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 #include <sys/vimage.h> 50 51 #include <net/if.h> 52 53 #include <netinet/in.h> 54 #include <netinet/in_systm.h> 55 #include <netinet/ip.h> 56 #include <netinet/ip_ecn.h> 57 #include <netinet/ip6.h> 58 59 #include <net/route.h> 60 #include <netipsec/ipsec.h> 61 #include <netipsec/ah.h> 62 #include <netipsec/ah_var.h> 63 #include <netipsec/esp.h> 64 #include <netipsec/esp_var.h> 65 #include <netipsec/xform.h> 66 67 #ifdef INET6 68 #include <netinet6/ip6_var.h> 69 #include <netipsec/ipsec6.h> 70 #include <netinet6/ip6_ecn.h> 71 #endif 72 73 #include <netipsec/key.h> 74 #include <netipsec/key_debug.h> 75 76 #include <opencrypto/cryptodev.h> 77 #include <opencrypto/xform.h> 78 79 int esp_enable = 1; 80 struct espstat espstat; 81 82 SYSCTL_DECL(_net_inet_esp); 83 SYSCTL_INT(_net_inet_esp, OID_AUTO, 84 esp_enable, CTLFLAG_RW, &esp_enable, 0, ""); 85 SYSCTL_STRUCT(_net_inet_esp, IPSECCTL_STATS, 86 stats, CTLFLAG_RD, &espstat, espstat, ""); 87 88 static int esp_max_ivlen; /* max iv length over all algorithms */ 89 90 static int esp_input_cb(struct cryptop *op); 91 static int esp_output_cb(struct cryptop *crp); 92 93 /* 94 * NB: this is public for use by the PF_KEY support. 95 * NB: if you add support here; be sure to add code to esp_attach below! 96 */ 97 struct enc_xform * 98 esp_algorithm_lookup(int alg) 99 { 100 if (alg >= ESP_ALG_MAX) 101 return NULL; 102 switch (alg) { 103 case SADB_EALG_DESCBC: 104 return &enc_xform_des; 105 case SADB_EALG_3DESCBC: 106 return &enc_xform_3des; 107 case SADB_X_EALG_AES: 108 return &enc_xform_rijndael128; 109 case SADB_X_EALG_BLOWFISHCBC: 110 return &enc_xform_blf; 111 case SADB_X_EALG_CAST128CBC: 112 return &enc_xform_cast5; 113 case SADB_X_EALG_SKIPJACK: 114 return &enc_xform_skipjack; 115 case SADB_EALG_NULL: 116 return &enc_xform_null; 117 case SADB_X_EALG_CAMELLIACBC: 118 return &enc_xform_camellia; 119 } 120 return NULL; 121 } 122 123 size_t 124 esp_hdrsiz(struct secasvar *sav) 125 { 126 size_t size; 127 128 if (sav != NULL) { 129 /*XXX not right for null algorithm--does it matter??*/ 130 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 131 ("SA with null xform")); 132 if (sav->flags & SADB_X_EXT_OLD) 133 size = sizeof (struct esp); 134 else 135 size = sizeof (struct newesp); 136 size += sav->tdb_encalgxform->blocksize + 9; 137 /*XXX need alg check???*/ 138 if (sav->tdb_authalgxform != NULL && sav->replay) 139 size += ah_hdrsiz(sav); 140 } else { 141 /* 142 * base header size 143 * + max iv length for CBC mode 144 * + max pad length 145 * + sizeof (pad length field) 146 * + sizeof (next header field) 147 * + max icv supported. 148 */ 149 size = sizeof (struct newesp) + V_esp_max_ivlen + 9 + 16; 150 } 151 return size; 152 } 153 154 /* 155 * esp_init() is called when an SPI is being set up. 156 */ 157 static int 158 esp_init(struct secasvar *sav, struct xformsw *xsp) 159 { 160 struct enc_xform *txform; 161 struct cryptoini cria, crie; 162 int keylen; 163 int error; 164 165 txform = esp_algorithm_lookup(sav->alg_enc); 166 if (txform == NULL) { 167 DPRINTF(("%s: unsupported encryption algorithm %d\n", 168 __func__, sav->alg_enc)); 169 return EINVAL; 170 } 171 if (sav->key_enc == NULL) { 172 DPRINTF(("%s: no encoding key for %s algorithm\n", 173 __func__, txform->name)); 174 return EINVAL; 175 } 176 if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) { 177 DPRINTF(("%s: 4-byte IV not supported with protocol\n", 178 __func__)); 179 return EINVAL; 180 } 181 keylen = _KEYLEN(sav->key_enc); 182 if (txform->minkey > keylen || keylen > txform->maxkey) { 183 DPRINTF(("%s: invalid key length %u, must be in the range " 184 "[%u..