Debian Security Advisory

DLA-2420-1 linux -- LTS security update

Date Reported:

30 Oct 2020

Affected Packages:

Vulnerable:

Yes

Security database references:

In Mitre's CVE dictionary: 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.

More information:

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 9 stretch, these problems have been fixed in version 4.9.240-1. This update additionally includes many more bug fixes from stable updates 4.9.229-4.9.240 inclusive.

We recommend that you upgrade your linux packages.

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

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