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 | CRYPTO_F_CBIFSYNC; 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 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 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 472 if (sav == NULL) { 473 espstat.esps_notdb++; 474 DPRINTF(("esp_input_cb: SA expired while in crypto " 475 "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst), 476 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 477 error = ENOBUFS; /*XXX*/ 478 goto bad; 479 } 480 481 saidx = &sav->sah->saidx; 482 KASSERT(saidx->dst.sa.sa_family == AF_INET || 483 saidx->dst.sa.sa_family == AF_INET6, 484 ("ah_input_cb: unexpected protocol family %u", 485 saidx->dst.sa.sa_family)); 486 487 esph = sav->tdb_authalgxform; 488 espx = sav->tdb_encalgxform; 489 490 /* Check for crypto errors */ 491 if (crp->crp_etype) { 492 /* Reset the session ID */ 493 if (sav->tdb_cryptoid != 0) 494 sav->tdb_cryptoid = crp->crp_sid; 495 496 if (crp->crp_etype == EAGAIN) { 497 KEY_FREESAV(&sav); 498 return crypto_dispatch(crp); 499 } 500 501 espstat.esps_noxform++; 502 DPRINTF(("esp_input_cb: crypto error %d\n", crp->crp_etype)); 503 error = crp->crp_etype; 504 goto bad; 505 } 506 507 /* Shouldn't happen... */ 508 if (m == NULL) { 509 espstat.esps_crypto++; 510 DPRINTF(("esp_input_cb: bogus returned buffer from crypto\n")); 511 error = EINVAL; 512 goto bad; 513 } 514 espstat.esps_hist[sav->alg_enc]++; 515 516 /* If authentication was performed, check now. */ 517 if (esph != NULL) { 518 /* 519 * If we have a tag, it means an IPsec-aware NIC did 520 * the verification for us. Otherwise we need to 521 * check the authentication calculation. 522 */ 523 ahstat.ahs_hist[sav->alg_auth]++; 524 if (mtag == NULL) { 525 /* Copy the authenticator from the packet */ 526 m_copydata(m, m->m_pkthdr.len - esph->authsize, 527 esph->authsize, aalg); 528 529 ptr = (caddr_t) (tc + 1); 530 531 /* Verify authenticator */ 532 if (bcmp(ptr, aalg, esph->authsize) != 0) { 533 DPRINTF(("esp_input_cb: " 534 "authentication hash mismatch for packet in SA %s/%08lx\n", 535 ipsec_address(&saidx->dst), 536 (u_long) ntohl(sav->spi))); 537 espstat.esps_badauth++; 538 error = EACCES; 539 goto bad; 540 } 541 } 542 543 /* Remove trailing authenticator */ 544 m_adj(m, -(esph->authsize)); 545 } 546 547 /* Release the crypto descriptors */ 548 free(tc, M_XDATA), tc = NULL; 549 crypto_freereq(crp), crp = NULL; 550 551 /* 552 * Packet is now decrypted. 553 */ 554 m->m_flags |= M_DECRYPTED; 555 556 /* Determine the ESP header length */ 557 if (sav->flags & SADB_X_EXT_OLD) 558 hlen = sizeof (struct esp) + sav->ivlen; 559 else 560 hlen = sizeof (struct newesp) + sav->ivlen; 561 562 /* Remove the ESP header and IV from the mbuf. */ 563 error = m_striphdr(m, skip, hlen); 564 if (error) { 565 espstat.esps_hdrops++; 566 DPRINTF(("esp_input_cb: bad mbuf chain, SA %s/%08lx\n", 567 ipsec_address(&sav->sah->saidx.dst), 568 (u_long) ntohl(sav->spi))); 569 goto bad; 570 } 571 572 /* Save the last three bytes of decrypted data */ 573 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 574 575 /* Verify pad length */ 576 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 577 espstat.esps_badilen++; 578 DPRINTF(("esp_input_cb: invalid padding length %d " 579 "for %u byte packet in SA %s/%08lx\n", 580 lastthree[1], m->m_pkthdr.len - skip, 581 ipsec_address(&sav->sah->saidx.dst), 582 (u_long) ntohl(sav->spi))); 583 error = EINVAL; 584 goto bad; 585 } 586 587 /* Verify correct decryption by checking the last padding bytes */ 588 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 589 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 590 espstat.esps_badenc++; 591 DPRINTF(("esp_input_cb: decryption failed " 592 "for packet in SA %s/%08lx\n", 593 ipsec_address(&sav->sah->saidx.dst), 594 (u_long) ntohl(sav->spi))); 595 DPRINTF(("esp_input_cb: %x %x\n", lastthree[0], lastthree[1])); 596 error = EINVAL; 597 goto bad; 598 } 599 } 600 601 /* Trim the mbuf chain to remove trailing authenticator and padding */ 602 m_adj(m, -(lastthree[1] + 2)); 603 604 /* Restore the Next Protocol field */ 605 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 606 607 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag); 608 609 KEY_FREESAV(&sav); 610 return error; 611 bad: 612 if (sav) 613 KEY_FREESAV(&sav); 614 if (m != NULL) 615 m_freem(m); 616 if (tc != NULL) 617 free(tc, M_XDATA); 618 if (crp != NULL) 619 crypto_freereq(crp); 620 return error; 621 } 622 623 /* 624 * ESP output routine, called by ipsec[46]_process_packet(). 625 */ 626 static int 627 esp_output( 628 struct mbuf *m, 629 struct ipsecrequest *isr, 630 struct mbuf **mp, 631 int skip, 632 int protoff 633 ) 634 { 635 struct enc_xform *espx; 636 struct auth_hash *esph; 637 int hlen, rlen, plen, padding, blks, alen, i, roff; 638 struct mbuf *mo = (struct mbuf *) NULL; 639 struct tdb_crypto *tc; 640 struct secasvar *sav; 641 struct secasindex *saidx; 642 unsigned char *pad; 643 u_int8_t prot; 644 int error, maxpacketsize; 645 646 struct cryptodesc *crde = NULL, *crda = NULL; 647 struct cryptop *crp; 648 649 #if 0 650 SPLASSERT(net, "esp_output"); 651 #endif 652 653 sav = isr->sav; 654 KASSERT(sav != NULL, ("esp_output: null SA")); 655 esph = sav->tdb_authalgxform; 656 espx = sav->tdb_encalgxform; 657 KASSERT(espx != NULL, ("esp_output: null encoding xform")); 658 659 if (sav->flags & SADB_X_EXT_OLD) 660 hlen = sizeof (struct esp) + sav->ivlen; 661 else 662 hlen = sizeof (struct newesp) + sav->ivlen; 663 664 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 665 /* 666 * NB: The null encoding transform has a blocksize of 4 667 * so that headers are properly aligned. 668 */ 669 blks = espx->blocksize; /* IV blocksize */ 670 671 /* XXX clamp padding length a la KAME??? */ 672 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 673 plen = rlen + padding; /* Padded payload length. */ 674 675 if (esph) 676 alen = AH_HMAC_HASHLEN; 677 else 678 alen = 0; 679 680 espstat.esps_output++; 681 682 saidx = &sav->sah->saidx; 683 /* Check for maximum packet size violations. */ 684 switch (saidx->dst.sa.sa_family) { 685 #ifdef INET 686 case AF_INET: 687 maxpacketsize = IP_MAXPACKET; 688 break; 689 #endif /* INET */ 690 #ifdef INET6 691 case AF_INET6: 692 maxpacketsize = IPV6_MAXPACKET; 693 break; 694 #endif /* INET6 */ 695 default: 696 DPRINTF(("esp_output: unknown/unsupported protocol " 697 "family %d, SA %s/%08lx\n", 698 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst), 699 (u_long) ntohl(sav->spi))); 700 espstat.esps_nopf++; 701 error = EPFNOSUPPORT; 702 goto bad; 703 } 704 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 705 DPRINTF(("esp_output: packet in SA %s/%08lx got too big " 706 "(len %u, max len %u)\n", 707 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi), 708 skip + hlen + rlen + padding + alen, maxpacketsize)); 709 espstat.esps_toobig++; 710 error = EMSGSIZE; 711 goto bad; 712 } 713 714 /* Update the