1 /* $NetBSD: xform_esp.c,v 1.43 2013/06/24 04:21:20 riastradh 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 1.43 2013/06/24 04:21:20 riastradh Exp $"); 43 44 #include "opt_inet.h" 45 #ifdef __FreeBSD__ 46 #include "opt_inet6.h" 47 #endif 48 49 #include <sys/param.h> 50 #include <sys/systm.h> 51 #include <sys/mbuf.h> 52 #include <sys/socket.h> 53 #include <sys/syslog.h> 54 #include <sys/kernel.h> 55 /*#include <sys/random.h>*/ 56 #include <sys/sysctl.h> 57 #include <sys/socketvar.h> /* for softnet_lock */ 58 59 #include <net/if.h> 60 61 #include <netinet/in.h> 62 #include <netinet/in_systm.h> 63 #include <netinet/ip.h> 64 #include <netinet/ip_ecn.h> 65 #include <netinet/ip6.h> 66 67 #include <net/route.h> 68 #include <netipsec/ipsec.h> 69 #include <netipsec/ipsec_private.h> 70 #include <netipsec/ah.h> 71 #include <netipsec/ah_var.h> 72 #include <netipsec/esp.h> 73 #include <netipsec/esp_var.h> 74 #include <netipsec/xform.h> 75 76 #ifdef INET6 77 #include <netinet6/ip6_var.h> 78 #include <netipsec/ipsec6.h> 79 # ifdef __FreeBSD__ 80 # include <netinet6/ip6_ecn.h> 81 # endif 82 #endif 83 84 #include <netipsec/key.h> 85 #include <netipsec/key_debug.h> 86 87 #include <netipsec/ipsec_osdep.h> 88 89 #include <opencrypto/cryptodev.h> 90 #include <opencrypto/xform.h> 91 92 percpu_t *espstat_percpu; 93 94 int esp_enable = 1; 95 96 #ifdef __FreeBSD__ 97 SYSCTL_DECL(_net_inet_esp); 98 SYSCTL_INT(_net_inet_esp, OID_AUTO, 99 esp_enable, CTLFLAG_RW, &esp_enable, 0, ""); 100 SYSCTL_STRUCT(_net_inet_esp, IPSECCTL_STATS, 101 stats, CTLFLAG_RD, &espstat, espstat, ""); 102 #endif /* __FreeBSD__ */ 103 104 static int esp_max_ivlen; /* max iv length over all algorithms */ 105 106 static int esp_input_cb(struct cryptop *op); 107 static int esp_output_cb(struct cryptop *crp); 108 109 /* 110 * NB: this is public for use by the PF_KEY support. 111 * NB: if you add support here; be sure to add code to esp_attach below! 112 */ 113 const struct enc_xform * 114 esp_algorithm_lookup(int alg) 115 { 116 if (alg >= ESP_ALG_MAX) 117 return NULL; 118 switch (alg) { 119 case SADB_EALG_DESCBC: 120 return &enc_xform_des; 121 case SADB_EALG_3DESCBC: 122 return &enc_xform_3des; 123 case SADB_X_EALG_AES: 124 return &enc_xform_rijndael128; 125 case SADB_X_EALG_BLOWFISHCBC: 126 return &enc_xform_blf; 127 case SADB_X_EALG_CAST128CBC: 128 return &enc_xform_cast5; 129 case SADB_X_EALG_SKIPJACK: 130 return &enc_xform_skipjack; 131 case SADB_X_EALG_CAMELLIACBC: 132 return &enc_xform_camellia; 133 case SADB_X_EALG_AESCTR: 134 return &enc_xform_aes_ctr; 135 case SADB_X_EALG_AESGCM16: 136 return &enc_xform_aes_gcm; 137 case SADB_X_EALG_AESGMAC: 138 return &enc_xform_aes_gmac; 139 case SADB_EALG_NULL: 140 return &enc_xform_null; 141 } 142 return NULL; 143 } 144 145 size_t 146 esp_hdrsiz(const struct secasvar *sav) 147 { 148 size_t size; 149 150 if (sav != NULL) { 151 /*XXX not right for null algorithm--does it matter??*/ 152 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 153 ("esp_hdrsiz: SA with null xform")); 154 if (sav->flags & SADB_X_EXT_OLD) 155 size = sizeof (struct esp); 156 else 157 size = sizeof (struct newesp); 158 size += sav->tdb_encalgxform->ivsize + 9; 159 /*XXX need alg check???*/ 160 if (sav->tdb_authalgxform != NULL && sav->replay) 161 size += ah_hdrsiz(sav); 162 } else { 163 /* 164 * base header size 165 * + max iv length for CBC mode 166 * + max pad length 167 * + sizeof (pad length field) 168 * + sizeof (next header field) 169 * + max icv supported. 