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 <netipsec/ipsec.h> 62 #include <netipsec/ah.h> 63 #include <netipsec/ah_var.h> 64 #include <netipsec/esp.h> 65 #include <netipsec/esp_var.h> 66 #include <netipsec/xform.h> 67 68 #ifdef INET6 69 #include <netinet6/ip6_var.h> 70 #include <netipsec/ipsec6.h> 71 #include <netinet6/ip6_ecn.h> 72 #endif 73 74 #include <netipsec/key.h> 75 #include <netipsec/key_debug.h> 76 77 #include <opencrypto/cryptodev.h> 78 #include <opencrypto/xform.h> 79 80 VNET_DEFINE(int, esp_enable) = 1; 81 VNET_PCPUSTAT_DEFINE(struct espstat, espstat); 82 VNET_PCPUSTAT_SYSINIT(espstat); 83 84 #ifdef VIMAGE 85 VNET_PCPUSTAT_SYSUNINIT(espstat); 86 #endif /* VIMAGE */ 87 88 SYSCTL_DECL(_net_inet_esp); 89 SYSCTL_INT(_net_inet_esp, OID_AUTO, esp_enable, 90 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(esp_enable), 0, ""); 91 SYSCTL_VNET_PCPUSTAT(_net_inet_esp, IPSECCTL_STATS, stats, 92 struct espstat, espstat, 93 "ESP statistics (struct espstat, netipsec/esp_var.h"); 94 95 static int esp_input_cb(struct cryptop *op); 96 static int esp_output_cb(struct cryptop *crp); 97 98 /* 99 * NB: this is public for use by the PF_KEY support. 100 * NB: if you add support here; be sure to add code to esp_attach below! 101 */ 102 struct enc_xform * 103 esp_algorithm_lookup(int alg) 104 { 105 if (alg >= ESP_ALG_MAX) 106 return NULL; 107 switch (alg) { 108 case SADB_EALG_DESCBC: 109 return &enc_xform_des; 110 case SADB_EALG_3DESCBC: 111 return &enc_xform_3des; 112 case SADB_X_EALG_AES: 113 return &enc_xform_rijndael128; 114 case SADB_X_EALG_BLOWFISHCBC: 115 return &enc_xform_blf; 116 case SADB_X_EALG_CAST128CBC: 117 return &enc_xform_cast5; 118 case SADB_X_EALG_SKIPJACK: 119 return &enc_xform_skipjack; 120 case SADB_EALG_NULL: 121 return &enc_xform_null; 122 case SADB_X_EALG_CAMELLIACBC: 123 return &enc_xform_camellia; 124 } 125 return NULL; 126 } 127 128 size_t 129 esp_hdrsiz(struct secasvar *sav) 130 { 131 size_t size; 132 133 if (sav != NULL) { 134 /*XXX not right for null algorithm--does it matter??*/ 135 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 136 ("SA with null xform")); 137 if (sav->flags & SADB_X_EXT_OLD) 138 size = sizeof (struct esp); 139 else 140 size = sizeof (struct newesp); 141 size += sav->tdb_encalgxform->blocksize + 9; 142 /*XXX need alg check???*/ 143 if (sav->tdb_authalgxform != NULL && sav->replay) 144 size += ah_hdrsiz(sav); 145 } else { 146 /* 147 * base header size 148 * + max iv length for CBC mode 149 * + max pad length 150 * + sizeof (pad length field) 151 * + sizeof (next header field) 152 * + max icv supported. 153 */ 154 size = sizeof (struct newesp) + EALG_MAX_BLOCK_LEN + 9 + 16; 155 } 156 return size; 157 } 158 159 /* 160 * esp_init() is called when an SPI is being set up. 161 */ 162 static int 163 esp_init(struct secasvar *sav, struct xformsw *xsp) 164 { 165 struct enc_xform *txform; 166 struct cryptoini cria, crie; 167 int keylen; 168 int error; 169 170 txform = esp_algorithm_lookup(sav->alg_enc); 171 if (txform == NULL) { 172 DPRINTF(("%s: unsupported encryption algorithm %d\n", 173 __func__, sav->alg_enc)); 174 return EINVAL; 175 } 176 if (sav->key_enc == NULL) { 177 DPRINTF(("%s: no encoding key for %s algorithm\n", 178 __func__, txform->name)); 179 return EINVAL; 180 } 181 if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) { 182 DPRINTF(("%s: 4-byte IV not supported with protocol\n", 183 __func__)); 184 return EINVAL; 185 } 186 keylen = _KEYLEN(sav->key_enc); 187 if (txform->minkey > keylen || keylen > txform->maxkey) { 188 DPRINTF(("%s: invalid key length %u, must be in the range " 189 "[%u..