Bug 2026484 (CVE-2021-4023)

Summary: CVE-2021-4023 kernel: Improper IO-uring request cancellation operation allows local users to cause a crash
Product: [Other] Security Response Reporter: Pedro Sampaio <psampaio>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED NOTABUG QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: acaringi, adscvr, airlied, alciregi, bhu, 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, nmurray, ptalbert, qzhao, rvrbovsk, steved, vkumar, walters, williams
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: kernel 5.15rc1 Doc Type: If docs needed, set a value
Doc Text:
A flaw was found in the io-workqueue implementation in the Linux kernel. The kernel can panic when an improper cancellation operation triggers the submission of new io-uring operations during a shortage of free space. This flaw allows a local user with permissions to execute io-uring requests to possibly crash the system.
 Story Points: ---
Clone Of: Environment:
Last Closed: 2021-11-26 15:54:34 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: 2026810    
Bug Blocks: 2026547, 2026790    

Description Pedro Sampaio 2021-11-24 19:57:30 UTC 
A flaw was found in the io-workqueue implementation in the Linux kernel. The kernel can panic when an improper cancellation operation triggers the submission of new io-uring operations during  a shortage of free space.   This allows a local user with permissions to execute io-uring requests to possible crash the system.

Statement:

Red Hat has not implemented io-uring in any shipping products however it appears to be enabled in the Fedora Project.

References:

https://git.kernel.dk/cgit/linux-block/commit/?h=io_uring-5.15&id=713b9825a4c47897f66ad69409581e7734a8728e
https://lkml.org/lkml/2021/9/8/64
Comment 5 Wade Mealing 2021-11-26 01:32:24 UTC 
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 2026810]
Comment 6 Product Security DevOps Team 2021-11-26 15:54:30 UTC 
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):

https://access.redhat.com/security/cve/cve-2021-4023
Comment 7 Justin M. Forbes 2021-11-29 17:33:23 UTC 
This was fixed for Fedora with the 5.14.6 stable kernel updates.