[stunnel-users] stunnel crashing on connect

Mon Jul 24 17:15:28 CEST 2006

Hi,

I am attempting to run stunnel on Windows XP Pro but it is crashing as soon
as anything connects to it.  I am using it to create a secure TLS tunnel in
front of an SMTP mail server and from what I read I should be able to do
this and stunnel will handle the STARTLS commands.

I downloaded the following windows binary:
	562589 Mar 11 13:02:35 2006  stunnel-4.15-installer.exe

I made minimal changes to stunnel.conf:
	1) added the line "protocol = smtp"
	2) uncommented the debug lines (still crashes if I leave these lines
alone)

I then start stunnel, either as a service or from cmd line - same thing
happens

>From a command prompt I then "telnet localhost 465" and send "EHLO
mydomain.com hi"
Stunnel responds with "250-EHLO mydomain.com hi Welcome".  I am also running
hMailServer on the same machine listening on port 25.  It looks like stunnel
is forwarded the initial EHLO to hMailServer, then hMailServer responds
correctly and stunnel forwards that response back to me.  Then stunnel
crashes immediatly.

Following is the log:

2006.07.20 10:28:41 LOG7[112:1656]: RAND_status claims sufficient entropy
for the PRNG 2006.07.20 10:28:41 LOG6[112:1656]: PRNG seeded successfully
2006.07.20 10:28:41 LOG7[112:1656]: Certificate: stunnel.pem 2006.07.20
10:28:41 LOG7[112:1656]: Key file: stunnel.pem 2006.07.20 10:28:41
LOG7[112:1656]: SSL context initialized for service pop3s 2006.07.20
10:28:41 LOG7[112:1656]: Certificate: stunnel.pem 2006.07.20 10:28:41
LOG7[112:1656]: Key file: stunnel.pem 2006.07.20 10:28:41 LOG7[112:1656]:
SSL context initialized for service imaps 2006.07.20 10:28:41
LOG7[112:1656]: Certificate: stunnel.pem 2006.07.20 10:28:41 LOG7[112:1656]:
Key file: stunnel.pem 2006.07.20 10:28:41 LOG7[112:1656]: SSL context
initialized for service ssmtp 2006.07.20 10:28:41 LOG5[112:1656]: stunnel
4.15 on x86-pc-mingw32-gnu with OpenSSL 0.9.7i 14 Oct 2005 2006.07.20
10:28:41 LOG5[112:1656]: Threading:WIN32 SSL:ENGINE Sockets:SELECT,IPv6
2006.07.20 10:28:41 LOG5[112:2564]: No limit detected for the number of
clients 2006.07.20 10:28:41 LOG7[112:2564]: FD 1884 in non-blocking mode
2006.07.20 10:28:41 LOG7[112:2564]: SO_REUSEADDR option set on accept socket
2006.07.20 10:28:41 LOG7[112:2564]: pop3s bound to 0.0.0.0:995 2006.07.20
10:28:41 LOG7[112:2564]: FD 1872 in non-blocking mode 2006.07.20 10:28:41
LOG7[112:2564]: SO_REUSEADDR option set on accept socket 2006.07.20 10:28:41
LOG7[112:2564]: imaps bound to 0.0.0.0:993 2006.07.20 10:28:41
LOG7[112:2564]: FD 1864 in non-blocking mode 2006.07.20 10:28:41
LOG7[112:2564]: SO_REUSEADDR option set on accept socket 2006.07.20 10:28:41
LOG7[112:2564]: ssmtp bound to 0.0.0.0:465 2006.07.20 10:28:59
LOG7[112:2564]: ssmtp accepted FD=1840 from 127.0.0.1:1543 2006.07.20
10:28:59 LOG7[112:2564]: Creating a new thread 2006.07.20 10:28:59
LOG7[112:2564]: New thread created 2006.07.20 10:28:59 LOG7[112:2936]: ssmtp
started 2006.07.20 10:28:59 LOG7[112:2936]: FD 1840 in non-blocking mode
2006.07.20 10:28:59 LOG7[112:2936]: TCP_NODELAY option set on local socket
2006.07.20 10:28:59 LOG5[112:2936]: ssmtp connected from 127.0.0.1:1543
2006.07.20 10:28:59 LOG7[112:2936]: FD 1812 in non-blocking mode 2006.07.20
10:28:59 LOG7[112:2936]: ssmtp connecting 127.0.0.1:25 2006.07.20 10:28:59
LOG7[112:2936]: connect_wait: waiting 10 seconds 2006.07.20 10:28:59
LOG7[112:2936]: connect_wait: connected 2006.07.20 10:28:59 LOG7[112:2936]:
Remote FD=1812 initialized 2006.07.20 10:28:59 LOG7[112:2936]: TCP_NODELAY
option set on remote socket 2006.07.20 10:28:59 LOG5[112:2936]: Negotiations
for smtp (server side) started 2006.07.20 10:28:59 LOG7[112:2936]: RFC 2487
detected 2006.07.20 10:28:59 LOG7[112:2936]:  <- 220 hmailserver ESMTP
2006.07.20 10:28:59 LOG7[112:2936]:  -> 220220 hmailserver  ESMTP + stunnel
2006.07.20 10:29:09 LOG7[112:2936]:  <- EHLO mydomain.com hi 2006.07.20
10:29:09 LOG7[112:2936]:  -> 250-EHLO mydomain.com hi Welcome

Here is the output of stunnel -version:

stunnel 4.15 on x86-pc-mingw32-gnu with OpenSSL 0.9.7i 14 Oct 2005
Threading:WIN32 SSL:ENGINE Sockets:SELECT,IPv6

Global options
debug           = 5
RNDbytes        = 64
RNDoverwrite    = yes
service         = stunnel
taskbar         = yes

Service-level options
cert            = stunnel.pem
ciphers         = ALL:!ADH:+RC4:@STRENGTH
key             = stunnel.pem
session         = 300 seconds
TIMEOUTbusy     = 300 seconds
TIMEOUTclose    = 60 seconds
TIMEOUTconnect  = 10 seconds
TIMEOUTidle     = 43200 seconds
verify          = none

2006.07.20 10:25:04 LOG3[3256:3456]: Server is down

I tried building the source and debugging it but I only found some batch
files refering to the MS embedded compiler.  Why would I want to compile
this for an embedded or mobile device?  That is what that compiler is for.
What makefile or compiler should I be using on windows if I wish to build
stunnel on windows?  Which I would rather not have to do, I would like to
just use the binary but it is crashing before I ever get a chance to test
it.

Any help would greatly be appreciated.

thanks,

-Kevin