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One Laptop Per Child Security Spec Released
Posted by
ScuttleMonkey
on Wed Feb 07, 2007 05:41 PM
from the no-school-like-the-old-school dept.
from the no-school-like-the-old-school dept.
juwiley writes "The One Laptop Per Child project has released information about its advanced security platform called Bitfrost. Could children with a $100 laptop end up with a better security infrastructure than executives using $5000 laptops powered by Vista? 'What's deeply troubling — almost unbelievable — about [Unix style permissions] is that they've remained virtually the only real control mechanism that a user has over her personal documents today...In 1971, this might have been acceptable...We have set out to create a system that is both drastically more secure and provides drastically more usable security than any mainstream system currently on the market.'"
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But what about DCOM in my ActiveX? (Score:5, Funny)
I'm thinking it would work well to implement such a feature so that the writing widget can talk to the chat widget and the spreadsheet widget. I was planning on calling it, Dynamic Communication Over Methods, or DCOM for short.
Now I'm bummed!
Re: (Score:3, Funny)
It's worse than that, it prevents app partitioning (Score:5, Insightful)
Actually, it's even worse than your funny (but accurate) comment suggests:
In the Unix model, applications are often built out of multiple cooperating processes, each of which is isolated into its own address space, with strong barriers between processes enforced by the MMU hardware. This makes each separate part more robust, more comprehensible, and more secure.
In contrast, when Bitfrost throws away the ability of programs to talk to other programs, it is intrinsically encouraging a monolithic approach to program design, which is a huge step backwards both for security and for complexity management.
Bitfrost is right to deny free access by programs to a user's filestore objects as an important part of its new security framework, but if the price for that is to disallow strong application factoring and partitioning into separate but communicating processes then the cure may be worse than the disease.
Parent
Where does it say that? (Score:4, Informative)
I read the whole article but I don't remember reading that anywhere.
I read some stuff about programs not being able to look at other program's files, but that's not the same thing at all.
I'm pretty sure OLPC uses IP, and that means sockets. If you've got sockets then you've got inter-process communication.
Unless you've got proof that OLPC doesn't have named pipes, etc. then I suspect you're pulling misinformation out of somwhere the sun don't shine.
Parent
Re:One Treacherous computer per Child (Score:5, Interesting)
If you'll RTFA (yeah, I know, no one does that...), the system can be completely disabled if the user so wishes. The purpose of the PKI is not to force someone to only use certain software; it's to help ensure that security updates haven't been compromised before getting to the laptop.
As for installing another Linux distribution, would that even be possible at present? I doubt any other distro would run properly on the OLPC's custom hardware without extensive modifications. Sure, you can argue "but they should have the freedom to break it if they want" -- and they do, as the article says. All this stuff can be disabled. Overwriting the OS should disable the anti-theft daemon, since the anti-theft system is implemented entirely in software.
I think the anti-theft provisions that turn the laptop into a brick are a bit much, but the actual spec (which I'm sure you didn't read either, as you're misquoting it) notes that the lease period can be set to any value (chosen by the country manager who distributes the laptop). A lease period of 3 months is given as an example. And in extreme circumstances, a USB drive with credentials that can be used to extend the lease period without needing access to the internet.
At any rate, the spec mentions that the anti-theft system is only installed and enabled on the request of the country purchasing the laptops. So it's not like the OLPC group is forcing this on anyone. If the countries are spending the cash on these things, I think it's reasonable that they should be able to try to protect their investment.
I have a decent number of reservations about the entire OLPC program, but c'mon, at least don't make up shit about it that isn't true.
Parent
RTFA - this is not DRM or Trusted Computing (Score:5, Informative)
If you RTFA, they specifically designed the security model so that children could write their own apps which can do *anything*. But they set up some defaults (which can be overridden) to protect the system.
What they are aiming at is a way to set sensible limits per-program, at install time: So at install time, a package (they call it a bundle IIRC) has a list of specific rights that the program will need in order to do its job. If the bundle doesn't ask for a certain right at install time and tries to use it later (because, say, it was maliciously modified), it will be denied.
If an app *is* signed by OLPC, it can have any right that it specifically asks for at install time. Otherwise, there are some rules about what subsets of rights are allowable together (i.e. asking for certain rights will exclude certain others by default). But again, the whole thing can be overridden.
This is nothing like Trusted Computing or DRM. It's more like a wrapper around SELinux (I don't know if that's actually how they implemented it).
