1 /* $FreeBSD: releng/11.1/sys/netipsec/xform_esp.c 319599 2017-06-05 11:11:07Z 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/mutex.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 size_t
101 esp_hdrsiz(struct secasvar *sav)
102 {
103 size_t size;
104
105 if (sav != NULL) {
106 /*XXX not right for null algorithm--does it matter??*/
107 IPSEC_ASSERT(sav->tdb_encalgxform != NULL,
108 ("SA with null xform"));
109 if (sav->flags & SADB_X_EXT_OLD)
110 size = sizeof (struct esp);
111 else
112 size = sizeof (struct newesp);
113 size += sav->tdb_encalgxform->blocksize + 9;
114 /*XXX need alg check???*/
115 if (sav->tdb_authalgxform != NULL && sav->replay)
116 size += ah_hdrsiz(sav);
117 } else {
118 /*
119 * base header size
120 * + max iv length for CBC mode
121 * + max pad length
122 * + sizeof (pad length field)
123 * + sizeof (next header field)
124 * + max icv supported.
125 */
126 size = sizeof (struct newesp) + EALG_MAX_BLOCK_LEN + 9 + 16;
127 }
128 return size;
129 }
130
131 /*
132 * esp_init() is called when an SPI is being set up.
133 */
134 static int
135 esp_init(struct secasvar *sav, struct xformsw *xsp)
136 {
137 const struct enc_xform *txform;
138 struct cryptoini cria, crie;
139 int keylen;
140 int error;
141
142 txform = enc_algorithm_lookup(sav->alg_enc);
143 if (txform == NULL) {
144 DPRINTF(("%s: unsupported encryption algorithm %d\n",
145 __func__, sav->alg_enc));
146 return EINVAL;
147 }
148 if (sav->key_enc == NULL) {
149 DPRINTF(("%s: no encoding key for %s algorithm\n",
150 __func__, txform->name));
151 return EINVAL;
152 }
153 if ((sav->flags & (SADB_X_EXT_OLD | SADB_X_EXT_IV4B)) ==
154 SADB_X_EXT_IV4B) {
155 DPRINTF(("%s: 4-byte IV not supported with protocol\n",
156 __func__));
157 return EINVAL;
158 }
159 /* subtract off the salt, RFC4106, 8.1 and RFC3686, 5.1 */
160 keylen = _KEYLEN(sav->key_enc) - SAV_ISCTRORGCM(sav) * 4;
161 if (txform->minkey > keylen || keylen > txform->maxkey) {
162 DPRINTF(("%s: invalid key length %u, must be in the range "
163 "[%u..%u] for algorithm %s\n", __func__,
164 keylen, txform->minkey, txform->maxkey,
165 txform->name));
166 return EINVAL;
167 }
168
169 if (SAV_ISCTRORGCM(sav))
170 sav->ivlen = 8; /* RFC4106 3.1 and RFC3686 3.1 */
171 else
172 sav->ivlen = txform->ivsize;
173
174 /*
175 * Setup AH-related state.
176 */
177 if (sav->alg_auth != 0) {
178 error = ah_init0(sav, xsp, &cria);
179 if (error)
180 return error;
181 }
182
183 /* NB: override anything set in ah_init0 */
184 sav->tdb_xform = xsp;
185 sav->tdb_encalgxform = txform;
186
187 /*
188 * Whenever AES-GCM is used for encryption, one
189 * of the AES authentication algorithms is chosen
190 * as well, based on the key size.
