Bug 2213149 (CVE-2023-31085)

Summary:	CVE-2023-31085 kernel: divide-by-zero error in ctrl_cdev_ioctl when do_div happens and erasesize is 0
Product:	[Other] Security Response	Reporter:	Alex <allarkin>
Component:	vulnerability	Assignee:	Nobody <nobody>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	acaringi, allarkin, bhu, chwhite, crwood, dbohanno, ddepaula, debarbos, dfreiber, dvlasenk, ezulian, hkrzesin, jarod, jburrell, jdenham, jfaracco, jferlan, jforbes, jlelli, joe.lawrence, jshortt, jstancek, jwyatt, kcarcia, kernel-mgr, ldoskova, lgoncalv, lzampier, nmurray, ptalbert, qzhao, rogbas, rrobaina, rvrbovsk, rysulliv, scweaver, steve.beattie, tyberry, vkumar, walters, wcosta, williams, wmealing, ycote
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 divide-by-zero flaw was found in the Linux kernel’s UBI (a software layer above the MTD layer that admits the use of LVM-like logical volumes on top of MTD devices). This flaw allows a local user to crash the system.	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:	2213150, 2213152, 2213153, 2213154, 2213155
Bug Blocks:	2189448

Description Alex 2023-06-07 08:38:14 UTC

A flaw in the Linux Kernel found in drivers/mtd/ubi/cdev.c. There is a divide-by-zero error in do_div(sz,mtd->erasesize), used indirectly by ctrl_cdev_ioctl, when mtd->erasesize is 0.

Reference:
https://lore.kernel.org/all/CA+UBctD_w=75wChmePZHp7KsBSNPWYGDBtzHPRPPtaFoqhGvXA@mail.gmail.com/

Comment 1 Alex 2023-06-07 08:38:40 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 2213150]

Comment 5 Justin M. Forbes 2023-11-08 18:33:41 UTC

This was fixed for Fedora with the 6.5.7 stable kernel updates.