170 */ 171 size = sizeof (struct newesp) + esp_max_ivlen + 9 + 16; 172 } 173 return size; 174 } 175 176 /* 177 * esp_init() is called when an SPI is being set up. 178 */ 179 static int 180 esp_init(struct secasvar *sav, const struct xformsw *xsp) 181 { 182 const struct enc_xform *txform; 183 struct cryptoini cria, crie; 184 int keylen; 185 int error; 186 187 txform = esp_algorithm_lookup(sav->alg_enc); 188 if (txform == NULL) { 189 DPRINTF(("esp_init: unsupported encryption algorithm %d\n", 190 sav->alg_enc)); 191 return EINVAL; 192 } 193 if (sav->key_enc == NULL) { 194 DPRINTF(("esp_init: no encoding key for %s algorithm\n", 195 txform->name)); 196 return EINVAL; 197 } 198 if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) { 199 DPRINTF(("esp_init: 4-byte IV not supported with protocol\n")); 200 return EINVAL; 201 } 202 keylen = _KEYLEN(sav->key_enc); 203 if (txform->minkey > keylen || keylen > txform->maxkey) { 204 DPRINTF(("esp_init: invalid key length %u, must be in " 205 "the range [%u..%u] for algorithm %s\n", 206 keylen, txform->minkey, txform->maxkey, 207 txform->name)); 208 return EINVAL; 209 } 210 211 sav->ivlen = txform->ivsize; 212 213 /* 214 * Setup AH-related state. 215 */ 216 if (sav->alg_auth != 0) { 217 error = ah_init0(sav, xsp, &cria); 218 if (error) 219 return error; 220 } 221 222 /* NB: override anything set in ah_init0 */ 223 sav->tdb_xform = xsp; 224 sav->tdb_encalgxform = txform; 225 226 if (sav->alg_enc == SADB_X_EALG_AESGCM16 || 227 sav->alg_enc == SADB_X_EALG_AESGMAC) { 228 switch (keylen) { 229 case 20: 230 sav->alg_auth = SADB_X_AALG_AES128GMAC; 231 sav->tdb_authalgxform = &auth_hash_gmac_aes_128; 232 break; 233 case 28: 234 sav->alg_auth = SADB_X_AALG_AES192GMAC; 235 sav->tdb_authalgxform = &auth_hash_gmac_aes_192; 236 break; 237 case 36: 238 sav->alg_auth = SADB_X_AALG_AES256GMAC; 239 sav->tdb_authalgxform = &auth_hash_gmac_aes_256; 240 break; 241 } 242 memset(&cria, 0, sizeof(cria)); 243 cria.cri_alg = sav->tdb_authalgxform->type; 244 cria.cri_klen = _KEYBITS(sav->key_enc); 245 cria.cri_key = _KEYBUF(sav->key_enc); 246 } 247 248 /* Initialize crypto session. */ 249 memset(&crie, 0, sizeof (crie)); 250 crie.cri_alg = sav->tdb_encalgxform->type; 251 crie.cri_klen = _KEYBITS(sav->key_enc); 252 crie.cri_key = _KEYBUF(sav->key_enc); 253 /* XXX Rounds ? */ 254 255 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 256 /* init both auth & enc */ 257 crie.cri_next = &cria; 258 error = crypto_newsession(&sav->tdb_cryptoid, 259 &crie, crypto_support); 260 } else if (sav->tdb_encalgxform) { 261 error = crypto_newsession(&sav->tdb_cryptoid, 262 &crie, crypto_support); 263 } else if (sav->tdb_authalgxform) { 264 error = crypto_newsession(&sav->tdb_cryptoid, 265 &cria, crypto_support); 266 } else { 267 /* XXX cannot happen? */ 268 DPRINTF(("esp_init: no encoding OR authentication xform!\n")); 269 error = EINVAL; 270 } 271 return error; 272 } 273 274 /* 275 * Paranoia. 276 */ 277 static int 278 esp_zeroize(struct secasvar *sav) 279 { 280 /* NB: ah_zerorize free's the crypto session state */ 281 int error = ah_zeroize(sav); 282 283 if (sav->key_enc) 284 memset(_KEYBUF(sav->key_enc), 0, _KEYLEN(sav->key_enc)); 285 sav->tdb_encalgxform = NULL; 286 sav->tdb_xform = NULL; 287 return error; 288 } 289 290 /* 291 * ESP input processing, called (eventually) through the protocol switch. 