xform_esp.c revision 169425
1/* $FreeBSD: head/sys/netipsec/xform_esp.c 169425 2007-05-09 19:37:02Z gnn $ */ 2/* $OpenBSD: ip_esp.c,v 1.69 2001/06/26 06:18:59 angelos Exp $ */ 3/*- 4 * The authors of this code are John Ioannidis (ji@tla.org), 5 * Angelos D. Keromytis (kermit@csd.uch.gr) and 6 * Niels Provos (provos@physnet.uni-hamburg.de). 7 * 8 * The original version of this code was written by John Ioannidis 9 * for BSD/OS in Athens, Greece, in November 1995. 10 * 11 * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996, 12 * by Angelos D. Keromytis. 13 * 14 * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis 15 * and Niels Provos. 16 * 17 * Additional features in 1999 by Angelos D. Keromytis. 18 * 19 * Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis, 20 * Angelos D. Keromytis and Niels Provos. 21 * Copyright (c) 2001 Angelos D. Keromytis. 22 * 23 * Permission to use, copy, and modify this software with or without fee 24 * is hereby granted, provided that this entire notice is included in 25 * all copies of any software which is or includes a copy or 26 * modification of this software. 27 * You may use this code under the GNU public license if you so wish. Please 28 * contribute changes back to the authors under this freer than GPL license 29 * so that we may further the use of strong encryption without limitations to 30 * all. 31 * 32 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR 33 * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY 34 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE 35 * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR 36 * PURPOSE. 37 */ 38#include "opt_inet.h" 39#include "opt_inet6.h" 40 41#include <sys/param.h> 42#include <sys/systm.h> 43#include <sys/mbuf.h> 44#include <sys/socket.h> 45#include <sys/syslog.h> 46#include <sys/kernel.h> 47#include <sys/random.h> 48#include <sys/sysctl.h> 49 50#include <net/if.h> 51 52#include <netinet/in.h> 53#include <netinet/in_systm.h> 54#include <netinet/ip.h> 55#include <netinet/ip_ecn.h> 56#include <netinet/ip6.h> 57 58#include <net/route.h> 59#include <netipsec/ipsec.h> 60#include <netipsec/ah.h> 61#include <netipsec/ah_var.h> 62#include <netipsec/esp.h> 63#include <netipsec/esp_var.h> 64#include <netipsec/xform.h> 65 66#ifdef INET6 67#include <netinet6/ip6_var.h> 68#include <netipsec/ipsec6.h> 69#include <netinet6/ip6_ecn.h> 70#endif 71 72#include <netipsec/key.h> 73#include <netipsec/key_debug.h> 74 75#include <opencrypto/cryptodev.h> 76#include <opencrypto/xform.h> 77 78int esp_enable = 1; 79struct espstat espstat; 80 81SYSCTL_DECL(_net_inet_esp); 82SYSCTL_INT(_net_inet_esp, OID_AUTO, 83 esp_enable, CTLFLAG_RW, &esp_enable, 0, ""); 84SYSCTL_STRUCT(_net_inet_esp, IPSECCTL_STATS, 85 stats, CTLFLAG_RD, &espstat, espstat, ""); 86 87static int esp_max_ivlen; /* max iv length over all algorithms */ 88 89static int esp_input_cb(struct cryptop *op); 90static int esp_output_cb(struct cryptop *crp); 91 92/* 93 * NB: this is public for use by the PF_KEY support. 94 * NB: if you add support here; be sure to add code to esp_attach below! 95 */ 96struct enc_xform * 97esp_algorithm_lookup(int alg) 98{ 99 if (alg >= ESP_ALG_MAX) 100 return NULL; 101 switch (alg) { 102 case SADB_EALG_DESCBC: 103 return &enc_xform_des; 104 case SADB_EALG_3DESCBC: 105 return &enc_xform_3des; 106 case SADB_X_EALG_AES: 107 return &enc_xform_rijndael128; 108 case SADB_X_EALG_BLOWFISHCBC: 109 return &enc_xform_blf; 110 case SADB_X_EALG_CAST128CBC: 111 return &enc_xform_cast5; 112 case SADB_X_EALG_SKIPJACK: 113 return &enc_xform_skipjack; 114 case SADB_EALG_NULL: 115 return &enc_xform_null; 116 case SADB_X_EALG_CAMELLIACBC: 117 return &enc_xform_camellia; 118 } 119 return NULL; 120} 121 122size_t 123esp_hdrsiz(struct secasvar *sav) 124{ 125 size_t size; 126 127 if (sav != NULL) { 128 /*XXX not right for null algorithm--does it matter??