1 /* $OpenBSD: ip_esp.c,v 1.185 2021/11/04 14:45:07 tobhe 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, clen, 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 error = EINVAL; 366 goto drop; 367 } 368 369 if (espx) { 370 /* 371 * Verify payload length is multiple of encryption algorithm 372 * block size. 373 */ 374 if (plen & (espx->blocksize - 1)) { 375 DPRINTF("payload of %d octets not a multiple " 376 "of %d octets, SA %s/%08x", 377 plen, espx->blocksize, 378 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 379 ntohl(tdb->tdb_spi)); 380 espstat_inc(esps_badilen); 381 error = EINVAL; 382 goto drop; 383 } 384 } 385 386 /* Replay window checking, if appropriate -- no value commitment. */ 387 if (tdb->tdb_wnd > 0) { 388 m_copydata(m, skip + sizeof(u_int32_t), sizeof(u_int32_t), 389 &btsx); 390 btsx = ntohl(btsx); 391 392 switch (checkreplaywindow(tdb, tdb->tdb_rpl, btsx, &esn, 0)) { 393 case 0: /* All's well */ 394 break; 395 case 1: 396 DPRINTF("replay counter wrapped for SA %s/%08x", 397 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 398 ntohl(tdb->tdb_spi)); 399 espstat_inc(esps_wrap); 400 error = EACCES; 401 goto drop; 402 case 2: 403 DPRINTF("old packet received in SA %s/%08x", 404 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 405 ntohl(tdb->tdb_spi)); 406 espstat_inc(esps_replay); 407 error = EACCES; 408 goto drop; 409 case 3: 410 DPRINTF("duplicate packet received in SA %s/%08x", 411 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 412 ntohl(tdb->tdb_spi)); 413 espstat_inc(esps_replay); 414 error = EACCES; 415 goto drop; 416 default: 417 DPRINTF("bogus value from checkreplaywindow() " 418 "in SA %s/%08x", 419 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 420 ntohl(tdb->tdb_spi)); 421 espstat_inc(esps_replay); 422 error = EACCES; 423 goto drop; 424 } 425 } 426 427 /* Update the counters */ 428 tdb->tdb_cur_bytes += plen; 429 tdb->tdb_ibytes += plen; 430 espstat_add(esps_ibytes, plen); 431 432 /* Hard expiration */ 433 if ((tdb->tdb_flags & TDBF_BYTES) && 434 (tdb->tdb_cur_bytes >= tdb->tdb_exp_bytes)) { 435 pfkeyv2_expire(tdb, SADB_EXT_LIFETIME_HARD); 436 tdb_delete(tdb); 437 error = ENXIO; 438 goto drop; 439 } 440 441 /* Notify on soft expiration */ 442 if ((tdb->tdb_flags & TDBF_SOFT_BYTES) && 443 (tdb->tdb_cur_bytes >= tdb->tdb_soft_bytes)) { 444 pfkeyv2_expire(tdb, SADB_EXT_LIFETIME_SOFT); 445 tdb->tdb_flags &= ~TDBF_SOFT_BYTES; /* Turn off checking */ 446 } 447 448 /* Get crypto descriptors */ 449 crp = crypto_getreq(esph && espx ? 