%u] for algorithm %s\n", __func__, 185 keylen, txform->minkey, txform->maxkey, 186 txform->name)); 187 return EINVAL; 188 } 189 190 /* 191 * NB: The null xform needs a non-zero blocksize to keep the 192 * crypto code happy but if we use it to set ivlen then 193 * the ESP header will be processed incorrectly. The 194 * compromise is to force it to zero here. 195 */ 196 sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize); 197 sav->iv = (caddr_t) malloc(sav->ivlen, M_XDATA, M_WAITOK); 198 if (sav->iv == NULL) { 199 DPRINTF(("%s: no memory for IV\n", __func__)); 200 return EINVAL; 201 } 202 key_randomfill(sav->iv, sav->ivlen); /*XXX*/ 203 204 /* 205 * Setup AH-related state. 206 */ 207 if (sav->alg_auth != 0) { 208 error = ah_init0(sav, xsp, &cria); 209 if (error) 210 return error; 211 } 212 213 /* NB: override anything set in ah_init0 */ 214 sav->tdb_xform = xsp; 215 sav->tdb_encalgxform = txform; 216 217 /* Initialize crypto session. */ 218 bzero(&crie, sizeof (crie)); 219 crie.cri_alg = sav->tdb_encalgxform->type; 220 crie.cri_klen = _KEYBITS(sav->key_enc); 221 crie.cri_key = sav->key_enc->key_data; 222 /* XXX Rounds ? */ 223 224 if (sav->tdb_authalgxform && sav->tdb_encalgxform) { 225 /* init both auth & enc */ 226 crie.cri_next = &cria; 227 error = crypto_newsession(&sav->tdb_cryptoid, 228 &crie, V_crypto_support); 229 } else if (sav->tdb_encalgxform) { 230 error = crypto_newsession(&sav->tdb_cryptoid, 231 &crie, V_crypto_support); 232 } else if (sav->tdb_authalgxform) { 233 error = crypto_newsession(&sav->tdb_cryptoid, 234 &cria, V_crypto_support); 235 } else { 236 /* XXX cannot happen? */ 237 DPRINTF(("%s: no encoding OR authentication xform!\n", 238 __func__)); 239 error = EINVAL; 240 } 241 return error; 242 } 243 244 /* 245 * Paranoia. 246 */ 247 static int 248 esp_zeroize(struct secasvar *sav) 249 { 250 /* NB: ah_zerorize free's the crypto session state */ 251 int error = ah_zeroize(sav); 252 253 if (sav->key_enc) 254 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc)); 255 if (sav->iv) { 256 free(sav->iv, M_XDATA); 257 sav->iv = NULL; 258 } 259 sav->tdb_encalgxform = NULL; 260 sav->tdb_xform = NULL; 261 return error; 262 } 263 264 /* 265 * ESP input processing, called (eventually) through the protocol switch. 266 */ 267 static int 268 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 269 { 270 struct auth_hash *esph; 271 struct enc_xform *espx; 272 struct tdb_ident *tdbi; 273 struct tdb_crypto *tc; 274 int plen, alen, hlen; 275 struct m_tag *mtag; 276 struct newesp *esp; 277 278 struct cryptodesc *crde; 279 struct cryptop *crp; 280 281 IPSEC_ASSERT(sav != NULL, ("null SA")); 282 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); 283 IPSEC_ASSERT((skip&3) == 0 && (m->m_pkthdr.len&3) == 0, 284 ("misaligned packet, skip %u pkt