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chg: test: Use isctest.asyncserver in the "cookie" test

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Replace the custom DNS servers in the "cookie" system test with new code
based on the isctest.asyncserver module. The convoluted test logic is
split into multiple response handlers which are shared between the two
servers.

Behavior change: returned SOA records have the zone name set properly.

Merge branch 'stepan/cookie-asyncserver' into 'main'

See merge request isc-projects/bind9!10691
This commit is contained in:
Štěpán Balážik 2025-10-29 16:06:26 +00:00
commit 1ff1c4d042
3 changed files with 239 additions and 310 deletions
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20
bin/tests/system/cookie/ans10/ans.py Normal file
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# Copyright (C) Internet Systems Consortium, Inc. ("ISC")
#
# SPDX-License-Identifier: MPL-2.0
#
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, you can obtain one at https://mozilla.org/MPL/2.0/.
#
# See the COPYRIGHT file distributed with this work for additional
# information regarding copyright ownership.
from cookie_ans import cookie_server
def main() -> None:
cookie_server(evil=True).run()
if __name__ == "__main__":
main()

315
bin/tests/system/cookie/ans9/ans.py
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@ -9,317 +9,12 @@
# See the COPYRIGHT file distributed with this work for additional
# information regarding copyright ownership.
from __future__ import print_function
import os
import sys
import signal
import socket
import select
from datetime import datetime, timedelta
import time
import functools
import dns
import dns.edns
import dns.flags
import dns.message
import dns.query
import dns.tsig
import dns.tsigkeyring
import dns.version
from dns.edns import *
from dns.name import *
from dns.rcode import *
from dns.rdataclass import *
from dns.rdatatype import *
from dns.tsig import *
from cookie_ans import cookie_server
# Log query to file
def logquery(type, qname):
with open("qlog", "a") as f:
f.write("%s %s\n", type, qname)
def main() -> None:
cookie_server(evil=False).run()
# DNS 2.0 keyring specifies the algorithm
try:
keyring = dns.tsigkeyring.from_text(
{
"foo": {os.getenv("DEFAULT_HMAC", "hmac-sha256"), "aaaaaaaaaaaa"},
"fake": {os.getenv("DEFAULT_HMAC", "hmac-sha256"), "aaaaaaaaaaaa"},
}
)
except:
keyring = dns.tsigkeyring.from_text({"foo": "aaaaaaaaaaaa", "fake": "aaaaaaaaaaaa"})
dopass2 = False
############################################################################
#
# This server will serve valid and spoofed answers. A spoofed answer will
# have the address 10.53.0.10 included.
#
# When receiving a query over UDP:
#
# A query to "nocookie"/A will result in a spoofed answer with no cookie set.
# A query to "tcponly"/A will result in a spoofed answer with no cookie set.
# A query to "withtsig"/A will result in two responses, the first is a spoofed
# answer that is TSIG signed, the second is a valid answer with a cookie set.
# A query to anything else will result in a valid answer with a cookie set.
#
# When receiving a query over TCP:
#
# A query to "nocookie"/A will result in a valid answer with no cookie set.
# A query to anything else will result in a valid answer with a cookie set.
#
############################################################################
def create_response(msg, tcp, first, ns10):
global dopass2
m = dns.message.from_wire(msg, keyring=keyring)
qname = m.question[0].name.to_text()
lqname = qname.lower()
labels = lqname.split(".")
rrtype = m.question[0].rdtype
typename = dns.rdatatype.to_text(rrtype)
with open("query.log", "a") as f:
f.write("%s %s\n" % (typename, qname))
print("%s %s" % (typename, qname), end=" ")
r = dns.message.make_response(m)
r.set_rcode(NOERROR)
if rrtype == A:
