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 #ifdef VIMAGE_GLOBALS 80 struct espstat espstat; 81 static int esp_max_ivlen; /* max iv length over all algorithms */ 82 int esp_enable; 83 #endif 84 85 SYSCTL_DECL(_net_inet_esp); 86 SYSCTL_V_INT(V_NET, vnet_ipsec,_net_inet_esp, OID_AUTO, 87 esp_enable, CTLFLAG_RW, esp_enable, 0, ""); 88 SYSCTL_V_STRUCT(V_NET, vnet_ipsec, _net_inet_esp, IPSECCTL_STATS, 89 stats, CTLFLAG_RD, espstat, espstat, ""); 90 91 static int esp_input_cb(struct cryptop *op); 92 static int esp_output_cb(struct cryptop *crp); 93 94 /* 95 * NB: this is public for use by the PF_KEY support. 96 * NB: if you add support here; be sure to add code to esp_attach below! 97 */ 98 struct enc_xform * 99 esp_algorithm_lookup(int alg) 100 { 101 if (alg >= ESP_ALG_MAX) 102 return NULL; 103 switch (alg) { 104 case SADB_EALG_DESCBC: 105 return &enc_xform_des; 106 case SADB_EALG_3DESCBC: 107 return &enc_xform_3des; 108 case SADB_X_EALG_AES: 109 return &enc_xform_rijndael128; 110 case SADB_X_EALG_BLOWFISHCBC: 111 return &enc_xform_blf; 112 case SADB_X_EALG_CAST128CBC: 113 return &enc_xform_cast5; 114 case SADB_X_EALG_SKIPJACK: 115 return &enc_xform_skipjack; 116 case SADB_EALG_NULL: 117 return &enc_xform_null; 118 case SADB_X_EALG_CAMELLIACBC: 119 return &enc_xform_camellia; 120 } 121 return NULL; 122 } 123 124 size_t 125 esp_hdrsiz(struct secasvar *sav) 126 { 127 INIT_VNET_IPSEC(curvnet); 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 INIT_VNET_IPSEC(curvnet); 163 struct enc_xform *txform; 164 struct cryptoini cria, crie; 165 int keylen; 166 int error; 167 168 txform = esp_algorithm_lookup(sav->alg_enc); 169 if (txform == NULL) { 170 DPRINTF(("%s: unsupported encryption algorithm %d\n", 171 __func__, sav->alg_enc)); 172 return EINVAL; 173 } 174 if (sav->key_enc == NULL) { 175 DPRINTF(("%s: no encoding key for %s algorithm\n", 176 __func__, txform->name)); 177 return EINVAL; 178 } 179 if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) { 180 DPRINTF(("%s: 4-byte IV not supported with protocol\n", 181 __func__)); 182 return EINVAL; 183 } 184 keylen = _KEYLEN(sav->key_enc); 185 if (txform->minkey > keylen || keylen > txform->maxkey) { 186 DPRINTF(("%s: invalid key length %u, must be in the range " 187 "[%u..%u] for algorithm %s\n", __func__, 188 keylen, txform->minkey, txform->maxkey, 189 txform->name)); 190 return EINVAL; 191 } 192 193 /* 194 * NB: The null xform needs a non-zero blocksize to keep the 195 * crypto code happy but if we use it to set ivlen then 196 * the ESP header will be processed incorrectly. The 197 * compromise is to force it to zero here. 198 */ 199 sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize); 200 sav->iv = (caddr_t) malloc(sav->ivlen, M_XDATA, M_WAITOK); 201 if (sav->iv == NULL) { 202 DPRINTF(("%s: no memory for IV\n", __func__)); 203 return EINVAL; 204 } 205 key_randomfill(sav->iv, sav->ivlen); /*XXX*/ 206 207 /* 208 * Setup AH-related state. 209 */ 210 if (sav->alg_auth != 0) { 211 error = ah_init0(sav, xsp, &cria); 212 if (error) 213 return error; 214 } 215 216 /* NB: override anything set in ah_init0 */ 217 sav->tdb_xform = xsp; 218 sav->tdb_encalgxform = txform; 219 220 /* Initialize crypto session. */ 221 bzero(&crie, sizeof (crie)); 222 crie.cri_alg = sav->tdb_encalgxform->type; 223 crie.cri_klen = _KEYBITS(sav->key_enc); 224 crie.cri_key = sav->key_enc->key_data; 225 /* XXX Rounds ? */ 226 227 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 228 /* init both auth & enc */ 229 crie.cri_next = &cria; 230 error = crypto_newsession(&sav->tdb_cryptoid, 231 &crie, V_crypto_support); 232 } else if (sav->tdb_encalgxform) { 233 error = crypto_newsession(&sav->tdb_cryptoid, 234 &crie, V_crypto_support); 235 } else if (sav->tdb_authalgxform) { 236 error = crypto_newsession(&sav->tdb_cryptoid, 237 &cria, V_crypto_support); 238 } else { 239 /* XXX cannot happen? */ 240 DPRINTF(("%s: no encoding OR authentication xform!