linux-kernel - Re: [PATCH] x86/efi: skip memattr table on kexec boot

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <CAMj1kXH6yorrBNYyuO2YrX_Q4cCW8LoyHOZMb=a5k0Euuooznw@mail.gmail.com>
Date: Thu, 23 Jan 2025 10:17:51 +0100
From: Ard Biesheuvel <ardb@...nel.org>
To: Dave Young <dyoung@...hat.com>
Cc: Usama Arif <usamaarif642@...il.com>, linux-kernel@...r.kernel.org, 
	linux-efi@...r.kernel.org, Breno Leitao <leitao@...ian.org>, kexec@...ts.infradead.org, 
	x86@...nel.org
Subject: Re: [PATCH] x86/efi: skip memattr table on kexec boot

On Thu, 23 Jan 2025 at 07:36, Dave Young <dyoung@...hat.com> wrote:
>
> efi_memattr_init() added a sanity check to avoid firmware caused corruption.
> The check is based on efi memmap entry numbers, but kexec only takes the
> runtime related memmap entries thus this caused many false warnings, see
> below thread for details:
>
> https://lore.kernel.org/all/20250108215957.3437660-2-usamaarif642@gmail.com/
>
> Ard suggests to skip the efi memattr table in kexec, this makes sense because
> those memattr fixups are not critical.
>
> Reported-by: Breno Leitao <leitao@...ian.org>
> Reported-and-tested-by: Usama Arif <usamaarif642@...il.com>
> Suggested-by: Ard Biesheuvel <ardb@...nel.org>
> Signed-off-by: Dave Young <dyoung@...hat.com>
>
> diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
> index 846bf49f2508..553f330198f2 100644
> --- a/arch/x86/platform/efi/quirks.c
> +++ b/arch/x86/platform/efi/quirks.c
> @@ -561,6 +561,11 @@ int __init efi_reuse_config(u64 tables, int nr_tables)
>
>                 if (!efi_guidcmp(guid, SMBIOS_TABLE_GUID))
>                         ((efi_config_table_64_t *)p)->table = data->smbios;
> +
> +               /* Do not bother to play with mem attr table across kexec */
> +               if (!efi_guidcmp(guid, EFI_MEMORY_ATTRIBUTES_TABLE_GUID))
> +                       ((efi_config_table_64_t *)p)->table = EFI_INVALID_TABLE_ADDR;
> +
>                 p += sz;
>         }
>         early_memunmap(tablep, nr_tables * sz);
>

Thanks. I've queued this up now.