1 /* $NetBSD: xform_esp.c,v 1.107 2024/07/05 04:31:54 rin Exp $ */
2 /* $FreeBSD: xform_esp.c,v 1.2.2.1 2003/01/24 05:11:36 sam Exp $ */
3 /* $OpenBSD: ip_esp.c,v 1.69 2001/06/26 06:18:59 angelos Exp $ */
4
5 /*
6 * The authors of this code are John Ioannidis (ji@tla.org),
7 * Angelos D. Keromytis (kermit@csd.uch.gr) and
8 * Niels Provos (provos@physnet.uni-hamburg.de).
9 *
10 * The original version of this code was written by John Ioannidis
11 * for BSD/OS in Athens, Greece, in November 1995.
12 *
13 * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
14 * by Angelos D. Keromytis.
15 *
16 * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
17 * and Niels Provos.
18 *
19 * Additional features in 1999 by Angelos D. Keromytis.
20 *
21 * Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
22 * Angelos D. Keromytis and Niels Provos.
23 * Copyright (c) 2001 Angelos D. Keromytis.
24 *
25 * Permission to use, copy, and modify this software with or without fee
26 * is hereby granted, provided that this entire notice is included in
27 * all copies of any software which is or includes a copy or
28 * modification of this software.
29 * You may use this code under the GNU public license if you so wish. Please
30 * contribute changes back to the authors under this freer than GPL license
31 * so that we may further the use of strong encryption without limitations to
32 * all.
33 *
34 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
35 * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
36 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
37 * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
38 * PURPOSE.
39 */
40
41 #include <sys/cdefs.h>
42 __KERNEL_RCSID(0, "$NetBSD: xform_esp.c,v 1.107 2024/07/05 04:31:54 rin Exp $");
43
44 #if defined(_KERNEL_OPT)
45 #include "opt_inet.h"
46 #include "opt_ipsec.h"
47 #endif
48
49 #include <sys/param.h>
50 #include <sys/systm.h>
51 #include <sys/mbuf.h>
52 #include <sys/socket.h>
53 #include <sys/syslog.h>
54 #include <sys/kernel.h>
55 #include <sys/sysctl.h>
56 #include <sys/cprng.h>
57 #include <sys/pool.h>
58 #include <sys/pserialize.h>
59
60 #include <net/if.h>
61
62 #include <netinet/in.h>
63 #include <netinet/in_systm.h>
64 #include <netinet/ip.h>
65 #include <netinet/ip_ecn.h>
66 #include <netinet/ip6.h>
67
68 #include <net/route.h>
69 #include <netipsec/ipsec.h>
70 #include <netipsec/ipsec_private.h>
71 #include <netipsec/ah.h>
72 #include <netipsec/ah_var.h>
73 #include <netipsec/esp.h>
74 #include <netipsec/esp_var.h>
75 #include <netipsec/xform.h>
76
77 #ifdef INET6
78 #include <netinet6/ip6_var.h>
79 #include <netipsec/ipsec6.h>
80 #endif
81
82 #include <netipsec/key.h>
83 #include <netipsec/key_debug.h>
84
85 #include <opencrypto/cryptodev.h>
86
87 percpu_t *espstat_percpu;
88
89 int esp_enable = 1;
90
91 static int esp_max_ivlen; /* max iv length over all algorithms */
92
93 static void esp_input_cb(struct cryptop *op);
94 static void esp_output_cb(struct cryptop *crp);
95
96 const uint8_t esp_stats[256] = { SADB_EALG_STATS_INIT };
97
98 static pool_cache_t esp_tdb_crypto_pool_cache;
99 static size_t esp_pool_item_size;
100
101 /*
102 * NB: this is public for use by the PF_KEY support.
103 * NB: if you add support here; be sure to add code to esp_attach below!
104 */
105 const struct enc_xform *
esp_algorithm_lookup(int alg)106 esp_algorithm_lookup(int alg)
107 {
108
109 switch (alg) {
110 case SADB_EALG_DESCBC:
111 return &enc_xform_des;
112 case SADB_EALG_3DESCBC:
113 return &enc_xform_3des;
114 case SADB_X_EALG_AES:
115 return &enc_xform_aes;
116 case SADB_X_EALG_BLOWFISHCBC:
117 return &enc_xform_blf;
118 case SADB_X_EALG_CAST128CBC:
119 return &enc_xform_cast5;
120 case SADB_X_EALG_SKIPJACK:
121 return &enc_xform_skipjack;
122 case SADB_X_EALG_CAMELLIACBC:
123 return &enc_xform_camellia;
124 case SADB_X_EALG_AESCTR:
125 return &enc_xform_aes_ctr;
126 case SADB_X_EALG_AESGCM16:
127 return &enc_xform_aes_gcm;
128 case SADB_X_EALG_AESGMAC:
129 return &enc_xform_aes_gmac;
130 case SADB_EALG_NULL:
131 return &enc_xform_null;
132 }
133 return NULL;
134 }
135
136 size_t
esp_hdrsiz(const struct secasvar * sav)137 esp_hdrsiz(const struct secasvar *sav)
138 {
139 size_t size;
140
141 if (sav != NULL) {
142 /*XXX not right for null algorithm--does it matter??*/
143 KASSERT(sav->tdb_encalgxform != NULL);
144
145 /*
146 * base header size
147 * + iv length for CBC mode
148 * + max pad length
149 * + sizeof(esp trailer)
150 * + icv length (if any).
