[Q] is CF-Kernel (by chainfire) "clean", "safe" and open source? - Galaxy S II Q&A, Help & Troubleshooting

hi there,
I'm aware that the CF-root-kernel is used a thousand-times by many people but this makes this question even more important: has it been completely reviewed by other developers in fact because the source is open?
don't get me wrong, I really don't want to allege anything to chainfire, but since it's the kernel, the core of the system, this component should be fully reviewed and proofed as clean and safe. otherwise no droidwall can ever detect e.g. silent data transmissions (sent on kernel-level) or spy-attack etc....
so if the whole CF-Root-Code is released e.g. on github I think things like that could be revealed/proofed. if it's completely closed it's just a question of trust...
unfortuanately it's seems like it's kept secret... because https://github.com/Chainfire says "Chainfire doesn’t have any public repositories yet"...
does chainfire keep his CF-Root-Source closed and secret and due to that could theoretically put some secret kits in there?
so I'd like to know if the CF-Kernel (made by chainfire) is open source or alternatively chainfire released his source code, and this code could and has been reviewed by others (e.g. experienced senior members)?
btw: if it's closed sourced and due to this potentially "unsafe"... are there any other fine root-kernels with cwm which are open source and due to can be fully trusted?

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Hullo.
Well some developers like to have their hard work protected from stealing so they are using closed source approach. You should not fear using a kernel or ROM when it's downloaded from the official site, even better with md5 checksum.
Sent from outer space by aliens on tapatalk using SGS2

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AJ.Rockwell said:
Hullo.
Well some developers like to have their hard work protected from stealing so they are using closed source approach. You should not fear using a kernel or ROM when it's downloaded from the official site, even better with md5 checksum.
Sent from outer space by aliens on tapatalk using SGS2
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it doesn't provide any security if "it's downloaded from the official site" when the source of the "official site" has never / could never been reviewed. neither does a md5 checksum... if CF-Root is really closed source it's like blind faith and I think when in comes to kernels, the core of your phone... blind faith isn't a good idea...

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CF-Root has no patches to the actual kernel, it's "only" the initramfs that is edited to give you everything you ask from his kernel.
Open a terminal, type "cd /" and off you go inspecting everything.
OpenSource would give you not a single bit of more "secure feeling" - what if the backdoor is simply not included in the source, but built into the binary release?
May I ask what exactely you are afraid of?
And on a sidenote:
Yes, I did a rather deep "walk through" the files of CF's kernel and you have no reason to believe and trust me more than CF himself, but let me state it anyways:
It's totally cool, save, no backdoors, everything is A-OK!
Hope that helped a bit

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A thought about why would well known kernel/ROM devs place backdoors in their products is way beyond me. There surely is a botnet full of siyahkernel users haha jk... Just take it easy, CIQ is more of an issue lately..
Sent from outer space by aliens on tapatalk using SGS2

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AJ.Rockwell said:
There surely is a botnet full of siyahkernel users haha jk...
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*LOL*
That one really made me laugh XD

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at first, thank you for your reply!
HellcatDroid said:
CF-Root has no patches to the actual kernel, it's "only" the initramfs that is edited to give you everything you ask from his kernel.
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ok, but how can this be checked? how can it be proofed, that is the original kernel? can I proof it in anyway for my self? and maked shure that there is no backdoor in it?
HellcatDroid said:
initramfs
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because I want to learn more... what is "initramfs" in particular?
HellcatDroid said:
Open a terminal, type "cd /" and off you go inspecting everything.
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sorry that I ask so silly, but what will this command reveal, other than the content of the actual folder? how does this help to inspect the kernel in detail?
HellcatDroid said:
OpenSource would give you not a single bit of more "secure feeling" - what if the backdoor is simply not included in the source, but built into the binary release?
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yeah, there you're right, what brings me to the question (see above) how the compiled files can be checked/verified/proofed?
HellcatDroid said:
May I ask what exactely you are afraid of?
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just like you mentioned... something like backdoors, secret data transmissions which can be revealed because they happen on kernel-level...
HellcatDroid said:
And on a sidenote: Yes, I did a rather deep "walk through" the files of CF's kernel and you have no reason to believe and trust me more than CF himself, but let me state it anyways:
It's totally cool, save, no backdoors, everything is A-OK! Hope that helped a bit
Click to expand...
Click to collapse
hehe, thats right, I don't know neither you nor chainfire... although I appreciate you posting.

