Adding upstream version 86.0.1.upstream/86.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 414 insertions, 0 deletions

diff --git a/js/src/vm/Compartment-inl.h b/js/src/vm/Compartment-inl.h
new file mode 100644
index 0000000000..fcf2cccdc2
--- /dev/null
+++ b/js/src/vm/Compartment-inl.h
@@ -0,0 +1,414 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef vm_Compartment_inl_h
+#define vm_Compartment_inl_h
+
+#include "vm/Compartment.h"
+
+#include <type_traits>
+
+#include "jsapi.h"
+#include "jsfriendapi.h"
+#include "jsnum.h"
+#include "gc/Barrier.h"
+#include "gc/Marking.h"
+#include "js/CallArgs.h"
+#include "js/friend/ErrorMessages.h"  // js::GetErrorMessage, JSMSG_*
+#include "js/Wrapper.h"
+#include "vm/Iteration.h"
+#include "vm/JSObject.h"
+
+#include "vm/JSContext-inl.h"
+
+struct JSClass;
+
+inline js::StringWrapperMap::Ptr JS::Compartment::lookupWrapper(
+    JSString* str) const {
+  return zone()->crossZoneStringWrappers().lookup(str);
+}
+
+inline bool JS::Compartment::wrap(JSContext* cx, JS::MutableHandleValue vp) {
+  /* Only GC things have to be wrapped or copied. */
+  if (!vp.isGCThing()) {
+    return true;
+  }
+
+  /*
+   * Symbols are GC things, but never need to be wrapped or copied because
+   * they are always allocated in the atoms zone. They still need to be
+   * marked in the new compartment's zone, however.
+   */
+  if (vp.isSymbol()) {
+    cx->markAtomValue(vp);
+    return true;
+  }
+
+  /* Handle strings. */
+  if (vp.isString()) {
+    JS::RootedString str(cx, vp.toString());
+    if (!wrap(cx, &str)) {
+      return false;
+    }
+    vp.setString(str);
+    return true;
+  }
+
+  if (vp.isBigInt()) {
+    JS::RootedBigInt bi(cx, vp.toBigInt());
+    if (!wrap(cx, &bi)) {
+      return false;
+    }
+    vp.setBigInt(bi);
+    return true;
+  }
+
+  MOZ_ASSERT(vp.isObject());
+
+  /*
+   * All that's left are objects.
+   *
+   * Object wrapping isn't the fastest thing in the world, in part because
+   * we have to unwrap and invoke the prewrap hook to find the identity
+   * object before we even start checking the cache. Neither of these
+   * operations are needed in the common case, where we're just wrapping
+   * a plain JS object from the wrappee's side of the membrane to the
+   * wrapper's side.
+   *
+   * To optimize this, we note that the cache should only ever contain
+   * identity objects - that is to say, objects that serve as the
+   * canonical representation for a unique object identity observable by
+   * script. Unwrap and prewrap are both steps that we take to get to the
+   * identity of an incoming objects, and as such, they shuld never map
+   * one identity object to another object. This means that we can safely
+   * check the cache immediately, and only risk false negatives. Do this
+   * in opt builds, and do both in debug builds so that we can assert
+   * that we get the same answer.
+   */
+#ifdef DEBUG
+  JS::AssertValueIsNotGray(vp);
+  JS::RootedObject cacheResult(cx);
+#endif
+  if (js::ObjectWrapperMap::Ptr p = lookupWrapper(&vp.toObject())) {
+#ifdef DEBUG
+    cacheResult = p->value().get();
+#else
+    vp.setObject(*p->value().get());
+    return true;
+#endif
+  }
+
+  JS::RootedObject obj(cx, &vp.toObject());
+  if (!wrap(cx, &obj)) {
+    return false;
+  }
+  vp.setObject(*obj);
+  MOZ_ASSERT_IF(cacheResult, obj == cacheResult);
+  return true;
+}
+
+inline bool JS::Compartment::wrap(JSContext* cx,
+                                  MutableHandle<mozilla::Maybe<Value>> vp) {
+  if (vp.get().isNothing()) {
+    return true;
+  }
+
+  return wrap(cx, MutableHandle<Value>::fromMarkedLocation(vp.get().ptr()));
+}
+
+namespace js {
+namespace detail {
+
+/**
+ * Return the name of class T as a static null-terminated ASCII string constant
+ * (for error messages).
