1 /* $FreeBSD: src/sys/netipsec/xform_esp.c,v 1.23 2008/10/02 15:37:58 zec Exp $ */
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 #include <sys/vimage.h>
50
51 #include <net/if.h>
52
53 #include <netinet/in.h>
54 #include <netinet/in_systm.h>
55 #include <netinet/ip.h>
56 #include <netinet/ip_ecn.h>
57 #include <netinet/ip6.h>
58
59 #include <net/route.h>
60 #include <netipsec/ipsec.h>
61 #include <netipsec/ah.h>
62 #include <netipsec/ah_var.h>
63 #include <netipsec/esp.h>
64 #include <netipsec/esp_var.h>
65 #include <netipsec/xform.h>
66
67 #ifdef INET6
68 #include <netinet6/ip6_var.h>
69 #include <netipsec/ipsec6.h>
70 #include <netinet6/ip6_ecn.h>
71 #endif
72
73 #include <netipsec/key.h>
74 #include <netipsec/key_debug.h>
75
76 #include <opencrypto/cryptodev.h>
77 #include <opencrypto/xform.h>
78
79 int esp_enable = 1;
80 struct espstat espstat;
81
82 SYSCTL_DECL(_net_inet_esp);
83 SYSCTL_V_INT(V_NET, vnet_ipsec,_net_inet_esp, OID_AUTO,
84 esp_enable, CTLFLAG_RW, esp_enable, 0, "");
85 SYSCTL_V_STRUCT(V_NET, vnet_ipsec, _net_inet_esp, IPSECCTL_STATS,
86 stats, CTLFLAG_RD, espstat, espstat, "");
87
88 static int esp_max_ivlen; /* max iv length over all algorithms */
89
90 static int esp_input_cb(struct cryptop *op);
91 static int esp_output_cb(struct cryptop *crp);
92
93 /*
94 * NB: this is public for use by the PF_KEY support.
95 * NB: if you add support here; be sure to add code to esp_attach below!
96 */
97 struct enc_xform *
98 esp_algorithm_lookup(int alg)
99 {
100 if (alg >= ESP_ALG_MAX)
101 return NULL;
102 switch (alg) {
103 case SADB_EALG_DESCBC:
104 return &enc_xform_des;
105 case SADB_EALG_3DESCBC:
106 return &enc_xform_3des;
107 case SADB_X_EALG_AES:
108 return &enc_xform_rijndael128;
109 case SADB_X_EALG_BLOWFISHCBC:
110 return &enc_xform_blf;
111 case SADB_X_EALG_CAST128CBC:
112 return &enc_xform_cast5;
113 case SADB_X_EALG_SKIPJACK:
114 return &enc_xform_skipjack;
115 case SADB_EALG_NULL:
116 return &enc_xform_null;
117 case SADB_X_EALG_CAMELLIACBC:
118 return &enc_xform_camellia;
119 }
120 return NULL;
121 }
122
123 size_t
124 esp_hdrsiz(struct secasvar *sav)
125 {
126 INIT_VNET_IPSEC(curvnet);
127 size_t size;
128
129 if (sav != NULL) {
130 /*XXX not right for null algorithm--does it matter??*/
131 IPSEC_ASSERT(sav->tdb_encalgxform != NULL,
132 ("SA with null xform"));
133 if (sav->flags & SADB_X_EXT_OLD)
134 size = sizeof (struct esp);
135 else
136 size = sizeof (struct newesp);
137 size += sav->tdb_encalgxform->blocksize + 9;
138 /*XXX need alg check???*/
139 if (sav->tdb_authalgxform != NULL && sav->replay)
140 size += ah_hdrsiz(sav);
141 } else {
142 /*
143 * base header size
144 * + max iv length for CBC mode
145 * + max pad length
146 * + sizeof (pad length field)
147 * + sizeof (next header field)
148 * + max icv supported.
149 */
150 size = sizeof (struct newesp) + V_esp_max_ivlen + 9 + 16;
151 }
152 return size;
153 }
154
155 /*
156 * esp_init() is called when an SPI is being set up.
