2 * GCM: Galois/Counter Mode.
4 * Copyright (c) 2007 Nokia Siemens Networks - Mikko Herranen <mh1@iki.fi>
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published
8 * by the Free Software Foundation.
11 #include <crypto/algapi.h>
12 #include <crypto/gf128mul.h>
13 #include <crypto/scatterwalk.h>
14 #include <linux/completion.h>
15 #include <linux/err.h>
16 #include <linux/init.h>
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/slab.h>
23 struct gcm_instance_ctx
{
24 struct crypto_spawn ctr
;
27 struct crypto_gcm_ctx
{
28 struct crypto_ablkcipher
*ctr
;
29 struct gf128mul_4k
*gf128
;
32 struct crypto_gcm_ghash_ctx
{
35 struct gf128mul_4k
*gf128
;
39 struct crypto_gcm_req_priv_ctx
{
42 struct scatterlist src
[2];
43 struct scatterlist dst
[2];
44 struct crypto_gcm_ghash_ctx ghash
;
45 struct ablkcipher_request abreq
;
48 struct crypto_gcm_setkey_result
{
50 struct completion completion
;
53 static inline struct crypto_gcm_req_priv_ctx
*crypto_gcm_reqctx(
54 struct aead_request
*req
)
56 unsigned long align
= crypto_aead_alignmask(crypto_aead_reqtfm(req
));
58 return (void *)PTR_ALIGN((u8
*)aead_request_ctx(req
), align
+ 1);
61 static void crypto_gcm_ghash_init(struct crypto_gcm_ghash_ctx
*ctx
, u32 flags
,
62 struct gf128mul_4k
*gf128
)
67 memset(ctx
->buffer
, 0, 16);
70 static void crypto_gcm_ghash_update(struct crypto_gcm_ghash_ctx
*ctx
,
71 const u8
*src
, unsigned int srclen
)
73 u8
*dst
= ctx
->buffer
;
76 int n
= min(srclen
, ctx
->bytes
);
77 u8
*pos
= dst
+ (16 - ctx
->bytes
);
86 gf128mul_4k_lle((be128
*)dst
, ctx
->gf128
);
89 while (srclen
>= 16) {
90 crypto_xor(dst
, src
, 16);
91 gf128mul_4k_lle((be128
*)dst
, ctx
->gf128
);
97 ctx
->bytes
= 16 - srclen
;
103 static void crypto_gcm_ghash_update_sg(struct crypto_gcm_ghash_ctx
*ctx
,
104 struct scatterlist
*sg
, int len
)
106 struct scatter_walk walk
;
113 scatterwalk_start(&walk
, sg
);
116 n
= scatterwalk_clamp(&walk
, len
);
119 scatterwalk_start(&walk
, scatterwalk_sg_next(walk
.sg
));
120 n
= scatterwalk_clamp(&walk
, len
);
123 src
= scatterwalk_map(&walk
, 0);
125 crypto_gcm_ghash_update(ctx
, src
, n
);
128 scatterwalk_unmap(src
, 0);
129 scatterwalk_advance(&walk
, n
);
130 scatterwalk_done(&walk
, 0, len
);
132 crypto_yield(ctx
->flags
);
136 static void crypto_gcm_ghash_flush(struct crypto_gcm_ghash_ctx
*ctx
)
138 u8
*dst
= ctx
->buffer
;
141 u8
*tmp
= dst
+ (16 - ctx
->bytes
);
146 gf128mul_4k_lle((be128
*)dst
, ctx
->gf128
);
152 static void crypto_gcm_ghash_final_xor(struct crypto_gcm_ghash_ctx
*ctx
,
153 unsigned int authlen
,
154 unsigned int cryptlen
, u8
*dst
)
156 u8
*buf
= ctx
->buffer
;
159 lengths
.a
= cpu_to_be64(authlen
* 8);
160 lengths
.b
= cpu_to_be64(cryptlen
* 8);
162 crypto_gcm_ghash_flush(ctx
);
163 crypto_xor(buf
, (u8
*)&lengths
, 16);
164 gf128mul_4k_lle((be128
*)buf
, ctx
->gf128
);
165 crypto_xor(dst
, buf
, 16);
168 static void crypto_gcm_setkey_done(struct crypto_async_request
*req
, int err
)
170 struct crypto_gcm_setkey_result
*result