%u] for algorithm %s\n", __func__, 190 keylen, txform->minkey, txform->maxkey, 191 txform->name)); 192 return EINVAL; 193 } 194 195 /* 196 * NB: The null xform needs a non-zero blocksize to keep the 197 * crypto code happy but if we use it to set ivlen then 198 * the ESP header will be processed incorrectly. The 199 * compromise is to force it to zero here. 200 */ 201 sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize); 202 sav->iv = (caddr_t) malloc(sav->ivlen, M_XDATA, M_WAITOK); 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 ESPSTAT_INC(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 ESPSTAT_INC(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 ESPSTAT_INC(esps_replay); 347 m_freem(m); 348 return ENOBUFS; /*XXX*/ 349 } 350 351 /* Update the counters */ 352 ESPSTAT_ADD(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 ESPSTAT_INC(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 ESPSTAT_INC(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 /* 455 * ESP input callback from the crypto driver. 456 */ 457 static int 458 esp_input_cb(struct cryptop *crp) 459 { 460 u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN]; 461 int hlen, skip, protoff, error, alen; 462 struct mbuf *m; 463 struct cryptodesc *crd; 464 struct auth_hash *esph; 465 struct enc_xform *espx; 466 struct tdb_crypto *tc; 467 struct m_tag *mtag; 468 struct secasvar *sav; 469 struct secasindex *saidx; 470 caddr_t ptr; 471 472 crd = crp->crp_desc; 473 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!")); 474 475 tc = (struct tdb_crypto *) crp->crp_opaque; 476 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!")); 477 skip = tc->tc_skip; 478 protoff = tc->tc_protoff; 479 mtag = (struct m_tag *) tc->tc_ptr; 480 m = (struct mbuf *) crp->crp_buf; 481 482 sav = tc->tc_sav; 483 IPSEC_ASSERT(sav != NULL, ("null SA!")); 484 485 saidx = &sav->sah->saidx; 486 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 487 saidx->dst.sa.sa_family == AF_INET6, 488 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 489 490 esph = sav->tdb_authalgxform; 491 espx = sav->tdb_encalgxform; 492 493 /* Check for crypto errors */ 494 if (crp->crp_etype) { 495 /* Reset the session ID */ 496 if (sav->tdb_cryptoid != 0) 497 sav->tdb_cryptoid = crp->crp_sid; 498 499 if (crp->crp_etype == EAGAIN) 500 return (crypto_dispatch(crp)); 501 502 ESPSTAT_INC(esps_noxform); 503 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 504 error = crp->crp_etype; 505 goto bad; 506 } 507 508 /* Shouldn't happen... */ 509 if (m == NULL) { 510 ESPSTAT_INC(esps_crypto); 511 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 512 error = EINVAL; 513 goto bad; 514 } 515 ESPSTAT_INC(esps_hist[sav->alg_enc]); 516 517 /* If authentication was performed, check now. */ 518 if (esph != NULL) { 519 switch (esph->type) { 520 case CRYPTO_SHA2_256_HMAC: 521 case CRYPTO_SHA2_384_HMAC: 522 case CRYPTO_SHA2_512_HMAC: 523 alen = esph->hashsize/2; 524 break; 525 default: 526 alen = AH_HMAC_HASHLEN; 527 break; 528 } 529 /* 530 * If we have a tag, it means an IPsec-aware NIC did 531 * the verification for us. Otherwise we need to 532 * check the authentication calculation. 