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 #include <sys/vimage.h> 50 51 #include <net/if.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 int esp_enable = 1; 80 struct espstat espstat; 81 82 SYSCTL_DECL(_net_inet_esp); 83 SYSCTL_V_INT(V_NET, vnet_ipsec,_net_inet_esp, OID_AUTO, 84 esp_enable, CTLFLAG_RW, esp_enable, 0, ""); 85 SYSCTL_V_STRUCT(V_NET, vnet_ipsec, _net_inet_esp, IPSECCTL_STATS, 86 stats, CTLFLAG_RD, espstat, espstat, ""); 87 88 static int esp_max_ivlen; /* max iv length over all algorithms */ 89 90 static int esp_input_cb(struct cryptop *op); 91 static int esp_output_cb(struct cryptop *crp); 92 93 /* 94 * NB: this is public for use by the PF_KEY support. 95 * NB: if you add support here; be sure to add code to esp_attach below! 96 */ 97 struct enc_xform * 98 esp_algorithm_lookup(int alg) 99 { 100 if (alg >= ESP_ALG_MAX) 101 return NULL; 102 switch (alg) { 103 case SADB_EALG_DESCBC: 104 return &enc_xform_des; 105 case SADB_EALG_3DESCBC: 106 return &enc_xform_3des; 107 case SADB_X_EALG_AES: 108 return &enc_xform_rijndael128; 109 case SADB_X_EALG_BLOWFISHCBC: 110 return &enc_xform_blf; 111 case SADB_X_EALG_CAST128CBC: 112 return &enc_xform_cast5; 113 case SADB_X_EALG_SKIPJACK: 114 return &enc_xform_skipjack; 115 case SADB_EALG_NULL: 116 return &enc_xform_null; 117 case SADB_X_EALG_CAMELLIACBC: 118 return &enc_xform_camellia; 119 } 120 return NULL; 121 } 122 123 size_t 124 esp_hdrsiz(struct secasvar *sav) 125 { 126 INIT_VNET_IPSEC(curvnet); 127 size_t size; 128 129 if (sav != NULL) { 130 /*XXX not right for null algorithm--does it matter??*/ 131 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 132 ("SA with null xform")); 133 if (sav->flags & SADB_X_EXT_OLD) 134 size = sizeof (struct esp); 135 else 136 size = sizeof (struct newesp); 137 size += sav->tdb_encalgxform->blocksize + 9; 138 /*XXX need alg check???*/ 139 if (sav->tdb_authalgxform != NULL && sav->replay) 140 size += ah_hdrsiz(sav); 141 } else { 142 /* 143 * base header size 144 * + max iv length for CBC mode 145 * + max pad length 146 * + sizeof (pad length field) 147 * + sizeof (next header field) 148 * + max icv supported. 149 */ 150 size = sizeof (struct newesp) + V_esp_max_ivlen + 9 + 16; 151 } 152 return size; 153 } 154 155 /* 156 * esp_init() is called when an SPI is being set up. 157 */ 158 static int 159 esp_init(struct secasvar *sav, struct xformsw *xsp) 160 { 161 INIT_VNET_IPSEC(curvnet); 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 INIT_VNET_IPSEC(curvnet); 273 struct auth_hash *esph; 274 struct enc_xform *espx; 275 struct tdb_ident *tdbi; 276 struct tdb_crypto *tc; 277 int plen, alen, hlen; 278 struct m_tag *mtag; 279 struct newesp *esp; 280 281 struct cryptodesc *crde; 282 struct cryptop *crp; 283 284 IPSEC_ASSERT(sav != NULL, ("null SA")); 285 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); 286 IPSEC_ASSERT((skip&3) == 0 && (m->m_pkthdr.len&3) == 0, 287 ("misaligned packet, skip %u pkt len %u", 288 skip, m->m_pkthdr.len)); 289 290 /* XXX don't pullup, just copy header */ 291 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 292 293 esph = sav->tdb_authalgxform; 294 espx = sav->tdb_encalgxform; 295 296 /* Determine the ESP header length */ 297 if (sav->flags & SADB_X_EXT_OLD) 298 hlen = sizeof (struct esp) + sav->ivlen; 299 else 300 hlen = sizeof (struct newesp) + sav->ivlen; 301 /* Authenticator hash size */ 302 alen = esph ? AH_HMAC_HASHLEN : 0; 303 304 /* 305 * Verify payload length is multiple of encryption algorithm 306 * block size. 307 * 308 * NB: This works for the null algorithm because the blocksize 309 * is 4 and all packets must be 4-byte aligned regardless 310 * of the algorithm. 