1 /* $NetBSD: xform_esp.c,v 1.12 2006/11/16 01:33:49 christos 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 1.12 2006/11/16 01:33:49 christos Exp $");
43
44 #include "opt_inet.h"
45 #ifdef __FreeBSD__
46 #include "opt_inet6.h"
47 #endif
48
49 #include <sys/param.h>
50 #include <sys/systm.h>
51 #include <sys/mbuf.h>
52 #include <sys/socket.h>
53 #include <sys/syslog.h>
54 #include <sys/kernel.h>
55 /*#include <sys/random.h>*/
56 #include <sys/sysctl.h>
57
58 #include <net/if.h>
59
60 #include <netinet/in.h>
61 #include <netinet/in_systm.h>
62 #include <netinet/ip.h>
63 #include <netinet/ip_ecn.h>
64 #include <netinet/ip6.h>
65
66 #include <net/route.h>
67 #include <netipsec/ipsec.h>
68 #include <netipsec/ah.h>
69 #include <netipsec/ah_var.h>
70 #include <netipsec/esp.h>
71 #include <netipsec/esp_var.h>
72 #include <netipsec/xform.h>
73
74 #ifdef INET6
75 #include <netinet6/ip6_var.h>
76 #include <netipsec/ipsec6.h>
77 # ifdef __FreeBSD__
78 # include <netinet6/ip6_ecn.h>
79 # endif
80 #endif
81
82 #include <netipsec/key.h>
83 #include <netipsec/key_debug.h>
84
85 #include <netipsec/ipsec_osdep.h>
86
87 #include <opencrypto/cryptodev.h>
88 #include <opencrypto/xform.h>
89
90 int esp_enable = 1;
91 struct espstat espstat;
92
93 #ifdef __FreeBSD__
94 SYSCTL_DECL(_net_inet_esp);
95 SYSCTL_INT(_net_inet_esp, OID_AUTO,
96 esp_enable, CTLFLAG_RW, &esp_enable, 0, "");
97 SYSCTL_STRUCT(_net_inet_esp, IPSECCTL_STATS,
98 stats, CTLFLAG_RD, &espstat, espstat, "");
99 #endif /* __FreeBSD__ */
100
101 static int esp_max_ivlen; /* max iv length over all algorithms */
102
103 static int esp_input_cb(struct cryptop *op);
104 static int esp_output_cb(struct cryptop *crp);
105
106 /*
107 * NB: this is public for use by the PF_KEY support.
108 * NB: if you add support here; be sure to add code to esp_attach below!
109 */
110 struct enc_xform *
111 esp_algorithm_lookup(int alg)
112 {
113 if (alg >= ESP_ALG_MAX)
114 return NULL;
115 switch (alg) {
116 case SADB_EALG_DESCBC:
117 return &enc_xform_des;
118 case SADB_EALG_3DESCBC:
119 return &enc_xform_3des;
120 case SADB_X_EALG_AES:
121 return &enc_xform_rijndael128;
122 case SADB_X_EALG_BLOWFISHCBC:
123 return &enc_xform_blf;
124 case SADB_X_EALG_CAST128CBC:
125 return &enc_xform_cast5;
126 case SADB_X_EALG_SKIPJACK:
127 return &enc_xform_skipjack;
128 case SADB_EALG_NULL:
129 return &enc_xform_null;
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 ("esp_hdrsiz: 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) + esp_max_ivlen + 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(("esp_init: unsupported encryption algorithm %d\n",
179 sav->alg_enc));
180 return EINVAL;
181 }
182 if (sav->key_enc == NULL) {
183 DPRINTF(("esp_init: no encoding key for %s algorithm\n",
184 txform->name));
185 return EINVAL;
186 }
187 if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) {
188 DPRINTF(("esp_init: 4-byte IV not supported with protocol\n"));
189 return EINVAL;
190 }
191 keylen = _KEYLEN(sav->key_enc);
192 if (txform->minkey > keylen || keylen > txform->maxkey) {
193 DPRINTF(("esp_init: invalid key length %u, must be in "
194 "the range [%u..%u] for algorithm %s\n",
195 keylen, txform->minkey, txform->maxkey,
196 txform->name));
197 return EINVAL;
198 }
199
200 /*
201 * NB: The null xform needs a non-zero blocksize to keep the
202 * crypto code happy but if we use it to set ivlen then
203 * the ESP header will be processed incorrectly. The
204 * compromise is to force it to zero here.
