1 /* $NetBSD: xform_esp.c,v 1.4 2003/10/06 22:05:15 tls 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 1.4 2003/10/06 22:05:15 tls 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 #include <netinet6/ip6_ecn.h> 78 #endif 79 80 #include <netipsec/key.h> 81 #include <netipsec/key_debug.h> 82 83 #include <netipsec/ipsec_osdep.h> 84 85 #include <opencrypto/cryptodev.h> 86 #include <opencrypto/xform.h> 87 88 int esp_enable = 1; 89 struct espstat espstat; 90 91 #ifdef __FreeBSD__ 92 SYSCTL_DECL(_net_inet_esp); 93 SYSCTL_INT(_net_inet_esp, OID_AUTO, 94 esp_enable, CTLFLAG_RW, &esp_enable, 0, ""); 95 SYSCTL_STRUCT(_net_inet_esp, IPSECCTL_STATS, 96 stats, CTLFLAG_RD, &espstat, espstat, ""); 97 #endif /* __FreeBSD__ */ 98 99 static int esp_max_ivlen; /* max iv length over all algorithms */ 100 101 static int esp_input_cb(struct cryptop *op); 102 static int esp_output_cb(struct cryptop *crp); 103 104 /* 105 * NB: this is public for use by the PF_KEY support. 106 * NB: if you add support here; be sure to add code to esp_attach below! 107 */ 108 struct enc_xform * 109 esp_algorithm_lookup(int alg) 110 { 111 if (alg >= ESP_ALG_MAX) 112 return NULL; 113 switch (alg) { 114 case SADB_EALG_DESCBC: 115 return &enc_xform_des; 116 case SADB_EALG_3DESCBC: 117 return &enc_xform_3des; 118 case SADB_X_EALG_AES: 119 return &enc_xform_rijndael128; 120 case SADB_X_EALG_BLOWFISHCBC: 121 return &enc_xform_blf; 122 case SADB_X_EALG_CAST128CBC: 123 return &enc_xform_cast5; 124 case SADB_X_EALG_SKIPJACK: 125 return &enc_xform_skipjack; 126 case SADB_EALG_NULL: 127 return &enc_xform_null; 128 } 129 return NULL; 130 } 131 132 size_t 133 esp_hdrsiz(struct secasvar *sav) 134 { 135 size_t size; 136 137 if (sav != NULL) { 138 /*XXX not right for null algorithm--does it matter??*/ 139 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 140 ("esp_hdrsiz: SA with null xform")); 141 if (sav->flags & SADB_X_EXT_OLD) 142 size = sizeof (struct esp); 143 else 144 size = sizeof (struct newesp); 145 size += sav->tdb_encalgxform->blocksize + 9; 146 /*XXX need alg check???*/ 147 if (sav->tdb_authalgxform != NULL && sav->replay) 148 size += ah_hdrsiz(sav); 149 } else { 150 /* 151 * base header size 152 * + max iv length for CBC mode 153 * + max pad length 154 * + sizeof (pad length field) 155 * + sizeof (next header field) 156 * + max icv supported. 157 */ 158 size = sizeof (struct newesp) + esp_max_ivlen + 9 + 16; 159 } 160 return size; 161 } 162 163 /* 164 * esp_init() is called when an SPI is being set up. 165 */ 166 static int 167 esp_init(struct secasvar *sav, struct xformsw *xsp) 168 { 169 struct enc_xform *txform; 170 struct cryptoini cria, crie; 171 int keylen; 172 int error; 173 174 txform = esp_algorithm_lookup(sav->alg_enc); 175 if (txform == NULL) { 176 DPRINTF(("esp_init: unsupported encryption algorithm %d\n", 177 sav->alg_enc)); 178 return EINVAL; 179 } 180 if (sav->key_enc == NULL) { 181 DPRINTF(("esp_init: no encoding key for %s algorithm\n", 182 txform->name)); 183 return EINVAL; 184 } 185 if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) { 186 DPRINTF(("esp_init: 4-byte IV not supported with protocol\n")); 187 return EINVAL; 188 } 189 keylen = _KEYLEN(sav->key_enc); 190 if (txform->minkey > keylen || keylen > txform->maxkey) { 191 DPRINTF(("esp_init: invalid key length %u, must be in " 192 "the range [%u..