311 */ 312 plen = m->m_pkthdr.len - (skip + hlen + alen); 313 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 314 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 315 " SA %s/%08lx\n", __func__, 316 plen, espx->blocksize, 317 ipsec_address(&sav->sah->saidx.dst), 318 (u_long) ntohl(sav->spi))); 319 V_espstat.esps_badilen++; 320 m_freem(m); 321 return EINVAL; 322 } 323 324 /* 325 * Check sequence number. 326 */ 327 if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) { 328 DPRINTF(("%s: packet replay check for %s\n", __func__, 329 ipsec_logsastr(sav))); /*XXX*/ 330 V_espstat.esps_replay++; 331 m_freem(m); 332 return ENOBUFS; /*XXX*/ 333 } 334 335 /* Update the counters */ 336 V_espstat.esps_ibytes += m->m_pkthdr.len - (skip + hlen + alen); 337 338 /* Find out if we've already done crypto */ 339 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL); 340 mtag != NULL; 341 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) { 342 tdbi = (struct tdb_ident *) (mtag + 1); 343 if (tdbi->proto == sav->sah->saidx.proto && 344 tdbi->spi == sav->spi && 345 !bcmp(&tdbi->dst, &sav->sah->saidx.dst, 346 sizeof(union sockaddr_union))) 347 break; 348 } 349 350 /* Get crypto descriptors */ 351 crp = crypto_getreq(esph && espx ? 2 : 1); 352 if (crp == NULL) { 353 DPRINTF(("%s: failed to acquire crypto descriptors\n", 354 __func__)); 355 V_espstat.esps_crypto++; 356 m_freem(m); 357 return ENOBUFS; 358 } 359 360 /* Get IPsec-specific opaque pointer */ 361 if (esph == NULL || mtag != NULL) 362 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 363 M_XDATA, M_NOWAIT|M_ZERO); 364 else 365 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen, 366 M_XDATA, M_NOWAIT|M_ZERO); 367 if (tc == NULL) { 368 crypto_freereq(crp); 369 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 370 V_espstat.esps_crypto++; 371 m_freem(m); 372 return ENOBUFS; 373 } 374 375 tc->tc_ptr = (caddr_t) mtag; 376 377 if (esph) { 378 struct cryptodesc *crda = crp->crp_desc; 379 380 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor")); 381 382 /* Authentication descriptor */ 383 crda->crd_skip = skip; 384 crda->crd_len = m->m_pkthdr.len - (skip + alen); 385 crda->crd_inject = m->m_pkthdr.len - alen; 386 387 crda->crd_alg = esph->type; 388 crda->crd_key = sav->key_auth->key_data; 389 crda->crd_klen = _KEYBITS(sav->key_auth); 390 391 /* Copy the authenticator */ 392 if (mtag == NULL) 393 m_copydata(m, m->m_pkthdr.len - alen, alen, 394 (caddr_t) (tc + 1)); 395 396 /* Chain authentication request */ 397 crde = crda->crd_next; 398 } else { 399 crde = crp->crp_desc; 400 } 401 402 /* Crypto operation descriptor */ 403 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 404 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 405 crp->crp_buf = (caddr_t) m; 406 crp->crp_callback = esp_input_cb; 407 crp->crp_sid = sav->tdb_cryptoid; 408 crp->crp_opaque = (caddr_t) tc; 409 410 /* These are passed as-is to the callback */ 411 tc->tc_spi = sav->spi; 