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Merge feat/rate-limit: throttle /v1/link and /v1/repos

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Closes the last unbuilt item on the promotion-window hardening checklist.
Three codex rounds: 4 findings, then 3, then clean. 108 tests.

Co-Authored-By: Claude Opus 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01LTARYHX7GPepi3CH3tp5pg
This commit is contained in:
Nirav Patel
2026-08-22 23:31:41 -04:00
co-authored by Claude Opus 5
parent 137d2cdd53 c742ca4798
commit 1091aa61f2
4 changed files with 677 additions and 3 deletions
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README.md
+58 -2
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@@ -90,6 +90,59 @@ window. The service **refuses to start** (exit 2) unless `config.json` is
mode 0600/0400 and owned by the user it runs as — the config carries the
forge admin password, so permissive perms fail closed, not open.
#### Rate limiting
Sliding-window, per `(route, client)`, **on by default** — `/v1/link` creates
accounts and mints tokens, so unlimited has to be a deliberate config act,
never an omission. Defaults: `/v1/link` 5/hour, `/v1/repos` 60/hour. `GET
/health` is never limited. Over the limit → **429** with a `Retry-After`
header, decided *before* the body is read so an abusive caller costs nothing.
```json
"rate_limit": {
"enabled": true,
"trust_forwarded_for": false,
"trusted_proxies": [],
"rules": {"/v1/link": [5, 3600], "/v1/repos": [60, 3600]}
}
```
* Anything malformed **refuses startup** rather than silently meaning
unlimited: a bad rule, a non-boolean `enabled`/`trust_forwarded_for` (JSON
`null`, `0`, or the *string* `"false"` — every non-empty string is truthy),
or a `rate_limit` that is not an object. `[0, N]` disables an endpoint
outright.
* Denied requests are *not* recorded, so a client that keeps hammering cannot
push its own window forward and lock itself out permanently.
* State is an in-process dict behind a lock — granthi-link is one
`ThreadingHTTPServer`, so that is the entire store. **If this ever runs
multi-process or multi-host, the limiter must move with it.** The clock is
read *inside* the lock; taken outside, racing threads append out of order
and both `Retry-After` and window reclamation silently go wrong.
* The key store is capped (`MAX_RATE_KEYS`) **per route**, not globally. At
capacity it reclaims expired windows, and if every window is still live it
**refuses the new key** — fail closed. Evicting a live window would let an
attacker who can mint many distinct keys clear their *own* limit on demand.
The per-route budget matters just as much: with one shared table, a flood
of cheap `/v1/repos` keys would exhaust it and lock brand-new `/v1/link`
clients out, turning the fail-closed guard into a cross-route DoS.
* Rule values must be real integers. `bool` subclasses `int` in Python, so
`[5, true]` would otherwise pass as a **1-second** window — an hourly limit
quietly becoming ~5/sec.
* `trust_forwarded_for` is **off** by default, and turning it on **requires a
non-empty `trusted_proxies`** — the header is honored only when the socket
peer is in that list. Without it, anyone reaching the origin directly (it
also listens on the tailnet) could pick and rotate their own rate-limit key
just by sending a header. Turn it on when exposing behind cloudflared,
where every request otherwise arrives from the tunnel and one abuser would
starve everyone. A caller can *prepend* anything to `X-Forwarded-For`; a
trusted proxy *appends* the peer it actually saw, so the service reads the
**last** entry, never the first, and requires it to parse as a real IP.
`trusted_proxies` is validated at startup: it must be a list (a bare string
would be iterated character by character), every entry a valid network, and
wildcards (`0.0.0.0/0`, `::/0`) are refused outright — they would restore
exactly the "trust anyone" hole the setting exists to close.
#### Identity binding (`state.json`)
`/v1/link` originally bound purely by `preferred_username` / email
@@ -226,8 +279,11 @@ Every linked folder becomes a private repo under their account.
app is host-independent. Rotate the beta admin token/password out of the
config when pointing at prod (prod forge is READ-ONLY to this estate —
promotion is an operator action, not an agent action).
