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Merge pull request #33353 from nextcloud/backport/33031/stable24
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[stable24] Improve local IP detection
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blizzz authored Aug 2, 2022
2 parents 66d4f67 + 38eb0df commit 039fd75
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Showing 5 changed files with 206 additions and 2 deletions.
1 change: 1 addition & 0 deletions lib/composer/composer/autoload_classmap.php
Original file line number Diff line number Diff line change
Expand Up @@ -1251,6 +1251,7 @@
'OC\\Http\\Client\\NegativeDnsCache' => $baseDir . '/lib/private/Http/Client/NegativeDnsCache.php',
'OC\\Http\\Client\\Response' => $baseDir . '/lib/private/Http/Client/Response.php',
'OC\\Http\\CookieHelper' => $baseDir . '/lib/private/Http/CookieHelper.php',
'OC\\Http\\IpUtils' => $baseDir . '/lib/private/Http/IpUtils.php',
'OC\\Http\\WellKnown\\RequestManager' => $baseDir . '/lib/private/Http/WellKnown/RequestManager.php',
'OC\\InitialStateService' => $baseDir . '/lib/private/InitialStateService.php',
'OC\\Installer' => $baseDir . '/lib/private/Installer.php',
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1 change: 1 addition & 0 deletions lib/composer/composer/autoload_static.php
Original file line number Diff line number Diff line change
Expand Up @@ -1280,6 +1280,7 @@ class ComposerStaticInit53792487c5a8370acc0b06b1a864ff4c
'OC\\Http\\Client\\NegativeDnsCache' => __DIR__ . '/../../..' . '/lib/private/Http/Client/NegativeDnsCache.php',
'OC\\Http\\Client\\Response' => __DIR__ . '/../../..' . '/lib/private/Http/Client/Response.php',
'OC\\Http\\CookieHelper' => __DIR__ . '/../../..' . '/lib/private/Http/CookieHelper.php',
'OC\\Http\\IpUtils' => __DIR__ . '/../../..' . '/lib/private/Http/IpUtils.php',
'OC\\Http\\WellKnown\\RequestManager' => __DIR__ . '/../../..' . '/lib/private/Http/WellKnown/RequestManager.php',
'OC\\InitialStateService' => __DIR__ . '/../../..' . '/lib/private/InitialStateService.php',
'OC\\Installer' => __DIR__ . '/../../..' . '/lib/private/Installer.php',
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16 changes: 14 additions & 2 deletions lib/private/Http/Client/LocalAddressChecker.php
Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,7 @@

use OCP\Http\Client\LocalServerException;
use Psr\Log\LoggerInterface;
use OC\Http\IpUtils;

class LocalAddressChecker {
private LoggerInterface $logger;
Expand All @@ -36,7 +37,16 @@ public function __construct(LoggerInterface $logger) {
}

public function ThrowIfLocalIp(string $ip) : void {
if ((bool)filter_var($ip, FILTER_VALIDATE_IP) && !filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE)) {
$localRanges = [
'100.64.0.0/10', // See RFC 6598
'192.0.0.0/24', // See RFC 6890
];
if (
(bool)filter_var($ip, FILTER_VALIDATE_IP) &&
(
!filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE) ||
IpUtils::checkIp($ip, $localRanges)
)) {
$this->logger->warning("Host $ip was not connected to because it violates local access rules");
throw new LocalServerException('Host violates local access rules');
}
Expand All @@ -46,7 +56,9 @@ public function ThrowIfLocalIp(string $ip) : void {
$delimiter = strrpos($ip, ':'); // Get last colon
$ipv4Address = substr($ip, $delimiter + 1);

if (!filter_var($ipv4Address, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE)) {
if (
!filter_var($ipv4Address, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE) ||
IpUtils::checkIp($ip, $localRanges)) {
$this->logger->warning("Host $ip was not connected to because it violates local access rules");
throw new LocalServerException('Host violates local access rules');
}
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185 changes: 185 additions & 0 deletions lib/private/Http/IpUtils.php
Original file line number Diff line number Diff line change
@@ -0,0 +1,185 @@
<?php

/*
* This file comes from Symfony. Copied here to avoid backporting a new dependency.
*
* (c) Fabien Potencier <fabien@symfony.com>
*
* SPDX-License-Identifier: MIT
*/

namespace OC\Http;

/**
* Http utility functions.
*
* @author Fabien Potencier <fabien@symfony.com>
*/
class IpUtils {
/**
* @var array<string,bool>
*/
private static $checkedIps = [];

/**
* This class should not be instantiated.
*/
private function __construct() {
}

/**
* Checks if an IPv4 or IPv6 address is contained in the list of given IPs or subnets.
*
* @param string|array $ips List of IPs or subnets (can be a string if only a single one)
*
* @return bool
*/
public static function checkIp(string $requestIp, $ips) {
if (!\is_array($ips)) {
$ips = [$ips];
}

