1 /* $FreeBSD: releng/11.0/sys/netipsec/xform_esp.c 290924 2015-11-16 07:10:42Z ae $ */
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
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/mbuf.h>
44 #include <sys/socket.h>
45 #include <sys/syslog.h>
46 #include <sys/kernel.h>
47 #include <sys/lock.h>
48 #include <sys/random.h>
49 #include <sys/rwlock.h>
50 #include <sys/sysctl.h>
51 #include <sys/mutex.h>
52 #include <machine/atomic.h>
53
54 #include <net/if.h>
55 #include <net/vnet.h>
56
57 #include <netinet/in.h>
58 #include <netinet/in_systm.h>
59 #include <netinet/ip.h>
60 #include <netinet/ip_ecn.h>
61 #include <netinet/ip6.h>
62
63 #include <netipsec/ipsec.h>
64 #include <netipsec/ah.h>
65 #include <netipsec/ah_var.h>
66 #include <netipsec/esp.h>
67 #include <netipsec/esp_var.h>
68 #include <netipsec/xform.h>
69
70 #ifdef INET6
71 #include <netinet6/ip6_var.h>
72 #include <netipsec/ipsec6.h>
73 #include <netinet6/ip6_ecn.h>
74 #endif
75
76 #include <netipsec/key.h>
77 #include <netipsec/key_debug.h>
78
79 #include <opencrypto/cryptodev.h>
80 #include <opencrypto/xform.h>
81
82 VNET_DEFINE(int, esp_enable) = 1;
83 VNET_PCPUSTAT_DEFINE(struct espstat, espstat);
84 VNET_PCPUSTAT_SYSINIT(espstat);
85
86 #ifdef VIMAGE
87 VNET_PCPUSTAT_SYSUNINIT(espstat);
88 #endif /* VIMAGE */
89
90 SYSCTL_DECL(_net_inet_esp);
91 SYSCTL_INT(_net_inet_esp, OID_AUTO, esp_enable,
92 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(esp_enable), 0, "");
93 SYSCTL_VNET_PCPUSTAT(_net_inet_esp, IPSECCTL_STATS, stats,
94 struct espstat, espstat,
95 "ESP statistics (struct espstat, netipsec/esp_var.h");
96
97 static int esp_input_cb(struct cryptop *op);
98 static int esp_output_cb(struct cryptop *crp);
99
100 /*
101 * NB: this is public for use by the PF_KEY support.
102 * NB: if you add support here; be sure to add code to esp_attach below!
103 */
104 struct enc_xform *
105 esp_algorithm_lookup(int alg)
106 {
107 if (alg >= ESP_ALG_MAX)
108 return NULL;
109 switch (alg) {
110 case SADB_EALG_DESCBC:
111 return &enc_xform_des;
112 case SADB_EALG_3DESCBC:
113 return &enc_xform_3des;
114 case SADB_X_EALG_AES:
115 return &enc_xform_rijndael128;
116 case SADB_X_EALG_BLOWFISHCBC:
117 return &enc_xform_blf;
118 case SADB_X_EALG_CAST128CBC:
119 return &enc_xform_cast5;
120 case SADB_EALG_NULL:
121 return &enc_xform_null;
122 case SADB_X_EALG_CAMELLIACBC:
123 return &enc_xform_camellia;
124 case SADB_X_EALG_AESCTR:
125 return &enc_xform_aes_icm;
126 case SADB_X_EALG_AESGCM16:
127 return &enc_xform_aes_nist_gcm;
128 case SADB_X_EALG_AESGMAC:
129 return &enc_xform_aes_nist_gmac;
130 }
131 return NULL;
132 }
133
134 size_t
135 esp_hdrsiz(struct secasvar *sav)
136 {
137 size_t size;
138
139 if (sav != NULL) {
140 /*XXX not right for null algorithm--does it matter??*/
141 IPSEC_ASSERT(sav->tdb_encalgxform != NULL,
142 ("SA with null xform"));
143 if (sav->flags & SADB_X_EXT_OLD)
144 size = sizeof (struct esp);
145 else
146 size = sizeof (struct newesp);
147 size += sav->tdb_encalgxform->blocksize + 9;
148 /*XXX need alg check???*/
149 if (sav->tdb_authalgxform != NULL && sav->replay)
150 size += ah_hdrsiz(sav);
151 } else {
152 /*
153 * base header size
154 * + max iv length for CBC mode
155 * + max pad length
156 * + sizeof (pad length field)
157 * + sizeof (next header field)
158 * + max icv supported.
