[PATCH] efi_loader: check efi_get_variable_int return value

[Heinrich Schuchardt]

On 1/22/24 08:26, Masahisa Kojima wrote:
> efi_get_variable_int() may fail, the buffer should be
> cleared before using it.
>
> Signed-off-by: Masahisa Kojima <masahisa.kojima at linaro.org>
> Addresses-Coverity-ID: 478333 ("Error handling issues")
> ---
>   lib/efi_loader/efi_firmware.c | 8 ++++----
>   1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/lib/efi_loader/efi_firmware.c b/lib/efi_loader/efi_firmware.c
> index 9fd13297a6..fb83fa8113 100644
> --- a/lib/efi_loader/efi_firmware.c
> +++ b/lib/efi_loader/efi_firmware.c
> @@ -407,11 +407,11 @@ efi_status_t efi_firmware_set_fmp_state_var(struct fmp_state *state, u8 image_in
>   	/*
>   	 * GetVariable may fail, EFI_NOT_FOUND is returned if FmpState
>   	 * variable has not been set yet.
> -	 * Ignore the error here since the correct FmpState variable
> -	 * is set later.
>   	 */
> -	efi_get_variable_int(varname, image_type_id, NULL, &size, var_state,
> -			     NULL);
> +	ret = efi_get_variable_int(varname, image_type_id, NULL, &size,
> +				   var_state, NULL);
> +	if (ret != EFI_SUCCESS)
> +		memset(var_state, 0, num_banks * sizeof(*var_state));

Hello Masahisa,

We allocate var_state with calloc(). So it is cleared before we call
GetVariable(). Do we have an implementation of GetVariable() that would
fill it with data before returning an error code?

Best regards

Heinrich

>
>   	/*
>   	 * Only the fw_version is set here.