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, tdeswarn; 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_EALG_3DESCBC: 168 if (ratecheck(&tdeswarn, &ipsec_warn_interval)) 169 gone_in(13, "3DES cipher for IPsec"); 170 break; 171 case SADB_X_EALG_BLOWFISHCBC: 172 if (ratecheck(&blfwarn, &ipsec_warn_interval)) 173 gone_in(13, "Blowfish cipher for IPsec"); 174 break; 175 case SADB_X_EALG_CAST128CBC: 176 if (ratecheck(&castwarn, &ipsec_warn_interval)) 177 gone_in(13, "CAST cipher for IPsec"); 178 break; 179 case SADB_X_EALG_CAMELLIACBC: 180 if (ratecheck(&camelliawarn, &ipsec_warn_interval)) 181 gone_in(13, "Camellia cipher for IPsec"); 182 break; 183 } 184 185 /* subtract off the salt, RFC4106, 8.1 and RFC3686, 5.1 */ 186 keylen = _KEYLEN(sav->key_enc) - SAV_ISCTRORGCM(sav) * 4; 187 if (txform->minkey > keylen || keylen > txform->maxkey) { 188 DPRINTF(("%s: invalid key length %u, must be in the range " 189 "[%u..%u] for algorithm %s\n", __func__, 190 keylen, txform->minkey, txform->maxkey, 191 txform->name)); 192 return EINVAL; 193 } 194 195 if (SAV_ISCTRORGCM(sav)) 196 sav->ivlen = 8; /* RFC4106 3.1 and RFC3686 3.1 */ 197 else 198 sav->ivlen = txform->ivsize; 199 200 memset(&csp, 0, sizeof(csp)); 201 202 /* 203 * Setup AH-related state. 204 */ 205 if (sav->alg_auth != 0) { 206 error = ah_init0(sav, xsp, &csp); 207 if (error) 208 return error; 209 } 210 211 /* NB: override anything set in ah_init0 */ 212 sav->tdb_xform = xsp; 213 sav->tdb_encalgxform = txform; 214 215 /* 216 * Whenever AES-GCM is used for encryption, one 217 * of the AES authentication algorithms is chosen 218 * as well, based on the key size. 219 */ 220 if (sav->alg_enc == SADB_X_EALG_AESGCM16) { 221 switch (keylen) { 222 case AES_128_GMAC_KEY_LEN: 223 sav->alg_auth = SADB_X_AALG_AES128GMAC; 224 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_128; 225 break; 226 case AES_192_GMAC_KEY_LEN: 227 sav->alg_auth = SADB_X_AALG_AES192GMAC; 228 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_192; 229 break; 230 case AES_256_GMAC_KEY_LEN: 231 sav->alg_auth = SADB_X_AALG_AES256GMAC; 232 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_256; 233 break; 234 default: 235 DPRINTF(("%s: invalid key length %u" 236 "for algorithm %s\n", __func__, 237 keylen, txform->name)); 238 return EINVAL; 239 } 240 csp.csp_mode = CSP_MODE_AEAD; 241 } else if (sav->alg_auth != 0) 242 csp.csp_mode = CSP_MODE_ETA; 243 else 244 csp.csp_mode = CSP_MODE_CIPHER; 245 246 /* Initialize crypto session. */ 247 csp.csp_cipher_alg = sav->tdb_encalgxform->type; 248 csp.csp_cipher_key = sav->key_enc->key_data; 249 csp.csp_cipher_klen = _KEYBITS(sav->key_enc) / 8 - 250 SAV_ISCTRORGCM(sav) * 4; 251 csp.csp_ivlen = txform->ivsize; 252 253 error = crypto_newsession(&sav->tdb_cryptoid, &csp, V_crypto_support); 254 return error; 255 } 256 257 /* 258 * Paranoia. 259 */ 260 static int 261 esp_zeroize(struct secasvar *sav) 262 { 263 /* NB: ah_zerorize free's the crypto session state */ 264 int error = ah_zeroize(sav); 265 266 if (sav->key_enc) 267 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc)); 268 sav->tdb_encalgxform = NULL; 269 sav->tdb_xform = NULL; 270 return error; 271 } 272 273 /* 274 * ESP input processing, called (eventually) through the protocol switch. 