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: <563B5F64.1010806@oracle.com>
Date:	Thu, 5 Nov 2015 08:53:40 -0500
From:	Boris Ostrovsky <boris.ostrovsky@...cle.com>
To:	Sander Eikelenboom <linux@...elenboom.it>,
	Stephen Smalley <sds@...ho.nsa.gov>
Cc:	linux-kernel@...r.kernel.org, x86@...nel.org,
	David Vrabel <david.vrabel@...rix.com>,
	xen-devel@...ts.xen.org, mingo.kernel.org@...il.com
Subject: Re: [Xen-devel] Linux 4.4 MW: Boot under Xen fails with
 CONFIG_DEBUG_WX enabled: RIP: ptdump_walk_pgd_level_core

On 11/05/2015 04:13 AM, Sander Eikelenboom wrote:
>
> It makes "cat /sys/kernel/debug/kernel_page_tables" work and
> prevents a kernel with CONFIG_DEBUG_WX=y from crashing at boot.

Great. Our nightly runs also failed spectacularly due to this bug.

>
> It now does give a warning about an insecure W+X mapping, so 
> CONFIG_DEBUG_WX=y
> seems to be working. No idea how to interpret it though (and if it's a 
> legit
> warning).
>
> -- 
> Sander
>
> [   19.034706] Freeing unused kernel memory: 1104K (ffffffff822fc000 - 
> ffffffff82410000)
> [   19.041339] Write protecting the kernel read-only data: 18432k
> [   19.052596] Freeing unused kernel memory: 1144K (ffff880001ae2000 - 
> ffff880001c00000)
> [   19.060285] Freeing unused kernel memory: 1560K (ffff88000207a000 - 
> ffff880002200000)
> [   19.067079] ------------[ cut here ]------------
> [   19.073931] WARNING: CPU: 5 PID: 1 at 
> arch/x86/mm/dump_pagetables.c:225 note_page+0x619/0x7e0()

Yes, this apparently is a known issue: https://lkml.org/lkml/2015/11/4/476

-boris


--
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/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