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sys/netinet/ip_esp.c
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1 /* $OpenBSD: ip_esp.c,v 1.195 2022/05/03 09:18:11 claudio Exp $ */ 2 /* 3 * The authors of this code are John Ioannidis (ji@tla.org), 4 * Angelos D. Keromytis (kermit@csd.uch.gr) and 5 * Niels Provos (provos@physnet.uni-hamburg.de). 6 * 7 * The original version of this code was written by John Ioannidis 8 * for BSD/OS in Athens, Greece, in November 1995. 9 * 10 * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996, 11 * by Angelos D. Keromytis. 12 * 13 * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis 14 * and Niels Provos. 15 * 16 * Additional features in 1999 by Angelos D. Keromytis. 17 * 18 * Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis, 19 * Angelos D. Keromytis and Niels Provos. 20 * Copyright (c) 2001 Angelos D. Keromytis. 21 * 22 * Permission to use, copy, and modify this software with or without fee 23 * is hereby granted, provided that this entire notice is included in 24 * all copies of any software which is or includes a copy or 25 * modification of this software. 26 * You may use this code under the GNU public license if you so wish. Please 27 * contribute changes back to the authors under this freer than GPL license 28 * so that we may further the use of strong encryption without limitations to 29 * all. 30 * 31 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR 32 * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY 33 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE 34 * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR 35 * PURPOSE. 36 */ 37 38 #include "pfsync.h" 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/mbuf.h> 43 #include <sys/socket.h> 44 45 #include <net/if.h> 46 #include <net/if_var.h> 47 #include <net/bpf.h> 48 49 #include <netinet/in.h> 50 #include <netinet/ip.h> 51 #include <netinet/ip_var.h> 52 53 #ifdef INET6 54 #include <netinet/ip6.h> 55 #endif /* INET6 */ 56 57 #include <netinet/ip_ipsp.h> 58 #include <netinet/ip_esp.h> 59 #include <net/pfkeyv2.h> 60 #include <net/if_enc.h> 61 62 #if NPFSYNC > 0 63 #include <net/pfvar.h> 64 #include <net/if_pfsync.h> 65 #endif /* NPFSYNC > 0 */ 66 67 #include <crypto/cryptodev.h> 68 #include <crypto/xform.h> 69 70 #include "bpfilter.h" 71 72 #ifdef ENCDEBUG 73 #define DPRINTF(fmt, args...) \ 74 do { \ 75 if (encdebug) \ 76 printf("%s: " fmt "\n", __func__, ## args); \ 77 } while (0) 78 #else 79 #define DPRINTF(fmt, args...) \ 80 do { } while (0) 81 #endif 82 83 /* 84 * esp_attach() is called from the transformation initialization code. 85 */ 86 int 87 esp_attach(void) 88 { 89 return 0; 90 } 91 92 /* 93 * esp_init() is called when an SPI is being set up. 94 */ 95 int 96 esp_init(struct tdb *tdbp, const struct xformsw *xsp, struct ipsecinit *ii) 97 { 98 const struct enc_xform *txform = NULL; 99 const struct auth_hash *thash = NULL; 100 struct cryptoini cria, crie, crin; 101 int error; 102 103 if (!ii->ii_encalg && !ii->ii_authalg) { 104 DPRINTF("neither authentication nor encryption algorithm " 105 "given"); 106 return EINVAL; 107 } 108 109 if (ii->ii_encalg) { 110 switch (ii->ii_encalg) { 111 case SADB_EALG_NULL: 112 txform = &enc_xform_null; 113 break; 114 115 case SADB_EALG_3DESCBC: 116 txform = &enc_xform_3des; 117 break; 118 119 case SADB_X_EALG_AES: 120 txform = &enc_xform_aes; 121 break; 122 123 case SADB_X_EALG_AESCTR: 124 txform = &enc_xform_aes_ctr; 125 break; 126 127 case SADB_X_EALG_AESGCM16: 128 txform = &enc_xform_aes_gcm; 129 break; 130 131 case SADB_X_EALG_AESGMAC: 132 txform = &enc_xform_aes_gmac; 133 break; 134 135 case SADB_X_EALG_CHACHA20POLY1305: 136 txform = &enc_xform_chacha20_poly1305; 137 break; 138 139 case