Having the certificates inside the domain directory may cause some confusion,
as it's possible they're not for the same name (they should be for the MX we
serve as, not the domain itself).
So it's not a problem if we have domains with no certificates (we could be
their MX with another name), and we could have more than one certificate per
"domain" (if we act as MXs with different names).
So this patch moves the certificates out of the domains into a new certs/
directory, where we do a one-level deep lookup for the files.
While at it, change the names of the files to "fullchain.pem" and
"privkey.pem", which match the names generated by the letsencrypt client, to
make it easier to set up. There's no general convention for these names
anyway.
It's more convenient and in line with standard practice to fail RCPT TO if the
user does not exist.
This involves making the server and client aware of aliases, but it doesn't
end up being very convoluted, and simplifies other code.
This patch tidies up the Procmail courier:
- Move the configuration options to the courier instance, instead of using
global variables.
- Implement more useful string replacement options.
- Use exec.CommandContext for running the command with a timeout.
As a consequence of the first item, the queue now takes the couriers via its
constructor.
This patch adds a "data_dir" option, that chasquid will use to store
persistent data. It defaults to "/var/lib/chasquid" (for now, at least).
Users will come in subsequent patches.
This patch adds checks that verify:
- The envelope from must match the authenticated user. This prevents
impersonation at the envelope level (while still allowing bounces, of
course).
- If the destination is remote, then the user must have completed
authentication. This prevents unauthorized relaying.
The patch ends up adjusting quite a few tests, as they were not written
considering these restrictions so they have to be changed accordingly.
We want to be able to distinguish between connections for SMTP and connections
for submission, so we can make different policy decisions.
To do that, we first make the configuration aware of the different kinds of
addresses. This is done in this patch in a backwards-incompatible way, but at
this point in time it is ok to do so.
Then, we extend systemd's socket passing library to support socket naming, so
we can tell the different sockets apart. This is done via the
LISTEN_FDNAMES/FileDescriptorName mechanism.
And finally we make the server and connection types aware of the socket mode.
