1 /* $NetBSD: xform_esp.c,v 1.34 2011/05/06 21:48:46 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 1.34 2011/05/06 21:48:46 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_EALG_NULL: 134 return &enc_xform_null; 135 } 136 return NULL; 137 } 138 139 size_t 140 esp_hdrsiz(const struct secasvar *sav) 141 { 142 size_t size; 143 144 if (sav != NULL) { 145 /*XXX not right for null algorithm--does it matter??*/ 146 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 147 ("esp_hdrsiz: SA with null xform")); 148 if (sav->flags & SADB_X_EXT_OLD) 149 size = sizeof (struct esp); 150 else 151 size = sizeof (struct newesp); 152 size += sav->tdb_encalgxform->blocksize + 9; 153 /*XXX need alg check???*/ 154 if (sav->tdb_authalgxform != NULL && sav->replay) 155 size += ah_hdrsiz(sav); 156 } else { 157 /* 158 * base header size 159 * + max iv length for CBC mode 160 * + max pad length 161 * + sizeof (pad length field) 162 * + sizeof (next header field) 163 * + max icv supported. 164 */ 165 size = sizeof (struct newesp) + esp_max_ivlen + 9 + 16; 166 } 167 return size; 168 } 169 170 /* 171 * esp_init() is called when an SPI is being set up. 172 */ 173 static int 174 esp_init(struct secasvar *sav, const struct xformsw *xsp) 175 { 176 const struct enc_xform *txform; 177 struct cryptoini cria, crie; 178 int keylen; 179 int error; 180 181 txform = esp_algorithm_lookup(sav->alg_enc); 182 if (txform == NULL) { 183 DPRINTF(("esp_init: unsupported encryption algorithm %d\n", 184 sav->alg_enc)); 185 return EINVAL; 186 } 187 if (sav->key_enc == NULL) { 188 DPRINTF(("esp_init: no encoding key for %s algorithm\n", 189 txform->name)); 190 return EINVAL; 191 } 192 if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) { 193 DPRINTF(("esp_init: 4-byte IV not supported with protocol\n")); 194 return EINVAL; 195 } 196 keylen = _KEYLEN(sav->key_enc); 197 if (txform->minkey > keylen || keylen > txform->maxkey) { 198 DPRINTF(("esp_init: invalid key length %u, must be in " 199 "the range [%u..%u] for algorithm %s\n", 200 keylen, txform->minkey, txform->maxkey, 201 txform->name)); 202 return EINVAL; 203 } 204 205 /* 206 * NB: The null xform needs a non-zero blocksize to keep the 207 * crypto code happy but if we use it to set ivlen then 208 * the ESP header will be processed incorrectly. The 209 * compromise is to force it to zero here. 210 */ 211 sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize); 212 sav->iv = malloc(sav->ivlen, M_SECA, M_WAITOK); 213 if (sav->iv == NULL) { 214 DPRINTF(("esp_init: no memory for IV\n")); 215 return EINVAL; 216 } 217 key_randomfill(sav->iv, sav->ivlen); /*XXX*/ 218 219 /* 220 * Setup AH-related state. 221 */ 222 if (sav->alg_auth != 0) { 223 error = ah_init0(sav, xsp, &cria); 224 if (error) 225 return error; 226 } 227 228 /* NB: override anything set in ah_init0 */ 229 sav->tdb_xform = xsp; 230 sav->tdb_encalgxform = txform; 231 232 /* Initialize crypto session. */ 233 memset(&crie, 0, sizeof (crie)); 234 crie.cri_alg = sav->tdb_encalgxform->type; 235 crie.cri_klen = _KEYBITS(sav->key_enc); 236 crie.cri_key = _KEYBUF(sav->key_enc); 237 /* XXX Rounds ? */ 238 239 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 240 /* init both auth & enc */ 241 crie.cri_next = &cria; 242 error = crypto_newsession(&sav->tdb_cryptoid, 243 &crie, crypto_support); 244 } else if (sav->tdb_encalgxform) { 245 error = crypto_newsession(&sav->tdb_cryptoid, 246 &crie, crypto_support); 247 } else if (sav->tdb_authalgxform) { 248 error = crypto_newsession(&sav->tdb_cryptoid, 249 &cria, crypto_support); 250 } else { 251 /* XXX cannot happen? */ 252 DPRINTF(("esp_init: no encoding OR authentication xform!