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 struct timeval deswarn, blfwarn, castwarn, camelliawarn; 98 99 static int esp_input_cb(struct cryptop *op); 100 static int esp_output_cb(struct cryptop *crp); 101 102 size_t 103 esp_hdrsiz(struct secasvar *sav) 104 { 105 size_t size; 106 107 if (sav != NULL) { 108 /*XXX not right for null algorithm--does it matter??*/ 109 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 110 ("SA with null xform")); 111 if (sav->flags & SADB_X_EXT_OLD) 112 size = sizeof (struct esp); 113 else 114 size = sizeof (struct newesp); 115 size += sav->tdb_encalgxform->blocksize + 9; 116 /*XXX need alg check???*/ 117 if (sav->tdb_authalgxform != NULL && sav->replay) 118 size += ah_hdrsiz(sav); 119 } else { 120 /* 121 * base header size 122 * + max iv length for CBC mode 123 * + max pad length 124 * + sizeof (pad length field) 125 * + sizeof (next header field) 126 * + max icv supported. 127 */ 128 size = sizeof (struct newesp) + EALG_MAX_BLOCK_LEN + 9 + 16; 129 } 130 return size; 131 } 132 133 /* 134 * esp_init() is called when an SPI is being set up. 135 */ 136 static int 137 esp_init(struct secasvar *sav, struct xformsw *xsp) 138 { 139 const struct enc_xform *txform; 140 struct crypto_session_params csp; 141 int keylen; 142 int error; 143 144 txform = enc_algorithm_lookup(sav->alg_enc); 145 if (txform == NULL) { 146 DPRINTF(("%s: unsupported encryption algorithm %d\n", 147 __func__, sav->alg_enc)); 148 return EINVAL; 149 } 150 if (sav->key_enc == NULL) { 151 DPRINTF(("%s: no encoding key for %s algorithm\n", 152 __func__, txform->name)); 153 return EINVAL; 154 } 155 if ((sav->flags & (SADB_X_EXT_OLD | SADB_X_EXT_IV4B)) == 156 SADB_X_EXT_IV4B) { 157 DPRINTF(("%s: 4-byte IV not supported with protocol\n", 158 __func__)); 159 return EINVAL; 160 } 161 162 switch (sav->alg_enc) { 163 case SADB_EALG_DESCBC: 164 if (ratecheck(&deswarn, &ipsec_warn_interval)) 165 gone_in(13, "DES cipher for IPsec"); 166 break; 167 case SADB_X_EALG_BLOWFISHCBC: 168 if (ratecheck(&blfwarn, &ipsec_warn_interval)) 169 gone_in(13, "Blowfish cipher for IPsec"); 170 break; 171 case SADB_X_EALG_CAST128CBC: 172 if (ratecheck(&castwarn, &ipsec_warn_interval)) 173 gone_in(13, "CAST cipher for IPsec"); 174 break; 175 case SADB_X_EALG_CAMELLIACBC: 176 if (ratecheck(&camelliawarn, &ipsec_warn_interval)) 177 gone_in(13, "Camellia cipher for IPsec"); 178 break; 179 } 180 181 /* subtract off the salt, RFC4106, 8.1 and RFC3686, 5.1 */ 182 keylen = _KEYLEN(sav->key_enc) - SAV_ISCTRORGCM(sav) * 4; 183 if (txform->minkey > keylen || keylen > txform->maxkey) { 184 DPRINTF(("%s: invalid key length %u, must be in the range " 185 "[%u..%u] for algorithm %s\n", __func__, 186 keylen, txform->minkey, txform->maxkey, 187 txform->name)); 188 return EINVAL; 189 } 190 191 if (SAV_ISCTRORGCM(sav)) 192 sav->ivlen = 8; /* RFC4106 3.1 and RFC3686 3.1 */ 193 else 194 sav->ivlen = txform->ivsize; 195 196 memset(&csp, 0, sizeof(csp)); 197 198 /* 199 * Setup AH-related state. 