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 VNET_DEFINE(int, esp_max_ivlen); /* max iv length over all algorithms */ 89 #define V_esp_max_ivlen VNET(esp_max_ivlen) 90 91 static int esp_input_cb(struct cryptop *op); 92 static int esp_output_cb(struct cryptop *crp); 93 94 /* 95 * NB: this is public for use by the PF_KEY support. 96 * NB: if you add support here; be sure to add code to esp_attach below! 97 */ 98 struct enc_xform * 99 esp_algorithm_lookup(int alg) 100 { 101 if (alg >= ESP_ALG_MAX) 102 return NULL; 103 switch (alg) { 104 case SADB_EALG_DESCBC: 105 return &enc_xform_des; 106 case SADB_EALG_3DESCBC: 107 return &enc_xform_3des; 108 case SADB_X_EALG_AES: 109 return &enc_xform_rijndael128; 110 case SADB_X_EALG_BLOWFISHCBC: 111 return &enc_xform_blf; 112 case SADB_X_EALG_CAST128CBC: 113 return &enc_xform_cast5; 114 case SADB_X_EALG_SKIPJACK: 115 return &enc_xform_skipjack; 116 case SADB_EALG_NULL: 117 return &enc_xform_null; 118 case SADB_X_EALG_CAMELLIACBC: 119 return &enc_xform_camellia; 120 } 121 return NULL; 122 } 123 124 size_t 125 esp_hdrsiz(struct secasvar *sav) 126 { 127 size_t size; 128 129 if (sav != NULL) { 130 /*XXX not right for null algorithm--does it matter??*/ 131 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 132 ("SA with null xform")); 133 if (sav->flags & SADB_X_EXT_OLD) 134 size = sizeof (struct esp); 135 else 136 size = sizeof (struct newesp); 137 size += sav->tdb_encalgxform->blocksize + 9; 138 /*XXX need alg check???*/ 139 if (sav->tdb_authalgxform != NULL && sav->replay) 140 size += ah_hdrsiz(sav); 141 } else { 142 /* 143 * base header size 144 * + max iv length for CBC mode 145 * + max pad length 146 * + sizeof (pad length field) 147 * + sizeof (next header field) 148 * + max icv supported. 149 */ 150 size = sizeof (struct newesp) + V_esp_max_ivlen + 9 + 16; 151 } 152 return size; 153 } 154 155 /* 156 * esp_init() is called when an SPI is being set up. 157 */ 158 static int 159 esp_init(struct secasvar *sav, struct xformsw *xsp) 160 { 161 struct enc_xform *txform; 162 struct cryptoini cria, crie; 163 int keylen; 164 int error; 165 166 txform = esp_algorithm_lookup(sav->alg_enc); 167 if (txform == NULL) { 168 DPRINTF(("%s: unsupported encryption algorithm %d\n", 169 __func__, sav->alg_enc)); 170 return EINVAL; 171 } 172 if (sav->key_enc == NULL) { 173 DPRINTF(("%s: no encoding key for %s algorithm\n", 174 __func__, txform->name)); 175 return EINVAL; 176 } 177 if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) { 178 DPRINTF(("%s: 4-byte IV not supported with protocol\n", 179 __func__)); 180 return EINVAL; 181 } 182 keylen = _KEYLEN(sav->key_enc); 183 if (txform->minkey > keylen || keylen > txform->maxkey) { 184 DPRINTF(("%s: invalid key length %u, must be in the range " 185 "[%u..%u] for algorithm %s\n", __func__, 186 keylen, txform->minkey, txform->maxkey, 187 txform->name)); 188 return EINVAL; 189 } 190 191 /* 192 * NB: The null xform needs a non-zero blocksize to keep the 193 * crypto code happy but if we use it to set ivlen then 194 * the ESP header will be processed incorrectly. The 195 * compromise is to force it to zero here. 196 */ 197 sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize); 198 sav->iv = (caddr_t) malloc(sav->ivlen, M_XDATA, M_WAITOK); 199 if (sav->iv == NULL) { 200 DPRINTF(("%s: no memory for IV\n", __func__)); 201 return EINVAL; 202 } 203 key_randomfill(sav->iv, sav->ivlen); /*XXX*/ 204 205 /* 206 * Setup AH-related state. 