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sys/netipsec/xform_esp.c
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1 /* $NetBSD: xform_esp.c,v 1.12 2006/11/16 01:33:49 christos 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 1.12 2006/11/16 01:33:49 christos 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 58 #include <net/if.h> 59 60 #include <netinet/in.h> 61 #include <netinet/in_systm.h> 62 #include <netinet/ip.h> 63 #include <netinet/ip_ecn.h> 64 #include <netinet/ip6.h> 65 66 #include <net/route.h> 67 #include <netipsec/ipsec.h> 68 #include <netipsec/ah.h> 69 #include <netipsec/ah_var.h> 70 #include <netipsec/esp.h> 71 #include <netipsec/esp_var.h> 72 #include <netipsec/xform.h> 73 74 #ifdef INET6 75 #include <netinet6/ip6_var.h> 76 #include <netipsec/ipsec6.h> 77 # ifdef __FreeBSD__ 78 # include <netinet6/ip6_ecn.h> 79 # endif 80 #endif 81 82 #include <netipsec/key.h> 83 #include <netipsec/key_debug.h> 84 85 #include <netipsec/ipsec_osdep.h> 86 87 #include <opencrypto/cryptodev.h> 88 #include <opencrypto/xform.h> 89 90 int esp_enable = 1; 91 struct espstat espstat; 92 93 #ifdef __FreeBSD__ 94 SYSCTL_DECL(_net_inet_esp); 95 SYSCTL_INT(_net_inet_esp, OID_AUTO, 96 esp_enable, CTLFLAG_RW, &esp_enable, 0, ""); 97 SYSCTL_STRUCT(_net_inet_esp, IPSECCTL_STATS, 98 stats, CTLFLAG_RD, &espstat, espstat, ""); 99 #endif /* __FreeBSD__ */ 100 101 static int esp_max_ivlen; /* max iv length over all algorithms */ 102 103 static int esp_input_cb(struct cryptop *op); 104 static int esp_output_cb(struct cryptop *crp); 105 106 /* 107 * NB: this is public for use by the PF_KEY support. 108 * NB: if you add support here; be sure to add code to esp_attach below! 109 */ 110 struct enc_xform * 111 esp_algorithm_lookup(int alg) 112 { 113 if (alg >= ESP_ALG_MAX) 114 return NULL; 115 switch (alg) { 116 case SADB_EALG_DESCBC: 117 return &enc_xform_des; 118 case SADB_EALG_3DESCBC: 119 return &enc_xform_3des; 120 case SADB_X_EALG_AES: 121 return &enc_xform_rijndael128; 122 case SADB_X_EALG_BLOWFISHCBC: 123 return &enc_xform_blf; 124 case SADB_X_EALG_CAST128CBC: 125 return &enc_xform_cast5; 126 case SADB_X_EALG_SKIPJACK: 127 return &enc_xform_skipjack; 128 case SADB_EALG_NULL: 129 return &enc_xform_null; 130 } 131 return NULL; 132 } 133 134 size_t 135 esp_hdrsiz(struct secasvar *sav) 136 { 137 size_t size; 138 139 if (sav != NULL) { 140 /*XXX not right for null algorithm--does it matter??*/ 141 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 142 ("esp_hdrsiz: SA with null xform")); 143 if (sav->flags & SADB_X_EXT_OLD) 144 size = sizeof (struct esp); 145 else 146 size = sizeof (struct newesp); 147 size += sav->tdb_encalgxform->blocksize + 9; 148 /*XXX need alg check???*/ 149 if (sav->tdb_authalgxform != NULL && sav->replay) 150 size += ah_hdrsiz(sav); 151 } else { 152 /* 153 * base header size 154 * + max iv length for CBC mode 155 * + max pad length 156 * + sizeof (pad length field) 157 * + sizeof (next header field) 158 * + max icv supported. 