1 /* $NetBSD: xform_esp.c,v 1.5 2004/03/17 00:21:43 jonathan Exp $ */ 2 /* $FreeBSD: src/sys/netipsec/xform_esp.c,v 1.2.2.1 2003/01/24 05:11:36 sam Exp $ */ 3 /* $OpenBSD: ip_esp.c,v 1.69 2001/06/26 06:18:59 angelos Exp $ */ 4 5 /* 6 * The authors of this code are John Ioannidis (ji@tla.org), 7 * Angelos D. Keromytis (kermit@csd.uch.gr) and 8 * Niels Provos (provos@physnet.uni-hamburg.de). 9 * 10 * The original version of this code was written by John Ioannidis 11 * for BSD/OS in Athens, Greece, in November 1995. 12 * 13 * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996, 14 * by Angelos D. Keromytis. 15 * 16 * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis 17 * and Niels Provos. 18 * 19 * Additional features in 1999 by Angelos D. Keromytis. 20 * 21 * Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis, 22 * Angelos D. Keromytis and Niels Provos. 23 * Copyright (c) 2001 Angelos D. Keromytis. 24 * 25 * Permission to use, copy, and modify this software with or without fee 26 * is hereby granted, provided that this entire notice is included in 27 * all copies of any software which is or includes a copy or 28 * modification of this software. 29 * You may use this code under the GNU public license if you so wish. Please 30 * contribute changes back to the authors under this freer than GPL license 31 * so that we may further the use of strong encryption without limitations to 32 * all. 33 * 34 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR 35 * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY 36 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE 37 * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR 38 * PURPOSE. 39 */ 40 41 #include <sys/cdefs.h> 42 __KERNEL_RCSID(0, "$NetBSD: xform_esp.c,v 1.5 2004/03/17 00:21:43 jonathan Exp $"); 43 44 #include "opt_inet.h" 45 #ifdef __FreeBSD__ 46 #include "opt_inet6.h" 47 #endif 48 49 #include <sys/param.h> 50 #include <sys/systm.h> 51 #include <sys/mbuf.h> 52 #include <sys/socket.h> 53 #include <sys/syslog.h> 54 #include <sys/kernel.h> 55 /*#include <sys/random.h>*/ 56 #include <sys/sysctl.h> 57 58 #include <net/if.h> 59 60 #include <netinet/in.h> 61 #include <netinet/in_systm.h> 62 #include <netinet/ip.h> 63 #include <netinet/ip_ecn.h> 64 #include <netinet/ip6.h> 65 66 #include <net/route.h> 67 #include <netipsec/ipsec.h> 68 #include <netipsec/ah.h> 69 #include <netipsec/ah_var.h> 70 #include <netipsec/esp.h> 71 #include <netipsec/esp_var.h> 72 #include <netipsec/xform.h> 73 74 #ifdef INET6 75 #include <netinet6/ip6_var.h> 76 #include <netipsec/ipsec6.h> 77 # ifdef __FreeBSD__ 78 # include <netinet6/ip6_ecn.h> 79 # endif 80 #endif 81 82 #include <netipsec/key.h> 83 #include <netipsec/key_debug.h> 84 85 #include <netipsec/ipsec_osdep.h> 86 87 #include <opencrypto/cryptodev.h> 88 #include <opencrypto/xform.h> 89 90 int esp_enable = 1; 91 struct espstat espstat; 92 93 #ifdef __FreeBSD__ 94 SYSCTL_DECL(_net_inet_esp); 95 SYSCTL_INT(_net_inet_esp, OID_AUTO, 96 esp_enable, CTLFLAG_RW, &esp_enable, 0, ""); 97 SYSCTL_STRUCT(_net_inet_esp, IPSECCTL_STATS, 98 stats, CTLFLAG_RD, &espstat, espstat, ""); 99 #endif /* __FreeBSD__ */ 100 101 static int esp_max_ivlen; /* max iv length over all algorithms */ 102 103 static int esp_input_cb(struct cryptop *op); 104 static int esp_output_cb(struct cryptop *crp); 105 106 /* 107 * NB: this is public for use by the PF_KEY support. 