Nextcloud Mail Developer Documentation

Resetting the app

Connect to your database and run the following commands (oc_ is the default table prefix):

DELETE FROM oc_appconfig WHERE appid = 'mail';
DELETE FROM oc_migrations WHERE app = 'mail';
DROP TABLE oc_mail_accounts;
DROP TABLE oc_mail_aliases;
DROP TABLE oc_mail_coll_addresses;
DROP TABLE oc_mail_attachments;
DROP TABLE oc_mail_mailboxes;
DROP TABLE oc_mail_messages;
DROP TABLE oc_mail_recipients;
DROP TABLE oc_mail_classifiers;
DROP TABLE oc_mail_trusted_senders;
DROP TABLE oc_mail_tags;
DROP TABLE oc_mail_message_tags;
DROP TABLE oc_mail_provisionings;
DROP TABLE oc_mail_local_messages;

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Testing LDAP aliases provisioning

Testing the ldap aliases provisioning requires:

  1. LDAP service configured in Nextcloud
  2. IMAP service using LDAP for authentication
  3. A provisioning configuration for Mail

LDAP service configured in Nextcloud

The fastest way to setup Nextcloud with LDAP is https://github.com/juliushaertl/nextcloud-docker-dev.

It's still possible to integrate a ldap service into your own development setup with docker-compose.

ldap:
  image: osixia/openldap:1.5.0
  command: --copy-service --loglevel debug
  ports:
    - 50003:389
  volumes:
    - ./ldap:/container/service/slapd/assets/config/bootstrap/ldif/custom
  environment:
    LDAP_DOMAIN: planetexpress.com
    LDAP_BASE_DN: dc=planetexpress,dc=com

ldapadmin:
  image: osixia/phpldapadmin:0.9.0
  ports:
    - 50004:443
  environment:
    - PHPLDAPADMIN_LDAP_HOSTS=ldap

To have sample users we are using https://github.com/juliushaertl/nextcloud-docker-dev/tree/master/data/ldap. - Download the directory and save it in the same directory as docker-compose.yml. - Delete 99_others.ldif (otherwise you have a lot of additional test users). - Adjust the port mapping for your use case if necessary.

Run docker-compose to start ldap and ldapadmin. Visit ldapadmin at http://localhost:50004 (or whatever port you configured) and try to login with

ldapadmin overview

Next step is to configure our LDAP service in Nextcloud. - Login as administrator - Go to apps and enable "LDAP user and group backend" - Go to settings -> LDAP/AD integration

ldap in nextcloud - server

Click Test Base DN to test the configuration.

ldap in nextcloud - user

Click Verfiy settings and count users.

ldap in nextcloud - login attributes

ldap in nextcloud - groups

ldap in nextcloud - groups

IMAP service using LDAP for authentication

In a production environment we would configure our IMAP service to authenticate against the LDAP service. For our testing scenario it's sufficient to configure some LDAP accounts on the IMAP service.

imap:
  image: christophwurst/imap-devel:latest
  ports:
    - "25:25"
    - "143:143"
    - "993:993"
    - "4190:4190"
  environment:
    - MAILNAME=mail.domain.tld
    - MAIL_ACCOUNTS=admin@test.local,password 3268b904-582d-103b-83a5-c7ccb54ec103@planetexpress.com,bender 32657d7a-582d-103b-83a4-c7ccb54ec103@planetexpress.com,amy

Extend our docker-compose.yml and add the imap test image. Use the MAIL_ACCOUNTS environment variable to create test accounts for IMAP.

ldap in nextcloud - user management

3268b904-582d-103b-83a5-c7ccb54ec103@planetexpress.com is the username for the user in the LDAP directory. The username might be different on your setup. Please lookup the right values in the Nextcloud user management.

To create a IMAP account for Amy and Bender add to MAIL_ACCOUNTS.

32657d7a-582d-103b-83a4-c7ccb54ec103@planetexpress.com,amy 3268b904-582d-103b-83a5-c7ccb54ec103@planetexpress.com,bender

The password is (for our sample data) the display name in lowercase. Note that accounts are seperated by a space.

A provisioning configuration for Mail

ldap in nextcloud - provisioning configuration

The above configuration will query the mailAlias attribute for each user and use it to create and delete aliases.

Our sample data for LDAP does not contain mailAlias. To add one or more mailAliases to a user: - Visit ldapadmin - Expand dc=planetexpress,dc=com - Expand ou=people - Pick a user (e.g Bender) - Look for objectClass -> Click add value -> Select PostfixBookMailAccount -> Click Add new ObjectClass - Click Add new attribute -> Select mailAlias -> Enter rodriquez@planetexpress.com -> Press Enter -> Click Update Object

Now login to Nextcloud as Bender and go to Mail. See rodriquez@planetexpress.com as Alias in the Account settings for the provisoned mail account.

Generate self signed S/MIME CA and user certificates

You may use the following script to generate a CA and multiple user certificates. It has to be invoked with 2 parameters: the user name and the domain.

Example: Run the following command to generate a certificate for user@imap.localhost:

sh gen-smime-cert.sh user imap.localhost

You will be prompted for a password that is used to encrypt the PKCS12 (.p12) file.

The certificate and key will be placed in the current directory: - user@imap.localhost.crt: PEM encoded certificate - user@imap.localhost.key: PEM encoded private key - user@imap.localhost.crt: PKCS12 encoded certificate and private key for usage in desktop clients

gen-smime-cert.sh

#!/bin/sh

# Generate an S/MIME certificate for user@domain.

usage () {
    echo "Usage: $(basename "$0") <user> <domain>"
    echo 'This will generate an S/MIME certificate for user@domain.'
    echo 'The CA certificate is generated automatically if not present (ca.key, ca.crt).'
}

[ -z "$2" ] && usage && exit 1

common_name="$1"
email_address="$common_name"@"$2"

# Generate CA key and certificate if not present
if [ ! -f ca.key ] || [ ! -f ca.crt ]; then
    openssl genrsa -out ca.key 4096
    openssl req \
        -new \
        -x509 \
        -key ca.key \
        -out ca.crt \
        -days 3650 \
        -subj "/CN=0 S\\/MIME CA"
fi

# Generate client certificate
openssl genrsa -out "$email_address".key 4096
openssl req \
    -new \
    -x509 \
    -key "$email_address".key \
    -out "$email_address".crt \
    -CA ca.crt \
    -CAkey ca.key \
    -days 365 \
    -subj "/CN=$common_name/emailAddress=$email_address" \
    -set_serial 0x"$(openssl rand -hex 16)" \
    -addext basicConstraints=critical,CA:FALSE \
    -addext keyUsage=critical,digitalSignature,keyEncipherment \
    -addext "subjectAltName=email:$email_address"

# Export an encrypted PKCS12 (.p12) file
openssl pkcs12 \
    -export \
    -in "$email_address".crt \
    -inkey "$email_address".key \
    -out "$email_address".p12