linux-kernel - Re: rwx mapping between ex

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Message-ID: <5609AE16.2070204@zytor.com>
Date:	Mon, 28 Sep 2015 14:16:06 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Ingo Molnar <mingo@...nel.org>, Kees Cook <keescook@...omium.org>
Cc:	Stephen Smalley <sds@...ho.nsa.gov>,
	"x86@...nel.org" <x86@...nel.org>,
	lkml <linux-kernel@...r.kernel.org>
Subject: Re: rwx mapping between ex_table and rodata

On 09/25/2015 12:22 AM, Ingo Molnar wrote:
>>
>> To me it looks like another alignment/padding issue like got fixed
>> before. The space between __ex_table and rodata is (seems?) unused, so
>> the default page table permissions end up being W+X. Can we fix the
>> default to be NX instead? It'll make these bugs stay gone.
> 
> Yeah. Wanna send a patch for that?
> 

At least in the high mapping space, the default should be no permissions
(not present), rather than just NX.

	-hpa


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