gecko/js/xpconnect/wrappers/AccessCheck.h

152 lines
5.6 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 "jsapi.h"
#include "jswrapper.h"
#include "WrapperFactory.h"
class nsIPrincipal;
namespace xpc {
class AccessCheck {
public:
static bool subsumes(JSCompartment *a, JSCompartment *b);
static bool isChrome(JSCompartment *compartment);
static bool callerIsChrome();
static nsIPrincipal *getPrincipal(JSCompartment *compartment);
static bool isCrossOriginAccessPermitted(JSContext *cx, JSObject *obj, jsid id,
js::Wrapper::Action act);
static bool isSystemOnlyAccessPermitted(JSContext *cx);
static bool isLocationObjectSameOrigin(JSContext *cx, JSObject *wrapper);
static bool needsSystemOnlyWrapper(JSObject *obj);
static bool isScriptAccessOnly(JSContext *cx, JSObject *wrapper);
static void deny(JSContext *cx, jsid id);
};
struct Policy {
typedef js::Wrapper::Permission Permission;
static const Permission PermitObjectAccess = js::Wrapper::PermitObjectAccess;
static const Permission PermitPropertyAccess = js::Wrapper::PermitPropertyAccess;
static const Permission DenyAccess = js::Wrapper::DenyAccess;
};
// This policy permits access to all properties.
struct Permissive : public Policy {
static bool check(JSContext *cx, JSObject *wrapper, jsid id, js::Wrapper::Action act,
Permission &perm) {
perm = PermitObjectAccess;
return true;
}
};
// This policy only permits access to the object if the subject can touch
// system objects.
struct OnlyIfSubjectIsSystem : public Policy {
static bool check(JSContext *cx, JSObject *wrapper, jsid id, js::Wrapper::Action act,
Permission &perm) {
if (AccessCheck::isSystemOnlyAccessPermitted(cx)) {
perm = PermitObjectAccess;
return true;
}
perm = DenyAccess;
JSAutoEnterCompartment ac;
if (!ac.enter(cx, wrapper))
return false;
AccessCheck::deny(cx, id);
return false;
}
};
// This policy only permits access to properties that are safe to be used
// across origins.
struct CrossOriginAccessiblePropertiesOnly : public Policy {
static bool check(JSContext *cx, JSObject *wrapper, jsid id, js::Wrapper::Action act,
Permission &perm) {
// Location objects should always use LocationPolicy.
MOZ_ASSERT(!WrapperFactory::IsLocationObject(js::UnwrapObject(wrapper)));
if (AccessCheck::isCrossOriginAccessPermitted(cx, wrapper, id, act)) {
perm = PermitPropertyAccess;
return true;
}
perm = DenyAccess;
JSAutoEnterCompartment ac;
if (!ac.enter(cx, wrapper))
return false;
AccessCheck::deny(cx, id);
return false;
}
};
// We need a special security policy for Location objects.
//
// Location objects are special because their effective principal is that of
// the outer window, not the inner window. So while the security characteristics
// of most objects can be inferred from their compartments, those of the Location
// object cannot. This has two implications:
//
// 1 - Same-compartment access of Location objects is not necessarily allowed.
// This means that objects must see a security wrapper around Location objects
// in their own compartment.
// 2 - Cross-origin access of Location objects is not necessarily forbidden.
// Since the security decision depends on the current state of the outer window,
// we can't make it at wrap time. Instead, we need to make it at the time of
// access.
//
// So for any Location object access, be it same-compartment or cross-compartment,
// we need to do a dynamic security check to determine whether the outer window is
// same-origin with the caller.
//
// So this policy first checks whether the access is something that any code,
// same-origin or not, is allowed to make. If it isn't, it _also_ checks the
// state of the outer window to determine whether we happen to be same-origin
// at the moment.
struct LocationPolicy : public Policy {
static bool check(JSContext *cx, JSObject *wrapper, jsid id, js::Wrapper::Action act,
Permission &perm) {
// We should only be dealing with Location objects here.
MOZ_ASSERT(WrapperFactory::IsLocationObject(js::UnwrapObject(wrapper)));
// Default to deny.
perm = DenyAccess;
// Location object security is complicated enough. Don't allow punctures.
if (act != js::Wrapper::PUNCTURE &&
(AccessCheck::isCrossOriginAccessPermitted(cx, wrapper, id, act) ||
AccessCheck::isLocationObjectSameOrigin(cx, wrapper))) {
perm = PermitPropertyAccess;
return true;
}
JSAutoEnterCompartment ac;
if (!ac.enter(cx, wrapper))
return false;
AccessCheck::deny(cx, id);
return false;
}
};
// This policy only permits access to properties if they appear in the
// objects exposed properties list.
struct ExposedPropertiesOnly : public Policy {
static bool check(JSContext *cx, JSObject *wrapper, jsid id, js::Wrapper::Action act,
Permission &perm);
};
// Components specific policy
struct ComponentsObjectPolicy : public Policy {
static bool check(JSContext *cx, JSObject *wrapper, jsid id, js::Wrapper::Action act,
Permission &perm);
};
}