191 */
192 if (sav->alg_enc == SADB_X_EALG_AESGCM16) {
193 switch (keylen) {
194 case AES_128_GMAC_KEY_LEN:
195 sav->alg_auth = SADB_X_AALG_AES128GMAC;
196 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_128;
197 break;
198 case AES_192_GMAC_KEY_LEN:
199 sav->alg_auth = SADB_X_AALG_AES192GMAC;
200 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_192;
201 break;
202 case AES_256_GMAC_KEY_LEN:
203 sav->alg_auth = SADB_X_AALG_AES256GMAC;
204 sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_256;
205 break;
206 default:
207 DPRINTF(("%s: invalid key length %u"
208 "for algorithm %s\n", __func__,
209 keylen, txform->name));
210 return EINVAL;
211 }
212 bzero(&cria, sizeof(cria));
213 cria.cri_alg = sav->tdb_authalgxform->type;
214 cria.cri_key = sav->key_enc->key_data;
215 cria.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISGCM(sav) * 32;
216 }
217
218 /* Initialize crypto session. */
219 bzero(&crie, sizeof(crie));
220 crie.cri_alg = sav->tdb_encalgxform->type;
221 crie.cri_key = sav->key_enc->key_data;
222 crie.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISCTRORGCM(sav) * 32;
223
224 if (sav->tdb_authalgxform && sav->tdb_encalgxform) {
225 /* init both auth & enc */
226 crie.cri_next = &cria;
227 error = crypto_newsession(&sav->tdb_cryptoid,
228 &crie, V_crypto_support);
229 } else if (sav->tdb_encalgxform) {
230 error = crypto_newsession(&sav->tdb_cryptoid,
231 &crie, V_crypto_support);
232 } else if (sav->tdb_authalgxform) {
233 error = crypto_newsession(&sav->tdb_cryptoid,
234 &cria, V_crypto_support);
235 } else {
236 /* XXX cannot happen? */
237 DPRINTF(("%s: no encoding OR authentication xform!\n",
238 __func__));
239 error = EINVAL;
240 }
241 return error;
242 }
243
244 /*
245 * Paranoia.
246 */
247 static int
248 esp_zeroize(struct secasvar *sav)
249 {
250 /* NB: ah_zerorize free's the crypto session state */
251 int error = ah_zeroize(sav);
252
253 if (sav->key_enc)
254 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc));
255 sav->tdb_encalgxform = NULL;
256 sav->tdb_xform = NULL;
257 return error;
258 }
259
260 /*
261 * ESP input processing, called (eventually) through the protocol switch.
262 */
263 static int
264 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
265 {
266 IPSEC_DEBUG_DECLARE(char buf[128]);
267 const struct auth_hash *esph;
268 const struct enc_xform *espx;
269 struct xform_data *xd;
270 struct cryptodesc *crde;
271 struct cryptop *crp;
272 struct newesp *esp;
273 uint8_t *ivp;
274 uint64_t cryptoid;
275 int alen, error, hlen, plen;
276
277 IPSEC_ASSERT(sav != NULL, ("null SA"));
278 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform"));
279
280 error = EINVAL;
281 /* Valid IP Packet length ? */
282 if ( (skip&3) || (m->m_pkthdr.len&3) ){
283 DPRINTF(("%s: misaligned packet, skip %u pkt len %u",
284 __func__, skip, m->m_pkthdr.len));
285 ESPSTAT_INC(esps_badilen);
286 goto bad;
287 }
288 /* XXX don't pullup, just copy header */
289 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp));
290
291 esph = sav->tdb_authalgxform;
292 espx = sav->tdb_encalgxform;
293
294 /* Determine the ESP header and auth length */
295 if (sav->flags & SADB_X_EXT_OLD)
296 hlen = sizeof (struct esp) + sav->ivlen;
297 else
298 hlen = sizeof (struct newesp) + sav->ivlen;
299
300 alen = xform_ah_authsize(esph);
301
302 /*
303 * Verify payload length is multiple of encryption algorithm
304 * block size.
305 *
306 * NB: This works for the null algorithm because the blocksize
307 * is 4 and all packets must be 4-byte aligned regardless
308 * of the algorithm.
309 */
310 plen = m->m_pkthdr.len - (skip + hlen + alen);
311 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) {
312 DPRINTF(("%s: payload of %d octets not a multiple of %d octets,"
313 " SA %s/%08lx\n", __func__, plen, espx->blocksize,
314 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
315 (u_long)ntohl(sav->spi)));
316 ESPSTAT_INC(esps_badilen);
317 goto bad;
318 }
319
320 /*
321 * Check sequence number.
