### Hostux
###  2022-06-18 Original default configuration file with changes necessary to run it in Docker
###  2024-03-16 Adapted configuration file from https://raw.githubusercontent.com/foxcpp/maddy/master/maddy.conf.docker


# Suitable for small-scale deployments. Uses its own format for local users DB,
# should be managed via maddy subcommands.
#
# See tutorials at https://maddy.email for guidance on typical
# configuration changes.

# ----------------------------------------------------------------------------
# Base variables

$(hostname) = {env:MADDY_HOSTNAME}
$(primary_domain) = {env:MADDY_DOMAIN}
$(local_domains) = $(primary_domain) {env:HOSTUX_LOCAL_DOMAINS}

tls file /certs/live/$(hostname)/fullchain.pem /certs/live/$(hostname)/privkey.pem

# ----------------------------------------------------------------------------
# Local storage & authentication

# pass_table provides local hashed passwords storage for authentication of
# users. It can be configured to use any "table" module, in default
# configuration a table in SQLite DB is used.
# Table can be replaced to use e.g. a file for passwords. Or pass_table module
# can be replaced altogether to use some external source of credentials (e.g.
# PAM, /etc/shadow file).
#
# If table module supports it (sql_table does) - credentials can be managed
# using 'maddy creds' command.

auth.external hostux_auth {
    helper /bin/maddy-hostux-check-password
    perdomain yes
    domains $(local_domains)
}

# imapsql module stores all indexes and metadata necessary for IMAP using a
# relational database. It is used by IMAP endpoint for mailbox access and
# also by SMTP & Submission endpoints for delivery of local messages.
#
# IMAP accounts, mailboxes and all message metadata can be inspected using
# imap-* subcommands of maddy.

storage.imapsql local_mailboxes {
    driver sqlite3
    dsn imapsql.db
}

# ----------------------------------------------------------------------------
# SMTP endpoints + message routing

hostname $(hostname)

table.chain local_rewrites {
    optional_step regexp "(.+)\+(.+)@(.+)" "$1@$3"
    optional_step static {
        entry postmaster postmaster@$(primary_domain)
    }
}

table.chain hostux_rewrites {
    optional_step regexp "(.+)\+(.+)@(.+)" "$1@$3"
    optional_step sql_query {
        driver sqlite3
        dsn {env:HOSTUX_EMAIL_DATABASE_SQLITE}
        lookup "SELECT aliasTo_emailAddress FROM email-aliases WHERE emailAlias = $1"
    }
}

table.sql_query hostux_destinations {
    driver sqlite3
    dsn {env:HOSTUX_EMAIL_DATABASE_SQLITE}
    lookup "SELECT emailAddress AS address FROM `email-addresses`
            WHERE address = $1
            UNION
            SELECT emailAlias AS address FROM `email-aliases`
            WHERE address = $1"
}

msgpipeline local_routing {
    # Insert handling for special-purpose local domains here.
    # e.g.
    # destination lists.example.org {
    #     deliver_to lmtp tcp://127.0.0.1:8024
    # }

    check {
        rspamd {
            api_path {env:RSPAMD_SERVER}
        }
    }

    destination postmaster $(local_domains) {
        modify {
            replace_rcpt &local_rewrites
        }

        deliver_to &local_mailboxes
    }
    destination_in hostux_destinations {
        modify {
            replace_rcpt &hostux_rewrites
        }

        deliver_to &local_mailboxes
    }

    default_destination {
        reject 550 5.1.1 "User doesn't exist"
    }
}

smtp tcp://0.0.0.0:25 {
    limits {
        # Up to 20 msgs/sec across max. 10 SMTP connections.
        all rate 20 1s
        all concurrency 10
    }

    dmarc yes
    check {
        require_mx_record
        dkim
        spf
    }

    source $(local_domains) {
        reject 501 5.1.8 "Use Submission for outgoing SMTP"
    }
    source_in hostux_destinations {
        reject 501 5.1.8 "Use Submission for outgoing SMTP"
    }
    default_source {
        destination postmaster $(local_domains) {
            deliver_to &local_routing
        }
        default_destination {
            reject 550 5.1.1 "User doesn't exist"
        }
    }
}

submission tls://0.0.0.0:465 tcp://0.0.0.0:587 {
    limits {
        # Up to 50 msgs/sec across any amount of SMTP connections.
        all rate 50 1s
    }

    auth &hostux_auth

    source $(local_domains) {
        check {
            authorize_sender {
                prepare_email &local_rewrites
                user_to_email identity
            }
        }

        destination postmaster $(local_domains) {
            deliver_to &local_routing
        }
        default_destination {
            modify {
                dkim $(primary_domain) $(local_domains) default
            }
            deliver_to &remote_queue
        }
    }
    source_in hostux_destinations {
        check {
            authorize_sender {
                prepare_email &hostux_rewrites
                user_to_email identity
            }
        }

        destination postmaster $(local_domains) {
            deliver_to &local_routing
        }
        destination_in hostux_destinations {
            deliver_to &local_routing
        }

        default_destination {
            # TODO: rspamd milter w/ DKIM signing
            #modify {
            #    dkim $(primary_domain) $(local_domains) default
            #}
            deliver_to &remote_queue
        }
    }

    default_source {
        reject 501 5.1.8 "Non-local sender domain"
    }
}

target.remote outbound_delivery {
    limits {
        # Up to 20 msgs/sec across max. 10 SMTP connections
        # for each recipient domain.
        destination rate 20 1s
        destination concurrency 10
    }
    mx_auth {
        dane
        mtasts {
            cache fs
            fs_dir mtasts_cache/
        }
        local_policy {
            min_tls_level encrypted
            min_mx_level none
        }
    }
}

target.queue remote_queue {
    target &outbound_delivery

    autogenerated_msg_domain $(primary_domain)
    bounce {
        destination postmaster $(local_domains) {
            deliver_to &local_routing
        }
        destination_in hostux_destinations {
            deliver_to &local_routing
        }
        default_destination {
            reject 550 5.0.0 "Refusing to send DSNs to non-local addresses"
        }
    }
}

# ----------------------------------------------------------------------------
# IMAP endpoints

imap tls://0.0.0.0:993 tcp://0.0.0.0:143 {
    auth &hostux_auth
    storage &local_mailboxes
}