len %u", 285 skip, m->m_pkthdr.len)); 286 287 /* XXX don't pullup, just copy header */ 288 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 289 290 esph = sav->tdb_authalgxform; 291 espx = sav->tdb_encalgxform; 292 293 /* Determine the ESP header length */ 294 if (sav->flags & SADB_X_EXT_OLD) 295 hlen = sizeof (struct esp) + sav->ivlen; 296 else 297 hlen = sizeof (struct newesp) + sav->ivlen; 298 /* Authenticator hash size */ 299 alen = esph ? AH_HMAC_HASHLEN : 0; 300 301 /* 302 * Verify payload length is multiple of encryption algorithm 303 * block size. 304 * 305 * NB: This works for the null algorithm because the blocksize 306 * is 4 and all packets must be 4-byte aligned regardless 307 * of the algorithm. 308 */ 309 plen = m->m_pkthdr.len - (skip + hlen + alen); 310 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 311 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 312 " SA %s/%08lx\n", __func__, 313 plen, espx->blocksize, 314 ipsec_address(&sav->sah->saidx.dst), 315 (u_long) ntohl(sav->spi))); 316 V_espstat.esps_badilen++; 317 m_freem(m); 318 return EINVAL; 319 } 320 321 /* 322 * Check sequence number. 323 */ 324 if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) { 325 DPRINTF(("%s: packet replay check for %s\n", __func__, 326 ipsec_logsastr(sav))); /*XXX*/ 327 V_espstat.esps_replay++; 328 m_freem(m); 329 return ENOBUFS; /*XXX*/ 330 } 331 332 /* Update the counters */ 333 V_espstat.esps_ibytes += m->m_pkthdr.len - (skip + hlen + alen); 334 335 /* Find out if we've already done crypto */ 336 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL); 337 mtag != NULL; 338 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) { 339 tdbi = (struct tdb_ident *) (mtag + 1); 340 if (tdbi->proto == sav->sah->saidx.proto && 341 tdbi->spi == sav->spi && 342 !bcmp(&tdbi->dst, &sav->sah->saidx.dst, 343 sizeof(union sockaddr_union))) 344 break; 345 } 346 347 /* Get crypto descriptors */ 348 crp = crypto_getreq(esph && espx ? 2 : 1); 349 if (crp == NULL) { 350 DPRINTF(("%s: failed to acquire crypto descriptors\n", 351 __func__)); 352 V_espstat.esps_crypto++; 353 m_freem(m); 354 return ENOBUFS; 355 } 356 357 /* Get IPsec-specific opaque pointer */ 358 if (esph == NULL || mtag != NULL) 359 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 360 M_XDATA, M_NOWAIT|M_ZERO); 361 else 362 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen, 363 M_XDATA, M_NOWAIT|M_ZERO); 364 if (tc == NULL) { 365 crypto_freereq(crp); 366 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 367 V_espstat.esps_crypto++; 368 m_freem(m); 369 return ENOBUFS; 370 } 371 372 tc->tc_ptr = (caddr_t) mtag; 373 374 if (esph) { 375 struct cryptodesc *crda = crp->crp_desc; 376 377 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor")); 378 379 /* Authentication descriptor */ 380 crda->crd_skip = skip; 381 crda->crd_len = m->m_pkthdr.len - (skip + alen); 382 crda->crd_inject = m->m_pkthdr.len - alen; 383 384 crda->crd_alg = esph->type; 385 crda->crd_key = sav->key_auth->key_data; 386 crda->crd_klen = _KEYBITS(sav->key_auth); 387 388 /* Copy the authenticator */ 389 if (mtag == NULL) 390 m_copydata(m, m->m_pkthdr.len - alen, alen, 391 (caddr_t) (tc + 1)); 392 393 /* Chain authentication request */ 