Linux and automotive computing security

Posted Oct 12, 2012 20:25 UTC (Fri) by ggreen199 (subscriber, #53396)
In reply to: Linux and automotive computing security by PinguTS
Parent article: Linux and automotive computing security

One thing missed on the discussion of replacing CAN with ethernet, is that CAN is priority based. You can prove which message is going to get on the bus at a given time (Because of the priority-based message id's), which you can't do on ethernet. If you were to look at the design of ARINC 664 (real time ethernet IP/TCP on aircraft), you would see that this is not trivial to solve. For critical systems on the car, it is not a slam dunk to replace CAN with ethernet.

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Linux and automotive computing security

Posted Oct 12, 2012 21:05 UTC (Fri) by dlang (guest, #313) [Link] (2 responses)

> You can prove which message is going to get on the bus at a given time (Because of the priority-based message id's)

except for the tiny detail that the priority of the messages is a software thing, so it can be forged.

besides, an easy work-around for needing priority to 'prove' what message will go on a buss first is to just over-provision the network speed to a ridiculous amount. if you were to put in gig-ethernet, the priority is really unlikely to matter as the delay to wait just isn't significant.

Linux and automotive computing security

Posted Oct 12, 2012 21:15 UTC (Fri) by ggreen199 (subscriber, #53396) [Link]

Well of course a rogue box can forge the id but that is the security aspect, the safety aspect is that the priority is hardware determined. Two different things.

And of course you can over-provision the network, except when you are already pushing the limits. If you are near the limit, how do you prove which goes on the bus? This isn't theoretical, we had this very problem (on ethernet, not CAN). So where CAN does what you need, I stand by my comment it is not a slam-dunk to replace it. Just putting in ethernet doesn't prove you will meet your real-time milestone when you HAVE to.

Linux and automotive computing security

Posted Oct 16, 2012 18:20 UTC (Tue) by Baylink (guest, #755) [Link]

Not according to other comments in this thread, which suggest that Canbus transceivers can be provisioned on a board which are *physically incapable* of generating high-priority addresses.