From 03b88d7bc6c9a806b759f7e2ecbe7bb243e96037 Mon Sep 17 00:00:00 2001 From: Aaron Haslett Date: Fri, 30 Nov 2018 18:37:27 +1300 Subject: [PATCH] CVE-2018-14629: Tests to expose regression from dns cname loop fix These tests expose the regression described by Stefan Metzmacher in discussion on the bugzilla paged linked below. BUG: https://bugzilla.samba.org/show_bug.cgi?id=13600 Signed-off-by: Aaron Haslett --- python/samba/tests/dns.py | 76 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 76 insertions(+) diff --git a/python/samba/tests/dns.py b/python/samba/tests/dns.py index e35cded..fb8914d 100644 --- a/python/samba/tests/dns.py +++ b/python/samba/tests/dns.py @@ -869,6 +869,82 @@ class TestComplexQueries(DNSTest): max_recursion_depth = 20 self.assertEquals(len(response.answers), max_recursion_depth) + # Make sure cname limit doesn't count other records. This is a generic + # test called in tests below + def max_rec_test(self, rtype, rec_gen): + name = "limittestrec{}.{}".format(rtype, self.get_dns_domain()) + limit = 20 + num_recs_to_enter = limit + 5 + + for i in range(1, num_recs_to_enter+1): + ip = rec_gen(i) + self.make_dns_update(name, ip, rtype) + + p = self.make_name_packet(dns.DNS_OPCODE_QUERY) + questions = [] + + q = self.make_name_question(name, + rtype, + dns.DNS_QCLASS_IN) + questions.append(q) + self.finish_name_packet(p, questions) + + (response, response_packet) =\ + self.dns_transaction_udp(p, host=self.server_ip) + + self.assertEqual(len(response.answers), num_recs_to_enter) + + def test_record_limit_A(self): + def ip4_gen(i): + return "127.0.0." + str(i) + self.max_rec_test(rtype=dns.DNS_QTYPE_A, rec_gen=ip4_gen) + + def test_record_limit_AAAA(self): + def ip6_gen(i): + return "AAAA:0:0:0:0:0:0:" + str(i) + self.max_rec_test(rtype=dns.DNS_QTYPE_AAAA, rec_gen=ip6_gen) + + def test_record_limit_SRV(self): + def srv_gen(i): + rec = dns.srv_record() + rec.priority = 1 + rec.weight = 1 + rec.port = 92 + rec.target = "srvtestrec" + str(i) + return rec + self.max_rec_test(rtype=dns.DNS_QTYPE_SRV, rec_gen=srv_gen) + + # Same as test_record_limit_A but with a preceding CNAME follow + def test_cname_limit(self): + cname1 = "cnamelimittestrec." + self.get_dns_domain() + cname2 = "cnamelimittestrec2." + self.get_dns_domain() + cname3 = "cnamelimittestrec3." + self.get_dns_domain() + ip_prefix = '127.0.0.' + limit = 20 + num_recs_to_enter = limit + 5 + + self.make_dns_update(cname1, cname2, dnsp.DNS_TYPE_CNAME) + self.make_dns_update(cname2, cname3, dnsp.DNS_TYPE_CNAME) + num_arecs_to_enter = num_recs_to_enter - 2 + for i in range(1, num_arecs_to_enter+1): + ip = ip_prefix + str(i) + self.make_dns_update(cname3, ip, dns.DNS_QTYPE_A) + + p = self.make_name_packet(dns.DNS_OPCODE_QUERY) + questions = [] + + q = self.make_name_question(cname1, + dns.DNS_QTYPE_A, + dns.DNS_QCLASS_IN) + questions.append(q) + self.finish_name_packet(p, questions) + + (response, response_packet) =\ + self.dns_transaction_udp(p, host=self.server_ip) + + self.assertEqual(len(response.answers), num_recs_to_enter) + + class TestInvalidQueries(DNSTest): def setUp(self): super(TestInvalidQueries, self).setUp() -- 2.7.4