1 /* $FreeBSD: releng/6.4/sys/netipsec/xform_esp.c 174400 2007-12-07 08:45:29Z gnn $ */
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/random.h>
48 #include <sys/sysctl.h>
49
50 #include <net/if.h>
51
52 #include <netinet/in.h>
53 #include <netinet/in_systm.h>
54 #include <netinet/ip.h>
55 #include <netinet/ip_ecn.h>
56 #include <netinet/ip6.h>
57
58 #include <net/route.h>
59 #include <netipsec/ipsec.h>
60 #include <netipsec/ah.h>
61 #include <netipsec/ah_var.h>
62 #include <netipsec/esp.h>
63 #include <netipsec/esp_var.h>
64 #include <netipsec/xform.h>
65
66 #ifdef INET6
67 #include <netinet6/ip6_var.h>
68 #include <netipsec/ipsec6.h>
69 #include <netinet6/ip6_ecn.h>
70 #endif
71
72 #include <netipsec/key.h>
73 #include <netipsec/key_debug.h>
74
75 #include <opencrypto/cryptodev.h>
76 #include <opencrypto/xform.h>
77
78 int esp_enable = 1;
79 struct espstat espstat;
80
81 SYSCTL_DECL(_net_inet_esp);
82 SYSCTL_INT(_net_inet_esp, OID_AUTO,
83 esp_enable, CTLFLAG_RW, &esp_enable, 0, "");
84 SYSCTL_STRUCT(_net_inet_esp, IPSECCTL_STATS,
85 stats, CTLFLAG_RD, &espstat, espstat, "");
86
87 static int esp_max_ivlen; /* max iv length over all algorithms */
88
89 static int esp_input_cb(struct cryptop *op);
90 static int esp_output_cb(struct cryptop *crp);
91
92 /*
93 * NB: this is public for use by the PF_KEY support.
94 * NB: if you add support here; be sure to add code to esp_attach below!
95 */
96 struct enc_xform *
97 esp_algorithm_lookup(int alg)
98 {
99 if (alg >= ESP_ALG_MAX)
100 return NULL;
101 switch (alg) {
102 case SADB_EALG_DESCBC:
103 return &enc_xform_des;
104 case SADB_EALG_3DESCBC:
105 return &enc_xform_3des;
106 case SADB_X_EALG_AES:
107 return &enc_xform_rijndael128;
108 case SADB_X_EALG_BLOWFISHCBC:
109 return &enc_xform_blf;
110 case SADB_X_EALG_CAST128CBC:
111 return &enc_xform_cast5;
112 case SADB_X_EALG_SKIPJACK:
113 return &enc_xform_skipjack;
114 case SADB_EALG_NULL:
115 return &enc_xform_null;
116 case SADB_X_EALG_CAMELLIACBC:
117 return &enc_xform_camellia;
118 }
119 return NULL;
120 }
121
122 size_t
123 esp_hdrsiz(struct secasvar *sav)
124 {
125 size_t size;
126
127 if (sav != NULL) {
128 /*XXX not right for null algorithm--does it matter??*/
129 IPSEC_ASSERT(sav->tdb_encalgxform != NULL,
130 ("SA with null xform"));
131 if (sav->flags & SADB_X_EXT_OLD)
132 size = sizeof (struct esp);
133 else
134 size = sizeof (struct newesp);
135 size += sav->tdb_encalgxform->blocksize + 9;
136 /*XXX need alg check???*/
137 if (sav->tdb_authalgxform != NULL && sav->replay)
138 size += ah_hdrsiz(sav);
139 } else {
140 /*
141 * base header size
142 * + max iv length for CBC mode
143 * + max pad length
144 * + sizeof (pad length field)
145 * + sizeof (next header field)
146 * + max icv supported.
147 */
148 size = sizeof (struct newesp) + esp_max_ivlen + 9 + 16;
149 }
150 return size;
151 }
152
153 /*
154 * esp_init() is called when an SPI is being set up.
155 */
156 static int
157 esp_init(struct secasvar *sav, struct xformsw *xsp)
158 {
159 struct enc_xform *txform;
160 struct cryptoini cria, crie;
161 int keylen;
162 int error;
163
164 txform = esp_algorithm_lookup(sav->alg_enc);
165 if (txform == NULL) {
166 DPRINTF(("%s: unsupported encryption algorithm %d\n",
167 __func__, sav->alg_enc));
168 return EINVAL;
169 }
170 if (sav->key_enc == NULL) {
171 DPRINTF(("%s: no encoding key for %s algorithm\n",
172 __func__, txform->name));
173 return EINVAL;
174 }
175 if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) {
176 DPRINTF(("%s: 4-byte IV not supported with protocol\n",
177 __func__));
178 return EINVAL;
179 }
180 keylen = _KEYLEN(sav->key_enc);
181 if (txform->minkey > keylen || keylen > txform->maxkey) {
182 DPRINTF(("%s: invalid key length %u, must be in the range "
183 "[%u..%u] for algorithm %s\n", __func__,
184 keylen, txform->minkey, txform->maxkey,
185 txform->name));
186 return EINVAL;
187 }
188
189 /*
190 * NB: The null xform needs a non-zero blocksize to keep the
191 * crypto code happy but if we use it to set ivlen then
192 * the ESP header will be processed incorrectly. The
193 * compromise is to force it to zero here.
194 */
195 sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize);
196 sav->iv = (caddr_t) malloc(sav->ivlen, M_XDATA, M_WAITOK);
197 if (sav->iv == NULL) {
198 DPRINTF(("%s: no memory for IV\n", __func__));
199 return EINVAL;
200 }
201 key_randomfill(sav->iv, sav->ivlen); /*XXX*/
202
203 /*
204 * Setup AH-related state.
205 */
206 if (sav->alg_auth != 0) {
207 error = ah_init0(sav, xsp, &cria);
208 if (error)
209 return error;
210 }
211
212 /* NB: override anything set in ah_init0 */
213 sav->tdb_xform = xsp;
214 sav->tdb_encalgxform = txform;
215
216 /* Initialize crypto session. */
217 bzero(&crie, sizeof (crie));
218 crie.cri_alg = sav->tdb_encalgxform->type;
219 crie.cri_klen = _KEYBITS(sav->key_enc);
220 crie.cri_key = _KEYBUF(sav->key_enc);
221 /* XXX Rounds ? */
222
223 if (sav->tdb_authalgxform && sav->tdb_encalgxform) {
224 /* init both auth & enc */
225 crie.cri_next = &cria;
226 error = crypto_newsession(&sav->tdb_cryptoid,
227 &crie, crypto_support);
228 } else if (sav->tdb_encalgxform) {
229 error = crypto_newsession(&sav->tdb_cryptoid,
230 &crie, crypto_support);
231 } else if (sav->tdb_authalgxform) {
232 error = crypto_newsession(&sav->tdb_cryptoid,
233 &cria, crypto_support);
234 } else {
235 /* XXX cannot happen? */
236 DPRINTF(("%s: no encoding OR authentication xform!\n",
237 __func__));
238 error = EINVAL;
239 }
240 return error;
241 }
242
243 /*
244 * Paranoia.
245 */
246 static int
247 esp_zeroize(struct secasvar *sav)
248 {
249 /* NB: ah_zerorize free's the crypto session state */
250 int error = ah_zeroize(sav);
251
252 if (sav->key_enc)
253 bzero(_KEYBUF(sav->key_enc), _KEYLEN(sav->key_enc));
254 if (sav->iv) {
255 free(sav->iv, M_XDATA);
256 sav->iv = NULL;
257 }
258 sav->tdb_encalgxform = NULL;
259 sav->tdb_xform = NULL;
260 return error;
261 }
262
263 /*
264 * ESP input processing, called (eventually) through the protocol switch.
265 */
266 static int
267 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
268 {
269 struct auth_hash *esph;
270 struct enc_xform *espx;
271 struct tdb_ident *tdbi;
272 struct tdb_crypto *tc;
273 int plen, alen, hlen;
274 struct m_tag *mtag;
275 struct newesp *esp;
276
277 struct cryptodesc *crde;
278 struct cryptop *crp;
279
280 IPSEC_SPLASSERT_SOFTNET(__func__);
281
282 IPSEC_ASSERT(sav != NULL, ("null SA"));
283 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform"));
284 IPSEC_ASSERT((skip&3) == 0 && (m->m_pkthdr.len&3) == 0,
285 ("misaligned packet, skip %u pkt len %u",
286 skip, m->m_pkthdr.len));
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 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 /* Authenticator hash size */
300 alen = esph ? AH_HMAC_HASHLEN : 0;
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__,
314 plen, espx->blocksize,
315 ipsec_address(&sav->sah->saidx.dst),
316 (u_long) ntohl(sav->spi)));
317 espstat.esps_badilen++;
318 m_freem(m);
319 return EINVAL;
320 }
321
322 /*
323 * Check sequence number.