*/ 129 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 130 ("SA with null xform")); 131 if (sav->flags & SADB_X_EXT_OLD) 132 size = sizeof (struct esp); 133 else 134 size = sizeof (struct newesp); 135 size += sav->tdb_encalgxform->blocksize + 9; 136 /*XXX need alg check???*/ 137 if (sav->tdb_authalgxform != NULL && sav->replay) 138 size += ah_hdrsiz(sav); 139 } else { 140 /* 141 * base header size 142 * + max iv length for CBC mode 143 * + max pad length 144 * + sizeof (pad length field) 145 * + sizeof (next header field) 146 * + max icv supported. 147 */ 148 size = sizeof (struct newesp) + esp_max_ivlen + 9 + 16; 149 } 150 return size; 151} 152 153/* 154 * esp_init() is called when an SPI is being set up. 155 */ 156static int 157esp_init(struct secasvar *sav, struct xformsw *xsp) 158{ 159 struct enc_xform *txform; 160 struct cryptoini cria, crie; 161 int keylen; 162 int error; 163 164 txform = esp_algorithm_lookup(sav->alg_enc); 165 if (txform == NULL) { 166 DPRINTF(("%s: unsupported encryption algorithm %d\n", 167 __func__, sav->alg_enc)); 168 return EINVAL; 169 } 170 if (sav->key_enc == NULL) { 171 DPRINTF(("%s: no encoding key for %s algorithm\n", 172 __func__, txform->name)); 173 return EINVAL; 174 } 175 if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) { 176 DPRINTF(("%s: 4-byte IV not supported with protocol\n", 177 __func__)); 178 return EINVAL; 179 } 180 keylen = _KEYLEN(sav->key_enc); 181 if (txform->minkey > keylen || keylen > txform->maxkey) { 182 DPRINTF(("%s: invalid key length %u, must be in the range " 183 "[%u..%u] for algorithm %s\n", __func__, 184 keylen, txform->minkey, txform->maxkey, 185 txform->name)); 186 return EINVAL; 187 } 188 189 /* 190 * NB: The null xform needs a non-zero blocksize to keep the 191 * crypto code happy but if we use it to set ivlen then 192 * the ESP header will be processed incorrectly. The 193 * compromise is to force it to zero here. 194 */ 195 sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize); 196 sav->iv = (caddr_t) malloc(sav->ivlen, M_XDATA, M_WAITOK); 197 if (sav->iv == NULL) { 198 DPRINTF(("%s: no memory for IV\n", __func__)); 199 return EINVAL; 200 } 201 key_randomfill(sav->iv, sav->ivlen); /*XXX*/ 202 203 /* 204 * Setup AH-related state. 205 */ 206 if (sav->alg_auth != 0) { 207 error = ah_init0(sav, xsp, &cria); 208 if (error) 209 return error; 210 } 211 212 /* NB: override anything set in ah_init0 */ 213 sav->tdb_xform = xsp; 214 sav->tdb_encalgxform = txform; 215 216 /* Initialize crypto session. */ 217 bzero(&crie, sizeof (crie)); 218 crie.cri_alg = sav->tdb_encalgxform->type; 219 crie.cri_klen = _KEYBITS(sav->key_enc); 220 crie.cri_key = sav->key_enc->key_data; 221 /* XXX Rounds ? */ 222 223 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 224 /* init both auth & enc */ 225 crie.cri_next = &cria; 226 error = crypto_newsession(&sav->tdb_cryptoid, 227 &crie, crypto_support); 228 } else if (sav->tdb_encalgxform) { 229 error = crypto_newsession(&sav->tdb_cryptoid, 230 &crie, crypto_support); 231 } else if (sav->tdb_authalgxform) { 232 error = crypto_newsession(&sav->tdb_cryptoid, 233 &cria, crypto_support); 234 } else { 235 /* XXX cannot happen? */ 236 DPRINTF(("%s: no encoding OR authentication xform!