Merge remote-tracking branch 'exoscale/feature/constant-time'

This closes #65

Signed-off-by: Rohit Yadav <rohit.yadav@shapeblue.com>

server/src/com/cloud/api/ApiServer.java

@@ -40,6 +40,7 @@ import com.cloud.user.DomainManager;
 import com.cloud.user.User;
 import com.cloud.user.UserAccount;
 import com.cloud.user.UserVO;
+import com.cloud.utils.ConstantTimeComparator;
 import com.cloud.utils.HttpUtils;
 import com.cloud.utils.NumbersUtil;
 import com.cloud.utils.Pair;
@@ -910,9 +911,11 @@ public class ApiServer extends ManagerBase implements HttpRequestHandler, ApiSer
             final SecretKeySpec keySpec = new SecretKeySpec(secretKey.getBytes(), "HmacSHA1");
             mac.init(keySpec);
             mac.update(unsignedRequest.getBytes());
+
             final byte[] encryptedBytes = mac.doFinal();
             final String computedSignature = Base64.encodeBase64String(encryptedBytes);
-            final boolean equalSig = signature.equals(computedSignature);
+            final boolean equalSig = ConstantTimeComparator.compareStrings(signature, computedSignature);
+
             if (!equalSig) {
                 s_logger.info("User signature: " + signature + " is not equaled to computed signature: " + computedSignature);
             } else {

server/src/com/cloud/servlet/ConsoleProxyServlet.java

@@ -54,6 +54,7 @@ import com.cloud.user.Account;
 import com.cloud.user.AccountManager;
 import com.cloud.user.User;
 import com.cloud.uservm.UserVm;
+import com.cloud.utils.ConstantTimeComparator;
 import com.cloud.utils.Pair;
 import com.cloud.utils.Ternary;
 import com.cloud.utils.db.EntityManager;
@@ -659,7 +660,7 @@ public class ConsoleProxyServlet extends HttpServlet {
             mac.update(unsignedRequest.getBytes());
             byte[] encryptedBytes = mac.doFinal();
             String computedSignature = Base64.encodeBase64String(encryptedBytes);
-            boolean equalSig = signature.equals(computedSignature);
+            boolean equalSig = ConstantTimeComparator.compareStrings(signature, computedSignature);
             if (!equalSig) {
                 s_logger.debug("User signature: " + signature + " is not equaled to computed signature: " + computedSignature);
             }

server/src/com/cloud/user/AccountManagerImpl.java

@@ -135,6 +135,7 @@ import com.cloud.user.Account.State;
 import com.cloud.user.dao.AccountDao;
 import com.cloud.user.dao.UserAccountDao;
 import com.cloud.user.dao.UserDao;
+import com.cloud.utils.ConstantTimeComparator;
 import com.cloud.utils.NumbersUtil;
 import com.cloud.utils.Pair;
 import com.cloud.utils.Ternary;
@@ -488,6 +489,7 @@ public class AccountManagerImpl extends ManagerBase implements AccountManager, M
 
     @Override
     public void checkAccess(Account caller, AccessType accessType, boolean sameOwner, String apiName, ControlledEntity... entities) {
+
         //check for the same owner
         Long ownerId = null;
         ControlledEntity prevEntity = null;
@@ -2061,7 +2063,7 @@ public class AccountManagerImpl extends ManagerBase implements AccountManager, M
                 mac.update(unsignedRequest.getBytes());
                 byte[] encryptedBytes = mac.doFinal();
                 String computedSignature = new String(Base64.encodeBase64(encryptedBytes));
-                boolean equalSig = signature.equals(computedSignature);
+                boolean equalSig = ConstantTimeComparator.compareStrings(signature, computedSignature);
                 if (!equalSig) {
                     s_logger.info("User signature: " + signature + " is not equaled to computed signature: " + computedSignature);
                 } else {

utils/src/com/cloud/utils/ConstantTimeComparator.java

@@ -0,0 +1,39 @@
+//
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+//
+
+package com.cloud.utils;
+
+public class ConstantTimeComparator {
+
+    public static boolean compareBytes(byte[] b1, byte[] b2) {
+        if (b1.length != b2.length) {
+            return false;
+        }
+
+        int result = 0;
+        for (int i = 0; i < b1.length; i++) {
+            result |= b1[i] ^ b2[i];
+        }
+        return result == 0;
+    }
+
+    public static boolean compareStrings(String s1, String s2) {
+        return compareBytes(s1.getBytes(), s2.getBytes());
+    }
+}