Validate archive member paths before extraction (#9820)

Signed-off-by: massy-o <telitos000@gmail.com>

pkg/utils/untar.go

@@ -1,9 +1,13 @@
 package utils
 
 import (
+	"archive/tar"
 	"fmt"
 	"os"
+	"path/filepath"
+	"strings"
 
+	"github.com/klauspost/compress/zip"
 	"github.com/mholt/archiver/v3"
 )
 
@@ -54,7 +58,15 @@ func ExtractArchive(archive, dst string) error {
 		v.Tar = mytar
 	}
 
+	extractRoot, err := filepath.Abs(dst)
+	if err != nil {
+		return err
+	}
+
 	err = archiver.Walk(archive, func(f archiver.File) error {
+		if err := validateArchiveMemberPath(extractRoot, archiveMemberName(f)); err != nil {
+			return err
+		}
 		if f.FileInfo.Mode()&os.ModeSymlink != 0 {
 			return fmt.Errorf("archive contains a symlink")
 		}
@@ -67,3 +79,41 @@ func ExtractArchive(archive, dst string) error {
 
 	return un.Unarchive(archive, dst)
 }
+
+func archiveMemberName(f archiver.File) string {
+	switch h := f.Header.(type) {
+	case tar.Header:
+		return h.Name
+	case *tar.Header:
+		return h.Name
+	case zip.FileHeader:
+		return h.Name
+	case *zip.FileHeader:
+		return h.Name
+	default:
+		return f.Name()
+	}
+}
+
+func validateArchiveMemberPath(root, name string) error {
+	if name == "" {
+		return fmt.Errorf("archive contains an empty path")
+	}
+
+	normalizedName := filepath.FromSlash(strings.ReplaceAll(name, "\\", "/"))
+	cleanedName := filepath.Clean(normalizedName)
+	if filepath.IsAbs(cleanedName) || cleanedName == ".." || strings.HasPrefix(cleanedName, ".."+string(os.PathSeparator)) {
+		return fmt.Errorf("archive contains an unsafe path: %s", name)
+	}
+
+	targetPath := filepath.Join(root, cleanedName)
+	relativePath, err := filepath.Rel(root, targetPath)
+	if err != nil {
+		return err
+	}
+	if relativePath == ".." || strings.HasPrefix(relativePath, ".."+string(os.PathSeparator)) || filepath.IsAbs(relativePath) {
+		return fmt.Errorf("archive contains an unsafe path: %s", name)
+	}
+
+	return nil
+}

pkg/utils/untar_test.go

@@ -0,0 +1,128 @@
+package utils_test
+
+import (
+	"archive/tar"
+	"archive/zip"
+	"os"
+	"path/filepath"
+
+	. "github.com/mudler/LocalAI/pkg/utils"
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("utils/archive tests", func() {
+	It("extracts regular nested zip members", func() {
+		tmpDir := GinkgoT().TempDir()
+		archivePath := filepath.Join(tmpDir, "model.zip")
+		extractPath := filepath.Join(tmpDir, "models")
+
+		Expect(writeZipArchive(archivePath, map[string]string{
+			"nested/model.yaml": "name: test",
+		})).To(Succeed())
+
+		Expect(ExtractArchive(archivePath, extractPath)).To(Succeed())
+
+		extracted, err := os.ReadFile(filepath.Join(extractPath, "nested", "model.yaml"))
+		Expect(err).ToNot(HaveOccurred())
+		Expect(string(extracted)).To(Equal("name: test"))
+	})
+
+	It("rejects zip members that escape the destination", func() {
+		tmpDir := GinkgoT().TempDir()
+		archivePath := filepath.Join(tmpDir, "model.zip")
+		extractPath := filepath.Join(tmpDir, "models")
+
+		Expect(writeZipArchive(archivePath, map[string]string{
+			"../escaped.txt": "escaped",
+		})).To(Succeed())
+
+		err := ExtractArchive(archivePath, extractPath)
+
+		Expect(err).To(HaveOccurred())
+		Expect(err.Error()).To(ContainSubstring("unsafe path"))
+		Expect(filepath.Join(tmpDir, "escaped.txt")).ToNot(BeAnExistingFile())
+	})
+
+	It("rejects tar members that escape the destination", func() {
+		tmpDir := GinkgoT().TempDir()
+		archivePath := filepath.Join(tmpDir, "model.tar")
+		extractPath := filepath.Join(tmpDir, "models")
+
+		Expect(writeTarArchive(archivePath, map[string]string{
+			"../escaped.txt": "escaped",
+		})).To(Succeed())
+
+		err := ExtractArchive(archivePath, extractPath)
+
+		Expect(err).To(HaveOccurred())
+		Expect(err.Error()).To(ContainSubstring("unsafe path"))
+		Expect(filepath.Join(tmpDir, "escaped.txt")).ToNot(BeAnExistingFile())
+	})
+})
+
+func writeZipArchive(path string, files map[string]string) (err error) {
+	out, err := os.Create(path)
+	if err != nil {
+		return err
+	}
+	defer func() {
+		if closeErr := out.Close(); err == nil {
+			err = closeErr
+		}
+	}()
+
+	writer := zip.NewWriter(out)
+	defer func() {
+		if closeErr := writer.Close(); err == nil {
+			err = closeErr
+		}
+	}()
+
+	for name, contents := range files {
+		fileWriter, err := writer.Create(name)
+		if err != nil {
+			return err
+		}
+		if _, err := fileWriter.Write([]byte(contents)); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func writeTarArchive(path string, files map[string]string) (err error) {
+	out, err := os.Create(path)
+	if err != nil {
+		return err
+	}
+	defer func() {
+		if closeErr := out.Close(); err == nil {
+			err = closeErr
+		}
+	}()
+
+	writer := tar.NewWriter(out)
+	defer func() {
+		if closeErr := writer.Close(); err == nil {
+			err = closeErr
+		}
+	}()
+
+	for name, contents := range files {
+		data := []byte(contents)
+		if err := writer.WriteHeader(&tar.Header{
+			Name: name,
+			Mode: 0o600,
+			Size: int64(len(data)),
+		}); err != nil {
+			return err
+		}
+		if _, err := writer.Write(data); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}