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#define SPI_SIZE 4 84 85VNET_DEFINE(int, esp_enable) = 1; 86VNET_DEFINE_STATIC(int, esp_ctr_compatibility) = 1; 87#define V_esp_ctr_compatibility VNET(esp_ctr_compatibility) 88VNET_PCPUSTAT_DEFINE(struct espstat, espstat); 89VNET_PCPUSTAT_SYSINIT(espstat); 90 91#ifdef VIMAGE 92VNET_PCPUSTAT_SYSUNINIT(espstat); 93#endif /* VIMAGE */ 94 95SYSCTL_DECL(_net_inet_esp); 96SYSCTL_INT(_net_inet_esp, OID_AUTO, esp_enable, 97 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(esp_enable), 0, ""); 98SYSCTL_INT(_net_inet_esp, OID_AUTO, ctr_compatibility, 99 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(esp_ctr_compatibility), 0, 100 "Align AES-CTR encrypted transmitted frames to blocksize"); 101SYSCTL_VNET_PCPUSTAT(_net_inet_esp, IPSECCTL_STATS, stats, 102 struct espstat, espstat, 103 "ESP statistics (struct espstat, netipsec/esp_var.h"); 104 105static int esp_input_cb(struct cryptop *op); 106static int esp_output_cb(struct cryptop *crp); 107 108size_t 109esp_hdrsiz(struct secasvar *sav) 110{ 111 size_t size; 112 113 if (sav != NULL) { 114 /*XXX not right for null algorithm--does it matter??*/ 115 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, 116 ("SA with null xform")); 117 if (sav->flags & SADB_X_EXT_OLD) 118 size = sizeof (struct esp); 119 else 120 size = sizeof (struct newesp); 121 size += sav->tdb_encalgxform->blocksize + 9; 122 /*XXX need alg check???*/ 123 if (sav->tdb_authalgxform != NULL && sav->replay) 124 size += ah_hdrsiz(sav); 125 } else { 126 /* 127 * base header size 128 * + max iv length for CBC mode 129 * + max pad length 130 * + sizeof (pad length field) 131 * + sizeof (next header field) 132 * + max icv supported. 133 */ 134 size = sizeof (struct newesp) + EALG_MAX_BLOCK_LEN + 9 + 16; 135 } 136 return size; 137} 138 139/* 140 * esp_init() is called when an SPI is being set up. 141 */ 142static int 143esp_init(struct secasvar *sav, struct xformsw *xsp) 144{ 145 const struct enc_xform *txform; 146 struct crypto_session_params csp; 147 int keylen; 148 int error; 149 150 txform = enc_algorithm_lookup(sav->alg_enc); 151 if (txform == NULL) { 152 DPRINTF(("%s: unsupported encryption algorithm %d\n", 153 __func__, sav->alg_enc)); 154 return EINVAL; 155 } 156 if (sav->key_enc == NULL) { 157 DPRINTF(("%s: no encoding key for %s algorithm\n", 158 __func__, txform->name)); 159 return EINVAL; 160 } 161 if ((sav->flags & (SADB_X_EXT_OLD | SADB_X_EXT_IV4B)) == 162 SADB_X_EXT_IV4B) { 163 DPRINTF(("%s: 4-byte IV not supported with protocol\n", 164 __func__)); 165 return EINVAL; 166 } 167 168 /* subtract off the salt, RFC4106, 8.1 and RFC3686, 5.1 */ 169 keylen = _KEYLEN(sav->key_enc) - SAV_ISCTRORGCM(sav) * 4; 170 if (txform->minkey > keylen || keylen > txform->maxkey) { 171 DPRINTF(("%s: invalid key length %u, must be in the range " 172 "[%u..%u] for algorithm %s\n", __func__, 173 keylen, txform->minkey, txform->maxkey, 174 txform->name)); 175 return EINVAL; 176 } 177 178 if (SAV_ISCTRORGCM(sav)) 179 sav->ivlen = 8; /* RFC4106 3.1 and RFC3686 3.1 */ 180 else 181 sav->ivlen = txform->ivsize; 182 183 memset(&csp, 0, sizeof(csp)); 184 185 /* 186 * Setup AH-related state. 