394 crde = crda->crd_next; 395 } else { 396 crde = crp->crp_desc; 397 } 398 399 /* Crypto operation descriptor */ 400 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 401 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 402 crp->crp_buf = (caddr_t) m; 403 crp->crp_callback = esp_input_cb; 404 crp->crp_sid = sav->tdb_cryptoid; 405 crp->crp_opaque = (caddr_t) tc; 406 407 /* These are passed as-is to the callback */ 408 tc->tc_spi = sav->spi; 409 tc->tc_dst = sav->sah->saidx.dst; 410 tc->tc_proto = sav->sah->saidx.proto; 411 tc->tc_protoff = protoff; 412 tc->tc_skip = skip; 413 414 /* Decryption descriptor */ 415 if (espx) { 416 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor")); 417 crde->crd_skip = skip + hlen; 418 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 419 crde->crd_inject = skip + hlen - sav->ivlen; 420 421 crde->crd_alg = espx->type; 422 crde->crd_key = sav->key_enc->key_data; 423 crde->crd_klen = _KEYBITS(sav->key_enc); 424 /* XXX Rounds ? */ 425 } 426 427 if (mtag == NULL) 428 return crypto_dispatch(crp); 429 else 430 return esp_input_cb(crp); 431 } 432 433 #ifdef INET6 434 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \ 435 if (saidx->dst.sa.sa_family == AF_INET6) { \ 436 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \ 437 } else { \ 438 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \ 439 } \ 440 } while (0) 441 #else 442 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \ 443 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag)) 444 #endif 445 446 /* 447 * ESP input callback from the crypto driver. 448 */ 449 static int 450 esp_input_cb(struct cryptop *crp) 451 { 452 u_int8_t lastthree[3], aalg[AH_HMAC_HASHLEN]; 453 int hlen, skip, protoff, error; 454 struct mbuf *m; 455 struct cryptodesc *crd; 456 struct auth_hash *esph; 457 struct enc_xform *espx; 458 struct tdb_crypto *tc; 459 struct m_tag *mtag; 460 struct secasvar *sav; 461 struct secasindex *saidx; 462 caddr_t ptr; 463 464 crd = crp->crp_desc; 465 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!")); 466 467 tc = (struct tdb_crypto *) crp->crp_opaque; 468 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!")); 469 skip = tc->tc_skip; 470 protoff = tc->tc_protoff; 471 mtag = (struct m_tag *) tc->tc_ptr; 472 m = (struct mbuf *) crp->crp_buf; 473 474 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 475 if (sav == NULL) { 476 V_espstat.esps_notdb++; 477 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 478 __func__, ipsec_address(&tc->tc_dst), 479 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 480 error = ENOBUFS; /*XXX*/ 481 goto bad; 482 } 483 484 saidx = &sav->sah->saidx; 485 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 486 saidx->dst.sa.sa_family == AF_INET6, 487 ("unexpected protocol family %u", 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 error = crypto_dispatch(crp); 501 return error; 502 } 503 504 V_espstat.esps_noxform++; 505 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 506 error = crp->crp_etype; 507 goto bad; 508 } 509 510 /* Shouldn't happen... */ 511 if (m == NULL) { 512 V_espstat.esps_crypto++; 513 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 514 error = EINVAL; 515 goto bad; 516 } 517 