1 /* $FreeBSD: releng/5.0/sys/netipsec/xform_esp.c 105197 2002-10-16 02:10:08Z sam $ */
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 }
117 return NULL;
118 }
119
120 size_t
121 esp_hdrsiz(struct secasvar *sav)
122 {
123 size_t size;
124
125 if (sav != NULL) {
126 /*XXX not right for null algorithm--does it matter??*/
127 KASSERT(sav->tdb_encalgxform != NULL,
128 ("esp_hdrsiz: SA with null xform"));
129 if (sav->flags & SADB_X_EXT_OLD)
130 size = sizeof (struct esp);
131 else
132 size = sizeof (struct newesp);
133 size += sav->tdb_encalgxform->blocksize + 9;
134 /*XXX need alg check???*/
135 if (sav->tdb_authalgxform != NULL && sav->replay)
136 size += ah_hdrsiz(sav);
137 } else {
138 /*
139 * base header size
140 * + max iv length for CBC mode
141 * + max pad length
142 * + sizeof (pad length field)
143 * + sizeof (next header field)
144 * + max icv supported.
145 */
146 size = sizeof (struct newesp) + esp_max_ivlen + 9 + 16;
147 }
148 return size;
149 }
150
151 /*
152 * esp_init() is called when an SPI is being set up.
153 */
154 static int
155 esp_init(struct secasvar *sav, struct xformsw *xsp)
156 {
157 struct enc_xform *txform;
158 struct cryptoini cria, crie;
159 int keylen;
160 int error;
161
162 txform = esp_algorithm_lookup(sav->alg_enc);
163 if (txform == NULL) {
164 DPRINTF(("esp_init: unsupported encryption algorithm %d\n",
165 sav->alg_enc));
166 return EINVAL;
167 }
168 if (sav->key_enc == NULL) {
169 DPRINTF(("esp_init: no encoding key for %s algorithm\n",
170 txform->name));
171 return EINVAL;
172 }
173 if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) {
174 DPRINTF(("esp_init: 4-byte IV not supported with protocol\n"));
175 return EINVAL;
176 }
177 keylen = _KEYLEN(sav->key_enc);
178 if (txform->minkey > keylen || keylen > txform->maxkey) {
179 DPRINTF(("esp_init: invalid key length %u, must be in "
180 "the range [%u..%u] for algorithm %s\n",
181 keylen, txform->minkey, txform->maxkey,
182 txform->name));
183 return EINVAL;
184 }
185
186 /*
187 * NB: The null xform needs a non-zero blocksize to keep the
188 * crypto code happy but if we use it to set ivlen then
189 * the ESP header will be processed incorrectly. The
190 * compromise is to force it to zero here.
191 */
192 sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize);
193 sav->iv = (caddr_t) malloc(sav->ivlen, M_XDATA, M_WAITOK);
194 if (sav->iv == NULL) {
195 DPRINTF(("esp_init: no memory for IV\n"));
196 return EINVAL;
197 }
198 key_randomfill(sav->iv, sav->ivlen); /*XXX*/
199
200 /*
201 * Setup AH-related state.
202 */
203 if (sav->alg_auth != 0) {
204 error = ah_init0(sav, xsp, &cria);
205 if (error)
206 return error;
207 }
208
209 /* NB: override anything set in ah_init0 */
210 sav->tdb_xform = xsp;
211 sav->tdb_encalgxform = txform;
212
213 /* Initialize crypto session. */
214 bzero(&crie, sizeof (crie));
215 crie.cri_alg = sav->tdb_encalgxform->type;
216 crie.cri_klen = _KEYBITS(sav->key_enc);
217 crie.cri_key = _KEYBUF(sav->key_enc);
218 /* XXX Rounds ? */
219
220 if (sav->tdb_authalgxform && sav->tdb_encalgxform) {
221 /* init both auth & enc */
222 crie.cri_next = &cria;
223 error = crypto_newsession(&sav->tdb_cryptoid,
224 &crie, crypto_support);
225 } else if (sav->tdb_encalgxform) {
226 error = crypto_newsession(&sav->tdb_cryptoid,
227 &crie, crypto_support);
228 } else if (sav->tdb_authalgxform) {
229 error = crypto_newsession(&sav->tdb_cryptoid,
230 &cria, crypto_support);
231 } else {
232 /* XXX cannot happen? */
233 DPRINTF(("esp_init: no encoding OR authentication xform!\n"));
234 error = EINVAL;
235 }
236 return error;
237 }
238
239 /*
240 * Paranoia.
