JNI/JSSE: wrap wolfSSL_DisableExtendedMasterSecret(), add support for System property jdk.tls.useExtendedMasterSecret

Author: cconlon

README.md

@@ -534,6 +534,11 @@ are enabled in different ways depending on the JDK implementation. For
 Oracle/OpenJDK and variants, this System property enables session tickets and
 was added in Java 13. Should be set to "true" to enable.
 
+**jdk.tls.useExtendedMasterSecret (boolean)** - Can be used to enable or
+disable the use of the Extended Master Secret (EMS) extension. This extension
+is enabled by default, unless explicitly disabled by setting this property to
+false.
+
 **wolfjsse.autoSNI (boolean)** - Controls automatic Server Name Indication (SNI)
 extension setting based on hostname or peer address. When set to "true", enables
 legacy behavior where SNI is automatically configured from hostname/peer information

native/com_wolfssl_WolfSSL.c

@@ -1995,6 +1995,19 @@ JNIEXPORT jint JNICALL Java_com_wolfssl_WolfSSL_isEnabledPKCallbacks
 #endif
 }
 
+JNIEXPORT jint JNICALL Java_com_wolfssl_WolfSSL_isEnabledTLSExtendedMasterSecret
+  (JNIEnv* jenv, jclass jcl)
+{
+    (void)jenv;
+    (void)jcl;
+
+#if defined(HAVE_EXTENDED_MASTER) && !defined(NO_WOLFSSL_CLIENT)
+    return 1;
+#else
+    return 0;
+#endif
+}
+
 JNIEXPORT jobjectArray JNICALL Java_com_wolfssl_WolfSSL_getProtocols
   (JNIEnv* jenv, jclass jcl)
 {

native/com_wolfssl_WolfSSL.h

@@ -5765,6 +5765,26 @@ JNIEXPORT jint JNICALL Java_com_wolfssl_WolfSSLSession_useSupportedCurve
 #endif
 }
 
+JNIEXPORT jint JNICALL Java_com_wolfssl_WolfSSLSession_disableExtendedMasterSecret
+  (JNIEnv* jenv, jobject jcl, jlong sslPtr)
+{
+#if defined(HAVE_EXTENDED_MASTER) && !defined(NO_WOLFSSL_CLIENT)
+    int ret = 0;
+    WOLFSSL* ssl = (WOLFSSL*)(uintptr_t)sslPtr;
+    (void)jcl;
+
+    /* Checks ssl for null internally */
+    ret = wolfSSL_DisableExtendedMasterSecret(ssl);
+
+    return (jint)ret;
+#else
+    (void)jenv;
+    (void)jcl;
+    (void)sslPtr;
+    return (jint)NOT_COMPILED_IN;
+#endif
+}
+
 JNIEXPORT jint JNICALL Java_com_wolfssl_WolfSSLSession_hasTicket
   (JNIEnv* jenv, jobject jcl, jlong sessionPtr)
 {

native/com_wolfssl_WolfSSLSession.c

@@ -1662,6 +1662,14 @@ public static int cryptoCbUnRegisterDevice(int devId) {
      */
     public static native int isEnabledPKCallbacks();
 
+    /**
+     * Checks if TLS Extended Master Secret support has been compiled into
+     * native wolfSSL library.
+     *
+     * @return 1 if available, 0 if not compiled in.
+     */
+    public static native int isEnabledTLSExtendedMasterSecret();
+
     /**
      * Checks which protocols where built into wolfSSL
      *

native/com_wolfssl_WolfSSLSession.h

@@ -418,6 +418,7 @@ private native int setTlsHmacInner(long ssl, byte[] inner, long sz,
     private native int rehandshake(long ssl);
     private native int set1SigAlgsList(long ssl, String list);
     private native int useSupportedCurve(long ssl, int name);
+    private native int disableExtendedMasterSecret(long ssl);
     private native int hasTicket(long session);
     private native int interruptBlockedIO(long ssl);
     private native int getThreadsBlockedInPoll(long ssl);
@@ -2241,6 +2242,23 @@ public int useSupportedCurves(String[] curveNames)
         return ret;
     }
 
