3 ms·

it can't and it shouldn't IF IOMMUs were properly used

by csdvrx 3y ago

MadnessASAP 3y ago
If I can put my paranoia cap on for a moment. The baseband processor having privileged access to the main processor may be a "feature" not a bug. It's a powerful processor, that is running constantly, has unlimited and continuous inscrutable communication with the network, is the gatekeeper for the main processors communication with the network, and it's firmware is practically required by regulations to be an opaque blob. Seems to be pretty much the ideal place for nefarious deeds.
- csdvrx 3y ago
  > The baseband processor having privileged access to the main processor may be a "feature" not a bug yes but iff with the qualifier of "in old systems, where permissions were a tree-like state where root/uid0 could see what unpriviledged users would do - by design" It's a dated design. More separation is needed, like what was achieved for virtualization or containers (namespaces) > it's firmware is practically required by regulations to be an opaque blob That's another problem, but I think it also comes from thinking in a tree-like state system. Ideally, a device shouldn't be able to take down a well designed network: if you plug a bad appliance in your AC, it will not crash the power grub: it'll just trip a fuse.
  - MadnessASAP 3y ago
    I don't disagree with any of that. My point being that the people with the power to make the change have no desire too.
    - tptacek 3y ago
      I'm not sure what you're talking about, because the modern flagship phones all have the architecture you're saying they should have but don't because of the "people with the power".
fulafel 3y ago
Indeed, hardware security building blocks are just that, necessary but not sufficient. Eg Unix and Windows took a very long time from "we have hardware MMU and are using it for some stuff" to "we have a real world tried and tested, somewhat working multiuser security separation".

it can't and it shouldn't IF IOMMUs were properly used

by csdvrx 3y ago

it can't and it shouldn't IF IOMMUs were properly used

If I can put my paranoia cap on for a moment. The baseband processor having privileged access to the main processor may be a "feature" not a bug. It's a powerful processor, that is running constantly, has unlimited and continuous inscrutable communication with the network, is the gatekeeper for the main processors communication with the network, and it's firmware is practically required by regulations to be an opaque blob. Seems to be pretty much the ideal place for nefarious deeds.

csdvrx 3y ago
> The baseband processor having privileged access to the main processor may be a "feature" not a bug yes but iff with the qualifier of "in old systems, where permissions were a tree-like state where root/uid0 could see what unpriviledged users would do - by design" It's a dated design. More separation is needed, like what was achieved for virtualization or containers (namespaces) > it's firmware is practically required by regulations to be an opaque blob That's another problem, but I think it also comes from thinking in a tree-like state system. Ideally, a device shouldn't be able to take down a well designed network: if you plug a bad appliance in your AC, it will not crash the power grub: it'll just trip a fuse.
- MadnessASAP 3y ago
  I don't disagree with any of that. My point being that the people with the power to make the change have no desire too.
  - tptacek 3y ago
    I'm not sure what you're talking about, because the modern flagship phones all have the architecture you're saying they should have but don't because of the "people with the power".

fulafel 3y ago

Indeed, hardware security building blocks are just that, necessary but not sufficient. Eg Unix and Windows took a very long time from "we have hardware MMU and are using it for some stuff" to "we have a real world tried and tested, somewhat working multiuser security separation".