159 */ 160 size = sizeof (struct newesp) + esp_max_ivlen + 9 + 16; 161 } 162 return size; 163 } 164 165 /* 166 * esp_init() is called when an SPI is being set up. 167 */ 168 static int 169 esp_init(struct secasvar *sav, struct xformsw *xsp) 170 { 171 struct enc_xform *txform; 172 struct cryptoini cria, crie; 173 int keylen; 174 int error; 175 176 txform = esp_algorithm_lookup(sav->alg_enc); 177 if (txform == NULL) { 178 DPRINTF(("esp_init: unsupported encryption algorithm %d\n", 179 sav->alg_enc)); 180 return EINVAL; 181 } 182 if (sav->key_enc == NULL) { 183 DPRINTF(("esp_init: no encoding key for %s algorithm\n", 184 txform->name)); 185 return EINVAL; 186 } 187 if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) { 188 DPRINTF(("esp_init: 4-byte IV not supported with protocol\n")); 189 return EINVAL; 190 } 191 keylen = _KEYLEN(sav->key_enc); 192 if (txform->minkey > keylen || keylen > txform->maxkey) { 193 DPRINTF(("esp_init: invalid key length %u, must be in " 194 "the range [%u..%u] for algorithm %s\n", 195 keylen, txform->minkey, txform->maxkey, 196 txform->name)); 197 return EINVAL; 198 } 199 200 /* 201 * NB: The null xform needs a non-zero blocksize to keep the 202 * crypto code happy but if we use it to set ivlen then 203 * the ESP header will be processed incorrectly. The 204 * compromise is to force it to zero here. 205 */ 206 sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize); 207 sav->iv = (caddr_t) malloc(sav->ivlen, M_SECA, M_WAITOK); 208 if (sav->iv == NULL) { 209 DPRINTF(("esp_init: no memory for IV\n")); 210 return EINVAL; 211 } 212 key_randomfill(sav->iv, sav->ivlen); /*XXX*/ 213 214 /* 215 * Setup AH-related state. 216 */ 217 if (sav->alg_auth != 0) { 218 error = ah_init0(sav, xsp, &cria); 219 if (error) 220 return error; 221 } 222 223 /* NB: override anything set in ah_init0 */ 224 sav->tdb_xform = xsp; 225 sav->tdb_encalgxform = txform; 226 227 /* Initialize crypto session. */ 228 bzero(&crie, sizeof (crie)); 229 crie.cri_alg = sav->tdb_encalgxform->type; 230 crie.cri_klen = _KEYBITS(sav->key_enc); 231 crie.cri_key = _KEYBUF(sav->key_enc); 232 /* XXX Rounds ? */ 233 234 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 235 /* init both auth & enc */ 236 crie.cri_next = &cria; 237 error = crypto_newsession(&sav->tdb_cryptoid, 238 &crie, crypto_support); 239 } else if (sav->tdb_encalgxform) { 240 error = crypto_newsession(&sav->tdb_cryptoid, 241 &crie, crypto_support); 242 } else if (sav->tdb_authalgxform) { 243 error = crypto_newsession(&sav->tdb_cryptoid, 244 &cria, crypto_support); 245 } else { 246 /* XXX cannot happen? */ 247 DPRINTF(("esp_init: no encoding OR authentication xform!\n")); 248 error = EINVAL; 249 } 250 return error; 251 } 252 253 /* 254 * Paranoia. 255 */ 256 static int 257 esp_zeroize(struct secasvar *sav) 258 { 259 /* NB: ah_zerorize free's the crypto session state */ 260 int error = ah_zeroize(sav); 261 262 if (sav->key_enc) 263 bzero(_KEYBUF(sav->key_enc), _KEYLEN(sav->key_enc)); 264 /* NB: sav->iv is freed elsewhere, even though we malloc it! */ 265 sav->tdb_encalgxform = NULL; 266 sav->tdb_xform = NULL; 267 return error; 268 } 269 270 /* 271 * ESP input processing, called (eventually) through the protocol switch. 272 */ 273 static int 274 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 275 { 276 struct auth_hash *esph; 277 struct enc_xform *espx; 278 struct tdb_ident *tdbi; 279 struct tdb_crypto *tc; 280 int plen, alen, hlen; 281 struct m_tag *mtag; 282 struct newesp *esp; 283 284 struct cryptodesc *crde; 285 struct cryptop *crp; 286 287 IPSEC_SPLASSERT_SOFTNET("esp_input"); 288 289 IPSEC_ASSERT(sav != NULL, ("esp_input: null SA")); 290 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 291 ("esp_input: null encoding xform")); 292 IPSEC_ASSERT((skip&3) == 0 && (m->m_pkthdr.len&3) == 0, 293 ("esp_input: misaligned packet, skip %u pkt len %u", 294 