xref: /openbsd/sys/crypto/xform.c (revision 4cfece93)
1 /*	$OpenBSD: xform.c,v 1.59 2018/04/09 04:34:56 visa Exp $	*/
2 /*
3  * The authors of this code are John Ioannidis (ji@tla.org),
4  * Angelos D. Keromytis (kermit@csd.uch.gr),
5  * Niels Provos (provos@physnet.uni-hamburg.de),
6  * Damien Miller (djm@mindrot.org) and
7  * Mike Belopuhov (mikeb@openbsd.org).
8  *
9  * This code was written by John Ioannidis for BSD/OS in Athens, Greece,
10  * in November 1995.
11  *
12  * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
13  * by Angelos D. Keromytis.
14  *
15  * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
16  * and Niels Provos.
17  *
18  * Additional features in 1999 by Angelos D. Keromytis.
19  *
20  * AES XTS implementation in 2008 by Damien Miller
21  *
22  * AES-GCM-16 and Chacha20-Poly1305 AEAD modes by Mike Belopuhov.
23  *
24  * Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
25  * Angelos D. Keromytis and Niels Provos.
26  *
27  * Copyright (C) 2001, Angelos D. Keromytis.
28  *
29  * Copyright (C) 2008, Damien Miller
30  *
31  * Copyright (C) 2010, 2015, Mike Belopuhov
32  *
33  * Permission to use, copy, and modify this software with or without fee
34  * is hereby granted, provided that this entire notice is included in
35  * all copies of any software which is or includes a copy or
36  * modification of this software.
37  * You may use this code under the GNU public license if you so wish. Please
38  * contribute changes back to the authors under this freer than GPL license
39  * so that we may further the use of strong encryption without limitations to
40  * all.
41  *
42  * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
43  * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
44  * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
45  * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
46  * PURPOSE.
47  */
48 
49 #include <sys/param.h>
50 #include <sys/systm.h>
51 #include <sys/errno.h>
52 #include <sys/time.h>
53 #include <sys/kernel.h>
54 #include <machine/cpu.h>
55 
56 #include <crypto/md5.h>
57 #include <crypto/sha1.h>
58 #include <crypto/sha2.h>
59 #include <crypto/rmd160.h>
60 #include <crypto/blf.h>
61 #include <crypto/cast.h>
62 #include <crypto/rijndael.h>
63 #include <crypto/aes.h>
64 #include <crypto/cryptodev.h>
65 #include <crypto/xform.h>
66 #include <crypto/gmac.h>
67 #include <crypto/chachapoly.h>
68 
69 extern void des_ecb3_encrypt(caddr_t, caddr_t, caddr_t, caddr_t, caddr_t, int);
70 
71 int  des_set_key(void *, caddr_t);
72 int  des3_setkey(void *, u_int8_t *, int);
73 int  blf_setkey(void *, u_int8_t *, int);
74 int  cast5_setkey(void *, u_int8_t *, int);
75 int  aes_setkey(void *, u_int8_t *, int);
