Description

In the Linux kernel, the following vulnerability has been resolved: usb: phy: fsl-usb: Fix use-after-free in delayed work during device removal The delayed work item otg_event is initialized in fsl_otg_conf() and scheduled under two conditions: 1. When a host controller binds to the OTG controller. 2. When the USB ID pin state changes (cable insertion/removal). A race condition occurs when the device is removed via fsl_otg_remove(): the fsl_otg instance may be freed while the delayed work is still pending or executing. This leads to use-after-free when the work function fsl_otg_event() accesses the already freed memory. The problematic scenario: (detach thread) | (delayed work) fsl_otg_remove() | kfree(fsl_otg_dev) //FREE| fsl_otg_event() | og = container_of(...) //USE | og-> //USE Fix this by calling disable_delayed_work_sync() in fsl_otg_remove() before deallocating the fsl_otg structure. This ensures the delayed work is properly canceled and completes execution prior to memory deallocation. This bug was identified through static analysis.

References 5

• git.kernel.org https://git.kernel.org/stable/c/2e7c47e2eb3cfeadf78a1ccbac8492c60d508f23
• git.kernel.org https://git.kernel.org/stable/c/319f7a85b3c4e34ac2fe083eb146fe129a556317
• git.kernel.org https://git.kernel.org/stable/c/41ca62e3e21e48c2903b3b45e232cf4f2ff7434f
• git.kernel.org https://git.kernel.org/stable/c/4476c73bbbb09b13a962176fca934b32d3954a2e
• git.kernel.org https://git.kernel.org/stable/c/69f9a0701abc3d1f8225074c56c27e6c16a37222

Remediation