205 */
206 sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize);
207 sav->iv = (caddr_t) malloc(sav->ivlen, M_SECA, M_WAITOK);
208 if (sav->iv == NULL) {
209 DPRINTF(("esp_init: no memory for IV\n"));
210 return EINVAL;
211 }
212 key_randomfill(sav->iv, sav->ivlen); /*XXX*/
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 /* Initialize crypto session. */
228 bzero(&crie, sizeof (crie));
229 crie.cri_alg = sav->tdb_encalgxform->type;
230 crie.cri_klen = _KEYBITS(sav->key_enc);
231 crie.cri_key = _KEYBUF(sav->key_enc);
232 /* XXX Rounds ? */
233
234 if (sav->tdb_authalgxform && sav->tdb_encalgxform) {
235 /* init both auth & enc */
236 crie.cri_next = &cria;
237 error = crypto_newsession(&sav->tdb_cryptoid,
238 &crie, crypto_support);
239 } else if (sav->tdb_encalgxform) {
240 error = crypto_newsession(&sav->tdb_cryptoid,
241 &crie, crypto_support);
242 } else if (sav->tdb_authalgxform) {
243 error = crypto_newsession(&sav->tdb_cryptoid,
244 &cria, crypto_support);
245 } else {
246 /* XXX cannot happen? */
247 DPRINTF(("esp_init: no encoding OR authentication xform!\n"));
248 error = EINVAL;
249 }
250 return error;
251 }
252
253 /*
254 * Paranoia.
255 */
256 static int
257 esp_zeroize(struct secasvar *sav)
258 {
259 /* NB: ah_zerorize free's the crypto session state */
260 int error = ah_zeroize(sav);
261
262 if (sav->key_enc)
263 bzero(_KEYBUF(sav->key_enc), _KEYLEN(sav->key_enc));
264 /* NB: sav->iv is freed elsewhere, even though we malloc it! */
265 sav->tdb_encalgxform = NULL;
266 sav->tdb_xform = NULL;
267 return error;
268 }
269
270 /*
271 * ESP input processing, called (eventually) through the protocol switch.
272 */
273 static int
274 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
275 {
276 struct auth_hash *esph;
277 struct enc_xform *espx;
278 struct tdb_ident *tdbi;
279 struct tdb_crypto *tc;
280 int plen, alen, hlen;
281 struct m_tag *mtag;
282 struct newesp *esp;
283
284 struct cryptodesc *crde;
285 struct cryptop *crp;
286
287 IPSEC_SPLASSERT_SOFTNET("esp_input");
288
289 IPSEC_ASSERT(sav != NULL, ("esp_input: null SA"));
290 IPSEC_ASSERT(sav->tdb_encalgxform != NULL,
291 ("esp_input: null encoding xform"));
292 IPSEC_ASSERT((skip&3) == 0 && (m->m_pkthdr.len&3) == 0,
293 ("esp_input: misaligned packet, skip %u pkt len %u",
294 skip, m->m_pkthdr.len));
295
296 /* XXX don't pullup, just copy header */
297 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp));
298
299 esph = sav->tdb_authalgxform;
300 espx = sav->tdb_encalgxform;
301
302 /* Determine the ESP header length */
303 if (sav->flags & SADB_X_EXT_OLD)
304 hlen = sizeof (struct esp) + sav->ivlen;
305 else
306 hlen = sizeof (struct newesp) + sav->ivlen;
307 /* Authenticator hash size */
308 alen = esph ? AH_HMAC_HASHLEN : 0;
309
310 /*
311 * Verify payload length is multiple of encryption algorithm
312 * block size.
313 *
314 * NB: This works for the null algorithm because the blocksize
315 * is 4 and all packets must be 4-byte aligned regardless
316 * of the algorithm.