200 */ 201 if (sav->alg_auth != 0) { 202 error = ah_init0(sav, xsp, &csp); 203 if (error) 204 return error; 205 } 206 207 /* NB: override anything set in ah_init0 */ 208 sav->tdb_xform = xsp; 209 sav->tdb_encalgxform = txform; 210 211 /* 212 * Whenever AES-GCM is used for encryption, one 213 * of the AES authentication algorithms is chosen 214 * as well, based on the key size. 215 */ 216 if (sav->alg_enc == SADB_X_EALG_AESGCM16) { 217 switch (keylen) { 218 case AES_128_GMAC_KEY_LEN: 219 sav->alg_auth = SADB_X_AALG_AES128GMAC; 220 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_128; 221 break; 222 case AES_192_GMAC_KEY_LEN: 223 sav->alg_auth = SADB_X_AALG_AES192GMAC; 224 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_192; 225 break; 226 case AES_256_GMAC_KEY_LEN: 227 sav->alg_auth = SADB_X_AALG_AES256GMAC; 228 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_256; 229 break; 230 default: 231 DPRINTF(("%s: invalid key length %u" 232 "for algorithm %s\n", __func__, 233 keylen, txform->name)); 234 return EINVAL; 235 } 236 csp.csp_mode = CSP_MODE_AEAD; 237 } else if (sav->alg_auth != 0) 238 csp.csp_mode = CSP_MODE_ETA; 239 else 240 csp.csp_mode = CSP_MODE_CIPHER; 241 242 /* Initialize crypto session. */ 243 csp.csp_cipher_alg = sav->tdb_encalgxform->type; 244 csp.csp_cipher_key = sav->key_enc->key_data; 245 csp.csp_cipher_klen = _KEYBITS(sav->key_enc) / 8 - 246 SAV_ISCTRORGCM(sav) * 4; 247 csp.csp_ivlen = txform->ivsize; 248 249 error = crypto_newsession(&sav->tdb_cryptoid, &csp, V_crypto_support); 250 return error; 251 } 252 253 /* 254 * Paranoia. 255 */ 256 static int 257 esp_zeroize(struct secasvar *sav) 258 { 259 /* NB: ah_zerorize free's the crypto session state */ 260 int error = ah_zeroize(sav); 261 262 if (sav->key_enc) 263 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc)); 264 sav->tdb_encalgxform = NULL; 265 sav->tdb_xform = NULL; 266 return error; 267 } 268 269 /* 270 * ESP input processing, called (eventually) through the protocol switch. 271 */ 272 static int 273 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 274 { 275 IPSEC_DEBUG_DECLARE(char buf[128]); 276 const struct auth_hash *esph; 277 const struct enc_xform *espx; 278 struct xform_data *xd; 279 struct cryptop *crp; 280 struct newesp *esp; 281 uint8_t *ivp; 282 crypto_session_t cryptoid; 283 int alen, error, hlen, plen; 284 285 IPSEC_ASSERT(sav != NULL, ("null SA")); 286 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); 287 288 error = EINVAL; 289 /* Valid IP Packet length ? */ 290 if ( (skip&3) || (m->m_pkthdr.len&3) ){ 291 DPRINTF(("%s: misaligned packet, skip %u pkt len %u", 292 __func__, skip, m->m_pkthdr.len)); 293 ESPSTAT_INC(esps_badilen); 294 goto bad; 295 } 296 297 if (m->m_len < skip + sizeof(*esp)) { 298 m = m_pullup(m, skip + sizeof(*esp)); 299 if (m == NULL) { 300 DPRINTF(("%s: cannot pullup header\n", __func__)); 301 ESPSTAT_INC(esps_hdrops); /*XXX*/ 302 error = ENOBUFS; 303 goto bad; 304 } 305 } 306 esp = (struct newesp *)(mtod(m, caddr_t) + skip); 307 308 esph = sav->tdb_authalgxform; 309 espx = sav->tdb_encalgxform; 310 311 /* Determine the ESP header and auth length */ 312 if (sav->flags & SADB_X_EXT_OLD) 313 hlen = sizeof (struct esp) + sav->ivlen; 314 else 315 hlen = sizeof (struct newesp) + sav->ivlen; 316 317 alen = xform_ah_authsize(esph); 318 319 /* 320 * Verify payload length is multiple of encryption algorithm 321 * block size. 322 * 323 * NB: This works for the null algorithm because the blocksize 324 * is 4 and all packets must be 4-byte aligned regardless 325 * of the algorithm. 