XOAUTH2 submission - "500 5.5.2 Line too long"

[Patrick Nagel]

Hi,

On Tuesday, 8 March 2022 16:12:48 CET Rosario Esposito wrote:
> I setup a dovecot submission server, using xoauth2 authentication.
> My roundcube webmail points to dovecot submission.
> In roundcube smtp logs, I see:
> 
[...]
> [08-Mar-2022 15:47:16 +0100]: <qjonb57c> Send: AUTH XOAUTH2 
> dXNlcj1yZXNwb3NpdAFhdXRoPWJlYXJlci<<<...*very long base64 string*....>>>
> [08-Mar-2022 15:47:16 +0100]: <qjonb57c> Recv: 500 5.5.2 Line too long
> 
> Apparently, the problem came out after upgrading from dovecot 2.3.17 to 
> 2.3.18

Interesting, the changelog (https://github.com/dovecot/core/releases/tag/2.3.18) says:

- submission-login: Authentication does not accept OAUTH2 token (or
  other very long credentials) because it considers the line to be too long.

But sorry, not much else I can contribute, I'm just a random passerby.

Patrick.