| Date | Thu, 24 Feb 2022 16:42:51 -0800 | From | Kees Cook <> | Subject | Re: [PATCH v2 07/39] x86/entry: Sprinkle ENDBR dust |
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On Thu, Feb 24, 2022 at 03:51:45PM +0100, Peter Zijlstra wrote: > The SYSCALL entry points are found through taking their respective > address in order to program them in the MSRs, while the exception > entry points are found through UNWIND_HINT_IRET_REGS.
Stupid question: does CET consider exception and syscall entry points to be indirect calls? (I would expect so, but they're ever so slightly differently executed...)
> [...] > 0 : > + ENDBR > .byte 0x6a, vector > jmp asm_common_interrupt > - nop > - /* Ensure that the above is 8 bytes max */ > - . = 0b + 8 > + /* Ensure that the above is IDT_ALIGN bytes max */ > + .fill 0b + IDT_ALIGN - ., 1, 0x90
IIUC, these are just padding -- let's use 0xcc instead of 0x90 as we do in other places (e.g. vmlinux.lds.S).
-- Kees Cook
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