SADB_X_EALG_BLF: 140 txform = &enc_xform_blf; 141 break; 142 143 case SADB_X_EALG_CAST: 144 txform = &enc_xform_cast5; 145 break; 146 147 default: 148 DPRINTF("unsupported encryption algorithm %d " 149 "specified", 150 ii->ii_encalg); 151 return EINVAL; 152 } 153 154 if (ii->ii_enckeylen < txform->minkey) { 155 DPRINTF("keylength %d too small (min length is %d) " 156 "for algorithm %s", 157 ii->ii_enckeylen, txform->minkey, txform->name); 158 return EINVAL; 159 } 160 161 if (ii->ii_enckeylen > txform->maxkey) { 162 DPRINTF("keylength %d too large (max length is %d) " 163 "for algorithm %s", 164 ii->ii_enckeylen, txform->maxkey, txform->name); 165 return EINVAL; 166 } 167 168 if (ii->ii_encalg == SADB_X_EALG_AESGCM16 || 169 ii->ii_encalg == SADB_X_EALG_AESGMAC) { 170 switch (ii->ii_enckeylen) { 171 case 20: 172 ii->ii_authalg = SADB_X_AALG_AES128GMAC; 173 break; 174 case 28: 175 ii->ii_authalg = SADB_X_AALG_AES192GMAC; 176 break; 177 case 36: 178 ii->ii_authalg = SADB_X_AALG_AES256GMAC; 179 break; 180 } 181 ii->ii_authkeylen = ii->ii_enckeylen; 182 ii->ii_authkey = ii->ii_enckey; 183 } else if (ii->ii_encalg == SADB_X_EALG_CHACHA20POLY1305) { 184 ii->ii_authalg = SADB_X_AALG_CHACHA20POLY1305; 185 ii->ii_authkeylen = ii->ii_enckeylen; 186 ii->ii_authkey = ii->ii_enckey; 187 } 188 189 tdbp->tdb_encalgxform = txform; 190 191 DPRINTF("initialized TDB with enc algorithm %s", txform->name); 192 193 tdbp->tdb_ivlen = txform->ivsize; 194 } 195 196 if (ii->ii_authalg) { 197 switch (ii->ii_authalg) { 198 case SADB_AALG_MD5HMAC: 199 thash = &auth_hash_hmac_md5_96; 200 break; 201 202 case SADB_AALG_SHA1HMAC: 203 thash = &auth_hash_hmac_sha1_96; 204 break; 205 206 case SADB_X_AALG_RIPEMD160HMAC: 207 thash = &auth_hash_hmac_ripemd_160_96; 208 break; 209 210 case SADB_X_AALG_SHA2_256: 211 thash = &auth_hash_hmac_sha2_256_128; 212 break; 213 214 case SADB_X_AALG_SHA2_384: 215 thash = &auth_hash_hmac_sha2_384_192; 216 break; 217 218 case SADB_X_AALG_SHA2_512: 219 thash = &auth_hash_hmac_sha2_512_256; 220 break; 221 222 case SADB_X_AALG_AES128GMAC: 223 thash = &auth_hash_gmac_aes_128; 224 break; 225 226 case SADB_X_AALG_AES192GMAC: 227 thash = &auth_hash_gmac_aes_192; 228 break; 229 230 case SADB_X_AALG_AES256GMAC: 231 thash = &auth_hash_gmac_aes_256; 232 break; 233 234 case SADB_X_AALG_CHACHA20POLY1305: 235 thash = &auth_hash_chacha20_poly1305; 236 break; 237 238 default: 239 DPRINTF("unsupported authentication algorithm %d " 240 "specified", 241 ii->ii_authalg); 242 return EINVAL; 243 } 244 245 if (ii->ii_authkeylen != thash->keysize) { 246 DPRINTF("keylength %d doesn't match algorithm %s " 247 "keysize (%d)", 248 ii->ii_authkeylen, thash->name, thash->keysize); 249 return EINVAL; 250 } 251 252 tdbp->tdb_authalgxform = thash; 253 254 DPRINTF("initialized TDB with hash algorithm %s", thash->name); 255 } 256 257 tdbp->tdb_xform = xsp; 258 tdbp->tdb_rpl = AH_HMAC_INITIAL_RPL; 259 260 /* Initialize crypto session */ 261 if (tdbp->tdb_encalgxform) { 262 /* Save the raw keys */ 263 tdbp->tdb_emxkeylen = ii->ii_enckeylen; 264 tdbp->tdb_emxkey = malloc(tdbp->tdb_emxkeylen, M_XDATA, 265 M_WAITOK); 266 memcpy(tdbp->tdb_emxkey, ii->ii_enckey, tdbp->tdb_emxkeylen); 267 268 memset(&crie, 0, sizeof(crie)); 269 270 crie.cri_alg = tdbp->tdb_encalgxform->type; 271 272 if (tdbp->tdb_authalgxform) 273 crie.cri_next = &cria; 274 else 275 crie.cri_next = NULL; 276 277 crie.cri_klen = ii->ii_enckeylen * 8; 278 crie.cri_key = ii->ii_enckey; 279 /* XXX Rounds ? */ 280 } 281 282 if (tdbp->tdb_authalgxform) { 283 /* Save the raw keys */ 284 tdbp->tdb_amxkeylen = ii->ii_authkeylen; 285 tdbp->tdb_amxkey = malloc(tdbp->tdb_amxkeylen, M_XDATA, 286 M_WAITOK); 287 memcpy(tdbp->tdb_amxkey, ii->ii_authkey, tdbp->tdb_amxkeylen); 288 289 memset(&cria, 0, sizeof(cria)); 290 291 cria.cri_alg = tdbp->tdb_authalgxform->type; 292 293 if ((tdbp->tdb_wnd > 0) && (tdbp->tdb_flags & TDBF_ESN)) { 294 memset(&crin, 0, sizeof(crin)); 295 crin.cri_alg = CRYPTO_ESN; 296 cria.cri_next = &crin; 297 } 298 299 cria.cri_klen = ii->ii_authkeylen * 8; 300 cria.cri_key = ii->ii_authkey; 301 } 302 303 KERNEL_LOCK(); 304 error = crypto_newsession(&tdbp->tdb_cryptoid, 305 (tdbp->tdb_encalgxform ? &crie : &cria), 0); 306 KERNEL_UNLOCK(); 307 return error; 308 } 309 310 /* 311 * Paranoia. 