curl https://some-url/ | sh

I see this all over the place nowadays, even in communities that, I would think, should be security conscious. How is that safe? What’s stopping the downloaded script from wiping my home directory? If you use this, how can you feel comfortable?

I understand that we have the same problems with the installed application, even if it was downloaded and installed manually. But I feel the bar for making a mistake in a shell script is much lower than in whatever language the main application is written. Don’t we have something better than “sh” for this? Something with less power to do harm?

  • rah@feddit.ukEnglish
    32·
    1 day ago

    You have the option of piping it into a file instead, inspecting that file for yourself and then running it, or running it in some sandboxed environment.

    That’s not what projects recommend though. Many recommend piping the output of an HTTP transfer over the public Internet directly into a shell interpreter. Even just

    curl https://... > install.sh; sh install.sh

    would be one step up. The absolute minimum recommendation IMHO should be

    curl https://... > install.sh; less install.sh; sh install.sh

    but this is still problematic.

    Ultimately, installing software is a labourious process which requires care, attention and the informed use of GPG. It shouldn’t be simplified for convenience.

    Also, FYI, the word “option” implies that I’m somehow restricted to a limited set of options in how I can use my GNU/Linux computer which is not the case.

    • gaylord_fartmaster@lemmy.world
      51·
      19 hours ago

      Showing people that are running curl piped to bash the script they are about to run doesn’t really accomplish anything. If they can read bash and want to review the script then they can by just opening the URL, and the people that aren’t doing that don’t care what’s in the script, so why waste their time with it?

      Do you think most users installing software from the AUR are actually reading the pkgbuilds? I’d guess it’s a pretty small percentage that do.

      • rah@feddit.ukEnglish
        11·
        4 hours ago

        Showing people that are running curl piped to bash the script they are about to run doesn’t really accomplish anything. If they can read bash and want to review the script then they can by just opening the URL

        What it accomplishes is providing the instructions (i.e. an easily copy-and-pastable terminal command) for people to do exactly that.

        • gaylord_fartmaster@lemmy.world
          2·
          4 hours ago

          If you can’t review a bash script before running it without having an unnecessarily complex one-liner provided to you to do so, then it doesn’t matter because you aren’t going to be able to adequately review a bash script anyway.

    • zygo_histo_morpheus@programming.dev
      23·
      1 day ago

      I mean if you think that it’s bad for linux culture because you’re teaching newbies the wrong lessons, fair enough.

      My point is that most people can parse that they’re essentially asking you to run some commands at a url, and if you have even a fairly basic grasp of linux it’s easy to do that in whatever way you want. I don’t know if I personally would be any happier if people took the time to lecture me on safety habits, because I can interpret the command for myself. curl https://some-url/ | sh is terse and to the point, and I know not to take it completely literally.

      • rah@feddit.ukEnglish
        41·
        1 day ago

        linux culture

        snigger

        you’re teaching newbies the wrong lessons

        The problem is not that it’s teaching bad lessons, it’s that it’s actually doing bad things.

        most people can parse that they’re essentially asking you to run some commands at a url

        I know not to take it completely literally

        Then it needn’t be written literally.

        I think you’re giving the authors of such installation instructions too much credit. I think they intend people to take it literally. I think this because I’ve argued with many of them.