Antivirus/packaging/build-deb.sh
Hound 432e2b825e packaging: four bugs that only a real install could find
Installed the .deb on the live server. The daemon did not start, and
everything below is what that one command surfaced.

1. MemoryDenyWriteExecute=yes stopped the service dead.

   yara-x compiles rules to WebAssembly and JITs them, so it needs pages
   that go writable then executable. With W^X enforced the daemon aborts
   at startup: "unable to make memory executable". The unit had passed
   systemd-analyze verify, which checks syntax and cannot know this.

   Now off, with the reasoning in the unit rather than in a commit
   nobody will read: a hardening directive that stops the service is
   worse than the exposure it prevents, because the machine ends up with
   no antivirus at all. What compensates is spelled out beside it.

2. Hound detected itself.

   The goodware gate reported /usr/bin/houndd as Linux.Coinminer.XMRig
   and Linux.Rootkit.Preload. Correctly: the built-in pack matches on
   "stratum+tcp://", "xmrig", "RTLD_NEXT" and "ld.so.preload", and the
   pack was embedded verbatim, so the daemon's own binary contained all
   of them.

   Not cosmetic. With the execution gate armed, Hound would have refused
   to execute itself or quarantined its own binary — a scanner that eats
   its own daemon the moment protection is switched on.

   The pack is now XOR-masked at build time (build.rs) and unmasked at
   startup. Not a secret — the rules are open source — the only job is
   keeping the literal bytes out of the executable. Two regression tests:
   the embedded blob carries no plaintext rule strings, and a built
   daemon binary in target/ carries none either.

3. The postinst copied the built-in pack into /var/lib/hound/rules,
   where the daemon compiled it a second time and logged a duplicate
   declaration on every start. That directory is for ADDITIONAL packs;
   the built-ins live in the binary. Removed from deb, rpm and AUR.

4. The daemon and the CLI disagreed about the socket. systemd gives the
   service /run/hound; the CLI looked in $XDG_RUNTIME_DIR and reported
   the daemon unreachable — technically true, entirely unhelpful.
   default_socket_path() now prefers /run/hound when it exists, the unit
   states HOUNDD_SOCK explicitly, and a permission error on the socket
   says "try: sudo hound" instead of "Permission denied".

Also: Recommends: clamav-daemon was wrong and apt duly installed clamd,
which took 970 MB of RSS on the live server. clamd is an optional
arm's-length engine, so it is a Suggests. I stopped and disabled the
copy my install pulled in.

Verified on the server after fixing: service active, status reports the
engine and the gate, EICAR caught, rootkit scan clean, and the goodware
gate passes across 3,955 system binaries including the now-installed
houndd.

The gate remains OFF. Turning it on for the host that serves Caddy is a
separate decision.

295 tests pass.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-08-21 07:43:03 -05:00

