systemd: extend CapabilityBoundingSet for auth_pam

Auth_pam will require audit writes or the connection will be rejected
as the plugin fails to initialize like:
  openvpn[1111]: sudo: unable to send audit message
  openvpn[1111]: sudo: pam_open_session: System error
  openvpn[1111]: sudo: policy plugin failed session initialization

See links from https://community.openvpn.net/openvpn/ticket/918 for
more.

auth_pam is a common use case and capabilties for it should be allowed
by the .service file.

Fixes: #918
Signed-off-by: Christian Ehrhardt <christian.ehrhardt@canonical.com>
Acked-by: David Sommerseth <davids@openvpn.net>
Message-Id: <20180829142715.417-2-christian.ehrhardt@canonical.com>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg17432.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>
(cherry picked from commit a564781cfd9912d0f755394d1fa610706d93e707)

diff --git a/distro/systemd/openvpn-server@.service.in b/distro/systemd/openvpn-server@.service.in
index a8366a04d3d0443bcbf709182822eb2f56141747..d1cc72cbd5d623583f5d50879596cef1f602e604 100644 (file)
--- a/distro/systemd/openvpn-server@.service.in
+++ b/distro/systemd/openvpn-server@.service.in
@@ -11,7 +11,7 @@ Type=notify
 PrivateTmp=true
 WorkingDirectory=/etc/openvpn/server
 ExecStart=@sbindir@/openvpn --status %t/openvpn-server/status-%i.log --status-version 2 --suppress-timestamps --config %i.conf
-CapabilityBoundingSet=CAP_IPC_LOCK CAP_NET_ADMIN CAP_NET_BIND_SERVICE CAP_NET_RAW CAP_SETGID CAP_SETUID CAP_SYS_CHROOT CAP_DAC_OVERRIDE
+CapabilityBoundingSet=CAP_IPC_LOCK CAP_NET_ADMIN CAP_NET_BIND_SERVICE CAP_NET_RAW CAP_SETGID CAP_SETUID CAP_SYS_CHROOT CAP_DAC_OVERRIDE CAP_AUDIT_WRITE
 LimitNPROC=10
 DeviceAllow=/dev/null rw
 DeviceAllow=/dev/net/tun rw