108 * NB: if you add support here; be sure to add code to esp_attach below! 109 */ 110 struct enc_xform * 111 esp_algorithm_lookup(int alg) 112 { 113 if (alg >= ESP_ALG_MAX) 114 return NULL; 115 switch (alg) { 116 case SADB_EALG_DESCBC: 117 return &enc_xform_des; 118 case SADB_EALG_3DESCBC: 119 return &enc_xform_3des; 120 case SADB_X_EALG_AES: 121 return &enc_xform_rijndael128; 122 case SADB_X_EALG_BLOWFISHCBC: 123 return &enc_xform_blf; 124 case SADB_X_EALG_CAST128CBC: 125 return &enc_xform_cast5; 126 case SADB_X_EALG_SKIPJACK: 127 return &enc_xform_skipjack; 128 case SADB_EALG_NULL: 129 return &enc_xform_null; 130 } 131 return NULL; 132 } 133 134 size_t 135 esp_hdrsiz(struct secasvar *sav) 136 { 137 size_t size; 138 139 if (sav != NULL) { 140 /*XXX not right for null algorithm--does it matter??*/ 141 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 142 ("esp_hdrsiz: SA with null xform")); 143 if (sav->flags & SADB_X_EXT_OLD) 144 size = sizeof (struct esp); 145 else 146 size = sizeof (struct newesp); 147 size += sav->tdb_encalgxform->blocksize + 9; 148 /*XXX need alg check???*/ 149 if (sav->tdb_authalgxform != NULL && sav->replay) 150 size += ah_hdrsiz(sav); 151 } else { 152 /* 153 * base header size 154 * + max iv length for CBC mode 155 * + max pad length 156 * + sizeof (pad length field) 157 * + sizeof (next header field) 158 * + max icv supported. 159 */ 160 size = sizeof (struct newesp) + esp_max_ivlen + 9 + 16; 161 } 162 return size; 163 } 164 165 /* 166 * esp_init() is called when an SPI is being set up. 167 */ 168 static int 169 esp_init(struct secasvar *sav, struct xformsw *xsp) 170 { 171 struct enc_xform *txform; 172 struct cryptoini cria, crie; 173 int keylen; 174 int error; 175 176 txform = esp_algorithm_lookup(sav->alg_enc); 177 if (txform == NULL) { 178 DPRINTF(("esp_init: unsupported encryption algorithm %d\n", 179 sav->alg_enc)); 180 return EINVAL; 181 } 182 if (sav->key_enc == NULL) { 183 DPRINTF(("esp_init: no encoding key for %s algorithm\n", 184 txform->name)); 185 return EINVAL; 186 } 187 if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) { 188 DPRINTF(("esp_init: 4-byte IV not supported with protocol\n")); 189 return EINVAL; 190 } 191 keylen = _KEYLEN(sav->key_enc); 192 if (txform->minkey > keylen || keylen > txform->maxkey) { 193 DPRINTF(("esp_init: invalid key length %u, must be in " 194 "the range [%u..%u] for algorithm %s\n", 195 keylen, txform->minkey, txform->maxkey, 196 txform->name)); 197 return EINVAL; 198 } 199 200 /* 201 * NB: The null xform needs a non-zero blocksize to keep the 202 * crypto code happy but if we use it to set ivlen then 203 * the ESP header will be processed incorrectly. The 204 * compromise is to force it to zero here. 205 */ 206 sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize); 207 sav->iv = (caddr_t) malloc(sav->ivlen, M_XDATA, M_WAITOK); 208 if (sav->iv == NULL) { 209 DPRINTF(("esp_init: no memory for IV\n")); 210 return EINVAL; 211 } 212 key_randomfill(sav->iv, sav->ivlen); /*XXX*/ 213 214 /* 215 * Setup AH-related state. 