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 52 #include <netinet/in.h> 53 #include <netinet/in_systm.h> 54 #include <netinet/ip.h> 55 #include <netinet/ip_ecn.h> 56 #include <netinet/ip6.h> 57 58 #include <net/route.h> 59 #include <netipsec/ipsec.h> 60 #include <netipsec/ah.h> 61 #include <netipsec/ah_var.h> 62 #include <netipsec/esp.h> 63 #include <netipsec/esp_var.h> 64 #include <netipsec/xform.h> 65 66 #ifdef INET6 67 #include <netinet6/ip6_var.h> 68 #include <netipsec/ipsec6.h> 69 #include <netinet6/ip6_ecn.h> 70 #endif 71 72 #include <netipsec/key.h> 73 #include <netipsec/key_debug.h> 74 75 #include <opencrypto/cryptodev.h> 76 #include <opencrypto/xform.h> 77 78 int esp_enable = 1; 79 struct espstat espstat; 80 81 SYSCTL_DECL(_net_inet_esp); 82 SYSCTL_INT(_net_inet_esp, OID_AUTO, 83 esp_enable, CTLFLAG_RW, &esp_enable, 0, ""); 84 SYSCTL_STRUCT(_net_inet_esp, IPSECCTL_STATS, 85 stats, CTLFLAG_RD, &espstat, espstat, ""); 86 87 static int esp_max_ivlen; /* max iv length over all algorithms */ 88 89 static int esp_input_cb(struct cryptop *op); 90 static int esp_output_cb(struct cryptop *crp); 91 92 /* 93 * NB: this is public for use by the PF_KEY support. 94 * NB: if you add support here; be sure to add code to esp_attach below! 95 */ 96 struct enc_xform * 97 esp_algorithm_lookup(int alg) 98 { 99 if (alg >= ESP_ALG_MAX) 100 return NULL; 101 switch (alg) { 102 case SADB_EALG_DESCBC: 103 return &enc_xform_des; 104 case SADB_EALG_3DESCBC: 105 return &enc_xform_3des; 106 case SADB_X_EALG_AES: 107 return &enc_xform_rijndael128; 108 case SADB_X_EALG_BLOWFISHCBC: 109 return &enc_xform_blf; 110 case SADB_X_EALG_CAST128CBC: 111 return &enc_xform_cast5; 112 case SADB_X_EALG_SKIPJACK: 113 return &enc_xform_skipjack; 114 case SADB_EALG_NULL: 115 return &enc_xform_null; 116 case SADB_X_EALG_CAMELLIACBC: 117 return &enc_xform_camellia; 118 } 119 return NULL; 120 } 121 122 size_t 123 esp_hdrsiz(struct secasvar *sav) 124 { 125 size_t size; 126 127 if (sav != NULL) { 128 /*XXX not right for null algorithm--does it matter??*/ 129 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 130 ("SA with null xform")); 131 if (sav->flags & SADB_X_EXT_OLD) 132 size = sizeof (struct esp); 133 else 134 size = sizeof (struct newesp); 135 size += sav->tdb_encalgxform->blocksize + 9; 136 /*XXX need alg check???*/ 137 if (sav->tdb_authalgxform != NULL && sav->replay) 138 size += ah_hdrsiz(sav); 139 } else { 140 /* 141 * base header size 142 * + max iv length for CBC mode 143 * + max pad length 144 * + sizeof (pad length field) 145 * + sizeof (next header field) 146 * + max icv supported. 147 */ 148 size = sizeof (struct newesp) + esp_max_ivlen + 9 + 16; 149 } 150 return size; 151 } 152 153 /* 154 * esp_init() is called when an SPI is being set up. 155 */ 156 static int 157 esp_init(struct secasvar *sav, struct xformsw *xsp) 158 { 159 struct enc_xform *txform; 160 struct cryptoini cria, crie; 161 int keylen; 162 int error; 163 164 txform = esp_algorithm_lookup(sav->alg_enc); 165 if (txform == NULL) { 166 DPRINTF(("%s: unsupported encryption algorithm %d\n", 167 __func__, sav->alg_enc)); 168 return EINVAL; 169 } 170 if (sav->key_enc == NULL) { 171 DPRINTF(("%s: no encoding key for %s algorithm\n", 172 __func__, txform->name)); 173 return EINVAL; 174 } 175 if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) { 176 DPRINTF(("%s: 4-byte IV not supported with protocol\n", 177 __func__)); 178 return EINVAL; 179 } 180 keylen = _KEYLEN(sav->key_enc); 181 if (txform->minkey > keylen || keylen > txform->maxkey) { 182 DPRINTF(("%s: invalid key length %u, must be in the range " 183 "[%u..