webFileBrowser/internal/browser/file_test.go

package browser

import (
	"errors"
	"io"
	"os"
	"path/filepath"
	"testing"

	"webfilebrowser/internal/config"
)

func TestOpenFileReturnsOnlyARegularFileWithinTheConfiguredRoot(t *testing.T) {
	rootPath := t.TempDir()
	contents := []byte("byte-identical download")
	if err := os.WriteFile(filepath.Join(rootPath, "report.txt"), contents, 0o600); err != nil {
		t.Fatal(err)
	}
	browser, err := New([]config.Root{{Name: "Media", Path: rootPath}})
	if err != nil {
		t.Fatal(err)
	}

	file, metadata, err := browser.OpenFile("Media", "report.txt")
	if err != nil {
		t.Fatalf("OpenFile() error = %v", err)
	}
	t.Cleanup(func() { _ = file.Close() })
	actual, err := io.ReadAll(file)
	if err != nil {
		t.Fatal(err)
	}
	if string(actual) != string(contents) {
		t.Errorf("OpenFile() bytes = %q, want %q", actual, contents)
	}
	if metadata.Name != "report.txt" || metadata.Size != int64(len(contents)) {
		t.Errorf("OpenFile() metadata = %#v, want report.txt with its byte size", metadata)
	}
}

func TestOpenFileRejectsTraversalAndSymlinkEscapes(t *testing.T) {
	rootPath := t.TempDir()
	outsidePath := t.TempDir()
	if err := os.WriteFile(filepath.Join(outsidePath, "secret.txt"), []byte("outside-root"), 0o600); err != nil {
		t.Fatal(err)
	}
	if err := os.Symlink(filepath.Join(outsidePath, "secret.txt"), filepath.Join(rootPath, "escape.txt")); err != nil {
		t.Fatal(err)
	}
	browser, err := New([]config.Root{{Name: "Media", Path: rootPath}})
	if err != nil {
		t.Fatal(err)
	}

	for _, relativePath := range []string{"../" + filepath.Base(outsidePath) + "/secret.txt", "escape.txt"} {
		t.Run(relativePath, func(t *testing.T) {
			if _, _, err := browser.OpenFile("Media", relativePath); !errors.Is(err, ErrPathOutsideRoot) {
				t.Errorf("OpenFile(%q) error = %v, want ErrPathOutsideRoot", relativePath, err)
			}
		})
	}
}