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 #include <net/vnet.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 <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 VNET_DEFINE(int, esp_enable) = 1;
79 VNET_PCPUSTAT_DEFINE(struct espstat, espstat);
80 VNET_PCPUSTAT_SYSINIT(espstat);
81
82 #ifdef VIMAGE
83 VNET_PCPUSTAT_SYSUNINIT(espstat);
84 #endif /* VIMAGE */
85
86 SYSCTL_DECL(_net_inet_esp);
87 SYSCTL_VNET_INT(_net_inet_esp, OID_AUTO,
88 esp_enable, CTLFLAG_RW, &VNET_NAME(esp_enable), 0, "");
89 SYSCTL_VNET_PCPUSTAT(_net_inet_esp, IPSECCTL_STATS, stats,
90 struct espstat, espstat,
91 "ESP statistics (struct espstat, netipsec/esp_var.h");
92
93 static int esp_input_cb(struct cryptop *op);
94 static int esp_output_cb(struct cryptop *crp);
95
96 /*
97 * NB: this is public for use by the PF_KEY support.
98 * NB: if you add support here; be sure to add code to esp_attach below!
99 */
100 struct enc_xform *
esp_algorithm_lookup(int alg)101 esp_algorithm_lookup(int alg)
102 {
103 if (alg >= ESP_ALG_MAX)
104 return NULL;
105 switch (alg) {
106 case SADB_EALG_DESCBC:
107 return &enc_xform_des;
108 case SADB_EALG_3DESCBC:
109 return &enc_xform_3des;
110 case SADB_X_EALG_AES:
111 return &enc_xform_rijndael128;
112 case SADB_X_EALG_BLOWFISHCBC:
113 return &enc_xform_blf;
114 case SADB_X_EALG_CAST128CBC:
115 return &enc_xform_cast5;
116 case SADB_X_EALG_SKIPJACK:
117 return &enc_xform_skipjack;
118 case SADB_EALG_NULL:
119 return &enc_xform_null;
120 case SADB_X_EALG_CAMELLIACBC:
121 return &enc_xform_camellia;
122 }
123 return NULL;
124 }
125
126 size_t
esp_hdrsiz(struct secasvar * sav)127 esp_hdrsiz(struct secasvar *sav)
128 {
129 size_t size;
130
131 if (sav != NULL) {
132 /*XXX not right for null algorithm--does it matter??*/
133 IPSEC_ASSERT(sav->tdb_encalgxform != NULL,
134 ("SA with null xform"));
135 if (sav->flags & SADB_X_EXT_OLD)
136 size = sizeof (struct esp);
137 else
138 size = sizeof (struct newesp);
139 size += sav->tdb_encalgxform->blocksize + 9;
140 /*XXX need alg check???*/
141 if (sav->tdb_authalgxform != NULL && sav->replay)
142 size += ah_hdrsiz(sav);
143 } else {
144 /*
145 * base header size
146 * + max iv length for CBC mode
147 * + max pad length
148 * + sizeof (pad length field)
149 * + sizeof (next header field)
150 * + max icv supported.
151 */
152 size = sizeof (struct newesp) + EALG_MAX_BLOCK_LEN + 9 + 16;
153 }
154 return size;
155 }
156
157 /*
158 * esp_init() is called when an SPI is being set up.
159 */
160 static int
esp_init(struct secasvar * sav,struct xformsw * xsp)161 esp_init(struct secasvar *sav, struct xformsw *xsp)
162 {
163 struct enc_xform *txform;
164 struct cryptoini cria, crie;
165 int keylen;
166 int error;
167
168 txform = esp_algorithm_lookup(sav->alg_enc);
169 if (txform == NULL) {
170 DPRINTF(("%s: unsupported encryption algorithm %d\n",
171 __func__, sav->alg_enc));
172 return EINVAL;
173 }
174 if (sav->key_enc == NULL) {
175 DPRINTF(("%s: no encoding key for %s algorithm\n",
176 __func__, txform->name));
177 return EINVAL;
178 }
179 if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) {
180 DPRINTF(("%s: 4-byte IV not supported with protocol\n",
181 __func__));
182 return EINVAL;
183 }
184 keylen = _KEYLEN(sav->key_enc);
185 if (txform->minkey > keylen || keylen > txform->maxkey) {
186 DPRINTF(("%s: invalid key length %u, must be in the range "
187 "[%u..%u] for algorithm %s\n", __func__,
188 keylen, txform->minkey, txform->maxkey,
189 txform->name));
190 return EINVAL;
191 }
192
193 /*
194 * NB: The null xform needs a non-zero blocksize to keep the
195 * crypto code happy but if we use it to set ivlen then
196 * the ESP header will be processed incorrectly. The
197 * compromise is to force it to zero here.
