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 KEY_ADDREFSA(sav); 433 tc->tc_sav = sav; 434 435 /* Decryption descriptor */ 436 if (espx) { 437 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor")); 438 crde->crd_skip = skip + hlen; 439 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 440 crde->crd_inject = skip + hlen - sav->ivlen; 441 442 crde->crd_alg = espx->type; 443 crde->crd_key = sav->key_enc->key_data; 444 crde->crd_klen = _KEYBITS(sav->key_enc); 445 /* XXX Rounds ? */ 446 } 447 448 if (mtag == NULL) 449 return crypto_dispatch(crp); 450 else 451 return esp_input_cb(crp); 452 } 453 454 #ifdef INET6 455 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \ 456 if (saidx->dst.sa.sa_family == AF_INET6) { \ 457 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \ 458 } else { \ 459 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \ 460 } \ 461 } while (0) 462 #else 463 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \ 464 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag)) 465 #endif 466 467 /* 468 * ESP input callback from the crypto driver. 469 */ 470 static int 471 esp_input_cb(struct cryptop *crp) 472 { 473 u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN]; 474 int hlen, skip, protoff, error, alen; 475 struct mbuf *m; 476 struct cryptodesc *crd; 477 struct auth_hash *esph; 478 struct enc_xform *espx; 479 struct tdb_crypto *tc; 480 struct m_tag *mtag; 481 struct secasvar *sav; 482 struct secasindex *saidx; 483 caddr_t ptr; 484 485 crd = crp->crp_desc; 486 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!")); 487 488 tc = (struct tdb_crypto *) crp->crp_opaque; 489 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!")); 490 skip = tc->tc_skip; 491 protoff = tc->tc_protoff; 492 mtag = (struct m_tag *) tc->tc_ptr; 493 m = (struct mbuf *) crp->crp_buf; 494 495 sav = tc->tc_sav; 496 IPSEC_ASSERT(sav != NULL, ("null SA!")); 497 498 saidx = &sav->sah->saidx; 499 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 500 saidx->dst.sa.sa_family == AF_INET6, 501 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 502 503 esph = sav->tdb_authalgxform; 504 espx = sav->tdb_encalgxform; 505 506 /* Check for crypto errors */ 507 if (crp->crp_etype) { 508 /* Reset the session ID */ 509 if (sav->tdb_cryptoid != 0) 510 sav->tdb_cryptoid = crp->crp_sid; 511 512 if (crp->crp_etype == EAGAIN) { 513 error = crypto_dispatch(crp); 514 return error; 515 } 516 517 V_espstat.esps_noxform++; 518 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 519 error = crp->crp_etype; 520 goto bad; 521 } 522 523 /* Shouldn't happen... */ 524 if (m == NULL) { 525 V_espstat.esps_crypto++; 526 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 527 error = EINVAL; 528 goto bad; 529 } 530 V_espstat.esps_hist[sav->alg_enc]++; 531 532 /* If authentication was performed, check now. */ 533 if (esph != NULL) { 534 switch (esph->type) { 535 case CRYPTO_SHA2_256_HMAC: 536 case CRYPTO_SHA2_384_HMAC: 537 case CRYPTO_SHA2_512_HMAC: 538 alen = esph->hashsize/2; 539 break; 540 default: 541 alen = AH_HMAC_HASHLEN; 542 break; 543 } 544 /* 545 * If we have a tag, it means an IPsec-aware NIC did 546 * the verification for us. Otherwise we need to 547 * check the authentication calculation. 548 */ 549 V_ahstat.ahs_hist[sav->alg_auth]++; 550 if (mtag == NULL) { 551 /* Copy the authenticator from the packet */ 552 m_copydata(m, m->m_pkthdr.len - alen, 553 alen, aalg); 554 555 ptr = (caddr_t) (tc + 1); 556 557 /* Verify authenticator */ 558 if (bcmp(ptr, aalg, alen) != 0) { 559 DPRINTF(("%s: " 560 "authentication hash mismatch for packet in SA %s/%08lx\n", 561 __func__, 562 ipsec_address(&saidx->dst), 563 (u_long) ntohl(sav->spi))); 564 V_espstat.esps_badauth++; 565 error = EACCES; 566 goto bad; 567 } 568 } 569 570 /* Remove trailing authenticator */ 571 m_adj(m, -alen); 572 } 573 574 /* Release the crypto descriptors */ 575 free(tc, M_XDATA), tc = NULL; 576 crypto_freereq(crp), crp = NULL; 577 578 /* 579 * Packet is now decrypted. 