permission: clamp Worker grants for explicit execArgv (SEMVER-MAJOR)

When the parent runs with the Permission Model, an explicit Worker execArgv
(including []) cannot drop or exceed the parent's permission-related grants.

- No worker permission flags configured → apply parent grant ceiling
- Worker permission flags set → intersect (restrict OK, escalate no)
- Rebuild permission argv from clamped options; drop space-form path tokens
- Default Worker (omit execArgv) unchanged

Signed-off-by: yunshingng <yunshingng25@gmail.com>

Author: yunshingng

doc/api/permissions.md

@@ -38,6 +38,15 @@ changes:
     description: This feature is no longer experimental.
 -->
 
+<!-- worker-execargv-permission-ceiling -->
+When the Permission Model is enabled in the parent process, creating a
+`worker_threads.Worker` with an explicit `execArgv` option (including an empty
+array) no longer allows the worker to obtain a wider permission-related grant
+set than the parent. Non-permission `execArgv` flags are unaffected. This is a
+breaking change relative to earlier releases where `execArgv: []` could drop
+the parent's Permission Model grants.
+
+
 > Stability: 2 - Stable
 
 The Node.js Permission Model is a mechanism for restricting access to specific

doc/api/worker_threads.md

@@ -1605,6 +1605,13 @@ changes:
     description: The `resourceLimits` option was introduced.
 -->
 
+<!-- worker-execargv-permission-ceiling -->
+**Permission Model (breaking):** If the parent process runs with the
+Permission Model enabled, an explicit `execArgv` (including `[]`) does not
+disable or exceed the parent's permission-related grants. See the
+[Permission Model](permissions.md#permission-model) documentation.
+
+
 * `filename` {string|URL} The path to the Worker's main script or module. Must
   be either an absolute path or a relative path (i.e. relative to the
   current working directory) starting with `./` or `../`, or a WHATWG `URL`

src/node_worker.cc

@@ -11,6 +11,7 @@
 #include "node_profiling.h"
 #include "node_snapshot_builder.h"
 #include "permission/permission.h"
+#include "path.h"
 #include "util-inl.h"
 #include "v8-cppgc.h"
 #include "v8-profiler.h"
@@ -504,6 +505,254 @@ Worker::~Worker() {
   Debug(this, "Worker %llu destroyed", thread_id_.id);
 }
 
