Bug 1822077 (CVE-2020-12826)

Summary: CVE-2020-12826 kernel: possible to send arbitrary signals to a privileged (suidroot) parent process
Product: [Other] Security Response Reporter: Dhananjay Arunesh <darunesh>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED ERRATA QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: acaringi, airlied, bhu, blc, bmasney, brdeoliv, bskeggs, carnil, dhoward, dvlasenk, esammons, fhrbata, hdegoede, hkrzesin, iboverma, ichavero, itamar, jarodwilson, jeremy, jforbes, jglisse, jlelli, john.j5live, jonathan, josef, jross, jshortt, jstancek, jwboyer, kcarcia, kernel-maint, kernel-mgr, lgoncalv, linville, masami256, matt, mchehab, mcressma, mjg59, mlangsdo, nmurray, ptalbert, qzhao, rt-maint, rvrbovsk, security-response-team, steved, williams, wmealing, yozone
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 loose validation of child/parent process identification handling while filtering signal handlers. A local attacker is able to abuse this flaw to bypass checks to send any signal to a privileged process.
Story Points: ---
Clone Of: Environment:
Last Closed: 2020-09-29 22:00:31 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: 1834649, 1834650, 1834651, 1834652, 1834653, 1834654    
Bug Blocks: 1818051    

Comment 2 Wade Mealing 2020-05-12 02:05:32 UTC
A flaw was found in the Linux kernel loose validation of child/parent process identification handling while filtering signal handlers.  A local attacker is able to abuse this flaw to bypass checks to send any signal to a privileged process.

The most likely attack vector is a local user attempting to attack a setuid process.

Comment 3 Wade Mealing 2020-05-12 05:42:24 UTC
Acknowledgments:

Name: Adam Zabrocki

Comment 6 Wade Mealing 2020-05-12 06:42:23 UTC
This flaw is rated as moderate, this may trigger a fault or possibly dos but there isnt a known memory corruption/privesc

Comment 7 Wade Mealing 2020-05-12 06:52:54 UTC
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1834649]

Comment 11 Justin M. Forbes 2020-05-12 17:15:46 UTC
This was fixed for Fedora with the 5.5.18 stable kernel updates.

Comment 12 Salvatore Bonaccorso 2020-05-13 06:41:23 UTC
This seems to be a duplicate of https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-12826 .

FWIW, issued via cveform.mitre.org a question on that to MITRE as well.

Comment 16 Petr Matousek 2020-05-15 14:55:56 UTC
In reply to comment #12:
> This seems to be a duplicate of
> https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-12826 .
> 
> FWIW, issued via cveform.mitre.org a question on that to MITRE as well.

thank you.

CVE-2020-10741 was rejected in favor of CVE-2020-12826. I added CVE-2020-12826 as a CVE alias for this bug.

Comment 17 Petr Matousek 2020-05-15 14:57:51 UTC
*** PLEASE NOTE ***

CVE-2020-10741 was rejected as per https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-10741 and CVE-2020-12826 should be used instead. based on that CVE-2020-10741 has been removed from this bug.

*** PLEASE NOTE ***

Comment 18 Petr Matousek 2020-05-26 12:58:03 UTC
Mitigation:

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Comment 19 errata-xmlrpc 2020-09-29 18:59:35 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2020:4062 https://access.redhat.com/errata/RHSA-2020:4062

Comment 20 errata-xmlrpc 2020-09-29 20:53:53 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2020:4060 https://access.redhat.com/errata/RHSA-2020:4060

Comment 21 Product Security DevOps Team 2020-09-29 22:00:31 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-2020-12826

Comment 37 errata-xmlrpc 2020-11-04 00:50:42 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2020:4431 https://access.redhat.com/errata/RHSA-2020:4431

Comment 38 errata-xmlrpc 2020-11-04 02:22:59 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2020:4609 https://access.redhat.com/errata/RHSA-2020:4609