1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
|
// Copyright (C) 2011-2015 Internet Systems Consortium, Inc. ("ISC")
//
// 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 http://mozilla.org/MPL/2.0/.
#include <exceptions/exceptions.h>
#include <dns/exceptions.h>
#include <dns/rdata.h>
#include <dns/rrtype.h>
#include <cassert>
#include <sstream>
#include <vector>
#include <cstring>
#include <stdint.h>
using namespace std;
namespace isc {
namespace dns {
namespace rdata {
namespace generic {
namespace detail {
namespace nsec {
void
checkRRTypeBitmaps(const char* const rrtype_name,
const vector<uint8_t>& typebits)
{
bool first = true;
unsigned int lastblock = 0;
const size_t total_len = typebits.size();
size_t i = 0;
while (i < total_len) {
if (i + 2 > total_len) {
isc_throw(DNSMessageFORMERR, rrtype_name <<
" RDATA from wire: incomplete bit map field");
}
const unsigned int block = typebits[i];
const size_t len = typebits[i + 1];
// Check that bitmap window blocks are in the correct order.
if (!first && block <= lastblock) {
isc_throw(DNSMessageFORMERR, rrtype_name <<
" RDATA from wire: Disordered window blocks found: "
<< lastblock << " then " << block);
}
// Check for legal length
if (len < 1 || len > 32) {
isc_throw(DNSMessageFORMERR, rrtype_name <<
" RDATA from wire: Invalid bitmap length: " << len);
}
// Check for overflow.
i += 2;
if (i + len > total_len) {
isc_throw(DNSMessageFORMERR, rrtype_name <<
" RDATA from wire: bitmap length too large: " << len);
}
// The last octet of the bitmap must be non zero.
if (typebits[i + len - 1] == 0) {
isc_throw(DNSMessageFORMERR, rrtype_name <<
" RDATA from wire: bitmap ending an all-zero byte");
}
i += len;
lastblock = block;
first = false;
}
}
void
buildBitmapsFromLexer(const char* const rrtype_name,
MasterLexer& lexer, vector<uint8_t>& typebits,
bool allow_empty)
{
uint8_t bitmap[8 * 1024]; // 64k bits
memset(bitmap, 0, sizeof(bitmap));
bool have_rrtypes = false;
std::string type_str;
while (true) {
const MasterToken& token =
lexer.getNextToken(MasterToken::STRING, true);
if ((token.getType() == MasterToken::END_OF_FILE) ||
(token.getType() == MasterToken::END_OF_LINE)) {
break;
}
// token is now assured to be of type STRING.
have_rrtypes = true;
token.getString(type_str);
try {
const int code = RRType(type_str).getCode();
bitmap[code / 8] |= (0x80 >> (code % 8));
} catch (const InvalidRRType&) {
isc_throw(InvalidRdataText, "Invalid RRtype in "
<< rrtype_name << " bitmap: " << type_str);
}
}
lexer.ungetToken();
if (!have_rrtypes) {
if (allow_empty) {
return;
}
isc_throw(InvalidRdataText,
rrtype_name <<
" record does not end with RR type mnemonic");
}
for (int window = 0; window < 256; ++window) {
int octet;
for (octet = 31; octet >= 0; octet--) {
if (bitmap[window * 32 + octet] != 0) {
break;
}
}
if (octet < 0) {
continue;
}
typebits.push_back(window);
typebits.push_back(octet + 1);
for (int i = 0; i <= octet; ++i) {
typebits.push_back(bitmap[window * 32 + i]);
}
}
}
void
bitmapsToText(const vector<uint8_t>& typebits, ostringstream& oss) {
// In the following loop we use string::at() rather than operator[].
// Since the index calculation is a bit complicated, it will be safer
// and easier to find a bug (if any). Note that this conversion method
// is generally not expected to be very efficient, so the slight overhead
// of at() should be acceptable.
const size_t typebits_len = typebits.size();
size_t len = 0;
for (size_t i = 0; i < typebits_len; i += len) {
assert(i + 2 <= typebits.size());
const unsigned int block = typebits.at(i);
len = typebits.at(i + 1);
assert(len > 0 && len <= 32);
i += 2;
for (size_t j = 0; j < len; ++j) {
if (typebits.at(i + j) == 0) {
continue;
}
for (size_t k = 0; k < 8; ++k) {
if ((typebits.at(i + j) & (0x80 >> k)) == 0) {
continue;
}
const unsigned int t = block * 256 + j * 8 + k;
assert(t < 65536);
oss << " " << RRType(t);
}
}
}
}
}
}
}
}
}
}
|
