Files
selfpost/build/Dockerfile
T
mixandClaude Opus 5.5 9eddd49602
test / test (push) Canceled after 0s
audit 2c: findings of the two reviews
Technical review (Opus, 11 findings, 2 medium) and security review (Fable,
no high or medium) of 3c86280..HEAD. Both confirm the port gives
dkim_mail_parse()'s result on every input it parses, and that no line the
check passes is signed with another domain's key.

- F1 (medium): OpenDKIM's parser takes lines no mail program reads as one
  address - "ceo@bank.com:me@mine.com", "Name <ceo@bank.com:me@mine.com>",
  "<b@evil.com, a@mine.com>", "ceo@bank.com <me@mine.com>",
  "ceo@bank.com@mine.com" - and signs for the last while a lenient reader
  shows the first. The line must now also be one address in RFC 5322's
  grammar (net/mail, display names in any charset passed through), at the
  domain OpenDKIM signs for. A quoted display name may still hold anything.
- F2 (medium): the bindings were asked about OpenDKIM's form of the
  address, quotes and all, so "x"@mine.com passed for an application
  holding @mine.com while x@mine.com belonged to another. They are now
  asked about the reader's address, its local part unquoted, as Postfix
  holds the envelope's.
- F3 / security (low): Bindings.Allowed and DomainOf fold case in ASCII
  only: Postfix folds as Unicode (casefold.c, ICU), but every key and
  login the panel writes is ASCII, and the Unicode fold let the Kelvin sign
  pass for "k" (net/mail then refuses such a line on the domain test).
- F4 (low): a TERM between "postfix start-fg &" and "child=$!" is no longer
  lost: the wrapper stops Postfix as soon as the pid is known.
- F5 (low): for startsecs after a start any failed reload passed as "not
  running". postfix-reload is now build/postfix-reload.sh: exit 75 when
  master -t says no master runs, else exec postfix reload; RunOnce returns
  EndError with the status, and only 75 is taken as done. supervisor.State
  goes.
- F6 (low): crashexit spares postfix-reload too - a reload that could not
  be spawned is reported to whoever asked, not a reason to stop the
  container.
- F7 (low): a certs/ that is itself a link is resolved before the walk
  (filepath.WalkDir does not follow its root).
- F8 (low): at shutdown the tailer reads what is left of the rotated
  file before saving its place. Not changed: a refusal line still waiting
  on the old file at shutdown is not kept - the panel writes refused rows
  itself, only a kill loses one, and that window is the minute's grace.
- F9 (low): pct read as text - empty or unreadable is 100, the rest held
  to 0..100.
- F10 (low): the directory is synced after sasldb2's rename.
- F11 (low): POSTFIX_STARTSECS by expr, so "010" or "08" in
  MILTER_WAIT_TIMEOUT are decimal, not octal or an error.
- Security (low): pagehide also empties defaultValue - the input's value
  attribute and the textarea's text - not only .value. A sasldb2.new left
  by a killed panel is removed at start (entrypoint) and never archived.
  security.md says that links under certs/ are followed and by whom they
  can be placed.

Tests: sender check cases for F1 (four lines), F2 (a bound address
quoted, for its owner and for another), F3; EndError's state and status;
pct cases. architecture.md and CHANGELOG describe the reader rule. Stand
(2026-10-15, make e2e, exit 0); go vet and go test ./... pass on the
server (24 packages).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-15 09:17:33 +03:00

144 lines
6.9 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.
# (postfix 3.7.11-0+deb12u1, debian/templates: postfix/main_mailer_type and
# postfix/mailname are the questions the install asks.)
# What else arrives through Depends, and is used here: openssl, by
# ca-certificates ("Depends: openssl (>= 1.1.1)", packages.debian.org/bookworm/
# ca-certificates) - postfix-cert-reload.sh; python3, by supervisor (supervisor
# 4.2.5-1, debian/control, ${python3:Depends}) - crashexit.py. sasl2-bin brings
# saslpasswd2 and libsasl2-modules the PLAIN and LOGIN plugins; the sasldb
# auxprop plugin is in libsasl2-modules-db, a Depends of libsasl2-2
# (cyrus-sasl2 2.1.28+dfsg-10, debian/control and debian/*.install). db-util
# ships /usr/bin/db_dump (packages.debian.org/bookworm/amd64/db-util/filelist).
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).
# groupadd(8) refuses a --gid already in use, so a package that took 998 would
# fail this build rather than share the group.
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. The same membership is what lets the panel submit its
# own notifications with sendmail(1) - postdrop, too, is setgid and would fail
# to write the maildrop directory (internal/notify/mailer.go). It does not let
# the panel bypass any Postfix restriction that a local user does not already
# have through the world-executable sendmail.
# (Postfix 3.7.11, conf/postfix-files: postdrop and postqueue are
# root:$setgid_group 2755. Linux, Documentation/userspace-api/no_new_privs.rst:
# with no_new_privs, execve() no longer changes the gid for a setgid file.)
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-reload.sh /usr/local/bin/postfix-reload.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"]