Fix a bug in DefaultHostnameVerifier wildcard handling.

Wildcard domain name patterns of the form *.remainder are supposed to
match domain names that exactly match the remainder. Due to a bug,
the match was not exact but rather a prefix match: domain names
starting with the remainder would match too.

This CL fixes the issue.

Bug: 18432707
Change-Id: Ic2fccbfeac4f5d6e71b49ecbd36c248214baebad

Author: Alex Klyubin

luni/src/main/java/javax/net/ssl/DefaultHostnameVerifier.java

@@ -137,7 +137,7 @@ public boolean verifyHostName(String hostName, String cn) {
             return hostName.equals(cn);
         }
 
-        if (cn.startsWith("*.") && hostName.regionMatches(0, cn, 2, cn.length() - 2)) {
+        if (cn.startsWith("*.") && hostName.equals(cn.substring(2))) {
             return true; // "*.foo.com" matches "foo.com"
         }
 

luni/src/test/java/libcore/javax/net/ssl/DefaultHostnameVerifierTest.java

@@ -114,15 +114,18 @@ public void testUnknownSubjectAltName() {
     public void testWildcardMatchesWildcardSuffix() {
         assertTrue(verifier.verifyHostName("b.c.d", "*.b.c.d"));
         assertTrue(verifier.verifyHostName("imap.google.com", "*.imap.google.com"));
+        assertFalse(verifier.verifyHostName("imap.google.com.au", "*.imap.google.com"));
     }
 
     public void testWildcardMatchingSubstring() {
         assertTrue(verifier.verifyHostName("b.c.d", "b*.c.d"));
         assertTrue(verifier.verifyHostName("imap.google.com", "ima*.google.com"));
+        assertFalse(verifier.verifyHostName("imap.google.com.au", "ima*.google.com"));
     }
 
     public void testWildcardMatchingEmptySubstring() {
         assertTrue(verifier.verifyHostName("imap.google.com", "imap*.google.com"));
+        assertFalse(verifier.verifyHostName("imap.google.com.au", "imap*.google.com"));
     }
 
     public void testWildcardMatchesChildDomain() {