Bug 1831699 (CVE-2020-12465)

Summary:	CVE-2020-12465 kernel: buffer overflow in mt76_add_fragment function in drivers/net/wireless/mediatek/mt76/dma.c
Product:	[Other] Security Response	Reporter:	Guilherme de Almeida Suckevicz <gsuckevi>
Component:	vulnerability	Assignee:	Nobody <nobody>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	acaringi, airlied, bhu, blc, bmasney, dvlasenk, hdegoede, hkrzesin, itamar, jarodwilson, jeremy, jforbes, jlelli, john.j5live, jonathan, josef, jross, jshortt, jstancek, jwboyer, kcarcia, kernel-maint, kernel-mgr, lgoncalv, linville, masami256, mchehab, mjg59, mlangsdo, nmurray, ptalbert, qzhao, rkeshri, rt-maint, rvrbovsk, steved, williams
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 memory overflow and data corruption flaw were found in the Mediatek MT76 driver module for WiFi in mt76_add_fragment in drivers/net/wireless/mediatek/mt76/dma.c. An oversized packet with too many rx fragments causes an overflow and corruption in memory of adjacent pages. A local attacker with a special user or root privileges can cause a denial of service or a leak of internal kernel information.	Story Points:	---
Clone Of:		Environment:
Last Closed:		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:	1807052, 1831703, 1836205
Bug Blocks:	1831702

Description Guilherme de Almeida Suckevicz 2020-05-05 14:01:26 UTC

There was a memory overflow and data corruption flaw seen in the Mediatek MT76 driver module for wifi in mt76_add_fragment in drivers/net/wireless/mediatek/mt76/dma.c.  In this problem an oversized packet with too many rx fragments causes an overflow and a corruption in memory of adjacent pages. A local attacker with special user (or root) privilege can cause a DoS or a leak of internal kernel information.

Reference:
https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.5.10

Upstream commit:
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=b102f0c522cf668c8382c56a4f771b37d011cda2

Comment 1 Guilherme de Almeida Suckevicz 2020-05-05 14:06:34 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1831703]

Comment 2 Justin M. Forbes 2020-05-05 14:35:55 UTC

This was fixed for Fedora with the 5.5.10 stable kernel updates.

Comment 8 RaTasha Tillery-Smith 2020-05-19 12:43:51 UTC

Mitigation:

Mitigation for this issue is to skip loading the affected module mt76 onto the system until we have a fix available. This can be done by a blacklist mechanism and ensures the driver is not loaded at the boot time.
~~~
How do I blacklist a kernel module to prevent it from loading automatically?
https://access.redhat.com/solutions/41278 
~~~

Comment 9 errata-xmlrpc 2020-11-04 00:50:59 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2020:4431 https://access.redhat.com/errata/RHSA-2020:4431