diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
---|---|---|
committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
commit | 36d22d82aa202bb199967e9512281e9a53db42c9 (patch) | |
tree | 105e8c98ddea1c1e4784a60a5a6410fa416be2de /testing/specialpowers/content/WrapPrivileged.sys.mjs | |
parent | Initial commit. (diff) | |
download | firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.tar.xz firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.zip |
Adding upstream version 115.7.0esr.upstream/115.7.0esr
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'testing/specialpowers/content/WrapPrivileged.sys.mjs')
-rw-r--r-- | testing/specialpowers/content/WrapPrivileged.sys.mjs | 385 |
1 files changed, 385 insertions, 0 deletions
diff --git a/testing/specialpowers/content/WrapPrivileged.sys.mjs b/testing/specialpowers/content/WrapPrivileged.sys.mjs new file mode 100644 index 0000000000..5fe67a94e2 --- /dev/null +++ b/testing/specialpowers/content/WrapPrivileged.sys.mjs @@ -0,0 +1,385 @@ +/* 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/. */ + +/** + * This module handles wrapping privileged objects so that they can be exposed + * to unprivileged contexts. It is only to be used in automated tests. + * + * Its exact semantics are also liable to change at any time, so any callers + * relying on undocumented behavior or subtle platform features should expect + * breakage. Those callers should, wherever possible, migrate to fully + * chrome-privileged scripts when they need to interact with privileged APIs. + */ + +// XPCNativeWrapper is not defined globally in ESLint as it may be going away. +// See bug 1481337. +/* globals XPCNativeWrapper */ + +Cu.crashIfNotInAutomation(); + +let wrappedObjects = new WeakMap(); +let perWindowInfo = new WeakMap(); +let noAutoWrap = new WeakSet(); + +function isWrappable(x) { + if (typeof x === "object") { + return x !== null; + } + return typeof x === "function"; +} + +function isWrapper(x) { + try { + return isWrappable(x) && wrappedObjects.has(x); + } catch (e) { + // If `x` is a remote object proxy, trying to access an unexpected property + // on it will throw a security error, even though we're chrome privileged. + // However, remote proxies are not SpecialPowers wrappers, so: + return false; + } +} + +function unwrapIfWrapped(x) { + return isWrapper(x) ? unwrapPrivileged(x) : x; +} + +function wrapIfUnwrapped(x, w) { + return isWrapper(x) ? x : wrapPrivileged(x, w); +} + +function isObjectOrArray(obj) { + if (Object(obj) !== obj) { + return false; + } + let arrayClasses = [ + "Object", + "Array", + "Int8Array", + "Uint8Array", + "Int16Array", + "Uint16Array", + "Int32Array", + "Uint32Array", + "Float32Array", + "Float64Array", + "Uint8ClampedArray", + ]; + let className = Cu.getClassName(obj, true); + return arrayClasses.includes(className); +} + +// In general, we want Xray wrappers for content DOM objects, because waiving +// Xray gives us Xray waiver wrappers that clamp the principal when we cross +// compartment boundaries. However, there are some exceptions where we want +// to use a waiver: +// +// * Xray adds some gunk to toString(), which has the potential to confuse +// consumers that aren't expecting Xray wrappers. Since toString() is a +// non-privileged method that returns only strings, we can just waive Xray +// for that case. +// +// * We implement Xrays to pure JS [[Object]] and [[Array]] instances that +// filter out tricky things like callables. This is the right thing for +// security in general, but tends to break tests that try to pass object +// literals into SpecialPowers. So we waive [[Object]] and [[Array]] +// instances before inspecting properties. +// +// * When we don't have meaningful Xray semantics, we create an Opaque +// XrayWrapper for security reasons. For test code, we generally want to see +// through that sort of thing. +function waiveXraysIfAppropriate(obj, propName) { + if ( + propName == "toString" || + isObjectOrArray(obj) || + /Opaque/.test(Object.prototype.toString.call(obj)) + ) { + return