Bug 1796360 (CVE-2019-18282)

Summary:	CVE-2019-18282 kernel: The flow_dissector feature allows device tracking
Product:	[Other] Security Response	Reporter:	msiddiqu
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	acaringi, airlied, bhu, blc, brdeoliv, bskeggs, dhoward, dvlasenk, esammons, fhrbata, hdegoede, hkrzesin, iboverma, ichavero, itamar, jarodwilson, jeremy, jforbes, jglisse, jlelli, john.j5live, jonathan, josef, jross, jshortt, jstancek, jwboyer, kernel-maint, kernel-mgr, lgoncalv, linville, masami256, matt, mchehab, mcressma, mjg59, mlangsdo, mleitner, nmurray, qzhao, rt-maint, rvrbovsk, sgrubb, steved, williams, wmealing
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:	A device tracking vulnerability was found in the flow_dissector feature in the Linux kernel. This flaw occurs because the auto flowlabel of the UDP IPv6 packet relies on a 32-bit hashmd value as a secret, and jhash (instead of siphash) is used. The hashmd value remains the same starting from boot time and can be inferred by an attacker.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2020-12-15 22:18:17 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:	1789862, 1796364, 1796365, 1835614, 1835615, 1835616, 1835617, 1835618
Bug Blocks:	1805744

Description msiddiqu 2020-01-30 09:36:06 UTC

The flow_dissector feature in the Linux kernel has a device tracking vulnerability. This occurs because the auto flowlabel of a UDP IPv6 packet relies on a 32-bit hashmd value as a secret, and because jhash (instead of siphash) is used. The hashmd value remains the same starting from boot time, and can be inferred by an attacker. This affects net/core/flow_dissector.c and related code.

Upstream commit:

https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=55667441c84fa5e0911a0aac44fb059c15ba6da2

References: 

https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.3.10

Comment 1 msiddiqu 2020-01-30 09:39:53 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1796364]

Comment 2 Justin M. Forbes 2020-01-30 15:55:05 UTC

This was fixed for Fedora with the 5.3.10 stable kernel update.

Comment 11 Wade Mealing 2020-05-14 07:30:07 UTC

Identification of systems behind network routers in itself is not a security vulnerability, allowing identification of them when not intended could be considered one.

There is no trust boundary crossed in this flaw.  It is an 'information leak' about systems behind the system being used as a router.  By itself, it provides no real threat to a the system acting as a router.

Comment 19 Petr Matousek 2020-05-26 12:54:54 UTC

Mitigation:

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Comment 21 Wade Mealing 2020-05-27 05:47:07 UTC

Also, updated my config files, background updating tool wasnt working.

Comment 22 errata-xmlrpc 2020-12-15 11:11:49 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2020:5437 https://access.redhat.com/errata/RHSA-2020:5437

Comment 23 errata-xmlrpc 2020-12-15 11:16:42 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2020:5441 https://access.redhat.com/errata/RHSA-2020:5441

Comment 24 Product Security DevOps Team 2020-12-15 22:18:17 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-2019-18282