The Future of Trusted Linux Computing
ttttt writes "MadPenguin.org tackles the idea of Trusted Computing in its latest column. According to author Matt Hartley, the idea of TC is quite reasonable; offering a locked-down environment offers several advantages to system administrators with possibly troublesome users. 'With the absence of proprietary code in the mix users will find themselves more inclined to trust their own administrators to make the best choices ... And so long as any controlled environment is left with checks and balances [like] the option for withdrawal should a school or business wish to opt out, then more power to those who want a closed off TC in an open source world." LWN.net has an older but slightly more balanced look at the TC approach.
But Linux and most Linux programs are already more "trusted" then Windows can ever be. From being open source, how can you not trust it? There are no surprises and if you feel so inclined, you can build everything from source to make sure that there isn't any malformed code in the binaries. So how is this news?
There is no "disagree" moderation, and troll, flamebait and overrated are not valid substitutes
There is nothing wrong with hardware assisted security if the owner controls all the keys and nothing can touch the trusted hardware without the owner specifically installing it (i.e. logging in as root/administrator and changing things).
Trusted Computing is only bad if the owner of the hardware does not have control over the software on the machine, the hardware keys etc.
Proof of this statement?
As I understand it, the meaning of Trusted Computing is not that the system administrator will be able to provide a locked-down system. That has long been available with ordinary security measures on Linux and other systems. Rather it means that even the system administrator - even the owner of the computer - will not be able to make the computer do what he wishes rather than what the record industry or movie studios want it to do. This is done by Intel or others supplying some special hardware which won't reveal its private encryption key unless it detects that authorized, signed code is running. Not authorized by the legitimate owner of the computer who is Intel's customer - no, that wouldn't do at all. Rather, that the code is signed by some third party such as Microsoft and there is a secure boot sequence to prevent 'tampering' (i.e., the computer's owner trying to reprogram his or her system).
I don't think the author of the article has understood what Trusted Computing means at all. He is just talking about thin clients and locked-down systems in school environments, which is not really the same thing.
-- Ed Avis ed@membled.com
Which is why if your that paranoid, you look at the source yourself and compile it from that source, its not that hard and there is no way that you somehow got code you didn't want. If you overlooked somthing that is your fault, you compiled it, you looked over the source, thats something you can't do in the Windows world with stealth updates and the like
There is no "disagree" moderation, and troll, flamebait and overrated are not valid substitutes
Read it again, you're not getting it. The issue is whether you can trust the compiler to produce machine code that corresponds to your source code.
You didn't evevn read the quote? The only way to bypass this is to hand build the compiler in binary. You won't *EVER* see the attack because it's in the compiler's binary, and the compiler puts it in the binary of any compiler it compiles - even if it is not in the source of the compiler it compiles.
Good luck with that.
34486853790
Connection too slow for X forwarding? Try "ssh -CX user@host"
Or are the users getting their CPUs' source code and recompile them? Or at least call their LinCPUx fans to do it for them?
Trusted Computing requires trusting the CPU manufacturer in the first place. And in this world, where the telcos have disclosed our conversations to the govt without us finding out but several years later, can we really trust that the government hasn't pressured the CPU makers to add a backdoor here and there?
Trusted Computing is practically closed, and incompatible with the spirit of Open Source/Free Software. Ergo, Trusted Computing cannot be trusted. Sorry.
... the computing trusts you!
I'm waiting for a "-1 somepeoplejustshouldn'tgetmodprivileges" meta-moderation.
If you are really paranoid compile the compiler with a different compiler. Or use a different compiler to compile two linux systems, and only allow logon to one from a remote shell from the second.
With the absence of proprietary code in the mix users will find themselves more inclined to trust their own administrators to make the best choices
Sorry, but I think that's putting your words into everyone else's mouths. Or fingertips, or whatever. The vast majority not only don't have this opinion about open vs proprietary code affecting how much they trust the choices their admins make, they also wouldn't have a freakin' clue as to what you're going on about in that sentence. The vast majority don't know what open-source is, how it differs from proprietary source, they don't know any reason why they'd care either way, and they'd probably give you a pretty funny look for attributing this philosophy to them.
I like Linux and open-source, and have an appreciation for it. But I don't trust my admin at work more when he talks about Linux than when he's talking about Solaris. It's his job to make the best choices of any and all products available, and I trust him to choose whichever is most appropriate for our company, even if he feels that happens to be a proprietary product. It's not my place to impose on him to only ever choose open-source, and there's cases in our work where open-source offerings are less ideal.