216 */ 217 if (sav->alg_auth != 0) { 218 error = ah_init0(sav, xsp, &cria); 219 if (error) 220 return error; 221 } 222 223 /* NB: override anything set in ah_init0 */ 224 sav->tdb_xform = xsp; 225 sav->tdb_encalgxform = txform; 226 227 /* Initialize crypto session. */ 228 bzero(&crie, sizeof (crie)); 229 crie.cri_alg = sav->tdb_encalgxform->type; 230 crie.cri_klen = _KEYBITS(sav->key_enc); 231 crie.cri_key = _KEYBUF(sav->key_enc); 232 /* XXX Rounds ? */ 233 234 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 235 /* init both auth & enc */ 236 crie.cri_next = &cria; 237 error = crypto_newsession(&sav->tdb_cryptoid, 238 &crie, crypto_support); 239 } else if (sav->tdb_encalgxform) { 240 error = crypto_newsession(&sav->tdb_cryptoid, 241 &crie, crypto_support); 242 } else if (sav->tdb_authalgxform) { 243 error = crypto_newsession(&sav->tdb_cryptoid, 244 &cria, crypto_support); 245 } else { 246 /* XXX cannot happen? */ 247 DPRINTF(("esp_init: no encoding OR authentication xform!\n")); 248 error = EINVAL; 249 } 250 return error; 251 } 252 253 /* 254 * Paranoia. 255 */ 256 static int 257 esp_zeroize(struct secasvar *sav) 258 { 259 /* NB: ah_zerorize free's the crypto session state */ 260 int error = ah_zeroize(sav); 261 262 if (sav->key_enc) 263 bzero(_KEYBUF(sav->key_enc), _KEYLEN(sav->key_enc)); 264 /* NB: sav->iv is freed elsewhere, even though we malloc it! */ 265 sav->tdb_encalgxform = NULL; 266 sav->tdb_xform = NULL; 267 return error; 268 } 269 270 /* 271 * ESP input processing, called (eventually) through the protocol switch. 272 */ 273 static int 274 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 275 { 276 struct auth_hash *esph; 277 struct enc_xform *espx; 278 struct tdb_ident *tdbi; 279 struct tdb_crypto *tc; 280 int plen, alen, hlen; 281 struct m_tag *mtag; 282 struct newesp *esp; 283 284 struct cryptodesc *crde; 285 struct cryptop *crp; 286 287 IPSEC_SPLASSERT_SOFTNET("esp_input"); 288 289 IPSEC_ASSERT(sav != NULL, ("esp_input: null SA")); 290 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 291 ("esp_input: null encoding xform")); 292 IPSEC_ASSERT((skip&3) == 0 && (m->m_pkthdr.len&3) == 0, 293 ("esp_input: misaligned packet, skip %u pkt len %u", 294 skip, m->m_pkthdr.len)); 295 296 /* XXX don't pullup, just copy header */ 297 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 298 299 esph = sav->tdb_authalgxform; 300 espx = sav->tdb_encalgxform; 301 302 /* Determine the ESP header length */ 303 if (sav->flags & SADB_X_EXT_OLD) 304 hlen = sizeof (struct esp) + sav->ivlen; 305 else 306 hlen = sizeof (struct newesp) + sav->ivlen; 307 /* Authenticator hash size */ 308 alen = esph ? AH_HMAC_HASHLEN : 0; 309 310 /* 311 * Verify payload length is multiple of encryption algorithm 312 * block size. 313 * 314 * NB: This works for the null algorithm because the blocksize 315 * is 4 and all packets must be 4-byte aligned regardless 316 * of the algorithm. 317 */ 318 plen = m->m_pkthdr.len - (skip + hlen + alen); 319 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 320 DPRINTF(("esp_input: " 321 "payload of %d octets not a multiple of %d octets," 322 " SA %s/%08lx\n", 323 plen, espx->blocksize, 324 ipsec_address(&sav->sah->saidx.dst), 325 (u_long) ntohl(sav->spi))); 326 espstat.esps_badilen++; 327 m_freem(m); 328 return EINVAL; 329 } 330 331 /* 332 * Check sequence number. 