\n", 237 __func__)); 238 error = EINVAL; 239 } 240 return error; 241} 242 243/* 244 * Paranoia. 245 */ 246static int 247esp_zeroize(struct secasvar *sav) 248{ 249 /* NB: ah_zerorize free's the crypto session state */ 250 int error = ah_zeroize(sav); 251 252 if (sav->key_enc) 253 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc)); 254 if (sav->iv) { 255 free(sav->iv, M_XDATA); 256 sav->iv = NULL; 257 } 258 sav->tdb_encalgxform = NULL; 259 sav->tdb_xform = NULL; 260 return error; 261} 262 263/* 264 * ESP input processing, called (eventually) through the protocol switch. 265 */ 266static int 267esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 268{ 269 struct auth_hash *esph; 270 struct enc_xform *espx; 271 struct tdb_ident *tdbi; 272 struct tdb_crypto *tc; 273 int plen, alen, hlen; 274 struct m_tag *mtag; 275 struct newesp *esp; 276 277 struct cryptodesc *crde; 278 struct cryptop *crp; 279 280 IPSEC_SPLASSERT_SOFTNET(__func__); 281 282 IPSEC_ASSERT(sav != NULL, ("null SA")); 283 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); 284 IPSEC_ASSERT((skip&3) == 0 && (m->m_pkthdr.len&3) == 0, 285 ("misaligned packet, skip %u pkt len %u", 286 skip, m->m_pkthdr.len)); 287 288 /* XXX don't pullup, just copy header */ 289 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 290 291 esph = sav->tdb_authalgxform; 292 espx = sav->tdb_encalgxform; 293 294 /* Determine the ESP header length */ 295 if (sav->flags & SADB_X_EXT_OLD) 296 hlen = sizeof (struct esp) + sav->ivlen; 297 else 298 hlen = sizeof (struct newesp) + sav->ivlen; 299 /* Authenticator hash size */ 300 alen = esph ? AH_HMAC_HASHLEN : 0; 301 302 /* 303 * Verify payload length is multiple of encryption algorithm 304 * block size. 305 * 306 * NB: This works for the null algorithm because the blocksize 307 * is 4 and all packets must be 4-byte aligned regardless 308 * of the algorithm. 309 */ 310 plen = m->m_pkthdr.len - (skip + hlen + alen); 311 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 312 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 313 " SA %s/%08lx\n", __func__, 314 plen, espx->blocksize, 315 ipsec_address(&sav->sah->saidx.dst), 316 (u_long) ntohl(sav->spi))); 317 espstat.esps_badilen++; 318 m_freem(m); 319 return EINVAL; 320 } 321 322 /* 323 * Check sequence number. 324 */ 325 if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) { 326 DPRINTF(("%s: packet replay check for %s\n", __func__, 327 ipsec_logsastr(sav))); /*XXX*/ 328 espstat.esps_replay++; 329 m_freem(m); 330 return ENOBUFS; /*XXX*/ 331 } 332 333 /* Update the counters */ 334 espstat.esps_ibytes += m->m_pkthdr.len - (skip + hlen + alen); 335 336 /* Find out if we've already done crypto */ 337 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL); 338 mtag != NULL; 339 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) { 340 tdbi = (struct tdb_ident *) (mtag + 1); 341 if (tdbi->proto == sav->sah->saidx.proto && 342 tdbi->spi == sav->spi && 343 !bcmp(&tdbi->dst, &sav->sah->saidx.dst, 344 sizeof(union sockaddr_union))) 345 break; 346 } 347 348 /* Get crypto descriptors */ 349 crp = crypto_getreq(esph && espx ? 