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AJ.Rockwell said:
A thought about why would well known kernel/ROM devs place backdoors in their products is way beyond me. There surely is a botnet full of siyahkernel users haha jk... Just take it easy, CIQ is more of an issue lately..
Sent from outer space by aliens on tapatalk using SGS2
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Click to collapse
so I think it's no so odd to ask about the trustworthiness of CF-Kernel as well, isn't it? especially if it's kept secret by cf... no one should blind faith, when it comes to kernels...

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In loose order of your questions above:
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You can grab one of the kernel initramfs (see answer to what that is below) dumpers, most of them split the zImage into the actual kernel (code) and said initramfs.
The kernel (code) image should be almost 100% identical (almost due to some headers and those things that might be different due to the edited initramfs).
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When the kernel is started, there is nothing - like on god's first day during creation (don't laugh, I kinda mean it like that! )
There is no system (that's still sitting somehwere on the flash or HDD or wherever) and nothing.
But the kernel needs a place to start booting up the system and to load additional kernel (driver) modules from that are not statically compiled into the kernelcode itself.
So the zImage has an image of a small, base filesystem that is placed into a RAM disc just before the kernel code is started (usually done by the bootloader).
This filesystem is the "initramfs" (short for "initial RAM-disk filesystem").
In the SGS2 case (or Android in general) /system and /data (and some others) are mounted into this so the system can finally be booted up by the kernel.
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with "cd /" you change to the uppermost, "root" directory of the system, it's where everything starts in Unix/Linux world and where the mentioned initramfs is.
So by browsing the folders in there (except for additionally mounted in one's like /syste, /data, /efs, /tmp and some more) you are exploring the contents of the initramfs - it's not really secret.
Though, it can be made more secret, of course.
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there is about one bazillion tools and apps that can compare files

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CF Root is the most vanilla out of all the Kernels. It is just the Samsung stock Kernel + root. It has been tried by thousands of people without a problem and is 100% clean, safe and open source.

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if in doubt
chainfire specifically mentioned that his kernel is taken from the stock samsung firmware, modified to get "root", CWM and busybox. he didn't mention of any specific tweaks (to make it better than stock).
so when in doubt, after rooting (and used up all the goodies of CF-root kernel), flash back to stock kernel. he included in his post how to do it.
have you reviewed the stock kernel's source? is it safe?

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Paranoid much ? I'd be more worried about crap (Carrier IQ, etc) your telco has put on their particularly branded phone (particularly if you have a US variant of the SGS2) than anything Chainfire might do.

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if youre so afraid, stay stock
oh and on a side note, theres this website called Google (go to www.google.com)
and search for answers.

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Any app you download from the Market may have backdoors in them. Any app with network access may potentially connect back to the developer and send all sorts of information, or even files, back.
So, if you want to be "safe", you have no choice but to stick to the base stock software. But then ... maybe Samsung could have placed stuff in your phone doing stuff you may not be happy with.
And we can't forget Windows OS either, how many time may that connect and send info and files back, and have various backdooes we don't know about ?
As it has been pointed out, simply having "open source" doesn't guarantee you anything, unless you compile that yourself as well as.

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Break out the tin-foil hats

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Once u hear its chainfire... its safe. Good dev.
looks like an iphone but powered by android baby!!!!

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It's a legitimate question. We are flashing modified software to our phones made by others. It can be a security risk, anyone could modify a rom and let it send privacy information to his server. It is someting we should consider everytime we flash a rom. That we always presume that the roms on XDA are safe, does not rule out the possibility that it will happen in the future. Smartphones are getting more interesting for people with bad intentions.
As mentioned above, it's the same with installing apps from unknown sources and even the Android Market.
But if there is any developer I would trust, it is Chainfire. He has done more for XDA then most of us ever will.

