fix(32bit): make pack compatible with 32bit PHP

The `P` formatter is 64bit only - we need to manually pack the 64bit.

Signed-off-by: Ferdinand Thiessen <opensource@fthiessen.de>

Author: susnux

lib/private/Security/Normalizer/IpAddress.php

@@ -41,10 +41,14 @@ private function getIPv6Subnet(string $ip): string {
 		$config = \OCP\Server::get(IConfig::class);
 		$maskSize = min(64, $config->getSystemValueInt('security.ipv6_normalized_subnet_size', 56));
 		$maskSize = max(32, $maskSize);
-		$mask = pack('VVP', (1 << 32) - 1, (1 << $maskSize - 32) - 1, 0);
+		if (PHP_INT_SIZE === 4) {
+			// as long as we support 32bit PHP we cannot use the `P` pack formatter (and not overflow 32bit integer)
+			$mask = pack('VVVV', 0xFFFF, $maskSize === 64 ? 0xFFFF : ((1 << $maskSize - 32) - 1), 0, 0);
+		} else {
+			$mask = pack('VVP', (1 << 32) - 1, (1 << $maskSize - 32) - 1, 0);
+		}
 
 		$binary = \inet_pton($ip);
-
 		return inet_ntop($binary & $mask) . '/' . $maskSize;
 	}