anti/DECNET
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity
Files
bbb126e435ef00eb88ba64858d7d1a21ebda6d47
DECNET/tests/service_testing/test_dns.py
anti bbb126e435 feat(dns): fix three operational blind spots — flood detection, AAAA, recon burst 
- Add per-src QPS counter (_qps_window) with flood_suspect event at ≥50 qps/10s;
  one event per src per 30s cooldown, does not suppress baseline query events.
- Add tracking_evicted telemetry every 100 LRU evictions so IP-rotation evasion
  of _txt_times/_qps_window/_recon_window is observable, not silent.
- Shared _track_lru helper consolidates LRU touch + eviction signalling across
  all three bounded OrderedDicts.
- Add TYPE_AAAA=28 support: _fake_ipv6() returns deterministic ULA (fd::/8)
  addresses for in-zone names; extra_records parser now accepts and validates
  AAAA entries via socket.inet_pton.
- Add per-src recon-burst aggregation (_recon_window): fingerprint_probe +
  zone_transfer + amp_probe are tracked per source in a 60s window; recon_burst
  fires when ≥2 distinct signal types seen, once per src per 120s cooldown.
- 47 tests passing (19 new across TestAAAARecords, TestFloodDetection, TestReconBurst).
2026-05-21 19:50:09 -04:00

536 lines
22 KiB
Python
Raw Blame History

"""Tests for decnet/templates/dns/server.py and decnet/services/dns.py."""
import collections
import hashlib
import importlib.util
import socket
import struct
import sys
from types import ModuleType
from unittest.mock import MagicMock, patch
import pytest
_SERVER_PATH = "decnet/templates/dns/server.py"
# ── Test helpers ──────────────────────────────────────────────────────────────
def _make_fake_syslog_bridge() -> ModuleType:
mod = ModuleType("syslog_bridge")
events: list[tuple[str, dict]] = []
def syslog_line(service, hostname, event_type, severity=6, **fields):
events.append((event_type, fields))
return f"LOG {event_type}"
mod.syslog_line = syslog_line
mod.write_syslog_file = MagicMock()
mod.forward_syslog = MagicMock()
mod.SEVERITY_INFO = 6
mod.SEVERITY_WARNING = 4
mod.encode_secret = MagicMock(return_value={"secret_printable": "", "secret_b64": ""})
mod._events = events
return mod
def _make_fake_instance_seed() -> ModuleType:
import random as _random
mod = ModuleType("instance_seed")
mod.rng = _random.Random(42)
mod.pick = lambda choices: list(choices)[0]
mod.instance_uuid = lambda ns="": f"aaaabbbb-cccc-dddd-eeee-{ns[:12].ljust(12, '0')}"
mod.instance_hex = lambda nbytes, ns="": (hashlib.sha256(ns.encode()).hexdigest() * 4)[:nbytes * 2]
mod.hostname = lambda: "testhost"
mod.jitter = MagicMock()
return mod
def _load_dns(extra_env: dict | None = None):
"""Load server.py in isolation with mocked syslog_bridge and instance_seed."""
env = {
"NODE_NAME": "testhost",
"DNS_ZONE_MODE": "auth",
"DNS_DOMAIN": "test.local",
"DNS_BIND_VERSION": "9.11.4-TEST",
"DNS_NSID": "testnsid",
"DNS_EXTRA_RECORDS": "",
**(extra_env or {}),
}
for key in list(sys.modules):
if key in ("dns_server", "syslog_bridge", "instance_seed"):
del sys.modules[key]
bridge = _make_fake_syslog_bridge()
seed = _make_fake_instance_seed()
sys.modules["syslog_bridge"] = bridge
sys.modules["instance_seed"] = seed
spec = importlib.util.spec_from_file_location("dns_server", _SERVER_PATH)
mod = importlib.util.module_from_spec(spec) # type: ignore[arg-type]
with patch.dict("os.environ", env, clear=False):
spec.loader.exec_module(mod) # type: ignore[union-attr]
# Reset per-src state between tests
mod._txt_times.clear()
mod._qps_window.clear()
mod._flood_cooldown.clear()
mod._recon_window.clear()
mod._recon_cooldown.clear()
return mod, bridge._events
def _build_query(
qname: str,
qtype: int,
qclass: int = 1,
qid: int = 0x1234,
rd: bool = True,
) -> bytes:
"""Minimal DNS query wire packet."""
