stockholm/krebs/3modules/shadow.nix
2021-11-08 05:14:49 +01:00

82 lines
2.1 KiB
Nix
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

with import <stockholm/lib>;
{ config, pkgs, ... }: let
cfg = config.krebs.shadow;
mergeShadowsJq = pkgs.writeJq "merge-shadows.jq" ''
def is_int: . == (. | floor);
def fields_4_to_9: ["", "", "", "", "", ""];
def check_fields_3_to_9: (.[2] | tonumber | is_int) and .[3:] == fields_4_to_9;
def read_value:
split(":") |
if length == 9 then
if check_fields_3_to_9 then
.
else
error("unrecognized field contents")
end
elif length == 2 then
if .[1] | test("^\\$6\\$") then
. + ["1"] + fields_4_to_9
else
error("unrecognized hashed password")
end
else
error("unexpected field count: expected 9 or 2, got \(length)")
end;
def write_value:
join(":");
split("\n") |
map(select(length > 0) | read_value) |
reverse |
unique_by(.[0]) |
map(write_value) |
sort |
join("\n")
'';
in {
options.krebs.shadow = {
enable = mkEnableOption "krebs.shadow" // {
default = cfg.overridesFile != null;
};
overridesFile = mkOption {
apply = x: if typeOf x == "path" then toString x else x;
default = null;
description = ''
Path to a file containing additional shadow entries, used for adding
encrypted passwords which should not be placed into the Nix store.
The overrides file may contain either regular shadow(5) entries like:
<code>login-name:hashed-password:1::::::</code>
Or shortened entries only containing login name and password like:
<code>login-name:hashed-password</code>
'';
type = types.nullOr (types.either types.path types.absolute-pathname);
};
};
config = let
in mkIf cfg.enable {
system.activationScripts.users-tv = stringAfter [ "users" ] /* sh */ ''
(
set -efu
umask 77
${pkgs.jq}/bin/jq -Rrs -f ${mergeShadowsJq} \
/etc/shadow ${cfg.overridesFile} > /etc/shadow~
${pkgs.coreutils}/bin/mv /etc/shadow /etc/shadow-
${pkgs.coreutils}/bin/mv /etc/shadow~ /etc/shadow
)
'';
};
}