317 */
318 plen = m->m_pkthdr.len - (skip + hlen + alen);
319 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) {
320 DPRINTF(("esp_input: "
321 "payload of %d octets not a multiple of %d octets,"
322 " SA %s/%08lx\n",
323 plen, espx->blocksize,
324 ipsec_address(&sav->sah->saidx.dst),
325 (u_long) ntohl(sav->spi)));
326 espstat.esps_badilen++;
327 m_freem(m);
328 return EINVAL;
329 }
330
331 /*
332 * Check sequence number.
333 */
334 if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) {
335 DPRINTF(("esp_input: packet replay check for %s\n",
336 ipsec_logsastr(sav))); /*XXX*/
337 espstat.esps_replay++;
338 m_freem(m);
339 return ENOBUFS; /*XXX*/
340 }
341
342 /* Update the counters */
343 espstat.esps_ibytes += m->m_pkthdr.len - skip - hlen - alen;
344
345 /* Find out if we've already done crypto */
346 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL);
347 mtag != NULL;
348 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) {
349 tdbi = (struct tdb_ident *) (mtag + 1);
350 if (tdbi->proto == sav->sah->saidx.proto &&
351 tdbi->spi == sav->spi &&
352 !bcmp(&tdbi->dst, &sav->sah->saidx.dst,
353 sizeof(union sockaddr_union)))
354 break;
355 }
356
357 /* Get crypto descriptors */
358 crp = crypto_getreq(esph && espx ? 2 : 1);
359 if (crp == NULL) {
360 DPRINTF(("esp_input: failed to acquire crypto descriptors\n"));
361 espstat.esps_crypto++;
362 m_freem(m);
363 return ENOBUFS;
364 }
365
366 /* Get IPsec-specific opaque pointer */
367 if (esph == NULL || mtag != NULL)
368 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
369 M_XDATA, M_NOWAIT|M_ZERO);
370 else
371 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen,
372 M_XDATA, M_NOWAIT|M_ZERO);
373 if (tc == NULL) {
374 crypto_freereq(crp);
375 DPRINTF(("esp_input: failed to allocate tdb_crypto\n"));
376 espstat.esps_crypto++;
377 m_freem(m);
378 return ENOBUFS;
379 }
380
381 tc->tc_ptr = (caddr_t) mtag;
382
383 if (esph) {
384 struct cryptodesc *crda = crp->crp_desc;
385
386 IPSEC_ASSERT(crda != NULL, ("esp_input: null ah crypto descriptor"));
387
388 /* Authentication descriptor */
389 crda->crd_skip = skip;
390 crda->crd_len = m->m_pkthdr.len - (skip + alen);
391 crda->crd_inject = m->m_pkthdr.len - alen;
392
393 crda->crd_alg = esph->type;
394 crda->crd_key = _KEYBUF(sav->key_auth);
395 crda->crd_klen = _KEYBITS(sav->key_auth);
396
397 /* Copy the authenticator */
398 if (mtag == NULL)
399 m_copydata(m, m->m_pkthdr.len - alen, alen,
400 (caddr_t) (tc + 1));
401
402 /* Chain authentication request */
403 crde = crda->crd_next;
404 } else {
405 crde = crp->crp_desc;
406 }
407
408 /* Crypto operation descriptor */
409 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */
410 crp->crp_flags = CRYPTO_F_IMBUF;
411 crp->crp_buf = (caddr_t) m;
412 crp->crp_callback = esp_input_cb;
413 crp->crp_sid = sav->tdb_cryptoid;
414 crp->crp_opaque = (caddr_t) tc;
415
416 /* These are passed as-is to the callback */
417 tc->tc_spi = sav->spi;
418 tc->tc_dst = sav->sah->saidx.dst;
419 tc->tc_proto = sav->sah->saidx.proto;
420 tc->tc_protoff = protoff;
421 tc->tc_skip = skip;
422
423 /* Decryption descriptor */
424 if (espx) {
425 IPSEC_ASSERT(crde != NULL, ("esp_input: null esp crypto descriptor"));
426 crde->crd_skip = skip + hlen;
427 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
428 crde->crd_inject = skip + hlen - sav->ivlen;
429
430 crde->crd_alg = espx->type;
431 crde->crd_key = _KEYBUF(sav->key_enc);
432 crde->crd_klen = _KEYBITS(sav->key_enc);
433 /* XXX Rounds ? */
434 }
435
436 if (mtag == NULL)
437 return crypto_dispatch(crp);
438 else
439 return esp_input_cb(crp);
440 }
441
442 #ifdef INET6
443 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \
444 if (saidx->dst.sa.sa_family == AF_INET6) { \
445 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \
446 } else { \
447 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \
448 } \
449 } while (0)
450 #else
451 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \
452 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag))
453 #endif
454
455 /*
456 * ESP input callback from the crypto driver.
