linux-kernel - Re: [PATCH 4/4] coredump: documentation for proc and sysctl]

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Message-ID: <45BEF669.1060600@hitachi.com>
Date:	Tue, 30 Jan 2007 16:40:25 +0900
From:	"Kawai, Hidehiro" <hidehiro.kawai.ez@...achi.com>
To:	Pavel Machek <pavel@....cz>, Andrew Morton <akpm@...l.org>
Cc:	kernel list <linux-kernel@...r.kernel.org>,
	sugita <yumiko.sugita.yf@...achi.com>,
	Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
	Satoshi OSHIMA <soshima@...hat.com>,
	"Hideo AOKI@...hat" <haoki@...hat.com>
Subject: Re: [PATCH 4/4] coredump: documentation for proc and sysctl]

Hi Pavel and Andrew,

Pavel Machek wrote:
>>This patch adds the documentation for the following parameters:
>>  /proc/<pid>/core_flags
>>  /proc/sys/kernel/core_flags_enable
> 
> Sysctl seems really strange to me. Either the feature is safe to use,
> or it is not. Users can already ulimit -c 0, and we do not have
> "/proc/sys/kernel/allow_users_to_disable_their_core_dumps".

Oh, I had forgotten that.  Thank you for pointing out.  The purpose of
this sysctl is to prevent a bad process from hiding its memory.
But as you say, this sysctl isn't enough for the purpose.

Andrew wrote:
> Does this feature have any security implications?  For example, there might
> be system administration programs which force a coredump on a "bad"
> process, and leave the core somewhere for the administrator to look at. 

I have never heard of the story that ulimit -c 0 bothered an
administrator who wanted to force a coredump.  So even without this
sysctl, the administrator wouldn't bother about security concerns.
I'll drop it from the next version.

Thanks,
-- 
Hidehiro Kawai
Hitachi, Ltd., Systems Development Laboratory


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