Bug#551106: exim4-daemon-heavy: exim segfaults with dovecot auth

[Fabio Muzzi]

Package: exim4-daemon-heavy
Version: 4.69-9
Severity: important


I have just set up exim4 to authenticate using Dovecot on two servers. Both are 64 bit, both use the same version of Exim4 and Dovecot (the latest up to date in Debian) and the configuration is the same for both Dovecot and Exim.

While one works, the other segfaults sistematically when I try to use the dovecot authentication for SMTP sessions. If I use another auth method, it works.

This is an example SMTP session as seen from the client:

========================
kurgan at vongola:~$ telnet hosting1.soultech.it 25
Trying 79.98.45.34...
Connected to hosting1.soultech.it.
Escape character is '^]'.
220 hosting1.soultech.it ESMTP Exim 4.69 Thu, 15 Oct 2009 19:40:35 +0200
ehlo a
250-hosting1.soultech.it Hello a [78.4.122.170]
250-SIZE 104857600
250-PIPELINING
250-AUTH PLAIN LOGIN CRAM-MD5
250-STARTTLS
250 HELP
auth cram-md5
Connection closed by foreign host.
========================

As you can see, as soon as I enter the "auth" request, the connection drops.

On the server, I get this error in the syslog:

Oct 15 19:20:17 hosting1 kernel: [6678213.835528] exim4[19769]: segfault at 6c6ff8 ip 7f804d7f97cc sp 7fff583b0558 error 4 in libc-2.7.so[7f804d77c000+14a000]

If I shut down Dovecot, so that the auth socket is not available, then Exim answers with a "435 Unable to authenticate at present" at the "auth cram-md5" command, and does not crash.

So, as far as I can tell, Exim crashes after connecting to Dovecot and before asking me for a username. I have tried also other auth methods (plain, login) and all of them crash the same way, when I use the dovecot driver.


This is the relevant Exim4.conf part:

==================================================
dovecot_cram:
       driver = dovecot
       public_name = CRAM-MD5
       server_socket = /var/run/dovecot/auth-client
       server_set_id = $auth1
==================================================


I'm baffled. I'll try to run the dovecot authenticator on more servers (all of them are configured the same way, but with different hardware) later and report back.




-- Package-specific info:
Exim version 4.69 #1 built 30-Sep-2008 18:55:37
Copyright (c) University of Cambridge 2006
Berkeley DB: Berkeley DB 4.6.21: (September 27, 2007)
Support for: crypteq iconv() IPv6 PAM Perl Expand_dlfunc GnuTLS move_frozen_messages Content_Scanning Old_Demime
Lookups: lsearch wildlsearch nwildlsearch iplsearch cdb dbm dbmnz dnsdb dsearch ldap ldapdn ldapm mysql nis nis0 passwd pgsql sqlite
Authenticators: cram_md5 cyrus_sasl dovecot plaintext spa
Routers: accept dnslookup ipliteral iplookup manualroute queryprogram redirect
Transports: appendfile/maildir/mailstore/mbx autoreply lmtp pipe smtp
Fixed never_users: 0
Size of off_t: 8
Configuration file is /etc/exim4/exim4.conf
mailname:hosting1.soultech.it

-- System Information:
Debian Release: 5.0.3
  APT prefers stable
  APT policy: (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.26-2-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages exim4-daemon-heavy depends on:
ii  debconf [debconf- 1.5.24                 Debian configuration management sy
ii  exim4-base        4.69-9                 support files for all Exim MTA (v4
ii  libc6             2.7-18                 GNU C Library: Shared libraries
ii  libdb4.6          4.6.21-11              Berkeley v4.6 Database Libraries [
ii  libgnutls26       2.4.2-6+lenny1         the GNU TLS library - runtime libr
ii  libldap-2.4-2     2.4.11-1               OpenLDAP libraries
ii  libmysqlclient15o 5.0.51a-24+lenny2      MySQL database client library
ii  libpam0g          1.0.1-5+lenny1         Pluggable Authentication Modules l
ii  libpcre3          7.6-2.1                Perl 5 Compatible Regular Expressi
ii  libperl5.10       5.10.0-19lenny2        Shared Perl library
ii  libpq5            8.3.8-0lenny1          PostgreSQL C client library
ii  libsasl2-2        2.1.22.dfsg1-23+lenny1 Cyrus SASL - authentication abstra
ii  libsqlite3-0      3.5.9-6                SQLite 3 shared library

exim4-daemon-heavy recommends no packages.

exim4-daemon-heavy suggests no packages.

-- debconf information:
  exim4-daemon-heavy/drec: