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CapROS: Capability-Based Reliable Operating System
- mikewarot 10mo agoWhy is it that every Capability based system seems to be a toolkit for running a single program instead of an OS ready for daily use? Is it just me?
- kragen 10mo agoIt's just you. seL4, CheriBSD, etc., do not fit your description. Neither did KeyKOS itself. You're presumably looking at research prototypes.
- ratmice 10mo agoI'd also note capros doesn't fit that description either. I don't know that there were examples that ran more than a single process. That's probably not true, for anything relying on drivers since user mode drivers are basically processes there... but in the way that people might think of a process.
- kragen 10mo agoI mean, there isn't exactly a thriving ecosystem of existing software built for CapROS. Right now I don't think anybody even has CapROS itself building. The problem has gotten a lot easier since the EROS days, thanks to Xen, QEMU, UEFI (?), and the explosion of cheap hardware, but it looks like maybe Charlie got sick or lost interest or something?
- ratmice 10mo agoYeah, I did see a email on a capabilities list from him about him no longer working on it because of lack of feedback & wanting to just enjoy his retirement. That was the impression I got. When he had resumed his work on it, I personally had been going through a back injury. I still feel bad that I didn't get a chance to contribute any of the hardware ports and software I wrote for it.
- kragen 10mo agoHmm, do you know when?
- ratmice 10mo agoI wasn't able to google it, or find a public link to the email (but it was posted on a public list) so here is some relevant snippets from it. Nov 20 2022 titled CapROS status "When I retired a year ago I hoped to correct some of those issues, but I want to enjoy retirement and not just have a full-time unpaid job.", ... "I am considering just abandoning CapROS. I believe there are some useful ideas in the system, but so far no one seems to have known or cared about them."
- ryukafalz 10mo agoSince it is a public list, here's the link: https://groups.google.com/g/cap-talk/c/Box4XXhSevw/m/18pUqAQnAQAJ https://groups.google.com/g/cap-talk/c/Box4XXhSevw/m/18pUqAQ... He posted on the list recently too if folks were worried: https://groups.google.com/g/cap-talk/c/XCBwf-zpJWA/m/6CWsNA-FAAAJ https://groups.google.com/g/cap-talk/c/XCBwf-zpJWA/m/6CWsNA-...
- spencerflem 10mo agoCheck out Genode Sculpt for a vision of a workable desktop ! It’s capable of dynamic flows, adding and removing programs, has ports of Chromium and Virtual Box. The devs daily drive it :)
- wmf 10mo agoA lot of OS projects develop the kernel then run out of steam. It's especially hard for capabilities because there's no established standard like Unix/Posix to copy. Capability OSes are still a research topic.
- naasking 10mo agoCapability-based operating systems are sufficiently dissimilar to standard ACL operating systems that ordinary software cannot be directly ported without losing some or many of the capability advantages. Furthermore, they are typically very security focused, and so they they've spent a lot of time researching security-focused interfaces and idioms for end users, rather than just re-implementing the hodge-podge of poorly thought out user interfaces that seem to reintroduce the same security vulnerabilities again and again, eg. CSRF is just the "confused deputy" attack known since the 1980s. I suggest reading some of their stuff [1], it's pretty interesting and accessible. [1] The EROS Trusted Window System, https://srl.cs.jhu.edu/pubs/SRL2003-05.pdf https://srl.cs.jhu.edu/pubs/SRL2003-05.pdf
- kragen 10mo agoSeems like Charlie hasn't been merging pull requests in three years: https://github.com/capros-os/capros https://github.com/capros-os/capros And the list has been idle since then: https://sourceforge.net/p/capros/mailman/capros-devel/ https://sourceforge.net/p/capros/mailman/capros-devel/ I wonder if something has happened to him? I hope he's okay.
- mfedderly 10mo agoI had the privilege of taking two classes with Dr Shapiro while I was in undergrad. The second class revolved around a related operating system named Coyotos. One of the most memorable classes was a 3 hour session where we worked through the boot sequence step by step [1]. The single lecture helped us all appreciate the delicate dance to bring up an x86 processor, a history lesson in the various features that had been bolted onto x86 over time, and a bunch of helpful debugging tips when your options are limited (it prints "Co" "yo" and "tos" in different stages!). This was easily one of my most memorable lectures from undergrad, and it really helped to show me that even your operating system is just more software that you can read and understand. 1. https://github.com/vsrinivas/coyotos/blob/c68719b851e253aa11321ce2cca1d0ddbdeeeaf6/src/sys/arch/i386/kernel/boot.S https://github.com/vsrinivas/coyotos/blob/c68719b851e253aa11...
