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  PHC 
Open Source and information security mailing list archives
Hash Suite for Android: free password hash cracker in your pocket
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Mon, 4 Jul 2011 00:01:06 +0400
From:	Vasiliy Kulikov <>
To:	Linus Torvalds <>
Subject: Re: [PATCH] proc: fix a race in do_io_accounting()

On Sun, Jul 03, 2011 at 12:24 -0700, Linus Torvalds wrote:
> On Sun, Jul 3, 2011 at 3:39 AM, Vasiliy Kulikov <> wrote:
> >
> > The order of locking is similar to the one inside of
> > ptrace_attach(): first goes cred_guard_mutex, then lock_task_sighand().
> Hmm. mm_for_maps() uses mutex_lock_killable(), as does lock_trace.

Killable/interruptable here makes sense.

> And neither proc_pid_wchan() nor the fd following ones
> (proc_pid_follow_link etc) use anything at all.
> So I'm not sure. And do we really even care about the theoretical
> race? Even if we do hit the race window and happen to get it just as a
> process turns setuid, it would seem to be totally harmless (we're not
> going to see any of the sensitive IO anyway).

I consider this as a theoretical race too unless there is a crazy bug in
scheduler/timer.  But IMO it's better to just fully remove the risk
(even purely theoretical) given the lock is simple and it doesn't cost


Vasiliy Kulikov - bringing security into open computing environments
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

Powered by blists - more mailing lists