185 lines
6 KiB
Bash
Executable file

#!/usr/bin/env bash
#
# Build a .deb for Ubuntu / Debian / Linux Mint.
#
# Deliberately hand-rolled rather than cargo-deb: the package needs a
# postinst that creates the vault with the right mode, a conffile that
# survives upgrades, and a unit that is enabled but whose gate stays off
# until the operator turns it on. That is easier to read as a script than
# as a pile of metadata, and it is the thing most likely to need auditing.
set -euo pipefail
ROOT="$(cd "$(dirname "$0")/.." && pwd)"
VERSION="$(grep -m1 '^version' "$ROOT/Cargo.toml" | cut -d'"' -f2)"
ARCH="$(dpkg --print-architecture)"
OUT="${OUT:-$ROOT/dist}"
STAGE="$(mktemp -d)"
trap 'rm -rf "$STAGE"' EXIT
# mktemp -d creates 0700, and dpkg applies the staging root's mode to "/".
# Installing this package would chmod / to 0700 and break the machine.
chmod 0755 "$STAGE"
echo "building hound ${VERSION} (${ARCH})"
( cd "$ROOT" && cargo build --release -p houndd -p hound )
install -Dm755 "$ROOT/target/release/houndd" "$STAGE/usr/bin/houndd"
install -Dm755 "$ROOT/target/release/hound" "$STAGE/usr/bin/hound"
install -Dm644 "$ROOT/packaging/systemd/houndd.service" \
"$STAGE/lib/systemd/system/houndd.service"
install -Dm644 "$ROOT/crates/houndd/rules/hound-builtin.yar" \
"$STAGE/usr/share/hound/rules/hound-builtin.yar"
install -Dm644 "$ROOT/README.md" "$STAGE/usr/share/doc/hound/README.md"
# Launcher icon: the white mark on a periwinkle tile (app-*.png), not the
# bare brand mark. The tray ladder is a different family and ships with
# the GUI, because tray glyphs must stay transparent to sit on any panel.
for size in 16 22 24 32 48 64 128 256 512; do
src="$ROOT/assets/icons/app-${size}.png"
[ -f "$src" ] && install -Dm644 "$src" \
"$STAGE/usr/share/icons/hicolor/${size}x${size}/apps/hound.png"
done
install -Dm644 "$ROOT/assets/icons/hound-app.svg" \
"$STAGE/usr/share/icons/hicolor/scalable/apps/hound.svg"
install -Dm644 /dev/stdin "$STAGE/usr/share/applications/hound.desktop" <<'DESKTOP'
[Desktop Entry]
Type=Application
Name=Hound Antivirus
GenericName=Antivirus
Comment=Endpoint and supply-chain protection for Linux
Exec=hound
Icon=hound
Categories=System;Security;Utility;
Keywords=antivirus;malware;security;scan;supply chain;
Terminal=true
DESKTOP
mkdir -p "$STAGE/DEBIAN"
cat > "$STAGE/DEBIAN/control" <<CONTROL
Package: hound
Version: ${VERSION}
Section: utils
Priority: optional
Architecture: ${ARCH}
Maintainer: Hound <support@houndav.com>
Depends: libc6 (>= 2.34)
Suggests: clamav-daemon
Homepage: https://houndav.com
Description: Hound Antivirus for Linux
Endpoint and supply-chain protection built for the distributions people
actually run. Scanning is yara-x in process; real-time protection uses
fanotify, so a binary can be refused at execve rather than reported
after it has already run.
.
The execution gate is installed switched OFF. It needs CAP_SYS_ADMIN and
covers the whole root filesystem, so turning it on is the operator's
decision: hound settings set exec_gate true
CONTROL
cat > "$STAGE/DEBIAN/conffiles" <<'CONFFILES'
/etc/hound/hound.toml
CONFFILES
install -Dm644 /dev/stdin "$STAGE/etc/hound/hound.toml" <<'CONF'
# Hound Antivirus configuration.
#
# Live settings are managed through `hound settings` and stored per user;
# this file holds the machine-wide defaults the daemon starts from.
# Deny execution until a verdict is returned. Needs CAP_SYS_ADMIN.
# Off by default: it covers the whole root filesystem, and that is the
# operator's call to make rather than the installer's.
exec_gate = false
# Mounts the gate covers. Empty means the root filesystem.
exec_gate_paths = []
# Never held for a verdict.
exclude_paths = ["/proc", "/sys", "/dev", "/run", "/var/lib/docker"]
# Files larger than this are allowed through unread.
max_file_size_mb = 100
# "quarantine" or "alert".
on_detect = "quarantine"
CONF
cat > "$STAGE/DEBIAN/postinst" <<'POSTINST'
#!/bin/sh
set -e
case "$1" in
configure)
# The vault holds live malware: root-only, and on a filesystem where
# nothing in it can be executed even by accident.
mkdir -p /var/lib/hound/vault /var/lib/hound/rules /var/log/hound
chmod 0700 /var/lib/hound/vault
chmod 0755 /var/lib/hound /var/lib/hound/rules
chmod 0750 /var/log/hound
# The built-in rules are compiled INTO the binary; /var/lib/hound/rules
# is for additional packs only. Copying the built-ins there made the
# daemon compile them twice and log a duplicate-declaration error on
# every start. The copy under /usr/share is documentation, not input.
if [ -d /run/systemd/system ]; then
systemctl daemon-reload || true
systemctl enable houndd.service || true
systemctl restart houndd.service || true
fi
echo ""
echo "Hound is installed and scanning on demand."
echo ""
echo " hound status what the daemon sees"
echo " hound scan ~/Downloads scan a directory"
echo ""
echo "Real-time execution blocking is OFF until you turn it on:"
echo ""
echo " sudo hound settings set exec_gate true"
echo ""
;;
esac
exit 0
POSTINST
cat > "$STAGE/DEBIAN/prerm" <<'PRERM'
#!/bin/sh
set -e
case "$1" in
remove|deconfigure)
if [ -d /run/systemd/system ]; then
systemctl stop houndd.service || true
systemctl disable houndd.service || true
fi
;;
esac
exit 0
PRERM
cat > "$STAGE/DEBIAN/postrm" <<'POSTRM'
#!/bin/sh
set -e
case "$1" in
purge)
# The vault is deliberately NOT removed on `remove`, only on `purge`,
# and even then only after saying so: it may be the sole copy of
# evidence somebody still needs.
echo "Removing the Hound quarantine vault at /var/lib/hound/vault"
rm -rf /var/lib/hound /var/log/hound
;;
esac
if [ -d /run/systemd/system ]; then
systemctl daemon-reload || true
fi
exit 0
POSTRM
chmod 0755 "$STAGE/DEBIAN/postinst" "$STAGE/DEBIAN/prerm" "$STAGE/DEBIAN/postrm"
mkdir -p "$OUT"
DEB="$OUT/hound_${VERSION}_${ARCH}.deb"
fakeroot dpkg-deb --build --root-owner-group "$STAGE" "$DEB" >/dev/null
echo "built $DEB"
dpkg-deb -I "$DEB" | sed 's/^/ /'