Fix failing ldap server tests

[adfoster-r7]

Fix failing ldap server tests introduced by #18678 - by no longer creating real TCP or UDP sockets

Verification

• Ensure CI passes

Ensure tests pass locally when port 40000 is already bound:

$ ncat -lnvp 40000
Ncat: Version 7.94 ( https://nmap.org/ncat )
Ncat: Listening on [::]:40000
Ncat: Listening on 0.0.0.0:40000

Before:

$ bundle exec rspec ./spec/lib/rex/proto/ldap/server_spec.rb
...

Randomized with seed 44755
Rex::Proto::LDAP::Server ..F...FF.F...

  1) Rex::Proto::LDAP::Server#stop stops the server when running
     Failure/Error: @tcp_sock = Rex::Socket::TcpServer.create(sock_options)
     
     Rex::BindFailed:
       The address is already in use or unavailable: (0.0.0.0:40000).
 

After:

$ bundle exec rspec ./spec/lib/rex/proto/ldap/server_spec.rb
...
Finished in 0.04572 seconds (files took 6.97 seconds to load)
13 examples, 0 failures

[adfoster-r7]

It's not possible to use instance_double Rex::Socket::TcpServer here for an InstanceVerifyingDouble - as behind the scenes in result of Rex::Socket::TcpServer.create(...) is a ::Socket instance that's been monkey patched with modules like Rex::Socket::TcpServer etc, which makes it awkward to use instance_double here:

[5] pry(#<Rex::Proto::LDAP::Server>)> whereami

From: /Users/user/Documents/code/metasploit-framework/lib/rex/proto/ldap/server.rb:102 Rex::Proto::LDAP::Server#start:

     97:           end
     98: 
     99:           if serve_tcp
    100:             @tcp_sock = Rex::Socket::TcpServer.create(sock_options)
    101:             require 'pry-byebug'; binding.pry
 => 102:             tcp_sock.on_client_connect_proc = proc do |cli|
    103:               on_client_connect(cli)
    104:             end
    105:             tcp_sock.on_client_data_proc = proc do |cli|
    106:               on_client_data(cli)
    107:             end

[6] pry(#<Rex::Proto::LDAP::Server>)> @tcp_sock.class
=> Socket
[7] pry(#<Rex::Proto::LDAP::Server>)> @tcp_sock.singleton_class.included_modules
=> [Rex::Socket::TcpServer,
 Rex::IO::StreamServer,
 Rex::Socket,
 Net::BER::BERParser,
  ...]

[JustAnda7]

If possible can you explain why that was happening?

[adfoster-r7]

For unit tests we generally want to avoid creating real servers etc. So I've gone with mocking the Rex::Socket::TcpServer.create(...) call.

The rex-socket implementation uses Ruby's API for creating a socket here:

https://github.com/rapid7/rex-socket/blob/fba62cdf31e2804b91667b34759a31da823bbeb7/lib/rex/socket/tcp_server.rb#L36-L40

And here:

https://github.com/rapid7/rex-socket/blob/fba62cdf31e2804b91667b34759a31da823bbeb7/lib/rex/socket/comm/local.rb#L170-L175

Then adds additional methods and state onto the socket instance with .extend ... here:

https://github.com/rapid7/rex-socket/blob/fba62cdf31e2804b91667b34759a31da823bbeb7/lib/rex/socket/tcp_server.rb#L54

Let me know if I haven't answered your question 😄

[adfoster-r7]

cc @JustAnda7 - does this look okay to you as fix? 🤞

[JustAnda7]

Thanks for correcting my mistakes.

[dwelch-r7]

Release Notes

Fixes failing ldap server tests