322 */
323 SECASVAR_LOCK(sav);
324 if (esph != NULL && sav->replay != NULL && sav->replay->wsize != 0) {
325 if (ipsec_chkreplay(ntohl(esp->esp_seq), sav) == 0) {
326 SECASVAR_UNLOCK(sav);
327 DPRINTF(("%s: packet replay check for %s\n", __func__,
328 ipsec_sa2str(sav, buf, sizeof(buf))));
329 ESPSTAT_INC(esps_replay);
330 error = EACCES;
331 goto bad;
332 }
333 }
334 cryptoid = sav->tdb_cryptoid;
335 SECASVAR_UNLOCK(sav);
336
337 /* Update the counters */
338 ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen));
339
340 /* Get crypto descriptors */
341 crp = crypto_getreq(esph && espx ? 2 : 1);
342 if (crp == NULL) {
343 DPRINTF(("%s: failed to acquire crypto descriptors\n",
344 __func__));
345 ESPSTAT_INC(esps_crypto);
346 error = ENOBUFS;
347 goto bad;
348 }
349
350 /* Get IPsec-specific opaque pointer */
351 xd = malloc(sizeof(*xd) + alen, M_XDATA, M_NOWAIT | M_ZERO);
352 if (xd == NULL) {
353 DPRINTF(("%s: failed to allocate xform_data\n", __func__));
354 ESPSTAT_INC(esps_crypto);
355 crypto_freereq(crp);
356 error = ENOBUFS;
357 goto bad;
358 }
359
360 if (esph != NULL) {
361 struct cryptodesc *crda = crp->crp_desc;
362
363 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor"));
364
365 /* Authentication descriptor */
366 crda->crd_skip = skip;
367 if (SAV_ISGCM(sav))
368 crda->crd_len = 8; /* RFC4106 5, SPI + SN */
369 else
370 crda->crd_len = m->m_pkthdr.len - (skip + alen);
371 crda->crd_inject = m->m_pkthdr.len - alen;
372
373 crda->crd_alg = esph->type;
374
375 /* Copy the authenticator */
376 m_copydata(m, m->m_pkthdr.len - alen, alen,
377 (caddr_t) (xd + 1));
378
379 /* Chain authentication request */
380 crde = crda->crd_next;
381 } else {
382 crde = crp->crp_desc;
383 }
384
385 /* Crypto operation descriptor */
386 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */
387 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
388 crp->crp_buf = (caddr_t) m;
389 crp->crp_callback = esp_input_cb;
390 crp->crp_sid = cryptoid;
391 crp->crp_opaque = (caddr_t) xd;
392
393 /* These are passed as-is to the callback */
394 xd->sav = sav;
395 xd->protoff = protoff;
396 xd->skip = skip;
397 xd->cryptoid = cryptoid;
398
399 /* Decryption descriptor */
400 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor"));
401 crde->crd_skip = skip + hlen;
402 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
403 crde->crd_inject = skip + hlen - sav->ivlen;
404
405 if (SAV_ISCTRORGCM(sav)) {
406 ivp = &crde->crd_iv[0];
407
408 /* GCM IV Format: RFC4106 4 */
409 /* CTR IV Format: RFC3686 4 */
410 /* Salt is last four bytes of key, RFC4106 8.1 */
411 /* Nonce is last four bytes of key, RFC3686 5.1 */
412 memcpy(ivp, sav->key_enc->key_data +
413 _KEYLEN(sav->key_enc) - 4, 4);
414
415 if (SAV_ISCTR(sav)) {
416 /* Initial block counter is 1, RFC3686 4 */
417 be32enc(&ivp[sav->ivlen + 4], 1);
418 }
419
420 m_copydata(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]);
421 crde->crd_flags |= CRD_F_IV_EXPLICIT;
422 }
423
424 crde->crd_alg = espx->type;
425
426 return (crypto_dispatch(crp));
427 bad:
428 m_freem(m);
429 key_freesav(&sav);
430 return (error);
431 }
432
433 /*
434 * ESP input callback from the crypto driver.