326 */ 327 plen = m->m_pkthdr.len - (skip + hlen + alen); 328 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 329 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 330 " SA %s/%08lx\n", __func__, plen, espx->blocksize, 331 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 332 (u_long)ntohl(sav->spi))); 333 ESPSTAT_INC(esps_badilen); 334 goto bad; 335 } 336 337 /* 338 * Check sequence number. 339 */ 340 SECASVAR_LOCK(sav); 341 if (esph != NULL && sav->replay != NULL && sav->replay->wsize != 0) { 342 if (ipsec_chkreplay(ntohl(esp->esp_seq), sav) == 0) { 343 SECASVAR_UNLOCK(sav); 344 DPRINTF(("%s: packet replay check for %s\n", __func__, 345 ipsec_sa2str(sav, buf, sizeof(buf)))); 346 ESPSTAT_INC(esps_replay); 347 error = EACCES; 348 goto bad; 349 } 350 } 351 cryptoid = sav->tdb_cryptoid; 352 SECASVAR_UNLOCK(sav); 353 354 /* Update the counters */ 355 ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen)); 356 357 /* Get crypto descriptors */ 358 crp = crypto_getreq(cryptoid, M_NOWAIT); 359 if (crp == NULL) { 360 DPRINTF(("%s: failed to acquire crypto descriptors\n", 361 __func__)); 362 ESPSTAT_INC(esps_crypto); 363 error = ENOBUFS; 364 goto bad; 365 } 366 367 /* Get IPsec-specific opaque pointer */ 368 xd = malloc(sizeof(*xd), M_XDATA, M_NOWAIT | M_ZERO); 369 if (xd == NULL) { 370 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 371 ESPSTAT_INC(esps_crypto); 372 crypto_freereq(crp); 373 error = ENOBUFS; 374 goto bad; 375 } 376 377 if (esph != NULL) { 378 crp->crp_op = CRYPTO_OP_VERIFY_DIGEST; 379 crp->crp_aad_start = skip; 380 if (SAV_ISGCM(sav)) 381 crp->crp_aad_length = 8; /* RFC4106 5, SPI + SN */ 382 else 383 crp->crp_aad_length = hlen; 384 crp->crp_digest_start = m->m_pkthdr.len - alen; 385 } 386 387 /* Crypto operation descriptor */ 388 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 389 crp->crp_flags = CRYPTO_F_CBIFSYNC; 390 if (V_async_crypto) 391 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 392 crp->crp_mbuf = m; 393 crp->crp_buf_type = CRYPTO_BUF_MBUF; 394 crp->crp_callback = esp_input_cb; 395 crp->crp_opaque = xd; 396 397 /* These are passed as-is to the callback */ 398 xd->sav = sav; 399 xd->protoff = protoff; 400 xd->skip = skip; 401 xd->cryptoid = cryptoid; 402 xd->vnet = curvnet; 403 404 /* Decryption descriptor */ 405 crp->crp_op |= CRYPTO_OP_DECRYPT; 406 crp->crp_payload_start = skip + hlen; 407 crp->crp_payload_length = m->m_pkthdr.len - (skip + hlen + alen); 408 409 if (SAV_ISCTRORGCM(sav)) { 410 ivp = &crp->crp_iv[0]; 411 412 /* GCM IV Format: RFC4106 4 */ 413 /* CTR IV Format: RFC3686 4 */ 414 /* Salt is last four bytes of key, RFC4106 8.1 */ 415 /* Nonce