From ae4ce47f0a6cd6e83b0de1c689b834ba374409f5 Mon Sep 17 00:00:00 2001
From: Jean-Paul Calderone <exarkun@twistedmatrix.com>
Date: Fri, 15 Nov 2019 12:36:32 -0500
Subject: [PATCH] Test and implement "double-spend" detection/reporting in the
redeemer
---
src/_zkapauthorizer/controller.py | 4 ++
src/_zkapauthorizer/tests/test_controller.py | 57 ++++++++++++++++++--
2 files changed, 57 insertions(+), 4 deletions(-)
diff --git a/src/_zkapauthorizer/controller.py b/src/_zkapauthorizer/controller.py
index b1c4d4b..d852606 100644
--- a/src/_zkapauthorizer/controller.py
+++ b/src/_zkapauthorizer/controller.py
@@ -325,6 +325,10 @@ class RistrettoRedeemer(object):
self._log.failure("Parsing redeem response failed", response=response)
raise
+ if result.get(u"failed", False):
+ if result.get(u"reason", None) == u"double-spend":
+ raise AlreadySpent(voucher)
+
self._log.info("Redeemed: {public-key} {proof} {signatures}", **result)
marshaled_signed_tokens = result[u"signatures"]
diff --git a/src/_zkapauthorizer/tests/test_controller.py b/src/_zkapauthorizer/tests/test_controller.py
index 17876ca..bccd896 100644
--- a/src/_zkapauthorizer/tests/test_controller.py
+++ b/src/_zkapauthorizer/tests/test_controller.py
@@ -76,6 +76,7 @@ from twisted.web.resource import (
)
from twisted.web.http import (
UNSUPPORTED_MEDIA_TYPE,
+ BAD_REQUEST,
)
from treq.testing import (
StubTreq,
@@ -98,18 +99,19 @@ from ..controller import (
DoubleSpentRedeemer,
RistrettoRedeemer,
PaymentController,
+ AlreadySpent,
)
from ..model import (
memory_connect,
VoucherStore,
- Voucher,
UnblindedToken,
)
from .strategies import (
tahoe_configs,
vouchers,
+ voucher_objects,
)
from .matchers import (
Provides,
@@ -218,7 +220,7 @@ class RistrettoRedeemerTests(TestCase):
Provides([IRedeemer]),
)
- @given(vouchers().map(Voucher), integers(min_value=1, max_value=100))
+ @given(voucher_objects(), integers(min_value=1, max_value=100))
def test_good_ristretto_redemption(self, voucher, num_tokens):
"""
If the issuer returns a successful result then
@@ -246,7 +248,33 @@ class RistrettoRedeemerTests(TestCase):
),
)
- @given(vouchers().map(Voucher), integers(min_value=1, max_value=100))
+ @given(voucher_objects(), integers(min_value=1, max_value=100))
+ def test_redemption_denied_alreadyspent(self, voucher, num_tokens):
+ """
+ If the issuer declines to allow the voucher to be redeemed and gives a
+ reason that the voucher has already been spent, ``RistrettoRedeem``
+ returns a ``Deferred`` that fires with a ``Failure`` wrapping
+ ``AlreadySpent``.
+ """
+ issuer = AlreadySpentRedemption()
+ treq = treq_for_loopback_ristretto(issuer)
+ redeemer = RistrettoRedeemer(treq, NOWHERE)
+ random_tokens = redeemer.random_tokens_for_voucher(voucher, num_tokens)
+ d = redeemer.redeem(
+ voucher,
+ random_tokens,
+ )
+ self.assertThat(
+ d,
+ failed(
+ AfterPreprocessing(
+ lambda f: f.value,
+ IsInstance(AlreadySpent),
+ ),
+ ),
+ )
+
+ @given(voucher_objects(), integers(min_value=1, max_value=100))
def test_bad_ristretto_redemption(self, voucher, num_tokens):
"""
If the issuer returns a successful result with an invalid proof then
@@ -279,7 +307,7 @@ class RistrettoRedeemerTests(TestCase):
),
)
- @given(vouchers().map(Voucher), integers(min_value=1, max_value=100))
+ @given(voucher_objects(), integers(min_value=1, max_value=100))
def test_ristretto_pass_construction(self, voucher, num_tokens):
"""
The passes constructed using unblinded tokens and messages pass the
@@ -393,6 +421,20 @@ def stub_agent():
return _StubAgent()
+class AlreadySpentRedemption(Resource):
+ """
+ An ``AlreadySpentRedemption`` simulates the Ristretto redemption server
+ but always refuses to allow vouchers to be redeemed and reports an error
+ that the voucher has already been redeemed.
+ """
+ def render_POST(self, request):
+ if request.requestHeaders.getRawHeaders(b"content-type") != ["application/json"]:
+ return bad_content_type(request)
+
+ return bad_request(request, {u"failed": True, u"reason": u"double-spend"})
+
+
+
class RistrettoRedemption(Resource):
def __init__(self, signing_key):
Resource.__init__(self)
@@ -438,6 +480,13 @@ class RistrettoRedemption(Resource):
})
+def bad_request(request, body_object):
+ request.setResponseCode(BAD_REQUEST)
+ request.setHeader(b"content-type", b"application/json")
+ request.write(dumps(body_object))
+ return b""
+
+
def bad_content_type(request):
return ErrorPage(
UNSUPPORTED_MEDIA_TYPE,
--
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