nixpkgs/nixos/modules/config/ldap.nix

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{ config, lib, pkgs, ... }:
with pkgs;
with lib;
let
cfg = config.users.ldap;
# Careful: OpenLDAP seems to be very picky about the indentation of
# this file. Directives HAVE to start in the first column!
ldapConfig = {
target = "ldap.conf";
source = writeText "ldap.conf" ''
uri ${config.users.ldap.server}
base ${config.users.ldap.base}
timelimit ${toString config.users.ldap.timeLimit}
bind_timelimit ${toString config.users.ldap.bind.timeLimit}
bind_policy ${config.users.ldap.bind.policy}
${optionalString config.users.ldap.useTLS ''
ssl start_tls
tls_checkpeer no
''}
${optionalString (config.users.ldap.bind.distinguishedName != "") ''
binddn ${config.users.ldap.bind.distinguishedName}
''}
${optionalString (cfg.extraConfig != "") cfg.extraConfig }
'';
};
nslcdConfig = {
target = "nslcd.conf";
source = writeText "nslcd.conf" ''
uid nslcd
gid nslcd
uri ${cfg.server}
base ${cfg.base}
timelimit ${toString cfg.timeLimit}
bind_timelimit ${toString cfg.bind.timeLimit}
${optionalString (cfg.bind.distinguishedName != "")
"binddn ${cfg.bind.distinguishedName}" }
${optionalString (cfg.daemon.extraConfig != "") cfg.daemon.extraConfig }
'';
};
insertLdapPassword = !config.users.ldap.daemon.enable &&
config.users.ldap.bind.distinguishedName != "";
in
{
###### interface
options = {
users.ldap = {
enable = mkOption {
type = types.bool;
default = false;
description = "Whether to enable authentication against an LDAP server.";
};
server = mkOption {
example = "ldap://ldap.example.org/";
description = "The URL of the LDAP server.";
};
base = mkOption {
example = "dc=example,dc=org";
description = "The distinguished name of the search base.";
};
useTLS = mkOption {
default = false;
description = ''
If enabled, use TLS (encryption) over an LDAP (port 389)
connection. The alternative is to specify an LDAPS server (port
636) in <option>users.ldap.server</option> or to forego
security.
'';
};
timeLimit = mkOption {
default = 0;
type = types.int;
description = ''
Specifies the time limit (in seconds) to use when performing
searches. A value of zero (0), which is the default, is to
wait indefinitely for searches to be completed.
'';
};
daemon = {
enable = mkOption {
default = false;
description = ''
Whether to let the nslcd daemon (nss-pam-ldapd) handle the
LDAP lookups for NSS and PAM. This can improve performance,
and if you need to bind to the LDAP server with a password,
it increases security, since only the nslcd user needs to
have access to the bindpw file, not everyone that uses NSS
and/or PAM. If this option is enabled, a local nscd user is
created automatically, and the nslcd service is started
automatically when the network get up.
'';
};
extraConfig = mkOption {
default = "";
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type = types.lines;
description = ''
Extra configuration options that will be added verbatim at
the end of the nslcd configuration file (nslcd.conf).
'' ;
} ;
};
bind = {
distinguishedName = mkOption {
default = "";
example = "cn=admin,dc=example,dc=com";
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type = types.str;
description = ''
The distinguished name to bind to the LDAP server with. If this
is not specified, an anonymous bind will be done.
'';
};
password = mkOption {
default = "/etc/ldap/bind.password";
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type = types.str;
description = ''
The path to a file containing the credentials to use when binding
to the LDAP server (if not binding anonymously).
'';
};
timeLimit = mkOption {
default = 30;
type = types.int;
description = ''
Specifies the time limit (in seconds) to use when connecting
to the directory server. This is distinct from the time limit
specified in <literal>users.ldap.timeLimit</literal> and affects
the initial server connection only.
'';
};
policy = mkOption {
default = "hard_open";
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type = types.enum [ "hard_open" "hard_init" "soft" ];
description = ''
Specifies the policy to use for reconnecting to an unavailable
LDAP server. The default is <literal>hard_open</literal>, which
reconnects if opening the connection to the directory server
failed. By contrast, <literal>hard_init</literal> reconnects if
initializing the connection failed. Initializing may not
actually contact the directory server, and it is possible that
a malformed configuration file will trigger reconnection. If
<literal>soft</literal> is specified, then
<literal>nss_ldap</literal> will return immediately on server
failure. All hard reconnect policies block with exponential
backoff before retrying.
'';
};
};
extraConfig = mkOption {
default = "";
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type = types.lines;
description = ''
Extra configuration options that will be added verbatim at
the end of the ldap configuration file (ldap.conf).
If <literal>users.ldap.daemon</literal> is enabled, this
configuration will not be used. In that case, use
<literal>users.ldap.daemon.extraConfig</literal> instead.
'' ;
};
};
};
###### implementation
config = mkIf cfg.enable {
environment.etc = if cfg.daemon.enable then [nslcdConfig] else [ldapConfig];
system.activationScripts = mkIf insertLdapPassword {
ldap = stringAfter [ "etc" "groups" "users" ] ''
if test -f "${cfg.bind.password}" ; then
echo "bindpw "$(cat ${cfg.bind.password})"" | cat ${ldapConfig} - > /etc/ldap.conf.bindpw
mv -fT /etc/ldap.conf.bindpw /etc/ldap.conf
chmod 600 /etc/ldap.conf
fi
'';
};
system.nssModules = singleton (
if cfg.daemon.enable then nss_pam_ldapd else nss_ldap
);
users = mkIf cfg.daemon.enable {
extraGroups.nslcd = {
gid = config.ids.gids.nslcd;
};
extraUsers.nslcd = {
uid = config.ids.uids.nslcd;
description = "nslcd user.";
group = "nslcd";
};
};
systemd.services = mkIf cfg.daemon.enable {
nslcd = {
wantedBy = [ "multi-user.target" ];
preStart = ''
mkdir -p /run/nslcd
rm -f /run/nslcd/nslcd.pid;
chown nslcd.nslcd /run/nslcd
${optionalString (cfg.bind.distinguishedName != "") ''
if test -s "${cfg.bind.password}" ; then
ln -sfT "${cfg.bind.password}" /run/nslcd/bindpw
fi
''}
'';
serviceConfig = {
ExecStart = "${nss_pam_ldapd}/sbin/nslcd";
Type = "forking";
PIDFile = "/run/nslcd/nslcd.pid";
Restart = "always";
};
};
};
};
}