[#3605] Integrate a new fuzzing solution in Kea

The solution is based on clusterfuzzlite, libfuzzer, and oss-fuzz
technologies.

- Add the .clusterfuzzlite directory.
- Add the fuzz CI stage and fuzzing CI jobs.
- Add the fuzzing targets in the fuzz directory.
- Document fuzzing in doxygen.

1 files changed, 72 insertions, 0 deletions

diff --git a/fuzz/fuzz_config_kea_dhcp6.cc b/fuzz/fuzz_config_kea_dhcp6.cc
new file mode 100644
index 0000000000..9e11552c8f
--- /dev/null
+++ b/fuzz/fuzz_config_kea_dhcp6.cc
@@ -0,0 +1,72 @@
+// Copyright (C) 2024 Internet Systems Consortium, Inc. ("ISC")
+//
+// 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 http://mozilla.org/MPL/2.0/.
+
+#include <config.h>
+
+#include <fuzz.h>
+
+#include <cc/command_interpreter.h>
+#include <cc/user_context.h>
+#include <dhcp6/ctrl_dhcp6_srv.h>
+#include <dhcp6/json_config_parser.h>
+#include <dhcp6/parser_context.h>
+
+#include <cassert>
+#include <util/filesystem.h>
+#include <string>
+
+using namespace isc;
+using namespace isc::config;
+using namespace isc::data;
+using namespace isc::dhcp;
+using namespace isc::process;
+using namespace std;
+
+namespace {
+
+static pid_t const PID(getpid());
+static string const PID_STR(to_string(PID));
+static string const KEA_DHCP6_CONF(KEA_FUZZ_DIR + "/kea-dhcp6-" + PID_STR + ".conf");
+
+}  // namespace
+
+extern "C" {
+
+int
+LLVMFuzzerInitialize() {
+    static bool initialized(DoInitialization());
+    assert(initialized);
+
+    return 0;
+}
+
+int
+LLVMFuzzerTearDown() {
+    try {
+        remove(KEA_DHCP6_CONF.c_str());
+    } catch (...) {
+    }
+    return 0;
+}
+
+int
+LLVMFuzzerTestOneInput(uint8_t const* data, size_t size) {
+    // Create the config file.
+    string const string_config(reinterpret_cast<char const*>(data), size);
+    writeToFile(KEA_DHCP6_CONF, string_config);
+
+    // Configure the server.
+    ControlledDhcpv6Srv server;
+    try {
+        server.init(KEA_DHCP6_CONF);
+    } catch (BadValue const&) {
+    } catch (Dhcp6ParseError const&) {
+    }
+
+    return 0;
+}
+
+}  // extern "C"