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 #include <sys/vimage.h> 50 51 #include <net/if.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 #ifdef VIMAGE_GLOBALS 80 struct espstat espstat; 81 static int esp_max_ivlen; /* max iv length over all algorithms */ 82 int esp_enable; 83 #endif 84 85 SYSCTL_DECL(_net_inet_esp); 86 SYSCTL_V_INT(V_NET, vnet_ipsec,_net_inet_esp, OID_AUTO, 87 esp_enable, CTLFLAG_RW, esp_enable, 0, ""); 88 SYSCTL_V_STRUCT(V_NET, vnet_ipsec, _net_inet_esp, IPSECCTL_STATS, 89 stats, CTLFLAG_RD, espstat, espstat, ""); 90 91 static int esp_input_cb(struct cryptop *op); 92 static int esp_output_cb(struct cryptop *crp); 93 static int esp_iattach(const void *); 94 95 #ifndef VIMAGE_GLOBALS 96 static const vnet_modinfo_t vnet_esp_modinfo = { 97 .vmi_id = VNET_MOD_ESP, 98 .vmi_name = "ipsec_esp", 99 .vmi_dependson = VNET_MOD_IPSEC, 100 .vmi_iattach = esp_iattach 101 }; 102 #endif /* !VIMAGE_GLOBALS */ 103 104 /* 105 * NB: this is public for use by the PF_KEY support. 106 * NB: if you add support here; be sure to add code to esp_attach below! 107 */ 108 struct enc_xform * 109 esp_algorithm_lookup(int alg) 110 { 111 if (alg >= ESP_ALG_MAX) 112 return NULL; 113 switch (alg) { 114 case SADB_EALG_DESCBC: 115 return &enc_xform_des; 116 case SADB_EALG_3DESCBC: 117 return &enc_xform_3des; 118 case SADB_X_EALG_AES: 119 return &enc_xform_rijndael128; 120 case SADB_X_EALG_BLOWFISHCBC: 121 return &enc_xform_blf; 122 case SADB_X_EALG_CAST128CBC: 123 return &enc_xform_cast5; 124 case SADB_X_EALG_SKIPJACK: 125 return &enc_xform_skipjack; 126 case SADB_EALG_NULL: 127 return &enc_xform_null; 128 case SADB_X_EALG_CAMELLIACBC: 129 return &enc_xform_camellia; 130 } 131 return NULL; 132 } 133 134 size_t 135 esp_hdrsiz(struct secasvar *sav) 136 { 137 INIT_VNET_IPSEC(curvnet); 138 size_t size; 139 140 if (sav != NULL) { 141 /*XXX not right for null algorithm--does it matter??*/ 142 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 143 ("SA with null xform")); 144 if (sav->flags & SADB_X_EXT_OLD) 145 size = sizeof (struct esp); 146 else 147 size = sizeof (struct newesp); 148 size += sav->tdb_encalgxform->blocksize + 9; 149 /*XXX need alg check???*/ 150 if (sav->tdb_authalgxform != NULL && sav->replay) 151 size += ah_hdrsiz(sav); 152 } else { 153 /* 154 * base header size 155 * + max iv length for CBC mode 156 * + max pad length 157 * + sizeof (pad length field) 158 * + sizeof (next header field) 159 * + max icv supported. 160 */ 161 size = sizeof (struct newesp) + V_esp_max_ivlen + 9 + 16; 162 } 163 return size; 164 } 165 166 /* 167 * esp_init() is called when an SPI is being set up. 168 */ 169 static int 170 esp_init(struct secasvar *sav, struct xformsw *xsp) 171 { 172 INIT_VNET_IPSEC(curvnet); 173 struct enc_xform *txform; 174 struct cryptoini cria, crie; 175 int keylen; 176 int error; 177 178 txform = esp_algorithm_lookup(sav->alg_enc); 179 if (txform == NULL) { 180 DPRINTF(("%s: unsupported encryption algorithm %d\n", 181 __func__, sav->alg_enc)); 182 return EINVAL; 183 } 184 if (sav->key_enc == NULL) { 185 DPRINTF(("%s: no encoding key for %s algorithm\n", 186 __func__, txform->name)); 187 return EINVAL; 188 } 189 if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) { 190 DPRINTF(("%s: 4-byte IV not supported with protocol\n", 191 __func__)); 192 return EINVAL; 193 } 194 keylen = _KEYLEN(sav->key_enc); 195 if (txform->minkey > keylen || keylen > txform->maxkey) { 196 DPRINTF(("%s: invalid key length %u, must be in the range " 197 "[%u..