MGASA-2023-0243

This kernel-linus update is based on upstream 5.15.122 and fixes atleast the following security issues:

Under specific microarchitectural circumstances, a register in "Zen 2" CPUs may not be written to 0 correctly. This may cause data from another process and/or thread to be stored in the YMM register, which may allow an attacker to potentially access sensitive information (CVE-2023-20593, also known as Zenbleed).

This update adds a kernel-side mitigation for this issue to protect users until Amd gets their fixed microcode / AGESA updates out for all affected CPUs. The fixed microcode for Amd EPYC gen2 is available in the microcode-0.20230613-2.mga8.nonfree package. For other affected CPUs, see the referenced amd.com url that has info about estimated microcode update timelines for various CPUs.

Linux Kernel nftables Use-After-Free Local Privilege Escalation Vulnerability; nftchainlookupbyid() failed to check whether a chain was active and CAPNET_ADMIN is in any user or network namespace (CVE-2023-31248).

Linux Kernel nftables Out-Of-Bounds Read/Write Vulnerability; nftbyteorder poorly handled vm register contents when CAPNET_ADMIN is in any user or network namespace (CVE-2023-35001).

For other upstream fixes in this update, see the referenced changelogs.