michael@0: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
michael@0: /* vim: set ts=8 sts=4 et sw=4 tw=99: */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: /* Implement global service to track stack of JSContext. */
michael@0: 
michael@0: #include "xpcprivate.h"
michael@0: #include "XPCWrapper.h"
michael@0: #include "nsDOMJSUtils.h"
michael@0: #include "nsNullPrincipal.h"
michael@0: #include "mozilla/dom/BindingUtils.h"
michael@0: 
michael@0: using namespace mozilla;
michael@0: using namespace JS;
michael@0: using namespace xpc;
michael@0: using mozilla::dom::DestroyProtoAndIfaceCache;
michael@0: 
michael@0: /***************************************************************************/
michael@0: 
michael@0: XPCJSContextStack::~XPCJSContextStack()
michael@0: {
michael@0:     if (mSafeJSContext) {
michael@0:         mSafeJSContextGlobal = nullptr;
michael@0:         JS_DestroyContextNoGC(mSafeJSContext);
michael@0:         mSafeJSContext = nullptr;
michael@0:     }
michael@0: }
michael@0: 
michael@0: JSContext*
michael@0: XPCJSContextStack::Pop()
michael@0: {
michael@0:     MOZ_ASSERT(!mStack.IsEmpty());
michael@0: 
michael@0:     uint32_t idx = mStack.Length() - 1; // The thing we're popping
michael@0: 
michael@0:     JSContext *cx = mStack[idx].cx;
michael@0: 
michael@0:     mStack.RemoveElementAt(idx);
michael@0:     if (idx == 0) {
michael@0:         js::Debug_SetActiveJSContext(mRuntime->Runtime(), nullptr);
michael@0:         return cx;
michael@0:     }
michael@0: 
michael@0:     --idx; // Advance to new top of the stack
michael@0: 
michael@0:     XPCJSContextInfo &e = mStack[idx];
michael@0:     if (e.cx && e.savedFrameChain) {
michael@0:         // Pop() can be called outside any request for e.cx.
michael@0:         JSAutoRequest ar(e.cx);
michael@0:         JS_RestoreFrameChain(e.cx);
michael@0:         e.savedFrameChain = false;
michael@0:     }
michael@0:     js::Debug_SetActiveJSContext(mRuntime->Runtime(), e.cx);
michael@0:     return cx;
michael@0: }
michael@0: 
michael@0: bool
michael@0: XPCJSContextStack::Push(JSContext *cx)
michael@0: {
michael@0:     js::Debug_SetActiveJSContext(mRuntime->Runtime(), cx);
michael@0:     if (mStack.Length() == 0) {
michael@0:         mStack.AppendElement(cx);
michael@0:         return true;
michael@0:     }
michael@0: 
michael@0:     XPCJSContextInfo &e = mStack[mStack.Length() - 1];
michael@0:     if (e.cx) {
michael@0:         // The cx we're pushing is also stack-top. In general we still need to
michael@0:         // call JS_SaveFrameChain here. But if that would put us in a
michael@0:         // compartment that's same-origin with the current one, we can skip it.
michael@0:         nsIScriptSecurityManager* ssm = XPCWrapper::GetSecurityManager();
michael@0:         if ((e.cx == cx) && ssm) {
michael@0:             // DOM JSContexts don't store their default compartment object on
michael@0:             // the cx, so in those cases we need to fetch it via the scx
michael@0:             // instead. And in some cases (i.e. the SafeJSContext), we have no
michael@0:             // default compartment object at all.
michael@0:             RootedObject defaultScope(cx, GetDefaultScopeFromJSContext(cx));
michael@0:             if (defaultScope) {
michael@0:                 nsIPrincipal *currentPrincipal =
michael@0:                   GetCompartmentPrincipal(js::GetContextCompartment(cx));
michael@0:                 nsIPrincipal *defaultPrincipal = GetObjectPrincipal(defaultScope);
michael@0:                 if (currentPrincipal->Equals(defaultPrincipal)) {
michael@0:                     mStack.AppendElement(cx);
michael@0:                     return true;
michael@0:                 }
michael@0:             }
michael@0:         }
michael@0: 
michael@0:         {
michael@0:             // Push() can be called outside any request for e.cx.
