too much header data - Githubissues

trusteddomainproject / OpenDKIM

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too much header data #143

Open frickl opened 2 years ago

frickl commented 2 years ago

Version opendkim 2.11 libmilter version 1.0.1 Mode "s"

Email with > 3600 Adresses in "From:" and "Cc:" (all the same btw..) leads to a logged opendkim-error "Too much header data". That looks okay..

But postfix reports "Service unavailable", because the milter-response seems broken.

thegushi commented 1 year ago

Could you upload your test message?

andreasschulze commented 4 weeks ago

I've the same message in my logs. Turns out, it happen only for messages sent by MS365 to me. I try to write a patch to

log the MTA's queue_id
log the headers name
log the exact size
set a meaningful response

Currently, the code send a temporary error message to the sending MTA. But this should be a permanent reject reason. Right?

andreasschulze commented 4 weeks ago

Update: "too much header data" refer all headers, not only one line. This changes things. It would be enouth to set "MaximumHeaders" to a higher value. But even in this case it's helpful to know current header size...

andreasschulze commented 4 weeks ago

I prepared an PR: https://github.com/trusteddomainproject/OpenDKIM/compare/develop...andreasschulze:OpenDKIM:issue_143

set a meaningful response, disclosing the local, accaptable maximum headersize
log the MTA's queue_id (if syslog is enabled)
reject such messages (instead deferrring)

comments are welcome