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 char buf[128]; 272 struct auth_hash *esph; 273 struct enc_xform *espx; 274 struct tdb_crypto *tc; 275 int plen, alen, hlen; 276 struct newesp *esp; 277 struct cryptodesc *crde; 278 struct cryptop *crp; 279 280 IPSEC_ASSERT(sav != NULL, ("null SA")); 281 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); 282 283 alen = 0; 284 /* Valid IP Packet length ? */ 285 if ( (skip&3) || (m->m_pkthdr.len&3) ){ 286 DPRINTF(("%s: misaligned packet, skip %u pkt len %u", 287 __func__, skip, m->m_pkthdr.len)); 288 ESPSTAT_INC(esps_badilen); 289 m_freem(m); 290 return EINVAL; 291 } 292 293 /* XXX don't pullup, just copy header */ 294 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 295 296 esph = sav->tdb_authalgxform; 297 espx = sav->tdb_encalgxform; 298 299 /* Determine the ESP header length */ 300 if (sav->flags & SADB_X_EXT_OLD) 301 hlen = sizeof (struct esp) + sav->ivlen; 302 else 303 hlen = sizeof (struct newesp) + sav->ivlen; 304 /* Authenticator hash size */ 305 if (esph != NULL) { 306 switch (esph->type) { 307 case CRYPTO_SHA2_256_HMAC: 308 case CRYPTO_SHA2_384_HMAC: 309 case CRYPTO_SHA2_512_HMAC: 310 alen = esph->hashsize/2; 311 break; 312 default: 313 alen = AH_HMAC_HASHLEN; 314 break; 315 } 316 } 317 318 /* 319 * Verify payload length is multiple of encryption algorithm 320 * block size. 321 * 322 * NB: This works for the null algorithm because the blocksize 323 * is 4 and all packets must be 4-byte aligned regardless 324 * of the algorithm. 325 */ 326 plen = m->m_pkthdr.len - (skip + hlen + alen); 327 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 328 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 329 " SA %s/%08lx\n", __func__, 330 plen, espx->blocksize, ipsec_address(&sav->sah->saidx.dst, 331 buf, sizeof(buf)), (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, buf, sizeof(buf)))); /*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 char buf[128]; 435 u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN]; 436 int hlen, skip, protoff, error, alen; 437 struct mbuf *m; 438 struct cryptodesc *crd; 439 struct auth_hash *esph; 440 struct enc_xform *espx; 441 struct tdb_crypto *tc; 442 struct secasvar *sav; 443 struct secasindex *saidx; 444 caddr_t ptr; 445 446 crd = crp->crp_desc; 447 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!")); 448 449 tc = (struct tdb_crypto *) crp->crp_opaque; 450 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!")); 451 skip = tc->tc_skip; 452 protoff = tc->tc_protoff; 453 m = (struct mbuf *) crp->crp_buf; 454 455 sav = tc->tc_sav; 456 IPSEC_ASSERT(sav != NULL, ("null SA!")); 457 458 saidx = &sav->sah->saidx; 459 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 460 saidx->dst.sa.sa_family == AF_INET6, 461 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 462 463 esph = sav->tdb_authalgxform; 464 espx = sav->tdb_encalgxform; 465 466 /* Check for crypto errors */ 467 if (crp->crp_etype) { 468 /* Reset the session ID */ 469 if (sav->tdb_cryptoid != 0) 470 sav->tdb_cryptoid = crp->crp_sid; 471 472 if (crp->crp_etype == EAGAIN) 473 return (crypto_dispatch(crp)); 474 475 ESPSTAT_INC(esps_noxform); 476 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 477 error = crp->crp_etype; 478 goto bad; 479 } 480 481 /* Shouldn't happen... */ 482 if (m == NULL) { 483 ESPSTAT_INC(esps_crypto); 484 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 485 error = EINVAL; 486 goto bad; 487 } 488 ESPSTAT_INC(esps_hist[sav->alg_enc]); 489 490 /* If authentication was performed, check now. */ 491 if (esph != NULL) { 492 switch (esph->type) { 493 case CRYPTO_SHA2_256_HMAC: 494 case CRYPTO_SHA2_384_HMAC: 495 case CRYPTO_SHA2_512_HMAC: 496 alen = esph->hashsize/2; 497 break; 498 default: 499 alen = AH_HMAC_HASHLEN; 500 break; 501 } 502 AHSTAT_INC(ahs_hist[sav->alg_auth]); 503 /* Copy the authenticator from the packet */ 504 m_copydata(m, m->m_pkthdr.len - alen, alen, aalg); 505 ptr = (caddr_t) (tc + 1); 506 507 /* Verify authenticator */ 508 if (bcmp(ptr, aalg, alen) != 0) { 509 DPRINTF(("%s: authentication hash mismatch for " 510 "packet in SA %s/%08lx\n", __func__, 511 ipsec_address(&saidx->dst, buf, sizeof(buf)), 512 (u_long) ntohl(sav->spi))); 513 ESPSTAT_INC(esps_badauth); 514 error = EACCES; 515 goto bad; 516 } 517 518 /* Remove trailing authenticator */ 519 m_adj(m, -alen); 520 } 521 522 /* Release the crypto descriptors */ 523 free(tc, M_XDATA), tc = NULL; 524 crypto_freereq(crp), crp = NULL; 525 526 /* 527 * Packet is now decrypted. 528 */ 529 m->m_flags |= M_DECRYPTED; 530 531 /* 532 * Update replay sequence number, if appropriate. 533 */ 534 if (sav->replay) { 535 u_int32_t seq; 536 537 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 538 sizeof (seq), (caddr_t) &seq); 539 if (ipsec_updatereplay(ntohl(seq), sav)) { 540 DPRINTF(("%s: packet replay check for %s\n", __func__, 541 ipsec_logsastr(sav, buf, sizeof(buf)))); 542 ESPSTAT_INC(esps_replay); 543 error = ENOBUFS; 544 goto bad; 545 } 546 } 547 548 /* Determine the ESP header length */ 549 if (sav->flags & SADB_X_EXT_OLD) 550 hlen = sizeof (struct esp) + sav->ivlen; 551 else 552 hlen = sizeof (struct newesp) + sav->ivlen; 553 554 /* Remove the ESP header and IV from the mbuf. */ 555 error = m_striphdr(m, skip, hlen); 556 if (error) { 557 ESPSTAT_INC(esps_hdrops); 558 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 559 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 560 (u_long) ntohl(sav->spi))); 561 goto bad; 562 } 563 564 /* Save the last three bytes of decrypted data */ 565 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 566 567 /* Verify pad length */ 568 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 569 ESPSTAT_INC(esps_badilen); 570 DPRINTF(("%s: invalid padding length %d for %u byte packet " 571 "in SA %s/%08lx\n", __func__, lastthree[1], 572 m->m_pkthdr.len - skip, 573 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 574 (u_long) ntohl(sav->spi))); 575 error = EINVAL; 576 goto bad; 577 } 578 579 /* Verify correct decryption by checking the last padding bytes */ 580 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 581 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 582 ESPSTAT_INC(esps_badenc); 583 DPRINTF(("%s: decryption failed for packet in " 584 "SA %s/%08lx\n", __func__, ipsec_address( 585 &sav->sah->saidx.dst, buf, sizeof(buf)), 586 (u_long) ntohl(sav->spi))); 587 error = EINVAL; 588 goto bad; 589 } 590 } 591 592 /* Trim the mbuf chain to remove trailing authenticator and padding */ 593 m_adj(m, -(lastthree[1] + 2)); 594 595 /* Restore the Next Protocol field */ 596 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 597 598 switch (saidx->dst.sa.sa_family) { 599 #ifdef INET6 600 case AF_INET6: 601 error = ipsec6_common_input_cb(m, sav, skip, protoff); 602 break; 603 #endif 604 #ifdef INET 605 case AF_INET: 606 error = ipsec4_common_input_cb(m, sav, skip, protoff); 607 break; 608 #endif 609 default: 610 panic("%s: Unexpected address family: %d saidx=%p", __func__, 611 saidx->dst.sa.sa_family, saidx); 612 } 613 614 KEY_FREESAV(&sav); 615 return error; 616 bad: 617 if (sav) 618 KEY_FREESAV(&sav); 619 if (m != NULL) 620 m_freem(m); 621 if (tc != NULL) 622 free(tc, M_XDATA); 623 if (crp != NULL) 624 crypto_freereq(crp); 625 return error; 626 } 627 628 /* 629 * ESP output routine, called by ipsec[46]_process_packet(). 