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Subject: Re: [patch] remove MNT_NOEXEC check for PROT_EXEC mmaps
From: Arjan van de Ven <arjan@infradead.org>
To: Stas Sergeev <stsp@aknet.ru>
Cc: Ulrich Drepper <drepper@redhat.com>,
       Linux kernel <linux-kernel@vger.kernel.org>,
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Date: Tue, 03 Oct 2006 21:54:25 +0200
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On Tue, 2006-10-03 at 23:40 +0400, Stas Sergeev wrote:
> Hello.
> 
> Ulrich Drepper wrote:
> > You really don't get it, do you.
> Yes, sorry. :)
> 
> > The way ld.so works can be implemented
> > in many other forms with other programs.
> Having "noexec" (in its older form) on *every* user-writable
> mount makes it harder for an attacker to run his own loaders,
> so implementing it in other forms was useless in the past.
> 
> > With some time and energy you
> > likely can write a perl or python script to do it.
> This is solvable the same way too - "chmod 'o-x' perl"

and chmod o-x bash ....
at which point.. game over.
(and yes you can do in bash pretty much what you can do in perl. heck
you can prove that.. shell is turning complete ;)