crypto: hmac - Add support for cloning

Allow hmac to be cloned.  The underlying hash can be used directly
with a reference count.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/crypto/hmac.c b/crypto/hmac.c
index 3610ff0..09a7872 100644 (file)
--- a/crypto/hmac.c
+++ b/crypto/hmac.c
@@ -160,6 +160,20 @@ static int hmac_init_tfm(struct crypto_shash *parent)
        return 0;
 }
 
+static int hmac_clone_tfm(struct crypto_shash *dst, struct crypto_shash *src)
+{
+       struct hmac_ctx *sctx = hmac_ctx(src);
+       struct hmac_ctx *dctx = hmac_ctx(dst);
+       struct crypto_shash *hash;
+
+       hash = crypto_clone_shash(sctx->hash);
+       if (IS_ERR(hash))
+               return PTR_ERR(hash);
+
+       dctx->hash = hash;
+       return 0;
+}
+
 static void hmac_exit_tfm(struct crypto_shash *parent)
 {
        struct hmac_ctx *ctx = hmac_ctx(parent);
@@ -227,6 +241,7 @@ static int hmac_create(struct crypto_template *tmpl, struct rtattr **tb)
        inst->alg.import = hmac_import;
        inst->alg.setkey = hmac_setkey;
        inst->alg.init_tfm = hmac_init_tfm;
+       inst->alg.clone_tfm = hmac_clone_tfm;
        inst->alg.exit_tfm = hmac_exit_tfm;
 
        inst->free = shash_free_singlespawn_instance;