1 /* $FreeBSD$ */ 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 #include <net/vnet.h> 52 53 #include <netinet/in.h> 54 #include <netinet/in_systm.h> 55 #include <netinet/ip.h> 56 #include <netinet/ip_ecn.h> 57 #include <netinet/ip6.h> 58 59 #include <net/route.h> 60 #include <netipsec/ipsec.h> 61 #include <netipsec/ah.h> 62 #include <netipsec/ah_var.h> 63 #include <netipsec/esp.h> 64 #include <netipsec/esp_var.h> 65 #include <netipsec/xform.h> 66 67 #ifdef INET6 68 #include <netinet6/ip6_var.h> 69 #include <netipsec/ipsec6.h> 70 #include <netinet6/ip6_ecn.h> 71 #endif 72 73 #include <netipsec/key.h> 74 #include <netipsec/key_debug.h> 75 76 #include <opencrypto/cryptodev.h> 77 #include <opencrypto/xform.h> 78 79 VNET_DEFINE(int, esp_enable) = 1; 80 VNET_DEFINE(struct espstat, espstat); 81 82 SYSCTL_DECL(_net_inet_esp); 83 SYSCTL_VNET_INT(_net_inet_esp, OID_AUTO, 84 esp_enable, CTLFLAG_RW, &VNET_NAME(esp_enable), 0, ""); 85 SYSCTL_VNET_STRUCT(_net_inet_esp, IPSECCTL_STATS, 86 stats, CTLFLAG_RD, &VNET_NAME(espstat), espstat, ""); 87 88 static int esp_input_cb(struct cryptop *op); 89 static int esp_output_cb(struct cryptop *crp); 90 91 /* 92 * NB: this is public for use by the PF_KEY support. 93 * NB: if you add support here; be sure to add code to esp_attach below! 94 */ 95 struct enc_xform * 96 esp_algorithm_lookup(int alg) 97 { 98 if (alg >= ESP_ALG_MAX) 99 return NULL; 100 switch (alg) { 101 case SADB_EALG_DESCBC: 102 return &enc_xform_des; 103 case SADB_EALG_3DESCBC: 104 return &enc_xform_3des; 105 case SADB_X_EALG_AES: 106 return &enc_xform_rijndael128; 107 case SADB_X_EALG_BLOWFISHCBC: 108 return &enc_xform_blf; 109 case SADB_X_EALG_CAST128CBC: 110 return &enc_xform_cast5; 111 case SADB_X_EALG_SKIPJACK: 112 return &enc_xform_skipjack; 113 case SADB_EALG_NULL: 114 return &enc_xform_null; 115 case SADB_X_EALG_CAMELLIACBC: 116 return &enc_xform_camellia; 117 } 118 return NULL; 119 } 120 121 size_t 122 esp_hdrsiz(struct secasvar *sav) 123 { 124 size_t size; 125 126 if (sav != NULL) { 127 /*XXX not right for null algorithm--does it matter??*/ 128 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 129 ("SA with null xform")); 130 if (sav->flags & SADB_X_EXT_OLD) 131 size = sizeof (struct esp); 132 else 133 size = sizeof (struct newesp); 134 size += sav->tdb_encalgxform->blocksize + 9; 135 /*XXX need alg check???*/ 136 if (sav->tdb_authalgxform != NULL && sav->replay) 137 size += ah_hdrsiz(sav); 138 } else { 139 /* 140 * base header size 141 * + max iv length for CBC mode 142 * + max pad length 143 * + sizeof (pad length field) 144 * + sizeof (next header field) 145 * + max icv supported. 146 */ 147 size = sizeof (struct newesp) + EALG_MAX_BLOCK_LEN + 9 + 16; 148 } 149 return size; 150 } 151 152 /* 153 * esp_init() is called when an SPI is being set up. 154 */ 155 static int 156 esp_init(struct secasvar *sav, struct xformsw *xsp) 157 { 158 struct enc_xform *txform; 159 struct cryptoini cria, crie; 160 int keylen; 161 int error; 162 163 txform = esp_algorithm_lookup(sav->alg_enc); 164 if (txform == NULL) { 165 DPRINTF(("%s: unsupported encryption algorithm %d\n", 166 __func__, sav->alg_enc)); 167 return EINVAL; 168 } 169 if (sav->key_enc == NULL) { 170 DPRINTF(("%s: no encoding key for %s algorithm\n", 171 __func__, txform->name)); 172 return EINVAL; 173 } 174 if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) { 175 DPRINTF(("%s: 4-byte IV not supported with protocol\n", 176 __func__)); 177 return EINVAL; 178 } 179 keylen = _KEYLEN(sav->key_enc); 180 if (txform->minkey > keylen || keylen > txform->maxkey) { 181 DPRINTF(("%s: invalid key length %u, must be in the range " 182 "[%u..