flags = 0x0100 if rd else 0x0000
header = struct.pack(">HHHHHH", qid, flags, 1, 0, 0, 0)
wire = b""
for label in qname.rstrip(".").split("."):
enc = label.encode("ascii")
wire += bytes([len(enc)]) + enc
wire += b"\x00"
return header + wire + struct.pack(">HH", qtype, qclass)
def _rcode(data: bytes) -> int:
return struct.unpack_from(">H", data, 2)[0] & 0x0F
def _counts(data: bytes) -> tuple[int, int, int, int]:
_, _, qd, an, ns, ar = struct.unpack_from(">HHHHHH", data, 0)
return qd, an, ns, ar
def _events_of(events: list, kind: str) -> list[dict]:
return [fields for etype, fields in events if etype == kind]
# ── Auth zone ─────────────────────────────────────────────────────────────────
class TestAuthZone:
def test_a_record_apex(self):
mod, events = _load_dns()
resp = mod._handle(_build_query("test.local", mod.TYPE_A), "1.2.3.4", 1234, "udp")
assert resp is not None
assert _rcode(resp) == mod.RCODE_NOERROR
_, ancount, _, _ = _counts(resp)
assert ancount >= 1
assert _events_of(events, "query")
def test_a_record_www(self):
mod, events = _load_dns()
resp = mod._handle(_build_query("www.test.local", mod.TYPE_A), "1.2.3.4", 1234, "udp")
assert resp is not None
assert _rcode(resp) == mod.RCODE_NOERROR
_, ancount, _, _ = _counts(resp)
assert ancount >= 1
def test_nxdomain_unknown_name(self):
mod, _ = _load_dns()
resp = mod._handle(_build_query("nobody.test.local", mod.TYPE_A), "1.2.3.4", 1234, "udp")
assert resp is not None
assert _rcode(resp) == mod.RCODE_NXDOMAIN
def test_out_of_zone_refused_in_auth_mode(self):
mod, _ = _load_dns({"DNS_ZONE_MODE": "auth"})
resp = mod._handle(_build_query("google.com", mod.TYPE_A), "1.2.3.4", 1234, "udp")
assert resp is not None
assert _rcode(resp) == mod.RCODE_REFUSED
def test_soa_record(self):
mod, events = _load_dns()
resp = mod._handle(_build_query("test.local", mod.TYPE_SOA), "1.2.3.4", 1234, "udp")
assert resp is not None
assert _rcode(resp) == mod.RCODE_NOERROR
_, ancount, _, _ = _counts(resp)
assert ancount >= 1
def test_mx_record(self):
mod, events = _load_dns()
resp = mod._handle(_build_query("test.local", mod.TYPE_MX), "1.2.3.4", 1234, "udp")
assert resp is not None
assert _rcode(resp) == mod.RCODE_NOERROR
def test_extra_records_parsed(self):
mod, events = _load_dns({"DNS_EXTRA_RECORDS": "extra A 192.168.0.50"})
resp = mod._handle(_build_query("extra.test.local", mod.TYPE_A), "1.2.3.4", 1234, "udp")
assert resp is not None
assert _rcode(resp) == mod.RCODE_NOERROR
# ── AAAA / IPv6 ───────────────────────────────────────────────────────────────
class TestAAAARecords:
def test_aaaa_apex(self):
mod, _ = _load_dns()
resp = mod._handle(_build_query("test.local", mod.TYPE_AAAA), "1.2.3.4", 1234, "udp")
assert resp is not None
assert _rcode(resp) == mod.RCODE_NOERROR
_, ancount, _, _ = _counts(resp)
assert ancount >= 1
def test_aaaa_rdata_is_16_bytes_and_ula(self):
mod, _ = _load_dns()
resp = mod._handle(_build_query("test.local", mod.TYPE_AAAA), "1.2.3.4", 1234, "udp")
assert resp is not None
# Walk past header(12) + question to reach answer RDATA
# Question: encoded "test.local" + 4 bytes type/class
# We just need to find a 16-byte block starting with 0xfd somewhere
# The AAAA RDATA is 16 bytes; first byte must be 0xfd (ULA)
assert b"\xfd" in resp # ULA fd::/8
def test_aaaa_www(self):
mod, _ = _load_dns()