%u] for algorithm %s\n", 193 keylen, txform->minkey, txform->maxkey, 194 txform->name)); 195 return EINVAL; 196 } 197 198 /* 199 * NB: The null xform needs a non-zero blocksize to keep the 200 * crypto code happy but if we use it to set ivlen then 201 * the ESP header will be processed incorrectly. The 202 * compromise is to force it to zero here. 203 */ 204 sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize); 205 sav->iv = (caddr_t) malloc(sav->ivlen, M_XDATA, M_WAITOK); 206 if (sav->iv == NULL) { 207 DPRINTF(("esp_init: no memory for IV\n")); 208 return EINVAL; 209 } 210 key_randomfill(sav->iv, sav->ivlen); /*XXX*/ 211 212 /* 213 * Setup AH-related state. 214 */ 215 if (sav->alg_auth != 0) { 216 error = ah_init0(sav, xsp, &cria); 217 if (error) 218 return error; 219 } 220 221 /* NB: override anything set in ah_init0 */ 222 sav->tdb_xform = xsp; 223 sav->tdb_encalgxform = txform; 224 225 /* Initialize crypto session. */ 226 bzero(&crie, sizeof (crie)); 227 crie.cri_alg = sav->tdb_encalgxform->type; 228 crie.cri_klen = _KEYBITS(sav->key_enc); 229 crie.cri_key = _KEYBUF(sav->key_enc); 230 /* XXX Rounds ? */ 231 232 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 233 /* init both auth & enc */ 234 crie.cri_next = &cria; 235 error = crypto_newsession(&sav->tdb_cryptoid, 236 &crie, crypto_support); 237 } else if (sav->tdb_encalgxform) { 238 error = crypto_newsession(&sav->tdb_cryptoid, 239 &crie, crypto_support); 240 } else if (sav->tdb_authalgxform) { 241 error = crypto_newsession(&sav->tdb_cryptoid, 242 &cria, crypto_support); 243 } else { 244 /* XXX cannot happen? */ 245 DPRINTF(("esp_init: no encoding OR authentication xform!\n")); 246 error = EINVAL; 247 } 248 return error; 249 } 250 251 /* 252 * Paranoia. 253 */ 254 static int 255 esp_zeroize(struct secasvar *sav) 256 { 257 /* NB: ah_zerorize free's the crypto session state */ 258 int error = ah_zeroize(sav); 259 260 if (sav->key_enc) 261 bzero(_KEYBUF(sav->key_enc), _KEYLEN(sav->key_enc)); 262 /* NB: sav->iv is freed elsewhere, even though we malloc it! */ 263 sav->tdb_encalgxform = NULL; 264 sav->tdb_xform = NULL; 265 return error; 266 } 267 268 /* 269 * ESP input processing, called (eventually) through the protocol switch. 270 */ 271 static int 272 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 273 { 274 struct auth_hash *esph; 275 struct enc_xform *espx; 276 struct tdb_ident *tdbi; 277 struct tdb_crypto *tc; 278 int plen, alen, hlen; 279 struct m_tag *mtag; 280 struct newesp *esp; 281 282 struct cryptodesc *crde; 283 struct cryptop *crp; 284 285 IPSEC_SPLASSERT_SOFTNET("esp_input"); 286 287 IPSEC_ASSERT(sav != NULL, ("esp_input: null SA")); 288 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 289 ("esp_input: null encoding xform")); 290 IPSEC_ASSERT((skip&3) == 0 && (m->m_pkthdr.len&3) == 0, 291 ("esp_input: misaligned packet, skip %u pkt len %u", 292 skip, m->m_pkthdr.len)); 293 294 /* XXX don't pullup, just copy header */ 295 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 296 297 esph = sav->tdb_authalgxform; 