412 tc->tc_dst = sav->sah->saidx.dst; 413 tc->tc_proto = sav->sah->saidx.proto; 414 tc->tc_protoff = protoff; 415 tc->tc_skip = skip; 416 417 /* Decryption descriptor */ 418 if (espx) { 419 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor")); 420 crde->crd_skip = skip + hlen; 421 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 422 crde->crd_inject = skip + hlen - sav->ivlen; 423 424 crde->crd_alg = espx->type; 425 crde->crd_key = sav->key_enc->key_data; 426 crde->crd_klen = _KEYBITS(sav->key_enc); 427 /* XXX Rounds ? */ 428 } 429 430 if (mtag == NULL) 431 return crypto_dispatch(crp); 432 else 433 return esp_input_cb(crp); 434 } 435 436 #ifdef INET6 437 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \ 438 if (saidx->dst.sa.sa_family == AF_INET6) { \ 439 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \ 440 } else { \ 441 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \ 442 } \ 443 } while (0) 444 #else 445 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \ 446 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag)) 447 #endif 448 449 /* 450 * ESP input callback from the crypto driver. 451 */ 452 static int 453 esp_input_cb(struct cryptop *crp) 454 { 455 INIT_VNET_IPSEC(curvnet); 456 u_int8_t lastthree[3], aalg[AH_HMAC_HASHLEN]; 457 int hlen, skip, protoff, error; 458 struct mbuf *m; 459 struct cryptodesc *crd; 460 struct auth_hash *esph; 461 struct enc_xform *espx; 462 struct tdb_crypto *tc; 463 struct m_tag *mtag; 464 struct secasvar *sav; 465 struct secasindex *saidx; 466 caddr_t ptr; 467 468 crd = crp->crp_desc; 469 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!")); 470 471 tc = (struct tdb_crypto *) crp->crp_opaque; 472 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!")); 473 skip = tc->tc_skip; 474 protoff = tc->tc_protoff; 475 mtag = (struct m_tag *) tc->tc_ptr; 476 m = (struct mbuf *) crp->crp_buf; 477 478 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 479 if (sav == NULL) { 480 V_espstat.esps_notdb++; 481 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 482 __func__, ipsec_address(&tc->tc_dst), 483 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 484 error = ENOBUFS; /*XXX*/ 485 goto bad; 486 } 487 488 saidx = &sav->sah->saidx; 489 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 490 saidx->dst.sa.sa_family == AF_INET6, 491 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 492 493 esph = sav->tdb_authalgxform; 494 espx = sav->tdb_encalgxform; 495 496 /* Check for crypto errors */ 497 if (crp->crp_etype) { 498 /* Reset the session ID */ 499 if (sav->tdb_cryptoid != 0) 500 sav->tdb_cryptoid = crp->crp_sid; 501 502 if (crp->crp_etype == EAGAIN) { 503 KEY_FREESAV(&sav); 504 error = crypto_dispatch(crp); 505 return error; 506 } 507 508 V_espstat.esps_noxform++; 509 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 510 error = crp->crp_etype; 511 goto bad; 512 } 513 514 /* Shouldn't happen... */ 515 if (m == NULL) { 516 V_espstat.esps_crypto++; 517 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 518 error = EINVAL; 519 goto bad; 520 } 521 V_espstat.esps_hist[sav->alg_enc]++; 522 523 /* If authentication was performed, check now. */ 524 if (esph != NULL) { 525 /* 526 * If we have a tag, it means an IPsec-aware NIC did 527 * the verification for us. Otherwise we need to 528 * check the authentication calculation. 