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
|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<!--
- Copyright (C) 2000-2019 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/.
-->
<html lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>isc-hmac-fixup</title>
<meta name="generator" content="DocBook XSL Stylesheets V1.78.1">
<link rel="home" href="Bv9ARM.html" title="BIND 9 Administrator Reference Manual">
<link rel="up" href="Bv9ARM.ch13.html" title="Manual pages">
<link rel="prev" href="man.genrandom.html" title="genrandom">
<link rel="next" href="man.nsec3hash.html" title="nsec3hash">
</head>
<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
<div class="navheader">
<table width="100%" summary="Navigation header">
<tr><th colspan="3" align="center"><span class="application">isc-hmac-fixup</span></th></tr>
<tr>
<td width="20%" align="left">
<a accesskey="p" href="man.genrandom.html">Prev</a>�</td>
<th width="60%" align="center">Manual pages</th>
<td width="20%" align="right">�<a accesskey="n" href="man.nsec3hash.html">Next</a>
</td>
</tr>
</table>
<hr>
</div>
<div class="refentry">
<a name="man.isc-hmac-fixup"></a><div class="titlepage"></div>
<div class="refnamediv">
<h2>Name</h2>
<p>
<span class="application">isc-hmac-fixup</span>
— fixes HMAC keys generated by older versions of BIND
</p>
</div>
<div class="refsynopsisdiv">
<h2>Synopsis</h2>
<div class="cmdsynopsis"><p>
<code class="command">isc-hmac-fixup</code>
{<em class="replaceable"><code>algorithm</code></em>}
{<em class="replaceable"><code>secret</code></em>}
</p></div>
</div>
<div class="refsection">
<a name="id-1.14.34.7"></a><h2>DESCRIPTION</h2>
<p>
Versions of BIND 9 up to and including BIND 9.6 had a bug causing
HMAC-SHA* TSIG keys which were longer than the digest length of the
hash algorithm (i.e., SHA1 keys longer than 160 bits, SHA256 keys
longer than 256 bits, etc) to be used incorrectly, generating a
message authentication code that was incompatible with other DNS
implementations.
</p>
<p>
This bug was fixed in BIND 9.7. However, the fix may
cause incompatibility between older and newer versions of
BIND, when using long keys. <span class="command"><strong>isc-hmac-fixup</strong></span>
modifies those keys to restore compatibility.
</p>
<p>
To modify a key, run <span class="command"><strong>isc-hmac-fixup</strong></span> and
specify the key's algorithm and secret on the command line. If the
secret is longer than the digest length of the algorithm (64 bytes
for SHA1 through SHA256, or 128 bytes for SHA384 and SHA512), then a
new secret will be generated consisting of a hash digest of the old
secret. (If the secret did not require conversion, then it will be
printed without modification.)
</p>
</div>
<div class="refsection">
<a name="id-1.14.34.8"></a><h2>SECURITY CONSIDERATIONS</h2>
<p>
Secrets that have been converted by <span class="command"><strong>isc-hmac-fixup</strong></span>
are shortened, but as this is how the HMAC protocol works in
operation anyway, it does not affect security. RFC 2104 notes,
"Keys longer than [the digest length] are acceptable but the
extra length would not significantly increase the function
strength."
</p>
</div>
<div class="refsection">
<a name="id-1.14.34.9"></a><h2>SEE ALSO</h2>
<p>
<em class="citetitle">BIND 9 Administrator Reference Manual</em>,
<em class="citetitle">RFC 2104</em>.
</p>
</div>
</div>
<div class="navfooter">
<hr>
<table width="100%" summary="Navigation footer">
<tr>
<td width="40%" align="left">
<a accesskey="p" href="man.genrandom.html">Prev</a>�</td>
<td width="20%" align="center"><a accesskey="u" href="Bv9ARM.ch13.html">Up</a></td>
<td width="40%" align="right">�<a accesskey="n" href="man.nsec3hash.html">Next</a>
</td>
</tr>
<tr>
<td width="40%" align="left" valign="top">
<span class="application">genrandom</span>�</td>
<td width="20%" align="center"><a accesskey="h" href="Bv9ARM.html">Home</a></td>
<td width="40%" align="right" valign="top">�<span class="application">nsec3hash</span>
</td>
</tr>
</table>
</div>
<p xmlns:db="http://docbook.org/ns/docbook" style="text-align: center;">BIND 9.11.5-P4 (Extended Support Version)</p>
</body>
</html>
|
