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