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/lock.h> 48 #include <sys/random.h> 49 #include <sys/rwlock.h> 50 #include <sys/sysctl.h> 51 52 #include <net/if.h> 53 #include <net/vnet.h> 54 55 #include <netinet/in.h> 56 #include <netinet/in_systm.h> 57 #include <netinet/ip.h> 58 #include <netinet/ip_ecn.h> 59 #include <netinet/ip6.h> 60 61 #include <net/route.h> 62 #include <netipsec/ipsec.h> 63 #include <netipsec/ah.h> 64 #include <netipsec/ah_var.h> 65 #include <netipsec/esp.h> 66 #include <netipsec/esp_var.h> 67 #include <netipsec/xform.h> 68 69 #ifdef INET6 70 #include <netinet6/ip6_var.h> 71 #include <netipsec/ipsec6.h> 72 #include <netinet6/ip6_ecn.h> 73 #endif 74 75 #include <netipsec/key.h> 76 #include <netipsec/key_debug.h> 77 78 #include <opencrypto/cryptodev.h> 79 #include <opencrypto/xform.h> 80 81 VNET_DEFINE(int, esp_enable) = 1; 82 VNET_PCPUSTAT_DEFINE(struct espstat, espstat); 83 VNET_PCPUSTAT_SYSINIT(espstat); 84 85 #ifdef VIMAGE 86 VNET_PCPUSTAT_SYSUNINIT(espstat); 87 #endif /* VIMAGE */ 88 89 SYSCTL_DECL(_net_inet_esp); 90 SYSCTL_VNET_INT(_net_inet_esp, OID_AUTO, 91 esp_enable, CTLFLAG_RW, &VNET_NAME(esp_enable), 0, ""); 92 SYSCTL_VNET_PCPUSTAT(_net_inet_esp, IPSECCTL_STATS, stats, 93 struct espstat, espstat, 94 "ESP statistics (struct espstat, netipsec/esp_var.h"); 95 96 static int esp_input_cb(struct cryptop *op); 97 static int esp_output_cb(struct cryptop *crp); 98 99 /* 100 * NB: this is public for use by the PF_KEY support. 101 * NB: if you add support here; be sure to add code to esp_attach below! 102 */ 103 struct enc_xform * 104 esp_algorithm_lookup(int alg) 105 { 106 if (alg >= ESP_ALG_MAX) 107 return NULL; 108 switch (alg) { 109 case SADB_EALG_DESCBC: 110 return &enc_xform_des; 111 case SADB_EALG_3DESCBC: 112 return &enc_xform_3des; 113 case SADB_X_EALG_AES: 114 return &enc_xform_rijndael128; 115 case SADB_X_EALG_BLOWFISHCBC: 116 return &enc_xform_blf; 117 case SADB_X_EALG_CAST128CBC: 118 return &enc_xform_cast5; 119 case SADB_X_EALG_SKIPJACK: 120 return &enc_xform_skipjack; 121 case SADB_EALG_NULL: 122 return &enc_xform_null; 123 case SADB_X_EALG_CAMELLIACBC: 124 return &enc_xform_camellia; 125 } 126 return NULL; 127 } 128 129 size_t 130 esp_hdrsiz(struct secasvar *sav) 131 { 132 size_t size; 133 134 if (sav != NULL) { 135 /*XXX not right for null algorithm--does it matter??*/ 136 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 137 ("SA with null xform")); 138 if (sav->flags & SADB_X_EXT_OLD) 139 size = sizeof (struct esp); 140 else 141 size = sizeof (struct newesp); 142 size += sav->tdb_encalgxform->blocksize + 9; 143 /*XXX need alg check???*/ 144 if (sav->tdb_authalgxform != NULL && sav->replay) 145 size += ah_hdrsiz(sav); 146 } else { 147 /* 148 * base header size 149 * + max iv length for CBC mode 150 * + max pad length 151 * + sizeof (pad length field) 152 * + sizeof (next header field) 153 * + max icv supported. 