Re: [Exim] Viral hooks

Top Page
Delete this message
Reply to this message
Author: Jason
Date:  
To: exim-users
Subject: Re: [Exim] Viral hooks
Why not move filtering and delivery out to a seperate process hence the
message is then piped into the new process, therefore no message body
limit?

On 14 Jun 2000, at 17:58, Nigel Metheringham wrote:

> I've been giving a little thought to ways of adding hooks for
> operations such as virus scanning with the following contraints:-
> - not intending to change mail (ie edit headers/bodies)
> - reasonably general
> - reasonably easy to implement
> - understandable :-)
>
>
> I've been wondering about having a filter operation *similar* to piping
> but subtly different, used something like this:-
>
>    cmdprocess /path/to/cmd [args...]

>
> This runs /path/to/cmd at the time that the filter processing is done
> (unlike filter pipes which setup piped deliveries for later), with the
> message on stdin (I would like an option for not having the msg on
> stdin because in some cases it will unproductive) and a standard set of
> environment variables *including* the spool file names (or probably the
> spool file name without -H or -D) for programs that play fast and
> loose. [The files would be locked whilst this is running so thats OK]
>
> The return status is put into a numeric variable (could use an
> existing, in which case add the variable name prior to the cmd path -
> I've assumed a fixed $cmdret), and any generated text appears in
> another variable - say $cmdtext.
>
> I could use this something like:-
>
>     if first_delivery then
>  cmdprocess /usr/sbin/vscanner
>  if $cmdret is above 1 then
>   fail "Virus infested - $cmdtext"
>  else if $cmdret is above 0 then
>   freeze "Filter suspicious - $cmdtext"
>       endif
>  endif
>     endif

>
> This could even be used in user filter files, although with more
> interesting effects :-)
>
>  Nigel.
> -- 
> [ - Opinions expressed are personal and may not be shared by VData - ]
> [ Nigel Metheringham                  Nigel.Metheringham@??? ]
> [ Phone: +44 1423 850000                         Fax +44 1423 858866 ]

>
>
>
>



---
Jason Robertson                
Network Analyst            
jason@???    
http://www.astroadvice.com