Two mechanisms Joe asked for, neither of which existed.
**Definitions now update themselves.** `auto_update_signatures` shipped
from the start and nothing ever read it — definitions only moved when
somebody typed `hound update`, which for a security product means most
installations were running whatever they were installed with. There is
now a scheduler thread: definitions hourly, release check daily, and a
90-second startup delay so a fleet that reboots together does not
arrive at the CDN in one wave. It calls the same install path as
`hound update` rather than a second implementation that could drift.
**Release notifications, signed.** dl.houndav.com/latest.json carries
an Ed25519 signature from the same key as the definition packs, for the
same reason: whoever serves that host must not be able to invent a
version and point our users at a binary of their choosing. A manifest
that does not verify is discarded, and no manifest means "nothing newer
known" — never "update available". The safe default is silence.
The signature covers a canonical byte form defined identically in
release.rs and tools/publish-release.py. Signing a re-serialisation of
a parsed struct is the classic way to verify one thing and act on
another, so a test runs a real manifest produced by the Python tool
through the Rust verifier against the production key. If those drift,
manifests verify nowhere and the only symptom is that nobody ever hears
about an update.
Version comparison is numeric, not lexical, because "0.9.0" > "0.10.0"
as strings and that is precisely the pair where it would first be
noticed. Downgrades are never offered — a signed-but-old manifest must
not become a way to reintroduce a fixed vulnerability.
The app does not replace its own binary. A root daemon that can rewrite
itself is the mechanism a supply-chain attacker most wants. Installing
goes through apt with the user present and authenticating: the package
is downloaded, checked against the manifest's SHA-256, staged into a
root-owned 0700 directory so nothing can substitute it between the
check and the read, and handed over. Two guards beyond the signature —
the URL must be on our own download host, because a signature proves
publisher intent and not that the publisher got the URL right.
Tray, per Joe's design: a new amber "attention" state ranked below a
threat and an in-flight scan, above protected. Deeper amber than
"scanning" so the two are distinguishable — scanning lasts seconds and
the user started it, attention persists. The tooltip carries the reason
rather than only that there is one, and "Install Hound X…" appears
enabled only when there is something to install; a permanently greyed
item teaches people the menu is decorative.
Definition staleness is a first-class signal, not just update
availability: amber at 7 days, and at 30 the wording stops pretending —
"this machine is not currently protected against anything found since
then". An antivirus showing green on month-old definitions is lying in
the same way a dead front-end showing "Protected" was.
Also: the four files that declare a version now have a test asserting
they agree. Drift there means a release looks older than what is
installed and the update silently never offers, or offers forever.
377 tests pass.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
A clean laptop reported 988 critical rootkit findings; this server
3786, PID 1 among them. Every one was false, and the cause was our own
systemd hardening.
ProtectProc=invisible hides processes the daemon does not own from its
view of /proc, while kill(pid, 0) keeps answering truthfully because it
is a syscall and not a filesystem lookup. The hidden-process check
compares exactly those two sources, so with that setting every process
on the machine looked concealed. Enumerating processes is this daemon's
job, so it needs the default view.
Removing the setting is not enough on its own — hidepid= on the /proc
mount produces the same blindness and we do not control that. So the
detector now recognises when it cannot see:
- PID 1 is the control. It always exists and nothing hides init; a
rootkit that did would break the machine it is living on. If PID 1
answers kill(1, 0) but is absent from the listing, we are blind and
say so as info rather than crying rootkit.
- A plausibility ceiling of 32. Hiding a handful of processes is the
entire point of a rootkit; hundreds means a broken observer. An
antivirus that reports a critical rootkit finding on every clean
machine teaches people to ignore the one time it is real.
Also in this change, from testing on a real desktop:
- Closing the window hides it to the tray instead of exiting, with a
one-time notification so it does not read as a crash. Quit lives
only in the tray menu and confirms first. The settings already had
close_to_tray and confirm_quit fields wired to nothing; they are
honoured now rather than hardcoded.
- The tray menu and Scan Home sent the literal string "~". A shell
would have expanded it, nothing here did, so the daemon was asked
to scan a directory of that name. It failed silently until the
per-peer readability check made it audible.
- Administrative actions elevate through polkit instead of telling
people to open a terminal. The app tries unprivileged first and
only on a privilege refusal runs `pkexec hound admin-rpc`, which
forwards one request as root. auth_admin_keep, because prompting on
every settings toggle trains people to authenticate without reading
the prompt. This grants what `sudo hound` already grants to people
who could already run sudo — a transport, not a new privilege.
- `hound settings exec-gate on|off` now exists. The install script,
the AppImage banner, the rpm spec, the AUR install file and
llms.txt all told users to run `hound settings set exec_gate true`.
