CVE-2018-12232

In net/socket.c in the Linux kernel through 4.17.1, there is a race condition between fchownat and close in cases where they target the same socket file descriptor, related to the sock_close and sockfs_setattr functions. fchownat does not increment the file descriptor reference count, which allows close to set the socket to NULL during fchownat’s execution, leading to a NULL pointer dereference and system crash.

From the Ubuntu Security Team

Shankara Pailoor discovered that a race condition existed in the socket handling code in the Linux kernel. A local attacker could use this to cause a denial of service (system crash).

Status

Show unmaintained releases

Package	Ubuntu Release	Status
linux	18.10 cosmic	Not affected
	18.04 LTS bionic	Fixed 4.15.0-33.36
	17.10 artful	Ignored end of life
	16.04 LTS xenial	Not affected
	14.04 LTS trusty	Not affected
linux-aws	18.10 cosmic	Not affected
	18.04 LTS bionic	Fixed 4.15.0-1020.20
	17.10 artful	Not in release
	16.04 LTS xenial	Not affected
	14.04 LTS trusty	Not affected
linux-azure	18.10 cosmic	Not affected
	18.04 LTS bionic	Fixed 4.15.0-1022.23
	17.10 artful	Not in release
	16.04 LTS xenial	Fixed 4.15.0-1022.22~16.04.1
	14.04 LTS trusty	Not affected
linux-azure-edge	18.10 cosmic	Not in release
	18.04 LTS bionic	Not affected
	17.10 artful	Not in release
	16.04 LTS xenial	Fixed 4.15.0-1022.23
	14.04 LTS trusty	Not in release
linux-euclid	18.10 cosmic	Not in release
	18.04 LTS bionic	Not in release
	17.10 artful	Not in release
	16.04 LTS xenial	Ignored was needed ESM criteria
	14.04 LTS trusty	Not in release
linux-flo	18.10 cosmic	Not in release
	18.04 LTS bionic	Not in release
	17.10 artful	Not in release
	16.04 LTS xenial	Ignored abandoned
	14.04 LTS trusty	Not in release
linux-gcp	18.10 cosmic	Not affected
	18.04 LTS bionic	Fixed 4.15.0-1018.19
	17.10 artful	Not in release
	16.04 LTS xenial	Fixed 4.15.0-1018.19~16.04.2
	14.04 LTS trusty	Not in release
linux-gke	18.10 cosmic	Not in release
	18.04 LTS bionic	Not in release
	17.10 artful	Not in release
	16.04 LTS xenial	Ignored end of standard support, was needs-triage
	14.04 LTS trusty	Not in release
linux-goldfish	18.10 cosmic	Not in release
	18.04 LTS bionic	Not in release
	17.10 artful	Not in release
	16.04 LTS xenial	Ignored end of life, was needs-triage
	14.04 LTS trusty	Not in release
linux-grouper	18.10 cosmic	Not in release
	18.04 LTS bionic	Not in release
	17.10 artful	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-hwe	18.10 cosmic	Not in release
	18.04 LTS bionic	Not affected
	17.10 artful	Not in release
	16.04 LTS xenial	Fixed 4.15.0-33.36~16.04.1
	14.04 LTS trusty	Not in release
linux-hwe-edge	18.10 cosmic	Not in release
	18.04 LTS bionic	Not affected
	17.10 artful	Not in release
	16.04 LTS xenial	Fixed 4.15.0-33.36~16.04.1
	14.04 LTS trusty	Not in release
linux-kvm	18.10 cosmic	Not affected
	18.04 LTS bionic	Fixed 4.15.0-1020.20
	17.10 artful	Not in release
	16.04 LTS xenial	Not affected
	14.04 LTS trusty	Not in release
linux-lts-trusty	18.10 cosmic	Not in release
	18.04 LTS bionic	Not in release
	17.10 artful	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-lts-utopic	18.10 cosmic	Not in release
	18.04 LTS bionic	Not in release
	17.10 artful	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-lts-vivid	18.10 cosmic	Not in release
	18.04 LTS bionic	Not in release
	17.10 artful	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-lts-wily	18.10 cosmic	Not in release
	18.04 LTS bionic	Not in release
	17.10 artful	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-lts-xenial	18.10 cosmic	Not in release
	18.04 LTS bionic	Not in release
	17.10 artful	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not affected
linux-maguro	18.10 cosmic	Not in release
	18.04 LTS bionic	Not in release
	17.10 artful	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-mako	18.10 cosmic	Not in release
	18.04 LTS bionic	Not in release
	17.10 artful	Not in release
	16.04 LTS xenial	Ignored abandoned
	14.04 LTS trusty	Not in release
linux-manta	18.10 cosmic	Not in release
	18.04 LTS bionic	Not in release
	17.10 artful	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
linux-oem	18.10 cosmic	Not affected
	18.04 LTS bionic	Fixed 4.15.0-1017.20
	17.10 artful	Not in release
	16.04 LTS xenial	Ignored end of standard support, was needed
	14.04 LTS trusty	Not in release
linux-raspi2	18.10 cosmic	Not affected
	18.04 LTS bionic	Fixed 4.15.0-1021.23
	17.10 artful	Ignored end of life
	16.04 LTS xenial	Not affected
	14.04 LTS trusty	Not in release
linux-snapdragon	18.10 cosmic	Not in release
	18.04 LTS bionic	Not affected
	17.10 artful	Ignored end of life
	16.04 LTS xenial	Not affected
	14.04 LTS trusty	Not in release

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
linux	Introduced by 86741ec, fixed by 6d8c50d

Severity score breakdown

Parameter	Value
Base score	5.9 · Medium
Attack vector	Network
Attack complexity	High
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality	None
Integrity impact	None
Availability impact	High
Vector	CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

References

Related Ubuntu Security Notices (USN)

USN-3752-2
Linux kernel (HWE) vulnerabilities
24 August 2018

USN-3752-1
Linux kernel vulnerabilities
24 August 2018

USN-3752-3
Linux kernel (Azure, GCP, OEM) vulnerabilities
28 August 2018