Bug 2031928 (CVE-2021-1048)

Summary:	CVE-2021-1048 kernel: Use After Free in epoll_loop_check_proc() which could result in a local privilege escalation
Product:	[Other] Security Response	Reporter:	Michael Kaplan <mkaplan>
Component:	vulnerability	Assignee:	Nobody <nobody>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	acaringi, adscvr, airlied, alciregi, arachman, bdettelb, bhu, chwhite, cmaiolin, crwood, dfreiber, doconnor, drow, dvlasenk, esandeen, hdegoede, hkrzesin, jarod, jarodwilson, jburrell, jeremy, jfaracco, jforbes, jglisse, jlelli, joe.lawrence, jonathan, josef, jpoimboe, jshortt, jstancek, jthierry, jwboyer, kcarcia, kernel-maint, kernel-mgr, kpatch-maint-bot, lgoncalv, linville, lveyde, lzampier, masami256, mchehab, michal.skrivanek, mperina, nmurray, nobody, ptalbert, qzhao, rhandlin, rkeshri, rogbas, rvrbovsk, scweaver, steved, teagle, vkumar, walters, williams, ycote
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	kernel 5.9 rc4	Doc Type:	If docs needed, set a value
Doc Text:	A use-after-free flaw was found in Linux kernel's ep_loop_check_proc in fs/eventpoll.c function in the filesystem. This flaw could allow an attacker to crash the system while polling for a file that is already committed to destruction. This vulnerability could lead to a kernel information leak and a privilege escalation problem.	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:	2032650, 2031929, 2031942, 2031943, 2031944, 2031945, 2031946, 2031947, 2031948, 2031949, 2031950, 2031951, 2031952, 2031953, 2031954, 2032817
Bug Blocks:	2030656

Description Michael Kaplan 2021-12-13 17:52:22 UTC

A use-after-free flaw was found in ep_loop_check_proc in fs/eventpoll.c in the filesystem. This flaw could allow an attacker to crash the system while polling for a file that is already committed to destruction. This vulnerability could lead to a kernel information leak and a privilege escalation problem.

References:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=77f4689de17c0887775bb77896f4cc11a39bf848

Comment 1 Michael Kaplan 2021-12-13 17:53:01 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 2031929]

Comment 13 Justin M. Forbes 2021-12-16 15:51:16 UTC

This was fixed for Fedora with the 5.8.8 stable kernel updates.