xref: /openbmc/linux/crypto/ccm.c (revision dc6a81c3)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * CCM: Counter with CBC-MAC
4  *
5  * (C) Copyright IBM Corp. 2007 - Joy Latten <latten@us.ibm.com>
6  */
7 
8 #include <crypto/internal/aead.h>
9 #include <crypto/internal/hash.h>
10 #include <crypto/internal/skcipher.h>
11 #include <crypto/scatterwalk.h>
12 #include <linux/err.h>
13 #include <linux/init.h>
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/slab.h>
17 
18 struct ccm_instance_ctx {
19 	struct crypto_skcipher_spawn ctr;
20 	struct crypto_ahash_spawn mac;
21 };
22 
23 struct crypto_ccm_ctx {
24 	struct crypto_ahash *mac;
25 	struct crypto_skcipher *ctr;
26 };
27 
28 struct crypto_rfc4309_ctx {
29 	struct crypto_aead *child;
30 	u8 nonce[3];
31 };
32 
33 struct crypto_rfc4309_req_ctx {
34 	struct scatterlist src[3];
35 	struct scatterlist dst[3];
36 	struct aead_request subreq;
37 };
38 
39 struct crypto_ccm_req_priv_ctx {
40 	u8 odata[16];
41 	u8 idata[16];
42 	u8 auth_tag[16];
43 	u32 flags;
44 	struct scatterlist src[3];
45 	struct scatterlist dst[3];
46 	union {
47 		struct ahash_request ahreq;
48 		struct skcipher_request skreq;
49 	};
50 };
51 
52 struct cbcmac_tfm_ctx {
53 	struct crypto_cipher *child;
54 };
55 
56 struct cbcmac_desc_ctx {
57 	unsigned int len;
58 };
59 
60 static inline struct crypto_ccm_req_priv_ctx *crypto_ccm_reqctx(
61 	struct aead_request *req)
62 {
63 	unsigned long align = crypto_aead_alignmask(crypto_aead_reqtfm(req));
64 
65 	return (void *)PTR_ALIGN((u8 *)aead_request_ctx(req), align + 1);
66 }
67 
68 static int set_msg_len(u8 *block, unsigned int msglen, int csize)
69 {
70 	__be32 data;
71 
72 	memset(block, 0, csize);
73 	block += csize;
74 
75 	if (csize >= 4)
76 		csize = 4;
77 	else if (msglen > (1 << (8 * csize)))
78 		return -EOVERFLOW;
79 
80 	data = cpu_to_be32(msglen);
81 	memcpy(block - csize, (u8 *)&data + 4 - csize, csize);
82 
83 	return 0;
84 }
85 
86 static int crypto_ccm_setkey(struct crypto_aead *aead, const u8 *key,
87 			     unsigned int keylen)
88 {
89 	struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
90 	struct crypto_skcipher *ctr = ctx->ctr;
91 	struct crypto_ahash *mac = ctx->mac;
92 	int err;
93 
94 	crypto_skcipher_clear_flags(ctr, CRYPTO_TFM_REQ_MASK);
95 	crypto_skcipher_set_flags(ctr, crypto_aead_get_flags(aead) &
96 				       CRYPTO_TFM_REQ_MASK);
97 	err = crypto_skcipher_setkey(ctr, key, keylen);
98 	if (err)
99 		return err;
100 
101 	crypto_ahash_clear_flags(mac, CRYPTO_TFM_REQ_MASK);
102 	crypto_ahash_set_flags(mac, crypto_aead_get_flags(aead) &
103 				    CRYPTO_TFM_REQ_MASK);
104 	return crypto_ahash_setkey(mac, key, keylen);
105 }
106 
107 static int crypto_ccm_setauthsize(struct crypto_aead *tfm,
108 				  unsigned int authsize)
109 {
110 	switch (authsize) {
111 	case 4:
112 	case 6:
113 	case 8:
114 	case 10:
115 	case 12:
116 	case 14:
117 	case 16:
118 		break;
119 	default:
120 		return -EINVAL;
121 	}
122 
123 	return 0;
124 }
125 
126 static int format_input(u8 *info, struct aead_request *req,
127 			unsigned int cryptlen)
128 {
129 	struct crypto_aead *aead = crypto_aead_reqtfm(req);
130 	unsigned int lp = req->iv[0];
131 	unsigned int l = lp + 1;
132 	unsigned int m;
133 
134 	m = crypto_aead_authsize(aead);
135 
136 	memcpy(info, req->iv, 16);
137 
138 	/* format control info per RFC 3610 and
139 	 * NIST Special Publication 800-38C
140 	 */
