How to connect to FTPS server with reuse sessions?

Question

I am using the Apache Commons FTP library in my android application.

I am trying to connect to my FTPS server from my application (using Android Studio) and then upload some files.

However when I want to reuse sessions by overiding the method _prepareDataSocket_ from FTPSClient, I always have the same error about :java.lang.NoSuchFieldException: sessionHostPortCache. I have tried with the code from the others posts : How to connect to FTPS server with data connection using same TLS session? or Transfer files from android with FTPS to the server Do you know why I have this error ?

I'm using Android studio with jdk 1.8.

I appreciate any help, thanks.

Main code :

String server = "ftp.[HIDDEN]";
int port = 21;
String user = "[HIDDEN]";
String pass = "[HIDDEN]";

System.setProperty("jdk.tls.useExtendedMasterSecret", "false");
SSLSessionReuseFTPSClient ftpClient = new SSLSessionReuseFTPSClient("SSL");
ftpClient.addProtocolCommandListener(new PrintCommandListener(new PrintWriter(System.out), true));
                

ftpClient.connect(server, port);
System.out.println("Connected to " + server + " on " + port);

ftpClient.login(user, pass);

ftpClient.execPBSZ(0);
ftpClient.execPROT("P");
ftpClient.setFileType(FTP.BINARY_FILE_TYPE);
ftpClient.enterLocalPassiveMode();

// transfer files
InputStream input;
input = new FileInputStream(local);
ftpClient.storeFile(remote, input);
input.close();

ftpClient.noop(); // check that control connection is working OK
ftpClient.logout();

SSLSessionReuseFTPSClient :

public class SSLSessionReuseFTPSClient extends FTPSClient {

    public SSLSessionReuseFTPSClient(String protocol) {
        super(protocol);
    }

    // adapted from: https://trac.cyberduck.io/changeset/10760
    @Override
    protected void _prepareDataSocket_(final Socket socket) throws IOException {
        if (socket instanceof SSLSocket) {
            // Control socket is SSL
            final SSLSession session = ((SSLSocket) _socket_).getSession();
            if (session.isValid()) {
                final SSLSessionContext context = session.getSessionContext();
                try {
                    final Field sessionHostPortCache = context.getClass().getDeclaredField("sessionHostPortCache");
                    sessionHostPortCache.setAccessible(true);
                    final Object cache = sessionHostPortCache.get(context);
                    final Method method = cache.getClass().getDeclaredMethod("put", Object.class, Object.class);
                    method.setAccessible(true);
                    method.invoke(cache, String
                            .format("%s:%s", socket.getInetAddress().getHostName(), String.valueOf(socket.getPort()))
                            .toLowerCase(Locale.ROOT), session);
                    method.invoke(cache, String
                            .format("%s:%s", socket.getInetAddress().getHostAddress(), String.valueOf(socket.getPort()))
                            .toLowerCase(Locale.ROOT), session);
                } catch (NoSuchFieldException e) {
                    throw new IOException(e);
                } catch (Exception e) {
                    throw new IOException(e);
                }
            } else {
                throw new IOException("Invalid SSL Session");
            }
        }
    }
}

Logcat :

