DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Implementation

Mercurial (5b81998bb7ab)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: set ts=8 sts=4 et sw=4 tw=99:
 * 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 jswrapper_h
#define jswrapper_h

#include "mozilla/Attributes.h"

#include "jsapi.h"
#include "jsproxy.h"

namespace js {

class DummyFrameGuard;

/*
 * A wrapper is a proxy with a target object to which it generally forwards
 * operations, but may restrict access to certain operations or instrument
 * the trap operations in various ways. A wrapper is distinct from a Direct Proxy
 * Handler in the sense that it can be "unwrapped" in C++, exposing the underlying
 * object (Direct Proxy Handlers have an underlying target object, but don't
 * expect to expose this object via any kind of unwrapping operation). Callers
 * should be careful to avoid unwrapping security wrappers in the wrong context.
 */
class JS_FRIEND_API(Wrapper) : public DirectProxyHandler
{
    unsigned mFlags;
    bool mSafeToUnwrap;

  public:
    using BaseProxyHandler::Action;

    enum Flags {
        CROSS_COMPARTMENT = 1 << 0,
        LAST_USED_FLAG = CROSS_COMPARTMENT
    };

    /*
     * Wrappers can explicitly specify that they are unsafe to unwrap from a
     * security perspective (as is the case for SecurityWrappers). If a wrapper
     * is not safe to unwrap, operations requiring full access to the underlying
     * object (via CheckedUnwrap) will throw. Otherwise, they will succeed.
     */
    void setSafeToUnwrap(bool safe) { mSafeToUnwrap = safe; }
    bool isSafeToUnwrap() { return mSafeToUnwrap; }

    static JSObject *New(JSContext *cx, JSObject *obj, JSObject *proto,
                         JSObject *parent, Wrapper *handler);

    static JSObject *Renew(JSContext *cx, JSObject *existing, JSObject *obj, Wrapper *handler);

    static Wrapper *wrapperHandler(JSObject *wrapper);

    static JSObject *wrappedObject(JSObject *wrapper);

    unsigned flags() const {
        return mFlags;
    }

    explicit Wrapper(unsigned flags, bool hasPrototype = false);

    virtual ~Wrapper();

    static Wrapper singleton;
    static Wrapper singletonWithPrototype;

    static void *getWrapperFamily();
};

/* Base class for all cross compartment wrapper handlers. */
class JS_FRIEND_API(CrossCompartmentWrapper) : public Wrapper
{
  public:
    CrossCompartmentWrapper(unsigned flags, bool hasPrototype = false);

    virtual ~CrossCompartmentWrapper();

    virtual bool finalizeInBackground(Value priv) MOZ_OVERRIDE;

    /* ES5 Harmony fundamental wrapper traps. */
    virtual bool preventExtensions(JSContext *cx, HandleObject wrapper) MOZ_OVERRIDE;
    virtual bool getPropertyDescriptor(JSContext *cx, HandleObject wrapper, HandleId id,
                                       PropertyDescriptor *desc, unsigned flags) MOZ_OVERRIDE;
    virtual bool getOwnPropertyDescriptor(JSContext *cx, HandleObject wrapper, HandleId id,
                                          PropertyDescriptor *desc, unsigned flags) MOZ_OVERRIDE;
    virtual bool defineProperty(JSContext *cx, HandleObject wrapper, HandleId id,
                                PropertyDescriptor *desc) MOZ_OVERRIDE;
    virtual bool getOwnPropertyNames(JSContext *cx, HandleObject wrapper,
                                     AutoIdVector &props) MOZ_OVERRIDE;
    virtual bool delete_(JSContext *cx, HandleObject wrapper, HandleId id, bool *bp) MOZ_OVERRIDE;
    virtual bool enumerate(JSContext *cx, HandleObject wrapper, AutoIdVector &props) MOZ_OVERRIDE;

    /* ES5 Harmony derived wrapper traps. */
    virtual bool has(JSContext *cx, HandleObject wrapper, HandleId id, bool *bp) MOZ_OVERRIDE;
    virtual bool hasOwn(JSContext *cx, HandleObject wrapper, HandleId id, bool *bp) MOZ_OVERRIDE;
    virtual bool get(JSContext *cx, HandleObject wrapper, HandleObject receiver,
                     HandleId id, MutableHandleValue vp) MOZ_OVERRIDE;
    virtual bool set(JSContext *cx, HandleObject wrapper, HandleObject receiver,
                     HandleId id, bool strict, MutableHandleValue vp) MOZ_OVERRIDE;
    virtual bool keys(JSContext *cx, HandleObject wrapper, AutoIdVector &props) MOZ_OVERRIDE;
    virtual bool iterate(JSContext *cx, HandleObject wrapper, unsigned flags,
                         MutableHandleValue vp) MOZ_OVERRIDE;

