harden storage paths and trash handling

chfs-ng/internal/storage/storage_test.go

@@ -0,0 +1,78 @@
+package storage
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+)
+
+func TestLocalRejectsSymlinkEscapeAndAllowsNestedCreate(t *testing.T) {
+	root := t.TempDir()
+	outside := t.TempDir()
+	if err := os.WriteFile(filepath.Join(outside, "secret.txt"), []byte("secret"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.Symlink(outside, filepath.Join(root, "escape")); err != nil {
+		t.Fatal(err)
+	}
+	s := Local{Root: root}
+	if _, err := s.Open("escape/secret.txt"); err == nil {
+		t.Fatal("expected symlink escape to be rejected")
+	}
+	f, err := s.Create("a/b/c.txt")
+	if err != nil {
+		t.Fatalf("nested create failed: %v", err)
+	}
+	_ = f.Close()
+}
+
+func TestMoveToTrashPreservesRelativePathAndCleansOldEntries(t *testing.T) {
+	root := t.TempDir()
+	trash := t.TempDir()
+	s := Local{Root: root}
+	if err := os.MkdirAll(filepath.Join(root, "one", "two"), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(root, "one", "two", "same.txt"), []byte("x"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.MkdirAll(filepath.Join(trash, "old"), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	old := filepath.Join(trash, "old", "stale.txt")
+	if err := os.WriteFile(old, []byte("old"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	oldTime := time.Now().Add(-31 * 24 * time.Hour)
+	if err := os.Chtimes(old, oldTime, oldTime); err != nil {
+		t.Fatal(err)
+	}
+	if err := s.MoveToTrash("one/two/same.txt", trash); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := os.Stat(filepath.Join(trash, "one", "two", "same.txt")); err != nil {
+		t.Fatalf("trash path not preserved: %v", err)
+	}
+	if _, err := os.Stat(old); !os.IsNotExist(err) {
+		t.Fatalf("stale trash entry was not cleaned: %v", err)
+	}
+}
+
+func TestCopyPathPreservesSymlink(t *testing.T) {
+	src := filepath.Join(t.TempDir(), "link")
+	dst := filepath.Join(t.TempDir(), "link")
+	if err := os.Symlink("target", src); err != nil {
+		t.Fatal(err)
+	}
+	if err := copyPath(src, dst); err != nil {
+		t.Fatal(err)
+	}
+	got, err := os.Readlink(dst)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got != "target" {
+		t.Fatalf("got symlink target %q", got)
+	}
+}