457 */
458 static int
459 esp_input_cb(struct cryptop *crp)
460 {
461 u_int8_t lastthree[3], aalg[AH_HMAC_HASHLEN];
462 int s, hlen, skip, protoff, error;
463 struct mbuf *m;
464 struct cryptodesc *crd;
465 struct auth_hash *esph;
466 struct enc_xform *espx;
467 struct tdb_crypto *tc;
468 struct m_tag *mtag;
469 struct secasvar *sav;
470 struct secasindex *saidx;
471 caddr_t ptr;
472
473 crd = crp->crp_desc;
474 IPSEC_ASSERT(crd != NULL, ("esp_input_cb: null crypto descriptor!"));
475
476 tc = (struct tdb_crypto *) crp->crp_opaque;
477 IPSEC_ASSERT(tc != NULL, ("esp_input_cb: null opaque crypto data area!"));
478 skip = tc->tc_skip;
479 protoff = tc->tc_protoff;
480 mtag = (struct m_tag *) tc->tc_ptr;
481 m = (struct mbuf *) crp->crp_buf;
482
483 s = splsoftnet();
484
485 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi);
486 if (sav == NULL) {
487 espstat.esps_notdb++;
488 DPRINTF(("esp_input_cb: SA expired while in crypto "
489 "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst),
490 (u_long) ntohl(tc->tc_spi), tc->tc_proto));
491 error = ENOBUFS; /*XXX*/
492 goto bad;
493 }
494
495 saidx = &sav->sah->saidx;
496 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
497 saidx->dst.sa.sa_family == AF_INET6,
498 ("ah_input_cb: unexpected protocol family %u",
499 saidx->dst.sa.sa_family));
500
501 esph = sav->tdb_authalgxform;
502 espx = sav->tdb_encalgxform;
503
504 /* Check for crypto errors */
505 if (crp->crp_etype) {
506 /* Reset the session ID */
507 if (sav->tdb_cryptoid != 0)
508 sav->tdb_cryptoid = crp->crp_sid;
509
510 if (crp->crp_etype == EAGAIN) {
511 KEY_FREESAV(&sav);
512 splx(s);
513 return crypto_dispatch(crp);
514 }
515
516 espstat.esps_noxform++;
517 DPRINTF(("esp_input_cb: crypto error %d\n", crp->crp_etype));
518 error = crp->crp_etype;
519 goto bad;
520 }
521
522 /* Shouldn't happen... */
523 if (m == NULL) {
524 espstat.esps_crypto++;
525 DPRINTF(("esp_input_cb: bogus returned buffer from crypto\n"));
526 error = EINVAL;
527 goto bad;
528 }
529 espstat.esps_hist[sav->alg_enc]++;
530
531 /* If authentication was performed, check now. */
532 if (esph != NULL) {
533 /*
534 * If we have a tag, it means an IPsec-aware NIC did
535 * the verification for us. Otherwise we need to
536 * check the authentication calculation.
