1 files changed, 106 insertions, 0 deletions
diff --git a/lib/private/Security/Normalizer/IpAddress.php b/lib/private/Security/Normalizer/IpAddress.php
new file mode 100644
index 00000000000..c44a5556678
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+++ b/lib/private/Security/Normalizer/IpAddress.php
@@ -0,0 +1,106 @@
+<?php
+/**
+ * @copyright Copyright (c) 2017 Lukas Reschke <lukas@statuscode.ch>
+ *
+ * @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 {
+	/** @var string */
+	private $ip;
+
+	/**
+	 * @param string $ip IP to normalized
+	 */
+	public function __construct($ip) {
+		$this->ip = $ip;
+	}
+
+	/**
+	 * Return the given subnet for an IPv4 address and mask bits
+	 *
+	 * @param string $ip
+	 * @param int $maskBits
+	 * @return string
+	 */
+	private function getIPv4Subnet($ip,
+								   $maskBits = 32) {
+		$binary = \inet_pton($ip);
+		for ($i = 32; $i > $maskBits; $i -= 8) {
+			$j = \intdiv($i, 8) - 1;
+			$k = (int) \min(8, $i - $maskBits);
+			$mask = (0xff - ((pow(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
+	 *
+	 * @param string $ip
+	 * @param int $maskBits
+	 * @return string
+	 */
+	private function getIPv6Subnet($ip, $maskBits = 48) {
+		$binary = \inet_pton($ip);
+		for ($i = 128; $i > $maskBits; $i -= 8) {
+			$j = \intdiv($i, 8) - 1;
+			$k = (int) \min(8, $i - $maskBits);
+			$mask = (0xff - ((pow(2, $k)) - 1));
+			$int = \unpack('C', $binary[$j]);
+			$binary[$j] = \pack('C', $int[1] & $mask);
+		}
+		return \inet_ntop($binary).'/'.$maskBits;
+	}
+
+	/**
+	 * Gets either the /32 (IPv4) or the /128 (IPv6) subnet of an IP address
+	 *
+	 * @return string
+	 */
+	public function getSubnet() {
+		if (\preg_match('/^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$/', $this->ip)) {
+			return $this->getIPv4Subnet(
+				$this->ip,
+				32
+			);
+		}
+		return $this->getIPv6Subnet(
+			$this->ip,
+			128
+		);
+	}
+
+	/**
+	 * Returns the specified IP address
+	 *
+	 * @return string
+	 */
+	public function __toString() {
+		return $this->ip;
+	}
+}