Parent
RTFA (Score:3, Insightful)
Sharing programs (binary executables) with your friends is easy and encouraged. All programs are severely sandboxed by default, so there is no problem unless the attacker finds a bug in the CPU hardware. The sandboxing is really well thought out; an app bundle (install package) can request camera access or net access but not both. Apps never get more permissions than they requested at install time, excepting when an advanced child
Yes, better security... (Score:5, Funny)
Re: (Score:3, Insightful)
Drastic? (Score:4, Insightful)
Drastic?
I'd be willing to work toward "acceptable" or "workable".
The problem with "drastic" is that it often envisions high frontier technologies when all that is needed is a really well thought out plan.
If the UNIX system worked well for nearly 40 years, and was fairly simple to implement, then another 40 years *might* be had with something equally simple.
Re: (Score:3, Insightful)
If the UNIX system worked well for nearly 40 years, and was fairly simple to implement, then another 40 years *might* be had with something equally simple.
Nah, we'd need something drastic to fix what we currently have. Linux/Unix wouldn't help if it became dominate and users gave out root passwords to every program that asked nicely for them. I've just read the intro, an
Re:Drastic? (Score:4, Insightful)
Parent
Re:Drastic? (Score:4, Funny)
Parent
Re: (Score:3, Insightful)
I just had to su change the permissions on a config file so I could change the settings on vegastrike to steer with the mouse. With your model (yes, I detected the humor) developers would design around the "they can just hit the button" principle, even when they are writing things to "just work" remotely. Security will happen when people learn:
Sand dunes (Score:4, Insightful)
The article talks about the picture-viewer not being able to access the web. What if I *want* the picture-viewer to access the web ?
I tihnk I take issue with 99% of applications not needing interaction. If that's true (and I doubt it to be honest), I think that's a failing of software today, not a goal to be strived for. Most of the apps I use daily require web/internet access. I think that's only going to increase over time.
Simon
Re:Sand dunes (Score:5, Informative)
The document said that it was not possible for the application to request P_DOCUMENT_RO access and network access simultaneously during installation.
But it also said that it was perfectly OK for a user to go in and explicitly grant P_NET access via the GUI to an application with P_DOCUMENT_RO access, thereby giving you an application that is able to read your images and mass upload them to teh interweb, but only to those users who know enough to explicitly use the security interface.
Also the OLPC or local government could issue a signed XO package that offered that functionality to younger children.
Parent
More Power to Em (Score:3, Insightful)
This really is a good idea and hopefully others will follow suit. Applications simply are not all trustworthy and the assumption that they are is a huge failing of most modern OS's. I hope they get this right. There are a lot of pieces here no one has perfected. They need restrictions, proper services between applications and to them, granular levels of trust, or ACL profiles, means of easily and accurately assigning those trust levels, and a well crafted UI for programs that want to override their trust level. Best of luck to them.
Re:More Power to Em (Score:4, Informative)
Plus it's only a matter of time before the first solitaire clone ships with a "request everything available (and not conflicting with their simple limits model)" setting, because the app dev was too lazy to tie things down.
If you want a glance at that, install SELinux in non-enforcing mode and look at the log. You'll be surprised what kinds of system calls and file accesses your simple applications make that they don't really need. Much of that is just routine init stuff from some library they use, and most fails silently and with no trouble if they can't get that port or file lock they request, but still...
Parent
very sceptical (Score:5, Insightful)
So anyone coming up with a "new and improved" security concept is selling an untested solution. Because security is always tested in the field, never (at least never properly) in the lab.
And yes, Unix permissions are primitive. But they work, they are reliable and we know their shortcomings and limitations.
Re:very sceptical (Score:5, Insightful)
True, but inapplicable in this case. For two reasons.
How can we have a new security model, but no new security model concepts? What's new is that ideas which have been reserved for high-security systems are being applied to a system that large numbers of people will actually use.
The core ideas are:
The only innovation here is in the decision to apply these known security models/tools to all applications on the OLPC. There is some good thought that has gone into determining what kinds of restrictions can be placed on apps, and the bit about constraining the permissions that apps can request during installation (e.g. either network or file access, not both -- without digital signature or explicit user authorization) is clever, but there's nothing fundamentally new.
But the issue is somewhat deeper than that, as well.
It's important to realize that the traditional security model does not work for OLPC machines. Why? Because (1) they're specifically designed as computers whose software is highly mutable and (2) they're specifically designed to live as part of a network. The traditional model works great if you can thoroughly prove the integrity of the software on the system and then lock it down -- but you can't do that on machines that are constantly connected to others and always exchanging bits of code and data.