\n", 241 __func__)); 242 error = EINVAL; 243 } 244 return error; 245 } 246 247 /* 248 * Paranoia. 249 */ 250 static int 251 esp_zeroize(struct secasvar *sav) 252 { 253 /* NB: ah_zerorize free's the crypto session state */ 254 int error = ah_zeroize(sav); 255 256 if (sav->key_enc) 257 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc)); 258 if (sav->iv) { 259 free(sav->iv, M_XDATA); 260 sav->iv = NULL; 261 } 262 sav->tdb_encalgxform = NULL; 263 sav->tdb_xform = NULL; 264 return error; 265 } 266 267 /* 268 * ESP input processing, called (eventually) through the protocol switch. 269 */ 270 static int 271 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 272 { 273 INIT_VNET_IPSEC(curvnet); 274 struct auth_hash *esph; 275 struct enc_xform *espx; 276 struct tdb_ident *tdbi; 277 struct tdb_crypto *tc; 278 int plen, alen, hlen; 279 struct m_tag *mtag; 280 struct newesp *esp; 281 282 struct cryptodesc *crde; 283 struct cryptop *crp; 284 285 IPSEC_ASSERT(sav != NULL, ("null SA")); 286 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); 287 IPSEC_ASSERT((skip&3) == 0 && (m->m_pkthdr.len&3) == 0, 288 ("misaligned packet, skip %u pkt len %u", 289 skip, m->m_pkthdr.len)); 290 291 /* XXX don't pullup, just copy header */ 292 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 293 294 esph = sav->tdb_authalgxform; 295 espx = sav->tdb_encalgxform; 296 297 /* Determine the ESP header length */ 298 if (sav->flags & SADB_X_EXT_OLD) 299 hlen = sizeof (struct esp) + sav->ivlen; 300 else 301 hlen = sizeof (struct newesp) + sav->ivlen; 302 /* Authenticator hash size */ 303 alen = esph ? AH_HMAC_HASHLEN : 0; 304 305 /* 306 * Verify payload length is multiple of encryption algorithm 307 * block size. 308 * 309 * NB: This works for the null algorithm because the blocksize 310 * is 4 and all packets must be 4-byte aligned regardless 311 * of the algorithm. 312 */ 313 plen = m->m_pkthdr.len - (skip + hlen + alen); 314 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 315 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 316 " SA %s/%08lx\n", __func__, 317 plen, espx->blocksize, 318 ipsec_address(&sav->sah->saidx.dst), 319 (u_long) ntohl(sav->spi))); 320 V_espstat.esps_badilen++; 321 m_freem(m); 322 return EINVAL; 323 } 324 325 /* 326 * Check sequence number. 327 */ 328 if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) { 329 DPRINTF(("%s: packet replay check for %s\n", __func__, 330 ipsec_logsastr(sav))); /*XXX*/ 331 V_espstat.esps_replay++; 332 m_freem(m); 333 return ENOBUFS; /*XXX*/ 334 } 335 336 /* Update the counters */ 337 V_espstat.esps_ibytes += m->m_pkthdr.len - (skip + hlen + alen); 338 339 /* Find out if we've already done crypto */ 340 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL); 341 mtag != NULL; 342 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) { 343 tdbi = (struct tdb_ident *) (mtag + 1); 344 if (tdbi->proto == sav->sah->saidx.proto && 345 tdbi->spi == sav->spi && 346 !bcmp(&tdbi->dst, &sav->sah->saidx.dst, 347 sizeof(union sockaddr_union))) 348 break; 349 } 350 351 /* Get crypto descriptors */ 352 crp = crypto_getreq(esph && espx ? 