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 #include "opt_ipsec.h" 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/mbuf.h> 45 #include <sys/socket.h> 46 #include <sys/syslog.h> 47 #include <sys/kernel.h> 48 #include <sys/lock.h> 49 #include <sys/random.h> 50 #include <sys/mutex.h> 51 #include <sys/sysctl.h> 52 #include <sys/mutex.h> 53 #include <machine/atomic.h> 54 55 #include <net/if.h> 56 #include <net/vnet.h> 57 58 #include <netinet/in.h> 59 #include <netinet/in_systm.h> 60 #include <netinet/ip.h> 61 #include <netinet/ip_ecn.h> 62 #include <netinet/ip6.h> 63 64 #include <netipsec/ipsec.h> 65 #include <netipsec/ah.h> 66 #include <netipsec/ah_var.h> 67 #include <netipsec/esp.h> 68 #include <netipsec/esp_var.h> 69 #include <netipsec/xform.h> 70 71 #ifdef INET6 72 #include <netinet6/ip6_var.h> 73 #include <netipsec/ipsec6.h> 74 #include <netinet6/ip6_ecn.h> 75 #endif 76 77 #include <netipsec/key.h> 78 #include <netipsec/key_debug.h> 79 80 #include <opencrypto/cryptodev.h> 81 #include <opencrypto/xform.h> 82 83 VNET_DEFINE(int, esp_enable) = 1; 84 VNET_DEFINE_STATIC(int, esp_ctr_compatibility) = 1; 85 #define V_esp_ctr_compatibility VNET(esp_ctr_compatibility) 86 VNET_PCPUSTAT_DEFINE(struct espstat, espstat); 87 VNET_PCPUSTAT_SYSINIT(espstat); 88 89 #ifdef VIMAGE 90 VNET_PCPUSTAT_SYSUNINIT(espstat); 91 #endif /* VIMAGE */ 92 93 SYSCTL_DECL(_net_inet_esp); 94 SYSCTL_INT(_net_inet_esp, OID_AUTO, esp_enable, 95 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(esp_enable), 0, ""); 96 SYSCTL_INT(_net_inet_esp, OID_AUTO, ctr_compatibility, 97 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(esp_ctr_compatibility), 0, 98 "Align AES-CTR encrypted transmitted frames to blocksize"); 99 SYSCTL_VNET_PCPUSTAT(_net_inet_esp, IPSECCTL_STATS, stats, 100 struct espstat, espstat, 101 "ESP statistics (struct espstat, netipsec/esp_var.h"); 102 103 static int esp_input_cb(struct cryptop *op); 104 static int esp_output_cb(struct cryptop *crp); 105 106 size_t 107 esp_hdrsiz(struct secasvar *sav) 108 { 109 size_t size; 110 111 if (sav != NULL) { 112 /*XXX not right for null algorithm--does it matter??*/ 113 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 114 ("SA with null xform")); 115 if (sav->flags & SADB_X_EXT_OLD) 116 size = sizeof (struct esp); 117 else 118 size = sizeof (struct newesp); 119 size += sav->tdb_encalgxform->blocksize + 9; 120 /*XXX need alg check???*/ 121 if (sav->tdb_authalgxform != NULL && sav->replay) 122 size += ah_hdrsiz(sav); 123 } else { 124 /* 125 * base header size 126 * + max iv length for CBC mode 127 * + max pad length 128 * + sizeof (pad length field) 129 * + sizeof (next header field) 130 * + max icv supported. 131 */ 132 size = sizeof (struct newesp) + EALG_MAX_BLOCK_LEN + 9 + 16; 133 } 134 return size; 135 } 136 137 /* 138 * esp_init() is called when an SPI is being set up. 139 */ 140 static int 141 esp_init(struct secasvar *sav, struct xformsw *xsp) 142 { 143 const struct enc_xform *txform; 144 struct crypto_session_params csp; 145 int keylen; 146 int error; 147 148 txform = enc_algorithm_lookup(sav->alg_enc); 149 if (txform == NULL) { 150 DPRINTF(("%s: unsupported encryption algorithm %d\n", 151 __func__, sav->alg_enc)); 152 return EINVAL; 153 } 154 if (sav->key_enc == NULL) { 155 DPRINTF(("%s: no encoding key for %s algorithm\n", 156 __func__, txform->name)); 157 return EINVAL; 158 } 159 if ((sav->flags & (SADB_X_EXT_OLD | SADB_X_EXT_IV4B)) == 160 SADB_X_EXT_IV4B) { 161 DPRINTF(("%s: 4-byte IV not supported with protocol\n", 162 __func__)); 163 return EINVAL; 164 } 165 166 /* subtract off the salt, RFC4106, 8.1 and RFC3686, 5.1 */ 167 keylen = _KEYLEN(sav->key_enc) - SAV_ISCTRORGCM(sav) * 4; 168 if (txform->minkey > keylen || keylen > txform->maxkey) { 169 DPRINTF(("%s: invalid key length %u, must be in the range " 170 "[%u..