157 */
158 static int
159 esp_init(struct secasvar *sav, struct xformsw *xsp)
160 {
161 INIT_VNET_IPSEC(curvnet);
162 struct enc_xform *txform;
163 struct cryptoini cria, crie;
164 int keylen;
165 int error;
166
167 txform = esp_algorithm_lookup(sav->alg_enc);
168 if (txform == NULL) {
169 DPRINTF(("%s: unsupported encryption algorithm %d\n",
170 __func__, sav->alg_enc));
171 return EINVAL;
172 }
173 if (sav->key_enc == NULL) {
174 DPRINTF(("%s: no encoding key for %s algorithm\n",
175 __func__, txform->name));
176 return EINVAL;
177 }
178 if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) {
179 DPRINTF(("%s: 4-byte IV not supported with protocol\n",
180 __func__));
181 return EINVAL;
182 }
183 keylen = _KEYLEN(sav->key_enc);
184 if (txform->minkey > keylen || keylen > txform->maxkey) {
185 DPRINTF(("%s: invalid key length %u, must be in the range "
186 "[%u..%u] for algorithm %s\n", __func__,
187 keylen, txform->minkey, txform->maxkey,
188 txform->name));
189 return EINVAL;
190 }
191
192 /*
193 * NB: The null xform needs a non-zero blocksize to keep the
194 * crypto code happy but if we use it to set ivlen then
195 * the ESP header will be processed incorrectly. The
196 * compromise is to force it to zero here.
197 */
198 sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize);
199 sav->iv = (caddr_t) malloc(sav->ivlen, M_XDATA, M_WAITOK);
200 if (sav->iv == NULL) {
201 DPRINTF(("%s: no memory for IV\n", __func__));
202 return EINVAL;
203 }
204 key_randomfill(sav->iv, sav->ivlen); /*XXX*/
205
206 /*
207 * Setup AH-related state.
208 */
209 if (sav->alg_auth != 0) {
210 error = ah_init0(sav, xsp, &cria);
211 if (error)
212 return error;
213 }
214
215 /* NB: override anything set in ah_init0 */
216 sav->tdb_xform = xsp;
217 sav->tdb_encalgxform = txform;
218
219 /* Initialize crypto session. */
220 bzero(&crie, sizeof (crie));
221 crie.cri_alg = sav->tdb_encalgxform->type;
222 crie.cri_klen = _KEYBITS(sav->key_enc);
223 crie.cri_key = sav->key_enc->key_data;
224 /* XXX Rounds ? */
225
226 if (sav->tdb_authalgxform && sav->tdb_encalgxform) {
227 /* init both auth & enc */
228 crie.cri_next = &cria;
229 error = crypto_newsession(&sav->tdb_cryptoid,
230 &crie, V_crypto_support);
231 } else if (sav->tdb_encalgxform) {
232 error = crypto_newsession(&sav->tdb_cryptoid,
233 &crie, V_crypto_support);
234 } else if (sav->tdb_authalgxform) {
235 error = crypto_newsession(&sav->tdb_cryptoid,
236 &cria, V_crypto_support);
237 } else {
238 /* XXX cannot happen? */
239 DPRINTF(("%s: no encoding OR authentication xform!\n",
240 __func__));
241 error = EINVAL;
242 }
243 return error;
244 }
245
246 /*
247 * Paranoia.
248 */
249 static int
250 esp_zeroize(struct secasvar *sav)
251 {
252 /* NB: ah_zerorize free's the crypto session state */
253 int error = ah_zeroize(sav);
254
255 if (sav->key_enc)
256 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc));
257 if (sav->iv) {
258 free(sav->iv, M_XDATA);
259 sav->iv = NULL;
260 }
261 sav->tdb_encalgxform = NULL;
262 sav->tdb_xform = NULL;
263 return error;
264 }
265
266 /*
267 * ESP input processing, called (eventually) through the protocol switch.
268 */
269 static int
270 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
271 {
272 INIT_VNET_IPSEC(curvnet);
273 struct auth_hash *esph;
274 struct enc_xform *espx;
275 struct tdb_ident *tdbi;
276 struct tdb_crypto *tc;
277 int plen, alen, hlen;
278 struct m_tag *mtag;
279 struct newesp *esp;
280
281 struct cryptodesc *crde;
282 struct cryptop *crp;
283
284 IPSEC_ASSERT(sav != NULL, ("null SA"));
285 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform"));
286 IPSEC_ASSERT((skip&3) == 0 && (m->m_pkthdr.len&3) == 0,
287 ("misaligned packet, skip %u pkt len %u",
288 skip, m->m_pkthdr.len));
289
290 /* XXX don't pullup, just copy header */
291 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp));
292
293 esph = sav->tdb_authalgxform;
294 espx = sav->tdb_encalgxform;
295
296 /* Determine the ESP header length */
297 if (sav->flags & SADB_X_EXT_OLD)
298 hlen = sizeof (struct esp) + sav->ivlen;
299 else
300 hlen = sizeof (struct newesp) + sav->ivlen;
301 /* Authenticator hash size */
302 alen = esph ? AH_HMAC_HASHLEN : 0;
303
304 /*
305 * Verify payload length is multiple of encryption algorithm
306 * block size.