%u] for algorithm %s\n", __func__, 183 keylen, txform->minkey, txform->maxkey, 184 txform->name)); 185 return EINVAL; 186 } 187 188 /* 189 * NB: The null xform needs a non-zero blocksize to keep the 190 * crypto code happy but if we use it to set ivlen then 191 * the ESP header will be processed incorrectly. The 192 * compromise is to force it to zero here. 193 */ 194 sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize); 195 sav->iv = (caddr_t) malloc(sav->ivlen, M_XDATA, M_WAITOK); 196 key_randomfill(sav->iv, sav->ivlen); /*XXX*/ 197 198 /* 199 * Setup AH-related state. 200 */ 201 if (sav->alg_auth != 0) { 202 error = ah_init0(sav, xsp, &cria); 203 if (error) 204 return error; 205 } 206 207 /* NB: override anything set in ah_init0 */ 208 sav->tdb_xform = xsp; 209 sav->tdb_encalgxform = txform; 210 211 /* Initialize crypto session. */ 212 bzero(&crie, sizeof (crie)); 213 crie.cri_alg = sav->tdb_encalgxform->type; 214 crie.cri_klen = _KEYBITS(sav->key_enc); 215 crie.cri_key = sav->key_enc->key_data; 216 /* XXX Rounds ? */ 217 218 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 219 /* init both auth & enc */ 220 crie.cri_next = &cria; 221 error = crypto_newsession(&sav->tdb_cryptoid, 222 &crie, V_crypto_support); 223 } else if (sav->tdb_encalgxform) { 224 error = crypto_newsession(&sav->tdb_cryptoid, 225 &crie, V_crypto_support); 226 } else if (sav->tdb_authalgxform) { 227 error = crypto_newsession(&sav->tdb_cryptoid, 228 &cria, V_crypto_support); 229 } else { 230 /* XXX cannot happen? */ 231 DPRINTF(("%s: no encoding OR authentication xform!\n", 232 __func__)); 233 error = EINVAL; 234 } 235 return error; 236 } 237 238 /* 239 * Paranoia. 240 */ 241 static int 242 esp_zeroize(struct secasvar *sav) 243 { 244 /* NB: ah_zerorize free's the crypto session state */ 245 int error = ah_zeroize(sav); 246 247 if (sav->key_enc) 248 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc)); 249 if (sav->iv) { 250 free(sav->iv, M_XDATA); 251 sav->iv = NULL; 252 } 253 sav->tdb_encalgxform = NULL; 254 sav->tdb_xform = NULL; 255 return error; 256 } 257 258 /* 259 * ESP input processing, called (eventually) through the protocol switch. 260 */ 261 static int 262 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 263 { 264 struct auth_hash *esph; 265 struct enc_xform *espx; 266 struct tdb_ident *tdbi; 267 struct tdb_crypto *tc; 268 int plen, alen, hlen; 269 struct m_tag *mtag; 270 struct newesp *esp; 271 272 struct cryptodesc *crde; 273 struct cryptop *crp; 274 275 IPSEC_ASSERT(sav != NULL, ("null SA")); 276 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); 277 278 /* Valid IP Packet length ? */ 279 if ( (skip&3) || (m->m_pkthdr.len&3) ){ 280 DPRINTF(("%s: misaligned packet, skip %u pkt len %u", 281 __func__, skip, m->m_pkthdr.len)); 282 V_espstat.esps_badilen++; 283 m_freem(m); 284 return EINVAL; 285 } 286 287 /* XXX don't pullup, just copy header */ 288 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 289 290 esph = sav->tdb_authalgxform; 291 espx = sav->tdb_encalgxform; 292 293 /* Determine the ESP header length */ 294 if (sav->flags & SADB_X_EXT_OLD) 295 hlen = sizeof (struct esp) + sav->ivlen; 296 else 297 hlen = sizeof (struct newesp) + sav->ivlen; 298 /* Authenticator hash size */ 299 if (esph != NULL) { 300 switch (esph->type) { 301 case CRYPTO_SHA2_256_HMAC: 302 case CRYPTO_SHA2_384_HMAC: 303 case CRYPTO_SHA2_512_HMAC: 304 alen = esph->hashsize/2; 305 break; 306 default: 307 alen = AH_HMAC_HASHLEN; 308 break; 309 } 310 }else 311 alen = 0; 312 313 /* 314 * Verify payload length is multiple of encryption algorithm 315 * block size. 316 * 317 * NB: This works for the null algorithm because the blocksize 318 * is 4 and all packets must be 4-byte aligned regardless 319 * of the algorithm. 