mirror of
https://gitlab.isc.org/isc-projects/bind9
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0680eb6f64
The ANS servers were not to written to handle NS queries at the QNAME resulting in gratuitious protocol errors that will break tests when NS requests are made for the QNAME.
326 lines
11 KiB
Python
326 lines
11 KiB
Python
# Copyright (C) Internet Systems Consortium, Inc. ("ISC")
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#
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# SPDX-License-Identifier: MPL-2.0
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#
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# This Source Code Form is subject to the terms of the Mozilla Public
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# License, v. 2.0. If a copy of the MPL was not distributed with this
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# file, you can obtain one at https://mozilla.org/MPL/2.0/.
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#
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# See the COPYRIGHT file distributed with this work for additional
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# information regarding copyright ownership.
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from __future__ import print_function
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import os
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import sys
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import signal
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import socket
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import select
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from datetime import datetime, timedelta
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import time
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import functools
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import dns
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import dns.edns
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import dns.flags
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import dns.message
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import dns.query
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import dns.tsig
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import dns.tsigkeyring
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import dns.version
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from dns.edns import *
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from dns.name import *
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from dns.rcode import *
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from dns.rdataclass import *
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from dns.rdatatype import *
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from dns.tsig import *
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# Log query to file
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def logquery(type, qname):
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with open("qlog", "a") as f:
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f.write("%s %s\n", type, qname)
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# DNS 2.0 keyring specifies the algorithm
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try:
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keyring = dns.tsigkeyring.from_text(
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{
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"foo": {os.getenv("DEFAULT_HMAC", "hmac-sha256"), "aaaaaaaaaaaa"},
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"fake": {os.getenv("DEFAULT_HMAC", "hmac-sha256"), "aaaaaaaaaaaa"},
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}
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)
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except:
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keyring = dns.tsigkeyring.from_text({"foo": "aaaaaaaaaaaa", "fake": "aaaaaaaaaaaa"})
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dopass2 = False
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############################################################################
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#
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# This server will serve valid and spoofed answers. A spoofed answer will
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# have the address 10.53.0.10 included.
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#
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# When receiving a query over UDP:
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#
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# A query to "nocookie"/A will result in a spoofed answer with no cookie set.
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# A query to "tcponly"/A will result in a spoofed answer with no cookie set.
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# A query to "withtsig"/A will result in two responses, the first is a spoofed
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# answer that is TSIG signed, the second is a valid answer with a cookie set.
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# A query to anything else will result in a valid answer with a cookie set.
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#
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# When receiving a query over TCP:
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#
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# A query to "nocookie"/A will result in a valid answer with no cookie set.
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# A query to anything else will result in a valid answer with a cookie set.
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#
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############################################################################
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def create_response(msg, tcp, first, ns10):
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global dopass2
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m = dns.message.from_wire(msg, keyring=keyring)
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qname = m.question[0].name.to_text()
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lqname = qname.lower()
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labels = lqname.split(".")
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rrtype = m.question[0].rdtype
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typename = dns.rdatatype.to_text(rrtype)
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with open("query.log", "a") as f:
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f.write("%s %s\n" % (typename, qname))
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print("%s %s" % (typename, qname), end=" ")
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r = dns.message.make_response(m)
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r.set_rcode(NOERROR)
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if rrtype == A:
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# exempt potential nameserver A records.
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if labels[0] == "ns" and ns10:
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r.answer.append(dns.rrset.from_text(qname, 1, IN, A, "10.53.0.10"))
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else:
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r.answer.append(dns.rrset.from_text(qname, 1, IN, A, "10.53.0.9"))
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if not tcp and labels[0] == "nocookie":
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r.answer.append(dns.rrset.from_text(qname, 1, IN, A, "10.53.0.10"))
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if not tcp and labels[0] == "tcponly":
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r.answer.append(dns.rrset.from_text(qname, 1, IN, A, "10.53.0.10"))
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if first and not tcp and labels[0] == "withtsig":
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r.answer.append(dns.rrset.from_text(qname, 1, IN, A, "10.53.0.10"))
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dopass2 = True
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elif rrtype == NS:
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length = len(labels)
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if length == 2:
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r.answer.append(dns.rrset.from_text(qname, 1, IN, NS, "ns." + qname))
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if ns10:
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r.additional.append(
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dns.rrset.from_text("ns." + qname, 1, IN, A, "10.53.0.10")
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)
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else:
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r.additional.append(
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dns.rrset.from_text("ns." + qname, 1, IN, A, "10.53.0.9")
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)
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else:
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tld = ".".join(labels[length - 2 :])
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r.authority.append(dns.rrset.from_text(tld, 2, IN, SOA, ". . 0 0 0 0 2"))
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elif rrtype == SOA:
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r.answer.append(dns.rrset.from_text(qname, 2, IN, SOA, ". . 0 0 0 0 2"))
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else:
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r.authority.append(dns.rrset.from_text(qname, 2, IN, SOA, ". . 0 0 0 0 2"))
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# Add a server cookie to the response
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if labels[0] != "nocookie" or rrtype != A:
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for o in m.options:
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if o.otype == 10: # Use 10 instead of COOKIE
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if first and labels[0] == "withtsig" and not tcp and rrtype == A:
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r.use_tsig(
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keyring=keyring,
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keyname=dns.name.from_text("fake"),
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algorithm=HMAC_SHA256,
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)
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elif labels[0] != "tcponly" or tcp or rrtype != A:
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cookie = o
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try:
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if len(o.server) == 0:
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cookie.server = o.client
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except AttributeError: # dnspython<2.7.0 compat
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if len(o.data) == 8:
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cookie.data = o.data + o.data
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else:
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cookie.data = o.data
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r.use_edns(options=[cookie])
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r.flags |= dns.flags.AA
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return r
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def sigterm(signum, frame):
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print("Shutting down now...")
