[PATCH 4/4] ef/libstub: arm/arm64: randomize the base of the UEFI rt services region

Hi Ard,

On 07/04/17 16:51, Ard Biesheuvel wrote:

That is quite interesting, to be honest, because that patch should
effectively be a NOP on systems that do not implement
EFI_RNG_PROTOCOL.

Could you run this from the UEFI shell please?

http://people.linaro.org/~ard.biesheuvel/RngTest.efi

As you predicted:

Shell> RngTest.efi
UEFI RNG Protocol Testing :
----------------------------
 -- Locate UEFI RNG Protocol : [Fail - Status = Not Found]
Error reported: Not Found

I would expect it to report that it has no EFI_RNG_PROTOCOL
implementation. Could you also check whether the working kernel still
works /after/ having executed that utility?

The broken kernel remains broken after running that test. reboot. The working
kernel continues to work after running that test.

(On Monday) I will try with just these efi changes on v4.11-rc. to try and
eliminate everything else in linux-next.

This is one of those firmware versions that prints lots of

efi: [Firmware Bug]: IRQ flags corrupted (0x00000140=>0x00000100) by EFI

get_variable


Thanks,

James