Your assessment of the situation is commendably clear and correct.

The usual way to deal with situations like this is to have a child process which runs suid from a root owned file, and is carefully constructed to only assert high privilege where needed. A typical example is a device driver which asserts privilege only to change state, and serializes inputs by connection, preventing interactions.

XS or Inline::C are very likely to be useful in obtaining that. Neither is portable while there exists an OS which officially considers any but their own programming to be pure poison.

After Compline,
Zaxo