320 */ 321 plen = m->m_pkthdr.len - (skip + hlen + alen); 322 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 323 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 324 " SA %s/%08lx\n", __func__, 325 plen, espx->blocksize, 326 ipsec_address(&sav->sah->saidx.dst), 327 (u_long) ntohl(sav->spi))); 328 V_espstat.esps_badilen++; 329 m_freem(m); 330 return EINVAL; 331 } 332 333 /* 334 * Check sequence number. 335 */ 336 if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) { 337 DPRINTF(("%s: packet replay check for %s\n", __func__, 338 ipsec_logsastr(sav))); /*XXX*/ 339 V_espstat.esps_replay++; 340 m_freem(m); 341 return ENOBUFS; /*XXX*/ 342 } 343 344 /* Update the counters */ 345 V_espstat.esps_ibytes += m->m_pkthdr.len - (skip + hlen + alen); 346 347 /* Find out if we've already done crypto */ 348 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL); 349 mtag != NULL; 350 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) { 351 tdbi = (struct tdb_ident *) (mtag + 1); 352 if (tdbi->proto == sav->sah->saidx.proto && 353 tdbi->spi == sav->spi && 354 !bcmp(&tdbi->dst, &sav->sah->saidx.dst, 355 sizeof(union sockaddr_union))) 356 break; 357 } 358 359 /* Get crypto descriptors */ 360 crp = crypto_getreq(esph && espx ? 2 : 1); 361 if (crp == NULL) { 362 DPRINTF(("%s: failed to acquire crypto descriptors\n", 363 __func__)); 364 V_espstat.esps_crypto++; 365 m_freem(m); 366 return ENOBUFS; 367 } 368 369 /* Get IPsec-specific opaque pointer */ 370 if (esph == NULL || mtag != NULL) 371 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 372 M_XDATA, M_NOWAIT|M_ZERO); 373 else 374 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen, 375 M_XDATA, M_NOWAIT|M_ZERO); 376 if (tc == NULL) { 377 crypto_freereq(crp); 378 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 379 V_espstat.esps_crypto++; 380 m_freem(m); 381 return ENOBUFS; 382 } 383 384 tc->tc_ptr = (caddr_t) mtag; 385 386 if (esph) { 387 struct cryptodesc *crda = crp->crp_desc; 388 389 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor")); 390 391 /* Authentication descriptor */ 392 crda->crd_skip = skip; 393 crda->crd_len = m->m_pkthdr.len - (skip + alen); 394 crda->crd_inject = m->m_pkthdr.len - alen; 395 396 crda->crd_alg = esph->type; 397 crda->crd_key = sav->key_auth->key_data; 398 crda->crd_klen = _KEYBITS(sav->key_auth); 399 400 /* Copy the authenticator */ 401 if (mtag == NULL) 402 m_copydata(m, m->m_pkthdr.len - alen, alen, 403 (caddr_t) (tc + 1)); 404 405 /* Chain authentication request */ 406 crde = crda->crd_next; 407 } else { 408 crde = crp->crp_desc; 409 } 410 411 /* Crypto operation descriptor */ 412 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 413 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 414 crp->crp_buf = (caddr_t) m; 415 crp->crp_callback = esp_input_cb; 416 crp->crp_sid = sav->tdb_cryptoid; 417 crp->crp_opaque = (caddr_t) tc; 418 419 /* These are passed as-is to the callback */ 420 tc->tc_spi = sav->spi; 421 tc->tc_dst = sav->sah->saidx.dst; 422 tc->tc_proto = sav->sah->saidx.proto; 423 tc->tc_protoff = protoff; 424 tc->tc_skip = skip; 425 KEY_ADDREFSA(sav); 426 tc->tc_sav = sav; 427 428 /* Decryption descriptor */ 429 if (espx) { 430 IPSEC_ASSERT(crde != NULL, ("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 = sav->key_enc->key_data; 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 /* 448 * ESP input callback from the crypto driver. 