312 */ 313 int 314 esp_zeroize(struct tdb *tdbp) 315 { 316 int error; 317 318 if (tdbp->tdb_amxkey) { 319 explicit_bzero(tdbp->tdb_amxkey, tdbp->tdb_amxkeylen); 320 free(tdbp->tdb_amxkey, M_XDATA, tdbp->tdb_amxkeylen); 321 tdbp->tdb_amxkey = NULL; 322 } 323 324 if (tdbp->tdb_emxkey) { 325 explicit_bzero(tdbp->tdb_emxkey, tdbp->tdb_emxkeylen); 326 free(tdbp->tdb_emxkey, M_XDATA, tdbp->tdb_emxkeylen); 327 tdbp->tdb_emxkey = NULL; 328 } 329 330 KERNEL_LOCK(); 331 error = crypto_freesession(tdbp->tdb_cryptoid); 332 KERNEL_UNLOCK(); 333 tdbp->tdb_cryptoid = 0; 334 return error; 335 } 336 337 #define MAXBUFSIZ (AH_ALEN_MAX > ESP_MAX_IVS ? AH_ALEN_MAX : ESP_MAX_IVS) 338 339 /* 340 * ESP input processing, called (eventually) through the protocol switch. 341 */ 342 int 343 esp_input(struct mbuf **mp, struct tdb *tdb, int skip, int protoff) 344 { 345 const struct auth_hash *esph = tdb->tdb_authalgxform; 346 const struct enc_xform *espx = tdb->tdb_encalgxform; 347 struct mbuf *m = *mp, *m1, *mo; 348 struct cryptodesc *crde = NULL, *crda = NULL; 349 struct cryptop *crp = NULL; 350 int plen, alen, hlen, error, roff; 351 uint32_t btsx, esn; 352 #ifdef ENCDEBUG 353 char buf[INET6_ADDRSTRLEN]; 354 #endif 355 uint8_t abuf[AH_HMAC_MAX_HASHLEN]; 356 uint8_t lastthree[3], aalg[AH_HMAC_MAX_HASHLEN]; 357 358 /* Determine the ESP header length */ 359 hlen = 2 * sizeof(u_int32_t) + tdb->tdb_ivlen; /* "new" ESP */ 360 alen = esph ? esph->authsize : 0; 361 plen = m->m_pkthdr.len - (skip + hlen + alen); 362 if (plen <= 0) { 363 DPRINTF("invalid payload length"); 364 espstat_inc(esps_badilen); 365 goto drop; 366 } 367 368 if (espx) { 369 /* 370 * Verify payload length is multiple of encryption algorithm 371 * block size. 372 */ 373 if (plen & (espx->blocksize - 1)) { 374 DPRINTF("payload of %d octets not a multiple " 375 "of %d octets, SA %s/%08x", 376 plen, espx->blocksize, 377 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 378 ntohl(tdb->tdb_spi)); 379 espstat_inc(esps_badilen); 380 goto drop; 381 } 382 } 383 384 /* Replay window checking, if appropriate -- no value commitment. */ 385 if (tdb->tdb_wnd > 0) { 386 m_copydata(m, skip + sizeof(u_int32_t), sizeof(u_int32_t), 387 &btsx); 388 btsx = ntohl(btsx); 389 390 switch (checkreplaywindow(tdb, tdb->tdb_rpl, btsx, &esn, 0)) { 391 case 0: /* All's well */ 392 break; 393 case 1: 394 DPRINTF("replay counter wrapped for SA %s/%08x", 395 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 396 ntohl(tdb->tdb_spi)); 397 espstat_inc(esps_wrap); 398 goto drop; 399 case 2: 400 DPRINTF("old packet received in SA %s/%08x", 401 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 402 ntohl(tdb->tdb_spi)); 403 espstat_inc(esps_replay); 404 goto drop; 405 case 3: 406 DPRINTF("duplicate packet received in SA %s/%08x", 407 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 408 ntohl(tdb->tdb_spi)); 409 espstat_inc(esps_replay); 410 goto drop; 411 default: 412 DPRINTF("bogus value from checkreplaywindow() " 413 "in SA %s/%08x", 414 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 415 ntohl(tdb->tdb_spi)); 416 espstat_inc(esps_replay); 417 goto drop; 418 } 419 } 420 421 /* Update the counters */ 422 tdb->tdb_cur_bytes += plen; 423 