159 */
160 size = sizeof (struct newesp) + EALG_MAX_BLOCK_LEN + 9 + 16;
161 }
162 return size;
163 }
164
165 /*
166 * esp_init() is called when an SPI is being set up.
167 */
168 static int
169 esp_init(struct secasvar *sav, struct xformsw *xsp)
170 {
171 struct enc_xform *txform;
172 struct cryptoini cria, crie;
173 int keylen;
174 int error;
175
176 txform = esp_algorithm_lookup(sav->alg_enc);
177 if (txform == NULL) {
178 DPRINTF(("%s: unsupported encryption algorithm %d\n",
179 __func__, sav->alg_enc));
180 return EINVAL;
181 }
182 if (sav->key_enc == NULL) {
183 DPRINTF(("%s: no encoding key for %s algorithm\n",
184 __func__, txform->name));
185 return EINVAL;
186 }
187 if ((sav->flags & (SADB_X_EXT_OLD | SADB_X_EXT_IV4B)) ==
188 SADB_X_EXT_IV4B) {
189 DPRINTF(("%s: 4-byte IV not supported with protocol\n",
190 __func__));
191 return EINVAL;
192 }
193 /* subtract off the salt, RFC4106, 8.1 and RFC3686, 5.1 */
194 keylen = _KEYLEN(sav->key_enc) - SAV_ISCTRORGCM(sav) * 4;
195 if (txform->minkey > keylen || keylen > txform->maxkey) {
196 DPRINTF(("%s: invalid key length %u, must be in the range "
197 "[%u..%u] for algorithm %s\n", __func__,
198 keylen, txform->minkey, txform->maxkey,
199 txform->name));
200 return EINVAL;
201 }
202
203 if (SAV_ISCTRORGCM(sav))
204 sav->ivlen = 8; /* RFC4106 3.1 and RFC3686 3.1 */
205 else
206 sav->ivlen = txform->ivsize;
207
208 /*
209 * Setup AH-related state.
210 */
211 if (sav->alg_auth != 0) {
212 error = ah_init0(sav, xsp, &cria);
213 if (error)
214 return error;
215 }
216
217 /* NB: override anything set in ah_init0 */
218 sav->tdb_xform = xsp;
219 sav->tdb_encalgxform = txform;
220
221 /*
222 * Whenever AES-GCM is used for encryption, one
223 * of the AES authentication algorithms is chosen
224 * as well, based on the key size.
225 */
226 if (sav->alg_enc == SADB_X_EALG_AESGCM16) {
227 switch (keylen) {
228 case AES_128_GMAC_KEY_LEN:
229 sav->alg_auth = SADB_X_AALG_AES128GMAC;
230 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_128;
231 break;
232 case AES_192_GMAC_KEY_LEN:
233 sav->alg_auth = SADB_X_AALG_AES192GMAC;
234 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_192;
235 break;
236 case AES_256_GMAC_KEY_LEN:
237 sav->alg_auth = SADB_X_AALG_AES256GMAC;
238 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_256;
239 break;
240 default:
241 DPRINTF(("%s: invalid key length %u"
242 "for algorithm %s\n", __func__,
243 keylen, txform->name));
244 return EINVAL;
245 }
246 bzero(&cria, sizeof(cria));
247 cria.cri_alg = sav->tdb_authalgxform->type;
248 cria.cri_key = sav->key_enc->key_data;
249 cria.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISGCM(sav) * 32;
250 }
251
252 /* Initialize crypto session. */
253 bzero(&crie, sizeof(crie));
254 crie.cri_alg = sav->tdb_encalgxform->type;
255 crie.cri_key = sav->key_enc->key_data;
256 crie.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISCTRORGCM(sav) * 32;
257
258 if (sav->tdb_authalgxform && sav->tdb_encalgxform) {
259 /* init both auth & enc */
260 crie.cri_next = &cria;
261 error = crypto_newsession(&sav->tdb_cryptoid,
262 &crie, V_crypto_support);
263 } else if (sav->tdb_encalgxform) {
264 error = crypto_newsession(&sav->tdb_cryptoid,
265 &crie, V_crypto_support);
266 } else if (sav->tdb_authalgxform) {
267 error = crypto_newsession(&sav->tdb_cryptoid,
268 &cria, V_crypto_support);
269 } else {
270 /* XXX cannot happen? */
271 DPRINTF(("%s: no encoding OR authentication xform!\n",
272 __func__));
273 error = EINVAL;
274 }
275 return error;
276 }
277
278 /*
279 * Paranoia.
