Messages in this thread | | | Date | Tue, 04 Jun 2013 11:15:59 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH v13 3/3] trace,x86: Add irq vector tracepoints |
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On 06/03/2013 04:53 PM, Steven Rostedt wrote: > > This way we wont be opening up any easy root holes where if a process > finds a way to modify some arbitrary kernel memory, we can prevent it > from modifying the current_idt_descr_ptr and have a nice way to exploit > the IDT. Sure, one can argue that if they can modify arbitrary kernel > memory, we may already be lost, but lets not make it easier for them > than need be. >
I don't like current_idt_descr_ptr if we can avoid it. It is a direct proxy for reading and writing the original IDT, in other words, it really hasn't really addressed the issue.
What I'm thinking we really should have is a function that returns the IDT that we currently should be using, based on the current state. If that state is, say, tracing on/off and NMI on/off, then that can be indicated by bits in a state vector.
The point is that the IDT address itself should not be mutable state if it can be at all avoided.
-hpa
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