Bug 1882594 (CVE-2020-25284)

Summary:	CVE-2020-25284 kernel: incomplete permission checking for access to rbd devices
Product:	[Other] Security Response	Reporter:	Dhananjay Arunesh <darunesh>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	acaringi, airlied, bhu, blc, bmasney, brdeoliv, bskeggs, 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, mchehab, mcressma, mjg59, mlangsdo, nmurray, ptalbert, qzhao, rt-maint, rvrbovsk, sgrubb, 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 the capabilities check of the rados block device functionality in the Linux kernel. Incorrect capability checks could alllow a local user with root priviledges (but no capabilities) to add or remove Rados Block Devices from the system.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2021-05-18 20:36:25 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:	1882595, 1887327, 1887328, 1887329, 1887330
Bug Blocks:	1882593

Description Dhananjay Arunesh 2020-09-25 04:45:37 UTC

The rbd block device driver in drivers/block/rbd.c in the Linux kernel used incomplete permission checking for access to rbd devices, which could be leveraged by local attackers to map or unmap rbd block devices.

References:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f44d04e696feaf13d192d942c4f14ad2e117065a

Comment 1 Dhananjay Arunesh 2020-09-25 04:46:26 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1882595]

Comment 3 Justin M. Forbes 2020-09-25 12:33:36 UTC

This was fixed for Fedora with the 5.8.10 stable kernel updates.

Comment 6 Wade Mealing 2020-10-08 04:00:48 UTC

Mitigation:


As the rbd module can be loaded by a priviledged user or process, its use can be disabled by preventing the module from loading with the following instructions:

# echo "install rbd /bin/true" >> /etc/modprobe.d/disable-rdb.conf 
 
The system will need to be restarted if the modules isloaded. In most circumstances, the rbd kernel modules will be unable to be unloaded while in use.

If the system requires this module to work correctly, (Such as a CEPH node) this mitigation may not be suitable.

If you need further assistance, see KCS article https://access.redhat.com/solutions/41278 or contact Red Hat Global Support Services.

Comment 9 errata-xmlrpc 2021-05-18 13:20:28 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2021:1578 https://access.redhat.com/errata/RHSA-2021:1578

Comment 10 errata-xmlrpc 2021-05-18 14:40:47 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2021:1739 https://access.redhat.com/errata/RHSA-2021:1739

Comment 11 Product Security DevOps Team 2021-05-18 20:36:25 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-2020-25284