use InetAddresses.forString instead of InetAddress.getByName because of DNS resolving

Author: tobiasholler

captchaservice-backend/pom.xml

@@ -318,6 +318,11 @@
             <artifactId>commons-net</artifactId>
             <version>3.11.1</version>
         </dependency>
+        <dependency>
+            <groupId>com.google.guava</groupId>
+            <artifactId>guava</artifactId>
+            <version>33.4.8-jre</version>
+        </dependency>
     </dependencies>
 
     <scm>

captchaservice-backend/src/main/java/de/muenchen/captchaservice/service/sourceaddress/SourceAddressService.java

@@ -1,5 +1,6 @@
 package de.muenchen.captchaservice.service.sourceaddress;
 
+import com.google.common.net.InetAddresses;
 import de.muenchen.captchaservice.configuration.captcha.CaptchaProperties;
 import de.muenchen.captchaservice.configuration.captcha.CaptchaSite;
 import de.muenchen.captchaservice.data.SourceAddress;
@@ -8,7 +9,6 @@
 import org.springframework.stereotype.Service;
 
 import java.net.InetAddress;
-import java.net.UnknownHostException;
 
 @Service
 @AllArgsConstructor
@@ -18,17 +18,13 @@ public class SourceAddressService {
     public SourceAddress parse(final String siteKey, final String sourceAddress) {
         CaptchaSite site = captchaProperties.sites().get(siteKey);
         String networkAddressString;
-        try {
-            InetAddress addr = InetAddress.getByName(sourceAddress);
-            if (addr instanceof java.net.Inet4Address) {
-                networkAddressString = NetworkAddressCalculator.getNetworkAddress(sourceAddress, site.sourceAddressIpv4Cidr());
-            } else if (addr instanceof java.net.Inet6Address) {
-                networkAddressString = NetworkAddressCalculator.getNetworkAddress(sourceAddress, site.sourceAddressIpv6Cidr());
-            } else {
-                throw new IllegalArgumentException("Unsupported IP address type: " + addr.getClass().getName());
-            }
-        } catch (UnknownHostException e) {
-            throw new IllegalArgumentException("Invalid IP address provided: " + sourceAddress, e);
+        InetAddress addr = InetAddresses.forString(sourceAddress);
+        if (addr instanceof java.net.Inet4Address) {
+            networkAddressString = NetworkAddressCalculator.getNetworkAddress(sourceAddress, site.sourceAddressIpv4Cidr());
+        } else if (addr instanceof java.net.Inet6Address) {
+            networkAddressString = NetworkAddressCalculator.getNetworkAddress(sourceAddress, site.sourceAddressIpv6Cidr());
+        } else {
+            throw new IllegalArgumentException("Unsupported IP address type: " + addr.getClass().getName());
         }
         return new SourceAddress(networkAddressString);
     }

captchaservice-backend/src/main/java/de/muenchen/captchaservice/util/networkaddresscalculator/NetworkAddressCalculator.java

@@ -1,5 +1,7 @@
 package de.muenchen.captchaservice.util.networkaddresscalculator;
 
+import com.google.common.net.InetAddresses;
+
 import java.net.InetAddress;
 import java.net.UnknownHostException;
 
@@ -17,7 +19,7 @@ public class NetworkAddressCalculator {
      */
     public static String getNetworkAddress(String address, int netSize) {
         try {
-            InetAddress inetAddress = InetAddress.getByName(address);
+            InetAddress inetAddress = InetAddresses.forString(address);
             byte[] addressBytes = inetAddress.getAddress();
             int addressLengthBits = addressBytes.length * 8;
 
@@ -45,8 +47,7 @@ public static String getNetworkAddress(String address, int netSize) {
 
             InetAddress netInetAddress = InetAddress.getByAddress(netAddressBytes);
             return netInetAddress.getHostAddress();
-
-        } catch (UnknownHostException e) {
+        } catch (IllegalArgumentException | UnknownHostException e) {
             throw new InvalidAddressException("Invalid address: " + address, address, e);
         }
     }

captchaservice-backend/src/main/java/de/muenchen/captchaservice/validation/SourceAddressConstraintValidator.java

@@ -1,17 +1,15 @@
 package de.muenchen.captchaservice.validation;
 
+import com.google.common.net.InetAddresses;
 import jakarta.validation.ConstraintValidator;
 import jakarta.validation.ConstraintValidatorContext;
 
-import java.net.InetAddress;
-import java.net.UnknownHostException;
-
 public class SourceAddressConstraintValidator implements ConstraintValidator<ValidSourceAddress, String> {
     @Override
     public boolean isValid(final String value, final ConstraintValidatorContext constraintValidatorContext) {
         try {
-            InetAddress.getByName(value);
-        } catch (UnknownHostException e) {
+            InetAddresses.forString(value);
+        } catch (IllegalArgumentException e) {
             return false;
         }
         return true;