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nixpkgs/nixos/modules/security/pam.nix
Shea Levy 1d62ad4746 modules.nix: Generate the extra argument set from the configuration
This allows for module arguments to be handled modularly, in particular
allowing the nixpkgs module to handle the nixpkgs import internally.
This creates the __internal option namespace, which should only be added
to by the module system itself.
2015-03-12 23:42:57 +01:00

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# This module provides configuration for the PAM (Pluggable
# Authentication Modules) system.
{ config, lib, pkgs, ... }:
with lib;
let
parentConfig = config;
pamOpts = { config, name, ... }: let cfg = config; in let config = parentConfig; in {
options = {
name = mkOption {
example = "sshd";
type = types.str;
description = "Name of the PAM service.";
};
unixAuth = mkOption {
default = true;
type = types.bool;
description = ''
Whether users can log in with passwords defined in
<filename>/etc/shadow</filename>.
'';
};
rootOK = mkOption {
default = false;
type = types.bool;
description = ''
If set, root doesn't need to authenticate (e.g. for the
<command>useradd</command> service).
'';
};
usbAuth = mkOption {
default = config.security.pam.usb.enable;
type = types.bool;
description = ''
If set, users listed in
<filename>/etc/pamusb.conf</filename> are able to log in
with the associated USB key.
'';
};
otpwAuth = mkOption {
default = config.security.pam.enableOTPW;
type = types.bool;
description = ''
If set, the OTPW system will be used (if
<filename>~/.otpw</filename> exists).
'';
};
fprintAuth = mkOption {
default = config.services.fprintd.enable;
type = types.bool;
description = ''
If set, fingerprint reader will be used (if exists and
your fingerprints are enrolled).
'';
};
oathAuth = mkOption {
default = config.security.pam.enableOATH;
type = types.bool;
description = ''
If set, the OATH Toolkit will be used.
'';
};
sshAgentAuth = mkOption {
default = false;
type = types.bool;
description = ''
If set, the calling user's SSH agent is used to authenticate
against the keys in the calling user's
<filename>~/.ssh/authorized_keys</filename>. This is useful
for <command>sudo</command> on password-less remote systems.
'';
};
startSession = mkOption {
default = false;
type = types.bool;
description = ''
If set, the service will register a new session with
systemd's login manager. For local sessions, this will give
the user access to audio devices, CD-ROM drives. In the
default PolicyKit configuration, it also allows the user to
reboot the system.
'';
};
setLoginUid = mkOption {
type = types.bool;
description = ''
Set the login uid of the process
(<filename>/proc/self/loginuid</filename>) for auditing
purposes. The login uid is only set by entry points like
<command>login</command> and <command>sshd</command>, not by
commands like <command>sudo</command>.
'';
};
forwardXAuth = mkOption {
default = false;
type = types.bool;
description = ''
Whether X authentication keys should be passed from the
calling user to the target user (e.g. for
<command>su</command>)
'';
};
allowNullPassword = mkOption {
default = false;
type = types.bool;
description = ''
Whether to allow logging into accounts that have no password
set (i.e., have an empty password field in
<filename>/etc/passwd</filename> or
<filename>/etc/group</filename>). This does not enable
logging into disabled accounts (i.e., that have the password
field set to <literal>!</literal>). Note that regardless of
what the pam_unix documentation says, accounts with hashed
empty passwords are always allowed to log in.
'';
};
requireWheel = mkOption {
default = false;
type = types.bool;
description = ''
Whether to permit root access only to members of group wheel.
'';
};
limits = mkOption {
description = ''
Attribute set describing resource limits. Defaults to the
value of <option>security.pam.loginLimits</option>.
'';
};
showMotd = mkOption {
default = false;
type = types.bool;
description = "Whether to show the message of the day.";
};
makeHomeDir = mkOption {
default = false;
type = types.bool;
description = ''
Whether to try to create home directories for users
with <literal>$HOME</literal>s pointing to nonexistent
locations on session login.
