Bug 1794404 (CVE-2019-19965)

Summary:	CVE-2019-19965 kernel: NULL pointer dereference in drivers/scsi/libsas/sas_discover.c because of mishandling of port disconnection during discovery
Product:	[Other] Security Response	Reporter:	Guilherme de Almeida Suckevicz <gsuckevi>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	acaringi, airlied, bhu, blc, brdeoliv, bskeggs, dhoward, dvlasenk, esammons, fhrbata, hdegoede, hkrzesin, iboverma, ichavero, itamar, jarodwilson, jeremy, jforbes, jlelli, john.j5live, jonathan, josef, jross, jshortt, jstancek, jwboyer, kernel-maint, kernel-mgr, lgoncalv, linville, masami256, mchehab, mcressma, mjg59, mlangsdo, nmurray, qzhao, 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 NULL pointer dereference flaw was found in the Linux kernel’s SCSI disk subsystem. A local user could use this flaw to crash the system, causing a denial of service.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2021-12-15 11:14:08 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:	1890042, 1890043, 1890044, 1890045, 1890046, 1794405, 1812039, 1812040, 1812041, 1812042, 1812043
Bug Blocks:	1794406

Description Guilherme de Almeida Suckevicz 2020-01-23 14:14:40 UTC

In the Linux kernel through 5.4.6, there is a NULL pointer dereference in drivers/scsi/libsas/sas_discover.c because of mishandling of port disconnection during discovery, related to a PHY down race condition.

Reference and upstream commit:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f70267f379b5e5e11bdc5d72a56bf17e5feed01f

Comment 1 Guilherme de Almeida Suckevicz 2020-01-23 14:15:28 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1794405]

Comment 2 Justin M. Forbes 2020-01-23 19:13:11 UTC

This is fixed for Fedora with the 5.4.9 stable kernel update.

Comment 5 Alex 2020-03-10 17:22:47 UTC

Mitigation:

To mitigate this issue, prevent module libsas from being loaded. Please see https://access.redhat.com/solutions/41278 for how to blacklist a kernel module to prevent it from loading automatically.