Bug 1790063 (CVE-2019-20054)

Summary:	CVE-2019-20054 kernel: Null pointer dereference in drop_sysctl_table() in fs/proc/proc_sysctl.c
Product:	[Other] Security Response	Reporter:	Pedro Sampaio <psampaio>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	acaringi, airlied, bhu, blc, brdeoliv, bskeggs, dhoward, dvlasenk, esammons, fhrbata, hdegoede, hkrzesin, iboverma, ichavero, itamar, jarodwilson, jeremy, jforbes, jglisse, jlelli, john.j5live, jonathan, josef, jross, jshortt, jstancek, jwboyer, kernel-maint, kernel-mgr, labbott, lgoncalv, linville, masami256, matt, mchehab, mcressma, mjg59, mlangsdo, nmurray, qzhao, rt-maint, rvrbovsk, steved, williams, wmealing
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’s implementation of dropping sysctl entries. A local attacker who has access to load modules on the system can trigger a condition during module load failure and panic the system.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2020-04-16 16:32:05 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:	1790064, 1795518, 1795519, 1795520, 1795521, 1795522, 1795523, 1795828
Bug Blocks:	1790067

Description Pedro Sampaio 2020-01-11 15:16:10 UTC

A flaw was found in the Linux kernels implementation of dropping sysctl entries.  The case where insert_header() fails the parent pointer may still be set to null and then accessed.

This operation is usually invoked during a module load (a local, privileged operation) and requires a failure mode to take place.  It is unlikely to be able to be used successfully as an attack vector. 



Upstream patch:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=23da9588037ecdd4901db76a5b79a42b529c4ec3
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=89189557b47b35683a27c80ee78aef18248eefb4

References:

https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.0.11
https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.0.6

Comment 1 Pedro Sampaio 2020-01-11 15:16:40 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1790064]

Comment 2 Justin M. Forbes 2020-01-13 12:58:59 UTC

This was fixed for Fedora with the 5.0.6 stable updates.

Comment 9 errata-xmlrpc 2020-04-16 14:38:50 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2020:1493 https://access.redhat.com/errata/RHSA-2020:1493

Comment 10 Product Security DevOps Team 2020-04-16 16:32:05 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-2019-20054

Comment 11 errata-xmlrpc 2020-09-29 18:59:00 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 12 errata-xmlrpc 2020-09-29 20:53:01 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 28 errata-xmlrpc 2020-11-04 00:50:23 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 29 errata-xmlrpc 2020-11-04 02:22:30 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