207 */ 208 if (sav->alg_auth != 0) { 209 error = ah_init0(sav, xsp, &cria); 210 if (error) 211 return error; 212 } 213 214 /* NB: override anything set in ah_init0 */ 215 sav->tdb_xform = xsp; 216 sav->tdb_encalgxform = txform; 217 218 /* Initialize crypto session. */ 219 bzero(&crie, sizeof (crie)); 220 crie.cri_alg = sav->tdb_encalgxform->type; 221 crie.cri_klen = _KEYBITS(sav->key_enc); 222 crie.cri_key = sav->key_enc->key_data; 223 /* XXX Rounds ? */ 224 225 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 226 /* init both auth & enc */ 227 crie.cri_next = &cria; 228 error = crypto_newsession(&sav->tdb_cryptoid, 229 &crie, V_crypto_support); 230 } else if (sav->tdb_encalgxform) { 231 error = crypto_newsession(&sav->tdb_cryptoid, 232 &crie, V_crypto_support); 233 } else if (sav->tdb_authalgxform) { 234 error = crypto_newsession(&sav->tdb_cryptoid, 235 &cria, V_crypto_support); 236 } else { 237 /* XXX cannot happen? */ 238 DPRINTF(("%s: no encoding OR authentication xform!\n", 239 __func__)); 240 error = EINVAL; 241 } 242 return error; 243 } 244 245 /* 246 * Paranoia. 247 */ 248 static int 249 esp_zeroize(struct secasvar *sav) 250 { 251 /* NB: ah_zerorize free's the crypto session state */ 252 int error = ah_zeroize(sav); 253 254 if (sav->key_enc) 255 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc)); 256 if (sav->iv) { 257 free(sav->iv, M_XDATA); 258 sav->iv = NULL; 259 } 260 sav->tdb_encalgxform = NULL; 261 sav->tdb_xform = NULL; 262 return error; 263 } 264 265 /* 266 * ESP input processing, called (eventually) through the protocol switch. 267 */ 268 static int 269 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 270 { 271 struct auth_hash *esph; 272 struct enc_xform *espx; 273 struct tdb_ident *tdbi; 274 struct tdb_crypto *tc; 275 int plen, alen, hlen; 276 struct m_tag *mtag; 277 struct newesp *esp; 278 279 struct cryptodesc *crde; 280 struct cryptop *crp; 281 282 IPSEC_ASSERT(sav != NULL, ("null SA")); 283 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); 284 285 /* Valid IP Packet length ? */ 286 if ( (skip&3) || (m->m_pkthdr.len&3) ){ 287 DPRINTF(("%s: misaligned packet, skip %u pkt len %u", 288 __func__, skip, m->m_pkthdr.len)); 289 V_espstat.esps_badilen++; 290 m_freem(m); 291 return EINVAL; 292 } 293 294 /* XXX don't pullup, just copy header */ 295 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 296 297 esph = sav->tdb_authalgxform; 298 espx = sav->tdb_encalgxform; 299 300 /* Determine the ESP header length */ 301 if (sav->flags & SADB_X_EXT_OLD) 302 hlen = sizeof (struct esp) + sav->ivlen; 303 else 304 hlen = sizeof (struct newesp) + sav->ivlen; 305 /* Authenticator hash size */ 306 if (esph != NULL) { 307 switch (esph->type) { 308 case CRYPTO_SHA2_256_HMAC: 309 case CRYPTO_SHA2_384_HMAC: 310 case CRYPTO_SHA2_512_HMAC: 311 alen = esph->hashsize/2; 312 break; 313 default: 314 alen = AH_HMAC_HASHLEN; 315 break; 316 } 317 }else 318 alen = 0; 319 320 /* 321 * Verify payload length is multiple of encryption algorithm 322 * block size. 323 * 324 * NB: This works for the null algorithm because the blocksize 325 * is 4 and all packets must be 4-byte aligned regardless 326 * of the algorithm. 