1 /* $FreeBSD$ */
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 = sav->key_enc->key_data;
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(sav->key_enc->key_data, _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 = sav->key_auth->key_data;
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 = sav->key_enc->key_data;
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 crd = crp->crp_desc;
466 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!"));
467
468 tc = (struct tdb_crypto *) crp->crp_opaque;
469 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!"));
470 skip = tc->tc_skip;
471 protoff = tc->tc_protoff;
472 mtag = (struct m_tag *) tc->tc_ptr;
473 m = (struct mbuf *) crp->crp_buf;
474
475 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi);
476 if (sav == NULL) {
477 espstat.esps_notdb++;
478 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n",
479 __func__, ipsec_address(&tc->tc_dst),
480 (u_long) ntohl(tc->tc_spi), tc->tc_proto));
481 error = ENOBUFS; /*XXX*/
482 goto bad;
483 }
484
485 saidx = &sav->sah->saidx;
486 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
487 saidx->dst.sa.sa_family == AF_INET6,
488 ("unexpected protocol family %u", saidx->dst.sa.sa_family));
489
490 esph = sav->tdb_authalgxform;
491 espx = sav->tdb_encalgxform;
492
493 /* Check for crypto errors */
494 if (crp->crp_etype) {
495 /* Reset the session ID */
496 if (sav->tdb_cryptoid != 0)
497 sav->tdb_cryptoid = crp->crp_sid;
498
499 if (crp->crp_etype == EAGAIN) {
500 KEY_FREESAV(&sav);
501 error = crypto_dispatch(crp);
502 return error;
503 }
504
505 espstat.esps_noxform++;
506 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
507 error = crp->crp_etype;
508 goto bad;
509 }
510
511 /* Shouldn't happen... */
512 if (m == NULL) {
513 espstat.esps_crypto++;
514 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
515 error = EINVAL;
516 goto bad;
517 }
518 espstat.esps_hist[sav->alg_enc]++;
519
520 /* If authentication was performed, check now. */
521 if (esph != NULL) {
522 /*
523 * If we have a tag, it means an IPsec-aware NIC did
524 * the verification for us. Otherwise we need to
525 * check the authentication calculation.
526 */
527 ahstat.ahs_hist[sav->alg_auth]++;
528 if (mtag == NULL) {
529 /* Copy the authenticator from the packet */
530 m_copydata(m, m->m_pkthdr.len - AH_HMAC_HASHLEN,
531 AH_HMAC_HASHLEN, aalg);
532
533 ptr = (caddr_t) (tc + 1);
534
535 /* Verify authenticator */
536 if (bcmp(ptr, aalg, AH_HMAC_HASHLEN) != 0) {
537 DPRINTF(("%s: "
538 "authentication hash mismatch for packet in SA %s/%08lx\n",
539 __func__,
540 ipsec_address(&saidx->dst),
541 (u_long) ntohl(sav->spi)));
542 espstat.esps_badauth++;
543 error = EACCES;
544 goto bad;
545 }
546 }
547
548 /* Remove trailing authenticator */
549 m_adj(m, -AH_HMAC_HASHLEN);
550 }
551
552 /* Release the crypto descriptors */
553 free(tc, M_XDATA), tc = NULL;
554 crypto_freereq(crp), crp = NULL;
555
556 /*
557 * Packet is now decrypted.
558 */
559 m->m_flags |= M_DECRYPTED;
560
561 /*
562 * Update replay sequence number, if appropriate.