%u] for algorithm %s\n", __func__, 171 keylen, txform->minkey, txform->maxkey, 172 txform->name)); 173 return EINVAL; 174 } 175 176 if (SAV_ISCTRORGCM(sav)) 177 sav->ivlen = 8; /* RFC4106 3.1 and RFC3686 3.1 */ 178 else 179 sav->ivlen = txform->ivsize; 180 181 memset(&csp, 0, sizeof(csp)); 182 183 /* 184 * Setup AH-related state. 185 */ 186 if (sav->alg_auth != 0) { 187 error = ah_init0(sav, xsp, &csp); 188 if (error) 189 return error; 190 } 191 192 /* NB: override anything set in ah_init0 */ 193 sav->tdb_xform = xsp; 194 sav->tdb_encalgxform = txform; 195 196 /* 197 * Whenever AES-GCM is used for encryption, one 198 * of the AES authentication algorithms is chosen 199 * as well, based on the key size. 200 */ 201 if (sav->alg_enc == SADB_X_EALG_AESGCM16) { 202 switch (keylen) { 203 case AES_128_GMAC_KEY_LEN: 204 sav->alg_auth = SADB_X_AALG_AES128GMAC; 205 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_128; 206 break; 207 case AES_192_GMAC_KEY_LEN: 208 sav->alg_auth = SADB_X_AALG_AES192GMAC; 209 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_192; 210 break; 211 case AES_256_GMAC_KEY_LEN: 212 sav->alg_auth = SADB_X_AALG_AES256GMAC; 213 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_256; 214 break; 215 default: 216 DPRINTF(("%s: invalid key length %u" 217 "for algorithm %s\n", __func__, 218 keylen, txform->name)); 219 return EINVAL; 220 } 221 csp.csp_mode = CSP_MODE_AEAD; 222 } else if (sav->alg_auth != 0) 223 csp.csp_mode = CSP_MODE_ETA; 224 else 225 csp.csp_mode = CSP_MODE_CIPHER; 226 227 /* Initialize crypto session. */ 228 csp.csp_cipher_alg = sav->tdb_encalgxform->type; 229 if (csp.csp_cipher_alg != CRYPTO_NULL_CBC) { 230 csp.csp_cipher_key = sav->key_enc->key_data; 231 csp.csp_cipher_klen = _KEYBITS(sav->key_enc) / 8 - 232 SAV_ISCTRORGCM(sav) * 4; 233 }; 234 csp.csp_ivlen = txform->ivsize; 235 236 error = crypto_newsession(&sav->tdb_cryptoid, &csp, V_crypto_support); 237 return error; 238 } 239 240 /* 241 * Paranoia. 242 */ 243 static int 244 esp_zeroize(struct secasvar *sav) 245 { 246 /* NB: ah_zerorize free's the crypto session state */ 247 int error = ah_zeroize(sav); 248 249 if (sav->key_enc) 250 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc)); 251 sav->tdb_encalgxform = NULL; 252 sav->tdb_xform = NULL; 253 return error; 254 } 255 256 /* 257 * ESP input processing, called (eventually) through the protocol switch. 