2 files changed, 200 insertions, 0 deletions

diff --git a/app/src/main/java/org/pacien/tincapp/activities/configure/ConfigurationFtpServerFragment.kt b/app/src/main/java/org/pacien/tincapp/activities/configure/ConfigurationFtpServerFragment.kt
new file mode 100644
index 0000000..b97a15e
--- /dev/null
+++ b/app/src/main/java/org/pacien/tincapp/activities/configure/ConfigurationFtpServerFragment.kt
@@ -0,0 +1,72 @@
+/*
+ * Tinc App, an Android binding and user interface for the tinc mesh VPN daemon
+ * Copyright (C) 2017-2020 Pacien TRAN-GIRARD
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package org.pacien.tincapp.activities.configure
+
+import android.content.Intent
+import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import androidx.databinding.Observable
+import androidx.databinding.ObservableBoolean
+import org.pacien.tincapp.activities.BaseFragment
+import org.pacien.tincapp.databinding.ConfigureToolsConfigurationFtpServerFragmentBinding
+import org.pacien.tincapp.service.ConfigurationFtpService
+
+/**
+ * @author pacien
+ */
+class ConfigurationFtpServerFragment : BaseFragment() {
+  private val ftpServerStartListener = object : Observable.OnPropertyChangedCallback() {
+    override fun onPropertyChanged(sender: Observable, propertyId: Int) {
+      binding.ftpEnabled = (sender as ObservableBoolean).get()
+    }
+  }
+
+  private lateinit var binding: ConfigureToolsConfigurationFtpServerFragmentBinding
+
+  override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View {
+    binding = ConfigureToolsConfigurationFtpServerFragmentBinding.inflate(inflater, container, false)
+    binding.ftpUsername = ConfigurationFtpService.FTP_USERNAME
+    binding.ftpPassword = ConfigurationFtpService.FTP_PASSWORD
+    binding.ftpPort = ConfigurationFtpService.FTP_PORT
+    binding.toggleFtpState = { toggleServer() }
+    return binding.root
+  }
+
+  override fun onResume() {
+    super.onResume()
+    ConfigurationFtpService.runningState.addOnPropertyChangedCallback(ftpServerStartListener)
+    binding.ftpEnabled = ConfigurationFtpService.runningState.get()
+  }
+
+  override fun onPause() {
+    ConfigurationFtpService.runningState.removeOnPropertyChangedCallback(ftpServerStartListener)
+    super.onPause()
+  }
+
+  private fun toggleServer() {
+    val targetServiceIntent = Intent(requireContext(), ConfigurationFtpService::class.java)
+
+    if (binding.ftpEnabled)
+      requireContext().stopService(targetServiceIntent)
+    else
+      requireContext().startService(targetServiceIntent)
+  }
+}
diff --git a/app/src/main/java/org/pacien/tincapp/service/ConfigurationFtpService.kt b/app/src/main/java/org/pacien/tincapp/service/ConfigurationFtpService.kt
new file mode 100644
index 0000000..c562768
--- /dev/null
+++ b/app/src/main/java/org/pacien/tincapp/service/ConfigurationFtpService.kt
@@ -0,0 +1,128 @@
+/*
+ * Tinc App, an Android binding and user interface for the tinc mesh VPN daemon
+ * Copyright (C) 2017-2020 Pacien TRAN-GIRARD
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package org.pacien.tincapp.service
+
+import android.app.Service
+import android.content.Intent
+import android.os.IBinder
+import androidx.databinding.ObservableBoolean
+import org.apache.ftpserver.FtpServer
+import org.apache.ftpserver.FtpServerFactory
+import org.apache.ftpserver.ftplet.*
+import org.apache.ftpserver.listener.ListenerFactory
+import org.apache.ftpserver.usermanager.UsernamePasswordAuthentication
+import org.apache.ftpserver.usermanager.impl.WritePermission
+import org.pacien.tincapp.R
+import org.pacien.tincapp.context.App
+import org.pacien.tincapp.extensions.Java.defaultMessage
+import org.slf4j.LoggerFactory
+import java.io.IOException
+
+/**
+ * FTP server service allowing a remote and local user to access and modify configuration files in
+ * the application's context.
+ *
+ * @author pacien
+ */
+class ConfigurationFtpService : Service() {
+  companion object {
+    const val FTP_PORT = 65521 // tinc port `concat` FTP port
+    const val FTP_USERNAME = "tincapp"
+    val FTP_HOME_DIR = App.getContext().applicationInfo.dataDir!!
+    val FTP_PASSWORD = generateRandomString(8)
+
+    val runningState = ObservableBoolean(false)
+
+    private fun generateRandomString(length: Int): String {
+      val alphabet = ('a'..'z') + ('A'..'Z') + ('0'..'9')
+      return List(length) { alphabet.random() }.joinToString("")
+    }
+  }
+
+  private val log by lazy { LoggerFactory.getLogger(this.javaClass)!! }
+  private var sftpServer: FtpServer? = null
+
+  override fun onBind(intent: Intent): IBinder? = null // non-bindable service
+
+  override fun onDestroy() {
+    sftpServer?.stop()
+    sftpServer = null
+    runningState.set(false)
+    log.info("Stopped FTP server")
+    super.onDestroy()
+  }
+
+  override fun onStartCommand(intent: Intent, flags: Int, startId: Int): Int {
+    val ftpUser = StaticFtpUser(FTP_USERNAME, FTP_PASSWORD, FTP_HOME_DIR, listOf(WritePermission()))
+    sftpServer = setupSingleUserServer(ftpUser).also {
+      try {
+        it.start()
+        runningState.set(true)
+        log.info("Started FTP server on port {}", FTP_PORT)
+      } catch (e: IOException) {
+        log.error("Could not start FTP server", e)
+        App.alert(R.string.notification_error_title_unable_to_start_ftp_server, e.defaultMessage())
+      }
+    }
+
+    return START_NOT_STICKY
+  }
+
+  private fun setupSingleUserServer(ftpUser: User): FtpServer {
+    return FtpServerFactory()
+      .apply { addListener("default", ListenerFactory().apply { port = FTP_PORT }.createListener()) }
+      .apply { userManager = StaticFtpUserManager(listOf(ftpUser)) }
+      .createServer()
+  }
+
+  private class StaticFtpUserManager(users: List<User>) : UserManager {
+    private val userMap: Map<String, User> = users.map { it.name to it }.toMap()
+    override fun getUserByName(username: String?): User? = userMap[username]
+    override fun getAllUserNames(): Array<String> = userMap.keys.toTypedArray()
+    override fun doesExist(username: String?): Boolean = username in userMap
+    override fun delete(username: String?) = throw UnsupportedOperationException()
+    override fun save(user: User?) = throw UnsupportedOperationException()
+    override fun getAdminName(): String = throw UnsupportedOperationException()
+    override fun isAdmin(username: String?): Boolean = throw UnsupportedOperationException()
+    override fun authenticate(authentication: Authentication?): User = when (authentication) {
+      is UsernamePasswordAuthentication -> getUserByName(authentication.username).let {
+        if (it != null && authentication.password == it.password) it
+        else throw AuthenticationFailedException()
+      }
+      else -> throw IllegalArgumentException()
+    }
+  }
+
+  private data class StaticFtpUser(
+    private val name: String,
+    private val password: String,
+    private val homeDirectory: String,
+    private val authorities: List<Authority>
+  ) : User {
+    override fun getName(): String = name
+    override fun getPassword(): String = password