Fix host UID/GID leakage in copyFileToContainer TAR entries

Author: Gautam-aman

core/src/main/java/org/testcontainers/utility/MountableFile.java

@@ -353,6 +353,10 @@ private void recursiveTar(
             }
 
             final TarArchiveEntry tarEntry = new TarArchiveEntry(sourceFile, tarEntryFilename.replaceAll("^/", ""));
+            tarEntry.setUserId(0);
+            tarEntry.setGroupId(0);
+            tarEntry.setUserName("root");
+            tarEntry.setGroupName("root");
 
             // TarArchiveEntry automatically sets the mode for file/directory, but we can update to ensure that the mode is set exactly (inc executable bits)
             tarEntry.setMode(getUnixFileMode(itemPath));

core/src/test/java/org/testcontainers/utility/MountableFileTest.java

@@ -2,6 +2,7 @@
 
 import lombok.Cleanup;
 import org.apache.commons.compress.archivers.ArchiveEntry;
+import org.apache.commons.compress.archivers.tar.TarArchiveEntry;
 import org.apache.commons.compress.archivers.tar.TarArchiveInputStream;
 import org.apache.commons.compress.archivers.tar.TarArchiveOutputStream;
 import org.jetbrains.annotations.NotNull;
@@ -32,6 +33,27 @@ void forClasspathResource() throws Exception {
         performChecks(mountableFile);
     }
 
+    @Test
+    void tarEntriesShouldUseRootOwnership() throws Exception {
+        final Path file = createTempFile("ownership-test.txt");
+        final MountableFile mountableFile = MountableFile.forHostPath(file);
+
+        @Cleanup
+        final TarArchiveInputStream tais = intoTarArchive(taos -> {
+            mountableFile.transferTo(taos, "/ownership-test.txt");
+        });
+
+        final TarArchiveEntry tarEntry = tais.getNextEntry();
+
+        assertThat(tarEntry).isNotNull();
+
+        System.out.println("UID = " + tarEntry.getLongUserId());
+        System.out.println("GID = " + tarEntry.getLongGroupId());
+
+        assertThat(tarEntry.getLongUserId()).isZero();
+        assertThat(tarEntry.getLongGroupId()).isZero();
+    }
+
     @Test
     void forClasspathResourceWithAbsolutePath() throws Exception {
         final MountableFile mountableFile = MountableFile.forClasspathResource("/mappable-resource/test-resource.txt");