Quote: "(Column) - Despite my gripe about the Web site's sparse message..."
Great writing skills these guys possess, so much for reading the fucking article... (should have known better)
TC is a trap. It is there to exclude other operating systems besides windoze vista. It is there to take control away from you. It is BAD. We don't want more subjugation, thanks.
I won't ever accept NOT being the absolute owner of my own computers
That's good, but at work it's not your computer is it? The level of control you have over your computer at work is proportional to the intelligence of your employer. If you are unfortunate enough to work for a big dumb company, you will be fired for exercising your software freedom in any way. A less stupid company that uses free software will be able to give you the tools you need to get your job done without giving you complete control of your computer. Some workers need more freedom than others. Ultimately, the things the company needs to protect should only be accessible by people and machines that won't leak. Figuring out what really needs to be protected is the tricky part, but all of it should drive every company to free software.
The real problem with "trusted" computing is that it can force use of untrustworthy software and defeat it's original purpose. No company should ever trust it's real secrets with non free software. Control is lost when you have to "trust" a third party that keeps secrets from you. If you are using Windoze, you might as well email the information to Bill Gates.
What kind of secrets does your company actually have? There's customer information, location and movement of valuables, business plans and a host of other information that can be harmful to divulge.
None of this is an excuse to cut into your software freedom at home or even at work. It's just a problem of collective action and responsibility. When you work for a company, there are suddenly a lot of noses at the end of your arm.
DMCA, Hollings, Palladium. What might have sounded like paranoia is now common sense.
Ha, you're the first person I've heard mention this idea since the early '80s! Here's another similarly old, interesting factoid I've heard about the C compiler: The ASCII character set is no longer defined anywhere in the C compiler source code (which is written in C). In other words, '&' compiles to decimal 37 only because existing binary compilers know how to translate the '&' character constant.
Beer is proof that God loves us, and wants us to be happy.
A sufficiently motivated whatnow?
C-x C-s C-x k
How is this redundant? It might be obvious to some people, but I can't see it said anywhere else.
In Linux, there's no 'vending machine' mindset; they won't be charging every time you turn around, just because there's "no other game in town".
Under Windows? Forget it.
--- For a good time mail uce@ftc.gov
In short, this article aims to lure the unwary into gullible acceptance of TC with an illusion of completely deceitfully presented and impractical (no one except the mega-corps will ever get the access to the main TPM keys) applications.
than having proper permissions set up on a machine and doing a lockdown like what's built in to Gnome? Having proper permissions prevents people from installing shit and running programs that they're not supposed to. Using Gnome's lockdown feature prevents them from fucking up their DE.
Trusted Computing solves this how?
GENERATION 26: The first time you see this, copy it into your sig on any forum and add 1 to the generation.
How does the bugged compiler binary recognize the fact that it is compiling the source to a compiler?
In Thompson's case, he had it scan the source for recognizable text.
Defeat the "am I compiling a compiler?" test of the compiler binary and you are done.
All you need is a source code obfuscator. Randomize variable/function/file names, and insert red-herring calling sequences and recompile the source to the compiler to obtain a non-bugged compiler binary.
Writing a source code obfuscator (capable of defeating the compiler trojan's test) is much easier than writing the source to a compiler, and a great deal easier than hand composing a compiler binary.
In corporate networks, this will just lock down your PC a little more than it already is. Nothing to see here, move on please. It is in the home this shit gets interesting. Do you want your ISP, and possibly MS, to rule your PC? For the typical /. reader, the answer is a clear NO. But what about grandma? Imagine your ISP offering 2 kinds of subscription: a normal, "free" one and a "protected" one. The protected one is firewalled (or at least NAT-ed) at the ISP, with just "sensible" traffic allowed, like HTTP(S), SMTP to the ISP's own server, and with a limit on 50 emails/day. Throw in some MSN and Skype. Have the ISP use TC to inforce patches and anti-virus. I think grandma would be happy for it, it would extend the lifetime of her PC (slower buildup of spyware cruft) and for the rest of us it would cut back on Spam.
10 ?"Hello World" life was simple then
Indeed yes. The question "am I compiling a compiler?" is as undecidable as the question "am I compiling a program that will halt?" (Ken Thompson's suggestion is still interesting, though.)
... not to mention relatively clueless about encryption principles. Sorry if the following questions are glaringly obvious.
How does it work? How will it affect my machine if enabled (i.e. will I notice?)? Could an OEM (I hear Microsoft is distributing PCs nowadays) theoretically set up the TPM to lock down a system pre-purchase? What happens when the TPM blocks something/notices a different checksum?