There was no `set` subcommand and no way to enable the execution
gate from the CLI at all: the flagship paid feature was unreachable
and the first thing a new user was told to type returned an error.
A test now asserts every documented command parses.
- `settings show` displays the exec gate state, and no longer prints
its own header twice.
- The CLI help still described ClamAV, which has not been the engine
for some time. So did the socket permission error, which now
explains the `hound` group and the log-out-and-back-in it needs.
368 tests pass.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
The start-menu entry ran `hound` with Terminal=true — the CLI, which
printed help and exited. No GUI binary had ever been built or packaged.
Four separate faults were stacked behind that report:
1. build-deb.sh now builds and ships hound-gui, and writes a .desktop
entry only when that binary exists. A launcher for software that is
not there is worse than no launcher.
2. Tray icons were loaded from a relative "icons/" path, which resolves
only from the build tree. Installed to /usr/bin the setup hook failed
and Tauri panicked before a window appeared. They are include_bytes!
now — four ~1 KB PNGs that can no longer be missing.
3. The front-end never ran at all. app.js opened with a bare module
specifier ("@tauri-apps/api/core") and there is no bundler, so the
webview could not resolve it and the script silently failed to parse.
The window rendered its static HTML forever, which looks exactly like
a daemon that never answered. withGlobalTauri + window.__TAURI__.
4. build-deb.sh ran the Tauri build as `>/dev/null 2>&1 || true`, so a
config error scrolled past unseen and the package shipped the
PREVIOUS binary. Two fixes appeared to do nothing. That step is no
longer silenced or tolerant of failure, and the build fails outright
on a bare import in gui/dist/*.js.
Guards, because each of these failed quietly: index.html flips to an
interface-error message if app.js never sets a boot flag within 5s. An
antivirus showing "Protected - your system looks healthy" while its own
front-end is dead is the worst failure mode there is.
Then the window came up and could not reach the daemon: the socket was
0700 root:root. Widening it needed more than a chmod, because
quarantine.restore writes files back out as root — handing that to a
desktop group would hand out root. So the daemon now checks SO_PEERCRED
per method (crates/houndd/src/peer.rs):
- group `hound`: status, settings.get, events, quarantine.list,
rootkit.scan, persistence.scan
- scan/supply.sweep: only paths the caller could read itself, decided
by forking a child, dropping to the peer's uid, gid and
supplementary groups, and asking access(2) — which honours ACLs and
mount options, unlike anything reconstructed from mode bits
- everything that writes: root, or the uid the daemon runs as
Unclassified methods fall into Admin, so a new mutating method fails
closed rather than becoming public by omission. The end-to-end socket
test caught that "root only" broke every developer run; the owner
clause collapses to "root" under the packaged root daemon and is
verified to do so.
CAP_SETUID/CAP_SETGID join the gate capability set for the readability
check. There was a test asserting CAP_SETUID must never be retained —
it is updated with the reasoning rather than deleted. The daemon
already holds CAP_DAC_OVERRIDE and CAP_DAC_READ_SEARCH, so becoming
another user widens nothing that matters. The unit gains Group=hound so
the socket can be chgrp'd without CAP_CHOWN; it stays uid 0.
Also: the footer claimed "engine: ClamAV via Unix socket". It reports
what the daemon actually loaded, which has been yara-x since the engine
was replaced. Every error path in the front-end goes through explain(),
so a privilege refusal reads as "run it from a terminal: sudo hound …"
rather than "daemon error -32000".
358 tests pass.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
ClamAV is a temporary dependency. Everything ClamAV-specific moves
behind a 4-method trait in crates/houndd/src/engine.rs:
trait ScanEngine { name; probe; scan; update }
struct ClamAvEngine // today
const ENGINE // one-line flip when the native engine lands
- parse_clamscan() is now a pure fn with unit tests (OK/FOUND/INCOMPLETE,
dedup, malformed lines)
- main.rs drops all clamscan/clamd/freshclam knowledge; Status reports
engine='clamav' via the trait
- README documents the seam and the wire contract that stays stable
GUI (gui/, Tauri 2, standalone workspace, vanilla JS premium-dark shell):
- system-tray sentinel on the 4-state dog-head ladder (green/amber/red/gray)
with tooltips; clicks open the window / scan / update
- window: protection hero, path + recursive scan, progress bar, results
table, signature update log; state mirrored to the tray
- compiles clean (cargo build, 0 warnings) on Mint 22.3 + webkit2gtk-4.1
All 11 workspace tests pass, incl. the E2E EICAR scan over the real
Unix-socket daemon (clamscan finds the planted EICAR).
dev
