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nixpkgs/nixos/modules/services/scheduling/atd.nix
Bjørn Forsman 497108b456 nixos/atd: remove "batch" from setuid wrappers
"batch" is a shell script so invoking it via setuid wrapper never worked
anyway. (The kernel drops perms on executables with shebang.) A previous
nixpkgs commit made "batch" invoke the NixOS setuid "at" wrapper to gain
needed privileges.

Thanks to @yesbox for noticing.
2017-10-16 19:08:19 +02:00

116 lines
2.7 KiB
Nix

{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.services.atd;
inherit (pkgs) at;
in
{
###### interface
options = {
services.atd.enable = mkOption {
type = types.bool;
default = false;
description = ''
Whether to enable the <command>at</command> daemon, a command scheduler.
'';
};
services.atd.allowEveryone = mkOption {
type = types.bool;
default = false;
description = ''
Whether to make <filename>/var/spool/at{jobs,spool}</filename>
writeable by everyone (and sticky). This is normally not
needed since the <command>at</command> commands are
setuid/setgid <literal>atd</literal>.
'';
};
};
###### implementation
config = mkIf cfg.enable {
# Not wrapping "batch" because it's a shell script (kernel drops perms
# anyway) and it's patched to invoke the "at" setuid wrapper.
security.wrappers = builtins.listToAttrs (
map (program: { name = "${program}"; value = {
source = "${at}/bin/${program}";
owner = "atd";
group = "atd";
setuid = true;
setgid = true;
};}) [ "at" "atq" "atrm" ]);
environment.systemPackages = [ at ];
security.pam.services.atd = {};
users.extraUsers = singleton
{ name = "atd";
uid = config.ids.uids.atd;
description = "atd user";
home = "/var/empty";
};
users.extraGroups = singleton
{ name = "atd";
gid = config.ids.gids.atd;
};
systemd.services.atd = {
description = "Job Execution Daemon (atd)";
after = [ "systemd-udev-settle.service" ];
wants = [ "systemd-udev-settle.service" ];
wantedBy = [ "multi-user.target" ];
path = [ at ];
preStart = ''
# Snippets taken and adapted from the original `install' rule of
# the makefile.
# We assume these values are those actually used in Nixpkgs for
# `at'.
spooldir=/var/spool/atspool
jobdir=/var/spool/atjobs
etcdir=/etc/at
for dir in "$spooldir" "$jobdir" "$etcdir"; do
if [ ! -d "$dir" ]; then
mkdir -p "$dir"
chown atd:atd "$dir"
fi
done
chmod 1770 "$spooldir" "$jobdir"
${if cfg.allowEveryone then ''chmod a+rwxt "$spooldir" "$jobdir" '' else ""}
if [ ! -f "$etcdir"/at.deny ]; then
touch "$etcdir"/at.deny
chown root:atd "$etcdir"/at.deny
chmod 640 "$etcdir"/at.deny
fi
if [ ! -f "$jobdir"/.SEQ ]; then
touch "$jobdir"/.SEQ
chown atd:atd "$jobdir"/.SEQ
chmod 600 "$jobdir"/.SEQ
fi
'';
script = "atd";
serviceConfig.Type = "forking";
};
};
}