- kragen 10mo agoCoyotos and CapROS are two continuations of EROS.
- ryanjshaw 10mo agoI was a nerdy kid living in the middle of nowhere in Africa. I think we’d had dialup for about 2 years at that, and I emailed him with some questions about how to understand the mathematical notations used in his EROS work. He was very kind and helpful in his response, even though my questions were probably very naive.
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- btilly 10mo agoThe fact that we went with access control lists instead of true capabilities has long been a disappointment to me. For people who understand OO, capabilities are the simplest model in the world. You hand out objects. You can call methods on the object. What that method call has access to depends on the permissions on the object, not your permissions. Entire classes of security mistakes (most notably the "confused deputy" become impossible. The only commercial success that was a true capability system was the AS/400. Not coincidently, single stand alone machines averaged 99.99%-99.999% uptime. And it never had a significant security compromise. (Individual systems did, of course, have problems due to weak passwords and poor configuration. But they were still remarkably resistant. Capability systems work so well that when people wanted to improve security on Linux, they called it capabilities. Even though it wasn't. Unfortunately, the world went with ACLs. That's baked in to the design of things like Windows and POSIX. Which means that all of the consumer software out there expects ACLs. In order to get them to run on a pure capability system, you have to do things like create a POSIX subsystem. At which point, you've just thrown away the whole reason to use capabilities in the first place.
- EGreg 10mo agoI guess you must really love Capnproto then: https://github.com/iguazio/go-capnproto2 https://github.com/iguazio/go-capnproto2
- btilly 10mo agoNot sure why you think that my opinions about operating systems would predict my opinions about an RPC system.
- kragen 10mo agoPossibly because Cap'n Proto includes a capability system that's currently widely deployed.
- ocdtrekkie 10mo agoYou may want to change this link, this is an extremely old fork of the Go capnp implementation. It's neither official nor current! I'd recommend just pointing to capnproto.org
- pyrolistical 10mo agohttps://en.wikipedia.org/wiki/Capability-based_security https://en.wikipedia.org/wiki/Capability-based_security It’s like sharing google doc link. You configure the link to be read only or read/write. Now imagine you can create as many links as you want with all possible permission combinations. Then you have a capability based system
- contrarian1234 10mo agoMost of my "wtf is going on" moments on Linux have to do with permissions. I loath the industry move to even more security. I want a more Emacs-like experience. Multiuser systems have become the exception and most people have a personal computer with one user. Dealing with evil apps is a loosing battle b/c the attack surface is too large. I think the counter argument to more security is Distro Repos. When was the last time you apt-get'ed some software and had your documents stolen? If you add blocks then you need to somehow communicate to the use when it's failing and that's hard... You see the shitshow that is Android security where apps have mysterious access to some directories and not others and it's impossible to understand what's going on. Maybe capabilities will work better, it's unclear to me.
- krautburglar 10mo agoAbsolutely! Most of it is there to protect their moats from us, not us from “hackers”.
- iberator 10mo agoJust link statically compiled emacs into /sbin/init and you are done
- iberator 10mo agoIntel did this is 1989 with iAPX 432. Super interesting and SUPER complex (just check out the documentation of cpu architecture), that's it failed hard. Flat memory model always win vs Star Trek like architecture who bo one understands
- gnufx 10mo ago1970s-ish capability systems with support in hardware/firmware include CAP, Flex, System/38, Plessey System 250 (which a former colleague worked on) -- the last two commercial; see https://en.wikipedia.org/wiki/Capability-based_security https://en.wikipedia.org/wiki/Capability-based_security. I'd like to think their time has come, given vulnerabilities I see.