skip, m->m_pkthdr.len)); 295 296 /* XXX don't pullup, just copy header */ 297 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 298 299 esph = sav->tdb_authalgxform; 300 espx = sav->tdb_encalgxform; 301 302 /* Determine the ESP header length */ 303 if (sav->flags & SADB_X_EXT_OLD) 304 hlen = sizeof (struct esp) + sav->ivlen; 305 else 306 hlen = sizeof (struct newesp) + sav->ivlen; 307 /* Authenticator hash size */ 308 alen = esph ? AH_HMAC_HASHLEN : 0; 309 310 /* 311 * Verify payload length is multiple of encryption algorithm 312 * block size. 313 * 314 * NB: This works for the null algorithm because the blocksize 315 * is 4 and all packets must be 4-byte aligned regardless 316 * of the algorithm. 317 */ 318 plen = m->m_pkthdr.len - (skip + hlen + alen); 319 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 320 DPRINTF(("esp_input: " 321 "payload of %d octets not a multiple of %d octets," 322 " SA %s/%08lx\n", 323 plen, espx->blocksize, 324 ipsec_address(&sav->sah->saidx.dst), 325 (u_long) ntohl(sav->spi))); 326 espstat.esps_badilen++; 327 m_freem(m); 328 return EINVAL; 329 } 330 331 /* 332 * Check sequence number. 333 */ 334 if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) { 335 DPRINTF(("esp_input: packet replay check for %s\n", 336 ipsec_logsastr(sav))); /*XXX*/ 337 espstat.esps_replay++; 338 m_freem(m); 339 return ENOBUFS; /*XXX*/ 340 } 341 342 /* Update the counters */ 343 espstat.esps_ibytes += m->m_pkthdr.len - skip - hlen - alen; 344 345 /* Find out if we've already done crypto */ 346 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL); 347 mtag != NULL; 348 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) { 349 tdbi = (struct tdb_ident *) (mtag + 1); 350 if (tdbi->proto == sav->sah->saidx.proto && 351 tdbi->spi == sav->spi && 352 !bcmp(&tdbi->dst, &sav->sah->saidx.dst, 353 sizeof(union sockaddr_union))) 354 break; 355 } 356 357 /* Get crypto descriptors */ 358 crp = crypto_getreq(esph && espx ? 2 : 1); 359 if (crp == NULL) { 360 DPRINTF(("esp_input: failed to acquire crypto descriptors\n")); 361 espstat.esps_crypto++; 362 m_freem(m); 363 return ENOBUFS; 364 } 365 366 /* Get IPsec-specific opaque pointer */ 367 if (esph == NULL || mtag != NULL) 368 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 369 M_XDATA, M_NOWAIT|M_ZERO); 370 else 371 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen, 372 M_XDATA, M_NOWAIT|M_ZERO); 373 if (tc == NULL) { 374 crypto_freereq(crp); 375 DPRINTF(("esp_input: failed to allocate tdb_crypto\n")); 376 espstat.esps_crypto++; 377 m_freem(m); 378 return ENOBUFS; 379 } 380 381 tc->tc_ptr = (caddr_t) mtag; 382 383 if (esph) { 384 struct cryptodesc *crda = crp->crp_desc; 385 386 IPSEC_ASSERT(crda != NULL, ("esp_input: null ah crypto descriptor")); 387 388 /* Authentication descriptor */ 389 crda->crd_skip = skip; 390 crda->crd_len = m->m_pkthdr.len - (skip + alen); 391 crda->crd_inject = m->m_pkthdr.len - alen; 392 393 crda->crd_alg = esph->type; 394 crda->crd_key = _KEYBUF(sav->key_auth); 395 crda->crd_klen = _KEYBITS(sav->key_auth); 396 397 /* Copy the authenticator */ 398 if (mtag == NULL) 399 m_copydata(m, m->m_pkthdr.len - alen, alen, 400 (caddr_t) (tc + 1)); 401 402 /* Chain authentication request */ 403 crde = crda->crd_next; 404 } else { 405 crde = crp->crp_desc; 406 } 407 408 /* Crypto operation descriptor */ 409 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 410 crp->crp_flags = CRYPTO_F_IMBUF; 411 