= req
->data
;
172 if (err
== -EINPROGRESS
)
176 complete(&result
->completion
);
179 static int crypto_gcm_setkey(struct crypto_aead
*aead
, const u8
*key
,
182 struct crypto_gcm_ctx
*ctx
= crypto_aead_ctx(aead
);
183 struct crypto_ablkcipher
*ctr
= ctx
->ctr
;
188 struct crypto_gcm_setkey_result result
;
190 struct scatterlist sg
[1];
191 struct ablkcipher_request req
;
195 crypto_ablkcipher_clear_flags(ctr
, CRYPTO_TFM_REQ_MASK
);
196 crypto_ablkcipher_set_flags(ctr
, crypto_aead_get_flags(aead
) &
197 CRYPTO_TFM_REQ_MASK
);
199 err
= crypto_ablkcipher_setkey(ctr
, key
, keylen
);
203 crypto_aead_set_flags(aead
, crypto_ablkcipher_get_flags(ctr
) &
204 CRYPTO_TFM_RES_MASK
);
206 data
= kzalloc(sizeof(*data
) + crypto_ablkcipher_reqsize(ctr
),
211 init_completion(&data
->result
.completion
);
212 sg_init_one(data
->sg
, &data
->hash
, sizeof(data
->hash
));
213 ablkcipher_request_set_tfm(&data
->req
, ctr
);
214 ablkcipher_request_set_callback(&data
->req
, CRYPTO_TFM_REQ_MAY_SLEEP
|
215 CRYPTO_TFM_REQ_MAY_BACKLOG
,
216 crypto_gcm_setkey_done
,
218 ablkcipher_request_set_crypt(&data
->req
, data
->sg
, data
->sg
,
219 sizeof(data
->hash
), data
->iv
);
221 err
= crypto_ablkcipher_encrypt(&data
->req
);
222 if (err
== -EINPROGRESS
|| err
== -EBUSY
) {
223 err
= wait_for_completion_interruptible(
224 &data
->result
.completion
);
226 err
= data
->result
.err
;
232 if (ctx
->gf128
!= NULL
)
233 gf128mul_free_4k(ctx
->gf128
);
235 ctx
->gf128
= gf128mul_init_4k_lle(&data
->hash
);
237 if (ctx
->gf128
== NULL
)
245 static void crypto_gcm_init_crypt(struct ablkcipher_request
*ablk_req
,
246 struct aead_request
*req
,
247 unsigned int cryptlen
)
249 struct crypto_aead
*aead
= crypto_aead_reqtfm(req
);
250 struct crypto_gcm_ctx
*ctx
= crypto_aead_ctx(aead
);
251 struct crypto_gcm_req_priv_ctx
*pctx
= crypto_gcm_reqctx(req
);
252 u32 flags
= req
->base
.tfm
->crt_flags
;
253 struct crypto_gcm_ghash_ctx
*ghash
= &pctx
->ghash
;
254 struct scatterlist
*dst
;
255 __be32 counter
= cpu_to_be32(1);
257 memset(pctx
->auth_tag
, 0, sizeof(pctx
->auth_tag
));
258 memcpy(req
->iv
+ 12, &counter
, 4);
260 sg_init_table(pctx
->src
, 2);
261 sg_set_buf(pctx
->src
, pctx
->auth_tag
, sizeof(pctx
->auth_tag
));
262 scatterwalk_sg_chain(pctx
->src
, 2, req
->src
);
265 if (req
->src
!= req
->dst
) {
266 sg_init_table(pctx
->dst
, 2);
267 sg_set_buf(pctx
->dst
, pctx
->auth_tag
, sizeof(pctx
->auth_tag
));
268 scatterwalk_sg_chain(pctx
->dst
, 2, req
->dst
);
272 ablkcipher_request_set_tfm(ablk_req
, ctx
->ctr
);
273 ablkcipher_request_set_crypt(ablk_req
, pctx
->src
, dst
,
274 cryptlen
+ sizeof(pctx
->auth_tag
),
277 crypto_gcm_ghash_init(ghash
, flags
, ctx
->gf128
);
279 crypto_gcm_ghash_update_sg(ghash
, req
->assoc
, req
->assoclen
);
280 crypto_gcm_ghash_flush(ghash
);
283 static int crypto_gcm_hash(struct aead_request
*req
)
285 struct crypto_aead
*aead
= crypto_aead_reqtfm(req
);
286 struct crypto_gcm_req_priv_ctx
*pctx
= crypto_gcm_reqctx(req
);
287 u8