is last four bytes of key, RFC3686 5.1 */ 416 memcpy(ivp, sav->key_enc->key_data + 417 _KEYLEN(sav->key_enc) - 4, 4); 418 419 if (SAV_ISCTR(sav)) { 420 /* Initial block counter is 1, RFC3686 4 */ 421 be32enc(&ivp[sav->ivlen + 4], 1); 422 } 423 424 m_copydata(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); 425 crp->crp_flags |= CRYPTO_F_IV_SEPARATE; 426 } else if (sav->ivlen != 0) 427 crp->crp_iv_start = skip + hlen - sav->ivlen; 428 429 return (crypto_dispatch(crp)); 430 bad: 431 m_freem(m); 432 key_freesav(&sav); 433 return (error); 434 } 435 436 /* 437 * ESP input callback from the crypto driver. 438 */ 439 static int 440 esp_input_cb(struct cryptop *crp) 441 { 442 IPSEC_DEBUG_DECLARE(char buf[128]); 443 uint8_t lastthree[3]; 444 const struct auth_hash *esph; 445 struct mbuf *m; 446 struct xform_data *xd; 447 struct secasvar *sav; 448 struct secasindex *saidx; 449 crypto_session_t cryptoid; 450 int hlen, skip, protoff, error, alen; 451 452 m = crp->crp_mbuf; 453 xd = crp->crp_opaque; 454 CURVNET_SET(xd->vnet); 455 sav = xd->sav; 456 skip = xd->skip; 457 protoff = xd->protoff; 458 cryptoid = xd->cryptoid; 459 saidx = &sav->sah->saidx; 460 esph = sav->tdb_authalgxform; 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_session, &cryptoid) != 0) 467 crypto_freesession(cryptoid); 468 xd->cryptoid = crp->crp_session; 469 CURVNET_RESTORE(); 470 return (crypto_dispatch(crp)); 471 } 472 473 /* EBADMSG indicates authentication failure. */ 474 if (!(crp->crp_etype == EBADMSG && esph != NULL)) { 475 ESPSTAT_INC(esps_noxform); 476 DPRINTF(("%s: crypto error %d\n", __func__, 477 crp->crp_etype)); 478 error = crp->crp_etype; 479 goto bad; 480 } 481 } 482 483 /* Shouldn't happen... */ 484 if (m == NULL) { 485 ESPSTAT_INC(esps_crypto); 486 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 487 error = EINVAL; 488 goto bad; 489 } 490 ESPSTAT_INC(esps_hist[sav->alg_enc]); 491 492 /* If authentication was performed, check now. */ 493 if (esph != NULL) { 494 alen = xform_ah_authsize(esph); 495 AHSTAT_INC(ahs_hist[sav->alg_auth]); 496 if (crp->crp_etype == EBADMSG) { 497 DPRINTF(("%s: authentication hash mismatch for " 498 "packet in SA %s/%08lx\n", __func__, 499 ipsec_address(&saidx->dst, buf, sizeof(buf)), 500 (u_long) ntohl(sav->spi))); 501 ESPSTAT_INC(esps_badauth); 502 error = EACCES; 503 goto bad; 504 } 505 m->m_flags |= M_AUTHIPDGM; 506 /* Remove trailing authenticator */ 507 m_adj(m, -alen); 508 } 509 510 /* Release the crypto descriptors */ 511 free(xd, M_XDATA), xd = NULL; 512 crypto_freereq(crp), crp = NULL; 513 514 /* 515 * Packet is now decrypted. 516 */ 517 m->m_flags |= M_DECRYPTED; 518 519 /* 520 * Update replay sequence number, if appropriate. 