tdbstat_add(tdb, tdb_ibytes, plen); 424 espstat_add(esps_ibytes, plen); 425 426 /* Hard expiration */ 427 if ((tdb->tdb_flags & TDBF_BYTES) && 428 (tdb->tdb_cur_bytes >= tdb->tdb_exp_bytes)) { 429 ipsecstat_inc(ipsec_exctdb); 430 pfkeyv2_expire(tdb, SADB_EXT_LIFETIME_HARD); 431 tdb_delete(tdb); 432 goto drop; 433 } 434 435 /* Notify on soft expiration */ 436 mtx_enter(&tdb->tdb_mtx); 437 if ((tdb->tdb_flags & TDBF_SOFT_BYTES) && 438 (tdb->tdb_cur_bytes >= tdb->tdb_soft_bytes)) { 439 tdb->tdb_flags &= ~TDBF_SOFT_BYTES; /* Turn off checking */ 440 mtx_leave(&tdb->tdb_mtx); 441 /* may sleep in solock() for the pfkey socket */ 442 pfkeyv2_expire(tdb, SADB_EXT_LIFETIME_SOFT); 443 } else 444 mtx_leave(&tdb->tdb_mtx); 445 446 /* Get crypto descriptors */ 447 crp = crypto_getreq(esph && espx ? 2 : 1); 448 if (crp == NULL) { 449 DPRINTF("failed to acquire crypto descriptors"); 450 espstat_inc(esps_crypto); 451 goto drop; 452 } 453 454 if (esph) { 455 crda = &crp->crp_desc[0]; 456 crde = &crp->crp_desc[1]; 457 458 /* Authentication descriptor */ 459 crda->crd_skip = skip; 460 crda->crd_inject = m->m_pkthdr.len - alen; 461 462 crda->crd_alg = esph->type; 463 crda->crd_key = tdb->tdb_amxkey; 464 crda->crd_klen = tdb->tdb_amxkeylen * 8; 465 466 if ((tdb->tdb_wnd > 0) && (tdb->tdb_flags & TDBF_ESN)) { 467 esn = htonl(esn); 468 memcpy(crda->crd_esn, &esn, 4); 469 crda->crd_flags |= CRD_F_ESN; 470 } 471 472 if (espx && 473 (espx->type == CRYPTO_AES_GCM_16 || 474 espx->type == CRYPTO_CHACHA20_POLY1305)) 475 crda->crd_len = hlen - tdb->tdb_ivlen; 476 else 477 crda->crd_len = m->m_pkthdr.len - (skip + alen); 478 479 /* Copy the authenticator */ 480 m_copydata(m, m->m_pkthdr.len - alen, alen, abuf); 481 } else 482 crde = &crp->crp_desc[0]; 483 484 /* Crypto operation descriptor */ 485 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 486 crp->crp_flags = CRYPTO_F_IMBUF; 487 crp->crp_buf = (caddr_t)m; 488 crp->crp_sid = tdb->tdb_cryptoid; 489 490 /* Decryption descriptor */ 491 if (espx) { 492 crde->crd_skip = skip + hlen; 493 crde->crd_inject = skip + hlen - tdb->tdb_ivlen; 494 crde->crd_alg = espx->type; 495 crde->crd_key = tdb->tdb_emxkey; 496 crde->crd_klen = tdb->tdb_emxkeylen * 8; 497 /* XXX Rounds ? */ 498 499 if (crde->crd_alg == CRYPTO_AES_GMAC) 500 crde->crd_len = 0; 501 else 502 crde->crd_len = plen; 503 } 504 505 while ((error = crypto_invoke(crp)) == EAGAIN) { 506 /* Reset the session ID */ 507 if (tdb->tdb_cryptoid != 0) 508 tdb->tdb_cryptoid = crp->crp_sid; 509 } 510 if (error) { 511 DPRINTF("crypto error %d", error); 512 ipsecstat_inc(ipsec_noxform); 513 goto drop; 514 } 515 516 /* Release the crypto descriptors */ 517 crypto_freereq(crp); 518 crp = NULL; 519 520 /* If authentication was performed, check now. */ 521 if (esph != NULL) { 522 /* Copy the authenticator from the packet */ 523 m_copydata(m, m->m_pkthdr.len - esph->authsize, 524 esph->authsize, aalg); 525 526 /* Verify authenticator */ 527 if (timingsafe_bcmp(abuf, aalg, esph->authsize)) { 528 DPRINTF("authentication failed for packet " 529 "in SA %s/%08x", 530 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 531 ntohl(tdb->tdb_spi)); 532 espstat_inc(esps_badauth); 533 goto drop; 534 } 535 536 /* Remove trailing authenticator */ 537 m_adj(m, -(esph->authsize)); 538 } 539 540 /* Replay window checking, if appropriate */ 541 if (tdb->tdb_wnd > 0) { 542 m_copydata(m, skip + sizeof(u_int32_t), sizeof(u_int32_t), 543 &btsx); 544 btsx = ntohl(btsx); 545 546 switch (checkreplaywindow(tdb, tdb->tdb_rpl, btsx, &esn, 1)) { 547 case 0: /* All's well */ 548 #if NPFSYNC > 0 549 pfsync_update_tdb(tdb,0); 550 #endif 551 break; 552 553 case 1: 554 DPRINTF("replay counter wrapped for SA %s/%08x", 555 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 