Details
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Bug
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Resolution: Unresolved
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P2: Important
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None
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5.15.2
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None
Description
When passing a complex type inside a variant map, I can't safely validate and cast the value.
Imagine getting pixmap data sent as a struct, like (iiiay) (width, height, rowstride, byte array) inside of a variant map a(sv), like is done in freedesktop Notification spec. I can't check whether the type I get matches the expected signature and doing a qdbus_cast might trigger an assert in libdbus should the client sends bogus data.
DBus setup:
struct MyImage {
int width, height, rowStride;
QByteArray data;
};
QDBusArgument &operator<< (QDBusArgument &argument, const MyImage &image) {
argument.beginStructure();
argument << image.width;
argument << image.height;
argument << image.rowStride;
argument << image.data;
argument.endStructure();
return argument;
}
inline const QDBusArgument &operator>>(const QDBusArgument &argument, MyImage &image) {
argument.beginStructure();
argument >> image.width;
argument >> image.height;
argument >> image.rowStride;
argument >> image.data;
argument.endStructure();
return argument;
}
Q_DECLARE_METATYPE(MyImage)
qDBusRegisterMetaType<MyImage>();
I can read the image like so
QDBusPendingReply<QVariantMap> reply = ...;
...
QVariantMap map = reply.value():
auto dataArgument = map.value("data").value<QDBusArgument>();
auto image = qdbus_cast<MyImage>(dataArgument);
The qdbus_cast call will trigger an assert in libdbus if the structure sent by the client does not match the expected signature.
I can only check currentType() being QDBusArgument::StructureType but I can't guarantee the fields inside the structure are the ones I expect.