'';
};
updateWtmp = mkOption {
default = false;
type = types.bool;
description = "Whether to update <filename>/var/log/wtmp</filename>.";
};
logFailures = mkOption {
default = false;
type = types.bool;
description = "Whether to log authentication failures in <filename>/var/log/faillog</filename>.";
};
text = mkOption {
type = types.nullOr types.lines;
description = "Contents of the PAM service file.";
};
};
config = {
name = mkDefault name;
setLoginUid = mkDefault cfg.startSession;
limits = mkDefault config.security.pam.loginLimits;
# !!! TODO: move the LDAP stuff to the LDAP module, and the
# Samba stuff to the Samba module. This requires that the PAM
# module provides the right hooks.
text = mkDefault
''
# Account management.
account sufficient pam_unix.so
${optionalString config.users.ldap.enable
"account sufficient ${pam_ldap}/lib/security/pam_ldap.so"}
${optionalString config.krb5.enable
"account sufficient ${pam_krb5}/lib/security/pam_krb5.so"}
# Authentication management.
${optionalString cfg.rootOK
"auth sufficient pam_rootok.so"}
${optionalString cfg.requireWheel
"auth required pam_wheel.so use_uid"}
${optionalString cfg.logFailures
"auth required pam_tally.so"}
${optionalString (config.security.pam.enableSSHAgentAuth && cfg.sshAgentAuth)
"auth sufficient ${pkgs.pam_ssh_agent_auth}/libexec/pam_ssh_agent_auth.so file=~/.ssh/authorized_keys:~/.ssh/authorized_keys2:/etc/ssh/authorized_keys.d/%u"}
${optionalString cfg.fprintAuth
"auth sufficient ${pkgs.fprintd}/lib/security/pam_fprintd.so"}
${optionalString cfg.usbAuth
"auth sufficient ${pkgs.pam_usb}/lib/security/pam_usb.so"}
${optionalString cfg.unixAuth
"auth ${if config.security.pam.enableEcryptfs then "required" else "sufficient"} pam_unix.so ${optionalString cfg.allowNullPassword "nullok"} likeauth"}
${optionalString config.security.pam.enableEcryptfs
"auth required ${pkgs.ecryptfs}/lib/security/pam_ecryptfs.so unwrap"}
${optionalString cfg.otpwAuth
"auth sufficient ${pkgs.otpw}/lib/security/pam_otpw.so"}
${optionalString cfg.oathAuth
"auth sufficient ${pkgs.oathToolkit}/lib/security/pam_oath.so window=5 usersfile=/etc/users.oath"}
${optionalString config.users.ldap.enable
"auth sufficient ${pam_ldap}/lib/security/pam_ldap.so use_first_pass"}
${optionalString config.krb5.enable ''
auth [default=ignore success=1 service_err=reset] ${pam_krb5}/lib/security/pam_krb5.so use_first_pass
auth [default=die success=done] ${pam_ccreds}/lib/security/pam_ccreds.so action=validate use_first_pass
auth sufficient ${pam_ccreds}/lib/security/pam_ccreds.so action=store use_first_pass
''}
${optionalString (! config.security.pam.enableEcryptfs) "auth required pam_deny.so"}
# Password management.
${optionalString config.security.pam.enableEcryptfs
"password optional ${pkgs.ecryptfs}/lib/security/pam_ecryptfs.so"}
password requisite pam_unix.so nullok sha512
${optionalString config.users.ldap.enable
"password sufficient ${pam_ldap}/lib/security/pam_ldap.so"}
${optionalString config.krb5.enable
"password sufficient ${pam_krb5}/lib/security/pam_krb5.so use_first_pass"}
${optionalString config.services.samba.syncPasswordsByPam
"password optional ${pkgs.samba}/lib/security/pam_smbpass.so nullok use_authtok try_first_pass"}
# Session management.
session required pam_env.so envfile=${config.system.build.pamEnvironment}
session required pam_unix.so
${optionalString cfg.setLoginUid
"session ${
if config.boot.isContainer then "optional" else "required"
} pam_loginuid.so"}
${optionalString cfg.makeHomeDir
"session required ${pkgs.pam}/lib/security/pam_mkhomedir.so silent skel=/etc/skel umask=0022"}
${optionalString cfg.updateWtmp
"session required ${pkgs.pam}/lib/security/pam_lastlog.so silent"}
${optionalString config.security.pam.enableEcryptfs
"session optional ${pkgs.ecryptfs}/lib/security/pam_ecryptfs.so"}
${optionalString config.users.ldap.enable
"session optional ${pam_ldap}/lib/security/pam_ldap.so"}
${optionalString config.krb5.enable
"session optional ${pam_krb5}/lib/security/pam_krb5.so"}
${optionalString cfg.otpwAuth
"session optional ${pkgs.otpw}/lib/security/pam_otpw.so"}
${optionalString cfg.oathAuth
"session optional ${pkgs.oathToolkit}/lib/security/pam_oath.so window=5 usersfile=/etc/users.oath"}
${optionalString cfg.startSession
"session optional ${pkgs.systemd}/lib/security/pam_systemd.so"}
${optionalString cfg.forwardXAuth
"session optional pam_xauth.so xauthpath=${pkgs.xorg.xauth}/bin/xauth systemuser=99"}
${optionalString (cfg.limits != [])
"session required ${pkgs.pam}/lib/security/pam_limits.so conf=${makeLimitsConf cfg.limits}"}
${optionalString (cfg.showMotd && config.users.motd != null)
"session optional ${pkgs.pam}/lib/security/pam_motd.so motd=${motd}"}
'';
};
};
inherit (pkgs) pam_krb5 pam_ccreds;
pam_ldap = if config.users.ldap.daemon.enable then pkgs.nss_pam_ldapd else pkgs.pam_ldap;
