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 /* Generate or read cipher IV. */ 410 if (SAV_ISCTRORGCM(sav)) { 411 ivp = &crp->crp_iv[0]; 412 413 /* 414 * AES-GCM and AES-CTR use similar cipher IV formats 415 * defined in RFC 4106 section 4 and RFC 3686 section 416 * 4, respectively. 417 * 418 * The first 4 bytes of the cipher IV contain an 419 * implicit salt, or nonce, obtained from the last 4 420 * bytes of the encryption key. The next 8 bytes hold 421 * an explicit IV unique to each packet. This 422 * explicit IV is used as the ESP IV for the packet. 423 * The last 4 bytes hold a big-endian block counter 424 * incremented for each block. For AES-GCM, the block 425 * counter's initial value is defined as part of the 426 * algorithm. For AES-CTR, the block counter's 427 * initial value for each packet is defined as 1 by 428 * RFC 3686. 429 * 430 * ------------------------------------------ 431 * | Salt | Explicit ESP IV | Block Counter | 432 * ------------------------------------------ 433 * 4 bytes 8 bytes 4 bytes 434 */ 435 memcpy(ivp, sav->key_enc->key_data + 436 _KEYLEN(sav->key_enc) - 4, 4); 437 m_copydata(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); 438 if (SAV_ISCTR(sav)) { 439 be32enc(&ivp[sav->ivlen + 4], 1); 440 } 441 crp->crp_flags |= CRYPTO_F_IV_SEPARATE; 442 } else if (sav->ivlen != 0) 443 crp->crp_iv_start = skip + hlen - sav->ivlen; 444 445 return (crypto_dispatch(crp)); 446 bad: 447 m_freem(m); 448 key_freesav(&sav); 449 return (error); 450 } 451 452 /* 453 * ESP input callback from the crypto driver. 454 */ 455 static int 456 esp_input_cb(struct cryptop *crp) 457 { 458 IPSEC_DEBUG_DECLARE(char buf[128]); 459 uint8_t lastthree[3]; 460 const struct auth_hash *esph; 461 struct mbuf *m; 462 struct xform_data *xd; 463 struct secasvar *sav; 464 struct secasindex *saidx; 465 crypto_session_t cryptoid; 466 int hlen, skip, protoff, error, alen; 467 468 m = crp->crp_mbuf; 469 xd = crp->crp_opaque; 470 CURVNET_SET(xd->vnet); 471 sav = xd->sav; 472 skip = xd->skip; 473 protoff = xd->protoff; 474 cryptoid = xd->cryptoid; 475 saidx = &sav->sah->saidx; 476 esph = sav->tdb_authalgxform; 477 478 /* Check for crypto errors */ 479 if (crp->crp_etype) { 480 if (crp->crp_etype == EAGAIN) { 481 /* Reset the session ID */ 482 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 483 crypto_freesession(cryptoid); 484 xd->cryptoid = crp->crp_session; 485 CURVNET_RESTORE(); 486 return (crypto_dispatch(crp)); 487 } 488 489 /* EBADMSG indicates authentication failure. */ 490 if (!(crp->crp_etype == EBADMSG && esph != NULL)) { 491 ESPSTAT_INC(esps_noxform); 492 DPRINTF(("%s: crypto error %d\n", __func__, 493 crp->crp_etype)); 494 error = crp->crp_etype; 495 goto bad; 496 } 497 } 498 499 /* Shouldn't happen... */ 500 if (m == NULL) { 501 ESPSTAT_INC(esps_crypto); 502 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 503 error = EINVAL; 504 goto bad; 505 } 506 ESPSTAT_INC(esps_hist[sav->alg_enc]); 507 508 /* If authentication was performed, check now. */ 509 if (esph != NULL) { 510 alen = xform_ah_authsize(esph); 511 AHSTAT_INC(ahs_hist[sav->alg_auth]); 512 if (crp->crp_etype == EBADMSG) { 513 