292 */ 293 static int 294 esp_input(struct mbuf *m, const struct secasvar *sav, int skip, int protoff) 295 { 296 const struct auth_hash *esph; 297 const struct enc_xform *espx; 298 struct tdb_ident *tdbi; 299 struct tdb_crypto *tc; 300 int plen, alen, hlen, error; 301 struct m_tag *mtag; 302 struct newesp *esp; 303 304 struct cryptodesc *crde; 305 struct cryptop *crp; 306 307 IPSEC_SPLASSERT_SOFTNET("esp_input"); 308 309 IPSEC_ASSERT(sav != NULL, ("esp_input: null SA")); 310 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 311 ("esp_input: null encoding xform")); 312 IPSEC_ASSERT((skip&3) == 0 && (m->m_pkthdr.len&3) == 0, 313 ("esp_input: misaligned packet, skip %u pkt len %u", 314 skip, m->m_pkthdr.len)); 315 316 /* XXX don't pullup, just copy header */ 317 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 318 319 esph = sav->tdb_authalgxform; 320 espx = sav->tdb_encalgxform; 321 322 /* Determine the ESP header length */ 323 if (sav->flags & SADB_X_EXT_OLD) 324 hlen = sizeof (struct esp) + sav->ivlen; 325 else 326 hlen = sizeof (struct newesp) + sav->ivlen; 327 /* Authenticator hash size */ 328 alen = esph ? esph->authsize : 0; 329 330 /* 331 * Verify payload length is multiple of encryption algorithm 332 * block size. 333 * 334 * NB: This works for the null algorithm because the blocksize 335 * is 4 and all packets must be 4-byte aligned regardless 336 * of the algorithm. 337 */ 338 plen = m->m_pkthdr.len - (skip + hlen + alen); 339 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 340 DPRINTF(("esp_input: " 341 "payload of %d octets not a multiple of %d octets," 342 " SA %s/%08lx\n", 343 plen, espx->blocksize, 344 ipsec_address(&sav->sah->saidx.dst), 345 (u_long) ntohl(sav->spi))); 346 ESP_STATINC(ESP_STAT_BADILEN); 347 m_freem(m); 348 return EINVAL; 349 } 350 351 /* 352 * Check sequence number. 353 */ 354 if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) { 355 DPRINTF(("esp_input: packet replay check for %s\n", 356 ipsec_logsastr(sav))); /*XXX*/ 357 ESP_STATINC(ESP_STAT_REPLAY); 358 m_freem(m); 359 return ENOBUFS; /*XXX*/ 360 } 361 362 /* Update the counters */ 363 ESP_STATADD(ESP_STAT_IBYTES, m->m_pkthdr.len - skip - hlen - alen); 364 365 /* Find out if we've already done crypto */ 366 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL); 367 mtag != NULL; 368 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) { 369 tdbi = (struct tdb_ident *) (mtag + 1); 370 if (tdbi->proto == sav->sah->saidx.proto && 371 tdbi->spi == sav->spi && 372 !memcmp(&tdbi->dst, &sav->sah->saidx.dst, 373 sizeof(union sockaddr_union))) 374 break; 375 } 376 377 /* Get crypto descriptors */ 378 crp = crypto_getreq(esph && espx ? 2 : 1); 379 if (crp == NULL) { 380 DPRINTF(("esp_input: failed to acquire crypto descriptors\n")); 381 ESP_STATINC(ESP_STAT_CRYPTO); 382 m_freem(m); 383 return ENOBUFS; 384 } 385 386 /* Get IPsec-specific opaque pointer */ 387 if (esph == NULL || mtag != NULL) 388 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 389 M_XDATA, M_NOWAIT|M_ZERO); 390 else 391 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen, 392 M_XDATA, M_NOWAIT|M_ZERO); 393 if (tc == NULL) { 394 crypto_freereq(crp); 395 DPRINTF(("esp_input: failed to allocate tdb_crypto\n")); 396 ESP_STATINC(ESP_STAT_CRYPTO); 397 m_freem(m); 398 return ENOBUFS; 399 } 400 401 error = m_makewritable(&m, 0, m->m_pkthdr.len, M_NOWAIT); 402 if (error) { 403 m_freem(m); 404 free(tc, M_XDATA); 405 crypto_freereq(crp); 406 DPRINTF(("esp_input: m_makewritable failed\n")); 407 ESP_STATINC(ESP_STAT_CRYPTO); 408 return error; 409 } 410 411 tc->tc_ptr = mtag; 412 413 if (esph) { 414 struct cryptodesc *crda = crp->crp_desc; 415 416 IPSEC_ASSERT(crda != NULL, ("esp_input: null ah crypto descriptor")); 417 418 /* Authentication descriptor */ 419 crda->crd_skip = skip; 420 if (espx && espx->type == CRYPTO_AES_GCM_16) 421 crda->crd_len = hlen - sav->ivlen; 422 else 423 crda->crd_len = m->m_pkthdr.len - (skip + alen); 424 crda->crd_inject = m->m_pkthdr.len - alen; 425 426 crda->crd_alg = esph->type; 427 if (espx && (espx->type == CRYPTO_AES_GCM_16 || 428 espx->type == CRYPTO_AES_GMAC)) { 429 crda->crd_key = _KEYBUF(sav->key_enc); 430 crda->crd_klen = _KEYBITS(sav->key_enc); 431 } else { 432 crda->crd_key = _KEYBUF(sav->key_auth); 433 crda->crd_klen = _KEYBITS(sav->key_auth); 434 } 435 436 /* Copy the authenticator */ 437 if (mtag == NULL) 438 m_copydata(m, m->m_pkthdr.len - alen, alen, 439 (tc + 1)); 440 441 /* Chain authentication request */ 442 crde = crda->crd_next; 443 } else { 444 crde = crp->crp_desc; 445 } 446 447 /* Crypto operation descriptor */ 448 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 449 crp->crp_flags = CRYPTO_F_IMBUF; 450 crp->crp_buf = m; 451 crp->crp_callback = esp_input_cb; 452 crp->crp_sid = sav->tdb_cryptoid; 453 crp->crp_opaque = tc; 454 455 /* These are passed as-is to the callback */ 456 tc->tc_spi = sav->spi; 457 tc->tc_dst = sav->sah->saidx.dst; 458 tc->tc_proto = sav->sah->saidx.proto; 459 tc->tc_protoff = protoff; 460 tc->tc_skip = skip; 461 462 /* Decryption descriptor */ 463 if (espx) { 464 IPSEC_ASSERT(crde != NULL, ("esp_input: null esp crypto descriptor")); 465 crde->crd_skip = skip + hlen; 466 if (espx->type == CRYPTO_AES_GMAC) 467 crde->crd_len = 0; 468 else 469 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 470 crde->crd_inject = skip + hlen - sav->ivlen; 471 472 crde->crd_alg = espx->type; 473 crde->crd_key = _KEYBUF(sav->key_enc); 474 crde->crd_klen = _KEYBITS(sav->key_enc); 475 /* XXX Rounds ? */ 476 } 477 478 if (mtag == NULL) 479 return crypto_dispatch(crp); 480 else 481 return esp_input_cb(crp); 482 } 483 484 #ifdef INET6 485 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \ 486 if (saidx->dst.sa.sa_family == AF_INET6) { \ 487 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \ 488 } else { \ 489 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \ 490 } \ 491 } while (0) 492 #else 493 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \ 494 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag)) 495 #endif 496 497 /* 498 * ESP input callback from the crypto driver. 499 */ 500 static int 501 esp_input_cb(struct cryptop *crp) 502 { 503 u_int8_t lastthree[3], aalg[AH_ALEN_MAX]; 504 int s, hlen, skip, protoff, error; 505 struct mbuf *m; 506 struct cryptodesc *crd; 507 const struct auth_hash *esph; 508 const struct enc_xform *espx; 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 espx = sav->tdb_encalgxform; 551 552 /* Check for crypto errors */ 553 if (crp->crp_etype) { 554 /* Reset the session ID */ 555 if (sav->tdb_cryptoid != 0) 556 sav->tdb_cryptoid = crp->crp_sid; 557 558 if (crp->crp_etype == EAGAIN) { 559 KEY_FREESAV(&sav); 560 mutex_exit(softnet_lock); 561 splx(s); 562 return crypto_dispatch(crp); 563 } 564 565 ESP_STATINC(ESP_STAT_NOXFORM); 566 DPRINTF(("esp_input_cb: crypto error %d\n", crp->crp_etype)); 567 error = crp->crp_etype; 568 goto bad; 569 } 570 571 /* Shouldn't happen... */ 572 if (m == NULL) { 573 ESP_STATINC(ESP_STAT_CRYPTO); 574 DPRINTF(("esp_input_cb: bogus returned buffer from crypto\n")); 575 error = EINVAL; 576 goto bad; 577 } 578 ESP_STATINC(ESP_STAT_HIST + sav->alg_enc); 579 580 /* If authentication was performed, check now. */ 581 if (esph != NULL) { 582 /* 583 * If we have a tag, it means an IPsec-aware NIC did 584 * the verification for us. Otherwise we need to 585 * check the authentication calculation. 