%u] for algorithm %s\n", __func__, 184 keylen, txform->minkey, txform->maxkey, 185 txform->name)); 186 return EINVAL; 187 } 188 189 /* 190 * NB: The null xform needs a non-zero blocksize to keep the 191 * crypto code happy but if we use it to set ivlen then 192 * the ESP header will be processed incorrectly. The 193 * compromise is to force it to zero here. 194 */ 195 sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize); 196 sav->iv = (caddr_t) malloc(sav->ivlen, M_XDATA, M_WAITOK); 197 if (sav->iv == NULL) { 198 DPRINTF(("%s: no memory for IV\n", __func__)); 199 return EINVAL; 200 } 201 key_randomfill(sav->iv, sav->ivlen); /*XXX*/ 202 203 /* 204 * Setup AH-related state. 205 */ 206 if (sav->alg_auth != 0) { 207 error = ah_init0(sav, xsp, &cria); 208 if (error) 209 return error; 210 } 211 212 /* NB: override anything set in ah_init0 */ 213 sav->tdb_xform = xsp; 214 sav->tdb_encalgxform = txform; 215 216 /* Initialize crypto session. */ 217 bzero(&crie, sizeof (crie)); 218 crie.cri_alg = sav->tdb_encalgxform->type; 219 crie.cri_klen = _KEYBITS(sav->key_enc); 220 crie.cri_key = sav->key_enc->key_data; 221 /* XXX Rounds ? */ 222 223 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 224 /* init both auth & enc */ 225 crie.cri_next = &cria; 226 error = crypto_newsession(&sav->tdb_cryptoid, 227 &crie, crypto_support); 228 } else if (sav->tdb_encalgxform) { 229 error = crypto_newsession(&sav->tdb_cryptoid, 230 &crie, crypto_support); 231 } else if (sav->tdb_authalgxform) { 232 error = crypto_newsession(&sav->tdb_cryptoid, 233 &cria, crypto_support); 234 } else { 235 /* XXX cannot happen? */ 236 DPRINTF(("%s: no encoding OR authentication xform!\n", 237 __func__)); 238 error = EINVAL; 239 } 240 return error; 241 } 242 243 /* 244 * Paranoia. 245 */ 246 static int 247 esp_zeroize(struct secasvar *sav) 248 { 249 /* NB: ah_zerorize free's the crypto session state */ 250 int error = ah_zeroize(sav); 251 252 if (sav->key_enc) 253 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc)); 254 if (sav->iv) { 255 free(sav->iv, M_XDATA); 256 sav->iv = NULL; 257 } 258 sav->tdb_encalgxform = NULL; 259 sav->tdb_xform = NULL; 260 return error; 261 } 262 263 /* 264 * ESP input processing, called (eventually) through the protocol switch. 265 */ 266 static int 267 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 268 { 269 struct auth_hash *esph; 270 struct enc_xform *espx; 271 struct tdb_ident *tdbi; 272 struct tdb_crypto *tc; 273 int plen, alen, hlen; 274 struct m_tag *mtag; 275 struct newesp *esp; 276 277 struct cryptodesc *crde; 278 struct cryptop *crp; 279 280 IPSEC_SPLASSERT_SOFTNET(__func__); 281 282 IPSEC_ASSERT(sav != NULL, ("null SA")); 283 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); 284 IPSEC_ASSERT((skip&3) == 0 && (m->m_pkthdr.len&3) == 0, 285 ("misaligned packet, skip %u pkt len %u", 286 skip, m->m_pkthdr.len)); 287 288 /* XXX don't pullup, just copy header */ 289 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 290 291 esph = sav->tdb_authalgxform; 292 espx = sav->tdb_encalgxform; 293 294 /* Determine the ESP header length */ 295 if (sav->flags & SADB_X_EXT_OLD) 296 hlen = sizeof (struct esp) + sav->ivlen; 297 else 298 hlen = sizeof (struct newesp) + sav->ivlen; 299 /* Authenticator hash size */ 300 alen = esph ? AH_HMAC_HASHLEN : 0; 301 302 /* 303 * Verify payload length is multiple of encryption algorithm 304 * block size. 305 * 306 * NB: This works for the null algorithm because the blocksize 307 * is 4 and all packets must be 4-byte aligned regardless 308 * of the algorithm. 309 */ 310 plen = m->m_pkthdr.len - (skip + hlen + alen); 311 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 312 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 313 " SA %s/%08lx\n", __func__, 314 plen, espx->blocksize, 315 ipsec_address(&sav->sah->saidx.dst), 316 (u_long) ntohl(sav->spi))); 317 espstat.esps_badilen++; 318 m_freem(m); 319 return EINVAL; 320 } 321 322 /* 323 * Check sequence number. 324 */ 325 if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) { 326 DPRINTF(("%s: packet replay check for %s\n", __func__, 327 ipsec_logsastr(sav))); /*XXX*/ 328 espstat.esps_replay++; 329 m_freem(m); 330 return ENOBUFS; /*XXX*/ 331 } 332 333 /* Update the counters */ 334 espstat.esps_ibytes += m->m_pkthdr.len - (skip + hlen + alen); 335 336 /* Find out if we've already done crypto */ 337 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL); 338 mtag != NULL; 339 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) { 340 tdbi = (struct tdb_ident *) (mtag + 1); 341 if (tdbi->proto == sav->sah->saidx.proto && 342 tdbi->spi == sav->spi && 343 !bcmp(&tdbi->dst, &sav->sah->saidx.dst, 344 sizeof(union sockaddr_union))) 345 break; 346 } 347 348 /* Get crypto descriptors */ 349 crp = crypto_getreq(esph && espx ? 2 : 1); 350 if (crp == NULL) { 351 DPRINTF(("%s: failed to acquire crypto descriptors\n", 352 __func__)); 353 espstat.esps_crypto++; 354 m_freem(m); 355 return ENOBUFS; 356 } 357 358 /* Get IPsec-specific opaque pointer */ 359 if (esph == NULL || mtag != NULL) 360 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 361 M_XDATA, M_NOWAIT|M_ZERO); 362 else 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.esps_crypto++; 369 m_freem(m); 370 return ENOBUFS; 371 } 372 373 tc->tc_ptr = (caddr_t) mtag; 374 375 if (esph) { 376 struct cryptodesc *crda = crp->crp_desc; 377 378 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor")); 379 380 /* Authentication descriptor */ 381 crda->crd_skip = skip; 382 crda->crd_len = m->m_pkthdr.len - (skip + alen); 383 crda->crd_inject = m->m_pkthdr.len - alen; 384 385 crda->crd_alg = esph->type; 386 crda->crd_key = sav->key_auth->key_data; 387 crda->crd_klen = _KEYBITS(sav->key_auth); 388 389 /* Copy the authenticator */ 390 if (mtag == NULL) 391 m_copydata(m, m->m_pkthdr.len - alen, alen, 392 (caddr_t) (tc + 1)); 393 394 /* Chain authentication request */ 395 crde = crda->crd_next; 396 } else { 397 crde = crp->crp_desc; 398 } 399 400 /* Crypto operation descriptor */ 401 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 402 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 403 crp->crp_buf = (caddr_t) m; 404 crp->crp_callback = esp_input_cb; 405 crp->crp_sid = sav->tdb_cryptoid; 406 crp->crp_opaque = (caddr_t) tc; 407 408 /* These are passed