\n")); 253 error = EINVAL; 254 } 255 return error; 256 } 257 258 /* 259 * Paranoia. 260 */ 261 static int 262 esp_zeroize(struct secasvar *sav) 263 { 264 /* NB: ah_zerorize free's the crypto session state */ 265 int error = ah_zeroize(sav); 266 267 if (sav->key_enc) 268 memset(_KEYBUF(sav->key_enc), 0, _KEYLEN(sav->key_enc)); 269 /* NB: sav->iv is freed elsewhere, even though we malloc it! */ 270 sav->tdb_encalgxform = NULL; 271 sav->tdb_xform = NULL; 272 return error; 273 } 274 275 /* 276 * ESP input processing, called (eventually) through the protocol switch. 277 */ 278 static int 279 esp_input(struct mbuf *m, const struct secasvar *sav, int skip, int protoff) 280 { 281 const struct auth_hash *esph; 282 const struct enc_xform *espx; 283 struct tdb_ident *tdbi; 284 struct tdb_crypto *tc; 285 int plen, alen, hlen; 286 struct m_tag *mtag; 287 struct newesp *esp; 288 289 struct cryptodesc *crde; 290 struct cryptop *crp; 291 292 IPSEC_SPLASSERT_SOFTNET("esp_input"); 293 294 IPSEC_ASSERT(sav != NULL, ("esp_input: null SA")); 295 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 296 ("esp_input: null encoding xform")); 297 IPSEC_ASSERT((skip&3) == 0 && (m->m_pkthdr.len&3) == 0, 298 ("esp_input: misaligned packet, skip %u pkt len %u", 299 skip, m->m_pkthdr.len)); 300 301 /* XXX don't pullup, just copy header */ 302 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 303 304 esph = sav->tdb_authalgxform; 305 espx = sav->tdb_encalgxform; 306 307 /* Determine the ESP header length */ 308 if (sav->flags & SADB_X_EXT_OLD) 309 hlen = sizeof (struct esp) + sav->ivlen; 310 else 311 hlen = sizeof (struct newesp) + sav->ivlen; 312 /* Authenticator hash size */ 313 alen = esph ? esph->authsize : 0; 314 315 /* 316 * Verify payload length is multiple of encryption algorithm 317 * block size. 318 * 319 * NB: This works for the null algorithm because the blocksize 320 * is 4 and all packets must be 4-byte aligned regardless 321 * of the algorithm. 322 */ 323 plen = m->m_pkthdr.len - (skip + hlen + alen); 324 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 325 DPRINTF(("esp_input: " 326 "payload of %d octets not a multiple of %d octets," 327 " SA %s/%08lx\n", 328 plen, espx->blocksize, 329 ipsec_address(&sav->sah->saidx.dst), 330 (u_long) ntohl(sav->spi))); 331 ESP_STATINC(ESP_STAT_BADILEN); 332 m_freem(m); 333 return EINVAL; 334 } 335 336 /* 337 * Check sequence number. 338 */ 339 if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) { 340 DPRINTF(("esp_input: packet replay check for %s\n", 341 ipsec_logsastr(sav))); /*XXX*/ 342 ESP_STATINC(ESP_STAT_REPLAY); 343 m_freem(m); 344 return ENOBUFS; /*XXX*/ 345 } 346 347 /* Update the counters */ 348 ESP_STATADD(ESP_STAT_IBYTES, m->m_pkthdr.len - skip - hlen - alen); 349 350 /* Find out if we've already done crypto */ 351 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL); 352 mtag != NULL; 353 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) { 354 tdbi = (struct tdb_ident *) (mtag + 1); 355 if (tdbi->proto == sav->sah->saidx.proto && 356 tdbi->spi == sav->spi && 357 !memcmp(&tdbi->dst, &sav->sah->saidx.dst, 358 sizeof(union sockaddr_union))) 359 break; 360 } 361 362 /* Get crypto descriptors */ 363 crp = crypto_getreq(esph && espx ? 