154 */ 155 size = sizeof (struct newesp) + EALG_MAX_BLOCK_LEN + 9 + 16; 156 } 157 return size; 158 } 159 160 /* 161 * esp_init() is called when an SPI is being set up. 162 */ 163 static int 164 esp_init(struct secasvar *sav, struct xformsw *xsp) 165 { 166 struct enc_xform *txform; 167 struct cryptoini cria, crie; 168 int keylen; 169 int error; 170 171 txform = esp_algorithm_lookup(sav->alg_enc); 172 if (txform == NULL) { 173 DPRINTF(("%s: unsupported encryption algorithm %d\n", 174 __func__, sav->alg_enc)); 175 return EINVAL; 176 } 177 if (sav->key_enc == NULL) { 178 DPRINTF(("%s: no encoding key for %s algorithm\n", 179 __func__, txform->name)); 180 return EINVAL; 181 } 182 if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) { 183 DPRINTF(("%s: 4-byte IV not supported with protocol\n", 184 __func__)); 185 return EINVAL; 186 } 187 keylen = _KEYLEN(sav->key_enc); 188 if (txform->minkey > keylen || keylen > txform->maxkey) { 189 DPRINTF(("%s: invalid key length %u, must be in the range " 190 "[%u..%u] for algorithm %s\n", __func__, 191 keylen, txform->minkey, txform->maxkey, 192 txform->name)); 193 return EINVAL; 194 } 195 196 /* 197 * NB: The null xform needs a non-zero blocksize to keep the 198 * crypto code happy but if we use it to set ivlen then 199 * the ESP header will be processed incorrectly. The 200 * compromise is to force it to zero here. 201 */ 202 sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize); 203 sav->iv = (caddr_t) malloc(sav->ivlen, M_XDATA, M_WAITOK); 204 key_randomfill(sav->iv, sav->ivlen); /*XXX*/ 205 206 /* 207 * Setup AH-related state. 208 */ 209 if (sav->alg_auth != 0) { 210 error = ah_init0(sav, xsp, &cria); 211 if (error) 212 return error; 213 } 214 215 /* NB: override anything set in ah_init0 */ 216 sav->tdb_xform = xsp; 217 sav->tdb_encalgxform = txform; 218 219 /* Initialize crypto session. */ 220 bzero(&crie, sizeof (crie)); 221 crie.cri_alg = sav->tdb_encalgxform->type; 222 crie.cri_klen = _KEYBITS(sav->key_enc); 223 crie.cri_key = sav->key_enc->key_data; 224 /* XXX Rounds ? */ 225 226 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 227 /* init both auth & enc */ 228 crie.cri_next = &cria; 229 error = crypto_newsession(&sav->tdb_cryptoid, 230 &crie, V_crypto_support); 231 } else if (sav->tdb_encalgxform) { 232 error = crypto_newsession(&sav->tdb_cryptoid, 233 &crie, V_crypto_support); 234 } else if (sav->tdb_authalgxform) { 235 error = crypto_newsession(&sav->tdb_cryptoid, 236 &cria, V_crypto_support); 237 } else { 238 /* XXX cannot happen? */ 239 DPRINTF(("%s: no encoding OR authentication xform!\n", 240 __func__)); 241 error = EINVAL; 242 } 243 return error; 244 } 245 246 /* 247 * Paranoia. 248 */ 249 static int 250 esp_zeroize(struct secasvar *sav) 251 { 252 /* NB: ah_zerorize free's the crypto session state */ 253 int error = ah_zeroize(sav); 254 255 if (sav->key_enc) 256 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc)); 257 if (sav->iv) { 258 free(sav->iv, M_XDATA); 259 sav->iv = NULL; 260 } 261 sav->tdb_encalgxform = NULL; 262 sav->tdb_xform = NULL; 263 return error; 264 } 265 266 /* 267 * ESP input processing, called (eventually) through the protocol switch. 