258 */ 259 static int 260 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 261 { 262 IPSEC_DEBUG_DECLARE(char buf[128]); 263 const struct auth_hash *esph; 264 const struct enc_xform *espx; 265 struct xform_data *xd; 266 struct cryptop *crp; 267 struct newesp *esp; 268 uint8_t *ivp; 269 crypto_session_t cryptoid; 270 int alen, error, hlen, plen; 271 272 IPSEC_ASSERT(sav != NULL, ("null SA")); 273 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); 274 275 error = EINVAL; 276 /* Valid IP Packet length ? */ 277 if ( (skip&3) || (m->m_pkthdr.len&3) ){ 278 DPRINTF(("%s: misaligned packet, skip %u pkt len %u", 279 __func__, skip, m->m_pkthdr.len)); 280 ESPSTAT_INC(esps_badilen); 281 goto bad; 282 } 283 284 if (m->m_len < skip + sizeof(*esp)) { 285 m = m_pullup(m, skip + sizeof(*esp)); 286 if (m == NULL) { 287 DPRINTF(("%s: cannot pullup header\n", __func__)); 288 ESPSTAT_INC(esps_hdrops); /*XXX*/ 289 error = ENOBUFS; 290 goto bad; 291 } 292 } 293 esp = (struct newesp *)(mtod(m, caddr_t) + skip); 294 295 esph = sav->tdb_authalgxform; 296 espx = sav->tdb_encalgxform; 297 298 /* Determine the ESP header and auth length */ 299 if (sav->flags & SADB_X_EXT_OLD) 300 hlen = sizeof (struct esp) + sav->ivlen; 301 else 302 hlen = sizeof (struct newesp) + sav->ivlen; 303 304 alen = xform_ah_authsize(esph); 305 306 /* 307 * Verify payload length is multiple of encryption algorithm 308 * block size. 309 * 310 * NB: This works for the null algorithm because the blocksize 311 * is 4 and all packets must be 4-byte aligned regardless 312 * of the algorithm. 313 */ 314 plen = m->m_pkthdr.len - (skip + hlen + alen); 315 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 316 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 317 " SA %s/%08lx\n", __func__, plen, espx->blocksize, 318 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 319 (u_long)ntohl(sav->spi))); 320 ESPSTAT_INC(esps_badilen); 321 goto bad; 322 } 323 324 /* 325 * Check sequence number. 326 */ 327 SECASVAR_LOCK(sav); 328 if (esph != NULL && sav->replay != NULL && sav->replay->wsize != 0) { 329 if (ipsec_chkreplay(ntohl(esp->esp_seq), sav) == 0) { 330 SECASVAR_UNLOCK(sav); 331 DPRINTF(("%s: packet replay check for %s\n", __func__, 332 ipsec_sa2str(sav, buf, sizeof(buf)))); 333 ESPSTAT_INC(esps_replay); 334 error = EACCES; 335 goto bad; 336 } 337 } 338 cryptoid = sav->tdb_cryptoid; 339 SECASVAR_UNLOCK(sav); 340 341 /* Update the counters */ 342 ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen)); 343 344 /* Get crypto descriptors */ 345 crp = crypto_getreq(cryptoid, M_NOWAIT); 346 if (crp == NULL) { 347 DPRINTF(("%s: failed to acquire crypto descriptors\n", 348 __func__)); 349 ESPSTAT_INC(esps_crypto); 350 error = ENOBUFS; 351 goto bad; 352 } 353 354 /* Get IPsec-specific opaque pointer */ 355 xd = malloc(sizeof(*xd), M_XDATA, M_NOWAIT | M_ZERO); 356 if (xd == NULL) { 357 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 358 ESPSTAT_INC(esps_crypto); 359 crypto_freereq(crp); 360 error = ENOBUFS; 361 goto bad; 362 } 363 364 if (esph != NULL) { 365 crp->crp_op = CRYPTO_OP_VERIFY_DIGEST; 366 crp->crp_aad_start = skip; 367 if (SAV_ISGCM(sav)) 368 crp->crp_aad_length = 8; /* RFC4106 5, SPI + SN */ 369 else 370 crp->crp_aad_length = hlen; 371 crp->crp_digest_start = m->m_pkthdr.len - alen; 372 } 373 374 /* Crypto operation descriptor */ 375 crp->crp_flags = CRYPTO_F_CBIFSYNC; 376 if (V_async_crypto) 377 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 378 crypto_use_mbuf(crp, m); 379 crp->crp_callback = esp_input_cb; 380 crp->crp_opaque = xd; 381 382 /* These are passed as-is to the callback */ 383 xd->sav = sav; 384 xd->protoff = protoff; 385 xd->skip = skip; 386 xd->cryptoid = cryptoid; 387 xd->vnet = curvnet; 388 389 /* Decryption descriptor */ 390 crp->crp_op |= CRYPTO_OP_DECRYPT; 391 crp->crp_payload_start = skip + hlen; 392 crp->crp_payload_length = m->m_pkthdr.len - (skip + hlen + alen); 393 394 /* Generate or read cipher IV. */ 395 if (SAV_ISCTRORGCM(sav)) { 396 ivp = &crp->crp_iv[0]; 397 398 /* 399 * AES-GCM and AES-CTR use similar cipher IV formats 400 * defined in RFC 4106 section 4 and RFC 3686 section 401 * 4, respectively. 