449 */ 450 static int 451 esp_input_cb(struct cryptop *crp) 452 { 453 u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN]; 454 int hlen, skip, protoff, error, alen; 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 crd = crp->crp_desc; 466 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!")); 467 468 tc = (struct tdb_crypto *) crp->crp_opaque; 469 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!")); 470 skip = tc->tc_skip; 471 protoff = tc->tc_protoff; 472 mtag = (struct m_tag *) tc->tc_ptr; 473 m = (struct mbuf *) crp->crp_buf; 474 475 sav = tc->tc_sav; 476 IPSEC_ASSERT(sav != NULL, ("null SA!")); 477 478 saidx = &sav->sah->saidx; 479 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 480 saidx->dst.sa.sa_family == AF_INET6, 481 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 482 483 esph = sav->tdb_authalgxform; 484 espx = sav->tdb_encalgxform; 485 486 /* Check for crypto errors */ 487 if (crp->crp_etype) { 488 /* Reset the session ID */ 489 if (sav->tdb_cryptoid != 0) 490 sav->tdb_cryptoid = crp->crp_sid; 491 492 if (crp->crp_etype == EAGAIN) 493 return (crypto_dispatch(crp)); 494 495 V_espstat.esps_noxform++; 496 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 497 error = crp->crp_etype; 498 goto bad; 499 } 500 501 /* Shouldn't happen... */ 502 if (m == NULL) { 503 V_espstat.esps_crypto++; 504 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 505 error = EINVAL; 506 goto bad; 507 } 508 V_espstat.esps_hist[sav->alg_enc]++; 509 510 /* If authentication was performed, check now. */ 511 if (esph != NULL) { 512 switch (esph->type) { 513 case CRYPTO_SHA2_256_HMAC: 514 case CRYPTO_SHA2_384_HMAC: 515 case CRYPTO_SHA2_512_HMAC: 516 alen = esph->hashsize/2; 517 break; 518 default: 519 alen = AH_HMAC_HASHLEN; 520 break; 521 } 522 /* 523 * If we have a tag, it means an IPsec-aware NIC did 524 * the verification for us. Otherwise we need to 525 * check the authentication calculation. 526 */ 527 V_ahstat.ahs_hist[sav->alg_auth]++; 528 if (mtag == NULL) { 529 /* Copy the authenticator from the packet */ 530 m_copydata(m, m->m_pkthdr.len - alen, 531 alen, aalg); 532 533 ptr = (caddr_t) (tc + 1); 534 535 /* Verify authenticator */ 536 if (bcmp(ptr, aalg, alen) != 0) { 537 DPRINTF(("%s: " 538 "authentication hash mismatch for packet in SA %s/%08lx\n", 539 __func__, 540 ipsec_address(&saidx->dst), 541 (u_long) ntohl(sav->spi))); 542 V_espstat.esps_badauth++; 543 error = EACCES; 544 goto bad; 545 } 546 } 547 548 /* Remove trailing authenticator */ 549 m_adj(m, -alen); 550 } 551 552 /* Release the crypto descriptors */ 553 free(tc, M_XDATA), tc = NULL; 554 crypto_freereq(crp), crp = NULL; 555 556 /* 557 * Packet is now decrypted. 558 */ 559 m->m_flags |= M_DECRYPTED; 560 561 /* 562 * Update replay sequence number, if appropriate. 563 */ 564 if (sav->replay) { 565 u_int32_t seq; 566 567 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 568 sizeof (seq), (caddr_t) &seq); 569 if (ipsec_updatereplay(ntohl(seq), sav)) { 570 DPRINTF(("%s: packet replay check for %s\n", __func__, 571 ipsec_logsastr(sav))); 572 V_espstat.esps_replay++; 573 error = ENOBUFS; 574 goto bad; 575 } 576 } 577 578 /* Determine the ESP header length */ 579 if (sav->flags & SADB_X_EXT_OLD) 580 hlen = sizeof (struct esp) + sav->ivlen; 581 else 582 hlen = sizeof (struct newesp) + sav->ivlen; 583 584 /* Remove the ESP header and IV from the mbuf. */ 585 error = m_striphdr(m, skip, hlen); 586 if (error) { 587 V_espstat.esps_hdrops++; 588 