533 */ 534 AHSTAT_INC(ahs_hist[sav->alg_auth]); 535 if (mtag == NULL) { 536 /* Copy the authenticator from the packet */ 537 m_copydata(m, m->m_pkthdr.len - alen, 538 alen, aalg); 539 540 ptr = (caddr_t) (tc + 1); 541 542 /* Verify authenticator */ 543 if (bcmp(ptr, aalg, alen) != 0) { 544 DPRINTF(("%s: " 545 "authentication hash mismatch for packet in SA %s/%08lx\n", 546 __func__, 547 ipsec_address(&saidx->dst), 548 (u_long) ntohl(sav->spi))); 549 ESPSTAT_INC(esps_badauth); 550 error = EACCES; 551 goto bad; 552 } 553 } 554 555 /* Remove trailing authenticator */ 556 m_adj(m, -alen); 557 } 558 559 /* Release the crypto descriptors */ 560 free(tc, M_XDATA), tc = NULL; 561 crypto_freereq(crp), crp = NULL; 562 563 /* 564 * Packet is now decrypted. 565 */ 566 m->m_flags |= M_DECRYPTED; 567 568 /* 569 * Update replay sequence number, if appropriate. 570 */ 571 if (sav->replay) { 572 u_int32_t seq; 573 574 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 575 sizeof (seq), (caddr_t) &seq); 576 if (ipsec_updatereplay(ntohl(seq), sav)) { 577 DPRINTF(("%s: packet replay check for %s\n", __func__, 578 ipsec_logsastr(sav))); 579 ESPSTAT_INC(esps_replay); 580 error = ENOBUFS; 581 goto bad; 582 } 583 } 584 585 /* Determine the ESP header length */ 586 if (sav->flags & SADB_X_EXT_OLD) 587 hlen = sizeof (struct esp) + sav->ivlen; 588 else 589 hlen = sizeof (struct newesp) + sav->ivlen; 590 591 /* Remove the ESP header and IV from the mbuf. */ 592 error = m_striphdr(m, skip, hlen); 593 if (error) { 594 ESPSTAT_INC(esps_hdrops); 595 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 596 ipsec_address(&sav->sah->saidx.dst), 597 (u_long) ntohl(sav->spi))); 598 goto bad; 599 } 600 601 /* Save the last three bytes of decrypted data */ 602 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 603 604 /* Verify pad length */ 605 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 606 ESPSTAT_INC(esps_badilen); 607 DPRINTF(("%s: invalid padding length %d for %u byte packet " 608 "in SA %s/%08lx\n", __func__, 609 lastthree[1], m->m_pkthdr.len - skip, 610 ipsec_address(&sav->sah->saidx.dst), 611 (u_long) ntohl(sav->spi))); 612 error = EINVAL; 613 goto bad; 614 } 615 616 /* Verify correct decryption by checking the last padding bytes */ 617 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 618 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 619 ESPSTAT_INC(esps_badenc); 620 DPRINTF(("%s: decryption failed for packet in " 621 "SA %s/%08lx\n", __func__, 622 ipsec_address(&sav->sah->saidx.dst), 623 (u_long) ntohl(sav->spi))); 624 error = EINVAL; 625 goto bad; 626 } 627 } 628 629 /* Trim the mbuf chain to remove trailing authenticator and padding */ 630 m_adj(m, -(lastthree[1] + 2)); 631 632 /* Restore the Next Protocol field */ 633 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 634 635 switch (saidx->dst.sa.sa_family) { 636 #ifdef INET6 637 case AF_INET6: 638 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); 639 break; 640 #endif 641 #ifdef INET 642 case AF_INET: 643 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); 644 break; 645 #endif 646 default: 647 panic("%s: Unexpected address family: %d saidx=%p", __func__, 648 saidx->dst.sa.sa_family, saidx); 649 } 650 651 KEY_FREESAV(&sav); 652 return error; 653 bad: 654 if (sav) 655 KEY_FREESAV(&sav); 656 if (m != NULL) 657 m_freem(m); 658 if (tc != NULL) 659 free(tc, M_XDATA); 660 if (crp != NULL) 661 crypto_freereq(crp); 662 return error; 663 } 664 665 /* 666 * ESP output routine, called by ipsec[46]_process_packet(). 