ubifs: use crypto_shash_tfm_digest()

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: linux-mtd@lists.infradead.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

fs/ubifs/auth.c

@@ -31,15 +31,9 @@ int __ubifs_node_calc_hash(const struct ubifs_info *c, const void *node,
 			    u8 *hash)
 {
 	const struct ubifs_ch *ch = node;
-	SHASH_DESC_ON_STACK(shash, c->hash_tfm);
-	int err;
-
-	shash->tfm = c->hash_tfm;
 
-	err = crypto_shash_digest(shash, node, le32_to_cpu(ch->len), hash);
-	if (err < 0)
-		return err;
-	return 0;
+	return crypto_shash_tfm_digest(c->hash_tfm, node, le32_to_cpu(ch->len),
+				       hash);
 }
 
 /**
@@ -53,15 +47,7 @@ int __ubifs_node_calc_hash(const struct ubifs_info *c, const void *node,
 static int ubifs_hash_calc_hmac(const struct ubifs_info *c, const u8 *hash,
 				 u8 *hmac)
 {
-	SHASH_DESC_ON_STACK(shash, c->hmac_tfm);
-	int err;
-
-	shash->tfm = c->hmac_tfm;
-
-	err = crypto_shash_digest(shash, hash, c->hash_len, hmac);
-	if (err < 0)
-		return err;
-	return 0;
+	return crypto_shash_tfm_digest(c->hmac_tfm, hash, c->hash_len, hmac);
 }
 
 /**

fs/ubifs/master.c

@@ -68,12 +68,9 @@ static int mst_node_check_hash(const struct ubifs_info *c,
 	u8 calc[UBIFS_MAX_HASH_LEN];
 	const void *node = mst;
 
-	SHASH_DESC_ON_STACK(shash, c->hash_tfm);
-
-	shash->tfm = c->hash_tfm;
-
-	crypto_shash_digest(shash, node + sizeof(struct ubifs_ch),
-			    UBIFS_MST_NODE_SZ - sizeof(struct ubifs_ch), calc);
+	crypto_shash_tfm_digest(c->hash_tfm, node + sizeof(struct ubifs_ch),
+				UBIFS_MST_NODE_SZ - sizeof(struct ubifs_ch),
+				calc);
 
 	if (ubifs_check_hash(c, expected, calc))
 		return -EPERM;

fs/ubifs/replay.c

@@ -558,7 +558,7 @@ static int is_last_bud(struct ubifs_info *c, struct ubifs_bud *bud)
 	return data == 0xFFFFFFFF;
 }
 
-/* authenticate_sleb_hash and authenticate_sleb_hmac are split out for stack usage */
+/* authenticate_sleb_hash is split out for stack usage */
 static int authenticate_sleb_hash(struct ubifs_info *c, struct shash_desc *log_hash, u8 *hash)
 {
 	SHASH_DESC_ON_STACK(hash_desc, c->hash_tfm);
@@ -569,15 +569,6 @@ static int authenticate_sleb_hash(struct ubifs_info *c, struct shash_desc *log_h
 	return crypto_shash_final(hash_desc, hash);
 }
 
-static int authenticate_sleb_hmac(struct ubifs_info *c, u8 *hash, u8 *hmac)
-{
-	SHASH_DESC_ON_STACK(hmac_desc, c->hmac_tfm);
-
-	hmac_desc->tfm = c->hmac_tfm;
-
-	return crypto_shash_digest(hmac_desc, hash, c->hash_len, hmac);
-}
-
 /**
  * authenticate_sleb - authenticate one scan LEB
  * @c: UBIFS file-system description object
@@ -624,7 +615,8 @@ static int authenticate_sleb(struct ubifs_info *c, struct ubifs_scan_leb *sleb,
 			if (err)
 				goto out;
 
-			err = authenticate_sleb_hmac(c, hash, hmac);
+			err = crypto_shash_tfm_digest(c->hmac_tfm, hash,
+						      c->hash_len, hmac);
 			if (err)
 				goto out;