Could not connect to SMTP host,PKIX path building failed,unable to find valid certification path...

Posted 2022-03-22 GW_Cheng

java发邮件时遇到的问题

公司最近将邮件系统进行了升级，升级之后的邮件必须采用邮件加密传输通道。也就是ssl登录。

之前写的普通登录也将无法使用。今天在修改程序的过程中出现了一些问题，最终都顺利解决了，记录一下。

登录方式

普通登录

    <bean id="mailSender" class="org.springframework.mail.javamail.JavaMailSenderImpl">
        <property name="host" value="$mail.smtp.host" />
        <property name="javaMailProperties">
            <props>
                <prop key="mail.smtp.auth">$mail.smtp.auth</prop>
                <prop key="mail.smtp.timeout">$mail.smtp.timeout</prop>
            </props>
        </property>
        <property name="username" value="$mail.smtp.username" />
        <property name="password" value="$mail.smtp.password" />
    </bean>

ssl登录

<bean id="mailSender" class="org.springframework.mail.javamail.JavaMailSenderImpl">
        <property name="host" value="$mail.smtp.host" />
        <property name="port" value="$mail.smtp.port" />
        <property name="username" value="$mail.smtp.username" />
        <property name="password" value="$mail.smtp.password" />
        <property name="javaMailProperties">
            <props>
                <prop key="mail.smtp.timeout">$mail.smtp.timeout</prop>
                <prop key="mail.smtp.auth">$mail.smtp.auth</prop>
                <prop key="mail.smtp.starttls.enable">$mail.smtp.starttls.enable</prop>
                <prop key="mail.smtp.socketFactory.port">$mail.smtp.port</prop>
                <prop key="mail.smtp.socketFactory.class">javax.net.ssl.SSLSocketFactory</prop>
                <prop key="mail.smtp.socketFactory.fallback">false</prop>
            </props>
        </property>
</bean>

配置文件

#------------------------------------------------------------------------------------
# 邮件服务的配置
#------------------------------------------------------------------------------------
#服务器
mail.smtp.host=smtp.abc.com
#端口号，QQ邮箱需要使用SSL，端口号465或587，其他邮箱默认的端口号：25
mail.smtp.port=465
#STARTTLS是对纯文本通信协议的扩展。它提供一种方式将纯文本连接升级为加密连接（TLS或SSL）
mail.smtp.starttls.enable=true
#是否需要验证密码
mail.smtp.auth=true
#超时时间
mail.smtp.timeout=50000
#------------------------------------------------------------------------------------
# 加解密密钥 不能给出
# 对用户名和密码都进行了加密 加解密工具在DESUtil中
#------------------------------------------------------------------------------------
#登陆用户名 我是随便写的
mail.smtp.username=CBoch2LlydMW2432VYReDe4tjvJRstAmCoE123111
#密码 qq为授权码 111111我是随便写的
mail.smtp.password=avq5JeBiMuNr5F4wclLZZA==

改为ssl后遇到的问题

Mail server connection failed; nested exception is javax.mail.MessagingException: Could not connect to SMTP host: smtp.abc.com, port: 465;

nested exception is:
javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target. Failed messages: javax.mail.MessagingException: Could not connect to SMTP host: smtp.abc.com, port: 465;

nested exception is:
javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

错误为：

1. Could not connect to SMTP host: smtp.abc.com, port: 465
2. PKIX path building failed
3. unable to find valid certification path to requested target

其中1和2是由3引起的

现在问题就是解决

unable to find valid certification path to requested target

网上有两种解决方案

1 安装数字证书
2 生成证书

我把公司的数字证书安装后没有解决问题，采用第二种方法解决

参考文献
http://www.tuicool.com/articles/zUjiIb

其中这篇文章中有一个地方在邮件系统中需要注意
url需要加上端口号

看到如下信息表示成功地生成了证书

将生成的jssecacerts文件拷贝到%JAVA_HONME%\\jre\\lib\\security\\目录下就ok了。

附上InstallCert.java

/*
 * Copyright 2006 Sun Microsystems, Inc.  All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Sun Microsystems nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.security.KeyStore;
import java.security.MessageDigest;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;

import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLException;
import javax.net.ssl.SSLSocket;
import javax.net.ssl.SSLSocketFactory;
import javax.net.ssl.TrustManager;
import javax.net.ssl.TrustManagerFactory;
import javax.net.ssl.X509TrustManager;

public class InstallCert 

    public static void main(String[] args) throws Exception 
        String host;
        int port;
        char[] passphrase;
        if ((args.length == 1) || (args.length == 2)) 
            String[] c = args[0].split(":");
            host = c[0];
            port = (c.length == 1) ? 443 : Integer.parseInt(c[1]);
            String p = (args.length == 1) ? "changeit" : args[1];
            passphrase = p.toCharArray();
         else 
            System.out
                    .println("Usage: java InstallCert <host>[:port] [passphrase]");
            return;
        