327 */ 328 plen = m->m_pkthdr.len - (skip + hlen + alen); 329 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 330 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 331 " SA %s/%08lx\n", __func__, 332 plen, espx->blocksize, 333 ipsec_address(&sav->sah->saidx.dst), 334 (u_long) ntohl(sav->spi))); 335 V_espstat.esps_badilen++; 336 m_freem(m); 337 return EINVAL; 338 } 339 340 /* 341 * Check sequence number. 342 */ 343 if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) { 344 DPRINTF(("%s: packet replay check for %s\n", __func__, 345 ipsec_logsastr(sav))); /*XXX*/ 346 V_espstat.esps_replay++; 347 m_freem(m); 348 return ENOBUFS; /*XXX*/ 349 } 350 351 /* Update the counters */ 352 V_espstat.esps_ibytes += m->m_pkthdr.len - (skip + hlen + alen); 353 354 /* Find out if we've already done crypto */ 355 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL); 356 mtag != NULL; 357 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) { 358 tdbi = (struct tdb_ident *) (mtag + 1); 359 if (tdbi->proto == sav->sah->saidx.proto && 360 tdbi->spi == sav->spi && 361 !bcmp(&tdbi->dst, &sav->sah->saidx.dst, 362 sizeof(union sockaddr_union))) 363 break; 364 } 365 366 /* Get crypto descriptors */ 367 crp = crypto_getreq(esph && espx ? 2 : 1); 368 if (crp == NULL) { 369 DPRINTF(("%s: failed to acquire crypto descriptors\n", 370 __func__)); 371 V_espstat.esps_crypto++; 372 m_freem(m); 373 return ENOBUFS; 374 } 375 376 /* Get IPsec-specific opaque pointer */ 377 if (esph == NULL || mtag != NULL) 378 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 379 M_XDATA, M_NOWAIT|M_ZERO); 380 else 381 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen, 382 M_XDATA, M_NOWAIT|M_ZERO); 383 if (tc == NULL) { 384 crypto_freereq(crp); 385 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 386 V_espstat.esps_crypto++; 387 m_freem(m); 388 return ENOBUFS; 389 } 390 391 tc->tc_ptr = (caddr_t) mtag; 392 393 if (esph) { 394 struct cryptodesc *crda = crp->crp_desc; 395 396 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor")); 397 398 /* Authentication descriptor */ 399 crda->crd_skip = skip; 400 crda->crd_len = m->m_pkthdr.len - (skip + alen); 401 crda->crd_inject = m->m_pkthdr.len - alen; 402 403 crda->crd_alg = esph->type; 404 crda->crd_key = sav->key_auth->key_data; 405 crda->crd_klen = _KEYBITS(sav->key_auth); 406 407 /* Copy the authenticator */ 408 if (mtag == NULL) 409 m_copydata(m, m->m_pkthdr.len - alen, alen, 410 (caddr_t) (tc + 1)); 411 412 /* Chain authentication request */ 413 crde = crda->crd_next; 414 } else { 415 crde = crp->crp_desc; 416 } 417 418 /* Crypto operation descriptor */ 419 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 420 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 421 crp->crp_buf = (caddr_t) m; 422 crp->crp_callback = esp_input_cb; 423 crp->crp_sid = sav->tdb_cryptoid; 424 crp->crp_opaque = (caddr_t) tc; 425 426 /* These are passed as-is to the callback */ 427 tc->tc_spi = sav->spi; 428 tc->tc_dst = sav->sah->saidx.dst; 429 tc->tc_proto = sav->sah->saidx.proto; 430 tc->tc_protoff = protoff; 431 tc->tc_skip = skip; 432 433 /* Decryption descriptor */ 434 if (espx) { 435 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor")); 436 crde->crd_skip = skip + hlen; 437 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 438 crde->crd_inject = skip + hlen - sav->ivlen; 439 440 crde->crd_alg = espx->type; 441 crde->crd_key = sav->key_enc->key_data; 442 crde->crd_klen = _KEYBITS(sav->key_enc); 443 /* XXX Rounds ? */ 444 } 445 446 if (mtag == NULL) 447 return crypto_dispatch(crp); 448 else 449 return esp_input_cb(crp); 450 } 451 452 #ifdef INET6 453 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \ 454 if (saidx->dst.sa.sa_family == AF_INET6) { \ 455 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \ 456 } else { \ 457 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \ 458 } \ 459 } while (0) 460 #else 461 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \ 462 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag)) 463 #endif 464 465 /* 466 * ESP input callback from the crypto driver. 467 */ 468 static int 469 esp_input_cb(struct cryptop *crp) 470 { 471 u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN]; 472 int hlen, skip, protoff, error, alen; 473 struct mbuf *m; 474 struct cryptodesc *crd; 475 struct auth_hash *esph; 476 struct enc_xform *espx; 477 struct tdb_crypto *tc; 478 struct m_tag *mtag; 479 struct secasvar *sav; 480 struct secasindex *saidx; 481 caddr_t ptr; 482 483 crd = crp->crp_desc; 484 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!")); 485 486 tc = (struct tdb_crypto *) crp->crp_opaque; 487 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!")); 488 skip = tc->tc_skip; 489 protoff = tc->tc_protoff; 490 mtag = (struct m_tag *) tc->tc_ptr; 491 m = (struct mbuf *) crp->crp_buf; 492 493 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 494 if (sav == NULL) { 495 V_espstat.esps_notdb++; 496 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 497 __func__, ipsec_address(&tc->tc_dst), 498 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 499 error = ENOBUFS; /*XXX*/ 500 goto bad; 501 } 502 503 saidx = &sav->sah->saidx; 504 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 505 saidx->dst.sa.sa_family == AF_INET6, 506 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 507 508 esph = sav->tdb_authalgxform; 509 espx = sav->tdb_encalgxform; 510 511 /* Check for crypto errors */ 512 if (crp->crp_etype) { 513 /* Reset the session ID */ 514 if (sav->tdb_cryptoid != 0) 515 sav->tdb_cryptoid = crp->crp_sid; 516 517 if (crp->crp_etype == EAGAIN) { 518 KEY_FREESAV(&sav); 519 error = crypto_dispatch(crp); 520 return error; 521 } 522 523 V_espstat.esps_noxform++; 524 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 525 error = crp->crp_etype; 526 goto bad; 527 } 528 529 /* Shouldn't happen... */ 530 if (m == NULL) { 531 V_espstat.esps_crypto++; 532 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 533 error = EINVAL; 534 goto bad; 535 } 536 V_espstat.esps_hist[sav->alg_enc]++; 537 538 /* If authentication was performed, check now. */ 539 if (esph != NULL) { 540 switch (esph->type) { 541 case CRYPTO_SHA2_256_HMAC: 542 case CRYPTO_SHA2_384_HMAC: 543 case CRYPTO_SHA2_512_HMAC: 544 alen = esph->hashsize/2; 545 break; 546 default: 547 alen = AH_HMAC_HASHLEN; 548 break; 549 } 550 /* 551 * If we have a tag, it means an IPsec-aware NIC did 552 * the verification for us. Otherwise we need to 553 * check the authentication calculation. 