[PATCH v2 2/3] efi_loader: Prevent dereference of uninitialised variable

[Ilias Apalodimas]

Thanks Andrew

On Wed, 2 Jul 2025 at 13:01, Andrew Goodbody <andrew.goodbody at linaro.org> wrote:
>
> If phandler is returned as NULL from efi_search_protocol then
> protocol_interface is never assigned to. Instead return
> EFI_UNSUPPORTED as per the spec.
>
> This issue found by Smatch.
>
> Also eliminate the use of the variable protocol_interface as it is not
> needed.
>
> Signed-off-by: Andrew Goodbody <andrew.goodbody at linaro.org>
> ---

Reviewed-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>


>  lib/efi_loader/efi_http.c | 9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/lib/efi_loader/efi_http.c b/lib/efi_loader/efi_http.c
> index 189317fe2d2..9a0f2675132 100644
> --- a/lib/efi_loader/efi_http.c
> +++ b/lib/efi_loader/efi_http.c
> @@ -453,7 +453,6 @@ static efi_status_t EFIAPI efi_http_service_binding_destroy_child(
>         efi_status_t ret = EFI_SUCCESS;
>         struct efi_http_instance *http_instance;
>         struct efi_handler *phandler;
> -       void *protocol_interface;
>
>         if (num_instances == 0)
>                 return EFI_EXIT(EFI_NOT_FOUND);
> @@ -463,18 +462,18 @@ static efi_status_t EFIAPI efi_http_service_binding_destroy_child(
>
>         efi_search_protocol(child_handle, &efi_http_guid, &phandler);
>
> -       if (phandler)
> -               protocol_interface = phandler->protocol_interface;
> +       if (!phandler)
> +               return EFI_EXIT(EFI_UNSUPPORTED);
>
>         ret = efi_delete_handle(child_handle);
>         if (ret != EFI_SUCCESS)
>                 return EFI_EXIT(ret);
>
> -       http_instance = (struct efi_http_instance *)protocol_interface;
> +       http_instance = phandler->protocol_interface;
>         efi_free_pool(http_instance->http_load_addr);
>         http_instance->http_load_addr = NULL;
>
> -       free(protocol_interface);
> +       free(phandler->protocol_interface);
>
>         num_instances--;
>
>
> --
> 2.39.5
>