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 /* max iv length over all algorithms */ 89 static VNET_DEFINE(int, esp_max_ivlen) = 0; 90 #define V_esp_max_ivlen VNET(esp_max_ivlen) 91 92 static int esp_input_cb(struct cryptop *op); 93 static int esp_output_cb(struct cryptop *crp); 94 95 /* 96 * NB: this is public for use by the PF_KEY support. 97 * NB: if you add support here; be sure to add code to esp_attach below! 98 */ 99 struct enc_xform * 100 esp_algorithm_lookup(int alg) 101 { 102 if (alg >= ESP_ALG_MAX) 103 return NULL; 104 switch (alg) { 105 case SADB_EALG_DESCBC: 106 return &enc_xform_des; 107 case SADB_EALG_3DESCBC: 108 return &enc_xform_3des; 109 case SADB_X_EALG_AES: 110 return &enc_xform_rijndael128; 111 case SADB_X_EALG_BLOWFISHCBC: 112 return &enc_xform_blf; 113 case SADB_X_EALG_CAST128CBC: 114 return &enc_xform_cast5; 115 case SADB_X_EALG_SKIPJACK: 116 return &enc_xform_skipjack; 117 case SADB_EALG_NULL: 118 return &enc_xform_null; 119 case SADB_X_EALG_CAMELLIACBC: 120 return &enc_xform_camellia; 121 } 122 return NULL; 123 } 124 125 size_t 126 esp_hdrsiz(struct secasvar *sav) 127 { 128 size_t size; 129 130 if (sav != NULL) { 131 /*XXX not right for null algorithm--does it matter??*/ 132 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 133 ("SA with null xform")); 134 if (sav->flags & SADB_X_EXT_OLD) 135 size = sizeof (struct esp); 136 else 137 size = sizeof (struct newesp); 138 size += sav->tdb_encalgxform->blocksize + 9; 139 /*XXX need alg check???*/ 140 if (sav->tdb_authalgxform != NULL && sav->replay) 141 size += ah_hdrsiz(sav); 142 } else { 143 /* 144 * base header size 145 * + max iv length for CBC mode 146 * + max pad length 147 * + sizeof (pad length field) 148 * + sizeof (next header field) 149 * + max icv supported. 150 */ 151 size = sizeof (struct newesp) + V_esp_max_ivlen + 9 + 16; 152 } 153 return size; 154 } 155 156 /* 157 * esp_init() is called when an SPI is being set up. 158 */ 159 static int 160 esp_init(struct secasvar *sav, struct xformsw *xsp) 161 { 162 struct enc_xform *txform; 163 struct cryptoini cria, crie; 164 int keylen; 165 int error; 166 167 txform = esp_algorithm_lookup(sav->alg_enc); 168 if (txform == NULL) { 169 DPRINTF(("%s: unsupported encryption algorithm %d\n", 170 __func__, sav->alg_enc)); 171 return EINVAL; 172 } 173 if (sav->key_enc == NULL) { 174 DPRINTF(("%s: no encoding key for %s algorithm\n", 175 __func__, txform->name)); 176 return EINVAL; 177 } 178 if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) { 179 DPRINTF(("%s: 4-byte IV not supported with protocol\n", 180 __func__)); 181 return EINVAL; 182 } 183 keylen = _KEYLEN(sav->key_enc); 184 if (txform->minkey > keylen || keylen > txform->maxkey) { 185 DPRINTF(("%s: invalid key length %u, must be in the range " 186 "[%u..%u] for algorithm %s\n", __func__, 187 keylen, txform->minkey, txform->maxkey, 188 txform->name)); 189 return EINVAL; 190 } 191 192 /* 193 * NB: The null xform needs a non-zero blocksize to keep the 194 * crypto code happy but if we use it to set ivlen then 195 * the ESP header will be processed incorrectly. The 196 * compromise is to force it to zero here. 197 */ 198 sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize); 199 sav->iv = (caddr_t) malloc(sav->ivlen, M_XDATA, M_WAITOK); 200 if (sav->iv == NULL) { 201 DPRINTF(("%s: no memory for IV\n", __func__)); 202 return EINVAL; 203 } 204 key_randomfill(sav->iv, sav->ivlen); /*XXX*/ 205 206 /* 207 * Setup AH-related state. 