Linux Kernel PCI: Mediatek-Gen3 IRQ Domain Leak Vulnerability

A vulnerability in the Linux kernel's PCI Mediatek Gen3 controller has been addressed. The issue involved improper handling of IRQ domains in the 'mtk_pcie_setup_irq()' function. IRQ domains were allocated before retrieving the controller's IRQ. If the IRQ retrieval failed, the function returned an error without cleaning up the allocated domains, potentially leading to a resource leak. The vulnerability has been fixed by changing the order of operations, ensuring that IRQ domains are allocated only after successfully fetching the controller's IRQ.

Impact

The vulnerability could lead to a resource leak by failing to clean up allocated IRQ domains when an error occurs during IRQ retrieval, as noted in the upstream commit.

Reproduction

To reproduce this vulnerability, allocate IRQ domains in the 'mtk_pcie_setup_irq()' function before retrieving the controller's IRQ. If the IRQ retrieval fails, the function will return an error without cleaning up the allocated domains, causing a resource leak.

Remediation

Users can apply the latest patches available in the Linux kernel stable tree to address this vulnerability.