linux-kernel - Re: [PATCH] exec: fix the racy usage of fs_struct->in

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] [day] [month] [year] [list]

Message-ID: <AA35714D-AB8B-4CC5-B298-2F1E00C4B3ED@kernel.org>
Date: Tue, 25 Mar 2025 11:40:15 -0700
From: Kees Cook <kees@...nel.org>
To: Christian Brauner <brauner@...nel.org>, Mateusz Guzik <mjguzik@...il.com>
CC: Oleg Nesterov <oleg@...hat.com>,
 syzbot <syzbot+1c486d0b62032c82a968@...kaller.appspotmail.com>,
 viro@...iv.linux.org.uk, jack@...e.cz, linux-fsdevel@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-mm@...ck.org,
 syzkaller-bugs@...glegroups.com
Subject: Re: [PATCH] exec: fix the racy usage of fs_struct->in_exec



On March 25, 2025 7:46:15 AM PDT, Christian Brauner <brauner@...nel.org> wrote:
>On Tue, Mar 25, 2025 at 03:15:06PM +0100, Mateusz Guzik wrote:
>> On Tue, Mar 25, 2025 at 2:30 PM Christian Brauner <brauner@...nel.org> wrote:
>> >
>> > On Tue, Mar 25, 2025 at 02:21:36PM +0100, Oleg Nesterov wrote:
>> > > On 03/25, Mateusz Guzik wrote:
>> > > >
>> > > > On Tue, Mar 25, 2025 at 11:10 AM Oleg Nesterov <oleg@...hat.com> wrote:
>> > > > >
>> > > > > On 03/24, Mateusz Guzik wrote:
>> > > > > >
>> > > > > > On Mon, Mar 24, 2025 at 7:28 PM Oleg Nesterov <oleg@...hat.com> wrote:
>> > > > > > >
>> > > > > > > So to me it would be better to have the trivial fix for stable,
>> > > > > > > exactly because it is trivially backportable. Then cleanup/simplify
>> > > > > > > this logic on top of it.
>> > > > > >
>> > > > > > So I got myself a crap testcase with a CLONE_FS'ed task which can
>> > > > > > execve and sanity-checked that suid is indeed not honored as expected.
>> > > > >
>> > > > > So you mean my patch can't fix the problem?
>> > > >
>> > > > No, I think the patch works.
>> > > >
>> > > > I am saying the current scheme is avoidably hard to reason about.
>> > >
>> > > Ah, OK, thanks. Then I still think it makes more sense to do the
>> > > cleanups you propose on top of this fix.
>> >
>> > I agree. We should go with Oleg's fix that in the old scheme and use
>> > that. And then @Mateusz your cleanup should please go on top!
>> 
>> Ok, in that case I'm gonna ship when I'm gonna ship(tm), maybe later this week.
>
>Ok, I've taken the patch as I've got a first round of fixes to send
>already.

Thanks! 

Acked-by: Kees Cook <kees@...nel.org>


-- 
Kees Cook