On 2013-03-31 at 00:20 -1000, J. Nick Koston wrote:
> I was actually able to get the force_command approach working after
> doing some more digging into exim guts to understand how things work a
> bit better. Its a much more simple approach.
*phew* I wasn't crazy to suggest it then. :)
> https://github.com/bdraco/exim/commit/force_command
>
> Please let me know what else you would like me to do to prepare this.
As things stand, I think you've invalidated our security guarantees
about argument-by-argument expansion. Also, you do the expansion before
$1 and friends are set up.
I suspect that the cleaner solution is to give a 'flags' parameter to
the `set_up_shell_command()` function call, then if force_command is
set, include a FLAG_VALUE or'd into the flags parameter which says to
treat $address_pipe specially, needing to be split apart into multiple
parameters.
This way, expansion occurs in the normal place, and you have one
special-case piece of logic, which can be documented in "29.3 How the
command is run" too, noting that if force_command is set and the command
came from a router, then command is evaluated and $address_pipe is split
up and is *not* held to one option, like everything else.
This minimises the impact, avoids expanding the string in different
places, with different variables already set up, and avoids quotes and
backslashes in data resulting from expansion ending up creating new
parameters.
Regards,
-Phil
