From owner-freebsd-security  Tue Sep 15 03:52:58 1998
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Date: Tue, 15 Sep 1998 11:52:36 +0100 (BST)
From: Jay Tribick <netadmin@fastnet.co.uk>
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To: security@FreeBSD.ORG
Subject: grep ohdear /dev/zero in a tight loop freezes FreeBSD && OpenBSD
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Background
----------
FreeBSD bofh.fast.net.uk 2.2.6-RELEASE FreeBSD 2.2.6-RELEASE #0
root@bofh.fast.net.uk:/usr/src/sys/compile/GENERIC  i386

login.conf (ulimit) restrictions:

lockd:\
        :priority=20:\
        :openfiles=32:\
        :openfiles-cur=32:\
        :memoryuse-cur=10M:\
        :maxproc-cur=32:\
        :cputime=1h:\
        :stacksize=2M:\
        :memorylocked=4M:\
        :memoryuse=10M:\
        :coredumpsize=0M:\
        :welcome=/etc/motd.lusers:

Problem 
------- 
Executing the following shell script effectively freezes a
BSD box (tested on FreeBSD 2.2.6 & latest OpenBSD) regardless of the above
process, cpu and memory restrictions within 15-30 seconds: 

#!/bin/bash
while() do
	grep ohdear /dev/zero &
done

Any ideas on how to fix this or secure against it?
Regards,

Jay Tribick <netadmin@fastnet.co.uk>
--
[| Network Admin | FastNet International | http://fast.net.uk/ |]
[| Finger netadmin@fastnet.co.uk for contact info & PGP PubKey |]
[|   +44 (0)1273 T: 677633 F: 621631 e: netadmin@fast.net.uk   |]



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