556 ntohl(tdb->tdb_spi)); 557 espstat_inc(esps_wrap); 558 goto drop; 559 case 2: 560 DPRINTF("old packet received in SA %s/%08x", 561 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 562 ntohl(tdb->tdb_spi)); 563 espstat_inc(esps_replay); 564 goto drop; 565 case 3: 566 DPRINTF("duplicate packet received in SA %s/%08x", 567 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 568 ntohl(tdb->tdb_spi)); 569 espstat_inc(esps_replay); 570 goto drop; 571 default: 572 DPRINTF("bogus value from checkreplaywindow() " 573 "in SA %s/%08x", 574 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 575 ntohl(tdb->tdb_spi)); 576 espstat_inc(esps_replay); 577 goto drop; 578 } 579 } 580 581 /* Find beginning of ESP header */ 582 m1 = m_getptr(m, skip, &roff); 583 if (m1 == NULL) { 584 DPRINTF("bad mbuf chain, SA %s/%08x", 585 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 586 ntohl(tdb->tdb_spi)); 587 espstat_inc(esps_hdrops); 588 goto drop; 589 } 590 591 /* Remove the ESP header and IV from the mbuf. */ 592 if (roff == 0) { 593 /* The ESP header was conveniently at the beginning of the mbuf */ 594 m_adj(m1, hlen); 595 /* 596 * If m1 is the first mbuf, it has set M_PKTHDR and m_adj() 597 * has already adjusted the packet header length for us. 598 */ 599 if (m1 != m) 600 m->m_pkthdr.len -= hlen; 601 } else if (roff + hlen >= m1->m_len) { 602 int adjlen; 603 604 /* 605 * Part or all of the ESP header is at the end of this mbuf, so 606 * first let's remove the remainder of the ESP header from the 607 * beginning of the remainder of the mbuf chain, if any. 608 */ 609 if (roff + hlen > m1->m_len) { 610 adjlen = roff + hlen - m1->m_len; 611 612 /* Adjust the next mbuf by the remainder */ 613 m_adj(m1->m_next, adjlen); 614 615 /* The second mbuf is guaranteed not to have a pkthdr */ 616 m->m_pkthdr.len -= adjlen; 617 } 618 619 /* Now, let's unlink the mbuf chain for a second...*/ 620 mo = m1->m_next; 621 m1->m_next = NULL; 622 623 /* ...and trim the end of the first part of the chain...sick */ 624 adjlen = m1->m_len - roff; 625 m_adj(m1, -adjlen); 626 /* 627 * If m1 is the first mbuf, it has set M_PKTHDR and m_adj() 628 * has already adjusted the packet header length for us. 629 */ 630 if (m1 != m) 631 m->m_pkthdr.len -= adjlen; 632 633 /* Finally, let's relink */ 634 m1->m_next = mo; 635 } else { 636 /* 637 * The ESP header lies in the "middle" of the mbuf...do an 638 * overlapping copy of the remainder of the mbuf over the ESP 639 * header. 640 */ 641 memmove(mtod(m1, u_char *) + roff, 642 mtod(m1, u_char *) + roff + hlen, 643 m1->m_len - (roff + hlen)); 644 m1->m_len -= hlen; 645 m->m_pkthdr.len -= hlen; 646 } 647 648 /* Save the last three bytes of decrypted data */ 649 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 650 651 /* Verify pad length */ 652 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 653 DPRINTF("invalid padding length %d for packet in SA %s/%08x", 654 lastthree[1], 655 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 656 ntohl(tdb->tdb_spi)); 657 espstat_inc(esps_badilen); 658 goto drop; 659 } 660 661 /* Verify correct decryption by checking the last padding bytes */ 662 if ((lastthree[1] != lastthree[0]) && (lastthree[1] != 0)) { 663 DPRINTF("decryption failed for packet in SA %s/%08x", 664 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 665 ntohl(tdb->tdb_spi)); 666 espstat_inc(esps_badenc); 667 goto drop; 668 } 669 670 /* Trim the mbuf chain to remove the padding */ 671 m_adj(m, -(lastthree[1] + 2)); 672 673 /* Restore the Next Protocol field */ 674 m_copyback(m, protoff, sizeof(u_int8_t), lastthree + 2, M_NOWAIT); 675 676 /* Back to generic IPsec input processing */ 677 return ipsec_common_input_cb(mp, tdb, skip, protoff); 678 679 drop: 680 m_freemp(mp); 681 crypto_freereq(crp); 682 return IPPROTO_DONE; 683 } 684 685 /* 686 * ESP output routine, called by ipsp_process_packet(). 