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/lock.h> 48 #include <sys/random.h> 49 #include <sys/mutex.h> 50 #include <sys/sysctl.h> 51 #include <sys/mutex.h> 52 #include <machine/atomic.h> 53 54 #include <net/if.h> 55 #include <net/vnet.h> 56 57 #include <netinet/in.h> 58 #include <netinet/in_systm.h> 59 #include <netinet/ip.h> 60 #include <netinet/ip_ecn.h> 61 #include <netinet/ip6.h> 62 63 #include <netipsec/ipsec.h> 64 #include <netipsec/ah.h> 65 #include <netipsec/ah_var.h> 66 #include <netipsec/esp.h> 67 #include <netipsec/esp_var.h> 68 #include <netipsec/xform.h> 69 70 #ifdef INET6 71 #include <netinet6/ip6_var.h> 72 #include <netipsec/ipsec6.h> 73 #include <netinet6/ip6_ecn.h> 74 #endif 75 76 #include <netipsec/key.h> 77 #include <netipsec/key_debug.h> 78 79 #include <opencrypto/cryptodev.h> 80 #include <opencrypto/xform.h> 81 82 VNET_DEFINE(int, esp_enable) = 1; 83 VNET_PCPUSTAT_DEFINE(struct espstat, espstat); 84 VNET_PCPUSTAT_SYSINIT(espstat); 85 86 #ifdef VIMAGE 87 VNET_PCPUSTAT_SYSUNINIT(espstat); 88 #endif /* VIMAGE */ 89 90 SYSCTL_DECL(_net_inet_esp); 91 SYSCTL_INT(_net_inet_esp, OID_AUTO, esp_enable, 92 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(esp_enable), 0, ""); 93 SYSCTL_VNET_PCPUSTAT(_net_inet_esp, IPSECCTL_STATS, stats, 94 struct espstat, espstat, 95 "ESP statistics (struct espstat, netipsec/esp_var.h"); 96 97 static int esp_input_cb(struct cryptop *op); 98 static int esp_output_cb(struct cryptop *crp); 99 100 size_t 101 esp_hdrsiz(struct secasvar *sav) 102 { 103 size_t size; 104 105 if (sav != NULL) { 106 /*XXX not right for null algorithm--does it matter??*/ 107 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 108 ("SA with null xform")); 109 if (sav->flags & SADB_X_EXT_OLD) 110 size = sizeof (struct esp); 111 else 112 size = sizeof (struct newesp); 113 size += sav->tdb_encalgxform->blocksize + 9; 114 /*XXX need alg check???*/ 115 if (sav->tdb_authalgxform != NULL && sav->replay) 116 size += ah_hdrsiz(sav); 117 } else { 118 /* 119 * base header size 120 * + max iv length for CBC mode 121 * + max pad length 122 * + sizeof (pad length field) 123 * + sizeof (next header field) 124 * + max icv supported. 125 */ 126 size = sizeof (struct newesp) + EALG_MAX_BLOCK_LEN + 9 + 16; 127 } 128 return size; 129 } 130 131 /* 132 * esp_init() is called when an SPI is being set up. 133 */ 134 static int 135 esp_init(struct secasvar *sav, struct xformsw *xsp) 136 { 137 const struct enc_xform *txform; 138 struct cryptoini cria, crie; 139 int keylen; 140 int error; 141 142 txform = enc_algorithm_lookup(sav->alg_enc); 143 if (txform == NULL) { 144 DPRINTF(("%s: unsupported encryption algorithm %d\n", 145 __func__, sav->alg_enc)); 146 return EINVAL; 147 } 148 if (sav->key_enc == NULL) { 149 DPRINTF(("%s: no encoding key for %s algorithm\n", 150 __func__, txform->name)); 151 return EINVAL; 152 } 153 if ((sav->flags & (SADB_X_EXT_OLD | SADB_X_EXT_IV4B)) == 154 SADB_X_EXT_IV4B) { 155 DPRINTF(("%s: 4-byte IV not supported with protocol\n", 156 __func__)); 157 return EINVAL; 158 } 159 /* subtract off the salt, RFC4106, 8.1 and RFC3686, 5.1 */ 160 keylen = _KEYLEN(sav->key_enc) - SAV_ISCTRORGCM(sav) * 4; 161 if (txform->minkey > keylen || keylen > txform->maxkey) { 162 DPRINTF(("%s: invalid key length %u, must be in the range " 163 "[%u..