198 */
199 sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize);
200 sav->iv = (caddr_t) malloc(sav->ivlen, M_XDATA, M_WAITOK);
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, V_crypto_support);
228 } else if (sav->tdb_encalgxform) {
229 error = crypto_newsession(&sav->tdb_cryptoid,
230 &crie, V_crypto_support);
231 } else if (sav->tdb_authalgxform) {
232 error = crypto_newsession(&sav->tdb_cryptoid,
233 &cria, V_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
esp_zeroize(struct secasvar * sav)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
esp_input(struct mbuf * m,struct secasvar * sav,int skip,int protoff)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_ASSERT(sav != NULL, ("null SA"));
281 IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform"));
282
283 /* Valid IP Packet length ? */
284 if ( (skip&3) || (m->m_pkthdr.len&3) ){
285 DPRINTF(("%s: misaligned packet, skip %u pkt len %u",
286 __func__, skip, m->m_pkthdr.len));
287 ESPSTAT_INC(esps_badilen);
288 m_freem(m);
289 return EINVAL;
290 }
291
292 /* XXX don't pullup, just copy header */
293 IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp));
294
295 esph = sav->tdb_authalgxform;
296 espx = sav->tdb_encalgxform;
297
298 /* Determine the ESP header length */
299 if (sav->flags & SADB_X_EXT_OLD)
300 hlen = sizeof (struct esp) + sav->ivlen;
301 else
302 hlen = sizeof (struct newesp) + sav->ivlen;
303 /* Authenticator hash size */
304 if (esph != NULL) {
305 switch (esph->type) {
306 case CRYPTO_SHA2_256_HMAC:
307 case CRYPTO_SHA2_384_HMAC:
308 case CRYPTO_SHA2_512_HMAC:
309 alen = esph->hashsize/2;
310 break;
311 default:
312 alen = AH_HMAC_HASHLEN;
313 break;
314 }
315 }else
316 alen = 0;
317
318 /*
319 * Verify payload length is multiple of encryption algorithm
320 * block size.
321 *
322 * NB: This works for the null algorithm because the blocksize
323 * is 4 and all packets must be 4-byte aligned regardless
324 * of the algorithm.
325 */
326 plen = m->m_pkthdr.len - (skip + hlen + alen);
327 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) {
328 DPRINTF(("%s: payload of %d octets not a multiple of %d octets,"
329 " SA %s/%08lx\n", __func__,
330 plen, espx->blocksize,
331 ipsec_address(&sav->sah->saidx.dst),
332 (u_long) ntohl(sav->spi)));
333 ESPSTAT_INC(esps_badilen);
334 m_freem(m);
335 return EINVAL;
336 }
337
338 /*
339 * Check sequence number.