208 */ 209 if (sav->alg_auth != 0) { 210 error = ah_init0(sav, xsp, &cria); 211 if (error) 212 return error; 213 } 214 215 /* NB: override anything set in ah_init0 */ 216 sav->tdb_xform = xsp; 217 sav->tdb_encalgxform = txform; 218 219 /* Initialize crypto session. */ 220 bzero(&crie, sizeof (crie)); 221 crie.cri_alg = sav->tdb_encalgxform->type; 222 crie.cri_klen = _KEYBITS(sav->key_enc); 223 crie.cri_key = sav->key_enc->key_data; 224 /* XXX Rounds ? */ 225 226 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 227 /* init both auth & enc */ 228 crie.cri_next = &cria; 229 error = crypto_newsession(&sav->tdb_cryptoid, 230 &crie, V_crypto_support); 231 } else if (sav->tdb_encalgxform) { 232 error = crypto_newsession(&sav->tdb_cryptoid, 233 &crie, V_crypto_support); 234 } else if (sav->tdb_authalgxform) { 235 error = crypto_newsession(&sav->tdb_cryptoid, 236 &cria, V_crypto_support); 237 } else { 238 /* XXX cannot happen? */ 239 DPRINTF(("%s: no encoding OR authentication xform!\n", 240 __func__)); 241 error = EINVAL; 242 } 243 return error; 244 } 245 246 /* 247 * Paranoia. 248 */ 249 static int 250 esp_zeroize(struct secasvar *sav) 251 { 252 /* NB: ah_zerorize free's the crypto session state */ 253 int error = ah_zeroize(sav); 254 255 if (sav->key_enc) 256 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc)); 257 if (sav->iv) { 258 free(sav->iv, M_XDATA); 259 sav->iv = NULL; 260 } 261 sav->tdb_encalgxform = NULL; 262 sav->tdb_xform = NULL; 263 return error; 264 } 265 266 /* 267 * ESP input processing, called (eventually) through the protocol switch. 268 */ 269 static int 270 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 271 { 272 struct auth_hash *esph; 273 struct enc_xform *espx; 274 struct tdb_ident *tdbi; 275 struct tdb_crypto *tc; 276 int plen, alen, hlen; 277 struct m_tag *mtag; 278 struct newesp *esp; 279 280 struct cryptodesc *crde; 281 struct cryptop *crp; 282 283 IPSEC_ASSERT(sav != NULL, ("null SA")); 284 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); 285 286 /* Valid IP Packet length ? */ 287 if ( (skip&3) || (m->m_pkthdr.len&3) ){ 288 DPRINTF(("%s: misaligned packet, skip %u pkt len %u", 289 __func__, skip, m->m_pkthdr.len)); 290 V_espstat.esps_badilen++; 291 m_freem(m); 292 return EINVAL; 293 } 294 295 /* XXX don't pullup, just copy header */ 296 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 297 298 esph = sav->tdb_authalgxform; 299 espx = sav->tdb_encalgxform; 300 301 /* Determine the ESP header length */ 302 if (sav->flags & SADB_X_EXT_OLD) 303 hlen = sizeof (struct esp) + sav->ivlen; 304 else 305 hlen = sizeof (struct newesp) + sav->ivlen; 306 /* Authenticator hash size */ 307 alen = esph ? AH_HMAC_HASHLEN : 0; 308 309 /* 310 * Verify payload length is multiple of encryption algorithm 311 * block size. 312 * 313 * NB: This works for the null algorithm because the blocksize 314 * is 4 and all packets must be 4-byte aligned regardless 315 * of the algorithm. 316 */ 317 plen = m->m_pkthdr.len - (skip + hlen + alen); 318 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 319 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 320 " SA %s/%08lx\n", __func__, 321 plen, espx->blocksize, 322 ipsec_address(&sav->sah->saidx.dst), 323 (u_long) ntohl(sav->spi))); 324 V_espstat.esps_badilen++; 325 m_freem(m); 326 return EINVAL; 327 } 328 329 /* 330 * Check sequence number. 331 */ 332 if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) { 333 DPRINTF(("%s: packet replay check for %s\n", __func__, 334 ipsec_logsastr(sav))); /*XXX*/ 335 V_espstat.esps_replay++; 336 m_freem(m); 337 return ENOBUFS; /*XXX*/ 338 } 339 340 /* Update the counters */ 341 V_espstat.esps_ibytes += m->m_pkthdr.len - (skip + hlen + alen); 342 343 /* Find out if we've already done crypto */ 344 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL); 345 mtag != NULL; 346 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) { 347 tdbi = (struct tdb_ident *) (mtag + 1); 348 if (tdbi->proto == sav->sah->saidx.proto && 349 tdbi->spi == sav->spi && 350 !bcmp(&tdbi->dst, &sav->sah->saidx.dst, 351 sizeof(union sockaddr_union))) 352 break; 353 } 354 355 /* Get crypto descriptors */ 356 crp = crypto_getreq(esph && espx ? 