为什么 SSL 握手会给出“无法生成 DH 密钥对"异常?

问题描述

当我与一些 IRC 服务器(但不是其他服务器 - 可能是由于服务器的首选加密方法)建立 SSL 连接时，我收到以下异常:

When I make an SSL connection with some IRC servers (but not others - presumably due to the server's preferred encryption method) I get the following exception:

Caused by: java.lang.RuntimeException: Could not generate DH keypair
    at com.sun.net.ssl.internal.ssl.DHCrypt.<init>(DHCrypt.java:106)
    at com.sun.net.ssl.internal.ssl.ClientHandshaker.serverKeyExchange(ClientHandshaker.java:556)
    at com.sun.net.ssl.internal.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:183)
    at com.sun.net.ssl.internal.ssl.Handshaker.processLoop(Handshaker.java:593)
    at com.sun.net.ssl.internal.ssl.Handshaker.process_record(Handshaker.java:529)
    at com.sun.net.ssl.internal.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:893)
    at com.sun.net.ssl.internal.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1138)
    at com.sun.net.ssl.internal.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1165)
    ... 3 more

最终原因:

Caused by: java.security.InvalidAlgorithmParameterException: Prime size must be multiple of 64, and can only range from 512 to 1024 (inclusive)
    at com.sun.crypto.provider.DHKeyPairGenerator.initialize(DashoA13*..)
    at java.security.KeyPairGenerator$Delegate.initialize(KeyPairGenerator.java:627)
    at com.sun.net.ssl.internal.ssl.DHCrypt.<init>(DHCrypt.java:100)
    ... 10 more

aperture.esper.net:6697(这是一个 IRC 服务器)是演示此问题的服务器示例.kornbluth.freenode.net:6697 是未证明该问题的服务器示例.[毫不奇怪，每个网络上的所有服务器都共享相同的各自行为.]

An example of a server that demonstrates this problem is aperture.esper.net:6697 (this is an IRC server). An example of a server that does not demonstrate the problem is kornbluth.freenode.net:6697. [Not surprisingly, all servers on each network share the same respective behaviour.]

我的代码(如前所述，在连接到某些 SSL 服务器时确实有效)是:

My code (which as noted does work when connecting to some SSL servers) is:

    SSLContext sslContext = SSLContext.getInstance("SSL");
    sslContext.init(null, trustAllCerts, new SecureRandom());
    s = (SSLSocket)sslContext.getSocketFactory().createSocket();
    s.connect(new InetSocketAddress(host, port), timeout);
    s.setSoTimeout(0);
    ((SSLSocket)s).startHandshake();

最后一次 startHandshake 引发了异常.是的，trustAllCerts"有一些魔力；该代码强制 SSL 系统不验证证书.(所以...不是证书问题.)

It's that last startHandshake that throws the exception. And yes there is some magic going on with the 'trustAllCerts'; that code forces the SSL system not to validate certs. (So... not a cert problem.)

显然，一种可能性是 esper 的服务器配置错误，但我搜索并没有找到任何其他关于 esper 的 SSL 端口有问题的人的引用，并且openssl"连接到它(见下文).所以我想知道这是否是 Java 默认 SSL 支持的限制，或者其他什么.有什么建议吗?

Obviously one possibility is that esper's server is misconfigured, but I searched and didn't find any other references to people having problems with esper's SSL ports, and 'openssl' connects to it (see below). So I'm wondering if this is a limitation of Java default SSL support, or something. Any suggestions?

当我从命令行使用openssl"连接到 Aperture.esper.net 6697 时会发生以下情况:

Here's what happens when I connect to aperture.esper.net 6697 using 'openssl' from commandline:

~ $ openssl s_client -connect aperture.esper.net:6697
CONNECTED(00000003)
depth=0 /C=GB/ST=England/L=London/O=EsperNet/OU=aperture.esper.net/CN=*.esper.net/emailAddress=support@esper.net
verify error:num=18:self signed certificate
verify return:1
depth=0 /C=GB/ST=England/L=London/O=EsperNet/OU=aperture.esper.net/CN=*.esper.net/emailAddress=support@esper.net
verify return:1
---
Certificate chain
 0 s:/C=GB/ST=England/L=London/O=EsperNet/OU=aperture.esper.net/CN=*.esper.net/emailAddress=support@esper.net
   i:/C=GB/ST=England/L=London/O=EsperNet/OU=aperture.esper.net/CN=*.esper.net/emailAddress=support@esper.net
---
Server certificate
-----BEGIN CERTIFICATE-----
[There was a certificate here, but I deleted it to save space]
-----END CERTIFICATE-----
subject=/C=GB/ST=England/L=London/O=EsperNet/OU=aperture.esper.net/CN=*.esper.net/emailAddress=support@esper.net
issuer=/C=GB/ST=England/L=London/O=EsperNet/OU=aperture.esper.net/CN=*.esper.net/emailAddress=support@esper.net
---
No client certificate CA names sent
---
SSL handshake has read 2178 bytes and written 468 bytes
---
New, TLSv1/SSLv3, Cipher is DHE-RSA-AES256-SHA
Server public key is 2048 bit
Secure Renegotiation IS supported
Compression: NONE
Expansion: NONE
SSL-Session:
    Protocol  : TLSv1
    Cipher    : DHE-RSA-AES256-SHA
    Session-ID: 51F1D40A1B044700365D3BD1C61ABC745FB0C347A334E1410946DCB5EFE37AFD
    Session-ID-ctx: 
    Master-Key: DF8194F6A60B073E049C87284856B5561476315145B55E35811028C4D97F77696F676DB019BB6E271E9965F289A99083
    Key-Arg   : None
    Start Time: 1311801833
    Timeout   : 300 (sec)
    Verify return code: 18 (self signed certificate)
---

如上所述，毕竟它确实连接成功，这比我的 Java 应用程序所能说的要多.

As noted, after all that, it does connect successfully which is more than you can say for my Java app.

如果相关的话，我使用的是 OS X 10.6.8，Java 版本 1.6.0_26.

Should it be relevant, I'm using OS X 10.6.8, Java version 1.6.0_26.

推荐答案

问题是素数大小.Java 接受的最大可接受大小是 1024 位.这是一个已知问题(请参阅 JDK-6521495).

The problem is the prime size. The maximum-acceptable size that Java accepts is 1024 bits. This is a known issue (see JDK-6521495).

我链接到的错误报告提到了 解决方法 使用 BouncyCastle 的 JCE 实现.希望这对你有用.

The bug report that I linked to mentions a workaround using BouncyCastle's JCE implementation. Hopefully that should work for you.

更新

这被报告为错误 JDK-7044060 并在最近修复.

This was reported as bug JDK-7044060 and fixed recently.

但请注意，该限制仅提高到 2048 位.对于大小 > 2048 位，有 JDK-8072452 - 删除 DH 密钥的最大素数;修复似乎适用于 9.

Note, however, that the limit was only raised to 2048 bit. For sizes > 2048 bit, there is JDK-8072452 - Remove the maximum prime size of DH Keys; the fix appears to be for 9.

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