change port bind and add a unittest (#10208)

.changes/unreleased/Security-20240522-094540.yaml

@@ -0,0 +1,6 @@
+kind: Security
+body: Explicitly bind to localhost in docs serve
+time: 2024-05-22T09:45:40.748185-04:00
+custom:
+  Author: ChenyuLInx michelleark
+  Issue: "10209"

core/dbt/task/docs/serve.py

@@ -20,7 +20,7 @@ def run(self):
         if self.args.browser:
             webbrowser.open_new_tab(f"http://localhost:{port}")
 
-        with socketserver.TCPServer(("", port), SimpleHTTPRequestHandler) as httpd:
+        with socketserver.TCPServer(("127.0.0.1", port), SimpleHTTPRequestHandler) as httpd:
             click.echo(f"Serving docs at {port}")
             click.echo(f"To access from your browser, navigate to: http://localhost:{port}")
             click.echo("\n\n")

tests/unit/task/docs/test_serve.py

@@ -0,0 +1,23 @@
+from http.server import SimpleHTTPRequestHandler
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from dbt.task.docs.serve import ServeTask
+
+
+@pytest.fixture
+def serve_task():
+    # Set up
+    task = ServeTask(config=MagicMock(), args=MagicMock())
+    task.config.project_target_path = "."
+    task.args.port = 8000
+    return task
+
+
+def test_serve_bind_to_127(serve_task):
+    serve_task.args.browser = False
+    with patch("dbt.task.docs.serve.socketserver.TCPServer") as patched_TCPServer:
+        patched_TCPServer.return_value = MagicMock()
+        serve_task.run()
+        patched_TCPServer.assert_called_once_with(("127.0.0.1", 8000), SimpleHTTPRequestHandler)