187 */ 188 if (sav->alg_auth != 0) { 189 error = ah_init0(sav, xsp, &csp); 190 if (error) 191 return error; 192 } 193 194 /* NB: override anything set in ah_init0 */ 195 sav->tdb_xform = xsp; 196 sav->tdb_encalgxform = txform; 197 198 /* 199 * Whenever AES-GCM is used for encryption, one 200 * of the AES authentication algorithms is chosen 201 * as well, based on the key size. 202 */ 203 if (sav->alg_enc == SADB_X_EALG_AESGCM16) { 204 switch (keylen) { 205 case AES_128_GMAC_KEY_LEN: 206 sav->alg_auth = SADB_X_AALG_AES128GMAC; 207 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_128; 208 break; 209 case AES_192_GMAC_KEY_LEN: 210 sav->alg_auth = SADB_X_AALG_AES192GMAC; 211 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_192; 212 break; 213 case AES_256_GMAC_KEY_LEN: 214 sav->alg_auth = SADB_X_AALG_AES256GMAC; 215 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_256; 216 break; 217 default: 218 DPRINTF(("%s: invalid key length %u" 219 "for algorithm %s\n", __func__, 220 keylen, txform->name)); 221 return EINVAL; 222 } 223 csp.csp_mode = CSP_MODE_AEAD; 224 if (sav->flags & SADB_X_SAFLAGS_ESN) 225 csp.csp_flags |= CSP_F_SEPARATE_AAD; 226 } else if (sav->alg_auth != 0) { 227 csp.csp_mode = CSP_MODE_ETA; 228 if (sav->flags & SADB_X_SAFLAGS_ESN) 229 csp.csp_flags |= CSP_F_ESN; 230 } else 231 csp.csp_mode = CSP_MODE_CIPHER; 232 233 /* Initialize crypto session. */ 234 csp.csp_cipher_alg = sav->tdb_encalgxform->type; 235 if (csp.csp_cipher_alg != CRYPTO_NULL_CBC) { 236 csp.csp_cipher_key = sav->key_enc->key_data; 237 csp.csp_cipher_klen = _KEYBITS(sav->key_enc) / 8 - 238 SAV_ISCTRORGCM(sav) * 4; 239 }; 240 csp.csp_ivlen = txform->ivsize; 241 242 error = crypto_newsession(&sav->tdb_cryptoid, &csp, V_crypto_support); 243 return error; 244} 245 246static void 247esp_cleanup(struct secasvar *sav) 248{ 249 250 crypto_freesession(sav->tdb_cryptoid); 251 sav->tdb_cryptoid = NULL; 252 sav->tdb_authalgxform = NULL; 253 sav->tdb_encalgxform = NULL; 254} 255 256/* 257 * ESP input processing, called (eventually) through the protocol switch. 258 */ 259static int 260esp_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 uint32_t seqh; 272 const struct crypto_session_params *csp; 273 274 IPSEC_ASSERT(sav != NULL, ("null SA")); 275 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); 276 277 error = EINVAL; 278 /* Valid IP Packet length ? */ 279 if ( (skip&3) || (m->m_pkthdr.len&3) ){ 280 DPRINTF(("%s: misaligned packet, skip %u pkt len %u", 281 __func__, skip, m->m_pkthdr.len)); 282 ESPSTAT_INC(esps_badilen); 283 goto bad; 284 } 285 286 if (m->m_len < skip + sizeof(*esp)) { 287 m = m_pullup(m, skip + sizeof(*esp)); 288 if (m == NULL) { 289 DPRINTF(("%s: cannot pullup header\n", __func__)); 290 ESPSTAT_INC(esps_hdrops); /*XXX*/ 291 error = ENOBUFS; 292 goto bad; 293 } 294 } 295 esp = (struct newesp *)(mtod(m, caddr_t) + skip); 296 297 esph = sav->tdb_authalgxform; 298 espx = sav->tdb_encalgxform; 299 300 /* Determine the ESP header and auth length */ 301 if (sav->flags & SADB_X_EXT_OLD) 302 hlen = sizeof (struct esp) + sav->ivlen; 303 else 304 hlen = sizeof (struct newesp) + sav->ivlen; 305 306 alen = xform_ah_authsize(esph); 307 308 /* 309 * Verify payload length is multiple of encryption algorithm 310 * block size. 311 * 312 * NB: This works for the null algorithm because the blocksize 313 * is 4 and all packets must be 4-byte aligned regardless 314 * of the algorithm. 315 */ 316 plen = m->m_pkthdr.len - (skip + hlen + alen); 317 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { 318 DPRINTF(("%s: payload of %d octets not a multiple of %d octets," 319 " SA %s/%08lx\n", __func__, plen, espx->blocksize, 320 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 321 (u_long)ntohl(sav->spi))); 322 ESPSTAT_INC(esps_badilen); 323 goto bad; 324 } 325 326 /* 327 * Check sequence number. 