Security audit 2026-10-17, finding I3 (low), stage 4. No compose file set pids_limit: a fork bomb from a compromised panel or postfix had the host's pid space as its limit. Now 1024 for SelfPost - the plan said 512, but Postfix starts up to default_process_limit (100) processes per service, and a busy server runs three smtpd services, cleanup and smtp at once - 256 for nginx, Caddy, Traefik and rspamd, 64 for certbot. The comment that said root runs "very briefly" now says which root processes stay. e2e: checkPidsLimit reads /sys/fs/cgroup/pids.max in the container. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
78 lines
3.6 KiB
YAML
78 lines
3.6 KiB
YAML
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# Alternative reverse-proxy: nginx. PEM files land on the host exactly like the
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# Apache+certbot scenario — nginx and certbot are close cousins here, both
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# writing/reading plain PEM under /etc/letsencrypt.
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#
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# This is a FRAGMENT, not a full replacement for ../docker-compose.yml: it
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# adds an nginx + certbot pair and removes the panel's host port publish (nginx
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# takes over 80/443 and proxies to the panel over the compose network
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# instead). Merge it with the base file — run this from the deploy/ directory
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# (Compose resolves every relative path in both files against the directory of
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# the FIRST -f file, i.e. deploy/, which is why paths below are ./nginx/... -
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# docs.docker.com/compose/how-tos/multiple-compose-files/merge/: "Paths are
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# evaluated relative to the base file"):
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#
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# docker compose -f docker-compose.yml -f nginx/docker-compose.nginx.yml up -d
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#
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# First-run certificate issuance, before nginx has a certificate to serve -
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# run once, with port 80 free (certbot answers the challenge itself;
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# --webroot would need nginx already serving /.well-known). --entrypoint is
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# needed: the service's own entrypoint is the renewal loop below, an
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# `sh -c` that ignores any arguments given to `run`
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# (docs.docker.com/reference/compose-file/services/#entrypoint; assumptions
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# D-guide:301):
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# docker compose -f docker-compose.yml -f nginx/docker-compose.nginx.yml \
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# run --rm -p 80:80 --entrypoint certbot certbot certonly --standalone \
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# -d mail.example.com --email you@example.com --agree-tos --no-eff-email
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services:
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selfpost:
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ports: !override
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- "465:465"
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- "587:587"
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- "25:25"
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# No host publish for 8080 here: nginx reaches it over the compose
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# network at selfpost:8080 instead (see nginx.conf.example).
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volumes: !override
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- ./data:/data
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- .:/selfpost-deploy:ro
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# certs/ holds two links, fullchain.pem and privkey.pem, to
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# /etc/letsencrypt/live/mail.example.com/ - a path inside the
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# container: certbot's directory below is mounted there whole, because
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# its live/ files are relative links into archive/ (mounting live/ alone
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# left them pointing at nothing). docs/guide.md, "Reverse proxy", nginx.
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- ./certs:/etc/postfix/tls:ro
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- ./nginx/certbot-etc:/etc/letsencrypt:ro
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nginx:
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image: nginx:1.27
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restart: unless-stopped
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# A ceiling on processes and threads (security audit 2026-10-17, I3).
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pids_limit: 256
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depends_on:
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- selfpost
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ports:
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- "80:80"
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- "443:443"
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volumes:
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- ./nginx/nginx.conf.example:/etc/nginx/conf.d/selfpost.conf:ro
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- ./nginx/certbot-etc:/etc/letsencrypt:ro
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- ./nginx/certbot-www:/var/www/certbot:ro
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certbot:
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image: certbot/certbot:latest
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pids_limit: 64
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volumes:
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- ./nginx/certbot-etc:/etc/letsencrypt
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- ./nginx/certbot-www:/var/www/certbot
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# Renewal twice a day is certbot's own recommended cadence; it no-ops
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# until a certificate is within its renewal window.
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# (eff-certbot.readthedocs.io, User Guide, "Automated Renewals": the
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# sample cron runs "certbot renew" at 0 and 12 h; renew acts only on a
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# certificate near expiry.) The first certificate was issued --standalone
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# (see the top of this file), and certbot renews with the plugin it was
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# issued with "unless you specify other plugins or options" (same page,
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# "Renewing certificates") - by then nginx holds port 80 and serves the
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# webroot, so renewal names it; a renewal that succeeds with it saves it.
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entrypoint: sh -c 'trap exit TERM; while :; do certbot renew --webroot -w /var/www/certbot; sleep 12h & wait $${!}; done'
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