Bug 1852942 (CVE-2019-20908)

Summary: CVE-2019-20908 kernel: lockdown: bypass through ACPI write via efivar_ssdt
Product: [Other] Security Response Reporter: Petr Matousek <pmatouse>
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, dhoward, dvlasenk, esammons, fhrbata, gsuckevi, hdegoede, hkrzesin, iboverma, ichavero, itamar, jarodwilson, jeremy, jforbes, jglisse, jlelli, john.j5live, jonathan, josef, jross, jshortt, jstancek, jwboyer, kcarcia, kernel-maint, kernel-mgr, labbott, lgoncalv, linville, masami256, matt, mchehab, mcressma, mjg59, mlangsdo, nmurray, ptalbert, qzhao, rt-maint, rvrbovsk, steved, williams
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 how the ACPI table loading through the EFI variable (and the related efivar_ssdt boot option) was handled when the Linux kernel was locked down. This flaw allows a (root) privileged local user to circumvent the kernel lockdown restrictions. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
Story Points: ---
Clone Of: Environment:
Last Closed: 2020-07-29 19:27:57 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: 1852944, 1852946, 1852947, 1852948, 1852949, 1852950, 1852951, 1852952, 1852953    
Bug Blocks: 1848170    

Description Petr Matousek 2020-07-01 16:10:47 UTC
A flaw was found in the way ACPI table loading through EFI variable (and related efivar_ssdt boot option) was handled when the Linux kernel was locked down. A (root) privileged local user could use this flaw to circumvent the kernel lockdown restrictions.

Comment 2 Petr Matousek 2020-07-01 16:10:55 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 3 Petr Matousek 2020-07-01 16:14:18 UTC
Statement:

This issue is rated as having Moderate impact because of the privileges required for exploitation.

Comment 4 Petr Matousek 2020-07-01 16:15:04 UTC
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1852944]

Comment 9 Guilherme de Almeida Suckevicz 2020-07-17 12:40:28 UTC
*** Bug 1857859 has been marked as a duplicate of this bug. ***

Comment 10 errata-xmlrpc 2020-07-29 18:29:21 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2020:3218 https://access.redhat.com/errata/RHSA-2020:3218

Comment 11 errata-xmlrpc 2020-07-29 18:29:58 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2020:3219 https://access.redhat.com/errata/RHSA-2020:3219

Comment 12 Product Security DevOps Team 2020-07-29 19:27:57 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-2019-20908

Comment 13 errata-xmlrpc 2020-07-29 19:37:35 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.1 Extended Update Support

Via RHSA-2020:3222 https://access.redhat.com/errata/RHSA-2020:3222

Comment 14 errata-xmlrpc 2020-07-29 20:17:08 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.0 Update Services for SAP Solutions

Via RHSA-2020:3228 https://access.redhat.com/errata/RHSA-2020:3228