2 : 1); 364 if (crp == NULL) { 365 DPRINTF(("esp_input: failed to acquire crypto descriptors\n")); 366 ESP_STATINC(ESP_STAT_CRYPTO); 367 m_freem(m); 368 return ENOBUFS; 369 } 370 371 /* Get IPsec-specific opaque pointer */ 372 if (esph == NULL || mtag != NULL) 373 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 374 M_XDATA, M_NOWAIT|M_ZERO); 375 else 376 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen, 377 M_XDATA, M_NOWAIT|M_ZERO); 378 if (tc == NULL) { 379 crypto_freereq(crp); 380 DPRINTF(("esp_input: failed to allocate tdb_crypto\n")); 381 ESP_STATINC(ESP_STAT_CRYPTO); 382 m_freem(m); 383 return ENOBUFS; 384 } 385 386 tc->tc_ptr = mtag; 387 388 if (esph) { 389 struct cryptodesc *crda = crp->crp_desc; 390 391 IPSEC_ASSERT(crda != NULL, ("esp_input: null ah crypto descriptor")); 392 393 /* Authentication descriptor */ 394 crda->crd_skip = skip; 395 crda->crd_len = m->m_pkthdr.len - (skip + alen); 396 crda->crd_inject = m->m_pkthdr.len - alen; 397 398 crda->crd_alg = esph->type; 399 crda->crd_key = _KEYBUF(sav->key_auth); 400 crda->crd_klen = _KEYBITS(sav->key_auth); 401 402 /* Copy the authenticator */ 403 if (mtag == NULL) 404 m_copydata(m, m->m_pkthdr.len - alen, alen, 405 (tc + 1)); 406 407 /* Chain authentication request */ 408 crde = crda->crd_next; 409 } else { 410 crde = crp->crp_desc; 411 } 412 413 /* Crypto operation descriptor */ 414 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 415 crp->crp_flags = CRYPTO_F_IMBUF; 416 crp->crp_buf = m; 417 crp->crp_callback = esp_input_cb; 418 crp->crp_sid = sav->tdb_cryptoid; 419 crp->crp_opaque = tc; 420 421 /* These are passed as-is to the callback */ 422 tc->tc_spi = sav->spi; 423 tc->tc_dst = sav->sah->saidx.dst; 424 tc->tc_proto = sav->sah->saidx.proto; 425 tc->tc_protoff = protoff; 426 tc->tc_skip = skip; 427 428 /* Decryption descriptor */ 429 if (espx) { 430 IPSEC_ASSERT(crde != NULL, ("esp_input: null esp crypto descriptor")); 431 crde->crd_skip = skip + hlen; 432 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 433 crde->crd_inject = skip + hlen - sav->ivlen; 434 435 crde->crd_alg = espx->type; 436 crde->crd_key = _KEYBUF(sav->key_enc); 437 crde->crd_klen = _KEYBITS(sav->key_enc); 438 /* XXX Rounds ? */ 439 } 440 441 if (mtag == NULL) 442 return crypto_dispatch(crp); 443 else 444 return esp_input_cb(crp); 445 } 446 447 #ifdef INET6 448 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \ 449 if (saidx->dst.sa.sa_family == AF_INET6) { \ 450 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \ 451 } else { \ 452 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \ 453 } \ 454 } while (0) 455 #else 456 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \ 457 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag)) 458 #endif 459 460 /* 461 * ESP input callback from the crypto driver. 