328 */ 329 SECASVAR_LOCK(sav); 330 if (esph != NULL && sav->replay != NULL && sav->replay->wsize != 0) { 331 if (ipsec_chkreplay(ntohl(esp->esp_seq), &seqh, sav) == 0) { 332 SECASVAR_UNLOCK(sav); 333 DPRINTF(("%s: packet replay check for %s\n", __func__, 334 ipsec_sa2str(sav, buf, sizeof(buf)))); 335 ESPSTAT_INC(esps_replay); 336 error = EACCES; 337 goto bad; 338 } 339 seqh = htonl(seqh); 340 } 341 cryptoid = sav->tdb_cryptoid; 342 SECASVAR_UNLOCK(sav); 343 344 /* Update the counters */ 345 ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen)); 346 347 /* Get crypto descriptors */ 348 crp = crypto_getreq(cryptoid, M_NOWAIT); 349 if (crp == NULL) { 350 DPRINTF(("%s: failed to acquire crypto descriptors\n", 351 __func__)); 352 ESPSTAT_INC(esps_crypto); 353 error = ENOBUFS; 354 goto bad; 355 } 356 357 /* Get IPsec-specific opaque pointer */ 358 xd = malloc(sizeof(*xd), M_XDATA, M_NOWAIT | M_ZERO); 359 if (xd == NULL) { 360 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 361 goto xd_fail; 362 } 363 364 if (esph != NULL) { 365 crp->crp_op = CRYPTO_OP_VERIFY_DIGEST; 366 if (SAV_ISGCM(sav)) 367 crp->crp_aad_length = 8; /* RFC4106 5, SPI + SN */ 368 else 369 crp->crp_aad_length = hlen; 370 371 csp = crypto_get_params(crp->crp_session); 372 if ((csp->csp_flags & CSP_F_SEPARATE_AAD) && 373 (sav->replay != NULL) && (sav->replay->wsize != 0)) { 374 int aad_skip; 375 376 crp->crp_aad_length += sizeof(seqh); 377 crp->crp_aad = malloc(crp->crp_aad_length, M_XDATA, M_NOWAIT); 378 if (crp->crp_aad == NULL) { 379 DPRINTF(("%s: failed to allocate xform_data\n", 380 __func__)); 381 goto crp_aad_fail; 382 } 383 384 /* SPI */ 385 m_copydata(m, skip, SPI_SIZE, crp->crp_aad); 386 aad_skip = SPI_SIZE; 387 388 /* ESN */ 389 bcopy(&seqh, (char *)crp->crp_aad + aad_skip, sizeof(seqh)); 390 aad_skip += sizeof(seqh); 391 392 /* Rest of aad */ 393 if (crp->crp_aad_length - aad_skip > 0) 394 m_copydata(m, skip + SPI_SIZE, 395 crp->crp_aad_length - aad_skip, 396 (char *)crp->crp_aad + aad_skip); 397 } else 398 crp->crp_aad_start = skip; 399 400 if (csp->csp_flags & CSP_F_ESN && 401 sav->replay != NULL && sav->replay->wsize != 0) 402 memcpy(crp->crp_esn, &seqh, sizeof(seqh)); 403 404 crp->crp_digest_start = m->m_pkthdr.len - alen; 405 } 406 407 /* Crypto operation descriptor */ 408 crp->crp_flags = CRYPTO_F_CBIFSYNC; 409 if (V_async_crypto) 410 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 411 crypto_use_mbuf(crp, m); 412 crp->crp_callback = esp_input_cb; 413 crp->crp_opaque = xd; 414 415 /* These are passed as-is to the callback */ 416 xd->sav = sav; 417 xd->protoff = protoff; 418 xd->skip = skip; 419 xd->cryptoid = cryptoid; 420 xd->vnet = curvnet; 421 422 /* Decryption descriptor */ 423 crp->crp_op |= CRYPTO_OP_DECRYPT; 424 crp->crp_payload_start = skip + hlen; 425 crp->crp_payload_length = m->m_pkthdr.len - (skip + hlen + alen); 426 427 /* Generate or read cipher IV. */ 428 if (SAV_ISCTRORGCM(sav)) { 429 ivp = &crp->crp_iv[0]; 430 431 /* 432 * AES-GCM and AES-CTR use similar cipher IV formats 433 * defined in RFC 4106 section 4 and RFC 3686 section 434 * 4, respectively. 435 * 436 * The first 4 bytes of the cipher IV contain an 437 * implicit salt, or nonce, obtained from the last 4 438 * bytes of the encryption key. The next 8 bytes hold 439 * an explicit IV unique to each packet. This 440 * explicit IV is used as the ESP IV for the packet. 