mirror of
https://github.com/NixOS/nixpkgs.git
synced 2024-11-01 23:22:37 +00:00
cef2814a4f
This module adds an option `security.hideProcessInformation` that, when enabled, restricts access to process information such as command-line arguments to the process owner. The module adds a static group "proc" whose members are exempt from process information hiding. Ideally, this feature would be implemented by simply adding the appropriate mount options to `fileSystems."/proc".fsOptions`, but this was found to not work in vmtests. To ensure that process information hiding is enforced, we use a systemd service unit that remounts `/proc` after `systemd-remount-fs.service` has completed. To verify the correctness of the feature, simple tests were added to nixos/tests/misc: the test ensures that unprivileged users cannot see process information owned by another user, while members of "proc" CAN. Thanks to @abbradar for feedback and suggestions.
43 lines
1.5 KiB
Nix
43 lines
1.5 KiB
Nix
{ config, pkgs, lib, ... }:
|
|
with lib;
|
|
|
|
{
|
|
options = {
|
|
security.hideProcessInformation = mkEnableOption "" // { description = ''
|
|
Restrict access to process information to the owning user. Enabling
|
|
this option implies, among other things, that command-line arguments
|
|
remain private. This option is recommended for most systems, unless
|
|
there's a legitimate reason for allowing unprivileged users to inspect
|
|
the process information of other users.
|
|
|
|
Members of the group "proc" are exempt from process information hiding.
|
|
To allow a service to run without process information hiding, add "proc"
|
|
to its supplementary groups via
|
|
<option>systemd.services.<name?>.serviceConfig.SupplementaryGroups</option>.
|
|
''; };
|
|
};
|
|
|
|
config = mkIf config.security.hideProcessInformation {
|
|
users.groups.proc.gid = config.ids.gids.proc;
|
|
|
|
systemd.services.hidepid = {
|
|
wantedBy = [ "local-fs.target" ];
|
|
after = [ "systemd-remount-fs.service" ];
|
|
before = [ "local-fs-pre.target" "local-fs.target" "shutdown.target" ];
|
|
wants = [ "local-fs-pre.target" ];
|
|
|
|
serviceConfig = {
|
|
Type = "oneshot";
|
|
RemainAfterExit = true;
|
|
ExecStart = ''${pkgs.utillinux}/bin/mount -o remount,hidepid=2,gid=${toString config.ids.gids.proc} /proc'';
|
|
ExecStop = ''${pkgs.utillinux}/bin/mount -o remount,hidepid=0,gid=0 /proc'';
|
|
};
|
|
|
|
unitConfig = {
|
|
DefaultDependencies = false;
|
|
Conflicts = "shutdown.target";
|
|
};
|
|
};
|
|
};
|
|
}
|