xhci: dbgtty: Fix unregister on tty_register_driver() failure
3Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackepss 0.2%
exploitation probability
0.2%top 94% of all CVEs
observed exploitation
nono source reports it
In the Linux kernel, the following vulnerability has been resolved:
xhci: dbgtty: Fix unregister on tty_register_driver() failure
If tty_register_driver() fails, it drops the reference, but fails to set
the global dbc_tty_driver to NULL, causing the unregister to be called
again when module exits.
On module unload dbc_tty_exit() only gates its cleanup on the driver
pointer being non-NULL, so it operates on the already-freed driver:
module_init(xhci_hcd_init)
xhci_hcd_init()
xhci_dbc_init() [return value ignored]
dbc_tty_init()
tty_register_driver() fails
tty_driver_kref_put() -> driver freed
(dbc_tty_driver left dangling)
...
module_exit(xhci_hcd_fini)
xhci_hcd_fini()
xhci_dbc_exit()
dbc_tty_exit()
if (dbc_tty_driver) -> true (dangling)
tty_unregister_driver() -> use-after-free
Affected products
Linux · LinuxReferences
https://git.kernel.org/stable/c/01b7bc0938061f2fd46e0094f6483d8c6c02f7d3https://git.kernel.org/stable/c/0d0faf3cc44c4d86fc6faf5cea972c0fbe00b922https://git.kernel.org/stable/c/0e469b94fbba8eb03666da41dd1082b793c50c1ahttps://git.kernel.org/stable/c/33ed35ca629477f57e0dd1d77d6df96cf5a9eb55https://git.kernel.org/stable/c/43635ff6401ca0e0ed21875379eeded921321525https://git.kernel.org/stable/c/943f976c93e70563b132f5585ff68b08c89641a2https://git.kernel.org/stable/c/a916fa66a43e10f63198b6ce978badffc678821ahttps://git.kernel.org/stable/c/eaca2814f32b9872a332326324b9e83e01f156d2