280 */
281 static int
282 esp_zeroize(struct secasvar *sav)
283 {
284 /* NB: ah_zerorize free's the crypto session state */
285 int error = ah_zeroize(sav);
286
287 if (sav->key_enc)
288 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc));
289 sav->tdb_encalgxform = NULL;
290 sav->tdb_xform = NULL;
291 return error;
292 }
293
294 /*
295 * ESP input processing, called (eventually) through the protocol switch.
296 */
297 static int
298 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
299 {
300 char buf[128];
301 struct auth_hash *esph;
302 struct enc_xform *espx;
303 struct tdb_crypto *tc;
304 uint8_t *ivp;
305 int plen, alen, hlen;
306 struct newesp *esp;
307 struct cryptodesc *crde;
308 struct cryptop *crp;
309
310 IPSEC_ASSERT(sav != NULL, ("null SA"));
311 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform"));
312
313 /* Valid IP Packet length ? */
314 if ( (skip&3) || (m->m_pkthdr.len&3) ){
315 DPRINTF(("%s: misaligned packet, skip %u pkt len %u",
316 __func__, skip, m->m_pkthdr.len));
317 ESPSTAT_INC(esps_badilen);
318 m_freem(m);
319 return EINVAL;
320 }
321 /* XXX don't pullup, just copy header */
322 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp));
323
324 esph = sav->tdb_authalgxform;
325 espx = sav->tdb_encalgxform;
326
327 /* Determine the ESP header and auth length */
328 if (sav->flags & SADB_X_EXT_OLD)
329 hlen = sizeof (struct esp) + sav->ivlen;
330 else
331 hlen = sizeof (struct newesp) + sav->ivlen;
332
333 alen = xform_ah_authsize(esph);
334
335 /*
336 * Verify payload length is multiple of encryption algorithm
337 * block size.
338 *
339 * NB: This works for the null algorithm because the blocksize
340 * is 4 and all packets must be 4-byte aligned regardless
341 * of the algorithm.
342 */
343 plen = m->m_pkthdr.len - (skip + hlen + alen);
344 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) {
345 DPRINTF(("%s: payload of %d octets not a multiple of %d octets,"
346 " SA %s/%08lx\n", __func__, plen, espx->blocksize,
347 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
348 (u_long)ntohl(sav->spi)));
349 ESPSTAT_INC(esps_badilen);
350 m_freem(m);
351 return EINVAL;
352 }
353
354 /*
355 * Check sequence number.
356 */
357 if (esph != NULL && sav->replay != NULL &&
358 !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) {
359 DPRINTF(("%s: packet replay check for %s\n", __func__,
360 ipsec_logsastr(sav, buf, sizeof(buf)))); /*XXX*/
361 ESPSTAT_INC(esps_replay);
362 m_freem(m);
363 return ENOBUFS; /*XXX*/
364 }
365
366 /* Update the counters */
367 ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen));
368
369 /* Get crypto descriptors */
370 crp = crypto_getreq(esph && espx ? 2 : 1);
371 if (crp == NULL) {
372 DPRINTF(("%s: failed to acquire crypto descriptors\n",
373 __func__));
374 ESPSTAT_INC(esps_crypto);
375 m_freem(m);
376 return ENOBUFS;
377 }
378
379 /* Get IPsec-specific opaque pointer */
380 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen,
381 M_XDATA, M_NOWAIT | M_ZERO);
382 if (tc == NULL) {
383 crypto_freereq(crp);
384 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
385 ESPSTAT_INC(esps_crypto);
386 m_freem(m);
387 return ENOBUFS;
388 }
389
390 if (esph != NULL) {
391 struct cryptodesc *crda = crp->crp_desc;
392
393 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor"));
394
395 /* Authentication descriptor */
396 crda->crd_skip = skip;
397 if (SAV_ISGCM(sav))
398 crda->crd_len = 8; /* RFC4106 5, SPI + SN */
399 else
400 crda->crd_len = m->m_pkthdr.len - (skip + alen);
401 crda->crd_inject = m->m_pkthdr.len - alen;
402
403 crda->crd_alg = esph->type;
404
405 /* Copy the authenticator */
406 m_copydata(m, m->m_pkthdr.len - alen, alen,
407 (caddr_t) (tc + 1));
408
409 /* Chain authentication request */
410 crde = crda->crd_next;
411 } else {
412 crde = crp->crp_desc;
413 }
414
415 /* Crypto operation descriptor */
416 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */
