1/* $NetBSD: xform_esp.c,v 1.46 2015/03/30 03:51:50 ozaki-r Exp $ */
2/* $FreeBSD: src/sys/netipsec/xform_esp.c,v 1.2.2.1 2003/01/24 05:11:36 sam Exp $ */
3/* $OpenBSD: ip_esp.c,v 1.69 2001/06/26 06:18:59 angelos Exp $ */
4
5/*
6 * The authors of this code are John Ioannidis (ji@tla.org),
7 * Angelos D. Keromytis (kermit@csd.uch.gr) and
8 * Niels Provos (provos@physnet.uni-hamburg.de).
9 *
10 * The original version of this code was written by John Ioannidis
11 * for BSD/OS in Athens, Greece, in November 1995.
12 *
13 * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
14 * by Angelos D. Keromytis.
15 *
16 * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
17 * and Niels Provos.
18 *
19 * Additional features in 1999 by Angelos D. Keromytis.
20 *
21 * Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
22 * Angelos D. Keromytis and Niels Provos.
23 * Copyright (c) 2001 Angelos D. Keromytis.
24 *
25 * Permission to use, copy, and modify this software with or without fee
26 * is hereby granted, provided that this entire notice is included in
27 * all copies of any software which is or includes a copy or
28 * modification of this software.
29 * You may use this code under the GNU public license if you so wish. Please
30 * contribute changes back to the authors under this freer than GPL license
31 * so that we may further the use of strong encryption without limitations to
32 * all.
33 *
34 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
35 * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
36 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
37 * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
38 * PURPOSE.
39 */
40
41#include <sys/cdefs.h>
42__KERNEL_RCSID(0, "$NetBSD: xform_esp.c,v 1.46 2015/03/30 03:51:50 ozaki-r Exp $");
43
44#include "opt_inet.h"
45#ifdef __FreeBSD__
46#include "opt_inet6.h"
47#endif
48#include "opt_ipsec.h"
49
50#include <sys/param.h>
51#include <sys/systm.h>
52#include <sys/mbuf.h>
53#include <sys/socket.h>
54#include <sys/syslog.h>
55#include <sys/kernel.h>
56/*#include <sys/random.h>*/
57#include <sys/sysctl.h>
58#include <sys/socketvar.h> /* for softnet_lock */
59
60#include <net/if.h>
61
62#include <netinet/in.h>
63#include <netinet/in_systm.h>
64#include <netinet/ip.h>
65#include <netinet/ip_ecn.h>
66#include <netinet/ip6.h>
67
68#include <net/route.h>
69#include <netipsec/ipsec.h>
70#include <netipsec/ipsec_private.h>
71#include <netipsec/ah.h>
72#include <netipsec/ah_var.h>
73#include <netipsec/esp.h>
74#include <netipsec/esp_var.h>
75#include <netipsec/xform.h>
76
77#ifdef INET6
78#include <netinet6/ip6_var.h>
79#include <netipsec/ipsec6.h>
80# ifdef __FreeBSD__
81# include <netinet6/ip6_ecn.h>
82# endif
83#endif
84
85#include <netipsec/key.h>
86#include <netipsec/key_debug.h>
87
88#include <netipsec/ipsec_osdep.h>
89
90#include <opencrypto/cryptodev.h>
91#include <opencrypto/xform.h>
92
93percpu_t *espstat_percpu;
94
95int esp_enable = 1;
96
97#ifdef __FreeBSD__
98SYSCTL_DECL(_net_inet_esp);
99SYSCTL_INT(_net_inet_esp, OID_AUTO,
100 esp_enable, CTLFLAG_RW, &esp_enable, 0, "");
101SYSCTL_STRUCT(_net_inet_esp, IPSECCTL_STATS,
102 stats, CTLFLAG_RD, &espstat, espstat, "");
103#endif /* __FreeBSD__ */
104
105static int esp_max_ivlen; /* max iv length over all algorithms */
106
107static int esp_input_cb(struct cryptop *op);
108static int esp_output_cb(struct cryptop *crp);
109
110/*
111 * NB: this is public for use by the PF_KEY support.
112 * NB: if you add support here; be sure to add code to esp_attach below!
