LSM policy options for new GPIO kernel driver interface

Weber, Matthew L Collins Matthew.Weber at
Mon Aug 2 17:08:14 UTC 2021


Since the 5.10 kernel, the GPIO subsystem has migrated from a sysfs based GPIO export method [1] (everything is a file) to a character device[2] + library[3].  The new framework[2] provides users with signal debouncing and other features that benefit embedded products.  The legacy method[1] allowed fine policy control of who can export / set / get the GPIO state.  We have not found a similar security policy path with the new approach.  Has anyone brainstormed strategies for the new character device-based interface without adding a userspace broker to enforce another level of rules?  The ideal case would be to keep all the controls within the SELinux refpolicy such that testing can be all-inclusive.

I'd be interested in what people think, such that I can prepare a university research project submission for Fall 2021 to build a prototype. 

Best Regards,
Matt Weber


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