2 : 1); 357 if (crp == NULL) { 358 DPRINTF(("%s: failed to acquire crypto descriptors\n", 359 __func__)); 360 V_espstat.esps_crypto++; 361 m_freem(m); 362 return ENOBUFS; 363 } 364 365 /* Get IPsec-specific opaque pointer */ 366 if (esph == NULL || mtag != NULL) 367 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 368 M_XDATA, M_NOWAIT|M_ZERO); 369 else 370 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen, 371 M_XDATA, M_NOWAIT|M_ZERO); 372 if (tc == NULL) { 373 crypto_freereq(crp); 374 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 375 V_espstat.esps_crypto++; 376 m_freem(m); 377 return ENOBUFS; 378 } 379 380 tc->tc_ptr = (caddr_t) mtag; 381 382 if (esph) { 383 struct cryptodesc *crda = crp->crp_desc; 384 385 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor")); 386 387 /* Authentication descriptor */ 388 crda->crd_skip = skip; 389 crda->crd_len = m->m_pkthdr.len - (skip + alen); 390 crda->crd_inject = m->m_pkthdr.len - alen; 391 392 crda->crd_alg = esph->type; 393 crda->crd_key = sav->key_auth->key_data; 394 crda->crd_klen = _KEYBITS(sav->key_auth); 395 396 /* Copy the authenticator */ 397 if (mtag == NULL) 398 m_copydata(m, m->m_pkthdr.len - alen, alen, 399 (caddr_t) (tc + 1)); 400 401 /* Chain authentication request */ 402 crde = crda->crd_next; 403 } else { 404 crde = crp->crp_desc; 405 } 406 407 /* Crypto operation descriptor */ 408 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 409 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 410 crp->crp_buf = (caddr_t) m; 411 crp->crp_callback = esp_input_cb; 412 crp->crp_sid = sav->tdb_cryptoid; 413 crp->crp_opaque = (caddr_t) tc; 414 415 /* These are passed as-is to the callback */ 416 tc->tc_spi = sav->spi; 417 tc->tc_dst = sav->sah->saidx.dst; 418 tc->tc_proto = sav->sah->saidx.proto; 419 tc->tc_protoff = protoff; 420 tc->tc_skip = skip; 421 422 /* Decryption descriptor */ 423 if (espx) { 424 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor")); 425 crde->crd_skip = skip + hlen; 426 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 427 crde->crd_inject = skip + hlen - sav->ivlen; 428 429 crde->crd_alg = espx->type; 430 crde->crd_key = sav->key_enc->key_data; 431 crde->crd_klen = _KEYBITS(sav->key_enc); 432 /* XXX Rounds ? */ 433 } 434 435 if (mtag == NULL) 436 return crypto_dispatch(crp); 437 else 438 return esp_input_cb(crp); 439 } 440 441 #ifdef INET6 442 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \ 443 if (saidx->dst.sa.sa_family == AF_INET6) { \ 444 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \ 445 } else { \ 446 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \ 447 } \ 448 } while (0) 449 #else 450 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \ 451 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag)) 452 #endif 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_HASHLEN]; 461 int hlen, skip, protoff, error; 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 = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 483 if (sav == NULL) { 484 V_espstat.esps_notdb++; 485 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 486 __func__, ipsec_address(&tc->tc_dst), 487 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 488 error = ENOBUFS; /*XXX*/ 489 goto bad; 490 } 491 492 saidx = &sav->sah->saidx; 493 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 494 saidx->dst.sa.sa_family == AF_INET6, 495 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 496 497 esph = sav->tdb_authalgxform; 498 espx = sav->tdb_encalgxform; 499 500 /* Check for crypto errors */ 501 if (crp->crp_etype) { 502 /* Reset the session ID */ 503 if (sav->tdb_cryptoid != 0) 504 sav->tdb_cryptoid = crp->crp_sid; 505 506 if (crp->crp_etype == EAGAIN) { 507 KEY_FREESAV(&sav); 508 error = crypto_dispatch(crp); 509 return error; 510 } 511 512 V_espstat.esps_noxform++; 513 