151 */
152 if (sav->flags & SADB_X_EXT_OLD)
153 size = sizeof(struct esp);
154 else
155 size = sizeof(struct newesp);
156 size += sav->tdb_encalgxform->ivsize + 9 +
157 sizeof(struct esptail);
158
159 /*XXX need alg check???*/
160 if (sav->tdb_authalgxform != NULL && sav->replay)
161 size += ah_authsiz(sav);
162 } else {
163 /*
164 * base header size
165 * + max iv length for CBC mode
166 * + max pad length
167 * + sizeof(esp trailer)
168 * + max icv supported.
169 */
170 size = sizeof(struct newesp) + esp_max_ivlen + 9 +
171 sizeof(struct esptail) + ah_authsiz(NULL);
172 }
173 return size;
174 }
175
176 /*
177 * esp_init() is called when an SPI is being set up.
178 */
179 static int
esp_init(struct secasvar * sav,const struct xformsw * xsp)180 esp_init(struct secasvar *sav, const struct xformsw *xsp)
181 {
182 const struct enc_xform *txform;
183 struct cryptoini cria, crie, *cr;
184 int keylen;
185 int error;
186
187 txform = esp_algorithm_lookup(sav->alg_enc);
188 if (txform == NULL) {
189 DPRINTF("unsupported encryption algorithm %d\n",
190 sav->alg_enc);
191 return EINVAL;
192 }
193 if (sav->key_enc == NULL) {
194 DPRINTF("no encoding key for %s algorithm\n",
195 txform->name);
196 return EINVAL;
197 }
198 if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) {
199 DPRINTF("4-byte IV not supported with protocol\n");
200 return EINVAL;
201 }
202 keylen = _KEYLEN(sav->key_enc);
203 if (txform->minkey > keylen || keylen > txform->maxkey) {
204 DPRINTF("invalid key length %u, must be in "
205 "the range [%u..%u] for algorithm %s\n",
206 keylen, txform->minkey, txform->maxkey, txform->name);
207 return EINVAL;
208 }
209
210 sav->ivlen = txform->ivsize;
211
212 /*
213 * Setup AH-related state.
214 */
215 if (sav->alg_auth != 0) {
216 error = ah_init0(sav, xsp, &cria);
217 if (error)
218 return error;
219 }
220
221 /* NB: override anything set in ah_init0 */
222 sav->tdb_xform = xsp;
223 sav->tdb_encalgxform = txform;
224
225 switch (sav->alg_enc) {
226 case SADB_X_EALG_AESGCM16:
227 case SADB_X_EALG_AESGMAC:
228 switch (keylen) {
229 case 20:
230 sav->alg_auth = SADB_X_AALG_AES128GMAC;
231 sav->tdb_authalgxform = &auth_hash_gmac_aes_128;
232 break;
233 case 28:
234 sav->alg_auth = SADB_X_AALG_AES192GMAC;
235 sav->tdb_authalgxform = &auth_hash_gmac_aes_192;
236 break;
237 case 36:
238 sav->alg_auth = SADB_X_AALG_AES256GMAC;
239 sav->tdb_authalgxform = &auth_hash_gmac_aes_256;
240 break;
241 default:
242 DPRINTF("invalid key length %u, must be either of "
243 "20, 28 or 36\n", keylen);
244 return EINVAL;
245 }
246
247 memset(&cria, 0, sizeof(cria));
248 cria.cri_alg = sav->tdb_authalgxform->type;
249 cria.cri_klen = _KEYBITS(sav->key_enc);
250 cria.cri_key = _KEYBUF(sav->key_enc);
251 break;
252 default:
253 break;
254 }
255
256 /* Initialize crypto session. */
257 memset(&crie, 0, sizeof(crie));
258 crie.cri_alg = sav->tdb_encalgxform->type;
259 crie.cri_klen = _KEYBITS(sav->key_enc);
260 crie.cri_key = _KEYBUF(sav->key_enc);
261 /* XXX Rounds ? */
262
263 if (sav->tdb_authalgxform && sav->tdb_encalgxform) {
264 /* init both auth & enc */
265 crie.cri_next = &cria;
266 cr = &crie;
267 } else if (sav->tdb_encalgxform) {
268 cr = &crie;
269 } else if (sav->tdb_authalgxform) {
270 cr = &cria;
271 } else {
272 /* XXX cannot happen? */
273 DPRINTF("no encoding OR authentication xform!\n");
274 return EINVAL;
275 }
276
277 return crypto_newsession(&sav->tdb_cryptoid, cr, crypto_support);
278 }
279
280 /*
281 * Paranoia.
