linux-kernel - Re: [Linaro-mm-sig] [RFC] ARM DMA mapping TODO, v1

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: <1304116637.2513.252.camel@pasglop>
Date:	Sat, 30 Apr 2011 08:37:17 +1000
From:	Benjamin Herrenschmidt <benh@...nel.crashing.org>
To:	Arnd Bergmann <arnd@...db.de>
Cc:	Jesse Barnes <jbarnes@...tuousgeek.org>,
	KyongHo Cho <pullip.cho@...sung.com>,
	linaro-mm-sig@...ts.linaro.org,
	Thomas Hellstrom <thellstrom@...are.com>,
	Russell King - ARM Linux <linux@....linux.org.uk>,
	linux-kernel@...r.kernel.org,
	FUJITA Tomonori <fujita.tomonori@....ntt.co.jp>,
	Catalin Marinas <catalin.marinas@....com>,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [Linaro-mm-sig] [RFC] ARM DMA mapping TODO, v1

On Fri, 2011-04-29 at 20:29 +0200, Arnd Bergmann wrote:
> 
> If that is the case, we can probably work around this by turning the
> entire
> linear mapping (except for the kernel binary) into nonexecutable mode,
> if we don't do that already.
> This is desirable for security purposes anyway 

You'd still have an "edge" problem if you use large pages for the linear
mapping, you can't obviously make part of the kernel text NX and you'd
have to make sure you 'exclude' from those GPU allocations whatever
overlaps with your last executable large page.

In a way, it's a similar problem I have with bolted memory on BookE
where I can't restrict GPU allocations to memory that isn't bolted :-)

Cheers,
Ben.


--
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/