nixos/update-users-groups: add support for account expiry

nixos/modules/config/update-users-groups.pl

@@ -4,6 +4,7 @@
 use File::Slurp;
 use Getopt::Long;
 use JSON;
+use DateTime;
 
 # Keep track of deleted uids and gids.
 my $uidMapFile = "/var/lib/nixos/uid-map";
@@ -22,6 +23,22 @@ sub updateFile {
     write_file($path, { atomic => 1, binmode => ':utf8', perms => $perms // 0644 }, $contents) or die;
 }
 
+# Converts an ISO date to number of days since 1970-01-01
+sub dateToDays {
+    my ($date) = @_;
+    my ($year, $month, $day) = split('-', $date, -3);
+    my $dt = DateTime->new(
+        year      => $year,
+        month     => $month,
+        day       => $day,
+        hour      => 0,
+        minute    => 0,
+        second    => 0,
+        time_zone => 'UTC',
+    );
+    return $dt->epoch / 86400;
+}
+
 sub nscdInvalidate {
     system("nscd", "--invalidate", $_[0]) unless $is_dry;
 }
@@ -283,22 +300,26 @@ sub parseUser {
 
 foreach my $line (-f "/etc/shadow" ? read_file("/etc/shadow", { binmode => ":utf8" }) : ()) {
     chomp $line;
-    my ($name, $hashedPassword, @rest) = split(':', $line, -9);
-    my $u = $usersOut{$name};;
+    # struct name copied from `man 3 shadow`
+    my ($sp_namp, $sp_pwdp, $sp_lstch, $sp_min, $sp_max, $sp_warn, $sp_inact, $sp_expire, $sp_flag) = split(':', $line, -9);
+    my $u = $usersOut{$sp_namp};;
     next if !defined $u;
-    $hashedPassword = "!" if !$spec->{mutableUsers};
-    $hashedPassword = $u->{hashedPassword} if defined $u->{hashedPassword} && !$spec->{mutableUsers}; # FIXME
-    chomp $hashedPassword;
-    push @shadowNew, join(":", $name, $hashedPassword, @rest) . "\n";
-    $shadowSeen{$name} = 1;
+    $sp_pwdp = "!" if !$spec->{mutableUsers};
+    $sp_pwdp = $u->{hashedPassword} if defined $u->{hashedPassword} && !$spec->{mutableUsers}; # FIXME
+    $sp_expire = dateToDays($u->{expires}) if defined $u->{expires};
+    chomp $sp_pwdp;
+    push @shadowNew, join(":", $sp_namp, $sp_pwdp, $sp_lstch, $sp_min, $sp_max, $sp_warn, $sp_inact, $sp_expire, $sp_flag) . "\n";
+    $shadowSeen{$sp_namp} = 1;
 }
 
 foreach my $u (values %usersOut) {
     next if defined $shadowSeen{$u->{name}};
     my $hashedPassword = "!";
     $hashedPassword = $u->{hashedPassword} if defined $u->{hashedPassword};
+    my $expires = "";
+    $expires = dateToDays($u->{expires}) if defined $u->{expires};
     # FIXME: set correct value for sp_lstchg.
-    push @shadowNew, join(":", $u->{name}, $hashedPassword, "1::::::") . "\n";
+    push @shadowNew, join(":", $u->{name}, $hashedPassword, "1::::", $expires, "") . "\n";
 }
 
 updateFile("/etc/shadow", \@shadowNew, 0640);

nixos/modules/config/users-groups.nix

@@ -308,6 +308,17 @@ let
         '';
       };
 
