[PATCH 19/20] KEYS: encrypted: use crypto_shash_tfm_digest()

[Eric Biggers]

From: Eric Biggers <ebigg...@google.com>

Instead of manually allocating a 'struct shash_desc' on the stack and
calling crypto_shash_digest(), switch to using the new helper function
crypto_shash_tfm_digest() which does this for us.

Cc: keyri...@vger.kernel.org
Signed-off-by: Eric Biggers <ebigg...@google.com>
---
 security/keys/encrypted-keys/encrypted.c | 18 +++---------------
 1 file changed, 3 insertions(+), 15 deletions(-)

diff --git a/security/keys/encrypted-keys/encrypted.c 
b/security/keys/encrypted-keys/encrypted.c
index f6797ba44bf716..14cf81d1a30b14 100644
--- a/security/keys/encrypted-keys/encrypted.c
+++ b/security/keys/encrypted-keys/encrypted.c
@@ -323,19 +323,6 @@ static struct key *request_user_key(const char 
*master_desc, const u8 **master_k
        return ukey;
 }
 
-static int calc_hash(struct crypto_shash *tfm, u8 *digest,
-                    const u8 *buf, unsigned int buflen)
-{
-       SHASH_DESC_ON_STACK(desc, tfm);
-       int err;
-
-       desc->tfm = tfm;
-
-       err = crypto_shash_digest(desc, buf, buflen, digest);
-       shash_desc_zero(desc);
-       return err;
-}
-
 static int calc_hmac(u8 *digest, const u8 *key, unsigned int keylen,
                     const u8 *buf, unsigned int buflen)
 {
@@ -351,7 +338,7 @@ static int calc_hmac(u8 *digest, const u8 *key, unsigned 
int keylen,
 
        err = crypto_shash_setkey(tfm, key, keylen);
        if (!err)
-               err = calc_hash(tfm, digest, buf, buflen);
+               err = crypto_shash_tfm_digest(tfm, buf, buflen, digest);
        crypto_free_shash(tfm);
        return err;
 }
@@ -381,7 +368,8 @@ static int get_derived_key(u8 *derived_key, enum 
derived_key_type key_type,
 
        memcpy(derived_buf + strlen(derived_buf) + 1, master_key,
               master_keylen);
-       ret = calc_hash(hash_tfm, derived_key, derived_buf, derived_buf_len);
+       ret = crypto_shash_tfm_digest(hash_tfm, derived_buf, derived_buf_len,
+                                     derived_key);
        kzfree(derived_buf);
        return ret;
 }
-- 
2.26.2