From 999365b34d0bc5e50b670386c98111025a37997a Mon Sep 17 00:00:00 2001
From: Matthew Burket <mburket@redhat.com>
Date: Fri, 1 May 2026 10:22:21 -0500
Subject: [PATCH] Fix possible zipslip in image/docker.go

Created with Cursor
---
 image/docker.go      |  8 +++++++-
 image/docker_test.go | 37 +++++++++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+), 1 deletion(-)

diff --git a/image/docker.go b/image/docker.go
index d3e26ff..18a9d4b 100644
--- a/image/docker.go
+++ b/image/docker.go
@@ -42,7 +42,13 @@ func NewDockerLocalImage(ctx context.Context, exportDir string, importDir string
 	tr := tar.NewReader(f)
 	hdr, err := tr.Next()
 	for ; err == nil; hdr, err = tr.Next() {
-		dir, fn := filepath.Split(hdr.Name)
+		// Docker export tar entries use slash-separated names; reject Tar Slip paths.
+		cleanName := filepath.Clean(filepath.FromSlash(hdr.Name))
+		if !filepath.IsLocal(cleanName) {
+			return nil, fmt.Errorf("invalid tar entry path %q", hdr.Name)
+		}
+
+		dir, fn := filepath.Split(cleanName)
 
 		if strings.HasSuffix(fn, ".tar") {
 			layerFilePath := ""
diff --git a/image/docker_test.go b/image/docker_test.go
index 920de13..4c4b7f8 100644
--- a/image/docker_test.go
+++ b/image/docker_test.go
@@ -1,9 +1,11 @@
 package image
 
 import (
+	"archive/tar"
 	"context"
 	"fmt"
 	"os"
+	"path/filepath"
 	"testing"
 )
 
@@ -26,3 +28,38 @@ func TestFromExported(t *testing.T) {
 	}
 	fmt.Println(di)
 }
+
+func TestNewDockerLocalImage_rejectsTarSlipPaths(t *testing.T) {
+	tmp := t.TempDir()
+	tarPath := filepath.Join(tmp, "export.tar")
+	f, err := os.Create(tarPath)
+	if err != nil {
+		t.Fatal(err)
+	}
+	tw := tar.NewWriter(f)
+	hdr := &tar.Header{
+		Name:     "../../../outside/evil.tar",
+		Mode:     0600,
+		Size:     0,
+		Typeflag: tar.TypeReg,
+	}
+	if err := tw.WriteHeader(hdr); err != nil {
+		t.Fatal(err)
+	}
+	if err := tw.Close(); err != nil {
+		t.Fatal(err)
+	}
+	if err := f.Close(); err != nil {
+		t.Fatal(err)
+	}
+
+	importDir := filepath.Join(tmp, "import")
+	if err := os.MkdirAll(importDir, 0700); err != nil {
+		t.Fatal(err)
+	}
+
+	_, err = NewDockerLocalImage(context.Background(), tarPath, importDir)
+	if err == nil {
+		t.Fatal("expected error for path traversal in tar entry name")
+	}
+}