667 */ 668 static int 669 esp_output( 670 struct mbuf *m, 671 struct ipsecrequest *isr, 672 struct mbuf **mp, 673 int skip, 674 int protoff 675 ) 676 { 677 struct enc_xform *espx; 678 struct auth_hash *esph; 679 int hlen, rlen, padding, blks, alen, i, roff; 680 struct mbuf *mo = (struct mbuf *) NULL; 681 struct tdb_crypto *tc; 682 struct secasvar *sav; 683 struct secasindex *saidx; 684 unsigned char *pad; 685 u_int8_t prot; 686 int error, maxpacketsize; 687 688 struct cryptodesc *crde = NULL, *crda = NULL; 689 struct cryptop *crp; 690 691 sav = isr->sav; 692 IPSEC_ASSERT(sav != NULL, ("null SA")); 693 esph = sav->tdb_authalgxform; 694 espx = sav->tdb_encalgxform; 695 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 696 697 if (sav->flags & SADB_X_EXT_OLD) 698 hlen = sizeof (struct esp) + sav->ivlen; 699 else 700 hlen = sizeof (struct newesp) + sav->ivlen; 701 702 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 703 /* 704 * NB: The null encoding transform has a blocksize of 4 705 * so that headers are properly aligned. 706 */ 707 blks = espx->blocksize; /* IV blocksize */ 708 709 /* XXX clamp padding length a la KAME??? */ 710 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 711 712 if (esph) 713 switch (esph->type) { 714 case CRYPTO_SHA2_256_HMAC: 715 case CRYPTO_SHA2_384_HMAC: 716 case CRYPTO_SHA2_512_HMAC: 717 alen = esph->hashsize/2; 718 break; 719 default: 720 alen = AH_HMAC_HASHLEN; 721 break; 722 } 723 else 724 alen = 0; 725 726 ESPSTAT_INC(esps_output); 727 728 saidx = &sav->sah->saidx; 729 /* Check for maximum packet size violations. */ 730 switch (saidx->dst.sa.sa_family) { 731 #ifdef INET 732 case AF_INET: 733 maxpacketsize = IP_MAXPACKET; 734 break; 735 #endif /* INET */ 736 #ifdef INET6 737 case AF_INET6: 738 maxpacketsize = IPV6_MAXPACKET; 739 break; 740 #endif /* INET6 */ 741 default: 742 DPRINTF(("%s: unknown/unsupported protocol " 743 "family %d, SA %s/%08lx\n", __func__, 744 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst), 745 (u_long) ntohl(sav->spi))); 746 ESPSTAT_INC(esps_nopf); 747 error = EPFNOSUPPORT; 748 goto bad; 749 } 750 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 751 DPRINTF(("%s: packet in SA %s/%08lx got too big " 752 "(len %u, max len %u)\n", __func__, 753 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi), 754 skip + hlen + rlen + padding + alen, maxpacketsize)); 755 ESPSTAT_INC(esps_toobig); 756 error = EMSGSIZE; 757 goto bad; 758 } 759 760 /* Update the counters. */ 761 ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip); 762 763 m = m_unshare(m, M_NOWAIT); 764 if (m == NULL) { 765 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 766 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 767 ESPSTAT_INC(esps_hdrops); 768 error = ENOBUFS; 769 goto bad; 770 } 771 772 /* Inject ESP header. */ 773 mo = m_makespace(m, skip, hlen, &roff); 774 if (mo == NULL) { 775 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 776 __func__, hlen, ipsec_address(&saidx->dst), 777 (u_long) ntohl(sav->spi))); 