580 */ 581 m->m_flags |= M_DECRYPTED; 582 583 /* 584 * Update replay sequence number, if appropriate. 585 */ 586 if (sav->replay) { 587 u_int32_t seq; 588 589 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 590 sizeof (seq), (caddr_t) &seq); 591 if (ipsec_updatereplay(ntohl(seq), sav)) { 592 DPRINTF(("%s: packet replay check for %s\n", __func__, 593 ipsec_logsastr(sav))); 594 V_espstat.esps_replay++; 595 error = ENOBUFS; 596 goto bad; 597 } 598 } 599 600 /* Determine the ESP header length */ 601 if (sav->flags & SADB_X_EXT_OLD) 602 hlen = sizeof (struct esp) + sav->ivlen; 603 else 604 hlen = sizeof (struct newesp) + sav->ivlen; 605 606 /* Remove the ESP header and IV from the mbuf. */ 607 error = m_striphdr(m, skip, hlen); 608 if (error) { 609 V_espstat.esps_hdrops++; 610 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 611 ipsec_address(&sav->sah->saidx.dst), 612 (u_long) ntohl(sav->spi))); 613 goto bad; 614 } 615 616 /* Save the last three bytes of decrypted data */ 617 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 618 619 /* Verify pad length */ 620 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 621 V_espstat.esps_badilen++; 622 DPRINTF(("%s: invalid padding length %d for %u byte packet " 623 "in SA %s/%08lx\n", __func__, 624 lastthree[1], m->m_pkthdr.len - skip, 625 ipsec_address(&sav->sah->saidx.dst), 626 (u_long) ntohl(sav->spi))); 627 error = EINVAL; 628 goto bad; 629 } 630 631 /* Verify correct decryption by checking the last padding bytes */ 632 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 633 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 634 V_espstat.esps_badenc++; 635 DPRINTF(("%s: decryption failed for packet in " 636 "SA %s/%08lx\n", __func__, 637 ipsec_address(&sav->sah->saidx.dst), 638 (u_long) ntohl(sav->spi))); 639 error = EINVAL; 640 goto bad; 641 } 642 } 643 644 /* Trim the mbuf chain to remove trailing authenticator and padding */ 645 m_adj(m, -(lastthree[1] + 2)); 646 647 /* Restore the Next Protocol field */ 648 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 649 650 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag); 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, plen, 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 plen = rlen + padding; /* Padded payload length. */ 713 714 if (esph) 715 switch (esph->type) { 716 case CRYPTO_SHA2_256_HMAC: 717 case CRYPTO_SHA2_384_HMAC: 718 case CRYPTO_SHA2_512_HMAC: 719 alen = esph->hashsize/2; 720 break; 721 default: 722 alen = AH_HMAC_HASHLEN; 723 break; 724 } 725 else 726 alen = 0; 727 728 V_espstat.esps_output++; 729 730 saidx = &sav->sah->saidx; 731 /* Check for maximum packet size violations. */ 732 switch (saidx->dst.sa.sa_family) { 733 #ifdef INET 734 case AF_INET: 735 maxpacketsize = IP_MAXPACKET; 736 break; 737 #endif /* INET */ 738 #ifdef INET6 739 case AF_INET6: 740 maxpacketsize = IPV6_MAXPACKET; 741 break; 742 #endif /* INET6 */ 743 default: 744 DPRINTF(("%s: unknown/unsupported protocol " 745 "family %d, SA %s/%08lx\n", __func__, 746 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst), 747 (u_long) ntohl(sav->spi))); 748 V_espstat.esps_nopf++; 749 error = EPFNOSUPPORT; 750 goto bad; 751 } 752 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 753 DPRINTF(("%s: packet in SA %s/%08lx got too big " 754 "(len %u, max len %u)\n", __func__, 755 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi), 756 skip + hlen + rlen + padding + alen, maxpacketsize)); 757 V_espstat.esps_toobig++; 758 error = EMSGSIZE; 759 goto bad; 760 } 761 762 /* Update the counters. */ 763 V_espstat.esps_obytes += m->m_pkthdr.len - skip; 764 765 m = m_unshare(m, M_NOWAIT); 766 if (m == NULL) { 767 