441 * The last 4 bytes hold a big-endian block counter 442 * incremented for each block. For AES-GCM, the block 443 * counter's initial value is defined as part of the 444 * algorithm. For AES-CTR, the block counter's 445 * initial value for each packet is defined as 1 by 446 * RFC 3686. 447 * 448 * ------------------------------------------ 449 * | Salt | Explicit ESP IV | Block Counter | 450 * ------------------------------------------ 451 * 4 bytes 8 bytes 4 bytes 452 */ 453 memcpy(ivp, sav->key_enc->key_data + 454 _KEYLEN(sav->key_enc) - 4, 4); 455 m_copydata(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); 456 if (SAV_ISCTR(sav)) { 457 be32enc(&ivp[sav->ivlen + 4], 1); 458 } 459 crp->crp_flags |= CRYPTO_F_IV_SEPARATE; 460 } else if (sav->ivlen != 0) 461 crp->crp_iv_start = skip + hlen - sav->ivlen; 462 463 return (crypto_dispatch(crp)); 464 465crp_aad_fail: 466 free(xd, M_XDATA); 467xd_fail: 468 crypto_freereq(crp); 469 ESPSTAT_INC(esps_crypto); 470 error = ENOBUFS; 471bad: 472 m_freem(m); 473 key_freesav(&sav); 474 return (error); 475} 476 477/* 478 * ESP input callback from the crypto driver. 479 */ 480static int 481esp_input_cb(struct cryptop *crp) 482{ 483 IPSEC_DEBUG_DECLARE(char buf[128]); 484 uint8_t lastthree[3]; 485 const struct auth_hash *esph; 486 struct mbuf *m; 487 struct xform_data *xd; 488 struct secasvar *sav; 489 struct secasindex *saidx; 490 crypto_session_t cryptoid; 491 int hlen, skip, protoff, error, alen; 492 493 m = crp->crp_buf.cb_mbuf; 494 xd = crp->crp_opaque; 495 CURVNET_SET(xd->vnet); 496 sav = xd->sav; 497 skip = xd->skip; 498 protoff = xd->protoff; 499 cryptoid = xd->cryptoid; 500 saidx = &sav->sah->saidx; 501 esph = sav->tdb_authalgxform; 502 503 /* Check for crypto errors */ 504 if (crp->crp_etype) { 505 if (crp->crp_etype == EAGAIN) { 506 /* Reset the session ID */ 507 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 508 crypto_freesession(cryptoid); 509 xd->cryptoid = crp->crp_session; 510 CURVNET_RESTORE(); 511 return (crypto_dispatch(crp)); 512 } 513 514 /* EBADMSG indicates authentication failure. */ 515 if (!(crp->crp_etype == EBADMSG && esph != NULL)) { 516 ESPSTAT_INC(esps_noxform); 517 DPRINTF(("%s: crypto error %d\n", __func__, 518 crp->crp_etype)); 519 error = crp->crp_etype; 520 goto bad; 521 } 522 } 523 524 /* Shouldn't happen... */ 525 if (m == NULL) { 526 ESPSTAT_INC(esps_crypto); 527 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 528 error = EINVAL; 529 goto bad; 530 } 531 ESPSTAT_INC(esps_hist[sav->alg_enc]); 532 533 /* If authentication was performed, check now. */ 534 if (esph != NULL) { 535 alen = xform_ah_authsize(esph); 536 AHSTAT_INC(ahs_hist[sav->alg_auth]); 537 if (crp->crp_etype == EBADMSG) { 538 DPRINTF(("%s: authentication hash mismatch for " 539 "packet in SA %s/%08lx\n", __func__, 540 ipsec_address(&saidx->dst, buf, sizeof(buf)), 541 (u_long) ntohl(sav->spi))); 542 ESPSTAT_INC(esps_badauth); 543 error = EACCES; 544 goto bad; 545 } 546 m->m_flags |= M_AUTHIPDGM; 547 /* Remove trailing authenticator */ 548 m_adj(m, -alen); 549 } 550 551 /* Release the crypto descriptors */ 552 free(xd, M_XDATA), xd = NULL; 553 free(crp->crp_aad, M_XDATA), crp->crp_aad = NULL; 554 crypto_freereq(crp), crp = NULL; 555 556 /* 557 * Packet is now decrypted. 558 */ 559 m->m_flags |= M_DECRYPTED; 560 561 /* 562 * Update replay sequence number, if appropriate. 