275 */ 276 static int 277 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 278 { 279 IPSEC_DEBUG_DECLARE(char buf[128]); 280 const struct auth_hash *esph; 281 const struct enc_xform *espx; 282 struct xform_data *xd; 283 struct cryptop *crp; 284 struct newesp *esp; 285 uint8_t *ivp; 286 crypto_session_t cryptoid; 287 int alen, error, hlen, plen; 288 289 IPSEC_ASSERT(sav != NULL, ("null SA")); 290 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); 291 292 error = EINVAL; 293 /* Valid IP Packet length ? */ 294 if ( (skip&3) || (m->m_pkthdr.len&3) ){ 295 DPRINTF(("%s: misaligned packet, skip %u pkt len %u", 296 __func__, skip, m->m_pkthdr.len)); 297 ESPSTAT_INC(esps_badilen); 298 goto bad; 299 } 300 301 if (m->m_len < skip + sizeof(*esp)) { 302 m = m_pullup(m, skip + sizeof(*esp)); 303 if (m == NULL) { 304 DPRINTF(("%s: cannot pullup header\n", __func__)); 305 ESPSTAT_INC(esps_hdrops); /*XXX*/ 306 error = ENOBUFS; 307 goto bad; 308 } 309 } 310 esp = (struct newesp *)(mtod(m, caddr_t) + skip); 311 312 esph = sav->tdb_authalgxform; 313 espx = sav->tdb_encalgxform; 314 315 /* Determine the ESP header and auth length */ 316 if (sav->flags & SADB_X_EXT_OLD) 317 hlen = sizeof (struct esp) + sav->ivlen; 318 else 319 hlen = sizeof (struct newesp) + sav->ivlen; 320 321 alen = xform_ah_authsize(esph); 322 323 /* 324 * Verify payload length is multiple of encryption algorithm 325 * block size. 326 * 327 * NB: This works for the null algorithm because the blocksize 328 * is 4 and all packets must be 4-byte aligned regardless 329 * of the algorithm. 330 */ 331 plen = m->m_pkthdr.len - (skip + hlen + alen); 332 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 333 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 334 " SA %s/%08lx\n", __func__, plen, espx->blocksize, 335 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 336 (u_long)ntohl(sav->spi))); 337 ESPSTAT_INC(esps_badilen); 338 goto bad; 339 } 340 341 /* 342 * Check sequence number. 343 */ 344 SECASVAR_LOCK(sav); 345 if (esph != NULL && sav->replay != NULL && sav->replay->wsize != 0) { 346 if (ipsec_chkreplay(ntohl(esp->esp_seq), sav) == 0) { 347 SECASVAR_UNLOCK(sav); 348 DPRINTF(("%s: packet replay check for %s\n", __func__, 349 ipsec_sa2str(sav, buf, sizeof(buf)))); 350 ESPSTAT_INC(esps_replay); 351 error = EACCES; 352 goto bad; 353 } 354 } 355 cryptoid = sav->tdb_cryptoid; 356 SECASVAR_UNLOCK(sav); 357 358 /* Update the counters */ 359 ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen)); 360 361 /* Get crypto descriptors */ 362 crp = crypto_getreq(cryptoid, M_NOWAIT); 363 if (crp == NULL) { 364 DPRINTF(("%s: failed to acquire crypto descriptors\n", 365 __func__)); 366 ESPSTAT_INC(esps_crypto); 367 error = ENOBUFS; 368 goto bad; 369 } 370 371 /* Get IPsec-specific opaque pointer */ 372 xd = malloc(sizeof(*xd), M_XDATA, M_NOWAIT | M_ZERO); 373 if (xd == NULL) { 374 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 375 ESPSTAT_INC(esps_crypto); 376 crypto_freereq(crp); 377 error = ENOBUFS; 378 goto bad; 379 } 380 381 if (esph != NULL) { 382 crp->crp_op = CRYPTO_OP_VERIFY_DIGEST; 383 crp->crp_aad_start = skip; 384 if (SAV_ISGCM(sav)) 385 crp->crp_aad_length = 8; /* RFC4106 5, SPI + SN */ 386 else 387 crp->crp_aad_length = hlen; 388 crp->crp_digest_start = m->m_pkthdr.len - alen; 389 } 390 391 /* Crypto operation descriptor */ 392 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 393 crp->crp_flags = CRYPTO_F_CBIFSYNC; 394 if (V_async_crypto) 395 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 