2 : 1); 450 if (crp == NULL) { 451 DPRINTF("failed to acquire crypto descriptors"); 452 espstat_inc(esps_crypto); 453 error = ENOBUFS; 454 goto drop; 455 } 456 457 if (esph) { 458 crda = &crp->crp_desc[0]; 459 crde = &crp->crp_desc[1]; 460 461 /* Authentication descriptor */ 462 crda->crd_skip = skip; 463 crda->crd_inject = m->m_pkthdr.len - alen; 464 465 crda->crd_alg = esph->type; 466 crda->crd_key = tdb->tdb_amxkey; 467 crda->crd_klen = tdb->tdb_amxkeylen * 8; 468 469 if ((tdb->tdb_wnd > 0) && (tdb->tdb_flags & TDBF_ESN)) { 470 esn = htonl(esn); 471 memcpy(crda->crd_esn, &esn, 4); 472 crda->crd_flags |= CRD_F_ESN; 473 } 474 475 if (espx && 476 (espx->type == CRYPTO_AES_GCM_16 || 477 espx->type == CRYPTO_CHACHA20_POLY1305)) 478 crda->crd_len = hlen - tdb->tdb_ivlen; 479 else 480 crda->crd_len = m->m_pkthdr.len - (skip + alen); 481 482 /* Copy the authenticator */ 483 m_copydata(m, m->m_pkthdr.len - alen, alen, abuf); 484 } else 485 crde = &crp->crp_desc[0]; 486 487 /* Crypto operation descriptor */ 488 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ 489 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_MPSAFE; 490 crp->crp_buf = (caddr_t)m; 491 crp->crp_sid = tdb->tdb_cryptoid; 492 493 /* Decryption descriptor */ 494 if (espx) { 495 crde->crd_skip = skip + hlen; 496 crde->crd_inject = skip + hlen - tdb->tdb_ivlen; 497 crde->crd_alg = espx->type; 498 crde->crd_key = tdb->tdb_emxkey; 499 crde->crd_klen = tdb->tdb_emxkeylen * 8; 500 /* XXX Rounds ? */ 501 502 if (crde->crd_alg == CRYPTO_AES_GMAC) 503 crde->crd_len = 0; 504 else 505 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 506 } 507 508 KERNEL_LOCK(); 509 while ((error = crypto_invoke(crp)) == EAGAIN) { 510 /* Reset the session ID */ 511 if (tdb->tdb_cryptoid != 0) 512 tdb->tdb_cryptoid = crp->crp_sid; 513 } 514 KERNEL_UNLOCK(); 515 if (error) { 516 DPRINTF("crypto error %d", error); 517 ipsecstat_inc(ipsec_noxform); 518 goto drop; 519 } 520 521 clen = crp->crp_olen; 522 523 /* Release the crypto descriptors */ 524 crypto_freereq(crp); 525 crp = NULL; 526 527 /* If authentication was performed, check now. */ 528 if (esph != NULL) { 529 /* Copy the authenticator from the packet */ 530 m_copydata(m, m->m_pkthdr.len - esph->authsize, 531 esph->authsize, aalg); 532 533 /* Verify authenticator */ 534 if (timingsafe_bcmp(abuf, aalg, esph->authsize)) { 535 DPRINTF("authentication failed for packet " 536 "in SA %s/%08x", 537 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 538 ntohl(tdb->tdb_spi)); 539 espstat_inc(esps_badauth); 540 error = -1; 541 goto drop; 542 } 543 544 /* Remove trailing authenticator */ 545 m_adj(m, -(esph->authsize)); 546 } 547 548 /* Replay window checking, if appropriate */ 549 if (tdb->tdb_wnd > 0) { 550 m_copydata(m, skip + sizeof(u_int32_t), sizeof(u_int32_t), 551 &btsx); 552 btsx = ntohl(btsx); 553 554 switch (checkreplaywindow(tdb, tdb->tdb_rpl, btsx, &esn, 1)) { 555 case 0: /* All's well */ 556 #if NPFSYNC > 0 557 pfsync_update_tdb(tdb,0); 558 #endif 559 break; 560 561 case 1: 562 DPRINTF("replay counter wrapped for SA %s/%08x", 563 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 564 ntohl(tdb->tdb_spi)); 565 espstat_inc(esps_wrap); 566 error = -1; 567 goto drop; 568 case 2: 569 DPRINTF("old packet received in SA %s/%08x", 570 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 571 