[stunnel-users] Stunnel 5.45 and 5.46 crashes upon reconnect HTTPS

Mark Brookes mark at loadbalancer.org
Fri Jun 22 15:55:04 CEST 2018


We have just hit the same problem with 5.45. 5.41 does not appear to
exhibit the same issue.

The problem appears to be linked to the client/session.
Using sni if we hit the url with one client the page loads fine, if we hit
stunnel with a second connection from another client on a different IP
their page reloads fine. But if we reload either of those pages stunnel
segfaults with the following message -

Jun 22 11:42:31 lbmaster kernel: stunnel[6510]: segfault at 178 ip
00007fc64fcb5fe0 sp 00007fc6500f5948 error 4 in
libssl.so.1.0.0[7fc64fc75000+65000]

The above was generated with stunnel 5.45 and openssl 1.0.2j-fips. I also
tested it with stunnel built against 1.1.0h and had the same issue.
Below is the config -
pid = /var/run/stunnel/stunnel.pid
debug = local1.0
socket = a:IP_FREEBIND=yes
fips = no
sslVersion = all

[VIP_Name-1]
        cert = /etc/loadbalancer.org/certs/sslcert1/sslcert1.pem
        ciphers =
ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES128-SHA256:ECDHE-RSA-AES256-SHA:AES128-GCM-SHA256:AES256-SHA256:AES128-SHA256:AES256-SHA:AES128-SHA:DHE-RSA-AES256-SHA256:!RC4:!MD5:!aNULL:!EDH:!3DES
        accept = 192.168.0.112:443
        connect = 192.168.0.112:80
        delay = yes
        options = NO_SSLv3
        options = NO_TLSv1
        options = NO_TLSv1.1
        options = DONT_INSERT_EMPTY_FRAGMENTS
        renegotiation = no
        local = 192.168.0.112
        TIMEOUTclose = 0
        [fizzygood]
                sni = VIP_Name-1:lb1.testdomain.co.uk
                cert = /etc/loadbalancer.org/certs/sslcert1/sslcert1.pem
                ciphers =
ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES128-SHA256:ECDHE-RSA-AES256-SHA:AES128-GCM-SHA256:AES256-SHA256:AES128-SHA256:AES256-SHA:AES128-SHA:DHE-RSA-AES256-SHA256:!RC4:!MD5:!aNULL:!EDH:!3DES
                connect = 192.168.0.112:80
                delay = yes
                options = NO_SSLv3
                options = NO_TLSv1
                options = DONT_INSERT_EMPTY_FRAGMENTS
                renegotiation = no
                local = 192.168.0.112

On Thu, 21 Jun 2018 at 20:08, Per Salmi <per.salmi at gmail.com> wrote:

> I have exactly the same problem with stunnel 5.45 and 5.46 crashing on
> second request!
>
> Running on Windows 10 Pro x64 1803.
>
> I also use https to separate traffic to two different sites on the same
> server as the stunnel service.
>
> /Per
>
> Den tor 21 juni 2018 19:04Javier <jamilist.stn at gmx.es> skrev:
>
>> Hi,
>>
>> isn't annoying when you are using an old version, 5.44, and all goes
>> fine, you notice you are outdated and then comes the problems after
>> update? :-P
>>
>>
>> The thing is that yesterday I needed the HTTPS server so I run
>> Stunnel 5.44 for my non-SSL app and all was fine. I updated to 5.46
>> just because I forgot the last time and didn't even run again because
>> I didn't need it.
>>
>> Today I used it and... I had a crash. I tested 5.45 to trace versions
>> back, and it crashes as well. Back to 5.44 and no crash.
>>
>> The crash happens when there is a reload/reconnect/multiconnect
>> (example, 2 connections html+images) by the browser when connects to
>> an HTTPS server.
>>
>> It only happens when using a SNI service.
>>
>> I've been able to trace back the log on those versions and when fails
>> in 5.45 and 5.46 is at the time when it needs to switch to the SNI
>> service.
>>
>> (log from 5.44)
>> SNI: requested servername: xxx
>> SNI: matched pattern: xxx
>> SNI: switched to service [xxx]  <<<<----- BEFORE SWITCH, IT CRASHES on
>> 5.45 and 5.46
>>
>> Imagine you load https://xxx/.
>>
>> The first time is fine, the second, crashes stunnel. Not happening
>> with 5.44.
>>
>> I haven't seen any change to SNI in manual so... :-?
>>
>> These are the configs for the used virtual servers. Nothing has been
>> changed, anyway:
>>
>>
>> [SSL]
>> client = no
>>
>> accept = y.y.y.1:4747
>> connect = y.y.y.2:443
>>
>> [SSL-xxx-SNI]
>> client = no
>> sni = SSL:xxx
>>
>> connect = y.y.y.2:443
>>
>> cert = pem
>> key = pem
>>
>>
>> Don't mind the port numbers. They aren't in conflict.
>>
>>
>> Running on Windows 2000.
>>
>> Regards.
>> _______________________________________________
>> stunnel-users mailing list
>> stunnel-users at stunnel.org
>> https://www.stunnel.org/cgi-bin/mailman/listinfo/stunnel-users
>>
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-- 

Mark Brookes
Loadbalancer.org Ltd.
www.loadbalancer.org


+44 (0)330 380 1064
mark at loadbalancer.org
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