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selfpost/build/Dockerfile
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mixandClaude Opus 5.5 dd0fefdcb7 backup: the panel's archive is the command's, private key included
Owner, 2026-10-11: the private key is needed, and a backup from the
panel and one from the console have to be the same.

The commit that made the panel's backup work skipped a file under
certs/ the panel could not open - on the test server the private key,
which the certificate hook leaves to root and Postfix's group. That gave
an archive with a certificate and no key, and two kinds of archive.

- Params.Unprivileged is gone. Nothing is left out on account of who
  makes the archive; the queue is out for everyone (previous commit).
- When the panel cannot read a file under certs/, backup.Check says so
  before the download and the panel refuses with what to do on the host:
  chgrp 998 certs/privkey.pem && chmod 640. backup.UnreadableCert tells
  that case from any other failure.
- 998 is the container's selfpost group, which holds the panel and
  Postfix. Its id was whatever groupadd gave; the Dockerfile now fixes
  it at the value it has always had, because an operator addresses it
  by number from the host.
- Guide: method 1 is the same archive as method 2, with the permission
  the key needs and a note for whatever renews the certificate. Help and
  the box follow the design commit before this one.
- e2e: the restore scenario first makes the key unreadable and expects
  the refusal naming the file and the way out, then takes the backup and
  expects the key in it; nothing is put back by hand before the restart.

  go vet ./internal/backup/ ./internal/web/handlers/: ok
  go test ./internal/backup/ ./cmd/... ./internal/web/...: ok
  make e2e on the test server: ok