ntohl(tdb->tdb_spi)); 572 espstat_inc(esps_replay); 573 error = -1; 574 goto drop; 575 case 3: 576 DPRINTF("duplicate packet received in SA %s/%08x", 577 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 578 ntohl(tdb->tdb_spi)); 579 espstat_inc(esps_replay); 580 error = -1; 581 goto drop; 582 default: 583 DPRINTF("bogus value from checkreplaywindow() " 584 "in SA %s/%08x", 585 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 586 ntohl(tdb->tdb_spi)); 587 espstat_inc(esps_replay); 588 error = -1; 589 goto drop; 590 } 591 } 592 593 /* Find beginning of ESP header */ 594 m1 = m_getptr(m, skip, &roff); 595 if (m1 == NULL) { 596 DPRINTF("bad mbuf chain, SA %s/%08x", 597 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 598 ntohl(tdb->tdb_spi)); 599 espstat_inc(esps_hdrops); 600 error = -1; 601 goto drop; 602 } 603 604 /* Remove the ESP header and IV from the mbuf. */ 605 if (roff == 0) { 606 /* The ESP header was conveniently at the beginning of the mbuf */ 607 m_adj(m1, hlen); 608 /* 609 * If m1 is the first mbuf, it has set M_PKTHDR and m_adj() 610 * has already adjusted the packet header length for us. 611 */ 612 if (m1 != m) 613 m->m_pkthdr.len -= hlen; 614 } else if (roff + hlen >= m1->m_len) { 615 int adjlen; 616 617 /* 618 * Part or all of the ESP header is at the end of this mbuf, so 619 * first let's remove the remainder of the ESP header from the 620 * beginning of the remainder of the mbuf chain, if any. 621 */ 622 if (roff + hlen > m1->m_len) { 623 adjlen = roff + hlen - m1->m_len; 624 625 /* Adjust the next mbuf by the remainder */ 626 m_adj(m1->m_next, adjlen); 627 628 /* The second mbuf is guaranteed not to have a pkthdr */ 629 m->m_pkthdr.len -= adjlen; 630 } 631 632 /* Now, let's unlink the mbuf chain for a second...*/ 633 mo = m1->m_next; 634 m1->m_next = NULL; 635 636 /* ...and trim the end of the first part of the chain...sick */ 637 adjlen = m1->m_len - roff; 638 m_adj(m1, -adjlen); 639 /* 640 * If m1 is the first mbuf, it has set M_PKTHDR and m_adj() 641 * has already adjusted the packet header length for us. 642 */ 643 if (m1 != m) 644 m->m_pkthdr.len -= adjlen; 645 646 /* Finally, let's relink */ 647 m1->m_next = mo; 648 } else { 649 /* 650 * The ESP header lies in the "middle" of the mbuf...do an 651 * overlapping copy of the remainder of the mbuf over the ESP 652 * header. 653 */ 654 memmove(mtod(m1, u_char *) + roff, 655 mtod(m1, u_char *) + roff + hlen, 656 m1->m_len - (roff + hlen)); 657 m1->m_len -= hlen; 658 m->m_pkthdr.len -= hlen; 659 } 660 661 /* Save the last three bytes of decrypted data */ 662 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); 663 664 /* Verify pad length */ 665 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { 666 DPRINTF("invalid padding length %d for packet in SA %s/%08x", 667 lastthree[1], 668 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 669 ntohl(tdb->tdb_spi)); 670 espstat_inc(esps_badilen); 671 error = -1; 