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<!DOCTYPE html>
<html>
<head>
<title>BlaDNS</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body>
<?php
ini_set("display_errors", 1);
ini_set("display_startup_errors", 1);
error_reporting(E_ALL);
define("ZONEROOT", "/var/bind/pri/");
define("ZONESUFFIX", ".zone");
function incrementserial($zonetext) {
$serial = array("");
$newserial = "";
// See if we can detect a serial number
if (preg_match("/\(($|^|[[:space:]])*[0-9]{10}([[:space:]]|;|$|^)+/", $zonetext, $matches)) {;
// Only bother with the first match
preg_match("/[0-9]{10}/", $matches[0], $serial);
$today = date("Ymd00");
if ($serial[0] < $today) {
$newserial = $today;
} else {
$newserial = $serial[0] + 1;
}
// The effort below is gone to to avoid replacing more than one match with our *one* new serial number
// Prepare a string to replace the string we found the serial in
$rebuiltstring = str_replace($serial[0], $newserial, $matches[0]);
// Escape special regex characters since we need to use preg_replace below to limit to one replacement
$escapedmatch = preg_quote($matches[0]);
$zonetext = preg_replace("/" . $escapedmatch . "/", $rebuiltstring, $zonetext, 1);
}
return array($zonetext, $serial[0], $newserial);
}
function sshrun($command) {
$host = "misc.tghost.co.uk";
$user = "bladns.net";
$keypub = "/home/bladns.net/.ssh/id_rsa.pub";
$keypriv = "/home/bladns.net/.ssh/id_rsa";
$connection = ssh2_connect($host, 22, array("hostkey" => "ssh-rsa"));
ssh2_auth_pubkey_file($connection, $user, $keypub, $keypriv);
$stream = ssh2_exec($connection, $command);
stream_set_blocking($stream, true);
$stream_out = ssh2_fetch_stream($stream, SSH2_STREAM_STDIO);
return stream_get_contents($stream_out);
}
function getzone($domain, $password = null) {
if (!preg_match('/^[0-9A-Za-z\.\-]*$/', $domain)) {
die("invalid domain");
}
$string = sshrun("cat " . ZONEROOT . $domain . ZONESUFFIX);
$zonelines = explode("\n", $string);
$zonehash = explode(" ", $zonelines[0]);
// Not all calls to this function need a password
if (!$password) {
return $string;
} else if (strtolower($zonehash[sizeof($zonehash) - 1]) == strtolower($password)) {
return $string;
} else {
return;
}
}
function writezone($domain, $zonetext, $password = null) {
if (!preg_match('/^[0-9A-Za-z\.\-]*$/', $domain)) {
die("invalid domain");
}
// Not all calls to this function need a password. If passwords are in use,
// check to make sure it is correct.
if ($password && !getzone($domain, $password)) {
die("somehow the password went bad");
}
$zonetext = str_replace('$', '\$', $zonetext);
sshrun("echo -en \"$zonetext\" > " . ZONEROOT . "$domain" . ZONESUFFIX);
sshrun("rndc reload $domain");
}
// Main entry point
if (isset($_GET['mode']) && isset($_GET['zone']) && isset($_GET['hash'])) {
// Some sort of mode (at the moment only "update" is supported
if ($_GET['mode'] == "update") {
// An auto update is being requested. This is where one or more zone records
// are requested to be updated to the requester's IP address.
$zonetext = getzone($_GET['zone']);
// Only use \n for newlines
$zonetext = str_replace("\r", "", $zonetext);
// Split into individual lines
$zonelines = explode("\n", $zonetext);
$matches = array();
// Find lines that ended with the hash provided (if any)
$i = 0;
foreach ($zonelines as $line) {
if (preg_match("/" . $_GET['hash'] . "$/", $line)) {
array_push($matches, array($i, $line));
}
$i++;
}
// Go through the lines that matched the hash and see if we can find an update to do
foreach ($matches as $arrline) {
$line = $arrline[1];
// Get rid of the comment
$exploded = explode(";", $line);
$record = $exploded[0];
// Split into individual components
$parts = preg_split("/\s+/", $record);
// Make sure the last element isn't blank (would happen if the comment had a space before it)
while ($parts[sizeof($parts) - 1] == "") {
array_pop($parts);
}
// See if the record type on this line matches the request address type (e.g. an A record update must be requested by an IPv4 address)
if ($parts[sizeof($parts) - 2] == "A") {
// Regex for IPv4 address
if (preg_match("/\b((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)(\.|$)){4}\b/", $_SERVER['REMOTE_ADDR'])) {
$parts[sizeof($parts) - 1] = $_SERVER['REMOTE_ADDR'];
} else {
die("A record and non-IPv4 request - bad.");
}