resp = mod._handle(_build_query("www.test.local", mod.TYPE_AAAA), "1.2.3.4", 1234, "udp")
assert resp is not None
assert _rcode(resp) == mod.RCODE_NOERROR
_, ancount, _, _ = _counts(resp)
assert ancount >= 1
def test_aaaa_out_of_zone_refused(self):
mod, _ = _load_dns({"DNS_ZONE_MODE": "auth"})
resp = mod._handle(_build_query("google.com", mod.TYPE_AAAA), "1.2.3.4", 1234, "udp")
assert resp is not None
assert _rcode(resp) == mod.RCODE_REFUSED
def test_extra_record_aaaa(self):
mod, _ = _load_dns({"DNS_EXTRA_RECORDS": "ipv6host AAAA fd00::1234"})
resp = mod._handle(_build_query("ipv6host.test.local", mod.TYPE_AAAA), "1.2.3.4", 1234, "udp")
assert resp is not None
assert _rcode(resp) == mod.RCODE_NOERROR
_, ancount, _, _ = _counts(resp)
assert ancount >= 1
def test_extra_record_invalid_aaaa_skipped(self):
"""Invalid AAAA value in DNS_EXTRA_RECORDS must not crash the server."""
mod, _ = _load_dns({"DNS_EXTRA_RECORDS": "badhost AAAA not-an-ipv6"})
# If we got a module, the parser didn't crash
resp = mod._handle(_build_query("badhost.test.local", mod.TYPE_AAAA), "1.2.3.4", 1234, "udp")
assert resp is not None
assert _rcode(resp) == mod.RCODE_NXDOMAIN # record was silently dropped
def test_fake_ipv6_returns_ula(self):
mod, _ = _load_dns()
ip6 = mod._fake_ipv6("test")
parsed = socket.inet_pton(socket.AF_INET6, ip6)
assert parsed[0] == 0xFD # first byte must be fd
def test_fake_ipv6_deterministic(self):
mod, _ = _load_dns()
assert mod._fake_ipv6("x") == mod._fake_ipv6("x")
def test_fake_ipv6_distinct_labels(self):
mod, _ = _load_dns()
assert mod._fake_ipv6("zone") != mod._fake_ipv6("ns2")
# ── Fingerprint probes ────────────────────────────────────────────────────────
class TestFingerprintProbe:
def test_version_bind_returns_configured_banner(self):
mod, events = _load_dns()
query = _build_query("version.bind", mod.TYPE_TXT, qclass=mod.CLASS_CH)
resp = mod._handle(query, "10.0.0.1", 12345, "udp")
assert resp is not None
assert _rcode(resp) == mod.RCODE_NOERROR
_, ancount, _, _ = _counts(resp)
assert ancount == 1
probes = _events_of(events, "fingerprint_probe")
assert probes
assert probes[0]["probe"] == "version.bind"
assert probes[0]["response"] == "9.11.4-TEST"
def test_hostname_bind_emits_fingerprint_probe(self):
mod, events = _load_dns()
query = _build_query("hostname.bind", mod.TYPE_TXT, qclass=mod.CLASS_CH)
resp = mod._handle(query, "10.0.0.1", 12345, "udp")
assert resp is not None
assert _events_of(events, "fingerprint_probe")
def test_id_server_emits_fingerprint_probe(self):
mod, events = _load_dns()
query = _build_query("id.server", mod.TYPE_TXT, qclass=mod.CLASS_CH)
resp = mod._handle(query, "10.0.0.1", 12345, "udp")
assert resp is not None
assert _events_of(events, "fingerprint_probe")
def test_unknown_chaos_is_refused_still_logged(self):
mod, events = _load_dns()
query = _build_query("something.chaos", mod.TYPE_TXT, qclass=mod.CLASS_CH)
resp = mod._handle(query, "10.0.0.1", 12345, "udp")
assert resp is not None
assert _rcode(resp) == mod.RCODE_REFUSED
assert _events_of(events, "fingerprint_probe")
def test_no_query_event_for_fingerprint(self):
mod, events = _load_dns()
query = _build_query("version.bind", mod.TYPE_TXT, qclass=mod.CLASS_CH)
mod._handle(query, "10.0.0.1", 12345, "udp")
assert not _events_of(events, "query")