DPRINTF(("%s: authentication hash mismatch for " 514 "packet in SA %s/%08lx\n", __func__, 515 ipsec_address(&saidx->dst, buf, sizeof(buf)), 516 (u_long) ntohl(sav->spi))); 517 ESPSTAT_INC(esps_badauth); 518 error = EACCES; 519 goto bad; 520 } 521 m->m_flags |= M_AUTHIPDGM; 522 /* Remove trailing authenticator */ 523 m_adj(m, -alen); 524 } 525 526 /* Release the crypto descriptors */ 527 free(xd, M_XDATA), xd = NULL; 528 crypto_freereq(crp), crp = NULL; 529 530 /* 531 * Packet is now decrypted. 532 */ 533 m->m_flags |= M_DECRYPTED; 534 535 /* 536 * Update replay sequence number, if appropriate. 537 */ 538 if (sav->replay) { 539 u_int32_t seq; 540 541 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 542 sizeof (seq), (caddr_t) &seq); 543 SECASVAR_LOCK(sav); 544 if (ipsec_updatereplay(ntohl(seq), sav)) { 545 SECASVAR_UNLOCK(sav); 546 DPRINTF(("%s: packet replay check for %s\n", __func__, 547 ipsec_sa2str(sav, buf, sizeof(buf)))); 548 ESPSTAT_INC(esps_replay); 549 error = EACCES; 550 goto bad; 551 } 552 SECASVAR_UNLOCK(sav); 553 } 554 555 /* Determine the ESP header length */ 556 if (sav->flags & SADB_X_EXT_OLD) 557 hlen = sizeof (struct esp) + sav->ivlen; 558 else 559 hlen = sizeof (struct newesp) + sav->ivlen; 560 561 /* Remove the ESP header and IV from the mbuf. */ 562 error = m_striphdr(m, skip, hlen); 563 if (error) { 564 ESPSTAT_INC(esps_hdrops); 565 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 566 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 567 (u_long) ntohl(sav->spi))); 568 goto bad; 569 } 570 571 /* Save the last three bytes of decrypted data */ 572 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 573 574 /* Verify pad length */ 575 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 576 ESPSTAT_INC(esps_badilen); 577 DPRINTF(("%s: invalid padding length %d for %u byte packet " 578 "in SA %s/%08lx\n", __func__, lastthree[1], 579 m->m_pkthdr.len - skip, 580 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 581 (u_long) ntohl(sav->spi))); 582 error = EINVAL; 583 goto bad; 584 } 585 586 /* Verify correct decryption by checking the last padding bytes */ 587 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 588 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 589 ESPSTAT_INC(esps_badenc); 590 DPRINTF(("%s: decryption failed for packet in " 591 "SA %s/%08lx\n", __func__, ipsec_address( 592 &sav->sah->saidx.dst, buf, sizeof(buf)), 593 (u_long) ntohl(sav->spi))); 594 error = EINVAL; 595 goto bad; 596 } 597 } 598 599 /* 600 * RFC4303 2.6: 601 * Silently drop packet if next header field is IPPROTO_NONE. 602 */ 603 if (lastthree[2] == IPPROTO_NONE) 604 goto bad; 605 606 /* Trim the mbuf chain to remove trailing authenticator and padding */ 607 m_adj(m, -(lastthree[1] + 2)); 608 609 /* Restore the Next Protocol field */ 610 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 611 612 switch (saidx->dst.sa.sa_family) { 613 #ifdef INET6 614 case AF_INET6: 615 error = ipsec6_common_input_cb(m, sav, skip, protoff); 616 break; 617 #endif 618 #ifdef INET 619 case AF_INET: 620 error = ipsec4_common_input_cb(m, sav, skip, protoff); 621 break; 622 #endif 623 default: 624 panic("%s: Unexpected address family: %d saidx=%p", __func__, 625 saidx->dst.sa.sa_family, saidx); 626 } 627 CURVNET_RESTORE(); 628 return error; 629 bad: 630 CURVNET_RESTORE(); 631 if (sav != NULL) 632 key_freesav(&sav); 633 if (m != NULL) 634 m_freem(m); 635 if (xd != NULL) 636 free(xd, M_XDATA); 637 if (crp != NULL) 638 crypto_freereq(crp); 639 return error; 640 } 641 /* 642 * ESP output routine, called by ipsec[46]_perform_request(). 