linux-kernel - Re: [PATCH v21 12/12] x86: Zero-pad the VVAR 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: <20140302104603.GA18257@gmail.com>
Date:	Sun, 2 Mar 2014 11:46:03 +0100
From:	Ingo Molnar <mingo@...nel.org>
To:	Stefani Seibold <stefani@...bold.net>
Cc:	gregkh@...uxfoundation.org, linux-kernel@...r.kernel.org,
	x86@...nel.org, tglx@...utronix.de, mingo@...hat.com,
	hpa@...or.com, ak@...ux.intel.com, aarcange@...hat.com,
	john.stultz@...aro.org, luto@...capital.net, xemul@...allels.com,
	gorcunov@...nvz.org, andriy.shevchenko@...ux.intel.com,
	Martin.Runge@...de-schwarz.com, Andreas.Brief@...de-schwarz.com
Subject: Re: [PATCH v21 12/12] x86: Zero-pad the VVAR page


* Stefani Seibold <stefani@...bold.net> wrote:

> By coincidence, the VVAR page is at the end of an ELF segment.  As a
> result, if it ends up being a partial page, the kernel loader will
> leave garbage behind at the end of the vvar page.  Zero-pad it to a
> full page to fix this issue.
> 
> This has probably been broken since the VVAR page was introduced.
> On QEMU, if you dump the run-time contents of the VVAR page, you can
> find entertaining strings from seabios left behind.
> 
> It's remotely possible that this is a security bug -- conceivably
> there's some BIOS out there that leaves something sensitive in the
> few K of memory that is exposed to userspace.
> 
> Signed-off-by: Andy Lutomirski <luto@...capital.net>
> Signed-off-by: Stefani Seibold <stefani@...bold.net>

That's not a valid signoff sequence - if the patch came from Andy then 
the patch needs to contain a From: Andy line as well. If Andy acked or 
reviewed the patch then please add an Acked-by or Reviewed-by line.

Thanks,

	Ingo
--
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/