1 /* $NetBSD: xform_esp.c,v 1.38 2011/05/26 21:50:02 drochner 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 1.38 2011/05/26 21:50:02 drochner 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; 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 tc->tc_ptr = mtag; 402 403 if (esph) { 404 struct cryptodesc *crda = crp->crp_desc; 405 406 IPSEC_ASSERT(crda != NULL, ("esp_input: null ah crypto descriptor")); 407 408 /* Authentication descriptor */ 409 crda->crd_skip = skip; 410 if (espx && espx->type == CRYPTO_AES_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_GCM_16 || 418 espx->type == CRYPTO_AES_GMAC)) { 419 crda->crd_key = _KEYBUF(sav->key_enc); 420 crda->crd_klen = _KEYBITS(sav->key_enc); 421 } else { 422 crda->crd_key = _KEYBUF(sav->key_auth); 423 crda->crd_klen = _KEYBITS(sav->key_auth); 424 } 425 426 /* Copy the authenticator */ 427 if (mtag == NULL) 428 m_copydata(m, m->m_pkthdr.len - alen, alen, 429 (tc + 1)); 430 431 /* Chain authentication request */ 432 crde = crda->crd_next; 433 } else { 434 crde = crp->crp_desc; 435 } 436 437 /* Crypto operation descriptor */ 438 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 439 crp->crp_flags = CRYPTO_F_IMBUF; 440 crp->crp_buf = m; 441 crp->crp_callback = esp_input_cb; 442 crp->crp_sid = sav->tdb_cryptoid; 443 crp->crp_opaque = tc; 444 445 /* These are passed as-is to the callback */ 446 tc->tc_spi = sav->spi; 447 tc->tc_dst = sav->sah->saidx.dst; 448 tc->tc_proto = sav->sah->saidx.proto; 449 tc->tc_protoff = protoff; 450 tc->tc_skip = skip; 451 452 /* Decryption descriptor */ 453 if (espx) { 454 IPSEC_ASSERT(crde != NULL, ("esp_input: null esp crypto descriptor")); 455 crde->crd_skip = skip + hlen; 456 if (espx->type == CRYPTO_AES_GMAC) 457 crde->crd_len = 0; 458 else 459 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 460 crde->crd_inject = skip + hlen - sav->ivlen; 461 462 crde->crd_alg = espx->type; 463 crde->crd_key = _KEYBUF(sav->key_enc); 464 crde->crd_klen = _KEYBITS(sav->key_enc); 465 /* XXX Rounds ? */ 466 } 467 468 if (mtag == NULL) 469 return crypto_dispatch(crp); 470 else 471 return esp_input_cb(crp); 472 } 473 474 #ifdef INET6 475 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \ 476 if (saidx->dst.sa.sa_family == AF_INET6) { \ 477 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \ 478 } else { \ 479 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \ 480 } \ 481 } while (0) 482 #else 483 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \ 484 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag)) 485 #endif 486 487 /* 488 * ESP input callback from the crypto driver. 489 */ 490 static int 491 esp_input_cb(struct cryptop *crp) 492 { 493 u_int8_t lastthree[3], aalg[AH_ALEN_MAX]; 494 int s, hlen, skip, protoff, error; 495 struct mbuf *m; 496 struct cryptodesc *crd; 497 const struct auth_hash *esph; 498 const struct enc_xform *espx; 499 struct tdb_crypto *tc; 500 struct m_tag *mtag; 501 struct secasvar *sav; 502 struct secasindex *saidx; 503 void *ptr; 504 u_int16_t dport = 0; 505 u_int16_t sport = 0; 506 #ifdef IPSEC_NAT_T 507 struct m_tag * tag = NULL; 508 #endif 509 510 crd = crp->crp_desc; 511 IPSEC_ASSERT(crd != NULL, ("esp_input_cb: null crypto descriptor!")); 512 513 tc = (struct tdb_crypto *) crp->crp_opaque; 514 IPSEC_ASSERT(tc != NULL, ("esp_input_cb: null opaque crypto data area!")); 515 skip = tc->tc_skip; 516 protoff = tc->tc_protoff; 517 mtag = (struct m_tag *) tc->tc_ptr; 518 m = (struct mbuf *) crp->crp_buf; 519 520 #ifdef IPSEC_NAT_T 521 /* find the source port for NAT-T */ 522 if ((tag = m_tag_find(m, PACKET_TAG_IPSEC_NAT_T_PORTS, NULL))) { 523 sport = ((u_int16_t *)(tag + 1))[0]; 524 dport = ((u_int16_t *)(tag + 1))[1]; 525 } 526 #endif 527 528 s = splsoftnet(); 529 mutex_enter(softnet_lock); 530 531 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi, sport, dport); 532 if (sav == NULL) { 533 ESP_STATINC(ESP_STAT_NOTDB); 534 DPRINTF(("esp_input_cb: SA expired while in crypto " 535 "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst), 536 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 537 error = ENOBUFS; /*XXX*/ 538 goto bad; 539 } 540 541 saidx = &sav->sah->saidx; 542 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 543 saidx->dst.sa.sa_family == AF_INET6, 544 ("esp_input_cb: unexpected protocol family %u", 545 saidx->dst.sa.sa_family)); 546 547 esph = sav->tdb_authalgxform; 548 espx = sav->tdb_encalgxform; 549 550 /* Check for crypto errors */ 551 if (crp->crp_etype) { 552 /* Reset the session ID */ 553 if (sav->tdb_cryptoid != 0) 554 sav->tdb_cryptoid = crp->crp_sid; 555 556 if (crp->crp_etype == EAGAIN) { 557 KEY_FREESAV(&sav); 558 mutex_exit(softnet_lock); 559 splx(s); 560 return crypto_dispatch(crp); 561 } 562 563 ESP_STATINC(ESP_STAT_NOXFORM); 564 DPRINTF(("esp_input_cb: crypto error %d\n", crp->crp_etype)); 565 error = crp->crp_etype; 566 goto bad; 567 } 568 569 /* Shouldn't happen... */ 570 if (m == NULL) { 571 ESP_STATINC(ESP_STAT_CRYPTO); 572 DPRINTF(("esp_input_cb: bogus returned buffer from crypto\n")); 573 error = EINVAL; 574 goto bad; 575 } 576 ESP_STATINC(ESP_STAT_HIST + sav->alg_enc); 577 578 /* If authentication was performed, check now. */ 579 if (esph != NULL) { 580 /* 581 * If we have a tag, it means an IPsec-aware NIC did 582 * the verification for us. Otherwise we need to 583 * check the authentication calculation. 584 */ 585 AH_STATINC(AH_STAT_HIST + sav->alg_auth); 586 if (mtag == NULL) { 587 /* Copy the authenticator from the packet */ 588 m_copydata(m, m->m_pkthdr.len - esph->authsize, 589 esph->authsize, aalg); 590 591 ptr = (tc + 1); 592 593 /* Verify authenticator */ 594 if (memcmp(ptr, aalg, esph->authsize) != 0) { 595 DPRINTF(("esp_input_cb: " 596 "authentication hash mismatch for packet in SA %s/%08lx\n", 597 ipsec_address(&saidx->dst), 598 (u_long) ntohl(sav->spi))); 599 ESP_STATINC(ESP_STAT_BADAUTH); 600 error = EACCES; 601 goto bad; 602 } 603 } 604 605 /* Remove trailing authenticator */ 606 m_adj(m, -(esph->authsize)); 607 } 608 609 /* Release the crypto descriptors */ 610 free(tc, M_XDATA), tc = NULL; 611 crypto_freereq(crp), crp = NULL; 612 613 /* 614 * Packet is now decrypted. 615 */ 616 m->m_flags |= M_DECRYPTED; 617 618 /* 619 * Update replay sequence number, if appropriate. 