672 goto drop; 673 } 674 675 /* Verify correct decryption by checking the last padding bytes */ 676 if ((lastthree[1] != lastthree[0]) && (lastthree[1] != 0)) { 677 DPRINTF("decryption failed for packet in SA %s/%08x", 678 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 679 ntohl(tdb->tdb_spi)); 680 espstat_inc(esps_badenc); 681 error = -1; 682 goto drop; 683 } 684 685 /* Trim the mbuf chain to remove the padding */ 686 m_adj(m, -(lastthree[1] + 2)); 687 688 /* Restore the Next Protocol field */ 689 m_copyback(m, protoff, sizeof(u_int8_t), lastthree + 2, M_NOWAIT); 690 691 /* Back to generic IPsec input processing */ 692 return ipsec_common_input_cb(mp, tdb, skip, protoff); 693 694 drop: 695 m_freemp(mp); 696 crypto_freereq(crp); 697 return error; 698 } 699 700 /* 701 * ESP output routine, called by ipsp_process_packet(). 702 */ 703 int 704 esp_output(struct mbuf *m, struct tdb *tdb, int skip, int protoff) 705 { 706 const struct enc_xform *espx = tdb->tdb_encalgxform; 707 const struct auth_hash *esph = tdb->tdb_authalgxform; 708 int ilen, olen, hlen, rlen, padding, blks, alen, roff, error; 709 uint64_t replay64; 710 uint32_t replay; 711 struct mbuf *mi, *mo = (struct mbuf *) NULL; 712 unsigned char *pad; 713 uint8_t prot; 714 #ifdef ENCDEBUG 715 char buf[INET6_ADDRSTRLEN]; 716 #endif 717 struct cryptodesc *crde = NULL, *crda = NULL; 718 struct cryptop *crp = NULL; 719 #if NBPFILTER > 0 720 struct ifnet *encif; 721 722 if ((encif = enc_getif(tdb->tdb_rdomain, tdb->tdb_tap)) != NULL) { 723 encif->if_opackets++; 724 encif->if_obytes += m->m_pkthdr.len; 725 726 if (encif->if_bpf) { 727 struct enchdr hdr; 728 729 memset(&hdr, 0, sizeof(hdr)); 730 731 hdr.af = tdb->tdb_dst.sa.sa_family; 732 hdr.spi = tdb->tdb_spi; 733 if (espx) 734 hdr.flags |= M_CONF; 735 if (esph) 736 hdr.flags |= M_AUTH; 737 738 bpf_mtap_hdr(encif->if_bpf, (char *)&hdr, 739 ENC_HDRLEN, m, BPF_DIRECTION_OUT); 740 } 741 } 742 #endif 743 744 hlen = 2 * sizeof(u_int32_t) + tdb->tdb_ivlen; 745 746 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ 747 if (espx) 748 blks = MAX(espx->blocksize, 4); 749 else 750 blks = 4; /* If no encryption, we have to be 4-byte aligned. */ 751 752 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; 753 754 alen = esph ? esph->authsize : 0; 755 espstat_inc(esps_output); 756 757 switch (tdb->tdb_dst.sa.sa_family) { 758 case AF_INET: 759 /* Check for IP maximum packet size violations. */ 760 if (skip + hlen + rlen + padding + alen > IP_MAXPACKET) { 761 DPRINTF("packet in SA %s/%08x got too big", 762 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 763 ntohl(tdb->tdb_spi)); 764 espstat_inc(esps_toobig); 765 error = EMSGSIZE; 766 goto drop; 767 } 768 break; 769 770 #ifdef INET6 771 case AF_INET6: 772 /* Check for IPv6 maximum packet size violations. */ 773 if (skip + hlen + rlen + padding + alen > IPV6_MAXPACKET) { 774 DPRINTF("acket in SA %s/%08x got too big", 775 