268 */ 269 static int 270 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 271 { 272 struct auth_hash *esph; 273 struct enc_xform *espx; 274 struct tdb_ident *tdbi; 275 struct tdb_crypto *tc; 276 int plen, alen, hlen; 277 struct m_tag *mtag; 278 struct newesp *esp; 279 280 struct cryptodesc *crde; 281 struct cryptop *crp; 282 283 IPSEC_ASSERT(sav != NULL, ("null SA")); 284 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); 285 286 /* Valid IP Packet length ? */ 287 if ( (skip&3) || (m->m_pkthdr.len&3) ){ 288 DPRINTF(("%s: misaligned packet, skip %u pkt len %u", 289 __func__, skip, m->m_pkthdr.len)); 290 ESPSTAT_INC(esps_badilen); 291 m_freem(m); 292 return EINVAL; 293 } 294 295 /* XXX don't pullup, just copy header */ 296 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 297 298 esph = sav->tdb_authalgxform; 299 espx = sav->tdb_encalgxform; 300 301 /* Determine the ESP header length */ 302 if (sav->flags & SADB_X_EXT_OLD) 303 hlen = sizeof (struct esp) + sav->ivlen; 304 else 305 hlen = sizeof (struct newesp) + sav->ivlen; 306 /* Authenticator hash size */ 307 if (esph != NULL) { 308 switch (esph->type) { 309 case CRYPTO_SHA2_256_HMAC: 310 case CRYPTO_SHA2_384_HMAC: 311 case CRYPTO_SHA2_512_HMAC: 312 alen = esph->hashsize/2; 313 break; 314 default: 315 alen = AH_HMAC_HASHLEN; 316 break; 317 } 318 }else 319 alen = 0; 320 321 /* 322 * Verify payload length is multiple of encryption algorithm 323 * block size. 324 * 325 * NB: This works for the null algorithm because the blocksize 326 * is 4 and all packets must be 4-byte aligned regardless 327 * of the algorithm. 328 */ 329 plen = m->m_pkthdr.len - (skip + hlen + alen); 330 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 331 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 332 " SA %s/%08lx\n", __func__, 333 plen, espx->blocksize, 334 ipsec_address(&sav->sah->saidx.dst), 335 (u_long) ntohl(sav->spi))); 336 ESPSTAT_INC(esps_badilen); 337 m_freem(m); 338 return EINVAL; 339 } 340 341 /* 342 * Check sequence number. 343 */ 344 if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) { 345 DPRINTF(("%s: packet replay check for %s\n", __func__, 346 ipsec_logsastr(sav))); /*XXX*/ 347 ESPSTAT_INC(esps_replay); 348 m_freem(m); 349 return ENOBUFS; /*XXX*/ 350 } 351 352 /* Update the counters */ 353 ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen)); 354 355 /* Find out if we've already done crypto */ 356 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL); 357 mtag != NULL; 358 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) { 359 tdbi = (struct tdb_ident *) (mtag + 1); 360 if (tdbi->proto == sav->sah->saidx.proto && 361 tdbi->spi == sav->spi && 362 !bcmp(&tdbi->dst, &sav->sah->saidx.dst, 363 sizeof(union sockaddr_union))) 364 break; 365 } 366 367 /* Get crypto descriptors */ 368 crp = crypto_getreq(esph && espx ? 2 : 1); 369 if (crp == NULL) { 370 DPRINTF(("%s: failed to acquire crypto descriptors\n", 371 __func__)); 372 ESPSTAT_INC(esps_crypto); 373 m_freem(m); 374 return ENOBUFS; 375 } 376 377 /* Get IPsec-specific opaque pointer */ 378 if (esph == NULL || mtag != NULL) 379 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 380 M_XDATA, M_NOWAIT|M_ZERO); 381 else 382 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen, 383 M_XDATA, M_NOWAIT|M_ZERO); 384 if (tc == NULL) { 385 crypto_freereq(crp); 386 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 387 ESPSTAT_INC(esps_crypto); 388 m_freem(m); 389 return ENOBUFS; 390 } 391 392 tc->tc_ptr = (caddr_t) mtag; 393 394 if (esph) { 395 struct cryptodesc *crda = crp->crp_desc; 396 397 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor")); 398 399 /* Authentication descriptor */ 400 crda->crd_skip = skip; 401 crda->crd_len = m->m_pkthdr.len - (skip + alen); 402 