620 */ 621 if (sav->replay) { 622 u_int32_t seq; 623 624 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 625 sizeof (seq), &seq); 626 if (ipsec_updatereplay(ntohl(seq), sav)) { 627 DPRINTF(("%s: packet replay check for %s\n", __func__, 628 ipsec_logsastr(sav))); 629 ESP_STATINC(ESP_STAT_REPLAY); 630 error = ENOBUFS; 631 goto bad; 632 } 633 } 634 635 /* Determine the ESP header length */ 636 if (sav->flags & SADB_X_EXT_OLD) 637 hlen = sizeof (struct esp) + sav->ivlen; 638 else 639 hlen = sizeof (struct newesp) + sav->ivlen; 640 641 /* Remove the ESP header and IV from the mbuf. */ 642 error = m_striphdr(m, skip, hlen); 643 if (error) { 644 ESP_STATINC(ESP_STAT_HDROPS); 645 DPRINTF(("esp_input_cb: bad mbuf chain, SA %s/%08lx\n", 646 ipsec_address(&sav->sah->saidx.dst), 647 (u_long) ntohl(sav->spi))); 648 goto bad; 649 } 650 651 /* Save the last three bytes of decrypted data */ 652 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 653 654 /* Verify pad length */ 655 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 656 ESP_STATINC(ESP_STAT_BADILEN); 657 DPRINTF(("esp_input_cb: invalid padding length %d " 658 "for %u byte packet in SA %s/%08lx\n", 659 lastthree[1], m->m_pkthdr.len - skip, 660 ipsec_address(&sav->sah->saidx.dst), 661 (u_long) ntohl(sav->spi))); 662 error = EINVAL; 663 goto bad; 664 } 665 666 /* Verify correct decryption by checking the last padding bytes */ 667 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 668 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 669 ESP_STATINC(ESP_STAT_BADENC); 670 DPRINTF(("esp_input_cb: decryption failed " 671 "for packet in SA %s/%08lx\n", 672 ipsec_address(&sav->sah->saidx.dst), 673 (u_long) ntohl(sav->spi))); 674 DPRINTF(("esp_input_cb: %x %x\n", lastthree[0], lastthree[1])); 675 error = EINVAL; 676 goto bad; 677 } 678 } 679 680 /* Trim the mbuf chain to remove trailing authenticator and padding */ 681 m_adj(m, -(lastthree[1] + 2)); 682 683 /* Restore the Next Protocol field */ 684 m = m_copyback_cow(m, protoff, sizeof (u_int8_t), lastthree + 2, 685 M_DONTWAIT); 686 687 if (m == NULL) { 688 ESP_STATINC(ESP_STAT_CRYPTO); 689 DPRINTF(("esp_input_cb: failed to allocate mbuf\n")); 690 error = ENOBUFS; 691 goto bad; 692 } 693 694 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag); 695 696 KEY_FREESAV(&sav); 697 mutex_exit(softnet_lock); 698 splx(s); 699 return error; 700 bad: 701 if (sav) 702 KEY_FREESAV(&sav); 703 mutex_exit(softnet_lock); 704 splx(s); 705 if (m != NULL) 706 m_freem(m); 707 if (tc != NULL) 708 free(tc, M_XDATA); 709 if (crp != NULL) 710 crypto_freereq(crp); 711 return error; 712 } 713 714 /* 715 * ESP output routine, called by ipsec[46]_process_packet(). 716 */ 717 static int 718 esp_output( 719 struct mbuf *m, 720 struct ipsecrequest *isr, 721 struct mbuf **mp, 722 int skip, 723 int protoff 724 ) 725 { 726 const struct enc_xform *espx; 727 const struct auth_hash *esph; 728 int hlen, rlen, plen, padding, blks, alen, i, roff; 729 struct mbuf *mo = (struct mbuf *) NULL; 730 struct tdb_crypto *tc; 731 const struct secasvar *sav; 732 struct secasindex *saidx; 733 unsigned char *pad; 734 u_int8_t prot; 735 int error, maxpacketsize; 736 737 struct cryptodesc *crde = NULL, *crda = NULL; 738 struct cryptop *crp; 739 740 IPSEC_SPLASSERT_SOFTNET("esp_output"); 741 742 sav = isr->sav; 743 IPSEC_ASSERT(sav != NULL, ("esp_output: null SA")); 744 esph = sav->tdb_authalgxform; 745 espx = sav->tdb_encalgxform; 746 IPSEC_ASSERT(espx != NULL, ("esp_output: null encoding xform")); 747 748 if (sav->flags & SADB_X_EXT_OLD) 749 hlen = sizeof (struct esp) + sav->ivlen; 750 else 751 hlen = sizeof (struct newesp) + sav->ivlen; 752 753 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 754 /* 755 * NB: The null encoding transform has a blocksize of 4 756 * so that headers are properly aligned. 