687 */ 688 int 689 esp_output(struct mbuf *m, struct tdb *tdb, int skip, int protoff) 690 { 691 const struct enc_xform *espx = tdb->tdb_encalgxform; 692 const struct auth_hash *esph = tdb->tdb_authalgxform; 693 int ilen, hlen, rlen, padding, blks, alen, roff, error; 694 uint64_t replay64; 695 uint32_t replay; 696 struct mbuf *mi, *mo = (struct mbuf *) NULL; 697 unsigned char *pad; 698 uint8_t prot; 699 #ifdef ENCDEBUG 700 char buf[INET6_ADDRSTRLEN]; 701 #endif 702 struct cryptodesc *crde = NULL, *crda = NULL; 703 struct cryptop *crp = NULL; 704 #if NBPFILTER > 0 705 struct ifnet *encif; 706 707 if ((encif = enc_getif(tdb->tdb_rdomain, tdb->tdb_tap)) != NULL) { 708 encif->if_opackets++; 709 encif->if_obytes += m->m_pkthdr.len; 710 711 if (encif->if_bpf) { 712 struct enchdr hdr; 713 714 memset(&hdr, 0, sizeof(hdr)); 715 716 hdr.af = tdb->tdb_dst.sa.sa_family; 717 hdr.spi = tdb->tdb_spi; 718 if (espx) 719 hdr.flags |= M_CONF; 720 if (esph) 721 hdr.flags |= M_AUTH; 722 723 bpf_mtap_hdr(encif->if_bpf, (char *)&hdr, 724 ENC_HDRLEN, m, BPF_DIRECTION_OUT); 725 } 726 } 727 #endif 728 729 hlen = 2 * sizeof(u_int32_t) + tdb->tdb_ivlen; 730 731 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 732 if (espx) 733 blks = MAX(espx->blocksize, 4); 734 else 735 blks = 4; /* If no encryption, we have to be 4-byte aligned. */ 736 737 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 738 739 alen = esph ? esph->authsize : 0; 740 espstat_inc(esps_output); 741 742 switch (tdb->tdb_dst.sa.sa_family) { 743 case AF_INET: 744 /* Check for IP maximum packet size violations. */ 745 if (skip + hlen + rlen + padding + alen > IP_MAXPACKET) { 746 DPRINTF("packet in SA %s/%08x got too big", 747 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 748 ntohl(tdb->tdb_spi)); 749 espstat_inc(esps_toobig); 750 error = EMSGSIZE; 751 goto drop; 752 } 753 break; 754 755 #ifdef INET6 756 case AF_INET6: 757 /* Check for IPv6 maximum packet size violations. */ 758 if (skip + hlen + rlen + padding + alen > IPV6_MAXPACKET) { 759 DPRINTF("acket in SA %s/%08x got too big", 760 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 761 ntohl(tdb->tdb_spi)); 762 espstat_inc(esps_toobig); 763 error = EMSGSIZE; 764 goto drop; 765 } 766 break; 767 #endif /* INET6 */ 768 769 default: 770 DPRINTF("unknown/unsupported protocol family %d, SA %s/%08x", 771 tdb->tdb_dst.sa.sa_family, 772 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 773 ntohl(tdb->tdb_spi)); 774 espstat_inc(esps_nopf); 775 error = EPFNOSUPPORT; 776 goto drop; 777 } 778 779 /* Update the counters. */ 780 tdb->tdb_cur_bytes += m->m_pkthdr.len - skip; 781 espstat_add(esps_obytes, m->m_pkthdr.len - skip); 782 783 /* Hard byte expiration. */ 784 if ((tdb->tdb_flags & TDBF_BYTES) && 785 (tdb->tdb_cur_bytes >= tdb->tdb_exp_bytes)) { 786 ipsecstat_inc(ipsec_exctdb); 787 pfkeyv2_expire(tdb, SADB_EXT_LIFETIME_HARD); 788 tdb_delete(tdb); 789 error = EINVAL; 790 goto drop; 791 } 792 793 /* Soft byte expiration. */ 794 mtx_enter(&tdb->tdb_mtx); 795 if ((tdb->tdb_flags & TDBF_SOFT_BYTES) && 796 (tdb->tdb_cur_bytes >= tdb->tdb_soft_bytes)) { 797 tdb->tdb_flags &= ~TDBF_SOFT_BYTES; /* Turn off checking */ 798 mtx_leave(&tdb->tdb_mtx); 799 /* may sleep in solock() for the pfkey socket */ 800 pfkeyv2_expire(tdb, SADB_EXT_LIFETIME_SOFT); 801 } else 802 mtx_leave(&tdb->tdb_mtx); 803 804 /* 805 * Loop through mbuf chain; if we find a readonly mbuf, 806 * copy the packet. 