You know, there is a difference between trolling and pointing out the flaws in your reasoning. Just saying.
Read the GP post again. Carefully. You have the source, Luke -- and, on the basis of your inspection, you missed the second-order instance of the problem of Trusting Trust.
(I don't know if the GP meant his or her post to be a direct attack on the frequent comment that "well, you have the source and can inspect it, after all", but if he or she did, congrats.)
Either a wanker or an extremely clever commenter on the true value of human inspection. I suspect the poster was a wanker, but, oh, my, do I hope that he or she was extremely clever.
Trusting "trusted" computing requires trusting hardware makers that can insert exploits. Trusted computing is therefore of limited value to end-users in a world where vendors and service providers are routinely leaned on to allow surveillance back doors.
If you have applications that you need to secure, in order to prevent, for example, misuse of tax filings or medical records, you can do it using Web applications, or other thin client technologies combined with physical security of client computers. There is nothing that can guarantee stopping someone copying data manually from a screen display and smuggling it out of an office, so there are practical limits to securing data beyond which additional technology is pointless.
There are some theoretical cases where trusted computing could benefit individuals. But, in practice, it's all about someone else trusting your hardware to rat you out. Most of the money flowing in to trusted computing comes from those kinds of uses. "Trusted computing" has rightly earned distrust.
I wrote parts of this stuff
Trusted computing also enables a real market in CPU time. You can sell your spare processor cycles since the trusted machine can attest to the fact that this really was the result of the code you sent out. Similarly to have software agents that run on unknown people's servers this would be necessary.
It would also be useful to implement true ecash schemes and in allowing true p2p based virtual worlds/games with safegaurds against cheating.
In short the technology offers a lot more promise than mere security and eventually it is a good thing for everyone to have. In fact I think it potentially offers more benefits for a stable OS like linux than windows. You can't blame the technology for the fact that some idiots would have us use it for DRM or other customer control. The correct response is to embrace trusted computing and reject DRM...but in the real world perhaps it is better if we wait a bit longer for TC until the RIAA and other groups are forced to learn that selling music unprotected is the way to go.
If you liked this thought maybe you would find my blog nice too:
totally off topic - I was recently involved in a test at work to trial some new software - 180 users were sent a document detailing how to install and configure a VPN application - the instructions contained some bad instructions - which if followed to the letter - would block http access - of the 180 users installing the software - only 3 reported the problem - 177 people did not read the instructions - or read them but did not follow them!
Unfortunately there are several DIFFERENT, INCOMPATIBLE concepts being bandied about under the name Trusted Computing. This new "Trusted Computing Project" took on that name seemingly without being aware that there was substantial work already under way on a different concept with the same name.
Perhaps to try to remedy the confusion, we can distinguish between TC as proposed by the Trusted Computing Group and other forms of TC. The TCG is an industry consortium with Microsoft, Intel, HP etc., dating back several years, originally called TCPA. Their proposal has always been controversial but IMO misunderstood.
TCG's flavor of TC is fundamentally open. I would call it Open Trusted Computing, OTC. It does not lock down your computer or try to prevent anything from running. It most emphatically does NOT "only run signed code" despite what has been falsely claimed for years. What it does do is allow the computer to provide trustworthy, reliable reports about the software that is running. These reports (called "attestations") might indicate a hash of the software, or perhaps a key that signed the software, or perhaps other properties or characteristics of the software, such as that it is sandboxed. All these details are left up to the OS, and that part of the technology is still in development.
Open Trusted Computing runs any software you like, but gives the software the ability to make these attestations that are cryptographically signed by a hardware-protected key and which cannot be forged. Bogus software can't masquerade as something other than it is. Virus-infected software can't claim to be clean. Hacked software can't claim to be the original. You have trustworthy identification of software and/or its properties. This allows you to do many things that readers might consider either good or bad. You could vote online and the vote server could make sure your voting client wasn't infected. You can play online games and make sure the peers are not running cheat programs. And yes, the iTunes Music Store could make sure it was only downloading to a legitimate iTunes client that would follow the DRM rules. It's good and bad, but the point is that it is open and you can still use your computer for whatever you want.
This is in contrast to some other projects which may or may not call themselves TC but which are focused on locking down the computer and limiting what you can run. The most familiar example is cell phones. They're actually computers but you generally can't run whatever you want. The iPhone is the most recent controversial example. Now they are going to relax the rules but apparently it will still only run signed software. This new "Trusted Computing Project" is the same idea, it will limit what software can run. Rumors claim that the next version of Apple's OS X will also have some features along these lines, that code which is not signed may have to run in sandboxes and have restrictions.