241 */
242 static int
243 esp_zeroize(struct secasvar *sav)
244 {
245 /* NB: ah_zerorize free's the crypto session state */
246 int error = ah_zeroize(sav);
247
248 if (sav->key_enc)
249 bzero(_KEYBUF(sav->key_enc), _KEYLEN(sav->key_enc));
250 /* NB: sav->iv is freed elsewhere, even though we malloc it! */
251 sav->tdb_encalgxform = NULL;
252 sav->tdb_xform = NULL;
253 return error;
254 }
255
256 /*
257 * ESP input processing, called (eventually) through the protocol switch.
258 */
259 static int
260 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
261 {
262 struct auth_hash *esph;
263 struct enc_xform *espx;
264 struct tdb_ident *tdbi;
265 struct tdb_crypto *tc;
266 int plen, alen, hlen;
267 struct m_tag *mtag;
268 struct newesp *esp;
269
270 struct cryptodesc *crde;
271 struct cryptop *crp;
272
273 #if 0
274 SPLASSERT(net, "esp_input");
275 #endif
276
277 KASSERT(sav != NULL, ("esp_input: null SA"));
278 KASSERT(sav->tdb_encalgxform != NULL,
279 ("esp_input: null encoding xform"));
280 KASSERT((skip&3) == 0 && (m->m_pkthdr.len&3) == 0,
281 ("esp_input: misaligned packet, skip %u pkt len %u",
282 skip, m->m_pkthdr.len));
283
284 /* XXX don't pullup, just copy header */
285 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp));
286
287 esph = sav->tdb_authalgxform;
288 espx = sav->tdb_encalgxform;
289
290 /* Determine the ESP header length */
291 if (sav->flags & SADB_X_EXT_OLD)
292 hlen = sizeof (struct esp) + sav->ivlen;
293 else
294 hlen = sizeof (struct newesp) + sav->ivlen;
295 /* Authenticator hash size */
296 alen = esph ? AH_HMAC_HASHLEN : 0;
297
298 /*
299 * Verify payload length is multiple of encryption algorithm
300 * block size.
301 *
302 * NB: This works for the null algorithm because the blocksize
303 * is 4 and all packets must be 4-byte aligned regardless
304 * of the algorithm.
305 */
306 plen = m->m_pkthdr.len - (skip + hlen + alen);
307 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) {
308 DPRINTF(("esp_input: "
309 "payload of %d octets not a multiple of %d octets,"
310 " SA %s/%08lx\n",
311 plen, espx->blocksize,
312 ipsec_address(&sav->sah->saidx.dst),
313 (u_long) ntohl(sav->spi)));
314 espstat.esps_badilen++;
315 m_freem(m);
316 return EINVAL;
317 }
318
319 /*
320 * Check sequence number.
321 */
322 if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) {
323 DPRINTF(("esp_input: packet replay check for %s\n",
324 ipsec_logsastr(sav))); /*XXX*/
325 espstat.esps_replay++;
326 m_freem(m);
327 return ENOBUFS; /*XXX*/
328 }
329
330 /* Update the counters */
331 espstat.esps_ibytes += m->m_pkthdr.len - skip - hlen - alen;
332
333 /* Find out if we've already done crypto */
334 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL);
335 mtag != NULL;
336 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) {
337 tdbi = (struct tdb_ident *) (mtag + 1);
338 if (tdbi->proto == sav->sah->saidx.proto &&
339 tdbi->spi == sav->spi &&
340 !bcmp(&tdbi->dst, &sav->sah->saidx.dst,
341 sizeof(union sockaddr_union)))
342 break;
343 }
344
345 /* Get crypto descriptors */
346 crp = crypto_getreq(esph && espx ? 2 : 1);
347 if (crp == NULL) {
348 DPRINTF(("esp_input: failed to acquire crypto descriptors\n"));
349 espstat.esps_crypto++;
350 m_freem(m);
351 return ENOBUFS;
352 }
353
354 /* Get IPsec-specific opaque pointer */
355 if (esph == NULL || mtag != NULL)
356 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
357 M_XDATA, M_NOWAIT|M_ZERO);
358 else
359 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen,
360 M_XDATA, M_NOWAIT|M_ZERO);
361 if (tc == NULL) {
362 crypto_freereq(crp);
363 DPRINTF(("esp_input: failed to allocate tdb_crypto\n"));
364 espstat.esps_crypto++;
365 m_freem(m);
366 return ENOBUFS;
367 }
368