as-is to the callback */ 409 tc->tc_spi = sav->spi; 410 tc->tc_dst = sav->sah->saidx.dst; 411 tc->tc_proto = sav->sah->saidx.proto; 412 tc->tc_protoff = protoff; 413 tc->tc_skip = skip; 414 415 /* Decryption descriptor */ 416 if (espx) { 417 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor")); 418 crde->crd_skip = skip + hlen; 419 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 420 crde->crd_inject = skip + hlen - sav->ivlen; 421 422 crde->crd_alg = espx->type; 423 crde->crd_key = sav->key_enc->key_data; 424 crde->crd_klen = _KEYBITS(sav->key_enc); 425 /* XXX Rounds ? */ 426 } 427 428 if (mtag == NULL) 429 return crypto_dispatch(crp); 430 else 431 return esp_input_cb(crp); 432 } 433 434 #ifdef INET6 435 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \ 436 if (saidx->dst.sa.sa_family == AF_INET6) { \ 437 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \ 438 } else { \ 439 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \ 440 } \ 441 } while (0) 442 #else 443 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \ 444 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag)) 445 #endif 446 447 /* 448 * ESP input callback from the crypto driver. 449 */ 450 static int 451 esp_input_cb(struct cryptop *crp) 452 { 453 u_int8_t lastthree[3], aalg[AH_HMAC_HASHLEN]; 454 int hlen, skip, protoff, error; 455 struct mbuf *m; 456 struct cryptodesc *crd; 457 struct auth_hash *esph; 458 struct enc_xform *espx; 459 struct tdb_crypto *tc; 460 struct m_tag *mtag; 461 struct secasvar *sav; 462 struct secasindex *saidx; 463 caddr_t ptr; 464 465 crd = crp->crp_desc; 466 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!")); 467 468 tc = (struct tdb_crypto *) crp->crp_opaque; 469 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!")); 470 skip = tc->tc_skip; 471 protoff = tc->tc_protoff; 472 mtag = (struct m_tag *) tc->tc_ptr; 473 m = (struct mbuf *) crp->crp_buf; 474 475 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 476 if (sav == NULL) { 477 espstat.esps_notdb++; 478 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 479 __func__, ipsec_address(&tc->tc_dst), 480 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 481 error = ENOBUFS; /*XXX*/ 482 goto bad; 483 } 484 485 saidx = &sav->sah->saidx; 486 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 487 saidx->dst.sa.sa_family == AF_INET6, 488 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 489 490 esph = sav->tdb_authalgxform; 491 espx = sav->tdb_encalgxform; 492 493 /* Check for crypto errors */ 494 if (crp->crp_etype) { 495 /* Reset the session ID */ 496 if (sav->tdb_cryptoid != 0) 497 sav->tdb_cryptoid = crp->crp_sid; 498 499 if (crp->crp_etype == EAGAIN) { 500 KEY_FREESAV(&sav); 501 error = crypto_dispatch(crp); 502 return error; 503 } 504 505 espstat.esps_noxform++; 506 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 507 error = crp->crp_etype; 508 goto bad; 509 } 510 511 /* Shouldn't happen... */ 512 if (m == NULL) { 513 espstat.esps_crypto++; 514 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 515 error = EINVAL; 516 goto bad; 517 } 518 espstat.esps_hist[sav->alg_enc]++; 519 520 /* If authentication was performed, check now. */ 521 if (esph != NULL) { 522 /* 523 * If we have a tag, it means an IPsec-aware NIC did 524 * the verification for us. Otherwise we need to 525 * check the authentication calculation. 