298 espx = sav->tdb_encalgxform; 299 300 /* Determine the ESP header length */ 301 if (sav->flags & SADB_X_EXT_OLD) 302 hlen = sizeof (struct esp) + sav->ivlen; 303 else 304 hlen = sizeof (struct newesp) + sav->ivlen; 305 /* Authenticator hash size */ 306 alen = esph ? AH_HMAC_HASHLEN : 0; 307 308 /* 309 * Verify payload length is multiple of encryption algorithm 310 * block size. 311 * 312 * NB: This works for the null algorithm because the blocksize 313 * is 4 and all packets must be 4-byte aligned regardless 314 * of the algorithm. 315 */ 316 plen = m->m_pkthdr.len - (skip + hlen + alen); 317 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 318 DPRINTF(("esp_input: " 319 "payload of %d octets not a multiple of %d octets," 320 " SA %s/%08lx\n", 321 plen, espx->blocksize, 322 ipsec_address(&sav->sah->saidx.dst), 323 (u_long) ntohl(sav->spi))); 324 espstat.esps_badilen++; 325 m_freem(m); 326 return EINVAL; 327 } 328 329 /* 330 * Check sequence number. 331 */ 332 if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) { 333 DPRINTF(("esp_input: packet replay check for %s\n", 334 ipsec_logsastr(sav))); /*XXX*/ 335 espstat.esps_replay++; 336 m_freem(m); 337 return ENOBUFS; /*XXX*/ 338 } 339 340 /* Update the counters */ 341 espstat.esps_ibytes += m->m_pkthdr.len - skip - hlen - alen; 342 343 /* Find out if we've already done crypto */ 344 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL); 345 mtag != NULL; 346 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) { 347 tdbi = (struct tdb_ident *) (mtag + 1); 348 if (tdbi->proto == sav->sah->saidx.proto && 349 tdbi->spi == sav->spi && 350 !bcmp(&tdbi->dst, &sav->sah->saidx.dst, 351 sizeof(union sockaddr_union))) 352 break; 353 } 354 355 /* Get crypto descriptors */ 356 crp = crypto_getreq(esph && espx ? 2 : 1); 357 if (crp == NULL) { 358 DPRINTF(("esp_input: failed to acquire crypto descriptors\n")); 359 espstat.esps_crypto++; 360 m_freem(m); 361 return ENOBUFS; 362 } 363 364 /* Get IPsec-specific opaque pointer */ 365 if (esph == NULL || mtag != NULL) 366 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 367 M_XDATA, M_NOWAIT|M_ZERO); 368 else 369 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen, 370 M_XDATA, M_NOWAIT|M_ZERO); 371 if (tc == NULL) { 372 crypto_freereq(crp); 373 DPRINTF(("esp_input: failed to allocate tdb_crypto\n")); 374 espstat.esps_crypto++; 375 m_freem(m); 376 return ENOBUFS; 377 } 378 379 tc->tc_ptr = (caddr_t) mtag; 380 381 if (esph) { 382 struct cryptodesc *crda = crp->crp_desc; 383 384 IPSEC_ASSERT(crda != NULL, ("esp_input: null ah crypto descriptor")); 385 386 /* Authentication descriptor */ 387 crda->crd_skip = skip; 388 crda->crd_len = m->m_pkthdr.len - (skip + alen); 389 crda->crd_inject = m->m_pkthdr.len - alen; 390 391 crda->crd_alg = esph->type; 392 crda->crd_key = _KEYBUF(sav->key_auth); 393 crda->crd_klen = _KEYBITS(sav->key_auth); 394 395 /* Copy the authenticator */ 396 if (mtag == NULL) 397 m_copydata(m, m->m_pkthdr.len - alen, alen, 398 (caddr_t) (tc + 1)); 399 400 /* Chain authentication request */ 401 crde = crda->crd_next; 402 } else { 403 crde = crp->crp_desc; 404 } 405 406 /* Crypto operation descriptor */ 407 