========================================================================== Ubuntu Security Notice USN-4752-1 February 25, 2021 linux-oem-5.6 vulnerabilities ========================================================================== A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 20.04 LTS Summary: Several security issues were fixed in the Linux kernel. Software Description: - linux-oem-5.6: Linux kernel for OEM systems Details: Daniele Antonioli, Nils Ole Tippenhauer, and Kasper Rasmussen discovered that legacy pairing and secure-connections pairing authentication in the Bluetooth protocol could allow an unauthenticated user to complete authentication without pairing credentials via adjacent access. A physically proximate attacker could use this to impersonate a previously paired Bluetooth device. (CVE-2020-10135) Jay Shin discovered that the ext4 file system implementation in the Linux kernel did not properly handle directory access with broken indexing, leading to an out-of-bounds read vulnerability. A local attacker could use this to cause a denial of service (system crash). (CVE-2020-14314) It was discovered that the block layer implementation in the Linux kernel did not properly perform reference counting in some situations, leading to a use-after-free vulnerability. A local attacker could use this to cause a denial of service (system crash). (CVE-2020-15436) It was discovered that the serial port driver in the Linux kernel did not properly initialize a pointer in some situations. A local attacker could possibly use this to cause a denial of service (system crash). (CVE-2020-15437) Andy Nguyen discovered that the Bluetooth HCI event packet parser in the Linux kernel did not properly handle event advertisements of certain sizes, leading to a heap-based buffer overflow. A physically proximate remote attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2020-24490) It was discovered that the NFS client implementation in the Linux kernel did not properly perform bounds checking before copying security labels in some situations. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2020-25212) It was discovered that the Rados block device (rbd) driver in the Linux kernel did not properly perform privilege checks for access to rbd devices in some situations. A local attacker could use this to map or unmap rbd block devices. (CVE-2020-25284) It was discovered that the block layer subsystem in the Linux kernel did not properly handle zero-length requests. A local attacker could use this to cause a denial of service. (CVE-2020-25641) It was discovered that the HDLC PPP implementation in the Linux kernel did not properly validate input in some situations. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2020-25643) Kiyin (尹亮) discovered that the perf subsystem in the Linux kernel did not properly deallocate memory in some situations. A privileged attacker could use this to cause a denial of service (kernel memory exhaustion). (CVE-2020-25704) It was discovered that the KVM hypervisor in the Linux kernel did not properly handle interrupts in certain situations. A local attacker in a guest VM could possibly use this to cause a denial of service (host system crash). (CVE-2020-27152) It was discovered that the jfs file system implementation in the Linux kernel contained an out-of-bounds read vulnerability. A local attacker could use this to possibly cause a denial of service (system crash). (CVE-2020-27815) It was discovered that an information leak existed in the syscall implementation in the Linux kernel on 32 bit systems. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2020-28588) It was discovered that the framebuffer implementation in the Linux kernel did not properly perform range checks in certain situations. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2020-28915) Jann Horn discovered a race condition in the copy-on-write implementation in the Linux kernel when handling hugepages. A local attacker could use this to gain unintended write access to read-only memory pages. (CVE-2020-29368) Jann Horn discovered that the mmap implementation in the Linux kernel contained a race condition when handling munmap() operations, leading to a read-after-free vulnerability. A local attacker could use this to cause a denial of service (system crash) or possibly expose sensitive information. (CVE-2020-29369) Jann Horn discovered that the romfs file system in the Linux kernel did not properly validate file system meta-data, leading to an out-of-bounds read. An attacker could use this to construct a malicious romfs image that, when mounted, exposed sensitive information (kernel memory). (CVE-2020-29371) Jann Horn discovered that the tty subsystem of the Linux kernel did not use consistent locking in some situations, leading to a read-after-free vulnerability. A local attacker could use this to cause a denial of service (system crash) or possibly expose sensitive information (kernel memory). (CVE-2020-29660) Jann Horn discovered a race condition in the tty subsystem of the Linux kernel in the locking for the TIOCSPGRP ioctl(), leading to a use-after- free vulnerability. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2020-29661) It was discovered that a race condition existed that caused the Linux kernel to not properly restrict exit signal delivery. A local attacker could possibly use this to send signals to arbitrary processes. (CVE-2020-35508) Update instructions: The problem can be corrected by updating your system to the following package versions: Ubuntu 20.04 LTS: linux-image-5.6.0-1048-oem 5.6.0-1048.52 linux-image-oem-20.04 5.6.0.1048.44 After a standard system update you need to reboot your computer to make all the necessary changes. ATTENTION: Due to an unavoidable ABI change the kernel updates have been given a new version number, which requires you to recompile and reinstall all third party kernel modules you might have installed. Unless you manually uninstalled the standard kernel metapackages (e.g. linux-generic, linux-generic-lts-RELEASE, linux-virtual, linux-powerpc), a standard system upgrade will automatically perform this as well. References: https://usn.ubuntu.com/4752-1 CVE-2020-10135, CVE-2020-14314, CVE-2020-15436, CVE-2020-15437, CVE-2020-24490, CVE-2020-25212, CVE-2020-25284, CVE-2020-25641, CVE-2020-25643, CVE-2020-25704, CVE-2020-27152, CVE-2020-27815, CVE-2020-28588, CVE-2020-28915, CVE-2020-29368, CVE-2020-29369, CVE-2020-29371, CVE-2020-29660, CVE-2020-29661, CVE-2020-35508 Package Information: https://launchpad.net/ubuntu/+source/linux-oem-5.6/5.6.0-1048.52