141 	*info |= (8 * ((m - 2) / 2));
142 	if (req->assoclen)
143 		*info |= 64;
144 
145 	return set_msg_len(info + 16 - l, cryptlen, l);
146 }
147 
148 static int format_adata(u8 *adata, unsigned int a)
149 {
150 	int len = 0;
151 
152 	/* add control info for associated data
153 	 * RFC 3610 and NIST Special Publication 800-38C
154 	 */
155 	if (a < 65280) {
156 		*(__be16 *)adata = cpu_to_be16(a);
157 		len = 2;
158 	} else  {
159 		*(__be16 *)adata = cpu_to_be16(0xfffe);
160 		*(__be32 *)&adata[2] = cpu_to_be32(a);
161 		len = 6;
162 	}
163 
164 	return len;
165 }
166 
167 static int crypto_ccm_auth(struct aead_request *req, struct scatterlist *plain,
168 			   unsigned int cryptlen)
169 {
170 	struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
171 	struct crypto_aead *aead = crypto_aead_reqtfm(req);
172 	struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
173 	struct ahash_request *ahreq = &pctx->ahreq;
174 	unsigned int assoclen = req->assoclen;
175 	struct scatterlist sg[3];
176 	u8 *odata = pctx->odata;
177 	u8 *idata = pctx->idata;
178 	int ilen, err;
179 
180 	/* format control data for input */
181 	err = format_input(odata, req, cryptlen);
182 	if (err)
183 		goto out;
184 
185 	sg_init_table(sg, 3);
186 	sg_set_buf(&sg[0], odata, 16);
187 
188 	/* format associated data and compute into mac */
189 	if (assoclen) {
190 		ilen = format_adata(idata, assoclen);
191 		sg_set_buf(&sg[1], idata, ilen);
192 		sg_chain(sg, 3, req->src);
193 	} else {
194 		ilen = 0;
195 		sg_chain(sg, 2, req->src);
196 	}
197 
198 	ahash_request_set_tfm(ahreq, ctx->mac);
199 	ahash_request_set_callback(ahreq, pctx->flags, NULL, NULL);
200 	ahash_request_set_crypt(ahreq, sg, NULL, assoclen + ilen + 16);
201 	err = crypto_ahash_init(ahreq);
202 	if (err)
203 		goto out;
204 	err = crypto_ahash_update(ahreq);
205 	if (err)
206 		goto out;
207 
208 	/* we need to pad the MAC input to a round multiple of the block size */
209 	ilen = 16 - (assoclen + ilen) % 16;
210 	if (ilen < 16) {
211 		memset(idata, 0, ilen);
212 		sg_init_table(sg, 2);
213 		sg_set_buf(&sg[0], idata, ilen);
214 		if (plain)
215 			sg_chain(sg, 2, plain);
216 		plain = sg;
217 		cryptlen += ilen;
218 	}
219 
220 	ahash_request_set_crypt(ahreq, plain, pctx->odata, cryptlen);
221 	err = crypto_ahash_finup(ahreq);
222 out:
223 	return err;
224 }
225 
226 static void crypto_ccm_encrypt_done(struct crypto_async_request *areq, int err)
227 {
228 	struct aead_request *req = areq->data;
229 	struct crypto_aead *aead = crypto_aead_reqtfm(req);
230 	struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
231 	u8 *odata = pctx->odata;
232 
233 	if (!err)
234 		scatterwalk_map_and_copy(odata, req->dst,
235 					 req->assoclen + req->cryptlen,
236 					 crypto_aead_authsize(aead), 1);
237 	aead_request_complete(req, err);
238 }
239 
240 static inline int crypto_ccm_check_iv(const u8 *iv)
241 {
242 	/* 2 <= L <= 8, so 1 <= L' <= 7. */
243 	if (1 > iv[0] || iv[0] > 7)
244 		return -EINVAL;
245 
246 	return 0;
247 }
248 
249 static int crypto_ccm_init_crypt(struct aead_request *req, u8 *tag)
250 {
251 	struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
252 	struct scatterlist *sg;
253 	u8 *iv = req->iv;
254 	int err;
255 
256 	err = crypto_ccm_check_iv(iv);
257 	if (err)
258 		return err;
259 
260 	pctx->flags = aead_request_flags(req);
261 
262 	 /* Note: rfc 3610 and NIST 800-38C require counter of
263 	 * zero to encrypt auth tag.