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 514 error = crp->crp_etype; 515 goto bad; 516 } 517 518 /* Shouldn't happen... */ 519 if (m == NULL) { 520 V_espstat.esps_crypto++; 521 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 522 error = EINVAL; 523 goto bad; 524 } 525 V_espstat.esps_hist[sav->alg_enc]++; 526 527 /* If authentication was performed, check now. */ 528 if (esph != NULL) { 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 V_ahstat.ahs_hist[sav->alg_auth]++; 535 if (mtag == NULL) { 536 /* Copy the authenticator from the packet */ 537 m_copydata(m, m->m_pkthdr.len - AH_HMAC_HASHLEN, 538 AH_HMAC_HASHLEN, aalg); 539 540 ptr = (caddr_t) (tc + 1); 541 542 /* Verify authenticator */ 543 if (bcmp(ptr, aalg, AH_HMAC_HASHLEN) != 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 V_espstat.esps_badauth++; 550 error = EACCES; 551 goto bad; 552 } 553 } 554 555 /* Remove trailing authenticator */ 556 m_adj(m, -AH_HMAC_HASHLEN); 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 V_espstat.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 V_espstat.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 V_espstat.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 V_espstat.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 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag); 636 637 KEY_FREESAV(&sav); 638 return error; 639 bad: 640 if (sav) 641 KEY_FREESAV(&sav); 642 if (m != NULL) 643 m_freem(m); 644 if (tc != NULL) 645 free(tc, M_XDATA); 646 if (crp != NULL) 647 crypto_freereq(crp); 648 return error; 649 } 650 651 /* 652 * ESP output routine, called by ipsec[46]_process_packet(). 653 */ 654 static int 655 esp_output( 656 struct mbuf *m, 657 struct ipsecrequest *isr, 658 struct mbuf **mp, 659 int skip, 660 int protoff 661 ) 662 { 663 struct enc_xform *espx; 664 struct auth_hash *esph; 665 int hlen, rlen, plen, padding, blks, alen, i, roff; 666 struct mbuf *mo = (struct mbuf *) NULL; 667 struct tdb_crypto *tc; 668 struct secasvar *sav; 669 struct secasindex *saidx; 670 unsigned char *pad; 671 u_int8_t prot; 672 int error, maxpacketsize; 673 674 struct cryptodesc *crde = NULL, *crda = NULL; 675 struct cryptop *crp; 676 677 sav = isr->sav; 678 IPSEC_ASSERT(sav != NULL, ("null SA")); 679 esph = sav->tdb_authalgxform; 680 espx = sav->tdb_encalgxform; 681 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 682 683 if (sav->flags & SADB_X_EXT_OLD) 684 hlen = sizeof (struct esp) + sav->ivlen; 685 else 686 hlen = sizeof (struct newesp) + sav->ivlen; 687 688 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 689 /* 690 * NB: The null encoding transform has a blocksize of 4 691 * so that headers are properly aligned. 692 */ 693 blks = espx->blocksize; /* IV blocksize */ 694 695 /* XXX clamp padding length a la KAME??? */ 696 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 697 plen = rlen + padding; /* Padded payload length. */ 698 699 if (esph) 700 alen = AH_HMAC_HASHLEN; 701 else 702 alen = 0; 703 704 V_espstat.esps_output++; 705 706 saidx = &sav->sah->saidx; 707 /* Check for maximum packet size violations. */ 708 switch (saidx->dst.sa.sa_family) { 709 #ifdef INET 710 case AF_INET: 711 maxpacketsize = IP_MAXPACKET; 712 break; 713 #endif /* INET */ 714 #ifdef INET6 715 case AF_INET6: 716 maxpacketsize = IPV6_MAXPACKET; 717 break; 718 #endif /* INET6 */ 719 default: 720 DPRINTF(("%s: unknown/unsupported protocol " 721 "family %d, SA %s/%08lx\n", __func__, 722 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst), 723 (u_long) ntohl(sav->spi))); 724 V_espstat.esps_nopf++; 725 error = EPFNOSUPPORT; 726 goto bad; 727 } 728 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 729 DPRINTF(("%s: packet in SA %s/%08lx got too big " 730 "(len %u, max len %u)\n", __func__, 731 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi), 732 skip + hlen + rlen + padding + alen, maxpacketsize)); 733 V_espstat.esps_toobig++; 734 error = EMSGSIZE; 735 goto bad; 736 } 737 738 /* Update the counters. */ 739 V_espstat.esps_obytes += m->m_pkthdr.len - skip; 740 741 m = m_unshare(m, M_NOWAIT); 742 if (m == NULL) { 743 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 744 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 745 V_espstat.esps_hdrops++; 746 error = ENOBUFS; 747 goto bad; 748 } 749 750 /* Inject ESP header. */ 751 mo = m_makespace(m, skip, hlen, &roff); 752 if (mo == NULL) { 753 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 754 __func__, hlen, ipsec_address(&saidx->dst), 755 (u_long) ntohl(sav->spi))); 756 V_espstat.esps_hdrops++; /* XXX diffs from openbsd */ 757 error = ENOBUFS; 758 goto bad; 759 } 760 761 /* Initialize ESP header. */ 762 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t)); 763 if (sav->replay) { 764 u_int32_t replay; 765 766 #ifdef REGRESSION 767 /* Emulate replay attack when ipsec_replay is TRUE. */ 768 if (!V_ipsec_replay) 769 #endif 770 sav->replay->count++; 771 replay = htonl(sav->replay->count); 772 bcopy((caddr_t) &replay, 773 mtod(mo, caddr_t) + roff + sizeof(u_int32_t), 774 sizeof(u_int32_t)); 775 } 776 777 /* 778 * Add padding -- better to do it ourselves than use the crypto engine, 779 * although if/when we support compression, we'd have to do that. 780 */ 781 pad = (u_char *) m_pad(m, padding + alen); 782 if (pad == NULL) { 783 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 784 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 785 m = NULL; /* NB: free'd by m_pad */ 786 error = ENOBUFS; 787 goto bad; 788 } 789 790 /* 791 * Add padding: random, zero, or self-describing. 792 * XXX catch unexpected setting 793 */ 794 switch (sav->flags & SADB_X_EXT_PMASK) { 795 case SADB_X_EXT_PRAND: 796 (void) read_random(pad, padding - 2); 797 break; 798 case SADB_X_EXT_PZERO: 799 bzero(pad, padding - 2); 800 break; 801 case SADB_X_EXT_PSEQ: 802 for (i = 0; i < padding - 2; i++) 803 pad[i] = i+1; 804 break; 805 } 806 807 /* Fix padding length and Next Protocol in padding itself. */ 808 pad[padding - 2] = padding - 2; 809 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 810 811 /* Fix Next Protocol in IPv4/IPv6 header. */ 812 prot = IPPROTO_ESP; 813 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 814 815 /* Get crypto descriptors. */ 816 crp = crypto_getreq(esph && espx ? 2 : 1); 817 if (crp == NULL) { 818 DPRINTF(("%s: failed to acquire crypto descriptors\n", 819 __func__)); 820 V_espstat.esps_crypto++; 821 error = ENOBUFS; 822 goto bad; 823 } 824 825 if (espx) { 826 crde = crp->crp_desc; 827 crda = crde->crd_next; 828 829 /* Encryption descriptor. */ 830 crde->crd_skip = skip + hlen; 831 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 832 crde->crd_flags = CRD_F_ENCRYPT; 833 crde->crd_inject = skip + hlen - sav->ivlen; 834 835 /* Encryption operation. */ 836 crde->crd_alg = espx->type; 837 crde->crd_key = sav->key_enc->key_data; 838 crde->crd_klen = _KEYBITS(sav->key_enc); 839 /* XXX Rounds ? */ 840 } else 841 crda = crp->crp_desc; 842 843 /* IPsec-specific opaque crypto info. */ 844 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 845 M_XDATA, M_NOWAIT|M_ZERO); 846 if (tc == NULL) { 847 crypto_freereq(crp); 848 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 849 V_espstat.esps_crypto++; 850 error = ENOBUFS; 851 goto bad; 852 } 853 854 /* Callback parameters */ 855 tc->tc_isr = isr; 856 tc->tc_spi = sav->spi; 857 tc->tc_dst = saidx->dst; 858 tc->tc_proto = saidx->proto; 859 860 /* Crypto operation descriptor. */ 861 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 862 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 863 crp->crp_buf = (caddr_t) m; 864 crp->crp_callback = esp_output_cb; 865 crp->crp_opaque = (caddr_t) tc; 866 crp->crp_sid = sav->tdb_cryptoid; 867 868 if (esph) { 869 /* Authentication descriptor. */ 870 crda->crd_skip = skip; 871 crda->crd_len = m->m_pkthdr.len - (skip + alen); 872 crda->crd_inject = m->m_pkthdr.len - alen; 873 874 /* Authentication operation. */ 875 crda->crd_alg = esph->type; 876 crda->crd_key = sav->key_auth->key_data; 877 crda->crd_klen = _KEYBITS(sav->key_auth); 878 } 879 880 return crypto_dispatch(crp); 881 bad: 882 if (m) 883 m_freem(m); 884 return (error); 885 } 886 887 /* 888 * ESP output callback from the crypto driver. 