Kea: zone_checker.cc Source File

| Kea 2.2.0

zone_checker.cc
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1// Copyright (C) 2012-2020 Internet Systems Consortium, Inc. ("ISC")
2//
3// This Source Code Form is subject to the terms of the Mozilla Public
4// License, v. 2.0. If a copy of the MPL was not distributed with this
5// file, You can obtain one at http://mozilla.org/MPL/2.0/.
6
7#include <config.h>
8
9#include <dns/zone_checker.h>
10
11#include <dns/name.h>
12#include <dns/rdataclass.h>
13#include <dns/rrclass.h>
14#include <dns/rrtype.h>
15#include <dns/rrset.h>
16#include <dns/rrset_collection_base.h>
17
18#include <boost/lexical_cast.hpp>
19
20#include <functional>
21#include <string>
22
23using boost::lexical_cast;
24using std::string;
25namespace ph = std::placeholders;
26
27namespace isc {
28namespace dns {
29
30namespace {
31std::string
32zoneText(const Name& zone_name, const RRClass& zone_class) {
33 return (zone_name.toText(true) + "/" + zone_class.toText());
34}
35
36void
37checkSOA(const Name& zone_name, const RRClass& zone_class,
38 const RRsetCollectionBase& zone_rrsets,
39 ZoneCheckerCallbacks& callback) {
40 ConstRRsetPtr rrset =
41 zone_rrsets.find(zone_name, zone_class, RRType::SOA());
42 size_t count = 0;
43 if (rrset) {
44 for (RdataIteratorPtr rit = rrset->getRdataIterator();
45 !rit->isLast();
46 rit->next(), ++count) {
47 if (dynamic_cast<const rdata::generic::SOA*>(&rit->getCurrent()) ==
48 NULL) {
49 isc_throw(Unexpected, "Zone checker found bad RDATA in SOA");
50 }
51 }
52 if (count == 0) {
53 // this should be an implementation bug, not an operational error.
54 isc_throw(Unexpected, "Zone checker found an empty SOA RRset");
55 }
56 }
57 if (count != 1) {
58 callback.error("zone " + zoneText(zone_name, zone_class) + ": has " +
59 lexical_cast<string>(count) + " SOA records");
60 }
61}
62
63// Check if a target name is beyond zone cut, either due to delegation or
64// DNAME. Note that DNAME works on the origin but not on the name itself,
65// while delegation works on the name itself (but the NS at the origin is not
66// delegation).
67 ConstRRsetPtr
68findZoneCut(const Name& zone_name, const RRClass& zone_class,
69 const RRsetCollectionBase& zone_rrsets, const Name& target_name) {
70 const unsigned int origin_count = zone_name.getLabelCount();
71 const unsigned int target_count = target_name.getLabelCount();
72 assert(origin_count <= target_count);
73
74 for (unsigned int l = origin_count; l <= target_count; ++l) {
75 const Name& mid_name = (l == target_count) ? target_name :
76 target_name.split(target_count - l);
77
78 ConstRRsetPtr found;
79 if (l != origin_count &&
80 (found = zone_rrsets.find(mid_name, zone_class, RRType::NS())) !=
81 NULL) {
82 return (found);
83 }
84 if (l != target_count &&
85 (found = zone_rrsets.find(mid_name, zone_class, RRType::DNAME()))
86 != NULL) {
87 return (found);
88 }
89 }
90 return (ConstRRsetPtr());
91}
92
93// Check if each "in-zone" NS name has an address record, identifying some
94// error cases.
95void
96checkNSNames(const Name& zone_name, const RRClass& zone_class,
97 const RRsetCollectionBase& zone_rrsets,
98 ConstRRsetPtr ns_rrset, ZoneCheckerCallbacks& callbacks) {
99 if (ns_rrset->getRdataCount() == 0) {
100 // this should be an implementation bug, not an operational error.
101 isc_throw(Unexpected, "Zone checker found an empty NS RRset");
102 }
103
104 for (RdataIteratorPtr rit = ns_rrset->getRdataIterator();
105 !rit->isLast();
106 rit->next()) {
107 const rdata::generic::NS* ns_data =
108 dynamic_cast<const rdata::generic::NS*>(&rit->getCurrent());
109 if (ns_data == NULL) {
110 isc_throw(Unexpected, "Zone checker found bad RDATA in NS");
111 }
112 const Name& ns_name = ns_data->getNSName();
113 const NameComparisonResult::NameRelation reln =
114 ns_name.compare(zone_name).getRelation();
115 if (reln != NameComparisonResult::EQUAL &&
116 reln != NameComparisonResult::SUBDOMAIN) {
117 continue; // not in the zone. we can ignore it.
118 }
119
120 // Check if there's a zone cut between the origin and the NS name.
121 ConstRRsetPtr cut_rrset = findZoneCut(zone_name, zone_class,
122 zone_rrsets, ns_name);
123 if (cut_rrset) {
124 if (cut_rrset->getType() == RRType::NS()) {
125 continue; // delegation; making the NS name "out of zone".
