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 } 117 return NULL; 118 } 119 120 size_t 121 esp_hdrsiz(struct secasvar *sav) 122 { 123 size_t size; 124 125 if (sav != NULL) { 126 /*XXX not right for null algorithm--does it matter??*/ 127 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 128 ("SA with null xform")); 129 if (sav->flags & SADB_X_EXT_OLD) 130 size = sizeof (struct esp); 131 else 132 size = sizeof (struct newesp); 133 size += sav->tdb_encalgxform->blocksize + 9; 134 /*XXX need alg check???*/ 135 if (sav->tdb_authalgxform != NULL && sav->replay) 136 size += ah_hdrsiz(sav); 137 } else { 138 /* 139 * base header size 140 * + max iv length for CBC mode 141 * + max pad length 142 * + sizeof (pad length field) 143 * + sizeof (next header field) 144 * + max icv supported. 145 */ 146 size = sizeof (struct newesp) + esp_max_ivlen + 9 + 16; 147 } 148 return size; 149 } 150 151 /* 152 * esp_init() is called when an SPI is being set up. 153 */ 154 static int 155 esp_init(struct secasvar *sav, struct xformsw *xsp) 156 { 157 struct enc_xform *txform; 158 struct cryptoini cria, crie; 159 int keylen; 160 int error; 161 162 txform = esp_algorithm_lookup(sav->alg_enc); 163 if (txform == NULL) { 164 DPRINTF(("%s: unsupported encryption algorithm %d\n", 165 __func__, sav->alg_enc)); 166 return EINVAL; 167 } 168 if (sav->key_enc == NULL) { 169 DPRINTF(("%s: no encoding key for %s algorithm\n", 170 __func__, txform->name)); 171 return EINVAL; 172 } 173 if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) { 174 DPRINTF(("%s: 4-byte IV not supported with protocol\n", 175 __func__)); 176 return EINVAL; 177 } 178 keylen = _KEYLEN(sav->key_enc); 179 if (txform->minkey > keylen || keylen > txform->maxkey) { 180 DPRINTF(("%s: invalid key length %u, must be in the range " 181 "[%u..%u] for algorithm %s\n", __func__, 182 keylen, txform->minkey, txform->maxkey, 183 txform->name)); 184 return EINVAL; 185 } 186 187 /* 188 * NB: The null xform needs a non-zero blocksize to keep the 189 * crypto code happy but if we use it to set ivlen then 190 * the ESP header will be processed incorrectly. The 191 * compromise is to force it to zero here. 192 */ 193 sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize); 194 sav->iv = (caddr_t) malloc(sav->ivlen, M_XDATA, M_WAITOK); 195 if (sav->iv == NULL) { 196 DPRINTF(("%s: no memory for IV\n", __func__)); 197 return EINVAL; 198 } 199 key_randomfill(sav->iv, sav->ivlen); /*XXX*/ 200 201 /* 202 * Setup AH-related state. 203 */ 204 if (sav->alg_auth != 0) { 205 error = ah_init0(sav, xsp, &cria); 206 if (error) 207 return error; 208 } 209 210 /* NB: override anything set in ah_init0 */ 211 sav->tdb_xform = xsp; 212 sav->tdb_encalgxform = txform; 213 214 /* Initialize crypto session. */ 215 bzero(&crie, sizeof (crie)); 216 crie.cri_alg = sav->tdb_encalgxform->type; 217 crie.cri_klen = _KEYBITS(sav->key_enc); 218 crie.cri_key = sav->key_enc->key_data; 219 /* XXX Rounds ? */ 220 221 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 222 /* init both auth & enc */ 223 crie.cri_next = &cria; 224 error = crypto_newsession(&sav->tdb_cryptoid, 225 &crie, crypto_support); 226 } else if (sav->tdb_encalgxform) { 227 error = crypto_newsession(&sav->tdb_cryptoid, 228 &crie, crypto_support); 229 } else if (sav->tdb_authalgxform) { 230 error = crypto_newsession(&sav->tdb_cryptoid, 231 &cria, crypto_support); 232 } else { 233 /* XXX cannot happen? */ 234 DPRINTF(("%s: no encoding OR authentication xform!\n", 235 __func__)); 236 error = EINVAL; 237 } 238 return error; 239 } 240 241 /* 242 * Paranoia. 243 */ 244 static int 245 esp_zeroize(struct secasvar *sav) 246 { 247 /* NB: ah_zerorize free's the crypto session state */ 248 int error = ah_zeroize(sav); 249 250 if (sav->key_enc) 251 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc)); 252 if (sav->iv) { 253 free(sav->iv, M_XDATA); 254 sav->iv = NULL; 255 } 256 sav->tdb_encalgxform = NULL; 257 sav->tdb_xform = NULL; 258 return error; 259 } 260 261 /* 262 * ESP input processing, called (eventually) through the protocol switch. 