fix: strip trailing dots from hostnames and ips before validation

Signed-off-by: Robin Appelman <robin@icewind.nl>

Author: icewind1991

lib/private/Net/HostnameClassifier.php

@@ -38,6 +38,7 @@ class HostnameClassifier {
 	 * IP addresses are not considered local. Use the IpAddressClassifier for those.
 	 */
 	public function isLocalHostname(string $hostname): bool {
+		$hostname = rtrim($hostname, '.');
 		// Disallow local network top-level domains from RFC 6762
 		$topLevelDomain = substr((strrchr($hostname, '.') ?: ''), 1);
 		if (in_array($topLevelDomain, self::LOCAL_TOPLEVEL_DOMAINS)) {

lib/private/Net/IpAddressClassifier.php

@@ -70,6 +70,7 @@ public function getMappedIpv4(IPv6 $ip): ?IPv4 {
 	 * Hostnames are not considered local. Use the HostnameClassifier for those.
 	 */
 	public function isLocalAddress(string $ip): bool {
+		$ip = rtrim($ip, '.');
 		$parsedIp = Factory::parseAddressString(
 			$ip,
 			ParseStringFlag::IPV4_MAYBE_NON_DECIMAL | ParseStringFlag::IPV4ADDRESS_MAYBE_NON_QUAD_DOTTED | ParseStringFlag::MAY_INCLUDE_ZONEID

lib/private/Security/RemoteHostValidator.php

@@ -36,6 +36,8 @@ public function isValid(string $host): bool {
 			return true;
 		}
 
+		$host = rtrim($host, '.');
+
 		$host = idn_to_utf8(strtolower(urldecode($host)));
 		if ($host === false) {
 			return false;

tests/lib/Net/HostnameClassifierTest.php

@@ -30,6 +30,7 @@ public static function localHostnamesData(): array {
 			['another-host.local'],
 			['service.localhost'],
 			['randomdomain.internal'],
+			['another-host.local.'],
 		];
 	}
 
@@ -47,6 +48,7 @@ public static function publicHostnamesData(): array {
 			['example.org'],
 			['host.domain'],
 			['cloud.domain.tld'],
+			['cloud.domain.tld.'],
 		];
 	}