Your Ethernet controller and hard drive controller don’t really need to talk to anything else. If either is compromised, it’s already bad.
Ever hear of DMA, dude?
Isn't that a feature of the CPU though?
*edit sorry I am wrong. DMA seems to bypass the CPU [1]
1. https://www.csoonline.com/article/2607924/security/stop-snea...
Re:iMac Pro's T2 chip
by godelmachine on Thursday January 04, 2018 @01:05PM
(#16072503)
I was about to correct you when you edited your own comment !! :)
Not having a central controller multiple subsystem vendors would have to cooperate using an agreed DMA communication protocol to monitor you and send the information back using the wifi/ethernet chip. Possible but unlikely.
The DMA communication protocol is already defined. It is part of PCIExpress.
Re:iMac Pro's T2 chip
by walterbell on Thursday January 04, 2018 @11:16PM
(#16076485)
On the iMac Pro, will PCI devices be able to DMA into both the Intel and ARM CPUs? Is there a single IOMMU which will arbitrate DMA for both CPUs?
The IOMMU functionality is built into the Platform Controller Hub, which is between the baseboard management controller (the ARM) and the main processor.
Theoretically it would be possible to prevent DMA between the two, but it is highly doubtful Apple would program it that way.
So if you don't have control over a peripheral (say your GPU for example) then yes, it could be doing things you have no control over. But it can't interfere with anything else unless the CPU says so.
But if you don't have control over your CPU, the "central" processing unit, then it's game over.