RHEL 7 : kernel (RHSA-2017:1766)

critical Nessus Plugin ID 101799
New! Plugin Severity Now Using CVSS v3

The calculated severity for Plugins has been updated to use CVSS v3 by default. Plugins that do not have a CVSS v3 score will fall back to CVSS v2 for calculating severity. Severity display preferences can be toggled in the settings dropdown.

Synopsis

The remote Red Hat host is missing one or more security updates.

Description

An update for kernel is now available for Red Hat Enterprise Linux 7.2 Extended Update Support.

Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

The kernel packages contain the Linux kernel, the core of any Linux operating system.

Security Fix(es) :

* The NFSv2 and NFSv3 server implementations in the Linux kernel through 4.10.13 lacked certain checks for the end of a buffer. A remote attacker could trigger a pointer-arithmetic error or possibly cause other unspecified impacts using crafted requests related to fs/nfsd/nfs3xdr.c and fs/nfsd/nfsxdr.c. (CVE-2017-7895, Important)

Red Hat would like to thank Ari Kauppi for reporting this issue.

Bug Fix(es) :

* Previously, a race condition between Linux kernel module error handling and kprobe registration code existed in the Linux kernel. The protection that was applied during module error handling code could be overridden by kprobe registration code before the module was deallocated. Consequently, the mapped page could be freed and become not 'writable'. When this page was later accessed, a page fault occurred, which led to a kernel panic. This update fixes the race condition, and the kernel no longer panics due to this bug.
(BZ#1454683)

* Due to a race with another NFS mount, the nfs41_walk_client_list() function previously established a lease on the nfs_client pointer before the check for trunking was finished. This update ensures the processes follow the correct order and the race no longer occurs in this scenario. (BZ#1447383)

* If a duplicate IPv6 address or an issue setting an address was present in the net/ipv6/addrconf.c file, a race condition occurred that could cause an IFP refcount leak. Attempts to unregister a netdevice then produced 'Unregister Netdevice Failed' error messages.
The provided patch fixes this bug, and race conditions no longer occur in this situation. (BZ#1449103)

* Previously, subtracting from vCPU threads could cause a steal_time overflow on QEMU live migration. This update makes sure steal_time accumulation to vCPU entry time is moved before copying steal_time data to QEMU guest, thus fixing this bug. (BZ#1274919)

Solution

Update the affected packages.

See Also

https://access.redhat.com/errata/RHSA-2017:1766

https://access.redhat.com/security/cve/cve-2017-7895

Plugin Details

Severity: Critical

ID: 101799

File Name: redhat-RHSA-2017-1766.nasl

Version: 3.12

Type: local

Agent: unix

Published: 7/19/2017

Updated: 10/24/2019

Dependencies: ssh_get_info.nasl, linux_alt_patch_detect.nasl

Risk Information

VPR

Risk Factor: Medium

Score: 5.9

CVSS v2

Risk Factor: Critical

Base Score: 10

Temporal Score: 7.4

Vector: AV:N/AC:L/Au:N/C:C/I:C/A:C

Temporal Vector: E:U/RL:OF/RC:C

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: E:U/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:redhat:enterprise_linux:kernel, p-cpe:/a:redhat:enterprise_linux:kernel-abi-whitelists, p-cpe:/a:redhat:enterprise_linux:kernel-debug, p-cpe:/a:redhat:enterprise_linux:kernel-debug-debuginfo, p-cpe:/a:redhat:enterprise_linux:kernel-debug-devel, p-cpe:/a:redhat:enterprise_linux:kernel-debuginfo, p-cpe:/a:redhat:enterprise_linux:kernel-debuginfo-common-s390x, p-cpe:/a:redhat:enterprise_linux:kernel-debuginfo-common-x86_64, p-cpe:/a:redhat:enterprise_linux:kernel-devel, p-cpe:/a:redhat:enterprise_linux:kernel-doc, p-cpe:/a:redhat:enterprise_linux:kernel-headers, p-cpe:/a:redhat:enterprise_linux:kernel-kdump, p-cpe:/a:redhat:enterprise_linux:kernel-kdump-debuginfo, p-cpe:/a:redhat:enterprise_linux:kernel-kdump-devel, p-cpe:/a:redhat:enterprise_linux:kernel-tools, p-cpe:/a:redhat:enterprise_linux:kernel-tools-debuginfo, p-cpe:/a:redhat:enterprise_linux:kernel-tools-libs, p-cpe:/a:redhat:enterprise_linux:kernel-tools-libs-devel, p-cpe:/a:redhat:enterprise_linux:perf, p-cpe:/a:redhat:enterprise_linux:perf-debuginfo, p-cpe:/a:redhat:enterprise_linux:python-perf, p-cpe:/a:redhat:enterprise_linux:python-perf-debuginfo, cpe:/o:redhat:enterprise_linux:7.2

Required KB Items: Host/local_checks_enabled, Host/RedHat/release, Host/RedHat/rpm-list, Host/cpu

Exploit Ease: No known exploits are available

Patch Publication Date: 7/18/2017

Vulnerability Publication Date: 4/28/2017

Reference Information

CVE: CVE-2017-7895

RHSA: 2017:1766