+ */
+template <class T>
+const char* ClassName() {
+  return T::class_.name;
+}
+
+template <class T, class ErrorCallback>
+MOZ_MUST_USE T* UnwrapAndTypeCheckValueSlowPath(JSContext* cx,
+                                                HandleValue value,
+                                                ErrorCallback throwTypeError) {
+  JSObject* obj = nullptr;
+  if (value.isObject()) {
+    obj = &value.toObject();
+    if (IsWrapper(obj)) {
+      obj = CheckedUnwrapStatic(obj);
+      if (!obj) {
+        ReportAccessDenied(cx);
+        return nullptr;
+      }
+    }
+  }
+
+  if (!obj || !obj->is<T>()) {
+    throwTypeError();
+    return nullptr;
+  }
+
+  return &obj->as<T>();
+}
+
+template <class ErrorCallback>
+MOZ_MUST_USE JSObject* UnwrapAndTypeCheckValueSlowPath(
+    JSContext* cx, HandleValue value, const JSClass* clasp,
+    ErrorCallback throwTypeError) {
+  JSObject* obj = nullptr;
+  if (value.isObject()) {
+    obj = &value.toObject();
+    if (IsWrapper(obj)) {
+      obj = CheckedUnwrapStatic(obj);
+      if (!obj) {
+        ReportAccessDenied(cx);
+        return nullptr;
+      }
+    }
+  }
+
+  if (!obj || !obj->hasClass(clasp)) {
+    throwTypeError();
+    return nullptr;
+  }
+
+  return obj;
+}
+
+}  // namespace detail
+
+/**
+ * Remove all wrappers from `val` and try to downcast the result to class `T`.
+ *
+ * DANGER: The result may not be same-compartment with `cx`.
+ *
+ * This calls `throwTypeError` if the value isn't an object, cannot be
+ * unwrapped, or isn't an instance of the expected type. `throwTypeError` must
+ * in fact throw a TypeError (or OOM trying).
+ */
+template <class T, class ErrorCallback>
+inline MOZ_MUST_USE T* UnwrapAndTypeCheckValue(JSContext* cx, HandleValue value,
+                                               ErrorCallback throwTypeError) {
+  cx->check(value);
+
+  static_assert(!std::is_convertible_v<T*, Wrapper*>,
+                "T can't be a Wrapper type; this function discards wrappers");
+
+  if (value.isObject() && value.toObject().is<T>()) {
+    return &value.toObject().as<T>();
+  }
+
+  return detail::UnwrapAndTypeCheckValueSlowPath<T>(cx, value, throwTypeError);
+}
+
+/**
+ * Remove all wrappers from |val| and try to downcast the result to an object of
+ * the class |clasp|.
+ *
+ * DANGER: The result may not be same-compartment with |cx|.
+ *
+ * This calls |throwTypeError| if the value isn't an object, cannot be
+ * unwrapped, or isn't an instance of the expected type.  |throwTypeError| must
+ * in fact throw a TypeError (or OOM trying).
+ */
+template <class ErrorCallback>
+inline MOZ_MUST_USE JSObject* UnwrapAndTypeCheckValue(
+    JSContext* cx, HandleValue value, const JSClass* clasp,
+    ErrorCallback throwTypeError) {
+  cx->check(value);
+
+  if (value.isObject() && value.toObject().hasClass(clasp)) {
+    return &value.toObject();
+  }
+
+  return detail::UnwrapAndTypeCheckValueSlowPath(cx, value, clasp,
+                                                 throwTypeError);
+}
+
+/**
+ * Remove all wrappers from `args.thisv()` and try to downcast the result to
+ * class `T`.