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 408 crp->crp_flags = CRYPTO_F_IMBUF; 409 crp->crp_buf = (caddr_t) m; 410 crp->crp_callback = esp_input_cb; 411 crp->crp_sid = sav->tdb_cryptoid; 412 crp->crp_opaque = (caddr_t) tc; 413 414 /* These are passed as-is to the callback */ 415 tc->tc_spi = sav->spi; 416 tc->tc_dst = sav->sah->saidx.dst; 417 tc->tc_proto = sav->sah->saidx.proto; 418 tc->tc_protoff = protoff; 419 tc->tc_skip = skip; 420 421 /* Decryption descriptor */ 422 if (espx) { 423 IPSEC_ASSERT(crde != NULL, ("esp_input: null esp crypto descriptor")); 424 crde->crd_skip = skip + hlen; 425 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 426 crde->crd_inject = skip + hlen - sav->ivlen; 427 428 crde->crd_alg = espx->type; 429 crde->crd_key = _KEYBUF(sav->key_enc); 430 crde->crd_klen = _KEYBITS(sav->key_enc); 431 /* XXX Rounds ? */ 432 } 433 434 if (mtag == NULL) 435 return crypto_dispatch(crp); 436 else 437 return esp_input_cb(crp); 438 } 439 440 #ifdef INET6 441 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \ 442 if (saidx->dst.sa.sa_family == AF_INET6) { \ 443 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \ 444 } else { \ 445 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \ 446 } \ 447 } while (0) 448 #else 449 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \ 450 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag)) 451 #endif 452 453 /* 454 * ESP input callback from the crypto driver. 455 */ 456 static int 457 esp_input_cb(struct cryptop *crp) 458 { 459 u_int8_t lastthree[3], aalg[AH_HMAC_HASHLEN]; 460 int s, hlen, skip, protoff, error; 461 struct mbuf *m; 462 struct cryptodesc *crd; 463 struct auth_hash *esph; 464 struct enc_xform *espx; 465 struct tdb_crypto *tc; 466 struct m_tag *mtag; 467 struct secasvar *sav; 468 struct secasindex *saidx; 469 caddr_t ptr; 470 471 crd = crp->crp_desc; 472 IPSEC_ASSERT(crd != NULL, ("esp_input_cb: null crypto descriptor!")); 473 474 tc = (struct tdb_crypto *) crp->crp_opaque; 475 IPSEC_ASSERT(tc != NULL, ("esp_input_cb: null opaque crypto data area!")); 476 skip = tc->tc_skip; 477 protoff = tc->tc_protoff; 478 mtag = (struct m_tag *) tc->tc_ptr; 479 m = (struct mbuf *) crp->crp_buf; 480 481 s = splsoftnet(); 482 483 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 484 if (sav == NULL) { 485 espstat.esps_notdb++; 486 DPRINTF(("esp_input_cb: SA expired while in crypto " 487 "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst), 488 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 489 error = ENOBUFS; /*XXX*/ 490 goto bad; 491 } 492 493 saidx = &sav->sah->saidx; 494 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 495 saidx->dst.sa.sa_family == AF_INET6, 496 ("ah_input_cb: unexpected protocol family %u", 497 saidx->dst.sa.sa_family)); 498 499 esph = sav->tdb_authalgxform; 500 espx = sav->tdb_encalgxform; 501 502 /* Check for crypto errors */ 503 if (crp->crp_etype) { 504 /* Reset the session ID */ 505 if (sav->tdb_cryptoid != 0) 506 sav->tdb_cryptoid = crp->crp_sid; 507 508 if (crp->crp_etype == EAGAIN) { 509 KEY_FREESAV(&sav); 510 splx(s); 511 return crypto_dispatch(crp); 512 } 513 514 espstat.esps_noxform++; 515 DPRINTF(("esp_input_cb: crypto