linux-kernel - Re: Windows side agrees that lowmem corruption is a problem too

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: <4C0EBCE1.2070609@zytor.com>
Date:	Tue, 08 Jun 2010 14:57:53 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Alan Cox <alan@...rguk.ukuu.org.uk>
CC:	Ondrej Zary <linux@...nbow-software.org>,
	Ingo Molnar <mingo@...e.hu>,
	Yuhong Bao <yuhongbao_386@...mail.com>,
	linux-kernel@...r.kernel.org, gregkh@...e.de
Subject: Re: Windows side agrees that lowmem corruption is a problem too

On 06/08/2010 02:56 PM, Alan Cox wrote:
>>> I agree that dis-using <1M by default is probably the sanest option.
>>
>> But please limit it to newer systems only (DMI present && year > 200?). There 
>> are many old machines running fine. Losing 1MB from 16MB is a bad thing.
> 
> Losing the low 1MB is bad thing anyway for things like firmware flashing
> and other weird crap that needs low pages (floppy controllers etc).
> 
> Losing 64K (but reporting corruption in it in a big scary way) is
> probably sensible for distributions, but its a config item so its policy
> so that wouldn't be a problem.
> 
> It has to be painful to the vendors so they get complaints, reports and
> support call costs. Otherwise they won't have the correct incentives to
> fix their mess.

We have already functionally lost 64K on all existing machines... I
think the current blacklist covers 90% or more of all systems in
existence, and we keep filling in the few holes that remain.

Adding the remaining half-megabyte of RAM really shouldn't be done
unconditionally, but as I said it could plausibly be reserved for
ZONE_DMA only.

	-hpa

--
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/