RHEL 7 : kernel (RHSA-2018:2785)
High Nessus Plugin ID 117781
SynopsisThe remote Red Hat host is missing one or more security updates.
DescriptionAn update for kernel is now available for Red Hat Enterprise Linux 7.3
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
Security Fix(es) :
* A flaw named SegmentSmack was found in the way the Linux kernel
handled specially crafted TCP packets. A remote attacker could use
this flaw to trigger time and calculation expensive calls to
tcp_collapse_ofo_queue() and tcp_prune_ofo_queue() functions by
sending specially modified packets within ongoing TCP sessions which
could lead to a CPU saturation and hence a denial of service on the
system. Maintaining the denial of service condition requires
continuous two-way TCP sessions to a reachable open port, thus the
attacks cannot be performed using spoofed IP addresses.
* A flaw named FragmentSmack was found in the way the Linux kernel
handled reassembly of fragmented IPv4 and IPv6 packets. A remote
attacker could use this flaw to trigger time and calculation expensive
fragment reassembly algorithm by sending specially crafted packets
which could lead to a CPU saturation and hence a denial of service on
the system. (CVE-2018-5391)
* kernel: mm: use-after-free in do_get_mempolicy function allows local
DoS or other unspecified impact (CVE-2018-10675)
For more details about the security issue(s), including the impact, a
CVSS score, and other related information, refer to the CVE page(s)
listed in the References section.
Red Hat would like to thank Juha-Matti Tilli (Aalto University -
Department of Communications and Networking and Nokia Bell Labs) for
reporting CVE-2018-5390 and CVE-2018-5391.
Bug Fix(es) :
* On systems running Red Hat Enterprise Linux 7 with Red Hat OpenShift
Container Platform 3.5, a node sometimes got into 'NodeNotReady' state
after a CPU softlockup. Consequently, the node was not available. This
update fixes an irq latency source in memory compaction. As a result,
nodes no longer get into 'NodeNotReady' state under the described
* Previously, the kernel source code was missing support to report the
Speculative Store Bypass Disable (SSBD) vulnerability status on IBM
Power Systems and the little-endian variants of IBM Power Systems. As
a consequence, the
incorrectly reported 'Not affected' on both CPU architectures. This
fix updates the kernel source code to properly report the SSBD status
either as 'Vulnerable' or 'Mitigation: Kernel entry/exit barrier
(TYPE)' where TYPE is one of 'eieio', 'hwsync', 'fallback', or
'unknown'. (BZ# 1612351)
* The hypervisors of Red Hat Enterprise Linux 7 virtual machines (VMs)
in certain circumstances mishandled the microcode update in the
kernel. As a consequence, the VMs sometimes became unresponsive when
booting. This update applies an upstream patch to avoid early
microcode update when running under a hypervisor. As a result, kernel
hangs no longer occur in the described scenario. (BZ#1618388)
SolutionUpdate the affected packages.