757 */ 758 blks = espx->blocksize; /* IV blocksize */ 759 760 /* XXX clamp padding length a la KAME??? */ 761 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 762 plen = rlen + padding; /* Padded payload length. */ 763 764 if (esph) 765 alen = esph->authsize; 766 else 767 alen = 0; 768 769 ESP_STATINC(ESP_STAT_OUTPUT); 770 771 saidx = &sav->sah->saidx; 772 /* Check for maximum packet size violations. */ 773 switch (saidx->dst.sa.sa_family) { 774 #ifdef INET 775 case AF_INET: 776 maxpacketsize = IP_MAXPACKET; 777 break; 778 #endif /* INET */ 779 #ifdef INET6 780 case AF_INET6: 781 maxpacketsize = IPV6_MAXPACKET; 782 break; 783 #endif /* INET6 */ 784 default: 785 DPRINTF(("esp_output: unknown/unsupported protocol " 786 "family %d, SA %s/%08lx\n", 787 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst), 788 (u_long) ntohl(sav->spi))); 789 ESP_STATINC(ESP_STAT_NOPF); 790 error = EPFNOSUPPORT; 791 goto bad; 792 } 793 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 794 DPRINTF(("esp_output: packet in SA %s/%08lx got too big " 795 "(len %u, max len %u)\n", 796 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi), 797 skip + hlen + rlen + padding + alen, maxpacketsize)); 798 ESP_STATINC(ESP_STAT_TOOBIG); 799 error = EMSGSIZE; 800 goto bad; 801 } 802 803 /* Update the counters. */ 804 ESP_STATADD(ESP_STAT_OBYTES, m->m_pkthdr.len - skip); 805 806 m = m_clone(m); 807 if (m == NULL) { 808 DPRINTF(("esp_output: cannot clone mbuf chain, SA %s/%08lx\n", 809 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 810 ESP_STATINC(ESP_STAT_HDROPS); 811 error = ENOBUFS; 812 goto bad; 813 } 814 815 /* Inject ESP header. */ 816 mo = m_makespace(m, skip, hlen, &roff); 817 if (mo == NULL) { 818 DPRINTF(("esp_output: failed to inject %u byte ESP hdr for SA " 819 "%s/%08lx\n", 820 hlen, ipsec_address(&saidx->dst), 821 (u_long) ntohl(sav->spi))); 822 ESP_STATINC(ESP_STAT_HDROPS); /* XXX diffs from openbsd */ 823 error = ENOBUFS; 824 goto bad; 825 } 826 827 /* Initialize ESP header. */ 828 memcpy(mtod(mo, char *) + roff, &sav->spi, sizeof(u_int32_t)); 829 if (sav->replay) { 830 u_int32_t replay; 831 832 #ifdef IPSEC_DEBUG 833 /* Emulate replay attack when ipsec_replay is TRUE. */ 834 if (!ipsec_replay) 835 #endif 836 sav->replay->count++; 837 838 replay = htonl(sav->replay->count); 839 bcopy(&replay, 840 mtod(mo,char *) + roff + sizeof(u_int32_t), 841 sizeof(u_int32_t)); 842 } 843 844 /* 845 * Add padding -- better to do it ourselves than use the crypto engine, 846 * although if/when we support compression, we'd have to do that. 847 */ 848 pad = (u_char *) m_pad(m, padding + alen); 849 if (pad == NULL) { 850 DPRINTF(("esp_output: m_pad failed for SA %s/%08lx\n", 851 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 852 m = NULL; /* NB: free'd by m_pad */ 853 error = ENOBUFS; 854 goto bad; 855 } 856 857 /* 858 * Add padding: random, zero, or self-describing. 