%u] for algorithm %s\n", __func__, 198 keylen, txform->minkey, txform->maxkey, 199 txform->name)); 200 return EINVAL; 201 } 202 203 /* 204 * NB: The null xform needs a non-zero blocksize to keep the 205 * crypto code happy but if we use it to set ivlen then 206 * the ESP header will be processed incorrectly. The 207 * compromise is to force it to zero here. 208 */ 209 sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize); 210 sav->iv = (caddr_t) malloc(sav->ivlen, M_XDATA, M_WAITOK); 211 if (sav->iv == NULL) { 212 DPRINTF(("%s: no memory for IV\n", __func__)); 213 return EINVAL; 214 } 215 key_randomfill(sav->iv, sav->ivlen); /*XXX*/ 216 217 /* 218 * Setup AH-related state. 219 */ 220 if (sav->alg_auth != 0) { 221 error = ah_init0(sav, xsp, &cria); 222 if (error) 223 return error; 224 } 225 226 /* NB: override anything set in ah_init0 */ 227 sav->tdb_xform = xsp; 228 sav->tdb_encalgxform = txform; 229 230 /* Initialize crypto session. */ 231 bzero(&crie, sizeof (crie)); 232 crie.cri_alg = sav->tdb_encalgxform->type; 233 crie.cri_klen = _KEYBITS(sav->key_enc); 234 crie.cri_key = sav->key_enc->key_data; 235 /* XXX Rounds ? */ 236 237 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 238 /* init both auth & enc */ 239 crie.cri_next = &cria; 240 error = crypto_newsession(&sav->tdb_cryptoid, 241 &crie, V_crypto_support); 242 } else if (sav->tdb_encalgxform) { 243 error = crypto_newsession(&sav->tdb_cryptoid, 244 &crie, V_crypto_support); 245 } else if (sav->tdb_authalgxform) { 246 error = crypto_newsession(&sav->tdb_cryptoid, 247 &cria, V_crypto_support); 248 } else { 249 /* XXX cannot happen? */ 250 DPRINTF(("%s: no encoding OR authentication xform!\n", 251 __func__)); 252 error = EINVAL; 253 } 254 return error; 255 } 256 257 /* 258 * Paranoia. 259 */ 260 static int 261 esp_zeroize(struct secasvar *sav) 262 { 263 /* NB: ah_zerorize free's the crypto session state */ 264 int error = ah_zeroize(sav); 265 266 if (sav->key_enc) 267 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc)); 268 if (sav->iv) { 269 free(sav->iv, M_XDATA); 270 sav->iv = NULL; 271 } 272 sav->tdb_encalgxform = NULL; 273 sav->tdb_xform = NULL; 274 return error; 275 } 276 277 /* 278 * ESP input processing, called (eventually) through the protocol switch. 279 */ 280 static int 281 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 282 { 283 INIT_VNET_IPSEC(curvnet); 284 struct auth_hash *esph; 285 struct enc_xform *espx; 286 struct tdb_ident *tdbi; 287 struct tdb_crypto *tc; 288 int plen, alen, hlen; 289 struct m_tag *mtag; 290 struct newesp *esp; 291 292 struct cryptodesc *crde; 293 struct cryptop *crp; 294 295 IPSEC_ASSERT(sav != NULL, ("null SA")); 296 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); 297 IPSEC_ASSERT((skip&3) == 0 && (m->m_pkthdr.len&3) == 0, 298 ("misaligned packet, skip %u pkt len %u", 299 skip, m->m_pkthdr.len)); 300 301 /* XXX don't pullup, just copy header */ 302 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 303 304 esph = sav->tdb_authalgxform; 305 espx = sav->tdb_encalgxform; 306 307 /* Determine the ESP header length */ 308 if (sav->flags & SADB_X_EXT_OLD) 309 hlen = sizeof (struct esp) + sav->ivlen; 310 else 311 hlen = sizeof (struct newesp) + sav->ivlen; 312 /* Authenticator hash size */ 313 alen = esph ? AH_HMAC_HASHLEN : 0; 314 315 /* 316 * Verify payload length is multiple of encryption algorithm 317 * block size. 318 * 319 * NB: This works for the null algorithm because the blocksize 320 * is 4 and all packets must be 4-byte aligned regardless 321 * of the algorithm. 322 */ 323 plen = m->m_pkthdr.len - (skip + hlen + alen); 324 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 325 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 326 " SA %s/%08lx\n", __func__, 327 plen, espx->blocksize, 328 ipsec_address(&sav->sah->saidx.dst), 329 (u_long) ntohl(sav->spi))); 330 V_espstat.esps_badilen++; 331 m_freem(m); 332 return EINVAL; 333 } 334 335 /* 336 * Check sequence number. 337 */ 338 if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) { 339 DPRINTF(("%s: packet replay check for %s\n", __func__, 340 ipsec_logsastr(sav))); /*XXX*/ 341 V_espstat.esps_replay++; 342 m_freem(m); 343 return ENOBUFS; /*XXX*/ 344 } 345 346 /* Update the counters */ 347 V_espstat.esps_ibytes += m->m_pkthdr.len - (skip + hlen + alen); 348 349 /* Find out if we've already done crypto */ 350 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL); 351 mtag != NULL; 352 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) { 353 tdbi = (struct tdb_ident *) (mtag + 1); 354 if (tdbi->proto == sav->sah->saidx.proto && 355 tdbi->spi == sav->spi && 356 !bcmp(&tdbi->dst, &sav->sah->saidx.dst, 357 sizeof(union sockaddr_union))) 358 break; 359 } 360 361 /* Get crypto descriptors */ 362 crp = crypto_getreq(esph && espx ? 2 : 1); 363 if (crp == NULL) { 364 DPRINTF(("%s: failed to acquire crypto descriptors\n", 365 __func__)); 366 V_espstat.esps_crypto++; 367 m_freem(m); 368 return ENOBUFS; 369 } 370 371 /* Get IPsec-specific opaque pointer */ 372 if (esph == NULL || mtag != NULL) 373 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 374 M_XDATA, M_NOWAIT|M_ZERO); 375 else 376 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen, 377 M_XDATA, M_NOWAIT|M_ZERO); 378 if (tc == NULL) { 379 crypto_freereq(crp); 380 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 381 V_espstat.esps_crypto++; 382 m_freem(m); 383 return ENOBUFS; 384 } 385 386 tc->tc_ptr = (caddr_t) mtag; 387 388 if (esph) { 389 struct cryptodesc *crda = crp->crp_desc; 390 391 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor")); 392 393 /* Authentication descriptor */ 394 crda->crd_skip = skip; 395 crda->crd_len = m->m_pkthdr.len - (skip + alen); 396 crda->crd_inject = m->m_pkthdr.len - alen; 397 398 crda->crd_alg = esph->type; 399 crda->crd_key = sav->key_auth->key_data; 400 crda->crd_klen = _KEYBITS(sav->key_auth); 401 402 /* Copy the authenticator */ 403 if (mtag == NULL) 404 m_copydata(m, m->m_pkthdr.len - alen, alen, 405 (caddr_t) (tc + 1)); 406 407 /* Chain authentication request */ 408 crde = crda->crd_next; 409 } else { 410 crde = crp->crp_desc; 411 } 412 413 /* Crypto operation descriptor */ 414 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 415 