Messages in this thread | | | Date | Fri, 26 Apr 2019 09:49:56 +0200 | From | Peter Zijlstra <> | Subject | Re: [RFC PATCH 2/7] x86/sci: add core implementation for system call isolation |
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On Fri, Apr 26, 2019 at 12:45:49AM +0300, Mike Rapoport wrote: > The initial SCI implementation allows access to any kernel data, but it > limits access to the code in the following way: > * calls and jumps to known code symbols without offset are allowed > * calls and jumps into a known symbol with offset are allowed only if that > symbol was already accessed and the offset is in the next page > * all other code access are blocked
So if you have a large function and an in-function jump skips a page you're toast.
Why not employ the instruction decoder we have and unconditionally allow all direct JMP/CALL but verify indirect JMP/CALL and RET ?
Anyway, I'm fearing the overhead of this one, this cannot be fast.
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