hyperhive/nix/host-modules/hive-c0re/default.nix
atlas 30a2a2e9de feat(#2641): sudoless hivectl via a hive-admin group on the host socket
The host admin socket `/run/hyperhive/host.sock` was `0660 root:root` (no
SocketGroup), so hivectl needed sudo. Group-own it by a new `hive-admin`
group and add a `services.hyperhive.c0re.adminUsers` allowlist: listed users
join `hive-admin` and drive hivectl without root.

- `SocketGroup = "hive-admin"`, `SocketMode = "0660"` on the hive-c0re.socket
  unit.
- `/run/hyperhive` -> `0751` (traverse-only, no listing) so the group can reach
  the socket path; the socket's own `0660 hive-admin` mode gates the
  connection, and the per-agent subdirs keep their own restrictive perms.
- Empty `adminUsers` (the default) leaves `hive-admin` memberless -> root-only,
  as before.

The admin socket is full hive control (spawn/kill/destroy/deploy), so
`adminUsers` is an explicit, opt-in trust grant. Documented in
docs/boundary.md (host admin socket access) + docs/tools/hivectl.md.
2026-07-22 22:50:27 +02:00

283 lines
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Nix

# The hive-c0re coordinator daemon (runs as the unprivileged
# `hive-core` user), socket-activated at /run/hyperhive/host.sock.
# Layout: ./options.nix (option declarations), ./theme.nix (stylix
# frontend theming → `servedFrontend`), ./environment.nix (the daemon
# unit's env attrset). The root privileged helper it delegates to is
# its own module (../hive-priv.nix).
{
pkgs,
lib,
config,
...
}:
let
cfg = config.services.hyperhive.c0re;
# Privsep splits ownership across users, so git/libgit2's dubious-
# ownership guard trips on legitimate cross-user reads: hive-priv (root)
# fetches the hive-core-owned meta/applied repos via nix, and hive-c0re
# (hive-core) fetches the agent-owned proposed-config repos. Both
# processes are trusted and can already read the files; this gitconfig
# only satisfies the ownership guard. libgit2 honours the literal `*`
# (mid-path globs aren't supported, so per-agent repos can't be listed);
# in practice these processes only ever touch hyperhive's own repos.
#
# The agent config inputs now live on the forge
# (`git+http://${forge.domain}/agent-configs/<n>.git`, see meta.rs render),
# so hive-core's `nix flake update` of those inputs is an authenticated
# `git+http` fetch. The `[credential]` stanza points git at the `hive-forge`
# helper below (scoped to the forge host) so the fetch authenticates as the
# forge `core` user with no token in any URL or lock.
safeDirGitconfig = pkgs.writeText "hyperhive-safe-gitconfig" ''
[safe]
directory = *
[credential "http://${config.services.hyperhive.forge.domain}"]
helper = hive-forge
username = core
[http]
# Abort a stalled fetch instead of blocking startup indefinitely. If a
# git+http transfer (e.g. `nix flake lock` of the forge-hosted config
# inputs) drops below 1 KiB/s for 30s -- forge unreachable / not ready
# on cold boot -- git fails fast rather than hanging the whole daemon.
# Pairs with GIT_TERMINAL_PROMPT=0 (no credential-prompt hang) and the
# migration shellout timeout in migrate.rs.
lowSpeedLimit = 1024
lowSpeedTime = 30
'';
# git credential helper for hive-core's authenticated fetches of the
# agent-config repos on the forge. Reads the live forge-core admin token
# (`/var/lib/hyperhive/forge-core-token` — paths.rs `FORGE_CORE_TOKEN`) on
# every invocation, so it never holds a stale copy and survives token
# rotation. Scoped to the forge host by the `[credential]` stanza above;
# implements the git credential-helper protocol (only `get` answers).
forgeCredHelper = pkgs.writeShellScriptBin "git-credential-hive-forge" ''
[ "''${1:-}" = "get" ] || exit 0
if [ -r /var/lib/hyperhive/forge-core-token ]; then
printf 'username=core\n'
printf 'password=%s\n' "$(cat /var/lib/hyperhive/forge-core-token)"
fi
'';