113 */
114const struct enc_xform *
115esp_algorithm_lookup(int alg)
116{
117 if (alg >= ESP_ALG_MAX)
118 return NULL;
119 switch (alg) {
120 case SADB_EALG_DESCBC:
121 return &enc_xform_des;
122 case SADB_EALG_3DESCBC:
123 return &enc_xform_3des;
124 case SADB_X_EALG_AES:
125 return &enc_xform_rijndael128;
126 case SADB_X_EALG_BLOWFISHCBC:
127 return &enc_xform_blf;
128 case SADB_X_EALG_CAST128CBC:
129 return &enc_xform_cast5;
130 case SADB_X_EALG_SKIPJACK:
131 return &enc_xform_skipjack;
132 case SADB_X_EALG_CAMELLIACBC:
133 return &enc_xform_camellia;
134 case SADB_X_EALG_AESCTR:
135 return &enc_xform_aes_ctr;
136 case SADB_X_EALG_AESGCM16:
137 return &enc_xform_aes_gcm;
138 case SADB_X_EALG_AESGMAC:
139 return &enc_xform_aes_gmac;
140 case SADB_EALG_NULL:
141 return &enc_xform_null;
142 }
143 return NULL;
144}
145
146size_t
147esp_hdrsiz(const struct secasvar *sav)
148{
149 size_t size;
150
151 if (sav != NULL) {
152 /*XXX not right for null algorithm--does it matter??*/
153 IPSEC_ASSERT(sav->tdb_encalgxform != NULL,
154 ("esp_hdrsiz: SA with null xform"));
155 if (sav->flags & SADB_X_EXT_OLD)
156 size = sizeof (struct esp);
157 else
158 size = sizeof (struct newesp);
159 size += sav->tdb_encalgxform->ivsize + 9;
160 /*XXX need alg check???*/
161 if (sav->tdb_authalgxform != NULL && sav->replay)
162 size += ah_hdrsiz(sav);
163 } else {
164 /*
165 * base header size
166 * + max iv length for CBC mode
167 * + max pad length
168 * + sizeof (pad length field)
169 * + sizeof (next header field)
170 * + max icv supported.
171 */
172 size = sizeof (struct newesp) + esp_max_ivlen + 9 + 16;
173 }
174 return size;
175}
176
177/*
178 * esp_init() is called when an SPI is being set up.
179 */
180static int
181esp_init(struct secasvar *sav, const struct xformsw *xsp)
182{
183 const struct enc_xform *txform;
184 struct cryptoini cria, crie;
185 int keylen;
186 int error;
187
188 txform = esp_algorithm_lookup(sav->alg_enc);
189 if (txform == NULL) {
190 DPRINTF(("esp_init: unsupported encryption algorithm %d\n",
191 sav->alg_enc));
192 return EINVAL;
193 }
194 if (sav->key_enc == NULL) {
195 DPRINTF(("esp_init: no encoding key for %s algorithm\n",
196 txform->name));
197 return EINVAL;
198 }
199 if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) {
200 DPRINTF(("esp_init: 4-byte IV not supported with protocol\n"));
201 return EINVAL;
202 }
203 keylen = _KEYLEN(sav->key_enc);
204 if (txform->minkey > keylen || keylen > txform->maxkey) {
205 DPRINTF(("esp_init: invalid key length %u, must be in "
206 "the range [%u..%u] for algorithm %s\n",
207 keylen, txform->minkey, txform->maxkey,
208 txform->name));
209 return EINVAL;
210 }
211
212 sav->ivlen = txform->ivsize;
213
214 /*
215 * Setup AH-related state.
216 */
217 if (sav->alg_auth != 0) {
218 error = ah_init0(sav, xsp, &cria);
219 if (error)
220 return error;
221 }
222
223 /* NB: override anything set in ah_init0 */
224 sav->tdb_xform = xsp;
225 sav->tdb_encalgxform = txform;
226
227 if (sav->alg_enc == SADB_X_EALG_AESGCM16 ||
228 sav->alg_enc == SADB_X_EALG_AESGMAC) {
229 switch (keylen) {
230 case 20:
231 sav->alg_auth = SADB_X_AALG_AES128GMAC;
232 sav->tdb_authalgxform = &auth_hash_gmac_aes_128;
233 break;
234 case 28:
235 sav->alg_auth = SADB_X_AALG_AES192GMAC;
236 sav->tdb_authalgxform = &auth_hash_gmac_aes_192;
237 break;
238 case 36:
239 sav->alg_auth = SADB_X_AALG_AES256GMAC;
240 sav->tdb_authalgxform = &auth_hash_gmac_aes_256;
241 break;
242 }
243 memset(&cria, 0, sizeof(cria));
244 cria.cri_alg = sav->tdb_authalgxform->type;
245 cria.cri_klen = _KEYBITS(sav->key_enc);
246 cria.cri_key = _KEYBUF(sav->key_enc);
247 }
248
249 /* Initialize crypto session. */
250 memset(&crie, 0, sizeof (crie));
251 crie.cri_alg = sav->tdb_encalgxform->type;
252 crie.cri_klen = _KEYBITS(sav->key_enc);
253 crie.cri_key = _KEYBUF(sav->key_enc);
254 /* XXX Rounds ? */
255
256 if (sav->tdb_authalgxform && sav->tdb_encalgxform) {
257 /* init both auth & enc */
258 crie.cri_next = &cria;
259 error = crypto_newsession(&sav->tdb_cryptoid,
260 &crie, crypto_support);
261 } else if (sav->tdb_encalgxform) {
262 error = crypto_newsession(&sav->tdb_cryptoid,
263 &crie, crypto_support);
264 } else if (sav->tdb_authalgxform) {
265 error = crypto_newsession(&sav->tdb_cryptoid,
266 &cria, crypto_support);
267 } else {
268 /* XXX cannot happen? */
269 DPRINTF(("esp_init: no encoding OR authentication xform!\n"));
270 error = EINVAL;
271 }
272 return error;
273}
274
275/*
276 * Paranoia.