402 * 403 * The first 4 bytes of the cipher IV contain an 404 * implicit salt, or nonce, obtained from the last 4 405 * bytes of the encryption key. The next 8 bytes hold 406 * an explicit IV unique to each packet. This 407 * explicit IV is used as the ESP IV for the packet. 408 * The last 4 bytes hold a big-endian block counter 409 * incremented for each block. For AES-GCM, the block 410 * counter's initial value is defined as part of the 411 * algorithm. For AES-CTR, the block counter's 412 * initial value for each packet is defined as 1 by 413 * RFC 3686. 414 * 415 * ------------------------------------------ 416 * | Salt | Explicit ESP IV | Block Counter | 417 * ------------------------------------------ 418 * 4 bytes 8 bytes 4 bytes 419 */ 420 memcpy(ivp, sav->key_enc->key_data + 421 _KEYLEN(sav->key_enc) - 4, 4); 422 m_copydata(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); 423 if (SAV_ISCTR(sav)) { 424 be32enc(&ivp[sav->ivlen + 4], 1); 425 } 426 crp->crp_flags |= CRYPTO_F_IV_SEPARATE; 427 } else if (sav->ivlen != 0) 428 crp->crp_iv_start = skip + hlen - sav->ivlen; 429 430 return (crypto_dispatch(crp)); 431 bad: 432 m_freem(m); 433 key_freesav(&sav); 434 return (error); 435 } 436 437 /* 438 * ESP input callback from the crypto driver. 439 */ 440 static int 441 esp_input_cb(struct cryptop *crp) 442 { 443 IPSEC_DEBUG_DECLARE(char buf[128]); 444 uint8_t lastthree[3]; 445 const struct auth_hash *esph; 446 struct mbuf *m; 447 struct xform_data *xd; 448 struct secasvar *sav; 449 struct secasindex *saidx; 450 crypto_session_t cryptoid; 451 int hlen, skip, protoff, error, alen; 452 453 m = crp->crp_buf.cb_mbuf; 454 xd = crp->crp_opaque; 455 CURVNET_SET(xd->vnet); 456 sav = xd->sav; 457 skip = xd->skip; 458 protoff = xd->protoff; 459 cryptoid = xd->cryptoid; 460 saidx = &sav->sah->saidx; 461 esph = sav->tdb_authalgxform; 462 463 /* Check for crypto errors */ 464 if (crp->crp_etype) { 465 if (crp->crp_etype == EAGAIN) { 466 /* Reset the session ID */ 467 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 468 crypto_freesession(cryptoid); 469 xd->cryptoid = crp->crp_session; 470 CURVNET_RESTORE(); 471 return (crypto_dispatch(crp)); 472 } 473 474 /* EBADMSG indicates authentication failure. */ 475 if (!(crp->crp_etype == EBADMSG && esph != NULL)) { 476 ESPSTAT_INC(esps_noxform); 477 DPRINTF(("%s: crypto error %d\n", __func__, 478 crp->crp_etype)); 479 error = crp->crp_etype; 480 goto bad; 481 } 482 } 483 484 /* Shouldn't happen... */ 485 if (m == NULL) { 486 ESPSTAT_INC(esps_crypto); 487 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 488 error = EINVAL; 489 goto bad; 490 } 491 ESPSTAT_INC(esps_hist[sav->alg_enc]); 492 493 /* If authentication was performed, check now. */ 494 if (esph != NULL) { 495 alen = xform_ah_authsize(esph); 496 AHSTAT_INC(ahs_hist[sav->alg_auth]); 497 if (crp->crp_etype == EBADMSG) { 498 DPRINTF(("%s: authentication hash mismatch for " 499 "packet in SA %s/%08lx\n", __func__, 500 ipsec_address(&saidx->dst, buf, sizeof(buf)), 501 (u_long) ntohl(sav->spi))); 502 ESPSTAT_INC(esps_badauth); 503 error = EACCES; 504 goto bad; 505 } 506 m->m_flags |= M_AUTHIPDGM; 507 /* Remove trailing authenticator */ 508 m_adj(m, -alen); 509 } 510 511 /* Release the crypto descriptors */ 512 free(xd, M_XDATA), xd = NULL; 513 crypto_freereq(crp), crp = NULL; 514 515 /* 516 * Packet is now decrypted. 