# ── Zone transfer ─────────────────────────────────────────────────────────────
class TestZoneTransfer:
def test_axfr_refused_and_logged(self):
mod, events = _load_dns()
query = _build_query("test.local", mod.TYPE_AXFR)
resp = mod._handle(query, "5.5.5.5", 9999, "tcp")
assert resp is not None
assert _rcode(resp) == mod.RCODE_REFUSED
xfers = _events_of(events, "zone_transfer")
assert xfers
assert xfers[0]["qtype"] == "AXFR"
assert xfers[0]["transport"] == "tcp"
def test_ixfr_refused_and_logged(self):
mod, events = _load_dns()
query = _build_query("test.local", mod.TYPE_IXFR)
resp = mod._handle(query, "5.5.5.5", 9999, "tcp")
assert resp is not None
assert _rcode(resp) == mod.RCODE_REFUSED
xfers = _events_of(events, "zone_transfer")
assert xfers
assert xfers[0]["qtype"] == "IXFR"
# ── Amp probes ────────────────────────────────────────────────────────────────
class TestAmpProbe:
def test_qtype_any_emits_amp_probe(self):
mod, events = _load_dns()
query = _build_query("test.local", mod.TYPE_ANY)
resp = mod._handle(query, "2.2.2.2", 5353, "udp")
assert resp is not None
assert _events_of(events, "amp_probe")
def test_amp_probe_suppresses_plain_query_event(self):
mod, events = _load_dns()
query = _build_query("test.local", mod.TYPE_ANY)
mod._handle(query, "2.2.2.2", 5353, "udp")
assert not _events_of(events, "query")
# ── Tunneling heuristic ───────────────────────────────────────────────────────
class TestTunnelingHeuristic:
def test_long_high_entropy_label(self):
mod, events = _load_dns()
# 40-char high-entropy label (mix of alpha + digits)
label = "abcdefghijklmnopqrstuvwxyz0123456789abcd"
assert len(label) >= mod._LABEL_LEN_THRESHOLD
query = _build_query(f"{label}.test.local", mod.TYPE_A)
resp = mod._handle(query, "9.9.9.9", 1234, "udp")
assert resp is not None
assert _events_of(events, "tunneling_suspect")
def test_rapid_txt_burst_triggers_tunneling(self):
mod, events = _load_dns()
src = "3.3.3.3"
# 5 TXT queries in rapid succession triggers the burst heuristic
for i in range(5):
query = _build_query(f"chunk{i}.test.local", mod.TYPE_TXT)
mod._handle(query, src, 1234, "udp")
assert _events_of(events, "tunneling_suspect")
def test_tunneling_suppresses_plain_query_event(self):
mod, events = _load_dns()
label = "abcdefghijklmnopqrstuvwxyz0123456789abcd"
query = _build_query(f"{label}.test.local", mod.TYPE_A)
mod._handle(query, "9.9.9.9", 1234, "udp")
assert not _events_of(events, "query")
# ── Flood detection ───────────────────────────────────────────────────────────
class TestFloodDetection:
def test_flood_threshold_emits_flood_suspect(self):
mod, events = _load_dns()
src = "7.7.7.7"
# Send _FLOOD_THRESHOLD queries (default 50) in one shot
for i in range(mod._FLOOD_THRESHOLD):
mod._handle(_build_query(f"q{i}.test.local", mod.TYPE_A), src, 1234, "udp")
assert _events_of(events, "flood_suspect")
def test_flood_suspect_fires_only_once_within_cooldown(self):
mod, events = _load_dns()
src = "8.8.8.8"
# Send well above threshold — should still be one event due to cooldown
for i in range(mod._FLOOD_THRESHOLD * 2):
mod._handle(_build_query(f"q{i}.test.local", mod.TYPE_A), src, 1234, "udp")
floods = _events_of(events, "flood_suspect")
assert len(floods) == 1
def test_flood_does_not_suppress_query_events(self):
"""flood_suspect is additive — baseline query events still fire."""
