Debian 9988 Published by

A linux-4.19 security update has been released for Debian GNU/Linux 9 LTS to address several vulnerabilities that may lead to the execution of arbitrary code, privilege escalation, denial of service, or information leaks.



DLA 2690-1: linux-4.19 security update


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Debian LTS Advisory DLA-2690-1 debian-lts@lists.debian.org
  https://www.debian.org/lts/security/ Ben Hutchings
June 22, 2021   https://wiki.debian.org/LTS
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Package : linux-4.19
Version : 4.19.194-1~deb9u1
CVE ID : 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-2021-0129 CVE-2021-3483
CVE-2021-3506 CVE-2021-3564 CVE-2021-3573 CVE-2021-3587
CVE-2021-23133 CVE-2021-23134 CVE-2021-28688 CVE-2021-28964
CVE-2021-28971 CVE-2021-29154 CVE-2021-29155 CVE-2021-29264
CVE-2021-29647 CVE-2021-29650 CVE-2021-31829 CVE-2021-31916
CVE-2021-32399 CVE-2021-33034
Debian Bug : 986949 988352 989451

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-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-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-2021-3506

The ADLab of venustech discovered a bug in the F2FS driver which
could lead to an out-of-bounds read when accessing a crafted
filesystem. A local user permitted to mount arbitrary filesystems
could exploit this to cause a denial of service (crash) or other
security impact.

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-2021-23133

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-2021-28688 (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-2021-29155, CVE-2021-31829

Piotr Krysiuk and Benedict Schlueter discovered that the Extended
BPF (eBPF) verifier did not completely protect against information
leaks due to speculative execution. A local user could exploit
these to obtain sensitive information from kernel memory.

CVE-2021-29264

It was discovered that the "gianfar" Ethernet driver used with
some Freescale SoCs did not correctly handle a Rx queue overrun
when jumbo packets were enabled. On systems using this driver and
jumbo packets, an attacker on the network could exploit this to
cause a denial of service (crash).

This driver is not enabled in Debian's official kernel
configurations.

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-2021-31916

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 9 stretch, these problems have been fixed in version
4.19.194-1~deb9u1. This update additionally fixes Debian bug
#986949, #988352, and #989451; and includes many more bug fixes from
stable updates 4.19.182-4.19.194 inclusive.

We recommend that you upgrade your linux-4.19 packages.

For the detailed security status of linux-4.19 please refer to
its security tracker page at:
  https://security-tracker.debian.org/tracker/linux-4.19

Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at:   https://wiki.debian.org/LTS

Ben Hutchings - Debian developer, member of kernel, installer and LTS teams