307 *
308 * NB: This works for the null algorithm because the blocksize
309 * is 4 and all packets must be 4-byte aligned regardless
310 * of the algorithm.
311 */
312 plen = m->m_pkthdr.len - (skip + hlen + alen);
313 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) {
314 DPRINTF(("%s: payload of %d octets not a multiple of %d octets,"
315 " SA %s/%08lx\n", __func__,
316 plen, espx->blocksize,
317 ipsec_address(&sav->sah->saidx.dst),
318 (u_long) ntohl(sav->spi)));
319 V_espstat.esps_badilen++;
320 m_freem(m);
321 return EINVAL;
322 }
323
324 /*
325 * Check sequence number.
326 */
327 if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) {
328 DPRINTF(("%s: packet replay check for %s\n", __func__,
329 ipsec_logsastr(sav))); /*XXX*/
330 V_espstat.esps_replay++;
331 m_freem(m);
332 return ENOBUFS; /*XXX*/
333 }
334
335 /* Update the counters */
336 V_espstat.esps_ibytes += m->m_pkthdr.len - (skip + hlen + alen);
337
338 /* Find out if we've already done crypto */
339 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL);
340 mtag != NULL;
341 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) {
342 tdbi = (struct tdb_ident *) (mtag + 1);
343 if (tdbi->proto == sav->sah->saidx.proto &&
344 tdbi->spi == sav->spi &&
345 !bcmp(&tdbi->dst, &sav->sah->saidx.dst,
346 sizeof(union sockaddr_union)))
347 break;
348 }
349
350 /* Get crypto descriptors */
351 crp = crypto_getreq(esph && espx ? 2 : 1);
352 if (crp == NULL) {
353 DPRINTF(("%s: failed to acquire crypto descriptors\n",
354 __func__));
355 V_espstat.esps_crypto++;
356 m_freem(m);
357 return ENOBUFS;
358 }
359
360 /* Get IPsec-specific opaque pointer */
361 if (esph == NULL || mtag != NULL)
362 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
363 M_XDATA, M_NOWAIT|M_ZERO);
364 else
365 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen,
366 M_XDATA, M_NOWAIT|M_ZERO);
367 if (tc == NULL) {
368 crypto_freereq(crp);
369 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
370 V_espstat.esps_crypto++;
371 m_freem(m);
372 return ENOBUFS;
373 }
374
375 tc->tc_ptr = (caddr_t) mtag;
376
377 if (esph) {
378 struct cryptodesc *crda = crp->crp_desc;
379
380 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor"));
381
382 /* Authentication descriptor */
383 crda->crd_skip = skip;
384 crda->crd_len = m->m_pkthdr.len - (skip + alen);
385 crda->crd_inject = m->m_pkthdr.len - alen;
386
387 crda->crd_alg = esph->type;
388 crda->crd_key = sav->key_auth->key_data;
389 crda->crd_klen = _KEYBITS(sav->key_auth);
390
391 /* Copy the authenticator */
392 if (mtag == NULL)
393 m_copydata(m, m->m_pkthdr.len - alen, alen,
394 (caddr_t) (tc + 1));
395
396 /* Chain authentication request */
397 crde = crda->crd_next;
398 } else {
399 crde = crp->crp_desc;
400 }
401
402 /* Crypto operation descriptor */
403 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */
404 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
405 crp->crp_buf = (caddr_t) m;
406 crp->crp_callback = esp_input_cb;
407 crp->crp_sid = sav->tdb_cryptoid;
408 crp->crp_opaque = (caddr_t) tc;
409
410 /* These are passed as-is to the callback */
411 tc->tc_spi = sav->spi;
412 tc->tc_dst = sav->sah->saidx.dst;
413 tc->tc_proto = sav->sah->saidx.proto;
414 tc->tc_protoff = protoff;
415 tc->tc_skip = skip;
416
417 /* Decryption descriptor */
418 if (espx) {
419 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor"));
420 crde->crd_skip = skip + hlen;
421 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
422 crde->crd_inject = skip + hlen - sav->ivlen;
423
424 crde->crd_alg = espx->type;
425 crde->crd_key = sav->key_enc->key_data;
426 crde->crd_klen = _KEYBITS(sav->key_enc);
427 /* XXX Rounds ? */
428 }
429
430 if (mtag == NULL)
431 return crypto_dispatch(crp);
432 else
433 return esp_input_cb(crp);
434 }
435
436 #ifdef INET6
437 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \
438 if (saidx->dst.sa.sa_family == AF_INET6) { \
439 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \
440 } else { \
441 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \
442 } \
443 } while (0)
444 #else
445 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \
446 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag))
447 #endif
448
449 /*
450 * ESP input callback from the crypto driver.
