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From: John Reiser <jreiser@BitWagon.com>
To: mike@navi.cx
Cc: linux-kernel@vger.kernel.org
Subject: Re: Potential bug in fs/binfmt_elf.c?
Date: Fri, 05 Mar 2004 10:28:07 -0800	[thread overview]
Message-ID: <4048C6B7.7080202@BitWagon.com> (raw)
In-Reply-To: <1078508281.3065.33.camel@linux.littlegreen>

> When mapping a nobits PT_LOAD segment with a memsize > filesize, the
> kernel calls set_brk (which in turns calls do_brk) to map and clear the
> area, but this discards access permissons on the mapping leading to rwx
> protection. This causes a load failure on systems where the VM cannot
> reserve swap space for the segment, unless overcommit is active (on many
> systems it's not on by default).
[snip]

I believe that's not the only problem with binfmt_elf.  If the total address
space described by the PT_LOADs is not exactly one contiguous interval, then
2.6.3 binfmt_elf fills in the gaps with 'prw.' of zero-filled pages, instead
of the intended "holes" with no mapping at all between isolated PT_LOADs.
One example is  https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=115913

-- 


  reply	other threads:[~2004-03-05 18:29 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-03-05 17:38 Potential bug in fs/binfmt_elf.c? Mike Hearn
2004-03-05 18:28 ` John Reiser [this message]
2004-03-06 18:46 ` Ulrich Drepper
2004-03-06 21:10   ` Mike Hearn
2004-03-07  6:11     ` Ulrich Drepper
2004-03-07  9:58       ` Mike Hearn
2004-03-07 10:46         ` Ulrich Drepper
2004-03-07 11:53           ` Mike Hearn
2004-03-07 21:32             ` Ulrich Drepper
2004-03-07 23:55     ` Eric W. Biederman
2004-03-08  5:57       ` John Reiser
2004-03-08  8:06         ` Jakub Jelinek
2004-03-11  6:17           ` [PATCH] binfmt_elf.c allow .bss with no access (p---) John Reiser
2004-03-11 14:23             ` Mike Hearn
2004-03-11 19:18               ` John Reiser
2004-03-12 16:42                 ` Mike Hearn
     [not found]             ` <20040412185317.79ac7d7d.akpm@osdl.org>
2004-04-13 17:33               ` John Reiser

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