324 */
325 if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) {
326 DPRINTF(("%s: packet replay check for %s\n", __func__,
327 ipsec_logsastr(sav))); /*XXX*/
328 espstat.esps_replay++;
329 m_freem(m);
330 return ENOBUFS; /*XXX*/
331 }
332
333 /* Update the counters */
334 espstat.esps_ibytes += m->m_pkthdr.len - (skip + hlen + alen);
335
336 /* Find out if we've already done crypto */
337 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL);
338 mtag != NULL;
339 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) {
340 tdbi = (struct tdb_ident *) (mtag + 1);
341 if (tdbi->proto == sav->sah->saidx.proto &&
342 tdbi->spi == sav->spi &&
343 !bcmp(&tdbi->dst, &sav->sah->saidx.dst,
344 sizeof(union sockaddr_union)))
345 break;
346 }
347
348 /* Get crypto descriptors */
349 crp = crypto_getreq(esph && espx ? 2 : 1);
350 if (crp == NULL) {
351 DPRINTF(("%s: failed to acquire crypto descriptors\n",
352 __func__));
353 espstat.esps_crypto++;
354 m_freem(m);
355 return ENOBUFS;
356 }
357
358 /* Get IPsec-specific opaque pointer */
359 if (esph == NULL || mtag != NULL)
360 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
361 M_XDATA, M_NOWAIT|M_ZERO);
362 else
363 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen,
364 M_XDATA, M_NOWAIT|M_ZERO);
365 if (tc == NULL) {
366 crypto_freereq(crp);
367 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
368 espstat.esps_crypto++;
369 m_freem(m);
370 return ENOBUFS;
371 }
372
373 tc->tc_ptr = (caddr_t) mtag;
374
375 if (esph) {
376 struct cryptodesc *crda = crp->crp_desc;
377
378 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor"));
379
380 /* Authentication descriptor */
381 crda->crd_skip = skip;
382 crda->crd_len = m->m_pkthdr.len - (skip + alen);
383 crda->crd_inject = m->m_pkthdr.len - alen;
384
385 crda->crd_alg = esph->type;
386 crda->crd_key = _KEYBUF(sav->key_auth);
387 crda->crd_klen = _KEYBITS(sav->key_auth);
388
389 /* Copy the authenticator */
390 if (mtag == NULL)
391 m_copydata(m, m->m_pkthdr.len - alen, alen,
392 (caddr_t) (tc + 1));
393
394 /* Chain authentication request */
395 crde = crda->crd_next;
396 } else {
397 crde = crp->crp_desc;
398 }
399
400 /* Crypto operation descriptor */
401 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */
402 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
403 crp->crp_buf = (caddr_t) m;
404 crp->crp_callback = esp_input_cb;
405 crp->crp_sid = sav->tdb_cryptoid;
406 crp->crp_opaque = (caddr_t) tc;
407
408 /* These are passed as-is to the callback */
409 tc->tc_spi = sav->spi;
410 tc->tc_dst = sav->sah->saidx.dst;
411 tc->tc_proto = sav->sah->saidx.proto;
412 tc->tc_protoff = protoff;
413 tc->tc_skip = skip;
414
415 /* Decryption descriptor */
416 if (espx) {
417 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor"));
418 crde->crd_skip = skip + hlen;
419 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
420 crde->crd_inject = skip + hlen - sav->ivlen;
421
422 crde->crd_alg = espx->type;
423 crde->crd_key = _KEYBUF(sav->key_enc);
424 crde->crd_klen = _KEYBITS(sav->key_enc);
425 /* XXX Rounds ? */
426 }
427
428 if (mtag == NULL)
429 return crypto_dispatch(crp);
430 else
431 return esp_input_cb(crp);
432 }
433
434 #ifdef INET6
435 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \
436 if (saidx->dst.sa.sa_family == AF_INET6) { \
437 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \
438 } else { \
439 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \
440 } \
441 } while (0)
442 #else
443 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \
444 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag))
445 #endif
446
447 /*
448 * ESP input callback from the crypto driver.
