[U-Boot] [PATCH] efi_loader: variable: attributes may not be changed if a variable exists

[Heinrich Schuchardt <xypron.glpk@gmx.de>]

On 5/14/19 6:57 AM, AKASHI Takahiro wrote:
> If a variable already exists, efi_set_variable() should not change
> the variable's attributes. This patch enforces it.

This behavior is mandated by UEFI spec 2.7.

Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

>
> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> ---
>   lib/efi_loader/efi_variable.c | 9 +++++++++
>   1 file changed, 9 insertions(+)
>
> diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c
> index 37728c3c165d..c4f3a5d2743d 100644
> --- a/lib/efi_loader/efi_variable.c
> +++ b/lib/efi_loader/efi_variable.c
> @@ -450,6 +450,15 @@ efi_status_t EFIAPI efi_set_variable(u16 *variable_name,
>   			ret = EFI_WRITE_PROTECTED;
>   			goto out;
>   		}
> +
> +		/*
> +		 * attributes won't be changed
> +		 * TODO: take care of APPEND_WRITE once supported
> +		 */
> +		if (attr != attributes) {
> +			ret = EFI_INVALID_PARAMETER;
> +			goto out;
> +		}
>   	}
>
>   	val = malloc(2 * data_size + strlen("{ro,run,boot}(blob)") + 1);
>