282 */
283 static void
esp_zeroize(struct secasvar * sav)284 esp_zeroize(struct secasvar *sav)
285 {
286 /* NB: ah_zerorize free's the crypto session state */
287 ah_zeroize(sav);
288
289 if (sav->key_enc) {
290 explicit_memset(_KEYBUF(sav->key_enc), 0,
291 _KEYLEN(sav->key_enc));
292 }
293 sav->tdb_encalgxform = NULL;
294 sav->tdb_xform = NULL;
295 }
296
297 /*
298 * ESP input processing, called (eventually) through the protocol switch.
299 */
300 static int
esp_input(struct mbuf * m,struct secasvar * sav,int skip,int protoff)301 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
302 {
303 const struct auth_hash *esph;
304 const struct enc_xform *espx;
305 struct tdb_crypto *tc;
306 int plen, alen, hlen, error, stat = ESP_STAT_CRYPTO;
307 struct newesp *esp;
308 struct cryptodesc *crde;
309 struct cryptop *crp;
310
311 KASSERT(sav != NULL);
312 KASSERT(sav->tdb_encalgxform != NULL);
313 if (__predict_false((skip & 3) != 0 || (m->m_pkthdr.len & 3) != 0)) {
314 DPRINTF("%s: misaligned packet, skip %u pkt len %u", __func__,
315 skip, m->m_pkthdr.len);
316 stat = ESP_STAT_BADILEN; /* Same as FreeBSD */
317 error = EINVAL;
318 goto out;
319 }
320
321 /* XXX don't pullup, just copy header */
322 M_REGION_GET(esp, struct newesp *, m, skip, sizeof(struct newesp));
323 if (esp == NULL) {
324 /* m already freed */
325 return ENOBUFS;
326 }
327
328 esph = sav->tdb_authalgxform;
329 espx = sav->tdb_encalgxform;
330 KASSERT(espx != NULL);
331
332 /* Determine the ESP header length */
333 if (sav->flags & SADB_X_EXT_OLD)
334 hlen = sizeof(struct esp) + sav->ivlen;
335 else
336 hlen = sizeof(struct newesp) + sav->ivlen;
337 /* Authenticator hash size */
338 alen = esph ? esph->authsize : 0;
339
340 /*
341 * Verify payload length is multiple of encryption algorithm block
342 * size.
343 *
344 * The payload must also be 4-byte-aligned. This is implicitly
345 * verified here too, since the blocksize is always 4-byte-aligned.
346 */
347 plen = m->m_pkthdr.len - (skip + hlen + alen);
348 KASSERT((espx->blocksize & 3) == 0);
349 if ((plen & (espx->blocksize - 1)) || (plen <= 0)) {
350 char buf[IPSEC_ADDRSTRLEN];
351 DPRINTF("payload of %d octets not a multiple of %d octets,"
352 " SA %s/%08lx\n", plen, espx->blocksize,
353 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
354 (u_long) ntohl(sav->spi));
355 stat = ESP_STAT_BADILEN;
356 error = EINVAL;
357 goto out;
358 }
359
360 /*
361 * Check sequence number.
362 */
363 if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) {
364 char logbuf[IPSEC_LOGSASTRLEN];
365 DPRINTF("packet replay check for %s\n",
366 ipsec_logsastr(sav, logbuf, sizeof(logbuf)));
367 stat = ESP_STAT_REPLAY;
368 error = EACCES;
369 goto out;
370 }
371
372 /* Update the counters */
373 ESP_STATADD(ESP_STAT_IBYTES, plen);
374
375 /* Get crypto descriptors */
376 crp = crypto_getreq(esph ? 2 : 1);
377 if (crp == NULL) {
378 DPRINTF("failed to acquire crypto descriptors\n");
379 error = ENOBUFS;
380 goto out;
381 }
382
383 /* Get IPsec-specific opaque pointer */
384 size_t extra __diagused = esph == NULL ? 0 : alen;
385 KASSERTMSG(sizeof(*tc) + extra <= esp_pool_item_size,
386 "sizeof(*tc) + extra=%zu > esp_pool_item_size=%zu\n",
387 sizeof(*tc) + extra, esp_pool_item_size);
388 tc = pool_cache_get(esp_tdb_crypto_pool_cache, PR_NOWAIT);
389 if (tc == NULL) {
390 DPRINTF("failed to allocate tdb_crypto\n");
391 error = ENOBUFS;
392 goto out1;
393 }
394
395 error = m_makewritable(&m, 0, m->m_pkthdr.len, M_NOWAIT);
396 if (error) {
397 DPRINTF("m_makewritable failed\n");
398 goto out2;
399 }
400
401 if (esph) {
402 struct cryptodesc *crda;
403
404 KASSERT(crp->crp_desc != NULL);
405 crda = crp->crp_desc;
406
407 /* Authentication descriptor */
408 crda->crd_skip = skip;
409 if (espx->type == CRYPTO_AES_GCM_16)
410 crda->crd_len = hlen - sav->ivlen;
411 else
412 crda->crd_len = m->m_pkthdr.len - (skip + alen);
413 crda->crd_inject = m->m_pkthdr.len - alen;
414
415 crda->crd_alg = esph->type;
416 if (espx->type == CRYPTO_AES_GCM_16 ||
417 espx->type == CRYPTO_AES_GMAC) {
418 crda->crd_key = _KEYBUF(sav->key_enc);
419 crda->crd_klen = _KEYBITS(sav->key_enc);
420 } else {
421 crda->crd_key = _KEYBUF(sav->key_auth);
422 crda->crd_klen = _KEYBITS(sav->key_auth);
423 }
424
425 /* Copy the authenticator */
426 m_copydata(m, m->m_pkthdr.len - alen, alen, (tc + 1));
427
428 /* Chain authentication request */
429 crde = crda->crd_next;
430 } else {
431 crde = crp->crp_desc;
432 }
433
434 {
435 int s = pserialize_read_enter();
436
437 /*
438 * Take another reference to the SA for opencrypto callback.
