Merge branch 'tls-hardening'

src/com/fsck/k9/mail/store/ImapStore.java

@@ -2449,7 +2449,7 @@ public class ImapStore extends Store {
                             sslContext.init(null, new TrustManager[] {
                                                 TrustManagerFactory.get(mSettings.getHost(), secure)
                                             }, new SecureRandom());
-                            mSocket = sslContext.getSocketFactory().createSocket();
+                            mSocket = TrustedSocketFactory.createSocket(sslContext);
                         } else {
                             mSocket = new Socket();
                         }

src/com/fsck/k9/mail/store/Pop3Store.java

@@ -330,7 +330,7 @@ public class Pop3Store extends Store {
                     sslContext.init(null, new TrustManager[] {
                                         TrustManagerFactory.get(mHost, secure)
                                     }, new SecureRandom());
-                    mSocket = sslContext.getSocketFactory().createSocket();
+                    mSocket = TrustedSocketFactory.createSocket(sslContext);
                 } else {
                     mSocket = new Socket();
                 }

src/com/fsck/k9/mail/store/TrustedSocketFactory.java

@@ -0,0 +1,96 @@
+package com.fsck.k9.mail.store;
+
+import javax.net.ssl.SSLContext;
+import javax.net.ssl.SSLSocket;
+import javax.net.ssl.SSLSocketFactory;
+import java.io.IOException;
+import java.net.Socket;
+import java.security.KeyManagementException;
+import java.security.NoSuchAlgorithmException;
+import java.security.SecureRandom;
+import java.util.*;
+
+
+/**
+ * Filter and reorder list of cipher suites and TLS versions.
+ *
+ * <p>
+ * See: <a href="http://op-co.de/blog/posts/android_ssl_downgrade/">http://op-co.de/blog/posts/android_ssl_downgrade/</a>
+ * </p>
+ */
+public class TrustedSocketFactory {
+    protected static final String ENABLED_CIPHERS[];
+    protected static final String ENABLED_PROTOCOLS[];
+
+    static {
+        String preferredCiphers[] = {
+            "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA",
+            "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA",
+            "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA",
+            "TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA",
+            "TLS_DHE_RSA_WITH_AES_128_CBC_SHA",
+            "TLS_DHE_RSA_WITH_AES_256_CBC_SHA",
+            "TLS_DHE_DSS_WITH_AES_128_CBC_SHA",
+            "TLS_ECDHE_RSA_WITH_RC4_128_SHA",
+            "TLS_ECDHE_ECDSA_WITH_RC4_128_SHA",
+            "TLS_RSA_WITH_AES_128_CBC_SHA",
+            "TLS_RSA_WITH_AES_256_CBC_SHA",
+            "SSL_RSA_WITH_3DES_EDE_CBC_SHA",
+            "SSL_RSA_WITH_RC4_128_SHA",
+            "SSL_RSA_WITH_RC4_128_MD5",
+        };
+        String preferredProtocols[] = {
+            "TLSv1.2", "TLSv1.1", "TLSv1"
+        };
+
+        String[] supportedCiphers = null;
+        String[] supportedProtocols = null;
+
+        try {
+            SSLContext sslContext = SSLContext.getInstance("TLS");
+            sslContext.init(null, null, new SecureRandom());
+            SSLSocketFactory sf = sslContext.getSocketFactory();
+            supportedCiphers = sf.getSupportedCipherSuites();
+            SSLSocket sock = (SSLSocket)sf.createSocket();
+            supportedProtocols = sock.getSupportedProtocols();
+        } catch (IOException ioe) {
+            ioe.printStackTrace();
+        } catch (KeyManagementException kme) {
+            kme.printStackTrace();
+        } catch (NoSuchAlgorithmException nsae) {
+            nsae.printStackTrace();
+        }
+
+        ENABLED_CIPHERS = supportedCiphers == null ? null :
+            filterBySupport(preferredCiphers, supportedCiphers);
+        ENABLED_PROTOCOLS = supportedProtocols == null ? null :
+            filterBySupport(preferredProtocols, supportedProtocols);
+    }
+
+    protected static String[] filterBySupport(String[] preferred, String[] supported) {
+        List<String> enabled = new ArrayList<String>();
+        Set<String> available = new HashSet<String>();
+        Collections.addAll(available, supported);
+
+        for (String item : preferred) {
+            if (available.contains(item)) enabled.add(item);
+        }
+        return enabled.toArray(new String[enabled.size()]);
+    }
+
+    public static Socket createSocket(SSLContext sslContext) throws IOException {
+        SSLSocket socket = (SSLSocket) sslContext.getSocketFactory().createSocket();
+        hardenSocket(socket);
+
+        return socket;
+    }
+
+    private static void hardenSocket(SSLSocket sock) {
+        if (ENABLED_CIPHERS != null) {
+            sock.setEnabledCipherSuites(ENABLED_CIPHERS);
+        }
+        if (ENABLED_PROTOCOLS != null) {
+            sock.setEnabledProtocols(ENABLED_PROTOCOLS);
+        }
+    }
+}

