Debian 9988 Published by

A linux-4.9 security update has been released for Debian GNU/Linux 8 Extended LTS to address several vulnerabilities.



ELA-458-1 linux-4.9 security update

Package linux-4.9
Version 4.9.272-1~deb8u2
Related CVEs CVE-2020-24586 CVE-2020-24587 CVE-2020-24588 CVE-2020-25670 CVE-2020-25671 CVE-2020-25672 CVE-2020-26139 CVE-2020-26147 CVE-2020-26558 CVE-2020-29374 CVE-2020-36322 CVE-2021-0129 CVE-2021-0512 CVE-2021-3428 CVE-2021-3483 CVE-2021-3564 CVE-2021-3573 CVE-2021-3587 CVE-2021-20292 CVE-2021-23133 CVE-2021-23134 CVE-2021-28660 CVE-2021-28688 CVE-2021-28950 CVE-2021-28964 CVE-2021-28971 CVE-2021-29154 CVE-2021-29265 CVE-2021-29647 CVE-2021-29650 CVE-2021-30002 CVE-2021-31916 CVE-2021-32399 CVE-2021-33034

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.

This update is not yet available for the armel (ARM EABI soft-float) architecture.

CVE-2020-24586, CVE-2020-24587, CVE-2020-26147

Mathy Vanhoef discovered that many Wi-Fi implementations,
including Linux's mac80211, did not correctly implement reassembly
of fragmented packets. In some circumstances, an attacker within
range of a network could exploit these flaws to forge arbitrary
packets and/or to access sensitive data on that network.
CVE-2020-24588

Mathy Vanhoef discovered that most Wi-Fi implementations,
including Linux's mac80211, did not authenticate the "is
aggregated" packet header flag. An attacker within range of a
network could exploit this to forge arbitrary packets on that
network.
CVE-2020-25670, CVE-2020-25671, CVE-2021-23134

kiyin (尹亮) of TenCent discovered several reference counting bugs
in the NFC LLCP implementation which could lead to use-after-free.
A local user could exploit these for denial of service (crash or
memory corruption) or possibly for privilege escalation.

Nadav Markus and Or Cohen of Palo Alto Networks discovered that
the original fixes for these introduced a new bug that could
result in use-after-free and double-free. This has also been
fixed.
CVE-2020-25672

kiyin (尹亮) of TenCent discovered a memory leak in the NFC LLCP
implementation. A local user could exploit this for denial of
service (memory exhaustion).
CVE-2020-26139

Mathy Vanhoef discovered that a bug in some Wi-Fi implementations,
including Linux's mac80211. When operating in AP mode, they would
forward EAPOL frames from one client to another while the sender
was not yet authenticated. An attacker within range of a network
could use this for denial of service or as an aid to exploiting
other vulnerabilities.
CVE-2020-26558, CVE-2021-0129

Researchers at ANSSI discovered vulnerabilities in the Bluetooth
Passkey authentication method, and in Linux's implementation of
it. An attacker within range of two Bluetooth devices while they
pair using Passkey authentication could exploit this to obtain the
shared secret (Passkey) and then impersonate either of the devices
to each other.
CVE-2020-29374

Jann Horn of Google reported a flaw in Linux's virtual memory
management. A parent and child process initially share all their
memory, but when either writes to a shared page, the page is
duplicated and unshared (copy-on-write). However, in case an
operation such as vmsplice() required the kernel to take an
additional reference to a shared page, and a copy-on-write occurs
during this operation, the kernel might have accessed the wrong
process's memory. For some programs, this could lead to an
information leak or data corruption.
CVE-2020-36322, CVE-2021-28950

The syzbot tool found that the FUSE (filesystem-in-user-space)
implementation did not correctly handle a FUSE server returning
invalid attributes for a file. A local user permitted to run a
FUSE server could use this to cause a denial of service (crash).