XPCNativeWrapper.unwrap(obj); + } + return obj; +} + +// We can't call apply() directy on Xray-wrapped functions, so we have to be +// clever. +function doApply(fun, invocant, args) { + // We implement Xrays to pure JS [[Object]] instances that filter out tricky + // things like callables. This is the right thing for security in general, + // but tends to break tests that try to pass object literals into + // SpecialPowers. So we waive [[Object]] instances when they're passed to a + // SpecialPowers-wrapped callable. + // + // Note that the transitive nature of Xray waivers means that any property + // pulled off such an object will also be waived, and so we'll get principal + // clamping for Xrayed DOM objects reached from literals, so passing things + // like {l : xoWin.location} won't work. Hopefully the rabbit hole doesn't + // go that deep. + args = args.map(x => (isObjectOrArray(x) ? Cu.waiveXrays(x) : x)); + return Reflect.apply(fun, invocant, args); +} + +function wrapPrivileged(obj, win) { + // Primitives pass straight through. + if (!isWrappable(obj)) { + return obj; + } + + // No double wrapping. + if (isWrapper(obj)) { + throw new Error("Trying to double-wrap object!"); + } + + let { windowID, proxies, handler } = perWindowInfo.get(win) || {}; + // |windowUtils| is undefined if |win| is a non-window object + // such as a sandbox. + let currentID = win.windowGlobalChild + ? win.windowGlobalChild.innerWindowId + : 0; + // Values are dead objects if the inner window is changed. + if (windowID !== currentID) { + windowID = currentID; + proxies = new WeakMap(); + handler = Cu.cloneInto(SpecialPowersHandler, win, { + cloneFunctions: true, + }); + handler.wrapped = new win.WeakMap(); + perWindowInfo.set(win, { windowID, proxies, handler }); + } + + if (proxies.has(obj)) { + return proxies.get(obj).proxy; + } + + let className = Cu.getClassName(obj, true); + if (className === "ArrayBuffer") { + // Since |new Uint8Array(<proxy>)| doesn't work as expected, we have to + // return a real ArrayBuffer. + return obj instanceof win.ArrayBuffer ? obj : Cu.cloneInto(obj, win); + } + + let dummy; + if (typeof obj === "function") { + dummy = Cu.exportFunction(function () {}, win); + } else { + dummy = new win.Object(); + } + handler.wrapped.set(dummy, { obj }); + + let proxy = new win.Proxy(dummy, handler); + wrappedObjects.set(proxy, obj); + switch (className) { + case "AnonymousContent": + // Caching anonymous content will cause crashes (bug 1636015). + break; + case "CSS2Properties": + case "CSSStyleRule": + case "CSSStyleSheet": + // Caching these classes will cause memory leaks. + break; + default: + proxies.set(obj, { proxy }); + break; + } + return proxy; +} + +function unwrapPrivileged(x) { + // We don't wrap primitives, so sometimes we have a primitive where we'd + // expect to have a wrapper. The proxy pretends to be the type that it's + // emulating, so we can just as easily check isWrappable() on a proxy as + // we can on an unwrapped object. + if (!isWrappable(x)) { + return x; + } + + // If we have a wrappable type, make sure it's wrapped. + if (!isWrapper(x)) { + throw new Error("Trying to unwrap a non-wrapped object!"); + } + + // unwrapped. + return wrappedObjects.get(x); +} + +function wrapExceptions(global, fn) { + try { + return fn(); + } catch (e) { + throw wrapIfUnwrapped(e, global); + } +} + +let SpecialPowersHandler = { + construct(target, args) { + // The arguments may or may not be wrappers. Unwrap them if necessary. + var unwrappedArgs = Array.from(Cu.waiveXrays(args), x => + unwrapIfWrapped(Cu.unwaiveXrays(x)) + ); + + // We want to invoke "obj" as a constructor, but using unwrappedArgs as + // the arguments. + let global = Cu.getGlobalForObject(this); + return wrapExceptions(global, () => + wrapIfUnwrapped( + Reflect.construct(this.wrapped.get(target).obj, unwrappedArgs), + global + ) + ); + }, + + apply(target, thisValue, args) { + let wrappedObject = this.wrapped.get(target).obj; + let global = Cu.getGlobalForObject(this); + // The