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 416 crp->crp_buf = (caddr_t) m; 417 crp->crp_callback = esp_input_cb; 418 crp->crp_sid = sav->tdb_cryptoid; 419 crp->crp_opaque = (caddr_t) tc; 420 421 /* These are passed as-is to the callback */ 422 tc->tc_spi = sav->spi; 423 tc->tc_dst = sav->sah->saidx.dst; 424 tc->tc_proto = sav->sah->saidx.proto; 425 tc->tc_protoff = protoff; 426 tc->tc_skip = skip; 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 #ifdef INET6 448 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \ 449 if (saidx->dst.sa.sa_family == AF_INET6) { \ 450 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \ 451 } else { \ 452 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \ 453 } \ 454 } while (0) 455 #else 456 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \ 457 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag)) 458 #endif 459 460 /* 461 * ESP input callback from the crypto driver. 462 */ 463 static int 464 esp_input_cb(struct cryptop *crp) 465 { 466 INIT_VNET_IPSEC(curvnet); 467 u_int8_t lastthree[3], aalg[AH_HMAC_HASHLEN]; 468 int hlen, skip, protoff, error; 469 struct mbuf *m; 470 struct cryptodesc *crd; 471 struct auth_hash *esph; 472 struct enc_xform *espx; 473 struct tdb_crypto *tc; 474 struct m_tag *mtag; 475 struct secasvar *sav; 476 struct secasindex *saidx; 477 caddr_t ptr; 478 479 crd = crp->crp_desc; 480 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!")); 481 482 tc = (struct tdb_crypto *) crp->crp_opaque; 483 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!")); 484 skip = tc->tc_skip; 485 protoff = tc->tc_protoff; 486 mtag = (struct m_tag *) tc->tc_ptr; 487 m = (struct mbuf *) crp->crp_buf; 488 489 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 490 if (sav == NULL) { 491 V_espstat.esps_notdb++; 492 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 493 __func__, ipsec_address(&tc->tc_dst), 494 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 495 error = ENOBUFS; /*XXX*/ 496 goto bad; 497 } 498 499 saidx = &sav->sah->saidx; 500 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 501 saidx->dst.sa.sa_family == AF_INET6, 502 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 503 504 esph = sav->tdb_authalgxform; 505 espx = sav->tdb_encalgxform; 506 507 /* Check for crypto errors */ 508 if (crp->crp_etype) { 509 /* Reset the session ID */ 510 if (sav->tdb_cryptoid != 0) 511 sav->tdb_cryptoid = crp->crp_sid; 512 513 if (crp->crp_etype == EAGAIN) { 514 KEY_FREESAV(&sav); 515 error = crypto_dispatch(crp); 516 return error; 517 } 518 519 V_espstat.esps_noxform++; 520 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 521 error = crp->crp_etype; 522 goto bad; 523 } 524 525 /* Shouldn't happen... */ 526 if (m == NULL) { 527 V_espstat.esps_crypto++; 528 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 529 error = EINVAL; 530 goto bad; 531 } 532 V_espstat.esps_hist[sav->alg_enc]++; 533 534 /* If authentication was performed, check now. */ 535 if (esph != NULL) { 536 /* 537 * If we have a tag, it means an IPsec-aware NIC did 538 * the verification for us. Otherwise we need to 539 * check the authentication calculation. 