Bug 1550818 (CVE-2017-18204)

Summary:	CVE-2017-18204 kernel: Deadlock caused in fs/ocfs2/file.c:ocfs2_setattr() can allow local users to cause a denial of service
Product:	[Other] Security Response	Reporter:	Sam Fowler <sfowler>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	aquini, bhu, blc, dhoward, esammons, fhrbata, hkrzesin, hwkernel-mgr, iboverma, jforbes, jkacur, jross, kernel-mgr, lgoncalv, lwang, matt, mcressma, mguzik, mlangsdo, nmurray, plougher, rt-maint, rvrbovsk, skozina, vdronov, williams, yozone
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	kernel 4.14.2	Doc Type:	If docs needed, set a value
Doc Text:	The Linux kernel, before version 4.14.2, is vulnerable to a deadlock caused by fs/ocfs2/file.c:ocfs2_setattr(), as the function does not wait for DIO requests before locking the inode. This can be exploited by local users to cause a subsequent denial of service.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2018-03-05 10:18:37 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:	1551505
Bug Blocks:	1550819

Description Sam Fowler 2018-03-02 05:23:25 UTC

The Linux kernel before version 4.14.2 is vulnerable to a deadlock caused by fs/ocfs2/file.c:ocfs2_setattr(), as the function does not wait for DIO requests before locking the inode. This can be exploited by local users to cause a subsequent denial of service.

References:

https://marc.info/?t=150943101800001&r=1&w=2

An upstream patch:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=28f5a8a7c033cbf3e32277f4cc9c6afd74f05300

Comment 3 Vladis Dronov 2018-03-05 10:12:30 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1551505]

Comment 4 Vladis Dronov 2018-03-05 10:18:37 UTC

Statement:

This issue does not affect the versions of the Linux kernel as shipped with Red Hat Enterprise Linux 5, 6, 7, its real-time kernel, Red Hat Enterprise MRG 2, Red Hat Enterprise Linux 7 for ARM 64 and Red Hat Enterprise Linux 7 for Power 9 LE, as the code with the flaw is not built and shipped in the products listed.

Comment 5 Justin M. Forbes 2018-03-05 12:37:30 UTC

This was fixed for Fedora with the 4.14.2 stable updates.