crda->crd_inject = m->m_pkthdr.len - alen; 403 404 crda->crd_alg = esph->type; 405 crda->crd_key = sav->key_auth->key_data; 406 crda->crd_klen = _KEYBITS(sav->key_auth); 407 408 /* Copy the authenticator */ 409 if (mtag == NULL) 410 m_copydata(m, m->m_pkthdr.len - alen, alen, 411 (caddr_t) (tc + 1)); 412 413 /* Chain authentication request */ 414 crde = crda->crd_next; 415 } else { 416 crde = crp->crp_desc; 417 } 418 419 /* Crypto operation descriptor */ 420 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 421 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 422 crp->crp_buf = (caddr_t) m; 423 crp->crp_callback = esp_input_cb; 424 crp->crp_sid = sav->tdb_cryptoid; 425 crp->crp_opaque = (caddr_t) tc; 426 427 /* These are passed as-is to the callback */ 428 tc->tc_spi = sav->spi; 429 tc->tc_dst = sav->sah->saidx.dst; 430 tc->tc_proto = sav->sah->saidx.proto; 431 tc->tc_protoff = protoff; 432 tc->tc_skip = skip; 433 KEY_ADDREFSA(sav); 434 tc->tc_sav = sav; 435 436 /* Decryption descriptor */ 437 if (espx) { 438 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor")); 439 crde->crd_skip = skip + hlen; 440 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 441 crde->crd_inject = skip + hlen - sav->ivlen; 442 443 crde->crd_alg = espx->type; 444 crde->crd_key = sav->key_enc->key_data; 445 crde->crd_klen = _KEYBITS(sav->key_enc); 446 /* XXX Rounds ? */ 447 } 448 449 if (mtag == NULL) 450 return crypto_dispatch(crp); 451 else 452 return esp_input_cb(crp); 453 } 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_MAXHASHLEN]; 462 int hlen, skip, protoff, error, alen; 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, ("null crypto descriptor!")); 475 476 tc = (struct tdb_crypto *) crp->crp_opaque; 477 IPSEC_ASSERT(tc != NULL, ("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 sav = tc->tc_sav; 484 IPSEC_ASSERT(sav != NULL, ("null SA!")); 485 486 saidx = &sav->sah->saidx; 487 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 488 saidx->dst.sa.sa_family == AF_INET6, 489 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 490 491 esph = sav->tdb_authalgxform; 492 espx = sav->tdb_encalgxform; 493 494 /* Check for crypto errors */ 495 if (crp->crp_etype) { 496 /* Reset the session ID */ 497 if (sav->tdb_cryptoid != 0) 498 sav->tdb_cryptoid = crp->crp_sid; 499 500 if (crp->crp_etype == EAGAIN) 501 return (crypto_dispatch(crp)); 502 503 ESPSTAT_INC(esps_noxform); 504 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 505 error = crp->crp_etype; 506 goto bad; 507 } 508 509 /* Shouldn't happen... */ 510 if (m == NULL) { 511 ESPSTAT_INC(esps_crypto); 512 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 513 error = EINVAL; 514 goto bad; 515 } 516 ESPSTAT_INC(esps_hist[sav->alg_enc]); 517 518 /* If authentication was performed, check now. */ 519 if (esph != NULL) { 520 switch (esph->type) { 521 case CRYPTO_SHA2_256_HMAC: 522 case CRYPTO_SHA2_384_HMAC: 523 case CRYPTO_SHA2_512_HMAC: 524 alen = esph->hashsize/2; 525 break; 526 default: 527 alen = AH_HMAC_HASHLEN; 528 break; 529 } 530 /* 531 * If we have a tag, it means an IPsec-aware NIC did 532 * the verification for us. Otherwise we need to 533 * check the authentication calculation. 