451 */
452 static int
453 esp_input_cb(struct cryptop *crp)
454 {
455 INIT_VNET_IPSEC(curvnet);
456 u_int8_t lastthree[3], aalg[AH_HMAC_HASHLEN];
457 int hlen, skip, protoff, error;
458 struct mbuf *m;
459 struct cryptodesc *crd;
460 struct auth_hash *esph;
461 struct enc_xform *espx;
462 struct tdb_crypto *tc;
463 struct m_tag *mtag;
464 struct secasvar *sav;
465 struct secasindex *saidx;
466 caddr_t ptr;
467
468 crd = crp->crp_desc;
469 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!"));
470
471 tc = (struct tdb_crypto *) crp->crp_opaque;
472 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!"));
473 skip = tc->tc_skip;
474 protoff = tc->tc_protoff;
475 mtag = (struct m_tag *) tc->tc_ptr;
476 m = (struct mbuf *) crp->crp_buf;
477
478 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi);
479 if (sav == NULL) {
480 V_espstat.esps_notdb++;
481 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n",
482 __func__, ipsec_address(&tc->tc_dst),
483 (u_long) ntohl(tc->tc_spi), tc->tc_proto));
484 error = ENOBUFS; /*XXX*/
485 goto bad;
486 }
487
488 saidx = &sav->sah->saidx;
489 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
490 saidx->dst.sa.sa_family == AF_INET6,
491 ("unexpected protocol family %u", saidx->dst.sa.sa_family));
492
493 esph = sav->tdb_authalgxform;
494 espx = sav->tdb_encalgxform;
495
496 /* Check for crypto errors */
497 if (crp->crp_etype) {
498 /* Reset the session ID */
499 if (sav->tdb_cryptoid != 0)
500 sav->tdb_cryptoid = crp->crp_sid;
501
502 if (crp->crp_etype == EAGAIN) {
503 KEY_FREESAV(&sav);
504 error = crypto_dispatch(crp);
505 return error;
506 }
507
508 V_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 V_espstat.esps_crypto++;
517 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
518 error = EINVAL;
519 goto bad;
520 }
521 V_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 V_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 V_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 V_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 V_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 V_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 V_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 return error;
635 bad:
636 if (sav)
637 KEY_FREESAV(&sav);
638 if (m != NULL)
639 m_freem(m);
640 if (tc != NULL)
641 free(tc, M_XDATA);
642 if (crp != NULL)
643 crypto_freereq(crp);
644 return error;
645 }
646
647 /*
648 * ESP output routine, called by ipsec[46]_process_packet().
649 */
650 static int
651 esp_output(
652 struct mbuf *m,
653 struct ipsecrequest *isr,
654 struct mbuf **mp,
655 int skip,
656 int protoff
657 )
658 {
659 INIT_VNET_IPSEC(curvnet);
660 struct enc_xform *espx;
661 struct auth_hash *esph;
662 int hlen, rlen, plen, padding, blks, alen, i, roff;
663 struct mbuf *mo = (struct mbuf *) NULL;
664 struct tdb_crypto *tc;
665 struct secasvar *sav;
666 struct secasindex *saidx;
667 unsigned char *pad;
668 u_int8_t prot;
669 int error, maxpacketsize;
670
671 struct cryptodesc *crde = NULL, *crda = NULL;
672 struct cryptop *crp;
673
674 sav = isr->sav;
675 IPSEC_ASSERT(sav != NULL, ("null SA"));
676 esph = sav->tdb_authalgxform;
677 espx = sav->tdb_encalgxform;
678 IPSEC_ASSERT(espx != NULL, ("null encoding xform"));
679
680 if (sav->flags & SADB_X_EXT_OLD)
681 hlen = sizeof (struct esp) + sav->ivlen;
682 else
683 hlen = sizeof (struct newesp) + sav->ivlen;
684
685 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */
686 /*
687 * NB: The null encoding transform has a blocksize of 4
688 * so that headers are properly aligned.
