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Commit 33023463 authored by Herbert Xu's avatar Herbert Xu
Browse files

crypto: null - Add default null skcipher 



This patch adds a default null skcipher for users such as gcm
to perform copies on SG lists.

Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 63293c61

crypto/crypto_null.c

+39 −0
Original line number Diff line number Diff line
@@ -25,6 +25,10 @@ 
#include <linux/mm.h>

#include <linux/string.h>



static DEFINE_MUTEX(crypto_default_null_skcipher_lock);

static struct crypto_blkcipher *crypto_default_null_skcipher;

static int crypto_default_null_skcipher_refcnt;



static int null_compress(struct crypto_tfm *tfm, const u8 *src,

			 unsigned int slen, u8 *dst, unsigned int *dlen)

{
@@ -149,6 +153,41 @@ MODULE_ALIAS_CRYPTO("compress_null"); 
MODULE_ALIAS_CRYPTO("digest_null");

MODULE_ALIAS_CRYPTO("cipher_null");



struct crypto_blkcipher *crypto_get_default_null_skcipher(void)

{

	struct crypto_blkcipher *tfm;



	mutex_lock(&crypto_default_null_skcipher_lock);

	tfm = crypto_default_null_skcipher;



	if (!tfm) {

		tfm = crypto_alloc_blkcipher("ecb(cipher_null)", 0, 0);

		if (IS_ERR(tfm))

			goto unlock;



		crypto_default_null_skcipher = tfm;

	}



	crypto_default_null_skcipher_refcnt++;



unlock:

	mutex_unlock(&crypto_default_null_skcipher_lock);



	return tfm;

}

EXPORT_SYMBOL_GPL(crypto_get_default_null_skcipher);



void crypto_put_default_null_skcipher(void)

{

	mutex_lock(&crypto_default_null_skcipher_lock);

	if (!--crypto_default_null_skcipher_refcnt) {

		crypto_free_blkcipher(crypto_default_null_skcipher);

		crypto_default_null_skcipher = NULL;

	}

	mutex_unlock(&crypto_default_null_skcipher_lock);

}

EXPORT_SYMBOL_GPL(crypto_put_default_null_skcipher);



static int __init crypto_null_mod_init(void)

{

	int ret = 0;

include/crypto/null.h

+3 −0
Original line number Diff line number Diff line
@@ -8,4 +8,7 @@ 
#define NULL_DIGEST_SIZE	0

#define NULL_IV_SIZE		0



struct crypto_blkcipher *crypto_get_default_null_skcipher(void);

void crypto_put_default_null_skcipher(void);



#endif