Today, aliases parsing is too lax, silently ignoring most kinds of invalid
lines.
That behaviour can cause a lot of confusion when users think the aliases
are being parsed, and also cause problems when extending the syntax.
This patch fixes that problem by making aliases parsing return errors on
the invalid lines.
Unfortunately this will cause some previously-accepted files to now be
rejected, but it should be quite visible.
This patch implements support for aliases that contain '*' as the
destination user.
In that case, we replace it with the original user.
For example, `*: *@pond` will redirect `lilly@domain` to `lilly@pond`.
This is experimental for now, and marked as such in the documentation.
The semantics can be subtle, so we may need to adjust them later.
This patch makes chasquid log how many users, aliases and DKIM keys were
loaded for each domain.
This makes it easier to confirm changes, and troubleshoot problems
related to these per-domain configuration files.
This patch adds the embedded aliases file to the fuzz corpus, because it
is trivial to do so, and is a reasonable seed which will be naturally
adjusted over time as the package evolves (as it happened in recent
commits).
Today, when a user sets an alias with drop characters and/or suffixes,
those go unused, since we always "clean" addresses before alias
resolution.
This results in unexpected and surprising behaviour, and it's not
properly documented either.
This patch resolves this unexpected behaviour as follows:
- Drop characters are ignored, both at parsing time and at lookup time.
- Lookups are done including the suffixes first, and if that results in
no matches, they are retried without suffixes.
This results in aliases working more intuitively for the most common use
cases: of users wanting to have different aliases for specific suffixes,
and not having to care for drop characters.
Hooks can be used to get different behaviour if needed, since the first
lookup is done with the address as-is.
Thanks to znerol@ (lo+github@znerol.ch) for reporting this, and the
discussion on how to fix it, in
https://github.com/albertito/chasquid/issues/41.
Today, the parsing functions are stand-alone since they don't need
anything from the resolver.
But in future patches, that will change.
In anticipation of that, move those functions to be methods of the
resolver.
The aliases.Resolver.Exists function currently returns the "clean"
address (with the drop characters and suffixes removed), which is relied
upon in its only caller.
That, however, makes the logic more difficult to follow, hiding some
of the address manipulation behind what should be a read-only check.
So this patch reorganizes that code a little bit, removing the
"cleaning" of the address as part of Exists, and making it explicit when
needed instead.
This patch does not have any user-visible change in behaviour, it is
just internal reorganization.
This is in preparation for further patches which will improve the
handling of some aliases corner cases.
This patch changes several internal packages to receive and pass tracing
annotations, making use of the new tracing library, so we can have
better debugging information.
ioutil package was deprecated in Go 1.16, replace all uses with their
respective replacements.
This patch was generated with a combination of `gofmt -r`, `eg`, and
manually (for `ioutil.ReadDir`).
We've accumulated a few linter issues around comments and a couple of
variable names.
While none of them is major, this patch cleans them up so it's easier to
go through the linter output, and we can start being more strict about
it.
This patch implements support for catch-all aliases, where users can add
a `*: destination` alias. Mails sent to unknown users (or other aliases)
will not be rejected, but sent to the indicated destination instead.
Please see https://github.com/albertito/chasquid/issues/23 and
https://github.com/albertito/chasquid/pull/24 for more discussion and
background.
Thanks to Alex Ellwein (aellwein@github) for the alternative patch and
help with testing; and to ThinkChaos (ThinkChaos@github) for help with
testing.
This patch skips the resolution logic if the address is not local.
Today, the resolution logic handles that case transparently, and returns
the original email address, so this should be a no-op.
However, having an explicit early check makes the resolution logic more
robust, and will simplify future patches.
Note this also means that the `alias-resolve` hook is no longer run for
non-local aliases, which should also help simplify their implementation.
The right-hand side addresses of an alias should be normalized, to
maintain the internal invariant that we always deal with normalized
addresses.
Otherwise, strange situations may arise, such as the same domain having
two different domaininfo structures depending on case.
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.
aliases databases can be very useful, so this patch adds a package to parse
and resolve aliases.
It uses an existing, well known and widely used format for aliases, although
it doesn't necessarily match 100% any existing implementation at the moment.