%u] for algorithm %s\n", __func__, 164 keylen, txform->minkey, txform->maxkey, 165 txform->name)); 166 return EINVAL; 167 } 168 169 if (SAV_ISCTRORGCM(sav)) 170 sav->ivlen = 8; /* RFC4106 3.1 and RFC3686 3.1 */ 171 else 172 sav->ivlen = txform->ivsize; 173 174 /* 175 * Setup AH-related state. 176 */ 177 if (sav->alg_auth != 0) { 178 error = ah_init0(sav, xsp, &cria); 179 if (error) 180 return error; 181 } 182 183 /* NB: override anything set in ah_init0 */ 184 sav->tdb_xform = xsp; 185 sav->tdb_encalgxform = txform; 186 187 /* 188 * Whenever AES-GCM is used for encryption, one 189 * of the AES authentication algorithms is chosen 190 * as well, based on the key size. 191 */ 192 if (sav->alg_enc == SADB_X_EALG_AESGCM16) { 193 switch (keylen) { 194 case AES_128_GMAC_KEY_LEN: 195 sav->alg_auth = SADB_X_AALG_AES128GMAC; 196 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_128; 197 break; 198 case AES_192_GMAC_KEY_LEN: 199 sav->alg_auth = SADB_X_AALG_AES192GMAC; 200 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_192; 201 break; 202 case AES_256_GMAC_KEY_LEN: 203 sav->alg_auth = SADB_X_AALG_AES256GMAC; 204 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_256; 205 break; 206 default: 207 DPRINTF(("%s: invalid key length %u" 208 "for algorithm %s\n", __func__, 209 keylen, txform->name)); 210 return EINVAL; 211 } 212 bzero(&cria, sizeof(cria)); 213 cria.cri_alg = sav->tdb_authalgxform->type; 214 cria.cri_key = sav->key_enc->key_data; 215 cria.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISGCM(sav) * 32; 216 } 217 218 /* Initialize crypto session. */ 219 bzero(&crie, sizeof(crie)); 220 crie.cri_alg = sav->tdb_encalgxform->type; 221 crie.cri_key = sav->key_enc->key_data; 222 crie.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISCTRORGCM(sav) * 32; 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 sav->tdb_encalgxform = NULL; 256 sav->tdb_xform = NULL; 257 return error; 258 } 259 260 /* 261 * ESP input processing, called (eventually) through the protocol switch. 262 */ 263 static int 264 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 265 { 266 char buf[128]; 267 const struct auth_hash *esph; 268 const struct enc_xform *espx; 269 struct xform_data *xd; 270 struct cryptodesc *crde; 271 struct cryptop *crp; 272 struct newesp *esp; 273 uint8_t *ivp; 274 uint64_t cryptoid; 275 int plen, alen, hlen; 276 277 IPSEC_ASSERT(sav != NULL, ("null SA")); 278 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); 279 280 /* Valid IP Packet length ? */ 281 if ( (skip&3) || (m->m_pkthdr.len&3) ){ 282 DPRINTF(("%s: misaligned packet, skip %u pkt len %u", 283 __func__, skip, m->m_pkthdr.len)); 284 ESPSTAT_INC(esps_badilen); 285 m_freem(m); 286 return EINVAL; 287 } 288 /* XXX don't pullup, just copy header */ 289 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp)); 290 291 esph = sav->tdb_authalgxform; 292 espx = sav->tdb_encalgxform; 293 294 /* Determine the ESP header and auth length */ 295 if (sav->flags & SADB_X_EXT_OLD) 296 hlen = sizeof (struct esp) + sav->ivlen; 297 else 298 hlen = sizeof (struct newesp) + sav->ivlen; 299 300 alen = xform_ah_authsize(esph); 301 302 /* 303 * Verify payload length is multiple of encryption algorithm 304 * block size. 305 * 306 * NB: This works for the null algorithm because the blocksize 307 * is 4 and all packets must be 4-byte aligned regardless 308 * of the algorithm. 