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: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Herbert Xu 2015-05-21 15:11:09 +08:00
parent 63293c6113
commit 330234638e
2 changed files with 42 additions and 0 deletions

View File

@ -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;

View File

@ -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