689 */
690 blks = espx->blocksize; /* IV blocksize */
691
692 /* XXX clamp padding length a la KAME??? */
693 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;
694 plen = rlen + padding; /* Padded payload length. */
695
696 if (esph)
697 alen = AH_HMAC_HASHLEN;
698 else
699 alen = 0;
700
701 V_espstat.esps_output++;
702
703 saidx = &sav->sah->saidx;
704 /* Check for maximum packet size violations. */
705 switch (saidx->dst.sa.sa_family) {
706 #ifdef INET
707 case AF_INET:
708 maxpacketsize = IP_MAXPACKET;
709 break;
710 #endif /* INET */
711 #ifdef INET6
712 case AF_INET6:
713 maxpacketsize = IPV6_MAXPACKET;
714 break;
715 #endif /* INET6 */
716 default:
717 DPRINTF(("%s: unknown/unsupported protocol "
718 "family %d, SA %s/%08lx\n", __func__,
719 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst),
720 (u_long) ntohl(sav->spi)));
721 V_espstat.esps_nopf++;
722 error = EPFNOSUPPORT;
723 goto bad;
724 }
725 if (skip + hlen + rlen + padding + alen > maxpacketsize) {
726 DPRINTF(("%s: packet in SA %s/%08lx got too big "
727 "(len %u, max len %u)\n", __func__,
728 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi),
729 skip + hlen + rlen + padding + alen, maxpacketsize));
730 V_espstat.esps_toobig++;
731 error = EMSGSIZE;
732 goto bad;
733 }
734
735 /* Update the counters. */
736 V_espstat.esps_obytes += m->m_pkthdr.len - skip;
737
738 m = m_unshare(m, M_NOWAIT);
739 if (m == NULL) {
740 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__,
741 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
742 V_espstat.esps_hdrops++;
743 error = ENOBUFS;
744 goto bad;
745 }
746
747 /* Inject ESP header. */
748 mo = m_makespace(m, skip, hlen, &roff);
749 if (mo == NULL) {
750 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n",
751 __func__, hlen, ipsec_address(&saidx->dst),
752 (u_long) ntohl(sav->spi)));
753 V_espstat.esps_hdrops++; /* XXX diffs from openbsd */
754 error = ENOBUFS;
755 goto bad;
756 }
757
758 /* Initialize ESP header. */
759 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t));
760 if (sav->replay) {
761 u_int32_t replay;
762
763 #ifdef REGRESSION
764 /* Emulate replay attack when ipsec_replay is TRUE. */
765 if (!V_ipsec_replay)
766 #endif
767 sav->replay->count++;
768 replay = htonl(sav->replay->count);
769 bcopy((caddr_t) &replay,
770 mtod(mo, caddr_t) + roff + sizeof(u_int32_t),
771 sizeof(u_int32_t));
772 }
773
774 /*
775 * Add padding -- better to do it ourselves than use the crypto engine,
776 * although if/when we support compression, we'd have to do that.
777 */
778 pad = (u_char *) m_pad(m, padding + alen);
779 if (pad == NULL) {
780 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__,
781 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
782 m = NULL; /* NB: free'd by m_pad */
783 error = ENOBUFS;
784 goto bad;
785 }
786
787 /*
788 * Add padding: random, zero, or self-describing.