4. Add rate limiting / abuse controls before public exposure (one token mint
per link call today).
4. ~~Add rate limiting / abuse controls before public exposure.~~ **DONE** —
see "Rate limiting" above (5 links/hour per client by default). When
exposing behind cloudflared, set `trust_forwarded_for: true` in the same
change, or every request will look like the tunnel and one abuser will
throttle everybody.
5. **Hardening checklist (must all hold before exposing):**
- [ ] `config.json` is 0600 (or 0400) and owned by the service user —
the service refuses to start otherwise; verify with
server/config.example.json
+6 -1
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@@ -6,5 +6,10 @@
"admin_login": "nirpa",
"admin_password": "FROM /opt/gitea-beta/.admin-creds (required: Gitea 1.27 token minting only works via basic auth + Sudo header)",
"binds": [["127.0.0.1", 3042], ["100.111.127.127", 3042]],
"test_mode": false
"test_mode": false,
"rate_limit": {
"enabled": true,
"trust_forwarded_for": false,
"rules": {"/v1/link": [5, 3600], "/v1/repos": [60, 3600]}
}
}
server/granthi_link.py
+244
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@@ -52,6 +52,7 @@ Stdlib only. Python 3.9+.
"""
import base64
import ipaddress
import json
import logging
import os
@@ -61,6 +62,7 @@ import signal
import string
import sys
import threading
import time
import urllib.error
import urllib.request
from datetime import datetime, timezone
@@ -79,6 +81,139 @@ USER_CREATE_CONFLICT = object()
LOGIN_SAFE = re.compile(r"[^a-zA-Z0-9._-]+")
# Rate limiting. /v1/link is the expensive endpoint -- it round-trips Zitadel,
# can CREATE a forge account and always mints a token -- so its default is
# deliberately tight. /v1/repos only spends the caller's own token.
DEFAULT_RATE_RULES = {"/v1/link": (5, 3600), "/v1/repos": (60, 3600)}
MAX_RATE_KEYS = 10000
# --------------------------------------------------------------------------
# Rate limiting
# --------------------------------------------------------------------------
class RateLimiter:
"""Sliding-window limiter keyed by (route, client).
In-process and lock-guarded: granthi-link is ONE ThreadingHTTPServer
process, so a dict is the entire store -- no redis, no shared cache, and
nothing to keep consistent across nodes. If this ever runs multi-process
the limiter must move with it; that is why the store is behind this class
rather than sprinkled through the handler.
"""
def __init__(self, rules=None, max_keys=MAX_RATE_KEYS, clock=None):
self.rules = dict(rules or DEFAULT_RATE_RULES)
# Per-ROUTE budget, not one global table. A shared cap lets a flood of
# cheap /v1/repos keys exhaust the table and lock brand-new /v1/link
# clients out -- turning the fail-closed capacity guard into a
# cross-route denial of service. Each route gets its own space.
self.max_keys = max_keys
self._clock = clock or time.monotonic
self._hits = {route: {} for route in self.rules}
self._lock = threading.Lock()
def check(self, route, client):
"""-> (allowed: bool, retry_after: int). Records the hit when allowed.
Denied requests are NOT recorded: a client that keeps hammering must
not push its own window forward and lock itself out indefinitely.
"""
rule = self.rules.get(route)
if not rule:
return True, 0
limit, window = rule
if limit <= 0: # 0 = endpoint disabled entirely
return False, window
with self._lock:
# Clock read INSIDE the lock: taken outside, two racing threads
# can append out of order, and both hits[0] (retry_after) and
# v[-1] (reclamation age) assume the list is chronological.
now = self._clock()
table = self._hits.setdefault(route, {})
hits = [t for t in table.get(client, ()) if now - t < window]
if len(hits) >= limit:
table[client] = hits
return False, max(1, int(window - (now - hits[0])) + 1)
if client not in table and len(table) >= self.max_keys:
# At capacity, reclaim expired keys first...
self._reclaim_expired(route, now)
if len(table) >= self.max_keys:
# ...and if every window is still live, this is an
# identity flood, not organic load. Evicting here would
# let an attacker reset their own limit on demand, so
# refuse the NEW key instead. Fail closed: /v1/link is
# invite-only and low-volume, so hitting this cap is an
# attack, and turning tokens away beats minting them.
LOG.error("rate limiter at capacity for %s (%d keys) with "
"no expired windows: refusing new client %r",
route, self.max_keys, client)
return False, window
hits.append(now)
table[client] = hits
return True, 0
def _reclaim_expired(self, route, now):
"""Caller holds the lock. Drop only keys whose window has fully
expired -- never a live one, or reclamation becomes the bypass."""