277 */
278static int
279esp_zeroize(struct secasvar *sav)
280{
281 /* NB: ah_zerorize free's the crypto session state */
282 int error = ah_zeroize(sav);
283
284 if (sav->key_enc)
285 memset(_KEYBUF(sav->key_enc), 0, _KEYLEN(sav->key_enc));
286 sav->tdb_encalgxform = NULL;
287 sav->tdb_xform = NULL;
288 return error;
289}
290
291/*
292 * ESP input processing, called (eventually) through the protocol switch.
293 */
294static int
295esp_input(struct mbuf *m, const struct secasvar *sav, int skip, int protoff)
296{
297 const struct auth_hash *esph;
298 const struct enc_xform *espx;
299 struct tdb_ident *tdbi;
300 struct tdb_crypto *tc;
301 int plen, alen, hlen, error;
302 struct m_tag *mtag;
303 struct newesp *esp;
304
305 struct cryptodesc *crde;
306 struct cryptop *crp;
307
308 IPSEC_SPLASSERT_SOFTNET("esp_input");
309
310 IPSEC_ASSERT(sav != NULL, ("esp_input: null SA"));
311 IPSEC_ASSERT(sav->tdb_encalgxform != NULL,
312 ("esp_input: null encoding xform"));
313 IPSEC_ASSERT((skip&3) == 0 && (m->m_pkthdr.len&3) == 0,
314 ("esp_input: misaligned packet, skip %u pkt len %u",
315 skip, m->m_pkthdr.len));
316
317 /* XXX don't pullup, just copy header */
318 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp));
319
320 esph = sav->tdb_authalgxform;
321 espx = sav->tdb_encalgxform;
322
323 /* Determine the ESP header length */
324 if (sav->flags & SADB_X_EXT_OLD)
325 hlen = sizeof (struct esp) + sav->ivlen;
326 else
327 hlen = sizeof (struct newesp) + sav->ivlen;
328 /* Authenticator hash size */
329 alen = esph ? esph->authsize : 0;
330
331 /*
332 * Verify payload length is multiple of encryption algorithm
333 * block size.
334 *
335 * NB: This works for the null algorithm because the blocksize
336 * is 4 and all packets must be 4-byte aligned regardless
337 * of the algorithm.
338 */
339 plen = m->m_pkthdr.len - (skip + hlen + alen);
340 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) {
341 DPRINTF(("esp_input: "
342 "payload of %d octets not a multiple of %d octets,"
343 " SA %s/%08lx\n",
344 plen, espx->blocksize,
345 ipsec_address(&sav->sah->saidx.dst),
346 (u_long) ntohl(sav->spi)));
347 ESP_STATINC(ESP_STAT_BADILEN);
348 m_freem(m);
349 return EINVAL;
350 }
351
352 /*
353 * Check sequence number.
354 */
355 if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) {
356 DPRINTF(("esp_input: packet replay check for %s\n",
357 ipsec_logsastr(sav))); /*XXX*/
358 ESP_STATINC(ESP_STAT_REPLAY);
359 m_freem(m);
360 return ENOBUFS; /*XXX*/
361 }
362
363 /* Update the counters */
364 ESP_STATADD(ESP_STAT_IBYTES, m->m_pkthdr.len - skip - hlen - alen);
365
366 /* Find out if we've already done crypto */
367 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL);
368 mtag != NULL;
369 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) {
370 tdbi = (struct tdb_ident *) (mtag + 1);
371 if (tdbi->proto == sav->sah->saidx.proto &&
372 tdbi->spi == sav->spi &&
373 !memcmp(&tdbi->dst, &sav->sah->saidx.dst,
374 sizeof(union sockaddr_union)))
375 break;
376 }
377
378 /* Get crypto descriptors */
379 crp = crypto_getreq(esph && espx ? 2 : 1);
380 if (crp == NULL) {
381 DPRINTF(("esp_input: failed to acquire crypto descriptors\n"));
382 ESP_STATINC(ESP_STAT_CRYPTO);
383 m_freem(m);
384 return ENOBUFS;
385 }
386
387 /* Get IPsec-specific opaque pointer */
388 if (esph == NULL || mtag != NULL)
389 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
390 M_XDATA, M_NOWAIT|M_ZERO);
391 else
392 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen,
393 M_XDATA, M_NOWAIT|M_ZERO);
394 if (tc == NULL) {
395 crypto_freereq(crp);
396 DPRINTF(("esp_input: failed to allocate tdb_crypto\n"));
397 ESP_STATINC(ESP_STAT_CRYPTO);
398 m_freem(m);
399 return ENOBUFS;
400 }
401
402 error = m_makewritable(&m, 0, m->m_pkthdr.len, M_NOWAIT);
403 if (error) {
404 m_freem(m);
405 free(tc, M_XDATA);
406 crypto_freereq(crp);
407 DPRINTF(("esp_input: m_makewritable failed\n"));
408 ESP_STATINC(ESP_STAT_CRYPTO);
409 return error;
410 }
411
412 tc->tc_ptr = mtag;
413
414 if (esph) {
415 struct cryptodesc *crda = crp->crp_desc;
416
417 IPSEC_ASSERT(crda != NULL, ("esp_input: null ah crypto descriptor"));
418
419 /* Authentication descriptor */
420 crda->crd_skip = skip;
421 if (espx && espx->type == CRYPTO_AES_GCM_16)
422 crda->crd_len = hlen - sav->ivlen;
423 else
424 crda->crd_len = m->m_pkthdr.len - (skip + alen);
425 crda->crd_inject = m->m_pkthdr.len - alen;
426
427 crda->crd_alg = esph->type;
428 if (espx && (espx->type == CRYPTO_AES_GCM_16 ||