534 */ 535 AHSTAT_INC(ahs_hist[sav->alg_auth]); 536 if (mtag == NULL) { 537 /* Copy the authenticator from the packet */ 538 m_copydata(m, m->m_pkthdr.len - alen, 539 alen, aalg); 540 541 ptr = (caddr_t) (tc + 1); 542 543 /* Verify authenticator */ 544 if (bcmp(ptr, aalg, alen) != 0) { 545 DPRINTF(("%s: " 546 "authentication hash mismatch for packet in SA %s/%08lx\n", 547 __func__, 548 ipsec_address(&saidx->dst), 549 (u_long) ntohl(sav->spi))); 550 ESPSTAT_INC(esps_badauth); 551 error = EACCES; 552 goto bad; 553 } 554 } 555 556 /* Remove trailing authenticator */ 557 m_adj(m, -alen); 558 } 559 560 /* Release the crypto descriptors */ 561 free(tc, M_XDATA), tc = NULL; 562 crypto_freereq(crp), crp = NULL; 563 564 /* 565 * Packet is now decrypted. 566 */ 567 m->m_flags |= M_DECRYPTED; 568 569 /* 570 * Update replay sequence number, if appropriate. 571 */ 572 if (sav->replay) { 573 u_int32_t seq; 574 575 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 576 sizeof (seq), (caddr_t) &seq); 577 if (ipsec_updatereplay(ntohl(seq), sav)) { 578 DPRINTF(("%s: packet replay check for %s\n", __func__, 579 ipsec_logsastr(sav))); 580 ESPSTAT_INC(esps_replay); 581 error = ENOBUFS; 582 goto bad; 583 } 584 } 585 586 /* Determine the ESP header length */ 587 if (sav->flags & SADB_X_EXT_OLD) 588 hlen = sizeof (struct esp) + sav->ivlen; 589 else 590 hlen = sizeof (struct newesp) + sav->ivlen; 591 592 /* Remove the ESP header and IV from the mbuf. */ 593 error = m_striphdr(m, skip, hlen); 594 if (error) { 595 ESPSTAT_INC(esps_hdrops); 596 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 597 ipsec_address(&sav->sah->saidx.dst), 598 (u_long) ntohl(sav->spi))); 599 goto bad; 600 } 601 602 /* Save the last three bytes of decrypted data */ 603 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 604 605 /* Verify pad length */ 606 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 607 ESPSTAT_INC(esps_badilen); 608 DPRINTF(("%s: invalid padding length %d for %u byte packet " 609 "in SA %s/%08lx\n", __func__, 610 lastthree[1], m->m_pkthdr.len - skip, 611 ipsec_address(&sav->sah->saidx.dst), 612 (u_long) ntohl(sav->spi))); 613 error = EINVAL; 614 goto bad; 615 } 616 617 /* Verify correct decryption by checking the last padding bytes */ 618 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 619 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 620 ESPSTAT_INC(esps_badenc); 621 DPRINTF(("%s: decryption failed for packet in " 622 "SA %s/%08lx\n", __func__, 623 ipsec_address(&sav->sah->saidx.dst), 624 (u_long) ntohl(sav->spi))); 625 error = EINVAL; 626 goto bad; 627 } 628 } 629 630 /* Trim the mbuf chain to remove trailing authenticator and padding */ 631 m_adj(m, -(lastthree[1] + 2)); 632 633 /* Restore the Next Protocol field */ 634 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 635 636 switch (saidx->dst.sa.sa_family) { 637 #ifdef INET6 638 case AF_INET6: 639 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); 640 break; 641 #endif 642 #ifdef INET 643 case AF_INET: 644 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); 645 break; 646 #endif 647 default: 648 panic("%s: Unexpected address family: %d saidx=%p", __func__, 649 saidx->dst.sa.sa_family, saidx); 650 } 651 652 KEY_FREESAV(&sav); 653 return error; 654 bad: 655 if (sav) 656 KEY_FREESAV(&sav); 657 if (m != NULL) 658 m_freem(m); 659 if (tc != NULL) 660 free(tc, M_XDATA); 661 if (crp != NULL) 662 crypto_freereq(crp); 663 return error; 664 } 665 666 /* 667 * ESP output routine, called by ipsec[46]_process_packet(). 