Advisories ยป MGASA-2018-0127

Updated kernel-linus packages fix security vulnerabilities

Publication date: 15 Feb 2018
Type: security
Affected Mageia releases : 6
CVE: CVE-2017-5715 , CVE-2017-5753 , CVE-2017-15129 , CVE-2017-17741 , CVE-2017-1000410


This kernel-linus update is based on the upstream 4.14.18 and and adds some
support for mitigating  Spectre, variant 1 (CVE-2017-5753) and as it is
built with the retpoline-aware gcc-5.5.0-1.mga6, it now provides full
retpoline mitigation for Spectre, variant 2 (CVE-2017-5715).

The BPF interpreter has been used as part of the spectre 2 attack
CVE-2017-5715. To make attacker job harder introduce BPF_JIT_ALWAYS_ON
config option that removes interpreter from the kernel in favor of JIT-only
mode. This is now enabled by default in Mageia kernels.

Other security fixes in this update:

Linux kernel version 3.3-rc1 and later is affected by a vulnerability lies
in the processing of incoming L2CAP commands - ConfigRequest, and
ConfigResponse messages. This info leak is a result of uninitialized stack
variables that may be returned to an attacker in their uninitialized state.
By manipulating the code flows that precede the handling of these
configuration messages, an attacker can also gain some control over which
data will be held in the uninitialized stack variables. This can allow him
to bypass KASLR, and stack canaries protection - as both pointers and stack
canaries may be leaked in this manner (CVE-2017-1000410).

A use-after-free vulnerability was found in network namespaces code
affecting the Linux kernel before 4.14.11. The function get_net_ns_by_id()
in net/core/net_namespace.c does not check for the net::count value after
it has found a peer network in netns_ids 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).

For other fixes in this update, read the referenced changelogs.