hyperhive/nix/modules/hive-tls.nix

176 lines
7.7 KiB
Nix

{
lib,
config,
pkgs,
...
}:
let
cfg = config.services.hyperhive.tls;
hyperhiveCfg = config.services.hyperhive;
gatewayCfg = config.services.hyperhive.gateway;
domain = hyperhiveCfg.domain;
# The host-managed hive CA is the trust anchor for self-signed mode.
# It is only stood up when the gateway actually serves a self-signed
# cert: the gateway must be in self-signed mode. `domain` is required
# (asserted in hive-network.nix), so the leaf SANs always have a
# domain to derive from. The self-signed condition is the gateway
# module's single source of truth (`gateway.useSelfSigned`): true when
# neither an operator cert (`tls.certDir`) nor ACME is set.
active = hyperhiveCfg.enable && gatewayCfg.useSelfSigned;
in
{
# Host-side TLS trust root for the self-signed gateway mode.
#
# `gateway.selfSignedTls` historically generated a *bare* self-signed
# leaf inside the gateway container at first boot. A bare leaf is its
# own trust anchor, so every regeneration is a new anchor and every
# consumer (agents, federation peers) would have to re-trust on each
# rotation — and a runtime-generated, in-container cert can't be wired
# into an agent's build-time trust store at all.
#
# This module moves the anchor to a long-lived **hive CA** held on the
# host. The gateway serves a **leaf** signed by that CA (via the
# existing `tls.certDir` bind-mount path); agents and federation peers
# trust the *CA* once, and leaf rotation never re-breaks them. See
# `docs/gateway.md` ("Self-signed TLS") and issue-tracker discussion of
# agent web-UI reachability.
options.services.hyperhive.tls = {
stateDir = lib.mkOption {
type = lib.types.str;
default = "/var/lib/hive-tls";
description = ''
Host directory holding the hive CA + gateway leaf cert for the
self-signed gateway mode. `ca.pem` (the anchor agents and
federation peers trust), `ca-key.pem` (0600, never leaves the
host), `gateway.pem` / `gateway-key.pem` (the leaf the gateway
container bind-mounts and nginx serves). Persistent so the CA
survives reboots re-deriving it would re-break every consumer.
'';
};
caValidityDays = lib.mkOption {
type = lib.types.int;
default = 7300;
description = ''
Validity window of the hive CA in days (default ~20y). Kept long
and well beyond `leafValidityDays` so the CA outlives many leaf
rotations the whole point of the CA is to be a stable anchor
that consumers trust once. The CA is regenerated only if missing
or already expired.
'';
};
leafValidityDays = lib.mkOption {
type = lib.types.int;
default = 30;
description = ''
Validity window of the gateway leaf cert in days (default 30).
Short-lived by design ahead of the CA/Browser-Forum's move
toward ~47-day max lifetimes which bounds the blast radius of a
leaf-key compromise. The leaf is re-signed by the (stable) CA
when it is missing or near expiry; because it shares the CA
anchor, a rotation does not disturb consumer trust. Agents and
federation peers validate against the CA, not browser CA/B-forum
limits. NOTE: at this short a window the re-sign must run more
often than the leaf lifetime. Today `hive-tls-ca` re-signs at
service activation (boot/rebuild) only there is no periodic
re-sign timer yet so a hive that does not reboot within the
validity window would let the leaf expire. Keep that in mind (or
add a re-sign timer) when running a hive that stays up for long
stretches without a rebuild.
