commit 49a60b722eb4a7b12f3d1e4945d0728d9b60aebd · pyrox.dev/nixpkgs

nixos/modules/module-list.nix

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         ./programs/nano.nix

     

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         ./programs/nautilus-open-any-terminal.nix

     

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         ./programs/nbd.nix

     

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         ./programs/nekoray.nix

     

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         ./programs/neovim.nix

     

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         ./programs/nethoscope.nix

     

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         ./programs/nexttrace.nix

+90

nixos/modules/programs/nekoray.nix

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       {

     

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         config,

     

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         pkgs,

     

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         lib,

     

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         ...

     

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       }:

     

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       let

     

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         cfg = config.programs.nekoray;

     

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       in

     

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       {

     

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         options = {

     

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           programs.nekoray = {

     

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             enable = lib.mkEnableOption "nekoray, a GUI proxy configuration manager";

     

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             package = lib.mkPackageOption pkgs "nekoray" { };

     

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             tunMode = {

     

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               enable = lib.mkEnableOption "TUN mode of nekoray";

     

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               setuid = lib.mkEnableOption ''

     

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                 setting suid bit for nekobox_core to run as root, which is less

     

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                 secure than default setcap method but closer to upstream assumptions.

     

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                 Enable this if you find the default setcap method configured in

     

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                 this module doesn't work for you

     

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               '';

     

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             };

     

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           };

     

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         };

     

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         config = lib.mkIf cfg.enable {

     

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           environment.systemPackages = [ cfg.package ];

     

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           security.wrappers.nekobox_core = lib.mkIf cfg.tunMode.enable {

     

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             source = "${cfg.package}/share/nekoray/nekobox_core";

     

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             owner = "root";

     

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             group = "root";

     

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             setuid = lib.mkIf cfg.tunMode.setuid true;

     

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             # Taken from https://github.com/SagerNet/sing-box/blob/dev-next/release/config/sing-box.service

     

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             capabilities = lib.mkIf (

     

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               !cfg.tunMode.setuid

     

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             ) "cap_net_admin,cap_net_raw,cap_net_bind_service,cap_sys_ptrace,cap_dac_read_search+ep";

     

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           };

     

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           # avoid resolvectl password prompt popping up three times

     

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           # https://github.com/SagerNet/sing-tun/blob/0686f8c4f210f4e7039c352d42d762252f9d9cf5/tun_linux.go#L1062

     

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           # We use a hack here to determine whether the requested process is nekobox_core

     

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           # Detect whether its capabilities contain at least `net_admin` and `net_raw`.

     

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           # This does not reduce security, as we can already bypass `resolved` with them.

     

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           # Alternatives to consider:

     

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           # 1. Use suid to execute as a specific user, and check username with polkit.

     

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           #    However, NixOS module doesn't let us to set setuid and capabilities at the

     

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           #    same time, and it's tricky to make both work together because of some security

     

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           #    considerations in the kernel.

     

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           # 2. Check cmdline to get executable path. This is insecure because the process can

     

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           #    change its own cmdline. `/proc/<pid>/exe` is reliable but kernel forbids

     

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           #    checking that entry of process from different users, and polkit runs `spawn`

     

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           #    as an unprivileged user.

     

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           # 3. Put nekobox_core into a systemd service, and let polkit check service name.

     

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           #    This is the most secure and convenient way but requires heavy modification

     

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           #    to nekoray source code. Would be good to let upstream support that eventually.

     

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           security.polkit.extraConfig =

     

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             lib.mkIf (cfg.tunMode.enable && (!cfg.tunMode.setuid) && config.services.resolved.enable)

     

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               ''

     

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                 polkit.addRule(function(action, subject) {

     

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                   const allowedActionIds = [

     

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                     "org.freedesktop.resolve1.set-domains",

     

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                     "org.freedesktop.resolve1.set-default-route",

     

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                     "org.freedesktop.resolve1.set-dns-servers"

     

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                   ];

     

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                   if (allowedActionIds.indexOf(action.id) !== -1) {

     

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                     try {

     

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                       var parentPid = polkit.spawn(["${lib.getExe' pkgs.procps "ps"}", "-o", "ppid=", subject.pid]).trim();

     

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                       var parentCap = polkit.spawn(["${lib.getExe' pkgs.libcap "getpcaps"}", parentPid]).trim();

     

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                       if (parentCap.includes("cap_net_admin") && parentCap.includes("cap_net_raw")) {

     

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                         return polkit.Result.YES;

     

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                       } else {

     

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                         return polkit.Result.NOT_HANDLED;

     

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                       }

     

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                     } catch (e) {

     

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                       return polkit.Result.NOT_HANDLED;

     

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                     }

     

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                   }

     

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                 })

     

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               '';

     

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         };

     

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         meta.maintainers = with lib.maintainers; [ aleksana ];

     

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       }