439 */
440 if (__predict_false(sav->state == SADB_SASTATE_DEAD)) {
441 pserialize_read_exit(s);
442 stat = ESP_STAT_NOTDB;
443 error = ENOENT;
444 goto out2;
445 }
446 KEY_SA_REF(sav);
447 pserialize_read_exit(s);
448 }
449
450 /* Crypto operation descriptor */
451 crp->crp_ilen = m->m_pkthdr.len; /* Total input length */
452 crp->crp_flags = CRYPTO_F_IMBUF;
453 crp->crp_buf = m;
454 crp->crp_callback = esp_input_cb;
455 crp->crp_sid = sav->tdb_cryptoid;
456 crp->crp_opaque = tc;
457
458 /* These are passed as-is to the callback */
459 tc->tc_spi = sav->spi;
460 tc->tc_dst = sav->sah->saidx.dst;
461 tc->tc_proto = sav->sah->saidx.proto;
462 tc->tc_protoff = protoff;
463 tc->tc_skip = skip;
464 tc->tc_sav = sav;
465
466 /* Decryption descriptor */
467 KASSERTMSG(crde != NULL, "null esp crypto descriptor");
468 crde->crd_skip = skip + hlen;
469 if (espx->type == CRYPTO_AES_GMAC)
470 crde->crd_len = 0;
471 else
472 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
473 crde->crd_inject = skip + hlen - sav->ivlen;
474 crde->crd_alg = espx->type;
475 crde->crd_key = _KEYBUF(sav->key_enc);
476 crde->crd_klen = _KEYBITS(sav->key_enc);
477 /* XXX Rounds ? */
478
479 crypto_dispatch(crp);
480 return 0;
481
482 out2:
483 pool_cache_put(esp_tdb_crypto_pool_cache, tc);
484 out1:
485 crypto_freereq(crp);
486 out:
487 ESP_STATINC(stat);
488 m_freem(m);
489 return error;
490 }
491
492 #ifdef INET6
493 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff) do { \
494 if (saidx->dst.sa.sa_family == AF_INET6) { \
495 (void)ipsec6_common_input_cb(m, sav, skip, protoff); \
496 } else { \
497 (void)ipsec4_common_input_cb(m, sav, skip, protoff); \
498 } \
499 } while (0)
500 #else
501 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff) \
502 ((void)ipsec4_common_input_cb(m, sav, skip, protoff))
503 #endif
504
505 /*
506 * ESP input callback from the crypto driver.
507 */
508 static void
esp_input_cb(struct cryptop * crp)509 esp_input_cb(struct cryptop *crp)
510 {
511 char buf[IPSEC_ADDRSTRLEN];
512 uint8_t lastthree[3], aalg[AH_ALEN_MAX];
513 int hlen, skip, protoff;
514 struct mbuf *m;
515 const struct auth_hash *esph;
516 struct tdb_crypto *tc;
517 struct secasvar *sav;
518 struct secasindex *saidx;
519 void *ptr;
520 IPSEC_DECLARE_LOCK_VARIABLE;
521
522 KASSERT(crp->crp_desc != NULL);
523 KASSERT(crp->crp_opaque != NULL);
524
525 tc = crp->crp_opaque;
526 skip = tc->tc_skip;
527 protoff = tc->tc_protoff;
528 m = crp->crp_buf;
529
530 IPSEC_ACQUIRE_GLOBAL_LOCKS();
531
532 sav = tc->tc_sav;
533 saidx = &sav->sah->saidx;
534 KASSERTMSG(saidx->dst.sa.sa_family == AF_INET ||
535 saidx->dst.sa.sa_family == AF_INET6,
536 "unexpected protocol family %u", saidx->dst.sa.sa_family);
537
538 esph = sav->tdb_authalgxform;
539
540 /* Check for crypto errors */
541 if (crp->crp_etype) {
542 /* Reset the session ID */
543 if (sav->tdb_cryptoid != 0)
544 sav->tdb_cryptoid = crp->crp_sid;
545
546 ESP_STATINC(ESP_STAT_NOXFORM);
547 DPRINTF("crypto error %d\n", crp->crp_etype);
548 goto bad;
549 }
550
551 ESP_STATINC(ESP_STAT_HIST + esp_stats[sav->alg_enc]);
552
553 /* If authentication was performed, check now. */
554 if (esph != NULL) {
555 /*
556 * If we have a tag, it means an IPsec-aware NIC did
557 * the verification for us. Otherwise we need to
558 * check the authentication calculation.
