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nixos/scripts/secrets/push-host-keys.sh
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beatzaplentyandClaude Sonnet 4.6 2743d664a5
Check NixOS configurations / eval-hosts (push) Successful in 10m22s
fix(push-host-keys): remove /dev/tty probe, plain read is sufficient
/dev/tty exists as a device node even without a controlling terminal,
so -r/-w tests pass but opening it fails. Plain 'read -r -s' from stdin
is enough: works interactively from a real terminal, and from a non-tty
context the caller should set SUDO_PASS in the environment instead.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-07-25 15:53:00 +10:00

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#!/usr/bin/env bash
# Pushes newly-generated SSH host keys from host-keys/ to already-running
# NixOS hosts, so they can decrypt sops secrets after a nixos-rebuild
# following scripts/secrets/sync-host-keys.sh --regenerate-all-keys.
#
# Before pushing any key, verifies that .sops.yaml and secrets/*.yaml are
# committed and pushed to the remote -- hosts rebuild from the remote Gitea
# flake, so recipient changes must land there before any rebuild, not just
# before the key push.
#
# push-host-keys.sh --all [--dry-run] [--skip-git-check]
# push-host-keys.sh <target> [--dry-run] [--skip-git-check]
#
# --all Push to every reachable managed host. Default when no
# target is given.
# <target> Push to one flake target only (e.g. lxc-server).
# --dry-run Print what would be done; write nothing.
# --skip-git-check Skip the commit/push check. Use only when the remote
# already has the current .sops.yaml/secrets/*.yaml.
#
# SSH: connects as SSH_USER@<hostname> (default: nixos, the user with the
# admin authorized key), then installs files via sudo -S (reads the sudo
# password from stdin). The password is prompted once at startup and reused
# for every host -- no PTY or terminal required on the remote side.
# Hosts are reached at their bare hostname (relies on LAN DNS/mDNS).
set -euo pipefail
repo_root="$(cd "$(dirname "$0")/../.." && pwd)"
keydir="${repo_root}/host-keys"
# shellcheck source=../env.sh
source "${repo_root}/scripts/env.sh"
# shellcheck source=../lib/nix-eval.sh
source "${repo_root}/scripts/lib/nix-eval.sh"
: "${SSH_USER:=nixos}"
SSH_OPTS=(-o StrictHostKeyChecking=no -o BatchMode=yes -o ConnectTimeout=5)
dry_run=0
skip_git_check=0
sudo_password=""
usage() {
cat <<EOF
Usage: $0 [--all | <target>] [--dry-run] [--skip-git-check]
--all Push to every reachable managed host. Default when no
target is given.
<target> Push to one flake target only (e.g. lxc-server).
--dry-run Print what would be done; write nothing.
--skip-git-check Skip the check that .sops.yaml/secrets/*.yaml are
committed and pushed to the remote repo.
Environment:
SSH_USER SSH username (default: nixos).
SUDO_PASS Sudo password (skips the interactive prompt; useful
when calling from another script).
EOF
}
# Prompt for the sudo password once; store it for all _do_push calls.
# Accepts SUDO_PASS from the environment to allow non-interactive callers.
prompt_sudo_password() {
[[ "$dry_run" -eq 1 ]] && return
if [[ -n "${SUDO_PASS:-}" ]]; then
sudo_password="$SUDO_PASS"