526 */ 527 ahstat.ahs_hist[sav->alg_auth]++; 528 if (mtag == NULL) { 529 /* Copy the authenticator from the packet */ 530 m_copydata(m, m->m_pkthdr.len - AH_HMAC_HASHLEN, 531 AH_HMAC_HASHLEN, aalg); 532 533 ptr = (caddr_t) (tc + 1); 534 535 /* Verify authenticator */ 536 if (bcmp(ptr, aalg, AH_HMAC_HASHLEN) != 0) { 537 DPRINTF(("%s: " 538 "authentication hash mismatch for packet in SA %s/%08lx\n", 539 __func__, 540 ipsec_address(&saidx->dst), 541 (u_long) ntohl(sav->spi))); 542 espstat.esps_badauth++; 543 error = EACCES; 544 goto bad; 545 } 546 } 547 548 /* Remove trailing authenticator */ 549 m_adj(m, -AH_HMAC_HASHLEN); 550 } 551 552 /* Release the crypto descriptors */ 553 free(tc, M_XDATA), tc = NULL; 554 crypto_freereq(crp), crp = NULL; 555 556 /* 557 * Packet is now decrypted. 558 */ 559 m->m_flags |= M_DECRYPTED; 560 561 /* 562 * Update replay sequence number, if appropriate. 563 */ 564 if (sav->replay) { 565 u_int32_t seq; 566 567 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 568 sizeof (seq), (caddr_t) &seq); 569 if (ipsec_updatereplay(ntohl(seq), sav)) { 570 DPRINTF(("%s: packet replay check for %s\n", __func__, 571 ipsec_logsastr(sav))); 572 espstat.esps_replay++; 573 error = ENOBUFS; 574 goto bad; 575 } 576 } 577 578 /* Determine the ESP header length */ 579 if (sav->flags & SADB_X_EXT_OLD) 580 hlen = sizeof (struct esp) + sav->ivlen; 581 else 582 hlen = sizeof (struct newesp) + sav->ivlen; 583 584 /* Remove the ESP header and IV from the mbuf. */ 585 error = m_striphdr(m, skip, hlen); 586 if (error) { 587 espstat.esps_hdrops++; 588 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 589 ipsec_address(&sav->sah->saidx.dst), 590 (u_long) ntohl(sav->spi))); 591 goto bad; 592 } 593 594 /* Save the last three bytes of decrypted data */ 595 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 596 597 /* Verify pad length */ 598 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 599 espstat.esps_badilen++; 600 DPRINTF(("%s: invalid padding length %d for %u byte packet " 601 "in SA %s/%08lx\n", __func__, 602 lastthree[1], m->m_pkthdr.len - skip, 603 ipsec_address(&sav->sah->saidx.dst), 604 (u_long) ntohl(sav->spi))); 605 error = EINVAL; 606 goto bad; 607 } 608 609 /* Verify correct decryption by checking the last padding bytes */ 610 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 611 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 612 espstat.esps_badenc++; 613 DPRINTF(("%s: decryption failed for packet in " 614 "SA %s/%08lx\n", __func__, 615 ipsec_address(&sav->sah->saidx.dst), 616 (u_long) ntohl(sav->spi))); 617 error = EINVAL; 618 goto bad; 619 } 620 } 621 622 /* Trim the mbuf chain to remove trailing authenticator and padding */ 623 m_adj(m, -(lastthree[1] + 2)); 624 625 /* Restore the Next Protocol field */ 626 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 627 628 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag); 629 630 KEY_FREESAV(&sav); 631 return error; 632 bad: 633 if (sav) 634 KEY_FREESAV(&sav); 635 if (m != NULL) 636 m_freem(m); 637 if (tc != NULL) 638 free(tc, M_XDATA); 639 if (crp != NULL) 640 crypto_freereq(crp); 641 return error; 642 } 643 644 /* 645 * ESP output routine, called by ipsec[46]_process_packet(). 