462 */ 463 static int 464 esp_input_cb(struct cryptop *crp) 465 { 466 u_int8_t lastthree[3], aalg[AH_ALEN_MAX]; 467 int s, hlen, skip, protoff, error; 468 struct mbuf *m; 469 struct cryptodesc *crd; 470 const struct auth_hash *esph; 471 const struct enc_xform *espx; 472 struct tdb_crypto *tc; 473 struct m_tag *mtag; 474 struct secasvar *sav; 475 struct secasindex *saidx; 476 void *ptr; 477 u_int16_t dport = 0; 478 u_int16_t sport = 0; 479 #ifdef IPSEC_NAT_T 480 struct m_tag * tag = NULL; 481 #endif 482 483 crd = crp->crp_desc; 484 IPSEC_ASSERT(crd != NULL, ("esp_input_cb: null crypto descriptor!")); 485 486 tc = (struct tdb_crypto *) crp->crp_opaque; 487 IPSEC_ASSERT(tc != NULL, ("esp_input_cb: null opaque crypto data area!")); 488 skip = tc->tc_skip; 489 protoff = tc->tc_protoff; 490 mtag = (struct m_tag *) tc->tc_ptr; 491 m = (struct mbuf *) crp->crp_buf; 492 493 #ifdef IPSEC_NAT_T 494 /* find the source port for NAT-T */ 495 if ((tag = m_tag_find(m, PACKET_TAG_IPSEC_NAT_T_PORTS, NULL))) { 496 sport = ((u_int16_t *)(tag + 1))[0]; 497 dport = ((u_int16_t *)(tag + 1))[1]; 498 } 499 #endif 500 501 s = splsoftnet(); 502 mutex_enter(softnet_lock); 503 504 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi, sport, dport); 505 if (sav == NULL) { 506 ESP_STATINC(ESP_STAT_NOTDB); 507 DPRINTF(("esp_input_cb: SA expired while in crypto " 508 "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst), 509 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 510 error = ENOBUFS; /*XXX*/ 511 goto bad; 512 } 513 514 saidx = &sav->sah->saidx; 515 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 516 saidx->dst.sa.sa_family == AF_INET6, 517 ("esp_input_cb: unexpected protocol family %u", 518 saidx->dst.sa.sa_family)); 519 520 esph = sav->tdb_authalgxform; 521 espx = sav->tdb_encalgxform; 522 523 /* Check for crypto errors */ 524 if (crp->crp_etype) { 525 /* Reset the session ID */ 526 if (sav->tdb_cryptoid != 0) 527 sav->tdb_cryptoid = crp->crp_sid; 528 529 if (crp->crp_etype == EAGAIN) { 530 KEY_FREESAV(&sav); 531 mutex_exit(softnet_lock); 532 splx(s); 533 return crypto_dispatch(crp); 534 } 535 536 ESP_STATINC(ESP_STAT_NOXFORM); 537 DPRINTF(("esp_input_cb: crypto error %d\n", crp->crp_etype)); 538 error = crp->crp_etype; 539 goto bad; 540 } 541 542 /* Shouldn't happen... */ 543 if (m == NULL) { 544 ESP_STATINC(ESP_STAT_CRYPTO); 545 DPRINTF(("esp_input_cb: bogus returned buffer from crypto\n")); 546 error = EINVAL; 547 goto bad; 548 } 549 ESP_STATINC(ESP_STAT_HIST + sav->alg_enc); 550 551 /* If authentication was performed, check now. */ 552 if (esph != NULL) { 553 /* 554 * If we have a tag, it means an IPsec-aware NIC did 555 * the verification for us. Otherwise we need to 556 * check the authentication calculation. 557 */ 558 AH_STATINC(AH_STAT_HIST + sav->alg_auth); 559 if (mtag == NULL) { 560 /* Copy the authenticator from the packet */ 561 m_copydata(m, m->m_pkthdr.len - esph->authsize, 562 esph->authsize, aalg); 563 564 ptr = (tc + 1); 565 566 /* Verify authenticator */ 567 if (memcmp(ptr, aalg, esph->authsize) != 0) { 568 DPRINTF(("esp_input_cb: " 569 "authentication hash mismatch for packet in SA %s/%08lx\n", 570 ipsec_address(&saidx->dst), 571 (u_long) ntohl(sav->spi))); 572 ESP_STATINC(ESP_STAT_BADAUTH); 573 error = EACCES; 574 goto bad; 575 } 576 } 577 578 /* Remove trailing authenticator */ 579 m_adj(m, -(esph->authsize)); 580 } 581 582 /* Release the crypto descriptors */ 583 free(tc, M_XDATA), tc = NULL; 584 crypto_freereq(crp), crp = NULL; 585 586 /* 587 * Packet is now decrypted. 