435 */
436 static int
437 esp_input_cb(struct cryptop *crp)
438 {
439 IPSEC_DEBUG_DECLARE(char buf[128]);
440 u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN];
441 const struct auth_hash *esph;
442 const struct enc_xform *espx;
443 struct mbuf *m;
444 struct cryptodesc *crd;
445 struct xform_data *xd;
446 struct secasvar *sav;
447 struct secasindex *saidx;
448 caddr_t ptr;
449 uint64_t cryptoid;
450 int hlen, skip, protoff, error, alen;
451
452 crd = crp->crp_desc;
453 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!"));
454
455 m = (struct mbuf *) crp->crp_buf;
456 xd = (struct xform_data *) crp->crp_opaque;
457 sav = xd->sav;
458 skip = xd->skip;
459 protoff = xd->protoff;
460 cryptoid = xd->cryptoid;
461 saidx = &sav->sah->saidx;
462 esph = sav->tdb_authalgxform;
463 espx = sav->tdb_encalgxform;
464
465 /* Check for crypto errors */
466 if (crp->crp_etype) {
467 if (crp->crp_etype == EAGAIN) {
468 /* Reset the session ID */
469 if (ipsec_updateid(sav, &crp->crp_sid, &cryptoid) != 0)
470 crypto_freesession(cryptoid);
471 xd->cryptoid = crp->crp_sid;
472 return (crypto_dispatch(crp));
473 }
474 ESPSTAT_INC(esps_noxform);
475 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
476 error = crp->crp_etype;
477 goto bad;
478 }
479
480 /* Shouldn't happen... */
481 if (m == NULL) {
482 ESPSTAT_INC(esps_crypto);
483 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
484 error = EINVAL;
485 goto bad;
486 }
487 ESPSTAT_INC(esps_hist[sav->alg_enc]);
488
489 /* If authentication was performed, check now. */
490 if (esph != NULL) {
491 alen = xform_ah_authsize(esph);
492 AHSTAT_INC(ahs_hist[sav->alg_auth]);
493 /* Copy the authenticator from the packet */
494 m_copydata(m, m->m_pkthdr.len - alen, alen, aalg);
495 ptr = (caddr_t) (xd + 1);
496
497 /* Verify authenticator */
498 if (timingsafe_bcmp(ptr, aalg, alen) != 0) {
499 DPRINTF(("%s: authentication hash mismatch for "
500 "packet in SA %s/%08lx\n", __func__,
501 ipsec_address(&saidx->dst, buf, sizeof(buf)),
502 (u_long) ntohl(sav->spi)));
503 ESPSTAT_INC(esps_badauth);
504 error = EACCES;
505 goto bad;
506 }
507 m->m_flags |= M_AUTHIPDGM;
508 /* Remove trailing authenticator */
509 m_adj(m, -alen);
510 }
511
512 /* Release the crypto descriptors */
513 free(xd, M_XDATA), xd = NULL;
514 crypto_freereq(crp), crp = NULL;
515
516 /*
517 * Packet is now decrypted.
518 */
519 m->m_flags |= M_DECRYPTED;
520
521 /*
522 * Update replay sequence number, if appropriate.
523 */
524 if (sav->replay) {
525 u_int32_t seq;
526
527 m_copydata(m, skip + offsetof(struct newesp, esp_seq),
528 sizeof (seq), (caddr_t) &seq);
529 SECASVAR_LOCK(sav);
530 if (ipsec_updatereplay(ntohl(seq), sav)) {
531 SECASVAR_UNLOCK(sav);
532 DPRINTF(("%s: packet replay check for %s\n", __func__,
533 ipsec_sa2str(sav, buf, sizeof(buf))));
534 ESPSTAT_INC(esps_replay);
535 error = EACCES;
536 goto bad;
537 }
538 SECASVAR_UNLOCK(sav);
539 }
540
541 /* Determine the ESP header length */
542 if (sav->flags & SADB_X_EXT_OLD)
543 hlen = sizeof (struct esp) + sav->ivlen;
544 else
545 hlen = sizeof (struct newesp) + sav->ivlen;
546
547 /* Remove the ESP header and IV from the mbuf. */
548 error = m_striphdr(m, skip, hlen);
549 if (error) {
550 ESPSTAT_INC(esps_hdrops);
551 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__,
552 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
553 (u_long) ntohl(sav->spi)));
554 goto bad;
555 }
556
557 /* Save the last three bytes of decrypted data */
558 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree);
559
560 /* Verify pad length */
561 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) {
562 ESPSTAT_INC(esps_badilen);
563 DPRINTF(("%s: invalid padding length %d for %u byte packet "
564 "in SA %s/%08lx\n", __func__, lastthree[1],
565 m->m_pkthdr.len - skip,
566 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
567 (u_long) ntohl(sav->spi)));
568 error = EINVAL;
569 goto bad;
570 }
571
572 /* Verify correct decryption by checking the last padding bytes */
573 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) {
574 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) {
575 ESPSTAT_INC(esps_badenc);
576 DPRINTF(("%s: decryption failed for packet in "
577 "SA %s/%08lx\n", __func__, ipsec_address(
578 &sav->sah->saidx.dst, buf, sizeof(buf)),
579 (u_long) ntohl(sav->spi)));
580 error = EINVAL;
581 goto bad;
582 }
583 }
584
585 /* Trim the mbuf chain to remove trailing authenticator and padding */
586 m_adj(m, -(lastthree[1] + 2));
587
588 /* Restore the Next Protocol field */
589 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2);
590
591 switch (saidx->dst.sa.sa_family) {
592 #ifdef INET6
593 case AF_INET6:
594 error = ipsec6_common_input_cb(m, sav, skip, protoff);
595 break;
596 #endif
597 #ifdef INET
598 case AF_INET:
599 error = ipsec4_common_input_cb(m, sav, skip, protoff);
600 break;
601 #endif
602 default:
603 panic("%s: Unexpected address family: %d saidx=%p", __func__,
604 saidx->dst.sa.sa_family, saidx);
605 }
606 return error;
607 bad:
608 if (sav != NULL)
609 key_freesav(&sav);
610 if (m != NULL)
611 m_freem(m);
612 if (xd != NULL)
613 free(xd, M_XDATA);
614 if (crp != NULL)
615 crypto_freereq(crp);
616 return error;
617 }
618 /*
619 * ESP output routine, called by ipsec[46]_perform_request().
