[U-Boot] [RFC] efi_loader: memory leak in bootefi

[Heinrich Schuchardt]

Hello Alex,

in bootefi.c do_bootefi_exec we build the efi_obj_list. This includes
allocation of memory for some handlers (e.g. in efi_gop_register).

After returning from the efi appliation we have no clean up code to
release these objects.

We do not remove the list elements from efi_obj_list.

Furthermore we rely on a lot of static initializations e.g. for
protocols. We know that this data may be changed by the application but
we do not care to restore the original state.

So if an application registers protocols and exits without unregistering
we will offer invalid function pointers to the next efi application to
be started.

I suggest the following:

In structure struct efi_object we add a function pointer to a clean-up
function which takes as only argument the efi_object:

struct efi_object {
        struct list_head link;
        struct efi_handler protocols[4];
	void (*cleanup)(struct efi_object *obj);
        void *handle;
};

A clean up function may look like this:
void efi_gop_cleanup(struct efi_object *obj) {
	free(obj);
}

When returning from the EFI application we would work our way from the
tail to the head of the object list:

while (list is not empty) {
	Remove last object from list.
	Call cleanup function of removed object.
}

We should get rid of the static structures loaded_image_info_obj
and boot_efi_obj. Let's use register functions with calloc here too.

Would you agree to this design?

Best regards

Heinrich