396 crp->crp_mbuf = m; 397 crp->crp_buf_type = CRYPTO_BUF_MBUF; 398 crp->crp_callback = esp_input_cb; 399 crp->crp_opaque = xd; 400 401 /* These are passed as-is to the callback */ 402 xd->sav = sav; 403 xd->protoff = protoff; 404 xd->skip = skip; 405 xd->cryptoid = cryptoid; 406 xd->vnet = curvnet; 407 408 /* Decryption descriptor */ 409 crp->crp_op |= CRYPTO_OP_DECRYPT; 410 crp->crp_payload_start = skip + hlen; 411 crp->crp_payload_length = m->m_pkthdr.len - (skip + hlen + alen); 412 413 /* Generate or read cipher IV. */ 414 if (SAV_ISCTRORGCM(sav)) { 415 ivp = &crp->crp_iv[0]; 416 417 /* 418 * AES-GCM and AES-CTR use similar cipher IV formats 419 * defined in RFC 4106 section 4 and RFC 3686 section 420 * 4, respectively. 421 * 422 * The first 4 bytes of the cipher IV contain an 423 * implicit salt, or nonce, obtained from the last 4 424 * bytes of the encryption key. The next 8 bytes hold 425 * an explicit IV unique to each packet. This 426 * explicit IV is used as the ESP IV for the packet. 427 * The last 4 bytes hold a big-endian block counter 428 * incremented for each block. For AES-GCM, the block 429 * counter's initial value is defined as part of the 430 * algorithm. For AES-CTR, the block counter's 431 * initial value for each packet is defined as 1 by 432 * RFC 3686. 433 * 434 * ------------------------------------------ 435 * | Salt | Explicit ESP IV | Block Counter | 436 * ------------------------------------------ 437 * 4 bytes 8 bytes 4 bytes 438 */ 439 memcpy(ivp, sav->key_enc->key_data + 440 _KEYLEN(sav->key_enc) - 4, 4); 441 m_copydata(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); 442 if (SAV_ISCTR(sav)) { 443 be32enc(&ivp[sav->ivlen + 4], 1); 444 } 445 crp->crp_flags |= CRYPTO_F_IV_SEPARATE; 446 } else if (sav->ivlen != 0) 447 crp->crp_iv_start = skip + hlen - sav->ivlen; 448 449 return (crypto_dispatch(crp)); 450 bad: 451 m_freem(m); 452 key_freesav(&sav); 453 return (error); 454 } 455 456 /* 457 * ESP input callback from the crypto driver. 458 */ 459 static int 460 esp_input_cb(struct cryptop *crp) 461 { 462 IPSEC_DEBUG_DECLARE(char buf[128]); 463 uint8_t lastthree[3]; 464 const struct auth_hash *esph; 465 struct mbuf *m; 466 struct xform_data *xd; 467 struct secasvar *sav; 468 struct secasindex *saidx; 469 crypto_session_t cryptoid; 470 int hlen, skip, protoff, error, alen; 471 472 m = crp->crp_mbuf; 473 xd = crp->crp_opaque; 474 CURVNET_SET(xd->vnet); 475 sav = xd->sav; 476 skip = xd->skip; 477 protoff = xd->protoff; 478 cryptoid = xd->cryptoid; 479 saidx = &sav->sah->saidx; 480 esph = sav->tdb_authalgxform; 481 482 /* Check for crypto errors */ 483 if (crp->crp_etype) { 484 if (crp->crp_etype == EAGAIN) { 485 /* Reset the session ID */ 486 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 487 crypto_freesession(cryptoid); 488 xd->cryptoid = crp->crp_session; 489 CURVNET_RESTORE(); 490 return (crypto_dispatch(crp)); 491 } 492 493 /* EBADMSG indicates authentication failure. */ 494 if (!