enable starttls and generate self-signed certificate

.gitignore

@@ -1,2 +1,5 @@
 *~
 .*~
+ENV
+ENV.test
+tmp/

.woodpecker.yml

@@ -13,15 +13,14 @@ steps:
       dockerfile: Dockerfile
     when:
       - event: [push, tag]
-  public_build:
+  build:
     image: plugins/kaniko
     settings:
-      repo: wollud1969/exim-docker
+      repo: quay.io/wollud1969/exim-docker
       registry: quay.io
       tags: 
-        - quay.io/wollud1969/exim-docker/latest
-        - quay.io/wollud1969/exim-docker/${CI_COMMIT_SHA}
-        - quay.io/wollud1969/exim-docker/${CI_COMMIT_TAG}
+        - latest
+        - ${CI_COMMIT_TAG}
       username:
         from_secret: quay_username
       password:

Dockerfile

@@ -1,33 +1,28 @@
-FROM debian:bookworm
+FROM alpine:3.21.0
 
 LABEL Maintainer="Wolfgang Hottgenroth <woho@hottis.de>"
-LABEL ImageName=""
+LABEL ImageName="quay.io/wollud1969/exim-docker"
 
 # domain to be used in sender address of sent mails
 ENV LOCALMAILNAME=""
 # smarthost to send mail to
 ENV SMARTHOST=""
-# recipient addresses for root aliases, separate multiple addresses by space
-ENV ROOT=""
+ENV SMARTHOST_USER=""
+ENV SMARTHOST_PASS=""
 # ip addresses or networks to allow for relaying, separate multiple ones by semicolon
-ENV RELAYNETS=""
+ENV RELAYNETS="127.0.0.1/32"
 
-RUN \
-  apt update && \
-  apt upgrade -y --autoremove && \
-  apt install -y exim4-daemon-light ca-certificates curl && \ 
-  rm -rf /var/lib/apt/lists/*
+RUN apk add --no-cache exim m4 openssl
 
-COPY update-exim4.conf.tmpl /etc/exim4/
-COPY aliases.tmpl /etc/exim4/
-COPY adjust-config.sh /etc/exim4/
-COPY start.sh /etc/exim4/
+COPY exim.conf.m4 /etc/exim
+COPY start.sh /etc/exim
 
-WORKDIR /etc/exim4
+WORKDIR /etc/exim
 
 EXPOSE 25
 
 CMD [ "./start.sh" ]
+#CMD [ "/usr/bin/m4 exim.conf.m4 > exim.conf && /usr/sbin/exim -bd -q15m -v" ]
 
  
 

adjust-config.sh

@@ -1,15 +0,0 @@
-#!/bin/bash
-
-cat update-exim4.conf.tmpl \
-  | sed -e 's/%HOSTNAME%/'$HOSTNAME'/' \
-        -e 's#%RELAYNETS%#'$RELAYNETS'#' \
-        -e 's/%LOCALMAILNAME%/'$LOCALMAILNAME'/' \
-        -e 's/%SMARTHOST%/'$SMARTHOST'/' \
-  > update-exim4.conf.conf 
-cat aliases.tmpl \
-  | sed -e 's/%ROOT%/'"$ROOT"'/' \
-  > ../aliases && \
-newaliases
-
-/usr/sbin/update-exim4.conf -v
-

aliases.tmpl

@@ -1,14 +0,0 @@
-mailer-daemon: postmaster
-postmaster: root
-nobody: root
-hostmaster: root
-usenet: root
-news: root
-webmaster: root
-www: root
-ftp: root
-abuse: root
-noc: root
-security: root
-root: %ROOT%
-

examples/deploy.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+
+
+kubectl create secret generic smtp-secrets \
+  --dry-run=client \
+  -o yaml \
+  --save-config \
+  --from-literal=SMARTHOST="smtprelaypool.ispgateway.de" \
+  --from-literal=SMARTHOST_USER="pseudosmarthostuser@hottis.de" \
+  --from-literal=SMARTHOST_PASS="$SMARTHOST_PASSWORD" \
+  --from-literal=RELAYNETS=":10.0.0.0/8" | \
+kubectl apply -n system -f -
+
+kubectl apply -n system -f deploy.yml
+
+

examples/deploy.yml

@@ -0,0 +1,42 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: smtp
+  labels:
+    app: smtp
+  annotations:
+    secret.reloader.stakater.com/reload: smtp-secrets
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: smtp
+  template:
+    metadata:
+      labels:
+        app: smtp
+    spec:
+      containers:
+        - name: smtp
+          image: quay.io/wollud1969/exim-docker:0.2.2
+          envFrom:
+            - secretRef:
+                name: smtp-secrets
+          ports:
+            - containerPort: 25
+              protocol: TCP
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: smtp
+spec:
+  type: ClusterIP
+  selector:
+    app: smtp
+  ports:
+    - name: smtp
+      protocol: TCP
+      port: 25
+      targetPort: 25
+

examples/start-mailer.sh

@@ -0,0 +1,25 @@
+#!/bin/bash
+
+
+IMAGE=quay.io/wollud1969/exim-docker:0.0.9
+MAILER_NETWORK=mailer-network
+
+
+docker network inspect $MAILER_NETWORK > /dev/null || docker network create $MAILER_NETWORK
+
+
+if [ "$RELAYNETS" = "" ]; then
+  RELAYNETS=`docker network inspect $MAILER_NETWORK --format '{{ (index .IPAM.Config 0).Subnet }}'`
+fi
+
+
+docker run \
+  -d \
+  -e SMARTHOST=smarthost.example.com \
+  -e LOCALMAILNAME=example.com \
+  -e RELAYNETS=$RELAYNETS \
+  --network $MAILER_NETWORK \
+  --name mailer \
+  --restart always \
+  $IMAGE
+

