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  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:   Wed, 29 Sep 2021 20:00:42 +0100
From:   Mark Brown <>
To:     Kees Cook <>
Cc:     Josh Poimboeuf <>,
        Mark Rutland <>,
        Vito Caputo <>,
        Jann Horn <>,
        Thomas Gleixner <>,
        Ingo Molnar <>, Borislav Petkov <>,
        "H. Peter Anvin" <>, Jens Axboe <>,
        Peter Zijlstra <>,
        Stefan Metzmacher <>,
        Andy Lutomirski <>,
        Lai Jiangshan <>,
        Christian Brauner <>,
        Andrew Morton <>,
        "" <>,
        Daniel Bristot de Oliveira <>,
        Michael WeiƟ 
        Anand K Mistry <>,
        Alexey Gladkov <>,
        Michal Hocko <>, Helge Deller <>,
        Dave Hansen <>,
        Andrea Righi <>,
        Ohhoon Kwon <>,
        Kalesh Singh <>,
        YiFei Zhu <>,
        "Eric W. Biederman" <>,
        Qi Zheng <>,,,,
Subject: Re: [PATCH] proc: Disable /proc/$pid/wchan

On Wed, Sep 29, 2021 at 11:54:55AM -0700, Kees Cook wrote:
> On Mon, Sep 27, 2021 at 01:50:56PM -0700, Josh Poimboeuf wrote:

> > Even with that patch, it doesn't lock the task's runqueue before reading
> > the stack, so there's still the possibility of the task running on
> > another CPU and the unwinder going off the rails a bit, which might be
> > used by an attacker in creative ways similar to the /proc/<pid>/stack
> > vulnerability Jann mentioned earlier.

> Since I think we're considering get_wchan() to be slow-path, can we just
> lock the runqueue and use arch_stack_walk_reliable()?

Unfortunately arch_stack_walk_reliable() is only available for powerpc,
s390 and x86 currently - work is in progress to implement it for arm64
as well but it's not there yet.

Download attachment "signature.asc" of type "application/pgp-signature" (489 bytes)

Powered by blists - more mailing lists