563 */ 564 if (sav->replay) { 565 u_int32_t seq; 566 567 m_copydata(m, skip + offsetof(struct newesp, esp_seq), 568 sizeof (seq), (caddr_t) &seq); 569 SECASVAR_LOCK(sav); 570 if (ipsec_updatereplay(ntohl(seq), sav)) { 571 SECASVAR_UNLOCK(sav); 572 DPRINTF(("%s: packet replay check for %s\n", __func__, 573 ipsec_sa2str(sav, buf, sizeof(buf)))); 574 ESPSTAT_INC(esps_replay); 575 error = EACCES; 576 goto bad; 577 } 578 SECASVAR_UNLOCK(sav); 579 } 580 581 /* Determine the ESP header length */ 582 if (sav->flags & SADB_X_EXT_OLD) 583 hlen = sizeof (struct esp) + sav->ivlen; 584 else 585 hlen = sizeof (struct newesp) + sav->ivlen; 586 587 /* Remove the ESP header and IV from the mbuf. */ 588 error = m_striphdr(m, skip, hlen); 589 if (error) { 590 ESPSTAT_INC(esps_hdrops); 591 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, 592 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 593 (u_long) ntohl(sav->spi))); 594 goto bad; 595 } 596 597 /* Save the last three bytes of decrypted data */ 598 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 599 600 /* Verify pad length */ 601 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 602 ESPSTAT_INC(esps_badilen); 603 DPRINTF(("%s: invalid padding length %d for %u byte packet " 604 "in SA %s/%08lx\n", __func__, lastthree[1], 605 m->m_pkthdr.len - skip, 606 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 607 (u_long) ntohl(sav->spi))); 608 error = EINVAL; 609 goto bad; 610 } 611 612 /* Verify correct decryption by checking the last padding bytes */ 613 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { 614 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { 615 ESPSTAT_INC(esps_badenc); 616 DPRINTF(("%s: decryption failed for packet in " 617 "SA %s/%08lx\n", __func__, ipsec_address( 618 &sav->sah->saidx.dst, buf, sizeof(buf)), 619 (u_long) ntohl(sav->spi))); 620 error = EINVAL; 621 goto bad; 622 } 623 } 624 625 /* 626 * RFC4303 2.6: 627 * Silently drop packet if next header field is IPPROTO_NONE. 628 */ 629 if (lastthree[2] == IPPROTO_NONE) 630 goto bad; 631 632 /* Trim the mbuf chain to remove trailing authenticator and padding */ 633 m_adj(m, -(lastthree[1] + 2)); 634 635 /* Restore the Next Protocol field */ 636 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2); 637 638 switch (saidx->dst.sa.sa_family) { 639#ifdef INET6 640 case AF_INET6: 641 error = ipsec6_common_input_cb(m, sav, skip, protoff); 642 break; 643#endif 644#ifdef INET 645 case AF_INET: 646 error = ipsec4_common_input_cb(m, sav, skip, protoff); 647 break; 648#endif 649 default: 650 panic("%s: Unexpected address family: %d saidx=%p", __func__, 651 saidx->dst.sa.sa_family, saidx); 652 } 653 CURVNET_RESTORE(); 654 return error; 655bad: 656 CURVNET_RESTORE(); 657 if (sav != NULL) 658 key_freesav(&sav); 659 if (m != NULL) 660 m_freem(m); 661 if (xd != NULL) 662 free(xd, M_XDATA); 663 if (crp != NULL) { 664 free(crp->crp_aad, M_XDATA); 665 crypto_freereq(crp); 666 } 667 return error; 668} 669/* 670 * ESP output routine, called by ipsec[46]_perform_request(). 671 */ 672static int 673esp_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav, 674 u_int idx, int skip, int protoff) 675{ 676 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]); 677 struct cryptop *crp; 678 const struct auth_hash *esph; 679 const struct enc_xform *espx; 680 struct mbuf *mo = NULL; 681 struct xform_data *xd; 682 struct secasindex *saidx; 683 unsigned char *pad; 684 uint8_t *ivp; 685 uint64_t cntr; 686 crypto_session_t cryptoid; 687 int hlen, rlen, padding, blks, alen, i, roff; 688 int error, maxpacketsize; 689 uint8_t prot; 690 uint32_t seqh; 691 const struct crypto_session_params *csp; 692 693 IPSEC_ASSERT(sav != NULL, ("null SA")); 694 esph = sav->tdb_authalgxform; 695 espx = sav->tdb_encalgxform; 696 IPSEC_ASSERT(espx != NULL, ("null encoding xform")); 697 698 if (sav->flags & SADB_X_EXT_OLD) 699 hlen = sizeof (struct esp) + sav->ivlen; 700 else 701 hlen = sizeof (struct newesp) + sav->ivlen; 702 703 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 704 /* 705 * RFC4303 2.4 Requires 4 byte alignment. 