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Simplify IP address normalizer with IP masks #39582

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Merged
Altahrim merged 1 commit into from
Nov 9, 2023
Merged

Simplify IP address normalizer with IP masks #39582

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69 changes: 15 additions & 54 deletions lib/private/Security/Normalizer/IpAddress.php
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Original file line number Diff line number Diff line change
Expand Up @@ -38,48 +38,29 @@
*/
class IpAddress {
/**
* @param string $ip IP to normalized
* @param string $ip IP to normalize
*/
public function __construct(
private string $ip,
) {
}

/**
* Return the given subnet for an IPv4 address and mask bits
* Return the given subnet for an IPv6 address (64 first 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 {
private function getIPv6Subnet(string $ip): string {
if ($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;
$mask = inet_pton('FFFF:FFFF:FFFF:FFFF::');

return inet_ntop($binary & $mask).'/64';
}

/**
Expand All @@ -93,50 +74,30 @@ private function getEmbeddedIpv4(string $ipv6): ?string {
if (!$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];
$mask = inet_pton('::FFFF:FFFF');
if (($binary & ~$mask) !== inet_pton('::FFFF:0.0.0.0')) {
return null;
}

return inet_ntop($binary4);
return inet_ntop(substr($binary, -4));
}


/**
* 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(
$this->ip,
32
);
if (filter_var($this->ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4)) {
return $this->ip.'/32';
}

$ipv4 = $this->getEmbeddedIpv4($this->ip);
if ($ipv4 !== null) {
return $this->getIPv4Subnet(
$ipv4,
32
);
return $ipv4.'/32';
}

return $this->getIPv6Subnet(
$this->ip,
64
);
return $this->getIPv6Subnet($this->ip);
}

/**
Expand Down