dovecot - Jun 2013 - Transparent IMAP proxy

Hi,

I'm considering patching Dovecot to work as a transparent (and virus 
scanning) IMAP proxy.

What is the appropriate feature to extend? (I've considered the 
following: IMAPC and reverse proxying, with IMAPC looking more promising 
since it actually parses IMAP communication).

Can anyone who is familiar with the IMAPC code recommend what are the 
most appropriate locations in the code to make the required changes? 
(I've considered hooking the storage virtual functions and making the 
settings local rather than global - but would appreciate more specific 
ideas).

Thanks.

Am 16.06.2013 15:42, schrieb Yonatan Broza:
> I'm considering patching Dovecot to work as a transparent (and virus
scanning) IMAP proxy
why would someone implement a virus scanner on the IMAP-level?
what happens with POP3?

this has to be done on SMTP level long before the message is stored
and not every time a client is downloading a message

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On 16.6.2013, at 16.42, Yonatan Broza <yonatan at cuppcomputing.com>
wrote:
> I'm considering patching Dovecot to work as a transparent (and virus
scanning) IMAP proxy.
> 
> What is the appropriate feature to extend? (I've considered the
following: IMAPC and reverse proxying, with IMAPC looking more promising since
it actually parses IMAP communication).
> 
> Can anyone who is familiar with the IMAPC code recommend what are the most
appropriate locations in the code to make the required changes? (I've
considered hooking the storage virtual functions and making the settings local
rather than global - but would appreciate more specific ideas).
imapc and http://dovecot.org/patches/2.1/mail-filter.tar.gz can do this. But
note that the MIME structure or the parts' sizes must not change. Basically
you'll have to replace the viruses with empty spaces or something.

imapc isn't very efficient though. It translates all IMAP commands to rather
simple ones. So for example a SEARCH won't be passed through to the backend
server.

On 06/16/2013 03:42 PM, Yonatan Broza wrote:
> I'm considering patching Dovecot to work as a transparent (and virus
> scanning) IMAP proxy.
> [...]
Have you considered non transparent caching proxy?