588 */ 589 m->m_flags |= M_DECRYPTED; 590 591 /* 592 * Update replay sequence number, if appropriate. 593 */ 594 if (sav->replay) { 595 u_int32_t seq; 596 597 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 598 sizeof (seq), &seq); 599 if (ipsec_updatereplay(ntohl(seq), sav)) { 600 DPRINTF(("%s: packet replay check for %s\n", __func__, 601 ipsec_logsastr(sav))); 602 ESP_STATINC(ESP_STAT_REPLAY); 603 error = ENOBUFS; 604 goto bad; 605 } 606 } 607 608 /* Determine the ESP header length */ 609 if (sav->flags & SADB_X_EXT_OLD) 610 hlen = sizeof (struct esp) + sav->ivlen; 611 else 612 hlen = sizeof (struct newesp) + sav->ivlen; 613 614 /* Remove the ESP header and IV from the mbuf. */ 615 error = m_striphdr(m, skip, hlen); 616 if (error) { 617 ESP_STATINC(ESP_STAT_HDROPS); 618 DPRINTF(("esp_input_cb: bad mbuf chain, SA %s/%08lx\n", 619 ipsec_address(&sav->sah->saidx.dst), 620 (u_long) ntohl(sav->spi))); 621 goto bad; 622 } 623 624 /* Save the last three bytes of decrypted data */ 625 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 626 627 /* Verify pad length */ 628 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 629 ESP_STATINC(ESP_STAT_BADILEN); 630 DPRINTF(("esp_input_cb: invalid padding length %d " 631 "for %u byte packet in SA %s/%08lx\n", 632 lastthree[1], m->m_pkthdr.len - skip, 633 ipsec_address(&sav->sah->saidx.dst), 634 (u_long) ntohl(sav->spi))); 635 error = EINVAL; 636 goto bad; 637 } 638 639 /* Verify correct decryption by checking the last padding bytes */ 640 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 641 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 642 ESP_STATINC(ESP_STAT_BADENC); 643 DPRINTF(("esp_input_cb: decryption failed " 644 "for packet in SA %s/%08lx\n", 645 ipsec_address(&sav->sah->saidx.dst), 646 (u_long) ntohl(sav->spi))); 647 DPRINTF(("esp_input_cb: %x %x\n", lastthree[0], lastthree[1])); 648 error = EINVAL; 649 goto bad; 650 } 651 } 652 653 /* Trim the mbuf chain to remove trailing authenticator and padding */ 654 m_adj(m, -(lastthree[1] + 2)); 655 656 /* Restore the Next Protocol field */ 657 m = m_copyback_cow(m, protoff, sizeof (u_int8_t), lastthree + 2, 658 M_DONTWAIT); 659 660 if (m == NULL) { 661 ESP_STATINC(ESP_STAT_CRYPTO); 662 DPRINTF(("esp_input_cb: failed to allocate mbuf\n")); 663 error = ENOBUFS; 664 goto bad; 665 } 666 667 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag); 668 669 KEY_FREESAV(&sav); 670 mutex_exit(softnet_lock); 671 splx(s); 672 return error; 673 bad: 674 if (sav) 675 KEY_FREESAV(&sav); 676 mutex_exit(softnet_lock); 677 splx(s); 678 if (m != NULL) 679 m_freem(m); 680 if (tc != NULL) 681 free(tc, M_XDATA); 682 if (crp != NULL) 683 crypto_freereq(crp); 684 return error; 685 } 686 687 /* 688 * ESP output routine, called by ipsec[46]_process_packet(). 