# Create a limits.conf(5) file.
makeLimitsConf = limits:
pkgs.writeText "limits.conf"
(concatMapStrings ({ domain, type, item, value }:
"${domain} ${type} ${item} ${toString value}\n")
limits);
motd = pkgs.writeText "motd" config.users.motd;
makePAMService = pamService:
{ source = pkgs.writeText "${pamService.name}.pam" pamService.text;
target = "pam.d/${pamService.name}";
};
in
{
###### interface
options = {
security.pam.loginLimits = mkOption {
default = [];
example =
[ { domain = "ftp";
type = "hard";
item = "nproc";
value = "0";
}
{ domain = "@student";
type = "-";
item = "maxlogins";
value = "4";
}
];
description =
'' Define resource limits that should apply to users or groups.
Each item in the list should be an attribute set with a
<varname>domain</varname>, <varname>type</varname>,
<varname>item</varname>, and <varname>value</varname>
attribute. The syntax and semantics of these attributes
must be that described in the limits.conf(5) man page.
'';
};
security.pam.services = mkOption {
default = [];
type = types.loaOf types.optionSet;
options = [ pamOpts ];
description =
''
This option defines the PAM services. A service typically
corresponds to a program that uses PAM,
e.g. <command>login</command> or <command>passwd</command>.
Each attribute of this set defines a PAM service, with the attribute name
defining the name of the service.
'';
};
security.pam.enableSSHAgentAuth = mkOption {
default = false;
description =
''
Enable sudo logins if the user's SSH agent provides a key
present in <filename>~/.ssh/authorized_keys</filename>.
This allows machines to exclusively use SSH keys instead of
passwords.
'';
};
security.pam.enableOTPW = mkOption {
default = false;
description = ''
Enable the OTPW (one-time password) PAM module.
'';
};
security.pam.enableOATH = mkOption {
default = false;
description = ''
Enable the OATH (one-time password) PAM module.
'';
};
security.pam.enableEcryptfs = mkOption {
default = false;
description = ''
Enable eCryptfs PAM module (mounting ecryptfs home directory on login).
'';
};
users.motd = mkOption {
default = null;
example = "Today is Sweetmorn, the 4th day of The Aftermath in the YOLD 3178.";
type = types.nullOr types.string;
description = "Message of the day shown to users when they log in.";
};
};
###### implementation
config = {
environment.systemPackages =
# Include the PAM modules in the system path mostly for the manpages.
[ pkgs.pam ]
++ optional config.users.ldap.enable pam_ldap
++ optionals config.krb5.enable [pam_krb5 pam_ccreds]
++ optionals config.security.pam.enableOTPW [ pkgs.otpw ]
++ optionals config.security.pam.enableOATH [ pkgs.oathToolkit ]
++ optionals config.security.pam.enableEcryptfs [ pkgs.ecryptfs ];
security.setuidPrograms =
optionals config.security.pam.enableEcryptfs [ "mount.ecryptfs_private" "umount.ecryptfs_private" ];
environment.etc =
mapAttrsToList (n: v: makePAMService v) config.security.pam.services;
security.setuidOwners = [ {
program = "unix_chkpwd";
source = "${pkgs.pam}/sbin/unix_chkpwd.orig";
owner = "root";
setuid = true;
} ];
security.pam.services =
{ other.text =
''
auth required pam_warn.so
auth required pam_deny.so
account required pam_warn.so
account required pam_deny.so
password required pam_warn.so
password required pam_deny.so
session required pam_warn.so
session required pam_deny.so
'';
# Most of these should be moved to specific modules.
cups = {};
ftp = {};
i3lock = {};
screen = {};
vlock = {};
xlock = {};
xscreensaver = {};
};
};
}