369 tc->tc_ptr = (caddr_t) mtag;
370
371 if (esph) {
372 struct cryptodesc *crda = crp->crp_desc;
373
374 KASSERT(crda != NULL, ("esp_input: null ah crypto descriptor"));
375
376 /* Authentication descriptor */
377 crda->crd_skip = skip;
378 crda->crd_len = m->m_pkthdr.len - (skip + alen);
379 crda->crd_inject = m->m_pkthdr.len - alen;
380
381 crda->crd_alg = esph->type;
382 crda->crd_key = _KEYBUF(sav->key_auth);
383 crda->crd_klen = _KEYBITS(sav->key_auth);
384
385 /* Copy the authenticator */
386 if (mtag == NULL)
387 m_copydata(m, m->m_pkthdr.len - alen, alen,
388 (caddr_t) (tc + 1));
389
390 /* Chain authentication request */
391 crde = crda->crd_next;
392 } else {
393 crde = crp->crp_desc;
394 }
395
396 /* Crypto operation descriptor */
397 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */
398 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_NODELAY;
399 crp->crp_buf = (caddr_t) m;
400 crp->crp_callback = esp_input_cb;
401 crp->crp_sid = sav->tdb_cryptoid;
402 crp->crp_opaque = (caddr_t) tc;
403
404 /* These are passed as-is to the callback */
405 tc->tc_spi = sav->spi;
406 tc->tc_dst = sav->sah->saidx.dst;
407 tc->tc_proto = sav->sah->saidx.proto;
408 tc->tc_protoff = protoff;
409 tc->tc_skip = skip;
410
411 /* Decryption descriptor */
412 if (espx) {
413 KASSERT(crde != NULL, ("esp_input: null esp crypto descriptor"));
414 crde->crd_skip = skip + hlen;
415 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
416 crde->crd_inject = skip + hlen - sav->ivlen;
417
418 crde->crd_alg = espx->type;
419 crde->crd_key = _KEYBUF(sav->key_enc);
420 crde->crd_klen = _KEYBITS(sav->key_enc);
421 /* XXX Rounds ? */
422 }
423
424 if (mtag == NULL)
425 return crypto_dispatch(crp);
426 else
427 return esp_input_cb(crp);
428 }
429
430 #ifdef INET6
431 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \
432 if (saidx->dst.sa.sa_family == AF_INET6) { \
433 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \
434 } else { \
435 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \
436 } \
437 } while (0)
438 #else
439 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \
440 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag))
441 #endif
442
443 /*
444 * ESP input callback from the crypto driver.
445 */
446 static int
447 esp_input_cb(struct cryptop *crp)
448 {
449 u_int8_t lastthree[3], aalg[AH_HMAC_HASHLEN];
450 int s, hlen, skip, protoff, error;
451 struct mbuf *m;
452 struct cryptodesc *crd;
453 struct auth_hash *esph;
454 struct enc_xform *espx;
455 struct tdb_crypto *tc;
456 struct m_tag *mtag;
457 struct secasvar *sav;
458 struct secasindex *saidx;
459 caddr_t ptr;
460
461 crd = crp->crp_desc;
462 KASSERT(crd != NULL, ("esp_input_cb: null crypto descriptor!"));
463
464 tc = (struct tdb_crypto *) crp->crp_opaque;
465 KASSERT(tc != NULL, ("esp_input_cb: null opaque crypto data area!"));
466 skip = tc->tc_skip;
467 protoff = tc->tc_protoff;
468 mtag = (struct m_tag *) tc->tc_ptr;
469 m = (struct mbuf *) crp->crp_buf;
470
471 s = splnet();
472
473 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi);
474 if (sav == NULL) {
475 espstat.esps_notdb++;
476 DPRINTF(("esp_input_cb: SA expired while in crypto "
477 "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst),
478 (u_long) ntohl(tc->tc_spi), tc->tc_proto));
479 error = ENOBUFS; /*XXX*/
480 goto bad;
481 }
482
483 saidx = &sav->sah->saidx;
484 KASSERT(saidx->dst.sa.sa_family == AF_INET ||
485 saidx->dst.sa.sa_family == AF_INET6,
486 ("ah_input_cb: unexpected protocol family %u",
487 saidx->dst.sa.sa_family));
488
489 esph = sav->tdb_authalgxform;
490 espx = sav->tdb_encalgxform;
491
492 /* Check for crypto errors */
493 if (crp->crp_etype) {
494 /* Reset the session ID */