76 int  aes_ctr_setkey(void *, u_int8_t *, int);
77 int  aes_xts_setkey(void *, u_int8_t *, int);
78 int  null_setkey(void *, u_int8_t *, int);
79 
80 void des3_encrypt(caddr_t, u_int8_t *);
81 void blf_encrypt(caddr_t, u_int8_t *);
82 void cast5_encrypt(caddr_t, u_int8_t *);
83 void aes_encrypt(caddr_t, u_int8_t *);
84 void null_encrypt(caddr_t, u_int8_t *);
85 void aes_xts_encrypt(caddr_t, u_int8_t *);
86 
87 void des3_decrypt(caddr_t, u_int8_t *);
88 void blf_decrypt(caddr_t, u_int8_t *);
89 void cast5_decrypt(caddr_t, u_int8_t *);
90 void aes_decrypt(caddr_t, u_int8_t *);
91 void null_decrypt(caddr_t, u_int8_t *);
92 void aes_xts_decrypt(caddr_t, u_int8_t *);
93 
94 void aes_ctr_crypt(caddr_t, u_int8_t *);
95 
96 void aes_ctr_reinit(caddr_t, u_int8_t *);
97 void aes_xts_reinit(caddr_t, u_int8_t *);
98 void aes_gcm_reinit(caddr_t, u_int8_t *);
99 
100 int MD5Update_int(void *, const u_int8_t *, u_int16_t);
101 int SHA1Update_int(void *, const u_int8_t *, u_int16_t);
102 int RMD160Update_int(void *, const u_int8_t *, u_int16_t);
103 int SHA256Update_int(void *, const u_int8_t *, u_int16_t);
104 int SHA384Update_int(void *, const u_int8_t *, u_int16_t);
105 int SHA512Update_int(void *, const u_int8_t *, u_int16_t);
106 
107 u_int32_t deflate_compress(u_int8_t *, u_int32_t, u_int8_t **);
108 u_int32_t deflate_decompress(u_int8_t *, u_int32_t, u_int8_t **);
109 u_int32_t lzs_dummy(u_int8_t *, u_int32_t, u_int8_t **);
110 
111 struct aes_ctr_ctx {
112 	AES_CTX		ac_key;
113 	u_int8_t	ac_block[AESCTR_BLOCKSIZE];
114 };
115 
116 struct aes_xts_ctx {
117 	rijndael_ctx key1;
118 	rijndael_ctx key2;
119 	u_int8_t tweak[AES_XTS_BLOCKSIZE];
120 };
121 
122 /* Helper */
123 void aes_xts_crypt(struct aes_xts_ctx *, u_int8_t *, u_int);
124 
125 /* Encryption instances */
126 struct enc_xform enc_xform_3des = {
127 	CRYPTO_3DES_CBC, "3DES",
128 	8, 8, 24, 24, 384,
129 	des3_encrypt,
130 	des3_decrypt,
131 	des3_setkey,
132 	NULL
133 };
134 
135 struct enc_xform enc_xform_blf = {
136 	CRYPTO_BLF_CBC, "Blowfish",
137 	8, 8, 5, 56 /* 448 bits, max key */,
138 	sizeof(blf_ctx),
139 	blf_encrypt,
140 	blf_decrypt,
141 	blf_setkey,
142 	NULL
143 };
144 
145 struct enc_xform enc_xform_cast5 = {
146 	CRYPTO_CAST_CBC, "CAST-128",
147 	8, 8, 5, 16,
148 	sizeof(cast_key),
149 	cast5_encrypt,
150 	cast5_decrypt,
151 	cast5_setkey,
152 	NULL
153 };
154 
155 struct enc_xform enc_xform_aes = {
156 	CRYPTO_AES_CBC, "AES",
157 	16, 16, 16, 32,
158 	sizeof(AES_CTX),
159 	aes_encrypt,
160 	aes_decrypt,
161 	aes_setkey,
162 	NULL
163 };
164 
165 struct enc_xform enc_xform_aes_ctr = {
166 	CRYPTO_AES_CTR, "AES-CTR",
167 	16, 8, 16+4, 32+4,
168 	sizeof(struct aes_ctr_ctx),
169 	aes_ctr_crypt,
170 	aes_ctr_crypt,
171 	aes_ctr_setkey,
