matrix-docker-ansible-deploy/roles/matrix-mailer/templates/systemd/matrix-mailer.service.j2
Slavi Pantaleev 316d653d3e Drop capabilities in containers
We run containers as a non-root user (no effective capabilities).

Still, if a setuid binary is available in a container image, it could
potentially be used to give the user the default capabilities that the
container was started with. For Docker, the default set currently is:
- "CAP_CHOWN"
- "CAP_DAC_OVERRIDE"
- "CAP_FSETID"
- "CAP_FOWNER"
- "CAP_MKNOD"
- "CAP_NET_RAW"
- "CAP_SETGID"
- "CAP_SETUID"
- "CAP_SETFCAP"
- "CAP_SETPCAP"
- "CAP_NET_BIND_SERVICE"
- "CAP_SYS_CHROOT"
- "CAP_KILL"
- "CAP_AUDIT_WRITE"

We'd rather prevent such a potential escalation by dropping ALL
capabilities.

The problem is nicely explained here: https://github.com/projectatomic/atomic-site/issues/203
2019-01-28 11:22:54 +02:00

25 lines
717 B
Django/Jinja

[Unit]
Description=Matrix mailer
After=docker.service
Requires=docker.service
[Service]
Type=simple
ExecStartPre=-/usr/bin/docker kill matrix-mailer
ExecStartPre=-/usr/bin/docker rm matrix-mailer
ExecStart=/usr/bin/docker run --rm --name matrix-mailer \
--log-driver=none \
--user={{ matrix_mailer_container_user_uid }}:{{ matrix_mailer_container_user_gid }} \
--cap-drop=ALL \
--network={{ matrix_docker_network }} \
--env-file={{ matrix_mailer_base_path }}/env-mailer \
--hostname={{ hostname_matrix }} \
{{ matrix_mailer_docker_image }}
ExecStop=-/usr/bin/docker kill matrix-mailer
ExecStop=-/usr/bin/docker rm matrix-mailer
Restart=always
RestartSec=30
[Install]
WantedBy=multi-user.target