264 	 */
265 	memset(iv + 15 - iv[0], 0, iv[0] + 1);
266 
267 	sg_init_table(pctx->src, 3);
268 	sg_set_buf(pctx->src, tag, 16);
269 	sg = scatterwalk_ffwd(pctx->src + 1, req->src, req->assoclen);
270 	if (sg != pctx->src + 1)
271 		sg_chain(pctx->src, 2, sg);
272 
273 	if (req->src != req->dst) {
274 		sg_init_table(pctx->dst, 3);
275 		sg_set_buf(pctx->dst, tag, 16);
276 		sg = scatterwalk_ffwd(pctx->dst + 1, req->dst, req->assoclen);
277 		if (sg != pctx->dst + 1)
278 			sg_chain(pctx->dst, 2, sg);
279 	}
280 
281 	return 0;
282 }
283 
284 static int crypto_ccm_encrypt(struct aead_request *req)
285 {
286 	struct crypto_aead *aead = crypto_aead_reqtfm(req);
287 	struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
288 	struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
289 	struct skcipher_request *skreq = &pctx->skreq;
290 	struct scatterlist *dst;
291 	unsigned int cryptlen = req->cryptlen;
292 	u8 *odata = pctx->odata;
293 	u8 *iv = req->iv;
294 	int err;
295 
296 	err = crypto_ccm_init_crypt(req, odata);
297 	if (err)
298 		return err;
299 
300 	err = crypto_ccm_auth(req, sg_next(pctx->src), cryptlen);
301 	if (err)
302 		return err;
303 
304 	dst = pctx->src;
305 	if (req->src != req->dst)
306 		dst = pctx->dst;
307 
308 	skcipher_request_set_tfm(skreq, ctx->ctr);
309 	skcipher_request_set_callback(skreq, pctx->flags,
310 				      crypto_ccm_encrypt_done, req);
311 	skcipher_request_set_crypt(skreq, pctx->src, dst, cryptlen + 16, iv);
312 	err = crypto_skcipher_encrypt(skreq);
313 	if (err)
314 		return err;
315 
316 	/* copy authtag to end of dst */
317 	scatterwalk_map_and_copy(odata, sg_next(dst), cryptlen,
318 				 crypto_aead_authsize(aead), 1);
319 	return err;
320 }
321 
322 static void crypto_ccm_decrypt_done(struct crypto_async_request *areq,
323 				   int err)
324 {
325 	struct aead_request *req = areq->data;
326 	struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
327 	struct crypto_aead *aead = crypto_aead_reqtfm(req);
328 	unsigned int authsize = crypto_aead_authsize(aead);
329 	unsigned int cryptlen = req->cryptlen - authsize;
330 	struct scatterlist *dst;
331 
332 	pctx->flags = 0;
333 
334 	dst = sg_next(req->src == req->dst ? pctx->src : pctx->dst);
335 
336 	if (!err) {
337 		err = crypto_ccm_auth(req, dst, cryptlen);
338 		if (!err && crypto_memneq(pctx->auth_tag, pctx->odata, authsize))
339 			err = -EBADMSG;
340 	}
341 	aead_request_complete(req, err);
342 }
343 
344 static int crypto_ccm_decrypt(struct aead_request *req)
345 {
346 	struct crypto_aead *aead = crypto_aead_reqtfm(req);
347 	struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
348 	struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
349 	struct skcipher_request *skreq = &pctx->skreq;
350 	struct scatterlist *dst;
351 	unsigned int authsize = crypto_aead_authsize(aead);
352 	unsigned int cryptlen = req->cryptlen;
353 	u8 *authtag = pctx->auth_tag;
354 	u8 *odata = pctx->odata;
355 	u8 *iv = pctx->idata;
356 	int err;
357 
358 	cryptlen -= authsize;
359 
360 	err = crypto_ccm_init_crypt(req, authtag);
361 	if (err)
362 		return err;
363 
364 	scatterwalk_map_and_copy(authtag, sg_next(pctx->src), cryptlen,
365 				 authsize, 0);
366 
367 	dst = pctx->src;
368 	if (req->src != req->dst)
369 		dst = pctx->dst;
370 
371 	memcpy(iv, req->iv, 16);
372 
373 	skcipher_request_set_tfm(skreq, ctx->ctr);
374 	skcipher_request_set_callback(skreq, pctx->flags,
375 				      crypto_ccm_decrypt_done, req);
376 	skcipher_request_set_crypt(skreq, pctx->src, dst, cryptlen + 16, iv);
377 	err = crypto_skcipher_decrypt(skreq);