620 */
621 static int
622 esp_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav,
623 u_int idx, int skip, int protoff)
624 {
625 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
626 struct cryptodesc *crde = NULL, *crda = NULL;
627 struct cryptop *crp;
628 const struct auth_hash *esph;
629 const struct enc_xform *espx;
630 struct mbuf *mo = NULL;
631 struct xform_data *xd;
632 struct secasindex *saidx;
633 unsigned char *pad;
634 uint8_t *ivp;
635 uint64_t cntr, cryptoid;
636 int hlen, rlen, padding, blks, alen, i, roff;
637 int error, maxpacketsize;
638 uint8_t prot;
639
640 IPSEC_ASSERT(sav != NULL, ("null SA"));
641 esph = sav->tdb_authalgxform;
642 espx = sav->tdb_encalgxform;
643 IPSEC_ASSERT(espx != NULL, ("null encoding xform"));
644
645 if (sav->flags & SADB_X_EXT_OLD)
646 hlen = sizeof (struct esp) + sav->ivlen;
647 else
648 hlen = sizeof (struct newesp) + sav->ivlen;
649
650 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */
651 /*
652 * RFC4303 2.4 Requires 4 byte alignment.
653 */
654 blks = MAX(4, espx->blocksize); /* Cipher blocksize */
655
656 /* XXX clamp padding length a la KAME??? */
657 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;
658
659 alen = xform_ah_authsize(esph);
660
661 ESPSTAT_INC(esps_output);
662
663 saidx = &sav->sah->saidx;
664 /* Check for maximum packet size violations. */
665 switch (saidx->dst.sa.sa_family) {
666 #ifdef INET
667 case AF_INET:
668 maxpacketsize = IP_MAXPACKET;
669 break;
670 #endif /* INET */
671 #ifdef INET6
672 case AF_INET6:
673 maxpacketsize = IPV6_MAXPACKET;
674 break;
675 #endif /* INET6 */
676 default:
677 DPRINTF(("%s: unknown/unsupported protocol "
678 "family %d, SA %s/%08lx\n", __func__,
679 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst,
680 buf, sizeof(buf)), (u_long) ntohl(sav->spi)));
681 ESPSTAT_INC(esps_nopf);
682 error = EPFNOSUPPORT;
683 goto bad;
684 }
685 /*
686 DPRINTF(("%s: skip %d hlen %d rlen %d padding %d alen %d blksd %d\n",
687 __func__, skip, hlen, rlen, padding, alen, blks)); */
688 if (skip + hlen + rlen + padding + alen > maxpacketsize) {
689 DPRINTF(("%s: packet in SA %s/%08lx got too big "
690 "(len %u, max len %u)\n", __func__,
691 ipsec_address(&saidx->dst, buf, sizeof(buf)),
692 (u_long) ntohl(sav->spi),
693 skip + hlen + rlen + padding + alen, maxpacketsize));
694 ESPSTAT_INC(esps_toobig);
695 error = EMSGSIZE;
696 goto bad;
697 }
698
699 /* Update the counters. */
700 ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip);
701
702 m = m_unshare(m, M_NOWAIT);
703 if (m == NULL) {
704 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__,
705 ipsec_address(&saidx->dst, buf, sizeof(buf)),
706 (u_long) ntohl(sav->spi)));
707 ESPSTAT_INC(esps_hdrops);
708 error = ENOBUFS;
709 goto bad;
710 }
711
712 /* Inject ESP header. */
713 mo = m_makespace(m, skip, hlen, &roff);
714 if (mo == NULL) {
715 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n",
716 __func__, hlen, ipsec_address(&saidx->dst, buf,
717 sizeof(buf)), (u_long) ntohl(sav->spi)));
718 ESPSTAT_INC(esps_hdrops); /* XXX diffs from openbsd */
719 error = ENOBUFS;
720 goto bad;
721 }
722
723 /* Initialize ESP header. */
724 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff,
725 sizeof(uint32_t));
726 SECASVAR_LOCK(sav);