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 589 ipsec_address(&sav->sah->saidx.dst), 590 (u_long) ntohl(sav->spi))); 591 goto bad; 592 } 593 594 /* Save the last three bytes of decrypted data */ 595 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 596 597 /* Verify pad length */ 598 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 599 V_espstat.esps_badilen++; 600 DPRINTF(("%s: invalid padding length %d for %u byte packet " 601 "in SA %s/%08lx\n", __func__, 602 lastthree[1], m->m_pkthdr.len - skip, 603 ipsec_address(&sav->sah->saidx.dst), 604 (u_long) ntohl(sav->spi))); 605 error = EINVAL; 606 goto bad; 607 } 608 609 /* Verify correct decryption by checking the last padding bytes */ 610 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 611 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 612 V_espstat.esps_badenc++; 613 DPRINTF(("%s: decryption failed for packet in " 614 "SA %s/%08lx\n", __func__, 615 ipsec_address(&sav->sah->saidx.dst), 616 (u_long) ntohl(sav->spi))); 617 error = EINVAL; 618 goto bad; 619 } 620 } 621 622 /* Trim the mbuf chain to remove trailing authenticator and padding */ 623 m_adj(m, -(lastthree[1] + 2)); 624 625 /* Restore the Next Protocol field */ 626 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 627 628 switch (saidx->dst.sa.sa_family) { 629 #ifdef INET6 630 case AF_INET6: 631 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); 632 break; 633 #endif 634 #ifdef INET 635 case AF_INET: 636 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); 637 break; 638 #endif 639 default: 640 panic("%s: Unexpected address family: %d saidx=%p", __func__, 641 saidx->dst.sa.sa_family, saidx); 642 } 643 644 KEY_FREESAV(&sav); 645 return error; 646 bad: 647 if (sav) 648 KEY_FREESAV(&sav); 649 if (m != NULL) 650 m_freem(m); 651 if (tc != NULL) 652 free(tc, M_XDATA); 653 if (crp != NULL) 654 crypto_freereq(crp); 655 return error; 656 } 657 658 /* 659 * ESP output routine, called by ipsec[46]_process_packet(). 660 */ 661 static int 662 esp_output( 663 struct mbuf *m, 664 struct ipsecrequest *isr, 665 struct mbuf **mp, 666 int skip, 667 int protoff 668 ) 669 { 670 struct enc_xform *espx; 671 struct auth_hash *esph; 672 int hlen, rlen, padding, blks, alen, i, roff; 673 struct mbuf *mo = (struct mbuf *) NULL; 674 struct tdb_crypto *tc; 675 struct secasvar *sav; 676 struct secasindex *saidx; 677 unsigned char *pad; 678 u_int8_t prot; 679 int error, maxpacketsize; 680 681 struct cryptodesc *crde = NULL, *crda = NULL; 682 struct cryptop *crp; 683 684 sav = isr->sav; 685 IPSEC_ASSERT(sav != NULL, ("null SA")); 686 esph = sav->tdb_authalgxform; 687 espx = sav->tdb_encalgxform; 688 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 689 690 if (sav->flags & SADB_X_EXT_OLD) 691 hlen = sizeof (struct esp) + sav->ivlen; 692 else 693 hlen = sizeof (struct newesp) + sav->ivlen; 694 695 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 696 /* 697 * NB: The null encoding transform has a blocksize of 4 698 * so that headers are properly aligned. 699 */ 700 blks = espx->blocksize; /* IV blocksize */ 701 702 /* XXX clamp padding length a la KAME??? */ 703 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 704 705 if (esph) 706 switch (esph->type) { 707 case CRYPTO_SHA2_256_HMAC: 708 case CRYPTO_SHA2_384_HMAC: 709 case CRYPTO_SHA2_512_HMAC: 710 alen = esph->hashsize/2; 711 break; 712 default: 713 alen = AH_HMAC_HASHLEN; 714 break; 715 } 716 else 717 alen = 0; 718 719 V_espstat.esps_output++; 720 721 saidx = &sav->sah->saidx; 722 /* Check for maximum packet size violations. */ 723 switch (saidx->dst.sa.sa_family) { 