172 	aes_ctr_reinit
173 };
174 
175 struct enc_xform enc_xform_aes_gcm = {
176 	CRYPTO_AES_GCM_16, "AES-GCM",
177 	1, 8, 16+4, 32+4,
178 	sizeof(struct aes_ctr_ctx),
179 	aes_ctr_crypt,
180 	aes_ctr_crypt,
181 	aes_ctr_setkey,
182 	aes_gcm_reinit
183 };
184 
185 struct enc_xform enc_xform_aes_gmac = {
186 	CRYPTO_AES_GMAC, "AES-GMAC",
187 	1, 8, 16+4, 32+4, 0,
188 	NULL,
189 	NULL,
190 	NULL,
191 	NULL
192 };
193 
194 struct enc_xform enc_xform_aes_xts = {
195 	CRYPTO_AES_XTS, "AES-XTS",
196 	16, 8, 32, 64,
197 	sizeof(struct aes_xts_ctx),
198 	aes_xts_encrypt,
199 	aes_xts_decrypt,
200 	aes_xts_setkey,
201 	aes_xts_reinit
202 };
203 
204 struct enc_xform enc_xform_chacha20_poly1305 = {
205 	CRYPTO_CHACHA20_POLY1305, "CHACHA20-POLY1305",
206 	1, 8, 32+4, 32+4,
207 	sizeof(struct chacha20_ctx),
208 	chacha20_crypt,
209 	chacha20_crypt,
210 	chacha20_setkey,
211 	chacha20_reinit
212 };
213 
214 struct enc_xform enc_xform_null = {
215 	CRYPTO_NULL, "NULL",
216 	4, 0, 0, 256, 0,
217 	null_encrypt,
218 	null_decrypt,
219 	null_setkey,
220 	NULL
221 };
222 
223 /* Authentication instances */
224 struct auth_hash auth_hash_hmac_md5_96 = {
225 	CRYPTO_MD5_HMAC, "HMAC-MD5",
226 	16, 16, 12, sizeof(MD5_CTX), HMAC_MD5_BLOCK_LEN,
227 	(void (*) (void *)) MD5Init, NULL, NULL,
228 	MD5Update_int,
229 	(void (*) (u_int8_t *, void *)) MD5Final
230 };
231 
232 struct auth_hash auth_hash_hmac_sha1_96 = {
233 	CRYPTO_SHA1_HMAC, "HMAC-SHA1",
234 	20, 20, 12, sizeof(SHA1_CTX), HMAC_SHA1_BLOCK_LEN,
235 	(void (*) (void *)) SHA1Init, NULL, NULL,
236 	SHA1Update_int,
237 	(void (*) (u_int8_t *, void *)) SHA1Final
238 };
239 
240 struct auth_hash auth_hash_hmac_ripemd_160_96 = {
241 	CRYPTO_RIPEMD160_HMAC, "HMAC-RIPEMD-160",
242 	20, 20, 12, sizeof(RMD160_CTX), HMAC_RIPEMD160_BLOCK_LEN,
243 	(void (*)(void *)) RMD160Init, NULL, NULL,
244 	RMD160Update_int,
245 	(void (*)(u_int8_t *, void *)) RMD160Final
246 };
247 
248 struct auth_hash auth_hash_hmac_sha2_256_128 = {
249 	CRYPTO_SHA2_256_HMAC, "HMAC-SHA2-256",
250 	32, 32, 16, sizeof(SHA2_CTX), HMAC_SHA2_256_BLOCK_LEN,
251 	(void (*)(void *)) SHA256Init, NULL, NULL,
252 	SHA256Update_int,
253 	(void (*)(u_int8_t *, void *)) SHA256Final
254 };
255 
256 struct auth_hash auth_hash_hmac_sha2_384_192 = {
257 	CRYPTO_SHA2_384_HMAC, "HMAC-SHA2-384",
258 	48, 48, 24, sizeof(SHA2_CTX), HMAC_SHA2_384_BLOCK_LEN,
259 	(void (*)(void *)) SHA384Init, NULL, NULL,
260 	SHA384Update_int,
261 	(void (*)(u_int8_t *, void *)) SHA384Final
262 };
263 
264 struct auth_hash auth_hash_hmac_sha2_512_256 = {
265 	CRYPTO_SHA2_512_HMAC, "HMAC-SHA2-512",
266 	64, 64, 32, sizeof(SHA2_CTX), HMAC_SHA2_512_BLOCK_LEN,
267 	(void (*)(void *)) SHA512Init, NULL, NULL,
268 	SHA512Update_int,
