Bug 2007567 (CVE-2021-41073)

Summary:	CVE-2021-41073 kernel: local user privilege escalation via loop_rw_iter in fs/io_uring.c
Product:	[Other] Security Response	Reporter:	Marian Rehak <mrehak>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	acaringi, adscvr, airlied, alciregi, bdettelb, bhu, blc, brdeoliv, bskeggs, chwhite, crwood, dhoward, dvlasenk, fhrbata, fpacheco, hdegoede, hkrzesin, jarod, jarodwilson, jburrell, jeremy, jforbes, jglisse, jlelli, jonathan, josef, jshortt, jstancek, jwboyer, kcarcia, kernel-maint, kernel-mgr, lgoncalv, linville, masami256, mchehab, mlangsdo, nmurray, ptalbert, qzhao, rvrbovsk, steved, vkumar, walters, williams
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	Linux kernel 5.15rc2	Doc Type:	If docs needed, set a value
Doc Text:	A flaw was found in loop_rw_iter in fs/io_uring.c in the Linux kernel. This problem gives the ability to a local user with a normal user privilege to free a user-defined kernel space buffer.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2021-09-30 09:53:32 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:	2007568, 2008611
Bug Blocks:	2007569

Description Marian Rehak 2021-09-24 09:47:22 UTC

loop_rw_iter in fs/io_uring.c in the Linux kernel allows local users to gain privileges by using IORING_OP_PROVIDE_BUFFERS to trigger a free of a kernel buffer.

External reference:

https://www.openwall.com/lists/oss-security/2021/09/18/2

Comment 1 Marian Rehak 2021-09-24 09:50:30 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 2007568]

Comment 4 Rohit Keshri 2021-09-28 17:05:09 UTC

There was no shipped kernel version that was seen affected by this problem. These files are not built in our source code.