fix: IAM auth in CN RDS (#579)

src/main/protocol-impl/java/com/mysql/cj/protocol/a/authentication/AwsIamAuthenticationTokenHelper.java

@@ -31,6 +31,7 @@
 
 package com.mysql.cj.protocol.a.authentication;
 
+import com.mysql.cj.jdbc.ha.util.RdsUtils;
 import software.amazon.awssdk.auth.credentials.DefaultCredentialsProvider;
 import software.amazon.awssdk.regions.Region;
 import software.amazon.awssdk.services.rds.RdsUtilities;
@@ -50,7 +51,7 @@ public class AwsIamAuthenticationTokenHelper {
   private final String hostname;
   private final int port;
   private final Log log;
-  private static final int REGION_MATCHER_GROUP = 3;
+  private static final String REGION_MATCHER_GROUP = "region";
 
   public AwsIamAuthenticationTokenHelper(final String hostname, final int port, final String logger) {
     this.log = LogFactory.getLogger(logger, Log.LOGGER_INSTANCE_NAME);
@@ -83,23 +84,25 @@ private String generateAuthenticationToken(final String user) {
 
   private Region getRdsRegion() {
     // Check Hostname
-    final Pattern auroraDnsPattern =
-        Pattern.compile(
-            "(.+)\\.(proxy-|cluster-|cluster-ro-|cluster-custom-)?[a-zA-Z0-9]+\\.([a-zA-Z0-9\\-]+)\\.rds\\.amazonaws\\.com",
-            Pattern.CASE_INSENSITIVE);
-    final Matcher matcher = auroraDnsPattern.matcher(hostname);
+    Matcher matcher = RdsUtils.AURORA_DNS_PATTERN.matcher(hostname);
     if (!matcher.find()) {
-      // Does not match Amazon's Hostname, throw exception
-      final String exceptionMessage = Messages.getString(
-          "AuthenticationAwsIamPlugin.UnsupportedHostname",
-          new String[]{hostname});
-
-      log.logTrace(exceptionMessage);
-      throw ExceptionFactory.createException(exceptionMessage);
+      final Matcher chinaMatcher = RdsUtils.AURORA_CHINA_DNS_PATTERN.matcher(hostname);
+      if (!chinaMatcher.find()) {
+        // Does not match Amazon's Hostname, throw exception
+        final String exceptionMessage = Messages.getString(
+            "AuthenticationAwsIamPlugin.UnsupportedHostname",
+            new String[]{hostname});
+
+        log.logTrace(exceptionMessage);
+        throw ExceptionFactory.createException(exceptionMessage);
+      }
+      matcher = chinaMatcher;
     }
 
     // Get Region
-    final String rdsRegion = matcher.group(REGION_MATCHER_GROUP);
+    final String rdsRegion = matcher.group(REGION_MATCHER_GROUP) == null
+        ? null
+        : matcher.group(REGION_MATCHER_GROUP).replaceAll("rds", "").replaceAll("\\.", "");
 
     // Check Region
     Optional<Region> regionOptional = Region.regions().stream()

src/main/resources/com/mysql/cj/LocalizedErrorMessages.properties

@@ -69,7 +69,7 @@ AuthenticationProvider.BadDisabledAuthenticationPlugin=Can''t disable the defaul
 AuthenticationProvider.AuthenticationPluginRequiresSSL=SSL connection required for plugin "{0}". Check if ''sslMode'' is enabled.
 AuthenticationProvider.UnexpectedAuthenticationApproval=Unexpected authentication approval. Authentication plugin "{0}" did not report "done" state but server has approved the connection.
 
-AuthenticationAwsIamPlugin.UnsupportedHostname=Unsupported AWS hostname ''{0}''. Amazon domain name in format *.AWS-Region.rds.amazonaws.com is expected
+AuthenticationAwsIamPlugin.UnsupportedHostname=Unsupported AWS hostname ''{0}''. Amazon domain name in format *.AWS-Region.rds.amazonaws.com or *.rds.AWS-Region.amazonaws.com.cn is expected
 AuthenticationAwsIamPlugin.UnsupportedRegion=Unsupported AWS region ''{0}''. For supported regions, please read https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concepts.RegionsAndAvailabilityZones.html
 AuthenticationAwsIamPlugin.MissingSDK=Unable to connect using AWS IAM authentication due to missing AWS Java SDK For Amazon RDS. Add dependency to classpath.
 

src/main/user-impl/java/com/mysql/cj/jdbc/ha/util/RdsUtils.java

@@ -77,7 +77,7 @@ public class RdsUtils {
   // Instance Endpoint: <instance-name>.<xyz>.rds.<aws-region>.amazonaws.com.cn
   // Example: test-postgres-instance-1.123456789012.rds.cn-northwest-1.amazonaws.com.cn
 
-  private static final Pattern AURORA_DNS_PATTERN =
+  public static final Pattern AURORA_DNS_PATTERN =
       Pattern.compile(
           "(?<instance>.+)\\."
               + "(?<dns>proxy-|cluster-|cluster-ro-|cluster-custom-)?"
@@ -104,7 +104,7 @@ public class RdsUtils {
               + "(?<domain>[a-zA-Z0-9]+\\.(?<region>[a-zA-Z0-9\\-]+)\\.rds\\.amazonaws\\.com(\\.cn)?)",
           Pattern.CASE_INSENSITIVE);
 
-  private static final Pattern AURORA_CHINA_DNS_PATTERN =
+  public static final Pattern AURORA_CHINA_DNS_PATTERN =
       Pattern.compile(
           "(?<instance>.+)\\."
               + "(?<dns>proxy-|cluster-|cluster-ro-|cluster-custom-)?"

src/test/java/testsuite/simple/AwsIamAuthenticationHelperTest.java

@@ -51,6 +51,18 @@ public void test_1_ValidHostAndRegion() {
             PORT,
             StandardLogger.class.getName()
         ));
+
+        Assertions.assertNotNull(new AwsIamAuthenticationTokenHelper(
+            "MyDBInstanceName.SomeServerName.us-east-1.rds.amazonaws.com.cn",
+            PORT,
+            StandardLogger.class.getName()
+        ));
+
+        Assertions.assertNotNull(new AwsIamAuthenticationTokenHelper(
+            "test-postgres.cluster-123456789012.rds.cn-northwest-1.amazonaws.com.cn",
+            PORT,
+            StandardLogger.class.getName()
+        ));
     }