You can try, of course. And we do. And we've seen just how well it works. Massive botnets of zombies is the result as is high-powered machines dedicating a significant portion of their processing power to defending themselves against malicious code -- and failing.
The traditional model is fundamentally broken in the networked age, and the OLPC machines are not only networked, but designed to facilitate every user becoming an at least minimally-competent programmer and to encourage widespread, free sharing of user-developed code.
New problems require new solutions. In this case, it appears that we already had all of the tools required available, they just weren't widely used.
My prediction: The XO security model will be an outstanding success story. It'll have its problems, and it'll have to be tweaked in various ways, but the basic ideas are so good, and so fundamentally simple, that it will work very well. Application authors will be able to achieve what they want, and security will be generally quite good.
I also think that the OLPC project is one of the most amazing stories in the history of computing. It's giving a bunch of brilliant people the opportunity to completely re-imagine computing, and they're doing it with a laser focus on the needs of the people who use the computers, rather than the needs of those who sell the computers and the software.
Parent
The one major difference to MS "trusted" computing (Score:5, Insightful)
systems may impose various prohibitions on the user's actions, there
must exist a way for these security systems to be disabled. When that is
the case, the machine will grant the user complete control."
That is the one of the key differences between Bitfrost and Microsoft
"trusted computing" schemes: you as owner of the box can get around it.
A Stink-Rose by any other name... (Score:3, Interesting)
"Beyond cyberthreats, the XO laptop will have an anti-theft system designed to render stolen laptops useless. Each XO is assigned a "lease," secured by cryptography, that allows it to operate for a limited period of time. The laptop connects to the internet daily and checks in with a country-specific server to see if it's been reported stolen. If not, the lease is extended another few weeks."
Congratulations, you have destroyed this projects credibility, desirability and much of the good will that the open source community was providing.
I wonder this would rule out any interaction with the GPL v3?
Re: (Score:3, Insightful)
So, it's not enabled by default. I'm not a huge fan of this system, but higher up in the spec where it's described, it appears to be implemented entirely in software (it's a *deterrent*, not intended to make it com
It's not hard to do this. Just not compatible. (Score:5, Insightful)
It's not hard to do this. Several groups had systems this tight working back in the 1980s. For that matter, Multics had it right in the late 1960s. Linux has it now, in NSA SELinux.
It breaks existing applications, of course. The OLPC people have a huge advantage - they don't care about existing applications. They can say to application developers, "these are the security constraints - design to them." That's a huge win.
Somebody should have done this by now for phones and palmtops, but, unfortunately, those things started out so underpowered they barely had an operating system. So they have their own legacy problems.
Re:It's not hard to do this. Just not compatible. (Score:4, Informative)
Parent
Re:It's not hard to do this. Just not compatible. (Score:4, Informative)
First, the two concepts "virtual machine" and "mandatory access control" are orthogonal. A virtual machine may choose to implement MAC (and the sandbox that Java applets are placed in is a MAC implementation), or it may choose any other security model (or none).
Mandatory Access Control is simply a set of permissions that are independent of the identity of the user who owns a process. Unix and Windows permissions are all about the process UID, every decision about what the process should or should not be allowed to do comes down to a check of user-related information.
With MAC, the permissions are associated instead with the process and/or the data it's acting on. MAC as implemented by SELinux (and the XO security model, BTW) associates a set of permissions with each program. Program A is configured as being allowed to do X or Y but not Z, while program B is allowed to do Y or Z but not X.
Note that these permissions are orthogonal to UID-based permissions. Suppose a program has permission to read files from a given region of the file system, but the user account the program is running as does not have permission to read a given file within that region. The program can't read that file while running as that user.
Second, there's nothing in the Bifrost spec about virtual machines. It's not clear, but it looks to me like the Bifrost MAC is implemented at the OS layer, in spite of the fact that the Wired article talks about VMs.
No, it is most definitely not role-based -- role-based access is again based on user ID (via the roles associated with that UID at the moment). Actually, I think there are probably traditional user and group-based permissions as well, but the key security tools defined by Bifrost are MAC, not RBAC.
Parent
Re: (Score:3, Insightful)
Hence my difficulty in classifying the type of access control. I don't know enough about the Java sandbox to say whether it is MAC or not, but I doubt it. MAC entails assigning a specific classification to each object, and clearances to subjects
Two Cents (Score:4, Insightful)
I've got two things to say.
