Files
selfpost/SECURITY.md
T
mixandClaude Opus 5.5 2cfd239d16
test / test (push) Canceled after 0s
docs: panel-dkim-signing stage 3 - the documents without OpenDKIM
architecture § OpenDKIM becomes § DKIM signing (keys, the selector table
and when it is rewritten, the two sockets, what is signed and the limits,
the old tree); the process table, start order, liveness, the mail-path
diagram, § Sender check, Persistence and the restore Resync follow the
code. security.md: the panel signs with the login's key, the keys are the
panel's alone, group selfpost and CAP_KILL as they are now; OpenDKIM's
accepted risks go; new ones: what sendmail(1) submits is signed as the
server, Sender: is signed but not judged (the owner's decision), and
go-milter keeps every header per session, so the signer's 1 MiB refusal
does not bound the library's copy. guide: Health, the container log's
dkim-signer lines, backups, the long-line limit, and upgrading to 2.8.0 -
with the rollback to 2.7.x: its start reads the queue as its own postfix
(uid 101) before it hands the queue over, so the hand-over by name is run
in the 2.7.x image first (measured on a copy of the test server's queue:
postsuper failed before, passed after). development, README, SECURITY,
product, the assumptions register's header: what left the image.
entrypoint.sh: a comment, the rollback note as the guide gives it. Plan
stage 3 lines ticked, roadmap 12/14.

Written by four agents, one document each, against a brief of what the
code does; reviewed here.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-16 01:56:56 +03:00

83 lines
3.6 KiB
Markdown

# Security policy
## Supported versions
SelfPost follows SemVer. Fixes are issued for the **latest minor release of the
1.x line** only; there is no backporting to earlier minors. Upgrade before
reporting if you are behind — the image tag is `ghcr.io/mixeme/selfpost:X.Y.Z`.
| Version | Supported |
|---|---|
| latest 1.x | yes |
| earlier 1.x | no — upgrade first |
| 0.x | no (pre-release) |
## Reporting a vulnerability
**Do not open a public issue.** Use GitHub's private vulnerability reporting:
the *Report a vulnerability* button under the repository's
[Security tab](https://github.com/mixeme/selfpost/security). If you cannot use
it, mail `public@mixeme.ru` instead.
Useful in a report: the image tag, the reverse proxy in front of the panel, the
steps to reproduce, and what an attacker gains. A relevant excerpt of
`mail.log` or the panel's system log helps; strip recipient addresses first.
**No response time is promised.** SelfPost is maintained by one person, and a
deadline that cannot be honoured is worse than none. Reports are read and
answered as soon as the maintainer is able; a fix ships in a patch release,
with the timeline agreed in the thread.
Disclosure is coordinated by request, not by demand: please hold public details
until a patch is out. If you get no reply, that is not a request for a
continued embargo — disclose at your own discretion. Reporters are credited in
the CHANGELOG unless they ask not to be.
## In scope
The relay's job is to accept authenticated mail from an application and hand it
to the internet as the operator's domain, and nothing else. Breaking that is in
scope:
- **Open relay** — mail accepted from an unauthenticated sender, or relayed for
a domain the sending application is not bound to
- **SASL bypass** — sending without valid credentials, or credential recovery
from anything the container exposes
- **Cross-domain access** — an application or a panel session reaching a domain
it was not granted
- **Secret disclosure** — DKIM private keys, the admin password hash, session
tokens, or backup encryption material leaking to an unauthorised party
- **Panel authentication and session flaws** — login bypass, session fixation,
CSRF on state-changing routes, privilege escalation
- **Rate-limit bypass** — evading either the Postfix-level backstop or the
per-domain and per-application limits
- **Container escape** or privilege escalation from the panel's unprivileged
user to root
## Out of scope
These are the operator's responsibility or accepted trade-offs, documented in
[docs/security.md](docs/security.md) and the
[operator guide](docs/guide.md):
- Host configuration the operator controls: a blocked port 25, a missing or
wrong PTR record, DNS records not published, a self-signed or expired
certificate on the reverse proxy
- Anything requiring the attacker to already have root on the host or write
access to the `./data` bind mount
- Missing hardening headers or TLS options on the reverse proxy — SelfPost
never terminates HTTPS itself
- Deliverability outcomes: mail rejected or filtered by a receiving provider is
a policy decision of that provider, not a defect
- Denial of service through sheer volume against a single-tenant relay
- Vulnerabilities in upstream Postfix, the Go libraries SelfPost builds on,
or the base image — report
those upstream; if SelfPost's configuration makes an upstream issue
exploitable when it otherwise would not be, that *is* in scope
## Reports we cannot act on
Automated scanner output with no demonstrated impact, and reports whose only
content is a version number compared against a CVE list, are closed without
investigation.