verity: add support for setting up verity-protected root disks in the initrd

This adds a generator and a small service that will look for "roothash="
on the kernel command line and use it for setting up a very partition
for the root device.

This provides similar functionality to nspawn's existing --roothash=
switch.

3 files changed, 211 insertions, 0 deletions

diff --git a/man/kernel-command-line.xml b/man/kernel-command-line.xml
index 7e1d408ded..415b8d3cf9 100644
--- a/man/kernel-command-line.xml
+++ b/man/kernel-command-line.xml
@@ -334,6 +334,19 @@
       </varlistentry>
 
       <varlistentry>
+        <term><varname>roothash=</varname></term>
+        <term><varname>systemd.verity=</varname></term>
+        <term><varname>rd.systemd.verity=</varname></term>
+        <term><varname>systemd.verity_root_data=</varname></term>
+        <term><varname>systemd.verity_root_hash=</varname></term>
+        <listitem>
+          <para>Configures the integrity protection root hash for the root file system, and other related
+          parameters. For details, see
+          <citerefentry><refentrytitle>systemd-veritysetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
+        </listitem>
+      </varlistentry>
+
+      <varlistentry>
         <term><varname>systemd.gpt_auto=</varname></term>
         <term><varname>rd.systemd.gpt_auto=</varname></term>
 