495 if (sav->tdb_cryptoid != 0)
496 sav->tdb_cryptoid = crp->crp_sid;
497
498 if (crp->crp_etype == EAGAIN) {
499 KEY_FREESAV(&sav);
500 splx(s);
501 return crypto_dispatch(crp);
502 }
503
504 espstat.esps_noxform++;
505 DPRINTF(("esp_input_cb: crypto error %d\n", crp->crp_etype));
506 error = crp->crp_etype;
507 goto bad;
508 }
509
510 /* Shouldn't happen... */
511 if (m == NULL) {
512 espstat.esps_crypto++;
513 DPRINTF(("esp_input_cb: bogus returned buffer from crypto\n"));
514 error = EINVAL;
515 goto bad;
516 }
517 espstat.esps_hist[sav->alg_enc]++;
518
519 /* If authentication was performed, check now. */
520 if (esph != NULL) {
521 /*
522 * If we have a tag, it means an IPsec-aware NIC did
523 * the verification for us. Otherwise we need to
524 * check the authentication calculation.
525 */
526 ahstat.ahs_hist[sav->alg_auth]++;
527 if (mtag == NULL) {
528 /* Copy the authenticator from the packet */
529 m_copydata(m, m->m_pkthdr.len - esph->authsize,
530 esph->authsize, aalg);
531
532 ptr = (caddr_t) (tc + 1);
533
534 /* Verify authenticator */
535 if (bcmp(ptr, aalg, esph->authsize) != 0) {
536 DPRINTF(("esp_input_cb: "
537 "authentication hash mismatch for packet in SA %s/%08lx\n",
538 ipsec_address(&saidx->dst),
539 (u_long) ntohl(sav->spi)));
540 espstat.esps_badauth++;
541 error = EACCES;
542 goto bad;
543 }
544 }
545
546 /* Remove trailing authenticator */
547 m_adj(m, -(esph->authsize));
548 }
549
550 /* Release the crypto descriptors */
551 free(tc, M_XDATA), tc = NULL;
552 crypto_freereq(crp), crp = NULL;
553
554 /*
555 * Packet is now decrypted.
556 */
557 m->m_flags |= M_DECRYPTED;
558
559 /* Determine the ESP header length */
560 if (sav->flags & SADB_X_EXT_OLD)
561 hlen = sizeof (struct esp) + sav->ivlen;
562 else
563 hlen = sizeof (struct newesp) + sav->ivlen;
564
565 /* Remove the ESP header and IV from the mbuf. */
566 error = m_striphdr(m, skip, hlen);
567 if (error) {
568 espstat.esps_hdrops++;
569 DPRINTF(("esp_input_cb: bad mbuf chain, SA %s/%08lx\n",
570 ipsec_address(&sav->sah->saidx.dst),
571 (u_long) ntohl(sav->spi)));
572 goto bad;
573 }
574
575 /* Save the last three bytes of decrypted data */
576 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree);
577
578 /* Verify pad length */
579 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) {
580 espstat.esps_badilen++;
581 DPRINTF(("esp_input_cb: invalid padding length %d "
582 "for %u byte packet in SA %s/%08lx\n",
583 lastthree[1], m->m_pkthdr.len - skip,
584 ipsec_address(&sav->sah->saidx.dst),
585 (u_long) ntohl(sav->spi)));
586 error = EINVAL;
587 goto bad;
588 }
589
590 /* Verify correct decryption by checking the last padding bytes */
591 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) {
592 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) {
593 espstat.esps_badenc++;
594 DPRINTF(("esp_input_cb: decryption failed "
595 "for packet in SA %s/%08lx\n",
596 ipsec_address(&sav->sah->saidx.dst),
597 (u_long) ntohl(sav->spi)));
598 DPRINTF(("esp_input_cb: %x %x\n", lastthree[0], lastthree[1]));
599 error = EINVAL;
600 goto bad;
601 }
602 }
603
604 /* Trim the mbuf chain to remove trailing authenticator and padding */
605 m_adj(m, -(lastthree[1] + 2));
606
607 /* Restore the Next Protocol field */
608 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2);
609
610 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag);
611
612 KEY_FREESAV(&sav);
613 splx(s);
614 return error;
615 bad:
616 if (sav)
617 KEY_FREESAV(&sav);
618 splx(s);
619 if (m != NULL)
620 m_freem(m);
621 if (tc != NULL)
622 free(tc, M_XDATA);
623 if (crp != NULL)
624 crypto_freereq(crp);
625 return error;
626 }
627
628 /*
629 * ESP output routine, called by ipsec[46]_process_packet().