(crp->crp_etype == EBADMSG && esph != NULL)) { 495 ESPSTAT_INC(esps_noxform); 496 DPRINTF(("%s: crypto error %d\n", __func__, 497 crp->crp_etype)); 498 error = crp->crp_etype; 499 goto bad; 500 } 501 } 502 503 /* Shouldn't happen... */ 504 if (m == NULL) { 505 ESPSTAT_INC(esps_crypto); 506 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 507 error = EINVAL; 508 goto bad; 509 } 510 ESPSTAT_INC(esps_hist[sav->alg_enc]); 511 512 /* If authentication was performed, check now. */ 513 if (esph != NULL) { 514 alen = xform_ah_authsize(esph); 515 AHSTAT_INC(ahs_hist[sav->alg_auth]); 516 if (crp->crp_etype == EBADMSG) { 517 DPRINTF(("%s: authentication hash mismatch for " 518 "packet in SA %s/%08lx\n", __func__, 519 ipsec_address(&saidx->dst, buf, sizeof(buf)), 520 (u_long) ntohl(sav->spi))); 521 ESPSTAT_INC(esps_badauth); 522 error = EACCES; 523 goto bad; 524 } 525 m->m_flags |= M_AUTHIPDGM; 526 /* Remove trailing authenticator */ 527 m_adj(m, -alen); 528 } 529 530 /* Release the crypto descriptors */ 531 free(xd, M_XDATA), xd = NULL; 532 crypto_freereq(crp), crp = NULL; 533 534 /* 535 * Packet is now decrypted. 536 */ 537 m->m_flags |= M_DECRYPTED; 538 539 /* 540 * Update replay sequence number, if appropriate. 541 */ 542 if (sav->replay) { 543 u_int32_t seq; 544 545 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 546 sizeof (seq), (caddr_t) &seq); 547 SECASVAR_LOCK(sav); 548 if (ipsec_updatereplay(ntohl(seq), sav)) { 549 SECASVAR_UNLOCK(sav); 550 DPRINTF(("%s: packet replay check for %s\n", __func__, 551 ipsec_sa2str(sav, buf, sizeof(buf)))); 552 ESPSTAT_INC(esps_replay); 553 error = EACCES; 554 goto bad; 555 } 556 SECASVAR_UNLOCK(sav); 557 } 558 559 /* Determine the ESP header length */ 560 if (sav->flags & SADB_X_EXT_OLD) 561 hlen = sizeof (struct esp) + sav->ivlen; 562 else 563 hlen = sizeof (struct newesp) + sav->ivlen; 564 565 /* Remove the ESP header and IV from the mbuf. */ 566 error = m_striphdr(m, skip, hlen); 567 if (error) { 568 ESPSTAT_INC(esps_hdrops); 569 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 570 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 571 (u_long) ntohl(sav->spi))); 572 goto bad; 573 } 574 575 /* Save the last three bytes of decrypted data */ 576 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 577 578 /* Verify pad length */ 579 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 580 ESPSTAT_INC(esps_badilen); 581 DPRINTF(("%s: invalid padding length %d for %u byte packet " 582 "in SA %s/%08lx\n", __func__, lastthree[1], 583 m->m_pkthdr.len - skip, 584 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 585 (u_long) ntohl(sav->spi))); 586 error = EINVAL; 587 goto bad; 588 } 589 590 /* Verify correct decryption by checking the last padding bytes */ 591 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 592 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 593 ESPSTAT_INC(esps_badenc); 594 DPRINTF(("%s: decryption failed for packet in " 595 "SA %s/%08lx\n", __func__, ipsec_address( 596 &sav->sah->saidx.dst, buf, sizeof(buf)), 597 (u_long) ntohl(sav->spi))); 598 error = EINVAL; 599 goto bad; 600 } 601 } 602 603 /* 604 * RFC4303 2.6: 605 * Silently drop packet if next header field is IPPROTO_NONE. 606 */ 607 if (lastthree[2] == IPPROTO_NONE) 608 goto bad; 609 610 /* Trim the mbuf chain to remove trailing authenticator and padding */ 611 m_adj(m, -(lastthree[1] + 2)); 612 613 /* Restore the Next Protocol field */ 614 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 615 616 switch (saidx->dst.sa.sa_family) { 617 #ifdef INET6 618 case AF_INET6: 619 error = ipsec6_common_input_cb(m, sav, skip, protoff); 620 break; 621 #endif 622 #ifdef INET 623 case AF_INET: 624 error = ipsec4_common_input_cb(m, sav, skip, protoff); 625 break; 626 #endif 627 default: 628 panic("%s: Unexpected address family: %d saidx=%p", __func__, 629 saidx->dst.sa.sa_family, saidx); 630 } 631 CURVNET_RESTORE(); 632 return error; 633 bad: 634 CURVNET_RESTORE(); 635 if (sav != NULL) 636 key_freesav(&sav); 637 if (m != NULL) 638 m_freem(m); 639 if (xd != NULL) 640 free(xd, M_XDATA); 641 if (crp != NULL) 642 crypto_freereq(crp); 643 return error; 644 } 645 /* 646 * ESP output routine, called by ipsec[46]_perform_request(). 