mod, events = _load_dns()
src = "9.9.9.8"
for i in range(mod._FLOOD_THRESHOLD):
mod._handle(_build_query(f"r{i}.test.local", mod.TYPE_A), src, 1234, "udp")
# Queries from a flooding src still produce query events
assert _events_of(events, "query")
def test_flood_includes_qps_and_window(self):
mod, events = _load_dns()
src = "6.6.6.6"
for i in range(mod._FLOOD_THRESHOLD):
mod._handle(_build_query(f"q{i}.test.local", mod.TYPE_A), src, 1234, "udp")
floods = _events_of(events, "flood_suspect")
assert floods
assert "qps" in floods[0]
assert "window_sec" in floods[0]
def test_tracking_evicted_on_lru_overflow(self):
mod, events = _load_dns()
# Fill qps_window beyond _MAX_TRACKED_SRCS to trigger eviction
# We need _EVICT_EVENT_EVERY evictions to fire tracking_evicted
evict_target = mod._EVICT_EVENT_EVERY
capacity = mod._MAX_TRACKED_SRCS
for i in range(capacity + evict_target):
src = f"10.{i >> 16 & 0xFF}.{i >> 8 & 0xFF}.{i & 0xFF}"
mod._handle(_build_query("test.local", mod.TYPE_A), src, 1234, "udp")
assert _events_of(events, "tracking_evicted")
# ── Recon burst aggregation ───────────────────────────────────────────────────
class TestReconBurst:
def test_fingerprint_then_axfr_triggers_recon_burst(self):
mod, events = _load_dns()
src = "5.5.5.1"
# fingerprint_probe
mod._handle(
_build_query("version.bind", mod.TYPE_TXT, qclass=mod.CLASS_CH),
src, 1234, "udp",
)
# zone_transfer
mod._handle(_build_query("test.local", mod.TYPE_AXFR), src, 1234, "tcp")
bursts = _events_of(events, "recon_burst")
assert bursts
assert bursts[0]["distinct_types"] == 2
def test_recon_burst_fires_only_once_within_cooldown(self):
mod, events = _load_dns()
src = "5.5.5.2"
for _ in range(3):
mod._handle(
_build_query("version.bind", mod.TYPE_TXT, qclass=mod.CLASS_CH),
src, 1234, "udp",
)
mod._handle(_build_query("test.local", mod.TYPE_AXFR), src, 1234, "tcp")
bursts = _events_of(events, "recon_burst")
assert len(bursts) == 1
def test_recon_burst_different_srcs_no_cross_trigger(self):
mod, events = _load_dns()
# src A does fingerprint, src B does zone_transfer — no burst for either
mod._handle(
_build_query("version.bind", mod.TYPE_TXT, qclass=mod.CLASS_CH),
"5.5.5.3", 1234, "udp",
)
mod._handle(_build_query("test.local", mod.TYPE_AXFR), "5.5.5.4", 1234, "tcp")
assert not _events_of(events, "recon_burst")
def test_recon_burst_does_not_suppress_source_events(self):
mod, events = _load_dns()
src = "5.5.5.5"
mod._handle(
_build_query("version.bind", mod.TYPE_TXT, qclass=mod.CLASS_CH),
src, 1234, "udp",
)
mod._handle(_build_query("test.local", mod.TYPE_AXFR), src, 1234, "tcp")
# Source events must still fire
assert _events_of(events, "fingerprint_probe")
assert _events_of(events, "zone_transfer")
# And the burst on top
assert _events_of(events, "recon_burst")
def test_amp_plus_fingerprint_triggers_recon_burst(self):
mod, events = _load_dns()
src = "5.5.5.6"
mod._handle(
_build_query("version.bind", mod.TYPE_TXT, qclass=mod.CLASS_CH),
src, 1234, "udp",
)