706 * Old versions of FreeBSD can't decrypt partial blocks encrypted 707 * with AES-CTR. Align payload to native_blocksize (16 bytes) 708 * in order to preserve compatibility. 709 */ 710 if (SAV_ISCTR(sav) && V_esp_ctr_compatibility) 711 blks = MAX(4, espx->native_blocksize); /* Cipher blocksize */ 712 else 713 blks = MAX(4, espx->blocksize); 714 715 /* XXX clamp padding length a la KAME??? */ 716 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 717 718 alen = xform_ah_authsize(esph); 719 720 ESPSTAT_INC(esps_output); 721 722 saidx = &sav->sah->saidx; 723 /* Check for maximum packet size violations. */ 724 switch (saidx->dst.sa.sa_family) { 725#ifdef INET 726 case AF_INET: 727 maxpacketsize = IP_MAXPACKET; 728 break; 729#endif /* INET */ 730#ifdef INET6 731 case AF_INET6: 732 maxpacketsize = IPV6_MAXPACKET; 733 break; 734#endif /* INET6 */ 735 default: 736 DPRINTF(("%s: unknown/unsupported protocol " 737 "family %d, SA %s/%08lx\n", __func__, 738 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst, 739 buf, sizeof(buf)), (u_long) ntohl(sav->spi))); 740 ESPSTAT_INC(esps_nopf); 741 error = EPFNOSUPPORT; 742 goto bad; 743 } 744 /* 745 DPRINTF(("%s: skip %d hlen %d rlen %d padding %d alen %d blksd %d\n", 746 __func__, skip, hlen, rlen, padding, alen, blks)); */ 747 if (skip + hlen + rlen + padding + alen > maxpacketsize) { 748 DPRINTF(("%s: packet in SA %s/%08lx got too big " 749 "(len %u, max len %u)\n", __func__, 750 ipsec_address(&saidx->dst, buf, sizeof(buf)), 751 (u_long) ntohl(sav->spi), 752 skip + hlen + rlen + padding + alen, maxpacketsize)); 753 ESPSTAT_INC(esps_toobig); 754 error = EMSGSIZE; 755 goto bad; 756 } 757 758 /* Update the counters. */ 759 ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip); 760 761 m = m_unshare(m, M_NOWAIT); 762 if (m == NULL) { 763 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 764 ipsec_address(&saidx->dst, buf, sizeof(buf)), 765 (u_long) ntohl(sav->spi))); 766 ESPSTAT_INC(esps_hdrops); 767 error = ENOBUFS; 768 goto bad; 769 } 770 771 /* Inject ESP header. */ 772 mo = m_makespace(m, skip, hlen, &roff); 773 if (mo == NULL) { 774 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", 775 __func__, hlen, ipsec_address(&saidx->dst, buf, 776 sizeof(buf)), (u_long) ntohl(sav->spi))); 777 ESPSTAT_INC(esps_hdrops); /* XXX diffs from openbsd */ 778 error = ENOBUFS; 779 goto bad; 780 } 781 782 /* Initialize ESP header. */ 783 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, 784 sizeof(uint32_t)); 785 SECASVAR_LOCK(sav); 786 if (sav->replay) { 787 uint32_t replay; 788 789#ifdef REGRESSION 790 /* Emulate replay attack when ipsec_replay is TRUE. */ 791 if (!V_ipsec_replay) 792#endif 793 sav->replay->count++; 794 replay = htonl((uint32_t)sav->replay->count); 795 796 bcopy((caddr_t) &replay, mtod(mo, caddr_t) + roff + 797 sizeof(uint32_t), sizeof(uint32_t)); 798 799 seqh = htonl((uint32_t)(sav->replay->count >> IPSEC_SEQH_SHIFT)); 800 } 801 cryptoid = sav->tdb_cryptoid; 802 if (SAV_ISCTRORGCM(sav)) 803 cntr = sav->cntr++; 804 SECASVAR_UNLOCK(sav); 805 806 /* 807 * Add padding -- better to do it ourselves than use the crypto engine, 808 * although if/when we support compression, we'd have to do that. 809 */ 810 pad = (u_char *) m_pad(m, padding + alen); 811 if (pad == NULL) { 812 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__, 813 ipsec_address(&saidx->dst, buf, sizeof(buf)), 814 (u_long) ntohl(sav->spi))); 815 m = NULL; /* NB: free'd by m_pad */ 816 error = ENOBUFS; 817 goto bad; 818 } 819 820 /* 821 * Add padding: random, zero, or self-describing. 