Bug 192474 - Command halts the system
Command halts the system
Product: Fedora
Classification: Fedora
Component: bash (Show other bugs)
All Linux
medium Severity medium
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Assigned To: Tim Waugh
Ben Levenson
Depends On:
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Reported: 2006-05-19 17:21 EDT by Hugo Cisneiros
Modified: 2007-11-30 17:11 EST (History)
0 users

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Doc Type: Bug Fix
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Last Closed: 2006-05-19 17:54:19 EDT
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RHEL 7.3 requirements from Atomic Host:
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Description Hugo Cisneiros 2006-05-19 17:21:34 EDT
Description of problem:

I don't know if this is really a bug in bash, but it's worthy looking. When 
any user executes a certain command, the system halts and becomes inaccessible 
(even with ssh). This is really annoying and brings some concerns about system 

The command is:
(:(){ :|:;};:)

Version-Release number of selected component (if applicable):


How reproducible:

Steps to Reproduce:
1. Open a terminal as any user (root or not root)
2. Type the following command: (:(){ :|:;};:)
3. Press Enter and see your system hanging and Hard Disk working.
Comment 1 Tim Waugh 2006-05-19 17:54:19 EDT
You need to set user limits with 'ulimit' or PAM's limits.conf.
Comment 2 Hugo Cisneiros 2006-05-19 18:14:59 EDT
Thank you for the input, I was already thinking of this... BTW, isn't be good 
to set a reasonable limit in FC defaults? As any user can execute that, normal 
users can be tricked to execute this, hanging the system. I think that 
preventing this per default is a good thing :) Just a thought.

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