309 */ 310 plen = m->m_pkthdr.len - (skip + hlen + alen); 311 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 312 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 313 " SA %s/%08lx\n", __func__, plen, espx->blocksize, 314 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 315 (u_long)ntohl(sav->spi))); 316 ESPSTAT_INC(esps_badilen); 317 m_freem(m); 318 return EINVAL; 319 } 320 321 /* 322 * Check sequence number. 323 */ 324 SECASVAR_LOCK(sav); 325 if (esph != NULL && sav->replay != NULL && sav->replay->wsize != 0) { 326 if (ipsec_chkreplay(ntohl(esp->esp_seq), sav) == 0) { 327 SECASVAR_UNLOCK(sav); 328 DPRINTF(("%s: packet replay check for %s\n", __func__, 329 ipsec_sa2str(sav, buf, sizeof(buf)))); 330 ESPSTAT_INC(esps_replay); 331 m_freem(m); 332 return (EACCES); 333 } 334 } 335 cryptoid = sav->tdb_cryptoid; 336 SECASVAR_UNLOCK(sav); 337 338 /* Update the counters */ 339 ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen)); 340 341 /* Get crypto descriptors */ 342 crp = crypto_getreq(esph && espx ? 2 : 1); 343 if (crp == NULL) { 344 DPRINTF(("%s: failed to acquire crypto descriptors\n", 345 __func__)); 346 ESPSTAT_INC(esps_crypto); 347 m_freem(m); 348 return ENOBUFS; 349 } 350 351 /* Get IPsec-specific opaque pointer */ 352 xd = malloc(sizeof(*xd) + alen, M_XDATA, M_NOWAIT | M_ZERO); 353 if (xd == NULL) { 354 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 355 ESPSTAT_INC(esps_crypto); 356 crypto_freereq(crp); 357 m_freem(m); 358 return ENOBUFS; 359 } 360 361 if (esph != NULL) { 362 struct cryptodesc *crda = crp->crp_desc; 363 364 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor")); 365 366 /* Authentication descriptor */ 367 crda->crd_skip = skip; 368 if (SAV_ISGCM(sav)) 369 crda->crd_len = 8; /* RFC4106 5, SPI + SN */ 370 else 371 crda->crd_len = m->m_pkthdr.len - (skip + alen); 372 crda->crd_inject = m->m_pkthdr.len - alen; 373 374 crda->crd_alg = esph->type; 375 376 /* Copy the authenticator */ 377 m_copydata(m, m->m_pkthdr.len - alen, alen, 378 (caddr_t) (xd + 1)); 379 380 /* Chain authentication request */ 381 crde = crda->crd_next; 382 } else { 383 crde = crp->crp_desc; 384 } 385 386 /* Crypto operation descriptor */ 387 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 388 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 389 crp->crp_buf = (caddr_t) m; 390 crp->crp_callback = esp_input_cb; 391 crp->crp_sid = cryptoid; 392 crp->crp_opaque = (caddr_t) xd; 393 394 /* These are passed as-is to the callback */ 395 xd->sav = sav; 396 xd->protoff = protoff; 397 xd->skip = skip; 398 xd->cryptoid = cryptoid; 399 400 /* Decryption descriptor */ 401 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor")); 402 crde->crd_skip = skip + hlen; 403 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 404 crde->crd_inject = skip + hlen - sav->ivlen; 405 406 if (SAV_ISCTRORGCM(sav)) { 407 ivp = &crde->crd_iv[0]; 408 409 /* GCM IV Format: RFC4106 4 */ 410 /* CTR IV Format: RFC3686 4 */ 411 /* Salt is last four bytes of key, RFC4106 8.1 */ 412 /* Nonce is last four bytes of key, RFC3686 5.1 */ 413 memcpy(ivp, sav->key_enc->key_data + 414 _KEYLEN(sav->key_enc) - 4, 4); 415 416 if (SAV_ISCTR(sav)) { 417 /* Initial block counter is 1, RFC3686 4 */ 418 be32enc(&ivp[sav->ivlen + 4], 1); 419 } 420 421 m_copydata(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); 422 crde->crd_flags |= CRD_F_IV_EXPLICIT; 423 } 424 425 crde->crd_alg = espx->type; 426 427 return (crypto_dispatch(crp)); 428 } 429 430 /* 431 * ESP input callback from the crypto driver. 432 */ 433 static int 434 esp_input_cb(struct cryptop *crp) 435 { 436 char buf[128]; 437 u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN]; 438 const struct auth_hash *esph; 439 const struct enc_xform *espx; 440 struct mbuf *m; 441 struct cryptodesc *crd; 442 struct xform_data *xd; 443 struct secasvar *sav; 444 struct secasindex *saidx; 445 caddr_t ptr; 446 uint64_t cryptoid; 447 int hlen, skip, protoff, error, alen; 448 449 crd = crp->crp_desc; 450 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!")); 451 452 m = (struct mbuf *) crp->crp_buf; 453 xd = (struct xform_data *) crp->crp_opaque; 454 sav = xd->sav; 455 skip = xd->skip; 456 protoff = xd->protoff; 457 cryptoid = xd->cryptoid; 458 saidx = &sav->sah->saidx; 459 esph = sav->tdb_authalgxform; 460 espx = sav->tdb_encalgxform; 461 462 /* Check for crypto errors */ 463 if (crp->crp_etype) { 464 if (crp->crp_etype == EAGAIN) { 465 /* Reset the session ID */ 466 if (ipsec_updateid(sav, &crp->crp_sid, &cryptoid) != 0) 467 crypto_freesession(cryptoid); 468 xd->cryptoid = crp->crp_sid; 469 return (crypto_dispatch(crp)); 470 } 471 ESPSTAT_INC(esps_noxform); 472 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 473 error = crp->crp_etype; 474 goto bad; 475 } 476 477 /* Shouldn't happen... */ 478 if (m == NULL) { 479 ESPSTAT_INC(esps_crypto); 480 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 481 error = EINVAL; 482 goto bad; 483 } 484 ESPSTAT_INC(esps_hist[sav->alg_enc]); 485 486 /* If authentication was performed, check now. */ 487 if (esph != NULL) { 488 alen = xform_ah_authsize(esph); 489 AHSTAT_INC(ahs_hist[sav->alg_auth]); 490 /* Copy the authenticator from the packet */ 491 m_copydata(m, m->m_pkthdr.len - alen, alen, aalg); 492 ptr = (caddr_t) (xd + 1); 493 494 /* Verify authenticator */ 495 if (timingsafe_bcmp(ptr, aalg, alen) != 0) { 496 DPRINTF(("%s: authentication hash mismatch for " 497 "packet in SA %s/%08lx\n", __func__, 498 ipsec_address(&saidx->dst, buf, sizeof(buf)), 499 (u_long) ntohl(sav->spi))); 500 ESPSTAT_INC(esps_badauth); 501 error = EACCES; 502 goto bad; 503 } 504 m->m_flags |= M_AUTHIPDGM; 505 /* Remove trailing authenticator */ 506 m_adj(m, -alen); 507 } 508 509 /* Release the crypto descriptors */ 510 free(xd, M_XDATA), xd = NULL; 511 crypto_freereq(crp), crp = NULL; 512 513 /* 514 * Packet is now decrypted. 