mirror of
https://github.com/systemd/systemd.git
synced 2024-11-01 09:21:26 +03:00
175 lines
8.2 KiB
XML
175 lines
8.2 KiB
XML
<?xml version='1.0'?>
|
|
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
|
|
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
|
|
|
|
<!--
|
|
SPDX-License-Identifier: LGPL-2.1+
|
|
-->
|
|
|
|
<refentry id="dnssec-trust-anchors.d" conditional='ENABLE_RESOLVE'
|
|
xmlns:xi="http://www.w3.org/2001/XInclude">
|
|
<refentryinfo>
|
|
<title>dnssec-trust-anchors.d</title>
|
|
<productname>systemd</productname>
|
|
</refentryinfo>
|
|
|
|
<refmeta>
|
|
<refentrytitle>dnssec-trust-anchors.d</refentrytitle>
|
|
<manvolnum>5</manvolnum>
|
|
</refmeta>
|
|
|
|
<refnamediv>
|
|
<refname>dnssec-trust-anchors.d</refname>
|
|
<refname>systemd.positive</refname>
|
|
<refname>systemd.negative</refname>
|
|
<refpurpose>DNSSEC trust anchor configuration files</refpurpose>
|
|
</refnamediv>
|
|
|
|
<refsynopsisdiv>
|
|
<para><filename>/etc/dnssec-trust-anchors.d/*.positive</filename></para>
|
|
<para><filename>/run/dnssec-trust-anchors.d/*.positive</filename></para>
|
|
<para><filename>/usr/lib/dnssec-trust-anchors.d/*.positive</filename></para>
|
|
<para><filename>/etc/dnssec-trust-anchors.d/*.negative</filename></para>
|
|
<para><filename>/run/dnssec-trust-anchors.d/*.negative</filename></para>
|
|
<para><filename>/usr/lib/dnssec-trust-anchors.d/*.negative</filename></para>
|
|
</refsynopsisdiv>
|
|
|
|
<refsect1>
|
|
<title>Description</title>
|
|
|
|
<para>The DNSSEC trust anchor configuration files define positive
|
|
and negative trust anchors
|
|
<citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
|
|
bases DNSSEC integrity proofs on.</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Positive Trust Anchors</title>
|
|
|
|
<para>Positive trust anchor configuration files contain DNSKEY and
|
|
DS resource record definitions to use as base for DNSSEC integrity
|
|
proofs. See <ulink
|
|
url="https://tools.ietf.org/html/rfc4035#section-4.4">RFC 4035,
|
|
Section 4.4</ulink> for more information about DNSSEC trust
|
|
anchors.</para>
|
|
|
|
<para>Positive trust anchors are read from files with the suffix
|
|
<filename>.positive</filename> located in
|
|
<filename>/etc/dnssec-trust-anchors.d/</filename>,
|
|
<filename>/run/dnssec-trust-anchors.d/</filename> and
|
|
<filename>/usr/lib/dnssec-trust-anchors.d/</filename>. These
|
|
directories are searched in the specified order, and a trust
|
|
anchor file of the same name in an earlier path overrides a trust
|
|
anchor files in a later path. To disable a trust anchor file
|
|
shipped in <filename>/usr/lib/dnssec-trust-anchors.d/</filename>
|
|
it is sufficient to provide an identically-named file in
|
|
<filename>/etc/dnssec-trust-anchors.d/</filename> or
|
|
<filename>/run/dnssec-trust-anchors.d/</filename> that is either
|
|
empty or a symlink to <filename>/dev/null</filename> ("masked").</para>
|
|
|
|
<para>Positive trust anchor files are simple text files resembling
|
|
DNS zone files, as documented in <ulink
|
|
url="https://tools.ietf.org/html/rfc1035#section-5">RFC 1035, Section
|
|
5</ulink>. One DS or DNSKEY resource record may be listed per
|
|
line. Empty lines and lines starting with a semicolon
|
|
(<literal>;</literal>) are ignored and considered comments. A DS
|
|
resource record is specified like in the following example:</para>
|
|
|
|
<programlisting>. IN DS 19036 8 2 49aac11d7b6f6446702e54a1607371607a1a41855200fd2ce1cdde32f24e8fb5</programlisting>
|
|
|
|
<para>The first word specifies the domain, use
|
|
<literal>.</literal> for the root domain. The domain may be
|
|
specified with or without trailing dot, which is considered
|
|
equivalent. The second word must be <literal>IN</literal> the
|
|
third word <literal>DS</literal>. The following words specify the
|
|
key tag, signature algorithm, digest algorithm, followed by the
|
|
hex-encoded key fingerprint. See <ulink
|
|
url="https://tools.ietf.org/html/rfc4034#section-5">RFC 4034,
|
|
Section 5</ulink> for details about the precise syntax and meaning
|
|
of these fields.</para>
|