return
fi
read -r -s -p "sudo password for ${SSH_USER} on remote hosts: " sudo_password
echo >&2
}
locally_managed_hosts() {
for f in "${keydir}"/*_ssh_host_ed25519_key.pub; do
[[ -e "$f" ]] || continue
basename "$f" _ssh_host_ed25519_key.pub
done
}
# --- git state check/fix --------------------------------------------------
# Hosts rebuild from the remote Gitea flake:
# nixos-rebuild switch --flake "git+https://<gitea>/nixos.git#<target>"
# so .sops.yaml (updated recipients) and secrets/*.yaml (re-encrypted DEKs)
# must be committed and pushed before any rebuild can succeed. This check
# catches the common case where --regenerate-all-keys was just run but the
# resulting diff hasn't been committed/pushed yet.
ensure_remote_current() {
[[ "$skip_git_check" -eq 1 ]] && return
cd "$repo_root"
local dirty_unstaged dirty_staged
dirty_unstaged="$(git diff --name-only -- .sops.yaml secrets/ 2>/dev/null || true)"
dirty_staged="$(git diff --cached --name-only -- .sops.yaml secrets/ 2>/dev/null || true)"
if [[ -n "$dirty_unstaged" || -n "$dirty_staged" ]]; then
echo "Uncommitted changes in sops-managed files:"
[[ -n "$dirty_unstaged" ]] && sed 's/^/ (unstaged) /' <<<"$dirty_unstaged"
[[ -n "$dirty_staged" ]] && sed 's/^/ (staged) /' <<<"$dirty_staged"
echo
if [[ "$dry_run" -eq 1 ]]; then
echo "[dry-run] would prompt to commit .sops.yaml/secrets/ before continuing."
else
read -rp "Commit .sops.yaml + secrets/ now? [y/N]: " ans
if [[ "$ans" =~ ^[Yy]$ ]]; then
git add -- .sops.yaml secrets/
git commit -m "secrets: update recipients and re-encrypt for host key changes"
echo "Committed."
else
echo "Continuing with uncommitted changes -- the remote won't have the"
echo "updated recipients until you commit and push."
fi
fi
echo
fi
# Check if we're ahead of the remote tracking branch
local ahead
ahead="$(git rev-list --count '@{upstream}..HEAD' 2>/dev/null || echo "")"
if [[ -z "$ahead" ]]; then
echo "NOTE: no remote tracking branch found -- skipping push check."
echo " Ensure the remote has the current .sops.yaml/secrets/ before"
echo " triggering nixos-rebuild on any host."
echo
return
fi
if [[ "$ahead" -gt 0 ]]; then
echo "Local branch is ${ahead} commit(s) ahead of remote."
if [[ "$dry_run" -eq 1 ]]; then
echo "[dry-run] would prompt to push before continuing."
else
read -rp "Push to remote now? [y/N]: " ans
if [[ "$ans" =~ ^[Yy]$ ]]; then
git push
echo "Pushed."
else
echo "Continuing without pushing -- remember to push before running"
echo "nixos-rebuild on any of these hosts."
fi
fi
echo
fi
}
# --- key installation (shared) -------------------------------------------
_do_push() {
local hostname="$1" target="$2"
local keyfile="${keydir}/${target}_ssh_host_ed25519_key"
local pubfile="${keyfile}.pub"
if [[ "$dry_run" -eq 1 ]]; then
echo " [dry-run] would scp host-keys/${target}_ssh_host_ed25519_key{,.pub} to /tmp/"
echo " [dry-run] would: sudo -S install -m 0600/0644 to /etc/ssh/ and rm /tmp copies"
return
fi
# Upload to /tmp (writable as nixos, no privilege needed)
scp -o StrictHostKeyChecking=no \
"$keyfile" "${SSH_USER}@${hostname}:/tmp/push_ed25519_key"
scp -o StrictHostKeyChecking=no \
"$pubfile" "${SSH_USER}@${hostname}:/tmp/push_ed25519_key.pub"
# Install via sudo -S: the password is piped via herestring so no PTY is
# needed on either side. -p '' suppresses sudo's own prompt string.
ssh -o StrictHostKeyChecking=no "${SSH_USER}@${hostname}" \
"sudo -S -p '' bash -c '
install -m 0600 /tmp/push_ed25519_key /etc/ssh/ssh_host_ed25519_key
install -m 0644 /tmp/push_ed25519_key.pub /etc/ssh/ssh_host_ed25519_key.pub
rm -f /tmp/push_ed25519_key /tmp/push_ed25519_key.pub
echo \" [ok] host key installed\"
'" <<< "$sudo_password"
# Drop the stale known_hosts entry for this host (public key just changed)
ssh-keygen -R "$hostname" 2>/dev/null || true
echo " Done. Run nixos-rebuild switch on ${hostname} to activate."