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Thanks for all the replies!
postfatal said:
CF Root is the most vanilla out of all the Kernels. It is just the Samsung stock Kernel + root. It has been tried by thousands of people without a problem and is 100% clean, safe and open source.
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Click to collapse
Yes, I'd agreed that thousands of people use it without even think about it. I know / read that it's a very common and known root-kernel. but I think precisely because the latest scandals with spysoftware... it's important to look into these CF-Kernels. unfortunately I'm not able to review it myself, because I'm not that into Unix-Coding. What makes you so shure about it's really "Samsung stock Kernel + root"?
ngokula said:
chainfire specifically mentioned that his kernel is taken from the stock samsung firmware, modified to get "root", CWM and busybox. he didn't mention of any specific tweaks (to make it better than stock).
so when in doubt, after rooting (and used up all the goodies of CF-root kernel), flash back to stock kernel. he included in his post how to do it.
have you reviewed the stock kernel's source? is it safe?
Click to expand...
Click to collapse
Yeah, anyone can say anything he wants, like "chainfire specifically mentioned that...". yeah he might have mentioned it, but if his kernels aren't reviewed before they're used by thousands of people... hmm... as I mentioned I really don't want to allege anything to chainfire. I think he's doing a great job. I just wanted to ask, if there could be something in it, or if there are reviewd and proofed, not only used with blind faith...
Touché! The stock kernel could be unsafe as well. but the included "stock" kernel is not from samsung directly, but from chainfire as well... so it's the same source... that doesn't make it any better...
MistahBungle said:
Paranoid much ? I'd be more worried about crap (Carrier IQ, etc) your telco has put on their particularly branded phone (particularly if you have a US variant of the SGS2) than anything Chainfire might do.
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yeah, you're right there. but wouldn't it be better if there's at least nothing added even more?
androidkid311 said:
Once u hear its chainfire... its safe. Good dev.
looks like an iphone but powered by android baby!!!!
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Click to collapse
yeah I have the same "feeling" about this, but this is just blind faith on my side. is is blind faith on your side, too, or do you have any hard proofs about this?
Lennyz1988 said:
It's a legitimate question. We are flashing modified software to our phones made by others. It can be a security risk, anyone could modify a rom and let it send privacy information to his server. It is someting we should consider everytime we flash a rom. That we always presume that the roms on XDA are safe, does not rule out the possibility that it will happen in the future. Smartphones are getting more interesting for people with bad intentions.
As mentioned above, it's the same with installing apps from unknown sources and even the Android Market.
But if there is any developer I would trust, it is Chainfire. He has done more for XDA then most of us ever will.
Click to expand...
Click to collapse
thanks for your approval. and I agree on you, too. I think only a few people even have a slight thought about what they flash there on their phone... I think this should always be peer-reviewed by professional devs, before its possible to download such files...

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I personally would rather see people question things like this. People should NOT download crap from nobodies...
So to answer your question about CF-Root, here's why it's safe...
1) CF-Root is NOT a recompiled kernel. It's the 100% totally stock kernel. You can split the zImage into ramdisk and kernel image, and compare the kernel image SHA1 with that of the split stock zImage. If it's the KL1 CF-Root, compare to the KL1 stock. You'll find the two match identically.
2) CF-Root is a modified initramfs, to give functionality such as auto rooting, and much more. If you take your stock initramfs, and compare it to the CF-Root one, you can see the changes for yourself. It's shell scripts (bash), so it's plaintext.
You'll see binaries added to the initramfs - busybox for example... So go compare that to the generally available busybox and you'll see it's fine
In short? Yeah it's fine. In long? It's fine for the reasons above

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pulser_g2 said:
I personally would rather see people question things like this. People should NOT download crap from nobodies...
So to answer your question about CF-Root, here's why it's safe...
1) CF-Root is NOT a recompiled kernel. It's the 100% totally stock kernel. You can split the zImage into ramdisk and kernel image, and compare the kernel image SHA1 with that of the split stock zImage. If it's the KL1 CF-Root, compare to the KL1 stock. You'll find the two match identically.
2) CF-Root is a modified initramfs, to give functionality such as auto rooting, and much more. If you take your stock initramfs, and compare it to the CF-Root one, you can see the changes for yourself. It's shell scripts (bash), so it's plaintext.
You'll see binaries added to the initramfs - busybox for example... So go compare that to the generally available busybox and you'll see it's fine
In short? Yeah it's fine. In long? It's fine for the reasons above
Click to expand...
Click to collapse
thank you very much! this is a well formulated and consistent answer! so chainfaire doesn't have to release his source, cause it's completely plain text... If that's true, it could be reviewed (and was I think), and that's fine.