exim.conf.m4

@@ -0,0 +1,67 @@
+dnl values
+define(`HOSTNAME', esyscmd(`echo -n $HOSTNAME'))dnl
+define(`LOCALMAILNAME', esyscmd(`echo -n $LOCALMAILNAME'))dnl
+define(`SMARTHOST', esyscmd(`echo -n $SMARTHOST'))dnl
+define(`SMARTHOST_USER', esyscmd(`echo -n $SMARTHOST_USER'))dnl
+define(`SMARTHOST_PASS', esyscmd(`echo -n $SMARTHOST_PASS'))dnl
+define(`RELAYNETS', esyscmd(`echo -n $RELAYNETS'))dnl
+
+ifelse(SMARTHOST, `', `
+errprint(`Error: SMARTHOST not set')
+m4exit(1)
+')
+
+ifelse(HOSTNAME, `', `
+errprint(`Error: HOSTNAME not set')
+m4exit(1)
+')
+
+dnl template for exim.conf
+
+primary_hostname = HOSTNAME
+
+acl_smtp_rcpt = acl_check_rcpt
+
+tls_certificate = /etc/exim/tls.crt
+tls_privatekey = /etc/exim/tls.key
+
+begin routers
+smarthost_route:
+  driver = manualroute
+  domains = *
+  transport = smarthost_smtp
+  route_list = * SMARTHOST
+
+begin transports
+smarthost_smtp:
+  driver = smtp
+  port = 25
+  multi_domain
+ifelse(SMARTHOST_USER, `', `', `dnl
+  hosts_require_auth = *
+')
+
+ifelse(SMARTHOST_USER, `', `', `
+begin authenticators
+plain:
+  driver = plaintext
+  public_name = PLAIN
+  client_send = ^SMARTHOST_USER^SMARTHOST_PASS
+
+login:
+  driver = plaintext
+  public_name = LOGIN
+  client_send = : SMARTHOST_USER : SMARTHOST_PASS
+')
+
+begin acl
+acl_check_rcpt:
+  accept
+    hosts = RELAYNETS
+  deny
+    message = "Relaying denied"
+
+ifelse(LOCALMAILNAME, `', `', `
+begin rewrite
+*@* ${1}@LOCALMAILNAME Ffrs
+')

readme.md

@@ -0,0 +1,56 @@
+# EXIM4 from Debian in a container
+
+This image can be used to deploy an MTA in a container and connect it to a smarthost to provide the 
+option to send mail from other containers without the need to configure the smarthost in each of them.
+
+## Configuration
+
+Four environment variables are used to configure the container:
+
+* `SMARTHOST`: The is the name of the smarthost. exim within this container will send all mail to this smarthost for further delivery. Make sure the smarthost accepts mail from this container without authentication.
+* `SMARTHOST_USER`: Login for smarthost. If no authentication is required, skip it.
+* `SMARTHOST_PASS`: Password for smarthost.
+* `LOCALMAILNAME`: The domain name which shall be used as the domain part of the sender address in every outgoing mail. If not required, skip it.
+* `RELAYNETS`: Networks exim in this container accepts for relaying. Separate multiple networks by semicolon.
+
+
+## Deployment
+
+Typically, don't expose the smtp port of this container to the default network of your Docker installation, otherwise it conflicts with a local MTA on the machine and it would be visible outside of the machine. Create a dedicated docker network, use that one as the default network for this container and connect other containers to that network. Afterwards, you can use the name of this container as smarthost address in the other containers.
+
+
+## Example start script
+
+```
+#!/bin/bash
+
+IMAGE=quay.io/wollud1969/exim-docker:0.2.2
+MAILER_NETWORK=mailer-network
+
+docker network create $MAILER_NETWORK || echo "mailer-network already exists"
+
+if [ "$RELAYNETS" = "" ]; then
+  RELAYNETS=`docker network inspect $MAILER_NETWORK --format '{{ (index .IPAM.Config 0).Subnet }}'`
+fi
+
+docker run \
+  -d \
+  -e SMARTHOST=smarthost.example.com \
+  -e LOCALMAILNAME=krohne.com \
+  -e RELAYNETS=$RELAYNETS \
+  --network $MAILER_NETWORK \
+  --name mailer \
+  --restart always \
+  $IMAGE
+```
+
+## Usage in other containers
+
+Connect other containers to the mailer network:
+
+```
+docker network connect mailer-network name_of_other_container
+```
+
+Now you can use the name of the mailer container, here `mailer` as smarthost name in that other container.
+

start.sh

@@ -1,5 +1,9 @@
-#!/bin/bash
+#!/bin/sh
 
-./adjust-config.sh
+openssl genpkey -algorithm RSA -out tls.key && \
+openssl req -new -key tls.key -out tls.csr -subj "/C=DE/CN=$HOSTNAME" && \
+openssl x509 -req -in tls.csr -signkey tls.key -out tls.crt -days 3650 && \
+chown exim tls.key tls.crt && \
+m4 exim.conf.m4 > exim.conf && \
 exim -bd -q15m -v
 

update-exim4.conf.tmpl

@@ -1,14 +0,0 @@
-dc_eximconfig_configtype='satellite'
-dc_other_hostnames='%HOSTNAME%'
-dc_local_interfaces='0.0.0.0'
-dc_readhost='%LOCALMAILNAME%'
-dc_relay_domains=''
-dc_minimaldns='false'
-dc_relay_nets='%RELAYNETS%'
-dc_smarthost='%SMARTHOST%'
-CFILEMODE='644'
-dc_use_split_config='false'
-dc_hide_mailname='true'
-dc_mailname_in_oh='true'
-dc_localdelivery='mail_spool'
-