807 */ 808 mi = m; 809 while (mi != NULL && !M_READONLY(mi)) 810 mi = mi->m_next; 811 812 if (mi != NULL) { 813 struct mbuf *n = m_dup_pkt(m, 0, M_DONTWAIT); 814 815 if (n == NULL) { 816 DPRINTF("bad mbuf chain, SA %s/%08x", 817 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 818 ntohl(tdb->tdb_spi)); 819 espstat_inc(esps_hdrops); 820 error = ENOBUFS; 821 goto drop; 822 } 823 824 m_freem(m); 825 m = n; 826 } 827 828 /* Inject ESP header. */ 829 mo = m_makespace(m, skip, hlen, &roff); 830 if (mo == NULL) { 831 DPRINTF("failed to inject ESP header for SA %s/%08x", 832 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 833 ntohl(tdb->tdb_spi)); 834 espstat_inc(esps_hdrops); 835 error = ENOBUFS; 836 goto drop; 837 } 838 839 /* Initialize ESP header. */ 840 memcpy(mtod(mo, caddr_t) + roff, (caddr_t) &tdb->tdb_spi, 841 sizeof(u_int32_t)); 842 replay64 = tdb->tdb_rpl++; /* used for both header and ESN */ 843 replay = htonl((u_int32_t)replay64); 844 memcpy(mtod(mo, caddr_t) + roff + sizeof(u_int32_t), (caddr_t) &replay, 845 sizeof(u_int32_t)); 846 847 #if NPFSYNC > 0 848 pfsync_update_tdb(tdb,1); 849 #endif 850 851 /* 852 * Add padding -- better to do it ourselves than use the crypto engine, 853 * although if/when we support compression, we'd have to do that. 854 */ 855 mo = m_makespace(m, m->m_pkthdr.len, padding + alen, &roff); 856 if (mo == NULL) { 857 DPRINTF("m_makespace() failed for SA %s/%08x", 858 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 859 ntohl(tdb->tdb_spi)); 860 espstat_inc(esps_hdrops); 861 error = ENOBUFS; 862 goto drop; 863 } 864 pad = mtod(mo, caddr_t) + roff; 865 866 /* Apply self-describing padding */ 867 for (ilen = 0; ilen < padding - 2; ilen++) 868 pad[ilen] = ilen + 1; 869 870 /* Fix padding length and Next Protocol in padding itself. */ 871 pad[padding - 2] = padding - 2; 872 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 873 874 /* Fix Next Protocol in IPv4/IPv6 header. */ 875 prot = IPPROTO_ESP; 876 m_copyback(m, protoff, sizeof(u_int8_t), &prot, M_NOWAIT); 877 878 /* Get crypto descriptors. */ 879 crp = crypto_getreq(esph && espx ? 2 : 1); 880 if (crp == NULL) { 881 DPRINTF("failed to acquire crypto descriptors"); 882 espstat_inc(esps_crypto); 883 error = ENOBUFS; 884 goto drop; 885 } 886 887 if (espx) { 888 crde = &crp->crp_desc[0]; 889 crda = &crp->crp_desc[1]; 890 891 /* Encryption descriptor. */ 892 crde->crd_skip = skip + hlen; 893 crde->crd_flags = CRD_F_ENCRYPT | CRD_F_IV_EXPLICIT; 894 crde->crd_inject = skip + hlen - tdb->tdb_ivlen; 895 896 /* Encryption operation. */ 897 crde->crd_alg = espx->type; 898 crde->crd_key = tdb->tdb_emxkey; 899 crde->crd_klen = tdb->tdb_emxkeylen * 8; 900 /* XXX Rounds ? */ 901 902 if (crde->crd_alg == CRYPTO_AES_GMAC) 903 crde->crd_len = 0; 904 else 905 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 906 907 /* GCM & friends just require a NONCE (non-repeating!) */ 908 if (espx->type == CRYPTO_AES_CTR || 909 espx->type == CRYPTO_AES_GCM_16 || 910 espx->type == CRYPTO_CHACHA20_POLY1305) 911 bcopy(&replay64, crde->crd_iv, sizeof(replay64)); 912 else 913 arc4random_buf(crde->crd_iv, espx->ivsize); 914 } else 915 crda = &crp->crp_desc[0]; 916 917 /* Crypto operation descriptor. */ 918 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 919 crp->crp_flags = CRYPTO_F_IMBUF; 920 crp->crp_buf = (caddr_t)m; 921 crp->crp_sid = tdb->tdb_cryptoid; 922 923 if (esph) { 924 /* Authentication descriptor. */ 925 crda->crd_skip = skip; 926 crda->crd_inject = m->m_pkthdr.len - alen; 927 928 /* Authentication operation. */ 929 crda->crd_alg = esph->type; 930 crda->crd_key = tdb->tdb_amxkey; 931 crda->crd_klen = tdb->tdb_amxkeylen * 8; 932 933 if ((tdb->tdb_wnd > 0) && (tdb->tdb_flags & TDBF_ESN)) { 934 u_int32_t esn; 935 936 esn = htonl((u_int32_t)(replay64 >> 32)); 937 memcpy(crda->crd_esn, &esn, 4); 938 crda->crd_flags |= CRD_F_ESN; 939 } 940 