537 */
538 ahstat.ahs_hist[sav->alg_auth]++;
539 if (mtag == NULL) {
540 /* Copy the authenticator from the packet */
541 m_copydata(m, m->m_pkthdr.len - esph->authsize,
542 esph->authsize, aalg);
543
544 ptr = (caddr_t) (tc + 1);
545
546 /* Verify authenticator */
547 if (bcmp(ptr, aalg, esph->authsize) != 0) {
548 DPRINTF(("esp_input_cb: "
549 "authentication hash mismatch for packet in SA %s/%08lx\n",
550 ipsec_address(&saidx->dst),
551 (u_long) ntohl(sav->spi)));
552 espstat.esps_badauth++;
553 error = EACCES;
554 goto bad;
555 }
556 }
557
558 /* Remove trailing authenticator */
559 m_adj(m, -(esph->authsize));
560 }
561
562 /* Release the crypto descriptors */
563 free(tc, M_XDATA), tc = NULL;
564 crypto_freereq(crp), crp = NULL;
565
566 /*
567 * Packet is now decrypted.
568 */
569 m->m_flags |= M_DECRYPTED;
570
571 /*
572 * Update replay sequence number, if appropriate.
573 */
574 if (sav->replay) {
575 u_int32_t seq;
576
577 m_copydata(m, skip + offsetof(struct newesp, esp_seq),
578 sizeof (seq), (caddr_t) &seq);
579 if (ipsec_updatereplay(ntohl(seq), sav)) {
580 DPRINTF(("%s: packet replay check for %s\n", __func__,
581 ipsec_logsastr(sav)));
582 espstat.esps_replay++;
583 error = ENOBUFS;
584 goto bad;
585 }
586 }
587
588 /* Determine the ESP header length */
589 if (sav->flags & SADB_X_EXT_OLD)
590 hlen = sizeof (struct esp) + sav->ivlen;
591 else
592 hlen = sizeof (struct newesp) + sav->ivlen;
593
594 /* Remove the ESP header and IV from the mbuf. */
595 error = m_striphdr(m, skip, hlen);
596 if (error) {
597 espstat.esps_hdrops++;
598 DPRINTF(("esp_input_cb: bad mbuf chain, SA %s/%08lx\n",
599 ipsec_address(&sav->sah->saidx.dst),
600 (u_long) ntohl(sav->spi)));
601 goto bad;
602 }
603
604 /* Save the last three bytes of decrypted data */
605 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree);
606
607 /* Verify pad length */
608 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) {
609 espstat.esps_badilen++;
610 DPRINTF(("esp_input_cb: invalid padding length %d "
611 "for %u byte packet in SA %s/%08lx\n",
612 lastthree[1], m->m_pkthdr.len - skip,
613 ipsec_address(&sav->sah->saidx.dst),
614 (u_long) ntohl(sav->spi)));
615 error = EINVAL;
616 goto bad;
617 }
618
619 /* Verify correct decryption by checking the last padding bytes */
620 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) {
621 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) {
622 espstat.esps_badenc++;
623 DPRINTF(("esp_input_cb: decryption failed "
624 "for packet in SA %s/%08lx\n",
625 ipsec_address(&sav->sah->saidx.dst),
626 (u_long) ntohl(sav->spi)));
627 DPRINTF(("esp_input_cb: %x %x\n", lastthree[0], lastthree[1]));
628 error = EINVAL;
629 goto bad;
630 }
631 }
632
633 /* Trim the mbuf chain to remove trailing authenticator and padding */
634 m_adj(m, -(lastthree[1] + 2));
635
636 /* Restore the Next Protocol field */
637 m = m_copyback_cow(m, protoff, sizeof (u_int8_t), lastthree + 2,
638 M_DONTWAIT);
639
640 if (m == NULL) {
641 espstat.esps_crypto++;
642 DPRINTF(("esp_input_cb: failed to allocate mbuf\n"));
643 error = ENOBUFS;
644 goto bad;
645 }
646
647 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag);
648
649 KEY_FREESAV(&sav);
650 splx(s);
651 return error;
652 bad:
653 if (sav)
654 KEY_FREESAV(&sav);
655 splx(s);
656 if (m != NULL)
657 m_freem(m);
658 if (tc != NULL)
659 free(tc, M_XDATA);
660 if (crp != NULL)
661 crypto_freereq(crp);
662 return error;
663 }
664
665 /*
666 * ESP output routine, called by ipsec[46]_process_packet().
