to facilitate migrations from/to other mail setups.
a domain can be added in "disabled" mode (or can be disabled/enabled later on).
you can configure a disabled domain, but incoming/outgoing messages involving
the domain are rejected with temporary error codes (as this may occur during a
migration, remote servers will try again, hopefully to the correct machine or
after this machine has been configured correctly). also, no acme tls certs will
be requested for disabled domains (the autoconfig/mta-sts dns records may still
point to the current/previous machine). accounts with addresses at disabled
domains can still login, unless logins are disabled for their accounts.
an account now has an option to disable logins. you can specify an error
message to show. this will be shown in smtp, imap and the web interfaces. it
could contain a message about migrations, and possibly a URL to a page with
information about how to migrate. incoming/outgoing email involving accounts
with login disabled are still accepted/delivered as normal (unless the domain
involved in the messages is disabled too). account operations by the admin,
such as importing/exporting messages still works.
in the admin web interface, listings of domains/accounts show if they are disabled.
domains & accounts can be enabled/disabled through the config file, cli
commands and admin web interface.
for issue #175 by RobSlgm
the imap & smtp servers now allow logging in with tls client authentication and
the "external" sasl authentication mechanism. email clients like thunderbird,
fairemail, k9, macos mail implement it. this seems to be the most secure among
the authentication mechanism commonly implemented by clients. a useful property
is that an account can have a separate tls public key for each device/email
client. with tls client cert auth, authentication is also bound to the tls
connection. a mitm cannot pass the credentials on to another tls connection,
similar to scram-*-plus. though part of scram-*-plus is that clients verify
that the server knows the client credentials.
for tls client auth with imap, we send a "preauth" untagged message by default.
that puts the connection in authenticated state. given the imap connection
state machine, further authentication commands are not allowed. some clients
don't recognize the preauth message, and try to authenticate anyway, which
fails. a tls public key has a config option to disable preauth, keeping new
connections in unauthenticated state, to work with such email clients.
for smtp (submission), we don't require an explicit auth command.
both for imap and smtp, we allow a client to authenticate with another
mechanism than "external". in that case, credentials are verified, and have to
be for the same account as the tls client auth, but the adress can be another
one than the login address configured with the tls public key.
only the public key is used to identify the account that is authenticating. we
ignore the rest of the certificate. expiration dates, names, constraints, etc
are not verified. no certificate authorities are involved.
users can upload their own (minimal) certificate. the account web interface
shows openssl commands you can run to generate a private key, minimal cert, and
a p12 file (the format that email clients seem to like...) containing both
private key and certificate.
the imapclient & smtpclient packages can now also use tls client auth. and so
does "mox sendmail", either with a pem file with private key and certificate,
or with just an ed25519 private key.
there are new subcommands "mox config tlspubkey ..." for
adding/removing/listing tls public keys from the cli, by the admin.
needed for upcoming changes, where (now) package admin needs to import package
store. before, because package store imports mox- (for accessing the active
config), that would lead to a cyclic import. package mox- keeps its active
config, package admin has the higher-level config-changing functions.