822 * XXX catch unexpected setting 823 */ 824 switch (sav->flags & SADB_X_EXT_PMASK) { 825 case SADB_X_EXT_PRAND: 826 arc4random_buf(pad, padding - 2); 827 break; 828 case SADB_X_EXT_PZERO: 829 bzero(pad, padding - 2); 830 break; 831 case SADB_X_EXT_PSEQ: 832 for (i = 0; i < padding - 2; i++) 833 pad[i] = i+1; 834 break; 835 } 836 837 /* Fix padding length and Next Protocol in padding itself. */ 838 pad[padding - 2] = padding - 2; 839 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 840 841 /* Fix Next Protocol in IPv4/IPv6 header. */ 842 prot = IPPROTO_ESP; 843 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); 844 845 /* Get crypto descriptor. */ 846 crp = crypto_getreq(cryptoid, M_NOWAIT); 847 if (crp == NULL) { 848 DPRINTF(("%s: failed to acquire crypto descriptor\n", 849 __func__)); 850 ESPSTAT_INC(esps_crypto); 851 error = ENOBUFS; 852 goto bad; 853 } 854 855 /* IPsec-specific opaque crypto info. */ 856 xd = malloc(sizeof(struct xform_data), M_XDATA, M_NOWAIT | M_ZERO); 857 if (xd == NULL) { 858 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 859 goto xd_fail; 860 } 861 862 /* Encryption descriptor. */ 863 crp->crp_payload_start = skip + hlen; 864 crp->crp_payload_length = m->m_pkthdr.len - (skip + hlen + alen); 865 crp->crp_op = CRYPTO_OP_ENCRYPT; 866 867 /* Generate cipher and ESP IVs. */ 868 ivp = &crp->crp_iv[0]; 869 if (SAV_ISCTRORGCM(sav)) { 870 /* 871 * See comment in esp_input() for details on the 872 * cipher IV. A simple per-SA counter stored in 873 * 'cntr' is used as the explicit ESP IV. 874 */ 875 memcpy(ivp, sav->key_enc->key_data + 876 _KEYLEN(sav->key_enc) - 4, 4); 877 be64enc(&ivp[4], cntr); 878 if (SAV_ISCTR(sav)) { 879 be32enc(&ivp[sav->ivlen + 4], 1); 880 } 881 m_copyback(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); 882 crp->crp_flags |= CRYPTO_F_IV_SEPARATE; 883 } else if (sav->ivlen != 0) { 884 arc4rand(ivp, sav->ivlen, 0); 885 crp->crp_iv_start = skip + hlen - sav->ivlen; 886 m_copyback(m, crp->crp_iv_start, sav->ivlen, ivp); 887 } 888 889 /* Callback parameters */ 890 xd->sp = sp; 891 xd->sav = sav; 892 xd->idx = idx; 893 xd->cryptoid = cryptoid; 894 xd->vnet = curvnet; 895 896 /* Crypto operation descriptor. */ 897 crp->crp_flags |= CRYPTO_F_CBIFSYNC; 898 if (V_async_crypto) 899 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 900 crypto_use_mbuf(crp, m); 901 crp->crp_callback = esp_output_cb; 902 crp->crp_opaque = xd; 903 904 if (esph) { 905 /* Authentication descriptor. */ 906 crp->crp_op |= CRYPTO_OP_COMPUTE_DIGEST; 907 if (SAV_ISGCM(sav)) 908 crp->crp_aad_length = 8; /* RFC4106 5, SPI + SN */ 909 else 910 crp->crp_aad_length = hlen; 911 912 csp = crypto_get_params(crp->crp_session); 913 if (csp->csp_flags & CSP_F_SEPARATE_AAD && 914 sav->replay != NULL) { 915 int aad_skip; 916 917 crp->crp_aad_length += sizeof(seqh); 918 crp->crp_aad = malloc(crp->crp_aad_length, M_XDATA, M_NOWAIT); 919 if (crp->crp_aad == NULL) { 920 DPRINTF(("%s: failed to allocate xform_data\n", 921 __func__)); 922 goto crp_aad_fail; 923 } 924 925 /* SPI */ 926 