515 */ 516 m->m_flags |= M_DECRYPTED; 517 518 /* 519 * Update replay sequence number, if appropriate. 520 */ 521 if (sav->replay) { 522 u_int32_t seq; 523 524 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 525 sizeof (seq), (caddr_t) &seq); 526 SECASVAR_LOCK(sav); 527 if (ipsec_updatereplay(ntohl(seq), sav)) { 528 SECASVAR_UNLOCK(sav); 529 DPRINTF(("%s: packet replay check for %s\n", __func__, 530 ipsec_sa2str(sav, buf, sizeof(buf)))); 531 ESPSTAT_INC(esps_replay); 532 error = EACCES; 533 goto bad; 534 } 535 SECASVAR_UNLOCK(sav); 536 } 537 538 /* Determine the ESP header length */ 539 if (sav->flags & SADB_X_EXT_OLD) 540 hlen = sizeof (struct esp) + sav->ivlen; 541 else 542 hlen = sizeof (struct newesp) + sav->ivlen; 543 544 /* Remove the ESP header and IV from the mbuf. */ 545 error = m_striphdr(m, skip, hlen); 546 if (error) { 547 ESPSTAT_INC(esps_hdrops); 548 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 549 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 550 (u_long) ntohl(sav->spi))); 551 goto bad; 552 } 553 554 /* Save the last three bytes of decrypted data */ 555 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 556 557 /* Verify pad length */ 558 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 559 ESPSTAT_INC(esps_badilen); 560 DPRINTF(("%s: invalid padding length %d for %u byte packet " 561 "in SA %s/%08lx\n", __func__, lastthree[1], 562 m->m_pkthdr.len - skip, 563 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 564 (u_long) ntohl(sav->spi))); 565 error = EINVAL; 566 goto bad; 567 } 568 569 /* Verify correct decryption by checking the last padding bytes */ 570 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 571 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 572 ESPSTAT_INC(esps_badenc); 573 DPRINTF(("%s: decryption failed for packet in " 574 "SA %s/%08lx\n", __func__, ipsec_address( 575 &sav->sah->saidx.dst, buf, sizeof(buf)), 576 (u_long) ntohl(sav->spi))); 577 error = EINVAL; 578 goto bad; 579 } 580 } 581 582 /* Trim the mbuf chain to remove trailing authenticator and padding */ 583 m_adj(m, -(lastthree[1] + 2)); 584 585 /* Restore the Next Protocol field */ 586 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 587 588 switch (saidx->dst.sa.sa_family) { 589 #ifdef INET6 590 case AF_INET6: 591 error = ipsec6_common_input_cb(m, sav, skip, protoff); 592 break; 593 #endif 594 #ifdef INET 595 case AF_INET: 596 error = ipsec4_common_input_cb(m, sav, skip, protoff); 597 break; 598 #endif 599 default: 600 panic("%s: Unexpected address family: %d saidx=%p", __func__, 601 saidx->dst.sa.sa_family, saidx); 602 } 603 return error; 604 bad: 605 if (sav != NULL) 606 key_freesav(&sav); 607 if (m != NULL) 608 m_freem(m); 609 if (xd != NULL) 610 free(xd, M_XDATA); 611 if (crp != NULL) 612 crypto_freereq(crp); 613 return error; 614 } 615 /* 616 * ESP output routine, called by ipsec[46]_perform_request(). 