668 */ 669 static int 670 esp_output( 671 struct mbuf *m, 672 struct ipsecrequest *isr, 673 struct mbuf **mp, 674 int skip, 675 int protoff 676 ) 677 { 678 struct enc_xform *espx; 679 struct auth_hash *esph; 680 int hlen, rlen, padding, blks, alen, i, roff; 681 struct mbuf *mo = (struct mbuf *) NULL; 682 struct tdb_crypto *tc; 683 struct secasvar *sav; 684 struct secasindex *saidx; 685 unsigned char *pad; 686 u_int8_t prot; 687 int error, maxpacketsize; 688 689 struct cryptodesc *crde = NULL, *crda = NULL; 690 struct cryptop *crp; 691 692 sav = isr->sav; 693 IPSEC_ASSERT(sav != NULL, ("null SA")); 694 esph = sav->tdb_authalgxform; 695 espx = sav->tdb_encalgxform; 696 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 697 698 if (sav->flags & SADB_X_EXT_OLD) 699 hlen = sizeof (struct esp) + sav->ivlen; 700 else 701 hlen = sizeof (struct newesp) + sav->ivlen; 702 703 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 704 /* 705 * NB: The null encoding transform has a blocksize of 4 706 * so that headers are properly aligned. 707 */ 708 blks = espx->blocksize; /* IV blocksize */ 709 710 /* XXX clamp padding length a la KAME??? */ 711 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 712 713 if (esph) 714 switch (esph->type) { 715 case CRYPTO_SHA2_256_HMAC: 716 case CRYPTO_SHA2_384_HMAC: 717 case CRYPTO_SHA2_512_HMAC: 718 alen = esph->hashsize/2; 719 break; 720 default: 721 alen = AH_HMAC_HASHLEN; 722 break; 723 } 724 else 725 alen = 0; 726 727 ESPSTAT_INC(esps_output); 728 729 saidx = &sav->sah->saidx; 730 /* Check for maximum packet size violations. */ 731 switch (saidx->dst.sa.sa_family) { 732 #ifdef INET 733 case AF_INET: 734 maxpacketsize = IP_MAXPACKET; 735 break; 736 #endif /* INET */ 737 #ifdef INET6 738 case AF_INET6: 739 maxpacketsize = IPV6_MAXPACKET; 740 break; 741 #endif /* INET6 */ 742 default: 743 DPRINTF(("%s: unknown/unsupported protocol " 744 "family %d, SA %s/%08lx\n", __func__, 745 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst), 746 (u_long) ntohl(sav->spi))); 747 ESPSTAT_INC(esps_nopf); 748 error = EPFNOSUPPORT; 749 goto bad; 750 } 751 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 752 DPRINTF(("%s: packet in SA %s/%08lx got too big " 753 "(len %u, max len %u)\n", __func__, 754 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi), 755 skip + hlen + rlen + padding + alen, maxpacketsize)); 756 ESPSTAT_INC(esps_toobig); 757 error = EMSGSIZE; 758 goto bad; 759 } 760 761 /* Update the counters. */ 762 ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip); 763 764 m = m_unshare(m, M_NOWAIT); 765 if (m == NULL) { 766 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 767 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 768 ESPSTAT_INC(esps_hdrops); 769 error = ENOBUFS; 770 goto bad; 771 } 772 773 /* Inject ESP header. */ 774 mo = m_makespace(m, skip, hlen, &roff); 775 if (mo == NULL) { 776 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 777 __func__, hlen, ipsec_address(&saidx->dst), 778 (u_long) ntohl(sav->spi))); 779 ESPSTAT_INC(esps_hdrops); /* XXX diffs from openbsd */ 780 error = ENOBUFS; 781 goto bad; 782 } 783 784 /* Initialize ESP header. */ 785 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t)); 786 if (sav->replay) { 787 u_int32_t replay; 788 789 #ifdef REGRESSION 790 /* Emulate replay attack when ipsec_replay is TRUE. */ 791 if (!V_ipsec_replay) 792 #endif 793 sav->replay->count++; 794 replay = htonl(sav->replay->count); 795 bcopy((caddr_t) &replay, 796 mtod(mo, caddr_t) + roff + sizeof(u_int32_t), 797 sizeof(u_int32_t)); 798 } 799 800 /* 801 * Add padding -- better to do it ourselves than use the crypto engine, 802 * although if/when we support compression, we'd have to do that. 803 */ 804 pad = (u_char *) m_pad(m, padding + alen); 805 if (pad == NULL) { 806 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 807 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 808 m = NULL; /* NB: free'd by m_pad */ 809 error = ENOBUFS; 810 goto bad; 811 } 812 813 /* 814 * Add padding: random, zero, or self-describing. 815 * XXX catch unexpected setting 816 */ 817 switch (sav->flags & SADB_X_EXT_PMASK) { 818 case SADB_X_EXT_PRAND: 819 (void) read_random(pad, padding - 2); 820 break; 821 case SADB_X_EXT_PZERO: 822 bzero(pad, padding - 2); 823 break; 824 case SADB_X_EXT_PSEQ: 825 for (i = 0; i < padding - 2; i++) 826 pad[i] = i+1; 827 break; 828 } 829 830 /* Fix padding length and Next Protocol in padding itself. */ 831 pad[padding - 2] = padding - 2; 832 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 833 834 /* Fix Next Protocol in IPv4/IPv6 header. */ 835 prot = IPPROTO_ESP; 836 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 837 838 /* Get crypto descriptors. */ 839 crp = crypto_getreq(esph && espx ? 2 : 1); 840 if (crp == NULL) { 841 DPRINTF(("%s: failed to acquire crypto descriptors\n", 842 __func__)); 843 ESPSTAT_INC(esps_crypto); 844 error = ENOBUFS; 845 goto bad; 846 } 847 848 if (espx) { 849 crde = crp->crp_desc; 850 crda = crde->crd_next; 851 852 /* Encryption descriptor. */ 853 crde->crd_skip = skip + hlen; 854 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 855 crde->crd_flags = CRD_F_ENCRYPT; 856 crde->crd_inject = skip + hlen - sav->ivlen; 857 858 /* Encryption operation. */ 859 crde->crd_alg = espx->type; 860 crde->crd_key = sav->key_enc->key_data; 861 crde->crd_klen = _KEYBITS(sav->key_enc); 862 /* XXX Rounds ? */ 863 } else 864 crda = crp->crp_desc; 865 866 /* IPsec-specific opaque crypto info. */ 867 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 868 M_XDATA, M_NOWAIT|M_ZERO); 869 if (tc == NULL) { 870 crypto_freereq(crp); 871 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 872 ESPSTAT_INC(esps_crypto); 873 error = ENOBUFS; 874 goto bad; 875 } 876 877 /* Callback parameters */ 878 tc->tc_isr = isr; 879 KEY_ADDREFSA(sav); 880 tc->tc_sav = sav; 881 tc->tc_spi = sav->spi; 882 tc->tc_dst = saidx->dst; 883 tc->tc_proto = saidx->proto; 884 885 /* Crypto operation descriptor. */ 886 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 887 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 888 crp->crp_buf = (caddr_t) m; 889 crp->crp_callback = esp_output_cb; 890 crp->crp_opaque = (caddr_t) tc; 891 crp->crp_sid = sav->tdb_cryptoid; 892 893 if (esph) { 894 /* Authentication descriptor. */ 895 crda->crd_skip = skip; 896 crda->crd_len = m->m_pkthdr.len - (skip + alen); 897 crda->crd_inject = m->m_pkthdr.len - alen; 898 899 /* Authentication operation. */ 900 crda->crd_alg = esph->type; 901 crda->crd_key = sav->key_auth->key_data; 902 crda->crd_klen = _KEYBITS(sav->key_auth); 903 } 904 905 return crypto_dispatch(crp); 906 bad: 907 if (m) 908 m_freem(m); 909 return (error); 910 } 911 912 /* 913 * ESP output callback from the crypto driver. 