} else if ($parts[sizeof($parts) - 2] == "AAAA") {
// Regex for IPv6 address
if (preg_match("/(([0-9a-fA-F]{1,4}:){7,7}[0-9a-fA-F]{1,4}|([0-9a-fA-F]{1,4}:){1,7}:|([0-9a-fA-F]{1,4}:){1,6}:[0-9a-fA-F]{1,4}|([0-9a-fA-F]{1,4}:){1,5}(:[0-9a-fA-F]{1,4}){1,2}|([0-9a-fA-F]{1,4}:){1,4}(:[0-9a-fA-F]{1,4}){1,3}|([0-9a-fA-F]{1,4}:){1,3}(:[0-9a-fA-F]{1,4}){1,4}|([0-9a-fA-F]{1,4}:){1,2}(:[0-9a-fA-F]{1,4}){1,5}|[0-9a-fA-F]{1,4}:((:[0-9a-fA-F]{1,4}){1,6})|:((:[0-9a-fA-F]{1,4}){1,7}|:)|fe80:(:[0-9a-fA-F]{0,4}){0,4}%[0-9a-zA-Z]{1,}|::(ffff(:0{1,4}){0,1}:){0,1}((25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9])\.){3,3}(25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9])|([0-9a-fA-F]{1,4}:){1,4}:((25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9])\.){3,3}(25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9]))/", $_SERVER['REMOTE_ADDR'])) {
$parts[sizeof($parts) - 1] = $_SERVER['REMOTE_ADDR'];
} else {
die("AAAA record and non-IPv6 request - bad.");
}
} else {
die("Unrecognised record type!");
}
// Update original zone file array with the new line at the correct position
$zonelines[$arrline[0]] = preg_replace("/[A-Za-z0-9:\.]+([[:space:]]*;)/", $parts[sizeof($parts) - 1] . "$1", $line);
}
// Next we need to turn the zone file array back into a string again
$newzonetext = "";
// If the last element was blank, remove it since we'll add a new blank ourselves
if ($zonelines[sizeof($zonelines) - 1] == "") {
array_pop($zonelines);
}
// Do the actual converstion to string
foreach ($zonelines as $line) {
$newzonetext .= $line . "\n";
}
// See if there was actually a change as a result of this request...
if ($zonetext == $newzonetext) {
// ...if not, abandon ship
echo "<p>no changes detected :)</p>";
} else {
// ...if so, increment the serial number and...
$newzonetext = incrementserial($newzonetext)[0];
// ...finally write the zone with the updated record(s)
writezone($_GET['zone'], $newzonetext);
echo "<p>record(s) updated :)</p>";
}
}
} else if (isset($_POST['domain']) && isset($_POST['password']) && !isset($_POST['zonetext'])) {
if (!preg_match('/^[0-9A-Za-z\.\-]*$/', $_POST['domain'])) {
die("invalid domain");
}
$password = hash("sha256", $_POST['password']);
if ($zonefile = getzone($_POST['domain'], $password)) {
?>
<p>1. Your zonefile is below.</p>
<p>2. Ensure the first line always ends with a SHA-256 hash of your chosen password.</p>
<p>3. To automatically update a particular record, give the line a comment ending with a secret ID (e.g. a SHA-256 hash), e.g.:</p>
<pre>
test 300 IN A 192.168.0.1 ; sha256 = 7f480e744a79953eb916b68f540e0eeec6f9cf23edf4aa08cc1cdf5f077c0f6f
test 300 IN AAAA ::1 ; sha256 = b493d48364afe44d11c0165cf470a4164d1e2609911ef998be868d46ade3de4e
</pre>
<p>And then do an HTTP(S) request to:</p>
<pre>https://bladns.net/dns.php?mode=update&zone=<strong>yourdomain.tld</strong>&hash=<strong>yourid</strong></pre>
<p>Your record will be updated with the IP you did the request from.</p>
<form action="dns.php" method="post">
<textarea rows="24" cols="80" name="zonetext" autofocus><?php echo $zonefile; ?></textarea><br>
<?php
$arrincrement = incrementserial($zonefile);
if ($arrincrement[0] != $zonefile) {
?>
<input type="checkbox" name="increment" checked>Automatically increment serial number from <?php echo $arrincrement[1] . " to " . $arrincrement[2]; ?>?</input><br>
<?php
}
?>
<input type="hidden" name="domain" value="<?php echo $_POST['domain']; ?>">
<input type="hidden" name="password" value="<?php echo $password; ?>">
<input type="submit" value="Update zonefile"><br>
</form>
<?php
} else {
echo "<p>sorry, the domain or password is wrong :(</p>";
}
} else if (isset($_POST['domain']) && isset($_POST['password']) && isset($_POST['zonetext'])) {
$zonetext = str_replace("\r", '', $_POST['zonetext']);
// Increment the serial number if the box was checked
if (isset($_POST['increment'])) {
$zonetext = incrementserial($zonetext)[0];
}
writezone($_POST['domain'], $zonetext, $_POST['password']);
echo "<p>all done :)</p>";
} else {
?>
<form name="login" action="dns.php" method="post">
Domain name: <input type="text" name="domain" autofocus><br>
Password: <input type="password" name="password"><br>
<input type="submit" value="Login">
</form>
<?php
}
?>
</body>
</html>
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