563 */
564 if (sav->replay) {
565 u_int32_t seq;
566
567 m_copydata(m, skip + offsetof(struct newesp, esp_seq),
568 sizeof (seq), (caddr_t) &seq);
569 if (ipsec_updatereplay(ntohl(seq), sav)) {
570 DPRINTF(("%s: packet replay check for %s\n", __func__,
571 ipsec_logsastr(sav)));
572 espstat.esps_replay++;
573 error = ENOBUFS;
574 goto bad;
575 }
576 }
577
578 /* Determine the ESP header length */
579 if (sav->flags & SADB_X_EXT_OLD)
580 hlen = sizeof (struct esp) + sav->ivlen;
581 else
582 hlen = sizeof (struct newesp) + sav->ivlen;
583
584 /* Remove the ESP header and IV from the mbuf. */
585 error = m_striphdr(m, skip, hlen);
586 if (error) {
587 espstat.esps_hdrops++;
588 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__,
589 ipsec_address(&sav->sah->saidx.dst),
590 (u_long) ntohl(sav->spi)));
591 goto bad;
592 }
593
594 /* Save the last three bytes of decrypted data */
595 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree);
596
597 /* Verify pad length */
598 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) {
599 espstat.esps_badilen++;
600 DPRINTF(("%s: invalid padding length %d for %u byte packet "
601 "in SA %s/%08lx\n", __func__,
602 lastthree[1], m->m_pkthdr.len - skip,
603 ipsec_address(&sav->sah->saidx.dst),
604 (u_long) ntohl(sav->spi)));
605 error = EINVAL;
606 goto bad;
607 }
608
609 /* Verify correct decryption by checking the last padding bytes */
610 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) {
611 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) {
612 espstat.esps_badenc++;
613 DPRINTF(("%s: decryption failed for packet in "
614 "SA %s/%08lx\n", __func__,
615 ipsec_address(&sav->sah->saidx.dst),
616 (u_long) ntohl(sav->spi)));
617 error = EINVAL;
618 goto bad;
619 }
620 }
621
622 /* Trim the mbuf chain to remove trailing authenticator and padding */
623 m_adj(m, -(lastthree[1] + 2));
624
625 /* Restore the Next Protocol field */
626 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2);
627
628 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag);
629
630 KEY_FREESAV(&sav);
631 return error;
632 bad:
633 if (sav)
634 KEY_FREESAV(&sav);
635 if (m != NULL)
636 m_freem(m);
637 if (tc != NULL)
638 free(tc, M_XDATA);
639 if (crp != NULL)
640 crypto_freereq(crp);
641 return error;
642 }
643
644 /*
645 * ESP output routine, called by ipsec[46]_process_packet().
646 */
647 static int
648 esp_output(
649 struct mbuf *m,
650 struct ipsecrequest *isr,
651 struct mbuf **mp,
652 int skip,
653 int protoff
654 )
655 {
656 struct enc_xform *espx;
657 struct auth_hash *esph;
658 int hlen, rlen, plen, padding, blks, alen, i, roff;
659 struct mbuf *mo = (struct mbuf *) NULL;
660 struct tdb_crypto *tc;
661 struct secasvar *sav;
662 struct secasindex *saidx;
663 unsigned char *pad;
664 u_int8_t prot;
665 int error, maxpacketsize;
666
667 struct cryptodesc *crde = NULL, *crda = NULL;
668 struct cryptop *crp;
669
670 IPSEC_SPLASSERT_SOFTNET(__func__);
671
672 sav = isr->sav;
673 IPSEC_ASSERT(sav != NULL, ("null SA"));
674 esph = sav->tdb_authalgxform;
675 espx = sav->tdb_encalgxform;
676 IPSEC_ASSERT(espx != NULL, ("null encoding xform"));
677
678 if (sav->flags & SADB_X_EXT_OLD)
679 hlen = sizeof (struct esp) + sav->ivlen;
680 else
681 hlen = sizeof (struct newesp) + sav->ivlen;
682
683 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */
684 /*
685 * NB: The null encoding transform has a blocksize of 4
686 * so that headers are properly aligned.