window = self.rules[route][1]
table = self._hits.get(route, {})
dead = [c for c, v in table.items() if not v or now - v[-1] >= window]
for c in dead:
del table[c]
if dead:
LOG.info("rate limiter reclaimed %d expired windows on %s",
len(dead), route)
def client_ip(handler, trust_forwarded_for, trusted_proxies=()):
"""The address to rate-limit on.
Behind cloudflared every request arrives from the tunnel, so limiting on
the socket peer would let one abuser starve everyone. X-Forwarded-For is
client-controlled, though: a caller can prepend anything. Two guards:
1. The header is honored ONLY when the socket peer is itself a configured
trusted proxy. Without that, anyone who can reach the origin directly
-- and the origin also listens on the tailnet -- picks their own
rate-limit key and rotates it at will.
2. A trusted proxy APPENDS the peer it actually saw, so the LAST entry is
the only one the client did not choose. Take that, never the first.
The value must parse as a real IP; junk falls back to the socket peer
rather than becoming a key of its own.
"""
peer = handler.client_address[0]
if not trust_forwarded_for:
return peer
if not _ip_in_any(peer, trusted_proxies):
LOG.warning("X-Forwarded-For ignored: peer %s is not a trusted proxy",
peer)
return peer
xff = handler.headers.get("X-Forwarded-For", "")
parts = [p.strip() for p in xff.split(",") if p.strip()]
if not parts:
return peer
try:
return str(ipaddress.ip_address(parts[-1]))
except ValueError:
LOG.warning("X-Forwarded-For last hop %r is not an IP; using peer",
parts[-1][:60])
return peer
def _ip_in_any(addr, networks):
try:
ip = ipaddress.ip_address(addr)
except ValueError:
return False
for net in networks:
# Pre-parsed at startup by LinkService._parse_trusted_proxies, so a
# malformed entry can never reach here as a silent per-request skip.
if ip.version == net.version and ip in net:
return True
return False
# --------------------------------------------------------------------------
# HTTP helper (patchable in tests)
@@ -203,6 +338,92 @@ class LinkService:
"zitadel_userinfo", "https://id.shre.ai/oidc/v1/userinfo")
self.state = IdentityStore(config.get("state_path", DEFAULT_STATE))
# Rate limiting is ON by default: this endpoint creates accounts and
# mints tokens, so the safe default is limited, and disabling it has
# to be a deliberate config act rather than an omission.
rl = config.get("rate_limit", {})
if rl is None:
rl = {}
if not isinstance(rl, dict):
raise SystemExit("config rate_limit must be an object")
# Real JSON booleans only. `"enabled": null` or `0` must not quietly
# turn limiting off, and the string "false" must not turn XFF trust
# ON (every non-empty string is truthy).
for flag, default in (("enabled", True), ("trust_forwarded_for", False)):
if flag in rl and not isinstance(rl[flag], bool):
raise SystemExit(
f"config rate_limit.{flag} must be true or false, "
f"got {rl[flag]!r}")
self.trust_forwarded_for = rl.get("trust_forwarded_for", False)
self.trusted_proxies = self._parse_trusted_proxies(
rl.get("trusted_proxies"))
if self.trust_forwarded_for and not self.trusted_proxies:
raise SystemExit(
"config rate_limit.trust_forwarded_for requires a non-empty "
"trusted_proxies list -- trusting the header from any peer "
"lets callers choose their own rate-limit key")
if rl.get("enabled", True):
rules = dict(DEFAULT_RATE_RULES)
for route, spec in (rl.get("rules") or {}).items():
