Races in 4.0rc1

Smack Smack Dev
1

Hi

Trying out XMPP for the first time, with 4.0rc1, operating against an ejabberd 2.10 host.

I’ve come up against problems with connecting. Firstly :

XMPPConnection connection = new XMPPTCPConnection(config);

connection.connect();

connection.login(“user”, “password1”);

Was bombing on the connection due to “No non-anonymous SASL connection modes” type error.

This is because the all-important message[1] containing the supported SASL modes has not arrived by the time login() is executed. I can’t tell if that’s because the server is slow, or that the pause is in sending the outbound queued message. Either way, it’s a race condition, and inserting

Thread.sleep(30000);

between connect and login fixes it, ugly though that may be.

Secondly, I seemed to have to disable TLS with

config.setSecurityMode(ConnectionConfiguration.SecurityMode.disabled);

If I don’t, then by the time we get to SASLMechanism:170 “sc.hasInitialResponse()”, the answer is ‘no’, and we end up sending ‘null’ as authenticationText (Which unsurprisingly doesn’t work).

tls start and proceed messages have been exchanged [2], so I don’t know why it’s the case that it’s not happy in that route.

[1]

<?xml version='1.0'?>

stream:featuresSCRAM-SHA-1ANONYMOUSDIGEST-MD5PLAIN</m echanism><register xmlns='http://jabber.org/features/iq-register’/></stream:features>

[2]

2

This is because the all-important message[1] containing the supported SASL modes has not arrived by the time login() is executed.

Thanks fore reporting! SMACK-558

Secondly, I seemed to have to disable TLS with

config.setSecurityMode(ConnectionConfiguration.SecurityMode.disabled);

If I don’t, then by the time we get to SASLMechanism:170 “sc.hasInitialResponse()”, the answer is ‘no’,

Could you elaborate that a bit more? How does an enabled TLS affect the SASL authentication? Or in different words: Why is the answer ‘no’ if you don’t set SecurityMode.disabled?

While SMACK-558 sure is a valid as there is a missing synchronization point in Smack (and I also believe your second report to be valid to, i just need some more info about it, to see the problem) I wonder why you are the first to report those. Are you using a heavy latency connection to your xmpp server? Or some kind of mobile/GSM connection?

3

Ok I found a race in packetReader where wait() would timeout, the connectionId would have been set, but features where possibly not yet parsed. I will commit the patch soon in an extra branch. Are you able to build Smack from sources and test it? That would be great. The code can be found here: https://github.com/Flowdalic/Smack

4

I’ll try building from source.

Re: the TLS - what I see in the debug window is

Send:

<stream:stream to=“192.168.111.28” xmlns=“jabber:client” xmlns:stream=“http://etherx.jabber.org/streams” version=“1.0”>

</stream:stream>

– long pause –

<stream:stream to=“mycompany.com” xmlns=“jabber:client” xmlns:stream=“http://etherx.jabber.org/streams” version=“1.0”>

Recv:

<?xml version='1.0'?>

– long pause –

<?xml version='1.0'?>

stream:featuresSCRAM-SHA-1ANONYMOUSDIGEST-MD5PLAIN</m echanism><register xmlns='http://jabber.org/features/iq-register’/></stream:features>

Then @ SASLMechanism.java:170, sc.hasInitialResponse() == false.

I’ll try the latest repo version. FWIW, server is ejabberd 2.10/ubuntu.

5

It appears that TLS failes. Did you configure Smack with a SSLContext that accepts your servers certificate?

6

No … I’m not sure the TLS part is even a bug, but I was surprised it failed the way that it did.

I tried building from git, but it just bombs out with a load of incomplete javadoc that I don’t care about (not being a gradle user I haven’t got the knowledge to fix that).

7

I tried building from git, but it just bombs out with a load of incomplete javadoc that I don’t care about (not being a gradle user I haven’t got the knowledge to fix that).
If you show us some output from the gradle build, we may be able to help.