Why does SSL handshake give 'Could not generat

Question

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

Final cause:

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

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.]

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();

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.)

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?

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=[e-mail]
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=[e-mail]
verify return:1
---
Certificate chain
 0 s:/C=GB/ST=England/L=London/O=EsperNet/OU=aperture.esper.net/CN=*.esper.net/emailAddress=[e-mail]
   i:/C=GB/ST=England/L=London/O=EsperNet/OU=aperture.esper.net/CN=*.esper.net/emailAddress=[e-mail]
---
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=[e-mail]
issuer=/C=GB/ST=England/L=London/O=EsperNet/OU=aperture.esper.net/CN=*.esper.net/emailAddress=[e-mail]
---
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)
---

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

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

Answer 1

If you are using jdk1.7.0_04, upgrade to jdk1.7.0_21. The problem has been fixed in that update.

Answer 2

I use coldfusion 8 on JDK 1.6.45 and had problems with giving me just red crosses instead of images, and also with cfhttp not able to connect to the local webserver with ssl.

my test script to reproduce with coldfusion 8 was

<CFHTTP URL="https://www.onlineumfragen.com" METHOD="get" ></CFHTTP>
<CFDUMP VAR="#CFHTTP#">

this gave me the quite generic error of " I/O Exception: peer not authenticated." I then tried to add certificates of the server including root and intermediate certificates to the java keystore and also the coldfusion keystore, but nothing helped. then I debugged the problem with

java SSLPoke www.onlineumfragen.com 443

and got

javax.net.ssl.SSLException: java.lang.RuntimeException: Could not generate DH keypair

and

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:107)
    ... 10 more

I then had the idea that the webserver (apache in my case) had very modern ciphers for ssl and is quite restrictive (qualys score a+) and uses strong diffie hellmann keys with more than 1024 bits. obviously, coldfusion and java jdk 1.6.45 can not manage this. Next step in the odysee was to think of installing an alternative security provider for java, and I decided for bouncy castle. see also http://www.itcsolutions.eu/2011/08/22/how-to-use-bouncy-castle-cryptographic-api-in-netbeans-or-eclipse-for-java-jse-projects/

I then downloaded the

bcprov-ext-jdk15on-156.jar

from http://www.bouncycastle.org/latest_releases.html and installed it under C:\jdk6_45\jre\lib\ext or where ever your jdk is, in original install of coldfusion 8 it would be under C:\JRun4\jre\lib\ext but I use a newer jdk (1.6.45) located outside the coldfusion directory. it is very important to put the bcprov-ext-jdk15on-156.jar in the \ext directory (this cost me about two hours and some hair ;-) then I edited the file C:\jdk6_45\jre\lib\security\java.security (with wordpad not with editor.exe!) and put in one line for the new provider. afterwards the list looked like

#
# List of providers and their preference orders (see above):
#
security.provider.1=org.bouncycastle.jce.provider.BouncyCastleProvider
security.provider.2=sun.security.provider.Sun
security.provider.3=sun.security.rsa.SunRsaSign
security.provider.4=com.sun.net.ssl.internal.ssl.Provider
security.provider.5=com.sun.crypto.provider.SunJCE
security.provider.6=sun.security.jgss.SunProvider
security.provider.7=com.sun.security.sasl.Provider
security.provider.8=org.jcp.xml.dsig.internal.dom.XMLDSigRI
security.provider.9=sun.security.smartcardio.SunPCSC
security.provider.10=sun.security.mscapi.SunMSCAPI

(see the new one in position 1)

then restart coldfusion service completely. you can then

java SSLPoke www.onlineumfragen.com 443 (or of course your url!)

and enjoy the feeling... and of course

what a night and what a day. Hopefully this will help (partially or fully) to someone out there. if you have questions, just mail me at info ... (domain above).

Answer 3

Recently I have the same issue and after upgrading jdk version from 1.6.0_45 to jdk1.7.0_191 which resolved the issue.