529 */ 530 V_ahstat.ahs_hist[sav->alg_auth]++; 531 if (mtag == NULL) { 532 /* Copy the authenticator from the packet */ 533 m_copydata(m, m->m_pkthdr.len - AH_HMAC_HASHLEN, 534 AH_HMAC_HASHLEN, aalg); 535 536 ptr = (caddr_t) (tc + 1); 537 538 /* Verify authenticator */ 539 if (bcmp(ptr, aalg, AH_HMAC_HASHLEN) != 0) { 540 DPRINTF(("%s: " 541 "authentication hash mismatch for packet in SA %s/%08lx\n", 542 __func__, 543 ipsec_address(&saidx->dst), 544 (u_long) ntohl(sav->spi))); 545 V_espstat.esps_badauth++; 546 error = EACCES; 547 goto bad; 548 } 549 } 550 551 /* Remove trailing authenticator */ 552 m_adj(m, -AH_HMAC_HASHLEN); 553 } 554 555 /* Release the crypto descriptors */ 556 free(tc, M_XDATA), tc = NULL; 557 crypto_freereq(crp), crp = NULL; 558 559 /* 560 * Packet is now decrypted. 561 */ 562 m->m_flags |= M_DECRYPTED; 563 564 /* 565 * Update replay sequence number, if appropriate. 566 */ 567 if (sav->replay) { 568 u_int32_t seq; 569 570 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 571 sizeof (seq), (caddr_t) &seq); 572 if (ipsec_updatereplay(ntohl(seq), sav)) { 573 DPRINTF(("%s: packet replay check for %s\n", __func__, 574 ipsec_logsastr(sav))); 575 V_espstat.esps_replay++; 576 error = ENOBUFS; 577 goto bad; 578 } 579 } 580 581 /* Determine the ESP header length */ 582 if (sav->flags & SADB_X_EXT_OLD) 583 hlen = sizeof (struct esp) + sav->ivlen; 584 else 585 hlen = sizeof (struct newesp) + sav->ivlen; 586 587 /* Remove the ESP header and IV from the mbuf. */ 588 error = m_striphdr(m, skip, hlen); 589 if (error) { 590 V_espstat.esps_hdrops++; 591 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 592 ipsec_address(&sav->sah->saidx.dst), 593 (u_long) ntohl(sav->spi))); 594 goto bad; 595 } 596 597 /* Save the last three bytes of decrypted data */ 598 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 599 600 /* Verify pad length */ 601 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 602 V_espstat.esps_badilen++; 603 DPRINTF(("%s: invalid padding length %d for %u byte packet " 604 "in SA %s/%08lx\n", __func__, 605 lastthree[1], m->m_pkthdr.len - skip, 606 ipsec_address(&sav->sah->saidx.dst), 607 (u_long) ntohl(sav->spi))); 608 error = EINVAL; 609 goto bad; 610 } 611 612 /* Verify correct decryption by checking the last padding bytes */ 613 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 614 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 615 V_espstat.esps_badenc++; 616 DPRINTF(("%s: decryption failed for packet in " 617 "SA %s/%08lx\n", __func__, 618 ipsec_address(&sav->sah->saidx.dst), 619 (u_long) ntohl(sav->spi))); 620 error = EINVAL; 621 goto bad; 622 } 623 } 624 625 /* Trim the mbuf chain to remove trailing authenticator and padding */ 626 m_adj(m, -(lastthree[1] + 2)); 627 628 /* Restore the Next Protocol field */ 629 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 630 631 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag); 632 633 KEY_FREESAV(&sav); 634 return error; 635 bad: 636 if (sav) 637 KEY_FREESAV(&sav); 638 if (m != NULL) 639 m_freem(m); 640 if (tc != NULL) 641 free(tc, M_XDATA); 642 if (crp != NULL) 643 crypto_freereq(crp); 644 return error; 645 } 646 647 /* 648 * ESP output routine, called by ipsec[46]_process_packet(). 