617 */ 618 static int 619 esp_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav, 620 u_int idx, int skip, int protoff) 621 { 622 char buf[IPSEC_ADDRSTRLEN]; 623 struct cryptodesc *crde = NULL, *crda = NULL; 624 struct cryptop *crp; 625 const struct auth_hash *esph; 626 const struct enc_xform *espx; 627 struct mbuf *mo = NULL; 628 struct xform_data *xd; 629 struct secasindex *saidx; 630 unsigned char *pad; 631 uint8_t *ivp; 632 uint64_t cntr, cryptoid; 633 int hlen, rlen, padding, blks, alen, i, roff; 634 int error, maxpacketsize; 635 uint8_t prot; 636 637 IPSEC_ASSERT(sav != NULL, ("null SA")); 638 esph = sav->tdb_authalgxform; 639 espx = sav->tdb_encalgxform; 640 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 641 642 if (sav->flags & SADB_X_EXT_OLD) 643 hlen = sizeof (struct esp) + sav->ivlen; 644 else 645 hlen = sizeof (struct newesp) + sav->ivlen; 646 647 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 648 /* 649 * RFC4303 2.4 Requires 4 byte alignment. 650 */ 651 blks = MAX(4, espx->blocksize); /* Cipher blocksize */ 652 653 /* XXX clamp padding length a la KAME??? */ 654 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 655 656 alen = xform_ah_authsize(esph); 657 658 ESPSTAT_INC(esps_output); 659 660 saidx = &sav->sah->saidx; 661 /* Check for maximum packet size violations. */ 662 switch (saidx->dst.sa.sa_family) { 663 #ifdef INET 664 case AF_INET: 665 maxpacketsize = IP_MAXPACKET; 666 break; 667 #endif /* INET */ 668 #ifdef INET6 669 case AF_INET6: 670 maxpacketsize = IPV6_MAXPACKET; 671 break; 672 #endif /* INET6 */ 673 default: 674 DPRINTF(("%s: unknown/unsupported protocol " 675 "family %d, SA %s/%08lx\n", __func__, 676 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst, 677 buf, sizeof(buf)), (u_long) ntohl(sav->spi))); 678 ESPSTAT_INC(esps_nopf); 679 error = EPFNOSUPPORT; 680 goto bad; 681 } 682 /* 683 DPRINTF(("%s: skip %d hlen %d rlen %d padding %d alen %d blksd %d\n", 684 __func__, skip, hlen, rlen, padding, alen, blks)); */ 685 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 686 DPRINTF(("%s: packet in SA %s/%08lx got too big " 687 "(len %u, max len %u)\n", __func__, 688 ipsec_address(&saidx->dst, buf, sizeof(buf)), 689 (u_long) ntohl(sav->spi), 690 skip + hlen + rlen + padding + alen, maxpacketsize)); 691 ESPSTAT_INC(esps_toobig); 692 error = EMSGSIZE; 693 goto bad; 694 } 695 696 /* Update the counters. */ 697 ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip); 698 699 m = m_unshare(m, M_NOWAIT); 700 if (m == NULL) { 701 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 702 ipsec_address(&saidx->dst, buf, sizeof(buf)), 703 (u_long) ntohl(sav->spi))); 704 ESPSTAT_INC(esps_hdrops); 705 error = ENOBUFS; 706 goto bad; 707 } 708 709 /* Inject ESP header. */ 710 mo = m_makespace(m, skip, hlen, &roff); 711 if (mo == NULL) { 712 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 713 __func__, hlen, ipsec_address(&saidx->dst, buf, 714 sizeof(buf)), (u_long) ntohl(sav->spi))); 715 ESPSTAT_INC(esps_hdrops); /* XXX diffs from openbsd */ 716 error = ENOBUFS; 717 goto bad; 718 } 719 720 /* Initialize ESP header. */ 721 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, 722 sizeof(uint32_t)); 723 SECASVAR_LOCK(sav); 724 if (sav->replay) { 725 uint32_t replay; 726 727 #ifdef REGRESSION 728 /* Emulate replay attack when ipsec_replay is TRUE. */ 