block/rnbd-clt: Fix possible memleak

[ Upstream commit 46067844efdb8275ade705923120fc5391543b53 ]

In error case, we do not free the memory for blk_symlink_name.

Do it by free the memory in error case, and set to NULL
afterwards.

Also fix the condition in rnbd_clt_remove_dev_symlink.

Fixes: 64e8a6ece1a5 ("block/rnbd-clt: Dynamically alloc buffer for pathname & blk_symlink_name")
Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Reviewed-by: Md Haris Iqbal <haris.iqbal@cloud.ionos.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/block/rnbd/rnbd-clt-sysfs.c b/drivers/block/rnbd/rnbd-clt-sysfs.c
index d854f05..d9dd138 100644 (file)
--- a/drivers/block/rnbd/rnbd-clt-sysfs.c
+++ b/drivers/block/rnbd/rnbd-clt-sysfs.c
@@ -433,7 +433,7 @@ void rnbd_clt_remove_dev_symlink(struct rnbd_clt_dev *dev)
         * i.e. rnbd_clt_unmap_dev_store() leading to a sysfs warning because
         * of sysfs link already was removed already.
         */
-       if (strlen(dev->blk_symlink_name) && try_module_get(THIS_MODULE)) {
+       if (dev->blk_symlink_name && try_module_get(THIS_MODULE)) {
                sysfs_remove_link(rnbd_devs_kobj, dev->blk_symlink_name);
                kfree(dev->blk_symlink_name);
                module_put(THIS_MODULE);
@@ -516,7 +516,8 @@ static int rnbd_clt_add_dev_symlink(struct rnbd_clt_dev *dev)
        return 0;
 
 out_err:
-       dev->blk_symlink_name[0] = '\0';
+       kfree(dev->blk_symlink_name);
+       dev->blk_symlink_name = NULL ;
        return ret;
 }