540 */ 541 V_ahstat.ahs_hist[sav->alg_auth]++; 542 if (mtag == NULL) { 543 /* Copy the authenticator from the packet */ 544 m_copydata(m, m->m_pkthdr.len - AH_HMAC_HASHLEN, 545 AH_HMAC_HASHLEN, aalg); 546 547 ptr = (caddr_t) (tc + 1); 548 549 /* Verify authenticator */ 550 if (bcmp(ptr, aalg, AH_HMAC_HASHLEN) != 0) { 551 DPRINTF(("%s: " 552 "authentication hash mismatch for packet in SA %s/%08lx\n", 553 __func__, 554 ipsec_address(&saidx->dst), 555 (u_long) ntohl(sav->spi))); 556 V_espstat.esps_badauth++; 557 error = EACCES; 558 goto bad; 559 } 560 } 561 562 /* Remove trailing authenticator */ 563 m_adj(m, -AH_HMAC_HASHLEN); 564 } 565 566 /* Release the crypto descriptors */ 567 free(tc, M_XDATA), tc = NULL; 568 crypto_freereq(crp), crp = NULL; 569 570 /* 571 * Packet is now decrypted. 572 */ 573 m->m_flags |= M_DECRYPTED; 574 575 /* 576 * Update replay sequence number, if appropriate. 577 */ 578 if (sav->replay) { 579 u_int32_t seq; 580 581 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 582 sizeof (seq), (caddr_t) &seq); 583 if (ipsec_updatereplay(ntohl(seq), sav)) { 584 DPRINTF(("%s: packet replay check for %s\n", __func__, 585 ipsec_logsastr(sav))); 586 V_espstat.esps_replay++; 587 error = ENOBUFS; 588 goto bad; 589 } 590 } 591 592 /* Determine the ESP header length */ 593 if (sav->flags & SADB_X_EXT_OLD) 594 hlen = sizeof (struct esp) + sav->ivlen; 595 else 596 hlen = sizeof (struct newesp) + sav->ivlen; 597 598 /* Remove the ESP header and IV from the mbuf. */ 599 error = m_striphdr(m, skip, hlen); 600 if (error) { 601 V_espstat.esps_hdrops++; 602 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 603 ipsec_address(&sav->sah->saidx.dst), 604 (u_long) ntohl(sav->spi))); 605 goto bad; 606 } 607 608 /* Save the last three bytes of decrypted data */ 609 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 610 611 /* Verify pad length */ 612 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 613 V_espstat.esps_badilen++; 614 DPRINTF(("%s: invalid padding length %d for %u byte packet " 615 "in SA %s/%08lx\n", __func__, 616 lastthree[1], m->m_pkthdr.len - skip, 617 ipsec_address(&sav->sah->saidx.dst), 618 (u_long) ntohl(sav->spi))); 619 error = EINVAL; 620 goto bad; 621 } 622 623 /* Verify correct decryption by checking the last padding bytes */ 624 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 625 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 626 V_espstat.esps_badenc++; 627 DPRINTF(("%s: decryption failed for packet in " 628 "SA %s/%08lx\n", __func__, 629 ipsec_address(&sav->sah->saidx.dst), 630 (u_long) ntohl(sav->spi))); 631 error = EINVAL; 632 goto bad; 633 } 634 } 635 636 /* Trim the mbuf chain to remove trailing authenticator and padding */ 637 m_adj(m, -(lastthree[1] + 2)); 638 639 /* Restore the Next Protocol field */ 640 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 641 642 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag); 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 INIT_VNET_IPSEC(curvnet); 671 struct enc_xform *espx; 672 struct auth_hash *esph; 673 int hlen, rlen, plen, padding, blks, alen, i, roff; 674 struct mbuf *mo = (struct mbuf *) NULL; 675 struct tdb_crypto *tc; 676 struct secasvar *sav; 677 struct secasindex *saidx; 678 unsigned char *pad; 679 u_int8_t prot; 680 int error, maxpacketsize; 681 682 struct cryptodesc *crde = NULL, *crda = NULL; 683 struct cryptop *crp; 684 685 sav = isr->sav; 686 IPSEC_ASSERT(sav != NULL, ("null SA")); 687 esph = sav->tdb_authalgxform; 688 espx = sav->tdb_encalgxform; 689 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 690 691 if (sav->flags & SADB_X_EXT_OLD) 692 hlen = sizeof (struct esp) + sav->ivlen; 693 else 694 hlen = sizeof (struct newesp) + sav->ivlen; 695 696 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 697 /* 698 * NB: The null encoding transform has a blocksize of 4 699 * so that headers are properly aligned. 700 */ 701 blks = espx->blocksize; /* IV blocksize */ 702 703 /* XXX clamp padding length a la KAME??? */ 704 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 705 plen = rlen + padding; /* Padded payload length. */ 706 707 if (esph) 708 alen = AH_HMAC_HASHLEN; 709 else 710 alen = 0; 711 712 V_espstat.esps_output++; 713 714 saidx = &sav->sah->saidx; 715 /* Check for maximum packet size violations. */ 716 switch (saidx->dst.sa.sa_family) { 717 #ifdef INET 718 case AF_INET: 719 maxpacketsize = IP_MAXPACKET; 720 break; 721 #endif /* INET */ 722 #ifdef INET6 723 case AF_INET6: 724 maxpacketsize = IPV6_MAXPACKET; 725 break; 726 #endif /* INET6 */ 727 default: 728 DPRINTF(("%s: unknown/unsupported protocol " 729 "family %d, SA %s/%08lx\n", __func__, 730 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst), 731 (u_long) ntohl(sav->spi))); 732 V_espstat.esps_nopf++; 733 error = EPFNOSUPPORT; 734 goto bad; 735 } 736 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 737 DPRINTF(("%s: packet in SA %s/%08lx got too big " 738 "(len %u, max len %u)\n", __func__, 739 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi), 740 skip + hlen + rlen + padding + alen, maxpacketsize)); 741 V_espstat.esps_toobig++; 742 error = EMSGSIZE; 743 goto bad; 744 } 745 746 /* Update the counters. */ 747 V_espstat.esps_obytes += m->m_pkthdr.len - skip; 748 749 m = m_unshare(m, M_NOWAIT); 750 if (m == NULL) { 751 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 752 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 753 V_espstat.esps_hdrops++; 754 error = ENOBUFS; 755 goto bad; 756 } 757 758 /* Inject ESP header. */ 759 mo = m_makespace(m, skip, hlen, &roff); 760 if (mo == NULL) { 761 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 762 __func__, hlen, ipsec_address(&saidx->dst), 763 (u_long) ntohl(sav->spi))); 764 V_espstat.esps_hdrops++; /* XXX diffs from openbsd */ 765 error = ENOBUFS; 766 goto bad; 767 } 768 769 /* Initialize ESP header. */ 770 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t)); 771 if (sav->replay) { 772 u_int32_t replay; 773 774 #ifdef REGRESSION 775 /* Emulate replay attack when ipsec_replay is TRUE. */ 776 if (!V_ipsec_replay) 777 #endif 778 sav->replay->count++; 779 replay = htonl(sav->replay->count); 780 bcopy((caddr_t) &replay, 781 mtod(mo, caddr_t) + roff + sizeof(u_int32_t), 782 sizeof(u_int32_t)); 783 } 784 785 /* 786 * Add padding -- better to do it ourselves than use the crypto engine, 787 * although if/when we support compression, we'd have to do that. 788 */ 789 pad = (u_char *) m_pad(m, padding + alen); 790 if (pad == NULL) { 791 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 792 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 793 m = NULL; /* NB: free'd by m_pad */ 794 error = ENOBUFS; 795 goto bad; 796 } 797 798 /* 799 * Add padding: random, zero, or self-describing. 