Add regression test for CVE-2022-1183

If sslyze is available in PATH, run it in a loop as part of the "doth"
system test.

bin/tests/system/doth/tests_sslyze.py

@@ -0,0 +1,57 @@
+#!/usr/bin/python3
+
+# Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+#
+# SPDX-License-Identifier: MPL-2.0
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0.  If a copy of the MPL was not distributed with this
+# file, you can obtain one at https://mozilla.org/MPL/2.0/.
+#
+# See the COPYRIGHT file distributed with this work for additional
+# information regarding copyright ownership.
+
+import os
+import pathlib
+import subprocess
+
+import pytest
+
+
+def is_pid_alive(pid):
+    try:
+        os.kill(pid, 0)
+        return True
+    except OSError:
+        return False
+
+
+def test_sslyze_doh(sslyze_executable, named_httpsport):
+    # Determine the PID of ns1.
+    with open(pathlib.Path("ns1", "named.pid"), encoding="utf-8") as pidfile:
+        pid = int(pidfile.read())
+
+    # Ensure ns1 is alive before starting the loop below to avoid reporting
+    # false positives.
+    if not is_pid_alive(pid):
+        pytest.skip(f"ns1 (PID: {pid}) is not running")
+
+    # Run sslyze on ns1 in a loop with a limit of 30 iterations.  Interrupt the
+    # test as soon as ns1 is determined to not be running any more.  Log sslyze
+    # output.
+    sslyze_args = [sslyze_executable, f"10.53.0.1:{named_httpsport}"]
+    for i in range(0, 30):
+        log_file = f"sslyze.log.doh.ns1.{named_httpsport}.{i + 1}"
+        with open(log_file, "wb") as sslyze_log:
+            # Run sslyze, logging stdout+stderr.  Ignore the exit code since
+            # sslyze is only used for triggering crashes here rather than
+            # actual TLS analysis.
+            subprocess.run(
+                sslyze_args,
+                stdout=sslyze_log,
+                stderr=subprocess.STDOUT,
+                timeout=30,
+                check=False,
+            )
+            # Ensure ns1 is still alive after each sslyze run.
+            assert is_pid_alive(pid), f"ns1 (PID: {pid}) exited prematurely"