implement publickey authentication in JavaFileStorage (not yet integrated in main app)

src/java/JavaFileStorage/app/src/main/java/keepass2android/javafilestorage/SftpStorage.java

@@ -2,7 +2,9 @@ package keepass2android.javafilestorage;
 
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
+import java.io.File;
 import java.io.FileNotFoundException;
+import java.io.IOException;
 import java.io.InputStream;
 import java.io.UnsupportedEncodingException;
 import java.util.ArrayList;
@@ -13,6 +15,7 @@ import com.jcraft.jsch.ChannelSftp;
 import com.jcraft.jsch.ChannelSftp.LsEntry;
 import com.jcraft.jsch.JSch;
 import com.jcraft.jsch.JSchException;
+import com.jcraft.jsch.KeyPair;
 import com.jcraft.jsch.Session;
 import com.jcraft.jsch.SftpATTRS;
 import com.jcraft.jsch.SftpException;
@@ -21,6 +24,7 @@ import com.jcraft.jsch.UserInfo;
 import android.content.Context;
 import android.content.Intent;
 import android.os.Bundle;
+import android.support.annotation.NonNull;
 
 public class SftpStorage extends JavaFileStorageBase {
 
@@ -320,14 +324,28 @@ public class SftpStorage extends JavaFileStorageBase {
 		jsch = new JSch();
 		ConnectionInfo ci = splitStringToConnectionInfo(filename);
 
-		jsch.setKnownHosts(_appContext.getFilesDir().getAbsolutePath() + "/known_hosts");
+		String base_dir = getBaseDir();
+		jsch.setKnownHosts(base_dir + "/known_hosts");
+
+		String key_filename = getKeyFileName();
+		try{
+			createKeyPair(key_filename);
+		} catch (Exception ex) {
+			System.out.println(ex);
+		}
+
+		try {
+			jsch.addIdentity(key_filename);
+		} catch (java.lang.Exception e)
+		{
+
+		}
 
 		Session session = jsch.getSession(ci.username, ci.host, ci.port);
 		UserInfo ui = new SftpUserInfo(ci.password,_appContext);
 		session.setUserInfo(ui);
 
-		session.setConfig("PreferredAuthentications",
-				"password,publickey");
+		session.setConfig("PreferredAuthentications", "publickey,password");
 
 		session.connect();
 
@@ -340,6 +358,37 @@ public class SftpStorage extends JavaFileStorageBase {
 
 	}
 
+	@NonNull
+	private String getBaseDir() {
+		return _appContext.getFilesDir().getAbsolutePath();
+	}
+
+	@NonNull
+	private String getKeyFileName() {
+		return getBaseDir() + "/id_kp2a_rsa";
+	}
+
+	public String createKeyPair() throws IOException, JSchException {
+		return createKeyPair(getKeyFileName());
+
+	}
+
+	private String createKeyPair(String key_filename) throws JSchException, IOException {
+		String public_key_filename = key_filename + ".pub";
+		File file = new File(key_filename);
+		if (file.exists())
+			return public_key_filename;
+		int type = KeyPair.RSA;
+		KeyPair kpair = KeyPair.genKeyPair(jsch, type, 2048);
+		kpair.writePrivateKey(key_filename);
+
+		kpair.writePublicKey(public_key_filename, "generated by Keepass2Android");
+		//ret = "Fingerprint: " + kpair.getFingerPrint();
+		kpair.dispose();
+		return public_key_filename;
+
+	}
+
 	public ConnectionInfo splitStringToConnectionInfo(String filename)
 			throws UnsupportedEncodingException {
 		ConnectionInfo ci = new ConnectionInfo();