649 */ 650 static int 651 esp_output( 652 struct mbuf *m, 653 struct ipsecrequest *isr, 654 struct mbuf **mp, 655 int skip, 656 int protoff 657 ) 658 { 659 INIT_VNET_IPSEC(curvnet); 660 struct enc_xform *espx; 661 struct auth_hash *esph; 662 int hlen, rlen, plen, padding, blks, alen, i, roff; 663 struct mbuf *mo = (struct mbuf *) NULL; 664 struct tdb_crypto *tc; 665 struct secasvar *sav; 666 struct secasindex *saidx; 667 unsigned char *pad; 668 u_int8_t prot; 669 int error, maxpacketsize; 670 671 struct cryptodesc *crde = NULL, *crda = NULL; 672 struct cryptop *crp; 673 674 sav = isr->sav; 675 IPSEC_ASSERT(sav != NULL, ("null SA")); 676 esph = sav->tdb_authalgxform; 677 espx = sav->tdb_encalgxform; 678 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 679 680 if (sav->flags & SADB_X_EXT_OLD) 681 hlen = sizeof (struct esp) + sav->ivlen; 682 else 683 hlen = sizeof (struct newesp) + sav->ivlen; 684 685 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 686 /* 687 * NB: The null encoding transform has a blocksize of 4 688 * so that headers are properly aligned. 689 */ 690 blks = espx->blocksize; /* IV blocksize */ 691 692 /* XXX clamp padding length a la KAME??? */ 693 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 694 plen = rlen + padding; /* Padded payload length. */ 695 696 if (esph) 697 alen = AH_HMAC_HASHLEN; 698 else 699 alen = 0; 700 701 V_espstat.esps_output++; 702 703 saidx = &sav->sah->saidx; 704 /* Check for maximum packet size violations. */ 705 switch (saidx->dst.sa.sa_family) { 706 #ifdef INET 707 case AF_INET: 708 maxpacketsize = IP_MAXPACKET; 709 break; 710 #endif /* INET */ 711 #ifdef INET6 712 case AF_INET6: 713 maxpacketsize = IPV6_MAXPACKET; 714 break; 715 #endif /* INET6 */ 716 default: 717 DPRINTF(("%s: unknown/unsupported protocol " 718 "family %d, SA %s/%08lx\n", __func__, 719 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst), 720 (u_long) ntohl(sav->spi))); 721 V_espstat.esps_nopf++; 722 error = EPFNOSUPPORT; 723 goto bad; 724 } 725 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 726 DPRINTF(("%s: packet in SA %s/%08lx got too big " 727 "(len %u, max len %u)\n", __func__, 728 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi), 729 skip + hlen + rlen + padding + alen, maxpacketsize)); 730 V_espstat.esps_toobig++; 731 error = EMSGSIZE; 732 goto bad; 733 } 734 735 /* Update the counters. */ 736 V_espstat.esps_obytes += m->m_pkthdr.len - skip; 737 738 m = m_unshare(m, M_NOWAIT); 739 if (m == NULL) { 740 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 741 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 742 V_espstat.esps_hdrops++; 743 error = ENOBUFS; 744 goto bad; 745 } 746 747 /* Inject ESP header. */ 748 mo = m_makespace(m, skip, hlen, &roff); 749 if (mo == NULL) { 750 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 751 __func__, hlen, ipsec_address(&saidx->dst), 752 (u_long) ntohl(sav->spi))); 753 V_espstat.esps_hdrops++; /* XXX diffs from openbsd */ 754 error = ENOBUFS; 755 goto bad; 756 } 757 758 /* Initialize ESP header. */ 759 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t)); 760 if (sav->replay) { 761 u_int32_t replay; 762 763 #ifdef REGRESSION 764 /* Emulate replay attack when ipsec_replay is TRUE. */ 765 if (!V_ipsec_replay) 766 #endif 767 sav->replay->count++; 768 replay = htonl(sav->replay->count); 769 bcopy((caddr_t) &replay, 