linux-kernel - Re: Security fix for remapping of page 0 (was [PATCH] Change ZERO_SIZE

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: <4A26A689.1090300@redhat.com>
Date:	Wed, 03 Jun 2009 12:36:25 -0400
From:	Rik van Riel <riel@...hat.com>
To:	"Larry H." <research@...reption.com>
CC:	Christoph Lameter <cl@...ux-foundation.org>,
	Stephen Smalley <sds@...ho.nsa.gov>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	linux-mm@...ck.org, Alan Cox <alan@...rguk.ukuu.org.uk>,
	linux-kernel@...r.kernel.org, pageexec@...email.hu
Subject: Re: Security fix for remapping of page 0 (was [PATCH] Change	ZERO_SIZE_PTR
 to point at unmapped space)

Larry H. wrote:

> Christopher, crippling the system is truly not the way to fix this.
> There are many legitimate users of private|fixed mappings at 0. In
> addition, if you want to go ahead and break POSIX, at least make sure
> your patch closes the loophole.

I suspect there aren't many at all, and restricting them through
SELinux may be enough to mitigate the risk.

> If SELinux isn't present, that's not useful. If mmap_min_addr is
> enabled, that still won't solve what my original, utterly simple patch
> fixes.

Would anybody paranoid run their system without SELinux?

> The patch provides a no-impact, clean solution to prevent kmalloc(0)
> situations from becoming a security hazard. Nothing else.

True, the changes in your patch only affect a few code paths.

-- 
All rights reversed.
--
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/