linux-kernel - Re: is avoiding compat ioctls possible?

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: <20091028035121.GH7744@basil.fritz.box>
Date:	Wed, 28 Oct 2009 04:51:21 +0100
From:	Andi Kleen <andi@...stfloor.org>
To:	David Miller <davem@...emloft.net>
Cc:	airlied@...ux.ie, airlied@...il.com, andi@...stfloor.org,
	arnd@...db.de, linux-kernel@...r.kernel.org,
	dri-devel@...ts.sourceforge.net
Subject: Re: is avoiding compat ioctls possible?

On Tue, Oct 27, 2009 at 08:45:30PM -0700, David Miller wrote:
> From: Dave Airlie <airlied@...ux.ie>
> Date: Wed, 28 Oct 2009 03:43:07 +0000 (GMT)
> 
> > we already opencoded this (probably before it was macroisied or we just 
> > pasted it), so the radeon one is buggy, I should just go and compat_* all 
> > of these then and we should be all happy?
> 
> It should be, it's only working because:
> 
> 1) A malicious userland hasn't put garbage in the upper bits for
>    you yet.

The x86 compat_ptr wouldn't even help with that because it doesn't mask.

If they use *_user() or anything else with access_ok later that should
be caught properly. The user land could only put in pointers to unmapped 
[32bit...kernel boundary] data, which is harmless.

-Andi

-- 
ak@...ux.intel.com -- Speaking for myself only.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/