630 */ 631 static int 632 esp_output(struct mbuf *m, struct ipsecrequest *isr, struct mbuf **mp, 633 int skip, int protoff) 634 { 635 char buf[INET6_ADDRSTRLEN]; 636 struct enc_xform *espx; 637 struct auth_hash *esph; 638 int hlen, rlen, padding, blks, alen, i, roff; 639 struct mbuf *mo = (struct mbuf *) NULL; 640 struct tdb_crypto *tc; 641 struct secasvar *sav; 642 struct secasindex *saidx; 643 unsigned char *pad; 644 u_int8_t prot; 645 int error, maxpacketsize; 646 647 struct cryptodesc *crde = NULL, *crda = NULL; 648 struct cryptop *crp; 649 650 sav = isr->sav; 651 IPSEC_ASSERT(sav != NULL, ("null SA")); 652 esph = sav->tdb_authalgxform; 653 espx = sav->tdb_encalgxform; 654 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 655 656 if (sav->flags & SADB_X_EXT_OLD) 657 hlen = sizeof (struct esp) + sav->ivlen; 658 else 659 hlen = sizeof (struct newesp) + sav->ivlen; 660 661 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 662 /* 663 * NB: The null encoding transform has a blocksize of 4 664 * so that headers are properly aligned. 665 */ 666 blks = espx->blocksize; /* IV blocksize */ 667 668 /* XXX clamp padding length a la KAME??? */ 669 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 670 671 if (esph) 672 switch (esph->type) { 673 case CRYPTO_SHA2_256_HMAC: 674 case CRYPTO_SHA2_384_HMAC: 675 case CRYPTO_SHA2_512_HMAC: 676 alen = esph->hashsize/2; 677 break; 678 default: 679 alen = AH_HMAC_HASHLEN; 680 break; 681 } 682 else 683 alen = 0; 684 685 ESPSTAT_INC(esps_output); 686 687 saidx = &sav->sah->saidx; 688 /* Check for maximum packet size violations. */ 689 switch (saidx->dst.sa.sa_family) { 690 #ifdef INET 691 case AF_INET: 692 maxpacketsize = IP_MAXPACKET; 693 break; 694 #endif /* INET */ 695 #ifdef INET6 696 case AF_INET6: 697 maxpacketsize = IPV6_MAXPACKET; 698 break; 699 #endif /* INET6 */ 700 default: 701 DPRINTF(("%s: unknown/unsupported protocol " 702 "family %d, SA %s/%08lx\n", __func__, 703 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst, 704 buf, sizeof(buf)), (u_long) ntohl(sav->spi))); 705 ESPSTAT_INC(esps_nopf); 706 error = EPFNOSUPPORT; 707 goto bad; 708 } 709 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 710 DPRINTF(("%s: packet in SA %s/%08lx got too big " 711 "(len %u, max len %u)\n", __func__, 712 ipsec_address(&saidx->dst, buf, sizeof(buf)), 713 (u_long) ntohl(sav->spi), 714 skip + hlen + rlen + padding + alen, maxpacketsize)); 715 ESPSTAT_INC(esps_toobig); 716 error = EMSGSIZE; 717 goto bad; 718 } 719 720 /* Update the counters. */ 721 ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip); 722 723 m = m_unshare(m, M_NOWAIT); 724 if (m == NULL) { 725 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 726 ipsec_address(&saidx->dst, buf, sizeof(buf)), 727 (u_long) ntohl(sav->spi))); 728 ESPSTAT_INC(esps_hdrops); 729 error = ENOBUFS; 730 goto bad; 731 } 732 733 /* Inject ESP header. */ 734 mo = m_makespace(m, skip, hlen, &roff); 735 if (mo == NULL) { 736 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 737 __func__, hlen, ipsec_address(&saidx->dst, buf, 738 sizeof(buf)), (u_long) ntohl(sav->spi))); 739 ESPSTAT_INC(esps_hdrops); /* XXX diffs from openbsd */ 740 error = ENOBUFS; 741 goto bad; 742 } 743 744 /* Initialize ESP header. */ 745 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t)); 746 if (sav->replay) { 747 u_int32_t replay; 748 749 #ifdef REGRESSION 750 /* Emulate replay attack when ipsec_replay is