Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
can: esd_usb: kill anchored URBs before freeing netdevs
esd_usb_disconnect() frees each CAN netdev with free_candev() inside its per-netdev loop and only calls unlink_all_urbs(dev) afterwards. The per-netdev private data (struct esd_usb_net_priv) is embedded in the net_device allocation returned by alloc_candev(), so once free_candev() has run, dev->nets[i] points to freed memory. unlink_all_urbs() then dereferences the freed dev->nets[i] to kill the per-netdev TX anchor (usb_kill_anchored_urbs(&priv->tx_submitted)), clear active_tx_jobs, and reset priv->tx_contexts[].
Reorder the teardown so the anchored URBs are killed before the netdevs are freed, matching other CAN/USB drivers in the same directory such as ems_usb, usb_8dev and mcba_usb, which unregister, then unlink, then free: unregister the netdevs first (which stops their TX queues), call unlink_all_urbs(dev) once, then free the netdevs.
This issue was found by an in-house static analysis tool.
Details
- Affected product:
- Debian 10 ELS
- Affected packages:
- linux @ 4.19.0