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_PCPUSTAT_DEFINE(struct espstat, espstat);
85 VNET_PCPUSTAT_SYSINIT(espstat);
86
87 #ifdef VIMAGE
88 VNET_PCPUSTAT_SYSUNINIT(espstat);
89 #endif /* VIMAGE */
90
91 SYSCTL_DECL(_net_inet_esp);
92 SYSCTL_INT(_net_inet_esp, OID_AUTO, esp_enable,
93 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(esp_enable), 0, "");
94 SYSCTL_VNET_PCPUSTAT(_net_inet_esp, IPSECCTL_STATS, stats,
95 struct espstat, espstat,
96 "ESP statistics (struct espstat, netipsec/esp_var.h");
97
98 static struct timeval deswarn, blfwarn, castwarn, camelliawarn, tdeswarn;
99
100 static int esp_input_cb(struct cryptop *op);
101 static int esp_output_cb(struct cryptop *crp);
102
103 size_t
104 esp_hdrsiz(struct secasvar *sav)
105 {
106 size_t size;
107
108 if (sav != NULL) {
109 /*XXX not right for null algorithm--does it matter??*/
110 IPSEC_ASSERT(sav->tdb_encalgxform != NULL,
111 ("SA with null xform"));
112 if (sav->flags & SADB_X_EXT_OLD)
113 size = sizeof (struct esp);
114 else
115 size = sizeof (struct newesp);
116 size += sav->tdb_encalgxform->blocksize + 9;
117 /*XXX need alg check???*/
118 if (sav->tdb_authalgxform != NULL && sav->replay)
119 size += ah_hdrsiz(sav);
120 } else {
121 /*
122 * base header size
123 * + max iv length for CBC mode
124 * + max pad length
125 * + sizeof (pad length field)
126 * + sizeof (next header field)
127 * + max icv supported.
128 */
129 size = sizeof (struct newesp) + EALG_MAX_BLOCK_LEN + 9 + 16;
130 }
131 return size;
132 }
133
134 /*
135 * esp_init() is called when an SPI is being set up.
136 */
137 static int
138 esp_init(struct secasvar *sav, struct xformsw *xsp)
139 {
140 const struct enc_xform *txform;
141 struct cryptoini cria, crie;
142 int keylen;
143 int error;
144
145 txform = enc_algorithm_lookup(sav->alg_enc);
146 if (txform == NULL) {
147 DPRINTF(("%s: unsupported encryption algorithm %d\n",
148 __func__, sav->alg_enc));
149 return EINVAL;
150 }
151 if (sav->key_enc == NULL) {
152 DPRINTF(("%s: no encoding key for %s algorithm\n",
153 __func__, txform->name));
154 return EINVAL;
155 }
156 if ((sav->flags & (SADB_X_EXT_OLD | SADB_X_EXT_IV4B)) ==
157 SADB_X_EXT_IV4B) {
158 DPRINTF(("%s: 4-byte IV not supported with protocol\n",
159 __func__));
160 return EINVAL;
161 }
162
163 switch (sav->alg_enc) {
164 case SADB_EALG_DESCBC:
165 if (ratecheck(&deswarn, &ipsec_warn_interval))
166 gone_in(13, "DES cipher for IPsec");
167 break;
168 case SADB_EALG_3DESCBC:
169 if (ratecheck(&tdeswarn, &ipsec_warn_interval))
170 gone_in(13, "3DES cipher for IPsec");
171 break;
172 case SADB_X_EALG_BLOWFISHCBC:
173 if (ratecheck(&blfwarn, &ipsec_warn_interval))
174 gone_in(13, "Blowfish cipher for IPsec");
175 break;
176 case SADB_X_EALG_CAST128CBC:
177 if (ratecheck(&castwarn, &ipsec_warn_interval))
178 gone_in(13, "CAST cipher for IPsec");
179 break;
180 case SADB_X_EALG_CAMELLIACBC:
181 if (ratecheck(&camelliawarn, &ipsec_warn_interval))
182 gone_in(13, "Camellia cipher for IPsec");
183 break;
184 }
185
186 /* subtract off the salt, RFC4106, 8.1 and RFC3686, 5.1 */
187 keylen = _KEYLEN(sav->key_enc) - SAV_ISCTRORGCM(sav) * 4;
188 if (txform->minkey > keylen || keylen > txform->maxkey) {
189 DPRINTF(("%s: invalid key length %u, must be in the range "
190 "[%u..%u] for algorithm %s\n", __func__,
191 keylen, txform->minkey, txform->maxkey,
192 txform->name));
193 return EINVAL;
194 }
195
196 if (SAV_ISCTRORGCM(sav))
197 sav->ivlen = 8; /* RFC4106 3.1 and RFC3686 3.1 */
198 else
199 sav->ivlen = txform->ivsize;
200
201 /*
202 * Setup AH-related state.