This general approach I would call Closed Trusted Computing, CTC. It has many problematic aspects, most generally that the manufacturer and not the user decides which software to trust. Your system comes with a list of built-in keys that limit what software can be installed and run with full privileges. At best you can install more software but it is not a first-class citizen of your computer and runs with limitations. Closed Trusted Computing takes decisions out of your hands.
But Open Trusted Computing as defined by the TCG is different. It lets you run any software you want and makes all of its functionality equally available to anyone. P2P software, open-source software, anything can take full advantage of its functionality. You could even have a fully open-source DRM implementation that used OTC technology: DRM code that you could even compile and build yourself and use to download high-value content. You would not be able to steal content downloaded by software you had built yourself. And you could be sure there were no back doors,
Without informing anyone. External entities should be free to *request* specific support software, but the user should always have the right to override that request.
...about the ramifications (both good and bad) of TC can be found here.
The main problem I have with TC is the fact that it removes control over the hardware from the user and gives it to a 3rd party entity.
When I purchase hardware, I expect to have full control over it's capacities. If the hardware is capable of doing something, I should be able to do it. There's something a bit eerie about giving your computer a command/instruction and having it come back and tell you it could do it, but that it won't (2001: A Space Odyssey anyone!?).
My worry is that TC misinformation will be pushed so much that the idea of the user being in control of their hardware will be considered old fashioned. Well, it may be old fashioned, but it also has the side effect of being correct.
Now, I do think that TC has a place in the corporate world where there is no expectation of employees being able to do whatever they want on the computer (businesses have a right to control their own equipment). But the propagation of TC into the public or home is what doesn't set well with me.
Faith is a willingness to accept something w/o complete proof and to act on it. Reason allows you to correct that faith.
I wonder how much someone paid for his opinion... There's a reason why that site is barren, and the forums are filled mostly admin created polls.
There is a chance that the users noticed the problem and then found the "correct" way to install the software and didn't bother reporting it.
It's quite helpful to watch as a primer/refresher: the wonderful animation about Trusted Computing. Simple, good, understandable.
Insert
I'm having trouble understanding what you mean by "software freedom". Computers are provided by employers to manage tasks and handle data related to your function within the organization. Where exactly does your freedom come into play there? And what does free software do there that "Windoze" doesn't?
You don't say.
Sure it is, if it's company-provided hardware. You really have never had a job at a real company, have you?
You sound like those (former) disgruntled employees at the "big dumb stupid" companies that won't let you exercise your "freedom of speech" by letting you install Kazaa and BitTorrent on the laptop they gave you to do your job. Down with the man!
Web2.0: I love when people Flickr my cuil and digg my boingboing until my google is reddit and I start to yahoo
Parent is not Troll.
And yeah, Trusted Computing it about not trusting the user. You dont think that these companies are gonna get together and say 'We know what is best for you' at some later date when we're all stuck into the Trusted Computing format and lock us all down. Kiss Open Source goodbye because someone will make the argument that Linux cant be trusted because its Open Source and a PHB at one of these hardware companies will (stupidly) agree.
09F911029D74E35BD84156C5635688C0
+2 Troll is Slashdot's way of saying groupthink is confused
..when the year of the Linux desktop happens, Then you'll be sorry!
Besides, there are two problems with these "boot security" features:
First off, just because you sign your kernel doesn't mean it's secure. If your entire system is controlled by an insecure OS, and if somebody exploits a hole, they can still tell it to do whatever they want. An attacker can still use your key to sign or decode anything they want, even if they can't read it from the TPM hardware.
But, for the sake of argument, say that this is still a step up. You still don't need a TPM chip for that; you can build crypto hardware with a write-only keyspace, and throw in user-controlled tripwire services on boot, without adding a manufacturer-fixed unique identity key in a tamper-resistant chip. The only practical use for that is the kind of ubiquitous DRM games that TPM was designed to deliver in the first place.
The only way I'd buy hardware with security features like this is if the user (with physical access to the hardware) was able to completely scrub all identity information from it, and generate a new identity key -- tabula rasa. Of course this means that the whole thing could be simulated in software, and nobody else could be certain you were running a particular piece of hardware with hardware-enforced constraints on the software configuration. Which, of course, is the entire goddamn point.