429 espx->type == CRYPTO_AES_GMAC)) {
430 crda->crd_key = _KEYBUF(sav->key_enc);
431 crda->crd_klen = _KEYBITS(sav->key_enc);
432 } else {
433 crda->crd_key = _KEYBUF(sav->key_auth);
434 crda->crd_klen = _KEYBITS(sav->key_auth);
435 }
436
437 /* Copy the authenticator */
438 if (mtag == NULL)
439 m_copydata(m, m->m_pkthdr.len - alen, alen,
440 (tc + 1));
441
442 /* Chain authentication request */
443 crde = crda->crd_next;
444 } else {
445 crde = crp->crp_desc;
446 }
447
448 /* Crypto operation descriptor */
449 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */
450 crp->crp_flags = CRYPTO_F_IMBUF;
451 crp->crp_buf = m;
452 crp->crp_callback = esp_input_cb;
453 crp->crp_sid = sav->tdb_cryptoid;
454 crp->crp_opaque = tc;
455
456 /* These are passed as-is to the callback */
457 tc->tc_spi = sav->spi;
458 tc->tc_dst = sav->sah->saidx.dst;
459 tc->tc_proto = sav->sah->saidx.proto;
460 tc->tc_protoff = protoff;
461 tc->tc_skip = skip;
462
463 /* Decryption descriptor */
464 if (espx) {
465 IPSEC_ASSERT(crde != NULL, ("esp_input: null esp crypto descriptor"));
466 crde->crd_skip = skip + hlen;
467 if (espx->type == CRYPTO_AES_GMAC)
468 crde->crd_len = 0;
469 else
470 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
471 crde->crd_inject = skip + hlen - sav->ivlen;
472
473 crde->crd_alg = espx->type;
474 crde->crd_key = _KEYBUF(sav->key_enc);
475 crde->crd_klen = _KEYBITS(sav->key_enc);
476 /* XXX Rounds ? */
477 }
478
479 if (mtag == NULL)
480 return crypto_dispatch(crp);
481 else
482 return esp_input_cb(crp);
483}
484
485#ifdef INET6
486#define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \
487 if (saidx->dst.sa.sa_family == AF_INET6) { \
488 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \
489 } else { \
490 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \
491 } \
492} while (0)
493#else
494#define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \
495 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag))
496#endif
497
498/*
499 * ESP input callback from the crypto driver.
500 */
501static int
502esp_input_cb(struct cryptop *crp)
503{
504 u_int8_t lastthree[3], aalg[AH_ALEN_MAX];
505 int s, hlen, skip, protoff, error;
506 struct mbuf *m;
507 struct cryptodesc *crd __diagused;
508 const struct auth_hash *esph;
509 struct tdb_crypto *tc;
510 struct m_tag *mtag;
511 struct secasvar *sav;
512 struct secasindex *saidx;
513 void *ptr;
514 u_int16_t dport;
515 u_int16_t sport;
516
517 crd = crp->crp_desc;
518 IPSEC_ASSERT(crd != NULL, ("esp_input_cb: null crypto descriptor!"));
519
520 tc = (struct tdb_crypto *) crp->crp_opaque;
521 IPSEC_ASSERT(tc != NULL, ("esp_input_cb: null opaque crypto data area!"));
522 skip = tc->tc_skip;
523 protoff = tc->tc_protoff;
524 mtag = (struct m_tag *) tc->tc_ptr;
525 m = (struct mbuf *) crp->crp_buf;
526
527 /* find the source port for NAT-T */
528 nat_t_ports_get(m, &dport, &sport);
529
530 s = splsoftnet();
531 mutex_enter(softnet_lock);
532
533 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi, sport, dport);
534 if (sav == NULL) {
535 ESP_STATINC(ESP_STAT_NOTDB);
536 DPRINTF(("esp_input_cb: SA expired while in crypto "
537 "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst),
538 (u_long) ntohl(tc->tc_spi), tc->tc_proto));
539 error = ENOBUFS; /*XXX*/
540 goto bad;
541 }
542
543 saidx = &sav->sah->saidx;
544 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
545 saidx->dst.sa.sa_family == AF_INET6,
546 ("esp_input_cb: unexpected protocol family %u",
547 saidx->dst.sa.sa_family));
548
549 esph = sav->tdb_authalgxform;
550
551 /* Check for crypto errors */
552 if (crp->crp_etype) {
553 /* Reset the session ID */
554 if (sav->tdb_cryptoid != 0)
555 sav->tdb_cryptoid = crp->crp_sid;
556
557 if (crp->crp_etype == EAGAIN) {
558 KEY_FREESAV(&sav);
559 mutex_exit(softnet_lock);
560 splx(s);
561 return crypto_dispatch(crp);
562 }
563
564 ESP_STATINC(ESP_STAT_NOXFORM);
565 DPRINTF(("esp_input_cb: crypto error %d\n", crp->crp_etype));
566 error = crp->crp_etype;
567 goto bad;
568 }
569
570 /* Shouldn't happen... */
571 if (m == NULL) {
572 ESP_STATINC(ESP_STAT_CRYPTO);
573 DPRINTF(("esp_input_cb: bogus returned buffer from crypto\n"));
574 error = EINVAL;
575 goto bad;
576 }
577 ESP_STATINC(ESP_STAT_HIST + sav->alg_enc);
578
579 /* If authentication was performed, check now. */
580 if (esph != NULL) {
581 /*
582 * If we have a tag, it means an IPsec-aware NIC did
583 * the verification for us. Otherwise we need to
584 * check the authentication calculation.