687 */
688 blks = espx->blocksize; /* IV blocksize */
689
690 /* XXX clamp padding length a la KAME??? */
691 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;
692 plen = rlen + padding; /* Padded payload length. */
693
694 if (esph)
695 alen = AH_HMAC_HASHLEN;
696 else
697 alen = 0;
698
699 espstat.esps_output++;
700
701 saidx = &sav->sah->saidx;
702 /* Check for maximum packet size violations. */
703 switch (saidx->dst.sa.sa_family) {
704 #ifdef INET
705 case AF_INET:
706 maxpacketsize = IP_MAXPACKET;
707 break;
708 #endif /* INET */
709 #ifdef INET6
710 case AF_INET6:
711 maxpacketsize = IPV6_MAXPACKET;
712 break;
713 #endif /* INET6 */
714 default:
715 DPRINTF(("%s: unknown/unsupported protocol "
716 "family %d, SA %s/%08lx\n", __func__,
717 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst),
718 (u_long) ntohl(sav->spi)));
719 espstat.esps_nopf++;
720 error = EPFNOSUPPORT;
721 goto bad;
722 }
723 if (skip + hlen + rlen + padding + alen > maxpacketsize) {
724 DPRINTF(("%s: packet in SA %s/%08lx got too big "
725 "(len %u, max len %u)\n", __func__,
726 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi),
727 skip + hlen + rlen + padding + alen, maxpacketsize));
728 espstat.esps_toobig++;
729 error = EMSGSIZE;
730 goto bad;
731 }
732
733 /* Update the counters. */
734 espstat.esps_obytes += m->m_pkthdr.len - skip;
735
736 m = m_unshare(m, M_NOWAIT);
737 if (m == NULL) {
738 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__,
739 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
740 espstat.esps_hdrops++;
741 error = ENOBUFS;
742 goto bad;
743 }
744
745 /* Inject ESP header. */
746 mo = m_makespace(m, skip, hlen, &roff);
747 if (mo == NULL) {
748 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n",
749 __func__, hlen, ipsec_address(&saidx->dst),
750 (u_long) ntohl(sav->spi)));
751 espstat.esps_hdrops++; /* XXX diffs from openbsd */
752 error = ENOBUFS;
753 goto bad;
754 }
755
756 /* Initialize ESP header. */
757 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t));
758 if (sav->replay) {
759 u_int32_t replay;
760
761 #ifdef REGRESSION
762 /* Emulate replay attack when ipsec_replay is TRUE. */
763 if (!ipsec_replay)
764 #endif
765 sav->replay->count++;
766 replay = htonl(sav->replay->count);
767 bcopy((caddr_t) &replay,
768 mtod(mo, caddr_t) + roff + sizeof(u_int32_t),
769 sizeof(u_int32_t));
770 }
771
772 /*
773 * Add padding -- better to do it ourselves than use the crypto engine,
774 * although if/when we support compression, we'd have to do that.
775 */
776 pad = (u_char *) m_pad(m, padding + alen);
777 if (pad == NULL) {
778 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__,
779 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
780 m = NULL; /* NB: free'd by m_pad */
781 error = ENOBUFS;
782 goto bad;
783 }
784
785 /*
786 * Add padding: random, zero, or self-describing.
787 * XXX catch unexpected setting
788 */
789 switch (sav->flags & SADB_X_EXT_PMASK) {
790 case SADB_X_EXT_PRAND:
791 (void) read_random(pad, padding - 2);
792 break;
793 case SADB_X_EXT_PZERO:
794 bzero(pad, padding - 2);
795 break;
796 case SADB_X_EXT_PSEQ:
797 for (i = 0; i < padding - 2; i++)
798 pad[i] = i+1;
799 break;
800 }
801
802 /* Fix padding length and Next Protocol in padding itself. */
803 pad[padding - 2] = padding - 2;
804 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1);
805
806 /* Fix Next Protocol in IPv4/IPv6 header. */
807 prot = IPPROTO_ESP;
808 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot);
809
810 /* Get crypto descriptors. */
811 crp = crypto_getreq(esph && espx ? 2 : 1);
812 if (crp == NULL) {
813 DPRINTF(("%s: failed to acquire crypto descriptors\n",
814 __func__));
815 espstat.esps_crypto++;
816 error = ENOBUFS;
817 goto bad;
818 }
819
820 if (espx) {
821 crde = crp->crp_desc;
822 crda = crde->crd_next;
823
824 /* Encryption descriptor. */
825 crde->crd_skip = skip + hlen;
826 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
827 crde->crd_flags = CRD_F_ENCRYPT;
828 crde->crd_inject = skip + hlen - sav->ivlen;
829
830 /* Encryption operation. */
831 crde->crd_alg = espx->type;
832 crde->crd_key = sav->key_enc->key_data;
833 crde->crd_klen = _KEYBITS(sav->key_enc);
834 /* XXX Rounds ? */
835 } else
836 crda = crp->crp_desc;
837
838 /* IPsec-specific opaque crypto info. */
839 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
840 M_XDATA, M_NOWAIT|M_ZERO);
841 if (tc == NULL) {
842 crypto_freereq(crp);
843 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
844 espstat.esps_crypto++;
845 error = ENOBUFS;
846 goto bad;
847 }
848
849 /* Callback parameters */
850 tc->tc_isr = isr;
851 tc->tc_spi = sav->spi;
852 tc->tc_dst = saidx->dst;
853 tc->tc_proto = saidx->proto;
854
855 /* Crypto operation descriptor. */
856 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
857 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
858 crp->crp_buf = (caddr_t) m;
859 crp->crp_callback = esp_output_cb;
860 crp->crp_opaque = (caddr_t) tc;
861 crp->crp_sid = sav->tdb_cryptoid;
862
863 if (esph) {
864 /* Authentication descriptor. */
865 crda->crd_skip = skip;
866 crda->crd_len = m->m_pkthdr.len - (skip + alen);
867 crda->crd_inject = m->m_pkthdr.len - alen;
868
869 /* Authentication operation. */
870 crda->crd_alg = esph->type;
871 crda->crd_key = sav->key_auth->key_data;
872 crda->crd_klen = _KEYBITS(sav->key_auth);
873 }
874
875 return crypto_dispatch(crp);
876 bad:
877 if (m)
878 m_freem(m);
879 return (error);
880 }
881
882 /*
883 * ESP output callback from the crypto driver.