333 */ 334 if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) { 335 DPRINTF(("esp_input: packet replay check for %s\n", 336 ipsec_logsastr(sav))); /*XXX*/ 337 espstat.esps_replay++; 338 m_freem(m); 339 return ENOBUFS; /*XXX*/ 340 } 341 342 /* Update the counters */ 343 espstat.esps_ibytes += m->m_pkthdr.len - skip - hlen - alen; 344 345 /* Find out if we've already done crypto */ 346 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL); 347 mtag != NULL; 348 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) { 349 tdbi = (struct tdb_ident *) (mtag + 1); 350 if (tdbi->proto == sav->sah->saidx.proto && 351 tdbi->spi == sav->spi && 352 !bcmp(&tdbi->dst, &sav->sah->saidx.dst, 353 sizeof(union sockaddr_union))) 354 break; 355 } 356 357 /* Get crypto descriptors */ 358 crp = crypto_getreq(esph && espx ? 2 : 1); 359 if (crp == NULL) { 360 DPRINTF(("esp_input: failed to acquire crypto descriptors\n")); 361 espstat.esps_crypto++; 362 m_freem(m); 363 return ENOBUFS; 364 } 365 366 /* Get IPsec-specific opaque pointer */ 367 if (esph == NULL || mtag != NULL) 368 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 369 M_XDATA, M_NOWAIT|M_ZERO); 370 else 371 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen, 372 M_XDATA, M_NOWAIT|M_ZERO); 373 if (tc == NULL) { 374 crypto_freereq(crp); 375 DPRINTF(("esp_input: failed to allocate tdb_crypto\n")); 376 espstat.esps_crypto++; 377 m_freem(m); 378 return ENOBUFS; 379 } 380 381 tc->tc_ptr = (caddr_t) mtag; 382 383 if (esph) { 384 struct cryptodesc *crda = crp->crp_desc; 385 386 IPSEC_ASSERT(crda != NULL, ("esp_input: null ah crypto descriptor")); 387 388 /* Authentication descriptor */ 389 crda->crd_skip = skip; 390 crda->crd_len = m->m_pkthdr.len - (skip + alen); 391 crda->crd_inject = m->m_pkthdr.len - alen; 392 393 crda->crd_alg = esph->type; 394 crda->crd_key = _KEYBUF(sav->key_auth); 395 crda->crd_klen = _KEYBITS(sav->key_auth); 396 397 /* Copy the authenticator */ 398 if (mtag == NULL) 399 m_copydata(m, m->m_pkthdr.len - alen, alen, 400 (caddr_t) (tc + 1)); 401 402 /* Chain authentication request */ 403 crde = crda->crd_next; 404 } else { 405 crde = crp->crp_desc; 406 } 407 408 /* Crypto operation descriptor */ 409 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 410 crp->crp_flags = CRYPTO_F_IMBUF; 411 crp->crp_buf = (caddr_t) m; 412 crp->crp_callback = esp_input_cb; 413 crp->crp_sid = sav->tdb_cryptoid; 414 crp->crp_opaque = (caddr_t) tc; 415 416 /* These are passed as-is to the callback */ 417 tc->tc_spi = sav->spi; 418 tc->tc_dst = sav->sah->saidx.dst; 419 tc->tc_proto = sav->sah->saidx.proto; 420 tc->tc_protoff = protoff; 421 tc->tc_skip = skip; 422 423 /* Decryption descriptor */ 424 if (espx) { 425 IPSEC_ASSERT(crde != NULL, ("esp_input: null esp crypto descriptor")); 426 crde->crd_skip = skip + hlen; 427 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 428 crde->crd_inject = skip + hlen - sav->ivlen; 429 430 crde->crd_alg = espx->type; 431 crde->crd_key = _KEYBUF(sav->key_enc); 432 crde->crd_klen = _KEYBITS(sav->key_enc); 433 /* XXX Rounds ? */ 434 } 435 436 if (mtag == NULL) 437 return crypto_dispatch(crp); 438 else 439 return esp_input_cb(crp); 440 } 441 442 #ifdef INET6 443 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \ 444 if (saidx->dst.sa.sa_family == AF_INET6) { \ 445 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \ 446 } else { \ 447 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \ 448 } \ 449 } while (0) 450 #else 451 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \ 452 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag)) 453 #endif 454 455 /* 456 * ESP input callback from the crypto driver. 