fix: restrict Web Push endpoint egress (Closes #653)

tests/test_push_endpoint_policy.py

@@ -0,0 +1,37 @@
+import pytest
+
+from src.push_endpoint_policy import UnsafePushEndpoint, validate_public_push_endpoint
+
+
+@pytest.mark.anyio
+@pytest.mark.parametrize(
+    "address",
+    ["127.0.0.1", "::1", "10.0.0.4", "169.254.169.254", "fc00::1"],
+)
+async def test_push_endpoint_rejects_every_non_public_resolved_address(address):
+    async def resolve(_host, _port):
+        return [address]
+
+    with pytest.raises(UnsafePushEndpoint, match="public Web Push service"):
+        await validate_public_push_endpoint(
+            "https://push.example/device", resolver=resolve
+        )
+
+
+@pytest.mark.anyio
+@pytest.mark.parametrize(
+    "endpoint",
+    [
+        "http://push.example/device",
+        "https://user@push.example/device",
+        "https://push.example:8443/device",
+        "https://push.example:not-a-port/device",
+        "https://push.example/device#fragment",
+    ],
+)
+async def test_push_endpoint_rejects_noncanonical_authorities_without_resolving(endpoint):
+    async def must_not_resolve(_host, _port):
+        raise AssertionError("invalid URL reached DNS")
+
+    with pytest.raises(UnsafePushEndpoint, match="canonical public Web Push"):
+        await validate_public_push_endpoint(endpoint, resolver=must_not_resolve)

tests/test_push_notifications.py

@@ -10,6 +10,15 @@ import pytest
 from src import dashboard_auth, gitea_proxy, main
 from src.push_notifications import PushConfiguration, dispatch_unread_updates
 from src.push_subscription_store import PushSubscriptionStore
+from src.push_endpoint_policy import UnsafePushEndpoint
+
+
+@pytest.fixture(autouse=True)
+def resolve_test_push_endpoints_publicly(monkeypatch):
+    async def accept(endpoint):
+        return endpoint
+
+    monkeypatch.setattr(main, "validate_public_push_endpoint", accept)
 
 
 def test_dispatch_lease_is_exclusive_recoverable_and_owner_fenced(tmp_path):
@@ -508,6 +517,32 @@ async def test_dispatch_removes_an_expired_push_endpoint(tmp_path):
     assert store.is_subscribed("session-a") is False
 
 
+@pytest.mark.anyio
+async def test_dispatch_removes_an_endpoint_that_rebinds_private_without_contacting_it(tmp_path):
+    store = PushSubscriptionStore(tmp_path / "push.sqlite3")
+    store.upsert("unsafe-device", {
+        "endpoint": "https://push.example/rebound",
+        "keys": {"p256dh": "public-key", "auth": "auth-secret"},
+    })
+    contacted = []
+
+    async def unread():
+        return {"items": [{"id": 8}]}
+
+    async def reject_rebound(_endpoint):
+        raise UnsafePushEndpoint("Endpoint must resolve to a public Web Push service")
+
+    async def send(subscription, _payload):
+        contacted.append(subscription["endpoint"])
+
+    config = PushConfiguration("public", "private", "mailto:ops@example.com")
+    assert await dispatch_unread_updates(
+        store, config, unread, send, endpoint_validator=reject_rebound
+    ) == 0
+    assert contacted == []
+    assert store.is_subscribed("unsafe-device") is False
+
+
 @pytest.mark.anyio
 async def test_transient_endpoint_failure_does_not_block_healthy_devices(tmp_path):
     store = PushSubscriptionStore(tmp_path / "push.sqlite3")
@@ -722,6 +757,37 @@ async def test_authenticated_device_can_subscribe_report_status_and_unsubscribe(
     assert (await main.push_status(request))["subscribed"] is False
 
 
+@pytest.mark.anyio
+async def test_subscription_rejects_an_unsafe_endpoint_before_persistence(tmp_path, monkeypatch):
+    store = PushSubscriptionStore(tmp_path / "push.sqlite3")
+    monkeypatch.setattr(main, "_push_subscription_store", store)
+    monkeypatch.setattr(
+        main, "_push_configuration",
+        lambda: PushConfiguration("public", "private", "mailto:ops@example.com"),
+    )
+
+    async def management_id(_session):
+        return "unsafe-device"
+
+    async def reject_private(_endpoint):
+        raise UnsafePushEndpoint("Endpoint must resolve to a public Web Push service")
+
+    monkeypatch.setattr(main.dashboard_auth, "session_management_id", management_id)
+    monkeypatch.setattr(main, "validate_public_push_endpoint", reject_private)
+    request = SimpleNamespace(state=SimpleNamespace(dashboard_session=object()))
+    payload = main.PushSubscriptionPayload(
+        endpoint="https://push.example/device-a",
+        keys={"p256dh": "public-key", "auth": "auth-secret"},
+    )
+
+    with pytest.raises(main.HTTPException) as rejected:
+        await main.subscribe_push(payload, request)
+
+    assert rejected.value.status_code == 422
+    assert rejected.value.detail == "Endpoint must resolve to a public Web Push service"
+    assert store.is_subscribed("unsafe-device") is False
+
+
 @pytest.mark.anyio
 async def test_subscription_baselines_every_revision_from_the_complete_snapshot(tmp_path, monkeypatch):
     store = PushSubscriptionStore(tmp_path / "push.sqlite3")