378 	if (err)
379 		return err;
380 
381 	err = crypto_ccm_auth(req, sg_next(dst), cryptlen);
382 	if (err)
383 		return err;
384 
385 	/* verify */
386 	if (crypto_memneq(authtag, odata, authsize))
387 		return -EBADMSG;
388 
389 	return err;
390 }
391 
392 static int crypto_ccm_init_tfm(struct crypto_aead *tfm)
393 {
394 	struct aead_instance *inst = aead_alg_instance(tfm);
395 	struct ccm_instance_ctx *ictx = aead_instance_ctx(inst);
396 	struct crypto_ccm_ctx *ctx = crypto_aead_ctx(tfm);
397 	struct crypto_ahash *mac;
398 	struct crypto_skcipher *ctr;
399 	unsigned long align;
400 	int err;
401 
402 	mac = crypto_spawn_ahash(&ictx->mac);
403 	if (IS_ERR(mac))
404 		return PTR_ERR(mac);
405 
406 	ctr = crypto_spawn_skcipher(&ictx->ctr);
407 	err = PTR_ERR(ctr);
408 	if (IS_ERR(ctr))
409 		goto err_free_mac;
410 
411 	ctx->mac = mac;
412 	ctx->ctr = ctr;
413 
414 	align = crypto_aead_alignmask(tfm);
415 	align &= ~(crypto_tfm_ctx_alignment() - 1);
416 	crypto_aead_set_reqsize(
417 		tfm,
418 		align + sizeof(struct crypto_ccm_req_priv_ctx) +
419 		max(crypto_ahash_reqsize(mac), crypto_skcipher_reqsize(ctr)));
420 
421 	return 0;
422 
423 err_free_mac:
424 	crypto_free_ahash(mac);
425 	return err;
426 }
427 
428 static void crypto_ccm_exit_tfm(struct crypto_aead *tfm)
429 {
430 	struct crypto_ccm_ctx *ctx = crypto_aead_ctx(tfm);
431 
432 	crypto_free_ahash(ctx->mac);
433 	crypto_free_skcipher(ctx->ctr);
434 }
435 
436 static void crypto_ccm_free(struct aead_instance *inst)
437 {
438 	struct ccm_instance_ctx *ctx = aead_instance_ctx(inst);
439 
440 	crypto_drop_ahash(&ctx->mac);
441 	crypto_drop_skcipher(&ctx->ctr);
442 	kfree(inst);
443 }
444 
445 static int crypto_ccm_create_common(struct crypto_template *tmpl,
446 				    struct rtattr **tb,
447 				    const char *ctr_name,
448 				    const char *mac_name)
449 {
450 	struct crypto_attr_type *algt;
451 	u32 mask;
452 	struct aead_instance *inst;
453 	struct ccm_instance_ctx *ictx;
454 	struct skcipher_alg *ctr;
455 	struct hash_alg_common *mac;
456 	int err;
457 
458 	algt = crypto_get_attr_type(tb);
459 	if (IS_ERR(algt))
460 		return PTR_ERR(algt);
461 
462 	if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
463 		return -EINVAL;
464 
465 	mask = crypto_requires_sync(algt->type, algt->mask);
466 
467 	inst = kzalloc(sizeof(*inst) + sizeof(*ictx), GFP_KERNEL);
468 	if (!inst)
469 		return -ENOMEM;
470 	ictx = aead_instance_ctx(inst);
471 
472 	err = crypto_grab_ahash(&ictx->mac, aead_crypto_instance(inst),
473 				mac_name, 0, CRYPTO_ALG_ASYNC);
474 	if (err)
475 		goto err_free_inst;
476 	mac = crypto_spawn_ahash_alg(&ictx->mac);
477 
478 	err = -EINVAL;
479 	if (strncmp(mac->base.cra_name, "cbcmac(", 7) != 0 ||
480 	    mac->digestsize != 16)
481 		goto err_free_inst;
482 
483 	err = crypto_grab_skcipher(&ictx->ctr, aead_crypto_instance(inst),
484 				   ctr_name, 0, mask);
485 	if (err)
486 		goto err_free_inst;
487 	ctr = crypto_spawn_skcipher_alg(&ictx->ctr);
488 
489 	/* The skcipher algorithm must be CTR mode, using 16-byte blocks. */
490 	err = -EINVAL;
491 	if (strncmp(ctr->base.cra_name, "ctr(", 4) != 0 ||
492 	    crypto_skcipher_alg_ivsize(ctr) != 16 ||
493 	    ctr->base.cra_blocksize != 1)
494 		goto err_free_inst;
495 
496 	/* ctr and cbcmac must use the same underlying block cipher. */
497 	if (strcmp(ctr->base.cra_name + 4, mac->base.cra_name + 7) != 0)
498 		goto err_free_inst;
499 
500 	err = -ENAMETOOLONG;
501 	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
502 		     "ccm(%s", ctr->base.cra_name + 4) >= CRYPTO_MAX_ALG_NAME)