517 */ 518 m->m_flags |= M_DECRYPTED; 519 520 /* 521 * Update replay sequence number, if appropriate. 522 */ 523 if (sav->replay) { 524 u_int32_t seq; 525 526 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 527 sizeof (seq), (caddr_t) &seq); 528 SECASVAR_LOCK(sav); 529 if (ipsec_updatereplay(ntohl(seq), sav)) { 530 SECASVAR_UNLOCK(sav); 531 DPRINTF(("%s: packet replay check for %s\n", __func__, 532 ipsec_sa2str(sav, buf, sizeof(buf)))); 533 ESPSTAT_INC(esps_replay); 534 error = EACCES; 535 goto bad; 536 } 537 SECASVAR_UNLOCK(sav); 538 } 539 540 /* Determine the ESP header length */ 541 if (sav->flags & SADB_X_EXT_OLD) 542 hlen = sizeof (struct esp) + sav->ivlen; 543 else 544 hlen = sizeof (struct newesp) + sav->ivlen; 545 546 /* Remove the ESP header and IV from the mbuf. */ 547 error = m_striphdr(m, skip, hlen); 548 if (error) { 549 ESPSTAT_INC(esps_hdrops); 550 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 551 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 552 (u_long) ntohl(sav->spi))); 553 goto bad; 554 } 555 556 /* Save the last three bytes of decrypted data */ 557 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 558 559 /* Verify pad length */ 560 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 561 ESPSTAT_INC(esps_badilen); 562 DPRINTF(("%s: invalid padding length %d for %u byte packet " 563 "in SA %s/%08lx\n", __func__, lastthree[1], 564 m->m_pkthdr.len - skip, 565 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 566 (u_long) ntohl(sav->spi))); 567 error = EINVAL; 568 goto bad; 569 } 570 571 /* Verify correct decryption by checking the last padding bytes */ 572 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 573 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 574 ESPSTAT_INC(esps_badenc); 575 DPRINTF(("%s: decryption failed for packet in " 576 "SA %s/%08lx\n", __func__, ipsec_address( 577 &sav->sah->saidx.dst, buf, sizeof(buf)), 578 (u_long) ntohl(sav->spi))); 579 error = EINVAL; 580 goto bad; 581 } 582 } 583 584 /* 585 * RFC4303 2.6: 586 * Silently drop packet if next header field is IPPROTO_NONE. 587 */ 588 if (lastthree[2] == IPPROTO_NONE) 589 goto bad; 590 591 /* Trim the mbuf chain to remove trailing authenticator and padding */ 592 m_adj(m, -(lastthree[1] + 2)); 593 594 /* Restore the Next Protocol field */ 595 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 596 597 switch (saidx->dst.sa.sa_family) { 598 #ifdef INET6 599 case AF_INET6: 600 error = ipsec6_common_input_cb(m, sav, skip, protoff); 601 break; 602 #endif 603 #ifdef INET 604 case AF_INET: 605 error = ipsec4_common_input_cb(m, sav, skip, protoff); 606 break; 607 #endif 608 default: 609 panic("%s: Unexpected address family: %d saidx=%p", __func__, 610 saidx->dst.sa.sa_family, saidx); 611 } 612 CURVNET_RESTORE(); 613 return error; 614 bad: 615 CURVNET_RESTORE(); 616 if (sav != NULL) 617 key_freesav(&sav); 618 if (m != NULL) 619 m_freem(m); 620 if (xd != NULL) 621 free(xd, M_XDATA); 622 if (crp != NULL) 623 crypto_freereq(crp); 624 return error; 625 } 626 /* 627 * ESP output routine, called by ipsec[46]_perform_request(). 