From 7763f8d12ddcd440bf84d0e643dc4d9d303c4266 Mon Sep 17 00:00:00 2001
From: Kishor Kharbas <kishor.kharbas@intel.com>
Date: Mon, 28 Dec 2015 22:28:49 -0800
Subject: [PATCH] 8143925: Enhancing CounterMode.crypt() for AES

Add intrinsic for CounterMode.crypt() to leverage the parallel nature of AES in Counter(CTR) Mode.

Reviewed-by: kvn, ascarpino
---
 .../com/sun/crypto/provider/CounterMode.java  | 32 ++++++++++++++++++-
 1 file changed, 31 insertions(+), 1 deletion(-)

diff --git a/jdk/src/java.base/share/classes/com/sun/crypto/provider/CounterMode.java b/jdk/src/java.base/share/classes/com/sun/crypto/provider/CounterMode.java
index af52bd74474..684be4f0d76 100644
--- a/jdk/src/java.base/share/classes/com/sun/crypto/provider/CounterMode.java
+++ b/jdk/src/java.base/share/classes/com/sun/crypto/provider/CounterMode.java
@@ -26,7 +26,9 @@
 package com.sun.crypto.provider;
 
 import java.security.InvalidKeyException;
+import java.util.Objects;
 
+import jdk.internal.HotSpotIntrinsicCandidate;
 
 /**
  * This class represents ciphers in counter (CTR) mode.
@@ -138,7 +140,7 @@ final class CounterMode extends FeedbackCipher {
      * <code>cipherOffset</code>.
      *
      * @param in the buffer with the input data to be encrypted
-     * @param inOffset the offset in <code>plain</code>
+     * @param inOff the offset in <code>plain</code>
      * @param len the length of the input data
      * @param out the buffer for the result
      * @param outOff the offset in <code>cipher</code>
@@ -170,6 +172,15 @@ final class CounterMode extends FeedbackCipher {
      * are encrypted on demand.
      */
     private int crypt(byte[] in, int inOff, int len, byte[] out, int outOff) {
+
+        cryptBlockCheck(in, inOff, len);
+        cryptBlockCheck(out, outOff, len);
+        return implCrypt(in, inOff, len, out, outOff);
+    }
+
+    // Implementation of crpyt() method. Possibly replaced with a compiler intrinsic.
+    @HotSpotIntrinsicCandidate
+    private int implCrypt(byte[] in, int inOff, int len, byte[] out, int outOff) {
         int result = len;
         while (len-- > 0) {
             if (used >= blockSize) {
@@ -181,4 +192,23 @@ final class CounterMode extends FeedbackCipher {
         }
         return result;
     }
+
+    // Used to perform all checks required by the Java semantics
+    // (i.e., null checks and bounds checks) on the input parameters to crypt().
+    // Normally, the Java Runtime performs these checks, however, as crypt() is
+    // possibly replaced with compiler intrinsic, the JDK performs the
+    // required checks instead.
+    // Does not check accesses to class-internal (private) arrays.
+    private static void cryptBlockCheck(byte[] array, int offset, int len) {
+        Objects.requireNonNull(array);
+
+        if (offset < 0 || len < 0 || offset >= array.length) {
+            throw new ArrayIndexOutOfBoundsException(offset);
+        }
+
+        int largestIndex = offset + len - 1;
+        if (largestIndex < 0 || largestIndex >= array.length) {
+            throw new ArrayIndexOutOfBoundsException(largestIndex);
+        }
+    }
 }