[LSN-0075-1] Linux kernel vulnerability

Linux kernel vulnerabilities
A security issue affects these releases of Ubuntu and its derivatives:
– Ubuntu 18.04 LTS – Ubuntu 20.04 LTS – Ubuntu 16.04 LTS – Ubuntu 14.04 ESM
Summary
Several security issues were fixed in the kernel.
Software Description
– linux – Linux kernel – linux-aws – Linux kernel for Amazon Web Services (AWS) systems – linux-azure – Linux kernel for Microsoft Azure Cloud systems – linux-gcp – Linux kernel for Google Cloud Platform (GCP) systems – linux-gke – Linux kernel for Google Container Engine (GKE) systems – linux-gkeop – Linux kernel for Google Container Engine (GKE) systems – linux-oem – Linux kernel for OEM systems
Details
Piotr Krysiuk discovered that the BPF subsystem in the Linux kernel did not properly apply speculative execution limits on some pointer types. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2020-27170)
Piotr Krysiuk discovered that the BPF subsystem in the Linux kernel did not properly compute a speculative execution limit on pointer arithmetic in some situations. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2020-27171)
Jann Horn discovered that a race condition existed in the madvise implementation in the Linux kernel, leading to a use-after-free vulnerability. A local attacker could use this to cause a denial of service (system crash). (CVE-2020-29372)
It was discovered that the memory management subsystem in the Linux kernel did not properly handle copy-on-write operations in some situations. A local attacker could possibly use this to gain unintended write access to read-only memory pages. (CVE-2020-29374)
De4dCr0w of 360 Alpha Lab discovered that the BPF verifier in the Linux kernel did not properly handle mod32 destination register truncation when the source register was known to be 0. A local attacker could use this to expose sensitive information (kernel memory) or possibly execute arbitrary code. (CVE-2021-3444)
Adam Nichols discovered that the iSCSI subsystem in the Linux kernel did not properly restrict access to iSCSI transport handles. A local attacker could use this to cause a denial of service or expose sensitive information (kernel pointer addresses). (CVE-2021-27363)
Adam Nichols discovered that an out-of-bounds read existed in the iSCSI subsystem in the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or expose sensitive information (kernel memory). (CVE-2021-27364)
Adam Nichols discovered that heap overflows existed in the iSCSI subsystem in the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2021-27365)
Update instructions
The problem can be corrected by updating your kernel livepatch to the following versions:
Ubuntu 18.04 LTS aws – 75.2 generic – 75.2 gke – 75.2 gkeop – 75.2 lowlatency – 75.2 oem – 75.2
Ubuntu 20.04 LTS aws – 75.2 azure – 75.2 gcp – 75.2 generic – 75.2 gke – 75.2 gkeop – 75.2 lowlatency – 75.2
Ubuntu 16.04 LTS aws – 75.3 azure – 75.2 generic – 75.3 lowlatency – 75.3
Ubuntu 14.04 ESM generic – 75.3 lowlatency – 75.3
Support Information
Kernels older than the levels listed below do not receive livepatch updates. If you are running a kernel version earlier than the oneĀ  listed below, please upgrade your kernel as soon as possible.
Ubuntu 18.04 LTS linux-aws – 4.15.0-1054 linux-gke-4.15 – 4.15.0-1076 linux-gke-5.4 – 5.4.0-1009 linux-gkeop-5.4 – 5.4.0-1007 linux-hwe-5.4 – 5.4.0-26 linux-oem – 4.15.0-1063 linux – 4.15.0-69
Ubuntu 20.04 LTS linux-aws – 5.4.0-1009 linux-azure – 5.4.0-1010 linux-gcp – 5.4.0-1009 linux-gke – 5.4.0-1033 linux-gkeop – 5.4.0-1009 linux-oem – 5.4.0-26 linux – 5.4.0-26
Ubuntu 16.04 LTS linux-aws – 4.4.0-1098 linux-azure – 4.15.0-1063 linux-hwe – 4.15.0-69 linux – 4.4.0-168
Ubuntu 14.04 ESM linux-lts-xenial – 4.4.0-168
References
– CVE-2020-27170 – CVE-2020-27171 – CVE-2020-29372 – CVE-2020-29374 – CVE-2021-3444 – CVE-2021-27363 – CVE-2021-27364 – CVE-2021-27365