585 */
586 AH_STATINC(AH_STAT_HIST + sav->alg_auth);
587 if (mtag == NULL) {
588 /* Copy the authenticator from the packet */
589 m_copydata(m, m->m_pkthdr.len - esph->authsize,
590 esph->authsize, aalg);
591
592 ptr = (tc + 1);
593
594 /* Verify authenticator */
595 if (!consttime_memequal(ptr, aalg, esph->authsize)) {
596 DPRINTF(("esp_input_cb: "
597 "authentication hash mismatch for packet in SA %s/%08lx\n",
598 ipsec_address(&saidx->dst),
599 (u_long) ntohl(sav->spi)));
600 ESP_STATINC(ESP_STAT_BADAUTH);
601 error = EACCES;
602 goto bad;
603 }
604 }
605
606 /* Remove trailing authenticator */
607 m_adj(m, -(esph->authsize));
608 }
609
610 /* Release the crypto descriptors */
611 free(tc, M_XDATA), tc = NULL;
612 crypto_freereq(crp), crp = NULL;
613
614 /*
615 * Packet is now decrypted.
616 */
617 m->m_flags |= M_DECRYPTED;
618
619 /*
620 * Update replay sequence number, if appropriate.
621 */
622 if (sav->replay) {
623 u_int32_t seq;
624
625 m_copydata(m, skip + offsetof(struct newesp, esp_seq),
626 sizeof (seq), &seq);
627 if (ipsec_updatereplay(ntohl(seq), sav)) {
628 DPRINTF(("%s: packet replay check for %s\n", __func__,
629 ipsec_logsastr(sav)));
630 ESP_STATINC(ESP_STAT_REPLAY);
631 error = ENOBUFS;
632 goto bad;
633 }
634 }
635
636 /* Determine the ESP header length */
637 if (sav->flags & SADB_X_EXT_OLD)
638 hlen = sizeof (struct esp) + sav->ivlen;
639 else
640 hlen = sizeof (struct newesp) + sav->ivlen;
641
642 /* Remove the ESP header and IV from the mbuf. */
643 error = m_striphdr(m, skip, hlen);
644 if (error) {
645 ESP_STATINC(ESP_STAT_HDROPS);
646 DPRINTF(("esp_input_cb: bad mbuf chain, SA %s/%08lx\n",
647 ipsec_address(&sav->sah->saidx.dst),
648 (u_long) ntohl(sav->spi)));
649 goto bad;
650 }
651
652 /* Save the last three bytes of decrypted data */
653 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree);
654
655 /* Verify pad length */
656 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) {
657 ESP_STATINC(ESP_STAT_BADILEN);
658 DPRINTF(("esp_input_cb: invalid padding length %d "
659 "for %u byte packet in SA %s/%08lx\n",
660 lastthree[1], m->m_pkthdr.len - skip,
661 ipsec_address(&sav->sah->saidx.dst),
662 (u_long) ntohl(sav->spi)));
663 error = EINVAL;
664 goto bad;
665 }
666
667 /* Verify correct decryption by checking the last padding bytes */
668 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) {
669 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) {
670 ESP_STATINC(ESP_STAT_BADENC);
671 DPRINTF(("esp_input_cb: decryption failed "
672 "for packet in SA %s/%08lx\n",
673 ipsec_address(&sav->sah->saidx.dst),
674 (u_long) ntohl(sav->spi)));
675DPRINTF(("esp_input_cb: %x %x\n", lastthree[0], lastthree[1]));
676 error = EINVAL;
677 goto bad;
678 }
679 }
680
681 /* Trim the mbuf chain to remove trailing authenticator and padding */
682 m_adj(m, -(lastthree[1] + 2));
683
684 /* Restore the Next Protocol field */
685 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2);
686
687 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag);
688
689 KEY_FREESAV(&sav);
690 mutex_exit(softnet_lock);
691 splx(s);
692 return error;
693bad:
694 if (sav)
695 KEY_FREESAV(&sav);
696 mutex_exit(softnet_lock);
697 splx(s);
698 if (m != NULL)
699 m_freem(m);
700 if (tc != NULL)
701 free(tc, M_XDATA);
702 if (crp != NULL)
703 crypto_freereq(crp);
704 return error;
705}
706
707/*
708 * ESP output routine, called by ipsec[46]_process_packet().