449 */
450 static int
451 esp_input_cb(struct cryptop *crp)
452 {
453 u_int8_t lastthree[3], aalg[AH_HMAC_HASHLEN];
454 int hlen, skip, protoff, error;
455 struct mbuf *m;
456 struct cryptodesc *crd;
457 struct auth_hash *esph;
458 struct enc_xform *espx;
459 struct tdb_crypto *tc;
460 struct m_tag *mtag;
461 struct secasvar *sav;
462 struct secasindex *saidx;
463 caddr_t ptr;
464
465 NET_LOCK_GIANT();
466
467 crd = crp->crp_desc;
468 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!"));
469
470 tc = (struct tdb_crypto *) crp->crp_opaque;
471 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!"));
472 skip = tc->tc_skip;
473 protoff = tc->tc_protoff;
474 mtag = (struct m_tag *) tc->tc_ptr;
475 m = (struct mbuf *) crp->crp_buf;
476
477 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi);
478 if (sav == NULL) {
479 espstat.esps_notdb++;
480 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n",
481 __func__, ipsec_address(&tc->tc_dst),
482 (u_long) ntohl(tc->tc_spi), tc->tc_proto));
483 error = ENOBUFS; /*XXX*/
484 goto bad;
485 }
486
487 saidx = &sav->sah->saidx;
488 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
489 saidx->dst.sa.sa_family == AF_INET6,
490 ("unexpected protocol family %u", saidx->dst.sa.sa_family));
491
492 esph = sav->tdb_authalgxform;
493 espx = sav->tdb_encalgxform;
494
495 /* Check for crypto errors */
496 if (crp->crp_etype) {
497 /* Reset the session ID */
498 if (sav->tdb_cryptoid != 0)
499 sav->tdb_cryptoid = crp->crp_sid;
500
501 if (crp->crp_etype == EAGAIN) {
502 KEY_FREESAV(&sav);
503 error = crypto_dispatch(crp);
504 NET_UNLOCK_GIANT();
505 return error;
506 }
507
508 espstat.esps_noxform++;
509 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
510 error = crp->crp_etype;
511 goto bad;
512 }
513
514 /* Shouldn't happen... */
515 if (m == NULL) {
516 espstat.esps_crypto++;
517 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
518 error = EINVAL;
519 goto bad;
520 }
521 espstat.esps_hist[sav->alg_enc]++;
522
523 /* If authentication was performed, check now. */
524 if (esph != NULL) {
525 /*
526 * If we have a tag, it means an IPsec-aware NIC did
527 * the verification for us. Otherwise we need to
528 * check the authentication calculation.
529 */
530 ahstat.ahs_hist[sav->alg_auth]++;
531 if (mtag == NULL) {
532 /* Copy the authenticator from the packet */
533 m_copydata(m, m->m_pkthdr.len - AH_HMAC_HASHLEN,
534 AH_HMAC_HASHLEN, aalg);
535
536 ptr = (caddr_t) (tc + 1);
537
538 /* Verify authenticator */
539 if (bcmp(ptr, aalg, AH_HMAC_HASHLEN) != 0) {
540 DPRINTF(("%s: "
541 "authentication hash mismatch for packet in SA %s/%08lx\n",
542 __func__,
543 ipsec_address(&saidx->dst),
544 (u_long) ntohl(sav->spi)));
545 espstat.esps_badauth++;
546 error = EACCES;
547 goto bad;
548 }
549 }
550
551 /* Remove trailing authenticator */
552 m_adj(m, -AH_HMAC_HASHLEN);
553 }
554
555 /* Release the crypto descriptors */
556 free(tc, M_XDATA), tc = NULL;
557 crypto_freereq(crp), crp = NULL;
558
559 /*
560 * Packet is now decrypted.
561 */
562 m->m_flags |= M_DECRYPTED;
563
564 /*
565 * Update replay sequence number, if appropriate.