503 		goto err_free_inst;
504 
505 	if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
506 		     "ccm_base(%s,%s)", ctr->base.cra_driver_name,
507 		     mac->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
508 		goto err_free_inst;
509 
510 	inst->alg.base.cra_flags = ctr->base.cra_flags & CRYPTO_ALG_ASYNC;
511 	inst->alg.base.cra_priority = (mac->base.cra_priority +
512 				       ctr->base.cra_priority) / 2;
513 	inst->alg.base.cra_blocksize = 1;
514 	inst->alg.base.cra_alignmask = mac->base.cra_alignmask |
515 				       ctr->base.cra_alignmask;
516 	inst->alg.ivsize = 16;
517 	inst->alg.chunksize = crypto_skcipher_alg_chunksize(ctr);
518 	inst->alg.maxauthsize = 16;
519 	inst->alg.base.cra_ctxsize = sizeof(struct crypto_ccm_ctx);
520 	inst->alg.init = crypto_ccm_init_tfm;
521 	inst->alg.exit = crypto_ccm_exit_tfm;
522 	inst->alg.setkey = crypto_ccm_setkey;
523 	inst->alg.setauthsize = crypto_ccm_setauthsize;
524 	inst->alg.encrypt = crypto_ccm_encrypt;
525 	inst->alg.decrypt = crypto_ccm_decrypt;
526 
527 	inst->free = crypto_ccm_free;
528 
529 	err = aead_register_instance(tmpl, inst);
530 	if (err) {
531 err_free_inst:
532 		crypto_ccm_free(inst);
533 	}
534 	return err;
535 }
536 
537 static int crypto_ccm_create(struct crypto_template *tmpl, struct rtattr **tb)
538 {
539 	const char *cipher_name;
540 	char ctr_name[CRYPTO_MAX_ALG_NAME];
541 	char mac_name[CRYPTO_MAX_ALG_NAME];
542 
543 	cipher_name = crypto_attr_alg_name(tb[1]);
544 	if (IS_ERR(cipher_name))
545 		return PTR_ERR(cipher_name);
546 
547 	if (snprintf(ctr_name, CRYPTO_MAX_ALG_NAME, "ctr(%s)",
548 		     cipher_name) >= CRYPTO_MAX_ALG_NAME)
549 		return -ENAMETOOLONG;
550 
551 	if (snprintf(mac_name, CRYPTO_MAX_ALG_NAME, "cbcmac(%s)",
552 		     cipher_name) >= CRYPTO_MAX_ALG_NAME)
553 		return -ENAMETOOLONG;
554 
555 	return crypto_ccm_create_common(tmpl, tb, ctr_name, mac_name);
556 }
557 
558 static int crypto_ccm_base_create(struct crypto_template *tmpl,
559 				  struct rtattr **tb)
560 {
561 	const char *ctr_name;
562 	const char *mac_name;
563 
564 	ctr_name = crypto_attr_alg_name(tb[1]);
565 	if (IS_ERR(ctr_name))
566 		return PTR_ERR(ctr_name);
567 
568 	mac_name = crypto_attr_alg_name(tb[2]);
569 	if (IS_ERR(mac_name))
570 		return PTR_ERR(mac_name);
571 
572 	return crypto_ccm_create_common(tmpl, tb, ctr_name, mac_name);
573 }
574 
575 static int crypto_rfc4309_setkey(struct crypto_aead *parent, const u8 *key,
576 				 unsigned int keylen)
577 {
578 	struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(parent);
579 	struct crypto_aead *child = ctx->child;
580 
581 	if (keylen < 3)
582 		return -EINVAL;
583 
584 	keylen -= 3;
585 	memcpy(ctx->nonce, key + keylen, 3);
586 
587 	crypto_aead_clear_flags(child, CRYPTO_TFM_REQ_MASK);
588 	crypto_aead_set_flags(child, crypto_aead_get_flags(parent) &
589 				     CRYPTO_TFM_REQ_MASK);
590 	return crypto_aead_setkey(child, key, keylen);
591 }
592 
593 static int crypto_rfc4309_setauthsize(struct crypto_aead *parent,
594 				      unsigned int authsize)
595 {
596 	struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(parent);
597 
598 	switch (authsize) {
599 	case 8:
600 	case 12:
601 	case 16:
602 		break;
603 	default:
604 		return -EINVAL;
605 	}
606 
607 	return crypto_aead_setauthsize(ctx->child, authsize);
608 }
609 
610 static struct aead_request *crypto_rfc4309_crypt(struct aead_request *req)
611 {
612 	struct crypto_rfc4309_req_ctx *rctx = aead_request_ctx(req);
613 	struct aead_request *subreq = &rctx->subreq;
614 	struct crypto_aead *aead = crypto_aead_reqtfm(req);
