linux-kernel - Re: [PATCH] cgroup: fix potential null pointer risk

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 17 May 2022 07:07:37 -1000
From:   Tejun Heo <tj@...nel.org>
To:     Shida Zhang <starzhangzsd@...il.com>
Cc:     lizefan.x@...edance.com, hannes@...xchg.org, zhangshida@...inos.cn,
        linux-kernel@...r.kernel.org, cgroups@...r.kernel.org
Subject: Re: [PATCH] cgroup: fix potential null pointer risk

On Tue, May 17, 2022 at 03:31:06PM +0800, Shida Zhang wrote:
> We previously assumed 'parent' could be null,
> so null pointer judgment should be added.
> 
> Signed-off-by: Shida Zhang <zhangshida@...inos.cn>
> ---
>  kernel/cgroup/cgroup.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
> index adb820e98f24..7f230b0ab644 100644
> --- a/kernel/cgroup/cgroup.c
> +++ b/kernel/cgroup/cgroup.c
> @@ -5701,7 +5701,8 @@ static int cgroup_destroy_locked(struct cgroup *cgrp)
>  	}
>  	spin_unlock_irq(&css_set_lock);
>  
> -	cgroup1_check_for_release(parent);
> +	if (parent)
> +		cgroup1_check_for_release(parent);

The function is never called for a root cgroup. The parent check up above in
the same function is superflous. So, maybe remove that?

Thanks.

-- 
tejun