667 */
668 static int
669 esp_output(
670 struct mbuf *m,
671 struct ipsecrequest *isr,
672 struct mbuf **mp,
673 int skip,
674 int protoff
675 )
676 {
677 struct enc_xform *espx;
678 struct auth_hash *esph;
679 int hlen, rlen, plen, padding, blks, alen, i, roff;
680 struct mbuf *mo = (struct mbuf *) NULL;
681 struct tdb_crypto *tc;
682 struct secasvar *sav;
683 struct secasindex *saidx;
684 unsigned char *pad;
685 u_int8_t prot;
686 int error, maxpacketsize;
687
688 struct cryptodesc *crde = NULL, *crda = NULL;
689 struct cryptop *crp;
690
691 IPSEC_SPLASSERT_SOFTNET("esp_output");
692
693 sav = isr->sav;
694 IPSEC_ASSERT(sav != NULL, ("esp_output: null SA"));
695 esph = sav->tdb_authalgxform;
696 espx = sav->tdb_encalgxform;
697 IPSEC_ASSERT(espx != NULL, ("esp_output: null encoding xform"));
698
699 if (sav->flags & SADB_X_EXT_OLD)
700 hlen = sizeof (struct esp) + sav->ivlen;
701 else
702 hlen = sizeof (struct newesp) + sav->ivlen;
703
704 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */
705 /*
706 * NB: The null encoding transform has a blocksize of 4
707 * so that headers are properly aligned.
708 */
709 blks = espx->blocksize; /* IV blocksize */
710
711 /* XXX clamp padding length a la KAME??? */
712 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;
713 plen = rlen + padding; /* Padded payload length. */
714
715 if (esph)
716 alen = AH_HMAC_HASHLEN;
717 else
718 alen = 0;
719
720 espstat.esps_output++;
721
722 saidx = &sav->sah->saidx;
723 /* Check for maximum packet size violations. */
724 switch (saidx->dst.sa.sa_family) {
725 #ifdef INET
726 case AF_INET:
727 maxpacketsize = IP_MAXPACKET;
728 break;
729 #endif /* INET */
730 #ifdef INET6
731 case AF_INET6:
732 maxpacketsize = IPV6_MAXPACKET;
733 break;
734 #endif /* INET6 */
735 default:
736 DPRINTF(("esp_output: unknown/unsupported protocol "
737 "family %d, SA %s/%08lx\n",
738 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst),
739 (u_long) ntohl(sav->spi)));
740 espstat.esps_nopf++;
741 error = EPFNOSUPPORT;
742 goto bad;
743 }
744 if (skip + hlen + rlen + padding + alen > maxpacketsize) {
745 DPRINTF(("esp_output: packet in SA %s/%08lx got too big "
746 "(len %u, max len %u)\n",
747 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi),
748 skip + hlen + rlen + padding + alen, maxpacketsize));
749 espstat.esps_toobig++;
750 error = EMSGSIZE;
751 goto bad;
752 }
753
754 /* Update the counters. */
755 espstat.esps_obytes += m->m_pkthdr.len - skip;
756
757 m = m_clone(m);
758 if (m == NULL) {
759 DPRINTF(("esp_output: cannot clone mbuf chain, SA %s/%08lx\n",
760 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
761 espstat.esps_hdrops++;
762 error = ENOBUFS;
763 goto bad;
764 }
765
766 /* Inject ESP header. */
767 mo = m_makespace(m, skip, hlen, &roff);
768 if (mo == NULL) {
769 DPRINTF(("esp_output: failed to inject %u byte ESP hdr for SA "
770 "%s/%08lx\n",
771 hlen, ipsec_address(&saidx->dst),
772 (u_long) ntohl(sav->spi)));
773 espstat.esps_hdrops++; /* XXX diffs from openbsd */
774 error = ENOBUFS;
775 goto bad;
776 }
777
778 /* Initialize ESP header. */
779 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t));
780 if (sav->replay) {
781 u_int32_t replay;
782
783 #ifdef IPSEC_DEBUG
784 /* Emulate replay attack when ipsec_replay is TRUE. */
785 if (!ipsec_replay)
786 #endif
787 sav->replay->count++;
788
789 replay = htonl(sav->replay->count);
790 bcopy((caddr_t) &replay,
791 mtod(mo, caddr_t) + roff + sizeof(u_int32_t),
792 sizeof(u_int32_t));
793 }
794
795 /*
796 * Add padding -- better to do it ourselves than use the crypto engine,
797 * although if/when we support compression, we'd have to do that.