709 */
710static int
711esp_output(
712 struct mbuf *m,
713 struct ipsecrequest *isr,
714 struct mbuf **mp,
715 int skip,
716 int protoff
717)
718{
719 const struct enc_xform *espx;
720 const struct auth_hash *esph;
721 int hlen, rlen, padding, blks, alen, i, roff;
722 struct mbuf *mo = NULL;
723 struct tdb_crypto *tc;
724 const struct secasvar *sav;
725 struct secasindex *saidx;
726 unsigned char *pad;
727 u_int8_t prot;
728 int error, maxpacketsize;
729
730 struct cryptodesc *crde = NULL, *crda = NULL;
731 struct cryptop *crp;
732
733 IPSEC_SPLASSERT_SOFTNET("esp_output");
734
735 sav = isr->sav;
736 IPSEC_ASSERT(sav != NULL, ("esp_output: null SA"));
737 esph = sav->tdb_authalgxform;
738 espx = sav->tdb_encalgxform;
739 IPSEC_ASSERT(espx != NULL, ("esp_output: null encoding xform"));
740
741 if (sav->flags & SADB_X_EXT_OLD)
742 hlen = sizeof (struct esp) + sav->ivlen;
743 else
744 hlen = sizeof (struct newesp) + sav->ivlen;
745
746 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */
747 /*
748 * NB: The null encoding transform has a blocksize of 4
749 * so that headers are properly aligned.
750 */
751 blks = espx->blocksize; /* IV blocksize */
752
753 /* XXX clamp padding length a la KAME??? */
754 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;
755
756 if (esph)
757 alen = esph->authsize;
758 else
759 alen = 0;
760
761 ESP_STATINC(ESP_STAT_OUTPUT);
762
763 saidx = &sav->sah->saidx;
764 /* Check for maximum packet size violations. */
765 switch (saidx->dst.sa.sa_family) {
766#ifdef INET
767 case AF_INET:
768 maxpacketsize = IP_MAXPACKET;
769 break;
770#endif /* INET */
771#ifdef INET6
772 case AF_INET6:
773 maxpacketsize = IPV6_MAXPACKET;
774 break;
775#endif /* INET6 */
776 default:
777 DPRINTF(("esp_output: unknown/unsupported protocol "
778 "family %d, SA %s/%08lx\n",
779 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst),
780 (u_long) ntohl(sav->spi)));
781 ESP_STATINC(ESP_STAT_NOPF);
782 error = EPFNOSUPPORT;
783 goto bad;
784 }
785 if (skip + hlen + rlen + padding + alen > maxpacketsize) {
786 DPRINTF(("esp_output: packet in SA %s/%08lx got too big "
787 "(len %u, max len %u)\n",
788 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi),
789 skip + hlen + rlen + padding + alen, maxpacketsize));
790 ESP_STATINC(ESP_STAT_TOOBIG);
791 error = EMSGSIZE;
792 goto bad;
793 }
794
795 /* Update the counters. */
796 ESP_STATADD(ESP_STAT_OBYTES, m->m_pkthdr.len - skip);
797
798 m = m_clone(m);
799 if (m == NULL) {
800 DPRINTF(("esp_output: cannot clone mbuf chain, SA %s/%08lx\n",
801 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
802 ESP_STATINC(ESP_STAT_HDROPS);
803 error = ENOBUFS;
804 goto bad;
805 }
806
807 /* Inject ESP header. */
808 mo = m_makespace(m, skip, hlen, &roff);
809 if (mo == NULL) {
810 DPRINTF(("esp_output: failed to inject %u byte ESP hdr for SA "
811 "%s/%08lx\n",
812 hlen, ipsec_address(&saidx->dst),
813 (u_long) ntohl(sav->spi)));
814 ESP_STATINC(ESP_STAT_HDROPS); /* XXX diffs from openbsd */
815 error = ENOBUFS;
816 goto bad;
817 }
818
819 /* Initialize ESP header. */
820 memcpy(mtod(mo, char *) + roff, &sav->spi, sizeof(u_int32_t));
821 if (sav->replay) {
822 u_int32_t replay;
823
824#ifdef IPSEC_DEBUG
825 /* Emulate replay attack when ipsec_replay is TRUE. */
826 if (!ipsec_replay)
827#endif
828 sav->replay->count++;
829
830 replay = htonl(sav->replay->count);
831 bcopy(&replay,
832 mtod(mo,char *) + roff + sizeof(u_int32_t),
833 sizeof(u_int32_t));
834 }
835
836 /*
837 * Add padding -- better to do it ourselves than use the crypto engine,
838 * although if/when we support compression, we'd have to do that.