941 if (espx && 942 (espx->type == CRYPTO_AES_GCM_16 || 943 espx->type == CRYPTO_CHACHA20_POLY1305)) 944 crda->crd_len = hlen - tdb->tdb_ivlen; 945 else 946 crda->crd_len = m->m_pkthdr.len - (skip + alen); 947 } 948 949 while ((error = crypto_invoke(crp)) == EAGAIN) { 950 /* Reset the session ID */ 951 if (tdb->tdb_cryptoid != 0) 952 tdb->tdb_cryptoid = crp->crp_sid; 953 } 954 if (error) { 955 DPRINTF("crypto error %d", error); 956 ipsecstat_inc(ipsec_noxform); 957 goto drop; 958 } 959 960 /* Release the crypto descriptors */ 961 crypto_freereq(crp); 962 963 /* Call the IPsec input callback. */ 964 error = ipsp_process_done(m, tdb); 965 if (error) 966 espstat_inc(esps_outfail); 967 return (error); 968 969 drop: 970 m_freem(m); 971 crypto_freereq(crp); 972 return error; 973 } 974 975 #define SEEN_SIZE howmany(TDB_REPLAYMAX, 32) 976 977 /* 978 * return 0 on success 979 * return 1 for counter == 0 980 * return 2 for very old packet 981 * return 3 for packet within current window but already received 982 */ 983 int 984 checkreplaywindow(struct tdb *tdb, u_int64_t t, u_int32_t seq, u_int32_t *seqh, 985 int commit) 986 { 987 u_int32_t tl, th, wl; 988 u_int32_t packet, window = TDB_REPLAYMAX - TDB_REPLAYWASTE; 989 int idx, esn = tdb->tdb_flags & TDBF_ESN; 990 991 tl = (u_int32_t)t; 992 th = (u_int32_t)(t >> 32); 993 994 /* Zero SN is not allowed */ 995 if ((esn && seq == 0 && tl <= AH_HMAC_INITIAL_RPL && th == 0) || 996 (!esn && seq == 0)) 997 return (1); 998 999 if (th == 0 && tl < window) 1000 window = tl; 1001 /* Current replay window starts here */ 1002 wl = tl - window + 1; 1003 1004 idx = (seq % TDB_REPLAYMAX) / 32; 1005 packet = 1U << (31 - (seq & 31)); 1006 1007 /* 1008 * We keep the high part intact when: 1009 * 1) the SN is within [wl, 0xffffffff] and the whole window is 1010 * within one subspace; 1011 * 2) the SN is within [0, wl) and window spans two subspaces. 1012 */ 1013 if ((tl >= window - 1 && seq >= wl) || 1014 (tl < window - 1 && seq < wl)) { 1015 *seqh = th; 1016 if (seq > tl) { 1017 if (commit) { 1018 if (seq - tl > window) 1019 memset(tdb->tdb_seen, 0, 1020 sizeof(tdb->tdb_seen)); 1021 else { 1022 int i = (tl % TDB_REPLAYMAX) / 32; 1023 1024 while (i != idx) { 1025 i = (i + 1) % SEEN_SIZE; 1026 tdb->tdb_seen[i] = 0; 1027 } 1028 } 1029 tdb->tdb_seen[idx] |= packet; 1030 tdb->tdb_rpl = ((u_int64_t)*seqh << 32) | seq; 1031 } 1032 } else { 1033 if (tl - seq >= window) 1034 return (2); 1035 if (tdb->tdb_seen[idx] & packet) 1036 return (3); 1037 if (commit) 1038 tdb->tdb_seen[idx] |= packet; 1039 } 1040 return (0); 1041 } 1042 1043 /* Can't wrap if not doing ESN */ 1044 if (!esn) 1045 return (2); 1046 1047 /* 1048 * (3) SN is within [wl, 0xffffffff] and wl is within 1049 * (0xffffffff-window+1, 0xffffffff]. 1050 * This means we got a SN which is within our replay window, 1051 * but in the previous subspace. 1052 */ 1053 if (tl < window - 1 && seq >= wl) { 1054 if (tdb->tdb_seen[idx] & packet) 1055 return (3); 1056 *seqh = th - 1; 1057 if (commit) 1058 tdb->tdb_seen[idx] |= packet; 1059 return (0); 1060 } 1061 1062 /* 1063 * (4) SN has wrapped and the last authenticated SN is in the old 1064 * subspace. 1065 */ 1066 *seqh = th + 1; 1067 if (*seqh == 0) /* Don't let high bit to wrap */ 1068 return (1); 1069 if (commit) { 1070 if (seq - tl > window) 1071 memset(tdb->tdb_seen, 0, sizeof(tdb->tdb_seen)); 1072 else { 1073 int i = (tl % TDB_REPLAYMAX) / 32; 1074 1075 while (i != idx) { 1076 i = (i + 1) % SEEN_SIZE; 1077 tdb->tdb_seen[i] = 0; 1078 } 1079 } 1080 tdb->tdb_seen[idx] |= packet; 1081 tdb->tdb_rpl = ((u_int64_t)*seqh << 32) | seq; 1082 } 1083 1084 return (0); 1085 }
Cache object: 62eb1485467e49eb67a45216333980a5
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