2 : 1); 353 if (crp == NULL) { 354 DPRINTF(("%s: failed to acquire crypto descriptors\n", 355 __func__)); 356 V_espstat.esps_crypto++; 357 m_freem(m); 358 return ENOBUFS; 359 } 360 361 /* Get IPsec-specific opaque pointer */ 362 if (esph == NULL || mtag != NULL) 363 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 364 M_XDATA, M_NOWAIT|M_ZERO); 365 else 366 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen, 367 M_XDATA, M_NOWAIT|M_ZERO); 368 if (tc == NULL) { 369 crypto_freereq(crp); 370 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 371 V_espstat.esps_crypto++; 372 m_freem(m); 373 return ENOBUFS; 374 } 375 376 tc->tc_ptr = (caddr_t) mtag; 377 378 if (esph) { 379 struct cryptodesc *crda = crp->crp_desc; 380 381 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor")); 382 383 /* Authentication descriptor */ 384 crda->crd_skip = skip; 385 crda->crd_len = m->m_pkthdr.len - (skip + alen); 386 crda->crd_inject = m->m_pkthdr.len - alen; 387 388 crda->crd_alg = esph->type; 389 crda->crd_key = sav->key_auth->key_data; 390 crda->crd_klen = _KEYBITS(sav->key_auth); 391 392 /* Copy the authenticator */ 393 if (mtag == NULL) 394 m_copydata(m, m->m_pkthdr.len - alen, alen, 395 (caddr_t) (tc + 1)); 396 397 /* Chain authentication request */ 398 crde = crda->crd_next; 399 } else { 400 crde = crp->crp_desc; 401 } 402 403 /* Crypto operation descriptor */ 404 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 405 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 406 crp->crp_buf = (caddr_t) m; 407 crp->crp_callback = esp_input_cb; 408 crp->crp_sid = sav->tdb_cryptoid; 409 crp->crp_opaque = (caddr_t) tc; 410 411 /* These are passed as-is to the callback */ 412 tc->tc_spi = sav->spi; 413 tc->tc_dst = sav->sah->saidx.dst; 414 tc->tc_proto = sav->sah->saidx.proto; 415 tc->tc_protoff = protoff; 416 tc->tc_skip = skip; 417 418 /* Decryption descriptor */ 419 if (espx) { 420 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor")); 421 crde->crd_skip = skip + hlen; 422 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 423 crde->crd_inject = skip + hlen - sav->ivlen; 424 425 crde->crd_alg = espx->type; 426 crde->crd_key = sav->key_enc->key_data; 427 crde->crd_klen = _KEYBITS(sav->key_enc); 428 /* XXX Rounds ? */ 429 } 430 431 if (mtag == NULL) 432 return crypto_dispatch(crp); 433 else 434 return esp_input_cb(crp); 435 } 436 437 #ifdef INET6 438 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \ 439 if (saidx->dst.sa.sa_family == AF_INET6) { \ 440 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \ 441 } else { \ 442 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \ 443 } \ 444 } while (0) 445 #else 446 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \ 447 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag)) 448 #endif 449 450 /* 451 * ESP input callback from the crypto driver. 452 */ 453 static int 454 esp_input_cb(struct cryptop *crp) 455 { 456 INIT_VNET_IPSEC(curvnet); 457 u_int8_t lastthree[3], aalg[AH_HMAC_HASHLEN]; 458 int hlen, skip, protoff, error; 459 struct mbuf *m; 460 struct cryptodesc *crd; 461 struct auth_hash *esph; 462 struct enc_xform *espx; 463 struct tdb_crypto *tc; 464 struct m_tag *mtag; 465 struct secasvar *sav; 466 struct secasindex *saidx; 467 caddr_t ptr; 468 469 crd = crp->crp_desc; 470 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!")); 471 472 tc = (struct tdb_crypto *) crp->crp_opaque; 473 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!")); 474 skip = tc->tc_skip; 475 protoff = tc->tc_protoff; 476 mtag = (struct m_tag *) tc->tc_ptr; 477 m = (struct mbuf *) crp->crp_buf; 478 479 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 480 if (sav == NULL) { 481 V_espstat.esps_notdb++; 