CVE-2024-56545

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

HID: hyperv: streamline driver probe to avoid devres issues

It was found that unloading hid_hyperv module results in a devres complaint:

… hv_vmbus: unregistering driver hid_hyperv ————[ cut here ]———— WARNING: CPU: 2 PID: 3983 at drivers/base/devres.c:691 devres_release_group+0x1f2/0x2c0 … Call Trace: ? devres_release_group+0x1f2/0x2c0 ? __warn+0xd1/0x1c0 ? devres_release_group+0x1f2/0x2c0 ? report_bug+0x32a/0x3c0 ? handle_bug+0x53/0xa0 ? exc_invalid_op+0x18/0x50 ? asm_exc_invalid_op+0x1a/0x20 ? devres_release_group+0x1f2/0x2c0 ? devres_release_group+0x90/0x2c0 ? rcu_is_watching+0x15/0xb0 ? __pfx_devres_release_group+0x10/0x10 hid_device_remove+0xf5/0x220 device_release_driver_internal+0x371/0x540 ? klist_put+0xf3/0x170 bus_remove_device+0x1f1/0x3f0 device_del+0x33f/0x8c0 ? __pfx_device_del+0x10/0x10 ? cleanup_srcu_struct+0x337/0x500 hid_destroy_device+0xc8/0x130 mousevsc_remove+0xd2/0x1d0 [hid_hyperv] device_release_driver_internal+0x371/0x540 driver_detach+0xc5/0x180 bus_remove_driver+0x11e/0x2a0 ? __mutex_unlock_slowpath+0x160/0x5e0 vmbus_driver_unregister+0x62/0x2b0 [hv_vmbus] …

And the issue seems to be that the corresponding devres group is not allocated. Normally, devres_open_group() is called from __hid_device_probe() but Hyper-V HID driver overrides hid_dev->driver with mousevsc_hid_driver stub and basically re-implements __hid_device_probe() by calling hid_parse() and hid_hw_start() but not devres_open_group(). hid_device_probe() does not call __hid_device_probe() for it. Later, when the driver is removed, hid_device_remove() calls devres_release_group() as it doesnt check whether hdev->driver was initially overridden or not.

The issue seems to be related to the commit 62c68e7cee33 (HID: ensure timely release of driver-allocated resources) but the commit itself seems to be correct.

Fix the issue by dropping the hid_dev->driver override and using hid_register_driver()/hid_unregister_driver() instead. Alternatively, it would have been possible to rely on the default handling but HID_CONNECT_DEFAULT implies HID_CONNECT_HIDRAW and it doesnt seem to work for mousevsc as-is.

Affected Software

References

• https://git.kernel.org/stable/c/19a9457e5e210e408c1f8865b5d93c5a2c90409d
• https://git.kernel.org/stable/c/3d48d0fbaaa74a04fb9092780a3f83dc4f3f8160
• https://git.kernel.org/stable/c/66ef47faa90d838cda131fe1f7776456cc3b59f2
• https://git.kernel.org/stable/c/b03e713a400aeb5f969bab4daf47a7402d0df814