Preface: While it’s technically possible to update UEFI firmware from within a Linux user space environment, it’s not a common or recommended practice. Most UEFI updates are designed to be installed through specific utilities provided by the motherboard manufacturer, often requiring a bootable medium or a dedicated Windows application.
Background: EDK II, also known as EDK2, is an open-source firmware development environment for the Unified Extensible Firmware Interface (UEFI) and Platform Initialization (PI) specifications. It’s a modern, feature-rich, and cross-platform environment developed by the Tianocore project. Think of it as the official development environment for UEFI applications and a core component of many platforms’ firmware
TianoCore is an open-source community focused on developing and promoting the Unified Extensible Firmware Interface (UEFI). It provides a firmware development environment, primarily known as EDK II, which is used for building UEFI firmware, drivers, and applications. TianoCore is a reference implementation of UEFI and is widely adopted by the industry.
Technical details: A researcher reported a bug in the open source EDK2 system management interrupt (SMI) entry code when an MCE occurs near the start of the SMI handler. An attacker who can inject a machine check exception (MCE) could cause execution to jump to an attacker-controlled interrupt handler, leading to arbitration code execution.
Ref: On AMD EPYC processors, the System Management Mode (SMM) functionality is indeed implemented within the System Management Unit (SMU), which is a distinct block of logic on the processor die.
The System Management Unit (SMU) contains a mailbox function to facilitate communication between the SMU and other system components, including the CPU and operating system. This mailbox acts as a communication channel for sending commands and data, and receiving responses, enabling the SMU to perform its tasks related to system management, power management, and hardware control.
Official announcement: Please refer to the following link for detailshttps://www.amd.com/en/resources/product-security/bulletin/amd-sb-7043.html