This commit is contained in:
John Lancaster
2026-07-05 20:40:28 -05:00
parent ca75da7c37
commit 39504cd856
3 changed files with 6 additions and 37 deletions
+285
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# New attempt at consolidating SSH config that wraps the step client, SSH certs, and all that in a top-level module
{ self, inputs, ... }:
let
caPatterns = [ "*.john-stream.com" "192.168.1.*" "fded:fb16:653e:25da:be24:11ff:*" ];
sshHostCAPath = ../../hosts/janus/public/ssh_host_ca_key.pub;
in
{
flake.modules.nixos.ssh-new = { config, pkgs, lib, ... }:
let
cfg = config.ssh-new;
hostKeyFile = "${cfg.host.configDir}/${cfg.host.keyFile}";
hostCertFile = "${hostKeyFile}-cert.pub";
userCAFile = "${cfg.host.configDir}/${cfg.certificates.user.CAFile}";
CAknownHosts = (lib.genAttrs caPatterns (_: {
certAuthority = true;
publicKey = lib.removeSuffix "\n" (builtins.readFile sshHostCAPath);
}));
wrappers = inputs.self.wrappers;
provisionerPasswordFile = config.sops.secrets."janus/admin_jwk".path;
sshHostCertSign = (wrappers.signHostWrapper.apply {
inherit pkgs provisionerPasswordFile;
inherit (cfg.certificates) provisioner;
inherit (cfg.certificates.host) extraPrincipals;
}).wrapper;
sshHostCertRenew = (wrappers.renewHostWrapper.apply {
inherit pkgs;
sshHostKeyFile = hostKeyFile;
overwrite = true;
}).wrapper;
sshHostCertCheck = (wrappers.hostCheckWrapper.apply {
inherit pkgs;
certPath = hostCertFile;
}).wrapper;
sshHostRenewalCheck = (wrappers.renewalCheck.apply {
inherit pkgs;
certPath = hostCertFile;
expires-in = "4h";
}).wrapper;
sshUserCertSign = (wrappers.signUserWrapper.apply {
inherit pkgs provisionerPasswordFile;
inherit (cfg.certificates) provisioner;
validUsers = [ "root" "john" "appdaemon" ];
}).wrapper;
sshUserCertCheck = (wrappers.userCheckWrapper.apply {
inherit pkgs;
certPath = "${cfg.user.keyFile}-cert.pub";
}).wrapper;
in
{
options.ssh-new = {
user = {
keyFile = lib.mkOption {
type = lib.types.str;
default = "$HOME/.ssh/id_ed25519";
};
};
host = {
configDir = lib.mkOption {
type = lib.types.str;
default = "/etc/ssh";
};
keyFile = lib.mkOption {
description = "String path to the host private key file";
type = lib.types.str;
default = "ssh_host_ed25519_key";
};
keyType = lib.mkOption {
description = "OpenSSH host key type for ssh.hostKey.";
type = lib.types.enum [ "ed25519" "rsa" "ecdsa" ];
default = "ed25519";
};
extraSettings = lib.mkOption {
description = "Extra settings to merge";
type = lib.types.attrs;
default = { };
};
};
certificates = {
provisioner = lib.mkOption {
type = lib.types.nullOr lib.types.str;
};
host = {
enable = lib.mkEnableOption "Enable SSH host certs";
autoRenew = lib.mkEnableOption "Auto-renew the SSH host certs with a systemd service/timer";
extraPrincipals = lib.mkOption {
type = lib.types.listOf lib.types.str;
default = [ ];
};
};
user = {
enable = lib.mkEnableOption "Enable SSH user certs";
CAFile = lib.mkOption {
description = "Filename of the SSH user CA with the config directory";
type = lib.types.str;
default = "ssh_user_ca_key.pub";
};
extraPrincipals = lib.mkOption {
type = lib.types.listOf lib.types.str;
default = [ ];
};
};
};
};
config = {
services.openssh = {
enable = true;
openFirewall = true;
hostKeys = [
{
path = hostKeyFile;
type = cfg.host.keyType;
}
];
settings = lib.mkMerge [
{
PasswordAuthentication = false;
KbdInteractiveAuthentication = false;
}
cfg.host.extraSettings
(lib.mkIf cfg.certificates.host.enable {
HostCertificate = "${hostKeyFile}-cert.pub";
})
(lib.mkIf cfg.certificates.user.enable {
TrustedUserCAKeys = "${cfg.host.configDir}/${cfg.certificates.user.CAFile}";
})
];
};
environment.etc."ssh/${cfg.certificates.user.CAFile}" = lib.mkIf cfg.certificates.user.enable {
source = ../../hosts/janus/public/ssh_user_ca_key.pub;
};