269 	(void (*)(u_int8_t *, void *)) SHA512Final
270 };
271 
272 struct auth_hash auth_hash_gmac_aes_128 = {
273 	CRYPTO_AES_128_GMAC, "GMAC-AES-128",
274 	16+4, GMAC_BLOCK_LEN, GMAC_DIGEST_LEN, sizeof(AES_GMAC_CTX),
275 	AESCTR_BLOCKSIZE, AES_GMAC_Init, AES_GMAC_Setkey, AES_GMAC_Reinit,
276 	AES_GMAC_Update, AES_GMAC_Final
277 };
278 
279 struct auth_hash auth_hash_gmac_aes_192 = {
280 	CRYPTO_AES_192_GMAC, "GMAC-AES-192",
281 	24+4, GMAC_BLOCK_LEN, GMAC_DIGEST_LEN, sizeof(AES_GMAC_CTX),
282 	AESCTR_BLOCKSIZE, AES_GMAC_Init, AES_GMAC_Setkey, AES_GMAC_Reinit,
283 	AES_GMAC_Update, AES_GMAC_Final
284 };
285 
286 struct auth_hash auth_hash_gmac_aes_256 = {
287 	CRYPTO_AES_256_GMAC, "GMAC-AES-256",
288 	32+4, GMAC_BLOCK_LEN, GMAC_DIGEST_LEN, sizeof(AES_GMAC_CTX),
289 	AESCTR_BLOCKSIZE, AES_GMAC_Init, AES_GMAC_Setkey, AES_GMAC_Reinit,
290 	AES_GMAC_Update, AES_GMAC_Final
291 };
292 
293 struct auth_hash auth_hash_chacha20_poly1305 = {
294 	CRYPTO_CHACHA20_POLY1305_MAC, "CHACHA20-POLY1305",
295 	CHACHA20_KEYSIZE+CHACHA20_SALT, POLY1305_BLOCK_LEN, POLY1305_TAGLEN,
296 	sizeof(CHACHA20_POLY1305_CTX), CHACHA20_BLOCK_LEN,
297 	Chacha20_Poly1305_Init, Chacha20_Poly1305_Setkey,
298 	Chacha20_Poly1305_Reinit, Chacha20_Poly1305_Update,
299 	Chacha20_Poly1305_Final
300 };
301 
302 /* Compression instance */
303 struct comp_algo comp_algo_deflate = {
304 	CRYPTO_DEFLATE_COMP, "Deflate",
305 	90, deflate_compress,
306 	deflate_decompress
307 };
308 
309 struct comp_algo comp_algo_lzs = {
310 	CRYPTO_LZS_COMP, "LZS",
311 	90, lzs_dummy,
312 	lzs_dummy
313 };
314 
315 /*
316  * Encryption wrapper routines.
317  */
318 void
319 des3_encrypt(caddr_t key, u_int8_t *blk)
320 {
321 	des_ecb3_encrypt(blk, blk, key, key + 128, key + 256, 1);
322 }
323 
324 void
325 des3_decrypt(caddr_t key, u_int8_t *blk)
326 {
327 	des_ecb3_encrypt(blk, blk, key + 256, key + 128, key, 0);
328 }
329 
330 int
331 des3_setkey(void *sched, u_int8_t *key, int len)
332 {
333 	if (des_set_key(key, sched) < 0 || des_set_key(key + 8, sched + 128)
334 	    < 0 || des_set_key(key + 16, sched + 256) < 0)
335 		return -1;
336 
337 	return 0;
338 }
339 
340 void
341 blf_encrypt(caddr_t key, u_int8_t *blk)
342 {
343 	blf_ecb_encrypt((blf_ctx *) key, blk, 8);
344 }
345 
346 void
347 blf_decrypt(caddr_t key, u_int8_t *blk)
348 {
349 	blf_ecb_decrypt((blf_ctx *) key, blk, 8);
350 }
351 
352 int
353 blf_setkey(void *sched, u_int8_t *key, int len)
354 {
355 	blf_key((blf_ctx *)sched, key, len);
356 
357 	return 0;
358 }
359 
360 int
361 null_setkey(void *sched, u_int8_t *key, int len)
362 {
363 	return 0;
364 }
365 
366 void
367 null_encrypt(caddr_t key, u_int8_t *blk)
368 {
369 }
370 
371 void
372 null_decrypt(caddr_t key, u_int8_t *blk)