482 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 483 __func__, ipsec_address(&tc->tc_dst), 484 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 485 error = ENOBUFS; /*XXX*/ 486 goto bad; 487 } 488 489 saidx = &sav->sah->saidx; 490 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 491 saidx->dst.sa.sa_family == AF_INET6, 492 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 493 494 esph = sav->tdb_authalgxform; 495 espx = sav->tdb_encalgxform; 496 497 /* Check for crypto errors */ 498 if (crp->crp_etype) { 499 /* Reset the session ID */ 500 if (sav->tdb_cryptoid != 0) 501 sav->tdb_cryptoid = crp->crp_sid; 502 503 if (crp->crp_etype == EAGAIN) { 504 KEY_FREESAV(&sav); 505 error = crypto_dispatch(crp); 506 return error; 507 } 508 509 V_espstat.esps_noxform++; 510 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 511 error = crp->crp_etype; 512 goto bad; 513 } 514 515 /* Shouldn't happen... */ 516 if (m == NULL) { 517 V_espstat.esps_crypto++; 518 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 519 error = EINVAL; 520 goto bad; 521 } 522 V_espstat.esps_hist[sav->alg_enc]++; 523 524 /* If authentication was performed, check now. */ 525 if (esph != NULL) { 526 /* 527 * If we have a tag, it means an IPsec-aware NIC did 528 * the verification for us. Otherwise we need to 529 * check the authentication calculation. 530 */ 531 V_ahstat.ahs_hist[sav->alg_auth]++; 532 if (mtag == NULL) { 533 /* Copy the authenticator from the packet */ 534 m_copydata(m, m->m_pkthdr.len - AH_HMAC_HASHLEN, 535 AH_HMAC_HASHLEN, aalg); 536 537 ptr = (caddr_t) (tc + 1); 538 539 /* Verify authenticator */ 540 if (bcmp(ptr, aalg, AH_HMAC_HASHLEN) != 0) { 541 DPRINTF(("%s: " 542 "authentication hash mismatch for packet in SA %s/%08lx\n", 543 __func__, 544 ipsec_address(&saidx->dst), 545 (u_long) ntohl(sav->spi))); 546 V_espstat.esps_badauth++; 547 error = EACCES; 548 goto bad; 549 } 550 } 551 552 /* Remove trailing authenticator */ 553 m_adj(m, -AH_HMAC_HASHLEN); 554 } 555 556 /* Release the crypto descriptors */ 557 free(tc, M_XDATA), tc = NULL; 558 crypto_freereq(crp), crp = NULL; 559 560 /* 561 * Packet is now decrypted. 562 */ 563 m->m_flags |= M_DECRYPTED; 564 565 /* 566 * Update replay sequence number, if appropriate. 567 */ 568 if (sav->replay) { 569 u_int32_t seq; 570 571 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 572 sizeof (seq), (caddr_t) &seq); 573 if (ipsec_updatereplay(ntohl(seq), sav)) { 574 DPRINTF(("%s: packet replay check for %s\n", __func__, 575 ipsec_logsastr(sav))); 576 V_espstat.esps_replay++; 577 error = ENOBUFS; 578 goto bad; 579 } 580 } 581 582 /* Determine the ESP header length */ 583 if (sav->flags & SADB_X_EXT_OLD) 584 hlen = sizeof (struct esp) + sav->ivlen; 585 else 586 hlen = sizeof (struct newesp) + sav->ivlen; 587 588 /* Remove the ESP header and IV from the mbuf. */ 589 error = m_striphdr(m, skip, hlen); 590 if (error) { 591 V_espstat.esps_hdrops++; 592 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 593 ipsec_address(&sav->sah->saidx.dst), 594 (u_long) ntohl(sav->spi))); 595 goto bad; 596 } 597 598 /* Save the last three bytes of decrypted data */ 599 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 600 601 /* Verify pad length */ 602 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 603 V_espstat.esps_badilen++; 604 DPRINTF(("%s: invalid padding length %d for %u byte packet " 605 "in SA %s/%08lx\n", __func__, 606 lastthree[1], m->m_pkthdr.len - skip, 607 ipsec_address(&sav->sah->saidx.dst), 608 (u_long) ntohl(sav->spi))); 609 error = EINVAL; 610 goto bad; 611 } 612 613 /* Verify