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