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_crypto *tc; 274 int plen, alen, hlen; 275 struct newesp *esp; 276 struct cryptodesc *crde; 277 struct cryptop *crp; 278 279 IPSEC_ASSERT(sav != NULL, ("null SA")); 280 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); 281 282 alen = 0; 283 /* Valid IP Packet length ? */ 284 if ( (skip&3) || (m->m_pkthdr.len&3) ){ 285 DPRINTF(("%s: misaligned packet, skip %u pkt len %u", 286 __func__, skip, m->m_pkthdr.len)); 287 ESPSTAT_INC(esps_badilen); 288 m_freem(m); 289 return EINVAL; 290 } 291 292 /* XXX don't pullup, just copy header */ 293 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 294 295 esph = sav->tdb_authalgxform; 296 espx = sav->tdb_encalgxform; 297 298 /* Determine the ESP header length */ 299 if (sav->flags & SADB_X_EXT_OLD) 300 hlen = sizeof (struct esp) + sav->ivlen; 301 else 302 hlen = sizeof (struct newesp) + sav->ivlen; 303 /* Authenticator hash size */ 304 if (esph != NULL) { 305 switch (esph->type) { 306 case CRYPTO_SHA2_256_HMAC: 307 case CRYPTO_SHA2_384_HMAC: 308 case CRYPTO_SHA2_512_HMAC: 309 alen = esph->hashsize/2; 310 break; 311 default: 312 alen = AH_HMAC_HASHLEN; 313 break; 314 } 315 } 316 317 /* 318 * Verify payload length is multiple of encryption algorithm 319 * block size. 320 * 321 * NB: This works for the null algorithm because the blocksize 322 * is 4 and all packets must be 4-byte aligned regardless 323 * of the algorithm. 324 */ 325 plen = m->m_pkthdr.len - (skip + hlen + alen); 326 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 327 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 328 " SA %s/%08lx\n", __func__, 329 plen, espx->blocksize, 330 ipsec_address(&sav->sah->saidx.dst), 331 (u_long) ntohl(sav->spi))); 332 ESPSTAT_INC(esps_badilen); 333 m_freem(m); 334 return EINVAL; 335 } 336 337 /* 338 * Check sequence number. 339 */ 340 if (esph != NULL && sav->replay != NULL && 341 !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) { 342 DPRINTF(("%s: packet replay check for %s\n", __func__, 343 ipsec_logsastr(sav))); /*XXX*/ 344 ESPSTAT_INC(esps_replay); 345 m_freem(m); 346 return ENOBUFS; /*XXX*/ 347 } 348 349 /* Update the counters */ 350 ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen)); 351 352 /* Get crypto descriptors */ 353 crp = crypto_getreq(esph && espx ? 2 : 1); 354 if (crp == NULL) { 355 DPRINTF(("%s: failed to acquire crypto descriptors\n", 356 __func__)); 357 ESPSTAT_INC(esps_crypto); 358 m_freem(m); 359 return ENOBUFS; 360 } 361 362 /* Get IPsec-specific opaque pointer */ 363 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen, 364 M_XDATA, M_NOWAIT | M_ZERO); 365 if (tc == NULL) { 366 crypto_freereq(crp); 367 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 368 ESPSTAT_INC(esps_crypto); 369 m_freem(m); 370 return ENOBUFS; 371 } 372 373 if (esph != NULL) { 374 struct cryptodesc *crda = crp->crp_desc; 375 376 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor")); 377 378 /* Authentication descriptor */ 379 crda->crd_skip = skip; 380 crda->crd_len = m->m_pkthdr.len - (skip + alen); 381 crda->crd_inject = m->m_pkthdr.len - alen; 382 383 crda->crd_alg = esph->type; 384 crda->crd_key = sav->key_auth->key_data; 385 crda->crd_klen = _KEYBITS(sav->key_auth); 386 387 /* Copy