800 * XXX catch unexpected setting 801 */ 802 switch (sav->flags & SADB_X_EXT_PMASK) { 803 case SADB_X_EXT_PRAND: 804 (void) read_random(pad, padding - 2); 805 break; 806 case SADB_X_EXT_PZERO: 807 bzero(pad, padding - 2); 808 break; 809 case SADB_X_EXT_PSEQ: 810 for (i = 0; i < padding - 2; i++) 811 pad[i] = i+1; 812 break; 813 } 814 815 /* Fix padding length and Next Protocol in padding itself. */ 816 pad[padding - 2] = padding - 2; 817 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 818 819 /* Fix Next Protocol in IPv4/IPv6 header. */ 820 prot = IPPROTO_ESP; 821 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 822 823 /* Get crypto descriptors. */ 824 crp = crypto_getreq(esph && espx ? 2 : 1); 825 if (crp == NULL) { 826 DPRINTF(("%s: failed to acquire crypto descriptors\n", 827 __func__)); 828 V_espstat.esps_crypto++; 829 error = ENOBUFS; 830 goto bad; 831 } 832 833 if (espx) { 834 crde = crp->crp_desc; 835 crda = crde->crd_next; 836 837 /* Encryption descriptor. */ 838 crde->crd_skip = skip + hlen; 839 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 840 crde->crd_flags = CRD_F_ENCRYPT; 841 crde->crd_inject = skip + hlen - sav->ivlen; 842 843 /* Encryption operation. */ 844 crde->crd_alg = espx->type; 845 crde->crd_key = sav->key_enc->key_data; 846 crde->crd_klen = _KEYBITS(sav->key_enc); 847 /* XXX Rounds ? */ 848 } else 849 crda = crp->crp_desc; 850 851 /* IPsec-specific opaque crypto info. */ 852 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 853 M_XDATA, M_NOWAIT|M_ZERO); 854 if (tc == NULL) { 855 crypto_freereq(crp); 856 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 857 V_espstat.esps_crypto++; 858 error = ENOBUFS; 859 goto bad; 860 } 861 862 /* Callback parameters */ 863 tc->tc_isr = isr; 864 tc->tc_spi = sav->spi; 865 tc->tc_dst = saidx->dst; 866 tc->tc_proto = saidx->proto; 867 868 /* Crypto operation descriptor. */ 869 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 870 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 871 crp->crp_buf = (caddr_t) m; 872 crp->crp_callback = esp_output_cb; 873 crp->crp_opaque = (caddr_t) tc; 874 crp->crp_sid = sav->tdb_cryptoid; 875 876 if (esph) { 877 /* Authentication descriptor. */ 878 crda->crd_skip = skip; 879 crda->crd_len = m->m_pkthdr.len - (skip + alen); 880 crda->crd_inject = m->m_pkthdr.len - alen; 881 882 /* Authentication operation. */ 883 crda->crd_alg = esph->type; 884 crda->crd_key = sav->key_auth->key_data; 885 crda->crd_klen = _KEYBITS(sav->key_auth); 886 } 887 888 return crypto_dispatch(crp); 889 bad: 890 if (m) 891 m_freem(m); 892 return (error); 893 } 894 895 /* 896 * ESP output callback from the crypto driver. 