GenSecretServlet.java

/*
 * Copyright 2012-2013 Mathias Herberts 
 *
 *    Licensed 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.geoxp.oss.servlet;

import java.io.IOException;
import java.util.Arrays;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.bouncycastle.util.encoders.Base64;
import org.bouncycastle.util.encoders.Hex;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.geoxp.oss.CryptoHelper;
import com.geoxp.oss.OSS;
import com.geoxp.oss.OSS.OSSToken;
import com.geoxp.oss.OSSException;
import com.google.inject.Singleton;

@Singleton
public class GenSecretServlet extends HttpServlet {
  
  private static final Logger LOGGER = LoggerFactory.getLogger(GenSecretServlet.class);
  
  @Override
  protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

    if (!OSS.isInitialized()) {
      resp.sendError(HttpServletResponse.SC_BAD_REQUEST, "Open Secret Server not yet initialized.");
      return;
    }

    //
    // Extract token
    //
    
    String token = req.getParameter("token");
    
    if (null == token) {
      resp.sendError(HttpServletResponse.SC_BAD_REQUEST, "Missing 'token'.");
    }
    
    //
    // Decode token
    //
    
    byte[] tokendata = Base64.decode(token);
    
    //
    // Extract OSS Token
    //
    
    OSSToken osstoken = null;
    
    try {
      osstoken = OSS.checkToken(tokendata);
    } catch (OSSException osse) {
      LOGGER.error("doPost", osse);
      resp.sendError(HttpServletResponse.SC_BAD_REQUEST, osse.getMessage());
      return;
    }
    
    //
    // Check that requesting key can indeed generate secrets
    //
    
    if (!OSS.checkGenSecretSSHKey(osstoken.getKeyblob())) {
      LOGGER.error("[" + new String(Hex.encode(CryptoHelper.sshKeyBlobFingerprint(osstoken.getKeyblob()))) + "] (unauthorized) attempted to generate secret '" + new String(osstoken.getSecret(), "UTF-8") + "'.");
      resp.sendError(HttpServletResponse.SC_FORBIDDEN, "SSH Key cannot generate a new secret.");
      return;
    }
    
    //
    // Generate secret (and nonce)
    //
    
    byte[] secret = new byte[32];
    
    CryptoHelper.getSecureRandom().nextBytes(secret);
    
    //
    // Wrap with master key
    //
    
    byte[] k = OSS.getMasterSecret();
    byte[] wrappedsecret = CryptoHelper.wrapBlob(k, secret);
    Arrays.fill(k, (byte) 0);
    Arrays.fill(secret, (byte) 0);
    
    try {
      OSS.getKeyStore().putSecret(new String(osstoken.getSecret(), "UTF-8"), wrappedsecret);
      LOGGER.info("[" + new String(Hex.encode(CryptoHelper.sshKeyBlobFingerprint(osstoken.getKeyblob()))) + "] generated secret '" + new String(osstoken.getSecret(), "UTF-8") + "'.");
    } catch (OSSException osse) {
      LOGGER.error("doPost", osse);
      resp.sendError(HttpServletResponse.SC_BAD_REQUEST, osse.getMessage());
      return;
    }
    
    resp.setStatus(HttpServletResponse.SC_OK);
  }
}