521 */ 522 if (sav->replay) { 523 u_int32_t seq; 524 525 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 526 sizeof (seq), (caddr_t) &seq); 527 SECASVAR_LOCK(sav); 528 if (ipsec_updatereplay(ntohl(seq), sav)) { 529 SECASVAR_UNLOCK(sav); 530 DPRINTF(("%s: packet replay check for %s\n", __func__, 531 ipsec_sa2str(sav, buf, sizeof(buf)))); 532 ESPSTAT_INC(esps_replay); 533 error = EACCES; 534 goto bad; 535 } 536 SECASVAR_UNLOCK(sav); 537 } 538 539 /* Determine the ESP header length */ 540 if (sav->flags & SADB_X_EXT_OLD) 541 hlen = sizeof (struct esp) + sav->ivlen; 542 else 543 hlen = sizeof (struct newesp) + sav->ivlen; 544 545 /* Remove the ESP header and IV from the mbuf. */ 546 error = m_striphdr(m, skip, hlen); 547 if (error) { 548 ESPSTAT_INC(esps_hdrops); 549 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 550 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 551 (u_long) ntohl(sav->spi))); 552 goto bad; 553 } 554 555 /* Save the last three bytes of decrypted data */ 556 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 557 558 /* Verify pad length */ 559 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 560 ESPSTAT_INC(esps_badilen); 561 DPRINTF(("%s: invalid padding length %d for %u byte packet " 562 "in SA %s/%08lx\n", __func__, lastthree[1], 563 m->m_pkthdr.len - skip, 564 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 565 (u_long) ntohl(sav->spi))); 566 error = EINVAL; 567 goto bad; 568 } 569 570 /* Verify correct decryption by checking the last padding bytes */ 571 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 572 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 573 ESPSTAT_INC(esps_badenc); 574 DPRINTF(("%s: decryption failed for packet in " 575 "SA %s/%08lx\n", __func__, ipsec_address( 576 &sav->sah->saidx.dst, buf, sizeof(buf)), 577 (u_long) ntohl(sav->spi))); 578 error = EINVAL; 579 goto bad; 580 } 581 } 582 583 /* 584 * RFC4303 2.6: 585 * Silently drop packet if next header field is IPPROTO_NONE. 586 */ 587 if (lastthree[2] == IPPROTO_NONE) 588 goto bad; 589 590 /* Trim the mbuf chain to remove trailing authenticator and padding */ 591 m_adj(m, -(lastthree[1] + 2)); 592 593 /* Restore the Next Protocol field */ 594 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 595 596 switch (saidx->dst.sa.sa_family) { 597 #ifdef INET6 598 case AF_INET6: 599 error = ipsec6_common_input_cb(m, sav, skip, protoff); 600 break; 601 #endif 602 #ifdef INET 603 case AF_INET: 604 error = ipsec4_common_input_cb(m, sav, skip, protoff); 605 break; 606 #endif 607 default: 608 panic("%s: Unexpected address family: %d saidx=%p", __func__, 609 saidx->dst.sa.sa_family, saidx); 610 } 611 CURVNET_RESTORE(); 612 return error; 613 bad: 614 CURVNET_RESTORE(); 615 if (sav != NULL) 616 key_freesav(&sav); 617 if (m != NULL) 618 m_freem(m); 619 if (xd != NULL) 620 free(xd, M_XDATA); 621 if (crp != NULL) 622 crypto_freereq(crp); 623 return error; 624 } 625 /* 626 * ESP output routine, called by ipsec[46]_perform_request(). 