417 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
418 crp->crp_buf = (caddr_t) m;
419 crp->crp_callback = esp_input_cb;
420 crp->crp_sid = sav->tdb_cryptoid;
421 crp->crp_opaque = (caddr_t) tc;
422
423 /* These are passed as-is to the callback */
424 tc->tc_spi = sav->spi;
425 tc->tc_dst = sav->sah->saidx.dst;
426 tc->tc_proto = sav->sah->saidx.proto;
427 tc->tc_protoff = protoff;
428 tc->tc_skip = skip;
429 KEY_ADDREFSA(sav);
430 tc->tc_sav = sav;
431
432 /* Decryption descriptor */
433 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor"));
434 crde->crd_skip = skip + hlen;
435 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
436 crde->crd_inject = skip + hlen - sav->ivlen;
437
438 if (SAV_ISCTRORGCM(sav)) {
439 ivp = &crde->crd_iv[0];
440
441 /* GCM IV Format: RFC4106 4 */
442 /* CTR IV Format: RFC3686 4 */
443 /* Salt is last four bytes of key, RFC4106 8.1 */
444 /* Nonce is last four bytes of key, RFC3686 5.1 */
445 memcpy(ivp, sav->key_enc->key_data +
446 _KEYLEN(sav->key_enc) - 4, 4);
447
448 if (SAV_ISCTR(sav)) {
449 /* Initial block counter is 1, RFC3686 4 */
450 be32enc(&ivp[sav->ivlen + 4], 1);
451 }
452
453 m_copydata(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]);
454 crde->crd_flags |= CRD_F_IV_EXPLICIT;
455 }
456
457 crde->crd_alg = espx->type;
458
459 return (crypto_dispatch(crp));
460 }
461
462 /*
463 * ESP input callback from the crypto driver.
464 */
465 static int
466 esp_input_cb(struct cryptop *crp)
467 {
468 char buf[128];
469 u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN];
470 int hlen, skip, protoff, error, alen;
471 struct mbuf *m;
472 struct cryptodesc *crd;
473 struct auth_hash *esph;
474 struct enc_xform *espx;
475 struct tdb_crypto *tc;
476 struct secasvar *sav;
477 struct secasindex *saidx;
478 caddr_t ptr;
479
480 crd = crp->crp_desc;
481 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!"));
482
483 tc = (struct tdb_crypto *) crp->crp_opaque;
484 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!"));
485 skip = tc->tc_skip;
486 protoff = tc->tc_protoff;
487 m = (struct mbuf *) crp->crp_buf;
488
489 sav = tc->tc_sav;
490 IPSEC_ASSERT(sav != NULL, ("null SA!"));
491
492 saidx = &sav->sah->saidx;
493 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
494 saidx->dst.sa.sa_family == AF_INET6,
495 ("unexpected protocol family %u", saidx->dst.sa.sa_family));
496
497 esph = sav->tdb_authalgxform;
498 espx = sav->tdb_encalgxform;
499
500 /* Check for crypto errors */
501 if (crp->crp_etype) {
502 /* Reset the session ID */
503 if (sav->tdb_cryptoid != 0)
504 sav->tdb_cryptoid = crp->crp_sid;
505
506 if (crp->crp_etype == EAGAIN)
507 return (crypto_dispatch(crp));
508
509 ESPSTAT_INC(esps_noxform);
510 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
511 error = crp->crp_etype;
512 goto bad;
513 }
514
515 /* Shouldn't happen... */
516 if (m == NULL) {
517 ESPSTAT_INC(esps_crypto);
518 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
519 error = EINVAL;
520 goto bad;
521 }
522 ESPSTAT_INC(esps_hist[sav->alg_enc]);
523
524 /* If authentication was performed, check now. */
525 if (esph != NULL) {
526 alen = xform_ah_authsize(esph);
527 AHSTAT_INC(ahs_hist[sav->alg_auth]);
528 /* Copy the authenticator from the packet */
529 m_copydata(m, m->m_pkthdr.len - alen, alen, aalg);
530 ptr = (caddr_t) (tc + 1);
531
532 /* Verify authenticator */
533 if (timingsafe_bcmp(ptr, aalg, alen) != 0) {
534 DPRINTF(("%s: authentication hash mismatch for "
535 "packet in SA %s/%08lx\n", __func__,
536 ipsec_address(&saidx->dst, buf, sizeof(buf)),
537 (u_long) ntohl(sav->spi)));
538 ESPSTAT_INC(esps_badauth);
539 error = EACCES;
540 goto bad;
541 }
542
543 /* Remove trailing authenticator */
544 m_adj(m, -alen);
545 }
546
547 /* Release the crypto descriptors */
548 free(tc, M_XDATA), tc = NULL;
549 crypto_freereq(crp), crp = NULL;
550
551 /*
552 * Packet is now decrypted.