220---------- Welcome to Pure-FTPd [privsep] [TLS] ----------
07-22 09:53:59.516 9529-9561/com.example.test I/System.out: 220-You are user number 1 of 50 allowed.
07-22 09:53:59.516 9529-9561/com.example.test I/System.out: 220-Local time is now 11:54. Server port: 21.
07-22 09:53:59.516 9529-9561/com.example.test I/System.out: 220-This is a private system - No anonymous login
07-22 09:53:59.516 9529-9561/com.example.test I/System.out: 220-IPv6 connections are also welcome on this server.
07-22 09:53:59.516 9529-9561/com.example.test I/System.out: 220 You will be disconnected after 15 minutes of inactivity.
07-22 09:53:59.519 9529-9561/com.example.test I/System.out: AUTH TLS
07-22 09:53:59.533 9529-9561/com.example.test I/System.out: 234 AUTH TLS OK.
07-22 09:53:59.561 9529-9550/com.example.test D/EGL_emulation: eglMakeCurrent: 0xadc34d60: ver 2 0 (tinfo 0xadc394d0)
07-22 09:53:59.589 9529-9550/com.example.test D/EGL_emulation: eglMakeCurrent: 0xadc34d60: ver 2 0 (tinfo 0xadc394d0)
07-22 09:53:59.593 9529-9561/com.example.test I/System.out: Connected to ftp.[HIDDEN] on 21
07-22 09:53:59.597 9529-9561/com.example.test I/System.out: USER *******
07-22 09:53:59.609 9529-9561/com.example.test I/System.out: 331 User [HIDDEN] OK. Password required
07-22 09:53:59.610 9529-9561/com.example.test I/System.out: PASS *******
07-22 09:53:59.613 9529-9550/com.example.test D/EGL_emulation: eglMakeCurrent: 0xadc34d60: ver 2 0 (tinfo 0xadc394d0)
07-22 09:53:59.695 9529-9550/com.example.test D/EGL_emulation: eglMakeCurrent: 0xadc34d60: ver 2 0 (tinfo 0xadc394d0)
07-22 09:53:59.701 9529-9561/com.example.test I/System.out: 230 OK. Current restricted directory is /
07-22 09:53:59.702 9529-9561/com.example.test I/System.out: PBSZ 0
07-22 09:53:59.714 9529-9561/com.example.test I/System.out: 200 PBSZ=0
07-22 09:53:59.717 9529-9561/com.example.test I/System.out: PROT P
07-22 09:53:59.727 9529-9561/com.example.test I/System.out: 200 Data protection level set to "private"
07-22 09:53:59.729 9529-9561/com.example.test I/System.out: TYPE I
07-22 09:53:59.743 9529-9561/com.example.test I/System.out: 200 TYPE is now 8-bit binary
07-22 09:53:59.743 9529-9561/com.example.test I/System.out: PASV
07-22 09:53:59.757 9529-9550/com.example.test D/EGL_emulation: eglMakeCurrent: 0xadc34d60: ver 2 0 (tinfo 0xadc394d0)
07-22 09:53:59.758 9529-9561/com.example.test I/System.out: 227 Entering Passive Mode (5,134,13,241,188,161)
07-22 09:53:59.777 9529-9550/com.example.test D/EGL_emulation: eglMakeCurrent: 0xadc34d60: ver 2 0 (tinfo 0xadc394d0)
07-22 09:53:59.782 9529-9561/com.example.test I/System.out: STOR pictures/test 18.07 1431/test 18.07 1431_19.6.2019_0.32.15.667.jpg
07-22 09:53:59.792 9529-9561/com.example.test I/System.out: 150 Accepted data connection
07-22 09:53:59.793 9529-9561/com.example.test W/System.err: java.io.IOException: java.lang.NoSuchFieldException: sessionHostPortCache
07-22 09:53:59.793 9529-9561/com.example.test W/System.err:     at com.example.test.functions.SSLSessionReuseFTPSClient._prepareDataSocket_(SSLSessionReuseFTPSClient.java:54)
07-22 09:53:59.793 9529-9561/com.example.test W/System.err:     at org.apache.commons.net.ftp.FTPSClient._openDataConnection_(FTPSClient.java:628)
07-22 09:53:59.793 9529-9561/com.example.test W/System.err:     at org.apache.commons.net.ftp.FTPClient._storeFile(FTPClient.java:653)
07-22 09:53:59.793 9529-9561/com.example.test W/System.err:     at org.apache.commons.net.ftp.FTPClient.__storeFile(FTPClient.java:639)
07-22 09:53:59.793 9529-9561/com.example.test W/System.err:     at org.apache.commons.net.ftp.FTPClient.storeFile(FTPClient.java:2030)
07-22 09:53:59.793 9529-9561/com.example.test W/System.err:     at com.example.test.functions.FTPfunctions2$BackGroundWorker.doInBackground(FTPfunctions2.java:81)
07-22 09:53:59.793 9529-9561/com.example.test W/System.err:     at com.example.test.functions.FTPfunctions2$BackGroundWorker.doInBackground(FTPfunctions2.java:41)
07-22 09:53:59.794 9529-9561/com.example.test W/System.err:     at android.os.AsyncTask$2.call(AsyncTask.java:292)
07-22 09:53:59.794 9529-9561/com.example.test W/System.err:     at java.util.concurrent.FutureTask.run(FutureTask.java:237)
07-22 09:53:59.794 9529-9561/com.example.test W/System.err:     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
07-22 09:53:59.794 9529-9561/com.example.test W/System.err:     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
07-22 09:53:59.794 9529-9561/com.example.test W/System.err:     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
07-22 09:53:59.794 9529-9561/com.example.test W/System.err:     at java.lang.Thread.run(Thread.java:818)
07-22 09:53:59.794 9529-9561/com.example.test W/System.err: Caused by: java.lang.NoSuchFieldException: sessionHostPortCache
07-22 09:53:59.794 9529-9561/com.example.test W/System.err:     at java.lang.Class.getDeclaredField(Class.java:890)
07-22 09:53:59.794 9529-9561/com.example.test W/System.err:     at com.example.test.functions.SSLSessionReuseFTPSClient._prepareDataSocket_(SSLSessionReuseFTPSClient.java:42)
07-22 09:53:59.794 9529-9561/com.example.test W/System.err:     ... 12 more