884 */
885 static int
886 esp_output_cb(struct cryptop *crp)
887 {
888 struct tdb_crypto *tc;
889 struct ipsecrequest *isr;
890 struct secasvar *sav;
891 struct mbuf *m;
892 int err, error;
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 return error;
923 }
924
925 espstat.esps_noxform++;
926 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
927 error = crp->crp_etype;
928 goto bad;
929 }
930
931 /* Shouldn't happen... */
932 if (m == NULL) {
933 espstat.esps_crypto++;
934 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
935 error = EINVAL;
936 goto bad;
937 }
938 espstat.esps_hist[sav->alg_enc]++;
939 if (sav->tdb_authalgxform != NULL)
940 ahstat.ahs_hist[sav->alg_auth]++;
941
942 /* Release crypto descriptors. */
943 free(tc, M_XDATA);
944 crypto_freereq(crp);
945
946 #ifdef REGRESSION
947 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
948 if (ipsec_integrity) {
949 static unsigned char ipseczeroes[AH_HMAC_HASHLEN];
950 struct auth_hash *esph;
951
952 /*
953 * Corrupt HMAC if we want to test integrity verification of
954 * the other side.
955 */
956 esph = sav->tdb_authalgxform;
957 if (esph != NULL) {
958 m_copyback(m, m->m_pkthdr.len - AH_HMAC_HASHLEN,
959 AH_HMAC_HASHLEN, ipseczeroes);
960 }
961 }
962 #endif
963
964 /* NB: m is reclaimed by ipsec_process_done. */
965 err = ipsec_process_done(m, isr);
966 KEY_FREESAV(&sav);
967 IPSECREQUEST_UNLOCK(isr);
968 return err;
969 bad:
970 if (sav)
971 KEY_FREESAV(&sav);
972 IPSECREQUEST_UNLOCK(isr);
973 if (m)
974 m_freem(m);
975 free(tc, M_XDATA);
976 crypto_freereq(crp);
977 return error;
978 }
979
980 static struct xformsw esp_xformsw = {
981 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP",
982 esp_init, esp_zeroize, esp_input,
983 esp_output
984 };
985
986 static void
987 esp_attach(void)
988 {
989 #define MAXIV(xform) \
990 if (xform.blocksize > esp_max_ivlen) \
991 esp_max_ivlen = xform.blocksize \
992
993 esp_max_ivlen = 0;
994 MAXIV(enc_xform_des); /* SADB_EALG_DESCBC */
995 MAXIV(enc_xform_3des); /* SADB_EALG_3DESCBC */
996 MAXIV(enc_xform_rijndael128); /* SADB_X_EALG_AES */
997 MAXIV(enc_xform_blf); /* SADB_X_EALG_BLOWFISHCBC */
998 MAXIV(enc_xform_cast5); /* SADB_X_EALG_CAST128CBC */
999 MAXIV(enc_xform_skipjack); /* SADB_X_EALG_SKIPJACK */
1000 MAXIV(enc_xform_null); /* SADB_EALG_NULL */
1001 MAXIV(enc_xform_camellia); /* SADB_X_EALG_CAMELLIACBC */
1002
1003 xform_register(&esp_xformsw);
1004 #undef MAXIV
1005 }
1006 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL);
Cache object: 8e4e779d82a4ae62dd9ddac5dc8b23fa
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