897 */ 898 static int 899 esp_output_cb(struct cryptop *crp) 900 { 901 INIT_VNET_IPSEC(curvnet); 902 struct tdb_crypto *tc; 903 struct ipsecrequest *isr; 904 struct secasvar *sav; 905 struct mbuf *m; 906 int err, error; 907 908 tc = (struct tdb_crypto *) crp->crp_opaque; 909 IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); 910 m = (struct mbuf *) crp->crp_buf; 911 912 isr = tc->tc_isr; 913 IPSECREQUEST_LOCK(isr); 914 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 915 if (sav == NULL) { 916 V_espstat.esps_notdb++; 917 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 918 __func__, ipsec_address(&tc->tc_dst), 919 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 920 error = ENOBUFS; /*XXX*/ 921 goto bad; 922 } 923 IPSEC_ASSERT(isr->sav == sav, 924 ("SA changed was %p now %p\n", isr->sav, sav)); 925 926 /* Check for crypto errors. */ 927 if (crp->crp_etype) { 928 /* Reset session ID. */ 929 if (sav->tdb_cryptoid != 0) 930 sav->tdb_cryptoid = crp->crp_sid; 931 932 if (crp->crp_etype == EAGAIN) { 933 KEY_FREESAV(&sav); 934 IPSECREQUEST_UNLOCK(isr); 935 error = crypto_dispatch(crp); 936 return error; 937 } 938 939 V_espstat.esps_noxform++; 940 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 941 error = crp->crp_etype; 942 goto bad; 943 } 944 945 /* Shouldn't happen... */ 946 if (m == NULL) { 947 V_espstat.esps_crypto++; 948 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 949 error = EINVAL; 950 goto bad; 951 } 952 V_espstat.esps_hist[sav->alg_enc]++; 953 if (sav->tdb_authalgxform != NULL) 954 V_ahstat.ahs_hist[sav->alg_auth]++; 955 956 /* Release crypto descriptors. */ 957 free(tc, M_XDATA); 958 crypto_freereq(crp); 959 960 #ifdef REGRESSION 961 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 962 if (V_ipsec_integrity) { 963 static unsigned char ipseczeroes[AH_HMAC_HASHLEN]; 964 struct auth_hash *esph; 965 966 /* 967 * Corrupt HMAC if we want to test integrity verification of 968 * the other side. 969 */ 970 esph = sav->tdb_authalgxform; 971 if (esph != NULL) { 972 m_copyback(m, m->m_pkthdr.len - AH_HMAC_HASHLEN, 973 AH_HMAC_HASHLEN, ipseczeroes); 974 } 975 } 976 #endif 977 978 /* NB: m is reclaimed by ipsec_process_done. */ 979 err = ipsec_process_done(m, isr); 980 KEY_FREESAV(&sav); 981 IPSECREQUEST_UNLOCK(isr); 982 return err; 983 bad: 984 if (sav) 985 KEY_FREESAV(&sav); 986 IPSECREQUEST_UNLOCK(isr); 987 if (m) 988 m_freem(m); 989 free(tc, M_XDATA); 990 crypto_freereq(crp); 991 return error; 992 } 993 994 static struct xformsw esp_xformsw = { 995 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 996 esp_init, esp_zeroize, esp_input, 997 esp_output 998 }; 999 1000 static void 1001 esp_attach(void) 1002 { 1003 1004 xform_register(&esp_xformsw); 1005 #ifndef VIMAGE_GLOBALS 1006 vnet_mod_register(&vnet_esp_modinfo); 1007 #else 1008 esp_iattach(NULL); 1009 #endif 1010 } 1011 1012 static int 1013 esp_iattach(const void *unused __unused) 1014 { 1015 INIT_VNET_IPSEC(curvnet); 1016 1017 #define MAXIV(xform) \ 1018 if (xform.blocksize > V_esp_max_ivlen) \ 1019 V_esp_max_ivlen = xform.blocksize \ 1020 1021 V_esp_enable = 1; 1022 V_esp_max_ivlen = 0; 1023 1024 MAXIV(enc_xform_des); /* SADB_EALG_DESCBC */ 1025 MAXIV(enc_xform_3des); /* SADB_EALG_3DESCBC */ 1026 MAXIV(enc_xform_rijndael128); /* SADB_X_EALG_AES */ 1027 MAXIV(enc_xform_blf); /* SADB_X_EALG_BLOWFISHCBC */ 1028 MAXIV(enc_xform_cast5); /* SADB_X_EALG_CAST128CBC */ 1029 MAXIV(enc_xform_skipjack); /* SADB_X_EALG_SKIPJACK */ 1030 MAXIV(enc_xform_null); /* SADB_EALG_NULL */ 1031 MAXIV(enc_xform_camellia); /* SADB_X_EALG_CAMELLIACBC */ 1032 #undef MAXIV 1033 1034 return (0); 1035 } 1036 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL); 1037