646 */ 647 static int 648 esp_output( 649 struct mbuf *m, 650 struct ipsecrequest *isr, 651 struct mbuf **mp, 652 int skip, 653 int protoff 654 ) 655 { 656 struct enc_xform *espx; 657 struct auth_hash *esph; 658 int hlen, rlen, plen, padding, blks, alen, i, roff; 659 struct mbuf *mo = (struct mbuf *) NULL; 660 struct tdb_crypto *tc; 661 struct secasvar *sav; 662 struct secasindex *saidx; 663 unsigned char *pad; 664 u_int8_t prot; 665 int error, maxpacketsize; 666 667 struct cryptodesc *crde = NULL, *crda = NULL; 668 struct cryptop *crp; 669 670 IPSEC_SPLASSERT_SOFTNET(__func__); 671 672 sav = isr->sav; 673 IPSEC_ASSERT(sav != NULL, ("null SA")); 674 esph = sav->tdb_authalgxform; 675 espx = sav->tdb_encalgxform; 676 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 677 678 if (sav->flags & SADB_X_EXT_OLD) 679 hlen = sizeof (struct esp) + sav->ivlen; 680 else 681 hlen = sizeof (struct newesp) + sav->ivlen; 682 683 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 684 /* 685 * NB: The null encoding transform has a blocksize of 4 686 * so that headers are properly aligned. 687 */ 688 blks = espx->blocksize; /* IV blocksize */ 689 690 /* XXX clamp padding length a la KAME??? */ 691 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 692 plen = rlen + padding; /* Padded payload length. */ 693 694 if (esph) 695 alen = AH_HMAC_HASHLEN; 696 else 697 alen = 0; 698 699 espstat.esps_output++; 700 701 saidx = &sav->sah->saidx; 702 /* Check for maximum packet size violations. */ 703 switch (saidx->dst.sa.sa_family) { 704 #ifdef INET 705 case AF_INET: 706 maxpacketsize = IP_MAXPACKET; 707 break; 708 #endif /* INET */ 709 #ifdef INET6 710 case AF_INET6: 711 maxpacketsize = IPV6_MAXPACKET; 712 break; 713 #endif /* INET6 */ 714 default: 715 DPRINTF(("%s: unknown/unsupported protocol " 716 "family %d, SA %s/%08lx\n", __func__, 717 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst), 718 (u_long) ntohl(sav->spi))); 719 espstat.esps_nopf++; 720 error = EPFNOSUPPORT; 721 goto bad; 722 } 723 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 724 DPRINTF(("%s: packet in SA %s/%08lx got too big " 725 "(len %u, max len %u)\n", __func__, 726 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi), 727 skip + hlen + rlen + padding + alen, maxpacketsize)); 728 espstat.esps_toobig++; 729 error = EMSGSIZE; 730 goto bad; 731 } 732 733 /* Update the counters. */ 734 espstat.esps_obytes += m->m_pkthdr.len - skip; 735 736 m = m_unshare(m, M_NOWAIT); 737 if (m == NULL) { 738 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 739 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 740 espstat.esps_hdrops++; 741 error = ENOBUFS; 742 goto bad; 743 } 744 745 /* Inject ESP header. */ 746 mo = m_makespace(m, skip, hlen, &roff); 747 if (mo == NULL) { 748 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 749 __func__, hlen, ipsec_address(&saidx->dst), 750 (u_long) ntohl(sav->spi))); 751 espstat.esps_hdrops++; /* XXX diffs from openbsd */ 752 error = ENOBUFS; 753 goto bad; 754 } 755 756 /* Initialize ESP header. */ 757 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t)); 758 if (sav->replay) { 759 u_int32_t replay; 760 761 #ifdef REGRESSION 762 /* Emulate replay attack when ipsec_replay is TRUE. */ 763 if (!ipsec_replay) 764 #endif 765 sav->replay->count++; 766 replay = htonl(sav->replay->count); 