203 */
204 if (sav->alg_auth != 0) {
205 error = ah_init0(sav, xsp, &cria);
206 if (error)
207 return error;
208 }
209
210 /* NB: override anything set in ah_init0 */
211 sav->tdb_xform = xsp;
212 sav->tdb_encalgxform = txform;
213
214 /*
215 * Whenever AES-GCM is used for encryption, one
216 * of the AES authentication algorithms is chosen
217 * as well, based on the key size.
218 */
219 if (sav->alg_enc == SADB_X_EALG_AESGCM16) {
220 switch (keylen) {
221 case AES_128_GMAC_KEY_LEN:
222 sav->alg_auth = SADB_X_AALG_AES128GMAC;
223 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_128;
224 break;
225 case AES_192_GMAC_KEY_LEN:
226 sav->alg_auth = SADB_X_AALG_AES192GMAC;
227 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_192;
228 break;
229 case AES_256_GMAC_KEY_LEN:
230 sav->alg_auth = SADB_X_AALG_AES256GMAC;
231 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_256;
232 break;
233 default:
234 DPRINTF(("%s: invalid key length %u"
235 "for algorithm %s\n", __func__,
236 keylen, txform->name));
237 return EINVAL;
238 }
239 bzero(&cria, sizeof(cria));
240 cria.cri_alg = sav->tdb_authalgxform->type;
241 cria.cri_key = sav->key_enc->key_data;
242 cria.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISGCM(sav) * 32;
243 }
244
245 /* Initialize crypto session. */
246 bzero(&crie, sizeof(crie));
247 crie.cri_alg = sav->tdb_encalgxform->type;
248 crie.cri_key = sav->key_enc->key_data;
249 crie.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISCTRORGCM(sav) * 32;
250
251 if (sav->tdb_authalgxform && sav->tdb_encalgxform) {
252 /* init both auth & enc */
253 crie.cri_next = &cria;
254 error = crypto_newsession(&sav->tdb_cryptoid,
255 &crie, V_crypto_support);
256 } else if (sav->tdb_encalgxform) {
257 error = crypto_newsession(&sav->tdb_cryptoid,
258 &crie, V_crypto_support);
259 } else if (sav->tdb_authalgxform) {
260 error = crypto_newsession(&sav->tdb_cryptoid,
261 &cria, V_crypto_support);
262 } else {
263 /* XXX cannot happen? */
264 DPRINTF(("%s: no encoding OR authentication xform!\n",
265 __func__));
266 error = EINVAL;
267 }
268 return error;
269 }
270
271 /*
272 * Paranoia.
273 */
274 static int
275 esp_zeroize(struct secasvar *sav)
276 {
277 /* NB: ah_zerorize free's the crypto session state */
278 int error = ah_zeroize(sav);
279
280 if (sav->key_enc)
281 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc));
282 sav->tdb_encalgxform = NULL;
283 sav->tdb_xform = NULL;
284 return error;
285 }
286
287 /*
288 * ESP input processing, called (eventually) through the protocol switch.
