Bug 1412678 (CVE-2016-2339)

Summary:	CVE-2016-2339 ruby: Fiddle::Function.new heap buffer overflow
Product:	[Other] Security Response	Reporter:	Andrej Nemec <anemec>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	cpelland, dajohnso, dclarizi, gblomqui, gmccullo, gtanzill, hhorak, hhudgeon, jfrey, jhardy, jorton, jprause, kseifried, mmorsi, mtasaka, obarenbo, roliveri, ruby-maint, sardella, simaishi, s, strzibny, vanmeeuwen+fedora, vondruch
Target Milestone:	---	Keywords:	Security
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Hardware:	All
OS:	Linux
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Last Closed:	2017-01-18 00:19:40 UTC	Type:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Bug Depends On:
Bug Blocks:	1412685

Description Andrej Nemec 2017-01-12 14:35:15 UTC

An exploitable heap overflow vulnerability exists in the Fiddle::Function.new “initialize” function functionality of Ruby. In Fiddle::Function.new “initialize” heap buffer “arg_types” allocation is made based on args array length. Specially constructed object passed as element of args array can increase this array size after mentioned allocation and cause heap overflow.

References:

http://www.talosintelligence.com/reports/TALOS-2016-0034/

Comment 1 Andrej Nemec 2017-01-12 14:55:04 UTC

Upstream patch:

https://github.com/ruby/ruby/commit/bcc2421b4938fc1d9f5f3fb6ef2320571b27af42

Comment 2 Doran Moppert 2017-01-18 00:07:42 UTC

This flaw requires executing untrusted ruby code, or passing an untrusted class to the Fiddle module.  Either of these would already represent a vulnerability by design, so the impact from this flaw is Moderate at best.

The Fiddle module is not present in Ruby prior to version 1.9, so earlier versions are not affected.

Comment 3 Doran Moppert 2017-01-18 00:20:21 UTC

Statement:

Red Hat Product Security has rated this issue as having Moderate security
impact. This issue is not currently planned to be addressed in future
updates. For additional information, refer to the Issue Severity
Classification: https://access.redhat.com/security/updates/classification/.