error %d\n", crp->crp_etype)); 516 error = crp->crp_etype; 517 goto bad; 518 } 519 520 /* Shouldn't happen... */ 521 if (m == NULL) { 522 espstat.esps_crypto++; 523 DPRINTF(("esp_input_cb: bogus returned buffer from crypto\n")); 524 error = EINVAL; 525 goto bad; 526 } 527 espstat.esps_hist[sav->alg_enc]++; 528 529 /* If authentication was performed, check now. */ 530 if (esph != NULL) { 531 /* 532 * If we have a tag, it means an IPsec-aware NIC did 533 * the verification for us. Otherwise we need to 534 * check the authentication calculation. 535 */ 536 ahstat.ahs_hist[sav->alg_auth]++; 537 if (mtag == NULL) { 538 /* Copy the authenticator from the packet */ 539 m_copydata(m, m->m_pkthdr.len - esph->authsize, 540 esph->authsize, aalg); 541 542 ptr = (caddr_t) (tc + 1); 543 544 /* Verify authenticator */ 545 if (bcmp(ptr, aalg, esph->authsize) != 0) { 546 DPRINTF(("esp_input_cb: " 547 "authentication hash mismatch for packet in SA %s/%08lx\n", 548 ipsec_address(&saidx->dst), 549 (u_long) ntohl(sav->spi))); 550 espstat.esps_badauth++; 551 error = EACCES; 552 goto bad; 553 } 554 } 555 556 /* Remove trailing authenticator */ 557 m_adj(m, -(esph->authsize)); 558 } 559 560 /* Release the crypto descriptors */ 561 free(tc, M_XDATA), tc = NULL; 562 crypto_freereq(crp), crp = NULL; 563 564 /* 565 * Packet is now decrypted. 566 */ 567 m->m_flags |= M_DECRYPTED; 568 569 /* Determine the ESP header length */ 570 if (sav->flags & SADB_X_EXT_OLD) 571 hlen = sizeof (struct esp) + sav->ivlen; 572 else 573 hlen = sizeof (struct newesp) + sav->ivlen; 574 575 /* Remove the ESP header and IV from the mbuf. */ 576 error = m_striphdr(m, skip, hlen); 577 if (error) { 578 espstat.esps_hdrops++; 579 DPRINTF(("esp_input_cb: bad mbuf chain, SA %s/%08lx\n", 580 ipsec_address(&sav->sah->saidx.dst), 581 (u_long) ntohl(sav->spi))); 582 goto bad; 583 } 584 585 /* Save the last three bytes of decrypted data */ 586 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 587 588 /* Verify pad length */ 589 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 590 espstat.esps_badilen++; 591 DPRINTF(("esp_input_cb: invalid padding length %d " 592 "for %u byte packet in SA %s/%08lx\n", 593 lastthree[1], m->m_pkthdr.len - skip, 594 ipsec_address(&sav->sah->saidx.dst), 595 (u_long) ntohl(sav->spi))); 596 error = EINVAL; 597 goto bad; 598 } 599 600 /* Verify correct decryption by checking the last padding bytes */ 601 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 602 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 603 espstat.esps_badenc++; 604 DPRINTF(("esp_input_cb: decryption failed " 605 "for packet in SA %s/%08lx\n", 606 ipsec_address(&sav->sah->saidx.dst), 607 (u_long) ntohl(sav->spi))); 608 DPRINTF(("esp_input_cb: %x %x\n", lastthree[0], lastthree[1])); 609 error = EINVAL; 610 goto bad; 611 } 612 } 613 614 /* Trim the mbuf chain to remove trailing authenticator and padding */ 615 m_adj(m, -(lastthree[1] + 2)); 616 617 /* Restore the Next Protocol field */ 618 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 619 620 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag); 621 622 KEY_FREESAV(&sav); 623 splx(s); 624 return error; 625 bad: 626 if (sav) 627 KEY_FREESAV(&sav); 628 splx(s); 629 if (m != NULL) 630 m_freem(m); 631 if (tc != NULL) 632 free(tc, M_XDATA); 633 if (crp != NULL) 634 crypto_freereq(crp); 635 return error; 636 } 637 638 /* 639 * ESP output routine, called by ipsec[46]_process_packet(). 