crp->crp_buf = (caddr_t) m; 412 crp->crp_callback = esp_input_cb; 413 crp->crp_sid = sav->tdb_cryptoid; 414 crp->crp_opaque = (caddr_t) tc; 415 416 /* These are passed as-is to the callback */ 417 tc->tc_spi = sav->spi; 418 tc->tc_dst = sav->sah->saidx.dst; 419 tc->tc_proto = sav->sah->saidx.proto; 420 tc->tc_protoff = protoff; 421 tc->tc_skip = skip; 422 423 /* Decryption descriptor */ 424 if (espx) { 425 IPSEC_ASSERT(crde != NULL, ("esp_input: null esp crypto descriptor")); 426 crde->crd_skip = skip + hlen; 427 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 428 crde->crd_inject = skip + hlen - sav->ivlen; 429 430 crde->crd_alg = espx->type; 431 crde->crd_key = _KEYBUF(sav->key_enc); 432 crde->crd_klen = _KEYBITS(sav->key_enc); 433 /* XXX Rounds ? */ 434 } 435 436 if (mtag == NULL) 437 return crypto_dispatch(crp); 438 else 439 return esp_input_cb(crp); 440 } 441 442 #ifdef INET6 443 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \ 444 if (saidx->dst.sa.sa_family == AF_INET6) { \ 445 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \ 446 } else { \ 447 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \ 448 } \ 449 } while (0) 450 #else 451 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \ 452 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag)) 453 #endif 454 455 /* 456 * ESP input callback from the crypto driver. 457 */ 458 static int 459 esp_input_cb(struct cryptop *crp) 460 { 461 u_int8_t lastthree[3], aalg[AH_HMAC_HASHLEN]; 462 int s, hlen, skip, protoff, error; 463 struct mbuf *m; 464 struct cryptodesc *crd; 465 struct auth_hash *esph; 466 struct enc_xform *espx; 467 struct tdb_crypto *tc; 468 struct m_tag *mtag; 469 struct secasvar *sav; 470 struct secasindex *saidx; 471 caddr_t ptr; 472 473 crd = crp->crp_desc; 474 IPSEC_ASSERT(crd != NULL, ("esp_input_cb: null crypto descriptor!")); 475 476 tc = (struct tdb_crypto *) crp->crp_opaque; 477 IPSEC_ASSERT(tc != NULL, ("esp_input_cb: null opaque crypto data area!")); 478 skip = tc->tc_skip; 479 protoff = tc->tc_protoff; 480 mtag = (struct m_tag *) tc->tc_ptr; 481 m = (struct mbuf *) crp->crp_buf; 482 483 s = splsoftnet(); 484 485 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 486 if (sav == NULL) { 487 espstat.esps_notdb++; 488 DPRINTF(("esp_input_cb: SA expired while in crypto " 489 "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst), 490 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 491 error = ENOBUFS; /*XXX*/ 492 goto bad; 493 } 494 495 saidx = &sav->sah->saidx; 496 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 497 saidx->dst.sa.sa_family == AF_INET6, 498 ("ah_input_cb: unexpected protocol family %u", 499 saidx->dst.sa.sa_family)); 500 501 esph = sav->tdb_authalgxform; 502 espx = sav->tdb_encalgxform; 503 504 /* Check for crypto errors */ 505 if (crp->crp_etype) { 506 /* Reset the session ID */ 507 if (sav->tdb_cryptoid != 0) 508 sav->tdb_cryptoid = crp->crp_sid; 509 510 if (crp->crp_etype == EAGAIN) { 511 KEY_FREESAV(&sav); 512 splx(s); 513 return crypto_dispatch(crp); 514 } 515 516 espstat.esps_noxform++; 517 DPRINTF(("esp_input_cb: crypto error %d\n", crp->crp_etype)); 518 error = crp->crp_etype; 519 goto bad; 520 } 521 522 /* Shouldn't happen... */ 523 if (m == NULL) { 524 espstat.esps_crypto++; 525 DPRINTF(("esp_input_cb: bogus returned buffer from crypto\n")); 526 error = EINVAL; 527 goto bad; 528 } 529 espstat.esps_hist[sav->alg_enc]++; 530 531 /* If authentication was performed, check now. */ 532 if (esph != NULL) { 533 /* 534 * If we have a tag, it means an IPsec-aware NIC did 535 * the verification for us. Otherwise we need to 536 * check the authentication calculation. 