289 */
290 static int
291 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
292 {
293 IPSEC_DEBUG_DECLARE(char buf[128]);
294 const struct auth_hash *esph;
295 const struct enc_xform *espx;
296 struct xform_data *xd;
297 struct cryptodesc *crde;
298 struct cryptop *crp;
299 struct newesp *esp;
300 uint8_t *ivp;
301 crypto_session_t cryptoid;
302 int alen, error, hlen, plen;
303
304 IPSEC_ASSERT(sav != NULL, ("null SA"));
305 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform"));
306
307 error = EINVAL;
308 /* Valid IP Packet length ? */
309 if ( (skip&3) || (m->m_pkthdr.len&3) ){
310 DPRINTF(("%s: misaligned packet, skip %u pkt len %u",
311 __func__, skip, m->m_pkthdr.len));
312 ESPSTAT_INC(esps_badilen);
313 goto bad;
314 }
315
316 if (m->m_len < skip + sizeof(*esp)) {
317 m = m_pullup(m, skip + sizeof(*esp));
318 if (m == NULL) {
319 DPRINTF(("%s: cannot pullup header\n", __func__));
320 ESPSTAT_INC(esps_hdrops); /*XXX*/
321 error = ENOBUFS;
322 goto bad;
323 }
324 }
325 esp = (struct newesp *)(mtod(m, caddr_t) + skip);
326
327 esph = sav->tdb_authalgxform;
328 espx = sav->tdb_encalgxform;
329
330 /* Determine the ESP header and auth length */
331 if (sav->flags & SADB_X_EXT_OLD)
332 hlen = sizeof (struct esp) + sav->ivlen;
333 else
334 hlen = sizeof (struct newesp) + sav->ivlen;
335
336 alen = xform_ah_authsize(esph);
337
338 /*
339 * Verify payload length is multiple of encryption algorithm
340 * block size.
341 *
342 * NB: This works for the null algorithm because the blocksize
343 * is 4 and all packets must be 4-byte aligned regardless
344 * of the algorithm.
345 */
346 plen = m->m_pkthdr.len - (skip + hlen + alen);
347 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) {
348 DPRINTF(("%s: payload of %d octets not a multiple of %d octets,"
349 " SA %s/%08lx\n", __func__, plen, espx->blocksize,
350 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
351 (u_long)ntohl(sav->spi)));
352 ESPSTAT_INC(esps_badilen);
353 goto bad;
354 }
355
356 /*
357 * Check sequence number.
358 */
359 SECASVAR_LOCK(sav);
360 if (esph != NULL && sav->replay != NULL && sav->replay->wsize != 0) {
361 if (ipsec_chkreplay(ntohl(esp->esp_seq), sav) == 0) {
362 SECASVAR_UNLOCK(sav);
363 DPRINTF(("%s: packet replay check for %s\n", __func__,
364 ipsec_sa2str(sav, buf, sizeof(buf))));
365 ESPSTAT_INC(esps_replay);
366 error = EACCES;
367 goto bad;
368 }
369 }
370 cryptoid = sav->tdb_cryptoid;
371 SECASVAR_UNLOCK(sav);
372
373 /* Update the counters */
374 ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen));
375
376 /* Get crypto descriptors */
377 crp = crypto_getreq(esph && espx ? 2 : 1);
378 if (crp == NULL) {
379 DPRINTF(("%s: failed to acquire crypto descriptors\n",
380 __func__));
381 ESPSTAT_INC(esps_crypto);
382 error = ENOBUFS;
383 goto bad;
384 }
385
386 /* Get IPsec-specific opaque pointer */
387 xd = malloc(sizeof(*xd) + alen, M_XDATA, M_NOWAIT | M_ZERO);
388 if (xd == NULL) {
389 DPRINTF(("%s: failed to allocate xform_data\n", __func__));
390 ESPSTAT_INC(esps_crypto);
391 crypto_freereq(crp);
392 error = ENOBUFS;
393 goto bad;
394 }
395
396 if (esph != NULL) {
397 struct cryptodesc *crda = crp->crp_desc;
398
399 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor"));
400
401 /* Authentication descriptor */
402 crda->crd_skip = skip;
403 if (SAV_ISGCM(sav))
404 crda->crd_len = 8; /* RFC4106 5, SPI + SN */
405 else