mod._handle(_build_query("test.local", mod.TYPE_ANY), src, 1234, "udp")
bursts = _events_of(events, "recon_burst")
assert bursts
assert bursts[0]["distinct_types"] == 2
# ── Zone mode: open ───────────────────────────────────────────────────────────
class TestZoneModeOpen:
def test_open_mode_resolves_any_name(self):
mod, _ = _load_dns({"DNS_ZONE_MODE": "open"})
for qname in ("evil.example.com", "c2.attacker.net", "random.io"):
query = _build_query(qname, mod.TYPE_A)
resp = mod._handle(query, "4.4.4.4", 1234, "udp")
assert resp is not None, f"no response for {qname}"
assert _rcode(resp) == mod.RCODE_NOERROR
_, ancount, _, _ = _counts(resp)
assert ancount >= 1
def test_open_mode_returns_loopback_sinkhole(self):
mod, _ = _load_dns({"DNS_ZONE_MODE": "open"})
# The sinkhole A record must be in 127.0.0.0/8
query = _build_query("anything.com", mod.TYPE_A)
resp = mod._handle(query, "4.4.4.4", 1234, "udp")
assert resp is not None
# Find the A RDATA — walk past header(12) + question + answer name
# Just verify the response contains 127 somewhere in a 4-byte window
assert b"\x7f" in resp # 0x7f = 127
# ── Zone mode: recursive ──────────────────────────────────────────────────────
class TestZoneModeRecursive:
def test_recursive_mode_sets_ra_flag(self):
mod, _ = _load_dns({"DNS_ZONE_MODE": "recursive"})
query = _build_query("out-of-zone.example.com", mod.TYPE_A)
resp = mod._handle(query, "1.1.1.1", 1234, "udp")
assert resp is not None
flags = struct.unpack_from(">H", resp, 2)[0]
ra = bool(flags & 0x0080)
assert ra
# ── Service registration ──────────────────────────────────────────────────────
class TestServiceRegistration:
def test_dns_registered_by_name(self):
from decnet.services.registry import get_service
svc = get_service("dns")
assert svc is not None
assert svc.name == "dns"
def test_dns_port_53(self):
from decnet.services.registry import get_service
svc = get_service("dns")
assert 53 in svc.ports
def test_dns_udp_ports(self):
from decnet.services.registry import get_service
svc = get_service("dns")
assert 53 in svc.udp_ports()
def test_compose_fragment_structure(self):
from decnet.services.registry import get_service
svc = get_service("dns")
frag = svc.compose_fragment("decky-01", log_target="127.0.0.1:514")
assert "build" in frag
assert frag["container_name"] == "decky-01-dns"
assert frag["environment"]["NODE_NAME"] == "decky-01"
assert frag["environment"]["LOG_TARGET"] == "127.0.0.1:514"
assert "DNS_ZONE_MODE" in frag["environment"]
assert "DNS_BIND_VERSION" in frag["environment"]
def test_compose_fragment_no_log_target(self):
from decnet.services.registry import get_service
svc = get_service("dns")
frag = svc.compose_fragment("decky-02")
assert "LOG_TARGET" not in frag["environment"]
def test_dockerfile_context_points_to_template(self):
from decnet.services.registry import get_service
svc = get_service("dns")
ctx = svc.dockerfile_context()
assert ctx is not None
assert ctx.name == "dns"
assert (ctx / "Dockerfile").exists()
Reference in New Issue View Git Blame Copy Permalink