+      expires = mkOption {
+        type = types.nullOr (types.strMatching "[[:digit:]]{4}-[[:digit:]]{2}-[[:digit:]]{2}");
+        default = null;
+        description = lib.mdDoc ''
+          Set the date on which the user's account will no longer be
+          accessible. The date is expressed in the format YYYY-MM-DD, or null
+          to disable the expiry.
+          A user whose account is locked must contact the system
+          administrator before being able to use the system again.
+        '';
+      };
     };
 
     config = mkMerge
@@ -433,7 +444,7 @@ let
           name uid group description home homeMode createHome isSystemUser
           password passwordFile hashedPassword
           autoSubUidGidRange subUidRanges subGidRanges
-          initialPassword initialHashedPassword;
+          initialPassword initialHashedPassword expires;
         shell = utils.toShellPath u.shell;
       }) cfg.users;
     groups = attrValues cfg.groups;
@@ -587,7 +598,7 @@ in {
         install -m 0700 -d /root
         install -m 0755 -d /home
 
-        ${pkgs.perl.withPackages (p: [ p.FileSlurp p.JSON ])}/bin/perl \
+        ${pkgs.perl.withPackages (p: [ p.FileSlurp p.JSON p.DateTime ])}/bin/perl \
         -w ${./update-users-groups.pl} ${spec}
       '';
     };

nixos/tests/all-tests.nix

@@ -666,6 +666,7 @@ in {
   uptime-kuma = handleTest ./uptime-kuma.nix {};
   usbguard = handleTest ./usbguard.nix {};
   user-activation-scripts = handleTest ./user-activation-scripts.nix {};
+  user-expiry = runTest ./user-expiry.nix;
   user-home-mode = handleTest ./user-home-mode.nix {};
   uwsgi = handleTest ./uwsgi.nix {};
   v2ray = handleTest ./v2ray.nix {};

nixos/tests/user-expiry.nix

@@ -0,0 +1,70 @@
+let
+  alice = "alice";
+  bob = "bob";
+  eve = "eve";
+  passwd = "pass1";
+in
+{
+  name = "user-expiry";
+
+  nodes = {
+    machine = {
+      users.users = {
+        ${alice} = {
+          initialPassword = passwd;
+          isNormalUser = true;
+          expires = "1990-01-01";
+        };
+        ${bob} = {
+          initialPassword = passwd;
+          isNormalUser = true;
+          expires = "2990-01-01";
+        };
+        ${eve} = {
+          initialPassword = passwd;
+          isNormalUser = true;
+        };
+      };
+    };
+  };
+
+  testScript = ''
+    def switch_to_tty(tty_number):
+      machine.fail(f"pgrep -f 'agetty.*tty{tty_number}'")
+      machine.send_key(f"alt-f{tty_number}")
+      machine.wait_until_succeeds(f"[ $(fgconsole) = {tty_number} ]")
+      machine.wait_for_unit(f"getty@tty{tty_number}.service")
+      machine.wait_until_succeeds(f"pgrep -f 'agetty.*tty{tty_number}'")
+
+
+    machine.wait_for_unit("multi-user.target")
+    machine.wait_for_unit("getty@tty1.service")
+
+    with subtest("${alice} cannot login"):
+      machine.wait_until_tty_matches("1", "login: ")
+      machine.send_chars("${alice}\n")
+      machine.wait_until_tty_matches("1", "Password: ")
+      machine.send_chars("${passwd}\n")
+
+      machine.wait_until_succeeds("journalctl --grep='account ${alice} has expired \\(account expired\\)'")
+      machine.wait_until_tty_matches("1", "login: ")
+
+    with subtest("${bob} can login"):
+      switch_to_tty(2)
+      machine.wait_until_tty_matches("2", "login: ")
+      machine.send_chars("${bob}\n")
+      machine.wait_until_tty_matches("2", "Password: ")
+      machine.send_chars("${passwd}\n")
+
+      machine.wait_until_succeeds("pgrep -u ${bob} bash")
+
+    with subtest("${eve} can login"):
+      switch_to_tty(3)
+      machine.wait_until_tty_matches("3", "login: ")
+      machine.send_chars("${eve}\n")
+      machine.wait_until_tty_matches("3", "Password: ")
+      machine.send_chars("${passwd}\n")
+
+      machine.wait_until_succeeds("pgrep -u ${eve} bash")
+  '';
+}