# `type(x) is int`, NOT isinstance: bool subclasses int, so
# isinstance lets [5, true] through as a 1-SECOND window --
# an hourly limit silently becomes ~5/sec -- and false in the
# limit slot disables the endpoint.
if (not isinstance(spec, (list, tuple)) or len(spec) != 2
or not all(type(x) is int for x in spec)
or spec[1] <= 0):
# A malformed rule must not silently mean "unlimited".
raise SystemExit(
f"config rate_limit.rules[{route!r}] must be "
f"[max_requests, window_seconds] with window > 0")
rules[route] = (spec[0], spec[1])
self.limiter = RateLimiter(rules)
LOG.info("rate limiting active: %s (trust_forwarded_for=%s, "
"trusted_proxies=%s)",
{k: f"{v[0]}/{v[1]}s" for k, v in rules.items()},
self.trust_forwarded_for, list(self.trusted_proxies))
else:
self.limiter = None
LOG.warning("rate limiting DISABLED by config -- /v1/link will "
"mint tokens without any throttle")
@staticmethod
def _parse_trusted_proxies(raw):
"""Validate at STARTUP, not per request.
This setting gates a spoofable identity, so every failure mode has to
be loud and early: a bare string would be iterated character by
character (each char a "network"), malformed entries would only
surface as a per-request log line, and a wildcard like 0.0.0.0/0 or
::/0 quietly restores "trust X-Forwarded-For from anyone" -- the exact
hole trusted_proxies exists to close.
"""
if raw is None:
return ()
if isinstance(raw, str) or not isinstance(raw, (list, tuple)):
raise SystemExit(
"config rate_limit.trusted_proxies must be a list of CIDRs, "
f"got {type(raw).__name__}")
nets = []
for entry in raw:
if not isinstance(entry, str):
raise SystemExit(
f"config rate_limit.trusted_proxies entry {entry!r} "
"must be a string")
try:
net = ipaddress.ip_network(entry, strict=False)
except ValueError as e:
raise SystemExit(
f"config rate_limit.trusted_proxies entry {entry!r} "
f"is not a valid network: {e}")
if net.prefixlen == 0:
raise SystemExit(
f"config rate_limit.trusted_proxies entry {entry!r} "
"matches every address, which is the same as trusting "
"X-Forwarded-For from any peer -- refusing")
nets.append(net)
return tuple(nets)
def test_mode_enabled(self):
"""Config test_mode is honored ONLY with the env gate also set."""
if not self.cfg.get("test_mode"):
@@ -452,6 +673,29 @@ class Handler(BaseHTTPRequestHandler):
self._send(404, {"error": "not found"})
def do_POST(self):
# Rate-limit BEFORE reading the body or doing any work -- the point is
# to spend nothing on an abusive caller. Same close-the-connection
# treatment the 413 path uses, for the same reason: we are not going
# to drain a body we already decided to reject.
limiter = getattr(self.service, "limiter", None)
if limiter is not None:
who = client_ip(self, self.service.trust_forwarded_for,
self.service.trusted_proxies)
allowed, retry_after = limiter.check(self.path, who)
if not allowed:
LOG.warning("rate limited %s %s (retry after %ss)",
who, self.path, retry_after)
self.close_connection = True
payload = json.dumps({
"error": "rate limit exceeded",
"retry_after": retry_after}).encode()
self.send_response(429)
self.send_header("Content-Type", "application/json")
self.send_header("Retry-After", str(retry_after))
self.send_header("Content-Length", str(len(payload)))
self.end_headers()
self.wfile.write(payload)
return
cl = self.headers.get("Content-Length")
if cl is None:
self.close_connection = True
tests/test_server.py
+369
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@@ -482,3 +482,372 @@ class TestHealth(HandlerTestBase):
if __name__ == "__main__":
unittest.main()
class TestRateLimiterUnit(unittest.TestCase):
"""The limiter in isolation, on a fake clock -- no sleeping in tests."""