the authenticator */ 388 m_copydata(m, m->m_pkthdr.len - alen, alen, 389 (caddr_t) (tc + 1)); 390 391 /* Chain authentication request */ 392 crde = crda->crd_next; 393 } else { 394 crde = crp->crp_desc; 395 } 396 397 /* Crypto operation descriptor */ 398 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 399 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 400 crp->crp_buf = (caddr_t) m; 401 crp->crp_callback = esp_input_cb; 402 crp->crp_sid = sav->tdb_cryptoid; 403 crp->crp_opaque = (caddr_t) tc; 404 405 /* These are passed as-is to the callback */ 406 tc->tc_spi = sav->spi; 407 tc->tc_dst = sav->sah->saidx.dst; 408 tc->tc_proto = sav->sah->saidx.proto; 409 tc->tc_protoff = protoff; 410 tc->tc_skip = skip; 411 KEY_ADDREFSA(sav); 412 tc->tc_sav = sav; 413 414 /* Decryption descriptor */ 415 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor")); 416 crde->crd_skip = skip + hlen; 417 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 418 crde->crd_inject = skip + hlen - sav->ivlen; 419 420 crde->crd_alg = espx->type; 421 crde->crd_key = sav->key_enc->key_data; 422 crde->crd_klen = _KEYBITS(sav->key_enc); 423 /* XXX Rounds ? */ 424 425 return (crypto_dispatch(crp)); 426 } 427 428 /* 429 * ESP input callback from the crypto driver. 430 */ 431 static int 432 esp_input_cb(struct cryptop *crp) 433 { 434 u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN]; 435 int hlen, skip, protoff, error, alen; 436 struct mbuf *m; 437 struct cryptodesc *crd; 438 struct auth_hash *esph; 439 struct enc_xform *espx; 440 struct tdb_crypto *tc; 441 struct secasvar *sav; 442 struct secasindex *saidx; 443 caddr_t ptr; 444 445 crd = crp->crp_desc; 446 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!")); 447 448 tc = (struct tdb_crypto *) crp->crp_opaque; 449 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!")); 450 skip = tc->tc_skip; 451 protoff = tc->tc_protoff; 452 m = (struct mbuf *) crp->crp_buf; 453 454 sav = tc->tc_sav; 455 IPSEC_ASSERT(sav != NULL, ("null SA!")); 456 457 saidx = &sav->sah->saidx; 458 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 459 saidx->dst.sa.sa_family == AF_INET6, 460 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 461 462 esph = sav->tdb_authalgxform; 463 espx = sav->tdb_encalgxform; 464 465 /* Check for crypto errors */ 466 if (crp->crp_etype) { 467 /* Reset the session ID */ 468 if (sav->tdb_cryptoid != 0) 469 sav->tdb_cryptoid = crp->crp_sid; 470 471 if (crp->crp_etype == EAGAIN) 472 return (crypto_dispatch(crp)); 473 474 ESPSTAT_INC(esps_noxform); 475 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 476 error = crp->crp_etype; 477 goto bad; 478 } 479 480 /* Shouldn't happen... */ 481 if (m == NULL) { 482 ESPSTAT_INC(esps_crypto); 483 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 484 error = EINVAL; 485 goto bad; 486 } 487 ESPSTAT_INC(esps_hist[sav->alg_enc]); 488 489 /* If authentication was performed, check now. */ 490 if (esph != NULL) { 491 switch (esph->type) { 492 case CRYPTO_SHA2_256_HMAC: 493 case CRYPTO_SHA2_384_HMAC: 494 case CRYPTO_SHA2_512_HMAC: 495 alen = esph->hashsize/2; 496 break; 497 default: 498 alen = AH_HMAC_HASHLEN; 499 break; 500 } 501 AHSTAT_INC(ahs_hist[sav->alg_auth]); 502 /* Copy the authenticator from the packet */ 