Bug 2266407 (CVE-2021-46908)

Summary:	CVE-2021-46908 kernel: unknown scalars with mixed signed bounds masking mitigation
Product:	[Other] Security Response	Reporter:	Rohit Keshri <rkeshri>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	acaringi, allarkin, aquini, bhu, chwhite, cye, cyin, dbohanno, debarbos, dfreiber, drow, dvlasenk, esandeen, ezulian, hkrzesin, jarod, jburrell, jdenham, jfaracco, jforbes, jlelli, joe.lawrence, jshortt, jstancek, jwyatt, kcarcia, ldoskova, lgoncalv, lzampier, mleitner, mmilgram, mstowell, nmurray, ptalbert, rparrazo, rrobaina, rvrbovsk, rysulliv, scweaver, sukulkar, tglozar, tyberry, vkumar, wcosta, williams, wmealing, ycote, ykopkova, zhijwang
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. Adding unknown scalars with mixed signed bounds are forbidden due to the spectre v1 masking mitigation. Therefore, this needs the bypass_spec_v1 flag instead of allow_ptr_leaks.	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:	2266410
Bug Blocks:	2266369

Description Rohit Keshri 2024-02-27 18:53:57 UTC

In the Linux kernel, the following vulnerability has been resolved:

bpf: Use correct permission flag for mixed signed bounds arithmetic

We forbid adding unknown scalars with mixed signed bounds due to the
spectre v1 masking mitigation. Hence this also needs bypass_spec_v1
flag instead of allow_ptr_leaks.

https://git.kernel.org/stable/c/4ccdc6c6cae38b91c871293fb0ed8c6845a61b51
https://git.kernel.org/stable/c/4f3ff11204eac0ee23acf64deecb3bad7b0db0c6
https://git.kernel.org/stable/c/9601148392520e2e134936e76788fc2a6371e7be

Comment 1 Rohit Keshri 2024-02-27 18:57:30 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 2266410]

Comment 3 Justin M. Forbes 2024-02-27 23:11:11 UTC

This was fixed for Fedora with the 5.11.16 stable kernel updates.