+ *
+ * DANGER: The result may not be same-compartment with `cx`.
+ *
+ * This throws a TypeError if the value isn't an object, cannot be unwrapped,
+ * or isn't an instance of the expected type.
+ */
+template <class T>
+inline MOZ_MUST_USE T* UnwrapAndTypeCheckThis(JSContext* cx,
+                                              const CallArgs& args,
+                                              const char* methodName) {
+  HandleValue thisv = args.thisv();
+  return UnwrapAndTypeCheckValue<T>(cx, thisv, [cx, methodName, thisv] {
+    JS_ReportErrorNumberLatin1(cx, GetErrorMessage, nullptr,
+                               JSMSG_INCOMPATIBLE_PROTO, detail::ClassName<T>(),
+                               methodName, InformalValueTypeName(thisv));
+  });
+}
+
+/**
+ * Remove all wrappers from `args[argIndex]` and try to downcast the result to
+ * class `T`.
+ *
+ * DANGER: The result may not be same-compartment with `cx`.
+ *
+ * This throws a TypeError if the specified argument is missing, isn't an
+ * object, cannot be unwrapped, or isn't an instance of the expected type.
+ */
+template <class T>
+inline MOZ_MUST_USE T* UnwrapAndTypeCheckArgument(JSContext* cx, CallArgs& args,
+                                                  const char* methodName,
+                                                  int argIndex) {
+  HandleValue val = args.get(argIndex);
+  return UnwrapAndTypeCheckValue<T>(cx, val, [cx, val, methodName, argIndex] {
+    ToCStringBuf cbuf;
+    if (char* numStr = NumberToCString(cx, &cbuf, argIndex + 1, 10)) {
+      JS_ReportErrorNumberLatin1(
+          cx, GetErrorMessage, nullptr, JSMSG_WRONG_TYPE_ARG, numStr,
+          methodName, detail::ClassName<T>(), InformalValueTypeName(val));
+    } else {
+      ReportOutOfMemory(cx);
+    }
+  });
+}
+
+/**
+ * Unwrap an object of a known type.
+ *
+ * If `obj` is an object of class T, this returns a pointer to that object. If
+ * `obj` is a wrapper for such an object, this tries to unwrap the object and
+ * return a pointer to it. If access is denied, or `obj` was a wrapper but has
+ * been nuked, this reports an error and returns null.
+ *
+ * In all other cases, the behavior is undefined, so call this only if `obj` is
+ * known to have been an object of class T, or a wrapper to a T, at some point.
+ */
+template <class T>
+inline MOZ_MUST_USE T* UnwrapAndDowncastObject(JSContext* cx, JSObject* obj) {
+  static_assert(!std::is_convertible_v<T*, Wrapper*>,
+                "T can't be a Wrapper type; this function discards wrappers");
+
+  if (IsProxy(obj)) {
+    if (JS_IsDeadWrapper(obj)) {
+      JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr,
+                                JSMSG_DEAD_OBJECT);
+      return nullptr;
+    }
+
+    // It would probably be OK to do an unchecked unwrap here, but we allow
+    // arbitrary security policies, so check anyway.
+    obj = obj->maybeUnwrapAs<T>();
+    if (!obj) {
+      ReportAccessDenied(cx);
+      return nullptr;
+    }
+  }
+
+  return &obj->as<T>();
+}
+
+/**
+ * Unwrap an object of a known (but not compile-time-known) class.
+ *
+ * If |obj| is an object with class |clasp|, this returns |obj|.  If |obj| is a
+ * wrapper for such an object, this tries to unwrap the object and return a
+ * pointer to it.  If access is denied, or |obj| was a wrapper but has been
+ * nuked, this reports an error and returns null.
