From: Rusty Russell <rusty@rustcorp•com.au>
To: Andi Kleen <andi@firstfloor•org>
Cc: Siarhei Liakh <sliakh.lkml@gmail•com>,
linux-kernel@vger•kernel.org,
linux-security-module@vger•kernel.org,
linux-next@vger•kernel.org,
Arjan van de Ven <arjan@infradead•org>,
James Morris <jmorris@namei•org>,
Andrew Morton <akpm@linux-foundation•org>, Andi Kleen <ak@muc•de>,
Thomas Gleixner <tglx@linutronix•de>,
"H. Peter Anvin" <hpa@zytor•com>, Ingo Molnar <mingo@elte•hu>,
Stephen Rothwell <sfr@canb•auug.org.au>,
Dave Jones <davej@redhat•com>
Subject: Re: [PATCH v8] RO/NX protection for loadable kernel modules
Date: Mon, 8 Feb 2010 12:15:31 +1030 [thread overview]
Message-ID: <201002081215.31527.rusty@rustcorp.com.au> (raw)
In-Reply-To: <873a1jdyrg.fsf@basil.nowhere.org>
On Wed, 3 Feb 2010 09:35:39 am Andi Kleen wrote:
> Siarhei Liakh <sliakh.lkml@gmail•com> writes:
>
> > This patch is a logical extension of the protection provided by
> > CONFIG_DEBUG_RODATA to LKMs. The protection is provided by splitting
> > module_core and module_init into three logical parts each and setting
> > appropriate page access permissions for each individual section:
>
> My current kernel has 52 modules loaded, most of them very small.
> Assuming the additional alignment of the data section cost two more
> pages on average (I think that's a good assumption), that's roughly
> 424KB of additional memory, plus associated runtime costs in increased
> TLB usage.
>
> What would I get for that if I applied the patch and enabled the option?
Strict RO/NX protection. But without the option enabled, the patch gives
best-effort protection, which is nice (for no additional space).
Cheers,
Rusty.
next prev parent reply other threads:[~2010-02-08 1:45 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-31 23:22 [PATCH v8] RO/NX protection for loadable kernel modules Siarhei Liakh
2010-02-01 1:39 ` Rusty Russell
2010-02-01 16:22 ` Siarhei Liakh
2010-02-02 23:05 ` Andi Kleen
2010-02-03 4:07 ` Siarhei Liakh
2010-02-08 1:45 ` Rusty Russell [this message]
2010-02-08 1:54 ` H. Peter Anvin
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