ubifs: Fix a memleak after dumping authentication mount options

Fix a memory leak after dumping authentication mount options in error
handling branch.

Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Cc: <stable@vger.kernel.org>  # 4.20+
Fixes: d8a2277 ("ubifs: Enable authentication support")
Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>

Author: Zhihao Cheng

fs/ubifs/super.c

@@ -1141,6 +1141,18 @@ static int ubifs_parse_options(struct ubifs_info *c, char *options,
 	return 0;
 }
 
+/*
+ * ubifs_release_options - release mount parameters which have been dumped.
+ * @c: UBIFS file-system description object
+ */
+static void ubifs_release_options(struct ubifs_info *c)
+{
+	kfree(c->auth_key_name);
+	c->auth_key_name = NULL;
+	kfree(c->auth_hash_name);
+	c->auth_hash_name = NULL;
+}
+
 /**
  * destroy_journal - destroy journal data structures.
  * @c: UBIFS file-system description object
@@ -1650,8 +1662,7 @@ static void ubifs_umount(struct ubifs_info *c)
 	ubifs_lpt_free(c, 0);
 	ubifs_exit_authentication(c);
 
-	kfree(c->auth_key_name);
-	kfree(c->auth_hash_name);
+	ubifs_release_options(c);
 	kfree(c->cbuf);
 	kfree(c->rcvrd_mst_node);
 	kfree(c->mst_node);
@@ -2219,6 +2230,7 @@ static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
 out_unlock:
 	mutex_unlock(&c->umount_mutex);
 out_close:
+	ubifs_release_options(c);
 	ubi_close_volume(c->ubi);
 out:
 	return err;