Bug 2219266 (CVE-2023-2861)

Summary:	CVE-2023-2861 QEMU: 9pfs: improper access control on special files
Product:	[Other] Security Response	Reporter:	TEJ RATHI <trathi>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	ddepaula, jen, jferlan, jmaloy, knoel, mkenneth, mrezanin, mst, pbonzini, virt-maint, ymankad
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	qemu-kvm 8.1.0	Doc Type:	If docs needed, set a value
Doc Text:	A flaw was found in the 9p passthrough filesystem (9pfs) implementation in QEMU. The 9pfs server did not prohibit opening special files on the host side, potentially allowing a malicious client to escape from the exported 9p tree by creating and opening a device file in the shared folder.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2023-07-04 07:46:01 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:	2219306
Bug Blocks:	2175653

Description TEJ RATHI 2023-07-03 06:57:40 UTC

The 9p protocol does not specifically define how server shall behave when client tries to open a special file, however from security POV it does make sense for 9p server to prohibit opening any special file on host side in general. A sane Linux 9p client for instance would never attempt to open a special file on host side, it would always handle those exclusively on its guest side. A malicious client however could potentially escape from the exported 9p tree by creating and opening a device file on host side.

https://gitlab.com/qemu-project/qemu/-/commit/f6b0de53fb87ddefed348a39284c8e2f28dc4eda

Comment 1 Mauro Matteo Cascella 2023-07-03 08:03:12 UTC

Created qemu tracking bugs for this issue:

Affects: fedora-all [bug 2219306]

Comment 2 Product Security DevOps Team 2023-07-04 07:45:59 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-2023-2861