Adding upstream version 255.4.upstream/255.4

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 172 insertions, 0 deletions

diff --git a/man/dnssec-trust-anchors.d.xml b/man/dnssec-trust-anchors.d.xml
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+<?xml version='1.0'?>
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
+  "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
+<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
+
+<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 <constant class='dns'>DNSKEY</constant> and
+    <constant class='dns'>DS</constant> 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 <constant
+    class='dns'>DS</constant> or <constant class='dns'>DNSKEY</constant> resource record may be listed per
+    line. Empty lines and lines starting with <literal>#</literal> or <literal>;</literal> are ignored, which
+    may be used for commenting. A <constant class='dns'>DS</constant> 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, <constant class='dns'>DNSKEY</constant> 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 <constant class='dns'>DNSKEY</constant>
+    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 <constant class='dns'>DS</constant> or <constant class='dns'>DNSKEY</constant> 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 <constant class='dns'>DS</constant> resource
+    records, rather than <constant class='dns'>DNSKEY</constant> resource records.</para>
+
+    <para>If a trust anchor specified via a <constant class='dns'>DS</constant> 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. For example:</para>
+
+    <programlisting># Reverse IPv4 mappings
+10.in-addr.arpa
+16.172.in-addr.arpa
+168.192.in-addr.arpa
+...
+# Some custom domains
+prod
+stag
+</programlisting>
+
+    <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>