[strongSwan] Duplicate log entries using default configuration

[James Birkett]

Thanks for this.

I suspect I might have been unclear. The systemd service I'm using is the
one installed by the EPEL package is the traditional charon called using
/usr/libexec/strongswan/starter, not the newer charon-systemd variant.

The service file for this is:

[Unit]
Description=strongSwan IPsec IKEv1/IKEv2 daemon using ipsec.conf
After=syslog.target

[Service]
ExecStart=/usr/sbin/strongswan start --nofork
StandardOutput=syslog

[Install]
WantedBy=multi-user.target

What is the purpose of StandardOutput=syslog in this unit file? This
version of charon does do its own logging to syslog (which is also stored
in the journal when using systemd). But having StandardOutput=syslog in the
unit file is causing the duplicate log entries  (one written directly to
syslog, the other written to stdout and then copied to syslog by systemd).
I think it would be helpful to change this to StandardOutput=null to avoid
these duplicate log entries in the default installed configuration.

Using charon-systemd would be a better long-term solution, I'd just rather
use the EPEL package than build my own package that uses charon-systemd and
keep it up to date with security fixes etc.

Thanks again,

James Birkett

On 13 October 2016 at 00:29, Andreas Steffen <andreas.steffen at strongswan.org
> wrote:

> Hi James,
>
> yes, with systemd and journalctl active you have to remove the
> syslog daemon section from strongswan.conf. If you want to change
> the defaults of the systemd logging you can do this in a charon.journal
> section in strongswan.conf. And I personally prefer an additional
> level 0 output going to auth.log. Here is an example of mine:
>
> charon-systemd {
>   journal {
>     default = 1
>     tnc = 2
>     imv = 2
>     pts = 2
>   }
>   syslog {
>     auth {
>       default = 0
>     }
>   }
> }
>
> Best regards
>
> Andreas
>
>
> On 12.10.2016 08:48, James Birkett wrote:
>
>> Out of the box I seem to get every log message from strongswan
>> duplicated, once logged by "charon", then again by "strongswan" after a
>> delay, e.g.
>>
>> Oct 10 12:26:32 sapphire charon: 05[ENC] generating INFORMATIONAL_V1
>> request 1411728704 [ HASH N(DPD) ]
>>
>> followed later by:
>>
>> Oct 10 12:29:32 sapphire strongswan[19104]: 05[ENC] generating
>> INFORMATIONAL_V1 request 1411728704 [ HASH N(DPD) ]
>>
>> I believe this is because the systemd unit file (strongswan.service) has
>> the line:
>> StandardOutput=syslog, causing systemd to relay everything to syslog,
>> but the default /etc/strongswan/strongswan.d/charon-logging.conf also
>> has a syslog section so charon logs directly to syslog itself as well.
>>
>> I suspect the delay between the two copies of the log entries may be
>> related to buffering on standard out, since the logs from "strongswan"
>> always appear in batches with the same timestamp, but I'm not sure.
>>
>> In my case I'm using strongswan-5.4.0 on Centos 7 from EPEL
>> http://koji.fedoraproject.org/koji/buildinfo?buildID=774748 but I have
>> checked the strongswan 5.5 tarball and it appears the systemd unit file
>> and charon-logging.conf are unchanged.
>>
>> I'm not really sure if this is a bug or something specific to my syslog
>> configuration, but given that charon is logging to syslog itself in the
>> default configuration, would it make more sense to set "StandardOutput =
>> null" from the unit file instead? I have made this change on my own
>> system and it appears to have the desired result.
>>
>> Thanks,
>>
>> James Birkett
>>
>>
>>
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> --
> ======================================================================
> Andreas Steffen                         andreas.steffen at strongswan.org
> strongSwan - the Open Source VPN Solution!          www.strongswan.org
> Institute for Internet Technologies and Applications
> University of Applied Sciences Rapperswil
> CH-8640 Rapperswil (Switzerland)
> ===========================================================[ITA-HSR]==
>
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