Bug#322406: exim4: Excessive use of /dev/random

[John Goerzen]

Package: exim4
Version: 4.52-1
Severity: normal

I had some messages sitting in my queue that just weren't getting
delivered, even though a delivery process had existed for them for over
30 minutes.  They were just sending to a smarthost on the LAN.

It looked like it was hanging after STARTTLS.  (TLS is used to send mail
to the LAN smarthost)

After awhile, I ran with debugging and discovered it was hanging after
this:

10.200.0.2 in hosts_avoid_tls? no (option unset)
  SMTP>> STARTTLS
waiting for data on socket
read response data: size=18
  SMTP<< 220 TLS go ahead
initializing GnuTLS as a client
parameter cache file /var/spool/exim4/gnutls-params does not exist
generating 512 bit RSA key...

Poking around with strace revealed that it was trying to pull from
/dev/random, which was apparently depleted.  (The system was mostly idle
at that time.)

Perhaps exim4 should revert to /dev/urandom if it can't get enough
randomness from /dev/random in a reasonable amount of time.

OTOH, I don't understand why it has to generate a key anyway.

-- Package-specific info:
Exim version 4.52 #1 built 02-Jul-2005 06:12:03
Copyright (c) University of Cambridge 2005
Berkeley DB: Sleepycat Software: Berkeley DB 4.2.52: (December  3, 2003)
Support for: iconv() IPv6 GnuTLS
Lookups: lsearch wildlsearch nwildlsearch iplsearch cdb dbm dbmnz dsearch nis nis0 passwd
Authenticators: cram_md5 plaintext
Routers: accept dnslookup ipliteral manualroute queryprogram redirect
Transports: appendfile/maildir/mailstore autoreply lmtp pipe smtp
Fixed never_users: 0
Configuration file is /var/lib/exim4/config.autogenerated

-- System Information:
Debian Release: testing/unstable
  APT prefers unstable
  APT policy: (500, 'unstable'), (1, 'experimental')
Architecture: i386 (i686)
Shell:  /bin/sh linked to /bin/bash
Kernel: Linux 2.6.13-rc3-mm1
Locale: LANG=C, LC_CTYPE=en_US (charmap=ISO-8859-1)

Versions of packages exim4 depends on:
ii  exim4-base                    4.52-1     support files for all exim MTA (v4
ii  exim4-daemon-light            4.52-1     lightweight exim MTA (v4) daemon

exim4 recommends no packages.

-- no debconf information