Important kernel security update: CVE-2018-3620 and other issues; new kernel 3.10.0-862.11.6.vz7.64.7; Virtuozzo 7.0 Update 8 Hotfix 1 (7.0.8-507)

This update provides a new kernel for Virtuozzo 7.0 that is a rebase to the Red Hat Enterprise Linux 7.5 kernel 3.10.0-862.11.6.el7. The new kernel inherits a number of security fixes from the RHEL kernel and introduces internal stability fixes.
Vulnerability id: CVE-2017-13215
A flaw was found in the Linux kernel’s skcipher component, which affects the skcipher_recvmsg function. Attackers using a specific input can lead to a privilege escalation.

Vulnerability id: CVE-2018-3620, CVE-2018-3646
Modern operating systems implement virtualization of physical memory to efficiently use available system resources and provide inter-domain protection through access control and isolation. The L1TF issue was found in the way the x86 microprocessor designs have implemented speculative execution of instructions (a commonly used performance optimisation) in combination with handling of page-faults caused by terminated virtual to physical address resolving process. As a result, an unprivileged attacker could use this flaw to read privileged memory of the kernel or other processes and/or cross guest/host boundaries to read host memory by conducting targeted cache side-channel attacks.

Vulnerability id: CVE-2018-3693
An industry-wide issue was found in the way many modern microprocessor designs have implemented speculative execution of instructions past bounds check. The flaw relies on the presence of a precisely-defined instruction sequence in the privileged code and the fact that memory writes occur to an address which depends on the untrusted value. Such writes cause an update into the microprocessor’s data cache even for speculatively executed instructions that never actually commit (retire). As a result, an unprivileged attacker could use this flaw to influence speculative execution and/or read privileged memory by conducting targeted cache side-channel attacks.

Vulnerability id: CVE-2018-5390
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.

Vulnerability id: CVE-2018-7566
ALSA sequencer core initializes the event pool on demand by invoking snd_seq_pool_init() when the first write happens and the pool is empty. A user can reset the pool size manually via ioctl concurrently, and this may lead to UAF or out-of-bound access.

Vulnerability id: CVE-2018-10675
The do_get_mempolicy() function in mm/mempolicy.c in the Linux kernel allows local users to hit a use-after-free bug via crafted system calls and thus cause a denial of service (DoS) or possibly have unspecified other impact. Due to the nature of the flaw, privilege escalation cannot be fully ruled out.