ELA-307-1 linux-4.9 security update

Linux Kernel update

2020-11-03
Packagelinux-4.9
Version4.9.240-2~deb8u1
Related CVEs CVE-2019-9445 CVE-2019-19073 CVE-2019-19074 CVE-2019-19448 CVE-2020-12351 CVE-2020-12352 CVE-2020-12655 CVE-2020-12771 CVE-2020-12888 CVE-2020-14305 CVE-2020-14314 CVE-2020-14331 CVE-2020-14356 CVE-2020-14386 CVE-2020-14390 CVE-2020-15393 CVE-2020-16166 CVE-2020-24490 CVE-2020-25211 CVE-2020-25212 CVE-2020-25220 CVE-2020-25284 CVE-2020-25285 CVE-2020-25641 CVE-2020-25643 CVE-2020-26088

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

CVE-2019-9445

A potential out-of-bounds read was discovered in the F2FS
implementation.  A user permitted to mount and access arbitrary
filesystems could potentially use this to cause a denial of
service (crash) or to read sensitive information.

CVE-2019-19073, CVE-2019-19074

Navid Emamdoost discovered potential memory leaks in the ath9k and
ath9k_htc drivers.  The security impact of these is unclear.

CVE-2019-19448

"Team bobfuzzer" reported a bug in Btrfs that could lead to a
use-after-free, and could be triggered by crafted filesystem
images.  A user permitted to mount and access arbitrary
filesystems could use this to cause a denial of service (crash or
memory corruption) or possibly for privilege escalation.

CVE-2020-12351

Andy Nguyen discovered a flaw in the Bluetooth implementation in
the way L2CAP packets with A2MP CID are handled.  A remote attacker
within a short distance, knowing the victim's Bluetooth device
address, can send a malicious l2cap packet and cause a denial of
service or possibly arbitrary code execution with kernel
privileges.

CVE-2020-12352

Andy Nguyen discovered a flaw in the Bluetooth implementation.
Stack memory is not properly initialised when handling certain AMP
packets.  A remote attacker within a short distance, knowing the
victim's Bluetooth device address address, can retrieve kernel
stack information.

CVE-2020-12655

Zheng Bin reported that crafted XFS volumes could trigger a system
hang.  An attacker able to mount such a volume could use this to
cause a denial of service.

CVE-2020-12771

Zhiqiang Liu reported a bug in the bcache block driver that could
lead to a system hang.  The security impact of this is unclear.

CVE-2020-12888

It was discovered that the PCIe Virtual Function I/O (vfio-pci)
driver allowed users to disable a device's memory space while it
was still mapped into a process.  On some hardware platforms,
local users or guest virtual machines permitted to access PCIe
Virtual Functions could use this to cause a denial of service
(hardware error and crash).

CVE-2020-14305

Vasily Averin of Virtuozzo discovered a potential heap buffer
overflow in the netfilter nf_contrack_h323 module.  When this
module is used to perform connection tracking for TCP/IPv6, a
remote attacker could use this to cause a denial of service (crash
or memory corruption) or possibly for remote code execution with
kernel privilege.

CVE-2020-14314

A bug was discovered in the ext4 filesystem that could lead to an
out-of-bound read.  A local user permitted to mount and access
arbitrary filesystem images could use this to cause a denial of
service (crash).

CVE-2020-14331

A bug was discovered in the VGA console driver's soft-scrollback
feature that could lead to a heap buffer overflow.  On a system
with a custom kernel that has CONFIG_VGACON_SOFT_SCROLLBACK
enabled, a local user with access to a console could use this to
cause a denial of service (crash or memory corruption) or possibly
for privilege escalation.

CVE-2020-14356, CVE-2020-25220

A bug was discovered in the cgroup subsystem's handling of socket
references to cgroups.  In some cgroup configurations, this could
lead to a use-after-free.  A local user might be able to use this
to cause a denial of service (crash or memory corruption) or
possibly for privilege escalation.

The original fix for this bug introudced a new security issue,
which is also addressed in this update.

CVE-2020-14386

Or Cohen discovered a bug in the packet socket (AF_PACKET)
implementation which could lead to a heap buffer overflow.  A
local user with the CAP_NET_RAW capability (in any user namespace)
could use this to cause a denial of service (crash or memory
corruption) or possibly for privilege escalation.

CVE-2020-14390

Minh Yuan discovered a bug in the framebuffer console driver's
scrollback feature that could lead to a heap buffer overflow.  On
a system using framebuffer consoles, a local user with access to a
console could use this to cause a denial of service (crash or
memory corruption) or possibly for privilege escalation.

The scrollback feature has been disabled for now, as no other fix
was available for this issue.

CVE-2020-15393

Kyungtae Kim reported a memory leak in the usbtest driver.  The
security impact of this is unclear.

CVE-2020-16166

Amit Klein reported that the random number generator used by the
network stack might not be re-seeded for long periods of time,
making e.g. client port number allocations more predictable.  This
made it easier for remote attackers to carry out some network-
based attacks such as DNS cache poisoning or device tracking.

CVE-2020-24490

Andy Nguyen discovered a flaw in the Bluetooth implementation that
can lead to a heap buffer overflow.  On systems with a Bluetooth 5
hardware interface, a remote attacker within a short distance can
use this to cause a denial of service (crash or memory corruption)
or possibly for remote code execution with kernel privilege.

CVE-2020-25211

A flaw was discovered in netfilter subsystem.  A local attacker
able to inject conntrack Netlink configuration can cause a denial
of service.

CVE-2020-25212

A bug was discovered in the NFSv4 client implementation that could
lead to a heap buffer overflow.  A malicious NFS server could use
this to cause a denial of service (crash or memory corruption) or
possibly to execute arbitrary code on the client.

CVE-2020-25284

It was discovered that the Rados block device (rbd) driver allowed
tasks running as uid 0 to add and remove rbd devices, even if they
dropped capabilities.  On a system with the rbd driver loaded,
this might allow privilege escalation from a container with a task
running as root.

CVE-2020-25285

A race condition was discovered in the hugetlb filesystem's sysctl
handlers, that could lead to stack corruption.  A local user
permitted to write to hugepages sysctls could use this to cause a
denial of service (crash or memory corruption) or possibly for
privilege escalation.  By default only the root user can do this.

CVE-2020-25641

The syzbot tool found a bug in the block layer that could lead to
an infinite loop.  A local user with access to a raw block device
could use this to cause a denial of service (unbounded CPU use and
possible system hang).

CVE-2020-25643

ChenNan Of Chaitin Security Research Lab discovered a flaw in the
hdlc_ppp module.  Improper input validation in the ppp_cp_parse_cr()
function may lead to memory corruption and information disclosure.

CVE-2020-26088

It was discovered that the NFC (Near Field Communication) socket
implementation allowed any user to create raw sockets.  On a
system with an NFC interface, this allowed local users to evade
local network security policy.

For Debian 8 jessie, these problems have been fixed in version 4.9.240-2~deb8u1.

We recommend that you upgrade your linux-4.9 packages.

Further information about Extended LTS security advisories can be found at: https://deb.freexian.com/extended-lts/