689 */ 690 static int 691 esp_output( 692 struct mbuf *m, 693 struct ipsecrequest *isr, 694 struct mbuf **mp, 695 int skip, 696 int protoff 697 ) 698 { 699 const struct enc_xform *espx; 700 const struct auth_hash *esph; 701 int hlen, rlen, plen, padding, blks, alen, i, roff; 702 struct mbuf *mo = (struct mbuf *) NULL; 703 struct tdb_crypto *tc; 704 const struct secasvar *sav; 705 struct secasindex *saidx; 706 unsigned char *pad; 707 u_int8_t prot; 708 int error, maxpacketsize; 709 710 struct cryptodesc *crde = NULL, *crda = NULL; 711 struct cryptop *crp; 712 713 IPSEC_SPLASSERT_SOFTNET("esp_output"); 714 715 sav = isr->sav; 716 IPSEC_ASSERT(sav != NULL, ("esp_output: null SA")); 717 esph = sav->tdb_authalgxform; 718 espx = sav->tdb_encalgxform; 719 IPSEC_ASSERT(espx != NULL, ("esp_output: null encoding xform")); 720 721 if (sav->flags & SADB_X_EXT_OLD) 722 hlen = sizeof (struct esp) + sav->ivlen; 723 else 724 hlen = sizeof (struct newesp) + sav->ivlen; 725 726 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 727 /* 728 * NB: The null encoding transform has a blocksize of 4 729 * so that headers are properly aligned. 730 */ 731 blks = espx->blocksize; /* IV blocksize */ 732 733 /* XXX clamp padding length a la KAME??? */ 734 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 735 plen = rlen + padding; /* Padded payload length. */ 736 737 if (esph) 738 alen = esph->authsize; 739 else 740 alen = 0; 741 742 ESP_STATINC(ESP_STAT_OUTPUT); 743 744 saidx = &sav->sah->saidx; 745 /* Check for maximum packet size violations. */ 746 switch (saidx->dst.sa.sa_family) { 747 #ifdef INET 748 case AF_INET: 749 maxpacketsize = IP_MAXPACKET; 750 break; 751 #endif /* INET */ 752 #ifdef INET6 753 case AF_INET6: 754 maxpacketsize = IPV6_MAXPACKET; 755 break; 756 #endif /* INET6 */ 757 default: 758 DPRINTF(("esp_output: unknown/unsupported protocol " 759 "family %d, SA %s/%08lx\n", 760 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst), 761 (u_long) ntohl(sav->spi))); 762 ESP_STATINC(ESP_STAT_NOPF); 763 error = EPFNOSUPPORT; 764 goto bad; 765 } 766 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 767 DPRINTF(("esp_output: packet in SA %s/%08lx got too big " 768 "(len %u, max len %u)\n", 769 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi), 770 skip + hlen + rlen + padding + alen, maxpacketsize)); 771 ESP_STATINC(ESP_STAT_TOOBIG); 772 error = EMSGSIZE; 773 goto bad; 774 } 775 776 /* Update the counters. */ 777 ESP_STATADD(ESP_STAT_OBYTES, m->m_pkthdr.len - skip); 778 779 m = m_clone(m); 780 if (m == NULL) { 781 DPRINTF(("esp_output: cannot clone mbuf chain, SA %s/%08lx\n", 782 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 783 ESP_STATINC(ESP_STAT_HDROPS); 784 error = ENOBUFS; 785 goto bad; 786 } 787 788 /* Inject ESP header. */ 789 mo = m_makespace(m, skip, hlen, &roff); 790 if (mo == NULL) { 791 DPRINTF(("esp_output: failed to inject %u byte ESP hdr for SA " 792 "%s/%08lx\n", 793 hlen, ipsec_address(&saidx->dst), 794 (u_long) ntohl(sav->spi))); 795 ESP_STATINC(ESP_STAT_HDROPS); /* XXX diffs from openbsd */ 796 error = ENOBUFS; 797 goto bad; 798 } 799 800 /* Initialize ESP header. */ 801 memcpy(mtod(mo, char *) + roff, &sav->spi, sizeof(u_int32_t)); 802 if (sav->replay) { 803 u_int32_t replay; 804 805 #ifdef IPSEC_DEBUG 806 /* Emulate replay attack when ipsec_replay is TRUE. */ 807 if (!ipsec_replay) 808 #endif 809 sav->replay->count++; 810 811 replay = htonl(sav->replay->count); 812 bcopy(&replay, 813 mtod(mo,char *) + roff + sizeof(u_int32_t), 814 sizeof(u_int32_t)); 815 } 816 817 /* 818 * Add padding -- better to do it ourselves than use the crypto engine, 819 * although if/when we support compression, we'd have to do that. 820 */ 821 pad = (u_char *) m_pad(m, padding + alen); 822 if (pad == NULL) { 823 DPRINTF(("esp_output: m_pad failed for SA %s/%08lx\n", 824 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 825 m = NULL; /* NB: free'd by m_pad */ 826 error = ENOBUFS; 827 goto bad; 828 } 829 830 /* 831 * Add padding: random, zero, or self-describing. 