Important kernel security update: CVE-2017-8824 and other; Virtuozzo ReadyKernel patch 42.0 for Virtuozzo 7.0.0, 7.0.1, and 7.0.3

Issue date: 2018-01-12

Applies to: Virtuozzo 7.0

Virtuozzo Advisory ID: VZA-2018-004

1. Overview

The cumulative Virtuozzo ReadyKernel patch was updated with security and stability fixes. The patch applies to Virtuozzo kernels 3.10.0-327.18.2.vz7.15.2 (Virtuozzo 7.0.0), 3.10.0-327.42.0.vz7.18.7 (Virtuozzo 7.0.1), and 3.10.0-327.42.0.vz7.20.18 (Virtuozzo 7.0.3).

2. Security Fixes

[Important] A vulnerability was found in DCCP socket handling code. 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)
[Moderate] The function get_net_ns_by_id() does not check the net.count value when processing a peer network, which could lead to double free and memory corruption. An unprivileged local user could use this vulnerability to crash the system. (CVE-2017-15129)
[Moderate] If the system uses iptables and there are iptables rules with TCPMSS action there, a remote attacker could cause a denial of service (use-after-free in tcpmss_mangle_packet function leading to memory corruption) or possibly have unspecified other impact by sending specially crafted network packets. (CVE-2017-18017)
[Moderate] A flaw was found in the patches used to fix the ‘Dirty COW’ vulnerability (CVE-2016-5195). An attacker, able to run local code, could 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)
The kernel could consider a container stopped before the resources of that container, for example, VEIP addresses, have been released. As a result, the system could fail to restart the container. (PSBM-78078)
Migrating large memory ranges could take a while. With no resched points available, it caused soft lockups in isolate_lru_page(). (PSBM-79273)
Kernel warnings about memory allocation failures in vznetstat. (PSBM-79502)

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.