373 {
374 }
375 
376 void
377 cast5_encrypt(caddr_t key, u_int8_t *blk)
378 {
379 	cast_encrypt((cast_key *) key, blk, blk);
380 }
381 
382 void
383 cast5_decrypt(caddr_t key, u_int8_t *blk)
384 {
385 	cast_decrypt((cast_key *) key, blk, blk);
386 }
387 
388 int
389 cast5_setkey(void *sched, u_int8_t *key, int len)
390 {
391 	cast_setkey((cast_key *)sched, key, len);
392 
393 	return 0;
394 }
395 
396 void
397 aes_encrypt(caddr_t key, u_int8_t *blk)
398 {
399 	AES_Encrypt((AES_CTX *)key, blk, blk);
400 }
401 
402 void
403 aes_decrypt(caddr_t key, u_int8_t *blk)
404 {
405 	AES_Decrypt((AES_CTX *)key, blk, blk);
406 }
407 
408 int
409 aes_setkey(void *sched, u_int8_t *key, int len)
410 {
411 	return AES_Setkey((AES_CTX *)sched, key, len);
412 }
413 
414 void
415 aes_ctr_reinit(caddr_t key, u_int8_t *iv)
416 {
417 	struct aes_ctr_ctx *ctx;
418 
419 	ctx = (struct aes_ctr_ctx *)key;
420 	bcopy(iv, ctx->ac_block + AESCTR_NONCESIZE, AESCTR_IVSIZE);
421 
422 	/* reset counter */
423 	bzero(ctx->ac_block + AESCTR_NONCESIZE + AESCTR_IVSIZE, 4);
424 }
425 
426 void
427 aes_gcm_reinit(caddr_t key, u_int8_t *iv)
428 {
429 	struct aes_ctr_ctx *ctx;
430 
431 	ctx = (struct aes_ctr_ctx *)key;
432 	bcopy(iv, ctx->ac_block + AESCTR_NONCESIZE, AESCTR_IVSIZE);
433 
434 	/* reset counter */
435 	bzero(ctx->ac_block + AESCTR_NONCESIZE + AESCTR_IVSIZE, 4);
436 	ctx->ac_block[AESCTR_BLOCKSIZE - 1] = 1; /* GCM starts with 1 */
437 }
438 
439 void
440 aes_ctr_crypt(caddr_t key, u_int8_t *data)
441 {
442 	struct aes_ctr_ctx *ctx;
443 	u_int8_t keystream[AESCTR_BLOCKSIZE];
444 	int i;
445 
446 	ctx = (struct aes_ctr_ctx *)key;
447 	/* increment counter */
448 	for (i = AESCTR_BLOCKSIZE - 1;
449 	     i >= AESCTR_NONCESIZE + AESCTR_IVSIZE; i--)
450 		if (++ctx->ac_block[i])   /* continue on overflow */
451 			break;
452 	AES_Encrypt(&ctx->ac_key, ctx->ac_block, keystream);
453 	for (i = 0; i < AESCTR_BLOCKSIZE; i++)
454 		data[i] ^= keystream[i];
455 	explicit_bzero(keystream, sizeof(keystream));
456 }
457 
458 int
459 aes_ctr_setkey(void *sched, u_int8_t *key, int len)
460 {
461 	struct aes_ctr_ctx *ctx;
462 
463 	if (len < AESCTR_NONCESIZE)
464 		return -1;
465 
466 	ctx = (struct aes_ctr_ctx *)sched;
467 	if (AES_Setkey(&ctx->ac_key, key, len - AESCTR_NONCESIZE) != 0)
468 		return -1;
469 	bcopy(key + len - AESCTR_NONCESIZE, ctx->ac_block, AESCTR_NONCESIZE);
470 	return 0;
471 }
472 
473 void
474 aes_xts_reinit(caddr_t key, u_int8_t *iv)
475 {
476 	struct aes_xts_ctx *ctx = (struct aes_xts_ctx *)key;
477 	u_int64_t blocknum;
478 	u_int i;
479 
480 	/*
481 	 * Prepare tweak as E_k2(IV). IV is specified as LE representation
482 	 * of a 64-bit block number which we allow to be passed in directly.
