linux-kernel - Re: brk randomization breaks columns

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Message-ID: <20080205220431.GC1630@elf.ucw.cz>
Date:	Tue, 5 Feb 2008 23:04:31 +0100
From:	Pavel Machek <pavel@....cz>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	Jiri Kosina <jkosina@...e.cz>,
	kernel list <linux-kernel@...r.kernel.org>,
	Abel Bernabeu <abel.bernabeu@...il.com>,
	Hugh Dickins <hugh@...itas.com>,
	Arjan van de Ven <arjan@...radead.org>
Subject: Re: brk randomization breaks columns

On Tue 2008-02-05 17:09:13, Ingo Molnar wrote:
> 
> * Pavel Machek <pavel@....cz> wrote:
> 
> > > From: Jiri Kosina <jkosina@...e.cz>
> > > 
> > > brk: check the lower bound properly
> > > 
> > > There is a check in sys_brk(), that tries to make sure that we do not 
> > > underflow the area that is dedicated to brk heap.
> > > 
> > > The check is however wrong, as it assumes that brk area starts immediately 
> > > after the end of the code (+bss), which is wrong for example in 
> > > environments with randomized brk start. The proper way is to check whether 
> > > the address is not below the start_brk address.
> > > 
> > > Signed-off-by: Jiri Kosina <jkosina@...e.cz>
> > 
> > ACK.
> 
> actually, does the patch above from Jiri solve the problem with your 11 
> year old binaries too? (Sorry if it has been mentioned elsewhere, i 
> could not decode it from this thread.)

No, it should just make the problem more obvious...

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