Important kernel security update: CVE-2017-8797 and other; Virtuozzo ReadyKernel patch 25.0 for Virtuozzo 7.0.4 and 7.0.4 HF3

Issue date: 2017-07-05

Applies to: Virtuozzo 7.0

Virtuozzo Advisory ID: VZA-2017-063

1. Overview

The cumulative Virtuozzo ReadyKernel patch was updated with security 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] The NFSv4 server in the Linux kernel compiled with CONFIG_NFSD_PNFS enabled does not properly validate layout type when processing NFSv4 pNFS LAYOUTGET and GETDEVICEINFO operands. The attack payload fits to single one-way UDP packet. The provided input value is used for array dereferencing. This may lead to a remote DoS of [knfsd] and so to a soft-lockup of a whole system. (CVE-2017-8797)

  • [Important] A flaw was found in the way Linux kernel allocates heap memory to build the scattergather list from a fragment list(skb_shinfo(skb)->frag_list) in the socket buffer(skb_buff). The heap overflow occurred if ‘MAX_SKB_FRAGS + 1’ parameter and ‘NETIF_F_FRAGLIST’ feature are both used together. A remote user or process could use this flaw to potentially escalate their privilege on a system. (CVE-2017-7477)

  • [Moderate] A vulnerability was found in the implementation of setsockopt() operations in the Linux kernel. A privileged user inside a container could cause a DoS attack on the host (kernel deadlock in ip_ra_control() function) using a specially crafted sequence of system calls. (PSBM-64752)

3. Installing the Update

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