798 */
799 pad = (u_char *) m_pad(m, padding + alen);
800 if (pad == NULL) {
801 DPRINTF(("esp_output: m_pad failed for SA %s/%08lx\n",
802 ipsec_address(&saidx->dst), (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 (void) read_random(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 && espx ? 2 : 1);
835 if (crp == NULL) {
836 DPRINTF(("esp_output: failed to acquire crypto descriptors\n"));
837 espstat.esps_crypto++;
838 error = ENOBUFS;
839 goto bad;
840 }
841
842 if (espx) {
843 crde = crp->crp_desc;
844 crda = crde->crd_next;
845
846 /* Encryption descriptor. */
847 crde->crd_skip = skip + hlen;
848 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
849 crde->crd_flags = CRD_F_ENCRYPT;
850 crde->crd_inject = skip + hlen - sav->ivlen;
851
852 /* Encryption operation. */
853 crde->crd_alg = espx->type;
854 crde->crd_key = _KEYBUF(sav->key_enc);
855 crde->crd_klen = _KEYBITS(sav->key_enc);
856 /* XXX Rounds ? */
857 } else
858 crda = crp->crp_desc;
859
860 /* IPsec-specific opaque crypto info. */
861 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
862 M_XDATA, M_NOWAIT|M_ZERO);
863 if (tc == NULL) {
864 crypto_freereq(crp);
865 DPRINTF(("esp_output: failed to allocate tdb_crypto\n"));
866 espstat.esps_crypto++;
867 error = ENOBUFS;
868 goto bad;
869 }
870
871 /* Callback parameters */
872 tc->tc_isr = isr;
873 tc->tc_spi = sav->spi;
874 tc->tc_dst = saidx->dst;
875 tc->tc_proto = saidx->proto;
876
877 /* Crypto operation descriptor. */
878 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
879 crp->crp_flags = CRYPTO_F_IMBUF;
880 crp->crp_buf = (caddr_t) m;
881 crp->crp_callback = esp_output_cb;
882 crp->crp_opaque = (caddr_t) tc;
883 crp->crp_sid = sav->tdb_cryptoid;
884
885 if (esph) {
886 /* Authentication descriptor. */
887 crda->crd_skip = skip;
888 crda->crd_len = m->m_pkthdr.len - (skip + alen);
889 crda->crd_inject = m->m_pkthdr.len - alen;
890
891 /* Authentication operation. */
892 crda->crd_alg = esph->type;
893 crda->crd_key = _KEYBUF(sav->key_auth);
894 crda->crd_klen = _KEYBITS(sav->key_auth);
895 }
896
897 return crypto_dispatch(crp);
898 bad:
899 if (m)
900 m_freem(m);
901 return (error);
902 }
903
904 /*
905 * ESP output callback from the crypto driver.
