STARTTLS issue with sieve

[Andreas Oster]

Am 08.07.2017 um 23:10 schrieb Heiko Schlittermann:
> Andreas Oster <aoster at novanetwork.de> (Fr 07 Jul 2017 08:15:05 CEST):
>> Hi all,
>>
>> I am currently struggling with an odd sieve/Pigeonhole issue. Some weeks ago
>> I had to replace our dovecot certificate due to expiration. In the past I
>> did use a self-signed certificate, but because we now have a little openssl
>> based CA I have decided to create signed certificate for imaps. Dovecot is
>> happily accepting the new certificate which has integrated the whole
>> cert-chain. Unfortunately Pigeonhole does not seem to like the certificate:
> 
> As it seem, Pigeonhole sends you the full cert chain:
> 
>> *** Starting TLS handshake
>> - Certificate type: X.509
>> - Got a certificate list of 3 certificates.
>> - Certificate[0] info:
>>   - subject `C=DE,ST=Baden-Wuerttemberg,L=Ettlingen,O=NOVA Elektroanlagen
> …
>> - Certificate[2] info:
>>   - subject `C=DE,ST=Baden-Wuerttemberg,L=Ettlingen,O=NOVA Elektroanlagen
>> GmbH,OU=NOVA Root CA,CN=NOVA Root CA', issuer
> 
> The last one being the CA used.
> 
>> SHA-1 fingerprint `95326e3ff12683cc40a85874d562d0a6f15dcb37'
>> - Status: The certificate is NOT trusted. The certificate issuer is unknown.
>> *** PKI verification of server certificate failed...
>> *** Fatal error: Error in the certificate.
>> *** Handshake has failed
> 
> For me it reads as if your client (gnutls-cli) does not trust
> the chain your server sent. (The server doesn't care about the chain).
> 
>> I have checked the certificate with:
>>
>> openssl verify -verbose -CAfile /etc/ssl/certs/ca-chain.cert.pem
>> /etc/ssl/certs/mail.novanetwork.local.cert.pem
>> /etc/ssl/certs/mail.novanetwork.local.cert.pem: OK
> 
> How do you know that gnutls-cli uses the same CA file? Try passing the
> CA file to gnutls-cli?
> 
> The --x509cafile seems to be hardcoded in /usr/lib/x86_64-linux-gnu/libgnutls.so.30 (Debian9, amd64)
> 
> $ strings /usr/lib/x86_64-linux-gnu/libgnutls.so.30 | grep '/etc/ssl'
> /etc/ssl/certs/ca-certificates.crt
> 
> So, on my system gnutls-cli seems to use the same CA store
> (/etc/ssl/certs) as openssl.
> 
>      Best regards from Dresden/Germany
>      Viele Grüße aus Dresden
>      Heiko Schlittermann
> 
Hi all,

in a posting on  the dovecot user list Stephan Bosch pointed out that 
there is already a fix:

https://github.com/dovecot/pigeonhole/commit 
/c80aa7c25b0b4e61bb8e3a91864a355f7f2fa89f

This small change also resolved my sieve login issue.

best regards
Andreas