Exploiting System Management Mode with a very long interrupt

nazgulsenpai

I'm amused at the lengths the readme goes to in order to drive home the fact that this needs to be a LOOOOOOOOOOOOOOOOOOOONG instruction, including the unnecessarily long code block illustration. The topic is interesting anyway, but that makes it way more entertaining.

londons_explore

Unclear why there is a 1 second timeout at all. Presumably the patch for that will be to make it an infinity timeout.

kmeisthax

...huh, I was wondering why serial machine code prankster xoreaxeaxeax was keeping lists of extremely long-running instructions. Hopefully this is at least only possible in kernel mode, right? Right?!

mike_hearn

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

Liftyee

I don't know much about the specifics of CPU architecture apart from the existence of assembly and different modes. Either way the explanation was still entertaining and interesting. smiiiiiiii