copy protection - was: Re: Is it time for playing games on WINE?
jonwil at tpgi.com.au
Wed Nov 5 00:00:23 CST 2003
> None whatsoever, the driver "reimplementation" is clearly a DMCA
> violation. The proper way to do that is to somehow load the driver and
> let it perform all the checks it wants to perform; a dummy driver that
> returns magic values to bypass the checks is not acceptable.
From what I know about copy protection, they basicly work as follows:
1.There is special code that is designed to detect the presense of a
debugger such as SoftIce
2.There is special code to read special "hidden" information from the CD
(and if it doesnt exist or isnt correct, reject the CD as copied)
and 3.There are modifications to the exe file/game code (e.g. encrypted
code or messed up Import Address Tables or whatever else), sometimes
relying on the hidden CD data, sometimes not.
From looking at the posted "safedisk-dmca.diff" and from looking at
secrdv.sys in IDA pro it would appear that the primary purpose of
secdrv.sys is to allow access to areas in kernel mode not normally
accessable to userland code, more specificly, its used to check certain
things for the presense of a kernel level debugger (e.g. SoftIce).
The actual copy protection code is (as far as I know, correct me if I am
wrong) contained in various dlls and other code (including code thats
inside the game exe itself) that operates in userland and sends IOCTLs to
the CDROM drive to get the secret data back.
Basicly as long as our code:
A.cant run "copied" safedisk disks ("perfect copies" and "no-cd cracks" aside)
and B.cant be modified to run "copied" safedisk disks (e.g. by disabling
some parts of the WINE code that performed checks)
then I think that we would probobly not be violating the DMCA (although IANAL)
If someone wants to disagree with me or has evidence refuting my statements
(legally or technically, please do post here or mail me.
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