615 	struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(aead);
616 	struct crypto_aead *child = ctx->child;
617 	struct scatterlist *sg;
618 	u8 *iv = PTR_ALIGN((u8 *)(subreq + 1) + crypto_aead_reqsize(child),
619 			   crypto_aead_alignmask(child) + 1);
620 
621 	/* L' */
622 	iv[0] = 3;
623 
624 	memcpy(iv + 1, ctx->nonce, 3);
625 	memcpy(iv + 4, req->iv, 8);
626 
627 	scatterwalk_map_and_copy(iv + 16, req->src, 0, req->assoclen - 8, 0);
628 
629 	sg_init_table(rctx->src, 3);
630 	sg_set_buf(rctx->src, iv + 16, req->assoclen - 8);
631 	sg = scatterwalk_ffwd(rctx->src + 1, req->src, req->assoclen);
632 	if (sg != rctx->src + 1)
633 		sg_chain(rctx->src, 2, sg);
634 
635 	if (req->src != req->dst) {
636 		sg_init_table(rctx->dst, 3);
637 		sg_set_buf(rctx->dst, iv + 16, req->assoclen - 8);
638 		sg = scatterwalk_ffwd(rctx->dst + 1, req->dst, req->assoclen);
639 		if (sg != rctx->dst + 1)
640 			sg_chain(rctx->dst, 2, sg);
641 	}
642 
643 	aead_request_set_tfm(subreq, child);
644 	aead_request_set_callback(subreq, req->base.flags, req->base.complete,
645 				  req->base.data);
646 	aead_request_set_crypt(subreq, rctx->src,
647 			       req->src == req->dst ? rctx->src : rctx->dst,
648 			       req->cryptlen, iv);
649 	aead_request_set_ad(subreq, req->assoclen - 8);
650 
651 	return subreq;
652 }
653 
654 static int crypto_rfc4309_encrypt(struct aead_request *req)
655 {
656 	if (req->assoclen != 16 && req->assoclen != 20)
657 		return -EINVAL;
658 
659 	req = crypto_rfc4309_crypt(req);
660 
661 	return crypto_aead_encrypt(req);
662 }
663 
664 static int crypto_rfc4309_decrypt(struct aead_request *req)
665 {
666 	if (req->assoclen != 16 && req->assoclen != 20)
667 		return -EINVAL;
668 
669 	req = crypto_rfc4309_crypt(req);
670 
671 	return crypto_aead_decrypt(req);
672 }
673 
674 static int crypto_rfc4309_init_tfm(struct crypto_aead *tfm)
675 {
676 	struct aead_instance *inst = aead_alg_instance(tfm);
677 	struct crypto_aead_spawn *spawn = aead_instance_ctx(inst);
678 	struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(tfm);
679 	struct crypto_aead *aead;
680 	unsigned long align;
681 
682 	aead = crypto_spawn_aead(spawn);
683 	if (IS_ERR(aead))
684 		return PTR_ERR(aead);
685 
686 	ctx->child = aead;
687 
688 	align = crypto_aead_alignmask(aead);
689 	align &= ~(crypto_tfm_ctx_alignment() - 1);
690 	crypto_aead_set_reqsize(
691 		tfm,
692 		sizeof(struct crypto_rfc4309_req_ctx) +
693 		ALIGN(crypto_aead_reqsize(aead), crypto_tfm_ctx_alignment()) +
694 		align + 32);
695 
696 	return 0;
697 }
698 
699 static void crypto_rfc4309_exit_tfm(struct crypto_aead *tfm)
700 {
701 	struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(tfm);
702 
703 	crypto_free_aead(ctx->child);
704 }
705 
706 static void crypto_rfc4309_free(struct aead_instance *inst)
707 {
708 	crypto_drop_aead(aead_instance_ctx(inst));
709 	kfree(inst);
710 }
711 
712 static int crypto_rfc4309_create(struct crypto_template *tmpl,
713 				 struct rtattr **tb)
714 {
715 	struct crypto_attr_type *algt;
716 	u32 mask;
717 	struct aead_instance *inst;
718 	struct crypto_aead_spawn *spawn;
719 	struct aead_alg *alg;
720 	const char *ccm_name;
721 	int err;
722 
723 	algt = crypto_get_attr_type(tb);
724 	if (IS_ERR(algt))
725 		return PTR_ERR(algt);
726 
727 	if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
728 		return -EINVAL;
729 
730 	mask = crypto_requires_sync(algt->type, algt->mask);
731 
732 	ccm_name = crypto_attr_alg_name(tb[1]);
733 	if (IS_ERR(ccm_name))
734 		return PTR_ERR(ccm_name);
735 
736 	inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
