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New Method To Detect and Prove GPL Violations
qwerty writes "A paper to be presented at the upcoming academic conference Automated Software Engineering describes a new method to detect code theft and could be used to detect GPL violations in particular. While the co-called birthmarking method is demonstrated for Java, it is general enough to work for other languages as well. The API Benchmark observes the interaction between an application and (dynamic) libraries that are part of the runtime system. This captures the observable behavior of the program and cannot be easily foiled using code obfuscation techniques, as shown in the paper (PDF). Once such a birthmark is captured, it can be searched for in other programs. By capturing the birthmarks from popular open-source frameworks, GPL-violating applications could be identified."
I used to be a research assistent, and at university, we used this technique to see if students copied their assignments. They could rename variables, move pieces of text, change comments all the way they liked, but the execution profile stayed the same. We caught a lot of students, and they never figured out how we did it.
What is the false positive rate for this method? What if two programs just happen to do the same thing and the authors happened to choose similar ways to do it. Would this method conclude that one originated with the other? It's not a copyright violation because neither is a derivative work of the other.
Also, it occurs to me that this method would probably not be as useful as expected for detecting GPL violations. It would think it would only be effective for checking where you have source code available, or at the very least enough symbol table information to make comparisons, which you are not likely to have if somebody is violating the GPL because that implies no source code anyways (and almost certainly no symbol table information for the binary).
File under 'M' for 'Manic ranting'
An identical library call signature for a nontrivial part of the execution could be produced by a clean-room analysis or even independent development of an equivalent component. Neither of these is a GPL violation.
This is not to say that the technique wouldn't be useful for hunting down GPL violations. But a positive is not difinitive by itself.
Meanwhile code obfuscation (even automatically generated obfuscation) could easily modify at least the timing, if not the order, of such calls.
Nevertheless this is a powerful tool: An hunk of GPL code that hasn't had its flow obfuscated systematically (even code that HAS been obfuscated but not systematically) will have large swaths of code that trips the detector. And it doesn't require reverse engineering until after the alarm goes off.
Good job, guys.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
GGA! The GNU Genuine Advantage program!
Karma cannot be described by words alone.
Pitchfork? ... Check ... Check ... Check ... Check ... Check
Torch?
Map of Corporate Castle locations?
FSF Lawyers programmed to be speed dialed in emergencies?
Desire to burn the non-believers?
Okay, I'm ready! What IRC Channel are we meeting in?
load "$",8,1
As you can imagine I really don't like the GPL or the FSF or Richard Stallman or any of his friends too much. While I recognize their contributions I think that they've fallen into the trap of trying to force everyone to convert to what has become a quasi-religion where the Inquisition is more important than celebrating mass.
I looked through the paper, and it is cool stuff. But I couldn't see where it supposed the system would work well for other languages, and I wonder if it really would be so good.
Java has a very large standard library that is always dynamically linked, and hence can easily be instrumented as the technique requires. C allows static linking which would make such hooking much more difficult. Additionally Java executes in a very standard environment due to the Virtual Machine, where as other languages may have varying ABIs type sizes and other properties that could add significant noise to the birthmark.
That said, system calls are always hookable and reasonably standard, so maybe this technique could be applied successfully there for malware detection or similar?
-- Mike
keyboard lubricant
I've never heard it called that before.
The Free Software movement, however, believes that code which protects the user's freedoms to use, modify and distribute it is intrinsically superior, and that people who wish to write code that does not respect these freedoms should not be aided by being able to use the work of those who do.
As such, an Open Source advocate would not mind, because the closed copy would quickly become inferior. A Free Software advocate would object, because their work would be being used for (in their view) unethical purposes (denying end users their freedoms).
I am TheRaven on Soylent News
You know, I'm absolutely tired of the BSD trolls that claim that the BSD license is "freer", not because I have a beef with the BSD, simply because your definition of "freedom" is ludicrous.
There are no absolute freedoms. Freedom to infringe on other's rights or freedoms gives more freedom to yourself, but limits it to other members of society. So long as there are things that cannot be owned or achieved communaly without side effects to others, freedoms have a limit, that is the actions that you cannot do so that others can do them.
The GPL definition of freedom is that a sofware and derivatives must always, under all conditions, be free. Yes, it a restriction to the developer who would wish to close up his source and use a GPLed piece of code, but it is an additional freedom to all the users who now have access to this source, which would have otherwise been denied.
