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<?php
declare(strict_types=1);
/**
* @copyright Copyright (c) 2017 Lukas Reschke <lukas@statuscode.ch>
*
* @author Christoph Wurst <christoph@winzerhof-wurst.at>
* @author Konrad Bucheli <kb@open.ch>
* @author Lukas Reschke <lukas@statuscode.ch>
* @author Morris Jobke <hey@morrisjobke.de>
* @author Roeland Jago Douma <roeland@famdouma.nl>
* @author Thomas Citharel <nextcloud@tcit.fr>
*
* @license GNU AGPL version 3 or any later version
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
namespace OC\Security\Normalizer;
/**
* Class IpAddress is used for normalizing IPv4 and IPv6 addresses in security
* relevant contexts in Nextcloud.
*
* @package OC\Security\Normalizer
*/
class IpAddress {
/**
* @param string $ip IP to normalized
*/
public function __construct(
private string $ip,
) {
}
/**
* Return the given subnet for an IPv4 address and mask bits
*/
private function getIPv4Subnet(string $ip, int $maskBits = 32): string {
$binary = \inet_pton($ip);
for ($i = 32; $i > $maskBits; $i -= 8) {
$j = \intdiv($i, 8) - 1;
$k = \min(8, $i - $maskBits);
$mask = (0xff - ((2 ** $k) - 1));
$int = \unpack('C', $binary[$j]);
$binary[$j] = \pack('C', $int[1] & $mask);
}
return \inet_ntop($binary).'/'.$maskBits;
}
/**
* Return the given subnet for an IPv6 address and mask bits
*/
private function getIPv6Subnet(string $ip, int $maskBits = 48): string {
if ($ip[0] === '[' && $ip[-1] === ']') { // If IP is with brackets, for example [::1]
$ip = substr($ip, 1, strlen($ip) - 2);
}
$pos = strpos($ip, '%'); // if there is an explicit interface added to the IP, e.g. fe80::ae2d:d1e7:fe1e:9a8d%enp2s0
if ($pos !== false) {
$ip = substr($ip, 0, $pos - 1);
}
$binary = \inet_pton($ip);
for ($i = 128; $i > $maskBits; $i -= 8) {
$j = \intdiv($i, 8) - 1;
$k = \min(8, $i - $maskBits);
$mask = (0xff - ((2 ** $k) - 1));
$int = \unpack('C', $binary[$j]);
$binary[$j] = \pack('C', $int[1] & $mask);
}
return \inet_ntop($binary).'/'.$maskBits;
}
/**
* Returns the IPv4 address embedded in an IPv6 if applicable.
* The detected format is "::ffff:x.x.x.x" using the binary form.
*
* @return string|null embedded IPv4 string or null if none was found
*/
private function getEmbeddedIpv4(string $ipv6): ?string {
$binary = inet_pton($ipv6);
if (!$binary) {
return null;
}
for ($i = 0; $i <= 9; $i++) {
if (unpack('C', $binary[$i])[1] !== 0) {
return null;
}
}
for ($i = 10; $i <= 11; $i++) {
if (unpack('C', $binary[$i])[1] !== 255) {
return null;
}
}
$binary4 = '';
for ($i = 12; $i < 16; $i++) {
$binary4 .= $binary[$i];
}
return inet_ntop($binary4);
}
/**
* Gets either the /32 (IPv4) or the /64 (IPv6) subnet of an IP address
*/
public function getSubnet(): string {
if (\preg_match('/^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$/', $this->ip)) {
return $this->getIPv4Subnet(
$this->ip,
32
);
}
$ipv4 = $this->getEmbeddedIpv4($this->ip);
if ($ipv4 !== null) {
return $this->getIPv4Subnet(
$ipv4,
32
);
}
return $this->getIPv6Subnet(
$this->ip,
64
);
}
/**
* Returns the specified IP address
*/
public function __toString(): string {
return $this->ip;
}
}
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