_X_EALG_AES */ 1080 MAXIV(enc_xform_blf); /* SADB_X_EALG_BLOWFISHCBC */ 1081 MAXIV(enc_xform_cast5); /* SADB_X_EALG_CAST128CBC */ 1082 MAXIV(enc_xform_skipjack); /* SADB_X_EALG_SKIPJACK */ 1083 MAXIV(enc_xform_camellia); /* SADB_X_EALG_CAMELLIACBC */ 1084 MAXIV(enc_xform_aes_ctr); /* SADB_X_EALG_AESCTR */ 1085 MAXIV(enc_xform_null); /* SADB_EALG_NULL */ 1086 1087 xform_register(&esp_xformsw); 1088 #undef MAXIV 1089 } 1090 #ifdef __FreeBSD__ 1091 SYSINIT(esp_xform_init, SI_SUB_DRIVERS, SI_ORDER_FIRST, esp_attach, NULL) 1092 #else 1093 #endif 1094