Did you know that The TCG/TCPA specifications create a technical definition of the "owner" of device? It could be the manufacturer, the reseller, a sysadmin, a user, or someone the user loans the machine to. It all depends on who "takes ownership" (also technically defined in the spec) first. The "owner", in this sense, is the one who gets to specify which signing keys are needed to sign code that the owner wants to allow to run. This can include vendor keys, and even a user's own signing key.
Whether TC is considered "evil" always seems to depend on differences between who uses the device, and who "owns" it in the TC sense. If the TC "owner" matches the consumer who bought the device, there's little problem. But if the TC "owner" is actually the vendor of the device, users can get the shaft if the "owner" elects to restrict native capabilities of the device.
The case of enterprise sysadmins taking "ownership" of company devices away from users is a borderline case that most people can go along with. After all, the device is company property on loan to employee users.
More here:
http://n8o.r30.net/dokuwiki/doku.php/blog:trustedcomputingnotaryinabox
I'm sorry... what?
a sufficiently motivated nigger could painstakingly review the machine code
Was that really necessary ?
This piece of propaganda that you are spouting is indeed 'Interesting' and 'Insightful' in how clever it is.
You are right that TC only provides a signature which cannot be forged. But if you the user cannot forge the signature of the result of the cpu cycles that the computer runs - then anyone can write up software that does X and Y and Z only, ONLY, when you provide signed data to them - and wont work if you don't ...
And thats the point! That is exactly what everyone will immediately do - the banks, the commercial websites, government websites, software provides, music and movie industry - they will start making products and services that ONLY work if they are certain that they work the way they want them to - ie. crippled in a way to provide maximum profit, force you to provide details of yourself and what you are doing etc. Basically what ever they want - you might technically have a choise of 'controlling' your computer - but in practice you won't.
Trusted Computing might 'only' do one innocent thing - but it ENABLES the corporations/government/contentproviders to eventually and effectively take over your computer.
So by definition - and indeed it is probably mathematically provable even - that if the user cannot effectively 'forge' data coming out of his CPU, then all forms of Trusted Computing, however 'Open' they are - are unTrustworthy - and people who promote the idea, are Treasonable!
www.tribalnetworks.org - helping tribal people around the world to own their own means of high-tech communications
The problem, as you've said, is very much "who gets the key."
My problem with it is that I believe that the hardware manufacturers will consider it to be "their" computer and will keep the key from me. So that "my" machine will really be theirs, because they control the keys.
I have no interest in giving up control of a machine I've bought and paid for to any third party. And therein lies the rub: the technology can be used for both good and evil, but I'm pretty sure we're going to see the latter. And I do not trust the "free" market to correct for this--the whole point of this is to remove the consumer's ability to choose.
Y'know, people keep talking about document control, like it's a good thing.
Well, how about this other side of this sword, like when your boss gives you an order, via e-mail, to do something that is unethical, illegal, or immoral.
You think you've covered your ass, because you've got this order in writing. But it deletes itself after X amount of time, and anyway, it isn't readable on any computer not designated by the author/creator.
What about whistleblowing? Doesn't this make it a lot harder to take, say, a document written by a government official, and leak it to the media?
People keep talking about 'document control' in the context of things like when hackers break in and steal people's credit cards or health records or something.
This technology, even the most benign aspect of it (doc control) has the power to make secrecy a lot easier to execute.
I'm not sure that is in any way a good thing for a democracy.
The plural form of "anecdote" is "anecdotes", not "evidence".
...and I want to protect trade secrets from malwares, harddrive thieves and malicious employees. Then it is very reasonable for me to want the TPM to be hackable by myself but not by any of my employees, so that I don't need to trust any third party to properly manage my endorsement keys, and I can be sure that my encrypted documents are still accessible even if something breaks horribly.
The ability to regenerate the key (and that the majority of the users actually does it) is important. The initial key might have gotten leaked by a bad manufacturer, might identify me in a way I don't like, and the previous owner of the computer might have gotten the key signed somewhere and subsequently earned a bad reputation with it. In any case I have little control over it. After generating a key, I can get it signed by whoever I wanted to be trusted by, e.g. an online game server, a distributed computing project, my employer, or even myself if malware-prevention is the goal. In some cases the trusting party (e.g. my employer or myself) may want a copy of the private key, so there should be the option that the private key be copied somewhere at key generation time (and never again, so the trusting party knows that no one else can hack the TPM). Since I may want to assume multiple identities, to be trusted by multiple different parties, all with the same computer (e.g. I may not want anyone to know that two user accounts in two different online games are both operated by me with the same computer, even if the same company runs the servers for the two games), the key had better be pluggable, particularly when there is no commonly trusted third party. In other words, the TPM I might want is not much different from a smart card, except that it has a tamper-proof way of hashing the hardware and software. This hashing is meant to be used for things like cheat-prevention, distributed computing and enterprise system management, and not for unsuitable purposes such as forcing the user of a website to use a certain operating system or browser. Of course, an ordinary website should not need to have my key signed, anyway.
