Re: [PATCH v6 RESEND] x86/boot/KASLR: Restrict kernel to be randomized in mirror regions

From: Matt Fleming
Date: Mon Jul 24 2017 - 09:34:22 EST


On Fri, 21 Jul, at 09:19:56PM, Baoquan He wrote:
>
> There are places where the efi map is getting and used like this. E.g
> in efi_high_alloc() of drivers/firmware/efi/libstub/efi-stub-helper.c.
> EFI developers worry the size of efi_memory_desc_t could not be the same
> as e->efi_memdesc_size?
>
> Hi Matt,
>
> Could you help have a look at this?

You're exactly right. The code guards against the size of the
efi_memory_desc_t struct changing. The UEFI spec says to traverse the
memory map this way.