643 */ 644 static int 645 esp_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav, 646 u_int idx, int skip, int protoff) 647 { 648 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]); 649 struct cryptop *crp; 650 const struct auth_hash *esph; 651 const struct enc_xform *espx; 652 struct mbuf *mo = NULL; 653 struct xform_data *xd; 654 struct secasindex *saidx; 655 unsigned char *pad; 656 uint8_t *ivp; 657 uint64_t cntr; 658 crypto_session_t cryptoid; 659 int hlen, rlen, padding, blks, alen, i, roff; 660 int error, maxpacketsize; 661 uint8_t prot; 662 663 IPSEC_ASSERT(sav != NULL, ("null SA")); 664 esph = sav->tdb_authalgxform; 665 espx = sav->tdb_encalgxform; 666 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 667 668 if (sav->flags & SADB_X_EXT_OLD) 669 hlen = sizeof (struct esp) + sav->ivlen; 670 else 671 hlen = sizeof (struct newesp) + sav->ivlen; 672 673 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 674 /* 675 * RFC4303 2.4 Requires 4 byte alignment. 676 */ 677 blks = MAX(4, espx->blocksize); /* Cipher blocksize */ 678 679 /* XXX clamp padding length a la KAME??? */ 680 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 681 682 alen = xform_ah_authsize(esph); 683 684 ESPSTAT_INC(esps_output); 685 686 saidx = &sav->sah->saidx; 687 /* Check for maximum packet size violations. */ 688 switch (saidx->dst.sa.sa_family) { 689 #ifdef INET 690 case AF_INET: 691 maxpacketsize = IP_MAXPACKET; 692 break; 693 #endif /* INET */ 694 #ifdef INET6 695 case AF_INET6: 696 maxpacketsize = IPV6_MAXPACKET; 697 break; 698 #endif /* INET6 */ 699 default: 700 DPRINTF(("%s: unknown/unsupported protocol " 701 "family %d, SA %s/%08lx\n", __func__, 702 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst, 703 buf, sizeof(buf)), (u_long) ntohl(sav->spi))); 704 ESPSTAT_INC(esps_nopf); 705 error = EPFNOSUPPORT; 706 goto bad; 707 } 708 /* 709 DPRINTF(("%s: skip %d hlen %d rlen %d padding %d alen %d blksd %d\n", 710 __func__, skip, hlen, rlen, padding, alen, blks)); */ 711 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 712 DPRINTF(("%s: packet in SA %s/%08lx got too big " 713 "(len %u, max len %u)\n", __func__, 714 ipsec_address(&saidx->dst, buf, sizeof(buf)), 715 (u_long) ntohl(sav->spi), 716 skip + hlen + rlen + padding + alen, maxpacketsize)); 717 ESPSTAT_INC(esps_toobig); 718 error = EMSGSIZE; 719 goto bad; 720 } 721 722 /* Update the counters. */ 723 ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip); 724 725 m = m_unshare(m, M_NOWAIT); 726 if (m == NULL) { 727 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 728 ipsec_address(&saidx->dst, buf, sizeof(buf)), 729 (u_long) ntohl(sav->spi))); 730 ESPSTAT_INC(esps_hdrops); 731 error = ENOBUFS; 732 goto bad; 733 } 734 735 /* Inject