efi/libstub: Zero initialize heap allocated struct screen_info

commit ee8b8f5 upstream.

After calling uefi interface allocate_pool to apply for memory, we
should clear 0 to prevent the possibility of using random values.

Signed-off-by: Qiang Ma <[email protected]>
Cc: <[email protected]> # v6.6+
Fixes: 732ea9d ("efi: libstub: Move screen_info handling to common code")
Signed-off-by: Ard Biesheuvel <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

drivers/firmware/efi/libstub/screen_info.c

@@ -32,6 +32,8 @@ struct screen_info *__alloc_screen_info(void)
 	if (status != EFI_SUCCESS)
 		return NULL;
 
+	memset(si, 0, sizeof(*si));
+
 	status = efi_bs_call(install_configuration_table,
 			     &screen_info_guid, si);
 	if (status == EFI_SUCCESS)