Bug 1332860 (CVE-2016-4537, CVE-2016-4538)

Summary:	CVE-2016-4537 CVE-2016-4538 php: bcpowmod accepts negative scale causing heap buffer overflow corrupting _one_ definition
Product:	[Other] Security Response	Reporter:	Adam Mariš <amaris>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	abhgupta, dmcphers, fedora, jialiu, jokerman, jorton, kseifried, lmeyer, mmaslano, mmccomas, rcollet, tiwillia, webstack-team, yozone
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	php 5.5.35, php 5.6.21, php 7.0.6	Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2016-06-13 10:36:34 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:	1332882
Bug Blocks:	1332879

Description Adam Mariš 2016-05-04 08:49:38 UTC

It was found that bcpowmod accepts negative scale causing heap buffer overflow, which corrupts _one_ definition.

Upstream bug:

https://bugs.php.net/bug.php?id=72093

Upstream patch:

https://git.php.net/?p=php-src.git;a=commit;h=ed52bcb3dcb2e7dbc009ef8c6579fb1276ca73c1

Comment 1 Adam Mariš 2016-05-04 09:25:41 UTC

Created php tracking bugs for this issue:

Affects: fedora-all [bug 1332882]

Comment 2 Andrej Nemec 2016-05-06 06:50:34 UTC

As per CVE assignment:

http://seclists.org/oss-sec/2016/q2/259

Use CVE-2016-4537 for "bcpowmod accepting negative scale."

Use CVE-2016-4538 for "_one_ definition being overridden by scale adjustment."

Comment 3 Fedora Update System 2016-05-07 11:47:45 UTC

php-5.6.21-1.fc24 has been pushed to the Fedora 24 stable repository. If problems still persist, please make note of it in this bug report.

Comment 4 Fedora Update System 2016-05-12 07:22:48 UTC

php-5.6.21-1.fc22 has been pushed to the Fedora 22 stable repository. If problems still persist, please make note of it in this bug report.

Comment 5 Tomas Hoger 2016-06-13 10:36:34 UTC

Issue is triggered by a negative $scale, which is not likely to come from an untrusted source, making this hard to trigger other way than by a malicious script.

This issue is in the bcmath extension.  In Red Hat products, this extension is packaged separately in php-bcmath sub-RPM.  Systems without that package installed can not be affected by this issue.

Comment 6 errata-xmlrpc 2016-11-15 11:51:39 UTC

This issue has been addressed in the following products:

  Red Hat Software Collections for Red Hat Enterprise Linux 6
  Red Hat Software Collections for Red Hat Enterprise Linux 6.7 EUS
  Red Hat Software Collections for Red Hat Enterprise Linux 7
  Red Hat Software Collections for Red Hat Enterprise Linux 7.2 EUS
  Red Hat Software Collections for Red Hat Enterprise Linux 7.3 EUS

Via RHSA-2016:2750 https://rhn.redhat.com/errata/RHSA-2016-2750.html