'';
};
};
config = lib.mkIf active {
# Generate (and rotate) the hive CA + gateway leaf before the gateway
# container starts. Idempotent: the CA is created once and reused; the
# leaf is re-signed on expiry under the same CA so the anchor is stable.
systemd.services.hive-tls-ca = {
description = "Generate hive CA + gateway leaf TLS cert (self-signed mode)";
wantedBy = [ "multi-user.target" ];
# Gateway nginx reads the leaf from the bind-mount, so the cert must
# exist before the container starts. Declarative nixos-containers are
# instances of the `container@.service` template.
before = [ "container@hive-gateway.service" ];
requiredBy = [ "container@hive-gateway.service" ];
path = [ pkgs.openssl ];
serviceConfig = {
Type = "oneshot";
RemainAfterExit = true;
UMask = "0077";
# Pin the journal identity (else it's the `script` store-path wrapper).
SyslogIdentifier = "hive-tls-ca";
};
script = ''
set -euo pipefail
d=${lib.escapeShellArg cfg.stateDir}
install -d -m 0755 "$d"
ca="$d/ca.pem"
cak="$d/ca-key.pem"
leaf="$d/gateway.pem"
leafk="$d/gateway-key.pem"
# --- CA: generate once, reuse across leaf rotations. Regenerate
# only if missing or already expired (checkend 0). A new CA means
# every consumer must re-trust, so the leaf is dropped to force a
# re-sign under the fresh CA.
if [ ! -s "$ca" ] || [ ! -s "$cak" ] \
|| ! openssl x509 -in "$ca" -noout -checkend 0 >/dev/null 2>&1; then
echo "generating fresh hive CA at $ca"
openssl req -x509 -newkey rsa:4096 -nodes -sha256 \
-days ${toString cfg.caValidityDays} \
-keyout "$cak" -out "$ca" \
-subj "/CN=hive-ca ${domain}" \
-addext "basicConstraints=critical,CA:TRUE,pathlen:0" \
-addext "keyUsage=critical,keyCertSign,cRLSign"
chmod 0600 "$cak"
chmod 0644 "$ca"
rm -f "$leaf" "$leafk"
fi
# --- Leaf: (re)sign when missing or within 30 days of expiry,
# always under the current (stable) CA.
if [ ! -s "$leaf" ] || [ ! -s "$leafk" ] \
|| ! openssl x509 -in "$leaf" -noout -checkend 2592000 >/dev/null 2>&1; then
echo "signing fresh gateway leaf at $leaf"
csr="$(mktemp "$d/gateway.csr.XXXXXX")"
ext="$(mktemp "$d/leaf.ext.XXXXXX")"
trap 'rm -f "$csr" "$ext"' EXIT
openssl req -newkey rsa:4096 -nodes -sha256 \
-keyout "$leafk" -out "$csr" \
-subj "/CN=${domain}"
# printf (not a heredoc) so the ext-file lines carry no leading
# whitespace once nix has stripped the indented-string indent.
{
printf 'subjectAltName=DNS:%s,DNS:forge.%s,DNS:matrix.%s,DNS:*.%s\n' \
${lib.escapeShellArg domain} ${lib.escapeShellArg domain} \
${lib.escapeShellArg domain} ${lib.escapeShellArg domain}
printf 'basicConstraints=critical,CA:FALSE\n'
printf 'keyUsage=critical,digitalSignature,keyEncipherment\n'
printf 'extendedKeyUsage=serverAuth\n'
} > "$ext"
openssl x509 -req -in "$csr" -CA "$ca" -CAkey "$cak" \
-CAcreateserial -days ${toString cfg.leafValidityDays} -sha256 \
-extfile "$ext" -out "$leaf"
chmod 0600 "$leafk"
chmod 0644 "$leaf"
fi
'';
};
# Signal the hive-c0re lifecycle that a hive CA exists: it bind-mounts
# this file (read-only, the CA cert ONLY — never the key) into each
# agent container so agents + their tools can trust the gateway's
# self-signed leaf, and the meta flake wires the per-agent trust
# bundle. Only the `ca.pem` path is exposed; `ca-key.pem` stays on the
# host (an agent that could read it could mint trusted certs).
systemd.services.hive-c0re.environment.HIVE_TLS_CA_PATH = "${cfg.stateDir}/ca.pem";
};
}