2 : 1); 350 if (crp == NULL) { 351 DPRINTF(("%s: failed to acquire crypto descriptors\n", 352 __func__)); 353 espstat.esps_crypto++; 354 m_freem(m); 355 return ENOBUFS; 356 } 357 358 /* Get IPsec-specific opaque pointer */ 359 if (esph == NULL || mtag != NULL) 360 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 361 M_XDATA, M_NOWAIT|M_ZERO); 362 else 363 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen, 364 M_XDATA, M_NOWAIT|M_ZERO); 365 if (tc == NULL) { 366 crypto_freereq(crp); 367 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 368 espstat.esps_crypto++; 369 m_freem(m); 370 return ENOBUFS; 371 } 372 373 tc->tc_ptr = (caddr_t) mtag; 374 375 if (esph) { 376 struct cryptodesc *crda = crp->crp_desc; 377 378 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor")); 379 380 /* Authentication descriptor */ 381 crda->crd_skip = skip; 382 crda->crd_len = m->m_pkthdr.len - (skip + alen); 383 crda->crd_inject = m->m_pkthdr.len - alen; 384 385 crda->crd_alg = esph->type; 386 crda->crd_key = sav->key_auth->key_data; 387 crda->crd_klen = _KEYBITS(sav->key_auth); 388 389 /* Copy the authenticator */ 390 if (mtag == NULL) 391 m_copydata(m, m->m_pkthdr.len - alen, alen, 392 (caddr_t) (tc + 1)); 393 394 /* Chain authentication request */ 395 crde = crda->crd_next; 396 } else { 397 crde = crp->crp_desc; 398 } 399 400 /* Crypto operation descriptor */ 401 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 402 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 403 crp->crp_buf = (caddr_t) m; 404 crp->crp_callback = esp_input_cb; 405 crp->crp_sid = sav->tdb_cryptoid; 406 crp->crp_opaque = (caddr_t) tc; 407 408 /* These are passed as-is to the callback */ 409 tc->tc_spi = sav->spi; 410 tc->tc_dst = sav->sah->saidx.dst; 411 tc->tc_proto = sav->sah->saidx.proto; 412 tc->tc_protoff = protoff; 413 tc->tc_skip = skip; 414 415 /* Decryption descriptor */ 416 if (espx) { 417 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor")); 418 crde->crd_skip = skip + hlen; 419 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 420 crde->crd_inject = skip + hlen - sav->ivlen; 421 422 crde->crd_alg = espx->type; 423 crde->crd_key = sav->key_enc->key_data; 424 crde->crd_klen = _KEYBITS(sav->key_enc); 425 /* XXX Rounds ? */ 426 } 427 428 if (mtag == NULL) 429 return crypto_dispatch(crp); 430 else 431 return esp_input_cb(crp); 432} 433 434#ifdef INET6 435#define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \ 436 if (saidx->dst.sa.sa_family == AF_INET6) { \ 437 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \ 438 } else { \ 439 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \ 440 } \ 441} while (0) 442#else 443#define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \ 444 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag)) 445#endif 446 447/* 448 * ESP input callback from the crypto driver. 449 */ 450static int 451esp_input_cb(struct cryptop *crp) 452{ 453 u_int8_t lastthree[3], aalg[AH_HMAC_HASHLEN]; 454 int hlen, skip, protoff, error; 455 struct mbuf *m; 456 struct cryptodesc *crd; 457 struct auth_hash *esph; 458 struct enc_xform *espx; 459 struct tdb_crypto *tc; 460 struct m_tag *mtag; 461 struct secasvar *sav; 462 struct secasindex *saidx; 463 caddr_t ptr; 464 465 NET_LOCK_GIANT(); 466 467 crd = crp->crp_desc; 468 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!")); 469 470 tc = (struct tdb_crypto *) crp->crp_opaque; 471 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!")); 472 skip = tc->tc_skip; 473 protoff = tc->tc_protoff; 474 mtag = (struct m_tag *) tc->tc_ptr; 475 m = (struct mbuf *) crp->crp_buf; 476 477 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 478 if (sav == NULL) { 479 espstat.esps_notdb++; 480 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 481 __func__, ipsec_address(&tc->tc_dst), 482 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 483 error = ENOBUFS; /*XXX*/ 484 goto bad; 485 } 486 487 saidx = &sav->sah->saidx; 488 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 489 saidx->dst.sa.sa_family == AF_INET6, 490 