457 */ 458 static int 459 esp_input_cb(struct cryptop *crp) 460 { 461 u_int8_t lastthree[3], aalg[AH_HMAC_HASHLEN]; 462 int s, hlen, skip, protoff, error; 463 struct mbuf *m; 464 struct cryptodesc *crd; 465 struct auth_hash *esph; 466 struct enc_xform *espx; 467 struct tdb_crypto *tc; 468 struct m_tag *mtag; 469 struct secasvar *sav; 470 struct secasindex *saidx; 471 caddr_t ptr; 472 473 crd = crp->crp_desc; 474 IPSEC_ASSERT(crd != NULL, ("esp_input_cb: null crypto descriptor!")); 475 476 tc = (struct tdb_crypto *) crp->crp_opaque; 477 IPSEC_ASSERT(tc != NULL, ("esp_input_cb: null opaque crypto data area!")); 478 skip = tc->tc_skip; 479 protoff = tc->tc_protoff; 480 mtag = (struct m_tag *) tc->tc_ptr; 481 m = (struct mbuf *) crp->crp_buf; 482 483 s = splsoftnet(); 484 485 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 486 if (sav == NULL) { 487 espstat.esps_notdb++; 488 DPRINTF(("esp_input_cb: SA expired while in crypto " 489 "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst), 490 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 491 error = ENOBUFS; /*XXX*/ 492 goto bad; 493 } 494 495 saidx = &sav->sah->saidx; 496 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 497 saidx->dst.sa.sa_family == AF_INET6, 498 ("ah_input_cb: unexpected protocol family %u", 499 saidx->dst.sa.sa_family)); 500 501 esph = sav->tdb_authalgxform; 502 espx = sav->tdb_encalgxform; 503 504 /* Check for crypto errors */ 505 if (crp->crp_etype) { 506 /* Reset the session ID */ 507 if (sav->tdb_cryptoid != 0) 508 sav->tdb_cryptoid = crp->crp_sid; 509 510 if (crp->crp_etype == EAGAIN) { 511 KEY_FREESAV(&sav); 512 splx(s); 513 return crypto_dispatch(crp); 514 } 515 516 espstat.esps_noxform++; 517 DPRINTF(("esp_input_cb: crypto error %d\n", crp->crp_etype)); 518 error = crp->crp_etype; 519 goto bad; 520 } 521 522 /* Shouldn't happen... */ 523 if (m == NULL) { 524 espstat.esps_crypto++; 525 DPRINTF(("esp_input_cb: bogus returned buffer from crypto\n")); 526 error = EINVAL; 527 goto bad; 528 } 529 espstat.esps_hist[sav->alg_enc]++; 530 531 /* If authentication was performed, check now. */ 532 if (esph != NULL) { 533 /* 534 * If we have a tag, it means an IPsec-aware NIC did 535 * the verification for us. Otherwise we need to 536 * check the authentication calculation. 537 */ 538 ahstat.ahs_hist[sav->alg_auth]++; 539 if (mtag == NULL) { 540 /* Copy the authenticator from the packet */ 541 m_copydata(m, m->m_pkthdr.len - esph->authsize, 542 esph->authsize, aalg); 543 544 ptr = (caddr_t) (tc + 1); 545 546 /* Verify authenticator */ 547 if (bcmp(ptr, aalg, esph->authsize) != 0) { 548 DPRINTF(("esp_input_cb: " 549 "authentication hash mismatch for packet in SA %s/%08lx\n", 550 ipsec_address(&saidx->dst), 551 (u_long) ntohl(sav->spi))); 552 espstat.esps_badauth++; 553 error = EACCES; 554 goto bad; 555 } 556 } 557 558 /* Remove trailing authenticator */ 559 m_adj(m, -(esph->authsize)); 560 } 561 562 /* Release the crypto descriptors */ 563 free(tc, M_XDATA), tc = NULL; 564 crypto_freereq(crp), crp = NULL; 565 566 /* 567 * Packet is now decrypted. 