630 */
631 static int
632 esp_output(
633 struct mbuf *m,
634 struct ipsecrequest *isr,
635 struct mbuf **mp,
636 int skip,
637 int protoff
638 )
639 {
640 struct enc_xform *espx;
641 struct auth_hash *esph;
642 int hlen, rlen, plen, padding, blks, alen, i, roff;
643 struct mbuf *mo = (struct mbuf *) NULL;
644 struct tdb_crypto *tc;
645 struct secasvar *sav;
646 struct secasindex *saidx;
647 unsigned char *pad;
648 u_int8_t prot;
649 int error, maxpacketsize;
650
651 struct cryptodesc *crde = NULL, *crda = NULL;
652 struct cryptop *crp;
653
654 #if 0
655 SPLASSERT(net, "esp_output");
656 #endif
657
658 sav = isr->sav;
659 KASSERT(sav != NULL, ("esp_output: null SA"));
660 esph = sav->tdb_authalgxform;
661 espx = sav->tdb_encalgxform;
662 KASSERT(espx != NULL, ("esp_output: null encoding xform"));
663
664 if (sav->flags & SADB_X_EXT_OLD)
665 hlen = sizeof (struct esp) + sav->ivlen;
666 else
667 hlen = sizeof (struct newesp) + sav->ivlen;
668
669 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */
670 /*
671 * NB: The null encoding transform has a blocksize of 4
672 * so that headers are properly aligned.
673 */
674 blks = espx->blocksize; /* IV blocksize */
675
676 /* XXX clamp padding length a la KAME??? */
677 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;
678 plen = rlen + padding; /* Padded payload length. */
679
680 if (esph)
681 alen = AH_HMAC_HASHLEN;
682 else
683 alen = 0;
684
685 espstat.esps_output++;
686
687 saidx = &sav->sah->saidx;
688 /* Check for maximum packet size violations. */
689 switch (saidx->dst.sa.sa_family) {
690 #ifdef INET
691 case AF_INET:
692 maxpacketsize = IP_MAXPACKET;
693 break;
694 #endif /* INET */
695 #ifdef INET6
696 case AF_INET6:
697 maxpacketsize = IPV6_MAXPACKET;
698 break;
699 #endif /* INET6 */
700 default:
701 DPRINTF(("esp_output: unknown/unsupported protocol "
702 "family %d, SA %s/%08lx\n",
703 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst),
704 (u_long) ntohl(sav->spi)));
705 espstat.esps_nopf++;
706 error = EPFNOSUPPORT;
707 goto bad;
708 }
709 if (skip + hlen + rlen + padding + alen > maxpacketsize) {
710 DPRINTF(("esp_output: packet in SA %s/%08lx got too big "
711 "(len %u, max len %u)\n",
712 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi),
713 skip + hlen + rlen + padding + alen, maxpacketsize));
714 espstat.esps_toobig++;
715 error = EMSGSIZE;
716 goto bad;
717 }
718
719 /* Update the counters. */
720 espstat.esps_obytes += m->m_pkthdr.len - skip;
721
722 m = m_clone(m);
723 if (m == NULL) {
724 DPRINTF(("esp_output: cannot clone mbuf chain, SA %s/%08lx\n",
725 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
726 espstat.esps_hdrops++;
727 error = ENOBUFS;
728 goto bad;
729 }
730
731 /* Inject ESP header. */
732 mo = m_makespace(m, skip, hlen, &roff);
733 if (mo == NULL) {
734 DPRINTF(("esp_output: failed to inject %u byte ESP hdr for SA "
735 "%s/%08lx\n",
736 hlen, ipsec_address(&saidx->dst),
737 (u_long) ntohl(sav->spi)));
738 espstat.esps_hdrops++; /* XXX diffs from openbsd */
739 error = ENOBUFS;
740 goto bad;
741 }
742
743 /* Initialize ESP header. */
744 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t));
745 if (sav->replay) {
746 u_int32_t replay = htonl(++(sav->replay->count));
747 bcopy((caddr_t) &replay,
748 mtod(mo, caddr_t) + roff + sizeof(u_int32_t),
749 sizeof(u_int32_t));
750 }
751
752 /*
753 * Add padding -- better to do it ourselves than use the crypto engine,
754 * although if/when we support compression, we'd have to do that.