340 */
341 if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) {
342 DPRINTF(("%s: packet replay check for %s\n", __func__,
343 ipsec_logsastr(sav))); /*XXX*/
344 ESPSTAT_INC(esps_replay);
345 m_freem(m);
346 return ENOBUFS; /*XXX*/
347 }
348
349 /* Update the counters */
350 ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen));
351
352 /* Find out if we've already done crypto */
353 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL);
354 mtag != NULL;
355 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) {
356 tdbi = (struct tdb_ident *) (mtag + 1);
357 if (tdbi->proto == sav->sah->saidx.proto &&
358 tdbi->spi == sav->spi &&
359 !bcmp(&tdbi->dst, &sav->sah->saidx.dst,
360 sizeof(union sockaddr_union)))
361 break;
362 }
363
364 /* Get crypto descriptors */
365 crp = crypto_getreq(esph && espx ? 2 : 1);
366 if (crp == NULL) {
367 DPRINTF(("%s: failed to acquire crypto descriptors\n",
368 __func__));
369 ESPSTAT_INC(esps_crypto);
370 m_freem(m);
371 return ENOBUFS;
372 }
373
374 /* Get IPsec-specific opaque pointer */
375 if (esph == NULL || mtag != NULL)
376 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
377 M_XDATA, M_NOWAIT|M_ZERO);
378 else
379 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen,
380 M_XDATA, M_NOWAIT|M_ZERO);
381 if (tc == NULL) {
382 crypto_freereq(crp);
383 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
384 ESPSTAT_INC(esps_crypto);
385 m_freem(m);
386 return ENOBUFS;
387 }
388
389 tc->tc_ptr = (caddr_t) mtag;
390
391 if (esph) {
392 struct cryptodesc *crda = crp->crp_desc;
393
394 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor"));
395
396 /* Authentication descriptor */
397 crda->crd_skip = skip;
398 crda->crd_len = m->m_pkthdr.len - (skip + alen);
399 crda->crd_inject = m->m_pkthdr.len - alen;
400
401 crda->crd_alg = esph->type;
402 crda->crd_key = sav->key_auth->key_data;
403 crda->crd_klen = _KEYBITS(sav->key_auth);
404
405 /* Copy the authenticator */
406 if (mtag == NULL)
407 m_copydata(m, m->m_pkthdr.len - alen, alen,
408 (caddr_t) (tc + 1));
409
410 /* Chain authentication request */
411 crde = crda->crd_next;
412 } else {
413 crde = crp->crp_desc;
414 }
415
416 /* Crypto operation descriptor */
417 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */
418 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
419 crp->crp_buf = (caddr_t) m;
420 crp->crp_callback = esp_input_cb;
421 crp->crp_sid = sav->tdb_cryptoid;
422 crp->crp_opaque = (caddr_t) tc;
423
424 /* These are passed as-is to the callback */
425 tc->tc_spi = sav->spi;
426 tc->tc_dst = sav->sah->saidx.dst;
427 tc->tc_proto = sav->sah->saidx.proto;
428 tc->tc_protoff = protoff;
429 tc->tc_skip = skip;
430 KEY_ADDREFSA(sav);
431 tc->tc_sav = sav;
432
433 /* Decryption descriptor */
434 if (espx) {
435 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor"));
436 crde->crd_skip = skip + hlen;
437 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
438 crde->crd_inject = skip + hlen - sav->ivlen;
439
440 crde->crd_alg = espx->type;
441 crde->crd_key = sav->key_enc->key_data;
442 crde->crd_klen = _KEYBITS(sav->key_enc);
443 /* XXX Rounds ? */
444 }
445
446 if (mtag == NULL)
447 return crypto_dispatch(crp);
448 else
449 return esp_input_cb(crp);
450 }
451
452 /*
453 * ESP input callback from the crypto driver.
454 */
455 static int
esp_input_cb(struct cryptop * crp)456 esp_input_cb(struct cryptop *crp)
457 {
458 u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN];
459 int hlen, skip, protoff, error, alen;
460 struct mbuf *m;
461 struct cryptodesc *crd;
462 struct auth_hash *esph;
463 struct enc_xform *espx;
464 struct tdb_crypto *tc;
465 struct m_tag *mtag;
466 struct secasvar *sav;
467 struct secasindex *saidx;
468 caddr_t ptr;
469
470 crd = crp->crp_desc;
471 IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!"));
472
473 tc = (struct tdb_crypto *) crp->crp_opaque;
474 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!"));
475 skip = tc->tc_skip;
476 protoff = tc->tc_protoff;
477 mtag = (struct m_tag *) tc->tc_ptr;
478 m = (struct mbuf *) crp->crp_buf;
479
480 sav = tc->tc_sav;
481 IPSEC_ASSERT(sav != NULL, ("null SA!"));
482
483 saidx = &sav->sah->saidx;
484 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
485 saidx->dst.sa.sa_family == AF_INET6,
486 ("unexpected protocol family %u", saidx->dst.sa.sa_family));
487
488 esph = sav->tdb_authalgxform;
489 espx = sav->tdb_encalgxform;
490
491 /* Check for crypto errors */
492 if (crp->crp_etype) {
493 /* Reset the session ID */
494 if (sav->tdb_cryptoid != 0)
495 sav->tdb_cryptoid = crp->crp_sid;
496
497 if (crp->crp_etype == EAGAIN)
498 return (crypto_dispatch(crp));
499
500 ESPSTAT_INC(esps_noxform);
501 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
502 error = crp->crp_etype;
503 goto bad;
504 }
505
506 /* Shouldn't happen... */
507 if (m == NULL) {
508 ESPSTAT_INC(esps_crypto);
509 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
510 error = EINVAL;
511 goto bad;
512 }
513 ESPSTAT_INC(esps_hist[sav->alg_enc]);
514
515 /* If authentication was performed, check now. */
516 if (esph != NULL) {
517 switch (esph->type) {
518 case CRYPTO_SHA2_256_HMAC:
519 case CRYPTO_SHA2_384_HMAC:
520 case CRYPTO_SHA2_512_HMAC:
521 alen = esph->hashsize/2;
522 break;
523 default:
524 alen = AH_HMAC_HASHLEN;
525 break;
526 }
527 /*
528 * If we have a tag, it means an IPsec-aware NIC did
529 * the verification for us. Otherwise we need to
530 * check the authentication calculation.