537 */ 538 ahstat.ahs_hist[sav->alg_auth]++; 539 if (mtag == NULL) { 540 /* Copy the authenticator from the packet */ 541 m_copydata(m, m->m_pkthdr.len - esph->authsize, 542 esph->authsize, aalg); 543 544 ptr = (caddr_t) (tc + 1); 545 546 /* Verify authenticator */ 547 if (bcmp(ptr, aalg, esph->authsize) != 0) { 548 DPRINTF(("esp_input_cb: " 549 "authentication hash mismatch for packet in SA %s/%08lx\n", 550 ipsec_address(&saidx->dst), 551 (u_long) ntohl(sav->spi))); 552 espstat.esps_badauth++; 553 error = EACCES; 554 goto bad; 555 } 556 } 557 558 /* Remove trailing authenticator */ 559 m_adj(m, -(esph->authsize)); 560 } 561 562 /* Release the crypto descriptors */ 563 free(tc, M_XDATA), tc = NULL; 564 crypto_freereq(crp), crp = NULL; 565 566 /* 567 * Packet is now decrypted. 568 */ 569 m->m_flags |= M_DECRYPTED; 570 571 /* 572 * Update replay sequence number, if appropriate. 573 */ 574 if (sav->replay) { 575 u_int32_t seq; 576 577 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 578 sizeof (seq), (caddr_t) &seq); 579 if (ipsec_updatereplay(ntohl(seq), sav)) { 580 DPRINTF(("%s: packet replay check for %s\n", __func__, 581 ipsec_logsastr(sav))); 582 espstat.esps_replay++; 583 error = ENOBUFS; 584 goto bad; 585 } 586 } 587 588 /* Determine the ESP header length */ 589 if (sav->flags & SADB_X_EXT_OLD) 590 hlen = sizeof (struct esp) + sav->ivlen; 591 else 592 hlen = sizeof (struct newesp) + sav->ivlen; 593 594 /* Remove the ESP header and IV from the mbuf. */ 595 error = m_striphdr(m, skip, hlen); 596 if (error) { 597 espstat.esps_hdrops++; 598 DPRINTF(("esp_input_cb: bad mbuf chain, SA %s/%08lx\n", 599 ipsec_address(&sav->sah->saidx.dst), 600 (u_long) ntohl(sav->spi))); 601 goto bad; 602 } 603 604 /* Save the last three bytes of decrypted data */ 605 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 606 607 /* Verify pad length */ 608 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 609 espstat.esps_badilen++; 610 DPRINTF(("esp_input_cb: invalid padding length %d " 611 "for %u byte packet in SA %s/%08lx\n", 612 lastthree[1], m->m_pkthdr.len - skip, 613 ipsec_address(&sav->sah->saidx.dst), 614 (u_long) ntohl(sav->spi))); 615 error = EINVAL; 616 goto bad; 617 } 618 619 /* Verify correct decryption by checking the last padding bytes */ 620 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 621 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 622 espstat.esps_badenc++; 623 DPRINTF(("esp_input_cb: decryption failed " 624 "for packet in SA %s/%08lx\n", 625 ipsec_address(&sav->sah->saidx.dst), 626 (u_long) ntohl(sav->spi))); 627 DPRINTF(("esp_input_cb: %x %x\n", lastthree[0], lastthree[1])); 628 error = EINVAL; 629 goto bad; 630 } 631 } 632 633 /* Trim the mbuf chain to remove trailing authenticator and padding */ 634 m_adj(m, -(lastthree[1] + 2)); 635 636 /* Restore the Next Protocol field */ 637 m = m_copyback_cow(m, protoff, sizeof (u_int8_t), lastthree + 2, 638 M_DONTWAIT); 639 640 if (m == NULL) { 641 espstat.esps_crypto++; 642 DPRINTF(("esp_input_cb: failed to allocate mbuf\n")); 643 error = ENOBUFS; 644 goto bad; 645 } 646 647 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag); 648 649 KEY_FREESAV(&sav); 650 splx(s); 651 return error; 652 bad: 653 if (sav) 654 KEY_FREESAV(&sav); 655 splx(s); 656 if (m != NULL) 657 m_freem(m); 658 if (tc != NULL) 659 free(tc, M_XDATA); 660 if (crp != NULL) 661 crypto_freereq(crp); 662 return error; 663 } 664 665 /* 666 * ESP output routine, called by ipsec[46]_process_packet(). 