并发下的Base64解码问题

上一篇文章中介绍的接口加密方案上线至今已有月余，考虑到加密后影响业务的风险以及用户的升级体验，近两个版本采用了明文和密文并存的灰度升级方式，这次发布的版本中决定完全移除明文请求，所以看了一眼近一个月加密逻辑中记录的日志，发现了一些问题。

在日志中存在很多以下报错信息：

错误最终从RSA解密方法中抛出，错误类型有：

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javax.crypto.BadPaddingException: data hash wrong
	at org.bouncycastle.jce.provider.JCERSACipher.engineDoFinal(Unknown Source) ~[bcprov-jdk14-138.jar:1.38.0]
	at javax.crypto.Cipher.doFinal(Cipher.java:2145) ~[na:1.7.0_10]

也有：

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org.bouncycastle.crypto.DataLengthException: input too large for RSA cipher.
	at org.bouncycastle.crypto.engines.RSACoreEngine.convertInput(Unknown Source) ~[bcprov-jdk14-138.jar:1.38.0]
	at org.bouncycastle.crypto.engines.RSAEngine.processBlock(Unknown Source) ~[bcprov-jdk14-138.jar:1.38.0]
	at org.bouncycastle.crypto.encodings.OAEPEncoding.decodeBlock(Unknown Source) ~[bcprov-jdk14-138.jar:1.38.0]
	at org.bouncycastle.crypto.encodings.OAEPEncoding.processBlock(Unknown Source) ~[bcprov-jdk14-138.jar:1.38.0]
	at org.bouncycastle.jce.provider.JCERSACipher.engineDoFinal(Unknown Source) ~[bcprov-jdk14-138.jar:1.38.0]
	at javax.crypto.Cipher.doFinal(Cipher.java:2145) ~[na:1.7.0_10]

处理密文的切面中代码逻辑大致如下：

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logger.info("enToken  : {}", enToken);
logger.info("enParams  : {}", enParams);
String deKey = RSAUtil.decrypt(enToken, RSAUtil.privateKey);

RSAUtil中的RSA解密逻辑为：

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public class RSAUtil {
    private static final BASE64Decoder base64Decoder = new BASE64Decoder();
    
    public static String decrypt(String text, PrivateKey privateKey) {
        try {
            Security.addProvider(new BouncyCastleProvider());
            Cipher cipher = Cipher.getInstance("RSA/NONE/OAEPWithSHA1AndMGF1Padding", "BC");
            cipher.init(Cipher.DECRYPT_MODE, privateKey);
            byte[] encryptedData = base64Decoder.decodeBuffer(text);
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            int offSet = 0;
            int i = 0;
            while (encryptedData.length - offSet > 0) {
                byte[] cache;
                if ((encryptedData.length - offSet) > (KEY_LENGTH / 8)) {
                    cache = cipher.doFinal(encryptedData, offSet, KEY_LENGTH / 8);
                } else {
                    cache = cipher.doFinal(encryptedData, offSet, encryptedData.length - offSet);
                }
                out.write(cache, 0, cache.length);
                i++;
                offSet = i * (KEY_LENGTH / 8);
            }
            return out.toString();
        } catch (Exception e) {
            LOG.error("解密发生异常", e);
            return null;
        }
    }
}

错误抛出的位置都在Cipher.doFinal()方法上。虽然日志中报错解密失败，但是直接拿日志中打印的enParams和enToken又是可以成功解密的，这也是之所以这个报错之前没有引起我重视的原因，本地无法复现。

今天突然想到是不是因为并发的原因导致的本地无法复现，只在线上环境出现，所以写了一小段代码模拟了一下：

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@Test
public void testdecrypt() {
    List<String> enTokenList = new ArrayList<>(100);
    for(int i=0; i<100; i++) {
        String result = RSAUtil.encrypt(String.valueOf(i), RSAUtil.publicKey);
        enTokenList.add(result);
    }
    for(String enToken : enTokenList) {
        ThreadPoolFactory.getThreadPool().execute(new TeEncrypt(enToken));
    }
}

class TeEncrypt implements Runnable{

    private String enToken;

    public TeEncrypt(String enToken) {
        this.enToken = enToken;
    }

    @Override
    public void run() {
        String deco = RSAUtil.decrypt(enToken, RSAUtil.privateKey);
        System.out.println(deco);
    }
}