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 491 492 esph = sav->tdb_authalgxform; 493 espx = sav->tdb_encalgxform; 494 495 /* Check for crypto errors */ 496 if (crp->crp_etype) { 497 /* Reset the session ID */ 498 if (sav->tdb_cryptoid != 0) 499 sav->tdb_cryptoid = crp->crp_sid; 500 501 if (crp->crp_etype == EAGAIN) { 502 KEY_FREESAV(&sav); 503 error = crypto_dispatch(crp); 504 NET_UNLOCK_GIANT(); 505 return error; 506 } 507 508 espstat.esps_noxform++; 509 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 510 error = crp->crp_etype; 511 goto bad; 512 } 513 514 /* Shouldn't happen... */ 515 if (m == NULL) { 516 espstat.esps_crypto++; 517 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 518 error = EINVAL; 519 goto bad; 520 } 521 espstat.esps_hist[sav->alg_enc]++; 522 523 /* If authentication was performed, check now. */ 524 if (esph != NULL) { 525 /* 526 * If we have a tag, it means an IPsec-aware NIC did 527 * the verification for us. Otherwise we need to 528 * check the authentication calculation. 529 */ 530 ahstat.ahs_hist[sav->alg_auth]++; 531 if (mtag == NULL) { 532 /* Copy the authenticator from the packet */ 533 m_copydata(m, m->m_pkthdr.len - AH_HMAC_HASHLEN, 534 AH_HMAC_HASHLEN, aalg); 535 536 ptr = (caddr_t) (tc + 1); 537 538 /* Verify authenticator */ 539 if (bcmp(ptr, aalg, AH_HMAC_HASHLEN) != 0) { 540 DPRINTF(("%s: " 541 "authentication hash mismatch for packet in SA %s/%08lx\n", 542 __func__, 543 ipsec_address(&saidx->dst), 544 (u_long) ntohl(sav->spi))); 545 espstat.esps_badauth++; 546 error = EACCES; 547 goto bad; 548 } 549 } 550 551 /* Remove trailing authenticator */ 552 m_adj(m, -AH_HMAC_HASHLEN); 553 } 554 555 /* Release the crypto descriptors */ 556 free(tc, M_XDATA), tc = NULL; 557 crypto_freereq(crp), crp = NULL; 558 559 /* 560 * Packet is now decrypted. 561 */ 562 m->m_flags |= M_DECRYPTED; 563 564 /* 565 * Update replay sequence number, if appropriate. 566 */ 567 if (sav->replay) { 568 u_int32_t seq; 569 570 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 571 sizeof (seq), (caddr_t) &seq); 572 if (ipsec_updatereplay(ntohl(seq), sav)) { 573 DPRINTF(("%s: packet replay check for %s\n", __func__, 574 ipsec_logsastr(sav))); 575 espstat.esps_replay++; 576 error = ENOBUFS; 577 goto bad; 578 } 579 } 580 581 /* Determine the ESP header length */ 582 if (sav->flags & SADB_X_EXT_OLD) 583 hlen = sizeof (struct esp) + sav->ivlen; 584 else 585 hlen = sizeof (struct newesp) + sav->ivlen; 586 587 /* Remove the ESP header and IV from the mbuf. */ 588 error = m_striphdr(m, skip, hlen); 589 if (error) { 590 espstat.esps_hdrops++; 591 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 592 ipsec_address(&sav->sah->saidx.dst), 593 (u_long) ntohl(sav->spi))); 594 goto bad; 595 } 596 597 /* Save the last three bytes of decrypted data */ 598 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 599 600 /* Verify pad length */ 601 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 602 espstat.esps_badilen++; 603 DPRINTF(("%s: invalid padding length %d for %u byte packet " 604 "in SA %s/%08lx\n", __func__, 605 lastthree[1], m->m_pkthdr.len - skip, 606 ipsec_address(&sav->sah->saidx.dst), 607 (u_long) ntohl(sav->spi))); 608 error = EINVAL; 609 goto bad; 610 } 611 612 /* Verify correct decryption by checking the last padding bytes */ 613 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 614 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 615 espstat.esps_badenc++; 616 DPRINTF(("%s: decryption failed for packet in " 617 "SA %s/%08lx\n", __func__, 618 ipsec_address(&sav->sah->saidx.dst), 619 (u_long) ntohl(sav->spi))); 