On Fri, Jan 5, 2018 at 12:50 AM, Theodore Ts'o <ty...@mit.edu> wrote: > On Thu, Jan 04, 2018 at 12:04:34PM +0100, Dmitry Vyukov wrote: >> >> The problem is that it's not _me_, it's a computer program which uses >> some mail delivery system which I don't have full visibility into. I >> don't know if it even gets bounce emails (as far as I understand it's >> not LKML that generates them, LKML SMTP server just returns some error >> code and then it's a responsibility of somebody else to represent it >> by a reply email). If the only way to probe the behavior is to send >> actual emails to LKML (which have high chances to be actually >> delivered to all subscribers), it makes testing somewhat problematic. > > It looks like you're using the App Engine Mail API. You can configure > it to get bounce e-mails[1]. From what I can tell looking at the mail > headers, the mail gets sent via an intermediate SMTP host, such as > mail-it0-f69.google.com before it is delievered to vger. So if vger's > mailer bounces it via an SMTP error, it would be > mail-it0-f69.google.com's responsibility to generate a bounce message, > which you then should be able to catch. > > [1] https://cloud.google.com/appengine/docs/standard/go/mail/bounce > > You should be able to test this by having your app-engine send a > message to "invalid-addr...@vger.kernel.org". I've verified that this > will cause an immediate SMTP error: > > 554 5.0.0 Hi [74.207.234.97], unresolvable address: > <invalid-addr...@vger.kernel.org>; nosuchuser; invalid-addr...@vger.kernel.org > > If it doesn't, you should file an internal bug report since that's > clearly a bug in the App Engine's mail infrastructure. If you can't > get satisfaction that way, my recommendation would be to set up an > Linode server (you can't use GCE because GCE blocks outgoing SMTP > connections) to be your mail gateway, and send the notifications from > a domain such as syzkaller.org, where you have full control of your > mail infrastructure, and you don't have to deal with nonsense such as > DMARC.
Thanks, Ted! This is helpful. I've added handler for bounce emails: https://github.com/google/syzkaller/commit/19c05fffcb1860b2dcf17989b40ca16ed259fdea And I do see them after sending to invalid-addr...@vger.kernel.org. So now hopefully it will sched some light when we get another bounce.
