157 lines
6.6 KiB
Bash
Executable File
157 lines
6.6 KiB
Bash
Executable File
#!/bin/bash
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#
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# User Authentication and Destination Validation
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# ----------------------------------------------
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#
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# This script configures user authentication for Dovecot
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# and Postfix (which relies on Dovecot) and destination
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# validation by quering an Sqlite3 database of mail users.
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source setup/functions.sh # load our functions
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source /etc/mailinabox.conf # load global vars
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# ### User and Alias Database
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# The database of mail users (i.e. authenticated users, who have mailboxes)
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# and aliases (forwarders).
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db_path=$STORAGE_ROOT/mail/users.sqlite
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# Create an empty database if it doesn't yet exist.
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if [ ! -f $db_path ]; then
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echo Creating new user database: $db_path;
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echo "CREATE TABLE users (id INTEGER PRIMARY KEY AUTOINCREMENT, email TEXT NOT NULL UNIQUE, password TEXT NOT NULL, extra, privileges TEXT NOT NULL DEFAULT '');" | sqlite3 $db_path;
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echo "CREATE TABLE aliases (id INTEGER PRIMARY KEY AUTOINCREMENT, source TEXT NOT NULL UNIQUE, destination TEXT NOT NULL, permitted_senders TEXT);" | sqlite3 $db_path;
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fi
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# ### User Authentication
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# Have Dovecot query our database, and not system users, for authentication.
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sed -i "s/#*\(\!include auth-system.conf.ext\)/#\1/" /etc/dovecot/conf.d/10-auth.conf
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sed -i "s/#\(\!include auth-sql.conf.ext\)/\1/" /etc/dovecot/conf.d/10-auth.conf
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# Specify how the database is to be queried for user authentication (passdb)
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# and where user mailboxes are stored (userdb).
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cat > /etc/dovecot/conf.d/auth-sql.conf.ext << EOF;
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passdb {
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driver = sql
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args = /etc/dovecot/dovecot-sql.conf.ext
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}
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userdb {
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driver = sql
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args = /etc/dovecot/dovecot-sql.conf.ext
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}
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EOF
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# Configure the SQL to query for a user's metadata and password.
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cat > /etc/dovecot/dovecot-sql.conf.ext << EOF;
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driver = sqlite
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connect = $db_path
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default_pass_scheme = SHA512-CRYPT
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password_query = SELECT email as user, password FROM users WHERE email='%u';
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user_query = SELECT email AS user, "mail" as uid, "mail" as gid, "$STORAGE_ROOT/mail/mailboxes/%d/%n" as home FROM users WHERE email='%u';
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iterate_query = SELECT email AS user FROM users;
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EOF
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chmod 0600 /etc/dovecot/dovecot-sql.conf.ext # per Dovecot instructions
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# Have Dovecot provide an authorization service that Postfix can access & use.
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cat > /etc/dovecot/conf.d/99-local-auth.conf << EOF;
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service auth {
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unix_listener /var/spool/postfix/private/auth {
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mode = 0666
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user = postfix
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group = postfix
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}
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}
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EOF
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# And have Postfix use that service. We *disable* it here
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# so that authentication is not permitted on port 25 (which
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# does not run DKIM on relayed mail, so outbound mail isn't
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# correct, see #830), but we enable it specifically for the
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# submission port.
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management/editconf.py /etc/postfix/main.cf \
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smtpd_sasl_type=dovecot \
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smtpd_sasl_path=private/auth \
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smtpd_sasl_auth_enable=no
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# ### Sender Validation
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# We use Postfix's reject_authenticated_sender_login_mismatch filter to
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# prevent intra-domain spoofing by logged in but untrusted users in outbound
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# email. In all outbound mail (the sender has authenticated), the MAIL FROM
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# address (aka envelope or return path address) must be "owned" by the user
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# who authenticated. An SQL query will find who are the owners of any given
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# address.
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management/editconf.py /etc/postfix/main.cf \
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smtpd_sender_login_maps=sqlite:/etc/postfix/sender-login-maps.cf
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# Postfix will query the exact address first, where the priority will be alias
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# records first, then user records. If there are no matches for the exact
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# address, then Postfix will query just the domain part, which we call
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# catch-alls and domain aliases. A NULL permitted_senders column means to
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# take the value from the destination column.
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cat > /etc/postfix/sender-login-maps.cf << EOF;
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dbpath=$db_path
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query = SELECT permitted_senders FROM (SELECT permitted_senders, 0 AS priority FROM aliases WHERE source='%s' AND permitted_senders IS NOT NULL UNION SELECT destination AS permitted_senders, 1 AS priority FROM aliases WHERE source='%s' AND permitted_senders IS NULL UNION SELECT email as permitted_senders, 2 AS priority FROM users WHERE email='%s') ORDER BY priority LIMIT 1;
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EOF
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# ### Destination Validation
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# Use a Sqlite3 database to check whether a destination email address exists,
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# and to perform any email alias rewrites in Postfix.
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management/editconf.py /etc/postfix/main.cf \
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virtual_mailbox_domains=sqlite:/etc/postfix/virtual-mailbox-domains.cf \
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virtual_mailbox_maps=sqlite:/etc/postfix/virtual-mailbox-maps.cf \
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virtual_alias_maps=sqlite:/etc/postfix/virtual-alias-maps.cf \
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local_recipient_maps=\$virtual_mailbox_maps
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# SQL statement to check if we handle incoming mail for a domain, either for users or aliases.
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cat > /etc/postfix/virtual-mailbox-domains.cf << EOF;
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dbpath=$db_path
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query = SELECT 1 FROM users WHERE email LIKE '%%@%s' UNION SELECT 1 FROM aliases WHERE source LIKE '%%@%s'
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EOF
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# SQL statement to check if we handle incoming mail for a user.
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cat > /etc/postfix/virtual-mailbox-maps.cf << EOF;
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dbpath=$db_path
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query = SELECT 1 FROM users WHERE email='%s'
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EOF
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# SQL statement to rewrite an email address if an alias is present.
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#
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# Postfix makes multiple queries for each incoming mail. It first
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# queries the whole email address, then just the user part in certain
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# locally-directed cases (but we don't use this), then just `@`+the
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# domain part. The first query that returns something wins. See
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# http://www.postfix.org/virtual.5.html.
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#
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# virtual-alias-maps has precedence over virtual-mailbox-maps, but
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# we don't want catch-alls and domain aliases to catch mail for users
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# that have been defined on those domains. To fix this, we not only
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# query the aliases table but also the users table when resolving
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# aliases, i.e. we turn users into aliases from themselves to
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# themselves. That means users will match in postfix's first query
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# before postfix gets to the third query for catch-alls/domain alises.
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#
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# If there is both an alias and a user for the same address either
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# might be returned by the UNION, so the whole query is wrapped in
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# another select that prioritizes the alias definition to preserve
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# postfix's preference for aliases for whole email addresses.
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#
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# Since we might have alias records with an empty destination because
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# it might have just permitted_senders, skip any records with an
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# empty destination here so that other lower priority rules might match.
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cat > /etc/postfix/virtual-alias-maps.cf << EOF;
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dbpath=$db_path
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query = SELECT destination from (SELECT destination, 0 as priority FROM aliases WHERE source='%s' AND destination<>'' UNION SELECT email as destination, 1 as priority FROM users WHERE email='%s') ORDER BY priority LIMIT 1;
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EOF
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# Restart Services
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##################
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restart_service postfix
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restart_service dovecot
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