553 */
554 m->m_flags |= M_DECRYPTED;
555
556 /*
557 * Update replay sequence number, if appropriate.
558 */
559 if (sav->replay) {
560 u_int32_t seq;
561
562 m_copydata(m, skip + offsetof(struct newesp, esp_seq),
563 sizeof (seq), (caddr_t) &seq);
564 if (ipsec_updatereplay(ntohl(seq), sav)) {
565 DPRINTF(("%s: packet replay check for %s\n", __func__,
566 ipsec_logsastr(sav, buf, sizeof(buf))));
567 ESPSTAT_INC(esps_replay);
568 error = ENOBUFS;
569 goto bad;
570 }
571 }
572
573 /* Determine the ESP header length */
574 if (sav->flags & SADB_X_EXT_OLD)
575 hlen = sizeof (struct esp) + sav->ivlen;
576 else
577 hlen = sizeof (struct newesp) + sav->ivlen;
578
579 /* Remove the ESP header and IV from the mbuf. */
580 error = m_striphdr(m, skip, hlen);
581 if (error) {
582 ESPSTAT_INC(esps_hdrops);
583 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__,
584 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
585 (u_long) ntohl(sav->spi)));
586 goto bad;
587 }
588
589 /* Save the last three bytes of decrypted data */
590 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree);
591
592 /* Verify pad length */
593 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) {
594 ESPSTAT_INC(esps_badilen);
595 DPRINTF(("%s: invalid padding length %d for %u byte packet "
596 "in SA %s/%08lx\n", __func__, lastthree[1],
597 m->m_pkthdr.len - skip,
598 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
599 (u_long) ntohl(sav->spi)));
600 error = EINVAL;
601 goto bad;
602 }
603
604 /* Verify correct decryption by checking the last padding bytes */
605 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) {
606 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) {
607 ESPSTAT_INC(esps_badenc);
608 DPRINTF(("%s: decryption failed for packet in "
609 "SA %s/%08lx\n", __func__, ipsec_address(
610 &sav->sah->saidx.dst, buf, sizeof(buf)),
611 (u_long) ntohl(sav->spi)));
612 error = EINVAL;
613 goto bad;
614 }
615 }
616
617 /* Trim the mbuf chain to remove trailing authenticator and padding */
618 m_adj(m, -(lastthree[1] + 2));
619
620 /* Restore the Next Protocol field */
621 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2);
622
623 switch (saidx->dst.sa.sa_family) {
624 #ifdef INET6
625 case AF_INET6:
626 error = ipsec6_common_input_cb(m, sav, skip, protoff);
627 break;
628 #endif
629 #ifdef INET
630 case AF_INET:
631 error = ipsec4_common_input_cb(m, sav, skip, protoff);
632 break;
633 #endif
634 default:
635 panic("%s: Unexpected address family: %d saidx=%p", __func__,
636 saidx->dst.sa.sa_family, saidx);
637 }
638
639 KEY_FREESAV(&sav);
640 return error;
641 bad:
642 if (sav)
643 KEY_FREESAV(&sav);
644 if (m != NULL)
645 m_freem(m);
646 if (tc != NULL)
647 free(tc, M_XDATA);
648 if (crp != NULL)
649 crypto_freereq(crp);
650 return error;
651 }
652
653 /*
654 * ESP output routine, called by ipsec[46]_process_packet().
