Sshd Configuration

---
name: sshd_configuration
description: Maintains the ansible/roles/sshd_configuration Ansible role that manages sshd_config options declaratively, resets config to RPM defaults, and validates every edit with sshd -t before applying, as part of the Linux SOE. Use when checking or fixing SSH daemon configuration.
---

# sshd_configuration

Maintains `ansible/roles/sshd_configuration/`. See `docs/ARCHITECTURE.md` for the shared
conventions (role layout, audit vs. remediate via `--check --diff`, safety
rules, branch + PR contribution workflow).

`ansible/roles/sshd_configuration/README.md` documents this role's full
configuration surface (every `defaults/main.yml` variable, with its
original inline comments, rendered as a single reference). Read it
before proposing or explaining how to configure this role — it
reflects the role's actual current defaults even if a variable summary
elsewhere in this file has drifted out of sync with the role.

## Policy & workload awareness

`docs/POLICY.md` and `docs/WORKLOAD.md` capture org-wide policy items and
the workloads this SOE actually hosts — either can gain a new or changed
item that this role should reflect. Before auditing, remediating, or
proposing a change, check whether either doc has changed more recently
than this role's own code:

```
git log -1 --format='%cI %h %s' -- docs/POLICY.md docs/WORKLOAD.md
git log -1 --format='%cI %h %s' -- ansible/roles/sshd_configuration/
```

If the docs' latest commit is newer than the role's, this role hasn't been
re-assessed against current policy/workload — read both files and judge
whether anything added or changed since is relevant to this domain:

- **Relevant** — propose a concrete change on a branch
  (`soe/sshd_configuration/policy-<short-desc>` or
  `soe/sshd_configuration/workload-<short-desc>`), same branch + PR workflow as
  any other role change (see "What to do" above and
  `docs/ARCHITECTURE.md`'s "Contribution workflow"). Don't wait to be
  asked.
- **Not relevant** — say so explicitly (e.g. "checked against
  `docs/POLICY.md` and `docs/WORKLOAD.md` as of `<date>`, nothing affecting
  this domain") rather than silently skipping the check.

This check is informational, not a gate — it runs alongside a normal
audit/remediate, never blocks one; surface the staleness note alongside
the normal output.

## What the role actually does

Encoded in `ansible/roles/sshd_configuration/defaults/main.yml`:

- `sshd_options` (dict, default empty) is enabled/updated; if
  `/etc/ssh/sshd_config.d` exists, changes are written exclusively into
  `0-ansible.conf` there rather than editing `sshd_config` directly.
  `ListenAddress` and `Match` blocks are only supported on RHEL 9+.
- `sshd_options_disable` (default empty) comments matching options out of
  every sshd config file found.
- **The role refuses to set `PermitRootLogin: 'no'` when the current
  connection is root without `sudo` (`SUDO_USER` not in the environment)** —
  a built-in guard against locking out the very connection making the change.
- `sshd_configuration_config_reset` (default `false`, RHEL 9+ only) resets
  RPM-provided files to shipped defaults — the role's own note: this can
  cause idempotency issues combined with `sshd_options_disable`, and only
  resets RPM-provided files, not others (suggests `files_copy` for older
  RHEL).
- `sshd_configuration_exclusive` (default `false`) removes unrecognized files
  from `sshd_config.d`, protected by `sshd_configuration_files_known`
  (defaults list several ComplianceAsCode/RHEL-provided filenames).
- Every config write is validated with `sshd -t -f %s` before being applied —
  same pattern as `motd_issue`'s sshd banner edit noted in
  `docs/ARCHITECTURE.md`.

This role is sourced from the myllynen/rhel-ansible-roles import
(see `git log -- ansible/roles/sshd_configuration`) rather than hand-authored for this
repo. Unlike the original reference domains (e.g. `timesync`, `usbguard_setup`),
it applies state declaratively via standard Ansible modules and does **not**
add its own `assert`-based drift checks on top — an audit here is exactly
what `--check --diff` reports from the underlying modules, nothing more.

## What to do

**Audit** (read-only, safe to run any time):

```
ansible-playbook ansible/configure_rhel.yml --tags sshd_configuration --check --diff
```

Summarize the diff output and any failed tasks in plain language.

**Remediate** (modifies the system — only after the user explicitly asks):
first summarize what will change from the `--check --diff` output, then run
the same command without `--check`:

```
ansible-playbook ansible/configure_rhel.yml --tags sshd_configuration
```

**Propose a change to the role itself**: never edit and commit directly. On a
branch named `soe/sshd_configuration/<short-desc>`, edit `ansible/roles/sshd_configuration/`, validate
locally (`--syntax-check`, `ansible-lint roles/sshd_configuration/`, and
`--check --diff` against a real/test host if available), then push and open a
PR titled `[sshd_configuration] <what changed>` with the `--check --diff` output in the
body. Then stop — a human reviews and merges; see `docs/ARCHITECTURE.md`'s
"Contribution workflow".

## Notes

- This role can lock out remote access if misused despite its guards (e.g.
  disabling password auth with no key-based access configured yet) — always
  review the `--check --diff` output for `PermitRootLogin`/`PasswordAuthentication`-type
  changes with extra care, and confirm out-of-band access exists before
  remediating a remote-only host.

## Wiring into the SOE

This role is in `configure_rhel_domains`'s default value in
`ansible/configure_rhel.yml` (see `.claude/skills/configure_rhel/SKILL.md`)
and has a row in `.claude/skills/soe/SKILL.md`'s domain table, so it runs as
part of both `ansible-playbook ansible/configure_rhel.yml --tags sshd_configuration ...` and
a full, untagged `ansible-playbook ansible/configure_rhel.yml` run. This repo
no longer uses `ansible/site.yml` as the baseline entrypoint — see
`docs/ARCHITECTURE.md`.