859 * XXX catch unexpected setting 860 */ 861 switch (sav->flags & SADB_X_EXT_PMASK) { 862 case SADB_X_EXT_PRAND: 863 (void) read_random(pad, padding - 2); 864 break; 865 case SADB_X_EXT_PZERO: 866 memset(pad, 0, padding - 2); 867 break; 868 case SADB_X_EXT_PSEQ: 869 for (i = 0; i < padding - 2; i++) 870 pad[i] = i+1; 871 break; 872 } 873 874 /* Fix padding length and Next Protocol in padding itself. */ 875 pad[padding - 2] = padding - 2; 876 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 877 878 /* Fix Next Protocol in IPv4/IPv6 header. */ 879 prot = IPPROTO_ESP; 880 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 881 882 /* Get crypto descriptors. */ 883 crp = crypto_getreq(esph && espx ? 2 : 1); 884 if (crp == NULL) { 885 DPRINTF(("esp_output: failed to acquire crypto descriptors\n")); 886 ESP_STATINC(ESP_STAT_CRYPTO); 887 error = ENOBUFS; 888 goto bad; 889 } 890 891 if (espx) { 892 crde = crp->crp_desc; 893 crda = crde->crd_next; 894 895 /* Encryption descriptor. */ 896 crde->crd_skip = skip + hlen; 897 if (espx->type == CRYPTO_AES_GMAC) 898 crde->crd_len = 0; 899 else 900 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 901 crde->crd_flags = CRD_F_ENCRYPT; 902 crde->crd_inject = skip + hlen - sav->ivlen; 903 904 /* Encryption operation. */ 905 crde->crd_alg = espx->type; 906 crde->crd_key = _KEYBUF(sav->key_enc); 907 crde->crd_klen = _KEYBITS(sav->key_enc); 908 /* XXX Rounds ? */ 909 } else 910 crda = crp->crp_desc; 911 912 /* IPsec-specific opaque crypto info. */ 913 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 914 M_XDATA, M_NOWAIT|M_ZERO); 915 if (tc == NULL) { 916 crypto_freereq(crp); 917 DPRINTF(("esp_output: failed to allocate tdb_crypto\n")); 918 ESP_STATINC(ESP_STAT_CRYPTO); 919 error = ENOBUFS; 920 goto bad; 921 } 922 923 /* Callback parameters */ 924 tc->tc_isr = isr; 925 tc->tc_spi = sav->spi; 926 tc->tc_dst = saidx->dst; 927 tc->tc_proto = saidx->proto; 928 929 /* Crypto operation descriptor. */ 930 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 931 crp->crp_flags = CRYPTO_F_IMBUF; 932 crp->crp_buf = m; 933 crp->crp_callback = esp_output_cb; 934 crp->crp_opaque = tc; 935 crp->crp_sid = sav->tdb_cryptoid; 936 937 if (esph) { 938 /* Authentication descriptor. */ 939 crda->crd_skip = skip; 940 if (espx && espx->type == CRYPTO_AES_GCM_16) 941 crda->crd_len = hlen - sav->ivlen; 942 else 943 crda->crd_len = m->m_pkthdr.len - (skip + alen); 944 crda->crd_inject = m->m_pkthdr.len - alen; 945 946 /* Authentication operation. */ 947 crda->crd_alg = esph->type; 948 if (espx && (espx->type == CRYPTO_AES_GCM_16 || 949 espx->type == CRYPTO_AES_GMAC)) { 950 crda->crd_key = _KEYBUF(sav->key_enc); 951 crda->crd_klen = _KEYBITS(sav->key_enc); 952 } else { 953 crda->crd_key = _KEYBUF(sav->key_auth); 954 crda->crd_klen = _KEYBITS(sav->key_auth); 955 } 956 } 957 958 return crypto_dispatch(crp); 959 bad: 960 if (m) 961 m_freem(m); 962 return (error); 963 } 964 965 /* 966 * ESP output callback from the crypto driver. 967 */ 968 static int 969 esp_output_cb(struct cryptop *crp) 970 { 971 struct tdb_crypto *tc; 972 struct ipsecrequest *isr; 973 struct secasvar *sav; 974 struct mbuf *m; 975 int s, err, error; 976 977 tc = (struct tdb_crypto *) crp->crp_opaque; 978 IPSEC_ASSERT(tc != NULL, ("esp_output_cb: null opaque data area!")); 979 m = (struct mbuf *) crp->crp_buf; 980 981 s = splsoftnet(); 982 mutex_enter(softnet_lock); 983 984 isr = tc->tc_isr; 985 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi, 0, 0); 