/**
* Find Security Bugs
* Copyright (c) Philippe Arteau, All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 3.0 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library.
*/
package com.h3xstream.findsecbugs.crypto;
import com.h3xstream.findsecbugs.common.StackUtils;
import edu.umd.cs.findbugs.BugInstance;
import edu.umd.cs.findbugs.BugReporter;
import edu.umd.cs.findbugs.OpcodeStack;
import edu.umd.cs.findbugs.Priorities;
import edu.umd.cs.findbugs.bcel.OpcodeStackDetector;
import java.util.regex.Pattern;
import org.apache.bcel.Constants;
/**
* This detector mark cipher usage that doesn't provide integrity.
* <p>
* The identification will be made base on the mode use.
* </p>
*
* Bad modes:
* <ul>
* <li>ECB</li>
* <li>CBC</li>
* <li>OFB</li>
* <li>...</li>
* </ul>
*
* Safe modes:
* <ul>
* <li>CCM</li>
* <li>CWC</li>
* <li>OCB</li>
* <li>EAX</li>
* <li>GCM</li>
* </ul>
*
* <p>
* Ref: <a href="http://en.wikipedia.org/wiki/Authenticated_encryption">Wikipedia: Authenticated encryption</a>
* Ref for the list of potential ciphers:
* http://docs.oracle.com/javase/7/docs/technotes/guides/security/StandardNames.html#impl
* Note: Not all ECB mode are vulnerable. see RSA/ECB/*
* </p>
*/
public class CipherWithNoIntegrityDetector extends OpcodeStackDetector {
private static final String ECB_MODE_TYPE = "ECB_MODE";
private static final String PADDING_ORACLE_TYPE = "PADDING_ORACLE";
private static final String CIPHER_INTEGRITY_TYPE = "CIPHER_INTEGRITY";
private static final Pattern AUTHENTICATED_CIPHER_MODES = Pattern.compile(".*/(CCM|CWC|OCB|EAX|GCM)/.*");
private static final Pattern INSECURE_ECB_MODES = Pattern.compile("(AES|DES(ede)?)(/ECB/.*)?");
private final BugReporter bugReporter;
public CipherWithNoIntegrityDetector(BugReporter bugReporter) {
this.bugReporter = bugReporter;
}
@Override
public void sawOpcode(int seen) {
if ((seen != Constants.INVOKESTATIC
|| !getClassConstantOperand().equals("javax/crypto/Cipher"))
|| !getNameConstantOperand().equals("getInstance")) {
return;
}
OpcodeStack.Item item = stack.getStackItem(getSigConstantOperand().contains(";L") ? 1 : 0);
String cipherValue;
if (StackUtils.isConstantString(item)) {
cipherValue = (String) item.getConstant();
} else {
return;
}
if (INSECURE_ECB_MODES.matcher(cipherValue).matches()) {
reportBug(ECB_MODE_TYPE);
}
if (cipherValue.contains("/CBC/PKCS5Padding")) {
reportBug(PADDING_ORACLE_TYPE);
}
//Some cipher will not have mode specified (ie: "RSA" .. issue GitHub #24)
if (!AUTHENTICATED_CIPHER_MODES.matcher(cipherValue).matches()
&& !cipherValue.startsWith("RSA")) {
reportBug(CIPHER_INTEGRITY_TYPE);
}
}
private void reportBug(String type) {
bugReporter.reportBug(new BugInstance(this, type, Priorities.HIGH_PRIORITY)
.addClass(this).addMethod(this).addSourceLine(this));
}
}