Analogy time: the King is free to treat his peasants as dogs if he wished and if he has sufficient power to repress any opinions the peasants would have about that. The peasants, however, are limited by the freedoms the king has. Therefore the balance of freedoms for a more equal society would be that the king's freedoms be limited in order to allow the peasants to live their life.
So as you said, the GPL is also a social instrument, but it is no less free than the BSD; it simply distributes freedoms in a different matter. If you have a problem with that, use whichever license you wish to use. But don't go around accusing the GPL is limiting freedoms when it gives others freedoms that the BSD could never guarantee.
The Tao of math: The numbers you can count are not the real numbers.
If by that you mean "you have a different definition of what freedom is, therefore I don't like you" then sure, I'm a "BSD troll" or whatever.
GPL -> Distribution restrictions.
BSD -> No restrictions.
No restrictions -> More freedom.
More freedom -> Possible unsavory side effects that people choose to live with
Isn't logic great?
BSD has a similar one, except that it doesn't place restrictions on how that happens. No one can make BSD-licensed software "non free", it will always be available to everyone. The only difference is that it might not benefit from coerced third party improvements, but that's what you sign up for.
The Kool-Aid is strong with this one.
BSD licenses guarantee absolutely nothing. Here's the code, do whatever the heck you want with it. The perceived benefits to using the GPL are nice, but please don't insult people's intelligence by claiming they result in more freedom. A restriction to ensure X or Y is still that - a restriction. The distribution restrictions on the GPL are designed to further Stallman's social causes (some of which I actually agree with). If you feel that's fine, then by all means use the GPL. That's your choice.
GPL -> Distribution restrictions. BSD -> No restrictions. No restrictions -> More freedom. More freedom -> Possible unsavory side effects that people choose to live with
GPL -> Code will always be open and derivatives will stay that way
BSD -> Code can be closed off and new improvements to it can remain closed off forever.
Always open code -> More freedom
Sometimes open code -> Permanent loss of freedom with regards to that code.
Indeed, logic is great.
BSD has a similar one, except that it doesn't place restrictions on how that happens. No one can make BSD-licensed software "non free", it will always be available to everyone. The only difference is that it might not benefit from coerced third party improvements, but that's what you sign up for.
I never said that you can't sign up for that if so you wish, but code is always used within contexts, and when used in the context of proprietary software, any improvements on the code will be lost, any bug fixes will be lost, any added functionality will be lost.
Sure, some people will build upon it, but losing the obligation of putting the improvements back into the codebase means that it will eventually stagnate, and that the improvements that could have been used for the good of everyone who contributed can be denied at will. Look at FreeBSD with OS X: Apple got the foundation of their OS for free, and after that they simply closed up the rest at will. Perhaps the Apple folks got to improve their memory management, or add some new DRM techniques. Whatever they've done, the FreeBSD devs will never get to see it.
If they don't mind as users and developers to see their work used to create a proprietary, vendor-locked platform then it's their prerogative; as a used and dev I prefer to make sure that my code is an established base of constant improvement. With the GPL they're empowered and free to do that; with BSD new parties are empowered to do whatever and completely ignore original creators aside from the required attributions.
Notice that I'm not saying the BSD license is more free; it is equally free, but shifting freedom to new developers and vendors to be,IMO, lazy bastards and profiting for nothing, while GPL shifts it to original developers, contributors and users to get reciprocal treatment from others. You're free to think that the former is more important; I belive the latter brings greater benefits to everyone in the long term.
BSD has a similar one, except that it doesn't place restrictions on how that happens. No one can make BSD-licensed software "non free", it will always be available to everyone. The only difference is that it might not benefit from coerced third party improvements, but that's what you sign up for.
No one is coercing anyone here. If you had read and understoof the GPL, and it looks like you haven't, you'd know that the conditions apply only to those who want to redistribute software. If you want to keep your patches to yourself you can do that and it's your right, but if you're going to be using other's code to sell it or gain from it you have to abide by the creator's conditions. Going back to my point about freedom, perhaps as distributor you have less leeway regarding your changes, but your users have just gained the guarantee that they'll always be able to see and change the code. The BSD could not have done that.
BSD licenses guarantee absolutely nothing. Here's the code, do whatever the heck you want with it. The perceived benefits to using the GPL are nice, but please don't insult people's intelligence by claiming they result in more freedom. A restriction to ensure X or Y is still that - a restriction. The distribution restrictions on the GPL are designed to further Stallman's social causes (some of which I actually agree with). If you feel that's fine, then by all means use the GPL. That's your choice.
You hit the nail on the head. Th