V_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 V_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 - AH_HMAC_HASHLEN, 530 AH_HMAC_HASHLEN, aalg); 531 532 ptr = (caddr_t) (tc + 1); 533 534 /* Verify authenticator */ 535 if (bcmp(ptr, aalg, AH_HMAC_HASHLEN) != 0) { 536 DPRINTF(("%s: " 537 "authentication hash mismatch for packet in SA %s/%08lx\n", 538 __func__, 539 ipsec_address(&saidx->dst), 540 (u_long) ntohl(sav->spi))); 541 V_espstat.esps_badauth++; 542 error = EACCES; 543 goto bad; 544 } 545 } 546 547 /* Remove trailing authenticator */ 548 m_adj(m, -AH_HMAC_HASHLEN); 549 } 550 551 /* Release the crypto descriptors */ 552 free(tc, M_XDATA), tc = NULL; 553 crypto_freereq(crp), crp = NULL; 554 555 /* 556 * Packet is now decrypted. 557 */ 558 m->m_flags |= M_DECRYPTED; 559 560 /* 561 * Update replay sequence number, if appropriate. 562 */ 563 if (sav->replay) { 564 u_int32_t seq; 565 566 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 567 sizeof (seq), (caddr_t) &seq); 568 if (ipsec_updatereplay(ntohl(seq), sav)) { 569 DPRINTF(("%s: packet replay check for %s\n", __func__, 570 ipsec_logsastr(sav))); 571 V_espstat.esps_replay++; 572 error = ENOBUFS; 573 goto bad; 574 } 575 } 576 577 /* Determine the ESP header length */ 578 if (sav->flags & SADB_X_EXT_OLD) 579 hlen = sizeof (struct esp) + sav->ivlen; 580 else 581 hlen = sizeof (struct newesp) + sav->ivlen; 582 583 /* Remove the ESP header and IV from the mbuf. */ 584 error = m_striphdr(m, skip, hlen); 585 if (error) { 586 V_espstat.esps_hdrops++; 587 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 588 ipsec_address(&sav->sah->saidx.dst), 589 (u_long) ntohl(sav->spi))); 590 goto bad; 591 } 592 593 /* Save the last three bytes of decrypted data */ 594 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 595 596 /* Verify pad length */ 597 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 598 V_espstat.esps_badilen++; 599 DPRINTF(("%s: invalid padding length %d for %u byte packet " 600 "in SA %s/%08lx\n", __func__, 601 lastthree[1], m->m_pkthdr.len - skip, 602 ipsec_address(&sav->sah->saidx.dst), 603 (u_long) ntohl(sav->spi))); 604 error = EINVAL; 605 goto bad; 606 } 607 608 /* Verify correct decryption by checking the last padding bytes */ 609 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 610 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 611 V_espstat.esps_badenc++; 612 DPRINTF(("%s: decryption failed for packet in " 613 "SA %s/%08lx\n", __func__, 614 ipsec_address(&sav->sah->saidx.dst), 615 (u_long) ntohl(sav->spi))); 616 error = EINVAL; 617 goto bad; 618 } 619 } 620 621 /* Trim the mbuf chain to remove trailing authenticator and padding */ 622 m_adj(m, -(lastthree[1] + 2)); 623 624 /* Restore the Next Protocol field */ 625 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 626 627 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag); 628 629 KEY_FREESAV(&sav); 630 return error; 631 bad: 632 if (sav) 633 KEY_FREESAV(&sav); 634 if (m != NULL) 635 m_freem(m); 636 if (tc != NULL) 637 free(tc, M_XDATA); 638 if (crp != NULL) 639 crypto_freereq(crp); 640 return error; 641 } 642 643 /* 644 * ESP output routine, called by ipsec[46]_process_packet(). 