# exempt potential nameserver A records.
if labels[0] == "ns" and ns10:
r.answer.append(dns.rrset.from_text(qname, 1, IN, A, "10.53.0.10"))
else:
r.answer.append(dns.rrset.from_text(qname, 1, IN, A, "10.53.0.9"))
if not tcp and labels[0] == "nocookie":
r.answer.append(dns.rrset.from_text(qname, 1, IN, A, "10.53.0.10"))
if not tcp and labels[0] == "tcponly":
r.answer.append(dns.rrset.from_text(qname, 1, IN, A, "10.53.0.10"))
if first and not tcp and labels[0] == "withtsig":
r.answer.append(dns.rrset.from_text(qname, 1, IN, A, "10.53.0.10"))
dopass2 = True
elif rrtype == NS:
length = len(labels)
if length == 2:
r.answer.append(dns.rrset.from_text(qname, 1, IN, NS, "ns." + qname))
if ns10:
r.additional.append(
dns.rrset.from_text("ns." + qname, 1, IN, A, "10.53.0.10")
)
else:
r.additional.append(
dns.rrset.from_text("ns." + qname, 1, IN, A, "10.53.0.9")
)
else:
tld = ".".join(labels[length - 2 :])
r.authority.append(dns.rrset.from_text(tld, 2, IN, SOA, ". . 0 0 0 0 2"))
elif rrtype == SOA:
r.answer.append(dns.rrset.from_text(qname, 2, IN, SOA, ". . 0 0 0 0 2"))
else:
r.authority.append(dns.rrset.from_text(qname, 2, IN, SOA, ". . 0 0 0 0 2"))
# Add a server cookie to the response
if labels[0] != "nocookie" or rrtype != A:
for o in m.options:
if o.otype == 10: # Use 10 instead of COOKIE
if first and labels[0] == "withtsig" and not tcp and rrtype == A:
r.use_tsig(
keyring=keyring,
keyname=dns.name.from_text("fake"),
algorithm=HMAC_SHA256,
)
elif labels[0] != "tcponly" or tcp or rrtype != A:
cookie = o
try:
if len(o.server) == 0:
cookie.server = o.client
except AttributeError: # dnspython<2.7.0 compat
if len(o.data) == 8:
cookie.data = o.data + o.data
else:
cookie.data = o.data
r.use_edns(options=[cookie])
r.flags |= dns.flags.AA
return r
def sigterm(signum, frame):
print("Shutting down now...")
os.remove("ans.pid")
running = False
sys.exit(0)
############################################################################
# Main
#
# Set up responder and control channel, open the pid file, and start
# the main loop, listening for queries on the query channel or commands
# on the control channel and acting on them.
############################################################################
ip4_addr1 = "10.53.0.9"
ip4_addr2 = "10.53.0.10"
ip6_addr1 = "fd92:7065:b8e:ffff::9"
ip6_addr2 = "fd92:7065:b8e:ffff::10"
try:
port = int(os.environ["PORT"])
except:
port = 5300
query4_udp1 = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
query4_udp1.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
query4_udp1.bind((ip4_addr1, port))
query4_tcp1 = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
query4_tcp1.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
query4_tcp1.bind((ip4_addr1, port))
query4_tcp1.listen(1)
query4_tcp1.settimeout(1)
query4_udp2 = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
query4_udp2.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
query4_udp2.bind((ip4_addr2, port))
query4_tcp2 = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
query4_tcp2.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
query4_tcp2.bind((ip4_addr2, port))
query4_tcp2.listen(1)
query4_tcp2.settimeout(1)
havev6 = True
query6_udp1 = None
query6_udp2 = None
query6_tcp1 = None
query6_tcp2 = None
try:
query6_udp1 = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM)
query6_udp1.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
query6_udp1.bind((ip6_addr1, port))
query6_tcp1 = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
query6_tcp1.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
query6_tcp1.bind((ip6_addr1, port))
query6_tcp1.listen(1)
query6_tcp1.settimeout(1)
query6_udp2 = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM)
query6_udp2.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
query6_udp2.bind((ip6_addr2, port))
query6_tcp2 = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
query6_tcp2.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
query6_tcp2.bind((ip6_addr2, port))
query6_tcp2.listen(1)
query6_tcp2.settimeout(1)
except:
if query6_udp1 != None:
query6_udp1.close()
if query6_tcp1 != None:
query6_tcp1.close()
if query6_udp2 != None:
query6_udp2.close()