406 crda->crd_len = m->m_pkthdr.len - (skip + alen);
407 crda->crd_inject = m->m_pkthdr.len - alen;
408
409 crda->crd_alg = esph->type;
410
411 /* Copy the authenticator */
412 m_copydata(m, m->m_pkthdr.len - alen, alen,
413 (caddr_t) (xd + 1));
414
415 /* Chain authentication request */
416 crde = crda->crd_next;
417 } else {
418 crde = crp->crp_desc;
419 }
420
421 /* Crypto operation descriptor */
422 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */
423 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
424 if (V_async_crypto)
425 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER;
426 crp->crp_buf = (caddr_t) m;
427 crp->crp_callback = esp_input_cb;
428 crp->crp_session = cryptoid;
429 crp->crp_opaque = (caddr_t) xd;
430
431 /* These are passed as-is to the callback */
432 xd->sav = sav;
433 xd->protoff = protoff;
434 xd->skip = skip;
435 xd->cryptoid = cryptoid;
436 xd->vnet = curvnet;
437
438 /* Decryption descriptor */
439 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor"));
440 crde->crd_skip = skip + hlen;
441 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
442 crde->crd_inject = skip + hlen - sav->ivlen;
443
444 if (SAV_ISCTRORGCM(sav)) {
445 ivp = &crde->crd_iv[0];
446
447 /* GCM IV Format: RFC4106 4 */
448 /* CTR IV Format: RFC3686 4 */
449 /* Salt is last four bytes of key, RFC4106 8.1 */
450 /* Nonce is last four bytes of key, RFC3686 5.1 */
451 memcpy(ivp, sav->key_enc->key_data +
452 _KEYLEN(sav->key_enc) - 4, 4);
453
454 if (SAV_ISCTR(sav)) {
455 /* Initial block counter is 1, RFC3686 4 */
456 be32enc(&ivp[sav->ivlen + 4], 1);
457 }
458
459 m_copydata(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]);
460 crde->crd_flags |= CRD_F_IV_EXPLICIT;
461 }
462
463 crde->crd_alg = espx->type;
464
465 return (crypto_dispatch(crp));
466 bad:
467 m_freem(m);
468 key_freesav(&sav);
469 return (error);
470 }
471
472 /*
473 * ESP input callback from the crypto driver.
474 */
475 static int
476 esp_input_cb(struct cryptop *crp)
477 {
478 IPSEC_DEBUG_DECLARE(char buf[128]);
479 u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN];
480 const struct auth_hash *esph;
481 struct mbuf *m;
482 struct cryptodesc *crd;
483 struct xform_data *xd;
484 struct secasvar *sav;
485 struct secasindex *saidx;
486 caddr_t ptr;
487 crypto_session_t cryptoid;
488 int hlen, skip, protoff, error, alen;
489
490 crd = crp->crp_desc;
491 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!"));
492
493 m = (struct mbuf *) crp->crp_buf;
494 xd = (struct xform_data *) 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 ESPSTAT_INC(esps_noxform);
514 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
515 error = crp->crp_etype;
516 goto bad;
517 }
518
519 /* Shouldn't happen... */
520 if (m == NULL) {
521 ESPSTAT_INC(esps_crypto);
522 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
523 error = EINVAL;
524 goto bad;
525 }
526 ESPSTAT_INC(esps_hist[sav->alg_enc]);
527
528 /* If authentication was performed, check now. */
529 if (esph != NULL) {
530 alen = xform_ah_authsize(esph);
531 AHSTAT_INC(ahs_hist[sav->alg_auth]);
532 /* Copy the authenticator from the packet */
533 m_copydata(m, m->m_pkthdr.len - alen, alen, aalg);
534 ptr = (caddr_t) (xd + 1);
535
536 /* Verify authenticator */
537 if (timingsafe_bcmp(ptr, aalg, alen) != 0) {
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 crypto_freereq(crp), crp = NULL;
554
555 /*
556 * Packet is now decrypted.