755 */
756 pad = (u_char *) m_pad(m, padding + alen);
757 if (pad == NULL) {
758 DPRINTF(("esp_output: m_pad failed for SA %s/%08lx\n",
759 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
760 m = NULL; /* NB: free'd by m_pad */
761 error = ENOBUFS;
762 goto bad;
763 }
764
765 /*
766 * Add padding: random, zero, or self-describing.
767 * XXX catch unexpected setting
768 */
769 switch (sav->flags & SADB_X_EXT_PMASK) {
770 case SADB_X_EXT_PRAND:
771 (void) read_random(pad, padding - 2);
772 break;
773 case SADB_X_EXT_PZERO:
774 bzero(pad, padding - 2);
775 break;
776 case SADB_X_EXT_PSEQ:
777 for (i = 0; i < padding - 2; i++)
778 pad[i] = i+1;
779 break;
780 }
781
782 /* Fix padding length and Next Protocol in padding itself. */
783 pad[padding - 2] = padding - 2;
784 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1);
785
786 /* Fix Next Protocol in IPv4/IPv6 header. */
787 prot = IPPROTO_ESP;
788 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot);
789
790 /* Get crypto descriptors. */
791 crp = crypto_getreq(esph && espx ? 2 : 1);
792 if (crp == NULL) {
793 DPRINTF(("esp_output: failed to acquire crypto descriptors\n"));
794 espstat.esps_crypto++;
795 error = ENOBUFS;
796 goto bad;
797 }
798
799 if (espx) {
800 crde = crp->crp_desc;
801 crda = crde->crd_next;
802
803 /* Encryption descriptor. */
804 crde->crd_skip = skip + hlen;
805 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
806 crde->crd_flags = CRD_F_ENCRYPT;
807 crde->crd_inject = skip + hlen - sav->ivlen;
808
809 /* Encryption operation. */
810 crde->crd_alg = espx->type;
811 crde->crd_key = _KEYBUF(sav->key_enc);
812 crde->crd_klen = _KEYBITS(sav->key_enc);
813 /* XXX Rounds ? */
814 } else
815 crda = crp->crp_desc;
816
817 /* IPsec-specific opaque crypto info. */
818 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
819 M_XDATA, M_NOWAIT|M_ZERO);
820 if (tc == NULL) {
821 crypto_freereq(crp);
822 DPRINTF(("esp_output: failed to allocate tdb_crypto\n"));
823 espstat.esps_crypto++;
824 error = ENOBUFS;
825 goto bad;
826 }
827
828 /* Callback parameters */
829 tc->tc_isr = isr;
830 tc->tc_spi = sav->spi;
831 tc->tc_dst = saidx->dst;
832 tc->tc_proto = saidx->proto;
833
834 /* Crypto operation descriptor. */
835 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
836 crp->crp_flags = CRYPTO_F_IMBUF;
837 crp->crp_buf = (caddr_t) m;
838 crp->crp_callback = esp_output_cb;
839 crp->crp_opaque = (caddr_t) tc;
840 crp->crp_sid = sav->tdb_cryptoid;
841
842 if (esph) {
843 /* Authentication descriptor. */
844 crda->crd_skip = skip;
845 crda->crd_len = m->m_pkthdr.len - (skip + alen);
846 crda->crd_inject = m->m_pkthdr.len - alen;
847
848 /* Authentication operation. */
849 crda->crd_alg = esph->type;
850 crda->crd_key = _KEYBUF(sav->key_auth);
851 crda->crd_klen = _KEYBITS(sav->key_auth);
852 }
853
854 return crypto_dispatch(crp);
855 bad:
856 if (m)
857 m_freem(m);
858 return (error);
859 }
860
861 /*
862 * ESP output callback from the crypto driver.