645 */ 646 static int 647 esp_output( 648 struct mbuf *m, 649 struct ipsecrequest *isr, 650 struct mbuf **mp, 651 int skip, 652 int protoff 653 ) 654 { 655 struct enc_xform *espx; 656 struct auth_hash *esph; 657 int hlen, rlen, plen, padding, blks, alen, i, roff; 658 struct mbuf *mo = (struct mbuf *) NULL; 659 struct tdb_crypto *tc; 660 struct secasvar *sav; 661 struct secasindex *saidx; 662 unsigned char *pad; 663 u_int8_t prot; 664 int error, maxpacketsize; 665 666 struct cryptodesc *crde = NULL, *crda = NULL; 667 struct cryptop *crp; 668 669 sav = isr->sav; 670 IPSEC_ASSERT(sav != NULL, ("null SA")); 671 esph = sav->tdb_authalgxform; 672 espx = sav->tdb_encalgxform; 673 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 674 675 if (sav->flags & SADB_X_EXT_OLD) 676 hlen = sizeof (struct esp) + sav->ivlen; 677 else 678 hlen = sizeof (struct newesp) + sav->ivlen; 679 680 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 681 /* 682 * NB: The null encoding transform has a blocksize of 4 683 * so that headers are properly aligned. 684 */ 685 blks = espx->blocksize; /* IV blocksize */ 686 687 /* XXX clamp padding length a la KAME??? */ 688 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 689 plen = rlen + padding; /* Padded payload length. */ 690 691 if (esph) 692 alen = AH_HMAC_HASHLEN; 693 else 694 alen = 0; 695 696 V_espstat.esps_output++; 697 698 saidx = &sav->sah->saidx; 699 /* Check for maximum packet size violations. */ 700 switch (saidx->dst.sa.sa_family) { 701 #ifdef INET 702 case AF_INET: 703 maxpacketsize = IP_MAXPACKET; 704 break; 705 #endif /* INET */ 706 #ifdef INET6 707 case AF_INET6: 708 maxpacketsize = IPV6_MAXPACKET; 709 break; 710 #endif /* INET6 */ 711 default: 712 DPRINTF(("%s: unknown/unsupported protocol " 713 "family %d, SA %s/%08lx\n", __func__, 714 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst), 715 (u_long) ntohl(sav->spi))); 716 V_espstat.esps_nopf++; 717 error = EPFNOSUPPORT; 718 goto bad; 719 } 720 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 721 DPRINTF(("%s: packet in SA %s/%08lx got too big " 722 "(len %u, max len %u)\n", __func__, 723 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi), 724 skip + hlen + rlen + padding + alen, maxpacketsize)); 725 V_espstat.esps_toobig++; 726 error = EMSGSIZE; 727 goto bad; 728 } 729 730 /* Update the counters. */ 731 V_espstat.esps_obytes += m->m_pkthdr.len - skip; 732 733 m = m_unshare(m, M_NOWAIT); 734 if (m == NULL) { 735 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 736 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 737 V_espstat.esps_hdrops++; 738 error = ENOBUFS; 739 goto bad; 740 } 741 742 /* Inject ESP header. */ 743 mo = m_makespace(m, skip, hlen, &roff); 744 if (mo == NULL) { 745 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 746 __func__, hlen, ipsec_address(&saidx->dst), 747 (u_long) ntohl(sav->spi))); 748 V_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; 757 758 #ifdef REGRESSION 759 /* Emulate replay attack when ipsec_replay is TRUE. */ 760 if (!V_ipsec_replay) 761 #endif 762 sav->replay->count++; 763 replay = htonl(sav->replay->count); 764 bcopy((caddr_t) &replay, 765 mtod(mo, caddr_t) + roff + sizeof(u_int32_t), 766 sizeof(u_int32_t)); 767 } 768 769 /* 770 * Add padding -- better to do it ourselves than use the crypto engine, 771 * although if/when we support compression, we'd have to do that. 772 */ 773 pad = (u_char *) m_pad(m, padding + alen); 774 if (pad == NULL) { 775 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 776 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 777 m = NULL; /* NB: free'd by m_pad */ 778 error = ENOBUFS; 779 goto bad; 780 } 781 782 /* 783 * Add padding: random, zero, or self-describing. 