Bug 1669141 (CVE-2018-20669)

Summary:	CVE-2018-20669 kernel: missing access_ok() checks in i915_gem_execbuffer2_ioctl() results in priviledge escalation
Product:	[Other] Security Response	Reporter:	msiddiqu
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	abhgupta, acaringi, bhu, blc, dbaker, dhoward, hkrzesin, hwkernel-mgr, iboverma, jforbes, jkacur, joe.lawrence, jokerman, jross, kernel-mgr, lgoncalv, mcressma, mlangsdo, nmurray, rt-maint, sthangav, trankin, vdronov, williams, yozone
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 flaw was found in the Linux kernel where a provided address with access_ok() is not checked before accessing userspace data in certain situations. Lack of such checks in i915_gem_execbuffer2_ioctl in drivers/gpu/drm/i915/i915_gem_execbuffer.c may allow a local unprivileged attacker to possible escalate its privileges.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2021-10-27 03:23:47 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:	1669142, 1670112, 1670113, 1670114
Bug Blocks:	1669143

Description msiddiqu 2019-01-24 12:39:15 UTC

Linux kernel is not checking a provided address with access_ok() when accessing userspace data in certain situations. Lack of such checks in i915_gem_execbuffer2_ioctl in drivers/gpu/drm/i915/i915_gem_execbuffer.c may allow a local unprivileged attacker to possible escalate its privileges.

References:

https://salls.github.io/Linux-Kernel-CVE-2017-5123/ (missing access_ok() check described)

Upstream patch:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=594cc251fdd0d231d342d88b2fdff4bc42fb0690

Comment 1 msiddiqu 2019-01-24 12:40:03 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1669142]

Comment 2 Justin M. Forbes 2019-01-24 13:10:20 UTC

This is fixed for Fedora with the 4.20.{3,4} kernel rebases.