586 */ 587 AH_STATINC(AH_STAT_HIST + sav->alg_auth); 588 if (mtag == NULL) { 589 /* Copy the authenticator from the packet */ 590 m_copydata(m, m->m_pkthdr.len - esph->authsize, 591 esph->authsize, aalg); 592 593 ptr = (tc + 1); 594 595 /* Verify authenticator */ 596 if (consttime_memequal(ptr, aalg, esph->authsize) 597 != 0) { 598 DPRINTF(("esp_input_cb: " 599 "authentication hash mismatch for packet in SA %s/%08lx\n", 600 ipsec_address(&saidx->dst), 601 (u_long) ntohl(sav->spi))); 602 ESP_STATINC(ESP_STAT_BADAUTH); 603 error = EACCES; 604 goto bad; 605 } 606 } 607 608 /* Remove trailing authenticator */ 609 m_adj(m, -(esph->authsize)); 610 } 611 612 /* Release the crypto descriptors */ 613 free(tc, M_XDATA), tc = NULL; 614 crypto_freereq(crp), crp = NULL; 615 616 /* 617 * Packet is now decrypted. 618 */ 619 m->m_flags |= M_DECRYPTED; 620 621 /* 622 * Update replay sequence number, if appropriate. 623 */ 624 if (sav->replay) { 625 u_int32_t seq; 626 627 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 628 sizeof (seq), &seq); 629 if (ipsec_updatereplay(ntohl(seq), sav)) { 630 DPRINTF(("%s: packet replay check for %s\n", __func__, 631 ipsec_logsastr(sav))); 632 ESP_STATINC(ESP_STAT_REPLAY); 633 error = ENOBUFS; 634 goto bad; 635 } 636 } 637 638 /* Determine the ESP header length */ 639 if (sav->flags & SADB_X_EXT_OLD) 640 hlen = sizeof (struct esp) + sav->ivlen; 641 else 642 hlen = sizeof (struct newesp) + sav->ivlen; 643 644 /* Remove the ESP header and IV from the mbuf. */ 645 error = m_striphdr(m, skip, hlen); 646 if (error) { 647 ESP_STATINC(ESP_STAT_HDROPS); 648 DPRINTF(("esp_input_cb: bad mbuf chain, SA %s/%08lx\n", 649 ipsec_address(&sav->sah->saidx.dst), 650 (u_long) ntohl(sav->spi))); 651 goto bad; 652 } 653 654 /* Save the last three bytes of decrypted data */ 655 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 656 657 /* Verify pad length */ 658 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 659 ESP_STATINC(ESP_STAT_BADILEN); 660 DPRINTF(("esp_input_cb: invalid padding length %d " 661 "for %u byte packet in SA %s/%08lx\n", 662 lastthree[1], m->m_pkthdr.len - skip, 663 ipsec_address(&sav->sah->saidx.dst), 664 (u_long) ntohl(sav->spi))); 665 error = EINVAL; 666 goto bad; 667 } 668 669 /* Verify correct decryption by checking the last padding bytes */ 670 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 671 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 672 ESP_STATINC(ESP_STAT_BADENC); 673 DPRINTF(("esp_input_cb: decryption failed " 674 "for packet in SA %s/%08lx\n", 675 ipsec_address(&sav->sah->saidx.dst), 676 (u_long) ntohl(sav->spi))); 677 DPRINTF(("esp_input_cb: %x %x\n", lastthree[0], lastthree[1])); 678 error = EINVAL; 679 goto bad; 680 } 681 } 682 683 /* Trim the mbuf chain to remove trailing authenticator and padding */ 684 m_adj(m, -(lastthree[1] + 2)); 685 686 /* Restore the Next Protocol field */ 687 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 688 689 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag); 690 691 KEY_FREESAV(&sav); 692 mutex_exit(softnet_lock); 693 splx(s); 694 return error; 695 bad: 696 if (sav) 697 KEY_FREESAV(&sav); 698 mutex_exit(softnet_lock); 699 splx(s); 700 if (m != NULL) 701 m_freem(m); 702 if (tc != NULL) 703 free(tc, M_XDATA); 704 if (crp != NULL) 705 crypto_freereq(crp); 706 return error; 707 } 708 709 /* 710 * ESP output routine, called by ipsec[46]_process_packet(). 