Linux Kernel up to 6.10.4 IRQ sc16is7xx_startup privilege escalation

Summaryinfo

A vulnerability described as problematic has been identified in Linux Kernel up to 6.10.4. Affected by this vulnerability is the function sc16is7xx_startup of the component IRQ Handler. The manipulation results in an unknown weakness. This vulnerability is known as CVE-2024-44950. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.10.4. It has been classified as problematic. Affected is the function sc16is7xx_startup of the component IRQ Handler. The impact remains unknown. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: serial: sc16is7xx: fix invalid FIFO access with special register set When enabling access to the special register set, Receiver time-out and RHR interrupts can happen. In this case, the IRQ handler will try to read from the FIFO thru the RHR register at address 0x00, but address 0x00 is mapped to DLL register, resulting in erroneous FIFO reading. Call graph example: sc16is7xx_startup(): entry sc16is7xx_ms_proc(): entry sc16is7xx_set_termios(): entry sc16is7xx_set_baud(): DLH/DLL = $009C --> access special register set sc16is7xx_port_irq() entry --> IIR is 0x0C sc16is7xx_handle_rx() entry sc16is7xx_fifo_read(): --> unable to access FIFO (RHR) because it is mapped to DLL (LCR=LCR_CONF_MODE_A) sc16is7xx_set_baud(): exit --> Restore access to general register set Fix the problem by claiming the efr_lock mutex when accessing the Special register set.

The advisory is shared for download at git.kernel.org. This vulnerability is traded as CVE-2024-44950 since 08/21/2024. There are known technical details, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 208423 (SUSE SLES15 / openSUSE 15 Security Update : kernel (SUSE-SU-2024:3551-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.10.5 eliminates this vulnerability. Applying the patch 6a6730812220/7d3b793faaab is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (208423). Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.10.0
• 6.10.1
• 6.10.2
• 6.10.3
• 6.10.4

License

• open-source

Website

• Vendor: https://www.kernel.org/

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Once again VulDB remains the best source for vulnerability data.

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