linux-kernel - Re: [PATCH] zram: fix null dereference of handle

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]

Message-ID: <20170920055125.GB9428@bbox>
Date:   Wed, 20 Sep 2017 14:51:25 +0900
From:   Minchan Kim <minchan@...nel.org>
To:     Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        linux-kernel@...r.kernel.org, kernel-team <kernel-team@....com>,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>
Subject: Re: [PATCH] zram: fix null dereference of handle

On Tue, Sep 19, 2017 at 07:21:25PM +0900, Sergey Senozhatsky wrote:
> Minchan,
> 
> I just ran across it [because I had a bug to analize where this
> part was involved]. I'd really prefer the kernel to BUG_ON immediately
> instead of dying in agony.
> 
> can we, please, return BUG_ON() back?
> 
> there is no point in trying to save the kernel once it did that type
> of violation.

I agree. If it happens, it would corrupt other user's buffer which ends
up leaking some private data from others so there is pointless to keep
system alive to debug it.

Do you mind sending a formal patch?
Thanks!

> 
> ---
> 
> diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
> index 7c38e850a8fc..685049a9048d 100644
> --- a/mm/zsmalloc.c
> +++ b/mm/zsmalloc.c
> @@ -1349,7 +1349,7 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle,
>          * pools/users, we can't allow mapping in interrupt context
>          * because it can corrupt another users mappings.
>          */
> -       WARN_ON_ONCE(in_interrupt());
> +       BUG_ON(in_interrupt());
>  
>         /* From now on, migration cannot move the object */
>         pin_tag(handle);
>