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|
{
flake.modules.nixos.openssh =
{
lib,
pkgs,
...
}:
{
services.openssh = {
enable = true;
ports = [ 8693 ];
settings = {
AllowTcpForwarding = false;
AllowAgentForwarding = false;
PasswordAuthentication = false;
X11Forwarding = false;
PermitRootLogin = "yes";
};
};
networking.firewall.allowedTCPPorts = [ 8693 ];
services.fail2ban = {
enable = true;
bantime = lib.mkDefault "1h";
jails = {
sshd = {
enabled = true;
settings = {
port = 8693;
backend = "systemd";
maxretry = 4;
findtime = "10m";
};
};
};
};
security.pam.services.sshd.text = lib.mkDefault (
lib.mkAfter ''
session optional pam_exec.so ${pkgs.writeShellScript "ssh-login-notify" ''
if [ "$PAM_TYPE" = "open_session" ]; then
TIMESTAMP=$(${pkgs.coreutils}/bin/date "+%Y-%m-%d %H:%M:%S %Z")
HOSTNAME=$(${pkgs.coreutils}/bin/cat /etc/hostname)
(
${pkgs.coreutils}/bin/echo "To: leander@schererleander.de"
${pkgs.coreutils}/bin/echo "From: root@sachiel.schererleander.de"
${pkgs.coreutils}/bin/echo "Subject: SSH Login Alert: $PAM_USER"
${pkgs.coreutils}/bin/echo "Content-Type: text/html; charset=UTF-8"
${pkgs.coreutils}/bin/echo ""
${pkgs.coreutils}/bin/cat <<EOF
<!DOCTYPE html>
<html>
<head>
<meta name="color-scheme" content="light dark">
<style>
:root { color-scheme: light dark; }
body { font-family: sans-serif; line-height: 1.5; color: #000; background: #fff; max-width: 800px; margin: 0 auto; padding: 20px; }
h1 { border-bottom: 2px solid #000; color: #d97706; }
table { width: 100%; border-collapse: collapse; margin-bottom: 15px; font-size: 13px; }
th, td { text-align: left; padding: 6px; border-bottom: 1px solid #ddd; }
a { color: #0066cc; }
@media (prefers-color-scheme: dark) {
body { background: #121212; color: #eee; }
h1, th { border-color: #555; }
h1 { color: #f59e0b; }
th, td { border-color: #333; }
a { color: #66b3ff; }
}
</style>
</head>
<body>
<h1>SSH Login Alert</h1>
<p>A successful SSH login was just detected.</p>
<table>
<tr><th>User</th><td>$PAM_USER</td></tr>
<tr><th>Host</th><td>$HOSTNAME</td></tr>
<tr><th>Time</th><td>$TIMESTAMP</td></tr>
<tr><th>IP Address</th><td><a href="https://iplookup.flagfox.net/?ip=$PAM_RHOST">$PAM_RHOST</a></td></tr>
<tr><th>Service</th><td>$PAM_SERVICE</td></tr>
<tr><th>TTY</th><td>$PAM_TTY</td></tr>
</table>
</body>
</html>
EOF
) | /run/wrappers/bin/sendmail -f root@sachiel.schererleander.de leander@schererleander.de
fi
''}
''
);
};
}
|