Bug 1694758 (CVE-2019-9857)

Summary:	CVE-2019-9857 kernel: memory leak in inotify_update_existing_watch() leads to denial of service
Product:	[Other] Security Response	Reporter:	msiddiqu
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	acaringi, airlied, bhu, blc, brdeoliv, bskeggs, dhoward, dvlasenk, fhrbata, hdegoede, hkrzesin, iboverma, ichavero, itamar, jarodwilson, jeremy, jforbes, jglisse, jkacur, john.j5live, jonathan, josef, jross, jstancek, jwboyer, kernel-maint, kernel-mgr, labbott, lgoncalv, linville, matt, mchehab, mcressma, mjg59, mlangsdo, nmurray, plougher, 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 in the inotify subsystem can allow a local attacker to create a denial of service (DOS) situation in which the memory use of watches on existing watchpoints were not accounted for correctly.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2019-07-31 13:52:14 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:	1694759, 1711174, 1711178, 1711179
Bug Blocks:	1694762

Description msiddiqu 2019-04-01 15:13:41 UTC

In the Linux kernel through 5.0.2, the function inotify_update_existing_watch() in fs/notify/inotify/inotify_user.c neglects to call fsnotify_put_mark() with IN_MASK_CREATE after fsnotify_find_mark(), which will cause a memory leak (aka refcount leak). Finally, this will cause a denial of service.

Upstream patch: 
https://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs.git/commit/?h=fsnotify&id=62c9d2674b31d4c8a674bee86b7edc6da2803aea

References:  
https://patchwork.kernel.org/patch/10836283/

Comment 1 msiddiqu 2019-04-01 15:13:58 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1694759]

Comment 2 Fedora Update System 2019-04-09 01:13:29 UTC

kernel-5.0.6-100.fc28, kernel-headers-5.0.6-100.fc28, kernel-tools-5.0.6-100.fc28 has been pushed to the Fedora 28 stable repository. If problems still persist, please make note of it in this bug report.

Comment 3 Fedora Update System 2019-04-09 02:19:06 UTC

kernel-5.0.6-200.fc29, kernel-headers-5.0.6-200.fc29, kernel-tools-5.0.6-200.fc29 has been pushed to the Fedora 29 stable repository. If problems still persist, please make note of it in this bug report.