889 */ 890 static int 891 esp_output_cb(struct cryptop *crp) 892 { 893 struct tdb_crypto *tc; 894 struct ipsecrequest *isr; 895 struct secasvar *sav; 896 struct mbuf *m; 897 int err, error; 898 899 tc = (struct tdb_crypto *) crp->crp_opaque; 900 IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); 901 m = (struct mbuf *) crp->crp_buf; 902 903 isr = tc->tc_isr; 904 IPSECREQUEST_LOCK(isr); 905 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 906 if (sav == NULL) { 907 V_espstat.esps_notdb++; 908 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 909 __func__, ipsec_address(&tc->tc_dst), 910 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 911 error = ENOBUFS; /*XXX*/ 912 goto bad; 913 } 914 IPSEC_ASSERT(isr->sav == sav, 915 ("SA changed was %p now %p\n", isr->sav, sav)); 916 917 /* Check for crypto errors. */ 918 if (crp->crp_etype) { 919 /* Reset session ID. */ 920 if (sav->tdb_cryptoid != 0) 921 sav->tdb_cryptoid = crp->crp_sid; 922 923 if (crp->crp_etype == EAGAIN) { 924 KEY_FREESAV(&sav); 925 IPSECREQUEST_UNLOCK(isr); 926 error = crypto_dispatch(crp); 927 return error; 928 } 929 930 V_espstat.esps_noxform++; 931 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 932 error = crp->crp_etype; 933 goto bad; 934 } 935 936 /* Shouldn't happen... */ 937 if (m == NULL) { 938 V_espstat.esps_crypto++; 939 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 940 error = EINVAL; 941 goto bad; 942 } 943 V_espstat.esps_hist[sav->alg_enc]++; 944 if (sav->tdb_authalgxform != NULL) 945 V_ahstat.ahs_hist[sav->alg_auth]++; 946 947 /* Release crypto descriptors. */ 948 free(tc, M_XDATA); 949 crypto_freereq(crp); 950 951 #ifdef REGRESSION 952 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 953 if (V_ipsec_integrity) { 954 static unsigned char ipseczeroes[AH_HMAC_HASHLEN]; 955 struct auth_hash *esph; 956 957 /* 958 * Corrupt HMAC if we want to test integrity verification of 959 * the other side. 960 */ 961 esph = sav->tdb_authalgxform; 962 if (esph != NULL) { 963 m_copyback(m, m->m_pkthdr.len - AH_HMAC_HASHLEN, 964 AH_HMAC_HASHLEN, ipseczeroes); 965 } 966 } 967 #endif 968 969 /* NB: m is reclaimed by ipsec_process_done. */ 970 err = ipsec_process_done(m, isr); 971 KEY_FREESAV(&sav); 972 IPSECREQUEST_UNLOCK(isr); 973 return err; 974 bad: 975 if (sav) 976 KEY_FREESAV(&sav); 977 IPSECREQUEST_UNLOCK(isr); 978 if (m) 979 m_freem(m); 980 free(tc, M_XDATA); 981 crypto_freereq(crp); 982 return error; 983 } 984 985 static struct xformsw esp_xformsw = { 986 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 987 esp_init, esp_zeroize, esp_input, 988 esp_output 989 }; 990 991 static void 992 esp_attach(void) 993 { 994 #define MAXIV(xform) \ 995 if (xform.blocksize > V_esp_max_ivlen) \ 996 V_esp_max_ivlen = xform.blocksize \ 997 998 MAXIV(enc_xform_des); /* SADB_EALG_DESCBC */ 999 MAXIV(enc_xform_3des); /* SADB_EALG_3DESCBC */ 1000 MAXIV(enc_xform_rijndael128); /* SADB_X_EALG_AES */ 1001 MAXIV(enc_xform_blf); /* SADB_X_EALG_BLOWFISHCBC */ 1002 MAXIV(enc_xform_cast5); /* SADB_X_EALG_CAST128CBC */ 1003 MAXIV(enc_xform_skipjack); /* SADB_X_EALG_SKIPJACK */ 1004 MAXIV(enc_xform_null); /* SADB_EALG_NULL */ 1005 MAXIV(enc_xform_camellia); /* SADB_X_EALG_CAMELLIACBC */ 1006 1007 xform_register(&esp_xformsw); 1008 #undef MAXIV 1009 } 1010 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL); 1011