linux-kernel - Re: [PATCH v2] all arches, signal: Move restart_block to struct task

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:	Wed, 29 Oct 2014 19:12:57 +0100 (CET)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Andy Lutomirski <luto@...capital.net>
cc:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-arch <linux-arch@...r.kernel.org>,
	Al Viro <viro@...iv.linux.org.uk>,
	Richard Weinberger <richard.weinberger@...il.com>,
	"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...nel.org>,
	Kees Cook <keescook@...omium.org>
Subject: Re: [PATCH v2] all arches, signal: Move restart_block to struct
 task_struct

On Wed, 29 Oct 2014, Andy Lutomirski wrote:

> If an attacker can cause a controlled kernel stack overflow,
> overwriting the restart block is a very juicy exploit target.
> Moving the restart block to struct task_struct prevents this
> exploit.
> 
> Note that there are other fields in thread_info that are also easy
> targets, at least on some architectures.
> 
> It's also a decent simplification, since the restart code is more or
> less identical on all architectures.

I think that's the most important change. Moving common stuff into
common code. The side effect of slightly reducing the attack surface
is nice, but as Al pointed out not really the big win here.
 
Thanks,

	tglx
--
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/