503 m_copydata(m, m->m_pkthdr.len - alen, alen, aalg); 504 ptr = (caddr_t) (tc + 1); 505 506 /* Verify authenticator */ 507 if (bcmp(ptr, aalg, alen) != 0) { 508 DPRINTF(("%s: authentication hash mismatch for " 509 "packet in SA %s/%08lx\n", __func__, 510 ipsec_address(&saidx->dst), 511 (u_long) ntohl(sav->spi))); 512 ESPSTAT_INC(esps_badauth); 513 error = EACCES; 514 goto bad; 515 } 516 517 /* Remove trailing authenticator */ 518 m_adj(m, -alen); 519 } 520 521 /* Release the crypto descriptors */ 522 free(tc, M_XDATA), tc = NULL; 523 crypto_freereq(crp), crp = NULL; 524 525 /* 526 * Packet is now decrypted. 527 */ 528 m->m_flags |= M_DECRYPTED; 529 530 /* 531 * Update replay sequence number, if appropriate. 532 */ 533 if (sav->replay) { 534 u_int32_t seq; 535 536 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 537 sizeof (seq), (caddr_t) &seq); 538 if (ipsec_updatereplay(ntohl(seq), sav)) { 539 DPRINTF(("%s: packet replay check for %s\n", __func__, 540 ipsec_logsastr(sav))); 541 ESPSTAT_INC(esps_replay); 542 error = ENOBUFS; 543 goto bad; 544 } 545 } 546 547 /* Determine the ESP header length */ 548 if (sav->flags & SADB_X_EXT_OLD) 549 hlen = sizeof (struct esp) + sav->ivlen; 550 else 551 hlen = sizeof (struct newesp) + sav->ivlen; 552 553 /* Remove the ESP header and IV from the mbuf. */ 554 error = m_striphdr(m, skip, hlen); 555 if (error) { 556 ESPSTAT_INC(esps_hdrops); 557 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 558 ipsec_address(&sav->sah->saidx.dst), 559 (u_long) ntohl(sav->spi))); 560 goto bad; 561 } 562 563 /* Save the last three bytes of decrypted data */ 564 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 565 566 /* Verify pad length */ 567 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 568 ESPSTAT_INC(esps_badilen); 569 DPRINTF(("%s: invalid padding length %d for %u byte packet " 570 "in SA %s/%08lx\n", __func__, 571 lastthree[1], m->m_pkthdr.len - skip, 572 ipsec_address(&sav->sah->saidx.dst), 573 (u_long) ntohl(sav->spi))); 574 error = EINVAL; 575 goto bad; 576 } 577 578 /* Verify correct decryption by checking the last padding bytes */ 579 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 580 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 581 ESPSTAT_INC(esps_badenc); 582 DPRINTF(("%s: decryption failed for packet in " 583 "SA %s/%08lx\n", __func__, 584 ipsec_address(&sav->sah->saidx.dst), 585 (u_long) ntohl(sav->spi))); 586 error = EINVAL; 587 goto bad; 588 } 589 } 590 591 /* Trim the mbuf chain to remove trailing authenticator and padding */ 592 m_adj(m, -(lastthree[1] + 2)); 593 594 /* Restore the Next Protocol field */ 595 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 596 597 switch (saidx->dst.sa.sa_family) { 598 #ifdef INET6 599 case AF_INET6: 600 error = ipsec6_common_input_cb(m, sav, skip, protoff); 601 break; 602 #endif 603 #ifdef INET 604 case AF_INET: 605 error = ipsec4_common_input_cb(m, sav, skip, protoff); 606 break; 607 #endif 608 default: 609 panic("%s: Unexpected address family: %d saidx=%p", __func__, 610 saidx->dst.sa.sa_family, saidx); 611 } 612 613 KEY_FREESAV(&sav); 614 return error; 615 bad: 616 if (sav) 617 KEY_FREESAV(&sav); 618 if (m != NULL) 619 m_freem(m); 620 if (tc != NULL) 621 free(tc, M_XDATA); 622 if (crp != NULL) 623 crypto_freereq(crp); 624 return error; 625 } 626 627 /* 628 * ESP output routine, called by ipsec[46]_process_packet(). 