770 mtod(mo, caddr_t) + roff + sizeof(u_int32_t), 771 sizeof(u_int32_t)); 772 } 773 774 /* 775 * Add padding -- better to do it ourselves than use the crypto engine, 776 * although if/when we support compression, we'd have to do that. 777 */ 778 pad = (u_char *) m_pad(m, padding + alen); 779 if (pad == NULL) { 780 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 781 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 782 m = NULL; /* NB: free'd by m_pad */ 783 error = ENOBUFS; 784 goto bad; 785 } 786 787 /* 788 * Add padding: random, zero, or self-describing. 789 * XXX catch unexpected setting 790 */ 791 switch (sav->flags & SADB_X_EXT_PMASK) { 792 case SADB_X_EXT_PRAND: 793 (void) read_random(pad, padding - 2); 794 break; 795 case SADB_X_EXT_PZERO: 796 bzero(pad, padding - 2); 797 break; 798 case SADB_X_EXT_PSEQ: 799 for (i = 0; i < padding - 2; i++) 800 pad[i] = i+1; 801 break; 802 } 803 804 /* Fix padding length and Next Protocol in padding itself. */ 805 pad[padding - 2] = padding - 2; 806 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 807 808 /* Fix Next Protocol in IPv4/IPv6 header. */ 809 prot = IPPROTO_ESP; 810 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 811 812 /* Get crypto descriptors. */ 813 crp = crypto_getreq(esph && espx ? 2 : 1); 814 if (crp == NULL) { 815 DPRINTF(("%s: failed to acquire crypto descriptors\n", 816 __func__)); 817 V_espstat.esps_crypto++; 818 error = ENOBUFS; 819 goto bad; 820 } 821 822 if (espx) { 823 crde = crp->crp_desc; 824 crda = crde->crd_next; 825 826 /* Encryption descriptor. */ 827 crde->crd_skip = skip + hlen; 828 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 829 crde->crd_flags = CRD_F_ENCRYPT; 830 crde->crd_inject = skip + hlen - sav->ivlen; 831 832 /* Encryption operation. */ 833 crde->crd_alg = espx->type; 834 crde->crd_key = sav->key_enc->key_data; 835 crde->crd_klen = _KEYBITS(sav->key_enc); 836 /* XXX Rounds ? */ 837 } else 838 crda = crp->crp_desc; 839 840 /* IPsec-specific opaque crypto info. */ 841 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 842 M_XDATA, M_NOWAIT|M_ZERO); 843 if (tc == NULL) { 844 crypto_freereq(crp); 845 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 846 V_espstat.esps_crypto++; 847 error = ENOBUFS; 848 goto bad; 849 } 850 851 /* Callback parameters */ 852 tc->tc_isr = isr; 853 tc->tc_spi = sav->spi; 854 tc->tc_dst = saidx->dst; 855 tc->tc_proto = saidx->proto; 856 857 /* Crypto operation descriptor. */ 858 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 859 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 860 crp->crp_buf = (caddr_t) m; 861 crp->crp_callback = esp_output_cb; 862 crp->crp_opaque = (caddr_t) tc; 863 crp->crp_sid = sav->tdb_cryptoid; 864 865 if (esph) { 866 /* Authentication descriptor. */ 867 crda->crd_skip = skip; 868 crda->crd_len = m->m_pkthdr.len - (skip + alen); 869 crda->crd_inject = m->m_pkthdr.len - alen; 870 871 /* Authentication operation. */ 872 crda->crd_alg = esph->type; 873 crda->crd_key = sav->key_auth->key_data; 874 crda->crd_klen = _KEYBITS(sav->key_auth); 875 } 876 877 return crypto_dispatch(crp); 878 bad: 879 if (m) 880 m_freem(m); 881 return (error); 882 } 883 884 /* 885 * ESP output callback from the crypto driver. 