correct decryption by checking the last padding bytes */ 614 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 615 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 616 V_espstat.esps_badenc++; 617 DPRINTF(("%s: decryption failed for packet in " 618 "SA %s/%08lx\n", __func__, 619 ipsec_address(&sav->sah->saidx.dst), 620 (u_long) ntohl(sav->spi))); 621 error = EINVAL; 622 goto bad; 623 } 624 } 625 626 /* Trim the mbuf chain to remove trailing authenticator and padding */ 627 m_adj(m, -(lastthree[1] + 2)); 628 629 /* Restore the Next Protocol field */ 630 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 631 632 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag); 633 634 KEY_FREESAV(&sav); 635 return error; 636 bad: 637 if (sav) 638 KEY_FREESAV(&sav); 639 if (m != NULL) 640 m_freem(m); 641 if (tc != NULL) 642 free(tc, M_XDATA); 643 if (crp != NULL) 644 crypto_freereq(crp); 645 return error; 646 } 647 648 /* 649 * ESP output routine, called by ipsec[46]_process_packet(). 650 */ 651 static int 652 esp_output( 653 struct mbuf *m, 654 struct ipsecrequest *isr, 655 struct mbuf **mp, 656 int skip, 657 int protoff 658 ) 659 { 660 INIT_VNET_IPSEC(curvnet); 661 struct enc_xform *espx; 662 struct auth_hash *esph; 663 int hlen, rlen, plen, padding, blks, alen, i, roff; 664 struct mbuf *mo = (struct mbuf *) NULL; 665 struct tdb_crypto *tc; 666 struct secasvar *sav; 667 struct secasindex *saidx; 668 unsigned char *pad; 669 u_int8_t prot; 670 int error, maxpacketsize; 671 672 struct cryptodesc *crde = NULL, *crda = NULL; 673 struct cryptop *crp; 674 675 sav = isr->sav; 676 IPSEC_ASSERT(sav != NULL, ("null SA")); 677 esph = sav->tdb_authalgxform; 678 espx = sav->tdb_encalgxform; 679 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 680 681 if (sav->flags & SADB_X_EXT_OLD) 682 hlen = sizeof (struct esp) + sav->ivlen; 683 else 684 hlen = sizeof (struct newesp) + sav->ivlen; 685 686 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 687 /* 688 * NB: The null encoding transform has a blocksize of 4 689 * so that headers are properly aligned. 690 */ 691 blks = espx->blocksize; /* IV blocksize */ 692 693 /* XXX clamp padding length a la KAME??? */ 694 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 695 plen = rlen + padding; /* Padded payload length. */ 696 697 if (esph) 698 alen = AH_HMAC_HASHLEN; 699 else 700 alen = 0; 701 702 V_espstat.esps_output++; 703 704 saidx = &sav->sah->saidx; 705 /* Check for maximum packet size violations. */ 706 switch (saidx->dst.sa.sa_family) { 707 #ifdef INET 708 case AF_INET: 709 maxpacketsize = IP_MAXPACKET; 710 break; 711 #endif /* INET */ 712 #ifdef INET6 713 case AF_INET6: 714 maxpacketsize = IPV6_MAXPACKET; 715 break; 716 #endif /* INET6 */ 717 default: 718 DPRINTF(("%s: unknown/unsupported protocol " 719 "family %d, SA %s/%08lx\n", __func__, 720 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst), 721 (u_long) ntohl(sav->spi))); 722 V_espstat.esps_nopf++; 723 error = EPFNOSUPPORT; 724 goto bad; 725 } 726 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 727 DPRINTF(("%s: packet in SA %s/%08lx got too big " 728 "(len %u, max len %u)\n", __func__, 729 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi), 730 skip + hlen + rlen + padding + alen, maxpacketsize)); 731 V_espstat.esps_toobig++; 732 error = EMSGSIZE; 733 goto bad; 734 } 735 736 /* Update the counters. */ 737 V_espstat.esps_obytes += m->m_pkthdr.len - skip; 738 739 m = m_unshare(m, M_NOWAIT); 740 if (m == NULL) { 741 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 742 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 