263 */ 264 static int 265 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 266 { 267 struct auth_hash *esph; 268 struct enc_xform *espx; 269 struct tdb_ident *tdbi; 270 struct tdb_crypto *tc; 271 int plen, alen, hlen; 272 struct m_tag *mtag; 273 struct newesp *esp; 274 275 struct cryptodesc *crde; 276 struct cryptop *crp; 277 278 IPSEC_SPLASSERT_SOFTNET(__func__); 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 NET_LOCK_GIANT(); 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 NET_UNLOCK_GIANT(); 503 return error; 504 } 505 506 espstat.esps_noxform++; 507 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 508 error = crp->crp_etype; 509 goto bad; 510 } 511 512 /* Shouldn't happen... */ 513 if (m == NULL) { 514 espstat.esps_crypto++; 515 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 516 error = EINVAL; 517 goto bad; 518 } 519 espstat.esps_hist[sav->alg_enc]++; 520 521 /* If authentication was performed, check now. */ 522 if (esph != NULL) { 523 /* 524 * If we have a tag, it means an IPsec-aware NIC did 525 * the verification for us. Otherwise we need to 526 * check the authentication calculation. 527 */ 528 ahstat.ahs_hist[sav->alg_auth]++; 529 if (mtag == NULL) { 530 /* Copy the authenticator from the packet */ 531 m_copydata(m, m->m_pkthdr.len - AH_HMAC_HASHLEN, 532 AH_HMAC_HASHLEN, aalg); 533 534 ptr = (caddr_t) (tc + 1); 535 536 /* Verify authenticator */ 537 if (bcmp(ptr, aalg, AH_HMAC_HASHLEN) != 0) { 538 DPRINTF(("%s: " 539 "authentication hash mismatch for packet in SA %s/%08lx\n", 540 __func__, 541 ipsec_address(&saidx->dst), 542 (u_long) ntohl(sav->spi))); 543 espstat.esps_badauth++; 544 error = EACCES; 545 goto bad; 546 } 547 } 548 549 /* Remove trailing authenticator */ 550 m_adj(m, -AH_HMAC_HASHLEN); 551 } 552 553 /* Release the crypto descriptors */ 554 free(tc, M_XDATA), tc = NULL; 555 crypto_freereq(crp), crp = NULL; 556 557 /* 558 * Packet is now decrypted. 559 */ 560 m->m_flags |= M_DECRYPTED; 561 562 /* 563 * Update replay sequence number, if appropriate. 564 */ 565 if (sav->replay) { 566 u_int32_t seq; 567 568 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 569 sizeof (seq), (caddr_t) &seq); 570 if (ipsec_updatereplay(ntohl(seq), sav)) { 571 DPRINTF(("%s: packet replay check for %s\n", __func__, 572 ipsec_logsastr(sav))); 573 espstat.esps_replay++; 574 error = ENOBUFS; 575 goto bad; 576 } 577 } 578 579 /* Determine the ESP header length */ 580 if (sav->flags & SADB_X_EXT_OLD) 581 hlen = sizeof (struct esp) + sav->ivlen; 582 else 583 hlen = sizeof (struct newesp) + sav->ivlen; 584 585 /* Remove the ESP header and IV from the mbuf. */ 586 error = m_striphdr(m, skip, hlen); 587 if (error) { 588 espstat.esps_hdrops++; 589 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 590 ipsec_address(&sav->sah->saidx.dst), 591 (u_long) ntohl(sav->spi))); 592 goto bad; 593 } 594 595 /* Save the last three bytes of decrypted data */ 596 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 597 598 /* Verify pad length */ 599 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 600 espstat.esps_badilen++; 601 DPRINTF(("%s: invalid padding length %d for %u byte packet " 602 "in SA %s/%08lx\n", __func__, 603 lastthree[1], m->m_pkthdr.len - skip, 604 ipsec_address(&sav->sah->saidx.dst), 605 (u_long) ntohl(sav->spi))); 606 error = EINVAL; 607 goto bad; 608 } 609 610 /* Verify correct decryption by checking the last padding bytes */ 611 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 612 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 613 espstat.esps_badenc++; 614 DPRINTF(("%s: decryption failed for packet in " 615 "SA %s/%08lx\n", __func__, 616 ipsec_address(&sav->sah->saidx.dst), 617 (u_long) ntohl(sav->spi))); 618 error = EINVAL; 619 goto bad; 620 } 621 } 622 623 /* Trim the mbuf chain to remove trailing authenticator and padding */ 624 m_adj(m, -(lastthree[1] + 2)); 625 626 /* Restore the Next Protocol field */ 627 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 628 629 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag); 630 631 KEY_FREESAV(&sav); 632 NET_UNLOCK_GIANT(); 633 return error; 634 bad: 635 if (sav) 636 KEY_FREESAV(&sav); 637 if (m != NULL) 638 m_freem(m); 639 if (tc != NULL) 640 free(tc, M_XDATA); 641 if (crp != NULL) 642 crypto_freereq(crp); 643 NET_UNLOCK_GIANT(); 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 struct enc_xform *espx; 660 struct auth_hash *esph; 661 int