839 */
840 pad = (u_char *) m_pad(m, padding + alen);
841 if (pad == NULL) {
842 DPRINTF(("esp_output: m_pad failed for SA %s/%08lx\n",
843 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
844 m = NULL; /* NB: free'd by m_pad */
845 error = ENOBUFS;
846 goto bad;
847 }
848
849 /*
850 * Add padding: random, zero, or self-describing.
851 * XXX catch unexpected setting
852 */
853 switch (sav->flags & SADB_X_EXT_PMASK) {
854 case SADB_X_EXT_PRAND:
855 (void) read_random(pad, padding - 2);
856 break;
857 case SADB_X_EXT_PZERO:
858 memset(pad, 0, padding - 2);
859 break;
860 case SADB_X_EXT_PSEQ:
861 for (i = 0; i < padding - 2; i++)
862 pad[i] = i+1;
863 break;
864 }
865
866 /* Fix padding length and Next Protocol in padding itself. */
867 pad[padding - 2] = padding - 2;
868 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1);
869
870 /* Fix Next Protocol in IPv4/IPv6 header. */
871 prot = IPPROTO_ESP;
872 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot);
873
874 /* Get crypto descriptors. */
875 crp = crypto_getreq(esph && espx ? 2 : 1);
876 if (crp == NULL) {
877 DPRINTF(("esp_output: failed to acquire crypto descriptors\n"));
878 ESP_STATINC(ESP_STAT_CRYPTO);
879 error = ENOBUFS;
880 goto bad;
881 }
882
883 if (espx) {
884 crde = crp->crp_desc;
885 crda = crde->crd_next;
886
887 /* Encryption descriptor. */
888 crde->crd_skip = skip + hlen;
889 if (espx->type == CRYPTO_AES_GMAC)
890 crde->crd_len = 0;
891 else
892 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
893 crde->crd_flags = CRD_F_ENCRYPT;
894 crde->crd_inject = skip + hlen - sav->ivlen;
895
896 /* Encryption operation. */
897 crde->crd_alg = espx->type;
898 crde->crd_key = _KEYBUF(sav->key_enc);
899 crde->crd_klen = _KEYBITS(sav->key_enc);
900 /* XXX Rounds ? */
901 } else
902 crda = crp->crp_desc;
903
904 /* IPsec-specific opaque crypto info. */
905 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
906 M_XDATA, M_NOWAIT|M_ZERO);
907 if (tc == NULL) {
908 crypto_freereq(crp);
909 DPRINTF(("esp_output: failed to allocate tdb_crypto\n"));
910 ESP_STATINC(ESP_STAT_CRYPTO);
911 error = ENOBUFS;
912 goto bad;
913 }
914
915 /* Callback parameters */
916 tc->tc_isr = isr;
917 tc->tc_spi = sav->spi;
918 tc->tc_dst = saidx->dst;
919 tc->tc_proto = saidx->proto;
920
921 /* Crypto operation descriptor. */
922 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
923 crp->crp_flags = CRYPTO_F_IMBUF;
924 crp->crp_buf = m;
925 crp->crp_callback = esp_output_cb;
926 crp->crp_opaque = tc;
927 crp->crp_sid = sav->tdb_cryptoid;
928
929 if (esph) {
930 /* Authentication descriptor. */
931 crda->crd_skip = skip;
932 if (espx && espx->type == CRYPTO_AES_GCM_16)
933 crda->crd_len = hlen - sav->ivlen;
934 else
935 crda->crd_len = m->m_pkthdr.len - (skip + alen);
936 crda->crd_inject = m->m_pkthdr.len - alen;
937
938 /* Authentication operation. */
939 crda->crd_alg = esph->type;
940 if (espx && (espx->type == CRYPTO_AES_GCM_16 ||
941 espx->type == CRYPTO_AES_GMAC)) {
942 crda->crd_key = _KEYBUF(sav->key_enc);
943 crda->crd_klen = _KEYBITS(sav->key_enc);
944 } else {
945 crda->crd_key = _KEYBUF(sav->key_auth);
946 crda->crd_klen = _KEYBITS(sav->key_auth);
947 }
948 }
949
950 return crypto_dispatch(crp);
951bad:
952 if (m)
953 m_freem(m);
954 return (error);
955}
956
957/*
958 * ESP output callback from the crypto driver.