m_copydata(m, skip, SPI_SIZE, crp->crp_aad); 927 aad_skip = SPI_SIZE; 928 929 /* ESN */ 930 bcopy(&seqh, (char *)crp->crp_aad + aad_skip, sizeof(seqh)); 931 aad_skip += sizeof(seqh); 932 933 /* Rest of aad */ 934 if (crp->crp_aad_length - aad_skip > 0) 935 m_copydata(m, skip + SPI_SIZE, 936 crp->crp_aad_length - aad_skip, 937 (char *)crp->crp_aad + aad_skip); 938 } else 939 crp->crp_aad_start = skip; 940 941 if (csp->csp_flags & CSP_F_ESN && sav->replay != NULL) 942 memcpy(crp->crp_esn, &seqh, sizeof(seqh)); 943 944 crp->crp_digest_start = m->m_pkthdr.len - alen; 945 } 946 947 return crypto_dispatch(crp); 948 949crp_aad_fail: 950 free(xd, M_XDATA); 951xd_fail: 952 crypto_freereq(crp); 953 ESPSTAT_INC(esps_crypto); 954 error = ENOBUFS; 955bad: 956 if (m) 957 m_freem(m); 958 key_freesav(&sav); 959 key_freesp(&sp); 960 return (error); 961} 962/* 963 * ESP output callback from the crypto driver. 964 */ 965static int 966esp_output_cb(struct cryptop *crp) 967{ 968 struct xform_data *xd; 969 struct secpolicy *sp; 970 struct secasvar *sav; 971 struct mbuf *m; 972 crypto_session_t cryptoid; 973 u_int idx; 974 int error; 975 976 xd = (struct xform_data *) crp->crp_opaque; 977 CURVNET_SET(xd->vnet); 978 m = crp->crp_buf.cb_mbuf; 979 sp = xd->sp; 980 sav = xd->sav; 981 idx = xd->idx; 982 cryptoid = xd->cryptoid; 983 984 /* Check for crypto errors. */ 985 if (crp->crp_etype) { 986 if (crp->crp_etype == EAGAIN) { 987 /* Reset the session ID */ 988 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 989 crypto_freesession(cryptoid); 990 xd->cryptoid = crp->crp_session; 991 CURVNET_RESTORE(); 992 return (crypto_dispatch(crp)); 993 } 994 ESPSTAT_INC(esps_noxform); 995 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 996 error = crp->crp_etype; 997 m_freem(m); 998 goto bad; 999 } 1000 1001 /* Shouldn't happen... */ 1002 if (m == NULL) { 1003 ESPSTAT_INC(esps_crypto); 1004 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 1005 error = EINVAL; 1006 goto bad; 1007 } 1008 free(xd, M_XDATA); 1009 free(crp->crp_aad, M_XDATA); 1010 crypto_freereq(crp); 1011 ESPSTAT_INC(esps_hist[sav->alg_enc]); 1012 if (sav->tdb_authalgxform != NULL) 1013 AHSTAT_INC(ahs_hist[sav->alg_auth]); 1014 1015#ifdef REGRESSION 1016 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 1017 if (V_ipsec_integrity) { 1018 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN]; 1019 const struct auth_hash *esph; 1020 1021 /* 1022 * Corrupt HMAC if we want to test integrity verification of 1023 * the other side. 1024 */ 1025 esph = sav->tdb_authalgxform; 1026 if (esph != NULL) { 1027 int alen; 1028 1029 alen = xform_ah_authsize(esph); 1030 m_copyback(m, m->m_pkthdr.len - alen, 1031 alen, ipseczeroes); 1032 } 1033 } 1034#endif 1035 1036 /* NB: m is reclaimed by ipsec_process_done. */ 1037 error = ipsec_process_done(m, sp, sav, idx); 1038 CURVNET_RESTORE(); 1039 return (error); 1040bad: 1041 CURVNET_RESTORE(); 1042 free(xd, M_XDATA); 1043 free(crp->crp_aad, M_XDATA); 1044 crypto_freereq(crp); 1045 key_freesav(&sav); 1046 key_freesp(&sp); 1047 return (error); 1048} 1049 1050static struct xformsw esp_xformsw = { 1051 .xf_type = XF_ESP, 1052 .xf_name = "IPsec ESP", 1053 .xf_init = esp_init, 1054 .xf_cleanup = esp_cleanup, 1055 .xf_input = esp_input, 1056 .xf_output = esp_output, 1057}; 1058 1059SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 1060 xform_attach, &esp_xformsw); 1061SYSUNINIT(esp_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 1062 xform_detach, &esp_xformsw); 1063