832 * XXX catch unexpected setting 833 */ 834 switch (sav->flags & SADB_X_EXT_PMASK) { 835 case SADB_X_EXT_PRAND: 836 (void) read_random(pad, padding - 2); 837 break; 838 case SADB_X_EXT_PZERO: 839 memset(pad, 0, padding - 2); 840 break; 841 case SADB_X_EXT_PSEQ: 842 for (i = 0; i < padding - 2; i++) 843 pad[i] = i+1; 844 break; 845 } 846 847 /* Fix padding length and Next Protocol in padding itself. */ 848 pad[padding - 2] = padding - 2; 849 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 850 851 /* Fix Next Protocol in IPv4/IPv6 header. */ 852 prot = IPPROTO_ESP; 853 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 854 855 /* Get crypto descriptors. */ 856 crp = crypto_getreq(esph && espx ? 2 : 1); 857 if (crp == NULL) { 858 DPRINTF(("esp_output: failed to acquire crypto descriptors\n")); 859 ESP_STATINC(ESP_STAT_CRYPTO); 860 error = ENOBUFS; 861 goto bad; 862 } 863 864 if (espx) { 865 crde = crp->crp_desc; 866 crda = crde->crd_next; 867 868 /* Encryption descriptor. */ 869 crde->crd_skip = skip + hlen; 870 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 871 crde->crd_flags = CRD_F_ENCRYPT; 872 crde->crd_inject = skip + hlen - sav->ivlen; 873 874 /* Encryption operation. */ 875 crde->crd_alg = espx->type; 876 crde->crd_key = _KEYBUF(sav->key_enc); 877 crde->crd_klen = _KEYBITS(sav->key_enc); 878 /* XXX Rounds ? */ 879 } else 880 crda = crp->crp_desc; 881 882 /* IPsec-specific opaque crypto info. */ 883 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 884 M_XDATA, M_NOWAIT|M_ZERO); 885 if (tc == NULL) { 886 crypto_freereq(crp); 887 DPRINTF(("esp_output: failed to allocate tdb_crypto\n")); 888 ESP_STATINC(ESP_STAT_CRYPTO); 889 error = ENOBUFS; 890 goto bad; 891 } 892 893 /* Callback parameters */ 894 tc->tc_isr = isr; 895 tc->tc_spi = sav->spi; 896 tc->tc_dst = saidx->dst; 897 tc->tc_proto = saidx->proto; 898 899 /* Crypto operation descriptor. */ 900 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 901 crp->crp_flags = CRYPTO_F_IMBUF; 902 crp->crp_buf = m; 903 crp->crp_callback = esp_output_cb; 904 crp->crp_opaque = tc; 905 crp->crp_sid = sav->tdb_cryptoid; 906 907 if (esph) { 908 /* Authentication descriptor. */ 909 crda->crd_skip = skip; 910 crda->crd_len = m->m_pkthdr.len - (skip + alen); 911 crda->crd_inject = m->m_pkthdr.len - alen; 912 913 /* Authentication operation. */ 914 crda->crd_alg = esph->type; 915 crda->crd_key = _KEYBUF(sav->key_auth); 916 crda->crd_klen = _KEYBITS(sav->key_auth); 917 } 918 919 return crypto_dispatch(crp); 920 bad: 921 if (m) 922 m_freem(m); 923 return (error); 924 } 925 926 /* 927 * ESP output callback from the crypto driver. 