554 */ 555 V_ahstat.ahs_hist[sav->alg_auth]++; 556 if (mtag == NULL) { 557 /* Copy the authenticator from the packet */ 558 m_copydata(m, m->m_pkthdr.len - alen, 559 alen, aalg); 560 561 ptr = (caddr_t) (tc + 1); 562 563 /* Verify authenticator */ 564 if (bcmp(ptr, aalg, alen) != 0) { 565 DPRINTF(("%s: " 566 "authentication hash mismatch for packet in SA %s/%08lx\n", 567 __func__, 568 ipsec_address(&saidx->dst), 569 (u_long) ntohl(sav->spi))); 570 V_espstat.esps_badauth++; 571 error = EACCES; 572 goto bad; 573 } 574 } 575 576 /* Remove trailing authenticator */ 577 m_adj(m, -alen); 578 } 579 580 /* Release the crypto descriptors */ 581 free(tc, M_XDATA), tc = NULL; 582 crypto_freereq(crp), crp = NULL; 583 584 /* 585 * Packet is now decrypted. 586 */ 587 m->m_flags |= M_DECRYPTED; 588 589 /* 590 * Update replay sequence number, if appropriate. 591 */ 592 if (sav->replay) { 593 u_int32_t seq; 594 595 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 596 sizeof (seq), (caddr_t) &seq); 597 if (ipsec_updatereplay(ntohl(seq), sav)) { 598 DPRINTF(("%s: packet replay check for %s\n", __func__, 599 ipsec_logsastr(sav))); 600 V_espstat.esps_replay++; 601 error = ENOBUFS; 602 goto bad; 603 } 604 } 605 606 /* Determine the ESP header length */ 607 if (sav->flags & SADB_X_EXT_OLD) 608 hlen = sizeof (struct esp) + sav->ivlen; 609 else 610 hlen = sizeof (struct newesp) + sav->ivlen; 611 612 /* Remove the ESP header and IV from the mbuf. */ 613 error = m_striphdr(m, skip, hlen); 614 if (error) { 615 V_espstat.esps_hdrops++; 616 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 617 ipsec_address(&sav->sah->saidx.dst), 618 (u_long) ntohl(sav->spi))); 619 goto bad; 620 } 621 622 /* Save the last three bytes of decrypted data */ 623 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 624 625 /* Verify pad length */ 626 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 627 V_espstat.esps_badilen++; 628 DPRINTF(("%s: invalid padding length %d for %u byte packet " 629 "in SA %s/%08lx\n", __func__, 630 lastthree[1], m->m_pkthdr.len - skip, 631 ipsec_address(&sav->sah->saidx.dst), 632 (u_long) ntohl(sav->spi))); 633 error = EINVAL; 634 goto bad; 635 } 636 637 /* Verify correct decryption by checking the last padding bytes */ 638 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 639 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 640 V_espstat.esps_badenc++; 641 DPRINTF(("%s: decryption failed for packet in " 642 "SA %s/%08lx\n", __func__, 643 ipsec_address(&sav->sah->saidx.dst), 644 (u_long) ntohl(sav->spi))); 645 error = EINVAL; 646 goto bad; 647 } 648 } 649 650 /* Trim the mbuf chain to remove trailing authenticator and padding */ 651 m_adj(m, -(lastthree[1] + 2)); 652 653 /* Restore the Next Protocol field */ 654 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 655 656 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag); 657 658 KEY_FREESAV(&sav); 659 return error; 660 bad: 661 if (sav) 662 KEY_FREESAV(&sav); 663 if (m != NULL) 664 m_freem(m); 665 if (tc != NULL) 666 free(tc, M_XDATA); 667 if (crp != NULL) 668 crypto_freereq(crp); 669 return error; 670 } 671 672 /* 673 * ESP output routine, called by ipsec[46]_process_packet(). 