711 */ 712 static int 713 esp_output( 714 struct mbuf *m, 715 struct ipsecrequest *isr, 716 struct mbuf **mp, 717 int skip, 718 int protoff 719 ) 720 { 721 const struct enc_xform *espx; 722 const struct auth_hash *esph; 723 int hlen, rlen, plen, padding, blks, alen, i, roff; 724 struct mbuf *mo = NULL; 725 struct tdb_crypto *tc; 726 const struct secasvar *sav; 727 struct secasindex *saidx; 728 unsigned char *pad; 729 u_int8_t prot; 730 int error, maxpacketsize; 731 732 struct cryptodesc *crde = NULL, *crda = NULL; 733 struct cryptop *crp; 734 735 IPSEC_SPLASSERT_SOFTNET("esp_output"); 736 737 sav = isr->sav; 738 IPSEC_ASSERT(sav != NULL, ("esp_output: null SA")); 739 esph = sav->tdb_authalgxform; 740 espx = sav->tdb_encalgxform; 741 IPSEC_ASSERT(espx != NULL, ("esp_output: null encoding xform")); 742 743 if (sav->flags & SADB_X_EXT_OLD) 744 hlen = sizeof (struct esp) + sav->ivlen; 745 else 746 hlen = sizeof (struct newesp) + sav->ivlen; 747 748 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 749 /* 750 * NB: The null encoding transform has a blocksize of 4 751 * so that headers are properly aligned. 752 */ 753 blks = espx->blocksize; /* IV blocksize */ 754 755 /* XXX clamp padding length a la KAME??? */ 756 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 757 plen = rlen + padding; /* Padded payload length. */ 758 759 if (esph) 760 alen = esph->authsize; 761 else 762 alen = 0; 763 764 ESP_STATINC(ESP_STAT_OUTPUT); 765 766 saidx = &sav->sah->saidx; 767 /* Check for maximum packet size violations. */ 768 switch (saidx->dst.sa.sa_family) { 769 #ifdef INET 770 case AF_INET: 771 maxpacketsize = IP_MAXPACKET; 772 break; 773 #endif /* INET */ 774 #ifdef INET6 775 case AF_INET6: 776 maxpacketsize = IPV6_MAXPACKET; 777 break; 778 #endif /* INET6 */ 779 default: 780 DPRINTF(("esp_output: unknown/unsupported protocol " 781 "family %d, SA %s/%08lx\n", 782 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst), 783 (u_long) ntohl(sav->spi))); 784 ESP_STATINC(ESP_STAT_NOPF); 785 error = EPFNOSUPPORT; 786 goto bad; 787 } 788 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 789 DPRINTF(("esp_output: packet in SA %s/%08lx got too big " 790 "(len %u, max len %u)\n", 791 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi), 792 skip + hlen + rlen + padding + alen, maxpacketsize)); 793 ESP_STATINC(ESP_STAT_TOOBIG); 794 error = EMSGSIZE; 795 goto bad; 796 } 797 798 /* Update the counters. */ 799 ESP_STATADD(ESP_STAT_OBYTES, m->m_pkthdr.len - skip); 800 801 m = m_clone(m); 802 if (m == NULL) { 803 DPRINTF(("esp_output: cannot clone mbuf chain, SA %s/%08lx\n", 804 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 805 ESP_STATINC(ESP_STAT_HDROPS); 806 error = ENOBUFS; 807 goto bad; 808 } 809 810 /* Inject ESP header. */ 811 mo = m_makespace(m, skip, hlen, &roff); 812 if (mo == NULL) { 813 DPRINTF(("esp_output: failed to inject %u byte ESP hdr for SA " 814 "%s/%08lx\n", 815 hlen, ipsec_address(&saidx->dst), 816 (u_long) ntohl(sav->spi))); 817 ESP_STATINC(ESP_STAT_HDROPS); /* XXX diffs from openbsd */ 818 error = ENOBUFS; 819 goto bad; 820 } 821 822 /* Initialize ESP header. */ 823 memcpy(mtod(mo, char *) + roff, &sav->spi, sizeof(u_int32_t)); 824 if (sav->replay) { 825 u_int32_t replay; 826 827 #ifdef IPSEC_DEBUG 828 /* Emulate replay attack when ipsec_replay is TRUE. */ 829 if (!ipsec_replay) 830 #endif 831 sav->replay->count++; 832 833 replay = htonl(sav->replay->count); 834 bcopy(&replay, 835 mtod(mo,char *) + roff + sizeof(u_int32_t), 836 sizeof(u_int32_t)); 837 } 838 839 /* 840 * Add padding -- better to do it ourselves than use the crypto engine, 841 * although if/when we support compression, we'd have to do that. 842 */ 843 pad = (u_char *) m_pad(m, padding + alen); 844 if (pad == NULL) { 845 DPRINTF(("esp_output: m_pad failed for SA %s/%08lx\n", 846 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 847 m = NULL; /* NB: free'd by m_pad */ 848 error = ENOBUFS; 849 goto bad; 850 } 851 852 /* 853 * Add padding: random, zero, or self-describing. 