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-11 20:43:10 +03:00

126 lines
5.7 KiB
Docker

# syntax=docker/dockerfile:1
#
# SelfPost — single Debian-slim image running postfix + opendkim + panel under
# supervisord. Build from the repository root:
#
# docker build -f build/Dockerfile -t selfpost:dev --build-arg VERSION=dev .
# ---- build stage -------------------------------------------------------------
FROM golang:1.26-bookworm AS build
WORKDIR /src
# Version stamped into both binaries; MUST match the image tag.
ARG VERSION=dev
# Module metadata first for layer caching.
COPY go.mod go.sum ./
RUN go mod download
COPY cmd ./cmd
COPY internal ./internal
ENV CGO_ENABLED=0
RUN go vet ./... \
&& go build -trimpath \
-ldflags "-X github.com/mixeme/selfpost/internal/buildinfo.Version=${VERSION}" \
-o /out/panel ./cmd/panel \
&& go build -trimpath \
-ldflags "-X github.com/mixeme/selfpost/internal/buildinfo.Version=${VERSION}" \
-o /out/selfpost-backup ./cmd/selfpost-backup
# ---- runtime stage -----------------------------------------------------------
FROM debian:bookworm-slim AS runtime
ENV DEBIAN_FRONTEND=noninteractive
# Preseed Postfix so its install is non-interactive and yields a working
# main.cf. The real relay configuration is generated by the panel.
RUN echo "postfix postfix/mailname string localhost" | debconf-set-selections \
&& echo "postfix postfix/main_mailer_type string Internet Site" | debconf-set-selections \
&& apt-get update \
&& apt-get install -y --no-install-recommends \
postfix \
opendkim \
opendkim-tools \
sasl2-bin \
libsasl2-modules \
db-util \
supervisor \
logrotate \
ca-certificates \
curl \
&& rm -rf /var/lib/apt/lists/*
# Unprivileged user for the panel process.
RUN useradd --system --no-create-home --shell /usr/sbin/nologin panel
# Shared group bridging the unprivileged services: the panel generates
# per-domain DKIM keys, application SASL accounts (sasldb2) and the Postfix
# sender map, while OpenDKIM and Postfix (different users) must read them.
# Membership in this group — plus setgid dirs under /data (set up in
# entrypoint.sh) — lets OpenDKIM read the panel-owned keys and lets Postfix read
# the sasldb2/sender map, and lets the panel reach the supervisor control socket
# to signal OpenDKIM/Postfix reloads without any process running as root.
# The id is fixed, and it is the one the group has always had: an operator
# gives the TLS private key on the host to this group by number, so that the
# panel can put it into a full backup (guide § Taking a full backup).
RUN groupadd --system --gid 998 selfpost \
&& usermod -aG selfpost panel \
&& usermod -aG selfpost opendkim \
&& usermod -aG selfpost postfix
# The panel reads the mail queue with `postqueue -p` (and the status page's
# queue card). postqueue is setgid postdrop, which normally gives it the group
# needed to reach Postfix's showq socket — but the documented deployment runs
# with `no-new-privileges`, which disables setgid transitions, so the panel
# would always see "Permission denied". Making `panel` a real member of postdrop
# grants the same access without relying on a setgid escalation the hardening
# deliberately forbids. postdrop membership is read-side only: it does not let
# the panel bypass any Postfix restriction that a local user does not already
# have through the world-executable sendmail.
RUN usermod -aG postdrop panel
# Runtime directories: milter sockets and the consolidated persistent root.
RUN mkdir -p /run/opendkim /run/selfpost /data \
&& chown opendkim:opendkim /run/opendkim \
&& chown panel:panel /run/selfpost /data
COPY --from=build /out/panel /usr/local/bin/panel
COPY --from=build /out/selfpost-backup /usr/local/bin/selfpost-backup
# Licence text shipped with the image (AGPL-3.0 conveyance). The panel also
# serves the same text at /license from an embedded copy. OFL.txt is the SIL
# Open Font License 1.1 that must travel with the IBM Plex WOFF2 files
# embedded in the panel binary (NOTICE).
COPY --chmod=0644 LICENSE NOTICE /usr/share/doc/selfpost/
COPY --chmod=0644 internal/web/view/static/OFL.txt /usr/share/doc/selfpost/OFL.txt
# File modes are pinned here so a build context copied from a checkout without
# POSIX permissions (e.g. Windows tar sync) cannot land group-writable config
# that logrotate would silently ignore — see docs/development.md § Building
# binaries and the image.
COPY --chmod=0644 build/opendkim.conf /etc/opendkim.conf
COPY --chmod=0644 build/logrotate-mail.conf /etc/logrotate.d/mail
COPY --chmod=0755 build/postfix-wrapper.sh /usr/local/bin/postfix-wrapper.sh
COPY --chmod=0755 build/postfix-config.sh /usr/local/bin/postfix-config.sh
COPY --chmod=0755 build/postfix-cert-reload.sh /usr/local/bin/postfix-cert-reload.sh
COPY --chmod=0755 build/logrotate-loop.sh /usr/local/bin/logrotate-loop.sh
COPY --chmod=0755 build/crashexit.py /usr/local/bin/crashexit.py
COPY --chmod=0755 build/entrypoint.sh /usr/local/bin/entrypoint.sh
COPY --chmod=0644 build/supervisord.conf /etc/supervisor/supervisord.conf
# Published submission ports: 465 (smtps, primary) and 587 (submission, optional),
# inbound SMTP on 25 when INBOUND_RELAY_ENABLE=true, plus the panel on 8080.
# Outbound delivery dials remote MXs on 25 as a client even when inbound is off.
EXPOSE 8080 465 587 25
# Liveness probe: panel HTTP plus mail-path processes (opendkim, panel, postfix).
# Does not verify TLS, DNS, or end-to-end delivery — see docs/guide.md Operations.
HEALTHCHECK --interval=30s --timeout=5s --start-period=90s --retries=3 \
CMD curl -fsS http://127.0.0.1:8080/healthz || exit 1
# The entrypoint fixes /data ownership (bind mount) as root, then execs
# supervisord, which becomes PID 1 and owns process supervision.
ENTRYPOINT ["/usr/local/bin/entrypoint.sh"]