src/com/fsck/k9/mail/store/WebDavSocketFactory.java

@@ -1,14 +1,9 @@
-package com.fsck.k9.mail.transport;
+package com.fsck.k9.mail.store;
 
-import com.fsck.k9.mail.store.TrustManagerFactory;
 import org.apache.http.conn.ConnectTimeoutException;
 import org.apache.http.conn.scheme.LayeredSocketFactory;
 import org.apache.http.params.HttpParams;
 
-import javax.net.ssl.SSLContext;
-import javax.net.ssl.SSLSocket;
-import javax.net.ssl.SSLSocketFactory;
-import javax.net.ssl.TrustManager;
 import java.io.IOException;
 import java.net.InetAddress;
 import java.net.Socket;
@@ -17,11 +12,21 @@ import java.security.KeyManagementException;
 import java.security.NoSuchAlgorithmException;
 import java.security.SecureRandom;
 
-public class TrustedSocketFactory implements LayeredSocketFactory {
+import javax.net.ssl.SSLContext;
+import javax.net.ssl.SSLSocket;
+import javax.net.ssl.SSLSocketFactory;
+import javax.net.ssl.TrustManager;
+
+
+/*
+ * TODO: find out what's going on here and document it.
+ * Using two socket factories looks suspicious.
+ */
+public class WebDavSocketFactory implements LayeredSocketFactory {
     private SSLSocketFactory mSocketFactory;
     private org.apache.http.conn.ssl.SSLSocketFactory mSchemeSocketFactory;
 
-    public TrustedSocketFactory(String host, boolean secure) throws NoSuchAlgorithmException, KeyManagementException {
+    public WebDavSocketFactory(String host, boolean secure) throws NoSuchAlgorithmException, KeyManagementException {
         SSLContext sslContext = SSLContext.getInstance("TLS");
         sslContext.init(null, new TrustManager[] {
                 TrustManagerFactory.get(host, secure)

src/com/fsck/k9/mail/store/WebDavStore.java

@@ -10,7 +10,6 @@ import com.fsck.k9.mail.*;
 
 import com.fsck.k9.mail.filter.EOLConvertingOutputStream;
 import com.fsck.k9.mail.internet.MimeMessage;
-import com.fsck.k9.mail.transport.TrustedSocketFactory;
 import org.apache.commons.io.IOUtils;
 import org.apache.http.*;
 import org.apache.http.client.CookieStore;
@@ -1080,7 +1079,7 @@ public class WebDavStore extends Store {
 
             SchemeRegistry reg = mHttpClient.getConnectionManager().getSchemeRegistry();
             try {
-                Scheme s = new Scheme("https", new TrustedSocketFactory(mHost, mSecure), 443);
+                Scheme s = new Scheme("https", new WebDavSocketFactory(mHost, mSecure), 443);
                 reg.register(s);
             } catch (NoSuchAlgorithmException nsa) {
                 Log.e(K9.LOG_TAG, "NoSuchAlgorithmException in getHttpClient: " + nsa);

src/com/fsck/k9/mail/transport/SmtpTransport.java

@@ -14,6 +14,7 @@ import com.fsck.k9.mail.filter.SmtpDataStuffing;
 import com.fsck.k9.mail.internet.MimeUtility;
 import com.fsck.k9.mail.store.TrustManagerFactory;
 import com.fsck.k9.mail.store.LocalStore.LocalMessage;
+import com.fsck.k9.mail.store.TrustedSocketFactory;
 
 import javax.net.ssl.SSLContext;
 import javax.net.ssl.SSLException;
@@ -244,7 +245,7 @@ public class SmtpTransport extends Transport {
                         sslContext.init(null, new TrustManager[] {
                                             TrustManagerFactory.get(mHost, secure)
                                         }, new SecureRandom());
-                        mSocket = sslContext.getSocketFactory().createSocket();
+                        mSocket = TrustedSocketFactory.createSocket(sslContext);
                         mSocket.connect(socketAddress, SOCKET_CONNECT_TIMEOUT);
                     } else {
                         mSocket = new Socket();