Bug 815314 – bash range expansion with large numbers causes DoS

Bug 815314 - bash range expansion with large numbers causes DoS

Summary:	bash range expansion with large numbers causes DoS

Status:	CLOSED NOTABUG

Aliases:	None

Product:	Fedora
Classification:	Fedora
Component:	bash (Show other bugs)
Sub Component:
Version:	16
Hardware:	x86_64 Linux

Priority	unspecified Severity unspecified
Target Milestone:	---
Target Release:	---
Assigned To:	Roman Rakus
QA Contact:	Fedora Extras Quality Assurance
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Reported:	2012-04-23 06:45 EDT by ojab
Modified:	2014-01-12 19:14 EST (History)
CC List:	3 users (show)

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Doc Type:	Bug Fix
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Last Closed:	2012-04-23 08:53:39 EDT
Type:	Bug
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Description ojab 2012-04-23 06:45:00 EDT

Description of problem:
I'm using bash for loops with large-number ranges like {99450..99459} and one time typo led me to {994450..99459}, which led me to unresponsive system till OOM-killer.

Version-Release number of selected component (if applicable):
Name        : bash
Arch        : x86_64
Version     : 4.2.24
Release     : 1.fc16


Steps to Reproduce:
1. for i in {1..9999999}; do echo ${i} ; done
  
Actual results:
bash that cannot be killed via Ctrl-C/`kill` (`kill -9` works) and eats a LOT of RAM.

Expected results:
Expansion works or throws error (`too large number` or something like)

Additional info:
Also reproducible on Centos-5.8 x86_64.

Comment 1 Roman Rakus 2012-04-23 08:53:39 EDT

This is expected behaviour. It was several times discussed upstream. You should use c-style for cycle in this case.

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