784 * XXX catch unexpected setting 785 */ 786 switch (sav->flags & SADB_X_EXT_PMASK) { 787 case SADB_X_EXT_PRAND: 788 (void) read_random(pad, padding - 2); 789 break; 790 case SADB_X_EXT_PZERO: 791 bzero(pad, padding - 2); 792 break; 793 case SADB_X_EXT_PSEQ: 794 for (i = 0; i < padding - 2; i++) 795 pad[i] = i+1; 796 break; 797 } 798 799 /* Fix padding length and Next Protocol in padding itself. */ 800 pad[padding - 2] = padding - 2; 801 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 802 803 /* Fix Next Protocol in IPv4/IPv6 header. */ 804 prot = IPPROTO_ESP; 805 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 806 807 /* Get crypto descriptors. */ 808 crp = crypto_getreq(esph && espx ? 2 : 1); 809 if (crp == NULL) { 810 DPRINTF(("%s: failed to acquire crypto descriptors\n", 811 __func__)); 812 V_espstat.esps_crypto++; 813 error = ENOBUFS; 814 goto bad; 815 } 816 817 if (espx) { 818 crde = crp->crp_desc; 819 crda = crde->crd_next; 820 821 /* Encryption descriptor. */ 822 crde->crd_skip = skip + hlen; 823 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 824 crde->crd_flags = CRD_F_ENCRYPT; 825 crde->crd_inject = skip + hlen - sav->ivlen; 826 827 /* Encryption operation. */ 828 crde->crd_alg = espx->type; 829 crde->crd_key = sav->key_enc->key_data; 830 crde->crd_klen = _KEYBITS(sav->key_enc); 831 /* XXX Rounds ? */ 832 } else 833 crda = crp->crp_desc; 834 835 /* IPsec-specific opaque crypto info. */ 836 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto), 837 M_XDATA, M_NOWAIT|M_ZERO); 838 if (tc == NULL) { 839 crypto_freereq(crp); 840 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 841 V_espstat.esps_crypto++; 842 error = ENOBUFS; 843 goto bad; 844 } 845 846 /* Callback parameters */ 847 tc->tc_isr = isr; 848 tc->tc_spi = sav->spi; 849 tc->tc_dst = saidx->dst; 850 tc->tc_proto = saidx->proto; 851 852 /* Crypto operation descriptor. */ 853 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 854 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 855 crp->crp_buf = (caddr_t) m; 856 crp->crp_callback = esp_output_cb; 857 crp->crp_opaque = (caddr_t) tc; 858 crp->crp_sid = sav->tdb_cryptoid; 859 860 if (esph) { 861 /* Authentication descriptor. */ 862 crda->crd_skip = skip; 863 crda->crd_len = m->m_pkthdr.len - (skip + alen); 864 crda->crd_inject = m->m_pkthdr.len - alen; 865 866 /* Authentication operation. */ 867 crda->crd_alg = esph->type; 868 crda->crd_key = sav->key_auth->key_data; 869 crda->crd_klen = _KEYBITS(sav->key_auth); 870 } 871 872 return crypto_dispatch(crp); 873 bad: 874 if (m) 875 m_freem(m); 876 return (error); 877 } 878 879 /* 880 * ESP output callback from the crypto driver. 