+ *
+ * In all other cases, the behavior is undefined, so call this only if |obj| is
+ * known to have had class |clasp|, or been a wrapper to such an object, at some
+ * point.
+ */
+inline MOZ_MUST_USE JSObject* UnwrapAndDowncastObject(JSContext* cx,
+                                                      JSObject* obj,
+                                                      const JSClass* clasp) {
+  if (IsProxy(obj)) {
+    if (JS_IsDeadWrapper(obj)) {
+      JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr,
+                                JSMSG_DEAD_OBJECT);
+      return nullptr;
+    }
+
+    // It would probably be OK to do an unchecked unwrap here, but we allow
+    // arbitrary security policies, so check anyway.
+    obj = obj->maybeUnwrapAs(clasp);
+    if (!obj) {
+      ReportAccessDenied(cx);
+      return nullptr;
+    }
+  }
+
+  MOZ_ASSERT(obj->hasClass(clasp));
+  return obj;
+}
+
+/**
+ * Unwrap a value of a known type. See UnwrapAndDowncastObject.
+ */
+template <class T>
+inline MOZ_MUST_USE T* UnwrapAndDowncastValue(JSContext* cx,
+                                              const Value& value) {
+  return UnwrapAndDowncastObject<T>(cx, &value.toObject());
+}
+
+/**
+ * Unwrap an object of a known (but not compile-time-known) class.  See
+ * UnwrapAndDowncastObject.
+ */
+inline MOZ_MUST_USE JSObject* UnwrapAndDowncastValue(JSContext* cx,
+                                                     const Value& value,
+                                                     const JSClass* clasp) {
+  return UnwrapAndDowncastObject(cx, &value.toObject(), clasp);
+}
+
+/**
+ * Read a private slot that is known to point to a particular type of object.
+ *
+ * Some internal slots specified in various standards effectively have static
+ * types. For example, the [[ownerReadableStream]] slot of a stream reader is
+ * guaranteed to be a ReadableStream. However, because of compartments, we
+ * sometimes store a cross-compartment wrapper in that slot. And since wrappers
+ * can be nuked, that wrapper may become a dead object proxy.
+ *
+ * UnwrapInternalSlot() copes with the cross-compartment and dead object cases,
+ * but not plain bugs where the slot hasn't been initialized or doesn't contain
+ * the expected type of object. Call this only if the slot is certain to
+ * contain either an instance of T, a wrapper for a T, or a dead object.
+ *
+ * `cx` and `unwrappedObj` are not required to be same-compartment.
+ *
+ * DANGER: The result may not be same-compartment with either `cx` or `obj`.
+ */
+template <class T>
+inline MOZ_MUST_USE T* UnwrapInternalSlot(JSContext* cx,
+                                          Handle<NativeObject*> unwrappedObj,
+                                          uint32_t slot) {
+  static_assert(!std::is_convertible_v<T*, Wrapper*>,
+                "T can't be a Wrapper type; this function discards wrappers");
+
+  return UnwrapAndDowncastValue<T>(cx, unwrappedObj->getFixedSlot(slot));
+}
+
+/**
+ * Read a function slot that is known to point to a particular type of object.
+ *
+ * This is like UnwrapInternalSlot, but for extended function slots. Call this
+ * only if the specified slot is known to have been initialized with an object
+ * of class T or a wrapper for such an object.
+ *
+ * DANGER: The result may not be same-compartment with `cx`.
+ */
+template <class T>
+MOZ_MUST_USE T* UnwrapCalleeSlot(JSContext* cx, CallArgs& args,
+                                 size_t extendedSlot) {
+  JSFunction& func = args.callee().as<JSFunction>();
+  return UnwrapAndDowncastValue<T>(cx, func.getExtendedSlot(extendedSlot));
+}
+
+}  // namespace js
+
+#endif /* vm_Compartment_inl_h */