483 	 */
484 	memcpy(&blocknum, iv, AES_XTS_IVSIZE);
485 	for (i = 0; i < AES_XTS_IVSIZE; i++) {
486 		ctx->tweak[i] = blocknum & 0xff;
487 		blocknum >>= 8;
488 	}
489 	/* Last 64 bits of IV are always zero */
490 	bzero(ctx->tweak + AES_XTS_IVSIZE, AES_XTS_IVSIZE);
491 
492 	rijndael_encrypt(&ctx->key2, ctx->tweak, ctx->tweak);
493 }
494 
495 void
496 aes_xts_crypt(struct aes_xts_ctx *ctx, u_int8_t *data, u_int do_encrypt)
497 {
498 	u_int8_t block[AES_XTS_BLOCKSIZE];
499 	u_int i, carry_in, carry_out;
500 
501 	for (i = 0; i < AES_XTS_BLOCKSIZE; i++)
502 		block[i] = data[i] ^ ctx->tweak[i];
503 
504 	if (do_encrypt)
505 		rijndael_encrypt(&ctx->key1, block, data);
506 	else
507 		rijndael_decrypt(&ctx->key1, block, data);
508 
509 	for (i = 0; i < AES_XTS_BLOCKSIZE; i++)
510 		data[i] ^= ctx->tweak[i];
511 
512 	/* Exponentiate tweak */
513 	carry_in = 0;
514 	for (i = 0; i < AES_XTS_BLOCKSIZE; i++) {
515 		carry_out = ctx->tweak[i] & 0x80;
516 		ctx->tweak[i] = (ctx->tweak[i] << 1) | carry_in;
517 		carry_in = carry_out >> 7;
518 	}
519 	ctx->tweak[0] ^= (AES_XTS_ALPHA & -carry_in);
520 	explicit_bzero(block, sizeof(block));
521 }
522 
523 void
524 aes_xts_encrypt(caddr_t key, u_int8_t *data)
525 {
526 	aes_xts_crypt((struct aes_xts_ctx *)key, data, 1);
527 }
528 
529 void
530 aes_xts_decrypt(caddr_t key, u_int8_t *data)
531 {
532 	aes_xts_crypt((struct aes_xts_ctx *)key, data, 0);
533 }
534 
535 int
536 aes_xts_setkey(void *sched, u_int8_t *key, int len)
537 {
538 	struct aes_xts_ctx *ctx;
539 
540 	if (len != 32 && len != 64)
541 		return -1;
542 
543 	ctx = (struct aes_xts_ctx *)sched;
544 
545 	rijndael_set_key(&ctx->key1, key, len * 4);
546 	rijndael_set_key(&ctx->key2, key + (len / 2), len * 4);
547 
548 	return 0;
549 }
550 
551 /*
552  * And now for auth.
553  */
554 
555 int
556 RMD160Update_int(void *ctx, const u_int8_t *buf, u_int16_t len)
557 {
558 	RMD160Update(ctx, buf, len);
559 	return 0;
560 }
561 
562 int
563 MD5Update_int(void *ctx, const u_int8_t *buf, u_int16_t len)
564 {
565 	MD5Update(ctx, buf, len);
566 	return 0;
567 }
568 
569 int
570 SHA1Update_int(void *ctx, const u_int8_t *buf, u_int16_t len)
571 {
572 	SHA1Update(ctx, buf, len);
573 	return 0;
574 }
575 
576 int
577 SHA256Update_int(void *ctx, const u_int8_t *buf, u_int16_t len)
578 {
579 	SHA256Update(ctx, buf, len);
580 	return 0;
581 }
582 
583 int
584 SHA384Update_int(void *ctx, const u_int8_t *buf, u_int16_t len)
585 {
586 	SHA384Update(ctx, buf, len);
587 	return 0;
588 }
589 
590 int
591 SHA512Update_int(void *ctx, const u_int8_t *buf, u_int16_t len)
592 {
593 	SHA512Update(ctx, buf, len);
594 	return 0;
595 }
596 
597 
598 u_int32_t deflate_global(u_int8_t *, u_int32_t, int, u_int8_t **);
599 
600 struct deflate_buf {
601         u_int8_t *out;
602         u_int32_t size;
603         int flag;
604 };
605 
606 /*
607  * And compression
608  */
609 
610 u_int32_t
611 deflate_compress(u_int8_t *data, u_int32_t size, u_int8_t **out)
612 {
613 	return deflate_global(data, size, 0, out);
614 }
615 
616 u_int32_t
617 deflate_decompress(u_int8_t *data, u_int32_t size, u_int8_t **out)
618 {
619 	return deflate_global(data, size, 1, out);
620 }
621 
622 u_int32_t
623 lzs_dummy(u_int8_t *data, u_int32_t size, u_int8_t **out)
624 {
625 	*out = NULL;
626 	return (0);
627 }
628