986 if (sav == NULL) { 987 ESP_STATINC(ESP_STAT_NOTDB); 988 DPRINTF(("esp_output_cb: SA expired while in crypto " 989 "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst), 990 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 991 error = ENOBUFS; /*XXX*/ 992 goto bad; 993 } 994 IPSEC_ASSERT(isr->sav == sav, 995 ("esp_output_cb: SA changed was %p now %p\n", isr->sav, sav)); 996 997 /* Check for crypto errors. */ 998 if (crp->crp_etype) { 999 /* Reset session ID. */ 1000 if (sav->tdb_cryptoid != 0) 1001 sav->tdb_cryptoid = crp->crp_sid; 1002 1003 if (crp->crp_etype == EAGAIN) { 1004 KEY_FREESAV(&sav); 1005 mutex_exit(softnet_lock); 1006 splx(s); 1007 return crypto_dispatch(crp); 1008 } 1009 1010 ESP_STATINC(ESP_STAT_NOXFORM); 1011 DPRINTF(("esp_output_cb: crypto error %d\n", crp->crp_etype)); 1012 error = crp->crp_etype; 1013 goto bad; 1014 } 1015 1016 /* Shouldn't happen... */ 1017 if (m == NULL) { 1018 ESP_STATINC(ESP_STAT_CRYPTO); 1019 DPRINTF(("esp_output_cb: bogus returned buffer from crypto\n")); 1020 error = EINVAL; 1021 goto bad; 1022 } 1023 ESP_STATINC(ESP_STAT_HIST + sav->alg_enc); 1024 if (sav->tdb_authalgxform != NULL) 1025 AH_STATINC(AH_STAT_HIST + sav->alg_auth); 1026 1027 /* Release crypto descriptors. */ 1028 free(tc, M_XDATA); 1029 crypto_freereq(crp); 1030 1031 #ifdef IPSEC_DEBUG 1032 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 1033 if (ipsec_integrity) { 1034 static unsigned char ipseczeroes[AH_ALEN_MAX]; 1035 const struct auth_hash *esph; 1036 1037 /* 1038 * Corrupt HMAC if we want to test integrity verification of 1039 * the other side. 1040 */ 1041 esph = sav->tdb_authalgxform; 1042 if (esph != NULL) { 1043 m_copyback(m, m->m_pkthdr.len - esph->authsize, 1044 esph->authsize, ipseczeroes); 1045 } 1046 } 1047 #endif 1048 1049 /* NB: m is reclaimed by ipsec_process_done. */ 1050 err = ipsec_process_done(m, isr); 1051 KEY_FREESAV(&sav); 1052 mutex_exit(softnet_lock); 1053 splx(s); 1054 return err; 1055 bad: 1056 if (sav) 1057 KEY_FREESAV(&sav); 1058 mutex_exit(softnet_lock); 1059 splx(s); 1060 if (m) 1061 m_freem(m); 1062 free(tc, M_XDATA); 1063 crypto_freereq(crp); 1064 return error; 1065 } 1066 1067 static struct xformsw esp_xformsw = { 1068 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 1069 esp_init, esp_zeroize, esp_input, 1070 esp_output, 1071 NULL, 1072 }; 1073 1074 INITFN void 1075 esp_attach(void) 1076 { 1077 1078 espstat_percpu = percpu_alloc(sizeof(uint64_t) * ESP_NSTATS); 1079 1080 #define MAXIV(xform) \ 1081 if (xform.ivsize > esp_max_ivlen) \ 1082 esp_max_ivlen = xform.ivsize \ 1083 1084 esp_max_ivlen = 0; 1085 MAXIV(enc_xform_des); /* SADB_EALG_DESCBC */ 1086 MAXIV(enc_xform_3des); /* SADB_EALG_3DESCBC */ 1087 MAXIV(enc_xform_rijndael128); /* SADB_X_EALG_AES */ 1088 MAXIV(enc_xform_blf); /* SADB_X_EALG_BLOWFISHCBC */ 1089 MAXIV(enc_xform_cast5); /* SADB_X_EALG_CAST128CBC */ 1090 MAXIV(enc_xform_skipjack); /* SADB_X_EALG_SKIPJACK */ 1091 MAXIV(enc_xform_camellia); /* SADB_X_EALG_CAMELLIACBC */ 1092 MAXIV(enc_xform_aes_ctr); /* SADB_X_EALG_AESCTR */ 1093 MAXIV(enc_xform_null); /* SADB_EALG_NULL */ 1094 1095 xform_register(&esp_xformsw); 1096 #undef MAXIV 1097 } 1098 #ifdef __FreeBSD__ 1099 SYSINIT(esp_xform_init, SI_SUB_DRIVERS, SI_ORDER_FIRST, esp_attach, NULL) 1100 #else 1101 #endif 1102