620 error = EINVAL; 621 goto bad; 622 } 623 } 624 625 /* Trim the mbuf chain to remove trailing authenticator and padding */ 626 m_adj(m, -(lastthree[1] + 2)); 627 628 /* Restore the Next Protocol field */ 629 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 630 631 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag); 632 633 KEY_FREESAV(&sav); 634 NET_UNLOCK_GIANT(); 635 return error; 636bad: 637 if (sav) 638 KEY_FREESAV(&sav); 639 if (m != NULL) 640 m_freem(m); 641 if (tc != NULL) 642 free(tc, M_XDATA); 643 if (crp != NULL) 644 crypto_freereq(crp); 645 NET_UNLOCK_GIANT(); 646 return error; 647} 648 649/* 650 * ESP output routine, called by ipsec[46]_process_packet(). 651 */ 652static int 653esp_output( 654 struct mbuf *m, 655 struct ipsecrequest *isr, 656 struct mbuf **mp, 657 int skip, 658 int protoff 659) 660{ 661 struct enc_xform *espx; 662 struct auth_hash *esph; 663 int hlen, rlen, plen, padding, blks, alen, i, roff; 664 struct mbuf *mo = (struct mbuf *) NULL; 665 struct tdb_crypto *tc; 666 struct secasvar *sav; 667 struct secasindex *saidx; 668 unsigned char *pad; 669 u_int8_t prot; 670 int error, maxpacketsize; 671 672 struct cryptodesc *crde = NULL, *crda = NULL; 673 struct cryptop *crp; 674 675 IPSEC_SPLASSERT_SOFTNET(__func__); 676 677 sav = isr->sav; 678 IPSEC_ASSERT(sav != NULL, ("null SA")); 679 esph = sav->tdb_authalgxform; 680 espx = sav->tdb_encalgxform; 681 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 682 683 if (sav->flags & SADB_X_EXT_OLD) 684 hlen = sizeof (struct esp) + sav->ivlen; 685 else 686 hlen = sizeof (struct newesp) + sav->ivlen; 687 688 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 689 /* 690 * NB: The null encoding transform has a blocksize of 4 691 * so that headers are properly aligned. 692 */ 693 blks = espx->blocksize; /* IV blocksize */ 694 695 /* XXX clamp padding length a la KAME??? */ 696 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 697 plen = rlen + padding; /* Padded payload length. */ 698 699 if (esph) 700 alen = AH_HMAC_HASHLEN; 701 else 702 alen = 0; 703 704 espstat.esps_output++; 705 706 saidx = &sav->sah->saidx; 707 /* Check for maximum packet size violations. */ 708 switch (saidx->dst.sa.sa_family) { 709#ifdef INET 710 case AF_INET: 711 maxpacketsize = IP_MAXPACKET; 712 break; 713#endif /* INET */ 714#ifdef INET6 715 case AF_INET6: 716 maxpacketsize = IPV6_MAXPACKET; 717 break; 718#endif /* INET6 */ 719 default: 720 DPRINTF(("%s: unknown/unsupported protocol " 721 "family %d, SA %s/%08lx\n", __func__, 722 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst), 723 (u_long) ntohl(sav->spi))); 724 espstat.esps_nopf++; 725 error = EPFNOSUPPORT; 726 goto bad; 727 } 728 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 729 DPRINTF(("%s: packet in SA %s/%08lx got too big " 730 "(len %u, max len %u)\n", __func__, 731 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi), 732 skip + hlen + rlen + padding + alen, maxpacketsize)); 733 espstat.esps_toobig++; 734 error = EMSGSIZE; 735 goto bad; 736 } 737 738 /* Update the counters. */ 739 espstat.esps_obytes += m->m_pkthdr.len - skip; 740 741 m = m_unshare(m, M_NOWAIT); 742 if (m == NULL) { 743 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 744 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 745 espstat.esps_hdrops++; 746 error = ENOBUFS; 747 goto bad; 748 } 749 750 /* Inject ESP header. */ 751 mo = m_makespace(m, skip, hlen, &roff); 752 if (mo == NULL) { 753 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 754 __func__, hlen, ipsec_address(&saidx->dst), 