778 ESPSTAT_INC(esps_hdrops); /* XXX diffs from openbsd */ 779 error = ENOBUFS; 780 goto bad; 781 } 782 783 /* Initialize ESP header. */ 784 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t)); 785 if (sav->replay) { 786 u_int32_t replay; 787 788 #ifdef REGRESSION 789 /* Emulate replay attack when ipsec_replay is TRUE. */ 790 if (!V_ipsec_replay) 791 #endif 792 sav->replay->count++; 793 replay = htonl(sav->replay->count); 794 bcopy((caddr_t) &replay, 795 mtod(mo, caddr_t) + roff + sizeof(u_int32_t), 796 sizeof(u_int32_t)); 797 } 798 799 /* 800 * Add padding -- better to do it ourselves than use the crypto engine, 801 * although if/when we support compression, we'd have to do that. 802 */ 803 pad = (u_char *) m_pad(m, padding + alen); 804 if (pad == NULL) { 805 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 806 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 807 m = NULL; /* NB: free'd by m_pad */ 808 error = ENOBUFS; 809 goto bad; 810 } 811 812 /* 813 * Add padding: random, zero, or self-describing. 814 * XXX catch unexpected setting 815 */ 816 switch (sav->flags & SADB_X_EXT_PMASK) { 817 case SADB_X_EXT_PRAND: 818 (void) read_random(pad, padding - 2); 819 break; 820 case SADB_X_EXT_PZERO: 821 bzero(pad, padding - 2); 822 break; 823 case SADB_X_EXT_PSEQ: 824 for (i = 0; i < padding - 2; i++) 825 pad[i] = i+1; 826 break; 827 } 828 829 /* Fix padding length and Next Protocol in padding itself. */ 830 pad[padding - 2] = padding - 2; 831 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 832 833 /* Fix Next Protocol in IPv4/IPv6 header. */ 834 prot = IPPROTO_ESP; 835 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 836 837 /* Get crypto descriptors. */ 838 crp = crypto_getreq(esph && espx ? 2 : 1); 839 if (crp == NULL) { 840 DPRINTF(("%s: failed to acquire crypto descriptors\n", 841 __func__)); 842 ESPSTAT_INC(esps_crypto); 843 error = ENOBUFS; 844 goto bad; 845 } 846 847 if (espx) { 848 crde = crp->crp_desc; 849 crda = crde->crd_next; 850 851 /* Encryption descriptor. */ 852 crde->crd_skip = skip + hlen; 853 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 854 crde->crd_flags = CRD_F_ENCRYPT; 855 crde->crd_inject = skip + hlen - sav->ivlen; 856 857 /* Encryption operation. */ 858 crde->crd_alg = espx->type; 859 crde->crd_key = sav->key_enc->key_data; 860 crde->crd_klen = _KEYBITS(sav->key_enc); 861 /* XXX Rounds ? */ 862 } else 863 crda = crp->crp_desc; 864 865 /* IPsec-specific opaque crypto info. */ 866 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 867 M_XDATA, M_NOWAIT|M_ZERO); 868 if (tc == NULL) { 869 crypto_freereq(crp); 870 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 871 ESPSTAT_INC(esps_crypto); 872 error = ENOBUFS; 873 goto bad; 874 } 875 876 /* Callback parameters */ 877 tc->tc_isr = isr; 878 KEY_ADDREFSA(sav); 879 tc->tc_sav = sav; 880 tc->tc_spi = sav->spi; 881 tc->tc_dst = saidx->dst; 882 tc->tc_proto = saidx->proto; 883 884 /* Crypto operation descriptor. */ 885 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 886 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 887 crp->crp_buf = (caddr_t) m; 888 crp->crp_callback = esp_output_cb; 889 crp->crp_opaque = (caddr_t) tc; 890 crp->crp_sid = sav->tdb_cryptoid; 891 892 if (esph) { 893 /* Authentication descriptor. */ 894 crda->crd_skip = skip; 895 crda->crd_len = m->m_pkthdr.len - (skip + alen); 896 crda->crd_inject = m->m_pkthdr.len - alen; 897 898 /* Authentication operation. */ 899 crda->crd_alg = esph->type; 900 crda->crd_key = sav->key_auth->key_data; 901 crda->crd_klen = _KEYBITS(sav->key_auth); 902 } 903 904 return crypto_dispatch(crp); 905 bad: 906 if (m) 907 m_freem(m); 908 return (error); 909 } 910 911 /* 912 * ESP output callback from the crypto driver. 