854 * XXX catch unexpected setting 855 */ 856 switch (sav->flags & SADB_X_EXT_PMASK) { 857 case SADB_X_EXT_PRAND: 858 (void) read_random(pad, padding - 2); 859 break; 860 case SADB_X_EXT_PZERO: 861 memset(pad, 0, padding - 2); 862 break; 863 case SADB_X_EXT_PSEQ: 864 for (i = 0; i < padding - 2; i++) 865 pad[i] = i+1; 866 break; 867 } 868 869 /* Fix padding length and Next Protocol in padding itself. */ 870 pad[padding - 2] = padding - 2; 871 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 872 873 /* Fix Next Protocol in IPv4/IPv6 header. */ 874 prot = IPPROTO_ESP; 875 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 876 877 /* Get crypto descriptors. */ 878 crp = crypto_getreq(esph && espx ? 2 : 1); 879 if (crp == NULL) { 880 DPRINTF(("esp_output: failed to acquire crypto descriptors\n")); 881 ESP_STATINC(ESP_STAT_CRYPTO); 882 error = ENOBUFS; 883 goto bad; 884 } 885 886 if (espx) { 887 crde = crp->crp_desc; 888 crda = crde->crd_next; 889 890 /* Encryption descriptor. */ 891 crde->crd_skip = skip + hlen; 892 if (espx->type == CRYPTO_AES_GMAC) 893 crde->crd_len = 0; 894 else 895 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 896 crde->crd_flags = CRD_F_ENCRYPT; 897 crde->crd_inject = skip + hlen - sav->ivlen; 898 899 /* Encryption operation. */ 900 crde->crd_alg = espx->type; 901 crde->crd_key = _KEYBUF(sav->key_enc); 902 crde->crd_klen = _KEYBITS(sav->key_enc); 903 /* XXX Rounds ? */ 904 } else 905 crda = crp->crp_desc; 906 907 /* IPsec-specific opaque crypto info. */ 908 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 909 M_XDATA, M_NOWAIT|M_ZERO); 910 if (tc == NULL) { 911 crypto_freereq(crp); 912 DPRINTF(("esp_output: failed to allocate tdb_crypto\n")); 913 ESP_STATINC(ESP_STAT_CRYPTO); 914 error = ENOBUFS; 915 goto bad; 916 } 917 918 /* Callback parameters */ 919 tc->tc_isr = isr; 920 tc->tc_spi = sav->spi; 921 tc->tc_dst = saidx->dst; 922 tc->tc_proto = saidx->proto; 923 924 /* Crypto operation descriptor. */ 925 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 926 crp->crp_flags = CRYPTO_F_IMBUF; 927 crp->crp_buf = m; 928 crp->crp_callback = esp_output_cb; 929 crp->crp_opaque = tc; 930 crp->crp_sid = sav->tdb_cryptoid; 931 932 if (esph) { 933 /* Authentication descriptor. */ 934 crda->crd_skip = skip; 935 if (espx && espx->type == CRYPTO_AES_GCM_16) 936 crda->crd_len = hlen - sav->ivlen; 937 else 938 crda->crd_len = m->m_pkthdr.len - (skip + alen); 939 crda->crd_inject = m->m_pkthdr.len - alen; 940 941 /* Authentication operation. */ 942 crda->crd_alg = esph->type; 943 if (espx && (espx->type == CRYPTO_AES_GCM_16 || 944 espx->type == CRYPTO_AES_GMAC)) { 945 crda->crd_key = _KEYBUF(sav->key_enc); 946 crda->crd_klen = _KEYBITS(sav->key_enc); 947 } else { 948 crda->crd_key = _KEYBUF(sav->key_auth); 949 crda->crd_klen = _KEYBITS(sav->key_auth); 950 } 951 } 952 953 return crypto_dispatch(crp); 954 bad: 955 if (m) 956 m_freem(m); 957 return (error); 958 } 959 960 /* 961 * ESP output callback from the crypto driver. 