647 */ 648 static int 649 esp_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav, 650 u_int idx, int skip, int protoff) 651 { 652 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]); 653 struct cryptop *crp; 654 const struct auth_hash *esph; 655 const struct enc_xform *espx; 656 struct mbuf *mo = NULL; 657 struct xform_data *xd; 658 struct secasindex *saidx; 659 unsigned char *pad; 660 uint8_t *ivp; 661 uint64_t cntr; 662 crypto_session_t cryptoid; 663 int hlen, rlen, padding, blks, alen, i, roff; 664 int error, maxpacketsize; 665 uint8_t prot; 666 667 IPSEC_ASSERT(sav != NULL, ("null SA")); 668 esph = sav->tdb_authalgxform; 669 espx = sav->tdb_encalgxform; 670 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 671 672 if (sav->flags & SADB_X_EXT_OLD) 673 hlen = sizeof (struct esp) + sav->ivlen; 674 else 675 hlen = sizeof (struct newesp) + sav->ivlen; 676 677 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 678 /* 679 * RFC4303 2.4 Requires 4 byte alignment. 680 */ 681 blks = MAX(4, espx->blocksize); /* Cipher blocksize */ 682 683 /* XXX clamp padding length a la KAME??? */ 684 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 685 686 alen = xform_ah_authsize(esph); 687 688 ESPSTAT_INC(esps_output); 689 690 saidx = &sav->sah->saidx; 691 /* Check for maximum packet size violations. */ 692 switch (saidx->dst.sa.sa_family) { 693 #ifdef INET 694 case AF_INET: 695 maxpacketsize = IP_MAXPACKET; 696 break; 697 #endif /* INET */ 698 #ifdef INET6 699 case AF_INET6: 700 maxpacketsize = IPV6_MAXPACKET; 701 break; 702 #endif /* INET6 */ 703 default: 704 DPRINTF(("%s: unknown/unsupported protocol " 705 "family %d, SA %s/%08lx\n", __func__, 706 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst, 707 buf, sizeof(buf)), (u_long) ntohl(sav->spi))); 708 ESPSTAT_INC(esps_nopf); 709 error = EPFNOSUPPORT; 710 goto bad; 711 } 712 /* 713 DPRINTF(("%s: skip %d hlen %d rlen %d padding %d alen %d blksd %d\n", 714 __func__, skip, hlen, rlen, padding, alen, blks)); */ 715 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 716 DPRINTF(("%s: packet in SA %s/%08lx got too big " 717 "(len %u, max len %u)\n", __func__, 718 ipsec_address(&saidx->dst, buf, sizeof(buf)), 719 (u_long) ntohl(sav->spi), 720 skip + hlen + rlen + padding + alen, maxpacketsize)); 721 ESPSTAT_INC(esps_toobig); 722 error = EMSGSIZE; 723 goto bad; 724 } 725 726 /* Update the counters. */ 727 ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip); 728 729 m = m_unshare(m, M_NOWAIT); 730 if (m == NULL) { 731 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 732 ipsec_address(&saidx->dst, buf, sizeof(buf)), 733 (u_long) ntohl(sav->spi))); 734 ESPSTAT_INC(esps_hdrops); 735 error = ENOBUFS; 736 goto bad; 737 } 738 739 /* Inject ESP header. */ 740 mo = m_makespace(m, skip, hlen, &roff); 741 if (mo == NULL) { 742 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 743 __func__, hlen, ipsec_address(&saidx->dst, buf, 744 sizeof(buf)), (u_long) ntohl(sav->spi))); 