Userspace with DPL 0.

[AlexHully]

Hi,

Could userspace still being considered userspace if it doesn't mess with the kernel virtual space but use DPL 0 permission (it can alter interrupt states and so on)?

Granted, that can be dangerous and let all sorts of bad things happen.

But, is it still considered userspace?

Bye

[Brendan]

Hi,

Could userspace still being considered userspace if it doesn't mess with the kernel virtual space but use DPL 0 permission (it can alter interrupt states and so on)?

Yes; it could still be considered user space (but couldn't be considered secure, unless the OS is doing something else to ensure isolation - e.g. managed code).

Don't forget that you could set IOPL=3 to allow CPL=3 tasks to use some things (HLT, CLI/STI, IO ports) without given them full access to things like CR0, CR3, MSRs, etc.


Cheers,

Brendan

[AlexHully]

Perfect.

Thanks a lot Brendan