886 */ 887 static int 888 esp_output_cb(struct cryptop *crp) 889 { 890 INIT_VNET_IPSEC(curvnet); 891 struct tdb_crypto *tc; 892 struct ipsecrequest *isr; 893 struct secasvar *sav; 894 struct mbuf *m; 895 int err, error; 896 897 tc = (struct tdb_crypto *) crp->crp_opaque; 898 IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); 899 m = (struct mbuf *) crp->crp_buf; 900 901 isr = tc->tc_isr; 902 IPSECREQUEST_LOCK(isr); 903 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 904 if (sav == NULL) { 905 V_espstat.esps_notdb++; 906 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 907 __func__, ipsec_address(&tc->tc_dst), 908 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 909 error = ENOBUFS; /*XXX*/ 910 goto bad; 911 } 912 IPSEC_ASSERT(isr->sav == sav, 913 ("SA changed was %p now %p\n", isr->sav, sav)); 914 915 /* Check for crypto errors. */ 916 if (crp->crp_etype) { 917 /* Reset session ID. */ 918 if (sav->tdb_cryptoid != 0) 919 sav->tdb_cryptoid = crp->crp_sid; 920 921 if (crp->crp_etype == EAGAIN) { 922 KEY_FREESAV(&sav); 923 IPSECREQUEST_UNLOCK(isr); 924 error = crypto_dispatch(crp); 925 return error; 926 } 927 928 V_espstat.esps_noxform++; 929 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 930 error = crp->crp_etype; 931 goto bad; 932 } 933 934 /* Shouldn't happen... */ 935 if (m == NULL) { 936 V_espstat.esps_crypto++; 937 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 938 error = EINVAL; 939 goto bad; 940 } 941 V_espstat.esps_hist[sav->alg_enc]++; 942 if (sav->tdb_authalgxform != NULL) 943 V_ahstat.ahs_hist[sav->alg_auth]++; 944 945 /* Release crypto descriptors. */ 946 free(tc, M_XDATA); 947 crypto_freereq(crp); 948 949 #ifdef REGRESSION 950 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 951 if (V_ipsec_integrity) { 952 static unsigned char ipseczeroes[AH_HMAC_HASHLEN]; 953 struct auth_hash *esph; 954 955 /* 956 * Corrupt HMAC if we want to test integrity verification of 957 * the other side. 958 */ 959 esph = sav->tdb_authalgxform; 960 if (esph != NULL) { 961 m_copyback(m, m->m_pkthdr.len - AH_HMAC_HASHLEN, 962 AH_HMAC_HASHLEN, ipseczeroes); 963 } 964 } 965 #endif 966 967 /* NB: m is reclaimed by ipsec_process_done. */ 968 err = ipsec_process_done(m, isr); 969 KEY_FREESAV(&sav); 970 IPSECREQUEST_UNLOCK(isr); 971 return err; 972 bad: 973 if (sav) 974 KEY_FREESAV(&sav); 975 IPSECREQUEST_UNLOCK(isr); 976 if (m) 977 m_freem(m); 978 free(tc, M_XDATA); 979 crypto_freereq(crp); 980 return error; 981 } 982 983 static struct xformsw esp_xformsw = { 984 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 985 esp_init, esp_zeroize, esp_input, 986 esp_output 987 }; 988 989 static void 990 esp_attach(void) 991 { 992 #define MAXIV(xform) \ 993 if (xform.blocksize > V_esp_max_ivlen) \ 994 V_esp_max_ivlen = xform.blocksize \ 995 996 V_esp_max_ivlen = 0; 997 MAXIV(enc_xform_des); /* SADB_EALG_DESCBC */ 998 MAXIV(enc_xform_3des); /* SADB_EALG_3DESCBC */ 999 MAXIV(enc_xform_rijndael128); /* SADB_X_EALG_AES */ 1000 MAXIV(enc_xform_blf); /* SADB_X_EALG_BLOWFISHCBC */ 1001 MAXIV(enc_xform_cast5); /* SADB_X_EALG_CAST128CBC */ 1002 MAXIV(enc_xform_skipjack); /* SADB_X_EALG_SKIPJACK */ 1003 MAXIV(enc_xform_null); /* SADB_EALG_NULL */ 1004 MAXIV(enc_xform_camellia); /* SADB_X_EALG_CAMELLIACBC */ 1005 1006 xform_register(&esp_xformsw); 1007 #undef MAXIV 1008 } 1009 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL); 1010