674 */ 675 static int 676 esp_output( 677 struct mbuf *m, 678 struct ipsecrequest *isr, 679 struct mbuf **mp, 680 int skip, 681 int protoff 682 ) 683 { 684 struct enc_xform *espx; 685 struct auth_hash *esph; 686 int hlen, rlen, plen, padding, blks, alen, i, roff; 687 struct mbuf *mo = (struct mbuf *) NULL; 688 struct tdb_crypto *tc; 689 struct secasvar *sav; 690 struct secasindex *saidx; 691 unsigned char *pad; 692 u_int8_t prot; 693 int error, maxpacketsize; 694 695 struct cryptodesc *crde = NULL, *crda = NULL; 696 struct cryptop *crp; 697 698 sav = isr->sav; 699 IPSEC_ASSERT(sav != NULL, ("null SA")); 700 esph = sav->tdb_authalgxform; 701 espx = sav->tdb_encalgxform; 702 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 703 704 if (sav->flags & SADB_X_EXT_OLD) 705 hlen = sizeof (struct esp) + sav->ivlen; 706 else 707 hlen = sizeof (struct newesp) + sav->ivlen; 708 709 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 710 /* 711 * NB: The null encoding transform has a blocksize of 4 712 * so that headers are properly aligned. 713 */ 714 blks = espx->blocksize; /* IV blocksize */ 715 716 /* XXX clamp padding length a la KAME??? */ 717 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 718 plen = rlen + padding; /* Padded payload length. */ 719 720 if (esph) 721 switch (esph->type) { 722 case CRYPTO_SHA2_256_HMAC: 723 case CRYPTO_SHA2_384_HMAC: 724 case CRYPTO_SHA2_512_HMAC: 725 alen = esph->hashsize/2; 726 break; 727 default: 728 alen = AH_HMAC_HASHLEN; 729 break; 730 } 731 else 732 alen = 0; 733 734 V_espstat.esps_output++; 735 736 saidx = &sav->sah->saidx; 737 /* Check for maximum packet size violations. */ 738 switch (saidx->dst.sa.sa_family) { 739 #ifdef INET 740 case AF_INET: 741 maxpacketsize = IP_MAXPACKET; 742 break; 743 #endif /* INET */ 744 #ifdef INET6 745 case AF_INET6: 746 maxpacketsize = IPV6_MAXPACKET; 747 break; 748 #endif /* INET6 */ 749 default: 750 DPRINTF(("%s: unknown/unsupported protocol " 751 "family %d, SA %s/%08lx\n", __func__, 752 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst), 753 (u_long) ntohl(sav->spi))); 754 V_espstat.esps_nopf++; 755 error = EPFNOSUPPORT; 756 goto bad; 757 } 758 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 759 DPRINTF(("%s: packet in SA %s/%08lx got too big " 760 "(len %u, max len %u)\n", __func__, 761 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi), 762 skip + hlen + rlen + padding + alen, maxpacketsize)); 763 V_espstat.esps_toobig++; 764 error = EMSGSIZE; 765 goto bad; 766 } 767 768 /* Update the counters. */ 769 V_espstat.esps_obytes += m->m_pkthdr.len - skip; 770 771 m = m_unshare(m, M_NOWAIT); 772 if (m == NULL) { 773 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 774 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 775 V_espstat.esps_hdrops++; 776 error = ENOBUFS; 777 goto bad; 778 } 779 780 /* Inject ESP header. */ 781 mo = m_makespace(m, skip, hlen, &roff); 782 if (mo == NULL) { 783 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 784 __func__, hlen, ipsec_address(&saidx->dst), 785 (u_long) ntohl(sav->spi))); 786 V_espstat.esps_hdrops++; /* XXX diffs from openbsd */ 787 error = ENOBUFS; 788 goto bad; 789 } 790 791 /* Initialize ESP header. */ 792 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t)); 793 if (sav->replay) { 794 u_int32_t replay; 795 796 #ifdef REGRESSION 797 /* Emulate replay attack when ipsec_replay is TRUE. */ 798 if (!V_ipsec_replay) 799 #endif 800 sav->replay->count++; 801 replay = htonl(sav->replay->count); 802 bcopy((caddr_t) &replay, 803 mtod(mo, caddr_t) + roff + sizeof(u_int32_t), 804 sizeof(u_int32_t)); 805 } 806 807 /* 808 * Add padding -- better to do it ourselves than use the crypto engine, 809 * although if/when we support compression, we'd have to do that. 810 */ 811 pad = (u_char *) m_pad(m, padding + alen); 812 if (pad == NULL) { 813 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 814 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 815 m = NULL; /* NB: free'd by m_pad */ 816 error = ENOBUFS; 817 goto bad; 818 } 819 820 /* 821 * Add padding: random, zero, or self-describing. 