home-manager/modules/services/gpg-agent.nix
Naïm Favier 371576cdc2
gpg-agent: remove unnecessary IFD
Make `gpgconf` only perform an import from derivation when the GPG
`homedir` is set to a non-default value, which probably isn't the case
for most users.
2021-09-15 23:09:02 +02:00

308 lines
9.1 KiB
Nix

{ config, options, lib, pkgs, ... }:
with lib;
let
cfg = config.services.gpg-agent;
gpgPkg = config.programs.gpg.package;
homedir = config.programs.gpg.homedir;
gpgInitStr = ''
GPG_TTY="$(tty)"
export GPG_TTY
''
+ optionalString cfg.enableSshSupport
"${gpgPkg}/bin/gpg-connect-agent updatestartuptty /bye > /dev/null";
# mimic `gpgconf` output for use in `systemd` unit definitions.
# we cannot use `gpgconf` directly because it heavily depends on system
# state, but we need the values at build time. original:
# https://github.com/gpg/gnupg/blob/c6702d77d936b3e9d91b34d8fdee9599ab94ee1b/common/homedir.c#L672-L681
gpgconf = dir:
if homedir == options.programs.gpg.homedir.default then
"%t/gnupg/${dir}"
else
builtins.readFile (pkgs.runCommand dir {} ''
PATH=${pkgs.xxd}/bin:$PATH
hash=$(echo -n ${homedir} | sha1sum -b | xxd -r -p | base32 | \
cut -c -24 | tr '[:upper:]' '[:lower:]' | \
tr abcdefghijklmnopqrstuvwxyz234567 \
ybndrfg8ejkmcpqxot1uwisza345h769)
echo -n "%t/gnupg/d.$hash/${dir}" > "$out"
'');
in
{
meta.maintainers = [ maintainers.rycee ];
options = {
services.gpg-agent = {
enable = mkEnableOption "GnuPG private key agent";
defaultCacheTtl = mkOption {
type = types.nullOr types.int;
default = null;
description = ''
Set the time a cache entry is valid to the given number of
seconds.
'';
};
defaultCacheTtlSsh = mkOption {
type = types.nullOr types.int;
default = null;
description = ''
Set the time a cache entry used for SSH keys is valid to the
given number of seconds.
'';
};
maxCacheTtl = mkOption {
type = types.nullOr types.int;
default = null;
description = ''
Set the maximum time a cache entry is valid to n seconds. After this
time a cache entry will be expired even if it has been accessed
recently or has been set using gpg-preset-passphrase. The default is
2 hours (7200 seconds).
'';
};
maxCacheTtlSsh = mkOption {
type = types.nullOr types.int;
default = null;
description = ''
Set the maximum time a cache entry used for SSH keys is valid to n
seconds. After this time a cache entry will be expired even if it has
been accessed recently or has been set using gpg-preset-passphrase.
The default is 2 hours (7200 seconds).
'';
};
enableSshSupport = mkOption {
type = types.bool;
default = false;
description = ''
Whether to use the GnuPG key agent for SSH keys.
'';
};
sshKeys = mkOption {
type = types.nullOr (types.listOf types.str);
default = null;
description = ''
Which GPG keys (by keygrip) to expose as SSH keys.
'';
};
enableExtraSocket = mkOption {
type = types.bool;
default = false;
description = ''
Whether to enable extra socket of the GnuPG key agent (useful for GPG
Agent forwarding).
'';
};
verbose = mkOption {
type = types.bool;
default = false;
description = ''
Whether to produce verbose output.
'';
};
grabKeyboardAndMouse = mkOption {
type = types.bool;
default = true;
description = ''
Tell the pinentry to grab the keyboard and mouse. This
option should in general be used to avoid X-sniffing
attacks. When disabled, this option passes
<option>no-grab</option> setting to gpg-agent.
'';
};
enableScDaemon = mkOption {
type = types.bool;
default = true;
description = ''
Make use of the scdaemon tool. This option has the effect of
enabling the ability to do smartcard operations. When
disabled, this option passes
<option>disable-scdaemon</option> setting to gpg-agent.
'';
};
extraConfig = mkOption {
type = types.lines;
default = "";
example = ''
allow-emacs-pinentry
allow-loopback-pinentry
'';
description = ''
Extra configuration lines to append to the gpg-agent
configuration file.
