From 56f08463781793651e53f236c46f88149570bbe9 Mon Sep 17 00:00:00 2001
From: Marc Alexander <admin@m-a-styles.de>
Date: Wed, 26 Jul 2023 17:21:43 +0200
Subject: [PATCH] [ticket/11765] Support IPv4 embedded IPv6 addresses in
 short_ipv6()

PHPBB3-11765
---
 phpBB/includes/functions.php         | 10 +++++-
 tests/functions/short_ipv6__test.php | 49 ++++++++++++++++++++++++++++
 2 files changed, 58 insertions(+), 1 deletion(-)
 create mode 100644 tests/functions/short_ipv6__test.php

diff --git a/phpBB/includes/functions.php b/phpBB/includes/functions.php
index 1234e1aa7b..e3ce50fe43 100644
--- a/phpBB/includes/functions.php
+++ b/phpBB/includes/functions.php
@@ -2918,7 +2918,7 @@ function get_censor_preg_expression($word)
 
 /**
 * Returns the first block of the specified IPv6 address and as many additional
-* ones as specified in the length paramater.
+* ones as specified in the length parameter.
 * If length is zero, then an empty string is returned.
 * If length is greater than 3 the complete IP will be returned
 */
@@ -2929,6 +2929,14 @@ function short_ipv6($ip, $length)
 		return '';
 	}
 
+	// Handle IPv4 embedded IPv6 addresses
+	if (preg_match('/(?:\d{1,3}\.){3}\d{1,3}$/i', $ip))
+	{
+		$binary_ip = inet_pton($ip);
+		$ip_v6 = $binary_ip ? inet_ntop($binary_ip) : $ip;
+		$ip = $ip_v6 ?: $ip;
+	}
+
 	// extend IPv6 addresses
 	$blocks = substr_count($ip, ':') + 1;
 	if ($blocks < 9)
diff --git a/tests/functions/short_ipv6__test.php b/tests/functions/short_ipv6__test.php
new file mode 100644
index 0000000000..8fa9cd7420
--- /dev/null
+++ b/tests/functions/short_ipv6__test.php
@@ -0,0 +1,49 @@
+<?php
+/**
+ *
+ * This file is part of the phpBB Forum Software package.
+ *
+ * @copyright (c) phpBB Limited <https://www.phpbb.com>
+ * @license GNU General Public License, version 2 (GPL-2.0)
+ *
+ * For full copyright and license information, please see
+ * the docs/CREDITS.txt file.
+ *
+ */
+
+class short_ipv6__test extends phpbb_test_case
+{
+	public function data_short_ipv6(): array
+	{
+		return [
+			['::1', 0, ''],
+			['::1', 1, '0000:0000'],
+			['::1', 2, '0000:0000:0000'],
+			['::1', 3, '0000:0000:0000:0000'],
+			['::1', 4, '0000:0000:0000:0000:0000:0000:0000:1'],
+			['2001:db8:3333:4444:5555:6666:7777:8888', 0, ''],
+			['2001:db8:3333:4444:5555:6666:7777:8888', 1, '2001:db8'],
+			['2001:db8:3333:4444:5555:6666:7777:8888', 2, '2001:db8:3333'],
+			['2001:db8:3333:4444:5555:6666:7777:8888', 3, '2001:db8:3333:4444'],
+			['2001:db8:3333:4444:5555:6666:7777:8888', 4, '2001:db8:3333:4444:5555:6666:7777:8888'],
+			['::ffff:192.168.1.1', 0, ''],
+			['::ffff:192.168.1.1', 1, '0000:0000'],
+			['::ffff:192.168.1.1', 2, '0000:0000:0000'],
+			['::ffff:192.168.1.1', 3, '0000:0000:0000:0000'],
+			['::ffff:192.168.1.1', 4, '0000:0000:0000:0000:0000:0000:ffff:192.168.1.1'],
+			['FADE:BAD::192.168.0.1', 0, ''],
+			['FADE:BAD::192.168.0.1', 1, 'fade:bad'],
+			['FADE:BAD::192.168.0.1', 2, 'fade:bad:0000'],
+			['FADE:BAD::192.168.0.1', 3, 'fade:bad:0000:0000'],
+			['FADE:BAD::192.168.0.1', 4, 'fade:bad:0000:0000:0000:0000:c0a8:1'],
+		];
+	}
+
+	/**
+	* @dataProvider data_short_ipv6
+	*/
+	public function test_short_ipv6($ip, $length, $expected)
+	{
+		$this->assertEquals($expected, short_ipv6($ip, $length));
+	}
+}