724 #ifdef INET 725 case AF_INET: 726 maxpacketsize = IP_MAXPACKET; 727 break; 728 #endif /* INET */ 729 #ifdef INET6 730 case AF_INET6: 731 maxpacketsize = IPV6_MAXPACKET; 732 break; 733 #endif /* INET6 */ 734 default: 735 DPRINTF(("%s: unknown/unsupported protocol " 736 "family %d, SA %s/%08lx\n", __func__, 737 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst), 738 (u_long) ntohl(sav->spi))); 739 V_espstat.esps_nopf++; 740 error = EPFNOSUPPORT; 741 goto bad; 742 } 743 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 744 DPRINTF(("%s: packet in SA %s/%08lx got too big " 745 "(len %u, max len %u)\n", __func__, 746 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi), 747 skip + hlen + rlen + padding + alen, maxpacketsize)); 748 V_espstat.esps_toobig++; 749 error = EMSGSIZE; 750 goto bad; 751 } 752 753 /* Update the counters. */ 754 V_espstat.esps_obytes += m->m_pkthdr.len - skip; 755 756 m = m_unshare(m, M_NOWAIT); 757 if (m == NULL) { 758 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 759 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 760 V_espstat.esps_hdrops++; 761 error = ENOBUFS; 762 goto bad; 763 } 764 765 /* Inject ESP header. */ 766 mo = m_makespace(m, skip, hlen, &roff); 767 if (mo == NULL) { 768 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 769 __func__, hlen, ipsec_address(&saidx->dst), 770 (u_long) ntohl(sav->spi))); 771 V_espstat.esps_hdrops++; /* XXX diffs from openbsd */ 772 error = ENOBUFS; 773 goto bad; 774 } 775 776 /* Initialize ESP header. */ 777 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t)); 778 if (sav->replay) { 779 u_int32_t replay; 780 781 #ifdef REGRESSION 782 /* Emulate replay attack when ipsec_replay is TRUE. */ 783 if (!V_ipsec_replay) 784 #endif 785 sav->replay->count++; 786 replay = htonl(sav->replay->count); 787 bcopy((caddr_t) &replay, 788 mtod(mo, caddr_t) + roff + sizeof(u_int32_t), 789 sizeof(u_int32_t)); 790 } 791 792 /* 793 * Add padding -- better to do it ourselves than use the crypto engine, 794 * although if/when we support compression, we'd have to do that. 795 */ 796 pad = (u_char *) m_pad(m, padding + alen); 797 if (pad == NULL) { 798 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 799 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 800 m = NULL; /* NB: free'd by m_pad */ 801 error = ENOBUFS; 802 goto bad; 803 } 804 805 /* 806 * Add padding: random, zero, or self-describing. 807 * XXX catch unexpected setting 808 */ 809 switch (sav->flags & SADB_X_EXT_PMASK) { 810 case SADB_X_EXT_PRAND: 811 (void) read_random(pad, padding - 2); 812 break; 813 case SADB_X_EXT_PZERO: 814 bzero(pad, padding - 2); 815 break; 816 case SADB_X_EXT_PSEQ: 817 for (i = 0; i < padding - 2; i++) 818 pad[i] = i+1; 819 break; 820 } 821 822 /* Fix padding length and Next Protocol in padding itself. */ 823 pad[padding - 2] = padding - 2; 824 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 825 826 /* Fix Next Protocol in IPv4/IPv6 header. */ 827 prot = IPPROTO_ESP; 828 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 829 830 /* Get crypto descriptors. */ 831 crp = crypto_getreq(esph && espx ? 