640 */ 641 static int 642 esp_output( 643 struct mbuf *m, 644 struct ipsecrequest *isr, 645 struct mbuf **mp, 646 int skip, 647 int protoff 648 ) 649 { 650 struct enc_xform *espx; 651 struct auth_hash *esph; 652 int hlen, rlen, plen, padding, blks, alen, i, roff; 653 struct mbuf *mo = (struct mbuf *) NULL; 654 struct tdb_crypto *tc; 655 struct secasvar *sav; 656 struct secasindex *saidx; 657 unsigned char *pad; 658 u_int8_t prot; 659 int error, maxpacketsize; 660 661 struct cryptodesc *crde = NULL, *crda = NULL; 662 struct cryptop *crp; 663 664 IPSEC_SPLASSERT_SOFTNET("esp_output"); 665 666 sav = isr->sav; 667 IPSEC_ASSERT(sav != NULL, ("esp_output: null SA")); 668 esph = sav->tdb_authalgxform; 669 espx = sav->tdb_encalgxform; 670 IPSEC_ASSERT(espx != NULL, ("esp_output: null encoding xform")); 671 672 if (sav->flags & SADB_X_EXT_OLD) 673 hlen = sizeof (struct esp) + sav->ivlen; 674 else 675 hlen = sizeof (struct newesp) + sav->ivlen; 676 677 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 678 /* 679 * NB: The null encoding transform has a blocksize of 4 680 * so that headers are properly aligned. 681 */ 682 blks = espx->blocksize; /* IV blocksize */ 683 684 /* XXX clamp padding length a la KAME??? */ 685 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 686 plen = rlen + padding; /* Padded payload length. */ 687 688 if (esph) 689 alen = AH_HMAC_HASHLEN; 690 else 691 alen = 0; 692 693 espstat.esps_output++; 694 695 saidx = &sav->sah->saidx; 696 /* Check for maximum packet size violations. */ 697 switch (saidx->dst.sa.sa_family) { 698 #ifdef INET 699 case AF_INET: 700 maxpacketsize = IP_MAXPACKET; 701 break; 702 #endif /* INET */ 703 #ifdef INET6 704 case AF_INET6: 705 maxpacketsize = IPV6_MAXPACKET; 706 break; 707 #endif /* INET6 */ 708 default: 709 DPRINTF(("esp_output: unknown/unsupported protocol " 710 "family %d, SA %s/%08lx\n", 711 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst), 712 (u_long) ntohl(sav->spi))); 713 espstat.esps_nopf++; 714 error = EPFNOSUPPORT; 715 goto bad; 716 } 717 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 718 DPRINTF(("esp_output: packet in SA %s/%08lx got too big " 719 "(len %u, max len %u)\n", 720 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi), 721 skip + hlen + rlen + padding + alen, maxpacketsize)); 722 espstat.esps_toobig++; 723 error = EMSGSIZE; 724 goto bad; 725 } 726 727 /* Update the counters. */ 728 espstat.esps_obytes += m->m_pkthdr.len - skip; 729 730 m = m_clone(m); 731 if (m == NULL) { 732 DPRINTF(("esp_output: cannot clone mbuf chain, SA %s/%08lx\n", 733 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 734 espstat.esps_hdrops++; 735 error = ENOBUFS; 736 goto bad; 737 } 738 739 /* Inject ESP header. */ 740 mo = m_makespace(m, skip, hlen, &roff); 741 if (mo == NULL) { 742 DPRINTF(("esp_output: failed to inject %u byte ESP hdr for SA " 743 "%s/%08lx\n", 744 hlen, ipsec_address(&saidx->dst), 745 (u_long) ntohl(sav->spi))); 