667 */ 668 static int 669 esp_output( 670 struct mbuf *m, 671 struct ipsecrequest *isr, 672 struct mbuf **mp, 673 int skip, 674 int protoff 675 ) 676 { 677 struct enc_xform *espx; 678 struct auth_hash *esph; 679 int hlen, rlen, plen, padding, blks, alen, i, roff; 680 struct mbuf *mo = (struct mbuf *) NULL; 681 struct tdb_crypto *tc; 682 struct secasvar *sav; 683 struct secasindex *saidx; 684 unsigned char *pad; 685 u_int8_t prot; 686 int error, maxpacketsize; 687 688 struct cryptodesc *crde = NULL, *crda = NULL; 689 struct cryptop *crp; 690 691 IPSEC_SPLASSERT_SOFTNET("esp_output"); 692 693 sav = isr->sav; 694 IPSEC_ASSERT(sav != NULL, ("esp_output: null SA")); 695 esph = sav->tdb_authalgxform; 696 espx = sav->tdb_encalgxform; 697 IPSEC_ASSERT(espx != NULL, ("esp_output: null encoding xform")); 698 699 if (sav->flags & SADB_X_EXT_OLD) 700 hlen = sizeof (struct esp) + sav->ivlen; 701 else 702 hlen = sizeof (struct newesp) + sav->ivlen; 703 704 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 705 /* 706 * NB: The null encoding transform has a blocksize of 4 707 * so that headers are properly aligned. 708 */ 709 blks = espx->blocksize; /* IV blocksize */ 710 711 /* XXX clamp padding length a la KAME??? */ 712 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 713 plen = rlen + padding; /* Padded payload length. */ 714 715 if (esph) 716 alen = AH_HMAC_HASHLEN; 717 else 718 alen = 0; 719 720 espstat.esps_output++; 721 722 saidx = &sav->sah->saidx; 723 /* Check for maximum packet size violations. */ 724 switch (saidx->dst.sa.sa_family) { 725 #ifdef INET 726 case AF_INET: 727 maxpacketsize = IP_MAXPACKET; 728 break; 729 #endif /* INET */ 730 #ifdef INET6 731 case AF_INET6: 732 maxpacketsize = IPV6_MAXPACKET; 733 break; 734 #endif /* INET6 */ 735 default: 736 DPRINTF(("esp_output: unknown/unsupported protocol " 737 "family %d, SA %s/%08lx\n", 738 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst), 739 (u_long) ntohl(sav->spi))); 740 espstat.esps_nopf++; 741 error = EPFNOSUPPORT; 742 goto bad; 743 } 744 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 745 DPRINTF(("esp_output: packet in SA %s/%08lx got too big " 746 "(len %u, max len %u)\n", 747 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi), 748 skip + hlen + rlen + padding + alen, maxpacketsize)); 749 espstat.esps_toobig++; 750 error = EMSGSIZE; 751 goto bad; 752 } 753 754 /* Update the counters. */ 755 espstat.esps_obytes += m->m_pkthdr.len - skip; 756 757 m = m_clone(m); 758 if (m == NULL) { 759 DPRINTF(("esp_output: cannot clone mbuf chain, SA %s/%08lx\n", 760 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 761 espstat.esps_hdrops++; 762 error = ENOBUFS; 763 goto bad; 764 } 765 766 /* Inject ESP header. */ 767 mo = m_makespace(m, skip, hlen, &roff); 768 if (mo == NULL) { 769 DPRINTF(("esp_output: failed to inject %u byte ESP hdr for SA " 770 "%s/%08lx\n", 771 hlen, ipsec_address(&saidx->dst), 772 (u_long) ntohl(sav->spi))); 773 espstat.esps_hdrops++; /* XXX diffs from openbsd */ 774 error = ENOBUFS; 775 goto bad; 776 } 777 778 /* Initialize ESP header. */ 779 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t)); 780 if (sav->replay) { 