655 */
656 static int
657 esp_output(struct mbuf *m, struct ipsecrequest *isr, struct mbuf **mp,
658 int skip, int protoff)
659 {
660 char buf[INET6_ADDRSTRLEN];
661 struct enc_xform *espx;
662 struct auth_hash *esph;
663 uint8_t *ivp;
664 uint64_t cntr;
665 int hlen, rlen, padding, blks, alen, i, roff;
666 struct mbuf *mo = (struct mbuf *) NULL;
667 struct tdb_crypto *tc;
668 struct secasvar *sav;
669 struct secasindex *saidx;
670 unsigned char *pad;
671 u_int8_t prot;
672 int error, maxpacketsize;
673
674 struct cryptodesc *crde = NULL, *crda = NULL;
675 struct cryptop *crp;
676
677 sav = isr->sav;
678 IPSEC_ASSERT(sav != NULL, ("null SA"));
679 esph = sav->tdb_authalgxform;
680 espx = sav->tdb_encalgxform;
681 IPSEC_ASSERT(espx != NULL, ("null encoding xform"));
682
683 if (sav->flags & SADB_X_EXT_OLD)
684 hlen = sizeof (struct esp) + sav->ivlen;
685 else
686 hlen = sizeof (struct newesp) + sav->ivlen;
687
688 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */
689 /*
690 * RFC4303 2.4 Requires 4 byte alignment.
691 */
692 blks = MAX(4, espx->blocksize); /* Cipher blocksize */
693
694 /* XXX clamp padding length a la KAME??? */
695 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;
696
697 alen = xform_ah_authsize(esph);
698
699 ESPSTAT_INC(esps_output);
700
701 saidx = &sav->sah->saidx;
702 /* Check for maximum packet size violations. */
703 switch (saidx->dst.sa.sa_family) {
704 #ifdef INET
705 case AF_INET:
706 maxpacketsize = IP_MAXPACKET;
707 break;
708 #endif /* INET */
709 #ifdef INET6
710 case AF_INET6:
711 maxpacketsize = IPV6_MAXPACKET;
712 break;
713 #endif /* INET6 */
714 default:
715 DPRINTF(("%s: unknown/unsupported protocol "
716 "family %d, SA %s/%08lx\n", __func__,
717 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst,
718 buf, sizeof(buf)), (u_long) ntohl(sav->spi)));
719 ESPSTAT_INC(esps_nopf);
720 error = EPFNOSUPPORT;
721 goto bad;
722 }
723 DPRINTF(("%s: skip %d hlen %d rlen %d padding %d alen %d blksd %d\n",
724 __func__, skip, hlen, rlen, padding, alen, blks));
725 if (skip + hlen + rlen + padding + alen > maxpacketsize) {
726 DPRINTF(("%s: packet in SA %s/%08lx got too big "
727 "(len %u, max len %u)\n", __func__,
728 ipsec_address(&saidx->dst, buf, sizeof(buf)),
729 (u_long) ntohl(sav->spi),
730 skip + hlen + rlen + padding + alen, maxpacketsize));
731 ESPSTAT_INC(esps_toobig);
732 error = EMSGSIZE;
733 goto bad;
734 }
735
736 /* Update the counters. */
737 ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip);
738
739 m = m_unshare(m, M_NOWAIT);
740 if (m == NULL) {
741 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__,
742 ipsec_address(&saidx->dst, buf, sizeof(buf)),
743 (u_long) ntohl(sav->spi)));
744 ESPSTAT_INC(esps_hdrops);
745 error = ENOBUFS;
746 goto bad;
747 }
748
749 /* Inject ESP header. */
750 mo = m_makespace(m, skip, hlen, &roff);
751 if (mo == NULL) {
752 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n",
753 __func__, hlen, ipsec_address(&saidx->dst, buf,
754 sizeof(buf)), (u_long) ntohl(sav->spi)));
755 ESPSTAT_INC(esps_hdrops); /* XXX diffs from openbsd */
756 error = ENOBUFS;
757 goto bad;
758 }
759
760 /* Initialize ESP header. */
761 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t));
762 if (sav->replay) {
763 u_int32_t replay;
764
765 #ifdef REGRESSION
766 /* Emulate replay attack when ipsec_replay is TRUE. */
767 if (!V_ipsec_replay)
768 #endif
769 sav->replay->count++;
770 replay = htonl(sav->replay->count);
771 bcopy((caddr_t) &replay,
772 mtod(mo, caddr_t) + roff + sizeof(u_int32_t),
773 sizeof(u_int32_t));
774 }
775
776 /*
777 * Add padding -- better to do it ourselves than use the crypto engine,
778 * although if/when we support compression, we'd have to do that.
