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|
{ config, lib, pkgs, ... }:
with lib; let
cfg = config.local.auth.openssh;
withOath = config.local.auth.oath.enable;
withPassword = config.local.auth.openssh.passwordAuthentication;
port = if cfg.shiftPortNumber then 2234 else 22;
restrict = cfg.restrictListen;
exemptList = optionals config.local.net.fail2ban.enable config.services.fail2ban.ignoreIP;
in
{
options.local.auth.openssh = {
enable = mkEnableOption "openssh";
tunnel.enable = mkEnableOption "ssh tunnel user";
#TODO: Desfasar ecdsa, inseguro
hostKeys = listToAttrs (map
(name: {
inherit name;
value = mkOption {
type = types.bool;
default = false;
};
}) [ "ecdsa" "ed25519" "rsa" ]);
restrictListen = mkOption {
default = null;
type = with types; nullOr (submodule {
options = {
addresses = mkOption {
type = listOf str;
};
interface = mkOption {
type = nullOr str;
default = null;
};
vsockCid = mkOption {
type = nullOr ints.u32;
default = null;
};
};
});
};
passwordAuthentication = mkOption {
type = types.bool;
default = false;
};
shiftPortNumber = mkOption {
type = types.bool;
default = true;
};
withDeployKeys = mkOption {
type = types.bool;
default = false;
};
};
config = lib.mkIf cfg.enable {
assertions = [
{
assertion = cfg.tunnel.enable -> withOath;
message = "SSH tunnel requires oath";
}
{
assertion = restrict != null -> (restrict.vsockCid != null -> (restrict.interface == null && restrict.addresses == [ ]));
message = "SSH vsock restrict requires disabling inet";
}
{
assertion = restrict != null -> (restrict.vsockCid != null -> config.services.openssh.startWhenNeeded);
message = "SSH vsock restrict requires socket activation";
}
{
assertion = restrict != null -> (restrict.vsockCid != null -> config.local.virt.enable);
message = "SSH vsock restrict requires nixvirt";
}
{
assertion = any (key: key) (attrValues cfg.hostKeys);
message = "No OpenSSH host keys were enabled";
}
];
local.boot.impermanence.files =
flatten (map (key: [ key.path "${key.path}.pub" ]) config.services.openssh.hostKeys);
networking.firewall = {
interfaces = optionalAttrs (restrict != null && restrict.interface != null) {
${restrict.interface}.allowedTCPPorts = [ port ];
};
allowedTCPPorts = optional (restrict == null || restrict.interface == null) port;
};
services.openssh = {
enable = true;
ports = optional (restrict != null -> restrict.addresses != [ ]) port;
startWhenNeeded = mkDefault (!config.services.fail2ban.enable);
extraConfig = optionalString (exemptList != [ ]) ''
PerSourcePenaltyExemptList ${concatStringsSep "," exemptList}
'' + optionalString cfg.tunnel.enable ''
# User 'tunnel' has no password. Use PAM OATH
# and connect with -N, forward with -R.
Match User tunnel
AllowTcpForwarding remote
AllowStreamLocalForwarding no
X11Forwarding no
PermitTunnel no
GatewayPorts no
AllowAgentForwarding no
PermitOpen none
PermitListen 60220 60221 60222 60223 60224 60225 60226 60227 60228 60229
Banner ${pkgs.writeText "tunnel-banner" ''
This is a reverse tunnel
''}
'';
hostKeys = map
(name: {
path = "/etc/ssh/ssh_host_${name}_key";
type = name;
} // optionalAttrs (name == "rsa") {
bits = 4096;
})
(attrNames (filterAttrs (name: enable: enable) cfg.hostKeys));
settings = {
X11Forwarding = config.local.seat.enable && config.local.seat.graphical;
PermitRootLogin = "prohibit-password";
PasswordAuthentication = withOath || withPassword; # Necesario para oath, no reemplaza a oath
};
listenAddresses = mkIf (restrict != null)
(map (addr: { inherit addr; }) restrict.addresses);
};
systemd.sockets = mkIf (restrict != null && restrict.vsockCid != null) {
sshd =
let
kernelMod = "modprobe@${if restrict.vsockCid == 2 then "vhost_" else ""}vsock.service";
in
{
after = [ kernelMod ];
wants = [ kernelMod ];
socketConfig.ListenStream = mkForce [ "vsock:${toString restrict.vsockCid}:${toString port}" ];
};
};
users.users = {
root = mkIf cfg.withDeployKeys {
openssh.authorizedKeys.keyFiles = [ ./ssh-key.pub ];
};
tunnel = mkIf cfg.tunnel.enable {
uid = 1100;
group = "nogroup";
isSystemUser = true;
# Requiere oath
password = "tunnel";
home = "/var/empty";
shell = "${pkgs.coreutils}/bin/true";
};
};
};
}
|