743 V_espstat.esps_hdrops++; 744 error = ENOBUFS; 745 goto bad; 746 } 747 748 /* Inject ESP header. */ 749 mo = m_makespace(m, skip, hlen, &roff); 750 if (mo == NULL) { 751 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 752 __func__, hlen, ipsec_address(&saidx->dst), 753 (u_long) ntohl(sav->spi))); 754 V_espstat.esps_hdrops++; /* XXX diffs from openbsd */ 755 error = ENOBUFS; 756 goto bad; 757 } 758 759 /* Initialize ESP header. */ 760 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t)); 761 if (sav->replay) { 762 u_int32_t replay; 763 764 #ifdef REGRESSION 765 /* Emulate replay attack when ipsec_replay is TRUE. */ 766 if (!V_ipsec_replay) 767 #endif 768 sav->replay->count++; 769 replay = htonl(sav->replay->count); 770 bcopy((caddr_t) &replay, 771 mtod(mo, caddr_t) + roff + sizeof(u_int32_t), 772 sizeof(u_int32_t)); 773 } 774 775 /* 776 * Add padding -- better to do it ourselves than use the crypto engine, 777 * although if/when we support compression, we'd have to do that. 778 */ 779 pad = (u_char *) m_pad(m, padding + alen); 780 if (pad == NULL) { 781 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 782 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 783 m = NULL; /* NB: free'd by m_pad */ 784 error = ENOBUFS; 785 goto bad; 786 } 787 788 /* 789 * Add padding: random, zero, or self-describing. 790 * XXX catch unexpected setting 791 */ 792 switch (sav->flags & SADB_X_EXT_PMASK) { 793 case SADB_X_EXT_PRAND: 794 (void) read_random(pad, padding - 2); 795 break; 796 case SADB_X_EXT_PZERO: 797 bzero(pad, padding - 2); 798 break; 799 case SADB_X_EXT_PSEQ: 800 for (i = 0; i < padding - 2; i++) 801 pad[i] = i+1; 802 break; 803 } 804 805 /* Fix padding length and Next Protocol in padding itself. */ 806 pad[padding - 2] = padding - 2; 807 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 808 809 /* Fix Next Protocol in IPv4/IPv6 header. */ 810 prot = IPPROTO_ESP; 811 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 812 813 /* Get crypto descriptors. */ 814 crp = crypto_getreq(esph && espx ? 2 : 1); 815 if (crp == NULL) { 816 DPRINTF(("%s: failed to acquire crypto descriptors\n", 817 __func__)); 818 V_espstat.esps_crypto++; 819 error = ENOBUFS; 820 goto bad; 821 } 822 823 if (espx) { 824 crde = crp->crp_desc; 825 crda = crde->crd_next; 826 827 /* Encryption descriptor. */ 828 crde->crd_skip = skip + hlen; 829 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 830 crde->crd_flags = CRD_F_ENCRYPT; 831 crde->crd_inject = skip + hlen - sav->ivlen; 832 833 /* Encryption operation. */ 834 crde->crd_alg = espx->type; 835 crde->crd_key = sav->key_enc->key_data; 836 crde->crd_klen = _KEYBITS(sav->key_enc); 837 /* XXX Rounds ? */ 838 } else 839 crda = crp->crp_desc; 840 841 /* IPsec-specific opaque crypto info. */ 842 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 843 M_XDATA, M_NOWAIT|M_ZERO); 844 if (tc == NULL) { 845 crypto_freereq(crp); 846 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 847 V_espstat.esps_crypto++; 848 error = ENOBUFS; 849 goto bad; 850 } 851 852 /* Callback parameters */ 853 tc->tc_isr = isr; 854 tc->tc_spi = sav->spi; 855 tc->tc_dst = saidx->dst; 856 tc->tc_proto = saidx->proto; 857 858 /* Crypto operation descriptor. */ 859 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 860 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 861 crp->crp_buf = (caddr_t) m; 862 crp->crp_callback = esp_output_cb; 863 crp->crp_opaque = (caddr_t) tc; 864 crp->crp_sid = sav->tdb_cryptoid; 865 866 if (esph) { 867 /* Authentication descriptor. */ 868 crda->crd_skip = skip; 869 crda->crd_len = m->m_pkthdr.len - (skip + alen); 870 crda->crd_inject = m->m_pkthdr.len - alen; 871 872 /* Authentication operation. */ 873 crda->crd_alg = esph->type; 874 crda->crd_key = sav->key_auth->key_data; 875 crda->crd_klen = _KEYBITS(sav->key_auth); 876 } 877 878 return crypto_dispatch(crp); 879 bad: 880 if (m) 881 m_freem(m); 882 return (error); 883 } 884 885 /* 886 * ESP output callback from the crypto driver. 