779 */
780 pad = (u_char *) m_pad(m, padding + alen);
781 if (pad == NULL) {
782 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__,
783 ipsec_address(&saidx->dst, buf, sizeof(buf)),
784 (u_long) ntohl(sav->spi)));
785 m = NULL; /* NB: free'd by m_pad */
786 error = ENOBUFS;
787 goto bad;
788 }
789
790 /*
791 * Add padding: random, zero, or self-describing.
792 * XXX catch unexpected setting
793 */
794 switch (sav->flags & SADB_X_EXT_PMASK) {
795 case SADB_X_EXT_PRAND:
796 (void) read_random(pad, padding - 2);
797 break;
798 case SADB_X_EXT_PZERO:
799 bzero(pad, padding - 2);
800 break;
801 case SADB_X_EXT_PSEQ:
802 for (i = 0; i < padding - 2; i++)
803 pad[i] = i+1;
804 break;
805 }
806
807 /* Fix padding length and Next Protocol in padding itself. */
808 pad[padding - 2] = padding - 2;
809 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1);
810
811 /* Fix Next Protocol in IPv4/IPv6 header. */
812 prot = IPPROTO_ESP;
813 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot);
814
815 /* Get crypto descriptors. */
816 crp = crypto_getreq(esph != NULL ? 2 : 1);
817 if (crp == NULL) {
818 DPRINTF(("%s: failed to acquire crypto descriptors\n",
819 __func__));
820 ESPSTAT_INC(esps_crypto);
821 error = ENOBUFS;
822 goto bad;
823 }
824
825 /* IPsec-specific opaque crypto info. */
826 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
827 M_XDATA, M_NOWAIT|M_ZERO);
828 if (tc == NULL) {
829 crypto_freereq(crp);
830 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
831 ESPSTAT_INC(esps_crypto);
832 error = ENOBUFS;
833 goto bad;
834 }
835
836 crde = crp->crp_desc;
837 crda = crde->crd_next;
838
839 /* Encryption descriptor. */
840 crde->crd_skip = skip + hlen;
841 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
842 crde->crd_flags = CRD_F_ENCRYPT;
843 crde->crd_inject = skip + hlen - sav->ivlen;
844
845 /* Encryption operation. */
846 crde->crd_alg = espx->type;
847 if (SAV_ISCTRORGCM(sav)) {
848 ivp = &crde->crd_iv[0];
849
850 /* GCM IV Format: RFC4106 4 */
851 /* CTR IV Format: RFC3686 4 */
852 /* Salt is last four bytes of key, RFC4106 8.1 */
853 /* Nonce is last four bytes of key, RFC3686 5.1 */
854 memcpy(ivp, sav->key_enc->key_data +
855 _KEYLEN(sav->key_enc) - 4, 4);
856 SECASVAR_LOCK(sav);
857 cntr = sav->cntr++;
858 SECASVAR_UNLOCK(sav);
859 be64enc(&ivp[4], cntr);
860
861 if (SAV_ISCTR(sav)) {
862 /* Initial block counter is 1, RFC3686 4 */
863 be32enc(&ivp[sav->ivlen + 4], 1);
864 }
865
866 m_copyback(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]);
867 crde->crd_flags |= CRD_F_IV_EXPLICIT|CRD_F_IV_PRESENT;
868 }
869
870 /* Callback parameters */
871 key_addref(isr->sp);
872 tc->tc_isr = isr;
873 KEY_ADDREFSA(sav);
874 tc->tc_sav = sav;
875 tc->tc_spi = sav->spi;
876 tc->tc_dst = saidx->dst;
877 tc->tc_proto = saidx->proto;
878
879 /* Crypto operation descriptor. */
880 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
881 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
882 crp->crp_buf = (caddr_t) m;
883 crp->crp_callback = esp_output_cb;
884 crp->crp_opaque = (caddr_t) tc;
885 crp->crp_sid = sav->tdb_cryptoid;
886
887 if (esph) {
888 /* Authentication descriptor. */
889 crda->crd_alg = esph->type;
890 crda->crd_skip = skip;
891 if (SAV_ISGCM(sav))
892 crda->crd_len = 8; /* RFC4106 5, SPI + SN */
893 else
894 crda->crd_len = m->m_pkthdr.len - (skip + alen);
895 crda->crd_inject = m->m_pkthdr.len - alen;
896 }
897
898 return crypto_dispatch(crp);
899 bad:
900 if (m)
901 m_freem(m);
902 return (error);
903 }
904
905 /*
906 * ESP output callback from the crypto driver.