# The `hive-c0re serve` config JSON. Keys are snake_case to match the
# `ServeConfig` serde shape the daemon deserialises (the
# container-injected HiveEnv fields, flattened, plus the hive-c0re-local
# model_prices table); per-flag overrides still work for ad-hoc
# invocations.
#
# Written to `/etc/hyperhive/serve.json` (managed by
# `environment.etc`) rather than embedded as a store-path argument in
# ExecStart. This keeps ExecStart byte-stable across deploys that only
# change hyperhive module files (gateway, frontend, unrelated nix
# modules) so systemd does NOT restart hive-c0re — and therefore does
# NOT trigger a startup sweep that rebuilds every agent — unless the
# c0re binary itself changes.
serveConfigJson = builtins.toJSON {
hyperhive_flake = cfg.hyperhiveFlake;
hyperhive_docs_flake = cfg.hyperhiveDocs;
nixpkgs_flake = cfg.nixpkgsFlake;
dashboard_port = cfg.dashboardPort;
operator_pronouns = cfg.operatorPronouns;
context_window_tokens = cfg.contextWindowTokens;
agent_cpu_quota = cfg.agentCpuQuota;
agent_memory_max = cfg.agentMemoryMax;
model_prices = cfg.modelPrices;
build_slots = cfg.buildSlots;
};
in
{
imports = [
./options.nix
./theme.nix
];
config = lib.mkIf cfg.enable {
environment.systemPackages = [
cfg.package
pkgs.git
# XDG icons + .desktop entries so desktop environments can match
# hyperhive processes to their icon (task managers, CPU monitors, etc.).
cfg.xdgIcons
];
# Serve config at a stable /etc path so hive-c0re's ExecStart
# doesn't embed a volatile store-path argument. See serveConfigJson
# above for the rationale.
environment.etc."hyperhive/serve.json".text = serveConfigJson;
# Pull the per-container toplevels into the host system closure.
# `system.extraDependencies` adds paths to the system build
# without referencing them at runtime — nixos-rebuild fetches /
# builds them, they end up in /nix/store, and the first
# nixos-container update + start for an agent has nothing left to
# do. Gated because the closure is sizeable and pinned to x86_64.
system.extraDependencies = lib.optionals cfg.preBuildAgentTemplates [
cfg.agentBaseToplevel
cfg.managerToplevel
];
# Unprivileged coordinator user. hive-c0re runs as this user;
# privileged operations are delegated to hive-priv which runs as
# root, socket-activated at /run/hive/priv.sock (./hive-priv.nix).
users.users.hive-core = {
isSystemUser = true;
group = "hive-core";
description = "hive-c0re coordinator daemon user";
};
users.groups.hive-core = { };
# Operators granted sudoless `hivectl`. Members of `hive-admin` can
# connect to the host admin socket (group-owned by hive-admin via the
# socket unit's `SocketGroup` below) without root. That socket is *full*
# hive control (spawn/kill/destroy/deploy, docs/boundary.md), so this is
# an explicit opt-in allowlist — empty by default (root-only).
users.groups.hive-admin = {
members = cfg.adminUsers;
};
# The gateway nginx is always the sole external entry point (it runs
# alongside hyperhive), so the per-agent web-port range stays closed on
# the host firewall. See `docs/gateway.md::Firewall posture (host-level)`.
# NB: `services.hyperhive.domain` is required when hyperhive is
# enabled — the canonical assertion lives in `hive-network.nix` (the
# hive resolver is authoritative for `<domain>` and agents reach the
# forge/matrix through the gateway by it). So the daemon environment
# (./environment.nix) can treat it as non-null.
systemd.services.hive-c0re = {
description = "hyperhive coordinator daemon";
wantedBy = [ "multi-user.target" ];
# Socket unit must start before the service so hive-c0re receives the
# pre-bound fd via LISTEN_FDS (socket activation). Without this
# dependency, nixos-rebuild switch activates hive-c0re.socket while
# hive-c0re.service is already running (started by multi-user.target),
# and systemd refuses with "Socket service already active". Adding
# requires+after causes systemd to stop the service, start the socket,
# then restart the service -- clean transition on every config apply.
requires = [ "hive-c0re.socket" ];
after = [ "hive-c0re.socket" ];
path = [
pkgs.git
# `git-credential-hive-forge` on PATH so git finds it when nix fetches
# the forge-hosted agent-config inputs (helper = hive-forge).
forgeCredHelper
"/run/current-system/sw"
];
environment = import ./environment.nix { inherit lib config pkgs; };
serviceConfig = {
ExecStart = "${cfg.package}/bin/hive-c0re --socket /run/hyperhive/host.sock serve --config /etc/hyperhive/serve.json";
SyslogIdentifier = "hive-c0re";