568 */ 569 m->m_flags |= M_DECRYPTED; 570 571 /* Determine the ESP header length */ 572 if (sav->flags & SADB_X_EXT_OLD) 573 hlen = sizeof (struct esp) + sav->ivlen; 574 else 575 hlen = sizeof (struct newesp) + sav->ivlen; 576 577 /* Remove the ESP header and IV from the mbuf. */ 578 error = m_striphdr(m, skip, hlen); 579 if (error) { 580 espstat.esps_hdrops++; 581 DPRINTF(("esp_input_cb: bad mbuf chain, SA %s/%08lx\n", 582 ipsec_address(&sav->sah->saidx.dst), 583 (u_long) ntohl(sav->spi))); 584 goto bad; 585 } 586 587 /* Save the last three bytes of decrypted data */ 588 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 589 590 /* Verify pad length */ 591 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 592 espstat.esps_badilen++; 593 DPRINTF(("esp_input_cb: invalid padding length %d " 594 "for %u byte packet in SA %s/%08lx\n", 595 lastthree[1], m->m_pkthdr.len - skip, 596 ipsec_address(&sav->sah->saidx.dst), 597 (u_long) ntohl(sav->spi))); 598 error = EINVAL; 599 goto bad; 600 } 601 602 /* Verify correct decryption by checking the last padding bytes */ 603 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 604 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 605 espstat.esps_badenc++; 606 DPRINTF(("esp_input_cb: decryption failed " 607 "for packet in SA %s/%08lx\n", 608 ipsec_address(&sav->sah->saidx.dst), 609 (u_long) ntohl(sav->spi))); 610 DPRINTF(("esp_input_cb: %x %x\n", lastthree[0], lastthree[1])); 611 error = EINVAL; 612 goto bad; 613 } 614 } 615 616 /* Trim the mbuf chain to remove trailing authenticator and padding */ 617 m_adj(m, -(lastthree[1] + 2)); 618 619 /* Restore the Next Protocol field */ 620 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 621 622 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag); 623 624 KEY_FREESAV(&sav); 625 splx(s); 626 return error; 627 bad: 628 if (sav) 629 KEY_FREESAV(&sav); 630 splx(s); 631 if (m != NULL) 632 m_freem(m); 633 if (tc != NULL) 634 free(tc, M_XDATA); 635 if (crp != NULL) 636 crypto_freereq(crp); 637 return error; 638 } 639 640 /* 641 * ESP output routine, called by ipsec[46]_process_packet(). 642 */ 643 static int 644 esp_output( 645 struct mbuf *m, 646 struct ipsecrequest *isr, 647 struct mbuf **mp, 648 int skip, 649 int protoff 650 ) 651 { 652 struct enc_xform *espx; 653 struct auth_hash *esph; 654 int hlen, rlen, plen, padding, blks, alen, i, roff; 655 struct mbuf *mo = (struct mbuf *) NULL; 656 struct tdb_crypto *tc; 657 struct secasvar *sav; 658 struct secasindex *saidx; 659 unsigned char *pad; 660 u_int8_t prot; 661 int error, maxpacketsize; 662 663 struct cryptodesc *crde = NULL, *crda = NULL; 664 struct cryptop *crp; 665 666 IPSEC_SPLASSERT_SOFTNET("esp_output"); 667 668 sav = isr->sav; 669 IPSEC_ASSERT(sav != NULL, ("esp_output: null SA")); 670 esph = sav->tdb_authalgxform; 671 espx = sav->tdb_encalgxform; 672 IPSEC_ASSERT(espx != NULL, ("esp_output: 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(("esp_output: unknown/unsupported protocol " 712 "family %d, SA %s/%08lx\n", 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(("esp_output: packet in SA %s/%08lx got too big " 721 "(len %u, max len %u)\n", 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_clone(m); 733 if (m == NULL) { 734 DPRINTF(("esp_output: cannot clone