update zip_read_closer to incorporate zip64 support (#1041)

internal/file/test-fixtures/generate-zip-fixture-from-source-dir.sh

@@ -3,5 +3,10 @@ set -eux
 
 # $1 —— absolute path to destination file, should end with .zip, ideally
 # $2 —— absolute path to directory from which to add entries to the archive
+# $3 —— if files should be zip64 or not
 
+if [[$3]]; then
+	pushd "$2" && find . -print | zip -fz "$1" -@ && popd
+else
 	pushd "$2" && find . -print | zip "$1" -@ && popd
+fi

internal/file/zip_file_helpers_test.go

@@ -20,16 +20,20 @@ var expectedZipArchiveEntries = []string{
 }
 
 // createZipArchive creates a new ZIP archive file at destinationArchivePath based on the directory found at
-// sourceDirPath.
-func createZipArchive(t testing.TB, sourceDirPath, destinationArchivePath string) {
+// sourceDirPath. It forces a zip64 archive if zip64 is "0".
+func createZipArchive(t testing.TB, sourceDirPath, destinationArchivePath string, zip64 bool) {
 	t.Helper()
 
 	cwd, err := os.Getwd()
 	if err != nil {
 		t.Fatalf("unable to get cwd: %+v", err)
 	}
+	zip64Arg := "0"
+	if zip64 {
+		zip64Arg = "1"
+	}
 
-	cmd := exec.Command("./generate-zip-fixture-from-source-dir.sh", destinationArchivePath, path.Base(sourceDirPath))
+	cmd := exec.Command("./generate-zip-fixture-from-source-dir.sh", destinationArchivePath, path.Base(sourceDirPath), zip64Arg)
 	cmd.Dir = filepath.Join(cwd, "test-fixtures")
 
 	if err := cmd.Start(); err != nil {
@@ -66,7 +70,7 @@ func assertNoError(t testing.TB, fn func() error) func() {
 // which should be called (typically deferred) by the caller, the path of the created zip archive, and an error,
 // which should trigger a fatal test failure in the consuming test. The returned cleanup function will never be nil
 // (even if there's an error), and it should always be called.
-func setupZipFileTest(t testing.TB, sourceDirPath string) string {
+func setupZipFileTest(t testing.TB, sourceDirPath string, zip64 bool) string {
 	t.Helper()
 
 	archivePrefix, err := ioutil.TempFile("", "syft-ziputil-archive-TEST-")
@@ -84,7 +88,7 @@ func setupZipFileTest(t testing.TB, sourceDirPath string) string {
 
 	destinationArchiveFilePath := archivePrefix.Name() + ".zip"
 	t.Logf("archive path: %s", destinationArchiveFilePath)
-	createZipArchive(t, sourceDirPath, destinationArchiveFilePath)
+	createZipArchive(t, sourceDirPath, destinationArchiveFilePath, zip64)
 
 	t.Cleanup(
 		assertNoError(t,
@@ -109,7 +113,7 @@ func ensureNestedZipExists(t *testing.T, sourceDirPath string) error {
 	t.Helper()
 
 	nestedArchiveFilePath := path.Join(sourceDirPath, "nested.zip")
-	createZipArchive(t, sourceDirPath, nestedArchiveFilePath)
+	createZipArchive(t, sourceDirPath, nestedArchiveFilePath, false)
 
 	return nil
 }

internal/file/zip_file_manifest_test.go

@@ -22,7 +22,42 @@ func TestNewZipFileManifest(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	archiveFilePath := setupZipFileTest(t, sourceDirPath)
+	archiveFilePath := setupZipFileTest(t, sourceDirPath, false)
+
+	actual, err := NewZipFileManifest(archiveFilePath)
+	if err != nil {
+		t.Fatalf("unable to extract from unzip archive: %+v", err)
+	}
+
+	if len(expectedZipArchiveEntries) != len(actual) {
+		t.Fatalf("mismatched manifest: %d != %d", len(actual), len(expectedZipArchiveEntries))
+	}
+
+	for _, e := range expectedZipArchiveEntries {
+		_, ok := actual[e]
+		if !ok {
+			t.Errorf("missing path: %s", e)
+		}
+	}
+
+	if t.Failed() {
+		b, err := json.MarshalIndent(actual, "", "  ")
+		if err != nil {
+			t.Fatalf("can't show results: %+v", err)
+		}
+
+		t.Errorf("full result: %s", string(b))
+	}
+}
+
+func TestNewZip64FileManifest(t *testing.T) {
+	cwd, err := os.Getwd()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	sourceDirPath := path.Join(cwd, "test-fixtures", "zip-source")
+	archiveFilePath := setupZipFileTest(t, sourceDirPath, true)
 
 	actual, err := NewZipFileManifest(archiveFilePath)
 	if err != nil {
@@ -62,7 +97,7 @@ func TestZipFileManifest_GlobMatch(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	archiveFilePath := setupZipFileTest(t, sourceDirPath)
+	archiveFilePath := setupZipFileTest(t, sourceDirPath, false)
 
 	z, err := NewZipFileManifest(archiveFilePath)
 	if err != nil {

internal/file/zip_file_traversal_test.go

@@ -47,7 +47,7 @@ func TestUnzipToDir(t *testing.T) {
 
 	goldenRootDir := filepath.Join(cwd, "test-fixtures")
 	sourceDirPath := path.Join(goldenRootDir, "zip-source")
-	archiveFilePath := setupZipFileTest(t, sourceDirPath)
+	archiveFilePath := setupZipFileTest(t, sourceDirPath, false)
 
 	unzipDestinationDir, err := ioutil.TempDir("", "syft-ziputil-contents-TEST-")
 	t.Cleanup(assertNoError(t, func() error {
@@ -227,7 +227,7 @@ func prepZipSourceFixture(t testing.TB) string {
 
 	t.Logf("archive path: %s", archivePath)
 
-	createZipArchive(t, "zip-source", archivePrefix.Name())
+	createZipArchive(t, "zip-source", archivePrefix.Name(), false)
 
 	return archivePath
 }

internal/file/zip_read_closer.go

@@ -3,6 +3,7 @@ package file
 import (
 	"archive/zip"
 	"encoding/binary"
+	"errors"
 	"fmt"
 	"io"
 	"os"
@@ -13,7 +14,13 @@ import (
 // - https://github.com/golang/go/blob/go1.16.4/src/archive/zip/reader.go
 // findArchiveStartOffset is derived from the same stdlib utils, specifically the readDirectoryEnd function.
 
