SIS and tracing the origin of an attachment

[doug]

Hi All,

I'm trying to trace an attachment within an SIS subdirectory to the 
email message(s) that link to it. I say messages because I'm also using 
dovecot dedup. My understanding is the linked file name is the hash 
value of the attachments contents concatenated with the GUID of the 
email message. I have had marginal success with a message I created myself.

Example: I generated an email with two attachments. Here are the links 
in my attachment directory.
./26/c5/26c5c540d41779d83d2f5388041d05c67d720d9a-73eca8051acd276272310000f2bc99a3
./65/cd/65cd73112a489ef07f17ed5740aa60358e2dd3fb-74eca8051acd276272310000f2bc99a3

In my sent folder the actual GUID of the message is 
75eca8051acd276272310000f2bc99a3.  So the GUID of the attachment is 
based on the GUID of the message, but not exact. The second hex byte 
seems to be decremented as an offset of the attachment index from the 
GUID of the message. At least in my one example.

# doveadm dump 
/mailstore/doug/mail/mailboxes/Sent/dbox-Mails/dovecot.index | grep guid 
| tail -1
     - guid: 75eca8051acd276272310000f2bc99a3

With that actual GUID I can find the message with a search:
# doveadm search -u doug mailbox Sent guid 75eca8051acd276272310000f2bc99a3
doug e5711f1cf2c9294f71090000059b96e4 53526

Now let's try to track down another email when only the HASH-GUID value 
is known. Here is one randomly picked.

./00/a2/00a2d5de3e41053d59bd10084826bbe094aa1c59-57857b09d1a327627e260000f2bc99a3

# doveadm search -A mailbox '*' guid 57857b09d1a327627e260000f2bc99a3
# doveadm search -A mailbox '*' guid 58857b09d1a327627e260000f2bc99a3
# doveadm search -A mailbox '*' guid 59857b09d1a327627e260000f2bc99a3

I repeated this incrementing and decrementing from 5085... through 
5f85... and never located the message.

This seems like it should be trivial but I've been struggling with it 
for days. The GUID isn't random, there must be a way to track the 
attachment back. What am I missing?

And for those wondering why, our virus scanner flagged a number of 
attachments, some with several links, and I want ask the users to delete 
the offending messages so I can purge them from the server. If I can 
find the emails I can give them the mail folder, date/time, and subject 
of the message.

-- 
Doug