environment.systemPackages = (
lib.optionals cfg.certificates.host.enable [
sshHostCertSign
sshHostCertRenew
sshHostRenewalCheck
sshHostCertCheck
]
);
sops = lib.mkIf cfg.certificates.host.autoRenew {
secrets."janus/admin_jwk" = {
sopsFile = ../../../keys/secrets.yaml;
owner = "root";
group = "root";
mode = "0400";
};
};
systemd = lib.mkIf cfg.certificates.host.autoRenew {
services.ssh-certs-renew = {
description = "SSH host certificate renewal";
wantedBy = [ "multi-user.target" ];
after = [ "network-online.target" ];
wants = [ "network-online.target" ];
path = with pkgs; [ step-cli systemd ];
serviceConfig = {
Type = "oneshot";
User = "root";
Group = "root";
ExecCondition = lib.getExe sshHostRenewalCheck;
ExecStart = lib.getExe sshHostCertRenew;
};
};
timers.ssh-certs-renew = {
description = "Periodic Step SSH host certificate renewal";
wantedBy = [ "timers.target" ];
timerConfig = {
OnBootSec = "5m";
OnUnitActiveSec = "4h";
RandomizedDelaySec = "15m";
Persistent = true;
Unit = "ssh-certs-renew.service";
};
};
};
# This winds up in /etc/ssh/ssh_known_hosts, which applies to all users
programs.ssh.knownHosts = lib.mkIf cfg.certificates.user.enable CAknownHosts;
home-manager.users.root = lib.mkIf cfg.certificates.user.enable {
home.stateVersion = lib.mkDefault config.system.stateVersion;
imports = with inputs.self.modules.homeManager; [
ssh-new
];
home.packages = [
sshUserCertSign
sshUserCertCheck
];
ssh-new.certificates.enable = true;
};
};
};
flake.modules.homeManager.ssh-new = { config, pkgs, lib, ... }:
let
cfg = config.ssh-new;
sshHostCAContent = lib.removeSuffix "\n" (builtins.readFile sshHostCAPath);
knownHostsText = lib.concatMapStrings
(pattern: "@cert-authority ${pattern} ${sshHostCAContent}\n")
caPatterns;
in
{
options.ssh-new = {
keyFile = lib.mkOption {
type = lib.types.str;
default = "${config.home.homeDirectory}/.ssh/id_ed25519";
};
certificates = {
enable = lib.mkEnableOption "Enable SSH client certificates";
};
};
config = {
home.file.".ssh/known_hosts" = lib.mkIf cfg.certificates.enable {
text = knownHostsText;
};
programs.ssh = {
enable = true;
enableDefaultConfig = false;
settings = {
# These settings apply to all connections
"*" = lib.mkMerge (
[
# Default settings
{
Compression = false;
ServerAliveInterval = 60;
ServerAliveCountMax = 3;
TCPKeepAlive = "yes";
ConnectTimeout = 3;
PubkeyAuthentication = "yes";
PasswordAuthentication = "no";
PreferredAuthentications = "publickey";
IdentitiesOnly = true;
IdentityFile = cfg.keyFile;
StrictHostKeyChecking = "accept-new";
UserKnownHostsFile = "${config.home.homeDirectory}/.ssh/known_hosts";
HashKnownHosts = lib.mkDefault false;
AddKeysToAgent = lib.mkDefault "yes";
ForwardAgent = lib.mkDefault false;
RequestTTY = lib.mkDefault "auto";
SetEnv.TERM = "xterm-256color";
}
]
# SSH certificate settings
++ lib.optionals cfg.certificates.enable [
{
CertificateFile = "${cfg.keyFile}-cert.pub";
}
]
);
"gitea" = {
HostName = "192.168.1.104";
User = "john";
};
"janus" = {
HostName = "fded:fb16:653e:25da:be24:11ff:fe6b:4d57";
User = "root";
};
"soteria" = {
HostName = "fded:fb16:653e:25da:be24:11ff:fe54:aa39";
User = "root";
};
"hermes" = {
HostName = "192.168.1.150";
User = "root";
};
"jdl-docker" = {
HostName = "jdl-docker.tailcf205.ts.net";
User = "john";
};
};
};
};
};
}
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{ self, inputs, ... }:
let
mkPrincipalArgs = principals:
builtins.concatLists (map (principal: [ "--principal" principal ]) principals);
in
{
flake.wrappers.signHostWrapper = inputs.wrappers.lib.wrapModule ({config, lib, wlib, ... }: {
options = {
provisioner = lib.mkOption {
type = lib.types.nullOr lib.types.str;
default = "admin";
};
provisionerPasswordFile = lib.mkOption {
type = lib.types.nullOr lib.types.str;
};
