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

usb: gadget: aspeed-vhub: cancel wake work on device removal

wake_work is armed from the gadget .wakeup callback to resume suspended downstream ports, and it is never cancelled in ast_vhub_remove(), so a work item queued before or during removal can run after devm has freed vhub and its ports, a use-after-free.

Cancelling the work alone is not sufficient: usb_gadget_wakeup() takes no lock and the unbind path never clears wakeup_en, so a remote-wakeup request in flight on another CPU can re-arm the work after the cancel and before vhub is freed.

ast_vhub_del_dev() already clears d->registered under vhub->lock before unregistering the gadget. Refuse the wakeup in ast_vhub_udc_wakeup() once d->registered is clear: the check and the schedule_work() are then atomic against the unbind, so a wakeup that passed before the flag was cleared is drained by the cancel_work_sync() after the del_dev loop, and one that arrives later returns without arming. Also move INIT_WORK() to the top of ast_vhub_probe(), since the probe error path reuses ast_vhub_remove() and would otherwise cancel a never-initialized work item.

This issue was found by an in-house static analysis tool.

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

usb: gadget: aspeed-vhub: cancel wake work on device removal

wake_work is armed from the gadget .wakeup callback to resume suspended downstream ports, and it is never cancelled in ast_vhub_remove(), so a work item queued before or during removal can run after devm has freed vhub and its ports, a use-after-free.

Cancelling the work alone is not sufficient: usb_gadget_wakeup() takes no lock and the unbind path never clears wakeup_en, so a remote-wakeup request in flight on another CPU can re-arm the work after the cancel and before vhub is freed.

ast_vhub_del_dev() already clears d->registered under vhub->lock before unregistering the gadget. Refuse the wakeup in ast_vhub_udc_wakeup() once d->registered is clear: the check and the schedule_work() are then atomic against the unbind, so a wakeup that passed before the flag was cleared is drained by the cancel_work_sync() after the del_dev loop, and one that arrives later returns without arming. Also move INIT_WORK() to the top of ast_vhub_probe(), since the probe error path reuses ast_vhub_remove() and would otherwise cancel a never-initialized work item.

This issue was found by an in-house static analysis tool.

Affected: Ubuntu:16.04:LTS: linux-hwe-edge, Ubuntu:18.04:LTS: linux-aws-5.0, Ubuntu:18.04:LTS: linux-aws-5.3, Ubuntu:Pro:18.04:LTS: linux-aws-5.4, Ubuntu:18.04:LTS: linux-azure, Ubuntu:18.04:LTS: linux-azure-5.3, Ubuntu:Pro:18.04:LTS: linux-azure-5.4, Ubuntu:18.04:LTS: linux-azure-edge, Ubuntu:18.04:LTS: linux-gcp, Ubuntu:18.04:LTS: linux-gcp-5.3 and 219 more

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: aspeed-vhub: cancel wake work on device removal wake_work is armed from the gadget .wakeup callback to resume suspended downstream ports, and it is never cancelled in ast_vhub_remove(), so a work item queued before or during removal can run after devm has freed vhub and its ports, a use-after-free. Cancelling the work alone is not sufficient: usb_gadget_wakeup() takes no lock and the unbind path never clears wakeup_en, so a remote-wakeup request in flight on another CPU can re-arm the work after the cancel and before vhub is freed. ast_vhub_del_dev() already clears d->registered under vhub->lock before unregistering the gadget. Refuse the wakeup in ast_vhub_udc_wakeup() once d->registered is clear: the check and the schedule_work() are then atomic against the unbind, so a wakeup that passed before the flag was cleared is drained by the cancel_work_sync() after the del_dev loop, and one that arrives later returns without arming. Also move INIT_WORK() to the top of ast_vhub_probe(), since the probe error path reuses ast_vhub_remove() and would otherwise cancel a never-initialized work item. This issue was found by an in-house static analysis tool.

Ein Angreifer kann mehrere Schwachstellen im Linux Kernel ausnutzen, um einen nicht näher spezifizierten Angriff durchzuführen, möglicherweise einen Denial-of-Service-Angriff auszulösen, Daten zu manipulieren oder offenzulegen oder Sicherheitsmaßnahmen zu umgehen.