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 776 ntohl(tdb->tdb_spi)); 777 espstat_inc(esps_toobig); 778 error = EMSGSIZE; 779 goto drop; 780 } 781 break; 782 #endif /* INET6 */ 783 784 default: 785 DPRINTF("unknown/unsupported protocol family %d, SA %s/%08x", 786 tdb->tdb_dst.sa.sa_family, 787 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 788 ntohl(tdb->tdb_spi)); 789 espstat_inc(esps_nopf); 790 error = EPFNOSUPPORT; 791 goto drop; 792 } 793 794 /* Update the counters. */ 795 tdb->tdb_cur_bytes += m->m_pkthdr.len - skip; 796 espstat_add(esps_obytes, m->m_pkthdr.len - skip); 797 798 /* Hard byte expiration. */ 799 if (tdb->tdb_flags & TDBF_BYTES && 800 tdb->tdb_cur_bytes >= tdb->tdb_exp_bytes) { 801 pfkeyv2_expire(tdb, SADB_EXT_LIFETIME_HARD); 802 tdb_delete(tdb); 803 error = EINVAL; 804 goto drop; 805 } 806 807 /* Soft byte expiration. */ 808 if (tdb->tdb_flags & TDBF_SOFT_BYTES && 809 tdb->tdb_cur_bytes >= tdb->tdb_soft_bytes) { 810 pfkeyv2_expire(tdb, SADB_EXT_LIFETIME_SOFT); 811 tdb->tdb_flags &= ~TDBF_SOFT_BYTES; /* Turn off checking. */ 812 } 813 814 /* 815 * Loop through mbuf chain; if we find a readonly mbuf, 816 * copy the packet. 817 */ 818 mi = m; 819 while (mi != NULL && !M_READONLY(mi)) 820 mi = mi->m_next; 821 822 if (mi != NULL) { 823 struct mbuf *n = m_dup_pkt(m, 0, M_DONTWAIT); 824 825 if (n == NULL) { 826 DPRINTF("bad mbuf chain, SA %s/%08x", 827 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 828 ntohl(tdb->tdb_spi)); 829 espstat_inc(esps_hdrops); 830 error = ENOBUFS; 831 goto drop; 832 } 833 834 m_freem(m); 835 m = n; 836 } 837 838 /* Inject ESP header. */ 839 mo = m_makespace(m, skip, hlen, &roff); 840 if (mo == NULL) { 841 DPRINTF("failed to inject ESP header for SA %s/%08x", 842 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 843 ntohl(tdb->tdb_spi)); 844 espstat_inc(esps_hdrops); 845 error = ENOBUFS; 846 goto drop; 847 } 848 849 /* Initialize ESP header. */ 850 memcpy(mtod(mo, caddr_t) + roff, (caddr_t) &tdb->tdb_spi, 851 sizeof(u_int32_t)); 852 replay64 = tdb->tdb_rpl++; /* used for both header and ESN */ 853 replay = htonl((u_int32_t)replay64); 854 memcpy(mtod(mo, caddr_t) + roff + sizeof(u_int32_t), (caddr_t) &replay, 855 sizeof(u_int32_t)); 856 857 #if NPFSYNC > 0 858 pfsync_update_tdb(tdb,1); 859 #endif 860 861 /* 862 * Add padding -- better to do it ourselves than use the crypto engine, 863 * although if/when we support compression, we'd have to do that. 864 */ 865 mo = m_makespace(m, m->m_pkthdr.len, padding + alen, &roff); 866 if (mo == NULL) { 867 DPRINTF("m_makespace() failed for SA %s/%08x", 868 ipsp_address(&tdb->tdb_dst, buf, sizeof(buf)), 869 ntohl(tdb->tdb_spi)); 870 espstat_inc(esps_hdrops); 871 error = ENOBUFS; 872 goto drop; 873 } 874 pad = mtod(mo, caddr_t) + roff; 875 876 /* Apply self-describing padding */ 877 for (ilen = 0; ilen < padding - 2; ilen++) 878 pad[ilen] = ilen + 1; 879 880 /* Fix padding length and Next Protocol in padding itself. */ 881 pad[padding - 2] = padding - 2; 882 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); 883 884 /* Fix Next Protocol in IPv4/IPv6 header. */ 885 prot = IPPROTO_ESP; 886 m_copyback(m, protoff, sizeof(u_int8_t), &prot, M_NOWAIT); 887 888 /* Get crypto descriptors. */ 889 crp = crypto_getreq(esph && espx ? 