566 */
567 if (sav->replay) {
568 u_int32_t seq;
569
570 m_copydata(m, skip + offsetof(struct newesp, esp_seq),
571 sizeof (seq), (caddr_t) &seq);
572 if (ipsec_updatereplay(ntohl(seq), sav)) {
573 DPRINTF(("%s: packet replay check for %s\n", __func__,
574 ipsec_logsastr(sav)));
575 espstat.esps_replay++;
576 error = ENOBUFS;
577 goto bad;
578 }
579 }
580
581 /* Determine the ESP header length */
582 if (sav->flags & SADB_X_EXT_OLD)
583 hlen = sizeof (struct esp) + sav->ivlen;
584 else
585 hlen = sizeof (struct newesp) + sav->ivlen;
586
587 /* Remove the ESP header and IV from the mbuf. */
588 error = m_striphdr(m, skip, hlen);
589 if (error) {
590 espstat.esps_hdrops++;
591 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__,
592 ipsec_address(&sav->sah->saidx.dst),
593 (u_long) ntohl(sav->spi)));
594 goto bad;
595 }
596
597 /* Save the last three bytes of decrypted data */
598 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree);
599
600 /* Verify pad length */
601 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) {
602 espstat.esps_badilen++;
603 DPRINTF(("%s: invalid padding length %d for %u byte packet "
604 "in SA %s/%08lx\n", __func__,
605 lastthree[1], m->m_pkthdr.len - skip,
606 ipsec_address(&sav->sah->saidx.dst),
607 (u_long) ntohl(sav->spi)));
608 error = EINVAL;
609 goto bad;
610 }
611
612 /* Verify correct decryption by checking the last padding bytes */
613 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) {
614 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) {
615 espstat.esps_badenc++;
616 DPRINTF(("%s: decryption failed for packet in "
617 "SA %s/%08lx\n", __func__,
618 ipsec_address(&sav->sah->saidx.dst),
619 (u_long) ntohl(sav->spi)));
620 error = EINVAL;
621 goto bad;
622 }
623 }
624
625 /* Trim the mbuf chain to remove trailing authenticator and padding */
626 m_adj(m, -(lastthree[1] + 2));
627
628 /* Restore the Next Protocol field */
629 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2);
630
631 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag);
632
633 KEY_FREESAV(&sav);
634 NET_UNLOCK_GIANT();
635 return error;
636 bad:
637 if (sav)
638 KEY_FREESAV(&sav);
639 if (m != NULL)
640 m_freem(m);
641 if (tc != NULL)
642 free(tc, M_XDATA);
643 if (crp != NULL)
644 crypto_freereq(crp);
645 NET_UNLOCK_GIANT();
646 return error;
647 }
648
649 /*
650 * ESP output routine, called by ipsec[46]_process_packet().
651 */
652 static int
653 esp_output(
654 struct mbuf *m,
655 struct ipsecrequest *isr,
656 struct mbuf **mp,
657 int skip,
658 int protoff
659 )
660 {
661 struct enc_xform *espx;
662 struct auth_hash *esph;
663 int hlen, rlen, plen, padding, blks, alen, i, roff;
664 struct mbuf *mo = (struct mbuf *) NULL;
665 struct tdb_crypto *tc;
666 struct secasvar *sav;
667 struct secasindex *saidx;
668 unsigned char *pad;
669 u_int8_t prot;
670 int error, maxpacketsize;
671
672 struct cryptodesc *crde = NULL, *crda = NULL;
673 struct cryptop *crp;
674
675 IPSEC_SPLASSERT_SOFTNET(__func__);
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 * NB: The null encoding transform has a blocksize of 4
691 * so that headers are properly aligned.
692 */
693 blks = espx->blocksize; /* IV blocksize */
694
695 /* XXX clamp padding length a la KAME??? */
696 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;
697 plen = rlen + padding; /* Padded payload length. */
698
699 if (esph)
700 alen = AH_HMAC_HASHLEN;
701 else
702 alen = 0;
703
704 espstat.esps_output++;
705
706 saidx = &sav->sah->saidx;
707 /* Check for maximum packet size violations. */
708 switch (saidx->dst.sa.sa_family) {
709 #ifdef INET
710 case AF_INET:
711 maxpacketsize = IP_MAXPACKET;
712 break;
713 #endif /* INET */
714 #ifdef INET6
715 case AF_INET6:
716 maxpacketsize = IPV6_MAXPACKET;
717 break;
718 #endif /* INET6 */
719 default:
720 DPRINTF(("%s: unknown/unsupported protocol "
721 "family %d, SA %s/%08lx\n", __func__,
722 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst),
723 (u_long) ntohl(sav->spi)));
724 espstat.esps_nopf++;
725 error = EPFNOSUPPORT;
726 goto bad;
727 }
728 if (skip + hlen + rlen + padding + alen > maxpacketsize) {
729 DPRINTF(("%s: packet in SA %s/%08lx got too big "
730 "(len %u, max len %u)\n", __func__,
731 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi),
732 skip + hlen + rlen + padding + alen, maxpacketsize));
733 espstat.esps_toobig++;
734 error = EMSGSIZE;
735 goto bad;
736 }
737
738 /* Update the counters. */
739 espstat.esps_obytes += m->m_pkthdr.len - skip;
740
741 m = m_unshare(m, M_NOWAIT);
742 if (m == NULL) {
743 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__,
744 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
745 espstat.esps_hdrops++;
746 error = ENOBUFS;
747 goto bad;
748 }
749
750 /* Inject ESP header. */
751 mo = m_makespace(m, skip, hlen, &roff);
752 if (mo == NULL) {
753 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n",
754 __func__, hlen, ipsec_address(&saidx->dst),
755 (u_long) ntohl(sav->spi)));
756 espstat.esps_hdrops++; /* XXX diffs from openbsd */
757 error = ENOBUFS;
758 goto bad;
759 }
760
761 /* Initialize ESP header. */
762 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t));
763 if (sav->replay) {
764 u_int32_t replay = htonl(++(sav->replay->count));
765 bcopy((caddr_t) &replay,
766 mtod(mo, caddr_t) + roff + sizeof(u_int32_t),
767 sizeof(u_int32_t));
768 }
769
770 /*
771 * Add padding -- better to do it ourselves than use the crypto engine,
772 * although if/when we support compression, we'd have to do that.