745 ESPSTAT_INC(esps_hdrops); /* XXX diffs from openbsd */ 746 error = ENOBUFS; 747 goto bad; 748 } 749 750 /* Initialize ESP header. */ 751 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, 752 sizeof(uint32_t)); 753 SECASVAR_LOCK(sav); 754 if (sav->replay) { 755 uint32_t replay; 756 757 #ifdef REGRESSION 758 /* Emulate replay attack when ipsec_replay is TRUE. */ 759 if (!V_ipsec_replay) 760 #endif 761 sav->replay->count++; 762 replay = htonl(sav->replay->count); 763 764 bcopy((caddr_t) &replay, mtod(mo, caddr_t) + roff + 765 sizeof(uint32_t), sizeof(uint32_t)); 766 } 767 cryptoid = sav->tdb_cryptoid; 768 if (SAV_ISCTRORGCM(sav)) 769 cntr = sav->cntr++; 770 SECASVAR_UNLOCK(sav); 771 772 /* 773 * Add padding -- better to do it ourselves than use the crypto engine, 774 * although if/when we support compression, we'd have to do that. 775 */ 776 pad = (u_char *) m_pad(m, padding + alen); 777 if (pad == NULL) { 778 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 779 ipsec_address(&saidx->dst, buf, sizeof(buf)), 780 (u_long) ntohl(sav->spi))); 781 m = NULL; /* NB: free'd by m_pad */ 782 error = ENOBUFS; 783 goto bad; 784 } 785 786 /* 787 * Add padding: random, zero, or self-describing. 788 * XXX catch unexpected setting 789 */ 790 switch (sav->flags & SADB_X_EXT_PMASK) { 791 case SADB_X_EXT_PRAND: 792 arc4random_buf(pad, padding - 2); 793 break; 794 case SADB_X_EXT_PZERO: 795 bzero(pad, padding - 2); 796 break; 797 case SADB_X_EXT_PSEQ: 798 for (i = 0; i < padding - 2; i++) 799 pad[i] = i+1; 800 break; 801 } 802 803 /* Fix padding length and Next Protocol in padding itself. */ 804 pad[padding - 2] = padding - 2; 805 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 806 807 /* Fix Next Protocol in IPv4/IPv6 header. */ 808 prot = IPPROTO_ESP; 809 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 810 811 /* Get crypto descriptor. */ 812 crp = crypto_getreq(cryptoid, M_NOWAIT); 813 if (crp == NULL) { 814 DPRINTF(("%s: failed to acquire crypto descriptor\n", 815 __func__)); 816 ESPSTAT_INC(esps_crypto); 817 error = ENOBUFS; 818 goto bad; 819 } 820 821 /* IPsec-specific opaque crypto info. */ 822 xd = malloc(sizeof(struct xform_data), M_XDATA, M_NOWAIT | M_ZERO); 823 if (xd == NULL) { 824 crypto_freereq(crp); 825 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 826 ESPSTAT_INC(esps_crypto); 827 error = ENOBUFS; 828 goto bad; 829 } 830 831 /* Encryption descriptor. */ 832 crp->crp_payload_start = skip + hlen; 833 crp->crp_payload_length = m->m_pkthdr.len - (skip + hlen + alen); 834 crp->crp_op = CRYPTO_OP_ENCRYPT; 835 836 /* Generate cipher and ESP IVs. */ 837 ivp = &crp->crp_iv[0]; 838 if (SAV_ISCTRORGCM(sav)) { 839 /* 840 * See comment in esp_input() for details on the 841 * cipher IV. A simple per-SA counter stored in 842 * 'cntr' is used as the explicit ESP IV. 843 */ 844 memcpy(ivp, sav->key_enc->key_data + 845 _KEYLEN(sav->key_enc) - 4, 4); 846 be64enc(&ivp[4], cntr); 847 if (SAV_ISCTR(sav)) { 848 be32enc(&ivp[sav->ivlen + 4], 1); 849 } 850 m_copyback(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); 851 crp->crp_flags |= CRYPTO_F_IV_SEPARATE; 852 } else if (sav->ivlen != 0) { 853 arc4rand(ivp, sav->ivlen, 0); 854 crp->crp_iv_start = skip + hlen - sav->ivlen; 855 m_copyback(m, crp->crp_iv_start, sav->ivlen, ivp); 856 } 857 858 /* Callback parameters */ 859 xd->sp = sp; 860 xd->sav = sav; 861 xd->idx = idx; 862 