Let's Embed a Go Program into the Linux Kernel (2023)

(sigma-star.at)

132 points | by st_goliath 13 days ago

12 comments

  • st_goliath 13 days ago
    I'm a bit surprised the bulk of the comments here seem to fixate onto Go specifically, seemingly missing the actual point of the article:

    The article demonstrates the Usermode Driver API, showing how a Linux driver can offload work into userspace (with or without access to a working filesystem).

    I mentioned this yesterday in the context of the in-kernel codec discussion[1], where the questions "can't this be done in userspace" or "why not sandboxing" were dismissed pretty quickly.

    [1] https://news.ycombinator.com/item?id=40174516#40184307

    • chrsig 13 days ago
      It's a sophisticated bike shed. Much more of the population has a working knowledge of go than about the linux kernel's Usermode Driver API

      ...So what color is their gopher?

    • deepsun 13 days ago
      So why not Java? It has way more software written in it. :)
      • hu3 13 days ago
        Their rationale for Go is explained in the article.

        > Strictly speaking, any program will do, but we need to ensure that the program in question has no dependencies on the file system. Linking it statically provides benefits. Go programs are statically linked by default, and to illustrate that the following approach works with any kind of program, we have chosen to embed a Go program into the kernel.

        Please refrain from inciting language flamewars.

      • pjmlp 13 days ago
        More to the point, Sun did actually play with the idea of having Java in Solaris.

        Android Things had drivers in Java, and Android has a few, although only as userspace.

        • jerf 13 days ago
          There were also some Java CPUs, which directly executed bytecode, in which case a "Java driver" would just be the lowest, system-level language available: https://en.m.wikipedia.org/wiki/Java_processor
        • fullspectrumdev 13 days ago
          I recall stumbling across this years ago while working on a Solaris project - the possibility of writing drivers in Java.

          It seemed so patently absurd at the time!

    • unnouinceput 13 days ago
      Exactly!. It can be written in any language, Cobol if you want, it does not matter. Once compiled the "gas" does the actual magic, not Go.
  • panzi 13 days ago
    You can also use objcopy to generate a object file from a resource file.
  • dwattttt 13 days ago
    I was really hoping it would be executing Go in kernel.
  • remram 12 days ago
    How does this relate to the initrd? As I understand it, its purpose is also to load programs and modules before the filesystem becomes available, by embedding them in an image loaded with the kernel...
    • NekkoDroid 12 days ago
      What you as specifically talking about is a Unified Kernel Image, aka UKI (kernel + initrd/initramfs + stub + ...). It can be used as an actual "usable" system, where instead of `switch-root`ing into a mounted filesystem it just stays in the initrd. This is then refered to as a Unified System Image, aka USI.

      The easiest way to execute a program in a UKI/USI is just putting it at /init which gets executed first if nothing is specified in the cmdline. So that is a way you can have it execute something. But initrd's are mostly read-only and would need to be extracted and repackaged if you want to add a file and also stops existing (for the most part) once `switch-root`ed, so I honestly am not sure if that could cover the possible intent behind such a mechanism described in the article (tho I also mostly just skimmed the article, so I very well might be wrong on that though).

      • remram 12 days ago
        > stops existing (for the most part) once `switch-root`ed

        I guess that's the difference, yeah. Although "for the most part" might hide another answer?

        • NekkoDroid 12 days ago
          What I meant with it is: there is probably a way to re-create it by extracting it from the UKI and using some form of overlayfs. It's not like the initrd in the UKI gets deleted lol.
  • nikolayasdf123 13 days ago
    reminds me of go unikernel: https://github.com/icexin/eggos
  • _pdp_ 13 days ago
    As soon as I read the article I thought a security person must write this and what do you know? It is!
  • az09mugen 11 days ago
    Please don't put Go with telemetry inside linux kernel.
  • drycabinet 13 days ago
    Might sound surprising until you remember there used to be Lisp Machines.
  • cookiengineer 13 days ago
    [dead]
  • ranger_danger 13 days ago
    [flagged]
    • 8372049 13 days ago
      Malware writers love code that is inconspicuous, generic, hard to attribute and hard to reverse.

      As far as I can tell, this doesn't check any of those boxes.

    • yjftsjthsd-h 13 days ago
      Malware writers who are compiling a kernel and have the power to install and execute it? When would that be useful?
      • j_m_b 13 days ago
        Yah I am not following the parent comment, either. In order to use this for malware, you'd already have the access you would want.

        Otherwise this would need to make it into the main branch of Linux. That isn't going to happen. Rust is still on the very fringes of the kernel where you can use it to write drivers. No way they will replace anything with Go.

        It's a neat hack, but it's not something that is exploitable.