627 */ 628 static int 629 esp_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav, 630 u_int idx, int skip, int protoff) 631 { 632 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]); 633 struct cryptop *crp; 634 const struct auth_hash *esph; 635 const struct enc_xform *espx; 636 struct mbuf *mo = NULL; 637 struct xform_data *xd; 638 struct secasindex *saidx; 639 unsigned char *pad; 640 uint8_t *ivp; 641 uint64_t cntr; 642 crypto_session_t cryptoid; 643 int hlen, rlen, padding, blks, alen, i, roff; 644 int error, maxpacketsize; 645 uint8_t prot; 646 647 IPSEC_ASSERT(sav != NULL, ("null SA")); 648 esph = sav->tdb_authalgxform; 649 espx = sav->tdb_encalgxform; 650 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 651 652 if (sav->flags & SADB_X_EXT_OLD) 653 hlen = sizeof (struct esp) + sav->ivlen; 654 else 655 hlen = sizeof (struct newesp) + sav->ivlen; 656 657 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 658 /* 659 * RFC4303 2.4 Requires 4 byte alignment. 660 */ 661 blks = MAX(4, espx->blocksize); /* Cipher blocksize */ 662 663 /* XXX clamp padding length a la KAME??? */ 664 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 665 666 alen = xform_ah_authsize(esph); 667 668 ESPSTAT_INC(esps_output); 669 670 saidx = &sav->sah->saidx; 671 /* Check for maximum packet size violations. */ 672 switch (saidx->dst.sa.sa_family) { 673 #ifdef INET 674 case AF_INET: 675 maxpacketsize = IP_MAXPACKET; 676 break; 677 #endif /* INET */ 678 #ifdef INET6 679 case AF_INET6: 680 maxpacketsize = IPV6_MAXPACKET; 681 break; 682 #endif /* INET6 */ 683 default: 684 DPRINTF(("%s: unknown/unsupported protocol " 685 "family %d, SA %s/%08lx\n", __func__, 686 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst, 687 buf, sizeof(buf)), (u_long) ntohl(sav->spi))); 688 ESPSTAT_INC(esps_nopf); 689 error = EPFNOSUPPORT; 690 goto bad; 691 } 692 /* 693 DPRINTF(("%s: skip %d hlen %d rlen %d padding %d alen %d blksd %d\n", 694 __func__, skip, hlen, rlen, padding, alen, blks)); */ 695 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 696 DPRINTF(("%s: packet in SA %s/%08lx got too big " 697 "(len %u, max len %u)\n", __func__, 698 ipsec_address(&saidx->dst, buf, sizeof(buf)), 699 (u_long) ntohl(sav->spi), 700 skip + hlen + rlen + padding + alen, maxpacketsize)); 701 ESPSTAT_INC(esps_toobig); 702 error = EMSGSIZE; 703 goto bad; 704 } 705 706 /* Update the counters. */ 707 ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip); 708 709 m = m_unshare(m, M_NOWAIT); 710 if (m == NULL) { 711 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 712 ipsec_address(&saidx->dst, buf, sizeof(buf)), 713 (u_long) ntohl(sav->spi))); 714 ESPSTAT_INC(esps_hdrops); 715 error = ENOBUFS; 716 goto bad; 717 } 718 719 /* Inject ESP header. */ 720 mo = m_makespace(m, skip, hlen, &roff); 721 if (mo == NULL) { 722 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 723 __func__, hlen, ipsec_address(&saidx->dst, buf, 724 sizeof(buf)), (u_long) ntohl(sav->spi))); 725 ESPSTAT_INC(esps_hdrops); /* XXX diffs from openbsd */ 726 error = ENOBUFS; 727 goto bad; 728 } 729 730 /* Initialize ESP header. */ 731 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, 732 sizeof(uint32_t)); 733 SECASVAR_LOCK(sav); 734 if (sav->replay) { 735 uint32_t replay; 736 737 #ifdef REGRESSION 738 /* Emulate replay attack when ipsec_replay is TRUE. */ 739 if (!V_ipsec_replay) 740 #endif 741 sav->replay->count++; 742 replay = htonl(sav->replay->count); 743 744 bcopy((caddr_t) &replay, mtod(mo, caddr_t) + roff + 745 