755 (u_long) ntohl(sav->spi))); 756 espstat.esps_hdrops++; /* XXX diffs from openbsd */ 757 error = ENOBUFS; 758 goto bad; 759 } 760 761 /* Initialize ESP header. */ 762 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t)); 763 if (sav->replay) { 764 u_int32_t replay; 765 766#ifdef REGRESSION 767 /* Emulate replay attack when ipsec_replay is TRUE. */ 768 if (!ipsec_replay) 769#endif 770 sav->replay->count++; 771 replay = htonl(sav->replay->count); 772 bcopy((caddr_t) &replay, 773 mtod(mo, caddr_t) + roff + sizeof(u_int32_t), 774 sizeof(u_int32_t)); 775 } 776 777 /* 778 * Add padding -- better to do it ourselves than use the crypto engine, 779 * although if/when we support compression, we'd have to do that. 780 */ 781 pad = (u_char *) m_pad(m, padding + alen); 782 if (pad == NULL) { 783 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 784 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 785 m = NULL; /* NB: free'd by m_pad */ 786 error = ENOBUFS; 787 goto bad; 788 } 789 790 /* 791 * Add padding: random, zero, or self-describing. 792 * XXX catch unexpected setting 793 */ 794 switch (sav->flags & SADB_X_EXT_PMASK) { 795 case SADB_X_EXT_PRAND: 796 (void) read_random(pad, padding - 2); 797 break; 798 case SADB_X_EXT_PZERO: 799 bzero(pad, padding - 2); 800 break; 801 case SADB_X_EXT_PSEQ: 802 for (i = 0; i < padding - 2; i++) 803 pad[i] = i+1; 804 break; 805 } 806 807 /* Fix padding length and Next Protocol in padding itself. */ 808 pad[padding - 2] = padding - 2; 809 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 810 811 /* Fix Next Protocol in IPv4/IPv6 header. */ 812 prot = IPPROTO_ESP; 813 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 814 815 /* Get crypto descriptors. */ 816 crp = crypto_getreq(esph && espx ? 2 : 1); 817 if (crp == NULL) { 818 DPRINTF(("%s: failed to acquire crypto descriptors\n", 819 __func__)); 820 espstat.esps_crypto++; 821 error = ENOBUFS; 822 goto bad; 823 } 824 825 if (espx) { 826 crde = crp->crp_desc; 827 crda = crde->crd_next; 828 829 /* Encryption descriptor. */ 830 crde->crd_skip = skip + hlen; 831 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 832 crde->crd_flags = CRD_F_ENCRYPT; 833 crde->crd_inject = skip + hlen - sav->ivlen; 834 835 /* Encryption operation. */ 836 crde->crd_alg = espx->type; 837 crde->crd_key = sav->key_enc->key_data; 838 crde->crd_klen = _KEYBITS(sav->key_enc); 839 /* XXX Rounds ? */ 840 } else 841 crda = crp->crp_desc; 842 843 /* IPsec-specific opaque crypto info. */ 844 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 845 M_XDATA, M_NOWAIT|M_ZERO); 846 if (tc == NULL) { 847 crypto_freereq(crp); 848 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 849 espstat.esps_crypto++; 850 error = ENOBUFS; 851 goto bad; 852 } 853 854 /* Callback parameters */ 855 tc->tc_isr = isr; 856 tc->tc_spi = sav->spi; 857 tc->tc_dst = saidx->dst; 858 tc->tc_proto = saidx->proto; 859 860 /* Crypto operation descriptor. */ 861 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 862 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 863 crp->crp_buf = (caddr_t) m; 864 crp->crp_callback = esp_output_cb; 865 crp->crp_opaque = (caddr_t) tc; 866 crp->crp_sid = sav->tdb_cryptoid; 867 868 if (esph) { 869 /* Authentication descriptor. */ 870 crda->crd_skip = skip; 871 crda->crd_len = m->m_pkthdr.len - (skip + alen); 872 crda->crd_inject = m->m_pkthdr.len - alen; 873 874 /* Authentication operation. */ 875 crda->crd_alg = esph->type; 876 crda->crd_key = sav->key_auth->key_data; 877 crda->crd_klen = _KEYBITS(sav->key_auth); 878 } 879 880 return crypto_dispatch(crp); 881bad: 882 if (m) 883 m_freem(m); 884 return (error); 885} 886 887/* 888 * ESP output callback from the crypto driver. 