在Java中针对CA验证X.509证书

Question

可以说我有这样的东西(客户端代码):

TrustManager[] trustAllCerts = new TrustManager[]{
    new X509TrustManager() {

        @Override
        public java.security.cert.X509Certificate[] getAcceptedIssuers() {
            return null;
        }

        @Override
        public void checkClientTrusted(
                java.security.cert.X509Certificate[] certs, String authType) {
        }

        @Override
        public void checkServerTrusted(
                java.security.cert.X509Certificate[] certs, String authType) {
        }
    }
};

SSLContext sslc = SSLContext.getInstance("TLS");
sslc.init(null, trustAllCerts, null);

SocketFactory sf = sslc.getSocketFactory();
SSLSocket s = (SSLSocket) sf.createSocket("127.0.0.1", 9124);

这段代码功能齐全,但我真的无法弄清楚,如何根据我在pem文件中提供的一个具体CA证书来验证服务器的证书.

所有证书都由我的自签名CA签名,它是我需要验证的CA(仅针对此证书).

每个答案都表示赞赏.

编辑:

回应jglouie(非常感谢你这样做 - 不能投票给你答案).

我创立了解决方案:

new X509TrustManager() {

        @Override
        public java.security.cert.X509Certificate[] getAcceptedIssuers() {
            return null;
        }

        @Override
        public void checkClientTrusted(
                java.security.cert.X509Certificate[] certs, String authType) {
        }

        @Override
        public void checkServerTrusted(
                java.security.cert.X509Certificate[] certs, String authType)
                throws CertificateException {
            InputStream inStream = null;
            try {
                // Loading the CA cert
                URL u = getClass().getResource("tcp/cacert.pem");
                inStream = new FileInputStream(u.getFile());
                CertificateFactory cf = CertificateFactory.getInstance("X.509");
                X509Certificate ca = (X509Certificate) cf.generateCertificate(inStream);
                inStream.close();

                for (X509Certificate cert : certs) {
                    // Verifing by public key
                    cert.verify(ca.getPublicKey());
                }
            } catch (Exception ex) {
                Logger.getLogger(Client.class.getName()).log(Level.SEVERE, null, ex);
            } finally {
                try {
                    inStream.close();
                } catch (IOException ex) {
                    Logger.getLogger(Client.class.getName()).log(Level.SEVERE, null, ex);
                }
            }

        }
    }
};

Answer 1

我假设您的CA的自签名证书已经加载如下:

CertificateFactory cf = CertificateFactory.getInstance("X.509");   
FileInputStream finStream = new FileInputStream("CACertificate.pem"); 
X509Certificate caCertificate = (X509Certificate)cf.generateCertificate(finStream);  

然后在检查证书的方法中:

@Override        
 public void checkServerTrusted(java.security.cert.X509Certificate[] certs, String authType)  throws CertificateException {

 if (certs == null || certs.length == 0) {  
      throw new IllegalArgumentException("null or zero-length certificate chain");  
 }  

 if (authType == null || authType.length() == 0) {  
            throw new IllegalArgumentException("null or zero-length authentication type");  
  }  

   //Check if certificate send is your CA's
    if(!certs[0].equals(caCertificate)){
         try
         {   //Not your CA's. Check if it has been signed by your CA
             certs[0].verify(caCertificate.getPublicKey())
         }
         catch(Exception e){   
              throw new CertificateException("Certificate not trusted",e);
         }
    }
    //If we end here certificate is trusted. Check if it has expired.  
     try{
          certs[0].checkValidity();
      }
      catch(Exception e){
            throw new CertificateException("Certificate not trusted. It has expired",e);
      }  
}

免责声明:甚至没有尝试编译代码

Answer 2

接受的答案是非常不正确的。它不会以加密方式验证服务器证书和受信任的证书颁发机构之间的任何连接。一般来说，您几乎不需要实现自己的 TrustManager，这样做是非常危险的。

正如 EJP 所说，不需要实现自己的 TrustManager，您可以使用默认的，并确保受信任的 CA 证书已添加到您的默认 TrustStore。有关更多信息，请参阅此问题。

查看来自 JDK的CertPathValidator类，它验证从服务器自己的证书到受信任的 CA 的连续信任链。有关证书链验证的介绍，请参阅Oracle 的文档。