The original fix for this introduced a different potential denial
of service (infinite loop in kernel space), which has also been
fixed.
CVE-2021-3428

Wolfgang Frisch reported a potential integer overflow in the ext4
filesystem driver. A user permitted to mount arbitrary filesystem
images could use this to cause a denial of service (crash).
CVE-2021-3483

马哲宇 (Zheyu Ma) reported a bug in the "nosy" driver for TI
PCILynx FireWire controllers, which could lead to list corruption
and a use-after-free. On a system that uses this driver, local
users granted access to /dev/nosy could exploit this to cause a
denial of service (crash or memory corruption) or possibly for
privilege escalation.
CVE-2021-3564, CVE-2021-3573, CVE-2021-32399

The BlockSec team discovered several race conditions in the
Bluetooth subsystem that could lead to a use-after-free or
double-free. A local user could exploit these to caue a denial of
service (crash or memory corruption) or possibly for privilege
escalation.
CVE-2021-3587

Active Defense Lab of Venustech discovered a potential null
pointer dereference in the NFC LLCP implementation. A local user
could use this to cause a denial of service (crash).
CVE-2021-20292

It was discovered that the TTM buffer allocation API used by GPU
drivers did not handle allocation failures in the way that most
drivers expected, resulting in a double-free on failure. A local
user on a system using one of these drivers could possibly exploit
this to cause a denial of service (crash or memory corruption) or
for privilege escalation. The API has been changed to match
driver expectations.
CVE-2021-23133

Or Cohen of Palo Alto Networks discovered a race condition in the
SCTP implementation, which can lead to list corruption. A local
user could exploit this to cause a denial of service (crash or
memory corruption) or possibly for privilege escalation.
CVE-2021-28660

It was discovered that the rtl8188eu WiFi driver did not correctly
limit the length of SSIDs copied into scan results. An attacker
within WiFi range could use this to cause a denial of service
(crash or memory corruption) or possibly to execute code on a
vulnerable system.
CVE-2021-28688 (XSA-371)

It was discovered that the original fix for CVE-2021-26930
(XSA-365) introduced a potential resource leak. A malicious guest
could presumably exploit this to cause a denial of service
(resource exhaustion) within the host.
CVE-2021-28964

Zygo Blaxell reported a race condition in the Btrfs driver which
can lead to an assertion failure. On systems using Btrfs, a local
user could exploit this to cause a denial of service (crash).
CVE-2021-28971

Vince Weaver reported a bug in the performance event handler for
Intel PEBS. A workaround for a hardware bug on Intel CPUs
codenamed "Haswell" and earlier could lead to a null pointer
dereference. On systems with the affected CPUs, if users are
permitted to access performance events, a local user may exploit
this to cause a denial of service (crash).

By default, unprivileged users do not have access to performance
events, which mitigates this issue. This is controlled by the
kernel.perf_event_paranoid sysctl.
CVE-2021-29154

It was discovered that the Extended BPF (eBPF) JIT compiler
for x86_64 generated incorrect branch instructions in some
cases. On systems where eBPF JIT is enabled, users could
exploit this to execute arbitrary code in the kernel.

By default, eBPF JIT is disabled, mitigating this issue. This is
controlled by the net.core.bpf_jit_enable sysctl.
CVE-2021-29265

The syzbot tool found a race condition in the USB/IP host
(server) implementation which can lead to a null pointer
dereference. On a system acting as a USB/IP host, a client
can exploit this to cause a denial of service (crash).
CVE-2021-29647

The syzbot tool found an information leak in the Qualcomm IPC
Router (qrtr) implementation.

This protocol is not enabled in Debian's official kernel
configurations.
CVE-2021-29650

It was discovered that a data race in the netfilter subsystem
could lead to a null pointer dereference during replacement of a
table. A local user with CAP_NET_ADMIN capability in any user
namespace could use this to cause a denial of service (crash).

By default, unprivileged users cannot create user namespaces,
which mitigates this issue. This is controlled by the
kernel.unprivileged_userns_clone sysctl.
CVE-2021-30002

Arnd Bergmann and the syzbot tool found a memory leak in the
Video4Linux (v4l) subsystem. A local user permitted to access
video devices (by default, any member of the "video" group) could
exploit this to cause a denial of service (memory exhaustion).
CVE-2021-31916

Dan Carpenter reported incorrect parameter validation in the
device-mapper (dm) subsystem, which could lead to a heap buffer
overrun. However, only users with CAP_SYS_ADMIN capability
(i.e. root-equivalent) could trigger this bug, so it did not
have any security impact in this kernel version.
CVE-2021-33034

The syzbot tool found a bug in the Bluetooth subsystem that could
lead to a use-after-free. A local user could use this to cause a
denial of service (crash or memory corruption) or possibly for
privilege escalation.
For Debian 8 jessie, these problems have been fixed in version 4.9.272-1~deb8u2.

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/

  ELA-458-1 linux-4.9 security update