Messages in this thread | | | Date | Tue, 4 Jul 2017 17:46:35 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [PATCH v2 2/2] x86/boot/KASLR: Restrict kernel to be randomized in mirror regions |
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On Tue, 4 Jul 2017, Matt Fleming wrote: > On Tue, 04 Jul, at 04:46:58PM, Thomas Gleixner wrote: > > On Tue, 4 Jul 2017, Baoquan He wrote: > > > > > In fact I just referred to code in setup_arch(). Now I have a question, > > > though CONFIG_EFI=y but efi firmware is not enabled, > > > boot_params.efi_info.efi_loader_signature should be initilized to 0. > > > Then below code is also problematic. > > > > > > #ifdef CONFIG_EFI > > > if (!strncmp((char *)&boot_params.efi_info.efi_loader_signature, > > > EFI32_LOADER_SIGNATURE, 4)) { > > > set_bit(EFI_BOOT, &efi.flags); > > > } else if (!strncmp((char *)&boot_params.efi_info.efi_loader_signature, > > > EFI64_LOADER_SIGNATURE, 4)) { > > > set_bit(EFI_BOOT, &efi.flags); > > > set_bit(EFI_64BIT, &efi.flags); > > > } > > > > > > if (efi_enabled(EFI_BOOT)) > > > efi_memblock_x86_reserve_range(); > > > #endif > > > > Indeed. Matt? > > It's possibly that I'm missing some context, but boot_params should be > zero'd -- the x86 boot protocol requires that the entire data > structure be zero'd on allocation. > > Have I missed something?
No. I misread the code. The strncmp() operates on boot_params.efi_info.efi_loader_signature itself, so yes, all is fine.
It's just Baoquans copy and paste wreckage which is busted.
Thanks,
tglx
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