def setUp(self):
self.now = 1000.0
self.rl = granthi_link.RateLimiter(
rules={"/v1/link": (3, 60)}, clock=lambda: self.now)
def test_allows_up_to_the_limit_then_denies(self):
for i in range(3):
allowed, _ = self.rl.check("/v1/link", "1.1.1.1")
self.assertTrue(allowed, f"request {i} should pass")
allowed, retry = self.rl.check("/v1/link", "1.1.1.1")
self.assertFalse(allowed)
self.assertGreater(retry, 0)
self.assertLessEqual(retry, 61)
def test_window_slides(self):
for _ in range(3):
self.rl.check("/v1/link", "1.1.1.1")
self.assertFalse(self.rl.check("/v1/link", "1.1.1.1")[0])
self.now += 61
self.assertTrue(self.rl.check("/v1/link", "1.1.1.1")[0])
def test_denied_requests_do_not_extend_the_window(self):
"""A client that keeps hammering must not push its own window
forward and lock itself out forever."""
for _ in range(3):
self.rl.check("/v1/link", "1.1.1.1")
for _ in range(20): # hammer while denied
self.now += 1
self.assertFalse(self.rl.check("/v1/link", "1.1.1.1")[0])
self.now = 1000.0 + 61 # just past the ORIGINAL window
self.assertTrue(self.rl.check("/v1/link", "1.1.1.1")[0])
def test_clients_are_isolated(self):
for _ in range(3):
self.rl.check("/v1/link", "1.1.1.1")
self.assertFalse(self.rl.check("/v1/link", "1.1.1.1")[0])
self.assertTrue(self.rl.check("/v1/link", "2.2.2.2")[0])
def test_routes_are_isolated_and_unknown_routes_pass(self):
for _ in range(3):
self.rl.check("/v1/link", "1.1.1.1")
self.assertFalse(self.rl.check("/v1/link", "1.1.1.1")[0])
self.assertTrue(self.rl.check("/v1/repos", "1.1.1.1")[0])
for _ in range(50):
self.assertTrue(self.rl.check("/health", "1.1.1.1")[0])
def test_zero_limit_disables_the_endpoint(self):
rl = granthi_link.RateLimiter(rules={"/v1/link": (0, 60)},
clock=lambda: self.now)
self.assertFalse(rl.check("/v1/link", "1.1.1.1")[0])
def test_key_store_stays_bounded(self):
rl = granthi_link.RateLimiter(rules={"/v1/link": (5, 60)},
max_keys=50, clock=lambda: self.now)
for i in range(500):
self.now += 0.001
rl.check("/v1/link", f"10.0.{i // 256}.{i % 256}")
self.assertLessEqual(len(rl._hits["/v1/link"]), 50 + 1)
def test_expired_keys_are_reclaimed(self):
rl = granthi_link.RateLimiter(rules={"/v1/link": (5, 60)},
max_keys=10, clock=lambda: self.now)
for i in range(10):
rl.check("/v1/link", f"10.0.0.{i}")
self.now += 120 # everything expires
for i in range(10, 25):
rl.check("/v1/link", f"10.0.0.{i}")
self.assertLessEqual(len(rl._hits["/v1/link"]), 11)
def test_concurrent_checks_never_exceed_the_limit(self):
"""The lock has to actually hold under threads: 40 racing callers
against a limit of 10 must yield exactly 10 allows."""
rl = granthi_link.RateLimiter(rules={"/v1/link": (10, 60)})
results, lock = [], threading.Lock()
def hit():
a, _ = rl.check("/v1/link", "9.9.9.9")
with lock:
results.append(a)
ts = [threading.Thread(target=hit) for _ in range(40)]
for t in ts:
t.start()
for t in ts:
t.join()
self.assertEqual(sum(results), 10)
class _FakeHandler:
def __init__(self, peer, xff=None):
self.client_address = (peer, 12345)
self.headers = {} if xff is None else {"X-Forwarded-For": xff}
if xff is not None:
self.headers = type("H", (), {"get": lambda s, k, d="":
xff if k == "X-Forwarded-For" else d})()
class TestClientIp(unittest.TestCase):
