4 ms·
One port to rule em all
by out_of_protocol 11y ago
One port to rule em all
- lectrick 11y agoOne port to find them
- WildUtah 11y agoOne port to bring them all and in the darkness bind them.
- the8472 11y agoConsidering the DMA vulnerabilities of thunderbolt, that's not too far off. At least until we have some sort of IOMMU-based hotplug device firewalls in our operating systems.
- TazeTSchnitzel 11y agoUSB 3.0 has DMA too.
- the8472 11y agoBut is that remote DMA? Controller/driver-managed DMA transfers in the fashion of "shovel the next X incoming kilobytes to this memory range" is not the same as arbitrary writes to host memory initiated by a device.
- TazeTSchnitzel 11y agoAh, maybe it isn't, fair point.
- rasz_pl 11y agoOn USB only Host is allowed to be a bus master. Thunderbold does PCI/PCIe and by extension allows any plugged gizmo to take over whole computer.
- lvh 11y agoIsn't that already the case? Current-gen Intel and AMD platforms have IOMMUs; Linux supports them. Linux and Windows support disabling DMA without disabling the rest of e.g. Firewire.
- the8472 11y agoThat's for a specific firewire protocol. Thunderbolt exposes PCIe-lanes, so you can pretty much attach any pcie-device that has drivers. If there are any drivers that do not use the IOMMU properly (just pass through everything?) then we're back to square one. And I don't think all drivers are iommu-aware. The system should only hotplug devices/drivers with user approval.