Address comments

netty · Jul 19, 2023 · 4b30188 · 4b30188
1 parent 08eb636
commit 4b30188
Showing 1 changed file with 10 additions and 5 deletions.
diff --git a/handler/src/main/java/io/netty/handler/ssl/EnhancingX509ExtendedTrustManager.java b/handler/src/main/java/io/netty/handler/ssl/EnhancingX509ExtendedTrustManager.java
@@ -24,6 +24,7 @@
 import java.net.Socket;
 import java.security.cert.CertificateException;
 import java.security.cert.X509Certificate;
+import java.util.Collection;
 import java.util.List;
 
 
@@ -100,18 +101,22 @@ private static void throwEnhancedCertificateException(X509Certificate[] chain, C
             StringBuilder names = new StringBuilder(64);
             for (int i = 0; i < chain.length; i++) {
                 X509Certificate cert = chain[i];
-                for (List<?> altNames : cert.getSubjectAlternativeNames()) {
-                    // 2 is dNSName. See X509Certificate javadocs.
-                    if (altNames.size() >= 2 && ((Integer) altNames.get(0)) == 2) {
-                        names.append((String) altNames.get(1)).append(",");
+                Collection<List<?>> collection = cert.getSubjectAlternativeNames();
+                if (collection != null) {
+                    for (List<?> altNames : collection) {
+                        // 2 is dNSName. See X509Certificate javadocs.
+                        if (altNames.size() >= 2 && ((Integer) altNames.get(0)).intValue() == 2) {
+                            names.append((String) altNames.get(1)).append(",");
+                        }
                     }
                 }
             }
             if (names.length() != 0) {
                 // Strip of ,
                 names.setLength(names.length() - 1);
                 throw new CertificateException(message +
-                        " Subject alternative DNS names in the certificate chain: " + names, e);
+                        " Subject alternative DNS names in the certificate chain of " + chain.length +
+                        " certificate(s): " + names, e);
             }
         }
         throw e;