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os.remove("ans.pid")
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running = False
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sys.exit(0)
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############################################################################
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# Main
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#
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# Set up responder and control channel, open the pid file, and start
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# the main loop, listening for queries on the query channel or commands
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# on the control channel and acting on them.
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############################################################################
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ip4_addr1 = "10.53.0.9"
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ip4_addr2 = "10.53.0.10"
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ip6_addr1 = "fd92:7065:b8e:ffff::9"
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ip6_addr2 = "fd92:7065:b8e:ffff::10"
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try:
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port = int(os.environ["PORT"])
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except:
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port = 5300
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query4_udp1 = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
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query4_udp1.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
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query4_udp1.bind((ip4_addr1, port))
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query4_tcp1 = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
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query4_tcp1.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
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query4_tcp1.bind((ip4_addr1, port))
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query4_tcp1.listen(1)
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query4_tcp1.settimeout(1)
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query4_udp2 = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
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query4_udp2.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
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query4_udp2.bind((ip4_addr2, port))
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query4_tcp2 = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
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query4_tcp2.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
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query4_tcp2.bind((ip4_addr2, port))
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query4_tcp2.listen(1)
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query4_tcp2.settimeout(1)
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havev6 = True
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query6_udp1 = None
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query6_udp2 = None
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query6_tcp1 = None
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query6_tcp2 = None
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try:
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query6_udp1 = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM)
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query6_udp1.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
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query6_udp1.bind((ip6_addr1, port))
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query6_tcp1 = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
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query6_tcp1.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
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query6_tcp1.bind((ip6_addr1, port))
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query6_tcp1.listen(1)
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query6_tcp1.settimeout(1)
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query6_udp2 = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM)
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query6_udp2.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
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query6_udp2.bind((ip6_addr2, port))
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query6_tcp2 = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
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query6_tcp2.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
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query6_tcp2.bind((ip6_addr2, port))
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query6_tcp2.listen(1)
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query6_tcp2.settimeout(1)
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except:
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if query6_udp1 != None:
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query6_udp1.close()
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if query6_tcp1 != None:
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query6_tcp1.close()
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if query6_udp2 != None:
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query6_udp2.close()
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if query6_tcp2 != None:
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query6_tcp2.close()
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havev6 = False
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signal.signal(signal.SIGTERM, sigterm)
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f = open("ans.pid", "w")
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pid = os.getpid()
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print(pid, file=f)
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f.close()
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running = True
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print("Using DNS version %s" % dns.version.version)
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print("Listening on %s port %d" % (ip4_addr1, port))
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print("Listening on %s port %d" % (ip4_addr2, port))
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if havev6:
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print("Listening on %s port %d" % (ip6_addr1, port))
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print("Listening on %s port %d" % (ip6_addr2, port))
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print("Ctrl-c to quit")
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if havev6:
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input = [
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query4_udp1,
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query6_udp1,
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query4_tcp1,
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query6_tcp1,
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query4_udp2,
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query6_udp2,
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query4_tcp2,
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query6_tcp2,
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]
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else:
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input = [query4_udp1, query4_tcp1, query4_udp2, query4_tcp2]
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while running:
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try:
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inputready, outputready, exceptready = select.select(input, [], [])
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except select.error as e:
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break
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except socket.error as e:
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break
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except KeyboardInterrupt:
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break
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for s in inputready:
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ns10 = False
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if s == query4_udp1 or s == query6_udp1 or s == query4_udp2 or s == query6_udp2:
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if s == query4_udp1 or s == query6_udp1:
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print(
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"UDP Query received on %s"
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% (ip4_addr1 if s == query4_udp1 else ip6_addr1),
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end=" ",
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)
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if s == query4_udp2 or s == query6_udp2:
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print(
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"UDP Query received on %s"
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% (ip4_addr2 if s == query4_udp2 else ip6_addr2),
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end=" ",
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)
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ns10 = True
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# Handle incoming queries
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msg = s.recvfrom(65535)
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dopass2 = False
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rsp = create_response(msg[0], False, True, ns10)
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print(dns.rcode.to_text(rsp.rcode()))
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s.sendto(rsp.to_wire(), msg[1])
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if dopass2:
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print("Sending second UDP response without TSIG", end=" ")
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rsp = create_response(msg[0], False, False, ns10)
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s.sendto(rsp.to_wire(), msg[1])
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print(dns.rcode.to_text(rsp.rcode()))
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if s == query4_tcp1 or s == query6_tcp1 or s == query4_tcp2 or s == query6_tcp2:
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try:
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(cs, _) = s.accept()
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if s == query4_tcp1 or s == query6_tcp1:
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print(
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"TCP Query received on %s"
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% (ip4_addr1 if s == query4_tcp1 else ip6_addr1),
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end=" ",
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)
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if s == query4_tcp2 or s == query6_tcp2:
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print(
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"TCP Query received on %s"
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% (ip4_addr2 if s == query4_tcp2 else ip6_addr2),
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end=" ",
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)
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ns10 = True
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# get TCP message length
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buf = cs.recv(2)
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length = struct.unpack(">H", buf[:2])[0]
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# grep DNS message
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msg = cs.recv(length)
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rsp = create_response(msg, True, True, ns10)
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print(dns.rcode.to_text(rsp.rcode()))
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wire = rsp.to_wire()
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cs.send(struct.pack(">H", len(wire)))
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cs.send(wire)
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cs.close()
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except s.timeout:
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pass
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if not running:
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break
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