887 */ 888 static int 889 esp_output_cb(struct cryptop *crp) 890 { 891 INIT_VNET_IPSEC(curvnet); 892 struct tdb_crypto *tc; 893 struct ipsecrequest *isr; 894 struct secasvar *sav; 895 struct mbuf *m; 896 int err, error; 897 898 tc = (struct tdb_crypto *) crp->crp_opaque; 899 IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); 900 m = (struct mbuf *) crp->crp_buf; 901 902 isr = tc->tc_isr; 903 IPSECREQUEST_LOCK(isr); 904 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 905 if (sav == NULL) { 906 V_espstat.esps_notdb++; 907 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 908 __func__, ipsec_address(&tc->tc_dst), 909 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 910 error = ENOBUFS; /*XXX*/ 911 goto bad; 912 } 913 IPSEC_ASSERT(isr->sav == sav, 914 ("SA changed was %p now %p\n", isr->sav, sav)); 915 916 /* Check for crypto errors. */ 917 if (crp->crp_etype) { 918 /* Reset session ID. */ 919 if (sav->tdb_cryptoid != 0) 920 sav->tdb_cryptoid = crp->crp_sid; 921 922 if (crp->crp_etype == EAGAIN) { 923 KEY_FREESAV(&sav); 924 IPSECREQUEST_UNLOCK(isr); 925 error = crypto_dispatch(crp); 926 return error; 927 } 928 929 V_espstat.esps_noxform++; 930 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 931 error = crp->crp_etype; 932 goto bad; 933 } 934 935 /* Shouldn't happen... */ 936 if (m == NULL) { 937 V_espstat.esps_crypto++; 938 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 939 error = EINVAL; 940 goto bad; 941 } 942 V_espstat.esps_hist[sav->alg_enc]++; 943 if (sav->tdb_authalgxform != NULL) 944 V_ahstat.ahs_hist[sav->alg_auth]++; 945 946 /* Release crypto descriptors. */ 947 free(tc, M_XDATA); 948 crypto_freereq(crp); 949 950 #ifdef REGRESSION 951 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 952 if (V_ipsec_integrity) { 953 static unsigned char ipseczeroes[AH_HMAC_HASHLEN]; 954 struct auth_hash *esph; 955 956 /* 957 * Corrupt HMAC if we want to test integrity verification of 958 * the other side. 959 */ 960 esph = sav->tdb_authalgxform; 961 if (esph != NULL) { 962 m_copyback(m, m->m_pkthdr.len - AH_HMAC_HASHLEN, 963 AH_HMAC_HASHLEN, ipseczeroes); 964 } 965 } 966 #endif 967 968 /* NB: m is reclaimed by ipsec_process_done. */ 969 err = ipsec_process_done(m, isr); 970 KEY_FREESAV(&sav); 971 IPSECREQUEST_UNLOCK(isr); 972 return err; 973 bad: 974 if (sav) 975 KEY_FREESAV(&sav); 976 IPSECREQUEST_UNLOCK(isr); 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 #define MAXIV(xform) \ 994 if (xform.blocksize > V_esp_max_ivlen) \ 995 V_esp_max_ivlen = xform.blocksize \ 996 997 V_esp_enable = 1; 998 V_esp_max_ivlen = 0; 999 1000 MAXIV(enc_xform_des); /* SADB_EALG_DESCBC */ 1001 MAXIV(enc_xform_3des); /* SADB_EALG_3DESCBC */ 1002 MAXIV(enc_xform_rijndael128); /* SADB_X_EALG_AES */ 1003 MAXIV(enc_xform_blf); /* SADB_X_EALG_BLOWFISHCBC */ 1004 MAXIV(enc_xform_cast5); /* SADB_X_EALG_CAST128CBC */ 1005 MAXIV(enc_xform_skipjack); /* SADB_X_EALG_SKIPJACK */ 1006 MAXIV(enc_xform_null); /* SADB_EALG_NULL */ 1007 MAXIV(enc_xform_camellia); /* SADB_X_EALG_CAMELLIACBC */ 1008 1009 xform_register(&esp_xformsw); 1010 #undef MAXIV 1011 } 1012 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL); 1013