737 	if (!inst)
738 		return -ENOMEM;
739 
740 	spawn = aead_instance_ctx(inst);
741 	err = crypto_grab_aead(spawn, aead_crypto_instance(inst),
742 			       ccm_name, 0, mask);
743 	if (err)
744 		goto out_free_inst;
745 
746 	alg = crypto_spawn_aead_alg(spawn);
747 
748 	err = -EINVAL;
749 
750 	/* We only support 16-byte blocks. */
751 	if (crypto_aead_alg_ivsize(alg) != 16)
752 		goto out_drop_alg;
753 
754 	/* Not a stream cipher? */
755 	if (alg->base.cra_blocksize != 1)
756 		goto out_drop_alg;
757 
758 	err = -ENAMETOOLONG;
759 	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
760 		     "rfc4309(%s)", alg->base.cra_name) >=
761 	    CRYPTO_MAX_ALG_NAME ||
762 	    snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
763 		     "rfc4309(%s)", alg->base.cra_driver_name) >=
764 	    CRYPTO_MAX_ALG_NAME)
765 		goto out_drop_alg;
766 
767 	inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
768 	inst->alg.base.cra_priority = alg->base.cra_priority;
769 	inst->alg.base.cra_blocksize = 1;
770 	inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
771 
772 	inst->alg.ivsize = 8;
773 	inst->alg.chunksize = crypto_aead_alg_chunksize(alg);
774 	inst->alg.maxauthsize = 16;
775 
776 	inst->alg.base.cra_ctxsize = sizeof(struct crypto_rfc4309_ctx);
777 
778 	inst->alg.init = crypto_rfc4309_init_tfm;
779 	inst->alg.exit = crypto_rfc4309_exit_tfm;
780 
781 	inst->alg.setkey = crypto_rfc4309_setkey;
782 	inst->alg.setauthsize = crypto_rfc4309_setauthsize;
783 	inst->alg.encrypt = crypto_rfc4309_encrypt;
784 	inst->alg.decrypt = crypto_rfc4309_decrypt;
785 
786 	inst->free = crypto_rfc4309_free;
787 
788 	err = aead_register_instance(tmpl, inst);
789 	if (err)
790 		goto out_drop_alg;
791 
792 out:
793 	return err;
794 
795 out_drop_alg:
796 	crypto_drop_aead(spawn);
797 out_free_inst:
798 	kfree(inst);
799 	goto out;
800 }
801 
802 static int crypto_cbcmac_digest_setkey(struct crypto_shash *parent,
803 				     const u8 *inkey, unsigned int keylen)
804 {
805 	struct cbcmac_tfm_ctx *ctx = crypto_shash_ctx(parent);
806 
807 	return crypto_cipher_setkey(ctx->child, inkey, keylen);
808 }
809 
810 static int crypto_cbcmac_digest_init(struct shash_desc *pdesc)
811 {
812 	struct cbcmac_desc_ctx *ctx = shash_desc_ctx(pdesc);
813 	int bs = crypto_shash_digestsize(pdesc->tfm);
814 	u8 *dg = (u8 *)ctx + crypto_shash_descsize(pdesc->tfm) - bs;
815 
816 	ctx->len = 0;
817 	memset(dg, 0, bs);
818 
819 	return 0;
820 }
821 
822 static int crypto_cbcmac_digest_update(struct shash_desc *pdesc, const u8 *p,
823 				       unsigned int len)
824 {
825 	struct crypto_shash *parent = pdesc->tfm;
826 	struct cbcmac_tfm_ctx *tctx = crypto_shash_ctx(parent);
827 	struct cbcmac_desc_ctx *ctx = shash_desc_ctx(pdesc);
828 	struct crypto_cipher *tfm = tctx->child;
829 	int bs = crypto_shash_digestsize(parent);
830 	u8 *dg = (u8 *)ctx + crypto_shash_descsize(parent) - bs;
831 
832 	while (len > 0) {
833 		unsigned int l = min(len, bs - ctx->len);
834 
835 		crypto_xor(dg + ctx->len, p, l);
836 		ctx->len +=l;
837 		len -= l;
838 		p += l;
839 
840 		if (ctx->len == bs) {
841 			crypto_cipher_encrypt_one(tfm, dg, dg);
842 			ctx->len = 0;
843 		}
844 	}
845 
846 	return 0;
847 }
848 
849 static int crypto_cbcmac_digest_final(struct shash_desc *pdesc, u8 *out)
850 {
851 	struct crypto_shash *parent = pdesc->tfm;
852 	struct cbcmac_tfm_ctx *tctx = crypto_shash_ctx(parent);
853 	struct cbcmac_desc_ctx *ctx = shash_desc_ctx(pdesc);
854 	struct crypto_cipher *tfm = tctx->child;
855 	int bs = crypto_shash_digestsize(parent);
