[Scummvm-devel] Detecting patched games / SCI bug reports

[M. Kiewitz]

> Hi Martin,
> 
> I have the feeling that you took what I wrote in my
> previous emails as some kind of offense, an attack against
> the work you and t

Hi Max,

No, you misunderstood me in that case. I was just saying why there are plenty of bugs left.

> > For SCI, the current commented out versions are "full"
> pirate versions, which means the crack is even embedded in
> the resource files. There is no way that a user could patch
> his legitimate copy that way.
> [... I am not actually disagreeing with most you say, but
> note that Oystein and me are users, too, and I definitely
> think we could make such a patch. However, this is beyond
> the point of the actual debate ... ]

The resource files are fully modified. Anyone with a legitimate version of the game would add a patch file for the copy protection room instead. Sure, a legitimate user could create such patch files, but modifying the resource files directly instead is much more difficult and complicated. And also the game won't get detected afterwards anymore anyway.

> > In this case blacklisting won't matter at all, because
> even if we didnt blacklist it, it wouldnt work anyway. Same
> goes for the pirated version of sq4. For those games pirates
> easily "fixing" ScummVM to make it work isn't possible. I
> guess if a pirate was competent enough, he would even add
> the copyprotection patches into our patching code and patch
> those games on-the-fly instead of removing the detection for
> patched games.
> 
> Nah, we wouldn't want to do anything to actively support
> cracked games.

I said pirates would do that. The SCI script patching system was introduced to fix script bugs on-the-fly. But it could get used to patch out copy protections as well. Of course *I* wouldn't do that, but pirates could.

> What we *are* discussing is whether we should have a
> blacklist of known pirated MD5s. You want this because it
> would reduce your workload quite a bit, filtering out bad
> reports much earlier. Much understandable, I think

Like i said - those pirated md5 entries in the SCI engine are *definitely* pirated versions. There is no way a legitimate user would have modified his game that way, because that would mean actually deleting the game and downloading it from the internet (which is pirating anyway).

Detecting copy protection patches is a different matter. It's possible to do that, too (by looking for patch files that go against copy protection rooms). At least we should add some information dialog explaining that the version used is cracked and that we won't support it. This would match pirated lsl5, because that game does have separate copy protection patch files (that also crash ScummVM).

> Others here have voiced concern about this, fearing that
> this might interfere with people's right to modify their own
> game data. This is also understandable to a degree, though
> indeed, I don't see bypassing copy protection as the primary
> motivation there, but rather things like fan translation,
> and other fan add-ons, which *do* exist and are even still
> being newly created. But as you said yourself, those would
> not be on the blacklist anyway, so this point is moot.
> Still, there *is* some concern there by people, whether we
> agree with it or not.

Patching copy protection rooms in sci games is definitely cracking. I wouldn't check for anything else, so fan translations and such things are  still possible.

> But on the other hand, I am concerned that it would be
> trivial to turn such a blacklist into a whitelist. Trivial
> as in: change a few lines (probably exactly one), and you
> get all cracked versions fully "supported" (including their
> bugs and crashes, of course), which, in the end, would be
> another case of a protection system (think DRM) that hurts a
> few regular users, but not the real pirates... 

In the cases of LSL5 and SQ4 the crack patches do not work currently at all because of bugs in those scripts. Fixing it is definitely not a 2-line change. Still if a pirate is capable of "fixing" it, why not? It just won't get supported inside ScummVM, so pirates would still need to go over that middle-man and get every update from him instead. Also no bug reports nor daily builds for them.

> All the more reason to ask for help, so that people re-test
> those bugs, ask the submitter to test whether the bug occurs
> with the original engine, etc. etc. Some bugs have no
> comment at all, not even one of these. My email was meant to
> stimulate other devs here to step in and help out if they
> have some time. :).

I looked through some and most of those w/o any comment were fan-game bugs. And to be honest i won't look into those at all for now.

> > Also please keep in mind that almost the whole SCI
> team is currently away. Some of the left-over bugs are meant
> to get looked on by walter and or md5.
> Ah, I didn't know that, so I hardly could have kept it in
> mind, but now I will :). Actually, the way you phrase it, it
> sounds as if I should have known -- did I miss an email on
> -devel ?

I think it was pretty obvious, the last 35 fixed sci bugs were fixed by me. Anyway I just wanted to make you aware that no one else is currently working on it, nothing else.

Regards