linux-kernel - Re: [PATCH v4] x86/suspend: fix false positive KASAN warning on suspend/resume

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:   Fri, 2 Dec 2016 22:09:03 +0100
From:   Pavel Machek <pavel@....cz>
To:     Josh Poimboeuf <jpoimboe@...hat.com>
Cc:     Andrey Ryabinin <aryabinin@...tuozzo.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Len Brown <len.brown@...el.com>, linux-pm@...r.kernel.org,
        LKML <linux-kernel@...r.kernel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>,
        Andy Lutomirski <luto@...capital.net>,
        Scott Bauer <scott.bauer@...el.com>,
        "x86@...nel.org" <x86@...nel.org>,
        Alexander Potapenko <glider@...gle.com>,
        kasan-dev <kasan-dev@...glegroups.com>
Subject: Re: [PATCH v4] x86/suspend: fix false positive KASAN warning on
 suspend/resume

On Fri 2016-12-02 11:42:21, Josh Poimboeuf wrote:
> Resuming from a suspend operation is showing a KASAN false positive
> warning:
> 
> 
> Reported-by: Scott Bauer <scott.bauer@...el.com>
> Signed-off-by: Josh Poimboeuf <jpoimboe@...hat.com>

Acked-by: Pavel Machek <pavel@....cz>

> diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c
> index 0e9505f..b2a0cff 100644
> --- a/mm/kasan/kasan.c
> +++ b/mm/kasan/kasan.c
> @@ -80,7 +80,14 @@ void kasan_unpoison_task_stack(struct task_struct *task)
>  /* Unpoison the stack for the current task beyond a watermark sp value. */
>  asmlinkage void kasan_unpoison_task_stack_below(const void *watermark)
>  {
> -	__kasan_unpoison_stack(current, watermark);
> +	/*
> +	 * Calculate the task stack base address.  Avoid using 'current'
> +	 * because this function is called by early resume code which hasn't
> +	 * yet set up the percpu register (%gs).
> +	 */
> +	void *base = (void *)((unsigned long)watermark & ~(THREAD_SIZE - 1));
> +
> +	kasan_unpoison_shadow(base, watermark - base);
>  }
>  

I know you modified this code to be arch-independend... but is it
really? I guess it is portable enough across architectures that run
kasan today..
									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Download attachment "signature.asc" of type "application/pgp-signature" (182 bytes)