hlen, rlen, plen, padding, blks, alen, i, roff; 662 struct mbuf *mo = (struct mbuf *) NULL; 663 struct tdb_crypto *tc; 664 struct secasvar *sav; 665 struct secasindex *saidx; 666 unsigned char *pad; 667 u_int8_t prot; 668 int error, maxpacketsize; 669 670 struct cryptodesc *crde = NULL, *crda = NULL; 671 struct cryptop *crp; 672 673 IPSEC_SPLASSERT_SOFTNET(__func__); 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 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 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 espstat.esps_toobig++; 732 error = EMSGSIZE; 733 goto bad; 734 } 735 736 /* Update the counters. */ 737 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 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 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 (!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 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 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 struct tdb_crypto *tc; 892 struct ipsecrequest *isr; 893 struct secasvar *sav; 894 struct mbuf *m; 895 int err, error; 896 897 NET_LOCK_GIANT(); 898 899 tc = (struct tdb_crypto *) crp->crp_opaque; 900 IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); 901 m = (struct mbuf *) crp->crp_buf; 902 903 isr = tc->tc_isr; 904 IPSECREQUEST_LOCK(isr); 905 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 906 if (sav == NULL) { 907 espstat.esps_notdb++; 908 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 909 __func__, ipsec_address(&tc->tc_dst), 910 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 911 error = ENOBUFS; /*XXX*/ 912 goto bad; 913 } 914 IPSEC_ASSERT(isr->sav == sav, 915 ("SA changed was %p now %p\n", isr->sav, sav)); 916 917 /* Check for crypto errors. */ 918 if (crp->crp_etype) { 919 /* Reset session ID. */ 920 if (sav->tdb_cryptoid != 0) 921 sav->tdb_cryptoid = crp->crp_sid; 922 923 if (crp->crp_etype == EAGAIN) { 924 KEY_FREESAV(&sav); 925 IPSECREQUEST_UNLOCK(isr); 926 error = crypto_dispatch(crp); 927 NET_UNLOCK_GIANT(); 928 return error; 929 } 930 931 espstat.esps_noxform++; 932 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 933 error = crp->crp_etype; 934 goto bad; 935 } 936 937 /* Shouldn't happen... */ 938 if (m == NULL) { 939 espstat.esps_crypto++; 940 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 941 error = EINVAL; 942 goto bad; 943 } 944 espstat.esps_hist[sav->alg_enc]++; 945 if (sav->tdb_authalgxform != NULL) 946 ahstat.ahs_hist[sav->alg_auth]++; 947 948 /* Release crypto descriptors. */ 949 free(tc, M_XDATA); 950 crypto_freereq(crp); 951 952 #ifdef REGRESSION 953 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 954 if (ipsec_integrity) { 955 static unsigned char ipseczeroes[AH_HMAC_HASHLEN]; 956 struct auth_hash *esph; 957 958 /* 959 * Corrupt HMAC if we want to test integrity verification of 960 * the other side. 961 */ 962 esph = sav->tdb_authalgxform; 963 if (esph != NULL) { 964 m_copyback(m, m->m_pkthdr.len - AH_HMAC_HASHLEN, 965 AH_HMAC_HASHLEN, ipseczeroes); 966 } 967 } 968 #endif 969 970 /* NB: m is reclaimed by ipsec_process_done. */ 971 err = ipsec_process_done(m, isr); 972 KEY_FREESAV(&sav); 973 IPSECREQUEST_UNLOCK(isr); 974 NET_UNLOCK_GIANT(); 975 return err; 976 bad: 977 if (sav) 978 KEY_FREESAV(&sav); 979 IPSECREQUEST_UNLOCK(isr); 980 if (m) 981 m_freem(m); 982 free(tc, M_XDATA); 983 crypto_freereq(crp); 984 NET_UNLOCK_GIANT(); 985 return error; 986 } 987 988 static struct xformsw esp_xformsw = { 989 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 990 esp_init, esp_zeroize, esp_input, 991 esp_output 992 }; 993 994 static void 995 esp_attach(void) 996 { 997 #define MAXIV(xform) \ 998 if (xform.blocksize > esp_max_ivlen) \ 999 esp_max_ivlen = xform.blocksize \ 1000 1001 esp_max_ivlen = 0; 1002 MAXIV(enc_xform_des); /* SADB_EALG_DESCBC */ 1003 MAXIV(enc_xform_3des); /* SADB_EALG_3DESCBC */ 1004 MAXIV(enc_xform_rijndael128); /* SADB_X_EALG_AES */ 1005 MAXIV(enc_xform_blf); /* SADB_X_EALG_BLOWFISHCBC */ 1006 MAXIV(enc_xform_cast5); /* SADB_X_EALG_CAST128CBC */ 1007 MAXIV(enc_xform_skipjack); /* SADB_X_EALG_SKIPJACK */ 1008 MAXIV(enc_xform_null); /* SADB_EALG_NULL */ 1009 1010 xform_register(&esp_xformsw); 1011 #undef MAXIV 1012 } 1013 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL); 1014