efi_loader: avoid NULL dereference in efi_get_memory_map()

We should only dereference parameter memory_map_size after checking that
it is valid.

Fixes: 8e835554b36b ("efi_loader: check parameters of GetMemoryMap")
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
1 file changed