TRUE. */ 751 if (!V_ipsec_replay) 752 #endif 753 sav->replay->count++; 754 replay = htonl(sav->replay->count); 755 bcopy((caddr_t) &replay, 756 mtod(mo, caddr_t) + roff + sizeof(u_int32_t), 757 sizeof(u_int32_t)); 758 } 759 760 /* 761 * Add padding -- better to do it ourselves than use the crypto engine, 762 * although if/when we support compression, we'd have to do that. 763 */ 764 pad = (u_char *) m_pad(m, padding + alen); 765 if (pad == NULL) { 766 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 767 ipsec_address(&saidx->dst, buf, sizeof(buf)), 768 (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 char buf[INET6_ADDRSTRLEN]; 880 struct tdb_crypto *tc; 881 struct ipsecrequest *isr; 882 struct secasvar *sav; 883 struct mbuf *m; 884 int error; 885 886 tc = (struct tdb_crypto *) crp->crp_opaque; 887 IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); 888 m = (struct mbuf *) crp->crp_buf; 889 890 isr = tc->tc_isr; 891 IPSEC_ASSERT(isr->sp != NULL, ("NULL isr->sp")); 892 IPSECREQUEST_LOCK(isr); 893 sav = tc->tc_sav; 894 /* With the isr lock released SA pointer can be updated. */ 895 if (sav != isr->sav) { 896 ESPSTAT_INC(esps_notdb); 897 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 898 __func__, ipsec_address(&tc->tc_dst, buf, sizeof(buf)), 899 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 900 error = ENOBUFS; /*XXX*/ 901 goto bad; 902 } 903 904 /* Check for crypto errors. */ 905 if (crp->crp_etype) { 906 /* Reset session ID. */ 907 if (sav->tdb_cryptoid != 0) 908 sav->tdb_cryptoid = crp->crp_sid; 909 910 if (crp->crp_etype == EAGAIN) { 911 IPSECREQUEST_UNLOCK(isr); 912 return (crypto_dispatch(crp)); 913 } 914 915 ESPSTAT_INC(esps_noxform); 916 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 917 error = crp->crp_etype; 918 goto bad; 919 } 920 921 /* Shouldn't happen... */ 922 if (m == NULL) { 923 ESPSTAT_INC(esps_crypto); 924 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 925 error = EINVAL; 926 goto bad; 927 } 928 ESPSTAT_INC(esps_hist[sav->alg_enc]); 929 if (sav->tdb_authalgxform != NULL) 930 AHSTAT_INC(ahs_hist[sav->alg_auth]); 931 932 /* Release crypto descriptors. */ 933 free(tc, M_XDATA); 934 crypto_freereq(crp); 935 936 #ifdef REGRESSION 937 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 938 if (V_ipsec_integrity) { 939 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN]; 940 struct auth_hash *esph; 941 942 /* 943 * Corrupt HMAC if we want to test integrity verification of 944 * the other side. 945 */ 946 esph = sav->tdb_authalgxform; 947 if (esph != NULL) { 948 int alen; 949 950 switch (esph->type) { 951 case CRYPTO_SHA2_256_HMAC: 952 case CRYPTO_SHA2_384_HMAC: 953 case CRYPTO_SHA2_512_HMAC: 954 alen = esph->hashsize/2; 955 break; 956 default: 957 alen = AH_HMAC_HASHLEN; 958 break; 959 } 960 m_copyback(m, m->m_pkthdr.len - alen, 961 alen, ipseczeroes); 962 } 963 } 964 #endif 965 966 /* NB: m is reclaimed by ipsec_process_done. */ 967 error = ipsec_process_done(m, isr); 968 KEY_FREESAV(&sav); 969 IPSECREQUEST_UNLOCK(isr); 970 KEY_FREESP(&isr->sp); 971 return (error); 972 bad: 973 if (sav) 974 KEY_FREESAV(&sav); 975 IPSECREQUEST_UNLOCK(isr); 976 KEY_FREESP(&isr->sp); 977 if (m) 978 m_freem(m); 979 free(tc, M_XDATA); 980 crypto_freereq(crp); 981 return (error); 982 } 983 984 static struct xformsw esp_xformsw = { 985 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 986 esp_init, esp_zeroize, esp_input, 987 esp_output 988 }; 989 990 static void 991 esp_attach(void) 992 { 993 994 xform_register(&esp_xformsw); 995 } 996 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL); 997