Bug 1903262 (CVE-2020-29369)

Summary: CVE-2020-29369 kernel: race condition between expand_downwards and expand_upwards and page-table free operations from an munmap call
Product: [Other] Security Response Reporter: Guilherme de Almeida Suckevicz <gsuckevi>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED NOTABUG QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: acaringi, adscvr, airlied, aquini, asavkov, bhu, blc, bmasney, brdeoliv, bskeggs, dhoward, dvlasenk, esammons, fhrbata, hdegoede, hkrzesin, iboverma, itamar, jarodwilson, jeremy, jforbes, jglisse, jlelli, joe.lawrence, jonathan, josef, jpoimboe, jross, jshortt, jstancek, jthierry, jwboyer, kcarcia, kernel-maint, kernel-mgr, kpatch-maint, lgoncalv, linville, masami256, mchehab, mcressma, mjg59, mlangsdo, nmurray, ptalbert, qzhao, rhandlin, rt-maint, rvrbovsk, steved, walters, williams, wmealing, ycote
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Fixed In Version: Doc Type: If docs needed, set a value
Doc Text:
A flaw was found in the Linux kernel. A race condition between certain expand functions and page-table free operations from an munmap call leading to ... FIXME. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
Story Points: ---
Clone Of: Environment:
Last Closed: 2020-12-07 15:36:09 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Bug Depends On: 1903263, 1903473, 1903474, 1903475, 1903476, 1903477, 1903478, 1903479, 1903480, 1903481, 1903482, 1903484, 1903485, 1903486, 1903487, 1903488, 1903489, 1903490, 1903491, 1903492, 1903493, 1903494, 1903495    
Bug Blocks: 1903264    

Description Guilherme de Almeida Suckevicz 2020-12-01 17:39:43 UTC
An issue was discovered in mm/mmap.c in the Linux kernel before 5.7.11. There is a race condition between certain expand functions (expand_downwards and expand_upwards) and page-table free operations from an munmap call.


Upstream patch:

Comment 1 Guilherme de Almeida Suckevicz 2020-12-01 17:40:32 UTC
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1903263]

Comment 6 Wade Mealing 2020-12-02 08:15:40 UTC

There is no mitigation available at this time.  Red Hat is investigating a kpatch as an option to fix this issue on kpatch supported streams.

Comment 8 Justin M. Forbes 2020-12-02 14:20:28 UTC
This was fixed for Fedora with the 5.7.11 stable kernel updates.

Comment 15 Wade Mealing 2020-12-03 03:35:12 UTC
Removing needinfo as I think most of them are no longer relevant.