Fixed SIGSEGV when dropping Channel from memory due to memory corruption

Author: JetpackDuba

src/main/kotlin/com/jetpackduba/gitnuro/credentials/SshProcess.kt

@@ -42,17 +42,15 @@ class SshProcess : Process() {
         check(!isRunning())
         println("exitValue called")
 
-        channel.close()
-
         return 0
     }
 
     override fun destroy() {
-        if (channel.isOpen()) {
-            channel.close()
-        }
+        closeChannel()
+    }
 
-        println("Destroy called")
+    fun closeChannel() {
+        channel.close()
     }
 
     private fun isRunning(): Boolean {

src/main/kotlin/com/jetpackduba/gitnuro/credentials/SshRemoteSession.kt

@@ -12,20 +12,20 @@ private const val NOT_EXPLICIT_PORT = -1
 class SshRemoteSession @Inject constructor(
     private val credentialsStateManager: CredentialsStateManager,
 ) : RemoteSession {
-    private var session: Session? = null
-
+    private lateinit var session: Session
+    private lateinit var process: SshProcess
     override fun exec(commandName: String, timeout: Int): Process {
         println("Running command $commandName")
 
-        val session = this.session ?: throw Exception("Session is null")
-        val process = SshProcess()
+        process = SshProcess()
 
         process.setup(session, commandName)
         return process
     }
 
     override fun disconnect() {
-        session?.disconnect()
+        process.closeChannel()
+        session.disconnect()
     }
 
     fun setup(uri: URIish) {

src/main/kotlin/com/jetpackduba/gitnuro/ssh/libssh/ChannelWrapper.kt

@@ -5,10 +5,13 @@ import Session
 import com.jetpackduba.gitnuro.ssh.libssh.streams.SshChannelInputErrStream
 import com.jetpackduba.gitnuro.ssh.libssh.streams.SshChannelInputStream
 import com.jetpackduba.gitnuro.ssh.libssh.streams.SshChannelOutputStream
+import java.util.concurrent.Semaphore
 
 class ChannelWrapper internal constructor(sshSession: Session) {
     private val channel = Channel.new(sshSession)
 
+    private var isClosed = false
+    private var closeMutex = Semaphore(1)
     val outputStream = SshChannelOutputStream(channel)
     val inputStream = SshChannelInputStream(channel)
     val errorOutputStream = SshChannelInputErrStream(channel)
@@ -26,7 +29,15 @@ class ChannelWrapper internal constructor(sshSession: Session) {
     }
 
     fun close() {
-        channel.closeChannel()
-        channel.close()
+        closeMutex.acquire()
+        try {
+            if (!isClosed) {
+                channel.closeChannel()
+                channel.close()
+                isClosed = true
+            }
+        } finally {
+            closeMutex.release()
+        }
     }
 }