559 */
560 AH_STATINC(AH_STAT_HIST + ah_stats[sav->alg_auth]);
561 /* Copy the authenticator from the packet */
562 m_copydata(m, m->m_pkthdr.len - esph->authsize,
563 esph->authsize, aalg);
564
565 ptr = (tc + 1);
566
567 /* Verify authenticator */
568 if (!consttime_memequal(ptr, aalg, esph->authsize)) {
569 DPRINTF("authentication hash mismatch "
570 "for packet in SA %s/%08lx\n",
571 ipsec_address(&saidx->dst, buf,
572 sizeof(buf)), (u_long) ntohl(sav->spi));
573 ESP_STATINC(ESP_STAT_BADAUTH);
574 goto bad;
575 }
576
577 /* Remove trailing authenticator */
578 m_adj(m, -(esph->authsize));
579 }
580
581 /* Release the crypto descriptors */
582 pool_cache_put(esp_tdb_crypto_pool_cache, tc);
583 tc = NULL;
584 crypto_freereq(crp);
585 crp = NULL;
586
587 /*
588 * Packet is now decrypted.
589 */
590 m->m_flags |= M_DECRYPTED;
591
592 /*
593 * Update replay sequence number, if appropriate.
594 */
595 if (sav->replay) {
596 uint32_t seq;
597
598 m_copydata(m, skip + offsetof(struct newesp, esp_seq),
599 sizeof(seq), &seq);
600 if (ipsec_updatereplay(ntohl(seq), sav)) {
601 char logbuf[IPSEC_LOGSASTRLEN];
602 DPRINTF("packet replay check for %s\n",
603 ipsec_logsastr(sav, logbuf, sizeof(logbuf)));
604 ESP_STATINC(ESP_STAT_REPLAY);
605 goto bad;
606 }
607 }
608
609 /* Determine the ESP header length */
610 if (sav->flags & SADB_X_EXT_OLD)
611 hlen = sizeof(struct esp) + sav->ivlen;
612 else
613 hlen = sizeof(struct newesp) + sav->ivlen;
614
615 /* Remove the ESP header and IV from the mbuf. */
616 if (m_striphdr(m, skip, hlen) != 0) {
617 ESP_STATINC(ESP_STAT_HDROPS);
618 DPRINTF("bad mbuf chain, SA %s/%08lx\n",
619 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
620 (u_long) ntohl(sav->spi));
621 goto bad;
622 }
623
624 /* Save the last three bytes of decrypted data */
625 m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree);
626
627 /* Verify pad length */
628 if (lastthree[1] + 2 > m->m_pkthdr.len - skip) {
629 ESP_STATINC(ESP_STAT_BADILEN);
630 DPRINTF("invalid padding length %d "
631 "for %u byte packet in SA %s/%08lx\n",
632 lastthree[1], m->m_pkthdr.len - skip,
633 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
634 (u_long) ntohl(sav->spi));
635 goto bad;
636 }
637
638 /* Verify correct decryption by checking the last padding bytes */
639 if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) {
640 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) {
641 ESP_STATINC(ESP_STAT_BADENC);
642 DPRINTF("decryption failed for packet in SA "
643 "%s/%08lx\n",
644 ipsec_address(&sav->sah->saidx.dst, buf,
645 sizeof(buf)), (u_long) ntohl(sav->spi));
646 DPRINTF("%x %x\n", lastthree[0],
647 lastthree[1]);
648 goto bad;
649 }
650 }
651
652 /* Trim the mbuf chain to remove trailing authenticator and padding */
653 m_adj(m, -(lastthree[1] + 2));
654
655 /* Restore the Next Protocol field */
656 m_copyback(m, protoff, sizeof(uint8_t), lastthree + 2);
657
658 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff);
659
660 KEY_SA_UNREF(&sav);
661 IPSEC_RELEASE_GLOBAL_LOCKS();
662 return;
663 bad:
664 if (sav)
665 KEY_SA_UNREF(&sav);
666 IPSEC_RELEASE_GLOBAL_LOCKS();
667 m_freem(m);
668 if (tc != NULL)
669 pool_cache_put(esp_tdb_crypto_pool_cache, tc);
670 if (crp != NULL)
671 crypto_freereq(crp);
672 }
673
674 /*
675 * ESP output routine, called by ipsec[46]_process_packet().
