spamd weird socket handling

[Alin Dobre <al...@axigenmail.com>]

  Hi everyone,

[I've sent this message to the DEV list a while ago and got no reply]

I'm using a mail server that integrates with spamassassin, by passing the messages from the queue to the spamd daemon via the inet socket (default 127.0.0.1:783) and takes various actions using spamd's response. Everything worked flawlessly for 99.99% of scanned messages, now some messages cannot be scanned and spamd returns:

Sep 13 11:30:09 k9 spamd[27231]: spamd: timeout: (300 second timeout while trying to CHECK) at /usr/bin/spamd line 2000, <GEN82> line 84.

I'm using spamassassin 3.2.3 (latest version) and the following lines are being sent over socket:

'CHECK SPAMC/1.2\r\nContent-length: %d\r\n\r\n', size and then the raw rfc822 message follows. The content-length size is calculated correctly, so this cannot be the problem, otherwise spamd would have returned an error regarding different content lengths. Shortly, the algorithm is: socket.send socket.recv

After digging a while more deeply, I have found out that the spamc client, after sending the message, shuts down writing on the socket and spamd responds immediately. I did the same and it worked. In this case the algo is: socket.send socket.shutdown(write) socket.recv

My questions are: - Why does it work for 99.99% of messages without having to shutdown writing on socket - Why doesn't it work with that message? - If spamd depends on this shutdown, isn't the Content-length specification redundant?

Here's an email that gets timed out when scanning:

$ ./send_message.py test-notok.eml SPAMD/1.0 79 Timeout: (300 second timeout while trying to CHECK)

I have attached the python script as well as the test-notok.eml message.

Thanks in advance!

Regards, Alin.