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?

  • zygo_histo_morpheus@programming.dev
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    2 days 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. Ultimately though, if you are downloading software over the internet you have to place a certain amount of trust in the person your downloading the software from. Even if you’re absolutely sure that the download script doesn’t wipe your home directory, you’re going to have to run the program at some point and it could just as easily wipe your home directory at that point instead.

    • cschreib@programming.devOP
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      1 day ago

      Indeed, looking at the content of the script before running it is what I do if there is no alternative. But some of these scripts are awfully complex, and manually parsing the odd bash stuff is a pain, when all I want to know is : 1) what URL are you downloading stuff from? 2) where are you going to install the stuff?

      As for running the program, I would trust it more than a random deployment script. People usually place more emphasis on testing the former, not so much the latter.

    • rah@feddit.uk
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      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
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        23 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.uk
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          8 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
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            8 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.

            • rah@feddit.uk
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              3 hours ago

              If you can’t review a bash script before running it without having an unnecessarily complex one-liner provided to you

              Providing an easily copy-and-pastable one-liner does not imply that the reader could not themselves write such a one-liner.

              Having the capacity to write one’s own commands doesn’t imply that there is no value in having a command provided.

              unnecessarily complex

              LOL

              • gaylord_fartmaster@lemmy.world
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                2 hours ago

                I don’t think you realize that if your goal is to have a simple install method anyone can use, even redirecting the output to install.sh like in your examples is enough added complexity to make it not work in some cases. Again, those are not made for people that know bash.

      • zygo_histo_morpheus@programming.dev
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        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.uk
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          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.