    /* Spidermonkey extensions. */
    virtual bool isExtensible(JSObject *proxy) MOZ_OVERRIDE;
    virtual bool call(JSContext *cx, HandleObject wrapper, const CallArgs &args) MOZ_OVERRIDE;
    virtual bool construct(JSContext *cx, HandleObject wrapper, const CallArgs &args) MOZ_OVERRIDE;
    virtual bool nativeCall(JSContext *cx, IsAcceptableThis test, NativeImpl impl,
                            CallArgs args) MOZ_OVERRIDE;
    virtual bool hasInstance(JSContext *cx, HandleObject wrapper, MutableHandleValue v,
                             bool *bp) MOZ_OVERRIDE;
    virtual const char *className(JSContext *cx, HandleObject proxy) MOZ_OVERRIDE;
    virtual JSString *fun_toString(JSContext *cx, HandleObject wrapper,
                                   unsigned indent) MOZ_OVERRIDE;
    virtual bool regexp_toShared(JSContext *cx, HandleObject proxy, RegExpGuard *g) MOZ_OVERRIDE;
    virtual bool defaultValue(JSContext *cx, HandleObject wrapper, JSType hint,
                              MutableHandleValue vp) MOZ_OVERRIDE;
    virtual bool getPrototypeOf(JSContext *cx, HandleObject proxy, MutableHandleObject protop);

    static CrossCompartmentWrapper singleton;
    static CrossCompartmentWrapper singletonWithPrototype;
};

/*
 * Base class for security wrappers. A security wrapper is potentially hiding
 * all or part of some wrapped object thus SecurityWrapper defaults to denying
 * access to the wrappee. This is the opposite of Wrapper which tries to be
 * completely transparent.
 *
 * NB: Currently, only a few ProxyHandler operations are overridden to deny
 * access, relying on derived SecurityWrapper to block access when necessary.
 */
template <class Base>
class JS_FRIEND_API(SecurityWrapper) : public Base
{
  public:
    SecurityWrapper(unsigned flags);

    virtual bool isExtensible(JSObject *wrapper) MOZ_OVERRIDE;
    virtual bool preventExtensions(JSContext *cx, HandleObject wrapper) MOZ_OVERRIDE;
    virtual bool enter(JSContext *cx, HandleObject wrapper, HandleId id, Wrapper::Action act,
                       bool *bp) MOZ_OVERRIDE;
    virtual bool nativeCall(JSContext *cx, IsAcceptableThis test, NativeImpl impl,
                            CallArgs args) MOZ_OVERRIDE;
    virtual bool defaultValue(JSContext *cx, HandleObject wrapper, JSType hint,
                              MutableHandleValue vp) MOZ_OVERRIDE;
    virtual bool objectClassIs(HandleObject obj, ESClassValue classValue,
                               JSContext *cx) MOZ_OVERRIDE;
    virtual bool regexp_toShared(JSContext *cx, HandleObject proxy, RegExpGuard *g) MOZ_OVERRIDE;
    virtual bool defineProperty(JSContext *cx, HandleObject wrapper, HandleId id,
                                PropertyDescriptor *desc) MOZ_OVERRIDE;

    /*
     * Allow our subclasses to select the superclass behavior they want without
     * needing to specify an exact superclass.
     */
    typedef Base Permissive;
    typedef SecurityWrapper<Base> Restrictive;
};

typedef SecurityWrapper<Wrapper> SameCompartmentSecurityWrapper;
typedef SecurityWrapper<CrossCompartmentWrapper> CrossCompartmentSecurityWrapper;

class JS_FRIEND_API(DeadObjectProxy) : public BaseProxyHandler
{
  public:
    static int sDeadObjectFamily;

    explicit DeadObjectProxy();

    /* ES5 Harmony fundamental wrapper traps. */
    virtual bool preventExtensions(JSContext *cx, HandleObject proxy) MOZ_OVERRIDE;
    virtual bool getPropertyDescriptor(JSContext *cx, HandleObject wrapper, HandleId id,
                                       PropertyDescriptor *desc, unsigned flags) MOZ_OVERRIDE;
    virtual bool getOwnPropertyDescriptor(JSContext *cx, HandleObject wrapper, HandleId id,
                                          PropertyDescriptor *desc, unsigned flags) MOZ_OVERRIDE;
    virtual bool defineProperty(JSContext *cx, HandleObject wrapper, HandleId id,
                                PropertyDescriptor *desc) MOZ_OVERRIDE;
    virtual bool getOwnPropertyNames(JSContext *cx, HandleObject wrapper,
                                     AutoIdVector &props) MOZ_OVERRIDE;
    virtual bool delete_(JSContext *cx, HandleObject wrapper, HandleId id, bool *bp) MOZ_OVERRIDE;
    virtual bool enumerate(JSContext *cx, HandleObject wrapper, AutoIdVector &props) MOZ_OVERRIDE;