557 */
558 m->m_flags |= M_DECRYPTED;
559
560 /*
561 * Update replay sequence number, if appropriate.
562 */
563 if (sav->replay) {
564 u_int32_t seq;
565
566 m_copydata(m, skip + offsetof(struct newesp, esp_seq),
567 sizeof (seq), (caddr_t) &seq);
568 SECASVAR_LOCK(sav);
569 if (ipsec_updatereplay(ntohl(seq), sav)) {
570 SECASVAR_UNLOCK(sav);
571 DPRINTF(("%s: packet replay check for %s\n", __func__,
572 ipsec_sa2str(sav, buf, sizeof(buf))));
573 ESPSTAT_INC(esps_replay);
574 error = EACCES;
575 goto bad;
576 }
577 SECASVAR_UNLOCK(sav);
578 }
579
580 /* Determine the ESP header length */
581 if (sav->flags & SADB_X_EXT_OLD)
582 hlen = sizeof (struct esp) + sav->ivlen;
583 else
584 hlen = sizeof (struct newesp) + sav->ivlen;
585
586 /* Remove the ESP header and IV from the mbuf. */
587 error = m_striphdr(m, skip, hlen);
588 if (error) {
589 ESPSTAT_INC(esps_hdrops);
590 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__,
591 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
592 (u_long) ntohl(sav->spi)));
593 goto bad;
594 }
595
596 /* Save the last three bytes of decrypted data */
597 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree);
598
599 /* Verify pad length */
600 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) {
601 ESPSTAT_INC(esps_badilen);
602 DPRINTF(("%s: invalid padding length %d for %u byte packet "
603 "in SA %s/%08lx\n", __func__, lastthree[1],
604 m->m_pkthdr.len - skip,
605 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
606 (u_long) ntohl(sav->spi)));
607 error = EINVAL;
608 goto bad;
609 }
610
611 /* Verify correct decryption by checking the last padding bytes */
612 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) {
613 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) {
614 ESPSTAT_INC(esps_badenc);
615 DPRINTF(("%s: decryption failed for packet in "
616 "SA %s/%08lx\n", __func__, ipsec_address(
617 &sav->sah->saidx.dst, buf, sizeof(buf)),
618 (u_long) ntohl(sav->spi)));
619 error = EINVAL;
620 goto bad;
621 }
622 }
623
624 /*
625 * RFC4303 2.6:
626 * Silently drop packet if next header field is IPPROTO_NONE.
627 */
628 if (lastthree[2] == IPPROTO_NONE)
629 goto bad;
630
631 /* Trim the mbuf chain to remove trailing authenticator and padding */
632 m_adj(m, -(lastthree[1] + 2));
633
634 /* Restore the Next Protocol field */
635 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2);
636
637 switch (saidx->dst.sa.sa_family) {
638 #ifdef INET6
639 case AF_INET6:
640 error = ipsec6_common_input_cb(m, sav, skip, protoff);
641 break;
642 #endif
643 #ifdef INET
644 case AF_INET:
645 error = ipsec4_common_input_cb(m, sav, skip, protoff);
646 break;
647 #endif
648 default:
649 panic("%s: Unexpected address family: %d saidx=%p", __func__,
650 saidx->dst.sa.sa_family, saidx);
651 }
652 CURVNET_RESTORE();
653 return error;
654 bad:
655 CURVNET_RESTORE();
656 if (sav != NULL)
657 key_freesav(&sav);
658 if (m != NULL)
659 m_freem(m);
660 if (xd != NULL)
661 free(xd, M_XDATA);
662 if (crp != NULL)
663 crypto_freereq(crp);
664 return error;
665 }
666 /*
667 * ESP output routine, called by ipsec[46]_perform_request().
