[JEP-xxx] introduce FIPS property

Introduces the code that core and plugins can use to switch behaviour
based on FIPS-140 requirements

core/src/main/java/jenkins/security/FIPS140.java

@@ -0,0 +1,60 @@
+/*
+ * The MIT License
+ *
+ * Copyright (c) 2023, Cloudbees, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package jenkins.security;
+
+import java.util.logging.Level;
+import java.util.logging.Logger;
+import jenkins.util.SystemProperties;
+
+/**
+ * Utilities to help code change behaviour when it is desired to run in a FIPS-140 enabled environment.
+ * The environment (host, JVM and servlet container), must be suitably configured which is outside the scope of the Jenkins project.
+ * @see <a href="https://csrc.nist.gov/pubs/fips/140-2/upd2/final">FIPS-140-2</a>
+ * @see <a href="https://github.com/jenkinsci/jep/pull/398/files">JEP-XXXX</a>
+ * @since TODO
+ */
+public class FIPS140 {
+
+    private static final Logger LOGGER = Logger.getLogger(FIPS140.class.getName());
+
+    private static final boolean FIPS_COMPLIANCE_MODE = SystemProperties.getBoolean(FIPS140.class.getName() + ".COMPLIANCE");
+
+    static {
+        if (useCompliantAlgorithms()) {
+            LOGGER.log(Level.CONFIG, "System has been asked to run in FIPS-140 compliant mode");
+        }
+    }
+
+    /**
+     * Provide a hint that the system should strive to be compliant with <a href="https://csrc.nist.gov/pubs/fips/140-2/upd2/final">FIPS-140-2</a>.
+     * This can be used by code that needs to make choices at runtime whether to disable some optional behaviour that is not compliant with FIPS-140,
+     * or to switch to a compliant (yet less secure) alternative.
+     * If this returns {@code true} it does not mean that the instance is compliant, it merely acts as a hint.
+     * @return {@code true} iff the system should prefer compliance with FIPS-140-2 over compatibility with existing data or alternative non approved algorithms.
+     */
+    public static boolean useCompliantAlgorithms() {
+        return FIPS_COMPLIANCE_MODE;
+    }
+
+}