+    /**
+     * Disable TLS Extended Master Secret usage.
+     *
+     * @return <code>WolfSSL.SSL_SUCCESS</code> on success, otherwise
+     *         negative on error.
+     * @throws IllegalStateException WolfSSLSession has been freed
+     */
+    public int disableExtendedMasterSecret()
+        throws IllegalStateException {
+
+        confirmObjectIsActive();
+
+        synchronized (sslLock) {
+            return disableExtendedMasterSecret(this.sslPtr);
+        }
+    }
+
     /* ---------------- Nonblocking DTLS helper functions  -------------- */
 
     /**

src/java/com/wolfssl/WolfSSL.java

@@ -1176,6 +1176,38 @@ else if (ret == WolfSSL.NOT_COMPILED_IN) {
         }
     }
 
+    private void setLocalExtendedMasterSecret() {
+        /* Native wolfSSL enables TLS Extended Master Secret by default.
+         * Check the Java System property (jdk.tls.useExtendedMasterSecret)
+         * to see if the user has explicitly disabled it. */
+        int ret;
+        boolean useEMS = WolfSSLUtil.useExtendedMasterSecret();
+
+        if (!useEMS) {
+            ret = this.ssl.disableExtendedMasterSecret();
+            if (ret == WolfSSL.SSL_SUCCESS) {
+                WolfSSLDebug.log(getClass(), WolfSSLDebug.INFO,
+                    "TLS Extended Master Secret disabled due to " +
+                    "jdk.tls.useExtendedMasterSecret System property");
+            }
+            else {
+                WolfSSLDebug.log(getClass(), WolfSSLDebug.INFO,
+                    "Failed to disable TLS Extended Master Secret, " +
+                    "ret = " + ret);
+            }
+        }
+        else {
+            if (WolfSSL.isEnabledTLSExtendedMasterSecret() == 1) {
+                WolfSSLDebug.log(getClass(), WolfSSLDebug.INFO,
+                    "using TLS Extended Master Secret");
+            }
+            else {
+                WolfSSLDebug.log(getClass(), WolfSSLDebug.INFO,
+                    "not using TLS Extended Master Secret, not compiled in");
+            }
+        }
+    }
+
     private void setLocalParams(SSLSocket socket, SSLEngine engine)
         throws SSLException {
 
@@ -1192,6 +1224,7 @@ private void setLocalParams(SSLSocket socket, SSLEngine engine)
         this.setLocalSigAlgorithms();
         this.setLocalSupportedCurves();
         this.setLocalMaximumPacketSize();
+        this.setLocalExtendedMasterSecret();
     }
 
     /**

src/java/com/wolfssl/WolfSSLSession.java

@@ -286,6 +286,35 @@ protected static boolean sessionCacheDisabled() {
         return false;
     }
 
+    /**
+     * Return if TLS Extended Master Secret support has been enabled or
+     * disabled via the following System property:
+     *
+     * jdk.tls.useExtendedMasterSecret
+     *
+     * If property is not set (null) or an empty string, we default to
+     * leaving TLS Extended Master Secret enabled.
+     *
+     * @return true if enabled, otherwise false
+     */
+    protected static boolean useExtendedMasterSecret() {
+
+        String useEMS =
+            System.getProperty("jdk.tls.useExtendedMasterSecret");
+
+        /* Native wolfSSL defaults to having extended master secret support
+         * enabled. Do the same here if property not set or empty. */
+        if (useEMS == null || useEMS.isEmpty()) {
+            return true;
+        }
+
+        if (useEMS.equalsIgnoreCase("false")) {
+            return false;
+        }
+
+        return true;
+    }
+
     /**
      * Check given KeyStore against any pre-defind requirements for
      * KeyStore use, including the following.