Bug 2379180 (CVE-2025-38306)

Summary:	CVE-2025-38306 kernel: Linux kernel: Race condition leads to Denial of Service
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	rhel-process-autobot, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the Linux kernel. A local attacker with low privileges could exploit a race condition in the `has_locked_children()` function within `fs/fhandle.c`. This could lead to a system crash, resulting in a Denial of Service (DoS).	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2025-07-10 08:01:55 UTC

In the Linux kernel, the following vulnerability has been resolved:

fs/fhandle.c: fix a race in call of has_locked_children()

may_decode_fh() is calling has_locked_children() while holding no locks.
That's an oopsable race...

The rest of the callers are safe since they are holding namespace_sem and
are guaranteed a positive refcount on the mount in question.

Rename the current has_locked_children() to __has_locked_children(), make
it static and switch the fs/namespace.c users to it.

Make has_locked_children() a wrapper for __has_locked_children(), calling
the latter under read_seqlock_excl(&mount_lock).

Comment 1 Avinash Hanwate 2025-07-11 11:49:29 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025071014-CVE-2025-38306-66ae@gregkh/T