ELA-133-1 linux security update

Linux kernel update

Related CVEs CVE-2019-3846 CVE-2019-5489 CVE-2019-10126 CVE-2019-11477 CVE-2019-11478 CVE-2019-11479 CVE-2019-11810 CVE-2019-11833 CVE-2019-11884

Several vulnerabilities have been discovered in the Linux kernel that may lead to a privilege escalation, denial of service or information leaks.

CVE-2019-3846, CVE-2019-10126

huangwen reported multiple buffer overflows in the Marvell wifi
(mwifiex) driver, which a local user could use to cause denial of
service or the execution of arbitrary code.


Daniel Gruss, Erik Kraft, Trishita Tiwari, Michael Schwarz, Ari
Trachtenberg, Jason Hennessey, Alex Ionescu, and Anders Fogh
discovered that local users could use the mincore() system call to
obtain sensitive information from other processes that access the
same memory-mapped file.


Jonathan Looney reported that a specially crafted sequence of TCP
selective acknowledgements (SACKs) allows a remotely triggerable
kernel panic.


Jonathan Looney reported that a specially crafted sequence of TCP
selective acknowledgements (SACKs) will fragment the TCP
retransmission queue, allowing an attacker to cause excessive
resource usage.


Jonathan Looney reported that an attacker could force the Linux
kernel to segment its responses into multiple TCP segments, each of
which contains only 8 bytes of data, drastically increasing the
bandwidth required to deliver the same amount of data.

This update introduces a new sysctl value to control the minimal MSS
(net.ipv4.tcp_min_snd_mss), which by default uses the formerly hard-
coded value of 48.  We recommend raising this to 512 unless you know
that your network requires a lower value.  (This value applies to
Linux 3.16 only.)


It was discovered that the megaraid_sas driver did not correctly
handle a failed memory allocation during initialisation, which
could lead to a double-free.  This might have some security
impact, but it cannot be triggered by an unprivileged user.


It was discovered that the ext4 filesystem implementation writes
uninitialised data from kernel memory to new extent blocks.  A
local user able to write to an ext4 filesystem and then read the
filesystem image, for example using a removable drive, might be
able to use this to obtain sensitive information.


It was discovered that the Bluetooth HIDP implementation did not
ensure that new connection names were null-terminated.  A local
user with CAP_NET_ADMIN capability might be able to use this to
obtain sensitive information from the kernel stack.

For Debian 7 Wheezy, these problems have been fixed in version 3.16.68-2~deb7u1.

We recommend that you upgrade your linux packages.

Further information about Extended LTS security advisories can be found in the dedicated section of our website.