729 if (!V_ipsec_replay) 730 #endif 731 sav->replay->count++; 732 replay = htonl(sav->replay->count); 733 734 bcopy((caddr_t) &replay, mtod(mo, caddr_t) + roff + 735 sizeof(uint32_t), sizeof(uint32_t)); 736 } 737 cryptoid = sav->tdb_cryptoid; 738 if (SAV_ISCTRORGCM(sav)) 739 cntr = sav->cntr++; 740 SECASVAR_UNLOCK(sav); 741 742 /* 743 * Add padding -- better to do it ourselves than use the crypto engine, 744 * although if/when we support compression, we'd have to do that. 745 */ 746 pad = (u_char *) m_pad(m, padding + alen); 747 if (pad == NULL) { 748 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 749 ipsec_address(&saidx->dst, buf, sizeof(buf)), 750 (u_long) ntohl(sav->spi))); 751 m = NULL; /* NB: free'd by m_pad */ 752 error = ENOBUFS; 753 goto bad; 754 } 755 756 /* 757 * Add padding: random, zero, or self-describing. 758 * XXX catch unexpected setting 759 */ 760 switch (sav->flags & SADB_X_EXT_PMASK) { 761 case SADB_X_EXT_PRAND: 762 (void) read_random(pad, padding - 2); 763 break; 764 case SADB_X_EXT_PZERO: 765 bzero(pad, padding - 2); 766 break; 767 case SADB_X_EXT_PSEQ: 768 for (i = 0; i < padding - 2; i++) 769 pad[i] = i+1; 770 break; 771 } 772 773 /* Fix padding length and Next Protocol in padding itself. */ 774 pad[padding - 2] = padding - 2; 775 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 776 777 /* Fix Next Protocol in IPv4/IPv6 header. */ 778 prot = IPPROTO_ESP; 779 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 780 781 /* Get crypto descriptors. */ 782 crp = crypto_getreq(esph != NULL ? 2 : 1); 783 if (crp == NULL) { 784 DPRINTF(("%s: failed to acquire crypto descriptors\n", 785 __func__)); 786 ESPSTAT_INC(esps_crypto); 787 error = ENOBUFS; 788 goto bad; 789 } 790 791 /* IPsec-specific opaque crypto info. */ 792 xd = malloc(sizeof(struct xform_data), M_XDATA, M_NOWAIT | M_ZERO); 793 if (xd == NULL) { 794 crypto_freereq(crp); 795 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 796 ESPSTAT_INC(esps_crypto); 797 error = ENOBUFS; 798 goto bad; 799 } 800 801 crde = crp->crp_desc; 802 crda = crde->crd_next; 803 804 /* Encryption descriptor. */ 805 crde->crd_skip = skip + hlen; 806 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 807 crde->crd_flags = CRD_F_ENCRYPT; 808 crde->crd_inject = skip + hlen - sav->ivlen; 809 810 /* Encryption operation. */ 811 crde->crd_alg = espx->type; 812 if (SAV_ISCTRORGCM(sav)) { 813 ivp = &crde->crd_iv[0]; 814 815 /* GCM IV Format: RFC4106 4 */ 816 /* CTR IV Format: RFC3686 4 */ 817 /* Salt is last four bytes of key, RFC4106 8.1 */ 818 /* Nonce is last four bytes of key, RFC3686 5.1 */ 819 memcpy(ivp, sav->key_enc->key_data + 820 _KEYLEN(sav->key_enc) - 4, 4); 821 be64enc(&ivp[4], cntr); 822 if (SAV_ISCTR(sav)) { 823 /* Initial block counter is 1, RFC3686 4 */ 824 /* XXXAE: should we use this only for first packet? */ 825 be32enc(&ivp[sav->ivlen + 4], 1); 826 } 827 828 m_copyback(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); 829 crde->crd_flags |= CRD_F_IV_EXPLICIT|CRD_F_IV_PRESENT; 830 } 831 832 /* Callback parameters */ 833 xd->sp = sp; 834 xd->sav = sav; 835 xd->idx = idx; 836 xd->cryptoid = cryptoid; 