extraPrincipals = lib.mkOption {
type = lib.types.listOf lib.types.str;
default = [ ];
};
overwrite = lib.mkEnableOption "Overwrite existing cert file?";
};
config = {
binName = "ssh-host-cert-sign";
package = config.pkgs.step-cli;
extraPackages = with config.pkgs; [ hostname iproute2 systemd ];
preHook = ''
HOSTNAME=$(hostname -s)
IP_ADDRESS=$(ip -4 -o addr show scope global | while read -r _ _ _ addr _; do
case "$addr" in
192.168.1.*/*)
printf '%s\n' "''${addr%%/*}"
break
;;
esac
done)
echo "Signing SSH host cert for $HOSTNAME at $IP_ADDRESS"
'';
args =
[
"ssh" "certificate"
"--host" "--sign"
"--principal" "$HOSTNAME"
"--principal" "$IP_ADDRESS"
]
++ lib.optionals (config.provisioner != null) [ "--provisioner" "${config.provisioner}" ]
++ lib.optionals (config.provisionerPasswordFile != null) [
"--provisioner-password-file" "${config.provisionerPasswordFile}"
]
++ lib.optionals config.overwrite [ "-f" ]
++ mkPrincipalArgs config.extraPrincipals;
};
});
flake.wrappers.renewHostWrapper = inputs.wrappers.lib.wrapModule ({config, lib, wlib, ... }: {
options = {
sshHostKeyFile = lib.mkOption {
type = lib.types.str;
default = "/etc/ssh/ssh_host_ed25519_key";
};
overwrite = lib.mkEnableOption "Overwrite existing cert file?";
};
config = {
binName = "ssh-host-cert-renew";
package = config.pkgs.step-cli;
extraPackages = with config.pkgs; [ systemd ];
args =
[ "ssh" "renew" "${config.sshHostKeyFile}-cert.pub" "${config.sshHostKeyFile}" ]
++ lib.optionals config.overwrite [ "-f" ];
};
});
flake.wrappers.hostCheckWrapper = inputs.wrappers.lib.wrapModule ({config, lib, wlib, ... }: {
options = {
certPath = lib.mkOption {
type = lib.types.nullOr lib.types.str;
default = "/etc/ssh/ssh_host_ed25519_key-cert.pub";
};
};
config = {
binName = "ssh-host-cert-check";
package = config.pkgs.openssh;
exePath = lib.getExe' config.pkgs.openssh "ssh-keygen";
args = [ "-Lf" "${config.certPath}" ];
};
});
flake.wrappers.signUserWrapper = inputs.wrappers.lib.wrapModule ({config, lib, wlib, ... }: {
options = {
provisioner = lib.mkOption {
type = lib.types.nullOr lib.types.str;
default = "admin";
};
provisionerPasswordFile = lib.mkOption {
type = lib.types.nullOr lib.types.str;
};
validUsers = lib.mkOption {
description = "A list of the user names that this cert will be valid for";
type = lib.types.listOf lib.types.str;
default = [ ];
};
overwrite = lib.mkEnableOption "Overwrite existing cert file?";
};
config = {
binName = "ssh-user-cert-sign";
package = config.pkgs.step-cli;
args = [ "ssh" "certificate" "--sign" ]
++ lib.optionals (config.provisioner != null) [ "--provisioner" "${config.provisioner}" ]
++ lib.optionals (config.provisionerPasswordFile != null) [
"--provisioner-password-file" "${config.provisionerPasswordFile}"
]
++ lib.optionals config.overwrite [ "-f" ]
++ mkPrincipalArgs config.validUsers;
};
});
flake.wrappers.userCheckWrapper = inputs.wrappers.lib.wrapModule ({config, lib, wlib, ... }: {
options = {
certPath = lib.mkOption {
type = lib.types.nullOr lib.types.str;
default = "$HOME/.ssh/id_ed25519-cert.pub";
};
};
config = {
binName = "ssh-user-cert-check";
package = config.pkgs.openssh;
exePath = lib.getExe' config.pkgs.openssh "ssh-keygen";
args = [ "-Lf" "${config.certPath}" ];
};
});
flake.wrappers.renewalCheck = inputs.wrappers.lib.wrapModule ({config, lib, wlib, ... }: {
options = {
certPath = lib.mkOption {
type = lib.types.nullOr lib.types.str;
default = "$HOME/.ssh/id_ed25519-cert.pub";
};
expires-in = lib.mkOption {
type = lib.types.str;
default = "4h";
};
};
config = {
binName = "ssh-renewal-check";
package = config.pkgs.step-cli;
preHook = ''
echo "Checking SSH cert at ${config.certPath}"
'';
args = [
"ssh" "needs-renewal" "${config.certPath}"
"--expires-in" "${config.expires-in}"
];
};
});
}