676 */
677 static int
esp_output(struct mbuf * m,const struct ipsecrequest * isr,struct secasvar * sav,int skip,int protoff,int flags)678 esp_output(struct mbuf *m, const struct ipsecrequest *isr, struct secasvar *sav,
679 int skip, int protoff, int flags)
680 {
681 char buf[IPSEC_ADDRSTRLEN];
682 const struct enc_xform *espx;
683 const struct auth_hash *esph;
684 int hlen, rlen, tlen, padlen, blks, alen, i, roff;
685 struct mbuf *mo = NULL;
686 struct tdb_crypto *tc;
687 struct secasindex *saidx;
688 unsigned char *tail;
689 uint8_t prot;
690 int error, maxpacketsize;
691 struct esptail *esptail;
692 struct cryptodesc *crde, *crda;
693 struct cryptop *crp;
694
695 esph = sav->tdb_authalgxform;
696 espx = sav->tdb_encalgxform;
697 KASSERT(espx != NULL);
698
699 /* Determine the ESP header length */
700 if (sav->flags & SADB_X_EXT_OLD)
701 hlen = sizeof(struct esp) + sav->ivlen;
702 else
703 hlen = sizeof(struct newesp) + sav->ivlen;
704 /* Authenticator hash size */
705 alen = esph ? esph->authsize : 0;
706
707 /*
708 * NB: The null encoding transform has a blocksize of 4
709 * so that headers are properly aligned.
710 */
711 blks = espx->blocksize; /* IV blocksize */
712
713 /* Raw payload length. */
714 rlen = m->m_pkthdr.len - skip;
715
716 /* Encryption padding. */
717 padlen = ((blks - ((rlen + sizeof(struct esptail)) % blks)) % blks);
718
719 /* Length of what we append (tail). */
720 tlen = padlen + sizeof(struct esptail) + alen;
721
722 ESP_STATINC(ESP_STAT_OUTPUT);
723
724 saidx = &sav->sah->saidx;
725 /* Check for maximum packet size violations. */
726 switch (saidx->dst.sa.sa_family) {
727 #ifdef INET
728 case AF_INET:
729 maxpacketsize = IP_MAXPACKET;
730 break;
731 #endif
732 #ifdef INET6
733 case AF_INET6:
734 maxpacketsize = IPV6_MAXPACKET;
735 break;
736 #endif
737 default:
738 DPRINTF("unknown/unsupported protocol family %d, "
739 "SA %s/%08lx\n", saidx->dst.sa.sa_family,
740 ipsec_address(&saidx->dst, buf, sizeof(buf)),
741 (u_long)ntohl(sav->spi));
742 ESP_STATINC(ESP_STAT_NOPF);
743 error = EPFNOSUPPORT;
744 goto bad;
745 }
746 if (skip + hlen + rlen + tlen > maxpacketsize) {
747 DPRINTF("packet in SA %s/%08lx got too big (len %u, "
748 "max len %u)\n",
749 ipsec_address(&saidx->dst, buf, sizeof(buf)),
750 (u_long) ntohl(sav->spi),
751 skip + hlen + rlen + tlen, maxpacketsize);
752 ESP_STATINC(ESP_STAT_TOOBIG);
753 error = EMSGSIZE;
754 goto bad;
755 }
756
757 /* Update the counters. */
758 ESP_STATADD(ESP_STAT_OBYTES, m->m_pkthdr.len - skip);
759
760 m = m_clone(m);
761 if (m == NULL) {
762 DPRINTF("cannot clone mbuf chain, SA %s/%08lx\n",
763 ipsec_address(&saidx->dst, buf, sizeof(buf)),
764 (u_long) ntohl(sav->spi));
765 ESP_STATINC(ESP_STAT_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("failed to inject %u byte ESP hdr for SA "
774 "%s/%08lx\n", hlen,
775 ipsec_address(&saidx->dst, buf, sizeof(buf)),
776 (u_long) ntohl(sav->spi));
777 ESP_STATINC(ESP_STAT_HDROPS);
778 error = ENOBUFS;
779 goto bad;
780 }
781
782 /* Initialize ESP header. */
783 memcpy(mtod(mo, char *) + roff, &sav->spi, sizeof(uint32_t));
784 if (sav->replay) {
785 uint32_t replay;
786
787 #ifdef IPSEC_DEBUG
788 /* Emulate replay attack when ipsec_replay is TRUE. */
789 if (ipsec_replay)
790 replay = htonl(sav->replay->count);
791 else
792 #endif
793 replay = htonl(atomic_inc_32_nv(&sav->replay->count));
794
795 memcpy(mtod(mo,char *) + roff + sizeof(uint32_t), &replay,
796 sizeof(uint32_t));
797 }
798
799 /*
800 * Grow the mbuf, we will append data at the tail.
801 */
802 tail = m_pad(m, tlen);
803 if (tail == NULL) {
804 DPRINTF("m_pad failed for SA %s/%08lx\n",
805 ipsec_address(&saidx->dst, buf, sizeof(buf)),
806 (u_long) ntohl(sav->spi));
807 m = NULL;
808 error = ENOBUFS;
809 goto bad;
810 }
811
812 /*
813 * Add padding: random, zero, or self-describing.