628 */ 629 static int 630 esp_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav, 631 u_int idx, int skip, int protoff) 632 { 633 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]); 634 struct cryptop *crp; 635 const struct auth_hash *esph; 636 const struct enc_xform *espx; 637 struct mbuf *mo = NULL; 638 struct xform_data *xd; 639 struct secasindex *saidx; 640 unsigned char *pad; 641 uint8_t *ivp; 642 uint64_t cntr; 643 crypto_session_t cryptoid; 644 int hlen, rlen, padding, blks, alen, i, roff; 645 int error, maxpacketsize; 646 uint8_t prot; 647 648 IPSEC_ASSERT(sav != NULL, ("null SA")); 649 esph = sav->tdb_authalgxform; 650 espx = sav->tdb_encalgxform; 651 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 652 653 if (sav->flags & SADB_X_EXT_OLD) 654 hlen = sizeof (struct esp) + sav->ivlen; 655 else 656 hlen = sizeof (struct newesp) + sav->ivlen; 657 658 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 659 /* 660 * RFC4303 2.4 Requires 4 byte alignment. 661 * Old versions of FreeBSD can't decrypt partial blocks encrypted 662 * with AES-CTR. Align payload to native_blocksize (16 bytes) 663 * in order to preserve compatibility. 664 */ 665 if (SAV_ISCTR(sav) && V_esp_ctr_compatibility) 666 blks = MAX(4, espx->native_blocksize); /* Cipher blocksize */ 667 else 668 blks = MAX(4, espx->blocksize); 669 670 /* XXX clamp padding length a la KAME??? */ 671 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 672 673 alen = xform_ah_authsize(esph); 674 675 ESPSTAT_INC(esps_output); 676 677 saidx = &sav->sah->saidx; 678 /* Check for maximum packet size violations. */ 679 switch (saidx->dst.sa.sa_family) { 680 #ifdef INET 681 case AF_INET: 682 maxpacketsize = IP_MAXPACKET; 683 break; 684 #endif /* INET */ 685 #ifdef INET6 686 case AF_INET6: 687 maxpacketsize = IPV6_MAXPACKET; 688 break; 689 #endif /* INET6 */ 690 default: 691 DPRINTF(("%s: unknown/unsupported protocol " 692 "family %d, SA %s/%08lx\n", __func__, 693 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst, 694 buf, sizeof(buf)), (u_long) ntohl(sav->spi))); 695 ESPSTAT_INC(esps_nopf); 696 error = EPFNOSUPPORT; 697 goto bad; 698 } 699 /* 700 DPRINTF(("%s: skip %d hlen %d rlen %d padding %d alen %d blksd %d\n", 701 __func__, skip, hlen, rlen, padding, alen, blks)); */ 702 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 703 DPRINTF(("%s: packet in SA %s/%08lx got too big " 704 "(len %u, max len %u)\n", __func__, 705 ipsec_address(&saidx->dst, buf, sizeof(buf)), 706 (u_long) ntohl(sav->spi), 707 skip + hlen + rlen + padding + alen, maxpacketsize)); 708 ESPSTAT_INC(esps_toobig); 709 error = EMSGSIZE; 710 goto bad; 711 } 712 713 /* Update the counters. */ 714 ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip); 715 716 m = m_unshare(m, M_NOWAIT); 717 if (m == NULL) { 718 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 719 ipsec_address(&saidx->dst, buf, sizeof(buf)), 720 (u_long) ntohl(sav->spi))); 721 ESPSTAT_INC(esps_hdrops); 722 error = ENOBUFS; 723 goto bad; 724 } 725 726 /* Inject ESP header. */ 727 mo = m_makespace(m, skip, hlen, &roff); 728 if (mo == NULL) { 729 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 730 __func__, hlen, ipsec_address(&saidx->dst, buf, 731 sizeof(buf)), (u_long) ntohl(sav->spi))); 