From 5118f8d3394579a245b355c863c69410fe92e26e Mon Sep 17 00:00:00 2001
From: Guilhem Moulin <guilhem@fripost.org>
Date: Thu, 21 May 2020 01:35:28 +0200
Subject: dovecot-auth-proxy: replace directory traversal with LDAP lookups.
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This provides better isolation opportunity as the service doesn't need
to run as ‘vmail’ user.  We use a dedicated system user instead, and
LDAP ACLs to limit its access to the strict minimum.

The new solution is also more robust to quoting/escaping, and doesn't
depend on ‘home=/home/mail/virtual/%d/%n’ (we might use $entryUUID
instead of %d/%n at some point to make user renaming simpler).

OTOH we no longer lists users that have been removed from LDAP but still
have a mailstore lingering around.  This is fair.
---
 roles/IMAP/tasks/imap.yml | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

(limited to 'roles/IMAP/tasks')

diff --git a/roles/IMAP/tasks/imap.yml b/roles/IMAP/tasks/imap.yml
index 429854e..4a157af 100644
--- a/roles/IMAP/tasks/imap.yml
+++ b/roles/IMAP/tasks/imap.yml
@@ -18,6 +18,13 @@
         password=!
         state=present
 
+- name: Install Net::LDAP and Authen::SASL
+  apt: pkg={{ packages }}
+  vars:
+    packages:
+    - libnet-ldap-perl
+    - libauthen-sasl-perl
+
 - name: Copy dovecot auth proxy
   copy: src=usr/local/bin/dovecot-auth-proxy.pl
         dest=/usr/local/bin/dovecot-auth-proxy.pl
@@ -30,6 +37,15 @@
   tags:
    - sysctl
 
+- name: Create '_dovecot-auth-proxy' user
+  user: name=_dovecot-auth-proxy system=yes
+        group=nogroup
+        createhome=no
+        home=/nonexistent
+        shell=/usr/sbin/nologin
+        password=!
+        state=present
+
 - name: Copy dovecot auth proxy systemd unit files
   copy: src=etc/systemd/system/{{ item }}
         dest=/etc/systemd/system/{{ item }}
-- 
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