[stunnel-users] seg fault stunnel 4-14 on SLES10

Jon Howse jonny at stbrn.ac.uk
Fri Sep 22 10:30:37 CEST 2006

Hi, I am getting a seg fault with stunnel on an installation of SLES10.
This is the first SLES10 server I have set up after having set up many
SLES9 servers (approx twelve) which all communicate through stunnel to a
central syslog server. The version of stunnel we are using on SLES9 is:
stunnel-4.05-20.1. The other machines are a mix of 32bit and 64bit
Xeons. The seg fault seems to happen when syslog starts to talk through

The program is a binary rpm install for 64bit SLES10 and is being run in
standalone mode as a client connecting to a stunnel/syslog server
running SLES9.

SLES10 x86_64

Stunnel 4-14-14.2

uname -a: Linux server #1 SMP Tue Jul 25 15:28:49 UTC
2006 x86_64 x86_64 x86_64 GNU/Linux

libc version: libc.so.6 => /lib64/libc.so.6 (0x00002ae068cf2000)

openssl version: OpenSSL 0.9.8a 11 Oct 2005

# Copyright by Michal Trojnara 2002-2004
# --with changes for SuSE package

# client = yes | no
# client mode (remote service uses SSL)
# default: no (server mode)

client = yes

# chroot + user (comment out to disable)
chroot = /var/lib/stunnel/
setuid = stunnel
setgid = nogroup
# note about the chroot feature and the "exec" keyword to start other
# services...
# while the init script /etc/init.d/stunnel will copy the binaries and
# into the chroot jail, more files might be needed in the jail
(configuration files etc.)

pid = /var/run/stunnel.pid

# debugging

debug = 7
output = /var/log/stunnel.log

# Some performance tunings
# disable Nagle algorithm (a.k.a. tinygram prevention, see man 7 tcp)

socket = l:TCP_NODELAY=1
socket = r:TCP_NODELAY=1
# compression = rle

# Workaround for Eudora bug


# Authentication stuff
# verify = 2
# Don't forget to c_rehash CApath; CApath is located inside chroot jail:
# CApath = /certs
# It's often easier to use CAfile: 
# CAfile = /etc/stunnel/certs.pem
# Don't forget to c_rehash CRLpath; CRLpath is located inside chroot

# CRLpath = /crls
# Alternatively you can use CRLfile:
# CRLfile = /etc/stunnel/crls.pem

CAfile = /etc/openldap/rootcert.pem
cert = /etc/ssl/certs/thorincert.pem
key = /etc/ssl/certs/thorinkey.pem
verify = 2


        accept =
        connect = xxx.xxx.xxx.xxx:5140

kernel: Kernel logging (proc) stopped.
Sep 21 13:51:00 thorin kernel: Kernel log daemon terminating.
Sep 21 13:51:01 thorin syslog-ng[3146]: syslog-ng version 1.6.8 going
Sep 21 13:51:01 thorin syslog-ng[3769]: syslog-ng version 1.6.8 starting
Sep 21 13:51:01 thorin syslog-ng[3769]: Changing permissions on special
file /dev/tty10
Sep 21 13:51:01 thorin syslog-ng[3769]: Connection broken to
AF_INET(, reopening in 60 seconds
Sep 21 13:51:06 thorin kernel: klogd 1.4.1, log source = /proc/kmsg
Sep 21 13:51:06 thorin kernel: stunnel[3739]: segfault at
000000005569a9f0 rip 000055555555b793 rsp 00005555556b2f60 error 4

stunnel 4.14 on x86_64-suse-linux-gnu UCONTEXT+POLL+IPv4+LIBWRAP with
OpenSSL 0.9.8a 11 Oct 2005
2006.09.21 13:48:25 LOG7[3396:1]: RAND_status claims sufficient entropy
for the PRNG
2006.09.21 13:48:25 LOG6[3396:1]: PRNG seeded successfully
2006.09.21 13:48:25 LOG7[3396:1]:
Certificate: /etc/ssl/certs/thorincert.pem
2006.09.21 13:48:25 LOG7[3396:1]: Key file: /etc/ssl/certs/thorinkey.pem
2006.09.21 13:48:25 LOG7[3396:1]: Loaded verify certificates
from /etc/openldap/rootcert.pem
2006.09.21 13:48:25 LOG6[3396:1]: file ulimit = 1024 (can be changed
with 'ulimit -n')
2006.09.21 13:48:25 LOG6[3396:1]: poll() used - no FD_SETSIZE limit for
file descriptors
2006.09.21 13:48:25 LOG5[3396:1]: 500 clients allowed
2006.09.21 13:48:25 LOG7[3396:1]: FD 4 in non-blocking mode
2006.09.21 13:48:25 LOG7[3396:1]: FD 5 in non-blocking mode
2006.09.21 13:48:25 LOG7[3396:1]: FD 6 in non-blocking mode
2006.09.21 13:48:25 LOG7[3396:1]: SO_REUSEADDR option set on accept
2006.09.21 13:48:25 LOG7[3396:1]: 5140 bound to
2006.09.21 13:48:25 LOG7[3397:1]: Created pid file /var/run/stunnel.pid
2006.09.21 13:48:25 LOG7[3397:0]: Waiting -1 second(s) for 2 file
2006.09.21 13:49:20 LOG7[3397:0]: CONTEXT 1, FD=4, (IN)->()
2006.09.21 13:49:20 LOG7[3397:0]: CONTEXT 1, FD=6, (IN)->(IN)
2006.09.21 13:49:20 LOG7[3397:1]: 5140 accepted FD=7 from
2006.09.21 13:49:20 LOG7[3397:1]: Creating a new context
2006.09.21 13:49:20 LOG7[3397:1]: Context 2 created
2006.09.21 13:49:20 LOG7[3397:2]: Context swap: 1 -> 2

It waits at the last entry until syslog tries to connect.
And that's where the useful logging stops, after that it's a seg fault.

Hope you can point me in the right direction...

Jon Howse

St Brendan's Sixth Form College --- STAFF e-mail

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