856 	u8 *dg = (u8 *)ctx + crypto_shash_descsize(parent) - bs;
857 
858 	if (ctx->len)
859 		crypto_cipher_encrypt_one(tfm, dg, dg);
860 
861 	memcpy(out, dg, bs);
862 	return 0;
863 }
864 
865 static int cbcmac_init_tfm(struct crypto_tfm *tfm)
866 {
867 	struct crypto_cipher *cipher;
868 	struct crypto_instance *inst = (void *)tfm->__crt_alg;
869 	struct crypto_cipher_spawn *spawn = crypto_instance_ctx(inst);
870 	struct cbcmac_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
871 
872 	cipher = crypto_spawn_cipher(spawn);
873 	if (IS_ERR(cipher))
874 		return PTR_ERR(cipher);
875 
876 	ctx->child = cipher;
877 
878 	return 0;
879 };
880 
881 static void cbcmac_exit_tfm(struct crypto_tfm *tfm)
882 {
883 	struct cbcmac_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
884 	crypto_free_cipher(ctx->child);
885 }
886 
887 static int cbcmac_create(struct crypto_template *tmpl, struct rtattr **tb)
888 {
889 	struct shash_instance *inst;
890 	struct crypto_cipher_spawn *spawn;
891 	struct crypto_alg *alg;
892 	int err;
893 
894 	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH);
895 	if (err)
896 		return err;
897 
898 	inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
899 	if (!inst)
900 		return -ENOMEM;
901 	spawn = shash_instance_ctx(inst);
902 
903 	err = crypto_grab_cipher(spawn, shash_crypto_instance(inst),
904 				 crypto_attr_alg_name(tb[1]), 0, 0);
905 	if (err)
906 		goto err_free_inst;
907 	alg = crypto_spawn_cipher_alg(spawn);
908 
909 	err = crypto_inst_setname(shash_crypto_instance(inst), tmpl->name, alg);
910 	if (err)
911 		goto err_free_inst;
912 
913 	inst->alg.base.cra_priority = alg->cra_priority;
914 	inst->alg.base.cra_blocksize = 1;
915 
916 	inst->alg.digestsize = alg->cra_blocksize;
917 	inst->alg.descsize = ALIGN(sizeof(struct cbcmac_desc_ctx),
918 				   alg->cra_alignmask + 1) +
919 			     alg->cra_blocksize;
920 
921 	inst->alg.base.cra_ctxsize = sizeof(struct cbcmac_tfm_ctx);
922 	inst->alg.base.cra_init = cbcmac_init_tfm;
923 	inst->alg.base.cra_exit = cbcmac_exit_tfm;
924 
925 	inst->alg.init = crypto_cbcmac_digest_init;
926 	inst->alg.update = crypto_cbcmac_digest_update;
927 	inst->alg.final = crypto_cbcmac_digest_final;
928 	inst->alg.setkey = crypto_cbcmac_digest_setkey;
929 
930 	inst->free = shash_free_singlespawn_instance;
931 
932 	err = shash_register_instance(tmpl, inst);
933 	if (err) {
934 err_free_inst:
935 		shash_free_singlespawn_instance(inst);
936 	}
937 	return err;
938 }
939 
940 static struct crypto_template crypto_ccm_tmpls[] = {
941 	{
942 		.name = "cbcmac",
943 		.create = cbcmac_create,
944 		.module = THIS_MODULE,
945 	}, {
946 		.name = "ccm_base",
947 		.create = crypto_ccm_base_create,
948 		.module = THIS_MODULE,
949 	}, {
950 		.name = "ccm",
951 		.create = crypto_ccm_create,
952 		.module = THIS_MODULE,
953 	}, {
954 		.name = "rfc4309",
955 		.create = crypto_rfc4309_create,
956 		.module = THIS_MODULE,
957 	},
958 };
959 
960 static int __init crypto_ccm_module_init(void)
961 {
962 	return crypto_register_templates(crypto_ccm_tmpls,
963 					 ARRAY_SIZE(crypto_ccm_tmpls));
964 }
965 
966 static void __exit crypto_ccm_module_exit(void)
967 {
968 	crypto_unregister_templates(crypto_ccm_tmpls,
969 				    ARRAY_SIZE(crypto_ccm_tmpls));
970 }
971 
972 subsys_initcall(crypto_ccm_module_init);
973 module_exit(crypto_ccm_module_exit);
974 
975 MODULE_LICENSE("GPL");
976 MODULE_DESCRIPTION("Counter with CBC MAC");
977 MODULE_ALIAS_CRYPTO("ccm_base");
978 MODULE_ALIAS_CRYPTO("rfc4309");
979 MODULE_ALIAS_CRYPTO("ccm");
980 MODULE_ALIAS_CRYPTO("cbcmac");
981