126 } else if (cut_rrset->getType() == RRType::DNAME()) {
127 callbacks.error("zone " + zoneText(zone_name, zone_class) +
128 ": NS '" + ns_name.toText(true) + "' is " +
129 "below a DNAME '" +
130 cut_rrset->getName().toText(true) +
131 "' (illegal per RFC6672)");
132 continue;
133 } else {
134 assert(false);
135 }
136 }
137 if (zone_rrsets.find(ns_name, zone_class, RRType::CNAME()) != NULL) {
138 callbacks.error("zone " + zoneText(zone_name, zone_class) +
139 ": NS '" + ns_name.toText(true) + "' is a CNAME " +
140 "(illegal per RFC2181)");
141 continue;
142 }
143 if (zone_rrsets.find(ns_name, zone_class, RRType::A()) == NULL &&
144 zone_rrsets.find(ns_name, zone_class, RRType::AAAA()) == NULL) {
145 callbacks.warn("zone " + zoneText(zone_name, zone_class) +
146 ": NS has no address records (A or AAAA)");
147 }
148 }
149}
150
151void
152checkNS(const Name& zone_name, const RRClass& zone_class,
153 const RRsetCollectionBase& zone_rrsets,
154 ZoneCheckerCallbacks& callbacks) {
155 ConstRRsetPtr rrset =
156 zone_rrsets.find(zone_name, zone_class, RRType::NS());
157 if (rrset == NULL) {
158 callbacks.error("zone " + zoneText(zone_name, zone_class) +
159 ": has no NS records");
160 return;
161 }
162 checkNSNames(zone_name, zone_class, zone_rrsets, rrset, callbacks);
163}
164
165// The following is a simple wrapper of checker callback so checkZone()
166// can also remember any critical errors.
167void
168errorWrapper(const string& reason, const ZoneCheckerCallbacks* callbacks,
169 bool* had_error) {
170 *had_error = true;
171 callbacks->error(reason);
172}
173}
174
175bool
176checkZone(const Name& zone_name, const RRClass& zone_class,
177 const RRsetCollectionBase& zone_rrsets,
178 const ZoneCheckerCallbacks& callbacks) {
179 bool had_error = false;
180 ZoneCheckerCallbacks my_callbacks(
181 std::bind(errorWrapper, ph::_1, &callbacks, &had_error),
182 std::bind(&ZoneCheckerCallbacks::warn, &callbacks, ph::_1));
183
184 checkSOA(zone_name, zone_class, zone_rrsets, my_callbacks);
185 checkNS(zone_name, zone_class, zone_rrsets, my_callbacks);
186
187 return (!had_error);
188}
189
190} // end namespace dns
191} // end namespace isc
isc::dns::NameComparisonResult::NameRelation
NameRelation
The relation of two names under comparison.
Definition: name.h:142
isc::dns::NameComparisonResult::SUBDOMAIN
@ SUBDOMAIN
Definition: name.h:144
isc::dns::NameComparisonResult::EQUAL
@ EQUAL
Definition: name.h:145
isc::dns::Name
The Name class encapsulates DNS names.
Definition: name.h:223
isc::dns::RRClass
The RRClass class encapsulates DNS resource record classes.
Definition: rrclass.h:98
isc::dns::RRType::CNAME
static const RRType & CNAME()
Definition: rrtype.h:359
isc::dns::RRType::NS
static const RRType & NS()
Definition: rrtype.h:413
isc::dns::RRType::DNAME
static const RRType & DNAME()
Definition: rrtype.h:371
isc::dns::RRType::AAAA
static const RRType & AAAA()
Definition: rrtype.h:497
isc::dns::RRType::SOA
static const RRType & SOA()
Definition: rrtype.h:461
isc::dns::RRType::A
static const RRType & A()
Definition: rrtype.h:341
isc::dns::RRsetCollectionBase
Generic class to represent a set of RRsets.
Definition: rrset_collection_base.h:44
isc::dns::ZoneCheckerCallbacks
Set of callbacks used in zone checks.
Definition: zone_checker.h:21
isc::dns::ZoneCheckerCallbacks::warn
void warn(const std::string &reason) const
Call the callback for a non critical issue.
Definition: zone_checker.h:65
isc_throw
#define isc_throw(type, stream)
A shortcut macro to insert known values into exception arguments.
Definition: exceptions/exceptions.h:210
name.h
isc::dns::RdataIteratorPtr
boost::shared_ptr< RdataIterator > RdataIteratorPtr
A pointer-like type point to an RdataIterator object.
Definition: rrset.h:63
isc::dns::checkZone
bool checkZone(const Name &zone_name, const RRClass &zone_class, const RRsetCollectionBase &zone_rrsets, const ZoneCheckerCallbacks &callbacks)
Perform basic integrity checks on zone RRsets.
Definition: zone_checker.cc:176
isc::dns::ConstRRsetPtr
boost::shared_ptr< const AbstractRRset > ConstRRsetPtr
A pointer-like type pointing to an (immutable) RRset object.
Definition: rrset.h:60
isc
Defines the logger used by the top-level component of kea-lfc.
Definition: agent_parser.cc:143
rdataclass.h
rrclass.h
rrset.h
rrset_collection_base.h
rrtype.h
zone_checker.h