2 : 1); 890 if (crp == NULL) { 891 DPRINTF("failed to acquire crypto descriptors"); 892 espstat_inc(esps_crypto); 893 error = ENOBUFS; 894 goto drop; 895 } 896 897 if (espx) { 898 crde = &crp->crp_desc[0]; 899 crda = &crp->crp_desc[1]; 900 901 /* Encryption descriptor. */ 902 crde->crd_skip = skip + hlen; 903 crde->crd_flags = CRD_F_ENCRYPT | CRD_F_IV_EXPLICIT; 904 crde->crd_inject = skip + hlen - tdb->tdb_ivlen; 905 906 /* Encryption operation. */ 907 crde->crd_alg = espx->type; 908 crde->crd_key = tdb->tdb_emxkey; 909 crde->crd_klen = tdb->tdb_emxkeylen * 8; 910 /* XXX Rounds ? */ 911 912 if (crde->crd_alg == CRYPTO_AES_GMAC) 913 crde->crd_len = 0; 914 else 915 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); 916 917 /* GCM & friends just require a NONCE (non-repeating!) */ 918 if (espx->type == CRYPTO_AES_CTR || 919 espx->type == CRYPTO_AES_GCM_16 || 920 espx->type == CRYPTO_CHACHA20_POLY1305) 921 bcopy(&replay64, crde->crd_iv, sizeof(replay64)); 922 else 923 arc4random_buf(crde->crd_iv, espx->ivsize); 924 } else 925 crda = &crp->crp_desc[0]; 926 927 /* Crypto operation descriptor. */ 928 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 929 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_MPSAFE; 930 crp->crp_buf = (caddr_t)m; 931 crp->crp_sid = tdb->tdb_cryptoid; 932 933 if (esph) { 934 /* Authentication descriptor. */ 935 crda->crd_skip = skip; 936 crda->crd_inject = m->m_pkthdr.len - alen; 937 938 /* Authentication operation. */ 939 crda->crd_alg = esph->type; 940 crda->crd_key = tdb->tdb_amxkey; 941 crda->crd_klen = tdb->tdb_amxkeylen * 8; 942 943 if ((tdb->tdb_wnd > 0) && (tdb->tdb_flags & TDBF_ESN)) { 944 u_int32_t esn; 945 946 esn = htonl((u_int32_t)(replay64 >> 32)); 947 memcpy(crda->crd_esn, &esn, 4); 948 crda->crd_flags |= CRD_F_ESN; 949 } 950 951 if (espx && 952 (espx->type == CRYPTO_AES_GCM_16 || 953 espx->type == CRYPTO_CHACHA20_POLY1305)) 954 crda->crd_len = hlen - tdb->tdb_ivlen; 955 else 956 crda->crd_len = m->m_pkthdr.len - (skip + alen); 957 } 958 959 KERNEL_LOCK(); 960 while ((error = crypto_invoke(crp)) == EAGAIN) { 961 /* Reset the session ID */ 962 if (tdb->tdb_cryptoid != 0) 963 tdb->tdb_cryptoid = crp->crp_sid; 964 } 965 KERNEL_UNLOCK(); 966 if (error) { 967 DPRINTF("crypto error %d", error); 968 ipsecstat_inc(ipsec_noxform); 969 goto drop; 970 } 971 972 ilen = crp->crp_ilen; 973 olen = crp->crp_olen; 974 975 /* Release the crypto descriptors */ 976 crypto_freereq(crp); 977 978 /* Call the IPsec input callback. */ 979 error = ipsp_process_done(m, tdb); 980 if (error) 981 espstat_inc(esps_outfail); 982 return (error); 983 984 drop: 