Bug 1760958 (CVE-2019-15921)

Summary:	CVE-2019-15921 kernel: memory leak in genl_register_family() in net/netlink/genetlink.c
Product:	[Other] Security Response	Reporter:	Guilherme de Almeida Suckevicz <gsuckevi>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	acaringi, airlied, bdettelb, bhu, blc, brdeoliv, bskeggs, dhoward, dvlasenk, esammons, fhrbata, hdegoede, hkrzesin, iboverma, ichavero, itamar, jarodwilson, jeremy, jforbes, jglisse, jlelli, john.j5live, jonathan, josef, jross, jschorr, jshortt, jstancek, jwboyer, kernel-maint, kernel-mgr, labbott, lgoncalv, linville, masami256, matt, mchehab, mcressma, mjg59, mlangsdo, nmurray, plougher, rt-maint, rvrbovsk, 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 genl_register_family function in the Linux kernel. An attacker able to induce the error conditions could use this flaw to crash the system. The highest threat from this vulnerability is to system availability.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2020-04-30 17:47:13 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:	1760960
Bug Blocks:	1760962

Description Guilherme de Almeida Suckevicz 2019-10-11 19:58:47 UTC

An issue was discovered in the Linux kernel before 5.0.6. There is a memory leak issue when idr_alloc() fails in genl_register_family() in net/netlink/genetlink.c.

Reference:
https://github.com/torvalds/linux/commit/ceabee6c59943bdd5e1da1a6a20dc7ee5f8113a2

Comment 1 Guilherme de Almeida Suckevicz 2019-10-11 20:08:34 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1760960]

Comment 2 Justin M. Forbes 2019-10-16 16:17:58 UTC

This was fixed for Fedora with the 5.0.6 stable kernel updates.

Comment 6 Petr Matousek 2020-04-30 17:39:45 UTC

Mitigation:

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Comment 7 Petr Matousek 2020-04-30 17:45:06 UTC

Statement:

This issue is rated as having Low impact because of the preconditions needed to trigger the error/resource cleanup code path (system-wide out-of-memory condition, high privileges or physical access). The generic netlink is a way for kernel modues to easily communicate with userspace using netlink. genl_register_family is thus called by kernel modules (code) only and it's hard for an attacker to invoke (module reloads?) it let alone fail on the right place.