mbuf chain, SA %s/%08lx\n", 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(("esp_output: failed to inject %u byte ESP hdr for SA " 745 "%s/%08lx\n", 746 hlen, ipsec_address(&saidx->dst), 747 (u_long) ntohl(sav->spi))); 748 espstat.esps_hdrops++; /* XXX diffs from openbsd */ 749 error = ENOBUFS; 750 goto bad; 751 } 752 753 /* Initialize ESP header. */ 754 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t)); 755 if (sav->replay) { 756 u_int32_t replay = htonl(++(sav->replay->count)); 757 bcopy((caddr_t) &replay, 758 mtod(mo, caddr_t) + roff + sizeof(u_int32_t), 759 sizeof(u_int32_t)); 760 } 761 762 /* 763 * Add padding -- better to do it ourselves than use the crypto engine, 764 * although if/when we support compression, we'd have to do that. 765 */ 766 pad = (u_char *) m_pad(m, padding + alen); 767 if (pad == NULL) { 768 DPRINTF(("esp_output: m_pad failed for SA %s/%08lx\n", 769 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 770 m = NULL; /* NB: free'd by m_pad */ 771 error = ENOBUFS; 772 goto bad; 773 } 774 775 /* 776 * Add padding: random, zero, or self-describing. 777 * XXX catch unexpected setting 778 */ 779 switch (sav->flags & SADB_X_EXT_PMASK) { 780 case SADB_X_EXT_PRAND: 781 (void) read_random(pad, padding - 2); 782 break; 783 case SADB_X_EXT_PZERO: 784 bzero(pad, padding - 2); 785 break; 786 case SADB_X_EXT_PSEQ: 787 for (i = 0; i < padding - 2; i++) 788 pad[i] = i+1; 789 break; 790 } 791 792 /* Fix padding length and Next Protocol in padding itself. */ 793 pad[padding - 2] = padding - 2; 794 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 795 796 /* Fix Next Protocol in IPv4/IPv6 header. */ 797 prot = IPPROTO_ESP; 798 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 799 800 /* Get crypto descriptors. */ 801 crp = crypto_getreq(esph && espx ? 2 : 1); 802 if (crp == NULL) { 803 DPRINTF(("esp_output: failed to acquire crypto descriptors\n")); 804 espstat.esps_crypto++; 805 error = ENOBUFS; 806 goto bad; 807 } 808 809 if (espx) { 810 crde = crp->crp_desc; 811 crda = crde->crd_next; 812 813 /* Encryption descriptor. */ 814 crde->crd_skip = skip + hlen; 815 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 816 crde->crd_flags = CRD_F_ENCRYPT; 817 crde->crd_inject = skip + hlen - sav->ivlen; 818 819 /* Encryption operation. */ 820 crde->crd_alg = espx->type; 821 crde->crd_key = _KEYBUF(sav->key_enc); 822 crde->crd_klen = _KEYBITS(sav->key_enc); 823 /* XXX Rounds ? */ 824 } else 825 crda = crp->crp_desc; 826 827 /* IPsec-specific opaque crypto info. */ 828 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 829 M_XDATA, M_NOWAIT|M_ZERO); 830 if (tc == NULL) { 831 crypto_freereq(crp); 832 DPRINTF(("esp_output: failed to allocate tdb_crypto\n")); 833 espstat.esps_crypto++; 834 error = ENOBUFS; 835 goto bad; 836 } 837 838 /* Callback parameters */ 839 tc->tc_isr = isr; 840 tc->tc_spi = sav->spi; 841 tc->tc_dst = saidx->dst; 842 tc->tc_proto = saidx->proto; 843 844 /* Crypto operation descriptor. */ 845 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 846 crp->crp_flags = CRYPTO_F_IMBUF; 847 crp->crp_buf = (caddr_t) m; 848 crp->crp_callback = esp_output_cb; 849 crp->crp_opaque = (caddr_t) tc; 850 crp->crp_sid = sav->tdb_cryptoid; 851 852 if (esph) { 853 /* Authentication descriptor. */ 854 crda->crd_skip = skip; 855 crda->crd_len = m->m_pkthdr.len - (skip + alen); 856 crda->crd_inject = m->m_pkthdr.len - alen; 857 858 /* Authentication operation. */ 859 crda->crd_alg = esph->type; 860 crda->crd_key = _KEYBUF(sav->key_auth); 861 crda->crd_klen = _KEYBITS(sav->key_auth); 862 } 863 864 return crypto_dispatch(crp); 865 bad: 866 if (m) 867 m_freem(m); 868 return (error); 869 } 870 871 /* 872 * ESP output callback from the crypto driver. 