-const directoryEndLen = 22
+const (
+	directoryEndLen         = 22
+	directory64LocLen       = 20
+	directory64EndLen       = 56
+	directory64LocSignature = 0x07064b50
+	directory64EndSignature = 0x06064b50
+)
 
 // ZipReadCloser is a drop-in replacement for zip.ReadCloser (from zip.OpenReader) that additionally considers zips
 // that have bytes prefixed to the front of the archive (common with self-extracting jars).
@@ -72,6 +79,12 @@ func (b *readBuf) uint32() uint32 {
 	return v
 }
 
+func (b *readBuf) uint64() uint64 {
+	v := binary.LittleEndian.Uint64(*b)
+	*b = (*b)[8:]
+	return v
+}
+
 type directoryEnd struct {
 	diskNbr            uint32 // unused
 	dirDiskNbr         uint32 // unused
@@ -82,6 +95,7 @@ type directoryEnd struct {
 }
 
 // note: this is derived from readDirectoryEnd within the archive/zip package
+// nolint:gocognit
 func findArchiveStartOffset(r io.ReaderAt, size int64) (startOfArchive uint64, err error) {
 	// look for directoryEndSignature in the last 1k, then in the last 65k
 	var buf []byte
@@ -120,13 +134,22 @@ func findArchiveStartOffset(r io.ReaderAt, size int64) (startOfArchive uint64, e
 		directoryOffset:    uint64(b.uint32()),
 	}
 	// Calculate where the zip data actually begins
-	startOfArchive = uint64(directoryEndOffset) - d.directorySize - d.directoryOffset
 
 	// These values mean that the file can be a zip64 file
 	if d.directoryRecords == 0xffff || d.directorySize == 0xffff || d.directoryOffset == 0xffffffff {
+		p, err := findDirectory64End(r, directoryEndOffset)
+		if err == nil && p >= 0 {
+			directoryEndOffset = p
+			err = readDirectory64End(r, p, d)
+		}
+		if err != nil {
+			return 0, err
+		}
 		startOfArchive = 0 // Prefixed data not supported
 	}
 
+	startOfArchive = uint64(directoryEndOffset) - d.directorySize - d.directoryOffset
+
 	// Make sure directoryOffset points to somewhere in our file.
 	if o := int64(d.directoryOffset); o < 0 || o >= size {
 		return 0, zip.ErrFormat
@@ -134,6 +157,56 @@ func findArchiveStartOffset(r io.ReaderAt, size int64) (startOfArchive uint64, e
 	return startOfArchive, nil
 }
 
+// findDirectory64End tries to read the zip64 locator just before the
+// directory end and returns the offset of the zip64 directory end if
+// found.
+func findDirectory64End(r io.ReaderAt, directoryEndOffset int64) (int64, error) {
+	locOffset := directoryEndOffset - directory64LocLen
+	if locOffset < 0 {
+		return -1, nil // no need to look for a header outside the file
+	}
+	buf := make([]byte, directory64LocLen)
+	if _, err := r.ReadAt(buf, locOffset); err != nil {
+		return -1, err
+	}
+	b := readBuf(buf)
+	if sig := b.uint32(); sig != directory64LocSignature {
+		return -1, nil
+	}
+	if b.uint32() != 0 { // number of the disk with the start of the zip64 end of central directory
+		return -1, nil // the file is not a valid zip64-file
+	}
+	p := b.uint64()      // relative offset of the zip64 end of central directory record
+	if b.uint32() != 1 { // total number of disks
+		return -1, nil // the file is not a valid zip64-file
+	}
+	return int64(p), nil
+}
+
+// readDirectory64End reads the zip64 directory end and updates the
+// directory end with the zip64 directory end values.
+func readDirectory64End(r io.ReaderAt, offset int64, d *directoryEnd) (err error) {
+	buf := make([]byte, directory64EndLen)
+	if _, err := r.ReadAt(buf, offset); err != nil {
+		return err
+	}
+
+	b := readBuf(buf)
+	if sig := b.uint32(); sig != directory64EndSignature {
+		return errors.New("could not read directory64End")
+	}
+
+	b = b[12:]                        // skip dir size, version and version needed (uint64 + 2x uint16)
+	d.diskNbr = b.uint32()            // number of this disk
+	d.dirDiskNbr = b.uint32()         // number of the disk with the start of the central directory
+	d.dirRecordsThisDisk = b.uint64() // total number of entries in the central directory on this disk
+	d.directoryRecords = b.uint64()   // total number of entries in the central directory
+	d.directorySize = b.uint64()      // size of the central directory
+	d.directoryOffset = b.uint64()    // offset of start of central directory with respect to the starting disk number
+
+	return nil
+}
+
 func findSignatureInBlock(b []byte) int {
 	for i := len(b) - directoryEndLen; i >= 0; i-- {
 		// defined from directoryEndSignature