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65ad89971ee9973074cd11c207af92bf5440df01Automatic Updater - Copyright (C) 2004-2010 Internet Systems Consortium, Inc. ("ISC")
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein - Copyright (C) 2000-2003 Internet Software Consortium.
689023771c563d8660e45d439a207e06e96de28fMark Andrews - Permission to use, copy, modify, and/or distribute this software for any
689023771c563d8660e45d439a207e06e96de28fMark Andrews - purpose with or without fee is hereby granted, provided that the above
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein - copyright notice and this permission notice appear in all copies.
689023771c563d8660e45d439a207e06e96de28fMark Andrews - THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein - REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
689023771c563d8660e45d439a207e06e96de28fMark Andrews - AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
689023771c563d8660e45d439a207e06e96de28fMark Andrews - INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
689023771c563d8660e45d439a207e06e96de28fMark Andrews - LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
689023771c563d8660e45d439a207e06e96de28fMark Andrews - OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
689023771c563d8660e45d439a207e06e96de28fMark Andrews - PERFORMANCE OF THIS SOFTWARE.
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60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<p><span class="application">isc-hmac-fixup</span> — fixes HMAC keys generated by older versions of BIND</p>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<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>
65ad89971ee9973074cd11c207af92bf5440df01Automatic Updater<a name="id2618256"></a><h2>DESCRIPTION</h2>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Versions of BIND 9 up to and including BIND 9.6 had a bug causing
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein HMAC-SHA* TSIG keys which were longer than the digest length of the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein hash algorithm (i.e., SHA1 keys longer than 160 bits, SHA256 keys
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein longer than 256 bits, etc) to be used incorrectly, generating a
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein message authentication code that was incompatible with other DNS
65ad89971ee9973074cd11c207af92bf5440df01Automatic Updater implementations.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein This bug has been fixed in BIND 9.7. However, the fix may
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein cause incompatibility between older and newer versions of
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein BIND, when using long keys. <span><strong class="command">isc-hmac-fixup</strong></span>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein modifies those keys to restore compatibility.
65ad89971ee9973074cd11c207af92bf5440df01Automatic Updater To modify a key, run <span><strong class="command">isc-hmac-fixup</strong></span> and
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein specify the key's algorithm and secret on the command line. If the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein secret is longer than the digest length of the algorithm (64 bytes
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein for SHA1 through SHA256, or 128 bytes for SHA384 and SHA512), then a
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein new secret will be generated consisting of a hash digest of the old
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein secret. (If the secret did not require conversion, then it will be
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein printed without modification.)
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<a name="id2618283"></a><h2>SECURITY CONSIDERATIONS</h2>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Secrets that have been converted by <span><strong class="command">isc-hmac-fixup</strong></span>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein are shortened, but as this is how the HMAC protocol works in
00124ad0406365d39f4b2d1011ef6a76706e9df0Mark Andrews operation anyway, it does not affect security. RFC 2104 notes,
3b4098640dd85040270f39b9a5ee5e22de99d3d6Mark Andrews "Keys longer than [the digest length] are acceptable but the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein extra length would not significantly increase the function
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <em class="citetitle">BIND 9 Administrator Reference Manual</em>,
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<p><span class="corpauthor">Internet Systems Consortium</span>
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