985 m_freem(m); 986 crypto_freereq(crp); 987 return error; 988 } 989 990 #define SEEN_SIZE howmany(TDB_REPLAYMAX, 32) 991 992 /* 993 * return 0 on success 994 * return 1 for counter == 0 995 * return 2 for very old packet 996 * return 3 for packet within current window but already received 997 */ 998 int 999 checkreplaywindow(struct tdb *tdb, u_int64_t t, u_int32_t seq, u_int32_t *seqh, 1000 int commit) 1001 { 1002 u_int32_t tl, th, wl; 1003 u_int32_t packet, window = TDB_REPLAYMAX - TDB_REPLAYWASTE; 1004 int idx, esn = tdb->tdb_flags & TDBF_ESN; 1005 1006 tl = (u_int32_t)t; 1007 th = (u_int32_t)(t >> 32); 1008 1009 /* Zero SN is not allowed */ 1010 if ((esn && seq == 0 && tl <= AH_HMAC_INITIAL_RPL && th == 0) || 1011 (!esn && seq == 0)) 1012 return (1); 1013 1014 if (th == 0 && tl < window) 1015 window = tl; 1016 /* Current replay window starts here */ 1017 wl = tl - window + 1; 1018 1019 idx = (seq % TDB_REPLAYMAX) / 32; 1020 packet = 1 << (31 - (seq & 31)); 1021 1022 /* 1023 * We keep the high part intact when: 1024 * 1) the SN is within [wl, 0xffffffff] and the whole window is 1025 * within one subspace; 1026 * 2) the SN is within [0, wl) and window spans two subspaces. 1027 */ 1028 if ((tl >= window - 1 && seq >= wl) || 1029 (tl < window - 1 && seq < wl)) { 1030 *seqh = th; 1031 if (seq > tl) { 1032 if (commit) { 1033 if (seq - tl > window) 1034 memset(tdb->tdb_seen, 0, 1035 sizeof(tdb->tdb_seen)); 1036 else { 1037 int i = (tl % TDB_REPLAYMAX) / 32; 1038 1039 while (i != idx) { 1040 i = (i + 1) % SEEN_SIZE; 1041 tdb->tdb_seen[i] = 0; 1042 } 1043 } 1044 tdb->tdb_seen[idx] |= packet; 1045 tdb->tdb_rpl = ((u_int64_t)*seqh << 32) | seq; 1046 } 1047 } else { 1048 if (tl - seq >= window) 1049 return (2); 1050 if (tdb->tdb_seen[idx] & packet) 1051 return (3); 1052 if (commit) 1053 tdb->tdb_seen[idx] |= packet; 1054 } 1055 return (0); 1056 } 1057 1058 /* Can't wrap if not doing ESN */ 1059 if (!esn) 1060 return (2); 1061 1062 /* 1063 * (3) SN is within [wl, 0xffffffff] and wl is within 1064 * (0xffffffff-window+1, 0xffffffff]. 1065 * This means we got a SN which is within our replay window, 1066 * but in the previous subspace. 1067 */ 1068 if (tl < window - 1 && seq >= wl) { 1069 if (tdb->tdb_seen[idx] & packet) 1070 return (3); 1071 *seqh = th - 1; 1072 if (commit) 1073 tdb->tdb_seen[idx] |= packet; 1074 return (0); 1075 } 1076 1077 /* 1078 * (4) SN has wrapped and the last authenticated SN is in the old 1079 * subspace. 1080 */ 1081 *seqh = th + 1; 1082 if (*seqh == 0) /* Don't let high bit to wrap */ 1083 return (1); 1084 if (commit) { 1085 if (seq - tl > window) 1086 memset(tdb->tdb_seen, 0, sizeof(tdb->tdb_seen)); 1087 else { 1088 int i = (tl % TDB_REPLAYMAX) / 32; 1089 1090 while (i != idx) { 1091 i = (i + 1) % SEEN_SIZE; 1092 tdb->tdb_seen[i] = 0; 1093 } 1094 } 1095 tdb->tdb_seen[idx] |= packet; 1096 tdb->tdb_rpl = ((u_int64_t)*seqh << 32) | seq; 1097 } 1098 1099 return (0); 1100 } 1101