I don’t like my ssh keys being stored in plain sight, I also don’t like having to type a passphrase to use them.

On windows, once you run ssh-add, the key is stored in a secure way and managed by some kind of session manager (source), at that point you can delete the key file and go about your life knowing that the key is safe and you won’t need to type a password again.

I would like something similar on linux, like storing the key via libsecret as you do with git, so that you can access your servers without having a key in plain text.

I think it’s possible to generate a key with a passphrase and have gnome-keyring or kwallet remember the passphrase, but it would be nicer to just securely store the key itself.

Can that be done?

  • @[email protected]
    12•6 months ago

    the threat model is exactly the same for those two scenarios, bear with it and focus on something else :)

  • IllecorsEnglish
    10•6 months ago

    Yes, it can be done. Not to the point of deleting your key (that makes no sense - you need the key), but ssh-agent is what you want. Add it to your shell config and it will only ask to be unlocked once per however often you define.

    I have this function defined and called:

    function ssh-agent-setup() {
    # SSH agent
    pid_file="$HOME/.ssh/ssh-agent.pid"
    SSH_AUTH_SOCK="$HOME/.ssh/ssh-agent.sock"
    if [ -z "$SSH_AGENT_PID" ]
    then
      # no PID exported, try to get it from pidfile
      SSH_AGENT_PID=$(cat "$pid_file")
    fi

    if ! kill -0 "$SSH_AGENT_PID" &> /dev/null
    then
      # the agent is not running, start it
      rm "$SSH_AUTH_SOCK" &> /dev/null
      >&2 echo "Starting SSH agent, since it's not running; this can take a moment"
      eval "$(ssh-agent -s -a "$SSH_AUTH_SOCK")"
      echo "$SSH_AGENT_PID" > "$pid_file"

      >&2 echo "Started ssh-agent with '$SSH_AUTH_SOCK'"
    fi
    export SSH_AGENT_PID
    export SSH_AUTH_SOCK
}

ssh-agent-setup

    This way it stores the unlocked key in memory until the end of the session.

    • @[email protected]OP
      6•6 months ago

      that makes no sense - you need the key

      But if it’s stored in a keyring or similar (like on windows) and the client reads from it you don’t need the file with the plain text key. Like you don’t store the git credentials in a file, but with libsecret.

      I would prefer something that never ask for the password.

      Things like the gnome-keyring or kwallet keep all the passwords in an encrypted file, they get decrypted and kept in ram using your login password when you log into gnome/KDE session and programs can ask for passwords using some API. Once you log out the passwords are removed from ram and no one can read them. My goal is to have something like this, so I’m never asked for a password, I just log into my session and everything is available

      • IllecorsEnglish
        3•6 months ago

        I don’t like what you’re trying to do, but I think gnome-keyring would do this for you. Seahorse is the gui for it

      • @damiumEnglish
        1•6 months ago

        I’n Windows it is not stored in a keyring but instead in the registry. This has basically the same security threat model as a local key file.

        The ssh-agent on Linux will do what you want with effectively the same security. The biggest difference being that it doesn’t run as a system service but instead runs in userspace which can make it easier to dump memory. There are some other agent services out there with additional security options but they don’t change the threat model much.

  • Goku
    -5•6 months ago

    Your ssh private keys are safe, assuming nobody has physical access to your home directory. You can configure them to not require a password.

    If someone has physical access to your computer then they could become compromised. If you are worried about that you could encrypt the whole drive.

    • Atemu
      14•6 months ago

      Unless some sandboxing or other explicit security measure is in place, any software you run typically has access to your entire home directory, including .ssh/. If any one of those was compromised somehow, they’ve got access to your SSH keys.

      That’s a gigantic attack surface if you ask me.

    • @[email protected]OP
      4•6 months ago

      It’s not a solution.

      Example: there’s another user with sudo access, he has access to my home folder, encrypting the drive doesn’t solve anything. Or maybe you just are not the system administrator.

      It’s not my usecase, but it’s definitely a reasonable situation.