928 */ 929 static int 930 esp_output_cb(struct cryptop *crp) 931 { 932 struct tdb_crypto *tc; 933 struct ipsecrequest *isr; 934 struct secasvar *sav; 935 struct mbuf *m; 936 int s, err, error; 937 938 tc = (struct tdb_crypto *) crp->crp_opaque; 939 IPSEC_ASSERT(tc != NULL, ("esp_output_cb: null opaque data area!")); 940 m = (struct mbuf *) crp->crp_buf; 941 942 s = splsoftnet(); 943 mutex_enter(softnet_lock); 944 945 isr = tc->tc_isr; 946 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi, 0, 0); 947 if (sav == NULL) { 948 ESP_STATINC(ESP_STAT_NOTDB); 949 DPRINTF(("esp_output_cb: SA expired while in crypto " 950 "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst), 951 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 952 error = ENOBUFS; /*XXX*/ 953 goto bad; 954 } 955 IPSEC_ASSERT(isr->sav == sav, 956 ("esp_output_cb: SA changed was %p now %p\n", isr->sav, sav)); 957 958 /* Check for crypto errors. */ 959 if (crp->crp_etype) { 960 /* Reset session ID. */ 961 if (sav->tdb_cryptoid != 0) 962 sav->tdb_cryptoid = crp->crp_sid; 963 964 if (crp->crp_etype == EAGAIN) { 965 KEY_FREESAV(&sav); 966 mutex_exit(softnet_lock); 967 splx(s); 968 return crypto_dispatch(crp); 969 } 970 971 ESP_STATINC(ESP_STAT_NOXFORM); 972 DPRINTF(("esp_output_cb: crypto error %d\n", crp->crp_etype)); 973 error = crp->crp_etype; 974 goto bad; 975 } 976 977 /* Shouldn't happen... */ 978 if (m == NULL) { 979 ESP_STATINC(ESP_STAT_CRYPTO); 980 DPRINTF(("esp_output_cb: bogus returned buffer from crypto\n")); 981 error = EINVAL; 982 goto bad; 983 } 984 ESP_STATINC(ESP_STAT_HIST + sav->alg_enc); 985 if (sav->tdb_authalgxform != NULL) 986 AH_STATINC(AH_STAT_HIST + sav->alg_auth); 987 988 /* Release crypto descriptors. */ 989 free(tc, M_XDATA); 990 crypto_freereq(crp); 991 992 #ifdef IPSEC_DEBUG 993 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 994 if (ipsec_integrity) { 995 static unsigned char ipseczeroes[AH_ALEN_MAX]; 996 const struct auth_hash *esph; 997 998 /* 999 * Corrupt HMAC if we want to test integrity verification of 1000 * the other side. 1001 */ 1002 esph = sav->tdb_authalgxform; 1003 if (esph != NULL) { 1004 m_copyback(m, m->m_pkthdr.len - esph->authsize, 1005 esph->authsize, ipseczeroes); 1006 } 1007 } 1008 #endif 1009 1010 /* NB: m is reclaimed by ipsec_process_done. */ 1011 err = ipsec_process_done(m, isr); 1012 KEY_FREESAV(&sav); 1013 mutex_exit(softnet_lock); 1014 splx(s); 1015 return err; 1016 bad: 1017 if (sav) 1018 KEY_FREESAV(&sav); 1019 mutex_exit(softnet_lock); 1020 splx(s); 1021 if (m) 1022 m_freem(m); 1023 free(tc, M_XDATA); 1024 crypto_freereq(crp); 1025 return error; 1026 } 1027 1028 static struct xformsw esp_xformsw = { 1029 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 1030 esp_init, esp_zeroize, esp_input, 1031 esp_output, 1032 NULL, 1033 }; 1034 1035 INITFN void 1036 esp_attach(void) 1037 { 1038 1039 espstat_percpu = percpu_alloc(sizeof(uint64_t) * ESP_NSTATS); 1040 1041 #define MAXIV(xform) \ 1042 if (xform.blocksize > esp_max_ivlen) \ 1043 esp_max_ivlen = xform.blocksize \ 1044 1045 esp_max_ivlen = 0; 1046 MAXIV(enc_xform_des); /* SADB_EALG_DESCBC */ 1047 MAXIV(enc_xform_3des); /* SADB_EALG_3DESCBC */ 1048 MAXIV(enc_xform_rijndael128); /* SADB_X_EALG_AES */ 1049 MAXIV(enc_xform_blf); /* SADB_X_EALG_BLOWFISHCBC */ 1050 MAXIV(enc_xform_cast5); /* SADB_X_EALG_CAST128CBC */ 1051 MAXIV(enc_xform_skipjack); /* SADB_X_EALG_SKIPJACK */ 1052 MAXIV(enc_xform_camellia); /* SADB_X_EALG_CAMELLIACBC */ 1053 MAXIV(enc_xform_null); /* SADB_EALG_NULL */ 1054 1055 xform_register(&esp_xformsw); 1056 #undef MAXIV 1057 } 1058 #ifdef __FreeBSD__ 1059 SYSINIT(esp_xform_init, SI_SUB_DRIVERS, SI_ORDER_FIRST, esp_attach, NULL) 1060 #else 1061 #endif 1062