727 if (sav->replay) {
728 uint32_t replay;
729
730 #ifdef REGRESSION
731 /* Emulate replay attack when ipsec_replay is TRUE. */
732 if (!V_ipsec_replay)
733 #endif
734 sav->replay->count++;
735 replay = htonl(sav->replay->count);
736
737 bcopy((caddr_t) &replay, mtod(mo, caddr_t) + roff +
738 sizeof(uint32_t), sizeof(uint32_t));
739 }
740 cryptoid = sav->tdb_cryptoid;
741 if (SAV_ISCTRORGCM(sav))
742 cntr = sav->cntr++;
743 SECASVAR_UNLOCK(sav);
744
745 /*
746 * Add padding -- better to do it ourselves than use the crypto engine,
747 * although if/when we support compression, we'd have to do that.
748 */
749 pad = (u_char *) m_pad(m, padding + alen);
750 if (pad == NULL) {
751 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__,
752 ipsec_address(&saidx->dst, buf, sizeof(buf)),
753 (u_long) ntohl(sav->spi)));
754 m = NULL; /* NB: free'd by m_pad */
755 error = ENOBUFS;
756 goto bad;
757 }
758
759 /*
760 * Add padding: random, zero, or self-describing.
761 * XXX catch unexpected setting
762 */
763 switch (sav->flags & SADB_X_EXT_PMASK) {
764 case SADB_X_EXT_PRAND:
765 (void) read_random(pad, padding - 2);
766 break;
767 case SADB_X_EXT_PZERO:
768 bzero(pad, padding - 2);
769 break;
770 case SADB_X_EXT_PSEQ:
771 for (i = 0; i < padding - 2; i++)
772 pad[i] = i+1;
773 break;
774 }
775
776 /* Fix padding length and Next Protocol in padding itself. */
777 pad[padding - 2] = padding - 2;
778 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1);
779
780 /* Fix Next Protocol in IPv4/IPv6 header. */
781 prot = IPPROTO_ESP;
782 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot);
783
784 /* Get crypto descriptors. */
785 crp = crypto_getreq(esph != NULL ? 2 : 1);
786 if (crp == NULL) {
787 DPRINTF(("%s: failed to acquire crypto descriptors\n",
788 __func__));
789 ESPSTAT_INC(esps_crypto);
790 error = ENOBUFS;
791 goto bad;
792 }
793
794 /* IPsec-specific opaque crypto info. */
795 xd = malloc(sizeof(struct xform_data), M_XDATA, M_NOWAIT | M_ZERO);
796 if (xd == NULL) {
797 crypto_freereq(crp);
798 DPRINTF(("%s: failed to allocate xform_data\n", __func__));
799 ESPSTAT_INC(esps_crypto);
800 error = ENOBUFS;
801 goto bad;
802 }
803
804 crde = crp->crp_desc;
805 crda = crde->crd_next;
806
807 /* Encryption descriptor. */
808 crde->crd_skip = skip + hlen;
809 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
810 crde->crd_flags = CRD_F_ENCRYPT;
811 crde->crd_inject = skip + hlen - sav->ivlen;
812
813 /* Encryption operation. */
814 crde->crd_alg = espx->type;
815 if (SAV_ISCTRORGCM(sav)) {
816 ivp = &crde->crd_iv[0];
817
818 /* GCM IV Format: RFC4106 4 */
819 /* CTR IV Format: RFC3686 4 */
820 /* Salt is last four bytes of key, RFC4106 8.1 */
821 /* Nonce is last four bytes of key, RFC3686 5.1 */
822 memcpy(ivp, sav->key_enc->key_data +
823 _KEYLEN(sav->key_enc) - 4, 4);
824 be64enc(&ivp[4], cntr);
825 if (SAV_ISCTR(sav)) {
826 /* Initial block counter is 1, RFC3686 4 */
827 /* XXXAE: should we use this only for first packet? */
828 be32enc(&ivp[sav->ivlen + 4], 1);
829 }
830
831 m_copyback(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]);
832 crde->crd_flags |= CRD_F_IV_EXPLICIT|CRD_F_IV_PRESENT;
833 }
834
835 /* Callback parameters */
836 xd->sp = sp;
837 xd->sav = sav;
838 xd->idx = idx;
839 xd->cryptoid = cryptoid;
