Bug 1837650 (CVE-2018-21232)

Summary:	CVE-2018-21232 re2c: uncontrolled recursion that causes stack consumption in find_fixed_tags
Product:	[Other] Security Response	Reporter:	Guilherme de Almeida Suckevicz <gsuckevi>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	fedora, i, orion, rhughes, seancallaway
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	re2c 2.0	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2020-05-20 03:15:22 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	1837651

Description Guilherme de Almeida Suckevicz 2020-05-19 18:23:35 UTC

re2c before 2.0 has uncontrolled recursion that causes stack consumption in find_fixed_tags.

References:
https://github.com/skvadrik/re2c/issues/219
https://www.openwall.com/lists/oss-security/2020/04/27/2
http://www.openwall.com/lists/oss-security/2020/05/14/4

Comment 1 Todd Cullum 2020-05-20 02:36:05 UTC

It appears that re2c was either not tested or not designed for use with small-stack systems (~256kb) in mind. In more than 4 components[1], it uses recursion which creates a stack overflow on systems with such small stack sizes.

1. https://www.openwall.com/lists/oss-security/2020/04/27/2

Comment 2 Todd Cullum 2020-05-20 02:37:14 UTC

Statement:

This vulnerability does not affect any version of re2c shipped with any version of Red Hat Enterprise Linux.

Comment 3 Product Security DevOps Team 2020-05-20 03:15:22 UTC

This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):

https://access.redhat.com/security/cve/cve-2018-21232