Merge pull request moby#41984 from tonistiigi/pax-parent

archive: avoid creating parent dirs for XGlobalHeader

pkg/archive/archive.go

@@ -931,6 +931,12 @@ loop:
 			return err
 		}
 
+		// ignore XGlobalHeader early to avoid creating parent directories for them
+		if hdr.Typeflag == tar.TypeXGlobalHeader {
+			logrus.Debugf("PAX Global Extended Headers found for %s and ignored", hdr.Name)
+			continue
+		}
+
 		// Normalize name, for safety and for a simple is-root check
 		// This keeps "../" as-is, but normalizes "/../" to "/". Or Windows:
 		// This keeps "..\" as-is, but normalizes "\..\" to "\".

pkg/archive/archive_test.go

@@ -4,6 +4,7 @@ import (
 	"archive/tar"
 	"bytes"
 	"compress/gzip"
+	"errors"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -1174,6 +1175,26 @@ func TestTempArchiveCloseMultipleTimes(t *testing.T) {
 	}
 }
 
+// TestXGlobalNoParent is a regression test to check parent directories are not crated for PAX headers
+func TestXGlobalNoParent(t *testing.T) {
+	buf := &bytes.Buffer{}
+	w := tar.NewWriter(buf)
+	err := w.WriteHeader(&tar.Header{
+		Name:     "foo/bar",
+		Typeflag: tar.TypeXGlobalHeader,
+	})
+	assert.NilError(t, err)
+	tmpDir, err := ioutil.TempDir("", "pax-test")
+	assert.NilError(t, err)
+	defer os.RemoveAll(tmpDir)
+	err = Untar(buf, tmpDir, nil)
+	assert.NilError(t, err)
+
+	_, err = os.Lstat(filepath.Join(tmpDir, "foo"))
+	assert.Check(t, err != nil)
+	assert.Check(t, errors.Is(err, os.ErrNotExist))
+}
+
 func TestReplaceFileTarWrapper(t *testing.T) {
 	filesInArchive := 20
 	testcases := []struct {