gecko/js/xpconnect/wrappers/AccessCheck.cpp
Bobby Holley e9c4522522 Bug 975042 - Remove the special COW support for Date. r=peterv
As soon as Date is on Xrays, this stuff won't work anyway. Henceforth, content
access to chrome Date objects is forbidden, and APIs should use something like
|new contentWindow.Date()| for any Date object they wish to expose to content.
2014-03-23 11:02:12 -03:00

362 lines
10 KiB
C++

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set ts=4 sw=4 et tw=99 ft=cpp:
*
* 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/. */
#include "AccessCheck.h"
#include "nsJSPrincipals.h"
#include "nsGlobalWindow.h"
#include "XPCWrapper.h"
#include "XrayWrapper.h"
#include "jsfriendapi.h"
#include "mozilla/dom/BindingUtils.h"
#include "mozilla/dom/WindowBinding.h"
#include "nsIDOMWindowCollection.h"
#include "nsJSUtils.h"
using namespace mozilla;
using namespace JS;
using namespace js;
namespace xpc {
nsIPrincipal *
GetCompartmentPrincipal(JSCompartment *compartment)
{
return nsJSPrincipals::get(JS_GetCompartmentPrincipals(compartment));
}
nsIPrincipal *
GetObjectPrincipal(JSObject *obj)
{
return GetCompartmentPrincipal(js::GetObjectCompartment(obj));
}
// Does the principal of compartment a subsume the principal of compartment b?
bool
AccessCheck::subsumes(JSCompartment *a, JSCompartment *b)
{
nsIPrincipal *aprin = GetCompartmentPrincipal(a);
nsIPrincipal *bprin = GetCompartmentPrincipal(b);
return aprin->Subsumes(bprin);
}
bool
AccessCheck::subsumes(JSObject *a, JSObject *b)
{
return subsumes(js::GetObjectCompartment(a), js::GetObjectCompartment(b));
}
// Same as above, but considering document.domain.
bool
AccessCheck::subsumesConsideringDomain(JSCompartment *a, JSCompartment *b)
{
nsIPrincipal *aprin = GetCompartmentPrincipal(a);
nsIPrincipal *bprin = GetCompartmentPrincipal(b);
return aprin->SubsumesConsideringDomain(bprin);
}
// Does the compartment of the wrapper subsumes the compartment of the wrappee?
bool
AccessCheck::wrapperSubsumes(JSObject *wrapper)
{
MOZ_ASSERT(js::IsWrapper(wrapper));
JSObject *wrapped = js::UncheckedUnwrap(wrapper);
return AccessCheck::subsumes(js::GetObjectCompartment(wrapper),
js::GetObjectCompartment(wrapped));
}
bool
AccessCheck::isChrome(JSCompartment *compartment)
{
nsIScriptSecurityManager *ssm = XPCWrapper::GetSecurityManager();
if (!ssm) {
return false;
}
bool privileged;
nsIPrincipal *principal = GetCompartmentPrincipal(compartment);
return NS_SUCCEEDED(ssm->IsSystemPrincipal(principal, &privileged)) && privileged;
}
bool
AccessCheck::isChrome(JSObject *obj)
{
return isChrome(js::GetObjectCompartment(obj));
}
bool
AccessCheck::callerIsChrome()
{
nsIScriptSecurityManager *ssm = XPCWrapper::GetSecurityManager();
if (!ssm)
return false;
bool subjectIsSystem;
nsresult rv = ssm->SubjectPrincipalIsSystem(&subjectIsSystem);
return NS_SUCCEEDED(rv) && subjectIsSystem;
}
nsIPrincipal *
AccessCheck::getPrincipal(JSCompartment *compartment)
{
return GetCompartmentPrincipal(compartment);
}
#define NAME(ch, str, cases) \
case ch: if (!strcmp(name, str)) switch (propChars[0]) { cases }; break;
#define PROP(ch, actions) case ch: { actions }; break;
#define RW(str) if (JS_FlatStringEqualsAscii(prop, str)) return true;
#define R(str) if (!set && JS_FlatStringEqualsAscii(prop, str)) return true;
#define W(str) if (set && JS_FlatStringEqualsAscii(prop, str)) return true;
// Hardcoded policy for cross origin property access. This was culled from the
// preferences file (all.js). We don't want users to overwrite highly sensitive
// security policies.
static bool
IsPermitted(const char *name, JSFlatString *prop, bool set)
{
size_t propLength;
const jschar *propChars =
JS_GetInternedStringCharsAndLength(JS_FORGET_STRING_FLATNESS(prop), &propLength);
if (!propLength)
return false;
switch (name[0]) {
NAME('L', "Location",
PROP('h', W("href"))
PROP('r', R("replace")))
case 'W':
if (!strcmp(name, "Window"))
return dom::WindowBinding::IsPermitted(prop, propChars[0], set);
break;
}
return false;
}
#undef NAME
#undef RW
#undef R
#undef W
static bool
IsFrameId(JSContext *cx, JSObject *objArg, jsid idArg)
{
RootedObject obj(cx, objArg);
RootedId id(cx, idArg);
obj = JS_ObjectToInnerObject(cx, obj);
MOZ_ASSERT(!js::IsWrapper(obj));
nsGlobalWindow* win = WindowOrNull(obj);
if (!win) {
return false;
}
nsCOMPtr<nsIDOMWindowCollection> col;
win->GetFrames(getter_AddRefs(col));
if (!col) {
return false;
}
nsCOMPtr<nsIDOMWindow> domwin;
if (JSID_IS_INT(id)) {
col->Item(JSID_TO_INT(id), getter_AddRefs(domwin));
} else if (JSID_IS_STRING(id)) {
col->NamedItem(nsDependentJSString(id), getter_AddRefs(domwin));
}
return domwin != nullptr;
}
static bool
IsWindow(const char *name)
{
return name[0] == 'W' && !strcmp(name, "Window");
}
bool
AccessCheck::isCrossOriginAccessPermitted(JSContext *cx, JSObject *wrapperArg, jsid idArg,
Wrapper::Action act)
{
if (!XPCWrapper::GetSecurityManager())
return true;
if (act == Wrapper::CALL)
return false;
RootedId id(cx, idArg);
RootedObject wrapper(cx, wrapperArg);
RootedObject obj(cx, Wrapper::wrappedObject(wrapper));
// For XOWs, we generally want to deny enumerate-like operations, but fail
// silently (see CrossOriginAccessiblePropertiesOnly::deny).