732 ESPSTAT_INC(esps_hdrops); /* XXX diffs from openbsd */ 733 error = ENOBUFS; 734 goto bad; 735 } 736 737 /* Initialize ESP header. */ 738 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, 739 sizeof(uint32_t)); 740 SECASVAR_LOCK(sav); 741 if (sav->replay) { 742 uint32_t replay; 743 744 #ifdef REGRESSION 745 /* Emulate replay attack when ipsec_replay is TRUE. */ 746 if (!V_ipsec_replay) 747 #endif 748 sav->replay->count++; 749 replay = htonl(sav->replay->count); 750 751 bcopy((caddr_t) &replay, mtod(mo, caddr_t) + roff + 752 sizeof(uint32_t), sizeof(uint32_t)); 753 } 754 cryptoid = sav->tdb_cryptoid; 755 if (SAV_ISCTRORGCM(sav)) 756 cntr = sav->cntr++; 757 SECASVAR_UNLOCK(sav); 758 759 /* 760 * Add padding -- better to do it ourselves than use the crypto engine, 761 * although if/when we support compression, we'd have to do that. 762 */ 763 pad = (u_char *) m_pad(m, padding + alen); 764 if (pad == NULL) { 765 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 766 ipsec_address(&saidx->dst, buf, sizeof(buf)), 767 (u_long) ntohl(sav->spi))); 768 m = NULL; /* NB: free'd by m_pad */ 769 error = ENOBUFS; 770 goto bad; 771 } 772 773 /* 774 * Add padding: random, zero, or self-describing. 775 * XXX catch unexpected setting 776 */ 777 switch (sav->flags & SADB_X_EXT_PMASK) { 778 case SADB_X_EXT_PRAND: 779 arc4random_buf(pad, padding - 2); 780 break; 781 case SADB_X_EXT_PZERO: 782 bzero(pad, padding - 2); 783 break; 784 case SADB_X_EXT_PSEQ: 785 for (i = 0; i < padding - 2; i++) 786 pad[i] = i+1; 787 break; 788 } 789 790 /* Fix padding length and Next Protocol in padding itself. */ 791 pad[padding - 2] = padding - 2; 792 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 793 794 /* Fix Next Protocol in IPv4/IPv6 header. */ 795 prot = IPPROTO_ESP; 796 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 797 798 /* Get crypto descriptor. */ 799 crp = crypto_getreq(cryptoid, M_NOWAIT); 800 if (crp == NULL) { 801 DPRINTF(("%s: failed to acquire crypto descriptor\n", 802 __func__)); 803 ESPSTAT_INC(esps_crypto); 804 error = ENOBUFS; 805 goto bad; 806 } 807 808 /* IPsec-specific opaque crypto info. */ 809 xd = malloc(sizeof(struct xform_data), M_XDATA, M_NOWAIT | M_ZERO); 810 if (xd == NULL) { 811 crypto_freereq(crp); 812 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 813 ESPSTAT_INC(esps_crypto); 814 error = ENOBUFS; 815 goto bad; 816 } 817 818 /* Encryption descriptor. */ 819 crp->crp_payload_start = skip + hlen; 820 crp->crp_payload_length = m->m_pkthdr.len - (skip + hlen + alen); 821 crp->crp_op = CRYPTO_OP_ENCRYPT; 822 823 /* Generate cipher and ESP IVs. */ 824 ivp = &crp->crp_iv[0]; 825 if (SAV_ISCTRORGCM(sav)) { 826 /* 827 * See comment in esp_input() for details on the 828 * cipher IV. A simple per-SA counter stored in 829 * 'cntr' is used as the explicit ESP IV. 830 */ 831 memcpy(ivp, sav->key_enc->key_data + 832 _KEYLEN(sav->key_enc) - 4, 4); 833 be64enc(&ivp[4], cntr); 834 if (SAV_ISCTR(sav)) { 835 be32enc(&ivp[sav->ivlen + 4], 1); 836 } 837 m_copyback(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); 838 crp->crp_flags |= CRYPTO_F_IV_SEPARATE; 839 } else if (sav->ivlen != 0) { 840 arc4rand(ivp, sav->ivlen, 0); 841 crp->crp_iv_start = skip + hlen - sav->ivlen; 842 m_copyback(m, crp->crp_iv_start, sav->ivlen, ivp); 843 } 844 845 /* Callback parameters */ 846 