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Date: Fri, 13 Apr 2007 09:38:52 -0400
From: "Christopher S. Aker" <caker@theshore.net>
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To: Alan Cox <alan@lxorguk.ukuu.org.uk>
CC: Andi Kleen <andi@firstfloor.org>,
       "Bill Rugolsky Jr." <brugolsky@telemetry-investments.com>,
       linux-kernel@vger.kernel.org
Subject: Re: [Feature Request?] Inline compression of process core dumps
References: <461E55C6.1030905@theshore.net>	<20070412172845.58bfeff5@the-village.bc.nu>	<20070412164251.GC11736@ti88.telemetry-investments.com>	<p73ps697agf.fsf@bingen.suse.de>	<461EE95A.3090600@theshore.net> <20070413133915.55cbf012@the-village.bc.nu>
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Alan Cox wrote:
>> Looking at the code, it seems to me that format_corename() is appending 
>> .pid, regardless if !core_uses_pid and corename[0]=='|', in which case 
>> it creates an invalid path for call_usermodehelper_pipe().
>>
>> Bug in the code, or bug in my methods?
> 
> This looks somewhat better and might do the trick. Also fixes a very very
> obscure security corner case. If you change core pattern to start with
> the program name then the user can run a program called "|myevilhack" as
> it stands. The patch checks for "|" in the pattern not the output and
> doesn't nail a pid on to a piped name.

<snip>

Works great now.  Queue this sucker up!

	# cat /proc/sys/kernel/core_pattern
	|/home/caker/bin/dumper.pl
	# ./linux
	<blah blah>
	Segmentation fault (core dumped)
	# file /tmp/dumper.out
	/tmp/dumper.out: ELF 32-bit LSB core file Intel 80386, version 1 
(SYSV), SVR4-style

Thanks for everyone's help.

-Chris