[PATCH 1/3] EFI: Populate descriptor_count value only when image_info_size is not zero

[Heinrich Schuchardt]

On 5/31/22 09:15, Sughosh Ganu wrote:
> The GetImageInfo function of the Firmware Mangement Protocol(FMP) gets
> called initially to query the size of the image descriptor array that
> would have to be allocated. During this call, the rest of the function
> arguments, specifically pointers might be passed as NULL. Do not
> populate the descriptor_count value before it is known that the call
> to GetImageInfo has been made with the allocated buffer for the image
> descriptors.
>
> Signed-off-by: Sughosh Ganu <sughosh.ganu at linaro.org>

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

> ---
>   lib/efi_loader/efi_firmware.c | 5 ++---
>   1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/lib/efi_loader/efi_firmware.c b/lib/efi_loader/efi_firmware.c
> index 27953fe769..6290ca0190 100644
> --- a/lib/efi_loader/efi_firmware.c
> +++ b/lib/efi_loader/efi_firmware.c
> @@ -130,9 +130,6 @@ static efi_status_t efi_fill_image_desc_array(
>   	struct efi_fw_image *fw_array;
>   	int i;
>
> -	fw_array = update_info.images;
> -	*descriptor_count = num_image_type_guids;
> -
>   	total_size = sizeof(*image_info) * num_image_type_guids;
>
>   	if (*image_info_size < total_size) {
> @@ -142,6 +139,8 @@ static efi_status_t efi_fill_image_desc_array(
>   	}
>   	*image_info_size = total_size;
>
> +	fw_array = update_info.images;
> +	*descriptor_count = num_image_type_guids;
>   	*descriptor_version = EFI_FIRMWARE_IMAGE_DESCRIPTOR_VERSION;
>   	*descriptor_size = sizeof(*image_info);
>   	*package_version = 0xffffffff; /* not supported */