822 * XXX catch unexpected setting 823 */ 824 switch (sav->flags & SADB_X_EXT_PMASK) { 825 case SADB_X_EXT_PRAND: 826 (void) read_random(pad, padding - 2); 827 break; 828 case SADB_X_EXT_PZERO: 829 bzero(pad, padding - 2); 830 break; 831 case SADB_X_EXT_PSEQ: 832 for (i = 0; i < padding - 2; i++) 833 pad[i] = i+1; 834 break; 835 } 836 837 /* Fix padding length and Next Protocol in padding itself. */ 838 pad[padding - 2] = padding - 2; 839 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 840 841 /* Fix Next Protocol in IPv4/IPv6 header. */ 842 prot = IPPROTO_ESP; 843 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 844 845 /* Get crypto descriptors. */ 846 crp = crypto_getreq(esph && espx ? 2 : 1); 847 if (crp == NULL) { 848 DPRINTF(("%s: failed to acquire crypto descriptors\n", 849 __func__)); 850 V_espstat.esps_crypto++; 851 error = ENOBUFS; 852 goto bad; 853 } 854 855 if (espx) { 856 crde = crp->crp_desc; 857 crda = crde->crd_next; 858 859 /* Encryption descriptor. */ 860 crde->crd_skip = skip + hlen; 861 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 862 crde->crd_flags = CRD_F_ENCRYPT; 863 crde->crd_inject = skip + hlen - sav->ivlen; 864 865 /* Encryption operation. */ 866 crde->crd_alg = espx->type; 867 crde->crd_key = sav->key_enc->key_data; 868 crde->crd_klen = _KEYBITS(sav->key_enc); 869 /* XXX Rounds ? */ 870 } else 871 crda = crp->crp_desc; 872 873 /* IPsec-specific opaque crypto info. */ 874 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 875 M_XDATA, M_NOWAIT|M_ZERO); 876 if (tc == NULL) { 877 crypto_freereq(crp); 878 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 879 V_espstat.esps_crypto++; 880 error = ENOBUFS; 881 goto bad; 882 } 883 884 /* Callback parameters */ 885 tc->tc_isr = isr; 886 tc->tc_spi = sav->spi; 887 tc->tc_dst = saidx->dst; 888 tc->tc_proto = saidx->proto; 889 890 /* Crypto operation descriptor. */ 891 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 892 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 893 crp->crp_buf = (caddr_t) m; 894 crp->crp_callback = esp_output_cb; 895 crp->crp_opaque = (caddr_t) tc; 896 crp->crp_sid = sav->tdb_cryptoid; 897 898 if (esph) { 899 /* Authentication descriptor. */ 900 crda->crd_skip = skip; 901 crda->crd_len = m->m_pkthdr.len - (skip + alen); 902 crda->crd_inject = m->m_pkthdr.len - alen; 903 904 /* Authentication operation. */ 905 crda->crd_alg = esph->type; 906 crda->crd_key = sav->key_auth->key_data; 907 crda->crd_klen = _KEYBITS(sav->key_auth); 908 } 909 910 return crypto_dispatch(crp); 911 bad: 912 if (m) 913 m_freem(m); 914 return (error); 915 } 916 917 /* 918 * ESP output callback from the crypto driver. 