|
|
|
<para>Alternatively, DNSKEY resource records may be used to define
|
|
trust anchors, like in the following example:</para>
|
|
|
|
<programlisting>. IN DNSKEY 257 3 8 AwEAAagAIKlVZrpC6Ia7gEzahOR+9W29euxhJhVVLOyQbSEW0O8gcCjFFVQUTf6v58fLjwBd0YI0EzrAcQqBGCzh/RStIoO8g0NfnfL2MTJRkxoXbfDaUeVPQuYEhg37NZWAJQ9VnMVDxP/VHL496M/QZxkjf5/Efucp2gaDX6RS6CXpoY68LsvPVjR0ZSwzz1apAzvN9dlzEheX7ICJBBtuA6G3LQpzW5hOA2hzCTMjJPJ8LbqF6dsV6DoBQzgul0sGIcGOYl7OyQdXfZ57relSQageu+ipAdTTJ25AsRTAoub8ONGcLmqrAmRLKBP1dfwhYB4N7knNnulqQxA+Uk1ihz0=</programlisting>
|
|
|
|
<para>The first word specifies the domain again, the second word
|
|
must be <literal>IN</literal>, followed by
|
|
<literal>DNSKEY</literal>. The subsequent words encode the DNSKEY
|
|
flags, protocol and algorithm fields, followed by the key data
|
|
encoded in Base64. See <ulink
|
|
url="https://tools.ietf.org/html/rfc4034#section-2">RFC 4034,
|
|
Section 2</ulink> for details about the precise syntax and meaning
|
|
of these fields.</para>
|
|
|
|
<para>If multiple DS or DNSKEY records are defined for the same
|
|
domain (possibly even in different trust anchor files), all keys
|
|
are used and are considered equivalent as base for DNSSEC
|
|
proofs.</para>
|
|
|
|
<para>Note that <filename>systemd-resolved</filename> will
|
|
automatically use a built-in trust anchor key for the Internet
|
|
root domain if no positive trust anchors are defined for the root
|
|
domain. In most cases it is hence unnecessary to define an
|
|
explicit key with trust anchor files. The built-in key is disabled
|
|
as soon as at least one trust anchor key for the root domain is
|
|
defined in trust anchor files.</para>
|
|
|
|
<para>It is generally recommended to encode trust anchors in DS
|
|
resource records, rather than DNSKEY resource records.</para>
|
|
|
|
<para>If a trust anchor specified via a DS record is found revoked
|
|
it is automatically removed from the trust anchor database for the
|
|
runtime. See <ulink url="https://tools.ietf.org/html/rfc5011">RFC
|
|
5011</ulink> for details about revoked trust anchors. Note that
|
|
<filename>systemd-resolved</filename> will not update its trust
|
|
anchor database from DNS servers automatically. Instead, it is
|
|
recommended to update the resolver software or update the new
|
|
trust anchor via adding in new trust anchor files.</para>
|
|
|
|
<para>The current DNSSEC trust anchor for the Internet's root
|
|
domain is available at the <ulink
|
|
url="https://data.iana.org/root-anchors/root-anchors.xml">IANA
|
|
Trust Anchor and Keys</ulink> page.</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Negative Trust Anchors</title>
|
|
|
|
<para>Negative trust anchors define domains where DNSSEC validation shall be turned
|
|
off. Negative trust anchor files are found at the same location as positive trust anchor files,
|
|
and follow the same overriding rules. They are text files with the
|
|
<filename>.negative</filename> suffix. Empty lines and lines whose first character is
|
|
<literal>;</literal> are ignored. Each line specifies one domain name which is the root of a DNS
|
|
subtree where validation shall be disabled.</para>
|
|
|
|
<para>Negative trust anchors are useful to support private DNS
|
|
subtrees that are not referenced from the Internet DNS hierarchy,
|
|
and not signed.</para>
|
|
|
|
<para><ulink url="https://tools.ietf.org/html/rfc7646">RFC
|
|
7646</ulink> for details on negative trust anchors.</para>
|
|
|
|
<para>If no negative trust anchor files are configured a built-in
|
|
set of well-known private DNS zone domains is used as negative
|
|
trust anchors.</para>
|
|
|
|
<para>It is also possibly to define per-interface negative trust
|
|
anchors using the <varname>DNSSECNegativeTrustAnchors=</varname>
|
|
setting in
|
|
<citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>
|
|
files.</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>See Also</title>
|
|
<para>
|
|
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>resolved.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>
|
|
</para>
|
|
</refsect1>
|
|
|
|
</refentry>
|