[pmg-devel] applied: [PATCH pmg-api v2] prefix message-id in attachment-quarantine

[Thomas Lamprecht]

Am 6/17/20 um 5:04 PM schrieb Stoiko Ivanov:
> This patch fixes #2785.
> 
> When using the attachment quarantine - the message is:
> a) stored in the quarantine unaltered
> b) sent on with the attachment removed
> 
> Currently we do not change the message in any other way - in particular
> we do not change the message-id header of any of the 2 mails.
> 
> When a mail is released from the attachment quarantine it is sent by PMG
> with the same message-id as the mail with the attachments removed.
> 
> This is a violation of RFC 5322 (see [0]), and additionally newer versions
> of Exchange do accept 2 mails with the same message-id but silently discard
> the second version, thus making the attachment quarantine unusable for
> Exchange users.
> 
> This patch simply prefixes the message-id with 'pmg-aquar-$$' (where $$ is
> the pid of the pmg-smtp-filter process) for the mail without attachment.
> 
> By keeping the original message-id in the headers tracing the mailflow should
> be facilitated.
> 
> The Message-ID is left intact on the original message in order to keep DKIM
> signatures valid (they are invalidated on the modified mail by the removal
> of the attachment anyways).
> 
> [0] https://tools.ietf.org/html/rfc5322 (section 3.6.4)
> 
> Signed-off-by: Stoiko Ivanov <s.ivanov at proxmox.com>
> ---
> v1 -> v2:
> * changed the patch to prefix the existing message_id instead of simply
>   removing it, based on Thomas' suggestion, that it helps in tracing the
>   mail (Thanks!)
> * tested with message-ids without '<','>' and with a mail without a
>   message-id (`swaks` is quite nice for these edge-cases where postfix inists
>   on following sane SMTP behaviour)
> 
>  src/PMG/RuleDB/Remove.pm | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 

applied, thanks!