fix: harden filesystem trust boundaries

tools/scripts/tests/copy_security.test.js

@@ -0,0 +1,53 @@
+const assert = require("assert");
+const fs = require("fs");
+const os = require("os");
+const path = require("path");
+
+const { copyRecursiveSync } = require("../../bin/install");
+
+async function main() {
+  const { copyFolderSync } = await import("../../scripts/setup_web.js");
+
+  const root = fs.mkdtempSync(path.join(os.tmpdir(), "copy-security-"));
+  try {
+    const safeRoot = path.join(root, "safe-root");
+    const destRoot = path.join(root, "dest-root");
+    const outsideDir = path.join(root, "outside");
+
+    fs.mkdirSync(path.join(safeRoot, "nested"), { recursive: true });
+    fs.mkdirSync(outsideDir, { recursive: true });
+
+    fs.writeFileSync(path.join(safeRoot, "nested", "ok.txt"), "ok");
+    fs.writeFileSync(path.join(outsideDir, "secret.txt"), "secret");
+    fs.symlinkSync(outsideDir, path.join(safeRoot, "escape-link"));
+
+    copyRecursiveSync(safeRoot, path.join(destRoot, "install-copy"), safeRoot);
+    copyFolderSync(safeRoot, path.join(destRoot, "web-copy"), safeRoot);
+
+    assert.strictEqual(
+      fs.existsSync(path.join(destRoot, "install-copy", "escape-link", "secret.txt")),
+      false,
+      "installer copy must not follow symlinks outside the cloned root",
+    );
+    assert.strictEqual(
+      fs.existsSync(path.join(destRoot, "web-copy", "escape-link", "secret.txt")),
+      false,
+      "web setup copy must not follow symlinks outside the skills root",
+    );
+    assert.strictEqual(
+      fs.readFileSync(path.join(destRoot, "install-copy", "nested", "ok.txt"), "utf8"),
+      "ok",
+    );
+    assert.strictEqual(
+      fs.readFileSync(path.join(destRoot, "web-copy", "nested", "ok.txt"), "utf8"),
+      "ok",
+    );
+  } finally {
+    fs.rmSync(root, { recursive: true, force: true });
+  }
+}
+
+main().catch((error) => {
+  console.error(error);
+  process.exit(1);
+});