2.3.11 STARTTLS broken if tls_ca_file is defined

[Wolfgang Breyha]

Hi!

I always had
tls_ca_file: /etc/pki/tls/certs/ca-bundle.crt
defined in my imapd.conf.

Since I updated to 2.3.11 yesterday STARTTLS didn't work anymore because
negotiation failed and timed out. $CLIENT was waiting for more packets from
server AFAIS in a tcpdump, where $CLIENT is Thunderbird, gnutls-cli,
apple-mail.

IMAPS always worked...so I searched for differences in the code and found
the "client cert verfication" code triggered by askcert == 1 in tls.c:738

Removing the tls_ca_file definition helped.

I didn't find the exact cause yet since there are no changes in
tls_init_serverengine() since 2.3.10. One thing I noticed was that it
worked when connecting via the loopback interface. But connecting via
network always failed while negotiating STARTTLS.

Log always showed:
00:00 imap[8508]: accepted connection
  +02 imap[8508]: SSL_accept() incomplete -> wait <- here the client waits
  +23 imap[8508]: EOF in SSL_accept() -> fail     <- here client sent FIN
After the FIN from the client, the server sends lots of stuff on the dead
connection and closes with "NO ssl negotiation failed".

cyrus-imapd-2.3.11 was built from invoca.ch src.rpm on fc5 and rhel5.1.
Both failed.

Regards, Wolfgang Breyha
-- 
Wolfgang Breyha <wbreyha at gmx.net> | http://www.blafasel.at/
Vienna University Computer Center | Austria