if query6_tcp2 != None:
query6_tcp2.close()
havev6 = False
signal.signal(signal.SIGTERM, sigterm)
f = open("ans.pid", "w")
pid = os.getpid()
print(pid, file=f)
f.close()
running = True
print("Using DNS version %s" % dns.version.version)
print("Listening on %s port %d" % (ip4_addr1, port))
print("Listening on %s port %d" % (ip4_addr2, port))
if havev6:
print("Listening on %s port %d" % (ip6_addr1, port))
print("Listening on %s port %d" % (ip6_addr2, port))
print("Ctrl-c to quit")
if havev6:
input = [
query4_udp1,
query6_udp1,
query4_tcp1,
query6_tcp1,
query4_udp2,
query6_udp2,
query4_tcp2,
query6_tcp2,
]
else:
input = [query4_udp1, query4_tcp1, query4_udp2, query4_tcp2]
while running:
try:
inputready, outputready, exceptready = select.select(input, [], [])
except select.error as e:
break
except socket.error as e:
break
except KeyboardInterrupt:
break
for s in inputready:
ns10 = False
if s == query4_udp1 or s == query6_udp1 or s == query4_udp2 or s == query6_udp2:
if s == query4_udp1 or s == query6_udp1:
print(
"UDP Query received on %s"
% (ip4_addr1 if s == query4_udp1 else ip6_addr1),
end=" ",
)
if s == query4_udp2 or s == query6_udp2:
print(
"UDP Query received on %s"
% (ip4_addr2 if s == query4_udp2 else ip6_addr2),
end=" ",
)
ns10 = True
# Handle incoming queries
msg = s.recvfrom(65535)
dopass2 = False
rsp = create_response(msg[0], False, True, ns10)
print(dns.rcode.to_text(rsp.rcode()))
s.sendto(rsp.to_wire(), msg[1])
if dopass2:
print("Sending second UDP response without TSIG", end=" ")
rsp = create_response(msg[0], False, False, ns10)
s.sendto(rsp.to_wire(), msg[1])
print(dns.rcode.to_text(rsp.rcode()))
if s == query4_tcp1 or s == query6_tcp1 or s == query4_tcp2 or s == query6_tcp2:
try:
(cs, _) = s.accept()
if s == query4_tcp1 or s == query6_tcp1:
print(
"TCP Query received on %s"
% (ip4_addr1 if s == query4_tcp1 else ip6_addr1),
end=" ",
)
if s == query4_tcp2 or s == query6_tcp2:
print(
"TCP Query received on %s"
% (ip4_addr2 if s == query4_tcp2 else ip6_addr2),
end=" ",
)
ns10 = True
# get TCP message length
buf = cs.recv(2)
length = struct.unpack(">H", buf[:2])[0]
# grep DNS message
msg = cs.recv(length)
rsp = create_response(msg, True, True, ns10)
print(dns.rcode.to_text(rsp.rcode()))
wire = rsp.to_wire()
cs.send(struct.pack(">H", len(wire)))
cs.send(wire)
cs.close()
except s.timeout:
pass
if not running:
break
if __name__ == "__main__":
main()

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bin/tests/system/cookie/cookie_ans.py Normal file
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# Copyright (C) Internet Systems Consortium, Inc. ("ISC")
#
# SPDX-License-Identifier: MPL-2.0
#
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, you can obtain one at https://mozilla.org/MPL/2.0/.
#
# See the COPYRIGHT file distributed with this work for additional
# information regarding copyright ownership.
from typing import AsyncGenerator
import dns
import dns.tsigkeyring
from isctest.asyncserver import (
AsyncDnsServer,
ResponseHandler,
DnsResponseSend,
DnsProtocol,
QueryContext,
)
from isctest.name import prepend_label
from isctest.vars.algorithms import ALG_VARS
KEYRING = dns.tsigkeyring.from_text(
{
"foo": (ALG_VARS["DEFAULT_HMAC"], "aaaaaaaaaaaa"),
"fake": (ALG_VARS["DEFAULT_HMAC"], "aaaaaaaaaaaa"),
}
)
def _reparse_with_keyring(qctx: QueryContext) -> None:
"""
`isctest.asyncserver` doesn't support TSIG signing and validation properly
and hacks around it. However, here we need to be able to sign responses with
TSIG, so we reparse the query and recreate the response stub here.
"""
qctx.query = dns.message.from_wire(qctx.query.to_wire(), keyring=KEYRING)
qctx.response = dns.message.make_response(qctx.query)
def _first_label(qctx: QueryContext) -> str:
return qctx.qname.labels[0].decode("ascii")
def _add_cookie(qctx: QueryContext) -> None:
for o in qctx.query.options:
if o.otype == dns.edns.OptionType.COOKIE:
cookie = o
try:
if len(cookie.server) == 0:
cookie.server = cookie.client
except AttributeError: # dnspython<2.7.0 compat
if len(o.data) == 8:
cookie.data *= 2
qctx.response.use_edns(options=[cookie])
return
def _tld(qctx: QueryContext) -> dns.name.Name:
return dns.name.Name(qctx.qname.labels[-2:])
def _soa(qctx: QueryContext) -> dns.rrset.RRset:
return dns.rrset.from_text(
_tld(qctx), 2, dns.rdataclass.IN, dns.rdatatype.SOA, ". . 0 0 0 0 2"
)
def _ns_name(qctx: QueryContext) -> dns.name.Name:
return prepend_label("ns", _tld(qctx))
def _ns(qctx: QueryContext) -> dns.rrset.RRset:
return dns.rrset.from_text(
qctx.qname,
1,
dns.rdataclass.IN,
dns.rdatatype.NS,
_ns_name(qctx).to_text(),
)
def _legit_a(qctx: QueryContext) -> dns.rrset.RRset:
return dns.rrset.from_text(
qctx.qname, 1, dns.rdataclass.IN, dns.rdatatype.A, "10.53.0.9"
)
def _spoofed_a(qctx: QueryContext) -> dns.rrset.RRset:
return dns.rrset.from_text(
qctx.qname, 1, dns.rdataclass.IN, dns.rdatatype.A, "10.53.0.10"
)
class _SpoofableHandler(ResponseHandler):
def __init__(self, evil_server: bool) -> None:
self.evil_server = evil_server
class NsHandler(_SpoofableHandler):
def match(self, qctx: QueryContext) -> bool:
return qctx.qtype == dns.rdatatype.NS and qctx.qname == _tld(qctx)
async def get_responses(
self, qctx: QueryContext
) -> AsyncGenerator[DnsResponseSend, None]:
_reparse_with_keyring(qctx)
_add_cookie(qctx)
qctx.response.answer.append(_ns(qctx))
if self.evil_server:
qctx.response.authority.append(_spoofed_a(qctx))
else:
qctx.response.authority.append(_legit_a(qctx))
yield DnsResponseSend(qctx.response, authoritative=True)
class GlueHandler(_SpoofableHandler):
def match(self, qctx: QueryContext) -> bool:
return qctx.qtype == dns.rdatatype.A and qctx.qname == _ns_name(qctx)
async def get_responses(
self, qctx: QueryContext
) -> AsyncGenerator[DnsResponseSend, None]:
_reparse_with_keyring(qctx)
_add_cookie(qctx)
if self.evil_server:
qctx.response.answer.append(_spoofed_a(qctx))
else:
qctx.response.answer.append(_legit_a(qctx))
yield DnsResponseSend(qctx.response, authoritative=True)
class TcpAHandler(ResponseHandler):
def match(self, qctx: QueryContext) -> bool:
return qctx.qtype == dns.rdatatype.A and qctx.protocol == DnsProtocol.TCP
async def get_responses(
self, qctx: QueryContext
) -> AsyncGenerator[DnsResponseSend, None]:
_reparse_with_keyring(qctx)
if _first_label(qctx) != "nocookie":
_add_cookie(qctx)
qctx.response.answer.append(_legit_a(qctx))
yield DnsResponseSend(qctx.response, authoritative=True)
class WithtsigUdpAHandler(ResponseHandler):
def match(self, qctx: QueryContext) -> bool:
return (
qctx.qtype == dns.rdatatype.A
and qctx.protocol == DnsProtocol.UDP
and _first_label(qctx) == "withtsig"
)
async def get_responses(
self, qctx: QueryContext
) -> AsyncGenerator[DnsResponseSend, None]:
_reparse_with_keyring(qctx)
qctx.response.answer.append(_legit_a(qctx))
qctx.response.answer.append(_spoofed_a(qctx))
qctx.response.use_tsig(keyring=KEYRING, keyname="fake")
yield DnsResponseSend(qctx.response, authoritative=True)
_reparse_with_keyring(qctx)
_add_cookie(qctx)
qctx.response.answer.append(_legit_a(qctx))
yield DnsResponseSend(qctx.response, authoritative=True)
class UdpAHandler(ResponseHandler):
def match(self, qctx: QueryContext) -> bool:
return qctx.qtype == dns.rdatatype.A and qctx.protocol == DnsProtocol.UDP
async def get_responses(
self, qctx: QueryContext
) -> AsyncGenerator[DnsResponseSend, None]:
_reparse_with_keyring(qctx)
qctx.response.answer.append(_legit_a(qctx))
if _first_label(qctx) not in ("nocookie", "tcponly"):
_add_cookie(qctx)
else:
qctx.response.answer.append(_spoofed_a(qctx))
yield DnsResponseSend(qctx.response, authoritative=True)
class FallbackHandler(ResponseHandler):
async def get_responses(
self, qctx: QueryContext
) -> AsyncGenerator[DnsResponseSend, None]:
_reparse_with_keyring(qctx)
_add_cookie(qctx)
if qctx.qtype == dns.rdatatype.SOA:
qctx.response.answer.append(_soa(qctx))
else:
qctx.response.authority.append(_soa(qctx))
yield DnsResponseSend(qctx.response, authoritative=True)
def cookie_server(evil: bool) -> AsyncDnsServer:
server = AsyncDnsServer(acknowledge_tsig_dnspython_hacks=True)
server.install_response_handler(NsHandler(evil))
server.install_response_handler(GlueHandler(evil))
server.install_response_handler(TcpAHandler())
server.install_response_handler(WithtsigUdpAHandler())
server.install_response_handler(UdpAHandler())
server.install_response_handler(FallbackHandler())
return server