From v1.70.0 until the serve Provider refactor (f425f8d46), an FTP server started
through the rc serve/start API with a per-server proxyOpt.AuthProxy
decided whether to enable proxy authentication by checking the
process-global proxy.Opt.AuthProxy instead of the supplied
proxyOpt.AuthProxy. In the normal rc case the global is empty, so the
auth proxy was silently ignored and the server fell back to its
fixed-backend mode, whose default account accepts user "anonymous" with
any password - a complete authentication bypass.
The Provider refactor fixed this incidentally by building the provider
from the proxyOpt passed to the constructor. This adds a regression test
so the per-server option cannot silently stop working again.
Nick Craig-Wood
212178eea1