sizeof(uint32_t), sizeof(uint32_t)); 746 } 747 cryptoid = sav->tdb_cryptoid; 748 if (SAV_ISCTRORGCM(sav)) 749 cntr = sav->cntr++; 750 SECASVAR_UNLOCK(sav); 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(("%s: m_pad failed for SA %s/%08lx\n", __func__, 759 ipsec_address(&saidx->dst, buf, sizeof(buf)), 760 (u_long) ntohl(sav->spi))); 761 m = NULL; /* NB: free'd by m_pad */ 762 error = ENOBUFS; 763 goto bad; 764 } 765 766 /* 767 * Add padding: random, zero, or self-describing. 768 * XXX catch unexpected setting 769 */ 770 switch (sav->flags & SADB_X_EXT_PMASK) { 771 case SADB_X_EXT_PRAND: 772 arc4random_buf(pad, padding - 2); 773 break; 774 case SADB_X_EXT_PZERO: 775 bzero(pad, padding - 2); 776 break; 777 case SADB_X_EXT_PSEQ: 778 for (i = 0; i < padding - 2; i++) 779 pad[i] = i+1; 780 break; 781 } 782 783 /* Fix padding length and Next Protocol in padding itself. */ 784 pad[padding - 2] = padding - 2; 785 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 786 787 /* Fix Next Protocol in IPv4/IPv6 header. */ 788 prot = IPPROTO_ESP; 789 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 790 791 /* Get crypto descriptor. */ 792 crp = crypto_getreq(cryptoid, M_NOWAIT); 793 if (crp == NULL) { 794 DPRINTF(("%s: failed to acquire crypto descriptor\n", 795 __func__)); 796 ESPSTAT_INC(esps_crypto); 797 error = ENOBUFS; 798 goto bad; 799 } 800 801 /* IPsec-specific opaque crypto info. */ 802 xd = malloc(sizeof(struct xform_data), M_XDATA, M_NOWAIT | M_ZERO); 803 if (xd == NULL) { 804 crypto_freereq(crp); 805 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 806 ESPSTAT_INC(esps_crypto); 807 error = ENOBUFS; 808 goto bad; 809 } 810 811 /* Encryption descriptor. */ 812 crp->crp_payload_start = skip + hlen; 813 crp->crp_payload_length = m->m_pkthdr.len - (skip + hlen + alen); 814 crp->crp_op = CRYPTO_OP_ENCRYPT; 815 816 /* Encryption operation. */ 817 if (SAV_ISCTRORGCM(sav)) { 818 ivp = &crp->crp_iv[0]; 819 820 /* GCM IV Format: RFC4106 4 */ 821 /* CTR IV Format: RFC3686 4 */ 822 /* Salt is last four bytes of key, RFC4106 8.1 */ 823 /* Nonce is last four bytes of key, RFC3686 5.1 */ 824 memcpy(ivp, sav->key_enc->key_data + 825 _KEYLEN(sav->key_enc) - 4, 4); 826 be64enc(&ivp[4], cntr); 827 if (SAV_ISCTR(sav)) { 828 /* Initial block counter is 1, RFC3686 4 */ 829 /* XXXAE: should we use this only for first packet? */ 830 be32enc(&ivp[sav->ivlen + 4], 1); 831 } 832 833 m_copyback(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); 834 crp->crp_flags |= CRYPTO_F_IV_SEPARATE; 835 } else if (sav->ivlen != 0) { 836 crp->crp_iv_start = skip + hlen - sav->ivlen; 837 crp->crp_flags |= CRYPTO_F_IV_GENERATE; 838 } 839 840 /* Callback parameters */ 841 xd->sp = sp; 842 xd->sav = sav; 843 xd->idx = idx; 844 xd->cryptoid = cryptoid; 845 xd->vnet = curvnet; 846 847 /* Crypto operation descriptor. */ 848 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 849 crp->crp_flags |= CRYPTO_F_CBIFSYNC; 850 if (V_async_crypto) 851 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 852 crp->crp_mbuf = m; 853 crp->crp_buf_type = CRYPTO_BUF_MBUF; 854 crp->crp_callback = esp_output_cb; 855 crp->crp_opaque = xd; 856 857 if (esph) { 858 /* Authentication descriptor. */ 859 crp->crp_op |= CRYPTO_OP_COMPUTE_DIGEST; 860 crp->crp_aad_start = skip; 861 if (SAV_ISGCM(sav)) 862 crp->crp_aad_length = 8; /* RFC4106 5, SPI + SN */ 863 else 864 crp->crp_aad_length = hlen; 865 crp->crp_digest_start = m->m_pkthdr.len - alen; 866 } 867 868 return crypto_dispatch(crp); 869 bad: 870 if (m) 871 m_freem(m); 872 key_freesav(&sav); 873 key_freesp(&sp); 874 return (error); 875 } 876 /* 877 * ESP output callback from the crypto driver. 878 */ 879 static int 880 esp_output_cb(struct cryptop *crp) 881 { 882 struct xform_data *xd; 883 struct secpolicy *sp; 884 struct secasvar *sav; 885 struct mbuf *m; 886 crypto_session_t cryptoid; 887 u_int idx; 888 int error; 889 890 xd = (struct xform_data *) crp->crp_opaque; 891 CURVNET_SET(xd->vnet); 892 m = (struct mbuf *) crp->crp_buf; 893 sp = xd->sp; 894 sav = xd->sav; 895 idx = xd->idx; 896 cryptoid = xd->cryptoid; 897 898 /* Check for crypto errors. */ 899 if (crp->crp_etype) { 900 if (crp->crp_etype == EAGAIN) { 901 /* Reset the session ID */ 902 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 903 crypto_freesession(cryptoid); 904 xd->cryptoid = crp->crp_session; 905 CURVNET_RESTORE(); 906 return (crypto_dispatch(crp)); 907 } 908 ESPSTAT_INC(esps_noxform); 909 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 910 error = crp->crp_etype; 911 m_freem(m); 912 goto bad; 913 } 914 915 /* Shouldn't happen... */ 916 if (m == NULL) { 917 ESPSTAT_INC(esps_crypto); 918 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 919 error = EINVAL; 920 goto bad; 921 } 922 free(xd, M_XDATA); 923 crypto_freereq(crp); 924 ESPSTAT_INC(esps_hist[sav->alg_enc]); 925 if (sav->tdb_authalgxform != NULL) 926 AHSTAT_INC(ahs_hist[sav->alg_auth]); 927 928 #ifdef REGRESSION 929 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 930 if (V_ipsec_integrity) { 931 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN]; 932 const struct auth_hash *esph; 933 934 /* 935 * Corrupt HMAC if we want to test integrity verification of 936 * the other side. 937 */ 938 esph = sav->tdb_authalgxform; 939 if (esph != NULL) { 940 int alen; 941 942 alen = xform_ah_authsize(esph); 943 m_copyback(m, m->m_pkthdr.len - alen, 944 alen, ipseczeroes); 945 } 946 } 947 #endif 948 949 /* NB: m is reclaimed by ipsec_process_done. */ 950 error = ipsec_process_done(m, sp, sav, idx); 951 CURVNET_RESTORE(); 952 return (error); 953 bad: 954 CURVNET_RESTORE(); 955 free(xd, M_XDATA); 956 crypto_freereq(crp); 957 key_freesav(&sav); 958 key_freesp(&sp); 959 return (error); 960 } 961 962 static struct xformsw esp_xformsw = { 963 .xf_type = XF_ESP, 964 .xf_name = "IPsec ESP", 965 .xf_init = esp_init, 966 .xf_zeroize = esp_zeroize, 967 .xf_input = esp_input, 968 .xf_output = esp_output, 969 }; 970 971 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 972 xform_attach, &esp_xformsw); 973 SYSUNINIT(esp_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 974 xform_detach, &esp_xformsw); 975