906 */
907 static int
908 esp_output_cb(struct cryptop *crp)
909 {
910 struct tdb_crypto *tc;
911 struct ipsecrequest *isr;
912 struct secasvar *sav;
913 struct mbuf *m;
914 int s, err, error;
915
916 tc = (struct tdb_crypto *) crp->crp_opaque;
917 IPSEC_ASSERT(tc != NULL, ("esp_output_cb: null opaque data area!"));
918 m = (struct mbuf *) crp->crp_buf;
919
920 s = splsoftnet();
921
922 isr = tc->tc_isr;
923 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi);
924 if (sav == NULL) {
925 espstat.esps_notdb++;
926 DPRINTF(("esp_output_cb: SA expired while in crypto "
927 "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst),
928 (u_long) ntohl(tc->tc_spi), tc->tc_proto));
929 error = ENOBUFS; /*XXX*/
930 goto bad;
931 }
932 IPSEC_ASSERT(isr->sav == sav,
933 ("esp_output_cb: SA changed was %p now %p\n", isr->sav, sav));
934
935 /* Check for crypto errors. */
936 if (crp->crp_etype) {
937 /* Reset session ID. */
938 if (sav->tdb_cryptoid != 0)
939 sav->tdb_cryptoid = crp->crp_sid;
940
941 if (crp->crp_etype == EAGAIN) {
942 KEY_FREESAV(&sav);
943 splx(s);
944 return crypto_dispatch(crp);
945 }
946
947 espstat.esps_noxform++;
948 DPRINTF(("esp_output_cb: crypto error %d\n", crp->crp_etype));
949 error = crp->crp_etype;
950 goto bad;
951 }
952
953 /* Shouldn't happen... */
954 if (m == NULL) {
955 espstat.esps_crypto++;
956 DPRINTF(("esp_output_cb: bogus returned buffer from crypto\n"));
957 error = EINVAL;
958 goto bad;
959 }
960 espstat.esps_hist[sav->alg_enc]++;
961 if (sav->tdb_authalgxform != NULL)
962 ahstat.ahs_hist[sav->alg_auth]++;
963
964 /* Release crypto descriptors. */
965 free(tc, M_XDATA);
966 crypto_freereq(crp);
967
968 #ifdef IPSEC_DEBUG
969 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
970 if (ipsec_integrity) {
971 static unsigned char ipseczeroes[AH_HMAC_HASHLEN];
972 struct auth_hash *esph;
973
974 /*
975 * Corrupt HMAC if we want to test integrity verification of
976 * the other side.
977 */
978 esph = sav->tdb_authalgxform;
979 if (esph != NULL) {
980 m_copyback(m, m->m_pkthdr.len - AH_HMAC_HASHLEN,
981 AH_HMAC_HASHLEN, ipseczeroes);
982 }
983 }
984 #endif
985
986 /* NB: m is reclaimed by ipsec_process_done. */
987 err = ipsec_process_done(m, isr);
988 KEY_FREESAV(&sav);
989 splx(s);
990 return err;
991 bad:
992 if (sav)
993 KEY_FREESAV(&sav);
994 splx(s);
995 if (m)
996 m_freem(m);
997 free(tc, M_XDATA);
998 crypto_freereq(crp);
999 return error;
1000 }
1001
1002 static struct xformsw esp_xformsw = {
1003 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP",
1004 esp_init, esp_zeroize, esp_input,
1005 esp_output,
1006 NULL,
1007 };
1008
1009 INITFN void
1010 esp_attach(void)
1011 {
1012 #define MAXIV(xform) \
1013 if (xform.blocksize > esp_max_ivlen) \
1014 esp_max_ivlen = xform.blocksize \
1015
1016 esp_max_ivlen = 0;
1017 MAXIV(enc_xform_des); /* SADB_EALG_DESCBC */
1018 MAXIV(enc_xform_3des); /* SADB_EALG_3DESCBC */
1019 MAXIV(enc_xform_rijndael128); /* SADB_X_EALG_AES */
1020 MAXIV(enc_xform_blf); /* SADB_X_EALG_BLOWFISHCBC */
1021 MAXIV(enc_xform_cast5); /* SADB_X_EALG_CAST128CBC */
1022 MAXIV(enc_xform_skipjack); /* SADB_X_EALG_SKIPJACK */
1023 MAXIV(enc_xform_null); /* SADB_EALG_NULL */
1024
1025 xform_register(&esp_xformsw);
1026 #undef MAXIV
1027 }
1028 #ifdef __FreeBSD__
1029 SYSINIT(esp_xform_init, SI_SUB_DRIVERS, SI_ORDER_FIRST, esp_attach, NULL)
1030 #else
1031 #endif
Cache object: f094c494548724142925756b338ba668
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