789 * XXX catch unexpected setting
790 */
791 switch (sav->flags & SADB_X_EXT_PMASK) {
792 case SADB_X_EXT_PRAND:
793 (void) read_random(pad, padding - 2);
794 break;
795 case SADB_X_EXT_PZERO:
796 bzero(pad, padding - 2);
797 break;
798 case SADB_X_EXT_PSEQ:
799 for (i = 0; i < padding - 2; i++)
800 pad[i] = i+1;
801 break;
802 }
803
804 /* Fix padding length and Next Protocol in padding itself. */
805 pad[padding - 2] = padding - 2;
806 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1);
807
808 /* Fix Next Protocol in IPv4/IPv6 header. */
809 prot = IPPROTO_ESP;
810 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot);
811
812 /* Get crypto descriptors. */
813 crp = crypto_getreq(esph && espx ? 2 : 1);
814 if (crp == NULL) {
815 DPRINTF(("%s: failed to acquire crypto descriptors\n",
816 __func__));
817 V_espstat.esps_crypto++;
818 error = ENOBUFS;
819 goto bad;
820 }
821
822 if (espx) {
823 crde = crp->crp_desc;
824 crda = crde->crd_next;
825
826 /* Encryption descriptor. */
827 crde->crd_skip = skip + hlen;
828 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
829 crde->crd_flags = CRD_F_ENCRYPT;
830 crde->crd_inject = skip + hlen - sav->ivlen;
831
832 /* Encryption operation. */
833 crde->crd_alg = espx->type;
834 crde->crd_key = sav->key_enc->key_data;
835 crde->crd_klen = _KEYBITS(sav->key_enc);
836 /* XXX Rounds ? */
837 } else
838 crda = crp->crp_desc;
839
840 /* IPsec-specific opaque crypto info. */
841 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
842 M_XDATA, M_NOWAIT|M_ZERO);
843 if (tc == NULL) {
844 crypto_freereq(crp);
845 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
846 V_espstat.esps_crypto++;
847 error = ENOBUFS;
848 goto bad;
849 }
850
851 /* Callback parameters */
852 tc->tc_isr = isr;
853 tc->tc_spi = sav->spi;
854 tc->tc_dst = saidx->dst;
855 tc->tc_proto = saidx->proto;
856
857 /* Crypto operation descriptor. */
858 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
859 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
860 crp->crp_buf = (caddr_t) m;
861 crp->crp_callback = esp_output_cb;
862 crp->crp_opaque = (caddr_t) tc;
863 crp->crp_sid = sav->tdb_cryptoid;
864
865 if (esph) {
866 /* Authentication descriptor. */
867 crda->crd_skip = skip;
868 crda->crd_len = m->m_pkthdr.len - (skip + alen);
869 crda->crd_inject = m->m_pkthdr.len - alen;
870
871 /* Authentication operation. */
872 crda->crd_alg = esph->type;
873 crda->crd_key = sav->key_auth->key_data;
874 crda->crd_klen = _KEYBITS(sav->key_auth);
875 }
876
877 return crypto_dispatch(crp);
878 bad:
879 if (m)
880 m_freem(m);
881 return (error);
882 }
883
884 /*
885 * ESP output callback from the crypto driver.
886 */
887 static int
888 esp_output_cb(struct cryptop *crp)
889 {
890 INIT_VNET_IPSEC(curvnet);
891 struct tdb_crypto *tc;
892 struct ipsecrequest *isr;
893 struct secasvar *sav;
894 struct mbuf *m;
895 int err, error;
896
897 tc = (struct tdb_crypto *) crp->crp_opaque;
898 IPSEC_ASSERT(tc != NULL, ("null opaque data area!"));
899 m = (struct mbuf *) crp->crp_buf;
900
901 isr = tc->tc_isr;
902 IPSECREQUEST_LOCK(isr);
903 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi);
904 if (sav == NULL) {
905 V_espstat.esps_notdb++;
906 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n",
907 __func__, ipsec_address(&tc->tc_dst),
908 (u_long) ntohl(tc->tc_spi), tc->tc_proto));
909 error = ENOBUFS; /*XXX*/
910 goto bad;
911 }
912 IPSEC_ASSERT(isr->sav == sav,
913 ("SA changed was %p now %p\n", isr->sav, sav));
914
915 /* Check for crypto errors. */
916 if (crp->crp_etype) {
917 /* Reset session ID. */
918 if (sav->tdb_cryptoid != 0)
919 sav->tdb_cryptoid = crp->crp_sid;
920
921 if (crp->crp_etype == EAGAIN) {
922 KEY_FREESAV(&sav);
923 IPSECREQUEST_UNLOCK(isr);
924 error = crypto_dispatch(crp);
925 return error;
926 }
927
928 V_espstat.esps_noxform++;
929 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
930 error = crp->crp_etype;
931 goto bad;
932 }
933
934 /* Shouldn't happen... */
935 if (m == NULL) {
936 V_espstat.esps_crypto++;
937 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
938 error = EINVAL;
939 goto bad;
940 }
941 V_espstat.esps_hist[sav->alg_enc]++;
942 if (sav->tdb_authalgxform != NULL)
943 V_ahstat.ahs_hist[sav->alg_auth]++;
944
945 /* Release crypto descriptors. */
946 free(tc, M_XDATA);
947 crypto_freereq(crp);
948
949 #ifdef REGRESSION
950 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
951 if (V_ipsec_integrity) {
952 static unsigned char ipseczeroes[AH_HMAC_HASHLEN];
953 struct auth_hash *esph;
954
955 /*
956 |