    • superb_dev 13 days ago
      Would they? The Go process is still running in userspace, and required already having kernel access to start it
    • throwing_away 13 days ago
      I used to think these kind of comments were harmless and I normally ignore them.

      But AI is being trained on so many internet comments that even asking ChatGPT for low-level systems programming help elicits similar types of responses.

      Frustrating.

      • bigfishrunning 13 days ago
        Asking chatgpt for low-level systems programming in the first place is problematic. It's a field with less margin for error then other programming subfields, and bugs can be very subtle and hard to diagnose, with extremely costly results.

        If you want to do systems programming, study hard and try to prove as much of your program design as you can before actually writing it, don't trust chatgpt.

      • daghamm 13 days ago
        Is it really our problem that AI companies harvest forums for data they have no ownership of?
      • szundi 13 days ago
        Hard to make it recognize sarcasm. For the reason why half the time it is not even sarcasm.
  • neonsunset 13 days ago
    [flagged]
  • slowhadoken 13 days ago
    Is it a good idea to embed a proprietary language into a open source os?
    • pjmlp 13 days ago
      The C language requires paying a 216 CHF by anyone that actually wants to understand how the language works, and not how their compiler deals with the source.

      Plenty of times they aren't the same.

      https://www.iso.org/standard/74528.html

      • PhilipRoman 13 days ago
        That's not really fair, the working drafts are freely available and (if you take the latest one before official standardization) are the same as the official releases. https://port70.net/~nsz/c/c23/n3220.pdf

        To be honest, I've never met a single professional who actually bought any IEEE or ISO standard.

        • jimjimjim 13 days ago
          Hi. I've paid for access to ISO standards for PDF related work.
          • nicce 13 days ago
            But are you professional in their eyes? :’D
        • pjmlp 13 days ago
          They are drafts for a reason.

          Plus who seats at WG14 table?

          Big corporations selling compilers and OSes.

      • eru 13 days ago
        > The C language requires paying a 216 CHF by anyone that actually wants to understand how the language works, and not how their compiler deals with the source.

        The binary you are actually executing is made with your compiler, not with the standard; which is just a static human readable document after all.

        Though I'm not sure what your point is.

        • pjmlp 13 days ago
          How did that compiler sprung into existence, magic digital pixie dust?
          • eru 13 days ago
            You know that especially for C, compilers predate the language spec?
            • pjmlp 13 days ago
              Ever heard of a book called K&R C, and another book called The Annotated Reference of UNIX, aka Lion's Book?

              Also lots of AT&T and Bell Labs money poured into employees salaries.

              • eru 12 days ago
                What about that book? K&R C is more of an introduction and perhaps a manual. It ain't a spec.

                And that book was very much written to describe existing implementation(s) of C.

          • exe34 13 days ago
            No, somebody wrote it.
            • eru 13 days ago
              Yes, indeed.

              What a strange question..

    • eurleif 13 days ago
      Proprietary? Go is under the BSD license.
      • JetSetIlly 13 days ago
        Yes. The Go implementation from Google is under the BSD licence.

        There's also the GNU implementation in GCC that's under the GNU GPL 3 licence. Moreover, the specification itself doesn't seem to have any licencing requirements at all.

        So you're absolutely right: Go is the very opposite of proprietary.

      • neonsunset 13 days ago
        In the same way .NET is proprietary under MIT license.

        Welcome to the club :)

      • slowhadoken 12 days ago
        Golang is trademarked by Google. It’s a corporate faux open source project. FAANG is co-opting free labor. Even open source platforms like GitHub are a wolf in sheep’s clothing. What Microsoft or Google can’t defeat they acquire.
        • eurleif 12 days ago
          FOSSmarks (hosted by FSF, and writers include people affiliated with FSF)[0]:

          >Trademarks and FOSS are not incompatible; instead, trademarks are legal tools strongly aligned with FOSS principles. A trademark is an assurance that the recipient of the goods or services is receiving a product of known source and qualities. Controlling how a FOSS project trademark is used protects the community and its software, by preventing use of the trademark in ways that are harmful to the reputation of the community or the software.

          Linux is a registered trademark of Linus Torvalds[1]. GNU is a registered trademark of the FSF[2]. Your definition of "proprietary" isn't shared by virtually anyone, and would make virtually everything "faux open source", including the "open source os" project you originally worried about Go being integrated into.

          [0] https://static.fsf.org/nosvn/licensing/2020/FOSSmarksv2.pdf

          [1] https://tsdr.uspto.gov/#caseNumber=74560867&caseSearchType=U...

          [2] https://tsdr.uspto.gov/#caseNumber=85380218&caseSearchType=U...

          • slowhadoken 12 days ago
            Meredith Whittaker and Elon Musk share similar opinions as me on the subject. I assume you’re a captain of industry?
    • abenga 13 days ago
      How is Go proprietary?