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 768 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 769 V_espstat.esps_hdrops++; 770 error = ENOBUFS; 771 goto bad; 772 } 773 774 /* Inject ESP header. */ 775 mo = m_makespace(m, skip, hlen, &roff); 776 if (mo == NULL) { 777 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 778 __func__, hlen, ipsec_address(&saidx->dst), 779 (u_long) ntohl(sav->spi))); 780 V_espstat.esps_hdrops++; /* XXX diffs from openbsd */ 781 error = ENOBUFS; 782 goto bad; 783 } 784 785 /* Initialize ESP header. */ 786 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t)); 787 if (sav->replay) { 788 u_int32_t replay; 789 790 #ifdef REGRESSION 791 /* Emulate replay attack when ipsec_replay is TRUE. */ 792 if (!V_ipsec_replay) 793 #endif 794 sav->replay->count++; 795 replay = htonl(sav->replay->count); 796 bcopy((caddr_t) &replay, 797 mtod(mo, caddr_t) + roff + sizeof(u_int32_t), 798 sizeof(u_int32_t)); 799 } 800 801 /* 802 * Add padding -- better to do it ourselves than use the crypto engine, 803 * although if/when we support compression, we'd have to do that. 804 */ 805 pad = (u_char *) m_pad(m, padding + alen); 806 if (pad == NULL) { 807 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 808 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 809 m = NULL; /* NB: free'd by m_pad */ 810 error = ENOBUFS; 811 goto bad; 812 } 813 814 /* 815 * Add padding: random, zero, or self-describing. 816 * XXX catch unexpected setting 817 */ 818 switch (sav->flags & SADB_X_EXT_PMASK) { 819 case SADB_X_EXT_PRAND: 820 (void) read_random(pad, padding - 2); 821 break; 822 case SADB_X_EXT_PZERO: 823 bzero(pad, padding - 2); 824 break; 825 case SADB_X_EXT_PSEQ: 826 for (i = 0; i < padding - 2; i++) 827 pad[i] = i+1; 828 break; 829 } 830 831 /* Fix padding length and Next Protocol in padding itself. */ 832 pad[padding - 2] = padding - 2; 833 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 834 835 /* Fix Next Protocol in IPv4/IPv6 header. */ 836 prot = IPPROTO_ESP; 837 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 838 839 /* Get crypto descriptors. */ 840 crp = crypto_getreq(esph && espx ? 2 : 1); 841 if (crp == NULL) { 842 DPRINTF(("%s: failed to acquire crypto descriptors\n", 843 __func__)); 844 V_espstat.esps_crypto++; 845 error = ENOBUFS; 846 goto bad; 847 } 848 849 if (espx) { 850 crde = crp->crp_desc; 851 crda = crde->crd_next; 852 853 /* Encryption descriptor. */ 854 crde->crd_skip = skip + hlen; 855 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 856 crde->crd_flags = CRD_F_ENCRYPT; 857 crde->crd_inject = skip + hlen - sav->ivlen; 858 859 /* Encryption operation. */ 860 crde->crd_alg = espx->type; 861 crde->crd_key = sav->key_enc->key_data; 862 crde->crd_klen = _KEYBITS(sav->key_enc); 863 /* XXX Rounds ? */ 864 } else 865 crda = crp->crp_desc; 866 867 /* IPsec-specific opaque crypto info. */ 868 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 869 M_XDATA, M_NOWAIT|M_ZERO); 870 if (tc == NULL) { 871 crypto_freereq(crp); 872 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 873 V_espstat.esps_crypto++; 874 error = ENOBUFS; 875 goto bad; 876 } 877 878 /* Callback parameters */ 879 tc->tc_isr = isr; 880 KEY_ADDREFSA(sav); 881 tc->tc_sav = sav; 882 tc->tc_spi = sav->spi; 883 tc->tc_dst = saidx->dst; 884 tc->tc_proto = saidx->proto; 885 886 /* Crypto operation descriptor. */ 887 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 888 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 889 crp->crp_buf = (caddr_t) m; 890 crp->crp_callback = esp_output_cb; 891 crp->crp_opaque = (caddr_t) tc; 892 crp->crp_sid = sav->tdb_cryptoid; 893 894 if (esph) { 895 /* Authentication descriptor. */ 896 crda->crd_skip = skip; 897 crda->crd_len = m->m_pkthdr.len - (skip + alen); 898 crda->crd_inject = m->m_pkthdr.len - alen; 899 900 /* Authentication operation. */ 901 crda->crd_alg = esph->type; 902 crda->crd_key = sav->key_auth->key_data; 903 crda->crd_klen = _KEYBITS(sav->key_auth); 904 } 905 906 return crypto_dispatch(crp); 907 bad: 908 if (m) 909 m_freem(m); 910 return (error); 911 } 912 913 /* 914 * ESP output callback from the crypto driver. 