Bug 2274572 (CVE-2021-47214)

Summary:	CVE-2021-47214 kernel: hugetlb, userfaultfd: fix reservation restore on userfaultfd error
Product:	[Other] Security Response	Reporter:	Marco Benatto <mbenatto>
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, jlelli, joe.lawrence, jshortt, jstancek, jwyatt, kcarcia, ldoskova, lgoncalv, lzampier, mleitner, mmilgram, mstowell, nmurray, ptalbert, rparrazo, rrobaina, rvrbovsk, rysulliv, scweaver, sidakwo, sukulkar, tglozar, tyberry, vkumar, wcosta, williams, wmealing, ycote, ykopkova, zhijwang
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	kernel 5.15.5, kernel 5.16	Doc Type:	If docs needed, set a value
Doc Text:	A vulnerability was found in the Linux kernel, in the handling of memory reservations in the hugetlb subsystem and userfaultfd. This issue occurs during the error-handling process in the hugetlb_mcopy_atomic_pte() function. When an error is encountered, the system incorrectly calls restore_reserve_on_error(), which improperly removes memory reservations. This leads to a memory leak, as the following call to remove_inode_hugepages() erroneously increments the reserved hugepages counter. This vulnerability was fully resolved by modifying the process to correctly handle the reservation state and avoid unnecessary deletion in the event of an error.	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:
Bug Blocks:	2274606

Description Marco Benatto 2024-04-11 19:19:45 UTC

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

hugetlb, userfaultfd: fix reservation restore on userfaultfd error

The Linux kernel CVE team has assigned CVE-2021-47214 to this issue.

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2024041005-CVE-2021-47214-59f9@gregkh/T

Comment 3 Alex 2024-06-09 12:47:03 UTC

The result of automatic check (that is developed by Alexander Larkin) for this CVE-2021-47214 is: 	SKIP	The Fixes patch not applied yet, so unlikely that actual: c7b1850dfb41d0b4154aca8dbc04777fbd75616f	YES			NO	YES	unknown (where first YES/NO value means if related sources built).