src/java/JavaFileStorage/app/src/main/res/layout/notfif_slave.xml

@@ -0,0 +1,38 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:orientation="vertical"
+    android:layout_width="fill_parent"
+    android:layout_height="fill_parent"
+    android:padding="10dp"
+    >
+    <TextView
+        android:id="@+id/prompt"
+        android:layout_width="fill_parent"
+        android:layout_height="wrap_content"
+        />
+    <EditText
+        android:id="@+id/entry"
+        android:layout_width="fill_parent"
+        android:layout_height="wrap_content"
+        android:background="@android:drawable/editbox_background"
+        android:password="true"
+        />
+    <LinearLayout
+        android:orientation="horizontal"
+        android:layout_width="fill_parent"
+        android:layout_height="wrap_content"
+        >
+        <Button
+            android:id="@+id/ok"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:text="OK"
+            />
+        <Button
+            android:id="@+id/cancel"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:text="Cancel"
+            />
+    </LinearLayout>
+</LinearLayout>

src/java/JavaFileStorageTest-AS/app/src/main/java/com/crocoapps/javafilestoragetest/MainActivity.java

@@ -135,7 +135,12 @@ package com.crocoapps.javafilestoragetest;
 import group.pals.android.lib.ui.filechooser.FileChooserActivity;
 import group.pals.android.lib.ui.filechooser.providers.BaseFileProviderUtils;
 
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
 import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.Reader;
 import java.io.UnsupportedEncodingException;
 import java.util.ArrayList;
 import java.util.List;
@@ -662,6 +667,20 @@ public class MainActivity extends Activity implements JavaFileStorage.FileStorag
 		return this;
 	}
 
+	public static String readStream(InputStream is) {
+		StringBuilder sb = new StringBuilder(512);
+		try {
+			Reader r = new InputStreamReader(is, "UTF-8");
+			int c = 0;
+			while ((c = r.read()) != -1) {
+				sb.append((char) c);
+			}
+		} catch (IOException e) {
+			throw new RuntimeException(e);
+		}
+		return sb.toString();
+	}
+
 	@Override
 	public void performManualFileSelect(boolean isForSave, final int requestCode,
 			String protocolId)
@@ -669,6 +688,30 @@ public class MainActivity extends Activity implements JavaFileStorage.FileStorag
 		if (protocolId.equals("sftp"))
 		{
 			final View view = getLayoutInflater().inflate(R.layout.sftp_credentials, null);
+
+			view.findViewById(R.id.send_public_key).setOnClickListener(v -> {
+				Intent sendIntent = new Intent();
+
+
+                SftpStorage sftpStorage = (SftpStorage)storageToTest;
+                try {
+                    String pub_filename = sftpStorage.createKeyPair();
+
+                    sendIntent.setAction(Intent.ACTION_SEND);
+                    sendIntent.putExtra(Intent.EXTRA_TEXT, readStream(new FileInputStream(pub_filename)));
+
+                    sendIntent.putExtra(Intent.EXTRA_SUBJECT, "Keepass2Android sftp public key");
+                    sendIntent.setType("text/plain");
+                    this.startActivity(Intent.createChooser(sendIntent, "Send public key to..."));
+                }
+                catch (Exception ex)
+                {
+                    Toast.makeText(this,"Failed to create key pair: " + ex.getMessage(), Toast.LENGTH_LONG);
+                    return;
+                }
+
+
+			});
 			new AlertDialog.Builder(this)
 					.setView(view)
 					.setTitle("Enter SFTP credentials")

src/java/JavaFileStorageTest-AS/app/src/main/res/layout/sftp_credentials.xml

@@ -15,7 +15,7 @@
             android:layout_height="wrap_content"
             android:singleLine="true"
             android:inputType="textNoSuggestions"
-            android:text=""
+            android:text="philipp-gross"
 			android:hint="@string/hint_sftp_host" />
 	  <TextView
             android:id="@+id/portsep"
@@ -63,6 +63,9 @@
             android:singleLine="true"
 			android:text="/home/philipp"
 			 />
-		
+		<Button android:id="@+id/send_public_key"
+			android:layout_width="fill_parent"
+			android:layout_height="wrap_content"
+			android:text="send public key" />
 
 </LinearLayout>