Bug 1581274 (CVE-2018-11237)

Summary:	CVE-2018-11237 glibc: Buffer overflow in __mempcpy_avx512_no_vzeroupper
Product:	[Other] Security Response	Reporter:	Andrej Nemec <anemec>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	abhgupta, alanm, aoliva, arjun.is, ashankar, codonell, dbaker, dj, fweimer, glibc-bugzilla, jokerman, law, mfabian, mnewsome, pfrankli, rth, sardella, siddhesh, sthangav, trankin
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	glibc 2.28	Doc Type:	If docs needed, set a value
Doc Text:	A buffer overflow has been discovered in the GNU C Library (aka glibc or libc6) in the __mempcpy_avx512_no_vzeroupper function when particular conditions are met. An attacker could use this vulnerability to cause a denial of service or potentially execute code.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2019-06-10 10:26:12 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:	1579809, 1581275, 1581276, 1582349, 1582350, 1849767
Bug Blocks:	1581278

Description Andrej Nemec 2018-05-22 12:53:11 UTC

An AVX-512-optimized implementation of the mempcpy function in the GNU C Library (aka glibc or libc6) 2.27 and earlier may write data beyond the target buffer, leading to a buffer overflow in __mempcpy_avx512_no_vzeroupper.

Upstream issue:

https://sourceware.org/bugzilla/show_bug.cgi?id=23196

Product bug:

https://bugzilla.redhat.com/show_bug.cgi?id=1579809

Comment 1 Andrej Nemec 2018-05-22 12:54:30 UTC

Created glibc tracking bugs for this issue:

Affects: fedora-all [bug 1581275]

Comment 4 Riccardo Schirone 2018-05-24 08:16:23 UTC

Patch:
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=9aaaab7c6e4176e61c59b0a63c6ba906d875dc0e

Comment 5 Riccardo Schirone 2018-05-24 08:25:23 UTC

The vulnerable code can be reached only in particular configurations and in particular cases. First, mempcpy has to be resolved to __mempcpy_avx512_no_vzeroupper, thus the CPU needs to support AVX512 instructions. Moreover, the size to be copied has to be greater than a dynamic value internal to glibc and other conditions need to apply.

For these reasons, I'm setting Attack Complexity to High (AC:H).

Comment 9 errata-xmlrpc 2018-10-30 07:36:24 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2018:3092 https://access.redhat.com/errata/RHSA-2018:3092