915 */ 916 static int 917 esp_output_cb(struct cryptop *crp) 918 { 919 struct tdb_crypto *tc; 920 struct ipsecrequest *isr; 921 struct secasvar *sav; 922 struct mbuf *m; 923 int err, error; 924 925 tc = (struct tdb_crypto *) crp->crp_opaque; 926 IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); 927 m = (struct mbuf *) crp->crp_buf; 928 929 isr = tc->tc_isr; 930 IPSECREQUEST_LOCK(isr); 931 sav = tc->tc_sav; 932 /* With the isr lock released SA pointer can be updated. */ 933 if (sav != isr->sav) { 934 V_espstat.esps_notdb++; 935 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 936 __func__, ipsec_address(&tc->tc_dst), 937 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 938 error = ENOBUFS; /*XXX*/ 939 goto bad; 940 } 941 942 /* Check for crypto errors. */ 943 if (crp->crp_etype) { 944 /* Reset session ID. */ 945 if (sav->tdb_cryptoid != 0) 946 sav->tdb_cryptoid = crp->crp_sid; 947 948 if (crp->crp_etype == EAGAIN) { 949 IPSECREQUEST_UNLOCK(isr); 950 error = crypto_dispatch(crp); 951 return error; 952 } 953 954 V_espstat.esps_noxform++; 955 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 956 error = crp->crp_etype; 957 goto bad; 958 } 959 960 /* Shouldn't happen... */ 961 if (m == NULL) { 962 V_espstat.esps_crypto++; 963 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 964 error = EINVAL; 965 goto bad; 966 } 967 V_espstat.esps_hist[sav->alg_enc]++; 968 if (sav->tdb_authalgxform != NULL) 969 V_ahstat.ahs_hist[sav->alg_auth]++; 970 971 /* Release crypto descriptors. */ 972 free(tc, M_XDATA); 973 crypto_freereq(crp); 974 975 #ifdef REGRESSION 976 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 977 if (V_ipsec_integrity) { 978 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN]; 979 struct auth_hash *esph; 980 981 /* 982 * Corrupt HMAC if we want to test integrity verification of 983 * the other side. 984 */ 985 esph = sav->tdb_authalgxform; 986 if (esph != NULL) { 987 int alen; 988 989 switch (esph->type) { 990 case CRYPTO_SHA2_256_HMAC: 991 case CRYPTO_SHA2_384_HMAC: 992 case CRYPTO_SHA2_512_HMAC: 993 alen = esph->hashsize/2; 994 break; 995 default: 996 alen = AH_HMAC_HASHLEN; 997 break; 998 } 999 m_copyback(m, m->m_pkthdr.len - alen, 1000 alen, ipseczeroes); 1001 } 1002 } 1003 #endif 1004 1005 /* NB: m is reclaimed by ipsec_process_done. */ 1006 err = ipsec_process_done(m, isr); 1007 KEY_FREESAV(&sav); 1008 IPSECREQUEST_UNLOCK(isr); 1009 return err; 1010 bad: 1011 if (sav) 1012 KEY_FREESAV(&sav); 1013 IPSECREQUEST_UNLOCK(isr); 1014 if (m) 1015 m_freem(m); 1016 free(tc, M_XDATA); 1017 crypto_freereq(crp); 1018 return error; 1019 } 1020 1021 static struct xformsw esp_xformsw = { 1022 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 1023 esp_init, esp_zeroize, esp_input, 1024 esp_output 1025 }; 1026 1027 static void 1028 esp_attach(void) 1029 { 1030 #define MAXIV(xform) \ 1031 if (xform.blocksize > V_esp_max_ivlen) \ 1032 V_esp_max_ivlen = xform.blocksize \ 1033 1034 MAXIV(enc_xform_des); /* SADB_EALG_DESCBC */ 1035 MAXIV(enc_xform_3des); /* SADB_EALG_3DESCBC */ 1036 MAXIV(enc_xform_rijndael128); /* SADB_X_EALG_AES */ 1037 MAXIV(enc_xform_blf); /* SADB_X_EALG_BLOWFISHCBC */ 1038 MAXIV(enc_xform_cast5); /* SADB_X_EALG_CAST128CBC */ 1039 MAXIV(enc_xform_skipjack); /* SADB_X_EALG_SKIPJACK */ 1040 MAXIV(enc_xform_null); /* SADB_EALG_NULL */ 1041 MAXIV(enc_xform_camellia); /* SADB_X_EALG_CAMELLIACBC */ 1042 1043 xform_register(&esp_xformsw); 1044 #undef MAXIV 1045 } 1046 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL); 1047