1. Bring these security additions to public linux distributions.
2. Would you (and the rest of
"What's deeply troubling..." (Score:3, Insightful)
Oh, my! I feel so... so... exposed!
So let's make the default umask "077" for all UNIX- and Linux-based systems. Would that help? To a great extent. Would it decrease usability? Sure. But if that 'swhat it takes to have some semblance of system security, so be it. It seems that work on file-level security has taken steps backwards since the "do everything via a browser" mentality began taking root in UNIX/Linux. That us brings automatic execution of programs based on some file's extension (the so-called "helper" applications). Yep, that proved to be such a winner in the DOS/Windows arena that we should all start doing it. What little cool feature of the web that makes something easier to do hasn't proven to have gaping security holes in it? Every so-called "advance" in usability seems to have a detrimental effect on system security. Always has and, I'd bet, always will. Usabililty and security are playing a zero-sum game. You can't seem to have more of one without less of the other. But I digress...
I don't know what the ultimate solution will be but I'm thinking that liberal use of "umask 077", RBAC (especially on root) and ACLs, and a default policy of "drop" on one's firewalls will go a long way in protecting system(s). All of those have been available on UNIX/Linux for quite a while. So much for permission bits being "virtually the only real control mechanism that a user has over her personal documents today".
The creator of this "BitFrost" cryptographic security scheme says:
Frankly, I kept having the same feeling as I read the Wired article. I think what it was that he was missing was "simplicity". Dongles for laptops in rural villages? Local license servers for villages that have no internet access? Jeebus!
There are things in the spec I object to... (Score:3, Insightful)
Seriously, I agree with most their findings and strategies to mitigate the risks of theft, lost privacy, etc. I also find it noteworthy that the Mic and Cam both have a direct wired LED to indicate activation of said components, where the LED can not be turned on/off by software at all. Thus eavesdropping becomes evident. The spec is a nice read and most points Ivan makes are (from my standpoint) well thought through and sensible for the environment in which the XO is to be deployed.
What I object against though, is point 8.12 (P_X) [laptop.org] of the spec. As I understand it, as long as you happen to be in possession of a "trusted" key to the machine (which will certainly be OLPC and the government of the child in posession of the XO) you may eavesdrop on any resource of the X window system as you see fit? Correct me if I am wrong, but AFAIK the X protocol was never designed with security in mind. So sending commands to another program might also impicitly mean the ability to check the state of that program.
Would any X expert please confirm or dismiss this, as I can't becase I'm no X expert myself.
Who holds the keys? (Score:3, Interesting)
The people who hold these keys are plenty vulnerable to corruption, intimidation and good old-fashioned trickery. This doesn't invalidate the security model, but I'd be interested to know how they mean to preserve the integrity of the keychain in case of theft, misuse, disaster, going-out-of-business and aliens.
L
jail is a hack (Score:3, Informative)
RFCNAMEG If set, the new process starts with a clean name space. A new name space must be built from a mount of an open file descriptor.
Linux did clone the Plan 9 feature though (Score:5, Insightful)
When you want a new namespace, you specify the CLONE_NEWNS flag. (root only, sorry, because of setuid concerns)
Once you have a new namespace, you can unmount things you don't need. You can do bind mounts, which let you graft directories onto other places. You can use a bind mount to make a read-only copy of something, then unmount the original... all without mucking up processes that aren't part of the same CLONE_NEWNS group. Portions of the filesystem tree can be shared as well, in case you really do want changes to appear to both sides of the CLONE_NEWNS. Access to things can be permanently given up within the CLONE_NEWNS group, making for a rather fine jail that generally beats jail(8) quite severely.
There are extra goodies for stuff like isolating the view of system time, the view of executing processes, etc.
Parent
Re:$5000 laptop? Pulleeze!! (Score:5, Informative)
Hardcore geek != executive.
You've obviously never met an executive, they don't have the slightest problem splashing out (from the company account) well upwards of $5000. They think they're worth it.
Parent
Re:chmod, chown, etc.? (Score:5, Insightful)
Well, Windows uses the ACL system of permissions it stole from VMS. It actually does provide more control (that you don't need 99.9% of the time), such as multiple groups having different levels of permissions.
