Comment by mike_hearn
3 days ago
The designers of the firmware anticipate this attack but punt it to the vendor, apparently:
//
// Platform implementor should choose a timeout value appropriately:
[snip]
// - The timeout value must be longer than longest possible IO operation in the system
I wonder whether a Thunderbolt accessory can cause arbitrarily long IO operations. What's the upper bound before some other layer gives up and causes the instruction to fault?
No need. Thunderbolt is usually susceptible to DMA attacks.