Debian 9822 Published by

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



ELA-378-1 linux-4.9 security update

Package linux-4.9
Version 4.9.258-1~deb8u1
Related CVEs CVE-2019-19318 CVE-2019-19813 CVE-2019-19816 CVE-2020-27815 CVE-2020-27825 CVE-2020-28374 CVE-2020-29568 CVE-2020-29569 CVE-2020-29660 CVE-2020-29661 CVE-2020-36158 CVE-2021-3178 CVE-2021-3347 CVE-2021-26930 CVE-2021-26931 CVE-2021-26932 CVE-2021-27363 CVE-2021-27364 CVE-2021-27365 CVE-2021-28038

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

CVE-2019-19318, CVE-2019-19813, CVE-2019-19816

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

CVE-2020-27815

A flaw was reported in the JFS filesystem code allowing a local
attacker with the ability to set extended attributes to cause a
denial of service.

CVE-2020-27825

Adam 'pi3' Zabrocki reported a use-after-free flaw in the ftrace
ring buffer resizing logic due to a race condition, which could
result in denial of service or information leak.

CVE-2020-28374

David Disseldorp discovered that the LIO SCSI target implementation
performed insufficient checking in certain XCOPY requests. An
attacker with access to a LUN and knowledge of Unit Serial Number
assignments can take advantage of this flaw to read and write to any
LIO backstore, regardless of the SCSI transport settings.

CVE-2020-29568 (XSA-349)

Michael Kurth and Pawel Wieczorkiewicz reported that frontends can
trigger OOM in backends by updating a watched path.

CVE-2020-29569 (XSA-350)

Olivier Benjamin and Pawel Wieczorkiewicz reported a use-after-free
flaw which can be triggered by a block frontend in Linux blkback. A
misbehaving guest can trigger a dom0 crash by continuously
connecting / disconnecting a block frontend.

CVE-2020-29660

Jann Horn reported a locking inconsistency issue in the tty
subsystem which may allow a local attacker to mount a
read-after-free attack against TIOCGSID.

CVE-2020-29661

Jann Horn reported a locking issue in the tty subsystem which can
result in a use-after-free. A local attacker can take advantage of
this flaw for memory corruption or privilege escalation.

CVE-2020-36158

A buffer overflow flaw was discovered in the mwifiex WiFi driver
which could result in denial of service or the execution of
arbitrary code via a long SSID value.

CVE-2021-3178

吴异 reported an information leak in the NFSv3 server. When only
a subdirectory of a filesystem volume is exported, an NFS client
listing the exported directory would obtain a file handle to the
parent directory, allowing it to access files that were not meant
to be exported.

Even after this update, it is still possible for NFSv3 clients to
guess valid file handles and access files outside an exported
subdirectory, unless the "subtree_check" export option is enabled.
It is recommended that you do not use that option but only export
whole filesystem volumes.

CVE-2021-3347

It was discovered that PI futexes have a kernel stack use-after-free
during fault handling. An unprivileged user could use this flaw to
crash the kernel (resulting in denial of service) or for privilege
escalation.

CVE-2021-26930 (XSA-365)

Olivier Benjamin, Norbert Manthey, Martin Mazein, and Jan
H. Schönherr discovered that the Xen block backend driver
(xen-blkback) did not handle grant mapping errors correctly. A
malicious guest could exploit this bug to cause a denial of
service (crash), or possibly an information leak or privilege
escalation, within the domain running the backend, which is
typically dom0.

CVE-2021-26931 (XSA-362), CVE-2021-26932 (XSA-361), CVE-2021-28038 (XSA-367)

Jan Beulich discovered that the Xen support code and various Xen
backend drivers did not handle grant mapping errors correctly. A
malicious guest could exploit these bugs to cause a denial of
service (crash) within the domain running the backend, which is
typically dom0.

CVE-2021-27363

Adam Nichols reported that the iSCSI initiator subsystem did not
properly restrict access to transport handle attributes in sysfs.
On a system acting as an iSCSI initiator, this is an information
leak to local users and makes it easier to exploit CVE-2021-27364.

CVE-2021-27364

Adam Nichols reported that the iSCSI initiator subsystem did not
properly restrict access to its netlink management interface. On
a system acting as an iSCSI initiator, a local user could use
these to cause a denial of service (disconnection of storage) or
possibly for privilege escalation.

CVE-2021-27365

Adam Nichols reported that the iSCSI initiator subsystem did not
correctly limit the lengths of parameters or "passthrough PDUs"
sent through its netlink management interface. On a system acting
as an iSCSI initiator, a local user could use these to leak the
contents of kernel memory, to cause a denial of service (kernel
memory corruption or crash), and probably for privilege
escalation.
For Debian 8 jessie, these problems have been fixed in version 4.9.258-1~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/

  ELA-378-1 linux-4.9 security update