+
+// SEMVER-MAJOR: Permission ceiling for Worker when execArgv is explicit
+// (including []). Default Worker (no execArgv) is unchanged.
+//
+// After options parse, NODE_OPTIONS and repeated --allow-* are already in
+// EnvironmentOptions. Runtime FSPermission remains authoritative for FS checks;
+// path filtering here is create-time only (prefix / exact / *).
+//
+// Parent allow-list containing "*" already means unrestricted FS for that
+// dimension; FilterPathList early-return keeps worker paths (cannot exceed *).
+
+namespace {
+
+bool WorkerConfiguredPermission(const EnvironmentOptions* w) {
+  if (w == nullptr) return false;
+  if (w->permission || w->permission_audit) return true;
+  if (!w->allow_fs_read.empty() || !w->allow_fs_write.empty()) return true;
+  return w->allow_addons || w->allow_inspector || w->allow_child_process ||
+         w->allow_net || w->allow_wasi || w->allow_ffi ||
+         w->allow_openssl_store || w->allow_worker_threads;
+}
+
+void ApplyParentPermissionCeiling(EnvironmentOptions* w,
+                                  const EnvironmentOptions* parent) {
+  w->permission = true;
+  w->permission_audit = parent->permission_audit;
+  w->allow_addons = parent->allow_addons;
+  w->allow_inspector = parent->allow_inspector;
+  w->allow_child_process = parent->allow_child_process;
+  w->allow_net = parent->allow_net;
+  w->allow_wasi = parent->allow_wasi;
+  w->allow_ffi = parent->allow_ffi;
+  w->allow_openssl_store = parent->allow_openssl_store;
+  w->allow_worker_threads = parent->allow_worker_threads;
+  w->allow_fs_read = parent->allow_fs_read;
+  w->allow_fs_write = parent->allow_fs_write;
+}
+
+void NormalizePathForCompare(std::string* s) {
+  while (s->size() > 1 &&
+         (s->back() == '/' || s->back() == static_cast<char>(92))) {
+    s->pop_back();
+  }
+#ifdef _WIN32
+  for (char& c : *s) {
+    if (c >= 'A' && c <= 'Z') {
+      c = static_cast<char>(c - 'A' + 'a');
+    }
+    if (c == '/') c = static_cast<char>(92);
+  }
+#endif
+}
+
+std::string ResolveForCompare(Environment* env, const std::string& in) {
+  if (in.empty() || in == "*") return in;
+  std::string resolved =
+      PathResolve(env, std::vector<std::string_view>{std::string_view(in)});
+  if (resolved.empty()) resolved = in;
+  NormalizePathForCompare(&resolved);
+  return resolved;
+}
+
+// Create-time filter only.
+bool PathCoveredByParentEntry(Environment* env,
+                              const std::string& parent_raw,
+                              const std::string& requested_raw) {
+  if (parent_raw == "*") return true;
+  const std::string parent = ResolveForCompare(env, parent_raw);
+  const std::string requested = ResolveForCompare(env, requested_raw);
+  if (parent.empty()) return false;
+  if (requested == parent) return true;
+  if (requested.size() <= parent.size()) return false;
+  if (requested.compare(0, parent.size(), parent) != 0) return false;
+  const char next = requested[parent.size()];
+  return next == '/' || next == static_cast<char>(92);
+}
+
+bool ParentListHasWildcard(const std::vector<std::string>& parent) {
+  for (const std::string& entry : parent) {
+    if (entry == "*") return true;
+  }
+  return false;
+}
+
+void FilterPathListToParentSubset(Environment* env,
+                                  EnvironmentOptions* w,
+                                  std::vector<std::string>* worker,
+                                  const std::vector<std::string>& parent) {
+  if (worker == nullptr) return;
+
+  // Worker enabled permission but listed no paths → keep empty (restrict).
+  if (worker->empty()) {
+    if (w->permission || w->permission_audit) return;
+    *worker = parent;
+    return;
+  }
+
+  // Parent "*" → FS already unrestricted; worker paths cannot exceed parent.
+  if (ParentListHasWildcard(parent)) return;
+
+  std::vector<std::string> out;
+  out.reserve(worker->size());
+  bool saw_star = false;
+  for (const std::string& wpath : *worker) {
+    if (wpath == "*") {
+      saw_star = true;
+      continue;
+    }
+    for (const std::string& entry : parent) {
+      if (PathCoveredByParentEntry(env, entry, wpath)) {
+        out.push_back(wpath);
+        break;
+      }
+    }
+  }
+  if (saw_star && out.empty()) {
+    *worker = parent;
+    return;
+  }
+  *worker = std::move(out);
+}
+
+void IntersectPermissionGrants(Environment* env,
+                               EnvironmentOptions* w,
+                               const EnvironmentOptions* parent) {
+  w->permission = true;
+  w->permission_audit = w->permission_audit || parent->permission_audit;
+
+  w->allow_addons = w->allow_addons && parent->allow_addons;
+  w->allow_inspector = w->allow_inspector && parent->allow_inspector;
+  w->allow_child_process =
+      w->allow_child_process && parent->allow_child_process;
+  w->allow_net = w->allow_net && parent->allow_net;
+  w->allow_wasi = w->allow_wasi && parent->allow_wasi;