To the proponents of Trusted Computing, Quit trying to pull the TPCI wool over our eyes!
If I want to run OPEN SOURCE software, because I can re-compile it, because I can change it, because I can fix that bug that no one else will fix because I am one of three people in the whole world who ever see it. When I re-compile my kernel to fix that bug because I am sick to death that my laptop crashes every time I visit my Bank Site. I re compile it with the fix (or with any other change I like) Trusted computing will either:
A: Flat refuse to load my shiny new kernel, because it can no longer be decrypted.
or
B: Allow my shiny new unsigned kernel to load, but now my Bank will not speak to me because I am no longer TRUSTED.
Who has to sign my shiny new kernel? The BIOS maker? Microsoft? Some random authority? Who will have to read my source code to be sure I have not done anything untoward and to whom I will have to pay a bribe er.. Fee. Perhaps a substantial fee. Surly I can't sign it myself - I may be an eeevil terrorist pirate trying to build myself a DRM busting back door. NO some "trusted" entity will have to sign it for me. That means I will have to ask someone's permission TO USE MY OWN COMPUTER.
If I have to ask permission of a third party to use my own computer, it is not "my computer" any more.
You can't have it both ways - either I trust (and control) my computer, or the Music/Movie Industry trusts it because they are able to control it (and me).
You were saying if I got the Master Key I could override any part , but if I do override then once again my machine is not trusted and I become a second class citizen on the Internet, If I am even allowed on. I can no longer bank at my bank, I can no longer see or hear any media.
What use it it to have the source code if you compile it, but you can't run it.
It all still simplifies down to the fact that either I have the keys for my machine If so the content industry could not trust me or my machine.
Or a third party has the keys, in which case I am no longer in control of my machine. It is not "My machine" anymore. I can no longer compile and run my own software. I can only run what my drm masters deem "trustworthy".
there are two definitions of "trusted computing", and it depends on who is doing the trusting.
the first definition basically boils down to "we don't trust users" - and is the version of trusted computing that you're describing.
the second definition basically says "we want users to be able to trust their computers and be able to do what they want without worrying".
it should be fairly obvious which definition that a linux-based, free-software-backed distribution will go for, especially with the backing and quiet involvement of a couple of heads of police departments, and several professors from royal holloway.
Hello Good Comment---- dashyaoo
I remember a couple of years ago I was very concerned about this matter, trusted computing sounded like a nightmare, I even talked about it with all my friends, and suggested they should boycott those hardware vendors that were working on or endorsing this project... then suddenly I forgot about it... I can't tell if I simply stopped caring about avoiding the changes and starting to trust I'll be able to adapt (which is rather selfish, but hey, pragmatic), or if it's the certainty that someone will be working on alternatives and possibilities, either way, I'm no longer worried.
Seriously, this is not an option. The reason we have so many different distributions of linux is because these parties all tried compiling all the code, and dealt with the issues at building machines to achieve certain goals. There is a great deal of manpower on these attempts and frankly I don't think one person could reproduce this reliably. Sure you 'could', but would you? This means that it's much more practical (and realistic) that most people are downloading full distributions. Of course they can still get the source and view it, but what if it's written in a language you don't understand? What if you don't understand the programmers methods? Sure, a google here and a google there, and you get your answers, but likely someone building the distro had a similiar situation and worked it out. When you DIY OS you will have to figure out all these 'bugs' again. Seems like a waste of time to me. But even now it's quite obvious that most users will not compile their OS's. This is unrealistic, even for the paranoid. Of course some have taken the approach of a secure trusted platform, but again I'm looking at a distribution. Even if one person figures out a unique method to do the same, what are the odds that it will remain a secret? So, is it really a practical reality that one person can 'compile' a modern linux OS? No. So you need to get help. Even TWO people means that trust needs to be established if the project is to move forward. This means a trust relationship has to be established. Now, the paranoid is freaked out again since there is a 'possibility'. I really feel for the paranoid, it's gotta be rough. Today's computing is unfortunate in some ways, but we have to trust other's code and typically without any prior examination.
Jeruvy