873 */ 874 static int 875 esp_output_cb(struct cryptop *crp) 876 { 877 struct tdb_crypto *tc; 878 struct ipsecrequest *isr; 879 struct secasvar *sav; 880 struct mbuf *m; 881 int s, err, error; 882 883 tc = (struct tdb_crypto *) crp->crp_opaque; 884 IPSEC_ASSERT(tc != NULL, ("esp_output_cb: null opaque data area!")); 885 m = (struct mbuf *) crp->crp_buf; 886 887 s = splsoftnet(); 888 889 isr = tc->tc_isr; 890 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 891 if (sav == NULL) { 892 espstat.esps_notdb++; 893 DPRINTF(("esp_output_cb: SA expired while in crypto " 894 "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst), 895 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 896 error = ENOBUFS; /*XXX*/ 897 goto bad; 898 } 899 IPSEC_ASSERT(isr->sav == sav, 900 ("esp_output_cb: SA changed was %p now %p\n", isr->sav, sav)); 901 902 /* Check for crypto errors. */ 903 if (crp->crp_etype) { 904 /* Reset session ID. */ 905 if (sav->tdb_cryptoid != 0) 906 sav->tdb_cryptoid = crp->crp_sid; 907 908 if (crp->crp_etype == EAGAIN) { 909 KEY_FREESAV(&sav); 910 splx(s); 911 return crypto_dispatch(crp); 912 } 913 914 espstat.esps_noxform++; 915 DPRINTF(("esp_output_cb: crypto error %d\n", crp->crp_etype)); 916 error = crp->crp_etype; 917 goto bad; 918 } 919 920 /* Shouldn't happen... */ 921 if (m == NULL) { 922 espstat.esps_crypto++; 923 DPRINTF(("esp_output_cb: bogus returned buffer from crypto\n")); 924 error = EINVAL; 925 goto bad; 926 } 927 espstat.esps_hist[sav->alg_enc]++; 928 if (sav->tdb_authalgxform != NULL) 929 ahstat.ahs_hist[sav->alg_auth]++; 930 931 /* Release crypto descriptors. */ 932 free(tc, M_XDATA); 933 crypto_freereq(crp); 934 935 /* NB: m is reclaimed by ipsec_process_done. */ 936 err = ipsec_process_done(m, isr); 937 KEY_FREESAV(&sav); 938 splx(s); 939 return err; 940 bad: 941 if (sav) 942 KEY_FREESAV(&sav); 943 splx(s); 944 if (m) 945 m_freem(m); 946 free(tc, M_XDATA); 947 crypto_freereq(crp); 948 return error; 949 } 950 951 static struct xformsw esp_xformsw = { 952 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 953 esp_init, esp_zeroize, esp_input, 954 esp_output 955 }; 956 957 INITFN void 958 esp_attach(void) 959 { 960 #define MAXIV(xform) \ 961 if (xform.blocksize > esp_max_ivlen) \ 962 esp_max_ivlen = xform.blocksize \ 963 964 esp_max_ivlen = 0; 965 MAXIV(enc_xform_des); /* SADB_EALG_DESCBC */ 966 MAXIV(enc_xform_3des); /* SADB_EALG_3DESCBC */ 967 MAXIV(enc_xform_rijndael128); /* SADB_X_EALG_AES */ 968 MAXIV(enc_xform_blf); /* SADB_X_EALG_BLOWFISHCBC */ 969 MAXIV(enc_xform_cast5); /* SADB_X_EALG_CAST128CBC */ 970 MAXIV(enc_xform_skipjack); /* SADB_X_EALG_SKIPJACK */ 971 MAXIV(enc_xform_null); /* SADB_EALG_NULL */ 972 973 xform_register(&esp_xformsw); 974 #undef MAXIV 975 } 976 #ifdef __FreeBSD__ 977 SYSINIT(esp_xform_init, SI_SUB_DRIVERS, SI_ORDER_FIRST, esp_attach, NULL) 978 #else 979 #endif 980