531 */
532 AHSTAT_INC(ahs_hist[sav->alg_auth]);
533 if (mtag == NULL) {
534 /* Copy the authenticator from the packet */
535 m_copydata(m, m->m_pkthdr.len - alen,
536 alen, aalg);
537
538 ptr = (caddr_t) (tc + 1);
539
540 /* Verify authenticator */
541 if (bcmp(ptr, aalg, alen) != 0) {
542 DPRINTF(("%s: "
543 "authentication hash mismatch for packet in SA %s/%08lx\n",
544 __func__,
545 ipsec_address(&saidx->dst),
546 (u_long) ntohl(sav->spi)));
547 ESPSTAT_INC(esps_badauth);
548 error = EACCES;
549 goto bad;
550 }
551 }
552
553 /* Remove trailing authenticator */
554 m_adj(m, -alen);
555 }
556
557 /* Release the crypto descriptors */
558 free(tc, M_XDATA), tc = NULL;
559 crypto_freereq(crp), crp = NULL;
560
561 /*
562 * Packet is now decrypted.
563 */
564 m->m_flags |= M_DECRYPTED;
565
566 /*
567 * Update replay sequence number, if appropriate.
568 */
569 if (sav->replay) {
570 u_int32_t seq;
571
572 m_copydata(m, skip + offsetof(struct newesp, esp_seq),
573 sizeof (seq), (caddr_t) &seq);
574 if (ipsec_updatereplay(ntohl(seq), sav)) {
575 DPRINTF(("%s: packet replay check for %s\n", __func__,
576 ipsec_logsastr(sav)));
577 ESPSTAT_INC(esps_replay);
578 error = ENOBUFS;
579 goto bad;
580 }
581 }
582
583 /* Determine the ESP header length */
584 if (sav->flags & SADB_X_EXT_OLD)
585 hlen = sizeof (struct esp) + sav->ivlen;
586 else
587 hlen = sizeof (struct newesp) + sav->ivlen;
588
589 /* Remove the ESP header and IV from the mbuf. */
590 error = m_striphdr(m, skip, hlen);
591 if (error) {
592 ESPSTAT_INC(esps_hdrops);
593 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__,
594 ipsec_address(&sav->sah->saidx.dst),
595 (u_long) ntohl(sav->spi)));
596 goto bad;
597 }
598
599 /* Save the last three bytes of decrypted data */
600 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree);
601
602 /* Verify pad length */
603 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) {
604 ESPSTAT_INC(esps_badilen);
605 DPRINTF(("%s: invalid padding length %d for %u byte packet "
606 "in SA %s/%08lx\n", __func__,
607 lastthree[1], m->m_pkthdr.len - skip,
608 ipsec_address(&sav->sah->saidx.dst),
609 (u_long) ntohl(sav->spi)));
610 error = EINVAL;
611 goto bad;
612 }
613
614 /* Verify correct decryption by checking the last padding bytes */
615 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) {
616 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) {
617 ESPSTAT_INC(esps_badenc);
618 DPRINTF(("%s: decryption failed for packet in "
619 "SA %s/%08lx\n", __func__,
620 ipsec_address(&sav->sah->saidx.dst),
621 (u_long) ntohl(sav->spi)));
622 error = EINVAL;
623 goto bad;
624 }
625 }
626
627 /* Trim the mbuf chain to remove trailing authenticator and padding */
628 m_adj(m, -(lastthree[1] + 2));
629
630 /* Restore the Next Protocol field */
631 m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2);
632
633 switch (saidx->dst.sa.sa_family) {
634 #ifdef INET6
635 case AF_INET6:
636 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag);
637 break;
638 #endif
639 #ifdef INET
640 case AF_INET:
641 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag);
642 break;
643 #endif
644 default:
645 panic("%s: Unexpected address family: %d saidx=%p", __func__,
646 saidx->dst.sa.sa_family, saidx);
647 }
648
649 KEY_FREESAV(&sav);
650 return error;
651 bad:
652 if (sav)
653 KEY_FREESAV(&sav);
654 if (m != NULL)
655 m_freem(m);
656 if (tc != NULL)
657 free(tc, M_XDATA);
658 if (crp != NULL)
659 crypto_freereq(crp);
660 return error;
661 }
662
663 /*
664 * ESP output routine, called by ipsec[46]_process_packet().