# Migrate hive-c0re's *own* state to the service user after an
# upgrade from a root-run install (systemd's StateDirectory only
# chowns the top-level dir, not pre-existing files inside it). The
# `+` prefix runs as root despite User = hive-core; `-` tolerates
# failure. coreutils ships `chown` but no `sh`, so invoke the
# binaries directly rather than through a shell.
#
# CRITICAL: exclude the per-agent `agents/` subtree. Its contents
# (each agent's `claude/` OAuth creds, `state/`, `harness/`,
# `config/`) are owned by the per-agent / manager users, and each
# container's `hive-agent-user-migrate` activation script chowns
# them back to that user on boot. Blanket-chowning them to hive-core
# makes every agent's `~/.claude` unreadable — logging them all out
# with no way to log back in. So chown everything *except* agents/,
# plus the `agents/` dir node itself (not its contents) so c0re can
# still create new per-agent subdirs.
ExecStartPre = [
# Install the safe.directory gitconfig at $HOME/.gitconfig
# (HOME = /var/lib/hyperhive) so c0re's `git fetch`/`rev-parse`
# against the agent-owned proposed repos pass the ownership guard.
# Placed before the chown below so it's chowned to hive-core too.
"+-${pkgs.coreutils}/bin/cp ${safeDirGitconfig} /var/lib/hyperhive/.gitconfig"
"+-${pkgs.findutils}/bin/find /var/lib/hyperhive -mindepth 1 -maxdepth 1 -not -name agents -exec ${pkgs.coreutils}/bin/chown -R hive-core:hive-core {} +"
"+-${pkgs.coreutils}/bin/chown hive-core:hive-core /var/lib/hyperhive/agents"
];
Restart = "on-failure";
RestartSec = 2;
User = "hive-core";
Group = "hive-core";
SupplementaryGroups = [ "systemd-journal" ];
RuntimeDirectory = "hyperhive";
# 0751 (traverse-only, no listing) so `hive-admin` operators can reach
# the host admin socket (`SocketGroup = "hive-admin"`, 0660) without
# root. Others can traverse but not list; the socket + per-agent
# subdirs gate access by their own perms. Matches the socket unit's
# DirectoryMode.
RuntimeDirectoryMode = "0751";
RuntimeDirectoryPreserve = "yes";
StateDirectory = "hyperhive";
StateDirectoryMode = "0750";
# OTEL auth-header secret, loaded onto hive-c0re's own unit so its
# per-agent container-resource metrics exporter can read it
# at $CREDENTIALS_DIRECTORY/otel-headers — via systemd, not a world
# path. Same secret the agent containers get (forwarded there via
# nspawn --load-credential); this just also hands it to c0re itself.
# Empty list (no credential) when otel is off or no header is set.
LoadCredential = lib.optional (
config.services.hyperhive.otel.enable && config.services.hyperhive.otel.headersCredential != null
) "otel-headers:${config.services.hyperhive.otel.headersCredential}";
# Sandboxing. hive-c0re is unprivileged (runs as hive-core, never
# setuid), makes HTTP requests to forge/matrix/Anthropic (keeps INET),
# and delegates all privileged ops to hive-priv via a Unix socket.
# These directives deny the subset of kernel capabilities it
# provably doesn't need without restricting its network or
# filesystem access (RestrictAddressFamilies deferred — needs a
# watched deploy to verify no AF_UNIX/AF_INET gaps in socket paths).
NoNewPrivileges = true; # already runs as unprivileged user
PrivateTmp = true; # uses StateDirectory for tmpfiles, not /tmp
ProtectHome = true; # HOME = /var/lib/hyperhive; no /home/* access needed
# "strict" makes the entire filesystem read-only except for
# StateDirectory (/var/lib/hyperhive) and RuntimeDirectory
# (/run/hyperhive), which systemd keeps writable. No
# ReadWritePaths needed beyond the managed directories because:
# - nix is invoked directly (lifecycle, meta, flake_check), but
# NIX_REMOTE=daemon routes all store writes through the host
# daemon — hive-c0re never writes to /nix itself.
# - flake.lock ops land in the meta worktree under StateDirectory
# (kept writable by systemd).
# - nix build worktrees live in PrivateTmp, not /tmp.
# - /etc writes (bind-mount edits) go through hive-priv via the
# privileged socket; /etc/hyperhive/serve.json is read-only.
ProtectSystem = "strict";
ProtectKernelTunables = true; # no sysctl writes
ProtectKernelLogs = true; # reads logs via systemd-journal group, not /dev/kmsg
ProtectControlGroups = true; # cgroup writes go through hive-priv, not c0re directly
RestrictNamespaces = true; # namespace creation goes through hive-priv
LockPersonality = true; # no personality changes needed
RestrictRealtime = true; # no real-time scheduling
};
};
# Socket unit for the hive-c0re admin socket. systemd creates and holds
# `/run/hyperhive/host.sock` before hive-c0re starts, then passes the fd
# via LISTEN_FDS (socket activation). Benefits: `hivectl` can connect
# the moment the socket unit is active — no racy retry window — and a
# hive-c0re restart never drops the socket inode, so queued commands
# drain cleanly.
#
# `hive-c0re serve` reads LISTEN_FDS via the `listenfd` crate and
# accepts the fd in preference to its own `bind()` path. When invoked
# directly (dev, CI, without the socket unit) LISTEN_FDS is absent and
# the traditional bind path runs unchanged — no regression.
systemd.sockets.hive-c0re = {
description = "hive-c0re admin socket";
wantedBy = [ "sockets.target" ];
socketConfig = {
# Must match the `--socket` arg passed to `hive-c0re serve`.
ListenStream = "/run/hyperhive/host.sock";
# `0660 root:hive-admin` — group-owned by `hive-admin` so operators in
# that group (services.hyperhive.c0re.adminUsers) drive `hivectl`
# without root; an empty adminUsers list leaves the group memberless,
# so it stays effectively root-only. See docs/boundary.md.
SocketMode = "0660";
SocketGroup = "hive-admin";
# `0751` (traverse-only, no listing) so hive-admin can reach the socket
# path — the socket's own `0660 hive-admin` gates the connection, and
# the per-agent subdirs under here keep their own restrictive perms.
# Must match the service unit's RuntimeDirectoryMode. DirectoryMode is
# only consulted when the dir is absent at socket-unit activation.
DirectoryMode = "0751";
};
};
};
}