# Pre-parsed, exactly as LinkService._parse_trusted_proxies hands them
# over -- validation happens once at startup, never per request.
PROXY = granthi_link.LinkService._parse_trusted_proxies(["10.0.0.0/8"])
def test_socket_peer_by_default(self):
h = _FakeHandler("5.5.5.5", xff="1.2.3.4")
self.assertEqual(granthi_link.client_ip(h, False, self.PROXY), "5.5.5.5")
def test_trusted_proxy_uses_the_last_hop_not_the_client_supplied_first(self):
"""A caller can PREPEND anything to X-Forwarded-For; a trusted proxy
appends the peer it really saw. Only the last entry is trustworthy."""
h = _FakeHandler("10.0.0.1", xff="1.2.3.4, 203.0.113.9")
self.assertEqual(granthi_link.client_ip(h, True, self.PROXY),
"203.0.113.9")
def test_untrusted_peer_cannot_choose_its_own_key(self):
"""The origin also listens on the tailnet. Anyone reaching it
directly must not be able to pick (and rotate) their rate-limit key
just by sending a header."""
h = _FakeHandler("203.0.113.50", xff="9.9.9.9")
self.assertEqual(granthi_link.client_ip(h, True, self.PROXY),
"203.0.113.50")
def test_non_ip_last_hop_falls_back_to_peer(self):
for junk in ("not-an-ip", "', OR 1=1", "x" * 500, "10.0.0.1:8080"):
with self.subTest(junk=junk):
h = _FakeHandler("10.0.0.1", xff=f"1.2.3.4, {junk}")
self.assertEqual(
granthi_link.client_ip(h, True, self.PROXY), "10.0.0.1")
def test_trusted_proxy_falls_back_when_header_absent(self):
h = _FakeHandler("10.0.0.1")
self.assertEqual(granthi_link.client_ip(h, True, self.PROXY),
"10.0.0.1")
def test_malformed_trusted_proxy_entry_is_rejected_at_startup(self):
"""It never reaches a request: a bad CIDR kills the process rather
than degrading to a per-request log line."""
with self.assertRaises(SystemExit):
granthi_link.LinkService._parse_trusted_proxies(["not-a-cidr"])
def test_v4_peer_does_not_match_a_v6_trusted_net(self):
nets = granthi_link.LinkService._parse_trusted_proxies(["fd00::/8"])
h = _FakeHandler("10.0.0.1", xff="9.9.9.9")
self.assertEqual(granthi_link.client_ip(h, True, nets), "10.0.0.1")
class TestRateLimitConfig(ServiceTestBase):
def _svc(self, rl):
cfg = dict(self.svc.cfg)
cfg["rate_limit"] = rl
return granthi_link.LinkService(cfg)
def test_enabled_by_default_when_key_absent(self):
self.assertIsNotNone(self.svc.limiter)
def test_explicit_disable_is_honored(self):
self.assertIsNone(self._svc({"enabled": False}).limiter)
def test_custom_rule_overrides_default(self):
svc = self._svc({"rules": {"/v1/link": [99, 120]}})
self.assertEqual(svc.limiter.rules["/v1/link"], (99, 120))
def test_malformed_rule_refuses_startup_rather_than_meaning_unlimited(self):
for bad in ({"rules": {"/v1/link": [5]}},
{"rules": {"/v1/link": "5/hour"}},
{"rules": {"/v1/link": [5, 0]}},
{"rules": {"/v1/link": [5, -1]}},
{"rules": {"/v1/link": ["5", "60"]}}):
with self.subTest(cfg=bad):
with self.assertRaises(SystemExit):
self._svc(bad)
class TestRateLimitOverHttp(HandlerTestBase):
"""Proven on the wire: real 429, real Retry-After."""