+  w->allow_ffi = w->allow_ffi && parent->allow_ffi;
+  w->allow_openssl_store =
+      w->allow_openssl_store && parent->allow_openssl_store;
+  w->allow_worker_threads =
+      w->allow_worker_threads && parent->allow_worker_threads;
+
+  FilterPathListToParentSubset(env, w, &w->allow_fs_read, parent->allow_fs_read);
+  FilterPathListToParentSubset(
+      env, w, &w->allow_fs_write, parent->allow_fs_write);
+}
+
+void ClampWorkerPermissionToParent(Environment* env,
+                                   PerIsolateOptions* worker_opts) {
+  if (worker_opts == nullptr || env == nullptr ||
+      !env->permission()->enabled()) {
+    return;
+  }
+  EnvironmentOptions* parent =
+      env->isolate_data()->options()->get_per_env_options();
+  EnvironmentOptions* w = worker_opts->get_per_env_options();
+  if (parent == nullptr || w == nullptr) return;
+
+  if (!WorkerConfiguredPermission(w)) {
+    ApplyParentPermissionCeiling(w, parent);
+  } else {
+    IntersectPermissionGrants(env, w, parent);
+  }
+}
+
+// Exact flag name or flag=value (not a longer unrelated prefix).
+bool IsPermissionCliToken(const std::string& a) {
+  if (a == "--permission" || a == "--permission-audit") return true;
+  static const char* kFlags[] = {
+      "--allow-fs-read",
+      "--allow-fs-write",
+      "--allow-addons",
+      "--allow-inspector",
+      "--allow-child-process",
+      "--allow-net",
+      "--allow-wasi",
+      "--allow-ffi",
+      "--allow-openssl-store",
+      "--allow-worker",
+  };
+  for (const char* flag : kFlags) {
+    const size_t n = std::char_traits<char>::length(flag);
+    if (a == flag) return true;
+    if (a.size() > n && a.compare(0, n, flag) == 0 && a[n] == '=') return true;
+  }
+  return false;
+}
+
+bool PermissionFlagTakesNextArg(const std::string& a) {
+  return a == "--allow-fs-read" || a == "--allow-fs-write";
+}
+
+bool PathSafeForAllowFlag(const std::string& path) {
+  if (path.empty()) return false;
+  for (unsigned char c : path) {
+    if (c == 0 || c == 10 || c == 13) return false;
+  }
+  return true;
+}
+
+void RebuildExecArgvOutFromPermissionOptions(
+    PerIsolateOptions* worker_opts, std::vector<std::string>* exec_argv_out) {
+  if (worker_opts == nullptr || exec_argv_out == nullptr) return;
+  EnvironmentOptions* w = worker_opts->get_per_env_options();
+  if (w == nullptr || !w->permission) return;
+
+  std::vector<std::string> kept;
+  kept.reserve(exec_argv_out->size());
+  for (size_t i = 0; i < exec_argv_out->size(); ++i) {
+    const std::string& tok = (*exec_argv_out)[i];
+    if (tok.empty()) continue;
+    if (IsPermissionCliToken(tok)) {
+      if (PermissionFlagTakesNextArg(tok) && i + 1 < exec_argv_out->size()) {
+        const std::string& next = (*exec_argv_out)[i + 1];
+        if (!next.empty() && next[0] != '-') ++i;
+      }
+      continue;
+    }
+    kept.push_back(tok);
+  }
+
+  std::vector<std::string> out;
+  out.reserve(kept.size() + 16 + w->allow_fs_read.size() +
+              w->allow_fs_write.size());
+  for (const std::string& tok : kept) out.push_back(tok);
+
+  out.push_back("--permission");
+  if (w->permission_audit) out.push_back("--permission-audit");
+  if (w->allow_addons) out.push_back("--allow-addons");
+  if (w->allow_inspector) out.push_back("--allow-inspector");
+  if (w->allow_child_process) out.push_back("--allow-child-process");
+  if (w->allow_net) out.push_back("--allow-net");
+  if (w->allow_wasi) out.push_back("--allow-wasi");
+  if (w->allow_ffi) out.push_back("--allow-ffi");
+  if (w->allow_openssl_store) out.push_back("--allow-openssl-store");
+  if (w->allow_worker_threads) out.push_back("--allow-worker");
+  for (const std::string& p : w->allow_fs_read) {
+    if (!PathSafeForAllowFlag(p)) continue;
+    out.push_back("--allow-fs-read=" + p);
+  }
+  for (const std::string& p : w->allow_fs_write) {
+    if (!PathSafeForAllowFlag(p)) continue;
+    out.push_back("--allow-fs-write=" + p);
+  }
+  *exec_argv_out = std::move(out);
+}
+
+}  // namespace
+
+
 void Worker::New(const FunctionCallbackInfo<Value>& args) {
   Environment* env = Environment::GetCurrent(args);
   THROW_IF_INSUFFICIENT_PERMISSIONS(
@@ -683,6 +932,16 @@ void Worker::New(const FunctionCallbackInfo<Value>& args) {
     per_isolate_opts = env->isolate_data()->options()->Clone();
   }
 
+  //  
+  
+  // Explicit execArgv only (including []). Default Worker path unchanged.
+  if (env->permission()->enabled() && per_isolate_opts &&
+      args[2]->IsArray()) {
+    ClampWorkerPermissionToParent(env, per_isolate_opts.get());
+    RebuildExecArgvOutFromPermissionOptions(per_isolate_opts.get(),
+                                            &exec_argv_out);
+  }
+
   // Internal workers should not wait for inspector frontend to connect or
   // break on the first line of internal scripts. Module loader threads are
   // essential to load user codes and must not be blocked by the inspector