814 */
815 switch (sav->flags & SADB_X_EXT_PMASK) {
816 case SADB_X_EXT_PSEQ:
817 for (i = 0; i < padlen; i++)
818 tail[i] = i + 1;
819 break;
820 case SADB_X_EXT_PRAND:
821 (void)cprng_fast(tail, padlen);
822 break;
823 case SADB_X_EXT_PZERO:
824 default:
825 memset(tail, 0, padlen);
826 break;
827 }
828
829 /* Build the ESP Trailer. */
830 esptail = (struct esptail *)&tail[padlen];
831 esptail->esp_padlen = padlen;
832 m_copydata(m, protoff, sizeof(uint8_t), &esptail->esp_nxt);
833
834 /* Fix Next Protocol in IPv4/IPv6 header. */
835 prot = IPPROTO_ESP;
836 m_copyback(m, protoff, sizeof(uint8_t), &prot);
837
838 /* Get crypto descriptors. */
839 crp = crypto_getreq(esph ? 2 : 1);
840 if (crp == NULL) {
841 DPRINTF("failed to acquire crypto descriptors\n");
842 ESP_STATINC(ESP_STAT_CRYPTO);
843 error = ENOBUFS;
844 goto bad;
845 }
846
847 /* Get the descriptors. */
848 crde = crp->crp_desc;
849 crda = crde->crd_next;
850
851 /* Encryption descriptor. */
852 crde->crd_skip = skip + hlen;
853 if (espx->type == CRYPTO_AES_GMAC)
854 crde->crd_len = 0;
855 else
856 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
857 crde->crd_flags = CRD_F_ENCRYPT;
858 crde->crd_inject = skip + hlen - sav->ivlen;
859 crde->crd_alg = espx->type;
860 crde->crd_key = _KEYBUF(sav->key_enc);
861 crde->crd_klen = _KEYBITS(sav->key_enc);
862 /* XXX Rounds ? */
863
864 /* IPsec-specific opaque crypto info. */
865 tc = pool_cache_get(esp_tdb_crypto_pool_cache, PR_NOWAIT);
866 if (tc == NULL) {
867 crypto_freereq(crp);
868 DPRINTF("failed to allocate tdb_crypto\n");
869 ESP_STATINC(ESP_STAT_CRYPTO);
870 error = ENOBUFS;
871 goto bad;
872 }
873
874 {
875 int s = pserialize_read_enter();
876
877 /*
878 * Take another reference to the SP and the SA for opencrypto callback.
879 */
880 if (__predict_false(isr->sp->state == IPSEC_SPSTATE_DEAD ||
881 sav->state == SADB_SASTATE_DEAD)) {
882 pserialize_read_exit(s);
883 pool_cache_put(esp_tdb_crypto_pool_cache, tc);
884 crypto_freereq(crp);
885 ESP_STATINC(ESP_STAT_NOTDB);
886 error = ENOENT;
887 goto bad;
888 }
889 KEY_SP_REF(isr->sp);
890 KEY_SA_REF(sav);
891 pserialize_read_exit(s);
892 }
893
894 /* Callback parameters */
895 tc->tc_isr = isr;
896 tc->tc_spi = sav->spi;
897 tc->tc_dst = saidx->dst;
898 tc->tc_proto = saidx->proto;
899 tc->tc_flags = flags;
900 tc->tc_sav = sav;
901
902 /* Crypto operation descriptor. */
903 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
904 crp->crp_flags = CRYPTO_F_IMBUF;
905 crp->crp_buf = m;
906 crp->crp_callback = esp_output_cb;
907 crp->crp_opaque = tc;
908 crp->crp_sid = sav->tdb_cryptoid;
909
910 if (esph) {
911 /* Authentication descriptor. */
912 crda->crd_skip = skip;
913 if (espx->type == CRYPTO_AES_GCM_16)
914 crda->crd_len = hlen - sav->ivlen;
915 else
916 crda->crd_len = m->m_pkthdr.len - (skip + alen);
917 crda->crd_inject = m->m_pkthdr.len - alen;
918
919 /* Authentication operation. */
920 crda->crd_alg = esph->type;
921 if (espx->type == CRYPTO_AES_GCM_16 ||
922 espx->type == CRYPTO_AES_GMAC) {
923 crda->crd_key = _KEYBUF(sav->key_enc);
924 crda->crd_klen = _KEYBITS(sav->key_enc);
925 } else {
926 crda->crd_key = _KEYBUF(sav->key_auth);
927 crda->crd_klen = _KEYBITS(sav->key_auth);
928 }
929 }
930
931 crypto_dispatch(crp);
932 return 0;
933
934 bad:
935 m_freem(m);
936 return error;
937 }
938
939 /*
940 * ESP output callback from the crypto driver.
