[Dnsmasq-discuss] Announce: dnsmasq-2.69
simon at thekelleys.org.uk
Wed Apr 9 20:13:33 UTC 2014
Dnsmasq-2.69 is here.
and (new) a signature
Many thanks to all who've contributed this major milestone. Most are
mentioned in the CHANGELOG, but it's also necessary to thank Evan Hunt,
Dave Taht, Giovanni Bajo and Comcast.
Release notes below.
Implement dynamic interface discovery on *BSD. This allows
the contructor: syntax to be used in dhcp-range for DHCPv6
on the BSD platform. Thanks to Matthias Andree for
valuable research on how to implement this.
Fix infinite loop associated with some --bogus-nxdomain
configs. Thanks fogobogo for the bug report.
Fix missing RA RDNS option with configuration like
--dhcp-option=option6:23,[::] Thanks to Tsachi Kimeldorfer
for spotting the problem.
Add [fd00::] and [fe80::] as special addresses in DHCPv6
options, analogous to [::]. [fd00::] is replaced with the
actual ULA of the interface on the machine running
dnsmasq, [fe80::] with the link-local address.
Thanks to Tsachi Kimeldorfer for championing this.
DNSSEC validation and caching. Dnsmasq needs to be
compiled with this enabled, with
make dnsmasq COPTS=-DHAVE_DNSSEC
this add dependencies on the nettle crypto library and the
gmp maths library. It's possible to have these linked
make dnsmasq COPTS='-DHAVE_DNSSEC -DHAVE_DNSSEC_STATIC'
which bloats the dnsmasq binary, but saves the size of
the shared libraries which are much bigger.
To enable, DNSSEC, you will need a set of
trust-anchors. Now that the TLDs are signed, this can be
the keys for the root zone, and for convenience they are
included in trust-anchors.conf in the dnsmasq
distribution. You should of course check that these are
legitimate and up-to-date. So, adding
to your config is all thats needed to get things
working. The upstream nameservers have to be DNSSEC-capable
too, of course. Many ISP nameservers aren't, but the
Google public nameservers (188.8.131.52 and 184.108.40.206) are.
When DNSSEC is configured, dnsmasq validates any queries
for domains which are signed. Query results which are
bogus are replaced with SERVFAIL replies, and results
which are correctly signed have the AD bit set. In
addition, and just as importantly, dnsmasq supplies
correct DNSSEC information to clients which are doing
their own validation, and caches DNSKEY, DS and RRSIG
records, which significantly improve the performance of
downstream validators. Setting --log-queries will show
DNSSEC in action.
If a domain is returned from an upstream nameserver without
DNSSEC signature, dnsmasq by default trusts this. This
means that for unsigned zone (still the majority) there
is effectively no cost for having DNSSEC enabled. Of course
this allows an attacker to replace a signed record with a
false unsigned record. This is addressed by the
--dnssec-check-unsigned flag, which instructs dnsmasq
to prove that an unsigned record is legitimate, by finding
a secure proof that the zone containing the record is not
signed. Doing this has costs (typically one or two extra
upstream queries). It also has a nasty failure mode if
dnsmasq's upstream nameservers are not DNSSEC capable.
Without --dnssec-check-unsigned using such an upstream
server will simply result in not queries being validated;
with --dnssec-check-unsigned enabled and a
DNSSEC-ignorant upstream server, _all_ queries will fail.
Note that DNSSEC requires that the local time is valid and
accurate, if not then DNSSEC validation will fail. NTP
should be running. This presents a problem for routers
without a battery-backed clock. To set the time needs NTP
to do DNS lookups, but lookups will fail until NTP has run.
To address this, there's a flag, --dnssec-no-timecheck
which disables the time checks (only) in DNSSEC. When
dnsmasq is started and the clock is not synced, this flag
should be used. As soon as the clock is synced, SIGHUP
dnsmasq. The SIGHUP clears the cache of partially-
validated data and resets the no-timecheck flag, so that
all DNSSEC checks henceforward will be complete.
The development of DNSSEC in dnsmasq was started by
Giovanni Bajo, to whom huge thanks are owed. It has been
supported by Comcast, whose techfund grant has allowed for
an invaluable period of full-time work to get it to
a workable state.
Add --rev-server. Thanks to Dave Taht for suggesting this.
Add --servers-file. Allows dynamic update of upstream
servers full access to configuration.
Add --local-service. Accept DNS queries only from hosts
whose address is on a local subnet, ie a subnet for which
an interface exists on the server. This option
only has effect if there are no --interface --except-
interface, --listen-address or --auth-server options. It is
intended to be set as a default on installation, to allow
unconfigured installations to be useful but also safe from
being used for DNS amplification attacks.
Fix crashes in cache_get_cname_target() when dangling CNAMEs
encountered. Thanks to Andy and the rt-n56u project for
find this and helping to chase it down.
Fix wrong RCODE in authoritative DNS replies to PTR
queries. The correct answer was included, but the RCODE was
set to NXDOMAIN. Thanks to Craig McQueen for spotting this.
Make statistics available as DNS queries in the .bind TLD
as well as logging them.
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