773 */
774 pad = (u_char *) m_pad(m, padding + alen);
775 if (pad == NULL) {
776 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__,
777 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
778 m = NULL; /* NB: free'd by m_pad */
779 error = ENOBUFS;
780 goto bad;
781 }
782
783 /*
784 * Add padding: random, zero, or self-describing.
785 * XXX catch unexpected setting
786 */
787 switch (sav->flags & SADB_X_EXT_PMASK) {
788 case SADB_X_EXT_PRAND:
789 (void) read_random(pad, padding - 2);
790 break;
791 case SADB_X_EXT_PZERO:
792 bzero(pad, padding - 2);
793 break;
794 case SADB_X_EXT_PSEQ:
795 for (i = 0; i < padding - 2; i++)
796 pad[i] = i+1;
797 break;
798 }
799
800 /* Fix padding length and Next Protocol in padding itself. */
801 pad[padding - 2] = padding - 2;
802 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1);
803
804 /* Fix Next Protocol in IPv4/IPv6 header. */
805 prot = IPPROTO_ESP;
806 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot);
807
808 /* Get crypto descriptors. */
809 crp = crypto_getreq(esph && espx ? 2 : 1);
810 if (crp == NULL) {
811 DPRINTF(("%s: failed to acquire crypto descriptors\n",
812 __func__));
813 espstat.esps_crypto++;
814 error = ENOBUFS;
815 goto bad;
816 }
817
818 if (espx) {
819 crde = crp->crp_desc;
820 crda = crde->crd_next;
821
822 /* Encryption descriptor. */
823 crde->crd_skip = skip + hlen;
824 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
825 crde->crd_flags = CRD_F_ENCRYPT;
826 crde->crd_inject = skip + hlen - sav->ivlen;
827
828 /* Encryption operation. */
829 crde->crd_alg = espx->type;
830 crde->crd_key = _KEYBUF(sav->key_enc);
831 crde->crd_klen = _KEYBITS(sav->key_enc);
832 /* XXX Rounds ? */
833 } else
834 crda = crp->crp_desc;
835
836 /* IPsec-specific opaque crypto info. */
837 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
838 M_XDATA, M_NOWAIT|M_ZERO);
839 if (tc == NULL) {
840 crypto_freereq(crp);
841 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
842 espstat.esps_crypto++;
843 error = ENOBUFS;
844 goto bad;
845 }
846
847 /* Callback parameters */
848 tc->tc_isr = isr;
849 tc->tc_spi = sav->spi;
850 tc->tc_dst = saidx->dst;
851 tc->tc_proto = saidx->proto;
852
853 /* Crypto operation descriptor. */
854 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
855 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
856 crp->crp_buf = (caddr_t) m;
857 crp->crp_callback = esp_output_cb;
858 crp->crp_opaque = (caddr_t) tc;
859 crp->crp_sid = sav->tdb_cryptoid;
860
861 if (esph) {
862 /* Authentication descriptor. */
863 crda->crd_skip = skip;
864 crda->crd_len = m->m_pkthdr.len - (skip + alen);
865 crda->crd_inject = m->m_pkthdr.len - alen;
866
867 /* Authentication operation. */
868 crda->crd_alg = esph->type;
869 crda->crd_key = _KEYBUF(sav->key_auth);
870 crda->crd_klen = _KEYBITS(sav->key_auth);
871 }
872
873 return crypto_dispatch(crp);
874 bad:
875 if (m)
876 m_freem(m);
877 return (error);
878 }
879
880 /*
881 * ESP output callback from the crypto driver.