def setUp(self):
super().setUp()
self.svc.limiter = granthi_link.RateLimiter(rules={"/v1/link": (2, 60)})
def test_third_request_gets_429_with_retry_after(self):
body = json.dumps({"zitadel_access_token": "x"}).encode()
hdrs = {"Content-Length": str(len(body)),
"Content-Type": "application/json"}
for _ in range(2):
st, _ = self.raw_post("/v1/link", body, hdrs)
self.assertNotEqual(st, 429)
conn = http.client.HTTPConnection("127.0.0.1", self.port, timeout=10)
self.addCleanup(conn.close)
conn.request("POST", "/v1/link", body=body, headers=hdrs)
resp = conn.getresponse()
self.assertEqual(resp.status, 429)
self.assertTrue(resp.getheader("Retry-After"))
self.assertIn("rate limit", json.loads(resp.read())["error"])
def test_health_is_never_rate_limited(self):
for _ in range(30):
conn = http.client.HTTPConnection("127.0.0.1", self.port, timeout=10)
conn.request("GET", "/health")
self.assertEqual(conn.getresponse().status, 200)
conn.close()
class TestRateLimitHardening(unittest.TestCase):
"""The four codex [P2] findings, each pinned by a test."""
def test_capacity_fails_closed_instead_of_resetting_a_live_window(self):
"""Evicting a live window would let an attacker who can mint many
distinct keys clear their OWN limit on demand. New keys are refused
instead while every window is still live."""
now = [1000.0]
rl = granthi_link.RateLimiter(rules={"/v1/link": (1, 3600)},
max_keys=5, clock=lambda: now[0])
for i in range(5):
self.assertTrue(rl.check("/v1/link", f"10.0.0.{i}")[0])
victim_hits = list(rl._hits["/v1/link"]["10.0.0.0"])
for i in range(100, 140): # identity flood
allowed, retry = rl.check("/v1/link", f"10.0.1.{i}")
self.assertFalse(allowed)
self.assertGreater(retry, 0)
# the earlier client's window survived the flood untouched
self.assertEqual(rl._hits["/v1/link"]["10.0.0.0"], victim_hits)
self.assertLessEqual(len(rl._hits["/v1/link"]), 5)
def test_capacity_recovers_once_windows_expire(self):
now = [1000.0]
rl = granthi_link.RateLimiter(rules={"/v1/link": (1, 60)},
max_keys=3, clock=lambda: now[0])
for i in range(3):
rl.check("/v1/link", f"10.0.0.{i}")
self.assertFalse(rl.check("/v1/link", "10.0.9.9")[0])
now[0] += 61
self.assertTrue(rl.check("/v1/link", "10.0.9.9")[0])
def test_hits_stay_chronological_under_thread_contention(self):
"""retry_after uses hits[0] and reclamation uses v[-1]; both assume
the list is ordered. Reading the clock outside the lock let racing
threads append out of order."""
rl = granthi_link.RateLimiter(rules={"/v1/link": (500, 3600)})
ts = [threading.Thread(target=lambda: rl.check("/v1/link", "7.7.7.7"))
for _ in range(200)]
for t in ts:
t.start()
for t in ts:
t.join()
hits = rl._hits["/v1/link"]["7.7.7.7"]
self.assertEqual(len(hits), 200)
self.assertEqual(hits, sorted(hits), "timestamps out of order")
class TestRateLimitConfigTypes(ServiceTestBase):
def _svc(self, rl):
cfg = dict(self.svc.cfg)
cfg["rate_limit"] = rl
return granthi_link.LinkService(cfg)
def test_non_boolean_enabled_refuses_startup(self):
"""`"enabled": null` or `0` must not quietly mean unlimited."""
for bad in (None, 0, "", "false", "no", []):
with self.subTest(enabled=bad):
with self.assertRaises(SystemExit):
self._svc({"enabled": bad})
def test_string_false_does_not_enable_forwarded_trust(self):
"""Every non-empty string is truthy -- "false" used to mean True."""
with self.assertRaises(SystemExit):
self._svc({"trust_forwarded_for": "false",
"trusted_proxies": ["10.0.0.0/8"]})
def test_rate_limit_must_be_an_object(self):
for bad in ("yes", 5, ["/v1/link"]):
with self.subTest(rl=bad):
with self.assertRaises(SystemExit):
self._svc(bad)
def test_null_rate_limit_means_defaults_not_disabled(self):
svc = self._svc(None)
self.assertIsNotNone(svc.limiter)
def test_forwarded_trust_without_trusted_proxies_refuses_startup(self):
"""Trusting the header from ANY peer lets callers choose their own
rate-limit key -- that must not be reachable by omission."""