$method = substr_count($requestIp, ':') > 1 ? 'checkIp6' : 'checkIp4';

foreach ($ips as $ip) {
if (self::$method($requestIp, $ip)) {
return true;
}
}

return false;
}

/**
* Compares two IPv4 addresses.
* In case a subnet is given, it checks if it contains the request IP.
*
* @param string $ip IPv4 address or subnet in CIDR notation
*
* @return bool Whether the request IP matches the IP, or whether the request IP is within the CIDR subnet
*/
public static function checkIp4(string $requestIp, string $ip) {
$cacheKey = $requestIp.'-'.$ip;
if (isset(self::$checkedIps[$cacheKey])) {
return self::$checkedIps[$cacheKey];
}

if (!filter_var($requestIp, \FILTER_VALIDATE_IP, \FILTER_FLAG_IPV4)) {
return self::$checkedIps[$cacheKey] = false;
}

if (str_contains($ip, '/')) {
[$address, $netmask] = explode('/', $ip, 2);

if ('0' === $netmask) {
return self::$checkedIps[$cacheKey] = (bool)filter_var($address, \FILTER_VALIDATE_IP, \FILTER_FLAG_IPV4);
}

$netmask = (int)$netmask;

if ($netmask < 0 || $netmask > 32) {
return self::$checkedIps[$cacheKey] = false;
}
} else {
$address = $ip;
$netmask = 32;
}

if (false === ip2long($address)) {
return self::$checkedIps[$cacheKey] = false;
}

return self::$checkedIps[$cacheKey] = 0 === substr_compare(sprintf('%032b', ip2long($requestIp)), sprintf('%032b', ip2long($address)), 0, $netmask);
}

/**
* Compares two IPv6 addresses.
* In case a subnet is given, it checks if it contains the request IP.
*
* @author David Soria Parra <dsp at php dot net>
*
* @see https://github.com/dsp/v6tools
*
* @param string $ip IPv6 address or subnet in CIDR notation
*
* @return bool
*
* @throws \RuntimeException When IPV6 support is not enabled
*/
public static function checkIp6(string $requestIp, string $ip) {
$cacheKey = $requestIp.'-'.$ip;
if (isset(self::$checkedIps[$cacheKey])) {
return self::$checkedIps[$cacheKey];
}

if (!((\extension_loaded('sockets') && \defined('AF_INET6')) || @inet_pton('::1'))) {
throw new \RuntimeException('Unable to check Ipv6. Check that PHP was not compiled with option "disable-ipv6".');
}

if (str_contains($ip, '/')) {
[$address, $netmask] = explode('/', $ip, 2);

if ('0' === $netmask) {
return (bool) unpack('n*', @inet_pton($address));
}

$netmask = (int)$netmask;

if ($netmask < 1 || $netmask > 128) {
return self::$checkedIps[$cacheKey] = false;
}
} else {
$address = $ip;
$netmask = 128;
}

$bytesAddr = unpack('n*', @inet_pton($address));
$bytesTest = unpack('n*', @inet_pton($requestIp));

if (!$bytesAddr || !$bytesTest) {
return self::$checkedIps[$cacheKey] = false;
}

for ($i = 1, $ceil = ceil($netmask / 16); $i <= $ceil; ++$i) {
$left = $netmask - 16 * ($i - 1);
$left = ($left <= 16) ? $left : 16;
$mask = ~(0xFFFF >> $left) & 0xFFFF;
if (($bytesAddr[$i] & $mask) != ($bytesTest[$i] & $mask)) {
return self::$checkedIps[$cacheKey] = false;
}
}

return self::$checkedIps[$cacheKey] = true;
}

/**
* Anonymizes an IP/IPv6.
*
* Removes the last byte for v4 and the last 8 bytes for v6 IPs
*/
public static function anonymize(string $ip): string {
$wrappedIPv6 = false;
if ('[' === substr($ip, 0, 1) && ']' === substr($ip, -1, 1)) {
$wrappedIPv6 = true;
$ip = substr($ip, 1, -1);
}

$packedAddress = inet_pton($ip);
if (4 === \strlen($packedAddress)) {
$mask = '255.255.255.0';
} elseif ($ip === inet_ntop($packedAddress & inet_pton('::ffff:ffff:ffff'))) {
$mask = '::ffff:ffff:ff00';
} elseif ($ip === inet_ntop($packedAddress & inet_pton('::ffff:ffff'))) {
$mask = '::ffff:ff00';
} else {
$mask = 'ffff:ffff:ffff:ffff:0000:0000:0000:0000';
}
$ip = inet_ntop($packedAddress & inet_pton($mask));

if ($wrappedIPv6) {
$ip = '['.$ip.']';
}

return $ip;
}
}
5 changes: 5 additions & 0 deletions tests/lib/Http/Client/LocalAddressCheckerTest.php
Original file line number Diff line number Diff line change
Expand Up @@ -96,6 +96,8 @@ public function dataInternalIPs() : array {
['10.0.0.1'],
['::'],
['::1'],
['100.100.100.200'],
['192.0.0.1'],
];
}

Expand All @@ -116,6 +118,9 @@ public function dataPreventLocalAddress():array {
['another-host.local'],
['service.localhost'],
['!@#$'], // test invalid url
['100.100.100.200'],
['192.0.0.1'],
['randomdomain.internal'],
];
}

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