CVE-2018-1000200

The Linux Kernel versions 4.14, 4.15, and 4.16 has a null pointer dereference which can result in an out of memory (OOM) killing of large mlocked processes. The issue arises from an oom killed process's final thread calling exit_mmap(), which calls munlock_vma_pages_all() for mlocked vmas.This can happen synchronously with the oom reaper's unmap_page_range() since the vma's VM_LOCKED bit is cleared before munlocking (to determine if any other vmas share the memory and are mlocked).

From the Ubuntu Security Team

It was discovered that, when attempting to handle an out-of-memory situation, a null pointer dereference could be triggered in the Linux kernel in some circumstances. A local attacker could use this to cause a denial of service (system crash).

Read the notes from the security team

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	Not affected
	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
	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	Not affected
	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	Not affected
	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	Not affected
	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	Not affected
	16.04 LTS xenial	Not affected
	14.04 LTS trusty	Not in release

Notes

tyhicks

Proposed fix (v2): https://marc.info/?l=linux-kernel&m=152401997210084&w=2 Proposed fix (v3): https://marc.info/?l=linux-kernel&m=152460926619256

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 2129258, fixed by 27ae357

Severity score breakdown

Parameter	Value
Base score	5.5 · Medium
Attack vector	Local
Attack complexity	Low
Privileges required	Low
User interaction	None
Scope	Unchanged
Confidentiality	None
Integrity impact	None
Availability impact	High
Vector	CVSS:3.0/AV:L/AC:L/PR:L/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