881 */ 882 static int 883 esp_output_cb(struct cryptop *crp) 884 { 885 struct tdb_crypto *tc; 886 struct ipsecrequest *isr; 887 struct secasvar *sav; 888 struct mbuf *m; 889 int err, error; 890 891 tc = (struct tdb_crypto *) crp->crp_opaque; 892 IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); 893 m = (struct mbuf *) crp->crp_buf; 894 895 isr = tc->tc_isr; 896 IPSECREQUEST_LOCK(isr); 897 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 898 if (sav == NULL) { 899 V_espstat.esps_notdb++; 900 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n", 901 __func__, ipsec_address(&tc->tc_dst), 902 (u_long) ntohl(tc->tc_spi), tc->tc_proto)); 903 error = ENOBUFS; /*XXX*/ 904 goto bad; 905 } 906 IPSEC_ASSERT(isr->sav == sav, 907 ("SA changed was %p now %p\n", isr->sav, sav)); 908 909 /* Check for crypto errors. */ 910 if (crp->crp_etype) { 911 /* Reset session ID. */ 912 if (sav->tdb_cryptoid != 0) 913 sav->tdb_cryptoid = crp->crp_sid; 914 915 if (crp->crp_etype == EAGAIN) { 916 KEY_FREESAV(&sav); 917 IPSECREQUEST_UNLOCK(isr); 918 error = crypto_dispatch(crp); 919 return error; 920 } 921 922 V_espstat.esps_noxform++; 923 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 924 error = crp->crp_etype; 925 goto bad; 926 } 927 928 /* Shouldn't happen... */ 929 if (m == NULL) { 930 V_espstat.esps_crypto++; 931 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 932 error = EINVAL; 933 goto bad; 934 } 935 V_espstat.esps_hist[sav->alg_enc]++; 936 if (sav->tdb_authalgxform != NULL) 937 V_ahstat.ahs_hist[sav->alg_auth]++; 938 939 /* Release crypto descriptors. */ 940 free(tc, M_XDATA); 941 crypto_freereq(crp); 942 943 #ifdef REGRESSION 944 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 945 if (V_ipsec_integrity) { 946 static unsigned char ipseczeroes[AH_HMAC_HASHLEN]; 947 struct auth_hash *esph; 948 949 /* 950 * Corrupt HMAC if we want to test integrity verification of 951 * the other side. 952 */ 953 esph = sav->tdb_authalgxform; 954 if (esph != NULL) { 955 m_copyback(m, m->m_pkthdr.len - AH_HMAC_HASHLEN, 956 AH_HMAC_HASHLEN, ipseczeroes); 957 } 958 } 959 #endif 960 961 /* NB: m is reclaimed by ipsec_process_done. */ 962 err = ipsec_process_done(m, isr); 963 KEY_FREESAV(&sav); 964 IPSECREQUEST_UNLOCK(isr); 965 return err; 966 bad: 967 if (sav) 968 KEY_FREESAV(&sav); 969 IPSECREQUEST_UNLOCK(isr); 970 if (m) 971 m_freem(m); 972 free(tc, M_XDATA); 973 crypto_freereq(crp); 974 return error; 975 } 976 977 static struct xformsw esp_xformsw = { 978 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP", 979 esp_init, esp_zeroize, esp_input, 980 esp_output 981 }; 982 983 static void 984 esp_attach(void) 985 { 986 #define MAXIV(xform) \ 987 if (xform.blocksize > V_esp_max_ivlen) \ 988 V_esp_max_ivlen = xform.blocksize \ 989 990 V_esp_max_ivlen = 0; 991 MAXIV(enc_xform_des); /* SADB_EALG_DESCBC */ 992 MAXIV(enc_xform_3des); /* SADB_EALG_3DESCBC */ 993 MAXIV(enc_xform_rijndael128); /* SADB_X_EALG_AES */ 994 MAXIV(enc_xform_blf); /* SADB_X_EALG_BLOWFISHCBC */ 995 MAXIV(enc_xform_cast5); /* SADB_X_EALG_CAST128CBC */ 996 MAXIV(enc_xform_skipjack); /* SADB_X_EALG_SKIPJACK */ 997 MAXIV(enc_xform_null); /* SADB_EALG_NULL */ 998 MAXIV(enc_xform_camellia); /* SADB_X_EALG_CAMELLIACBC */ 999 1000 xform_register(&esp_xformsw); 1001 #undef MAXIV 1002 } 1003 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL); 1004