xd->cryptoid = cryptoid; 863 xd->vnet = curvnet; 864 865 /* Crypto operation descriptor. */ 866 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 867 crp->crp_flags |= CRYPTO_F_CBIFSYNC; 868 if (V_async_crypto) 869 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 870 crp->crp_mbuf = m; 871 crp->crp_buf_type = CRYPTO_BUF_MBUF; 872 crp->crp_callback = esp_output_cb; 873 crp->crp_opaque = xd; 874 875 if (esph) { 876 /* Authentication descriptor. */ 877 crp->crp_op |= CRYPTO_OP_COMPUTE_DIGEST; 878 crp->crp_aad_start = skip; 879 if (SAV_ISGCM(sav)) 880 crp->crp_aad_length = 8; /* RFC4106 5, SPI + SN */ 881 else 882 crp->crp_aad_length = hlen; 883 crp->crp_digest_start = m->m_pkthdr.len - alen; 884 } 885 886 return crypto_dispatch(crp); 887 bad: 888 if (m) 889 m_freem(m); 890 key_freesav(&sav); 891 key_freesp(&sp); 892 return (error); 893 } 894 /* 895 * ESP output callback from the crypto driver. 896 */ 897 static int 898 esp_output_cb(struct cryptop *crp) 899 { 900 struct xform_data *xd; 901 struct secpolicy *sp; 902 struct secasvar *sav; 903 struct mbuf *m; 904 crypto_session_t cryptoid; 905 u_int idx; 906 int error; 907 908 xd = (struct xform_data *) crp->crp_opaque; 909 CURVNET_SET(xd->vnet); 910 m = (struct mbuf *) crp->crp_buf; 911 sp = xd->sp; 912 sav = xd->sav; 913 idx = xd->idx; 914 cryptoid = xd->cryptoid; 915 916 /* Check for crypto errors. */ 917 if (crp->crp_etype) { 918 if (crp->crp_etype == EAGAIN) { 919 /* Reset the session ID */ 920 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 921 crypto_freesession(cryptoid); 922 xd->cryptoid = crp->crp_session; 923 CURVNET_RESTORE(); 924 return (crypto_dispatch(crp)); 925 } 926 ESPSTAT_INC(esps_noxform); 927 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 928 error = crp->crp_etype; 929 m_freem(m); 930 goto bad; 931 } 932 933 /* Shouldn't happen... */ 934 if (m == NULL) { 935 ESPSTAT_INC(esps_crypto); 936 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 937 error = EINVAL; 938 goto bad; 939 } 940 free(xd, M_XDATA); 941 crypto_freereq(crp); 942 ESPSTAT_INC(esps_hist[sav->alg_enc]); 943 if (sav->tdb_authalgxform != NULL) 944 AHSTAT_INC(ahs_hist[sav->alg_auth]); 945 946 #ifdef REGRESSION 947 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 948 if (V_ipsec_integrity) { 949 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN]; 950 const struct auth_hash *esph; 951 952 /* 953 * Corrupt HMAC if we want to test integrity verification of 954 * the other side. 955 */ 956 esph = sav->tdb_authalgxform; 957 if (esph != NULL) { 958 int alen; 959 960 alen = xform_ah_authsize(esph); 961 m_copyback(m, m->m_pkthdr.len - alen, 962 alen, ipseczeroes); 963 } 964 } 965 #endif 966 967 /* NB: m is reclaimed by ipsec_process_done. */ 968 error = ipsec_process_done(m, sp, sav, idx); 969 CURVNET_RESTORE(); 970 return (error); 971 bad: 972 CURVNET_RESTORE(); 973 free(xd, M_XDATA); 974 crypto_freereq(crp); 975 key_freesav(&sav); 976 key_freesp(&sp); 977 return (error); 978 } 979 980 static struct xformsw esp_xformsw = { 981 .xf_type = XF_ESP, 982 .xf_name = "IPsec ESP", 983 .xf_init = esp_init, 984 .xf_zeroize = esp_zeroize, 985 .xf_input = esp_input, 986 .xf_output = esp_output, 987 }; 988 989 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 990 xform_attach, &esp_xformsw); 991 SYSUNINIT(esp_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 992 xform_detach, &esp_xformsw); 993