CyberRota Analysis
AI-GeneratedThe vulnerability affects the Linux kernel's USB gadget subsystem, specifically the udc management structure, which is susceptible to a use-after-free condition due to a race condition between memory deallocation and concurrent access. This flaw can lead to a NULL pointer dereference, potentially causing system crashes or instability. Organizations utilizing Linux systems with USB gadget functionality should prioritize addressing this issue to maintain system integrity and prevent potential disruptions.
Original NVD Description
In the Linux kernel, the following vulnerability has been resolved: usb: gadget: udc: Fix use-after-free in gadget_match_driver The udc structure acts as the management structure for the gadget, but their lifecycles are decoupled. A race condition exists where usb_del_gadget() frees the udc memory (e.g., via mode-switch work) while gadget_match_driver() concurrently accesses the freed udc memory (e.g., via configfs), causing a Use-After-Free (UAF) that triggers a NULL pointer dereference when the freed memory is zeroed: [39430.908615][ T1171] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 [39430.911397][ T1171] pc : __pi_strcmp+0x20/0x140 [39430.911441][ T1171] lr : gadget_match_driver+0x34/0x60 ... [39430.911890][ T1171] usb_gadget_register_driver_owner+0x50/0xf8 [39430.911910][ T1171] gadget_dev_desc_UDC_store+0xf4/0x140 [39430.931308][ T1171] configfs_write_iter+0xec/0x134 [39430.957058][ T1171] Workqueue: events_freezable __dwc3_set_mode [39430.957287][ T1171] dwc3_gadget_exit+0x34/0x8c [39430.957304][ T1171] __dwc3_set_mode+0xc0/0x664 Fix this by ensuring the udc structure remains allocated until the gadget is released. To achieve this, introduce a new usb_gadget_release() routine to the core. When the gadget is added, usb_add_gadget() stores the gadget's release routine in the udc structure and takes a reference to the udc. When the gadget is released, usb_gadget_release() drops the reference to the udc and then calls the gadget's release routine.