ESP header. */ 736 mo = m_makespace(m, skip, hlen, &roff); 737 if (mo == NULL) { 738 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 739 __func__, hlen, ipsec_address(&saidx->dst, buf, 740 sizeof(buf)), (u_long) ntohl(sav->spi))); 741 ESPSTAT_INC(esps_hdrops); /* XXX diffs from openbsd */ 742 error = ENOBUFS; 743 goto bad; 744 } 745 746 /* Initialize ESP header. */ 747 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, 748 sizeof(uint32_t)); 749 SECASVAR_LOCK(sav); 750 if (sav->replay) { 751 uint32_t replay; 752 753 #ifdef REGRESSION 754 /* Emulate replay attack when ipsec_replay is TRUE. */ 755 if (!V_ipsec_replay) 756 #endif 757 sav->replay->count++; 758 replay = htonl(sav->replay->count); 759 760 bcopy((caddr_t) &replay, mtod(mo, caddr_t) + roff + 761 sizeof(uint32_t), sizeof(uint32_t)); 762 } 763 cryptoid = sav->tdb_cryptoid; 764 if (SAV_ISCTRORGCM(sav)) 765 cntr = sav->cntr++; 766 SECASVAR_UNLOCK(sav); 767 768 /* 769 * Add padding -- better to do it ourselves than use the crypto engine, 770 * although if/when we support compression, we'd have to do that. 771 */ 772 pad = (u_char *) m_pad(m, padding + alen); 773 if (pad == NULL) { 774 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 775 ipsec_address(&saidx->dst, buf, sizeof(buf)), 776 (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 arc4random_buf(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 descriptor. */ 808 crp = crypto_getreq(cryptoid, M_NOWAIT); 809 if (crp == NULL) { 810 DPRINTF(("%s: failed to acquire crypto descriptor\n", 811 __func__)); 812 ESPSTAT_INC(esps_crypto); 813 error = ENOBUFS; 814 goto bad; 815 } 816 817 /* IPsec-specific opaque crypto info. */ 818 xd = malloc(sizeof(struct xform_data), M_XDATA, M_NOWAIT | M_ZERO); 819 if (xd == NULL) { 820 crypto_freereq(crp); 821 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 822 ESPSTAT_INC(esps_crypto); 823 error = ENOBUFS; 824 goto bad; 825 } 826 827 /* Encryption descriptor. */ 828 crp->crp_payload_start = skip + hlen; 829 crp->crp_payload_length = m->m_pkthdr.len - (skip + hlen + alen); 830 crp->crp_op = CRYPTO_OP_ENCRYPT; 831 832 /* Generate cipher and ESP IVs. */ 833 ivp = &crp->crp_iv[0]; 834 if (SAV_ISCTRORGCM(sav)) { 835 /* 836 * See comment in esp_input() for details on the 837 * cipher IV. A simple per-SA counter stored in 838 * 'cntr' is used as the explicit ESP IV. 839 */ 840 memcpy(ivp, sav->key_enc->key_data + 841 _KEYLEN(sav->key_enc) - 4, 4); 842 be64enc(&ivp[4], cntr); 843 if (SAV_ISCTR(sav)) { 844 be32enc(&ivp[sav->ivlen + 4], 1); 845 } 846 m_copyback(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); 847 crp->crp_flags |= CRYPTO_F_IV_SEPARATE; 848 } else if (sav->ivlen != 0) { 849 arc4rand(ivp, sav->ivlen, 0); 850 crp->crp_iv_start = skip + hlen - sav->ivlen; 851 m_copyback(m, crp->crp_iv_start, sav->ivlen, ivp); 852 } 853 854 /* Callback parameters */ 855 xd->sp = sp; 856 xd->sav = sav; 857 xd->idx = idx; 858 xd->cryptoid = cryptoid; 859 xd->vnet = curvnet; 860 861 /* Crypto operation descriptor. */ 862 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 863 crp->crp_flags |= CRYPTO_F_CBIFSYNC; 864 if (V_async_crypto) 865 