Important kernel security update: CVE-2017-8824 and other; Virtuozzo ReadyKernel patch 39.2 for Virtuozzo 7.0.4 and 7.0.4 HF3

Issue date: 2017-12-11

Applies to: Virtuozzo 7.0

Virtuozzo Advisory ID: VZA-2017-109

1. Overview

The cumulative Virtuozzo ReadyKernel patch was updated with security and stability fixes. The patch applies to Virtuozzo kernels 3.10.0-514.16.1.vz7.30.10 (Virtuozzo 7.0.4) and 3.10.0-514.16.1.vz7.30.15 (Virtuozzo 7.0.4 HF3)

2. Security Fixes

[Important] dccp_disconnect() set the socket state to DCCP_CLOSED but did not properly free some of the resources associated with that socket. This could result in a use-after-free and could potentially allow an attacker to escalate their privileges. (CVE-2017-8824)
[Important] The Linux kernel is vulnerable to a use-after-free issue. It could occur while closing a xfrm netlink socket, in xfrm_dump_policy_done. A user/process could use this flaw to potentially escalate their privileges on a system. (CVE-2017-16939)
[Important] A flaw was found in the patches used to fix the ‘Dirty COW’ vulnerability (CVE-2016-5195). An attacker, able to run local code, can exploit a race condition in transparent huge pages to modify usually read-only huge pages. (CVE-2017-1000405)

3. Bug Fixes

memcgroup: potential deadlocks and soft lockups. (PSBM-76011)
Many of the issues that BUG_ON()s were supposed to catch in tcache were not serious enough to crash the kernel. A warning will now be output in such cases instead. (PSBM-77154)

4. Installing the Update

Download, install, and instantly apply the patch to the current kernel by running ‘readykernel update’.

5. References

The JSON file with the list of new and updated packages is available at JSON file.