fix: tar without compression

Author: Skarlso

pkg/providers/gogit/git.go

@@ -5,15 +5,12 @@
 package gogit
 
 import (
-	"compress/gzip"
 	"context"
-	"errors"
 	"fmt"
 	"os"
 	"path/filepath"
 	"time"
 
-	"github.com/fluxcd/pkg/tar"
 	"github.com/go-git/go-git/v5"
 	"github.com/go-git/go-git/v5/plumbing"
 	"github.com/go-git/go-git/v5/plumbing/object"
@@ -99,8 +96,8 @@ func (g *Git) Push(ctx context.Context, opts *pkg.PushOptions) (string, error) {
 
 	// we only care about the error if it is NOT a header error. Otherwise, we assume the content
 	// wasn't compressed.
-	if err = tar.Untar(blob, dir, tar.WithMaxUntarSize(-1)); err != nil && !errors.Is(err, gzip.ErrHeader) {
-		return "", fmt.Errorf("failed to untar first layer: %w", err)
+	if err = Untar(blob, dir); err != nil {
+		return "", fmt.Errorf("failed to untar content: %w", err)
 	}
 
 	// Add all extracted files.

pkg/providers/gogit/tar.go

@@ -0,0 +1,52 @@
+package gogit
+
+import (
+	"archive/tar"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+
+	"github.com/mandelsoft/vfs/pkg/vfs"
+)
+
+// Untar writes a tar stream to a filesystem.
+func Untar(in io.Reader, dir string) error {
+	tr := tar.NewReader(in)
+	for {
+		header, err := tr.Next()
+		if err != nil {
+			if errors.Is(err, io.EOF) {
+				return nil
+			}
+			return err
+		}
+
+		abs := filepath.Join(dir, header.Name)
+
+		switch header.Typeflag {
+		case tar.TypeDir:
+			if err := os.MkdirAll(abs, vfs.FileMode(header.Mode)); err != nil {
+				return fmt.Errorf("unable to create directory %s: %w", header.Name, err)
+			}
+		case tar.TypeReg:
+			file, err := os.OpenFile(abs, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, vfs.FileMode(header.Mode))
+			if err != nil {
+				return fmt.Errorf("unable to open file %s: %w", header.Name, err)
+			}
+			//nolint:gosec // We don't know what size limit we could set, the tar
+			// archive can be an image layer and that can even reach the gigabyte range.
+			// For now, we acknowledge the risk.
+			//
+			// We checked other softwares and tried to figure out how they manage this,
+			// but it's handled the same way.
+			if _, err := io.Copy(file, tr); err != nil {
+				return fmt.Errorf("unable to copy tar file to filesystem: %w", err)
+			}
+			if err := file.Close(); err != nil {
+				return fmt.Errorf("unable to close file %s: %w", header.Name, err)
+			}
+		}
+	}
+}