Bug 192474

Summary: Command halts the system
Product: [Fedora] Fedora Reporter: Hugo Cisneiros <hugo>
Component: bashAssignee: Tim Waugh <twaugh>
Status: CLOSED NOTABUG QA Contact: Ben Levenson <benl>
Severity: medium Docs Contact:
Priority: medium    
Version: 5   
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Hardware: All   
OS: Linux   
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Fixed In Version: Doc Type: Bug Fix
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Last Closed: 2006-05-19 21:54:19 UTC Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description Hugo Cisneiros 2006-05-19 21:21:34 UTC
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 
security.

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

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

bash-3.1-6.2

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 21:54:19 UTC
You need to set user limits with 'ulimit' or PAM's limits.conf.

Comment 2 Hugo Cisneiros 2006-05-19 22:14:59 UTC
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.