Close SQL injection bug in BACKUP command

src/main/scala/fr/brouillard/gitbucket/h2/controller/H2BackupController.scala

@@ -3,7 +3,7 @@ package fr.brouillard.gitbucket.h2.controller
 import java.io.File
 import java.util.Date
 import fr.brouillard.gitbucket.h2._
-import fr.brouillard.gitbucket.h2.controller.H2BackupController.{defaultBackupFileName, doBackup}
+import fr.brouillard.gitbucket.h2.controller.H2BackupController.{defaultBackupFileName, doBackup, exportConnectedDatabase, logger}
 import gitbucket.core.controller.ControllerBase
 import gitbucket.core.model.Account
 import gitbucket.core.util.AdminAuthenticator
@@ -13,7 +13,13 @@ import org.scalatra.{ActionResult, Ok, Params}
 import org.slf4j.LoggerFactory
 import org.scalatra.forms._
 
+import java.sql.Connection
+import scala.util.Using
+
 object H2BackupController {
+
+  private val logger = LoggerFactory.getLogger(classOf[H2BackupController])
+
   def defaultBackupFileName(): String = {
     val format = new java.text.SimpleDateFormat("yyyy-MM-dd_HH-mm")
     "gitbucket-db-" + format.format(new Date()) + ".zip"
@@ -28,28 +34,32 @@ object H2BackupController {
       case _ => org.scalatra.Unauthorized()
     }
   }
+
+  def exportConnectedDatabase(conn: Connection, exportFile: File): Unit = {
+    val destFile = if (exportFile.isAbsolute) exportFile else new File(GitBucketHome + "/backup", exportFile.toString)
+
+    logger.info("Exporting database to {}", destFile)
+
+    Using.resource(conn.prepareStatement("BACKUP TO ?")){ statement =>
+      statement.setString(1, destFile.toString)
+      statement.execute()
+    }
+
+    logger.info("Exported {} bytes.", exportFile.length())
+  }
+
 }
 
 class H2BackupController extends ControllerBase with AdminAuthenticator {
-  private val logger = LoggerFactory.getLogger(classOf[H2BackupController])
 
   case class BackupForm(destFile: String)
 
   private val backupForm = mapping(
     "dest" -> trim(label("Destination", text(required)))
   )(BackupForm.apply)
 
-  // private val defaultBackupFile:String = new File(GitBucketHome, "gitbucket-database-backup.zip").toString;
-
   def exportDatabase(exportFile: File): Unit = {
-    val destFile = if (exportFile.isAbsolute) exportFile else new File(GitBucketHome + "/backup", exportFile.toString)
-
-    val session = Database.getSession(request)
-    val conn = session.conn
-
-    logger.info("exporting database to {}", destFile)
-
-    conn.prepareStatement("BACKUP TO '" + destFile + "'").execute()
+    exportConnectedDatabase(Database.getSession(request).conn, exportFile)
   }
 
   get("/admin/h2backup")(adminOnly {

src/test/scala/fr/brouillard/gitbucket/h2/controller/H2BackupControllerTests.scala

@@ -2,13 +2,18 @@ package fr.brouillard.gitbucket.h2.controller
 
 import gitbucket.core.model.Account
 import gitbucket.core.servlet.ApiAuthenticationFilter
+import org.apache.commons.io.FileSystemUtils
+import org.h2.Driver
+import org.h2.engine.Database
 import org.scalatest.funsuite.AnyFunSuite
 import org.scalatest.matchers.should.Matchers.{convertToAnyShouldWrapper, equal}
 import org.scalatra.{Ok, Params, ScalatraParams}
 import org.scalatra.test.scalatest.ScalatraFunSuite
 
 import java.io.File
-import java.util.Date
+import java.nio.file.{Files, Path, Paths}
+import java.util.{Date, Properties}
+import scala.util.Using
 
 class H2BackupControllerTests extends ScalatraFunSuite {
   addFilter(classOf[ApiAuthenticationFilter], path="/api/*")
@@ -59,6 +64,49 @@ class H2BackupControllerObjectTests extends AnyFunSuite {
       description = None)
   }
 
+  private def h2Url(file: File): String = {
+    "jdbc:h2:file:" + file + ";DATABASE_TO_UPPER=false"
+  }
+
+  test("exports connected database with safe file name") {
+    exportsConnectedDatabase("backup.zip")
+  }
+
+  test("exports connected database with unsafe file name") {
+    exportsConnectedDatabase("data.zip' drop database xyx")
+  }
+
+  private def exportsConnectedDatabase(backupFileName: String): Unit = {
+    val tempDir = Files.createTempDirectory(classOf[H2BackupControllerObjectTests].getName + "-exports-connected-database")
+    try {
+      val requestedDbFile = new File(tempDir.toFile, "data")
+      // H2 can create several files; in this case, it will only create a data file and no lock files.
+      val createdDbFile = new File(tempDir.toFile, "data.mv.db")
+      val backup = new File(tempDir.toFile, backupFileName)
+
+      val driver = new Driver()
+      val conn = driver.connect(h2Url(requestedDbFile), new Properties());
+      try {
+        assert(createdDbFile.exists())
+
+        H2BackupController.exportConnectedDatabase(conn, backup)
+        try {
+          assert(backup.length() > 0)
+        }
+        finally {
+          assert(backup.delete())
+        }
+      }
+      finally {
+        conn.close()
+        assert(createdDbFile.delete())
+      }
+    }
+    finally {
+      assert(tempDir.toFile.delete())
+    }
+  }
+
   test("generates default file name") {
     assertDefaultFileName(H2BackupController.defaultBackupFileName())
   }