xd->sp = sp; 847 xd->sav = sav; 848 xd->idx = idx; 849 xd->cryptoid = cryptoid; 850 xd->vnet = curvnet; 851 852 /* Crypto operation descriptor. */ 853 crp->crp_flags |= CRYPTO_F_CBIFSYNC; 854 if (V_async_crypto) 855 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 856 crypto_use_mbuf(crp, m); 857 crp->crp_callback = esp_output_cb; 858 crp->crp_opaque = xd; 859 860 if (esph) { 861 /* Authentication descriptor. */ 862 crp->crp_op |= CRYPTO_OP_COMPUTE_DIGEST; 863 crp->crp_aad_start = skip; 864 if (SAV_ISGCM(sav)) 865 crp->crp_aad_length = 8; /* RFC4106 5, SPI + SN */ 866 else 867 crp->crp_aad_length = hlen; 868 crp->crp_digest_start = m->m_pkthdr.len - alen; 869 } 870 871 return crypto_dispatch(crp); 872 bad: 873 if (m) 874 m_freem(m); 875 key_freesav(&sav); 876 key_freesp(&sp); 877 return (error); 878 } 879 /* 880 * ESP output callback from the crypto driver. 881 */ 882 static int 883 esp_output_cb(struct cryptop *crp) 884 { 885 struct xform_data *xd; 886 struct secpolicy *sp; 887 struct secasvar *sav; 888 struct mbuf *m; 889 crypto_session_t cryptoid; 890 u_int idx; 891 int error; 892 893 xd = (struct xform_data *) crp->crp_opaque; 894 CURVNET_SET(xd->vnet); 895 m = crp->crp_buf.cb_mbuf; 896 sp = xd->sp; 897 sav = xd->sav; 898 idx = xd->idx; 899 cryptoid = xd->cryptoid; 900 901 /* Check for crypto errors. */ 902 if (crp->crp_etype) { 903 if (crp->crp_etype == EAGAIN) { 904 /* Reset the session ID */ 905 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 906 crypto_freesession(cryptoid); 907 xd->cryptoid = crp->crp_session; 908 CURVNET_RESTORE(); 909 return (crypto_dispatch(crp)); 910 } 911 ESPSTAT_INC(esps_noxform); 912 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 913 error = crp->crp_etype; 914 m_freem(m); 915 goto bad; 916 } 917 918 /* Shouldn't happen... */ 919 if (m == NULL) { 920 ESPSTAT_INC(esps_crypto); 921 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 922 error = EINVAL; 923 goto bad; 924 } 925 free(xd, M_XDATA); 926 crypto_freereq(crp); 927 ESPSTAT_INC(esps_hist[sav->alg_enc]); 928 if (sav->tdb_authalgxform != NULL) 929 AHSTAT_INC(ahs_hist[sav->alg_auth]); 930 931 #ifdef REGRESSION 932 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 933 if (V_ipsec_integrity) { 934 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN]; 935 const struct auth_hash *esph; 936 937 /* 938 * Corrupt HMAC if we want to test integrity verification of 939 * the other side. 940 */ 941 esph = sav->tdb_authalgxform; 942 if (esph != NULL) { 943 int alen; 944 945 alen = xform_ah_authsize(esph); 946 m_copyback(m, m->m_pkthdr.len - alen, 947 alen, ipseczeroes); 948 } 949 } 950 #endif 951 952 /* NB: m is reclaimed by ipsec_process_done. */ 953 error = ipsec_process_done(m, sp, sav, idx); 954 CURVNET_RESTORE(); 955 return (error); 956 bad: 957 CURVNET_RESTORE(); 958 free(xd, M_XDATA); 959 crypto_freereq(crp); 960 key_freesav(&sav); 961 key_freesp(&sp); 962 return (error); 963 } 964 965 static struct xformsw esp_xformsw = { 966 .xf_type = XF_ESP, 967 .xf_name = "IPsec ESP", 968 .xf_init = esp_init, 969 .xf_zeroize = esp_zeroize, 970 .xf_input = esp_input, 971 .xf_output = esp_output, 972 }; 973 974 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 975 xform_attach, &esp_xformsw); 976 SYSUNINIT(esp_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 977 xform_detach, &esp_xformsw); 978