It most probably something special about the JDK/JRE you are using (a different implementation of `SSLSocket`). Did you test the same code on desktop Java? You should narrow down the issue to get decent answers. — Martin Prikryl, Jul 22 '19 at 11:13
I redownload Jdk 1.8 but it's still not working. Sorry, I don't understand what you mean with desktop java. — LeclerT, Jul 22 '19 at 14:00
This technique breaks down with Java 11 with a 'NoSuchMethodException' on 'socket.getInetAddress().getHostName()'. Any suggestions? — Ahadu Tsegaye Abebe, Mar 31 '22 at 10:13
To answer my own question: it should be enough to replace “getHost” which no longer exists with “getPeerHost” — Ahadu Tsegaye Abebe, Apr 07 '22 at 08:19

AllaG · Answer 1 · 2020-01-18T21:04:21.470

I have encountered the same error when I change java.security to use ssl security provider other then SunJSSE. Particularly in my case I change it to: security.provider.4=org.bouncycastle.jsse.provider.BouncyCastleJsseProvider instead security.provider.4=com.sun.net.ssl.internal.ssl.Provider

1) Check your java.security file.

2) I have added a log message to the class which shows what implementation of SSLSessionContext is actually used.

logger.debug("sessionContext calss = " + sessionContext.getClass().getCanonicalName());
final Field sessionHostPortCache = sessionContext.getClass().getDeclaredField("sessionHostPortCache");

I found indeed that BouncyCastle org.bouncycastle.jsse.provider.ProvSSLSessionContext class doesn't have a sessionHostPortCache member. You can try this to discover the problem.

Another reason for getting java.lang.NoSuchFieldException is because JRE bytecode underwent obfuscation. Thus the sessionHostPortCache field could be named for example "b".

You can check this by opening the SSLSessionContext.class in your IDE and if you install decompiler plugin it will show the source code.

score 0 · Answer 2 · answered Jun 08 '23 at 17:18

There's two problems with these kinds of solutions for Android.

A lot of them are referencing different classes than the android specific implementations of session context classes, so you have to change your code to reflect correctly on android's implementation. This isn't specifically a problem, particularly given that android is open source.
Android blocks reflection on many of it's system classes, including the session context class. This is probably not work aroundable and these solutions are likely dead in the water on android.

I tend to see in logcat an error saying the reflection was blocked prior to the "not found" exception, so your code is likely suffering from both problems (not that fixing #1 would help you anyway).

How to connect to FTPS server with reuse sessions?

Main code :

SSLSessionReuseFTPSClient :

Logcat :

2 Answers2

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