863 */
864 static int
865 esp_output_cb(struct cryptop *crp)
866 {
867 struct tdb_crypto *tc;
868 struct ipsecrequest *isr;
869 struct secasvar *sav;
870 struct mbuf *m;
871 int s, err, error;
872
873 tc = (struct tdb_crypto *) crp->crp_opaque;
874 KASSERT(tc != NULL, ("esp_output_cb: null opaque data area!"));
875 m = (struct mbuf *) crp->crp_buf;
876
877 s = splnet();
878
879 isr = tc->tc_isr;
880 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi);
881 if (sav == NULL) {
882 espstat.esps_notdb++;
883 DPRINTF(("esp_output_cb: SA expired while in crypto "
884 "(SA %s/%08lx proto %u)\n", ipsec_address(&tc->tc_dst),
885 (u_long) ntohl(tc->tc_spi), tc->tc_proto));
886 error = ENOBUFS; /*XXX*/
887 goto bad;
888 }
889 KASSERT(isr->sav == sav,
890 ("esp_output_cb: SA changed was %p now %p\n", isr->sav, sav));
891
892 /* Check for crypto errors. */
893 if (crp->crp_etype) {
894 /* Reset session ID. */
895 if (sav->tdb_cryptoid != 0)
896 sav->tdb_cryptoid = crp->crp_sid;
897
898 if (crp->crp_etype == EAGAIN) {
899 KEY_FREESAV(&sav);
900 splx(s);
901 return crypto_dispatch(crp);
902 }
903
904 espstat.esps_noxform++;
905 DPRINTF(("esp_output_cb: crypto error %d\n", crp->crp_etype));
906 error = crp->crp_etype;
907 goto bad;
908 }
909
910 /* Shouldn't happen... */
911 if (m == NULL) {
912 espstat.esps_crypto++;
913 DPRINTF(("esp_output_cb: bogus returned buffer from crypto\n"));
914 error = EINVAL;
915 goto bad;
916 }
917 espstat.esps_hist[sav->alg_enc]++;
918 if (sav->tdb_authalgxform != NULL)
919 ahstat.ahs_hist[sav->alg_auth]++;
920
921 /* Release crypto descriptors. */
922 free(tc, M_XDATA);
923 crypto_freereq(crp);
924
925 /* NB: m is reclaimed by ipsec_process_done. */
926 err = ipsec_process_done(m, isr);
927 KEY_FREESAV(&sav);
928 splx(s);
929 return err;
930 bad:
931 if (sav)
932 KEY_FREESAV(&sav);
933 splx(s);
934 if (m)
935 m_freem(m);
936 free(tc, M_XDATA);
937 crypto_freereq(crp);
938 return error;
939 }
940
941 static struct xformsw esp_xformsw = {
942 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP",
943 esp_init, esp_zeroize, esp_input,
944 esp_output
945 };
946
947 static void
948 esp_attach(void)
949 {
950 #define MAXIV(xform) \
951 if (xform.blocksize > esp_max_ivlen) \
952 esp_max_ivlen = xform.blocksize \
953
954 esp_max_ivlen = 0;
955 MAXIV(enc_xform_des); /* SADB_EALG_DESCBC */
956 MAXIV(enc_xform_3des); /* SADB_EALG_3DESCBC */
957 MAXIV(enc_xform_rijndael128); /* SADB_X_EALG_AES */
958 MAXIV(enc_xform_blf); /* SADB_X_EALG_BLOWFISHCBC */
959 MAXIV(enc_xform_cast5); /* SADB_X_EALG_CAST128CBC */
960 MAXIV(enc_xform_skipjack); /* SADB_X_EALG_SKIPJACK */
961 MAXIV(enc_xform_null); /* SADB_EALG_NULL */
962
963 xform_register(&esp_xformsw);
964 #undef MAXIV
965 }
966 SYSINIT(esp_xform_init, SI_SUB_DRIVERS, SI_ORDER_FIRST, esp_attach, NULL)
Cache object: 7714d02fb4bfb1a35c1d85311b95dfd8
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