'';
};
pinentryFlavor = mkOption {
type = types.nullOr (types.enum pkgs.pinentry.flavors);
example = "gnome3";
default = "gtk2";
description = ''
Which pinentry interface to use. If not
<literal>null</literal>, it sets
<option>pinentry-program</option> in
<filename>gpg-agent.conf</filename>. Beware that
<literal>pinentry-gnome3</literal> may not work on non-Gnome
systems. You can fix it by adding the following to your
system configuration:
<programlisting language="nix">
services.dbus.packages = [ pkgs.gcr ];
</programlisting>
For this reason, the default is <literal>gtk2</literal> for
now.
'';
};
};
};
config = mkIf cfg.enable (mkMerge [
{
home.file."${homedir}/gpg-agent.conf".text = concatStringsSep "\n" (
optional (cfg.enableSshSupport) "enable-ssh-support"
++
optional (!cfg.grabKeyboardAndMouse) "no-grab"
++
optional (!cfg.enableScDaemon) "disable-scdaemon"
++
optional (cfg.defaultCacheTtl != null)
"default-cache-ttl ${toString cfg.defaultCacheTtl}"
++
optional (cfg.defaultCacheTtlSsh != null)
"default-cache-ttl-ssh ${toString cfg.defaultCacheTtlSsh}"
++
optional (cfg.maxCacheTtl != null)
"max-cache-ttl ${toString cfg.maxCacheTtl}"
++
optional (cfg.maxCacheTtlSsh != null)
"max-cache-ttl-ssh ${toString cfg.maxCacheTtlSsh}"
++
optional (cfg.pinentryFlavor != null)
"pinentry-program ${pkgs.pinentry.${cfg.pinentryFlavor}}/bin/pinentry"
++
[ cfg.extraConfig ]
);
home.sessionVariablesExtra = optionalString cfg.enableSshSupport ''
if [[ -z "$SSH_AUTH_SOCK" ]]; then
export SSH_AUTH_SOCK="$(${gpgPkg}/bin/gpgconf --list-dirs agent-ssh-socket)"
fi
'';
programs.bash.initExtra = gpgInitStr;
programs.zsh.initExtra = gpgInitStr;
programs.fish.interactiveShellInit = ''
set -gx GPG_TTY (tty)
'';
}
(mkIf (cfg.sshKeys != null) {
# Trailing newlines are important
home.file."${homedir}/sshcontrol".text = concatMapStrings (s: "${s}\n") cfg.sshKeys;
})
# The systemd units below are direct translations of the
# descriptions in the
#
# ${gpgPkg}/share/doc/gnupg/examples/systemd-user
#
# directory.
{
systemd.user.services.gpg-agent = {
Unit = {
Description = "GnuPG cryptographic agent and passphrase cache";
Documentation = "man:gpg-agent(1)";
Requires = "gpg-agent.socket";
After = "gpg-agent.socket";
# This is a socket-activated service:
RefuseManualStart = true;
};
Service = {
ExecStart = "${gpgPkg}/bin/gpg-agent --supervised"
+ optionalString cfg.verbose " --verbose";
ExecReload = "${gpgPkg}/bin/gpgconf --reload gpg-agent";
Environment = "GNUPGHOME=${homedir}";
};
};
systemd.user.sockets.gpg-agent = {
Unit = {
Description = "GnuPG cryptographic agent and passphrase cache";
Documentation = "man:gpg-agent(1)";
};
Socket = {
ListenStream = gpgconf "S.gpg-agent";
FileDescriptorName = "std";
SocketMode = "0600";
DirectoryMode = "0700";
};
Install = {
WantedBy = [ "sockets.target" ];
};
};
}
(mkIf cfg.enableSshSupport {
systemd.user.sockets.gpg-agent-ssh = {
Unit = {
Description = "GnuPG cryptographic agent (ssh-agent emulation)";
Documentation = "man:gpg-agent(1) man:ssh-add(1) man:ssh-agent(1) man:ssh(1)";
};
Socket = {
ListenStream = gpgconf "S.gpg-agent.ssh";
FileDescriptorName = "ssh";
Service = "gpg-agent.service";
SocketMode = "0600";
DirectoryMode = "0700";
};
Install = {
WantedBy = [ "sockets.target" ];
};
};
})
(mkIf cfg.enableExtraSocket {
systemd.user.sockets.gpg-agent-extra = {
Unit = {
Description = "GnuPG cryptographic agent and passphrase cache (restricted)";
Documentation = "man:gpg-agent(1) man:ssh(1)";
};
Socket = {
ListenStream = gpgconf "S.gpg-agent.extra";
FileDescriptorName = "extra";
Service = "gpg-agent.service";
SocketMode = "0600";
DirectoryMode = "0700";
};
Install = {
WantedBy = [ "sockets.target" ];
};
};
})
]);
}