781 u_int32_t replay; 782 783 #ifdef IPSEC_DEBUG 784 /* Emulate replay attack when ipsec_replay is TRUE. */ 785 if (!ipsec_replay) 786 #endif 787 sav->replay->count++; 788 789 replay = htonl(sav->replay->count); 790 bcopy((caddr_t) &replay, 791 mtod(mo, caddr_t) + roff + sizeof(u_int32_t), 792 sizeof(u_int32_t)); 793 } 794 795 /* 796 * Add padding -- better to do it ourselves than use the crypto engine, 797 * although if/when we support compression, we'd have to do that. 798 */ 799 pad = (u_char *) m_pad(m, padding + alen); 800 if (pad == NULL) { 801 DPRINTF(("esp_output: m_pad failed for SA %s/%08lx\n", 802 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 803 m = NULL; /* NB: free'd by m_pad */ 804 error = ENOBUFS; 805 goto bad; 806 } 807 808 /* 809 * Add padding: random, zero, or self-describing. 810 * XXX catch unexpected setting 811 */ 812 switch (sav->flags & SADB_X_EXT_PMASK) { 813 case SADB_X_EXT_PRAND: 814 (void) read_random(pad, padding - 2); 815 break; 816 case SADB_X_EXT_PZERO: 817 bzero(pad, padding - 2); 818 break; 819 case SADB_X_EXT_PSEQ: 820 for (i = 0; i < padding - 2; i++) 821 pad[i] = i+1; 822 break; 823 } 824 825 /* Fix padding length and Next Protocol in padding itself. */ 826 pad[padding - 2] = padding - 2; 827 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 828 829 /* Fix Next Protocol in IPv4/IPv6 header. */ 830 prot = IPPROTO_ESP; 831 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 832 833 /* Get crypto descriptors. */ 834 crp = crypto_getreq(esph && espx ? 2 : 1); 835 if (crp == NULL) { 836 DPRINTF(("esp_output: failed to acquire crypto descriptors\n")); 837 espstat.esps_crypto++; 838 error = ENOBUFS; 839 goto bad; 840 } 841 842 if (espx) { 843 crde = crp->crp_desc; 844 crda = crde->crd_next; 845 846 /* Encryption descriptor. */ 847 crde->crd_skip = skip + hlen; 848 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 849 crde->crd_flags = CRD_F_ENCRYPT; 850 crde->crd_inject = skip + hlen - sav->ivlen; 851 852 /* Encryption operation. */ 853 crde->crd_alg = espx->type; 854 crde->crd_key = _KEYBUF(sav->key_enc); 855 crde->crd_klen = _KEYBITS(sav->key_enc); 856 /* XXX Rounds ? */ 857 } else 858 crda = crp->crp_desc; 859 860 /* IPsec-specific opaque crypto info. */ 861 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 862 M_XDATA, M_NOWAIT|M_ZERO); 863 if (tc == NULL) { 864 crypto_freereq(crp); 865 DPRINTF(("esp_output: failed to allocate tdb_crypto\n")); 866 espstat.esps_crypto++; 867 error = ENOBUFS; 868 goto bad; 869 } 870 871 /* Callback parameters */ 872 tc->tc_isr = isr; 873 tc->tc_spi = sav->spi; 874 tc->tc_dst = saidx->dst; 875 tc->tc_proto = saidx->proto; 876 877 /* Crypto operation descriptor. */ 878 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 879 crp->crp_flags = CRYPTO_F_IMBUF; 880 crp->crp_buf = (caddr_t) m; 881 crp->crp_callback = esp_output_cb; 882 crp->crp_opaque = (caddr_t) tc; 883 crp->crp_sid = sav->tdb_cryptoid; 884 885 if (esph) { 886 /* Authentication descriptor. */ 887 crda->crd_skip = skip; 888 crda->crd_len = m->m_pkthdr.len - (skip + alen); 889 crda->crd_inject = m->m_pkthdr.len - alen; 890 891 /* Authentication operation. */ 892 crda->crd_alg = esph->type; 893 crda->crd_key = _KEYBUF(sav->key_auth); 894 crda->crd_klen = _KEYBITS(sav->key_auth); 895 } 896 897 return crypto_dispatch(crp); 898 bad: 899 if (m) 900 m_freem(m); 901 return (error); 902 } 903 904 /* 905 * ESP output callback from the crypto driver. 