        File file = new File("jssecacerts");
        if (file.isFile() == false) 
            char SEP = File.separatorChar;
            File dir = new File(System.getProperty("java.home") + SEP + "lib"
                    + SEP + "security");
            file = new File(dir, "jssecacerts");
            if (file.isFile() == false) 
                file = new File(dir, "cacerts");
            
        
        System.out.println("Loading KeyStore " + file + "...");
        InputStream in = new FileInputStream(file);
        KeyStore ks = KeyStore.getInstance(KeyStore.getDefaultType());
        ks.load(in, passphrase);
        in.close();

        SSLContext context = SSLContext.getInstance("TLS");
        TrustManagerFactory tmf = TrustManagerFactory
                .getInstance(TrustManagerFactory.getDefaultAlgorithm());
        tmf.init(ks);
        X509TrustManager defaultTrustManager = (X509TrustManager) tmf
                .getTrustManagers()[0];
        SavingTrustManager tm = new SavingTrustManager(defaultTrustManager);
        context.init(null, new TrustManager[]  tm , null);
        SSLSocketFactory factory = context.getSocketFactory();

        System.out
                .println("Opening connection to " + host + ":" + port + "...");
        SSLSocket socket = (SSLSocket) factory.createSocket(host, port);
        socket.setSoTimeout(10000);
        try 
            System.out.println("Starting SSL handshake...");
            socket.startHandshake();
            socket.close();
            System.out.println();
            System.out.println("No errors, certificate is already trusted");
         catch (SSLException e) 
            System.out.println();
            e.printStackTrace(System.out);
        

        X509Certificate[] chain = tm.chain;
        if (chain == null) 
            System.out.println("Could not obtain server certificate chain");
            return;
        

        BufferedReader reader = new BufferedReader(new InputStreamReader(
                System.in));

        System.out.println();
        System.out.println("Server sent " + chain.length + " certificate(s):");
        System.out.println();
        MessageDigest sha1 = MessageDigest.getInstance("SHA1");
        MessageDigest md5 = MessageDigest.getInstance("MD5");
        for (int i = 0; i < chain.length; i++) 
            X509Certificate cert = chain[i];
            System.out.println(" " + (i + 1) + " Subject "
                    + cert.getSubjectDN());
            System.out.println("   Issuer  " + cert.getIssuerDN());
            sha1.update(cert.getEncoded());
            System.out.println("   sha1    " + toHexString(sha1.digest()));
            md5.update(cert.getEncoded());
            System.out.println("   md5     " + toHexString(md5.digest()));
            System.out.println();
        

        System.out
                .println("Enter certificate to add to trusted keystore or 'q' to quit: [1]");
        String line = reader.readLine().trim();
        int k;
        try 
            k = (line.length() == 0) ? 0 : Integer.parseInt(line) - 1;
         catch (NumberFormatException e) 
            System.out.println("KeyStore not changed");
            return;
        

        X509Certificate cert = chain[k];
        String alias = host + "-" + (k + 1);
        ks.setCertificateEntry(alias, cert);

        OutputStream out = new FileOutputStream("jssecacerts");
        ks.store(out, passphrase);
        out.close();

        System.out.println();
        System.out.println(cert);
        System.out.println();
        System.out
                .println("Added certificate to keystore 'jssecacerts' using alias '"
                        + alias + "'");
    

    private static final char[] HEXDIGITS = "0123456789abcdef".toCharArray();

    private static String toHexString(byte[] bytes) 
        StringBuilder sb = new StringBuilder(bytes.length * 3);
        for (int b : bytes) 
            b &= 0xff;
            sb.append(HEXDIGITS[b >> 4]);
            sb.append(HEXDIGITS[b & 15]);
            sb.append(' ');
        
        return sb.toString();
    

    private static class SavingTrustManager implements X509TrustManager 

        private final X509TrustManager tm;
        private X509Certificate[] chain;

        SavingTrustManager(X509TrustManager tm) 
            this.tm = tm;
        

        public X509Certificate[] getAcceptedIssuers() 
            throw new UnsupportedOperationException();
        

        public void checkClientTrusted(X509Certificate[] chain, String authType)
                throws CertificateException 
            throw new UnsupportedOperationException();
        

        public void checkServerTrusted(X509Certificate[] chain, String authType)
                throws CertificateException 
            this.chain = chain;
            tm.checkServerTrusted(chain, authType);
        
    

注意

不能将在自己电脑上生成的jssecacerts文件拷贝到服务器上去，如果拷贝上去不会起作用，仍然会报错。
服务器必须编译InstallCert.java，去生成jssecacerts文件。

参考文献

1.解决PKIX问题：unable to find valid certification path to requested target

2.Java发邮件-QQ服务器认证（A secure connection is requiered(such as ssl)）