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Date: Thu, 18 Nov 2004 16:52:26 -0800 (PST)
From: Linus Torvalds <torvalds@osdl.org>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Potential security problem in patch: Fix reading /proc/<pid>/mem
 when parent dies.
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On Thu, 18 Nov 2004, Alan Cox wrote:
> 
> The original point of this was that if our parent changed then our new
> parent is not aware of our special status. As a result we can send
> random signals to init and since it does not see SIGCLD we can get
> zombies or worse when we exit.

How could we send random signals? That's what the "exit_signal" thing is 
for, and the code does

	if (p->exit_signal != -1)
		p->exit_signal = SIGCHLD;

for that.

Is there any other way to set exit_signal afterwards? If so, I think we 
should have a security check at _that_ point.

		Linus