962 */ 963 static int 964 esp_output_cb(struct cryptop *crp) 965 { 966 struct tdb_crypto *tc; 967 struct ipsecrequest *isr; 968 struct secasvar *sav; 969 struct mbuf *m; 970 int s, err, error; 971 972 tc = (struct tdb_crypto *) crp->crp_opaque; 973 IPSEC_ASSERT(tc != NULL, ("esp_output_cb: null opaque data area!")); 974 m = (struct mbuf *) crp->crp_buf; 975 976 s = splsoftnet(); 977 mutex_enter(softnet_lock); 978 979 isr = tc->tc_isr; 980 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi, 0, 0); 981 if (sav == NULL) { 982 ESP_STATINC(ESP_STAT_NOTDB); 983 DPRINTF(("esp_output_cb: SA expired while in crypto " 984 "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst), 985 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 986 error = ENOBUFS; /*XXX*/ 987 goto bad; 988 } 989 IPSEC_ASSERT(isr->sav == sav, 990 ("esp_output_cb: SA changed was %p now %p\n", isr->sav, sav)); 991 992 /* Check for crypto errors. */ 993 if (crp->crp_etype) { 994 /* Reset session ID. */ 995 if (sav->tdb_cryptoid != 0) 996 sav->tdb_cryptoid = crp->crp_sid; 997 998 if (crp->crp_etype == EAGAIN) { 999 KEY_FREESAV(&sav); 1000 mutex_exit(softnet_lock); 1001 splx(s); 1002 return crypto_dispatch(crp); 1003 } 1004 1005 ESP_STATINC(ESP_STAT_NOXFORM); 1006 DPRINTF(("esp_output_cb: crypto error %d\n", crp->crp_etype)); 1007 error = crp->crp_etype; 1008 goto bad; 1009 } 1010 1011 /* Shouldn't happen... */ 1012 if (m == NULL) { 1013 ESP_STATINC(ESP_STAT_CRYPTO); 1014 DPRINTF(("esp_output_cb: bogus returned buffer from crypto\n")); 1015 error = EINVAL; 1016 goto bad; 1017 } 1018 ESP_STATINC(ESP_STAT_HIST + sav->alg_enc); 1019 if (sav->tdb_authalgxform != NULL) 1020 AH_STATINC(AH_STAT_HIST + sav->alg_auth); 1021 1022 /* Release crypto descriptors. */ 1023 free(tc, M_XDATA); 1024 crypto_freereq(crp); 1025 1026 #ifdef IPSEC_DEBUG 1027 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 1028 if (ipsec_integrity) { 1029 static unsigned char ipseczeroes[AH_ALEN_MAX]; 1030 const struct auth_hash *esph; 1031 1032 /* 1033 * Corrupt HMAC if we want to test integrity verification of 1034 * the other side. 1035 */ 1036 esph = sav->tdb_authalgxform; 1037 if (esph != NULL) { 1038 m_copyback(m, m->m_pkthdr.len - esph->authsize, 1039 esph->authsize, ipseczeroes); 1040 } 1041 } 1042 #endif 1043 1044 /* NB: m is reclaimed by ipsec_process_done. */ 1045 err = ipsec_process_done(m, isr); 1046 KEY_FREESAV(&sav); 1047 mutex_exit(softnet_lock); 1048 splx(s); 1049 return err; 1050 bad: 1051 if (sav) 1052 KEY_FREESAV(&sav); 1053 mutex_exit(softnet_lock); 1054 splx(s); 1055 if (m) 1056 m_freem(m); 1057 free(tc, M_XDATA); 1058 crypto_freereq(crp); 1059 return error; 1060 } 1061 1062 static struct xformsw esp_xformsw = { 1063 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 1064 esp_init, esp_zeroize, esp_input, 1065 esp_output, 1066 NULL, 1067 }; 1068 1069 INITFN void 1070 esp_attach(void) 1071 { 1072 1073 espstat_percpu = percpu_alloc(sizeof(uint64_t) * ESP_NSTATS); 1074 1075 #define MAXIV(xform) \ 1076 if (xform.ivsize > esp_max_ivlen) \ 1077 esp_max_ivlen = xform.ivsize \ 1078 1079 esp_max_ivlen = 0; 1080 MAXIV(enc_xform_des); /* SADB_EALG_DESCBC */ 1081 MAXIV(enc_xform_3des); /* SADB_EALG_3DESCBC */ 1082 MAXIV(enc_xform_rijndael128); /* SADB_X_EALG_AES */ 1083 MAXIV(enc_xform_blf); /* SADB_X_EALG_BLOWFISHCBC */ 1084 MAXIV(enc_xform_cast5); /* SADB_X_EALG_CAST128CBC */ 1085 MAXIV(enc_xform_skipjack); /* SADB_X_EALG_SKIPJACK */ 1086 MAXIV(enc_xform_camellia); /* SADB_X_EALG_CAMELLIACBC */ 1087 MAXIV(enc_xform_aes_ctr); /* SADB_X_EALG_AESCTR */ 1088 MAXIV(enc_xform_null); /* SADB_EALG_NULL */ 1089 1090 xform_register(&esp_xformsw); 1091 #undef MAXIV 1092 } 1093 #ifdef __FreeBSD__ 1094 SYSINIT(esp_xform_init, SI_SUB_DRIVERS, SI_ORDER_FIRST, esp_attach, NULL) 1095 #else 1096 #endif 1097