629 */ 630 static int 631 esp_output( 632 struct mbuf *m, 633 struct ipsecrequest *isr, 634 struct mbuf **mp, 635 int skip, 636 int protoff 637 ) 638 { 639 struct enc_xform *espx; 640 struct auth_hash *esph; 641 int hlen, rlen, padding, blks, alen, i, roff; 642 struct mbuf *mo = (struct mbuf *) NULL; 643 struct tdb_crypto *tc; 644 struct secasvar *sav; 645 struct secasindex *saidx; 646 unsigned char *pad; 647 u_int8_t prot; 648 int error, maxpacketsize; 649 650 struct cryptodesc *crde = NULL, *crda = NULL; 651 struct cryptop *crp; 652 653 sav = isr->sav; 654 IPSEC_ASSERT(sav != NULL, ("null SA")); 655 esph = sav->tdb_authalgxform; 656 espx = sav->tdb_encalgxform; 657 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 658 659 if (sav->flags & SADB_X_EXT_OLD) 660 hlen = sizeof (struct esp) + sav->ivlen; 661 else 662 hlen = sizeof (struct newesp) + sav->ivlen; 663 664 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 665 /* 666 * NB: The null encoding transform has a blocksize of 4 667 * so that headers are properly aligned. 668 */ 669 blks = espx->blocksize; /* IV blocksize */ 670 671 /* XXX clamp padding length a la KAME??? */ 672 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 673 674 if (esph) 675 switch (esph->type) { 676 case CRYPTO_SHA2_256_HMAC: 677 case CRYPTO_SHA2_384_HMAC: 678 case CRYPTO_SHA2_512_HMAC: 679 alen = esph->hashsize/2; 680 break; 681 default: 682 alen = AH_HMAC_HASHLEN; 683 break; 684 } 685 else 686 alen = 0; 687 688 ESPSTAT_INC(esps_output); 689 690 saidx = &sav->sah->saidx; 691 /* Check for maximum packet size violations. */ 692 switch (saidx->dst.sa.sa_family) { 693 #ifdef INET 694 case AF_INET: 695 maxpacketsize = IP_MAXPACKET; 696 break; 697 #endif /* INET */ 698 #ifdef INET6 699 case AF_INET6: 700 maxpacketsize = IPV6_MAXPACKET; 701 break; 702 #endif /* INET6 */ 703 default: 704 DPRINTF(("%s: unknown/unsupported protocol " 705 "family %d, SA %s/%08lx\n", __func__, 706 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst), 707 (u_long) ntohl(sav->spi))); 708 ESPSTAT_INC(esps_nopf); 709 error = EPFNOSUPPORT; 710 goto bad; 711 } 712 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 713 DPRINTF(("%s: packet in SA %s/%08lx got too big " 714 "(len %u, max len %u)\n", __func__, 715 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi), 716 skip + hlen + rlen + padding + alen, maxpacketsize)); 717 ESPSTAT_INC(esps_toobig); 718 error = EMSGSIZE; 719 goto bad; 720 } 721 722 /* Update the counters. */ 723 ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip); 724 725 m = m_unshare(m, M_NOWAIT); 726 if (m == NULL) { 727 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 728 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 729 ESPSTAT_INC(esps_hdrops); 730 error = ENOBUFS; 731 goto bad; 732 } 733 734 /* Inject ESP header. */ 735 mo = m_makespace(m, skip, hlen, &roff); 736 if (mo == NULL) { 737 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 738 __func__, hlen, ipsec_address(&saidx->dst), 739 (u_long) ntohl(sav->spi))); 740 ESPSTAT_INC(esps_hdrops); /* XXX diffs from openbsd */ 741 error = ENOBUFS; 742 goto bad; 743 } 744 745 /* Initialize ESP header. */ 746 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t)); 747 if (sav->replay) { 748 u_int32_t replay; 749 750 #ifdef REGRESSION 751 /* Emulate replay attack when ipsec_replay is TRUE. */ 752 if (!V_ipsec_replay) 753 #endif 754 sav->replay->count++; 755 replay = htonl(sav->replay->count); 756 bcopy((caddr_t) &replay, 757 mtod(mo, caddr_t) + roff + sizeof(u_int32_t), 758 sizeof(u_int32_t)); 759 } 760 761 /* 762 * Add padding -- better to do it ourselves than use the crypto engine, 763 * although if/when we support compression, we'd have to do that. 764 */ 765 pad = (u_char *) m_pad(m, padding + alen); 766 if (pad == NULL) { 767 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 768 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 769 m = NULL; /* NB: free'd by m_pad */ 770 error = ENOBUFS; 771 goto bad; 772 } 773 774 /* 775 * Add padding: random, zero, or self-describing. 776 * XXX catch unexpected setting 777 */ 778 switch (sav->flags & SADB_X_EXT_PMASK) { 779 case SADB_X_EXT_PRAND: 780 (void) read_random(pad, padding - 2); 781 break; 782 case SADB_X_EXT_PZERO: 783 bzero(pad, padding - 2); 784 break; 785 case SADB_X_EXT_PSEQ: 786 for (i = 0; i < padding - 2; i++) 787 pad[i] = i+1; 788 break; 789 } 790 791 /* Fix padding length and Next Protocol in padding itself. */ 792 pad[padding - 2] = padding - 2; 793 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 794 795 /* Fix Next Protocol in IPv4/IPv6 header. */ 796 prot = IPPROTO_ESP; 797 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 798 799 /* Get crypto descriptors. */ 800 crp = crypto_getreq(esph && espx ? 2 : 1); 801 if (crp == NULL) { 802 DPRINTF(("%s: failed to acquire crypto descriptors\n", 803 __func__)); 804 ESPSTAT_INC(esps_crypto); 805 error = ENOBUFS; 806 goto bad; 807 } 808 809 if (espx) { 810 crde = crp->crp_desc; 811 crda = crde->crd_next; 812 813 /* Encryption descriptor. */ 814 crde->crd_skip = skip + hlen; 815 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 816 crde->crd_flags = CRD_F_ENCRYPT; 817 crde->crd_inject = skip + hlen - sav->ivlen; 818 819 /* Encryption operation. */ 820 crde->crd_alg = espx->type; 821 crde->crd_key = sav->key_enc->key_data; 822 crde->crd_klen = _KEYBITS(sav->key_enc); 823 /* XXX Rounds ? */ 824 } else 825 crda = crp->crp_desc; 826 827 /* IPsec-specific opaque crypto info. */ 828 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 829 M_XDATA, M_NOWAIT|M_ZERO); 830 if (tc == NULL) { 831 crypto_freereq(crp); 832 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 833 ESPSTAT_INC(esps_crypto); 834 error = ENOBUFS; 835 goto bad; 836 } 837 838 /* Callback parameters */ 839 tc->tc_isr = isr; 840 KEY_ADDREFSA(sav); 841 tc->tc_sav = sav; 842 tc->tc_spi = sav->spi; 843 tc->tc_dst = saidx->dst; 844 tc->tc_proto = saidx->proto; 845 846 /* Crypto operation descriptor. */ 847 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 848 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 849 crp->crp_buf = (caddr_t) m; 850 crp->crp_callback = esp_output_cb; 851 crp->crp_opaque = (caddr_t) tc; 852 crp->crp_sid = sav->tdb_cryptoid; 853 854 if (esph) { 855 /* Authentication descriptor. */ 856 crda->crd_skip = skip; 857 crda->crd_len = m->m_pkthdr.len - (skip + alen); 858 crda->crd_inject = m->m_pkthdr.len - alen; 859 860 /* Authentication operation. */ 861 crda->crd_alg = esph->type; 862 crda->crd_key = sav->key_auth->key_data; 863 crda->crd_klen = _KEYBITS(sav->key_auth); 864 } 865 866 return crypto_dispatch(crp); 867 bad: 868 if (m) 869 m_freem(m); 870 return (error); 871 } 872 873 /* 874 * ESP output callback from the crypto driver. 