*auth_tag
= pctx
->auth_tag
;
288 struct crypto_gcm_ghash_ctx
*ghash
= &pctx
->ghash
;
290 crypto_gcm_ghash_update_sg(ghash
, req
->dst
, req
->cryptlen
);
291 crypto_gcm_ghash_final_xor(ghash
, req
->assoclen
, req
->cryptlen
,
294 scatterwalk_map_and_copy(auth_tag
, req
->dst
, req
->cryptlen
,
295 crypto_aead_authsize(aead
), 1);
299 static void crypto_gcm_encrypt_done(struct crypto_async_request
*areq
, int err
)
301 struct aead_request
*req
= areq
->data
;
304 err
= crypto_gcm_hash(req
);
306 aead_request_complete(req
, err
);
309 static int crypto_gcm_encrypt(struct aead_request
*req
)
311 struct crypto_gcm_req_priv_ctx
*pctx
= crypto_gcm_reqctx(req
);
312 struct ablkcipher_request
*abreq
= &pctx
->abreq
;
315 crypto_gcm_init_crypt(abreq
, req
, req
->cryptlen
);
316 ablkcipher_request_set_callback(abreq
, aead_request_flags(req
),
317 crypto_gcm_encrypt_done
, req
);
319 err
= crypto_ablkcipher_encrypt(abreq
);
323 return crypto_gcm_hash(req
);
326 static int crypto_gcm_verify(struct aead_request
*req
)
328 struct crypto_aead
*aead
= crypto_aead_reqtfm(req
);
329 struct crypto_gcm_req_priv_ctx
*pctx
= crypto_gcm_reqctx(req
);
330 struct crypto_gcm_ghash_ctx
*ghash
= &pctx
->ghash
;
331 u8
*auth_tag
= pctx
->auth_tag
;
332 u8
*iauth_tag
= pctx
->iauth_tag
;
333 unsigned int authsize
= crypto_aead_authsize(aead
);
334 unsigned int cryptlen
= req
->cryptlen
- authsize
;
336 crypto_gcm_ghash_final_xor(ghash
, req
->assoclen
, cryptlen
, auth_tag
);
338 authsize
= crypto_aead_authsize(aead
);
339 scatterwalk_map_and_copy(iauth_tag
, req
->src
, cryptlen
, authsize
, 0);
340 return memcmp(iauth_tag
, auth_tag
, authsize
) ? -EBADMSG
: 0;
343 static void crypto_gcm_decrypt_done(struct crypto_async_request
*areq
, int err
)
345 struct aead_request
*req
= areq
->data
;
348 err
= crypto_gcm_verify(req
);
350 aead_request_complete(req
, err
);
353 static int crypto_gcm_decrypt(struct aead_request
*req
)
355 struct crypto_aead
*aead
= crypto_aead_reqtfm(req
);
356 struct crypto_gcm_req_priv_ctx
*pctx
= crypto_gcm_reqctx(req
);
357 struct ablkcipher_request
*abreq
= &pctx
->abreq
;
358 struct crypto_gcm_ghash_ctx
*ghash
= &pctx
->ghash
;
359 unsigned int cryptlen
= req
->cryptlen
;
360 unsigned int authsize
= crypto_aead_authsize(aead
);
363 if (cryptlen
< authsize
)
365 cryptlen
-= authsize
;
367 crypto_gcm_init_crypt(abreq
, req
, cryptlen
);
368 ablkcipher_request_set_callback(abreq
, aead_request_flags(req
),
369 crypto_gcm_decrypt_done
, req
);
371 crypto_gcm_ghash_update_sg(ghash
, req
->src
, cryptlen
);
373 err
= crypto_ablkcipher_decrypt(abreq
);
377 return crypto_gcm_verify(req
);
380 static int crypto_gcm_init_tfm(struct crypto_tfm
*tfm
)
382 struct crypto_instance
*inst
= (void *)tfm
->__crt_alg
;
383 struct gcm_instance_ctx
*ictx
= crypto_instance_ctx(inst
);
384 struct crypto_gcm_ctx
*ctx
= crypto_tfm_ctx(tfm
);
385 struct crypto_ablkcipher
*ctr
;
389 ctr
= crypto_spawn_ablkcipher(&ictx
->ctr
);
397 align
= crypto_tfm_alg_alignmask(tfm
);
