CyberRota Analysis
AI-GeneratedThe vulnerability affects the Linux kernel's handling of Type-C connectors, specifically during the unbinding process of Thunderbolt docks. A race condition can lead to a use-after-free scenario, where a stale pointer is dereferenced, resulting in potential system instability and failure to enumerate connected devices. Organizations using Linux systems with Thunderbolt docks should prioritize addressing this vulnerability to prevent operational disruptions and ensure device reliability.
Original NVD Description
In the Linux kernel, the following vulnerability has been resolved: usb: core: port: Deattach Type-C connector on component unbind connector_unbind() is the mirror of connector_bind(), but it is missing the symmetric call to typec_deattach() that connector_bind() makes via: if (port_dev->child) typec_attach(port_dev->connector, &port_dev->child->dev); When a Thunderbolt dock is unplugged, two teardown paths race: 1. The component framework calls connector_unbind() first, which sets port_dev->connector = NULL without calling typec_deattach(). This leaves port->usb2_dev/port->usb3_dev in struct typec_port pointing at the USB device that is about to be freed. 2. usb_disconnect() then calls typec_deattach(port_dev->connector, ...), but port_dev->connector is already NULL, so the call is a no-op and port->usb2_dev is never cleared. 3. Concurrently, UCSI detects a PD partner-disconnect event and calls typec_unregister_partner(), which reads port->usb2_dev (now a dangling pointer to freed memory) and passes it to typec_partner_unlink_device() -> sysfs_remove_link() -> dev_name() on the freed device, corrupting the typec/UCSI partner state. This corruption leaves the Thunderbolt tunnel in an inconsistent state on the next dock hot-plug. On affected hardware the dock's I225/igc NIC fails to enumerate: AER fires a slot reset while the igc driver is still initialising ("PCIe link lost"), and the subsequent igc_reset attempt hits igc_rd32 on an already-detached device: igc 0000:2e:00.0 eth0: PCIe link lost, device now detached igc: Failed to read reg 0x0! WARNING: CPU: 9 PID: 129 at drivers/net/ethernet/intel/igc/igc_main.c:7005 igc_rd32+0xa4/0xc0 [igc] Call Trace: igc_disable_pcie_master+0x16/0xa0 [igc] igc_reset_hw_base+0x14/0x170 [igc] igc_reset+0x63/0x110 [igc] igc_io_slot_reset+0x9e/0xd0 [igc] report_slot_reset+0x5d/0xc0 pcie_do_recovery+0x209/0x400 aer_isr_one_error_type+0x235/0x430 aer_isr+0x4e/0x80 irq_thread+0xf4/0x1f0 4. UCSI later handles the PD partner-disconnect and calls typec_unregister_partner(), which still sees the stale port->usb2_dev and tries to remove its sysfs link a second time: kernfs: can not remove 'typec', no directory WARNING: CPU: 6 PID: 55 at fs/kernfs/dir.c:1706 kernfs_remove_by_name_ns+0xe9/0xf0 Workqueue: events ucsi_handle_connector_change [typec_ucsi] Call Trace: sysfs_remove_link+0x19/0x50 typec_unregister_partner+0x6e/0x120 [typec] ucsi_unregister_partner+0x107/0x150 [typec_ucsi] ucsi_handle_connector_change+0x3ec/0x490 [typec_ucsi] process_one_work+0x18e/0x3e0 worker_thread+0x2e3/0x420 kthread+0x10a/0x230 ret_from_fork+0x121/0x140 ret_from_fork_asm+0x1a/0x30 With worse timing the same stale pointer is dereferenced after the backing memory is freed, turning the warning into a use-after-free. Fix the asymmetry: call typec_deattach() before clearing port_dev->connector, matching what connector_bind() does on the bind side. typec_partner_deattach() is already protected by port->partner_link_lock, so it serialises safely with the concurrent typec_unregister_partner() path.