668 */
669 static int
670 esp_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav,
671 u_int idx, int skip, int protoff)
672 {
673 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
674 struct cryptodesc *crde = NULL, *crda = NULL;
675 struct cryptop *crp;
676 const struct auth_hash *esph;
677 const struct enc_xform *espx;
678 struct mbuf *mo = NULL;
679 struct xform_data *xd;
680 struct secasindex *saidx;
681 unsigned char *pad;
682 uint8_t *ivp;
683 uint64_t cntr;
684 crypto_session_t cryptoid;
685 int hlen, rlen, padding, blks, alen, i, roff;
686 int error, maxpacketsize;
687 uint8_t prot;
688
689 IPSEC_ASSERT(sav != NULL, ("null SA"));
690 esph = sav->tdb_authalgxform;
691 espx = sav->tdb_encalgxform;
692 IPSEC_ASSERT(espx != NULL, ("null encoding xform"));
693
694 if (sav->flags & SADB_X_EXT_OLD)
695 hlen = sizeof (struct esp) + sav->ivlen;
696 else
697 hlen = sizeof (struct newesp) + sav->ivlen;
698
699 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */
700 /*
701 * RFC4303 2.4 Requires 4 byte alignment.
702 */
703 blks = MAX(4, espx->blocksize); /* Cipher blocksize */
704
705 /* XXX clamp padding length a la KAME??? */
706 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;
707
708 alen = xform_ah_authsize(esph);
709
710 ESPSTAT_INC(esps_output);
711
712 saidx = &sav->sah->saidx;
713 /* Check for maximum packet size violations. */
714 switch (saidx->dst.sa.sa_family) {
715 #ifdef INET
716 case AF_INET:
717 maxpacketsize = IP_MAXPACKET;
718 break;
719 #endif /* INET */
720 #ifdef INET6
721 case AF_INET6:
722 maxpacketsize = IPV6_MAXPACKET;
723 break;
724 #endif /* INET6 */
725 default:
726 DPRINTF(("%s: unknown/unsupported protocol "
727 "family %d, SA %s/%08lx\n", __func__,
728 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst,
729 buf, sizeof(buf)), (u_long) ntohl(sav->spi)));
730 ESPSTAT_INC(esps_nopf);
731 error = EPFNOSUPPORT;
732 goto bad;
733 }
734 /*
735 DPRINTF(("%s: skip %d hlen %d rlen %d padding %d alen %d blksd %d\n",
736 __func__, skip, hlen, rlen, padding, alen, blks)); */
737 if (skip + hlen + rlen + padding + alen > maxpacketsize) {
738 DPRINTF(("%s: packet in SA %s/%08lx got too big "
739 "(len %u, max len %u)\n", __func__,
740 ipsec_address(&saidx->dst, buf, sizeof(buf)),
741 (u_long) ntohl(sav->spi),
742 skip + hlen + rlen + padding + alen, maxpacketsize));
743 ESPSTAT_INC(esps_toobig);
744 error = EMSGSIZE;
745 goto bad;
746 }
747
748 /* Update the counters. */
749 ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip);
750
751 m = m_unshare(m, M_NOWAIT);
752 if (m == NULL) {
753 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__,
754 ipsec_address(&saidx->dst, buf, sizeof(buf)),
755 (u_long) ntohl(sav->spi)));
756 ESPSTAT_INC(esps_hdrops);
757 error = ENOBUFS;
758 goto bad;
759 }
760
761 /* Inject ESP header. */
762 mo = m_makespace(m, skip, hlen, &roff);
763 if (mo == NULL) {
764 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n",
765 __func__, hlen, ipsec_address(&saidx->dst, buf,
766 sizeof(buf)), (u_long) ntohl(sav->spi)));
767 ESPSTAT_INC(esps_hdrops); /* XXX diffs from openbsd */
768 error = ENOBUFS;
769 goto bad;
770 }
771
772 /* Initialize ESP header. */
773 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff,
774 sizeof(uint32_t));
775 SECASVAR_LOCK(sav);
776 if (sav->replay) {
777 uint32_t replay;
778
779 #ifdef REGRESSION
780 /* Emulate replay attack when ipsec_replay is TRUE. */
781 if (!V_ipsec_replay)
782 #endif
783 sav->replay->count++;
784 replay = htonl(sav->replay->count);
785
786 bcopy((caddr_t) &replay, mtod(mo, caddr_t) + roff +
787 sizeof(uint32_t), sizeof(uint32_t));
788 }
789 cryptoid = sav->tdb_cryptoid;
790 if (SAV_ISCTRORGCM(sav))
791 cntr = sav->cntr++;
792 SECASVAR_UNLOCK(sav);
793
794 /*
795 * Add padding -- better to do it ourselves than use the crypto engine,
796 * although if/when we support compression, we'd have to do that.