Increasingly complex file-level security does come with one major drawback, however... I can look at a file under Linux and instantly tell (possibly with a quick check of the members of a single group) who has what access to it. Under Windows, good luck with that. XP actually has an advanced security tab, "Effective Permissions", solely for the purpose of testing what access a given user has to a file or directory. Short of that tool, some of the more complex possible configurations (which don't take any sort of unrealistically contrived setups to get, such as a combination of local and domain groups having both inherited and locally set permissions) would leave you feeling very uncomfortable guessing who has access to a given file. And of course, that tab only lets you check one user or group at a time, so it proves utterly useless in answering the simple question "Who can overwrite this file".
In fairness, you could write a script to test every user and group against a given set of files and directories and generate a report off the output, but seriously, would anyone really consider that "better" than "0750, yup, that looks good"?
Parent
Windows ACL permissions are nice (Score:3, Insightful)
Still, the fact that Unix permissions are still around, being used and adequate for most people is a testament to the c
uh, FYI, Linux DOES have ACLs now (Score:3, Interesting)
The ACLs are usually almost like the ones Windows uses, with a few minor differences:
a. UNIX-like systems normally still use rwx.
b. Windows normally disables checking permissions on parent directories.
c. Windows does a funny sort of inheritance thing that kills performance. (thus the above speed hack)
The stuff OLPC is using is way more powerful though. An ACL on your own data file will not protect your data from being damaged by a trojan. The OLPC project use
Re: (Score:3, Informative)
You do realize Microsoft hired Dave Cutler (the guy who created VMS) to design NT, right? I wouldn't say they stole VMS, Cutler simply applied his knowledge of ACL security to Windows NT security.
"Increasingly complex file-level security does come with one major drawback, however... I can look at a
Re:chmod, chown, etc.? (Score:4, Insightful)
Too right it was difficult. My WinXP installation decided that a "security" tab was just too confusing so it didn't display it. There was some arcane ritual I needed to perform to enable it. The help files mostly just assumed this ritual had been performed, so they said "click on the security tab and then...", flatly contradicting what I could see (a Properties window with no security tab). There was a lot of frustration before I stumbled on the ritual.
Parent
Re: (Score:3, Interesting)
Yes, actually, I do. And I'd say most of the same complaints about VMS - Except that Windows doesn't have the rock-solid stability to make up for the hellishness of use.
Yeah, because right-clicking a file or folder, selecting Properties, then choosing the confusingly labeled Security tab is difficult.
Hypothetical situation for you...
You have Domain Admin (but not EA) on a standard mid-sized multi-site corpo
Re: (Score:3, Informative)
This is not entirely true: A file chmod'd 777 appears to be readable and writeable by everyone, but if it's contained within a directory chmod'd 700, then it is accessible to only the owner (unless a user has an open handle to that directory already, but let's not split hairs). Ditto if the parent directory is 777, but *that* directory's parent is 700.
The same is going
Re: (Score:3, Interesting)
Re:chmod, chown, etc.? (Score:4, Interesting)
I think the traditional UNIX model is too simple to call bolting on an List of names and permissions used for Access Control (in place of the user/group/mask approach) a "trivial tweak".
Parent
It isn't about ACLs. (Score:5, Interesting)
It's the sandboxing. A program run by a given user doesn't automatically get the user's full permissions -- it only gets a small subset. For example, it can't open files from the user's home directory other than by calling a trusted system File Open dialog, which allows the user to select the file and returns an open file handle to the application (or in OLPC's case hardlinks the file into the chroot jail).
In terms of research projects, see the secure scripting language E [erights.org] and the proof of concept CapDesk [combex.com].
Interestingly, in the commercial world it only seems to turn up in safe bytecode runtimes -- there's very little out there for native code. For an example of something similar in concept look at JNLP [sun.com] or ClickOnce [microsoft.com] deployers.
Parent
Re: (Score:3, Insightful)
Re: (Score:3, Informative)
I just did, it contains this line:
o Exactly one user entry specified for the file
owner.
You have have the owner be a group, which would allow multiple users to technically be the owner, but this is not the same thi
Re:One Desktop per Village would be a better start (Score:5, Insightful)
Parent
Re:One Desktop per Village would be a better start (Score:4, Insightful)
Parent
Origin/rationale for name (Score:5, Interesting)
Parent
Re: (Score:3, Insightful)
128 MB RAM and 512 MB total storage in Flash RAM.
Of course all the apps are specifically rewritten for OLPC. Security aside, most applications written for today's computers with 100+GB HD's won't load on a computer with only 128 MB of RAM without VM. Heck, with swap-files/VM disabled, you can't boot into a typical install of XP if you only have 128MB RAM much less run any ap