875 */ 876 static int 877 esp_output_cb(struct cryptop *crp) 878 { 879 struct tdb_crypto *tc; 880 struct ipsecrequest *isr; 881 struct secasvar *sav; 882 struct mbuf *m; 883 int error; 884 885 tc = (struct tdb_crypto *) crp->crp_opaque; 886 IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); 887 m = (struct mbuf *) crp->crp_buf; 888 889 isr = tc->tc_isr; 890 IPSECREQUEST_LOCK(isr); 891 sav = tc->tc_sav; 892 /* With the isr lock released SA pointer can be updated. */ 893 if (sav != isr->sav) { 894 ESPSTAT_INC(esps_notdb); 895 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 896 __func__, ipsec_address(&tc->tc_dst), 897 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 898 error = ENOBUFS; /*XXX*/ 899 goto bad; 900 } 901 902 /* Check for crypto errors. */ 903 if (crp->crp_etype) { 904 /* Reset session ID. */ 905 if (sav->tdb_cryptoid != 0) 906 sav->tdb_cryptoid = crp->crp_sid; 907 908 if (crp->crp_etype == EAGAIN) { 909 IPSECREQUEST_UNLOCK(isr); 910 return (crypto_dispatch(crp)); 911 } 912 913 ESPSTAT_INC(esps_noxform); 914 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 915 error = crp->crp_etype; 916 goto bad; 917 } 918 919 /* Shouldn't happen... */ 920 if (m == NULL) { 921 ESPSTAT_INC(esps_crypto); 922 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 923 error = EINVAL; 924 goto bad; 925 } 926 ESPSTAT_INC(esps_hist[sav->alg_enc]); 927 if (sav->tdb_authalgxform != NULL) 928 AHSTAT_INC(ahs_hist[sav->alg_auth]); 929 930 /* Release crypto descriptors. */ 931 free(tc, M_XDATA); 932 crypto_freereq(crp); 933 934 #ifdef REGRESSION 935 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 936 if (V_ipsec_integrity) { 937 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN]; 938 struct auth_hash *esph; 939 940 /* 941 * Corrupt HMAC if we want to test integrity verification of 942 * the other side. 943 */ 944 esph = sav->tdb_authalgxform; 945 if (esph != NULL) { 946 int alen; 947 948 switch (esph->type) { 949 case CRYPTO_SHA2_256_HMAC: 950 case CRYPTO_SHA2_384_HMAC: 951 case CRYPTO_SHA2_512_HMAC: 952 alen = esph->hashsize/2; 953 break; 954 default: 955 alen = AH_HMAC_HASHLEN; 956 break; 957 } 958 m_copyback(m, m->m_pkthdr.len - alen, 959 alen, ipseczeroes); 960 } 961 } 962 #endif 963 964 /* NB: m is reclaimed by ipsec_process_done. */ 965 error = ipsec_process_done(m, isr); 966 KEY_FREESAV(&sav); 967 IPSECREQUEST_UNLOCK(isr); 968 return error; 969 bad: 970 if (sav) 971 KEY_FREESAV(&sav); 972 IPSECREQUEST_UNLOCK(isr); 973 if (m) 974 m_freem(m); 975 free(tc, M_XDATA); 976 crypto_freereq(crp); 977 return error; 978 } 979 980 static struct xformsw esp_xformsw = { 981 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 982 esp_init, esp_zeroize, esp_input, 983 esp_output 984 }; 985 986 static void 987 esp_attach(void) 988 { 989 990 xform_register(&esp_xformsw); 991 } 992 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL); 993