665 */
666 static int
esp_output(struct mbuf * m,struct ipsecrequest * isr,struct mbuf ** mp,int skip,int protoff)667 esp_output(
668 struct mbuf *m,
669 struct ipsecrequest *isr,
670 struct mbuf **mp,
671 int skip,
672 int protoff
673 )
674 {
675 struct enc_xform *espx;
676 struct auth_hash *esph;
677 int hlen, rlen, padding, blks, alen, i, roff;
678 struct mbuf *mo = (struct mbuf *) NULL;
679 struct tdb_crypto *tc;
680 struct secasvar *sav;
681 struct secasindex *saidx;
682 unsigned char *pad;
683 u_int8_t prot;
684 int error, maxpacketsize;
685
686 struct cryptodesc *crde = NULL, *crda = NULL;
687 struct cryptop *crp;
688
689 sav = isr->sav;
690 IPSEC_ASSERT(sav != NULL, ("null SA"));
691 esph = sav->tdb_authalgxform;
692 espx = sav->tdb_encalgxform;
693 IPSEC_ASSERT(espx != NULL, ("null encoding xform"));
694
695 if (sav->flags & SADB_X_EXT_OLD)
696 hlen = sizeof (struct esp) + sav->ivlen;
697 else
698 hlen = sizeof (struct newesp) + sav->ivlen;
699
700 rlen = m->m_pkthdr.len - skip; /* Raw payload length. */
701 /*
702 * NB: The null encoding transform has a blocksize of 4
703 * so that headers are properly aligned.
704 */
705 blks = espx->blocksize; /* IV blocksize */
706
707 /* XXX clamp padding length a la KAME??? */
708 padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;
709
710 if (esph)
711 switch (esph->type) {
712 case CRYPTO_SHA2_256_HMAC:
713 case CRYPTO_SHA2_384_HMAC:
714 case CRYPTO_SHA2_512_HMAC:
715 alen = esph->hashsize/2;
716 break;
717 default:
718 alen = AH_HMAC_HASHLEN;
719 break;
720 }
721 else
722 alen = 0;
723
724 ESPSTAT_INC(esps_output);
725
726 saidx = &sav->sah->saidx;
727 /* Check for maximum packet size violations. */
728 switch (saidx->dst.sa.sa_family) {
729 #ifdef INET
730 case AF_INET:
731 maxpacketsize = IP_MAXPACKET;
732 break;
733 #endif /* INET */
734 #ifdef INET6
735 case AF_INET6:
736 maxpacketsize = IPV6_MAXPACKET;
737 break;
738 #endif /* INET6 */
739 default:
740 DPRINTF(("%s: unknown/unsupported protocol "
741 "family %d, SA %s/%08lx\n", __func__,
742 saidx->dst.sa.sa_family, ipsec_address(&saidx->dst),
743 (u_long) ntohl(sav->spi)));
744 ESPSTAT_INC(esps_nopf);
745 error = EPFNOSUPPORT;
746 goto bad;
747 }
748 if (skip + hlen + rlen + padding + alen > maxpacketsize) {
749 DPRINTF(("%s: packet in SA %s/%08lx got too big "
750 "(len %u, max len %u)\n", __func__,
751 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi),
752 skip + hlen + rlen + padding + alen, maxpacketsize));
753 ESPSTAT_INC(esps_toobig);
754 error = EMSGSIZE;
755 goto bad;
756 }
757
758 /* Update the counters. */
759 ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip);
760
761 m = m_unshare(m, M_NOWAIT);
762 if (m == NULL) {
763 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__,
764 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
765 ESPSTAT_INC(esps_hdrops);
766 error = ENOBUFS;
767 goto bad;
768 }
769
770 /* Inject ESP header. */
771 mo = m_makespace(m, skip, hlen, &roff);
772 if (mo == NULL) {
773 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n",
774 __func__, hlen, ipsec_address(&saidx->dst),
775 (u_long) ntohl(sav->spi)));
776 ESPSTAT_INC(esps_hdrops); /* XXX diffs from openbsd */
777 error = ENOBUFS;
778 goto bad;
779 }
780
781 /* Initialize ESP header. */
782 bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t));
783 if (sav->replay) {
784 u_int32_t replay;
785
786 #ifdef REGRESSION
787 /* Emulate replay attack when ipsec_replay is TRUE. */
788 if (!V_ipsec_replay)
789 #endif
790 sav->replay->count++;
791 replay = htonl(sav->replay->count);
792 bcopy((caddr_t) &replay,
793 mtod(mo, caddr_t) + roff + sizeof(u_int32_t),
794 sizeof(u_int32_t));
795 }
796
797 /*
798 * Add padding -- better to do it ourselves than use the crypto engine,
799 * although if/when we support compression, we'd have to do that.