882 */
883 static int
884 esp_output_cb(struct cryptop *crp)
885 {
886 struct tdb_crypto *tc;
887 struct ipsecrequest *isr;
888 struct secasvar *sav;
889 struct mbuf *m;
890 int err, error;
891
892 NET_LOCK_GIANT();
893
894 tc = (struct tdb_crypto *) crp->crp_opaque;
895 IPSEC_ASSERT(tc != NULL, ("null opaque data area!"));
896 m = (struct mbuf *) crp->crp_buf;
897
898 isr = tc->tc_isr;
899 IPSECREQUEST_LOCK(isr);
900 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi);
901 if (sav == NULL) {
902 espstat.esps_notdb++;
903 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n",
904 __func__, ipsec_address(&tc->tc_dst),
905 (u_long) ntohl(tc->tc_spi), tc->tc_proto));
906 error = ENOBUFS; /*XXX*/
907 goto bad;
908 }
909 IPSEC_ASSERT(isr->sav == sav,
910 ("SA changed was %p now %p\n", isr->sav, sav));
911
912 /* Check for crypto errors. */
913 if (crp->crp_etype) {
914 /* Reset session ID. */
915 if (sav->tdb_cryptoid != 0)
916 sav->tdb_cryptoid = crp->crp_sid;
917
918 if (crp->crp_etype == EAGAIN) {
919 KEY_FREESAV(&sav);
920 IPSECREQUEST_UNLOCK(isr);
921 error = crypto_dispatch(crp);
922 NET_UNLOCK_GIANT();
923 return error;
924 }
925
926 espstat.esps_noxform++;
927 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
928 error = crp->crp_etype;
929 goto bad;
930 }
931
932 /* Shouldn't happen... */
933 if (m == NULL) {
934 espstat.esps_crypto++;
935 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
936 error = EINVAL;
937 goto bad;
938 }
939 espstat.esps_hist[sav->alg_enc]++;
940 if (sav->tdb_authalgxform != NULL)
941 ahstat.ahs_hist[sav->alg_auth]++;
942
943 /* Release crypto descriptors. */
944 free(tc, M_XDATA);
945 crypto_freereq(crp);
946
947 /* NB: m is reclaimed by ipsec_process_done. */
948 err = ipsec_process_done(m, isr);
949 KEY_FREESAV(&sav);
950 IPSECREQUEST_UNLOCK(isr);
951 NET_UNLOCK_GIANT();
952 return err;
953 bad:
954 if (sav)
955 KEY_FREESAV(&sav);
956 IPSECREQUEST_UNLOCK(isr);
957 if (m)
958 m_freem(m);
959 free(tc, M_XDATA);
960 crypto_freereq(crp);
961 NET_UNLOCK_GIANT();
962 return error;
963 }
964
965 static struct xformsw esp_xformsw = {
966 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP",
967 esp_init, esp_zeroize, esp_input,
968 esp_output
969 };
970
971 static void
972 esp_attach(void)
973 {
974 #define MAXIV(xform) \
975 if (xform.blocksize > esp_max_ivlen) \
976 esp_max_ivlen = xform.blocksize \
977
978 esp_max_ivlen = 0;
979 MAXIV(enc_xform_des); /* SADB_EALG_DESCBC */
980 MAXIV(enc_xform_3des); /* SADB_EALG_3DESCBC */
981 MAXIV(enc_xform_rijndael128); /* SADB_X_EALG_AES */
982 MAXIV(enc_xform_blf); /* SADB_X_EALG_BLOWFISHCBC */
983 MAXIV(enc_xform_cast5); /* SADB_X_EALG_CAST128CBC */
984 MAXIV(enc_xform_skipjack); /* SADB_X_EALG_SKIPJACK */
985 MAXIV(enc_xform_null); /* SADB_EALG_NULL */
986 MAXIV(enc_xform_camellia); /* SADB_EALG_CAMELLIACBC */
987
988 xform_register(&esp_xformsw);
989 #undef MAXIV
990 }
991 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL);
Cache object: e62bfa3b03cd4c53bd33345bd663171c
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