767 bcopy((caddr_t) &replay, 768 mtod(mo, caddr_t) + roff + sizeof(u_int32_t), 769 sizeof(u_int32_t)); 770 } 771 772 /* 773 * Add padding -- better to do it ourselves than use the crypto engine, 774 * although if/when we support compression, we'd have to do that. 775 */ 776 pad = (u_char *) m_pad(m, padding + alen); 777 if (pad == NULL) { 778 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 779 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 780 m = NULL; /* NB: free'd by m_pad */ 781 error = ENOBUFS; 782 goto bad; 783 } 784 785 /* 786 * Add padding: random, zero, or self-describing. 787 * XXX catch unexpected setting 788 */ 789 switch (sav->flags & SADB_X_EXT_PMASK) { 790 case SADB_X_EXT_PRAND: 791 (void) read_random(pad, padding - 2); 792 break; 793 case SADB_X_EXT_PZERO: 794 bzero(pad, padding - 2); 795 break; 796 case SADB_X_EXT_PSEQ: 797 for (i = 0; i < padding - 2; i++) 798 pad[i] = i+1; 799 break; 800 } 801 802 /* Fix padding length and Next Protocol in padding itself. */ 803 pad[padding - 2] = padding - 2; 804 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 805 806 /* Fix Next Protocol in IPv4/IPv6 header. */ 807 prot = IPPROTO_ESP; 808 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 809 810 /* Get crypto descriptors. */ 811 crp = crypto_getreq(esph && espx ? 2 : 1); 812 if (crp == NULL) { 813 DPRINTF(("%s: failed to acquire crypto descriptors\n", 814 __func__)); 815 espstat.esps_crypto++; 816 error = ENOBUFS; 817 goto bad; 818 } 819 820 if (espx) { 821 crde = crp->crp_desc; 822 crda = crde->crd_next; 823 824 /* Encryption descriptor. */ 825 crde->crd_skip = skip + hlen; 826 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 827 crde->crd_flags = CRD_F_ENCRYPT; 828 crde->crd_inject = skip + hlen - sav->ivlen; 829 830 /* Encryption operation. */ 831 crde->crd_alg = espx->type; 832 crde->crd_key = sav->key_enc->key_data; 833 crde->crd_klen = _KEYBITS(sav->key_enc); 834 /* XXX Rounds ? */ 835 } else 836 crda = crp->crp_desc; 837 838 /* IPsec-specific opaque crypto info. */ 839 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 840 M_XDATA, M_NOWAIT|M_ZERO); 841 if (tc == NULL) { 842 crypto_freereq(crp); 843 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 844 espstat.esps_crypto++; 845 error = ENOBUFS; 846 goto bad; 847 } 848 849 /* Callback parameters */ 850 tc->tc_isr = isr; 851 tc->tc_spi = sav->spi; 852 tc->tc_dst = saidx->dst; 853 tc->tc_proto = saidx->proto; 854 855 /* Crypto operation descriptor. */ 856 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 857 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 858 crp->crp_buf = (caddr_t) m; 859 crp->crp_callback = esp_output_cb; 860 crp->crp_opaque = (caddr_t) tc; 861 crp->crp_sid = sav->tdb_cryptoid; 862 863 if (esph) { 864 /* Authentication descriptor. */ 865 crda->crd_skip = skip; 866 crda->crd_len = m->m_pkthdr.len - (skip + alen); 867 crda->crd_inject = m->m_pkthdr.len - alen; 868 869 /* Authentication operation. */ 870 crda->crd_alg = esph->type; 871 crda->crd_key = sav->key_auth->key_data; 872 crda->crd_klen = _KEYBITS(sav->key_auth); 873 } 874 875 return crypto_dispatch(crp); 876 bad: 877 if (m) 878 m_freem(m); 879 return (error); 880 } 881 882 /* 883 * ESP output callback from the crypto driver. 