Introduce JDK8+ compatibility layer

ALPN support merged in JDK9 and will eventually be backported into JDK8. However, not every consumer of JSS will necessarily upgrade to a newer JDK8 version. While support has landed upstream, Fedora 32 and Fedora 33 haven't yet seen a backport yet. This likely means that RHEL also won't see a backport. Introduce a small reflection-based compatibility layer to see if the class supports ALPN and if so, use the value from it. Signed-off-by: Alexander Scheel <[email protected]>
dogtagpki · Oct 6, 2020 · 2b9b4e4 · 2b9b4e4
1 parent b3fbd05
commit 2b9b4e4
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diff --git a/org/mozilla/jss/ssl/javax/JSSParameters.java b/org/mozilla/jss/ssl/javax/JSSParameters.java
@@ -3,6 +3,7 @@
 import javax.net.ssl.*;
 import java.util.*;
 
+import org.mozilla.jss.util.JDKCompat;
 import org.mozilla.jss.ssl.*;
 
 /**
@@ -56,7 +57,7 @@ public JSSParameters(SSLParameters downcast) {
             setNeedClientAuth(downcast.getNeedClientAuth());
         }
 
-        String[] alpn = downcast.getApplicationProtocols(downcast);
+        String[] alpn = JDKCompat.SSLParametersHelper.getApplicationProtocols(downcast);
         if (alpn != null) {
             setApplicationProtocols(alpn);
         }

diff --git a/org/mozilla/jss/util/JDKCompat.java b/org/mozilla/jss/util/JDKCompat.java
@@ -0,0 +1,22 @@
+
+package org.mozilla.jss.util;
+
+import java.lang.reflect.Method;
+
+import javax.net.ssl.SSLParameters;
+
+public class JDKCompat {
+    public static class SSLParametersHelper {
+        public static String[] getApplicationProtocols(SSLParameters inst) {
+            try {
+                Method getter = inst.getClass().getMethod("getApplicationProtocols");
+                Object result = getter.invoke(inst);
+                return (String[]) result;
+            } catch (NoSuchMethodException nsme) {
+                return null;
+            } catch (Throwable t) {
+                throw new RuntimeException(t.getMessage(), t);
+            }
+        }
+    }
+}