906 */ 907 static int 908 esp_output_cb(struct cryptop *crp) 909 { 910 struct tdb_crypto *tc; 911 struct ipsecrequest *isr; 912 struct secasvar *sav; 913 struct mbuf *m; 914 int s, err, error; 915 916 tc = (struct tdb_crypto *) crp->crp_opaque; 917 IPSEC_ASSERT(tc != NULL, ("esp_output_cb: null opaque data area!")); 918 m = (struct mbuf *) crp->crp_buf; 919 920 s = splsoftnet(); 921 922 isr = tc->tc_isr; 923 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 924 if (sav == NULL) { 925 espstat.esps_notdb++; 926 DPRINTF(("esp_output_cb: SA expired while in crypto " 927 "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst), 928 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 929 error = ENOBUFS; /*XXX*/ 930 goto bad; 931 } 932 IPSEC_ASSERT(isr->sav == sav, 933 ("esp_output_cb: SA changed was %p now %p\n", isr->sav, sav)); 934 935 /* Check for crypto errors. */ 936 if (crp->crp_etype) { 937 /* Reset session ID. */ 938 if (sav->tdb_cryptoid != 0) 939 sav->tdb_cryptoid = crp->crp_sid; 940 941 if (crp->crp_etype == EAGAIN) { 942 KEY_FREESAV(&sav); 943 splx(s); 944 return crypto_dispatch(crp); 945 } 946 947 espstat.esps_noxform++; 948 DPRINTF(("esp_output_cb: crypto error %d\n", crp->crp_etype)); 949 error = crp->crp_etype; 950 goto bad; 951 } 952 953 /* Shouldn't happen... */ 954 if (m == NULL) { 955 espstat.esps_crypto++; 956 DPRINTF(("esp_output_cb: bogus returned buffer from crypto\n")); 957 error = EINVAL; 958 goto bad; 959 } 960 espstat.esps_hist[sav->alg_enc]++; 961 if (sav->tdb_authalgxform != NULL) 962 ahstat.ahs_hist[sav->alg_auth]++; 963 964 /* Release crypto descriptors. */ 965 free(tc, M_XDATA); 966 crypto_freereq(crp); 967 968 #ifdef IPSEC_DEBUG 969 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 970 if (ipsec_integrity) { 971 static unsigned char ipseczeroes[AH_HMAC_HASHLEN]; 972 struct auth_hash *esph; 973 974 /* 975 * Corrupt HMAC if we want to test integrity verification of 976 * the other side. 977 */ 978 esph = sav->tdb_authalgxform; 979 if (esph != NULL) { 980 m_copyback(m, m->m_pkthdr.len - AH_HMAC_HASHLEN, 981 AH_HMAC_HASHLEN, ipseczeroes); 982 } 983 } 984 #endif 985 986 /* NB: m is reclaimed by ipsec_process_done. */ 987 err = ipsec_process_done(m, isr); 988 KEY_FREESAV(&sav); 989 splx(s); 990 return err; 991 bad: 992 if (sav) 993 KEY_FREESAV(&sav); 994 splx(s); 995 if (m) 996 m_freem(m); 997 free(tc, M_XDATA); 998 crypto_freereq(crp); 999 return error; 1000 } 1001 1002 static struct xformsw esp_xformsw = { 1003 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 1004 esp_init, esp_zeroize, esp_input, 1005 esp_output, 1006 NULL, 1007 }; 1008 1009 INITFN void 1010 esp_attach(void) 1011 { 1012 #define MAXIV(xform) \ 1013 if (xform.blocksize > esp_max_ivlen) \ 1014 esp_max_ivlen = xform.blocksize \ 1015 1016 esp_max_ivlen = 0; 1017 MAXIV(enc_xform_des); /* SADB_EALG_DESCBC */ 1018 MAXIV(enc_xform_3des); /* SADB_EALG_3DESCBC */ 1019 MAXIV(enc_xform_rijndael128); /* SADB_X_EALG_AES */ 1020 MAXIV(enc_xform_blf); /* SADB_X_EALG_BLOWFISHCBC */ 1021 MAXIV(enc_xform_cast5); /* SADB_X_EALG_CAST128CBC */ 1022 MAXIV(enc_xform_skipjack); /* SADB_X_EALG_SKIPJACK */ 1023 MAXIV(enc_xform_null); /* SADB_EALG_NULL */ 1024 1025 xform_register(&esp_xformsw); 1026 #undef MAXIV 1027 } 1028 #ifdef __FreeBSD__ 1029 SYSINIT(esp_xform_init, SI_SUB_DRIVERS, SI_ORDER_FIRST, esp_attach, NULL) 1030 #else 1031 #endif
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