CVE-2026-72113can: bcm: add missing device refcount for CAN filter removal

Official description

In the Linux kernel, the following vulnerability has been resolved: can: bcm: add missing device refcount for CAN filter removal sashiko-bot remarked a problem with a concurrent device unregistration in isotp.c which also is present in the bcm.c code. A former fix for raw.c commit c275a176e4b6 ("can: raw: add missing refcount for memory leak fix") introduced a netdevice_tracker which solves the issue for bcm.c too. bcm_release(), bcm_delete_rx_op() and bcm_notifier() relied on dev_get_by_index(ifindex) to re-find the device for an rx_op before unregistering its filter. If a concurrent NETDEV_UNREGISTER has already unlisted the device from the ifindex table, that lookup fails and can_rx_unregister() is silently skipped, leaving a stale CAN filter pointing at the soon-to-be-freed bcm_op/socket. Hold a netdev_hold()/netdev_put() tracked reference on op->rx_reg_dev from the moment the rx filter is registered in bcm_rx_setup() until it is unregistered in bcm_rx_unreg(), and use that reference directly in bcm_release() and bcm_delete_rx_op() instead of re-looking the device up by ifindex.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/bd5232663524e94cc5aad861dca11e3db8e2ab6f
• https://git.kernel.org/stable/c/ee8b36d0faca08f35b889b6e9aa850695e5b8ba9
• https://git.kernel.org/stable/c/dcaee869913c7210cd47ed0a8f27349d7bdcdb7b
• https://git.kernel.org/stable/c/84aa4807816e405c1bf87114fc63e06d244281ef
• https://git.kernel.org/stable/c/633bda66fbf309f5de5e1ad6defe8e6b1d77a20f
• https://git.kernel.org/stable/c/b024c21c9066f6957b7d4a8f2037e4b000c5e041
• https://git.kernel.org/stable/c/04d23061bbf18d5d81022eb21e9d32e99d24468d
• https://git.kernel.org/stable/c/d59948293ea34b6337ce2b5febab8510de70048c