}
# --- single named target --------------------------------------------------
push_target() {
local target="$1"
local keyfile="${keydir}/${target}_ssh_host_ed25519_key"
if [[ ! -f "$keyfile" ]]; then
echo "ERROR: host-keys/${target}_ssh_host_ed25519_key not found." >&2
echo " This target may not be locally managed (e.g. &${target} was" >&2
echo " registered from the host's real SSH key, not generated here)." >&2
exit 1
fi
local hostname
hostname="$(flake_target_hostname "$repo_root" "$target")"
if [[ -z "$hostname" ]]; then
echo "ERROR: cannot resolve hostname for '${target}' from the flake." >&2
exit 1
fi
echo "==> ${target} (→ ${hostname})"
if ! ssh "${SSH_OPTS[@]}" "${SSH_USER}@${hostname}" true 2>/dev/null; then
echo " SKIP: ${SSH_USER}@${hostname} unreachable."
return
fi
# Sanity-check that /etc/flake-target on the host agrees
local live_target
live_target="$(ssh "${SSH_OPTS[@]}" "${SSH_USER}@${hostname}" \
"cat /etc/flake-target 2>/dev/null || true")"
if [[ -n "$live_target" && "$live_target" != "$target" ]]; then
echo " WARN: host reports /etc/flake-target='${live_target}', not '${target}'."
echo " Pushing the key you specified (${target}) anyway."
fi
_do_push "$hostname" "$target"
}
# --- all managed hosts ----------------------------------------------------
# For each unique hostname derived from managed targets, SSHes in and reads
# /etc/flake-target to determine which key to push -- handles the case where
# multiple targets share a hostname (e.g. lxc-server and proxmox-server both
# resolve to "server"; only one is actually running).
push_all() {
mapfile -t managed < <(locally_managed_hosts)
if [[ "${#managed[@]}" -eq 0 ]]; then
echo "No managed keys in host-keys/ -- nothing to push."
return
fi
echo "Pushing to all reachable managed hosts..."
echo
declare -A seen_hostnames=()
local t hostname
for t in "${managed[@]}"; do
hostname="$(flake_target_hostname "$repo_root" "$t" 2>/dev/null || true)"
[[ -z "$hostname" ]] && continue
[[ -n "${seen_hostnames[$hostname]+x}" ]] && continue
seen_hostnames["$hostname"]=1
echo "==> checking ${hostname}"
if ! ssh "${SSH_OPTS[@]}" "${SSH_USER}@${hostname}" true 2>/dev/null; then
echo " SKIP: ${SSH_USER}@${hostname} unreachable."
continue
fi
# Ask the host which flake target it actually is
local live_target
live_target="$(ssh "${SSH_OPTS[@]}" "${SSH_USER}@${hostname}" \
"cat /etc/flake-target 2>/dev/null || true")"
if [[ -z "$live_target" ]]; then
echo " SKIP: no /etc/flake-target on host -- can't determine which key to push."
continue
fi
local live_keyfile="${keydir}/${live_target}_ssh_host_ed25519_key"
if [[ ! -f "$live_keyfile" ]]; then
echo " SKIP: host is '${live_target}' but no host-keys/${live_target}_... (hand-registered key, not managed here)."
continue
fi
echo " target: ${live_target}"
_do_push "$hostname" "$live_target"
done
}
# --- main -----------------------------------------------------------------
mode="all"
target_arg=""
extra_args=()
for arg in "$@"; do
case "$arg" in
--dry-run) dry_run=1 ;;
--skip-git-check) skip_git_check=1 ;;
--all) mode="all" ;;
-h|--help) usage; exit 0 ;;
--*) echo "Unknown option: $arg" >&2; usage >&2; exit 1 ;;
*) extra_args+=("$arg") ;;
esac
done
if [[ "${#extra_args[@]}" -gt 1 ]]; then
echo "ERROR: specify at most one target (or --all)." >&2
usage >&2; exit 1
elif [[ "${#extra_args[@]}" -eq 1 ]]; then
mode="single"
target_arg="${extra_args[0]}"
fi
[[ "$dry_run" -eq 1 ]] && { echo "[dry-run] no changes will be made"; echo; }
nix_extra_opts
ensure_remote_current
prompt_sudo_password
if [[ "$mode" == "single" ]]; then
push_target "$target_arg"
else
push_all
fi
echo
if [[ "$dry_run" -eq 1 ]]; then
echo "[dry-run] Nothing was changed. Re-run without --dry-run to apply."
else
echo "Key push complete. For each updated host, run nixos-rebuild switch to"
echo "apply the config and let sops-nix decrypt secrets with the new key."
fi