- silasdavis 10mo agoMost of the links seem to be broken on https://www.capros.org/overview.html https://www.capros.org/overview.html
- retrac 10mo agoI've written a little bit before about KeyKOS/GNOSIS, which is the capability operating system used by Tymshare to host their timesharing language services on IBM mainframes, in the 70s and 80s. From a comment 3 years ago I'll just repost the relevant part: > KeyKOS (developed by Tymshare for their commercial computing services in the 1970s) - A capability operating system. If everything in UNIX was a file, then everything in KeyKOS was a memory page and capabilities (keys) to access those pages. The kernel has no state that isn't calculated from values in the virtual memory storage. The system snapshots the virtual memory state regularly. There are subtle consequences from this. Executing processes are effectively memory-mapped files that constantly rewrite themselves, with only the snapshots being written out. Snapshotting the virtual memory state of the system snapshots everything -- including the state of running processes. There's no need for a file system, just a means to map names to sets of pages, which is done by an ordinary process. After a crash, processes and their state are internally consistent, and continue running from their last snapshot. For those who are intrigued, there's a good introduction, written in 1979, by the system's designers available here: http://cap-lore.com/CapTheory/upenn/Gnosis/Gnosis.html http://cap-lore.com/CapTheory/upenn/Gnosis/Gnosis.html (It was GNOSIS before being renamed KeyKOS.) And a later document written in the 90s aimed at UNIX users making the case: http://cap-lore.com/CapTheory/upenn/NanoKernel/NanoKernel.ht http://cap-lore.com/CapTheory/upenn/NanoKernel/NanoKernel.ht... Some work on capability systems continues, but it seems the lessons learned have largely been forgotten. The core abstraction is simpler than the Unix process model or that of many other operating systems. Processes have keys which access virtual memory pages. All of storage including persistent secondary storage is just one big pool of virtual memory pages. These can be shared between processes. That's all that's necessary to implement things like filesystems and networking which are often thought to require special handling. A filesystem is just names and addresses of pages in storage. Give a process a capability to do shared memory with a process that maintains such a structure. I find the emphasis on minimizing process and kernel state, such that processes can be snapshot and frozen at any time and are inherently persistent, handled as the set of the relevant pages, to be genius. Though the architecture does have the classic microkernel/nanokernel performance penalties, as have been long debated.
- kragen 10mo agoDid they actually deploy GNOSIS at Tymshare? I hadn't heard that. I thought that the reason they spun out Key Logic was that Norm hadn't convinced Tymshare management to deploy GNOSIS. For example, in https://conservancy.umn.edu/server/api/core/bitstreams/a39e58bc-2e03-4a34-9a5e-7bd138835809/content https://conservancy.umn.edu/server/api/core/bitstreams/a39e5... p. 37, he says: > That was their [Derwent's] idea. I thought it was very clever and we realized that we couldn’t do it with our current software but that software like that could be written. And KeyKOS was the outcome of that. Tymshare and another company, Key Logic, did not succeed in making that commercial. It would’ve been a high security system with novel features. Later in the interview, he says Tymshare timesharing on the 370 (the IBM machine) started out on VM/CMS. If you have conflicting information, I'd love to see it!
- ahlCVA 10mo agoThere is also a relatively modern capability-based kernel in the L4 family of microkernels, called Fiasco.OC: https://os.inf.tu-dresden.de/fiasco/overview.html https://os.inf.tu-dresden.de/fiasco/overview.html There are also a bunch of components for building a functional userspace (such as L4Re or Genode).
- NooneAtAll3 10mo agowhat does L4 mean here?
- sirwhinesalot 10mo agoL4 was a microkernel design by Jochen Liedtke (RIP). It was notable for proving that microkernels can perform much better than was thought at the time (L4 performed 20x better than the Mach microkernel). The work was so influential it got the ACM SIGOPS Hall of Fame Award in 2015. A whole family of microkernels based on that original design have since been developed, hence the "L4 microkernel family".
- unwind 10mo agoIt's a family of microkernels. https://en.wikipedia.org/wiki/L4_microkernel_family https://en.wikipedia.org/wiki/L4_microkernel_family
- kragen 10mo agoLiedtke's fourth OS.
- Hexayurt 10mo agoWaterken was the same kind of logic, applied at web API scale. https://shiftleft.com/mirrors/www.hpl.hp.com/techreports/2010/HPL-2010-89.pdf https://shiftleft.com/mirrors/www.hpl.hp.com/techreports/201... The failure of this system and the HP ESpeak system are what left the gap which the blockchain smart contract model filled. I have complex thoughts about that.
- Hexayurt 10mo agoSpecifically: a globally visible distributed database is a fantastic resource for managing namespaces, as demonstrated by DNS and SSL Certificate Authorities. But when we start essentially doing _transactions_ by writing into such a database, it starts to look like buying a domain name every time you want to make a credit card payment. There is an architectural problem here.