invocant and arguments may or may not be wrappers. Unwrap + // them if necessary. + var invocant = unwrapIfWrapped(thisValue); + + return wrapExceptions(global, () => { + if (noAutoWrap.has(wrappedObject)) { + args = Array.from(Cu.waiveXrays(args), x => Cu.unwaiveXrays(x)); + return doApply(wrappedObject, invocant, args); + } + + if (wrappedObject.name == "then") { + args = Array.from(Cu.waiveXrays(args), x => + wrapCallback(Cu.unwaiveXrays(x), global) + ); + } else { + args = Array.from(Cu.waiveXrays(args), x => + unwrapIfWrapped(Cu.unwaiveXrays(x)) + ); + } + + return wrapIfUnwrapped(doApply(wrappedObject, invocant, args), global); + }); + }, + + has(target, prop) { + return Reflect.has(this.wrapped.get(target).obj, prop); + }, + + get(target, prop, receiver) { + let global = Cu.getGlobalForObject(this); + return wrapExceptions(global, () => { + let obj = waiveXraysIfAppropriate(this.wrapped.get(target).obj, prop); + let val = Reflect.get(obj, prop); + return wrapIfUnwrapped(val, global); + }); + }, + + set(target, prop, val, receiver) { + return wrapExceptions(Cu.getGlobalForObject(this), () => { + let obj = waiveXraysIfAppropriate(this.wrapped.get(target).obj, prop); + return Reflect.set(obj, prop, unwrapIfWrapped(val)); + }); + }, + + delete(target, prop) { + return wrapExceptions(Cu.getGlobalForObject(this), () => { + return Reflect.deleteProperty(this.wrapped.get(target).obj, prop); + }); + }, + + defineProperty(target, prop, descriptor) { + throw new Error( + "Can't call defineProperty on SpecialPowers wrapped object" + ); + }, + + getOwnPropertyDescriptor(target, prop) { + let global = Cu.getGlobalForObject(this); + return wrapExceptions(global, () => { + let obj = waiveXraysIfAppropriate(this.wrapped.get(target).obj, prop); + let desc = Reflect.getOwnPropertyDescriptor(obj, prop); + + if (desc === undefined) { + return undefined; + } + + // Transitively maintain the wrapper membrane. + let wrapIfExists = key => { + if (key in desc) { + desc[key] = wrapIfUnwrapped(desc[key], global); + } + }; + + wrapIfExists("value"); + wrapIfExists("get"); + wrapIfExists("set"); + + // A trapping proxy's properties must always be configurable, but sometimes + // we come across non-configurable properties. Tell a white lie. + desc.configurable = true; + + return wrapIfUnwrapped(desc, global); + }); + }, + + ownKeys(target) { + let props = []; + + // Do the normal thing. + let wrappedObject = this.wrapped.get(target).obj; + let flt = a => !props.includes(a); + props = props.concat(Reflect.ownKeys(wrappedObject).filter(flt)); + + // If we've got an Xray wrapper, include the expandos as well. + if ("wrappedJSObject" in wrappedObject) { + props = props.concat( + Reflect.ownKeys(wrappedObject.wrappedJSObject).filter(flt) + ); + } + + return Cu.cloneInto(props, Cu.getGlobalForObject(this)); + }, + + preventExtensions(target) { + throw new Error( + "Can't call preventExtensions on SpecialPowers wrapped object" + ); + }, +}; + +function wrapCallback(cb, win) { + // Do not wrap if it is already privileged. + if (!isWrappable(cb) || Cu.getObjectPrincipal(cb).isSystemPrincipal) { + return cb; + } + return function SpecialPowersCallbackWrapper() { + var args = Array.from(arguments, obj => wrapIfUnwrapped(obj, win)); + let invocant = wrapIfUnwrapped(this, win); + return unwrapIfWrapped(cb.apply(invocant, args)); + }; +} + +function wrapCallbackObject(obj, win) { + // Do not wrap if it is already privileged. + if (!isWrappable(obj) || Cu.getObjectPrincipal(obj).isSystemPrincipal) { + return obj; + } + obj = Cu.waiveXrays(obj); + var wrapper = {}; + for (var i in obj) { + if (typeof obj[i] == "function") { + wrapper[i] = wrapCallback(Cu.unwaiveXrays(obj[i]), win); + } else { + wrapper[i] = obj[i]; + } + } + return wrapper; +} + +function disableAutoWrap(...objs) { + objs.forEach(x => noAutoWrap.add(x)); +} + +export var WrapPrivileged = { + wrap: wrapIfUnwrapped, + unwrap: unwrapIfWrapped, + + isWrapper, + + wrapCallback, + wrapCallbackObject, + + disableAutoWrap, +}; |