[fix] OpenSSL::Cipher#iv_len for ECB (#169)

Author: kares

src/main/java/org/jruby/ext/openssl/Cipher.java

@@ -614,7 +614,11 @@ public int getIvLength() {
             getKeyLength();
 
             if ( ivLength == -1 ) {
-                if ( "AES".equals(base) ) {
+                // ECB mode does not use an IV, so check this first
+                if ( "ECB".equals(mode) ) {
+                    ivLength = 0;
+                }
+                else if ( "AES".equals(base) ) {
                     ivLength = 16; // OpenSSL defaults to 12
                     // NOTE: we can NOT handle 12 for non GCM mode
                     if ( "GCM".equals(mode) || "CCM".equals(mode) ) ivLength = 12;
@@ -625,9 +629,6 @@ public int getIvLength() {
                 //else if ( "RC4".equals(base) ) {
                 //    ivLength = 8;
                 //}
-                else if ( "ECB".equals(mode) ) {
-                    ivLength = 0;
-                }
                 else {
                     ivLength = 8;
                 }

src/test/ruby/test_cipher.rb

@@ -126,6 +126,17 @@ def test_des_iv_len
     assert_equal 8, cipher.iv_len
   end
 
+  def test_aes_ecb_iv_len
+    # ECB mode does not use an IV, so iv_len should be 0
+    cipher = OpenSSL::Cipher.new 'AES-128-ECB'
+    assert_equal 0, cipher.iv_len
+    cipher = OpenSSL::Cipher.new 'AES-192-ECB'
+    assert_equal 0, cipher.iv_len
+    cipher = OpenSSL::Cipher.new 'AES-256-ECB'
+    assert_equal 0, cipher.iv_len
+  end
+
+
   @@test_encrypt_decrypt_des_variations = nil
 
   def test_encrypt_decrypt_des_variations