907 */
908 static int
909 esp_output_cb(struct cryptop *crp)
910 {
911 char buf[INET6_ADDRSTRLEN];
912 struct tdb_crypto *tc;
913 struct ipsecrequest *isr;
914 struct secasvar *sav;
915 struct mbuf *m;
916 int error;
917
918 tc = (struct tdb_crypto *) crp->crp_opaque;
919 IPSEC_ASSERT(tc != NULL, ("null opaque data area!"));
920 m = (struct mbuf *) crp->crp_buf;
921
922 isr = tc->tc_isr;
923 IPSEC_ASSERT(isr->sp != NULL, ("NULL isr->sp"));
924 IPSECREQUEST_LOCK(isr);
925 sav = tc->tc_sav;
926
927 /* With the isr lock released, SA pointer may have changed. */
928 if (sav != isr->sav) {
929 ESPSTAT_INC(esps_notdb);
930 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n",
931 __func__, ipsec_address(&tc->tc_dst, buf, sizeof(buf)),
932 (u_long) ntohl(tc->tc_spi), tc->tc_proto));
933 error = ENOBUFS; /*XXX*/
934 goto bad;
935 }
936
937 /* Check for crypto errors. */
938 if (crp->crp_etype) {
939 /* Reset session ID. */
940 if (sav->tdb_cryptoid != 0)
941 sav->tdb_cryptoid = crp->crp_sid;
942
943 if (crp->crp_etype == EAGAIN) {
944 IPSECREQUEST_UNLOCK(isr);
945 return (crypto_dispatch(crp));
946 }
947
948 ESPSTAT_INC(esps_noxform);
949 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
950 error = crp->crp_etype;
951 goto bad;
952 }
953
954 /* Shouldn't happen... */
955 if (m == NULL) {
956 ESPSTAT_INC(esps_crypto);
957 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
958 error = EINVAL;
959 goto bad;
960 }
961 ESPSTAT_INC(esps_hist[sav->alg_enc]);
962 if (sav->tdb_authalgxform != NULL)
963 AHSTAT_INC(ahs_hist[sav->alg_auth]);
964
965 /* Release crypto descriptors. */
966 free(tc, M_XDATA);
967 crypto_freereq(crp);
968
969 #ifdef REGRESSION
970 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
971 if (V_ipsec_integrity) {
972 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN];
973 struct auth_hash *esph;
974
975 /*
976 * Corrupt HMAC if we want to test integrity verification of
977 * the other side.
978 */
979 esph = sav->tdb_authalgxform;
980 if (esph != NULL) {
981 int alen;
982
983 alen = xform_ah_authsize(esph);
984 m_copyback(m, m->m_pkthdr.len - alen,
985 alen, ipseczeroes);
986 }
987 }
988 #endif
989
990 /* NB: m is reclaimed by ipsec_process_done. */
991 error = ipsec_process_done(m, isr);
992 KEY_FREESAV(&sav);
993 IPSECREQUEST_UNLOCK(isr);
994 KEY_FREESP(&isr->sp);
995 return (error);
996 bad:
997 if (sav)
998 KEY_FREESAV(&sav);
999 IPSECREQUEST_UNLOCK(isr);
1000 KEY_FREESP(&isr->sp);
1001 if (m)
1002 m_freem(m);
1003 free(tc, M_XDATA);
1004 crypto_freereq(crp);
1005 return (error);
1006 }
1007
1008 static struct xformsw esp_xformsw = {
1009 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP",
1010 esp_init, esp_zeroize, esp_input,
1011 esp_output
1012 };
1013
1014 static void
1015 esp_attach(void)
1016 {
1017
1018 xform_register(&esp_xformsw);
1019 }
1020 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL);
Cache object: 974f37dea40f8f31ad101a10bc10d10d
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