counters. */ 715 espstat.esps_obytes += m->m_pkthdr.len - skip; 716 717 m = m_clone(m); 718 if (m == NULL) { 719 DPRINTF(("esp_output: cannot clone mbuf chain, SA %s/%08lx\n", 720 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 721 espstat.esps_hdrops++; 722 error = ENOBUFS; 723 goto bad; 724 } 725 726 /* Inject ESP header. */ 727 mo = m_makespace(m, skip, hlen, &roff); 728 if (mo == NULL) { 729 DPRINTF(("esp_output: failed to inject %u byte ESP hdr for SA " 730 "%s/%08lx\n", 731 hlen, ipsec_address(&saidx->dst), 732 (u_long) ntohl(sav->spi))); 733 espstat.esps_hdrops++; /* XXX diffs from openbsd */ 734 error = ENOBUFS; 735 goto bad; 736 } 737 738 /* Initialize ESP header. */ 739 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t)); 740 if (sav->replay) { 741 u_int32_t replay = htonl(++(sav->replay->count)); 742 bcopy((caddr_t) &replay, 743 mtod(mo, caddr_t) + roff + sizeof(u_int32_t), 744 sizeof(u_int32_t)); 745 } 746 747 /* 748 * Add padding -- better to do it ourselves than use the crypto engine, 749 * although if/when we support compression, we'd have to do that. 750 */ 751 pad = (u_char *) m_pad(m, padding + alen); 752 if (pad == NULL) { 753 DPRINTF(("esp_output: m_pad failed for SA %s/%08lx\n", 754 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 755 m = NULL; /* NB: free'd by m_pad */ 756 error = ENOBUFS; 757 goto bad; 758 } 759 760 /* 761 * Add padding: random, zero, or self-describing. 762 * XXX catch unexpected setting 763 */ 764 switch (sav->flags & SADB_X_EXT_PMASK) { 765 case SADB_X_EXT_PRAND: 766 (void) read_random(pad, padding - 2); 767 break; 768 case SADB_X_EXT_PZERO: 769 bzero(pad, padding - 2); 770 break; 771 case SADB_X_EXT_PSEQ: 772 for (i = 0; i < padding - 2; i++) 773 pad[i] = i+1; 774 break; 775 } 776 777 /* Fix padding length and Next Protocol in padding itself. */ 778 pad[padding - 2] = padding - 2; 779 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 780 781 /* Fix Next Protocol in IPv4/IPv6 header. */ 782 prot = IPPROTO_ESP; 783 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 784 785 /* Get crypto descriptors. */ 786 crp = crypto_getreq(esph && espx ? 2 : 1); 787 if (crp == NULL) { 788 DPRINTF(("esp_output: failed to acquire crypto descriptors\n")); 789 espstat.esps_crypto++; 790 error = ENOBUFS; 791 goto bad; 792 } 793 794 if (espx) { 795 crde = crp->crp_desc; 796 crda = crde->crd_next; 797 798 /* Encryption descriptor. */ 799 crde->crd_skip = skip + hlen; 800 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 801 crde->crd_flags = CRD_F_ENCRYPT; 802 crde->crd_inject = skip + hlen - sav->ivlen; 803 804 /* Encryption operation. */ 805 crde->crd_alg = espx->type; 806 crde->crd_key = _KEYBUF(sav->key_enc); 807 crde->crd_klen = _KEYBITS(sav->key_enc); 808 /* XXX Rounds ? */ 809 } else 810 crda = crp->crp_desc; 811 812 /* IPsec-specific opaque crypto info. */ 813 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 814 M_XDATA, M_NOWAIT|M_ZERO); 815 if (tc == NULL) { 816 crypto_freereq(crp); 817 DPRINTF(("esp_output: failed to allocate tdb_crypto\n")); 818 espstat.esps_crypto++; 819 error = ENOBUFS; 820 goto bad; 821 } 822 823 /* Callback parameters */ 824 tc->tc_isr = isr; 825 tc->tc_spi = sav->spi; 826 tc->tc_dst = saidx->dst; 827 tc->tc_proto = saidx->proto; 828 829 /* Crypto operation descriptor. */ 830 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 831 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 832 crp->crp_buf = (caddr_t) m; 833 crp->crp_callback = esp_output_cb; 834 crp->crp_opaque = (caddr_t) tc; 835 crp->crp_sid = sav->tdb_cryptoid; 836 837 if (esph) { 838 /* Authentication descriptor. */ 839 crda->crd_skip = skip; 840 crda->crd_len = m->m_pkthdr.len - (skip + alen); 841 crda->crd_inject = m->m_pkthdr.len - alen; 842 843 /* Authentication operation. */ 844 crda->crd_alg = esph->type; 845 crda->crd_key = _KEYBUF(sav->key_auth); 846 crda->crd_klen = _KEYBITS(sav->key_auth); 847 } 848 849 return crypto_dispatch(crp); 850 bad: 851 if (m) 852 m_freem(m); 853 return (error); 854 } 855 856 /* 857 * ESP output callback from the crypto driver. 858 */ 859 static int 860 esp_output_cb(struct cryptop *crp) 861 { 862 struct tdb_crypto *tc; 863 struct ipsecrequest *isr; 864 struct secasvar *sav; 865 struct mbuf *m; 866 int err, error; 867 868 tc = (struct tdb_crypto *) crp->crp_opaque; 869 KASSERT(tc != NULL, ("esp_output_cb: null opaque data area!")); 870 m = (struct mbuf *) crp->crp_buf; 871 872 isr = tc->tc_isr; 873 mtx_lock(&isr->lock); 874 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 875 if (sav == NULL) { 876 espstat.esps_notdb++; 877 DPRINTF(("esp_output_cb: SA expired while in crypto " 878 "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst), 879 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 880 error = ENOBUFS; /*XXX*/ 881 goto bad; 882 } 883 KASSERT(isr->sav == sav, 884 ("esp_output_cb: SA changed was %p now %p\n", isr->sav, sav)); 885 886 /* Check for crypto errors. */ 887 if (crp->crp_etype) { 888 /* Reset session ID. */ 889 if (sav->tdb_cryptoid != 0) 890 sav->tdb_cryptoid = crp->crp_sid; 891 892 if (crp->crp_etype == EAGAIN) { 893 KEY_FREESAV(&sav); 894 mtx_unlock(&isr->lock); 895 return crypto_dispatch(crp); 896 } 897 898 espstat.esps_noxform++; 899 DPRINTF(("esp_output_cb: crypto error %d\n", crp->crp_etype)); 900 error = crp->crp_etype; 901 goto bad; 902 } 903 904 /* Shouldn't happen... */ 905 if (m == NULL) { 906 espstat.esps_crypto++; 907 DPRINTF(("esp_output_cb: bogus returned buffer from crypto\n")); 908 error = EINVAL; 909 goto bad; 910 } 911 espstat.esps_hist[sav->alg_enc]++; 912 if (sav->tdb_authalgxform != NULL) 913 ahstat.ahs_hist[sav->alg_auth]++; 914 915 /* Release crypto descriptors. */ 916 free(tc, M_XDATA); 917 crypto_freereq(crp); 918 919 /* NB: m is reclaimed by ipsec_process_done. */ 920 err = ipsec_process_done(m, isr); 921 KEY_FREESAV(&sav); 922 mtx_unlock(&isr->lock); 923 924 return err; 925 bad: 926 if (sav) 927 KEY_FREESAV(&sav); 928 mtx_unlock(&isr->lock); 929 if (m) 930 m_freem(m); 931 free(tc, M_XDATA); 932 crypto_freereq(crp); 933 return error; 934 } 935 936 static struct xformsw esp_xformsw = { 937 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 938 esp_init, esp_zeroize, esp_input, 939 esp_output 940 }; 941 942 static void 943 esp_attach(void) 944 { 945 #define MAXIV(xform) \ 946 if (xform.blocksize > esp_max_ivlen) \ 947 esp_max_ivlen = xform.blocksize \ 948 949 esp_max_ivlen = 0; 950 MAXIV(enc_xform_des); /* SADB_EALG_DESCBC */ 951 MAXIV(enc_xform_3des); /* SADB_EALG_3DESCBC */ 952 MAXIV(enc_xform_rijndael128); /* SADB_X_EALG_AES */ 953 MAXIV(enc_xform_blf); /* SADB_X_EALG_BLOWFISHCBC */ 954 MAXIV(enc_xform_cast5); /* SADB_X_EALG_CAST128CBC */ 955 MAXIV(enc_xform_skipjack); /* SADB_X_EALG_SKIPJACK */ 956 MAXIV(enc_xform_null); /* SADB_EALG_NULL */ 957 958 xform_register(&esp_xformsw); 959 #undef MAXIV 960 } 961 SYSINIT(esp_xform_init, SI_SUB_DRIVERS, SI_ORDER_FIRST, esp_attach, NULL) 962