919 */ 920 static int 921 esp_output_cb(struct cryptop *crp) 922 { 923 struct tdb_crypto *tc; 924 struct ipsecrequest *isr; 925 struct secasvar *sav; 926 struct mbuf *m; 927 int err, error; 928 929 tc = (struct tdb_crypto *) crp->crp_opaque; 930 IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); 931 m = (struct mbuf *) crp->crp_buf; 932 933 isr = tc->tc_isr; 934 IPSECREQUEST_LOCK(isr); 935 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 936 if (sav == NULL) { 937 V_espstat.esps_notdb++; 938 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 939 __func__, ipsec_address(&tc->tc_dst), 940 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 941 error = ENOBUFS; /*XXX*/ 942 goto bad; 943 } 944 IPSEC_ASSERT(isr->sav == sav, 945 ("SA changed was %p now %p\n", isr->sav, sav)); 946 947 /* Check for crypto errors. */ 948 if (crp->crp_etype) { 949 /* Reset session ID. */ 950 if (sav->tdb_cryptoid != 0) 951 sav->tdb_cryptoid = crp->crp_sid; 952 953 if (crp->crp_etype == EAGAIN) { 954 KEY_FREESAV(&sav); 955 IPSECREQUEST_UNLOCK(isr); 956 error = crypto_dispatch(crp); 957 return error; 958 } 959 960 V_espstat.esps_noxform++; 961 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 962 error = crp->crp_etype; 963 goto bad; 964 } 965 966 /* Shouldn't happen... */ 967 if (m == NULL) { 968 V_espstat.esps_crypto++; 969 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 970 error = EINVAL; 971 goto bad; 972 } 973 V_espstat.esps_hist[sav->alg_enc]++; 974 if (sav->tdb_authalgxform != NULL) 975 V_ahstat.ahs_hist[sav->alg_auth]++; 976 977 /* Release crypto descriptors. */ 978 free(tc, M_XDATA); 979 crypto_freereq(crp); 980 981 #ifdef REGRESSION 982 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 983 if (V_ipsec_integrity) { 984 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN]; 985 struct auth_hash *esph; 986 987 /* 988 * Corrupt HMAC if we want to test integrity verification of 989 * the other side. 990 */ 991 esph = sav->tdb_authalgxform; 992 if (esph != NULL) { 993 int alen; 994 995 switch (esph->type) { 996 case CRYPTO_SHA2_256_HMAC: 997 case CRYPTO_SHA2_384_HMAC: 998 case CRYPTO_SHA2_512_HMAC: 999 alen = esph->hashsize/2; 1000 break; 1001 default: 1002 alen = AH_HMAC_HASHLEN; 1003 break; 1004 } 1005 m_copyback(m, m->m_pkthdr.len - alen, 1006 alen, ipseczeroes); 1007 } 1008 } 1009 #endif 1010 1011 /* NB: m is reclaimed by ipsec_process_done. */ 1012 err = ipsec_process_done(m, isr); 1013 KEY_FREESAV(&sav); 1014 IPSECREQUEST_UNLOCK(isr); 1015 return err; 1016 bad: 1017 if (sav) 1018 KEY_FREESAV(&sav); 1019 IPSECREQUEST_UNLOCK(isr); 1020 if (m) 1021 m_freem(m); 1022 free(tc, M_XDATA); 1023 crypto_freereq(crp); 1024 return error; 1025 } 1026 1027 static struct xformsw esp_xformsw = { 1028 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 1029 esp_init, esp_zeroize, esp_input, 1030 esp_output 1031 }; 1032 1033 static void 1034 esp_attach(void) 1035 { 1036 #define MAXIV(xform) \ 1037 if (xform.blocksize > V_esp_max_ivlen) \ 1038 V_esp_max_ivlen = xform.blocksize \ 1039 1040 MAXIV(enc_xform_des); /* SADB_EALG_DESCBC */ 1041 MAXIV(enc_xform_3des); /* SADB_EALG_3DESCBC */ 1042 MAXIV(enc_xform_rijndael128); /* SADB_X_EALG_AES */ 1043 MAXIV(enc_xform_blf); /* SADB_X_EALG_BLOWFISHCBC */ 1044 MAXIV(enc_xform_cast5); /* SADB_X_EALG_CAST128CBC */ 1045 MAXIV(enc_xform_skipjack); /* SADB_X_EALG_SKIPJACK */ 1046 MAXIV(enc_xform_null); /* SADB_EALG_NULL */ 1047 MAXIV(enc_xform_camellia); /* SADB_X_EALG_CAMELLIACBC */ 1048 1049 xform_register(&esp_xformsw); 1050 #undef MAXIV 1051 } 1052 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL); 1053