959 */
960static int
961esp_output_cb(struct cryptop *crp)
962{
963 struct tdb_crypto *tc;
964 struct ipsecrequest *isr;
965 struct secasvar *sav;
966 struct mbuf *m;
967 int s, err, error;
968
969 tc = (struct tdb_crypto *) crp->crp_opaque;
970 IPSEC_ASSERT(tc != NULL, ("esp_output_cb: null opaque data area!"));
971 m = (struct mbuf *) crp->crp_buf;
972
973 s = splsoftnet();
974 mutex_enter(softnet_lock);
975
976 isr = tc->tc_isr;
977 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi, 0, 0);
978 if (sav == NULL) {
979 ESP_STATINC(ESP_STAT_NOTDB);
980 DPRINTF(("esp_output_cb: SA expired while in crypto "
981 "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst),
982 (u_long) ntohl(tc->tc_spi), tc->tc_proto));
983 error = ENOBUFS; /*XXX*/
984 goto bad;
985 }
986 IPSEC_ASSERT(isr->sav == sav,
987 ("esp_output_cb: SA changed was %p now %p\n", isr->sav, sav));
988
989 /* Check for crypto errors. */
990 if (crp->crp_etype) {
991 /* Reset session ID. */
992 if (sav->tdb_cryptoid != 0)
993 sav->tdb_cryptoid = crp->crp_sid;
994
995 if (crp->crp_etype == EAGAIN) {
996 KEY_FREESAV(&sav);
997 mutex_exit(softnet_lock);
998 splx(s);
999 return crypto_dispatch(crp);
1000 }
1001
1002 ESP_STATINC(ESP_STAT_NOXFORM);
1003 DPRINTF(("esp_output_cb: crypto error %d\n", crp->crp_etype));
1004 error = crp->crp_etype;
1005 goto bad;
1006 }
1007
1008 /* Shouldn't happen... */
1009 if (m == NULL) {
1010 ESP_STATINC(ESP_STAT_CRYPTO);
1011 DPRINTF(("esp_output_cb: bogus returned buffer from crypto\n"));
1012 error = EINVAL;
1013 goto bad;
1014 }
1015 ESP_STATINC(ESP_STAT_HIST + sav->alg_enc);
1016 if (sav->tdb_authalgxform != NULL)
1017 AH_STATINC(AH_STAT_HIST + sav->alg_auth);
1018
1019 /* Release crypto descriptors. */
1020 free(tc, M_XDATA);
1021 crypto_freereq(crp);
1022
1023#ifdef IPSEC_DEBUG
1024 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
1025 if (ipsec_integrity) {
1026 static unsigned char ipseczeroes[AH_ALEN_MAX];
1027 const struct auth_hash *esph;
1028
1029 /*
1030 * Corrupt HMAC if we want to test integrity verification of
1031 * the other side.
1032 */
1033 esph = sav->tdb_authalgxform;
1034 if (esph != NULL) {
1035 m_copyback(m, m->m_pkthdr.len - esph->authsize,
1036 esph->authsize, ipseczeroes);
1037 }
1038 }
1039#endif
1040
1041 /* NB: m is reclaimed by ipsec_process_done. */
1042 err = ipsec_process_done(m, isr);
1043 KEY_FREESAV(&sav);
1044 mutex_exit(softnet_lock);
1045 splx(s);
1046 return err;
1047bad:
1048 if (sav)
1049 KEY_FREESAV(&sav);
1050 mutex_exit(softnet_lock);
1051 splx(s);
1052 if (m)
1053 m_freem(m);
1054 free(tc, M_XDATA);
1055 crypto_freereq(crp);
1056 return error;
1057}
1058
1059static struct xformsw esp_xformsw = {
1060 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP",
1061 esp_init, esp_zeroize, esp_input,
1062 esp_output,
1063 NULL,
1064};
1065
1066INITFN void
1067esp_attach(void)
1068{
1069
1070 espstat_percpu = percpu_alloc(sizeof(uint64_t) * ESP_NSTATS);
1071
1072#define MAXIV(xform) \
1073 if (xform.ivsize > esp_max_ivlen) \
1074 esp_max_ivlen = xform.ivsize \
1075
1076 esp_max_ivlen = 0;
1077 MAXIV(enc_xform_des); /* SADB_EALG_DESCBC */
1078 MAXIV(enc_xform_3des); /* SADB_EALG_3DESCBC */
1079 MAXIV(enc_xform_rijndael128); /* SADB_X_EALG_AES */
1080 MAXIV(enc_xform_blf); /* SADB_X_EALG_BLOWFISHCBC */
1081 MAXIV(enc_xform_cast5); /* SADB_X_EALG_CAST128CBC */
1082 MAXIV(enc_xform_skipjack); /* SADB_X_EALG_SKIPJACK */
1083 MAXIV(enc_xform_camellia); /* SADB_X_EALG_CAMELLIACBC */
1084 MAXIV(enc_xform_aes_ctr); /* SADB_X_EALG_AESCTR */
1085 MAXIV(enc_xform_null); /* SADB_EALG_NULL */
1086
1087 xform_register(&esp_xformsw);
1088#undef MAXIV
1089}
1090#ifdef __FreeBSD__
1091SYSINIT(esp_xform_init, SI_SUB_DRIVERS, SI_ORDER_FIRST, esp_attach, NULL)
1092#else
1093#endif
1094