914 */ 915 static int 916 esp_output_cb(struct cryptop *crp) 917 { 918 struct tdb_crypto *tc; 919 struct ipsecrequest *isr; 920 struct secasvar *sav; 921 struct mbuf *m; 922 int error; 923 924 tc = (struct tdb_crypto *) crp->crp_opaque; 925 IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); 926 m = (struct mbuf *) crp->crp_buf; 927 928 isr = tc->tc_isr; 929 IPSECREQUEST_LOCK(isr); 930 sav = tc->tc_sav; 931 /* With the isr lock released SA pointer can be updated. */ 932 if (sav != isr->sav) { 933 ESPSTAT_INC(esps_notdb); 934 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 935 __func__, ipsec_address(&tc->tc_dst), 936 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 937 error = ENOBUFS; /*XXX*/ 938 goto bad; 939 } 940 941 /* Check for crypto errors. */ 942 if (crp->crp_etype) { 943 /* Reset session ID. */ 944 if (sav->tdb_cryptoid != 0) 945 sav->tdb_cryptoid = crp->crp_sid; 946 947 if (crp->crp_etype == EAGAIN) { 948 IPSECREQUEST_UNLOCK(isr); 949 return (crypto_dispatch(crp)); 950 } 951 952 ESPSTAT_INC(esps_noxform); 953 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 954 error = crp->crp_etype; 955 goto bad; 956 } 957 958 /* Shouldn't happen... */ 959 if (m == NULL) { 960 ESPSTAT_INC(esps_crypto); 961 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 962 error = EINVAL; 963 goto bad; 964 } 965 ESPSTAT_INC(esps_hist[sav->alg_enc]); 966 if (sav->tdb_authalgxform != NULL) 967 AHSTAT_INC(ahs_hist[sav->alg_auth]); 968 969 /* Release crypto descriptors. */ 970 free(tc, M_XDATA); 971 crypto_freereq(crp); 972 973 #ifdef REGRESSION 974 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 975 if (V_ipsec_integrity) { 976 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN]; 977 struct auth_hash *esph; 978 979 /* 980 * Corrupt HMAC if we want to test integrity verification of 981 * the other side. 982 */ 983 esph = sav->tdb_authalgxform; 984 if (esph != NULL) { 985 int alen; 986 987 switch (esph->type) { 988 case CRYPTO_SHA2_256_HMAC: 989 case CRYPTO_SHA2_384_HMAC: 990 case CRYPTO_SHA2_512_HMAC: 991 alen = esph->hashsize/2; 992 break; 993 default: 994 alen = AH_HMAC_HASHLEN; 995 break; 996 } 997 m_copyback(m, m->m_pkthdr.len - alen, 998 alen, ipseczeroes); 999 } 1000 } 1001 #endif 1002 1003 /* NB: m is reclaimed by ipsec_process_done. */ 1004 error = ipsec_process_done(m, isr); 1005 KEY_FREESAV(&sav); 1006 IPSECREQUEST_UNLOCK(isr); 1007 return error; 1008 bad: 1009 if (sav) 1010 KEY_FREESAV(&sav); 1011 IPSECREQUEST_UNLOCK(isr); 1012 if (m) 1013 m_freem(m); 1014 free(tc, M_XDATA); 1015 crypto_freereq(crp); 1016 return error; 1017 } 1018 1019 static struct xformsw esp_xformsw = { 1020 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 1021 esp_init, esp_zeroize, esp_input, 1022 esp_output 1023 }; 1024 1025 static void 1026 esp_attach(void) 1027 { 1028 1029 xform_register(&esp_xformsw); 1030 } 1031 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL); 1032