    /* Spidermonkey extensions. */
    virtual bool isExtensible(JSObject *proxy) MOZ_OVERRIDE;
    virtual bool call(JSContext *cx, HandleObject proxy, const CallArgs &args) MOZ_OVERRIDE;
    virtual bool construct(JSContext *cx, HandleObject proxy, const CallArgs &args) MOZ_OVERRIDE;
    virtual bool nativeCall(JSContext *cx, IsAcceptableThis test, NativeImpl impl,
                            CallArgs args) MOZ_OVERRIDE;
    virtual bool hasInstance(JSContext *cx, HandleObject proxy, MutableHandleValue v,
                             bool *bp) MOZ_OVERRIDE;
    virtual bool objectClassIs(HandleObject obj, ESClassValue classValue,
                               JSContext *cx) MOZ_OVERRIDE;
    virtual const char *className(JSContext *cx, HandleObject proxy) MOZ_OVERRIDE;
    virtual JSString *fun_toString(JSContext *cx, HandleObject proxy, unsigned indent) MOZ_OVERRIDE;
    virtual bool regexp_toShared(JSContext *cx, HandleObject proxy, RegExpGuard *g) MOZ_OVERRIDE;
    virtual bool defaultValue(JSContext *cx, HandleObject obj, JSType hint,
                              MutableHandleValue vp) MOZ_OVERRIDE;
    virtual bool getElementIfPresent(JSContext *cx, HandleObject obj, HandleObject receiver,
                                     uint32_t index, MutableHandleValue vp,
                                     bool *present) MOZ_OVERRIDE;
    virtual bool getPrototypeOf(JSContext *cx, HandleObject proxy,
                                MutableHandleObject protop) MOZ_OVERRIDE;

    static DeadObjectProxy singleton;
};

extern JSObject *
TransparentObjectWrapper(JSContext *cx, HandleObject existing, HandleObject obj,
                         HandleObject wrappedProto, HandleObject parent,
                         unsigned flags);

// Proxy family for wrappers. Public so that IsWrapper() can be fully inlined by
// jsfriendapi users.
extern JS_FRIEND_DATA(int) sWrapperFamily;

inline bool
IsWrapper(JSObject *obj)
{
    return IsProxy(obj) && GetProxyHandler(obj)->family() == &sWrapperFamily;
}

// Given a JSObject, returns that object stripped of wrappers. If
// stopAtOuter is true, then this returns the outer window if it was
// previously wrapped. Otherwise, this returns the first object for
// which JSObject::isWrapper returns false.
JS_FRIEND_API(JSObject *)
UncheckedUnwrap(JSObject *obj, bool stopAtOuter = true, unsigned *flagsp = NULL);

// Given a JSObject, returns that object stripped of wrappers. At each stage,
// the security wrapper has the opportunity to veto the unwrap. Since checked
// code should never be unwrapping outer window wrappers, we always stop at
// outer windows.
JS_FRIEND_API(JSObject *)
CheckedUnwrap(JSObject *obj, bool stopAtOuter = true);

// Unwrap only the outermost security wrapper, with the same semantics as
// above. This is the checked version of Wrapper::wrappedObject.
JS_FRIEND_API(JSObject *)
UnwrapOneChecked(JSObject *obj, bool stopAtOuter = true);

JS_FRIEND_API(bool)
IsCrossCompartmentWrapper(JSObject *obj);

bool
IsDeadProxyObject(JSObject *obj);

JSObject *
NewDeadProxyObject(JSContext *cx, JSObject *parent);

void
NukeCrossCompartmentWrapper(JSContext *cx, JSObject *wrapper);

bool
RemapWrapper(JSContext *cx, JSObject *wobj, JSObject *newTarget);

JS_FRIEND_API(bool)
RemapAllWrappersForObject(JSContext *cx, JSObject *oldTarget,
                          JSObject *newTarget);

// API to recompute all cross-compartment wrappers whose source and target
// match the given filters.
JS_FRIEND_API(bool)
RecomputeWrappers(JSContext *cx, const CompartmentFilter &sourceFilter,
                  const CompartmentFilter &targetFilter);

/*
 * This auto class should be used around any code, such as brain transplants,
 * that may touch dead zones. Brain transplants can cause problems
 * because they operate on all compartments, whether live or dead. A brain
 * transplant can cause a formerly dead object to be "reanimated" by causing a
 * read or write barrier to be invoked on it during the transplant. In this way,
 * a zone becomes a zombie, kept alive by repeatedly consuming
 * (transplanted) brains.
 *
 * To work around this issue, we observe when mark bits are set on objects in
 * dead zones. If this happens during a brain transplant, we do a full,
 * non-incremental GC at the end of the brain transplant. This will clean up any
 * objects that were improperly marked.
 */
struct JS_FRIEND_API(AutoMaybeTouchDeadZones)
{
    // The version that takes an object just uses it for its runtime.
    AutoMaybeTouchDeadZones(JSContext *cx);
    AutoMaybeTouchDeadZones(JSObject *obj);
    ~AutoMaybeTouchDeadZones();

  private:
    JSRuntime *runtime;
    unsigned markCount;
    bool inIncremental;
    bool manipulatingDeadZones;
};

} /* namespace js */

#endif /* jswrapper_h */