797 */
798 pad = (u_char *) m_pad(m, padding + alen);
799 if (pad == NULL) {
800 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__,
801 ipsec_address(&saidx->dst, buf, sizeof(buf)),
802 (u_long) ntohl(sav->spi)));
803 m = NULL; /* NB: free'd by m_pad */
804 error = ENOBUFS;
805 goto bad;
806 }
807
808 /*
809 * Add padding: random, zero, or self-describing.
810 * XXX catch unexpected setting
811 */
812 switch (sav->flags & SADB_X_EXT_PMASK) {
813 case SADB_X_EXT_PRAND:
814 arc4random_buf(pad, padding - 2);
815 break;
816 case SADB_X_EXT_PZERO:
817 bzero(pad, padding - 2);
818 break;
819 case SADB_X_EXT_PSEQ:
820 for (i = 0; i < padding - 2; i++)
821 pad[i] = i+1;
822 break;
823 }
824
825 /* Fix padding length and Next Protocol in padding itself. */
826 pad[padding - 2] = padding - 2;
827 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1);
828
829 /* Fix Next Protocol in IPv4/IPv6 header. */
830 prot = IPPROTO_ESP;
831 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot);
832
833 /* Get crypto descriptors. */
834 crp = crypto_getreq(esph != NULL ? 2 : 1);
835 if (crp == NULL) {
836 DPRINTF(("%s: failed to acquire crypto descriptors\n",
837 __func__));
838 ESPSTAT_INC(esps_crypto);
839 error = ENOBUFS;
840 goto bad;
841 }
842
843 /* IPsec-specific opaque crypto info. */
844 xd = malloc(sizeof(struct xform_data), M_XDATA, M_NOWAIT | M_ZERO);
845 if (xd == NULL) {
846 crypto_freereq(crp);
847 DPRINTF(("%s: failed to allocate xform_data\n", __func__));
848 ESPSTAT_INC(esps_crypto);
849 error = ENOBUFS;
850 goto bad;
851 }
852
853 crde = crp->crp_desc;
854 crda = crde->crd_next;
855
856 /* Encryption descriptor. */
857 crde->crd_skip = skip + hlen;
858 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
859 crde->crd_flags = CRD_F_ENCRYPT;
860 crde->crd_inject = skip + hlen - sav->ivlen;
861
862 /* Encryption operation. */
863 crde->crd_alg = espx->type;
864 if (SAV_ISCTRORGCM(sav)) {
865 ivp = &crde->crd_iv[0];
866
867 /* GCM IV Format: RFC4106 4 */
868 /* CTR IV Format: RFC3686 4 */
869 /* Salt is last four bytes of key, RFC4106 8.1 */
870 /* Nonce is last four bytes of key, RFC3686 5.1 */
871 memcpy(ivp, sav->key_enc->key_data +
872 _KEYLEN(sav->key_enc) - 4, 4);
873 be64enc(&ivp[4], cntr);
874 if (SAV_ISCTR(sav)) {
875 /* Initial block counter is 1, RFC3686 4 */
876 /* XXXAE: should we use this only for first packet? */
877 be32enc(&ivp[sav->ivlen + 4], 1);
878 }
879
880 m_copyback(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]);
881 crde->crd_flags |= CRD_F_IV_EXPLICIT|CRD_F_IV_PRESENT;
882 }
883
884 /* Callback parameters */
885 xd->sp = sp;
886 xd->sav = sav;
887 xd->idx = idx;
888 xd->cryptoid = cryptoid;
889 xd->vnet = curvnet;
890
891 /* Crypto operation descriptor. */
892 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
893 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
894 if (V_async_crypto)
895 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER;
896 crp->crp_buf = (caddr_t) m;
897 crp->crp_callback = esp_output_cb;
898 crp->crp_opaque = (caddr_t) xd;
899 crp->crp_session = cryptoid;
900
901 if (esph) {
902 /* Authentication descriptor. */
903 crda->crd_alg = esph->type;
904 crda->crd_skip = skip;
905 if (SAV_ISGCM(sav))
906 crda->crd_len = 8; /* RFC4106 5, SPI + SN */
907 else
908 crda->crd_len = m->m_pkthdr.len - (skip + alen);
909 crda->crd_inject = m->m_pkthdr.len - alen;
910 }
911
912 return crypto_dispatch(crp);
913 bad:
914 if (m)
915 m_freem(m);
916 key_freesav(&sav);
917 key_freesp(&sp);
918 return (error);
919 }
920 /*
921 * ESP output callback from the crypto driver.