michael@0:             JSAutoRequest ar(e.cx);
michael@0:             if (!JS_SaveFrameChain(e.cx))
michael@0:                 return false;
michael@0:             e.savedFrameChain = true;
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     mStack.AppendElement(cx);
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: bool
michael@0: XPCJSContextStack::HasJSContext(JSContext *cx)
michael@0: {
michael@0:     for (uint32_t i = 0; i < mStack.Length(); i++)
michael@0:         if (cx == mStack[i].cx)
michael@0:             return true;
michael@0:     return false;
michael@0: }
michael@0: 
michael@0: static bool
michael@0: SafeGlobalResolve(JSContext *cx, HandleObject obj, HandleId id)
michael@0: {
michael@0:     bool resolved;
michael@0:     return JS_ResolveStandardClass(cx, obj, id, &resolved);
michael@0: }
michael@0: 
michael@0: static void
michael@0: SafeFinalize(JSFreeOp *fop, JSObject* obj)
michael@0: {
michael@0:     SandboxPrivate* sop =
michael@0:         static_cast<SandboxPrivate*>(xpc_GetJSPrivate(obj));
michael@0:     sop->ForgetGlobalObject();
michael@0:     NS_IF_RELEASE(sop);
michael@0:     DestroyProtoAndIfaceCache(obj);
michael@0: }
michael@0: 
michael@0: const JSClass xpc::SafeJSContextGlobalClass = {
michael@0:     "global_for_XPCJSContextStack_SafeJSContext",
michael@0:     XPCONNECT_GLOBAL_FLAGS,
michael@0:     JS_PropertyStub, JS_DeletePropertyStub, JS_PropertyStub, JS_StrictPropertyStub,
michael@0:     JS_EnumerateStub, SafeGlobalResolve, JS_ConvertStub, SafeFinalize,
michael@0:     nullptr, nullptr, nullptr, JS_GlobalObjectTraceHook
michael@0: };
michael@0: 
michael@0: JSContext*
michael@0: XPCJSContextStack::GetSafeJSContext()
michael@0: {
michael@0:     MOZ_ASSERT(mSafeJSContext);
michael@0:     return mSafeJSContext;
michael@0: }
michael@0: 
michael@0: JSObject*
michael@0: XPCJSContextStack::GetSafeJSContextGlobal()
michael@0: {
michael@0:     MOZ_ASSERT(mSafeJSContextGlobal);
michael@0:     return mSafeJSContextGlobal;
michael@0: }
michael@0: 
michael@0: JSContext*
michael@0: XPCJSContextStack::InitSafeJSContext()
michael@0: {
michael@0:     MOZ_ASSERT(!mSafeJSContext);
michael@0: 
michael@0:     // Start by getting the principal holder and principal for this
michael@0:     // context.  If we can't manage that, don't bother with the rest.
michael@0:     nsRefPtr<nsNullPrincipal> principal = new nsNullPrincipal();
michael@0:     nsresult rv = principal->Init();
michael@0:     if (NS_FAILED(rv))
michael@0:         MOZ_CRASH();
michael@0: 
michael@0:     nsXPConnect* xpc = nsXPConnect::XPConnect();
michael@0:     JSRuntime *rt = xpc->GetRuntime()->Runtime();
michael@0:     if (!rt)
michael@0:         MOZ_CRASH();
michael@0: 
michael@0:     mSafeJSContext = JS_NewContext(rt, 8192);
michael@0:     if (!mSafeJSContext)
michael@0:         MOZ_CRASH();
michael@0:     JSAutoRequest req(mSafeJSContext);
michael@0:     ContextOptionsRef(mSafeJSContext).setNoDefaultCompartmentObject(true);
michael@0: 
michael@0:     JS_SetErrorReporter(mSafeJSContext, xpc::SystemErrorReporter);
michael@0: 
michael@0:     JS::CompartmentOptions options;
michael@0:     options.setZone(JS::SystemZone)
michael@0:            .setTrace(TraceXPCGlobal);
michael@0:     mSafeJSContextGlobal = CreateGlobalObject(mSafeJSContext,
michael@0:                                               &SafeJSContextGlobalClass,
michael@0:                                               principal, options);
michael@0:     if (!mSafeJSContextGlobal)
michael@0:         MOZ_CRASH();
michael@0: 
michael@0:     // Note: make sure to set the private before calling
michael@0:     // InitClasses
michael@0:     nsRefPtr<SandboxPrivate> sp = new SandboxPrivate(principal, mSafeJSContextGlobal);
michael@0:     JS_SetPrivate(mSafeJSContextGlobal, sp.forget().take());
michael@0: 
michael@0:     // After this point either glob is null and the
michael@0:     // nsIScriptObjectPrincipal ownership is either handled by the
michael@0:     // nsCOMPtr or dealt with, or we'll release in the finalize
michael@0:     // hook.
michael@0:     if (NS_FAILED(xpc->InitClasses(mSafeJSContext, mSafeJSContextGlobal)))
michael@0:         MOZ_CRASH();
michael@0: 
michael@0:     JS::RootedObject glob(mSafeJSContext, mSafeJSContextGlobal);
michael@0:     JS_FireOnNewGlobalObject(mSafeJSContext, glob);
michael@0: 
michael@0:     return mSafeJSContext;
michael@0: }