889 */ 890static int 891esp_output_cb(struct cryptop *crp) 892{ 893 struct tdb_crypto *tc; 894 struct ipsecrequest *isr; 895 struct secasvar *sav; 896 struct mbuf *m; 897 int err, error; 898 899 NET_LOCK_GIANT(); 900 901 tc = (struct tdb_crypto *) crp->crp_opaque; 902 IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); 903 m = (struct mbuf *) crp->crp_buf; 904 905 isr = tc->tc_isr; 906 IPSECREQUEST_LOCK(isr); 907 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 908 if (sav == NULL) { 909 espstat.esps_notdb++; 910 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 911 __func__, ipsec_address(&tc->tc_dst), 912 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 913 error = ENOBUFS; /*XXX*/ 914 goto bad; 915 } 916 IPSEC_ASSERT(isr->sav == sav, 917 ("SA changed was %p now %p\n", isr->sav, sav)); 918 919 /* Check for crypto errors. */ 920 if (crp->crp_etype) { 921 /* Reset session ID. */ 922 if (sav->tdb_cryptoid != 0) 923 sav->tdb_cryptoid = crp->crp_sid; 924 925 if (crp->crp_etype == EAGAIN) { 926 KEY_FREESAV(&sav); 927 IPSECREQUEST_UNLOCK(isr); 928 error = crypto_dispatch(crp); 929 NET_UNLOCK_GIANT(); 930 return error; 931 } 932 933 espstat.esps_noxform++; 934 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 935 error = crp->crp_etype; 936 goto bad; 937 } 938 939 /* Shouldn't happen... */ 940 if (m == NULL) { 941 espstat.esps_crypto++; 942 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 943 error = EINVAL; 944 goto bad; 945 } 946 espstat.esps_hist[sav->alg_enc]++; 947 if (sav->tdb_authalgxform != NULL) 948 ahstat.ahs_hist[sav->alg_auth]++; 949 950 /* Release crypto descriptors. */ 951 free(tc, M_XDATA); 952 crypto_freereq(crp); 953 954#ifdef REGRESSION 955 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 956 if (ipsec_integrity) { 957 static unsigned char ipseczeroes[AH_HMAC_HASHLEN]; 958 struct auth_hash *esph; 959 960 /* 961 * Corrupt HMAC if we want to test integrity verification of 962 * the other side. 963 */ 964 esph = sav->tdb_authalgxform; 965 if (esph != NULL) { 966 m_copyback(m, m->m_pkthdr.len - AH_HMAC_HASHLEN, 967 AH_HMAC_HASHLEN, ipseczeroes); 968 } 969 } 970#endif 971 972 /* NB: m is reclaimed by ipsec_process_done. */ 973 err = ipsec_process_done(m, isr); 974 KEY_FREESAV(&sav); 975 IPSECREQUEST_UNLOCK(isr); 976 NET_UNLOCK_GIANT(); 977 return err; 978bad: 979 if (sav) 980 KEY_FREESAV(&sav); 981 IPSECREQUEST_UNLOCK(isr); 982 if (m) 983 m_freem(m); 984 free(tc, M_XDATA); 985 crypto_freereq(crp); 986 NET_UNLOCK_GIANT(); 987 return error; 988} 989 990static struct xformsw esp_xformsw = { 991 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 992 esp_init, esp_zeroize, esp_input, 993 esp_output 994}; 995 996static void 997esp_attach(void) 998{ 999#define MAXIV(xform) \ 1000 if (xform.blocksize > esp_max_ivlen) \ 1001 esp_max_ivlen = xform.blocksize \ 1002 1003 esp_max_ivlen = 0; 1004 MAXIV(enc_xform_des); /* SADB_EALG_DESCBC */ 1005 MAXIV(enc_xform_3des); /* SADB_EALG_3DESCBC */ 1006 MAXIV(enc_xform_rijndael128); /* SADB_X_EALG_AES */ 1007 MAXIV(enc_xform_blf); /* SADB_X_EALG_BLOWFISHCBC */ 1008 MAXIV(enc_xform_cast5); /* SADB_X_EALG_CAST128CBC */ 1009 MAXIV(enc_xform_skipjack); /* SADB_X_EALG_SKIPJACK */ 1010 MAXIV(enc_xform_null); /* SADB_EALG_NULL */ 1011 MAXIV(enc_xform_camellia); /* SADB_X_EALG_CAMELLIACBC */ 1012 1013 xform_register(&esp_xformsw); 1014#undef MAXIV 1015} 1016SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL); 1017