922 */
923 static int
924 esp_output_cb(struct cryptop *crp)
925 {
926 struct xform_data *xd;
927 struct secpolicy *sp;
928 struct secasvar *sav;
929 struct mbuf *m;
930 crypto_session_t cryptoid;
931 u_int idx;
932 int error;
933
934 xd = (struct xform_data *) crp->crp_opaque;
935 CURVNET_SET(xd->vnet);
936 m = (struct mbuf *) crp->crp_buf;
937 sp = xd->sp;
938 sav = xd->sav;
939 idx = xd->idx;
940 cryptoid = xd->cryptoid;
941
942 /* Check for crypto errors. */
943 if (crp->crp_etype) {
944 if (crp->crp_etype == EAGAIN) {
945 /* Reset the session ID */
946 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0)
947 crypto_freesession(cryptoid);
948 xd->cryptoid = crp->crp_session;
949 CURVNET_RESTORE();
950 return (crypto_dispatch(crp));
951 }
952 ESPSTAT_INC(esps_noxform);
953 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
954 error = crp->crp_etype;
955 m_freem(m);
956 goto bad;
957 }
958
959 /* Shouldn't happen... */
960 if (m == NULL) {
961 ESPSTAT_INC(esps_crypto);
962 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
963 error = EINVAL;
964 goto bad;
965 }
966 free(xd, M_XDATA);
967 crypto_freereq(crp);
968 ESPSTAT_INC(esps_hist[sav->alg_enc]);
969 if (sav->tdb_authalgxform != NULL)
970 AHSTAT_INC(ahs_hist[sav->alg_auth]);
971
972 #ifdef REGRESSION
973 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
974 if (V_ipsec_integrity) {
975 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN];
976 const struct auth_hash *esph;
977
978 /*
979 * Corrupt HMAC if we want to test integrity verification of
980 * the other side.
981 */
982 esph = sav->tdb_authalgxform;
983 if (esph != NULL) {
984 int alen;
985
986 alen = xform_ah_authsize(esph);
987 m_copyback(m, m->m_pkthdr.len - alen,
988 alen, ipseczeroes);
989 }
990 }
991 #endif
992
993 /* NB: m is reclaimed by ipsec_process_done. */
994 error = ipsec_process_done(m, sp, sav, idx);
995 CURVNET_RESTORE();
996 return (error);
997 bad:
998 CURVNET_RESTORE();
999 free(xd, M_XDATA);
1000 crypto_freereq(crp);
1001 key_freesav(&sav);
1002 key_freesp(&sp);
1003 return (error);
1004 }
1005
1006 static struct xformsw esp_xformsw = {
1007 .xf_type = XF_ESP,
1008 .xf_name = "IPsec ESP",
1009 .xf_init = esp_init,
1010 .xf_zeroize = esp_zeroize,
1011 .xf_input = esp_input,
1012 .xf_output = esp_output,
1013 };
1014
1015 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
1016 xform_attach, &esp_xformsw);
1017 SYSUNINIT(esp_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
1018 xform_detach, &esp_xformsw);
Cache object: ec4198c2d82b6354bc7e956ac1b88444
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