MGASA-2018-0077

This kernel-tmb update is based on the upstream 4.14.13 and and fixes several security issues.

The most important fix in this update is for the security issue named "Meltdown" that is fixed in theese kernels by enabling kernel Page Table Isolation (KTPI). Note that according to AMD, this issue does not effect Amd processors, so it is not enabled by default on systems using Amd CPU.

The list of known security fixes and mitigations in this kernel:

kvm: vmx: Scrub hardware GPRs at VM-exit. This enables partial mitigation in kvm for the security issue named "Spectre" (CVE-2017-5715, CVE-2017-5753).

Systems with microprocessors utilizing speculative execution and indirect branch prediction may allow unauthorized disclosure of information to an attacker with local user access via a side-channel analysis of the data cache (CVE-2017-5754, "Meltdown").

A use-after-free vulnerability was found in network namespaces code affecting the Linux kernel before 4.14.11. The function getnetnsbyid() in net/core/netnamespace.c does not check for the net::count value after it has found a peer network in netnsids idr, which could lead to double free and memory corruption. This vulnerability could allow an unprivileged local user to induce kernel memory corruption on the system, leading to a crash. Due to the nature of the flaw, privilege escalation cannot be fully ruled out, although it is thought to be unlikely (CVE-2017-15129).

The KVM implementation in the Linux kernel through 4.14.7 allows attackers to obtain potentially sensitive information from kernel memory, aka a write_mmio stack-based out-of-bounds read, related to arch/x86/kvm/x86.c and include/trace/events/kvm.h (CVE-2017-17741).

The kernels are also fixed to allow loading cpu microcode for Amd family 17 (Zen) processors.

For more info about Meltdown, Spectre and other fixes in this update, see the refences.