884 */ 885 static int 886 esp_output_cb(struct cryptop *crp) 887 { 888 struct tdb_crypto *tc; 889 struct ipsecrequest *isr; 890 struct secasvar *sav; 891 struct mbuf *m; 892 int err, error; 893 894 tc = (struct tdb_crypto *) crp->crp_opaque; 895 IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); 896 m = (struct mbuf *) crp->crp_buf; 897 898 isr = tc->tc_isr; 899 IPSECREQUEST_LOCK(isr); 900 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 901 if (sav == NULL) { 902 espstat.esps_notdb++; 903 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 904 __func__, ipsec_address(&tc->tc_dst), 905 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 906 error = ENOBUFS; /*XXX*/ 907 goto bad; 908 } 909 IPSEC_ASSERT(isr->sav == sav, 910 ("SA changed was %p now %p\n", isr->sav, sav)); 911 912 /* Check for crypto errors. */ 913 if (crp->crp_etype) { 914 /* Reset session ID. */ 915 if (sav->tdb_cryptoid != 0) 916 sav->tdb_cryptoid = crp->crp_sid; 917 918 if (crp->crp_etype == EAGAIN) { 919 KEY_FREESAV(&sav); 920 IPSECREQUEST_UNLOCK(isr); 921 error = crypto_dispatch(crp); 922 return error; 923 } 924 925 espstat.esps_noxform++; 926 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 927 error = crp->crp_etype; 928 goto bad; 929 } 930 931 /* Shouldn't happen... */ 932 if (m == NULL) { 933 espstat.esps_crypto++; 934 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 935 error = EINVAL; 936 goto bad; 937 } 938 espstat.esps_hist[sav->alg_enc]++; 939 if (sav->tdb_authalgxform != NULL) 940 ahstat.ahs_hist[sav->alg_auth]++; 941 942 /* Release crypto descriptors. */ 943 free(tc, M_XDATA); 944 crypto_freereq(crp); 945 946 #ifdef REGRESSION 947 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 948 if (ipsec_integrity) { 949 static unsigned char ipseczeroes[AH_HMAC_HASHLEN]; 950 struct auth_hash *esph; 951 952 /* 953 * Corrupt HMAC if we want to test integrity verification of 954 * the other side. 955 */ 956 esph = sav->tdb_authalgxform; 957 if (esph != NULL) { 958 m_copyback(m, m->m_pkthdr.len - AH_HMAC_HASHLEN, 959 AH_HMAC_HASHLEN, ipseczeroes); 960 } 961 } 962 #endif 963 964 /* NB: m is reclaimed by ipsec_process_done. */ 965 err = ipsec_process_done(m, isr); 966 KEY_FREESAV(&sav); 967 IPSECREQUEST_UNLOCK(isr); 968 return err; 969 bad: 970 if (sav) 971 KEY_FREESAV(&sav); 972 IPSECREQUEST_UNLOCK(isr); 973 if (m) 974 m_freem(m); 975 free(tc, M_XDATA); 976 crypto_freereq(crp); 977 return error; 978 } 979 980 static struct xformsw esp_xformsw = { 981 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 982 esp_init, esp_zeroize, esp_input, 983 esp_output 984 }; 985 986 static void 987 esp_attach(void) 988 { 989 #define MAXIV(xform) \ 990 if (xform.blocksize > esp_max_ivlen) \ 991 esp_max_ivlen = xform.blocksize \ 992 993 esp_max_ivlen = 0; 994 MAXIV(enc_xform_des); /* SADB_EALG_DESCBC */ 995 MAXIV(enc_xform_3des); /* SADB_EALG_3DESCBC */ 996 MAXIV(enc_xform_rijndael128); /* SADB_X_EALG_AES */ 997 MAXIV(enc_xform_blf); /* SADB_X_EALG_BLOWFISHCBC */ 998 MAXIV(enc_xform_cast5); /* SADB_X_EALG_CAST128CBC */ 999 MAXIV(enc_xform_skipjack); /* SADB_X_EALG_SKIPJACK */ 1000 MAXIV(enc_xform_null); /* SADB_EALG_NULL */ 1001 MAXIV(enc_xform_camellia); /* SADB_X_EALG_CAMELLIACBC */ 1002 1003 xform_register(&esp_xformsw); 1004 #undef MAXIV 1005 } 1006 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL); 1007