代码的逻辑比较简单，预先生成了100条密文，然后通过线程池不加任何同步锁来模拟并发的情况，果然复现了线上的报错：

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23:49:24.522 [pool-1-thread-1] ERROR tech.suclogger.common.utils.RSAUtil - 解密发生异常
javax.crypto.BadPaddingException: data hash wrong
	at org.bouncycastle.jce.provider.JCERSACipher.engineDoFinal(Unknown Source) ~[bcprov-jdk14-138.jar:1.38.0]
	at javax.crypto.Cipher.doFinal(Cipher.java:2145) ~[na:1.7.0_71]
	at tech.suclogger.common.utils.RSAUtil.decrypt(RSAUtil.java:195) [classes/:na]
	at tech.suclogger.common.utils.RSAUtil.decrypt(RSAUtil.java:220) [classes/:na]
	at tech.suclogger.web.encrypt.EncryptTest$TeEncrypt.run(EncryptTest.java:39) [test-classes/:na]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [na:1.7.0_75]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [na:1.7.0_75]
	at java.lang.Thread.run(Thread.java:745) [na:1.7.0_75]
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23:49:24.524 [pool-1-thread-43] ERROR tech.suclogger.common.utils.RSAUtil - 解密发生异常
javax.crypto.BadPaddingException: data hash wrong
	at org.bouncycastle.jce.provider.JCERSACipher.engineDoFinal(Unknown Source) ~[bcprov-jdk14-138.jar:1.38.0]
	at javax.crypto.Cipher.doFinal(Cipher.java:2145) ~[na:1.7.0_71]
	at tech.suclogger.common.utils.RSAUtil.decrypt(RSAUtil.java:195) [classes/:na]
	at tech.suclogger.common.utils.RSAUtil.decrypt(RSAUtil.java:220) [classes/:na]
	at tech.suclogger.web.encrypt.EncryptTest$TeEncrypt.run(EncryptTest.java:39) [test-classes/:na]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [na:1.7.0_75]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [na:1.7.0_75]
	at java.lang.Thread.run(Thread.java:745) [na:1.7.0_75]
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23:49:24.523 [pool-1-thread-4] ERROR tech.suclogger.common.utils.RSAUtil - 解密发生异常
javax.crypto.BadPaddingException: data hash wrong
	at org.bouncycastle.jce.provider.JCERSACipher.engineDoFinal(Unknown Source) ~[bcprov-jdk14-138.jar:1.38.0]
	at javax.crypto.Cipher.doFinal(Cipher.java:2145) ~[na:1.7.0_71]
	at tech.suclogger.common.utils.RSAUtil.decrypt(RSAUtil.java:195) [classes/:na]
	at tech.suclogger.common.utils.RSAUtil.decrypt(RSAUtil.java:220) [classes/:na]
	at tech.suclogger.web.encrypt.EncryptTest$TeEncrypt.run(EncryptTest.java:39) [test-classes/:na]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [na:1.7.0_75]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [na:1.7.0_75]
	at java.lang.Thread.run(Thread.java:745) [na:1.7.0_75]
null
23:49:24.523 [pool-1-thread-2] ERROR tech.suclogger.common.utils.RSAUtil - 解密发生异常
javax.crypto.BadPaddingException: data hash wrong
	at org.bouncycastle.jce.provider.JCERSACipher.engineDoFinal(Unknown Source) ~[bcprov-jdk14-138.jar:1.38.0]
	at javax.crypto.Cipher.doFinal(Cipher.java:2145) ~[na:1.7.0_71]
	at tech.suclogger.common.utils.RSAUtil.decrypt(RSAUtil.java:195) [classes/:na]
	at tech.suclogger.common.utils.RSAUtil.decrypt(RSAUtil.java:220) [classes/:na]
	at tech.suclogger.web.encrypt.EncryptTest$TeEncrypt.run(EncryptTest.java:39) [test-classes/:na]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [na:1.7.0_75]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [na:1.7.0_75]
	at java.lang.Thread.run(Thread.java:745) [na:1.7.0_75]
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23:49:24.523 [pool-1-thread-42] ERROR tech.suclogger.common.utils.RSAUtil - 解密发生异常
javax.crypto.BadPaddingException: data hash wrong
	at org.bouncycastle.jce.provider.JCERSACipher.engineDoFinal(Unknown Source) ~[bcprov-jdk14-138.jar:1.38.0]
	at javax.crypto.Cipher.doFinal(Cipher.java:2145) ~[na:1.7.0_71]
	at tech.suclogger.common.utils.RSAUtil.decrypt(RSAUtil.java:195) [classes/:na]
	at tech.suclogger.common.utils.RSAUtil.decrypt(RSAUtil.java:220) [classes/:na]
	at tech.suclogger.web.encrypt.EncryptTest$TeEncrypt.run(EncryptTest.java:39) [test-classes/:na]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [na:1.7.0_75]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [na:1.7.0_75]
	at java.lang.Thread.run(Thread.java:745) [na:1.7.0_75]
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23:49:24.526 [pool-1-thread-48] ERROR tech.suclogger.common.utils.RSAUtil - 解密发生异常
javax.crypto.BadPaddingException: data hash wrong
	at org.bouncycastle.jce.provider.JCERSACipher.engineDoFinal(Unknown Source) ~[bcprov-jdk14-138.jar:1.38.0]
	at javax.crypto.Cipher.doFinal(Cipher.java:2145) ~[na:1.7.0_71]
	at tech.suclogger.common.utils.RSAUtil.decrypt(RSAUtil.java:195) [classes/:na]
	at tech.suclogger.common.utils.RSAUtil.decrypt(RSAUtil.java:220) [classes/:na]
	at tech.suclogger.web.encrypt.EncryptTest$TeEncrypt.run(EncryptTest.java:39) [test-classes/:na]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [na:1.7.0_75]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [na:1.7.0_75]
	at java.lang.Thread.run(Thread.java:745) [na:1.7.0_75]
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给异常添加断点：

原因就在于， sun.misc.BASE64Decoder并不是线程安全的，并发的情况下，可以使用替代方案：

java.util.Base64.Decoder （需要java8）
javax.xml.bind.DatatypeConverter.parseBase64Binary(String lexicalXSDBase64Binary)
org.apache.commons.codec.binary.Base64 …

各个方案的性能比较可以看这篇文章。

修改之后用容量为1000的线程池通过了上面的测试代码：

文章目录