913 */ 914 static int 915 esp_output_cb(struct cryptop *crp) 916 { 917 struct tdb_crypto *tc; 918 struct ipsecrequest *isr; 919 struct secasvar *sav; 920 struct mbuf *m; 921 int error; 922 923 tc = (struct tdb_crypto *) crp->crp_opaque; 924 IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); 925 m = (struct mbuf *) crp->crp_buf; 926 927 isr = tc->tc_isr; 928 IPSECREQUEST_LOCK(isr); 929 sav = tc->tc_sav; 930 /* With the isr lock released SA pointer can be updated. */ 931 if (sav != isr->sav) { 932 ESPSTAT_INC(esps_notdb); 933 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 934 __func__, ipsec_address(&tc->tc_dst), 935 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 936 error = ENOBUFS; /*XXX*/ 937 goto bad; 938 } 939 940 /* Check for crypto errors. */ 941 if (crp->crp_etype) { 942 /* Reset session ID. */ 943 if (sav->tdb_cryptoid != 0) 944 sav->tdb_cryptoid = crp->crp_sid; 945 946 if (crp->crp_etype == EAGAIN) { 947 IPSECREQUEST_UNLOCK(isr); 948 return (crypto_dispatch(crp)); 949 } 950 951 ESPSTAT_INC(esps_noxform); 952 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 953 error = crp->crp_etype; 954 goto bad; 955 } 956 957 /* Shouldn't happen... */ 958 if (m == NULL) { 959 ESPSTAT_INC(esps_crypto); 960 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 961 error = EINVAL; 962 goto bad; 963 } 964 ESPSTAT_INC(esps_hist[sav->alg_enc]); 965 if (sav->tdb_authalgxform != NULL) 966 AHSTAT_INC(ahs_hist[sav->alg_auth]); 967 968 /* Release crypto descriptors. */ 969 free(tc, M_XDATA); 970 crypto_freereq(crp); 971 972 #ifdef REGRESSION 973 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 974 if (V_ipsec_integrity) { 975 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN]; 976 struct auth_hash *esph; 977 978 /* 979 * Corrupt HMAC if we want to test integrity verification of 980 * the other side. 981 */ 982 esph = sav->tdb_authalgxform; 983 if (esph != NULL) { 984 int alen; 985 986 switch (esph->type) { 987 case CRYPTO_SHA2_256_HMAC: 988 case CRYPTO_SHA2_384_HMAC: 989 case CRYPTO_SHA2_512_HMAC: 990 alen = esph->hashsize/2; 991 break; 992 default: 993 alen = AH_HMAC_HASHLEN; 994 break; 995 } 996 m_copyback(m, m->m_pkthdr.len - alen, 997 alen, ipseczeroes); 998 } 999 } 1000 #endif 1001 1002 /* NB: m is reclaimed by ipsec_process_done. */ 1003 error = ipsec_process_done(m, isr); 1004 KEY_FREESAV(&sav); 1005 IPSECREQUEST_UNLOCK(isr); 1006 return error; 1007 bad: 1008 if (sav) 1009 KEY_FREESAV(&sav); 1010 IPSECREQUEST_UNLOCK(isr); 1011 if (m) 1012 m_freem(m); 1013 free(tc, M_XDATA); 1014 crypto_freereq(crp); 1015 return error; 1016 } 1017 1018 static struct xformsw esp_xformsw = { 1019 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 1020 esp_init, esp_zeroize, esp_input, 1021 esp_output 1022 }; 1023 1024 static void 1025 esp_attach(void) 1026 { 1027 1028 xform_register(&esp_xformsw); 1029 } 1030 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL); 1031