with self.assertRaises(SystemExit):
self._svc({"trust_forwarded_for": True})
with self.assertRaises(SystemExit):
self._svc({"trust_forwarded_for": True, "trusted_proxies": []})
def test_forwarded_trust_with_proxies_is_accepted(self):
svc = self._svc({"trust_forwarded_for": True,
"trusted_proxies": ["10.0.0.0/8", "127.0.0.1/32"]})
self.assertTrue(svc.trust_forwarded_for)
self.assertEqual(len(svc.trusted_proxies), 2)
class TestRateLimitRound2(unittest.TestCase):
"""The three findings from the codex re-review."""
def test_flooding_one_route_cannot_lock_out_another(self):
"""A shared key table turned the fail-closed capacity guard into a
cross-route DoS: cheap /v1/repos keys could exhaust it and shut new
/v1/link clients out. Budgets are per route."""
now = [1000.0]
rl = granthi_link.RateLimiter(
rules={"/v1/link": (5, 3600), "/v1/repos": (60, 3600)},
max_keys=20, clock=lambda: now[0])
for i in range(300): # flood the cheap route
rl.check("/v1/repos", f"10.1.{i // 256}.{i % 256}")
allowed, _ = rl.check("/v1/link", "203.0.113.7") # never-seen client
self.assertTrue(allowed, "/v1/link locked out by a /v1/repos flood")
def test_reclaim_uses_the_right_window_per_route(self):
now = [1000.0]
rl = granthi_link.RateLimiter(
rules={"/v1/link": (1, 3600), "/v1/repos": (1, 10)},
max_keys=2, clock=lambda: now[0])
rl.check("/v1/repos", "a")
rl.check("/v1/repos", "b")
self.assertFalse(rl.check("/v1/repos", "c")[0])
now[0] += 11 # past the /v1/repos window only
self.assertTrue(rl.check("/v1/repos", "c")[0])
class TestRateLimitConfigRound2(ServiceTestBase):
def _svc(self, rl):
cfg = dict(self.svc.cfg)
cfg["rate_limit"] = rl
return granthi_link.LinkService(cfg)
def test_booleans_are_rejected_in_rule_slots(self):
"""bool subclasses int, so isinstance let [5, True] through as a
1-SECOND window -- 5/hour silently became ~5/sec."""
for bad in ([5, True], [True, 3600], [False, 3600], [5, False]):
with self.subTest(rule=bad):
with self.assertRaises(SystemExit):
self._svc({"rules": {"/v1/link": bad}})
def test_valid_int_rule_still_accepted(self):
svc = self._svc({"rules": {"/v1/link": [5, 3600]}})
self.assertEqual(svc.limiter.rules["/v1/link"], (5, 3600))
def test_trusted_proxies_as_bare_string_refuses_startup(self):
"""A string would be iterated character by character, each char
treated as a network."""
with self.assertRaises(SystemExit):
self._svc({"trust_forwarded_for": True,
"trusted_proxies": "10.0.0.0/8"})
def test_wildcard_trusted_proxy_refuses_startup(self):
"""0.0.0.0/0 or ::/0 restores 'trust XFF from anyone' -- the exact
hole trusted_proxies exists to close."""
for wild in ("0.0.0.0/0", "::/0"):
with self.subTest(cidr=wild):
with self.assertRaises(SystemExit):
self._svc({"trust_forwarded_for": True,
"trusted_proxies": [wild]})
def test_non_string_proxy_entry_refuses_startup(self):
with self.assertRaises(SystemExit):
self._svc({"trust_forwarded_for": True,
"trusted_proxies": [10, "10.0.0.0/8"]})
def test_host_address_without_prefix_is_accepted(self):
svc = self._svc({"trust_forwarded_for": True,
"trusted_proxies": ["127.0.0.1", "10.0.0.0/8"]})
self.assertEqual(len(svc.trusted_proxies), 2)