Android Open Source - Butler Package Verifier

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License

The source code is released under:

Apache License

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Java Source Code

/**
 * Copyright 2013 Ricky Tobing/*w  ww  .  ja  v  a2  s  .c om*/
 *
 * 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.bingzer.android;

import android.content.Context;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.content.pm.PackageManager.NameNotFoundException;
import android.content.pm.Signature;

import java.security.KeyFactory;
import java.security.PublicKey;
import java.security.spec.X509EncodedKeySpec;

import javax.security.cert.X509Certificate;

/**
 * Used to verify a pacakge name against specified public key
 */
@SuppressWarnings("UnusedDeclaration")
public class PackageVerifier {
  
  private boolean checked = false;
  private boolean verified = false;
  private String packageName;
  private PublicKey publicKey;
  
  public PackageVerifier(String packageName){
    this.packageName = packageName;
  }
  
  public void setPublicKey(int resourceId){
    setPublicKey(Res.readRaw(resourceId));
  }
  
  public void setPublicKey(CharSequence pubKeyBase64){
    try{
      byte[] pubKeyBytes = android.util.Base64.decode(pubKeyBase64.toString(), android.util.Base64.DEFAULT);
      X509EncodedKeySpec keySpec = new X509EncodedKeySpec(pubKeyBytes);
      KeyFactory keyFactory = KeyFactory.getInstance("RSA");
      PublicKey pubKey = keyFactory.generatePublic(keySpec);
      setPublicKey(pubKey);
    }
    catch (Throwable e){
      // ignore
    }
  }
  
  public void setPublicKey(PublicKey pubKey){
    this.publicKey = pubKey;
  }
  
  public boolean isVerified(){
    return verified;
  }
  
  public boolean isChecked(){
    return checked;
  }
  
  public boolean verify(Context context, boolean recheck){
    if(recheck) {
      verified = false;
      checked = false;
    }
    if(!checked){

      try{
        PackageInfo pkgInfo = Res.getPackageInfo(packageName, PackageManager.GET_SIGNATURES);
                assert pkgInfo.signatures != null;
                for (Signature appSignature : pkgInfo.signatures){
          try{
            X509Certificate cert = X509Certificate.getInstance(appSignature.toByteArray());
            cert.verify(publicKey);
            verified = true;
            break;
          }
          catch (Exception e){
            verified = false;
          }
        }// for each signature
      }
      catch (NameNotFoundException nfne){
        verified = false;
      }
      catch (Throwable e){
        verified = false;
        checked = false;
      }
      finally{
        checked = true;
      }
    }
    
    return verified;
  }
}

Java Source Code List