Re: CVE-2013-4287 Algorithmic complexity vulnerability in RubyGems 2.0.7 and older

[Kurt Seifried <kseifried () redhat com>]

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On 09/14/2013 03:11 PM, Alexander Cherepanov wrote:
> On 2013-09-10 09:32, Eric Hodel wrote:
> > The vulnerability can be fixed by changing the first grouping to
> > an atomic grouping in Gem::Version::VERSION_PATTERN in
> > lib/rubygems/version.rb.  For RubyGems 2.0.x:
> >
> > -  VERSION_PATTERN =
> > '[0-9]+(\.[0-9a-zA-Z]+)*(-[0-9A-Za-z-]+(\.[0-9A-Za-z-]+)*)?' #
> > :nodoc: +  VERSION_PATTERN =
> > '[0-9]+(?>\.[0-9a-zA-Z]+)*(-[0-9A-Za-z-]+(\.[0-9A-Za-z-]+)*)?' #
> > :nodoc:
> >
> > For RubyGems 1.8.x:
> >
> > -  VERSION_PATTERN = '[0-9]+(\.[0-9a-zA-Z]+)*' # :nodoc: +
> > VERSION_PATTERN = '[0-9]+(?>\.[0-9a-zA-Z]+)*' # :nodoc:
>
> This is not enough. The following script:
>
> # Regexes are from 
> https://github.com/rubygems/rubygems/blob/master/lib/rubygems/version.rb#L150
VERSION_PATTERN =
> '[0-9]+(?>\.[0-9a-zA-Z]+)*(-[0-9A-Za-z-]+(\.[0-9A-Za-z-]+)*)?' #
> :nodoc: ANCHORED_VERSION_PATTERN =
> /\A\s*(#{VERSION_PATTERN})*\s*\z/ # :nodoc: 
> '1111111111111111111111111111.' =~ ANCHORED_VERSION_PATTERN
>
> takes ~1m on my machine. The problem is not in VERSION_PATTERN but
> in its possible repetition inside ANCHORED_VERSION_PATTERN.

Great, I guess we're going to need a new CVE. Before I assign one can
we make sure we fix this so more fiddly expressions don't cause
problems? Thanks.

- -- 
Kurt Seifried Red Hat Security Response Team (SRT)
PGP: 0x5E267993 A90B F995 7350 148F 66BF 7554 160D 4553 5E26 7993
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