Debian LTS: DLA-2385-1: linux-4.19 security update
Summary
Several vulnerabilities have been discovered in the Linux kernel that
may lead to a privilege escalation, denial of service, or information
leak.
CVE-2019-3874
Kernel buffers allocated by the SCTP network protocol were not
limited by the memory cgroup controller. A local user could
potentially use this to evade container memory limits and to cause
a denial of service (excessive memory use).
CVE-2019-19448, 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-2020-10781
Luca Bruno of Red Hat discovered that the zram control file
/sys/class/zram-control/hot_add was readable by all users. On a
system with zram enabled, a local user could use this to cause a
denial of service (memory exhaustion).
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-2020-14314
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
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.
CVE-2020-14385
A bug was discovered in XFS, which could lead to an extended
attribute (xattr) wrongly being detected as invalid. A local user
with access to an XFS filesystem could use this to cause a denial
of service (filesystem shutdown).
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-2020-16166
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-2020-25212
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-2020-26088
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 9 stretch, these problems have been fixed in version
4.19.146-1~deb9u1. This update additionally fixes Debian bugs
#966846, #966917, and #968567; and includes many more bug fixes from
stable updates 4.19.133-4.19.146 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:
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
