Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

usb: typec: ucsi: ccg: Fix use-after-free of ucsi on remove

The threaded IRQ handler ccg_irq_handler() calls ucsi_notify_common(), which on a connector-change event calls ucsi_connector_change() and schedules connector work. In ucsi_ccg_remove(), ucsi_destroy() frees uc->ucsi (kfree) before free_irq() is called, so a handler invocation already in flight may access the freed object after ucsi_destroy().

CPU 0 (remove) | CPU 1 (threaded IRQ) ucsi_destroy(uc->ucsi) | ccg_irq_handler() kfree(ucsi) // FREE | ucsi_notify_common(uc->ucsi) // USE

Move free_irq() before ucsi_destroy() in the remove path. It is kept after ucsi_unregister(): ucsi_unregister() cancels connector work whose handler issues GET_CONNECTOR_STATUS through ucsi_send_command_common(), which waits for a completion that is signalled from the IRQ handler, so the IRQ must stay active until that work has been cancelled.

The probe error path already orders free_irq() before ucsi_destroy().

This bug was found by static analysis.