dovecot - Oct 2022 - SNI Config

On 11.10.22 17:46, Paul Kudla (SCOM.CA Internet Services Inc.)
wrote:
> ok according to
> https://www.openssl.org/docs/man1.0.2/man5/x509v3_config.html
> SAN is not a valid option along with CN
... I don't see that being said in the page you refer to?

Anyhow, "stop giving a CN, use SANs instead" is a rather recent 
development coming from the CA/Browser Forum - and IIUC still not a 
*requirement*, not even for web browsers/servers. I would be surprised 
if OpenSSL (already) were trying to enforce that policy.

Hmmm, what's our company's "IMAPS server" throwing at my TB
again ... ?
> $ openssl s_client -connect outlook.office365.com:993 -showcerts | openssl
x509 -noout -text
[...]
>         Subject: C = US, ST = Washington, L = Redmond, O = Microsoft
Corporation, CN = outlook.com
[...]
>             X509v3 Subject Alternative Name: 
>                 DNS:*.clo.footprintdns.com, DNS:*.hotmail.com,
DNS:*.internal.outlook.com, [...]
... yeah, no, nothing that Thunderbird (from 69-ish to 102) should get 
indigestion over.
> Upoin further testing thunderbird seems to be locking onto the primary 
> domain (*.scom.ca) of the server skipp any sni setup ??
You might want to get a network trace of your Thunderbird talking to the 
server to see what cert actually is presented by the server, and 
ideally, what domain is requested by SNI (if at all). That all happens 
before the connection starts to be encrypted, so you should be able to 
read it (say, with Wireshark) without having to crack any crypto ...

Kind regards,
-- 
Jochen Bern
Systemingenieur

Binect GmbH

ok thanks for your input

I finally tracked down the issue

It was how i was loading the certificates in the first place

that being said (and i must have missed this) 2.3.18 seems to allow 
importing a cert from a program

thus sni config

local_name mail.paulkudla.net {
   ssl_key =/programs/common/getssl.cert -k mail.paulkudla.net -q yes
   ssl_cert =/programs/common/getssl.cert -r mail.paulkudla.net -q yes
   ssl_ca =/programs/common/getssl.cert -i mail.paulkudla.net -q yes
}

would work instead of file pipes from individual text files.


#local_name mail.paulkudla.net {
#  ssl_key =</usr/local/etc/dovecot/pk.key
#  ssl_cert =</usr/local/etc/dovecot/pk.crt
#  ssl_ca =</usr/local/etc/dovecot/pk.ca
#}

2.3.19 apparently no longer supports this?

aki is there a way to pipe the cert from a program file (as indicated above)

I am sure you can appreciate generating files for 1000+ ssl certs can 
become a nightmare management wise

either that or a pgsql select ?

I have gone back to text files in the mean time ?



Happy Wednesday !!!
Thanks - paul

Paul Kudla


Scom.ca Internet Services <http://www.scom.ca>
004-1009 Byron Street South
Whitby, Ontario - Canada
L1N 4S3

Toronto 416.642.7266
Main?1.866.411.7266
Fax?1.888.892.7266
Email?paul at scom.ca

On 10/11/2022 12:46 PM, Jochen Bern wrote:
> 
> On 11.10.22 17:46, Paul Kudla (SCOM.CA Internet Services Inc.) wrote:
>> ok according to
>> https://www.openssl.org/docs/man1.0.2/man5/x509v3_config.html
>> SAN is not a valid option along with CN
> 
> ... I don't see that being said in the page you refer to?
> 
> Anyhow, "stop giving a CN, use SANs instead" is a rather recent 
> development coming from the CA/Browser Forum - and IIUC still not a 
> *requirement*, not even for web browsers/servers. I would be surprised 
> if OpenSSL (already) were trying to enforce that policy.
> 
> Hmmm, what's our company's "IMAPS server" throwing at my
TB again ... ?
> 
>> $ openssl s_client -connect outlook.office365.com:993 -showcerts | 
>> openssl x509 -noout -text
> [...]
>> ??????? Subject: C = US, ST = Washington, L = Redmond, O = Microsoft 
>> Corporation, CN = outlook.com
> [...]
>> ??????????? X509v3 Subject Alternative Name:                 
>> DNS:*.clo.footprintdns.com, DNS:*.hotmail.com, 
>> DNS:*.internal.outlook.com, [...]
> 
> ... yeah, no, nothing that Thunderbird (from 69-ish to 102) should get 
> indigestion over.
> 
>> Upoin further testing thunderbird seems to be locking onto the primary 
>> domain (*.scom.ca) of the server skipp any sni setup ??
> 
> You might want to get a network trace of your Thunderbird talking to the 
> server to see what cert actually is presented by the server, and 
> ideally, what domain is requested by SNI (if at all). That all happens 
> before the connection starts to be encrypted, so you should be able to 
> read it (say, with Wireshark) without having to crack any crypto ...
> 
> Kind regards,