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3c3a5ab35783f4d31cb5d3a15db9daadeb804daavboxsync - Copyright (C) 2004-2013 Internet Systems Consortium, Inc. ("ISC")
3c3a5ab35783f4d31cb5d3a15db9daadeb804daavboxsync - Copyright (C) 2000-2003 Internet Software Consortium.
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3c3a5ab35783f4d31cb5d3a15db9daadeb804daavboxsync - purpose with or without fee is hereby granted, provided that the above
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3c3a5ab35783f4d31cb5d3a15db9daadeb804daavboxsync - REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
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3c3a5ab35783f4d31cb5d3a15db9daadeb804daavboxsync<tr><th colspan="3" align="center"><span class="application">isc-hmac-fixup</span></th></tr>
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2f46a509fa35214396aedb4012d33b73fb4d6ec0vboxsync<p><span class="application">isc-hmac-fixup</span> — fixes HMAC keys generated by older versions of BIND</p>
2f46a509fa35214396aedb4012d33b73fb4d6ec0vboxsync<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>
54ae7b69a9aa4256e14122eaf595699d312cf901vboxsync Versions of BIND 9 up to and including BIND 9.6 had a bug causing
54ae7b69a9aa4256e14122eaf595699d312cf901vboxsync HMAC-SHA* TSIG keys which were longer than the digest length of the
d134558e26d3744503b2dbe50a75bcd3fa678432vboxsync hash algorithm (i.e., SHA1 keys longer than 160 bits, SHA256 keys
d134558e26d3744503b2dbe50a75bcd3fa678432vboxsync longer than 256 bits, etc) to be used incorrectly, generating a
2f46a509fa35214396aedb4012d33b73fb4d6ec0vboxsync message authentication code that was incompatible with other DNS
2f46a509fa35214396aedb4012d33b73fb4d6ec0vboxsync implementations.
2f46a509fa35214396aedb4012d33b73fb4d6ec0vboxsync This bug has been fixed in BIND 9.7. However, the fix may
2f46a509fa35214396aedb4012d33b73fb4d6ec0vboxsync cause incompatibility between older and newer versions of
ba5dd00fabaa3475fa5da200d134c73f1c961b49vboxsync BIND, when using long keys. <span><strong class="command">isc-hmac-fixup</strong></span>
ba5dd00fabaa3475fa5da200d134c73f1c961b49vboxsync modifies those keys to restore compatibility.
ba5dd00fabaa3475fa5da200d134c73f1c961b49vboxsync To modify a key, run <span><strong class="command">isc-hmac-fixup</strong></span> and
ba5dd00fabaa3475fa5da200d134c73f1c961b49vboxsync specify the key's algorithm and secret on the command line. If the
2f46a509fa35214396aedb4012d33b73fb4d6ec0vboxsync secret is longer than the digest length of the algorithm (64 bytes
2f46a509fa35214396aedb4012d33b73fb4d6ec0vboxsync for SHA1 through SHA256, or 128 bytes for SHA384 and SHA512), then a
2f46a509fa35214396aedb4012d33b73fb4d6ec0vboxsync new secret will be generated consisting of a hash digest of the old
ba5dd00fabaa3475fa5da200d134c73f1c961b49vboxsync secret. (If the secret did not require conversion, then it will be
ba5dd00fabaa3475fa5da200d134c73f1c961b49vboxsync printed without modification.)
ba5dd00fabaa3475fa5da200d134c73f1c961b49vboxsync<a name="id2659370"></a><h2>SECURITY CONSIDERATIONS</h2>
ba5dd00fabaa3475fa5da200d134c73f1c961b49vboxsync Secrets that have been converted by <span><strong class="command">isc-hmac-fixup</strong></span>
ba5dd00fabaa3475fa5da200d134c73f1c961b49vboxsync are shortened, but as this is how the HMAC protocol works in
ba5dd00fabaa3475fa5da200d134c73f1c961b49vboxsync operation anyway, it does not affect security. RFC 2104 notes,
ba5dd00fabaa3475fa5da200d134c73f1c961b49vboxsync "Keys longer than [the digest length] are acceptable but the
ba5dd00fabaa3475fa5da200d134c73f1c961b49vboxsync extra length would not significantly increase the function
ba5dd00fabaa3475fa5da200d134c73f1c961b49vboxsync <em class="citetitle">BIND 9 Administrator Reference Manual</em>,
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