为什么SSL握手会给出“无法生成DH密钥对”的异常？ [英] Why does SSL handshake give 'Could not generate DH keypair' exception?
问题描述
当我与某些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，我得到以下异常：
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
演示此问题的服务器示例是aperture.esper.net:6697（这是一个IRC服务器）。没有证明问题的服务器示例是kornbluth.freenode.net:6697。 [毫不奇怪，每个网络上的所有服务器共享相同的行为。]
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（如上所述，连接到某些SSL服务器时有效）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();
这是抛出异常的最后一个startHandshake。是的，'trustAllCerts'还有一些魔力;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.)
显然有一种可能性是esper的服务器配置错误，但是我搜索过并没有找到任何其他人的参考资料esper的SSL端口出现问题，'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时会发生什么：
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)
---
如前所述，它确实成功连接，这比你说的更多Java app。
As noted, after all that, it does connect successfully which is more than you can say for my Java app.
如果相关，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).
我链接的错误报告提到解决方法。希望这应该适合你。
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bug JDK-7044060 并最近修复。
This was reported as bug JDK-7044060 and fixed recently.
但请注意，限制仅提高到2048位。对于大小> 2048位，有 JDK-8072452 - 删除DH键的最大素数;修复似乎是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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