Re: [PATCH] ovl: Fix potential memory leak

From: Miklos Szeredi
Date: Mon Aug 22 2022 - 11:27:15 EST


On Mon, 22 Aug 2022 at 13:53, Stanislav Goriainov <goriainov@xxxxxxxxx> wrote:
>
> ovl: Fix potential memory leak in ovl_lookup()
>
> If memory for uperredirect was allocated with kstrdup()
> in upperdir != NULL and d.redirect != NULL path,
> it may be lost when upperredirect is reassigned later.

Can't happen because the first assignment of upperredirect will only
happen if upperdentry is non-NULL, while second one will only happen
if upperdentry is NULL. I understand why static checker fails to see
this: it doesn't know that dentry->d_name will never contain '/'. In
this case the looped call to ovl_lookup_single() can be ignored and it
is trivial to prove that d.redirect can only be set if *ret is
non-NULL.

Thanks,
Miklos