usb: typec: ucsi: ccg: Fix use-after-free of ucsi on remove
3Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackepss 0.2%
exploitation probability
0.2%top 93% of all CVEs
observed exploitation
nono source reports it
In the Linux kernel, the following vulnerability has been resolved:
usb: typec: ucsi: ccg: Fix use-after-free of ucsi on remove
The threaded IRQ handler ccg_irq_handler() calls ucsi_notify_common(),
which on a connector-change event calls ucsi_connector_change() and
schedules connector work. In ucsi_ccg_remove(), ucsi_destroy() frees
uc->ucsi (kfree) before free_irq() is called, so a handler invocation
already in flight may access the freed object after ucsi_destroy().
CPU 0 (remove) | CPU 1 (threaded IRQ)
ucsi_destroy(uc->ucsi) | ccg_irq_handler()
kfree(ucsi) // FREE | ucsi_notify_common(uc->ucsi) // USE
Move free_irq() before ucsi_destroy() in the remove path. It is kept
after ucsi_unregister(): ucsi_unregister() cancels connector work whose
handler issues GET_CONNECTOR_STATUS through ucsi_send_command_common(),
which waits for a completion that is signalled from the IRQ handler, so
the IRQ must stay active until that work has been cancelled.
The probe error path already orders free_irq() before ucsi_destroy().
This bug was found by static analysis.
Affected products
Linux · LinuxReferences
https://git.kernel.org/stable/c/1a160076d3d0dcd4a98a4599ad96eec0790b099bhttps://git.kernel.org/stable/c/1f0bdc2884b67de337215079bba166df0cdf4ac5https://git.kernel.org/stable/c/86c9ee928c4a370e323e432aaf8dca79c4ba7c85https://git.kernel.org/stable/c/99381e762273a2410a3f0216000be32b013c0ea9https://git.kernel.org/stable/c/c32df11147822d22facee8fa30c2e8971d12f426https://git.kernel.org/stable/c/dbb500bad02146b388041877574829016591ddc8https://git.kernel.org/stable/c/f1adeb1ff8bef1467d6961059810795d02bbad5dhttps://git.kernel.org/stable/c/f5c772b76bbd95de8be51cf849c6098f6af6fcf9