746 espstat.esps_hdrops++; /* XXX diffs from openbsd */ 747 error = ENOBUFS; 748 goto bad; 749 } 750 751 /* Initialize ESP header. */ 752 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t)); 753 if (sav->replay) { 754 u_int32_t replay = htonl(++(sav->replay->count)); 755 bcopy((caddr_t) &replay, 756 mtod(mo, caddr_t) + roff + sizeof(u_int32_t), 757 sizeof(u_int32_t)); 758 } 759 760 /* 761 * Add padding -- better to do it ourselves than use the crypto engine, 762 * although if/when we support compression, we'd have to do that. 763 */ 764 pad = (u_char *) m_pad(m, padding + alen); 765 if (pad == NULL) { 766 DPRINTF(("esp_output: m_pad failed for SA %s/%08lx\n", 767 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 768 m = NULL; /* NB: free'd by m_pad */ 769 error = ENOBUFS; 770 goto bad; 771 } 772 773 /* 774 * Add padding: random, zero, or self-describing. 775 * XXX catch unexpected setting 776 */ 777 switch (sav->flags & SADB_X_EXT_PMASK) { 778 case SADB_X_EXT_PRAND: 779 (void) read_random(pad, padding - 2); 780 break; 781 case SADB_X_EXT_PZERO: 782 bzero(pad, padding - 2); 783 break; 784 case SADB_X_EXT_PSEQ: 785 for (i = 0; i < padding - 2; i++) 786 pad[i] = i+1; 787 break; 788 } 789 790 /* Fix padding length and Next Protocol in padding itself. */ 791 pad[padding - 2] = padding - 2; 792 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 793 794 /* Fix Next Protocol in IPv4/IPv6 header. */ 795 prot = IPPROTO_ESP; 796 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 797 798 /* Get crypto descriptors. */ 799 crp = crypto_getreq(esph && espx ? 2 : 1); 800 if (crp == NULL) { 801 DPRINTF(("esp_output: failed to acquire crypto descriptors\n")); 802 espstat.esps_crypto++; 803 error = ENOBUFS; 804 goto bad; 805 } 806 807 if (espx) { 808 crde = crp->crp_desc; 809 crda = crde->crd_next; 810 811 /* Encryption descriptor. */ 812 crde->crd_skip = skip + hlen; 813 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 814 crde->crd_flags = CRD_F_ENCRYPT; 815 crde->crd_inject = skip + hlen - sav->ivlen; 816 817 /* Encryption operation. */ 818 crde->crd_alg = espx->type; 819 crde->crd_key = _KEYBUF(sav->key_enc); 820 crde->crd_klen = _KEYBITS(sav->key_enc); 821 /* XXX Rounds ? */ 822 } else 823 crda = crp->crp_desc; 824 825 /* IPsec-specific opaque crypto info. */ 826 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 827 M_XDATA, M_NOWAIT|M_ZERO); 828 if (tc == NULL) { 829 crypto_freereq(crp); 830 DPRINTF(("esp_output: failed to allocate tdb_crypto\n")); 831 espstat.esps_crypto++; 832 error = ENOBUFS; 833 goto bad; 834 } 835 836 /* Callback parameters */ 837 tc->tc_isr = isr; 838 tc->tc_spi = sav->spi; 839 tc->tc_dst = saidx->dst; 840 tc->tc_proto = saidx->proto; 841 842 /* Crypto operation descriptor. */ 843 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 844 crp->crp_flags = CRYPTO_F_IMBUF; 845 crp->crp_buf = (caddr_t) m; 846 crp->crp_callback = esp_output_cb; 847 crp->crp_opaque = (caddr_t) tc; 848 crp->crp_sid = sav->tdb_cryptoid; 849 850 if (esph) { 851 /* Authentication descriptor. */ 852 crda->crd_skip = skip; 853 crda->crd_len = m->m_pkthdr.len - (skip + alen); 854 crda->crd_inject = m->m_pkthdr.len - alen; 855 856 /* Authentication operation. */ 857 crda->crd_alg = esph->type; 858 crda->crd_key = _KEYBUF(sav->key_auth); 859 crda->crd_klen = _KEYBITS(sav->key_auth); 860 } 861 862 return crypto_dispatch(crp); 863 bad: 864 if (m) 865 m_freem(m); 866 return (error); 867 } 868 869 /* 870 * ESP output callback from the crypto driver. 