2 : 1); 832 if (crp == NULL) { 833 DPRINTF(("%s: failed to acquire crypto descriptors\n", 834 __func__)); 835 V_espstat.esps_crypto++; 836 error = ENOBUFS; 837 goto bad; 838 } 839 840 if (espx) { 841 crde = crp->crp_desc; 842 crda = crde->crd_next; 843 844 /* Encryption descriptor. */ 845 crde->crd_skip = skip + hlen; 846 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 847 crde->crd_flags = CRD_F_ENCRYPT; 848 crde->crd_inject = skip + hlen - sav->ivlen; 849 850 /* Encryption operation. */ 851 crde->crd_alg = espx->type; 852 crde->crd_key = sav->key_enc->key_data; 853 crde->crd_klen = _KEYBITS(sav->key_enc); 854 /* XXX Rounds ? */ 855 } else 856 crda = crp->crp_desc; 857 858 /* IPsec-specific opaque crypto info. */ 859 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 860 M_XDATA, M_NOWAIT|M_ZERO); 861 if (tc == NULL) { 862 crypto_freereq(crp); 863 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 864 V_espstat.esps_crypto++; 865 error = ENOBUFS; 866 goto bad; 867 } 868 869 /* Callback parameters */ 870 tc->tc_isr = isr; 871 KEY_ADDREFSA(sav); 872 tc->tc_sav = sav; 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 | CRYPTO_F_CBIFSYNC; 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 = sav->key_auth->key_data; 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 error; 915 916 tc = (struct tdb_crypto *) crp->crp_opaque; 917 IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); 918 m = (struct mbuf *) crp->crp_buf; 919 920 isr = tc->tc_isr; 921 IPSECREQUEST_LOCK(isr); 922 sav = tc->tc_sav; 923 /* With the isr lock released SA pointer can be updated. */ 924 if (sav != isr->sav) { 925 V_espstat.esps_notdb++; 926 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 927 __func__, ipsec_address(&tc->tc_dst), 928 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 929 error = ENOBUFS; /*XXX*/ 930 goto bad; 931 } 932 933 /* Check for crypto errors. */ 934 if (crp->crp_etype) { 935 /* Reset session ID. */ 936 if (sav->tdb_cryptoid != 0) 937 sav->tdb_cryptoid = crp->crp_sid; 938 939 if (crp->crp_etype == EAGAIN) { 940 IPSECREQUEST_UNLOCK(isr); 941 return (crypto_dispatch(crp)); 942 } 943 944 V_espstat.esps_noxform++; 945 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 946 error = crp->crp_etype; 947 goto bad; 948 } 949 950 /* Shouldn't happen... */ 951 if (m == NULL) { 952 V_espstat.esps_crypto++; 953 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 954 error = EINVAL; 955 goto bad; 956 } 957 V_espstat.esps_hist[sav->alg_enc]++; 958 if (sav->tdb_authalgxform != NULL) 959 V_ahstat.ahs_hist[sav->alg_auth]++; 960 961 /* Release crypto descriptors. */ 962 free(tc, M_XDATA); 963 crypto_freereq(crp); 964 965 #ifdef REGRESSION 966 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 967 if (V_ipsec_integrity) { 968 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN]; 969 struct auth_hash *esph; 970 971 /* 972 * Corrupt HMAC if we want to test integrity verification of 973 * the other side. 974 */ 975 esph = sav->tdb_authalgxform; 976 if (esph != NULL) { 977 int alen; 978 979 switch (esph->type) { 980 case CRYPTO_SHA2_256_HMAC: 981 case CRYPTO_SHA2_384_HMAC: 982 case CRYPTO_SHA2_512_HMAC: 983 alen = esph->hashsize/2; 984 break; 985 default: 986 alen = AH_HMAC_HASHLEN; 987 break; 988 } 989 m_copyback(m, m->m_pkthdr.len - alen, 990 alen, ipseczeroes); 991 } 992 } 993 #endif 994 995 /* NB: m is reclaimed by ipsec_process_done. */ 996 error = ipsec_process_done(m, isr); 997 KEY_FREESAV(&sav); 998 IPSECREQUEST_UNLOCK(isr); 999 return error; 1000 bad: 1001 if (sav) 1002 KEY_FREESAV(&sav); 1003 IPSECREQUEST_UNLOCK(isr); 1004 if (m) 1005 m_freem(m); 1006 free(tc, M_XDATA); 1007 crypto_freereq(crp); 1008 return error; 1009 } 1010 1011 static struct xformsw esp_xformsw = { 1012 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 1013 esp_init, esp_zeroize, esp_input, 1014 esp_output 1015 }; 1016 1017 static void 1018 esp_attach(void) 1019 { 1020 1021 xform_register(&esp_xformsw); 1022 } 1023 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL); 1024