941 */
942 static void
esp_output_cb(struct cryptop * crp)943 esp_output_cb(struct cryptop *crp)
944 {
945 struct tdb_crypto *tc;
946 const struct ipsecrequest *isr;
947 struct secasvar *sav;
948 struct mbuf *m;
949 int flags;
950 IPSEC_DECLARE_LOCK_VARIABLE;
951
952 KASSERT(crp->crp_opaque != NULL);
953 tc = crp->crp_opaque;
954 m = crp->crp_buf;
955
956 IPSEC_ACQUIRE_GLOBAL_LOCKS();
957
958 isr = tc->tc_isr;
959 sav = tc->tc_sav;
960
961 /* Check for crypto errors. */
962 if (crp->crp_etype) {
963 /* Reset session ID. */
964 if (sav->tdb_cryptoid != 0)
965 sav->tdb_cryptoid = crp->crp_sid;
966
967 ESP_STATINC(ESP_STAT_NOXFORM);
968 DPRINTF("crypto error %d\n", crp->crp_etype);
969 goto bad;
970 }
971
972 ESP_STATINC(ESP_STAT_HIST + esp_stats[sav->alg_enc]);
973 if (sav->tdb_authalgxform != NULL)
974 AH_STATINC(AH_STAT_HIST + ah_stats[sav->alg_auth]);
975
976 flags = tc->tc_flags;
977 /* Release crypto descriptors. */
978 pool_cache_put(esp_tdb_crypto_pool_cache, tc);
979 crypto_freereq(crp);
980
981 #ifdef IPSEC_DEBUG
982 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
983 if (ipsec_integrity) {
984 static unsigned char ipseczeroes[AH_ALEN_MAX];
985 const struct auth_hash *esph;
986
987 /*
988 * Corrupt HMAC if we want to test integrity verification of
989 * the other side.
990 */
991 esph = sav->tdb_authalgxform;
992 if (esph != NULL) {
993 m_copyback(m, m->m_pkthdr.len - esph->authsize,
994 esph->authsize, ipseczeroes);
995 }
996 }
997 #endif
998
999 /* NB: m is reclaimed by ipsec_process_done. */
1000 (void)ipsec_process_done(m, isr, sav, flags);
1001 KEY_SA_UNREF(&sav);
1002 KEY_SP_UNREF(&isr->sp);
1003 IPSEC_RELEASE_GLOBAL_LOCKS();
1004 return;
1005
1006 bad:
1007 if (sav)
1008 KEY_SA_UNREF(&sav);
1009 KEY_SP_UNREF(&isr->sp);
1010 IPSEC_RELEASE_GLOBAL_LOCKS();
1011 m_freem(m);
1012 pool_cache_put(esp_tdb_crypto_pool_cache, tc);
1013 crypto_freereq(crp);
1014 }
1015
1016 static struct xformsw esp_xformsw = {
1017 .xf_type = XF_ESP,
1018 .xf_flags = XFT_CONF|XFT_AUTH,
1019 .xf_name = "IPsec ESP",
1020 .xf_init = esp_init,
1021 .xf_zeroize = esp_zeroize,
1022 .xf_input = esp_input,
1023 .xf_output = esp_output,
1024 .xf_next = NULL,
1025 };
1026
1027 void
esp_attach(void)1028 esp_attach(void)
1029 {
1030
1031 espstat_percpu = percpu_alloc(sizeof(uint64_t) * ESP_NSTATS);
1032
1033 extern int ah_max_authsize;
1034 KASSERT(ah_max_authsize != 0);
1035 esp_pool_item_size = sizeof(struct tdb_crypto) + ah_max_authsize;
1036 esp_tdb_crypto_pool_cache = pool_cache_init(esp_pool_item_size,
1037 coherency_unit, 0, 0, "esp_tdb_crypto", NULL, IPL_SOFTNET,
1038 NULL, NULL, NULL);
1039
1040 #define MAXIV(xform) \
1041 if (xform.ivsize > esp_max_ivlen) \
1042 esp_max_ivlen = xform.ivsize \
1043
1044 esp_max_ivlen = 0;
1045 MAXIV(enc_xform_des); /* SADB_EALG_DESCBC */
1046 MAXIV(enc_xform_3des); /* SADB_EALG_3DESCBC */
1047 MAXIV(enc_xform_aes); /* SADB_X_EALG_AES */
1048 MAXIV(enc_xform_blf); /* SADB_X_EALG_BLOWFISHCBC */
1049 MAXIV(enc_xform_cast5); /* SADB_X_EALG_CAST128CBC */
1050 MAXIV(enc_xform_skipjack); /* SADB_X_EALG_SKIPJACK */
1051 MAXIV(enc_xform_camellia); /* SADB_X_EALG_CAMELLIACBC */
1052 MAXIV(enc_xform_aes_ctr); /* SADB_X_EALG_AESCTR */
1053 MAXIV(enc_xform_null); /* SADB_EALG_NULL */
1054
1055 xform_register(&esp_xformsw);
1056 #undef MAXIV
1057 }
1058