if (act == Wrapper::ENUMERATE)
return false;
const char *name;
const js::Class *clasp = js::GetObjectClass(obj);
MOZ_ASSERT(!XrayUtils::IsXPCWNHolderClass(Jsvalify(clasp)), "shouldn't have a holder here");
if (clasp->ext.innerObject)
name = "Window";
else
name = clasp->name;
if (JSID_IS_STRING(id)) {
if (IsPermitted(name, JSID_TO_FLAT_STRING(id), act == Wrapper::SET))
return true;
}
if (act != Wrapper::GET)
return false;
// Check for frame IDs. If we're resolving named frames, make sure to only
// resolve ones that don't shadow native properties. See bug 860494.
if (IsWindow(name)) {
if (JSID_IS_STRING(id) && !XrayUtils::IsXrayResolving(cx, wrapper, id)) {
bool wouldShadow = false;
if (!XrayUtils::HasNativeProperty(cx, wrapper, id, &wouldShadow) ||
wouldShadow)
{
return false;
}
}
return IsFrameId(cx, obj, id);
}
return false;
}
enum Access { READ = (1<<0), WRITE = (1<<1), NO_ACCESS = 0 };
static void
EnterAndThrow(JSContext *cx, JSObject *wrapper, const char *msg)
{
JSAutoCompartment ac(cx, wrapper);
JS_ReportError(cx, msg);
}
bool
ExposedPropertiesOnly::check(JSContext *cx, JSObject *wrapperArg, jsid idArg, Wrapper::Action act)
{
RootedObject wrapper(cx, wrapperArg);
RootedId id(cx, idArg);
RootedObject wrappedObject(cx, Wrapper::wrappedObject(wrapper));
if (act == Wrapper::CALL)
return true;
RootedId exposedPropsId(cx, GetRTIdByIndex(cx, XPCJSRuntime::IDX_EXPOSEDPROPS));
// We need to enter the wrappee's compartment to look at __exposedProps__,
// but we want to be in the wrapper's compartment if we call Deny().
//
// Unfortunately, |cx| can be in either compartment when we call ::check. :-(
JSAutoCompartment ac(cx, wrappedObject);
bool found = false;
if (!JS_HasPropertyById(cx, wrappedObject, exposedPropsId, &found))
return false;
// Always permit access to "length" and indexed properties of arrays.
if ((JS_IsArrayObject(cx, wrappedObject) ||
JS_IsTypedArrayObject(wrappedObject)) &&
((JSID_IS_INT(id) && JSID_TO_INT(id) >= 0) ||
(JSID_IS_STRING(id) && JS_FlatStringEqualsAscii(JSID_TO_FLAT_STRING(id), "length")))) {
return true; // Allow
}
// If no __exposedProps__ existed, deny access.
if (!found) {
return false;
}
if (id == JSID_VOID)
return true;
RootedValue exposedProps(cx);
if (!JS_LookupPropertyById(cx, wrappedObject, exposedPropsId, &exposedProps))
return false;
if (exposedProps.isNullOrUndefined())
return false;
if (!exposedProps.isObject()) {
EnterAndThrow(cx, wrapper, "__exposedProps__ must be undefined, null, or an Object");
return false;
}
RootedObject hallpass(cx, &exposedProps.toObject());
if (!AccessCheck::subsumes(js::UncheckedUnwrap(hallpass), wrappedObject)) {
EnterAndThrow(cx, wrapper, "Invalid __exposedProps__");
return false;
}
Access access = NO_ACCESS;
Rooted<JSPropertyDescriptor> desc(cx);
if (!JS_GetPropertyDescriptorById(cx, hallpass, id, 0, &desc)) {
return false; // Error
}
if (!desc.object() || !desc.isEnumerable())
return false;
if (!desc.value().isString()) {
EnterAndThrow(cx, wrapper, "property must be a string");
return false;
}
JSString *str = desc.value().toString();
size_t length;
const jschar *chars = JS_GetStringCharsAndLength(cx, str, &length);
if (!chars)
return false;
for (size_t i = 0; i < length; ++i) {
switch (chars[i]) {
case 'r':
if (access & READ) {
EnterAndThrow(cx, wrapper, "duplicate 'readable' property flag");
return false;
}
access = Access(access | READ);
break;
case 'w':
if (access & WRITE) {
EnterAndThrow(cx, wrapper, "duplicate 'writable' property flag");
return false;
}
access = Access(access | WRITE);
break;
default:
EnterAndThrow(cx, wrapper, "properties can only be readable or read and writable");
return false;
}
}
if (access == NO_ACCESS) {
EnterAndThrow(cx, wrapper, "specified properties must have a permission bit set");
return false;
}
if ((act == Wrapper::SET && !(access & WRITE)) ||
(act != Wrapper::SET && !(access & READ))) {
return false;
}
return true;
}
bool
ExposedPropertiesOnly::allowNativeCall(JSContext *cx, JS::IsAcceptableThis test,
JS::NativeImpl impl)
{
return js::IsTypedArrayThisCheck(test);
}
}