Re: [PATCH] efi/x86: Fix the deletion of variables in mixed mode

From: Ard Biesheuvel <ardb@kernel.org>
To: Gary Lin <glin@suse.com>
Cc: linux-efi <linux-efi@vger.kernel.org>,
	Ingo Molnar <mingo@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH] efi/x86: Fix the deletion of variables in mixed mode
Date: Wed, 8 Apr 2020 10:20:50 +0200	[thread overview]
Message-ID: <CAMj1kXFwZiirOQ2gu2CcScdb3H782vpL2qT6ijqTfdQ8-cKSgw@mail.gmail.com> (raw)
In-Reply-To: <20200408081606.1504-1-glin@suse.com>

On Wed, 8 Apr 2020 at 10:18, Gary Lin <glin@suse.com> wrote:
>
> efi_thunk_set_variable() treated the NULL "data" pointer as an invalid
> parameter, and this broke the deletion of variables in mixed mode.
> This commit fixes the check of data so that the userspace program can
> delete a variable in mixed mode.
>
> Fixes: 8319e9d5ad98ffcc ("efi/x86: Handle by-ref arguments covering multiple pages in mixed mode")
> Cc: linux-efi@vger.kernel.org
> Cc: Ard Biesheuvel <ardb@kernel.org>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Signed-off-by: Gary Lin <glin@suse.com>

Thanks Gary.

I'll queue this in efi/urgent.

> ---
>  arch/x86/platform/efi/efi_64.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
> index 211bb9358b73..e0e2e8136cf5 100644
> --- a/arch/x86/platform/efi/efi_64.c
> +++ b/arch/x86/platform/efi/efi_64.c
> @@ -638,7 +638,7 @@ efi_thunk_set_variable(efi_char16_t *name, efi_guid_t *vendor,
>         phys_vendor = virt_to_phys_or_null(vnd);
>         phys_data = virt_to_phys_or_null_size(data, data_size);
>
> -       if (!phys_name || !phys_data)
> +       if (!phys_name || (data && !phys_data))
>                 status = EFI_INVALID_PARAMETER;
>         else
>                 status = efi_thunk(set_variable, phys_name, phys_vendor,
> @@ -669,7 +669,7 @@ efi_thunk_set_variable_nonblocking(efi_char16_t *name, efi_guid_t *vendor,
>         phys_vendor = virt_to_phys_or_null(vnd);
>         phys_data = virt_to_phys_or_null_size(data, data_size);
>
> -       if (!phys_name || !phys_data)
> +       if (!phys_name || (data && !phys_data))
>                 status = EFI_INVALID_PARAMETER;
>         else
>                 status = efi_thunk(set_variable, phys_name, phys_vendor,
> --
> 2.25.1
>