398 align
&= ~(crypto_tfm_ctx_alignment() - 1);
399 tfm
->crt_aead
.reqsize
= align
+
400 sizeof(struct crypto_gcm_req_priv_ctx
) +
401 crypto_ablkcipher_reqsize(ctr
);
406 static void crypto_gcm_exit_tfm(struct crypto_tfm
*tfm
)
408 struct crypto_gcm_ctx
*ctx
= crypto_tfm_ctx(tfm
);
410 if (ctx
->gf128
!= NULL
)
411 gf128mul_free_4k(ctx
->gf128
);
413 crypto_free_ablkcipher(ctx
->ctr
);
416 static struct crypto_instance
*crypto_gcm_alloc(struct rtattr
**tb
)
418 struct crypto_instance
*inst
;
419 struct crypto_alg
*ctr
;
420 struct crypto_alg
*cipher
;
421 struct gcm_instance_ctx
*ctx
;
423 char ctr_name
[CRYPTO_MAX_ALG_NAME
];
425 err
= crypto_check_attr_type(tb
, CRYPTO_ALG_TYPE_AEAD
);
429 cipher
= crypto_attr_alg(tb
[1], CRYPTO_ALG_TYPE_CIPHER
,
430 CRYPTO_ALG_TYPE_MASK
);
432 inst
= ERR_PTR(PTR_ERR(cipher
));
436 inst
= ERR_PTR(ENAMETOOLONG
);
437 if (snprintf(ctr_name
, CRYPTO_MAX_ALG_NAME
, "ctr(%s)",
438 cipher
->cra_name
) >= CRYPTO_MAX_ALG_NAME
)
441 ctr
= crypto_alg_mod_lookup(ctr_name
, CRYPTO_ALG_TYPE_BLKCIPHER
,
442 CRYPTO_ALG_TYPE_MASK
);
445 return ERR_PTR(PTR_ERR(ctr
));
447 if (cipher
->cra_blocksize
!= 16)
450 inst
= kzalloc(sizeof(*inst
) + sizeof(*ctx
), GFP_KERNEL
);
456 if (snprintf(inst
->alg
.cra_name
, CRYPTO_MAX_ALG_NAME
,
457 "gcm(%s)", cipher
->cra_name
) >= CRYPTO_MAX_ALG_NAME
||
458 snprintf(inst
->alg
.cra_driver_name
, CRYPTO_MAX_ALG_NAME
,
459 "gcm(%s)", cipher
->cra_driver_name
) >= CRYPTO_MAX_ALG_NAME
)
463 ctx
= crypto_instance_ctx(inst
);
464 err
= crypto_init_spawn(&ctx
->ctr
, ctr
, inst
, CRYPTO_ALG_TYPE_MASK
);
468 inst
->alg
.cra_flags
= CRYPTO_ALG_TYPE_AEAD
| CRYPTO_ALG_ASYNC
;
469 inst
->alg
.cra_priority
= ctr
->cra_priority
;
470 inst
->alg
.cra_blocksize
= 16;
471 inst
->alg
.cra_alignmask
= ctr
->cra_alignmask
| (__alignof__(u64
) - 1);
472 inst
->alg
.cra_type
= &crypto_aead_type
;
473 inst
->alg
.cra_aead
.ivsize
= 16;
474 inst
->alg
.cra_aead
.maxauthsize
= 16;
475 inst
->alg
.cra_ctxsize
= sizeof(struct crypto_gcm_ctx
);
476 inst
->alg
.cra_init
= crypto_gcm_init_tfm
;
477 inst
->alg
.cra_exit
= crypto_gcm_exit_tfm
;
478 inst
->alg
.cra_aead
.setkey
= crypto_gcm_setkey
;
479 inst
->alg
.cra_aead
.encrypt
= crypto_gcm_encrypt
;
480 inst
->alg
.cra_aead
.decrypt
= crypto_gcm_decrypt
;
492 static void crypto_gcm_free(struct crypto_instance
*inst
)
494 struct gcm_instance_ctx
*ctx
= crypto_instance_ctx(inst
);
496 crypto_drop_spawn(&ctx
->ctr
);
500 static struct crypto_template crypto_gcm_tmpl
= {
502 .alloc
= crypto_gcm_alloc
,
503 .free
= crypto_gcm_free
,
504 .module
= THIS_MODULE
,
507 static int __init
crypto_gcm_module_init(void)
509 return crypto_register_template(&crypto_gcm_tmpl
);
512 static void __exit
crypto_gcm_module_exit(void)
514 crypto_unregister_template(&crypto_gcm_tmpl
);
517 module_init(crypto_gcm_module_init
);
518 module_exit(crypto_gcm_module_exit
);
520 MODULE_LICENSE("GPL");
521 MODULE_DESCRIPTION("Galois/Counter Mode");
522 MODULE_AUTHOR("Mikko Herranen <mh1@iki.fi>");