837 838 /* Crypto operation descriptor. */ 839 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 840 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 841 crp->crp_buf = (caddr_t) m; 842 crp->crp_callback = esp_output_cb; 843 crp->crp_opaque = (caddr_t) xd; 844 crp->crp_sid = cryptoid; 845 846 if (esph) { 847 /* Authentication descriptor. */ 848 crda->crd_alg = esph->type; 849 crda->crd_skip = skip; 850 if (SAV_ISGCM(sav)) 851 crda->crd_len = 8; /* RFC4106 5, SPI + SN */ 852 else 853 crda->crd_len = m->m_pkthdr.len - (skip + alen); 854 crda->crd_inject = m->m_pkthdr.len - alen; 855 } 856 857 return crypto_dispatch(crp); 858 bad: 859 if (m) 860 m_freem(m); 861 return (error); 862 } 863 /* 864 * ESP output callback from the crypto driver. 865 */ 866 static int 867 esp_output_cb(struct cryptop *crp) 868 { 869 struct xform_data *xd; 870 struct secpolicy *sp; 871 struct secasvar *sav; 872 struct mbuf *m; 873 uint64_t cryptoid; 874 u_int idx; 875 int error; 876 877 xd = (struct xform_data *) crp->crp_opaque; 878 m = (struct mbuf *) crp->crp_buf; 879 sp = xd->sp; 880 sav = xd->sav; 881 idx = xd->idx; 882 cryptoid = xd->cryptoid; 883 884 /* Check for crypto errors. */ 885 if (crp->crp_etype) { 886 if (crp->crp_etype == EAGAIN) { 887 /* Reset the session ID */ 888 if (ipsec_updateid(sav, &crp->crp_sid, &cryptoid) != 0) 889 crypto_freesession(cryptoid); 890 xd->cryptoid = crp->crp_sid; 891 return (crypto_dispatch(crp)); 892 } 893 ESPSTAT_INC(esps_noxform); 894 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 895 error = crp->crp_etype; 896 m_freem(m); 897 goto bad; 898 } 899 900 /* Shouldn't happen... */ 901 if (m == NULL) { 902 ESPSTAT_INC(esps_crypto); 903 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 904 error = EINVAL; 905 goto bad; 906 } 907 free(xd, M_XDATA); 908 crypto_freereq(crp); 909 ESPSTAT_INC(esps_hist[sav->alg_enc]); 910 if (sav->tdb_authalgxform != NULL) 911 AHSTAT_INC(ahs_hist[sav->alg_auth]); 912 913 #ifdef REGRESSION 914 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 915 if (V_ipsec_integrity) { 916 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN]; 917 const struct auth_hash *esph; 918 919 /* 920 * Corrupt HMAC if we want to test integrity verification of 921 * the other side. 922 */ 923 esph = sav->tdb_authalgxform; 924 if (esph != NULL) { 925 int alen; 926 927 alen = xform_ah_authsize(esph); 928 m_copyback(m, m->m_pkthdr.len - alen, 929 alen, ipseczeroes); 930 } 931 } 932 #endif 933 934 /* NB: m is reclaimed by ipsec_process_done. */ 935 error = ipsec_process_done(m, sp, sav, idx); 936 return (error); 937 bad: 938 free(xd, M_XDATA); 939 crypto_freereq(crp); 940 key_freesav(&sav); 941 key_freesp(&sp); 942 return (error); 943 } 944 945 static struct xformsw esp_xformsw = { 946 .xf_type = XF_ESP, 947 .xf_name = "IPsec ESP", 948 .xf_init = esp_init, 949 .xf_zeroize = esp_zeroize, 950 .xf_input = esp_input, 951 .xf_output = esp_output, 952 }; 953 954 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 955 xform_attach, &esp_xformsw); 956 SYSUNINIT(esp_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 957 xform_detach, &esp_xformsw); 958