800 */
801 pad = (u_char *) m_pad(m, padding + alen);
802 if (pad == NULL) {
803 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__,
804 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
805 m = NULL; /* NB: free'd by m_pad */
806 error = ENOBUFS;
807 goto bad;
808 }
809
810 /*
811 * Add padding: random, zero, or self-describing.
812 * XXX catch unexpected setting
813 */
814 switch (sav->flags & SADB_X_EXT_PMASK) {
815 case SADB_X_EXT_PRAND:
816 (void) read_random(pad, padding - 2);
817 break;
818 case SADB_X_EXT_PZERO:
819 bzero(pad, padding - 2);
820 break;
821 case SADB_X_EXT_PSEQ:
822 for (i = 0; i < padding - 2; i++)
823 pad[i] = i+1;
824 break;
825 }
826
827 /* Fix padding length and Next Protocol in padding itself. */
828 pad[padding - 2] = padding - 2;
829 m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1);
830
831 /* Fix Next Protocol in IPv4/IPv6 header. */
832 prot = IPPROTO_ESP;
833 m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot);
834
835 /* Get crypto descriptors. */
836 crp = crypto_getreq(esph && espx ? 2 : 1);
837 if (crp == NULL) {
838 DPRINTF(("%s: failed to acquire crypto descriptors\n",
839 __func__));
840 ESPSTAT_INC(esps_crypto);
841 error = ENOBUFS;
842 goto bad;
843 }
844
845 if (espx) {
846 crde = crp->crp_desc;
847 crda = crde->crd_next;
848
849 /* Encryption descriptor. */
850 crde->crd_skip = skip + hlen;
851 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
852 crde->crd_flags = CRD_F_ENCRYPT;
853 crde->crd_inject = skip + hlen - sav->ivlen;
854
855 /* Encryption operation. */
856 crde->crd_alg = espx->type;
857 crde->crd_key = sav->key_enc->key_data;
858 crde->crd_klen = _KEYBITS(sav->key_enc);
859 /* XXX Rounds ? */
860 } else
861 crda = crp->crp_desc;
862
863 /* IPsec-specific opaque crypto info. */
864 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
865 M_XDATA, M_NOWAIT|M_ZERO);
866 if (tc == NULL) {
867 crypto_freereq(crp);
868 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
869 ESPSTAT_INC(esps_crypto);
870 error = ENOBUFS;
871 goto bad;
872 }
873
874 /* Callback parameters */
875 tc->tc_isr = isr;
876 KEY_ADDREFSA(sav);
877 tc->tc_sav = sav;
878 tc->tc_spi = sav->spi;
879 tc->tc_dst = saidx->dst;
880 tc->tc_proto = saidx->proto;
881
882 /* Crypto operation descriptor. */
883 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
884 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
885 crp->crp_buf = (caddr_t) m;
886 crp->crp_callback = esp_output_cb;
887 crp->crp_opaque = (caddr_t) tc;
888 crp->crp_sid = sav->tdb_cryptoid;
889
890 if (esph) {
891 /* Authentication descriptor. */
892 crda->crd_skip = skip;
893 crda->crd_len = m->m_pkthdr.len - (skip + alen);
894 crda->crd_inject = m->m_pkthdr.len - alen;
895
896 /* Authentication operation. */
897 crda->crd_alg = esph->type;
898 crda->crd_key = sav->key_auth->key_data;
899 crda->crd_klen = _KEYBITS(sav->key_auth);
900 }
901
902 return crypto_dispatch(crp);
903 bad:
904 if (m)
905 m_freem(m);
906 return (error);
907 }
908
909 /*
910 * ESP output callback from the crypto driver.