871 */ 872 static int 873 esp_output_cb(struct cryptop *crp) 874 { 875 struct tdb_crypto *tc; 876 struct ipsecrequest *isr; 877 struct secasvar *sav; 878 struct mbuf *m; 879 int s, err, error; 880 881 tc = (struct tdb_crypto *) crp->crp_opaque; 882 IPSEC_ASSERT(tc != NULL, ("esp_output_cb: null opaque data area!")); 883 m = (struct mbuf *) crp->crp_buf; 884 885 s = splsoftnet(); 886 887 isr = tc->tc_isr; 888 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 889 if (sav == NULL) { 890 espstat.esps_notdb++; 891 DPRINTF(("esp_output_cb: SA expired while in crypto " 892 "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst), 893 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 894 error = ENOBUFS; /*XXX*/ 895 goto bad; 896 } 897 IPSEC_ASSERT(isr->sav == sav, 898 ("esp_output_cb: SA changed was %p now %p\n", isr->sav, sav)); 899 900 /* Check for crypto errors. */ 901 if (crp->crp_etype) { 902 /* Reset session ID. */ 903 if (sav->tdb_cryptoid != 0) 904 sav->tdb_cryptoid = crp->crp_sid; 905 906 if (crp->crp_etype == EAGAIN) { 907 KEY_FREESAV(&sav); 908 splx(s); 909 return crypto_dispatch(crp); 910 } 911 912 espstat.esps_noxform++; 913 DPRINTF(("esp_output_cb: crypto error %d\n", crp->crp_etype)); 914 error = crp->crp_etype; 915 goto bad; 916 } 917 918 /* Shouldn't happen... */ 919 if (m == NULL) { 920 espstat.esps_crypto++; 921 DPRINTF(("esp_output_cb: bogus returned buffer from crypto\n")); 922 error = EINVAL; 923 goto bad; 924 } 925 espstat.esps_hist[sav->alg_enc]++; 926 if (sav->tdb_authalgxform != NULL) 927 ahstat.ahs_hist[sav->alg_auth]++; 928 929 /* Release crypto descriptors. */ 930 free(tc, M_XDATA); 931 crypto_freereq(crp); 932 933 /* NB: m is reclaimed by ipsec_process_done. */ 934 err = ipsec_process_done(m, isr); 935 KEY_FREESAV(&sav); 936 splx(s); 937 return err; 938 bad: 939 if (sav) 940 KEY_FREESAV(&sav); 941 splx(s); 942 if (m) 943 m_freem(m); 944 free(tc, M_XDATA); 945 crypto_freereq(crp); 946 return error; 947 } 948 949 static struct xformsw esp_xformsw = { 950 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 951 esp_init, esp_zeroize, esp_input, 952 esp_output 953 }; 954 955 INITFN void 956 esp_attach(void) 957 { 958 #define MAXIV(xform) \ 959 if (xform.blocksize > esp_max_ivlen) \ 960 esp_max_ivlen = xform.blocksize \ 961 962 esp_max_ivlen = 0; 963 MAXIV(enc_xform_des); /* SADB_EALG_DESCBC */ 964 MAXIV(enc_xform_3des); /* SADB_EALG_3DESCBC */ 965 MAXIV(enc_xform_rijndael128); /* SADB_X_EALG_AES */ 966 MAXIV(enc_xform_blf); /* SADB_X_EALG_BLOWFISHCBC */ 967 MAXIV(enc_xform_cast5); /* SADB_X_EALG_CAST128CBC */ 968 MAXIV(enc_xform_skipjack); /* SADB_X_EALG_SKIPJACK */ 969 MAXIV(enc_xform_null); /* SADB_EALG_NULL */ 970 971 xform_register(&esp_xformsw); 972 #undef MAXIV 973 } 974 #ifdef __FreeBSD__ 975 SYSINIT(esp_xform_init, SI_SUB_DRIVERS, SI_ORDER_FIRST, esp_attach, NULL) 976 #else 977 #endif 978