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 866 crp->crp_mbuf = m; 867 crp->crp_buf_type = CRYPTO_BUF_MBUF; 868 crp->crp_callback = esp_output_cb; 869 crp->crp_opaque = xd; 870 871 if (esph) { 872 /* Authentication descriptor. */ 873 crp->crp_op |= CRYPTO_OP_COMPUTE_DIGEST; 874 crp->crp_aad_start = skip; 875 if (SAV_ISGCM(sav)) 876 crp->crp_aad_length = 8; /* RFC4106 5, SPI + SN */ 877 else 878 crp->crp_aad_length = hlen; 879 crp->crp_digest_start = m->m_pkthdr.len - alen; 880 } 881 882 return crypto_dispatch(crp); 883 bad: 884 if (m) 885 m_freem(m); 886 key_freesav(&sav); 887 key_freesp(&sp); 888 return (error); 889 } 890 /* 891 * ESP output callback from the crypto driver. 892 */ 893 static int 894 esp_output_cb(struct cryptop *crp) 895 { 896 struct xform_data *xd; 897 struct secpolicy *sp; 898 struct secasvar *sav; 899 struct mbuf *m; 900 crypto_session_t cryptoid; 901 u_int idx; 902 int error; 903 904 xd = (struct xform_data *) crp->crp_opaque; 905 CURVNET_SET(xd->vnet); 906 m = (struct mbuf *) crp->crp_buf; 907 sp = xd->sp; 908 sav = xd->sav; 909 idx = xd->idx; 910 cryptoid = xd->cryptoid; 911 912 /* Check for crypto errors. */ 913 if (crp->crp_etype) { 914 if (crp->crp_etype == EAGAIN) { 915 /* Reset the session ID */ 916 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 917 crypto_freesession(cryptoid); 918 xd->cryptoid = crp->crp_session; 919 CURVNET_RESTORE(); 920 return (crypto_dispatch(crp)); 921 } 922 ESPSTAT_INC(esps_noxform); 923 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 924 error = crp->crp_etype; 925 m_freem(m); 926 goto bad; 927 } 928 929 /* Shouldn't happen... */ 930 if (m == NULL) { 931 ESPSTAT_INC(esps_crypto); 932 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 933 error = EINVAL; 934 goto bad; 935 } 936 free(xd, M_XDATA); 937 crypto_freereq(crp); 938 ESPSTAT_INC(esps_hist[sav->alg_enc]); 939 if (sav->tdb_authalgxform != NULL) 940 AHSTAT_INC(ahs_hist[sav->alg_auth]); 941 942 #ifdef REGRESSION 943 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 944 if (V_ipsec_integrity) { 945 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN]; 946 const struct auth_hash *esph; 947 948 /* 949 * Corrupt HMAC if we want to test integrity verification of 950 * the other side. 951 */ 952 esph = sav->tdb_authalgxform; 953 if (esph != NULL) { 954 int alen; 955 956 alen = xform_ah_authsize(esph); 957 m_copyback(m, m->m_pkthdr.len - alen, 958 alen, ipseczeroes); 959 } 960 } 961 #endif 962 963 /* NB: m is reclaimed by ipsec_process_done. */ 964 error = ipsec_process_done(m, sp, sav, idx); 965 CURVNET_RESTORE(); 966 return (error); 967 bad: 968 CURVNET_RESTORE(); 969 free(xd, M_XDATA); 970 crypto_freereq(crp); 971 key_freesav(&sav); 972 key_freesp(&sp); 973 return (error); 974 } 975 976 static struct xformsw esp_xformsw = { 977 .xf_type = XF_ESP, 978 .xf_name = "IPsec ESP", 979 .xf_init = esp_init, 980 .xf_zeroize = esp_zeroize, 981 .xf_input = esp_input, 982 .xf_output = esp_output, 983 }; 984 985 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 986 xform_attach, &esp_xformsw); 987 SYSUNINIT(esp_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 988 xform_detach, &esp_xformsw); 989