911 */
912 static int
esp_output_cb(struct cryptop * crp)913 esp_output_cb(struct cryptop *crp)
914 {
915 struct tdb_crypto *tc;
916 struct ipsecrequest *isr;
917 struct secasvar *sav;
918 struct mbuf *m;
919 int error;
920
921 tc = (struct tdb_crypto *) crp->crp_opaque;
922 IPSEC_ASSERT(tc != NULL, ("null opaque data area!"));
923 m = (struct mbuf *) crp->crp_buf;
924
925 isr = tc->tc_isr;
926 IPSECREQUEST_LOCK(isr);
927 sav = tc->tc_sav;
928 /* With the isr lock released SA pointer can be updated. */
929 if (sav != isr->sav) {
930 ESPSTAT_INC(esps_notdb);
931 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n",
932 __func__, ipsec_address(&tc->tc_dst),
933 (u_long) ntohl(tc->tc_spi), tc->tc_proto));
934 error = ENOBUFS; /*XXX*/
935 goto bad;
936 }
937
938 /* Check for crypto errors. */
939 if (crp->crp_etype) {
940 /* Reset session ID. */
941 if (sav->tdb_cryptoid != 0)
942 sav->tdb_cryptoid = crp->crp_sid;
943
944 if (crp->crp_etype == EAGAIN) {
945 IPSECREQUEST_UNLOCK(isr);
946 return (crypto_dispatch(crp));
947 }
948
949 ESPSTAT_INC(esps_noxform);
950 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
951 error = crp->crp_etype;
952 goto bad;
953 }
954
955 /* Shouldn't happen... */
956 if (m == NULL) {
957 ESPSTAT_INC(esps_crypto);
958 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
959 error = EINVAL;
960 goto bad;
961 }
962 ESPSTAT_INC(esps_hist[sav->alg_enc]);
963 if (sav->tdb_authalgxform != NULL)
964 AHSTAT_INC(ahs_hist[sav->alg_auth]);
965
966 /* Release crypto descriptors. */
967 free(tc, M_XDATA);
968 crypto_freereq(crp);
969
970 #ifdef REGRESSION
971 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
972 if (V_ipsec_integrity) {
973 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN];
974 struct auth_hash *esph;
975
976 /*
977 * Corrupt HMAC if we want to test integrity verification of
978 * the other side.
979 */
980 esph = sav->tdb_authalgxform;
981 if (esph != NULL) {
982 int alen;
983
984 switch (esph->type) {
985 case CRYPTO_SHA2_256_HMAC:
986 case CRYPTO_SHA2_384_HMAC:
987 case CRYPTO_SHA2_512_HMAC:
988 alen = esph->hashsize/2;
989 break;
990 default:
991 alen = AH_HMAC_HASHLEN;
992 break;
993 }
994 m_copyback(m, m->m_pkthdr.len - alen,
995 alen, ipseczeroes);
996 }
997 }
998 #endif
999
1000 /* NB: m is reclaimed by ipsec_process_done. */
1001 error = ipsec_process_done(m, isr);
1002 KEY_FREESAV(&sav);
1003 IPSECREQUEST_UNLOCK(isr);
1004 return error;
1005 bad:
1006 if (sav)
1007 KEY_FREESAV(&sav);
1008 IPSECREQUEST_UNLOCK(isr);
1009 if (m)
1010 m_freem(m);
1011 free(tc, M_XDATA);
1012 crypto_freereq(crp);
1013 return error;
1014 }
1015
1016 static struct xformsw esp_xformsw = {
1017 XF_ESP, XFT_CONF|XFT_AUTH, "IPsec ESP",
1018 esp_init, esp_zeroize, esp_input,
1019 esp_output
1020 };
1021
1022 static void
esp_attach(void)1023 esp_attach(void)
1024 {
1025
1026 xform_register(&esp_xformsw);
1027 }
1028 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL);
1029