linux-kernel - Re: [RFC BUG?] dereference PAGE

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: <4638BC3E.9080708@goop.org>
Date:	Wed, 02 May 2007 09:28:46 -0700
From:	Jeremy Fitzhardinge <jeremy@...p.org>
To:	Bill Irwin <bill.irwin@...cle.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Dan Kruchinin <dubalom@...il.com>,
	linux-kernel@...r.kernel.org,
	Jeremy Fitzhardinge <jeremy@...source.com>,
	Andi Kleen <ak@...e.de>, Ingo Molnar <mingo@...e.hu>,
	"Eric W. Biederman" <ebiederm@...ssion.com>
Subject: Re: [RFC BUG?] dereference PAGE_OFFSET address (rc7-mm2)

Bill Irwin wrote:
> Brain dump before crashing for the night:
>
> The patch refuses to clobber already-present pagetable entries of
> whatever origin. There are pagetables prior to this setup covering the
> address range just above PAGE_OFFSET. If this theory is correct, you
> should only be able to go a few MB above PAGE_OFFSET before encountering
> unreadable kernel memory. IIRC those pagetables are a statically
> allocated array in assembly; altering that array to set supervisor bits
> may resolve it, though it may also be freed as initmem.
>   

I think this should be fixed now.  Eric made all those writes
unconditional (to fix a problem with PSE superpages not being created). 
The patch is in Andi's queue.

    J
-
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/