Fix hanging forever if rsock doesnt connect

.github/workflows/verify.yml

@@ -39,6 +39,8 @@ jobs:
           - '3.2'
         os:
           - ubuntu-20.04
+          - windows-2019
+          - macos-11
           - ubuntu-latest
         exclude:
           - { os: ubuntu-latest, ruby: '2.7' }
@@ -52,7 +54,7 @@ jobs:
     name: ${{ matrix.os }} - Ruby ${{ matrix.ruby }} - ${{ matrix.test_cmd }}
     steps:
       - name: Checkout code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
 
       - name: Setup Ruby
         uses: ruby/setup-ruby@v1

lib/rex/socket.rb

@@ -672,20 +672,27 @@ def self.ipv6_mac(intf)
   #       is no concurrent use of the same locals and this is safe.
   def self.tcp_socket_pair
     lsock   = nil
+    last_child_error = nil
+    accept_timeout = 10
     rsock   = nil
     laddr   = '127.0.0.1'
     lport   = 0
     threads = []
     mutex   = ::Mutex.new
 
-    threads << Rex::ThreadFactory.spawn('TcpSocketPair', false) {
+    threads << Rex::ThreadFactory.spawn('TcpSocketPair', false) do
       server = nil
-      mutex.synchronize {
-        threads << Rex::ThreadFactory.spawn('TcpSocketPairClient', false) {
-          mutex.synchronize {
-            rsock = ::TCPSocket.new( laddr, lport )
-          }
-        }
+      mutex.synchronize do
+        threads << Rex::ThreadFactory.spawn('TcpSocketPairClient', false) do
+          mutex.synchronize do
+            begin
+              rsock = ::TCPSocket.new( laddr, lport )
+            rescue => e
+              last_child_error = "#{e.class} - #{e.message}"
+              raise
+            end
+          end
+        end
         server = ::TCPServer.new(laddr, 0)
         if (server.getsockname =~ /127\.0\.0\.1:/)
           # JRuby ridiculousness
@@ -697,12 +704,23 @@ def self.tcp_socket_pair
           # sockaddr
           lport, caddr = ::Socket.unpack_sockaddr_in( server.getsockname )
         end
-      }
-      lsock, _ = server.accept
+      end
+
+      readable, _writable, _errors = ::IO.select([server], nil, nil, accept_timeout)
+      if readable && readable.any?
+        lsock, _ = server.accept
+      else
+        raise RuntimeError, "rsock didn't connect in #{accept_timeout} seconds"
+      end
+
       server.close
-    }
+    end
 
-    threads.each { |t| t.join }
+    threads.each do |thread|
+      thread.join
+    rescue => e
+      raise "Error #{e} - last child error: #{last_child_error}"
+    end
 
     return [lsock, rsock]
   end

spec/rex/socket_spec.rb

@@ -4,6 +4,44 @@
 
 RSpec.describe Rex::Socket do
 
+  describe '.tcp_socket_pair' do
+    let(:mock_thread_factory) do
+      double :mock_thread_factory
+    end
+
+    before(:each) do
+      stub_const('Rex::ThreadFactory', mock_thread_factory)
+      # Fallback implementation from https://github.com/rapid7/metasploit-framework/blob/30e66c43a4932df922d7f1d986fb98387bd0ab1a/lib/rex/thread_factory.rb#L27-L37
+      allow(mock_thread_factory).to receive(:spawn) do |name, crit, *args, &block|
+        if block
+          t = ::Thread.new(*args){ |*args_copy| block.call(*args_copy) }
+        else
+          t = ::Thread.new(*args)
+        end
+        t[:tm_name] = name
+        t[:tm_crit] = crit
+        t[:tm_time] = ::Time.now
+        t[:tm_call] = caller
+        t
+      end
+    end
+
+    it 'creates two socket pairs' do
+      lsock, rsock = described_class.tcp_socket_pair
+      lsock.extend(Rex::IO::Stream)
+      rsock.extend(Rex::IO::Stream)
+
+      expect(lsock.closed?).to be(false)
+      expect(rsock.closed?).to be(false)
+
+      lsock.close
+      rsock.close
+
+      expect(lsock.closed?).to be(true)
+      expect(rsock.closed?).to be(true)
+    end
+  end
+
   describe '.addr_itoa' do
 
     context 'with explicit v6' do