On Mon, Aug 22, 2022 at 07:29:53PM +0200, Ard Biesheuvel wrote: > The EFI stub is a wrapper around the core kernel that makes it look like > a EFI compatible PE/COFF application to the EFI firmware. EFI > applications run on top of the EFI runtime, which is heavily based on > so-called protocols, which are struct types consisting [mostly] of > function pointer members that are instantiated and recorded in a > protocol database. > > These structs look like the ideal randomization candidates to the > randstruct plugin (as they only carry function pointers), but of course, > these protocols are contracts between the firmware that exposes them, > and the EFI applications (including our stubbed kernel) that invoke > them. This means that struct randomization for EFI protocols is not a > great idea, and given that the stub shares very little data with the > core kernel that is represented as a randomizable struct, we're better > off just disabling it completely here. > > Reported-by: Daniel Marth <daniel.marth@xxxxxxxxxxxxxxxxx> > Tested-by: Daniel Marth <daniel.marth@xxxxxxxxxxxxxxxxx> > Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx> Acked-by: Kees Cook <keescook@xxxxxxxxxxxx> -Kees -- Kees Cook
