Linux vulnerability

What happened

In the Linux kernel, the following vulnerability has been resolved: i3c: master: Fix info leak and UAF in device unregister path i3c_master_unregister_i3c_devs() clears i3cdev->dev->desc before calling device_unregister(). During device_unregister(), device_del() emits a KOBJ_REMOVE uevent and unbinds the driver while the device descriptor is still expected to be valid. As a result, i3c_device_uevent() and a racing modalias_show() can observe a NULL desc and fall back to an uninitialized stack struct i3c_device_info, leaking kernel stack contents in the generated modalias. Driver .remove() callbacks may also encounter an unexpected NULL desc during unbind. Keep desc valid until device_unregister() has completed. Since device_unregister() drops the device reference and may free the device, take an extra reference with get_device() before unregistering. Clear desc afterwards and release the extra reference with put_device(). This preserves the release-time invariant that desc must be NULL while avoiding both the information leak and a potential use-after-free from writing desc after the device has been released.

Affected versions

Linux: 3a379bbcea0af6280e1ca0d1edfcf4e68cde6ee0 through before c16b6f25e0cc2dd1055dde1256cbf5a9e888cf49 (git); 3a379bbcea0af6280e1ca0d1edfcf4e68cde6ee0 through before 94fb9786d67a8f8b899e77381620f86bad94fdf7 (git); 3a379bbcea0af6280e1ca0d1edfcf4e68cde6ee0 through before 4837be0f9ac2efe5e83b35a696b6242c473d280c (git); 3a379bbcea0af6280e1ca0d1edfcf4e68cde6ee0 through before d2c743efd2d1ee64e94324664808f623dd865872 (git); 5.0 Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

• Apply vendor-provided updates or mitigations.
• Review affected product exposure and access logs.