840
841 /* Crypto operation descriptor. */
842 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
843 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
844 crp->crp_buf = (caddr_t) m;
845 crp->crp_callback = esp_output_cb;
846 crp->crp_opaque = (caddr_t) xd;
847 crp->crp_sid = cryptoid;
848
849 if (esph) {
850 /* Authentication descriptor. */
851 crda->crd_alg = esph->type;
852 crda->crd_skip = skip;
853 if (SAV_ISGCM(sav))
854 crda->crd_len = 8; /* RFC4106 5, SPI + SN */
855 else
856 crda->crd_len = m->m_pkthdr.len - (skip + alen);
857 crda->crd_inject = m->m_pkthdr.len - alen;
858 }
859
860 return crypto_dispatch(crp);
861 bad:
862 if (m)
863 m_freem(m);
864 key_freesav(&sav);
865 key_freesp(&sp);
866 return (error);
867 }
868 /*
869 * ESP output callback from the crypto driver.
870 */
871 static int
872 esp_output_cb(struct cryptop *crp)
873 {
874 struct xform_data *xd;
875 struct secpolicy *sp;
876 struct secasvar *sav;
877 struct mbuf *m;
878 uint64_t cryptoid;
879 u_int idx;
880 int error;
881
882 xd = (struct xform_data *) crp->crp_opaque;
883 m = (struct mbuf *) crp->crp_buf;
884 sp = xd->sp;
885 sav = xd->sav;
886 idx = xd->idx;
887 cryptoid = xd->cryptoid;
888
889 /* Check for crypto errors. */
890 if (crp->crp_etype) {
891 if (crp->crp_etype == EAGAIN) {
892 /* Reset the session ID */
893 if (ipsec_updateid(sav, &crp->crp_sid, &cryptoid) != 0)
894 crypto_freesession(cryptoid);
895 xd->cryptoid = crp->crp_sid;
896 return (crypto_dispatch(crp));
897 }
898 ESPSTAT_INC(esps_noxform);
899 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
900 error = crp->crp_etype;
901 m_freem(m);
902 goto bad;
903 }
904
905 /* Shouldn't happen... */
906 if (m == NULL) {
907 ESPSTAT_INC(esps_crypto);
908 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
909 error = EINVAL;
910 goto bad;
911 }
912 free(xd, M_XDATA);
913 crypto_freereq(crp);
914 ESPSTAT_INC(esps_hist[sav->alg_enc]);
915 if (sav->tdb_authalgxform != NULL)
916 AHSTAT_INC(ahs_hist[sav->alg_auth]);
917
918 #ifdef REGRESSION
919 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
920 if (V_ipsec_integrity) {
921 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN];
922 const struct auth_hash *esph;
923
924 /*
925 * Corrupt HMAC if we want to test integrity verification of
926 * the other side.
927 */
928 esph = sav->tdb_authalgxform;
929 if (esph != NULL) {
930 int alen;
931
932 alen = xform_ah_authsize(esph);
933 m_copyback(m, m->m_pkthdr.len - alen,
934 alen, ipseczeroes);
935 }
936 }
937 #endif
938
939 /* NB: m is reclaimed by ipsec_process_done. */
940 error = ipsec_process_done(m, sp, sav, idx);
941 return (error);
942 bad:
943 free(xd, M_XDATA);
944 crypto_freereq(crp);
945 key_freesav(&sav);
946 key_freesp(&sp);
947 return (error);
948 }
949
950 static struct xformsw esp_xformsw = {
951 .xf_type = XF_ESP,
952 .xf_name = "IPsec ESP",
953 .xf_init = esp_init,
954 .xf_zeroize = esp_zeroize,
955 .xf_input = esp_input,
956 .xf_output = esp_output,
957 };
958
959 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
960 xform_attach, &esp_xformsw);
961 SYSUNINIT(esp_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
962 xform_detach, &esp_xformsw);
Cache object: a69c966b670c4439fd5f6564bd5d0825
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