@@ -402,6 +415,7 @@
         <citerefentry><refentrytitle>systemd-udevd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
         <citerefentry project='die-net'><refentrytitle>plymouth</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
         <citerefentry><refentrytitle>systemd-cryptsetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+        <citerefentry><refentrytitle>systemd-veritysetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
         <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
         <citerefentry><refentrytitle>systemd-gpt-auto-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
         <citerefentry><refentrytitle>systemd-volatile-root.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
diff --git a/man/systemd-veritysetup-generator.xml b/man/systemd-veritysetup-generator.xml
new file mode 100644
index 0000000000..87d66e9ee5
--- /dev/null
+++ b/man/systemd-veritysetup-generator.xml
@@ -0,0 +1,122 @@
+<?xml version="1.0"?>
+<!--*-nxml-*-->
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
+<!--
+  This file is part of systemd.
+
+  Copyright 2016 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+-->
+<refentry id="systemd-veritysetup-generator" conditional='HAVE_LIBCRYPTSETUP'>
+
+  <refentryinfo>
+    <title>systemd-veritysetup-generator</title>
+    <productname>systemd</productname>
+
+    <authorgroup>
+      <author>
+        <contrib>Developer</contrib>
+        <firstname>Lennart</firstname>
+        <surname>Poettering</surname>
+        <email>lennart@poettering.net</email>
+      </author>
+    </authorgroup>
+  </refentryinfo>
+
+  <refmeta>
+    <refentrytitle>systemd-veritysetup-generator</refentrytitle>
+    <manvolnum>8</manvolnum>
+  </refmeta>
+
+  <refnamediv>
+    <refname>systemd-veritysetup-generator</refname>
+    <refpurpose>Unit generator for integrity protected block devices</refpurpose>
+  </refnamediv>
+
+  <refsynopsisdiv>
+    <para><filename>/usr/lib/systemd/system-generators/systemd-veritysetup-generator</filename></para>
+  </refsynopsisdiv>
+
+  <refsect1>
+    <title>Description</title>
+
+    <para><filename>systemd-veritysetup-generator</filename> is a generator that translates kernel command line options
+    configuring integrity protected block devices (verity) into native systemd units early at boot and when
+    configuration of the system manager is reloaded. This will create
+    <citerefentry><refentrytitle>systemd-veritysetup@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+    units as necessary.</para>
+
+    <para>Currently, only a single verity device may be se up with this generator, backing the root file system of the
+    OS.</para>
+
+    <para><filename>systemd-veritysetup-generator</filename> implements
+    <citerefentry><refentrytitle>systemd.generator</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
+  </refsect1>
+
+  <refsect1>
+    <title>Kernel Command Line</title>
+
+    <para><filename>systemd-veritysetup-generator</filename>
+    understands the following kernel command line parameters:</para>
+
+    <variablelist class='kernel-commandline-options'>
+      <varlistentry>
+        <term><varname>systemd.verity=</varname></term>
+        <term><varname>rd.systemd.verity=</varname></term>
+
+        <listitem><para>Takes a boolean argument. Defaults to <literal>yes</literal>. If <literal>no</literal>,
+        disables the generator entirely. <varname>rd.systemd.verity=</varname> is honored only by the initial RAM disk
+        (initrd) while <varname>systemd.verity=</varname> is honored by both the host system and the
+        initrd. </para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><varname>roothash=</varname></term>
+
+        <listitem><para>Takes a root hash value for the root file system. Expects a hash value formatted in hexadecimal
+        characters, of the appropriate length (i.e. most likely 256 bit/64 characters, or longer). If not specified via
+        <varname>systemd.verity_root_data=</varname> and <varname>systemd.verity_root_hash=</varname>, the hash and
+        data devices to use are automatically derived from the specified hash value. Specifically, the data partition
+        device is looked for under a GPT partition UUID derived from the first 128bit of the root hash, the hash
+        partition device is looked for under a GPT partition UUID derived from the last 128bit of the root hash. Hence
+        it is usually sufficient to specify the root hash to boot from an integrity protected root file system, as
+        device paths are automatically determined from it — as long as the partition table is properly set up.</para>
+        </listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><varname>systemd.verity_root_data=</varname></term>
+        <term><varname>systemd.verity_root_hash=</varname></term>
+
+        <listitem><para>These two settings take block device paths as arguments, and may be use to explicitly configure
+        the data partition and hash partition to use for setting up the integrity protection for the root file
+        system. If not specified, these paths are automatically derived from the <varname>roothash=</varname> argument
+        (see above).</para></listitem>
+      </varlistentry>
+
+    </variablelist>
+  </refsect1>
+
+  <refsect1>
+    <title>See Also</title>
+    <para>
+      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>systemd-veritysetup@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+      <citerefentry project='die-net'><refentrytitle>veritysetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+    </para>
+  </refsect1>
+
+</refentry>
diff --git a/man/systemd-veritysetup@.service.xml b/man/systemd-veritysetup@.service.xml
new file mode 100644
index 0000000000..173e5358e0
--- /dev/null
+++ b/man/systemd-veritysetup@.service.xml
@@ -0,0 +1,75 @@
+<?xml version="1.0"?>
+<!--*-nxml-*-->
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
+<!--
+  This file is part of systemd.
+
+  Copyright 2016 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+-->
+<refentry id="systemd-veritysetup@.service" conditional='HAVE_LIBCRYPTSETUP'>
+
+  <refentryinfo>
+    <title>systemd-veritysetup@.service</title>
+    <productname>systemd</productname>
+
+    <authorgroup>
+      <author>
+        <contrib>Developer</contrib>
+        <firstname>Lennart</firstname>
+        <surname>Poettering</surname>
+        <email>lennart@poettering.net</email>
+      </author>
+    </authorgroup>
+  </refentryinfo>
+
+  <refmeta>
+    <refentrytitle>systemd-veritysetup@.service</refentrytitle>
+    <manvolnum>8</manvolnum>
+  </refmeta>
+
+  <refnamediv>
+    <refname>systemd-veritysetup@.service</refname>
+    <refname>systemd-veritysetup</refname>
+    <refpurpose>Disk integrity protection logic</refpurpose>
+  </refnamediv>
+
+  <refsynopsisdiv>
+    <para><filename>systemd-veritysetup@.service</filename></para>
+    <para><filename>/usr/lib/systemd/systemd-veritysetup</filename></para>
+  </refsynopsisdiv>
+
+  <refsect1>
+    <title>Description</title>
+
+    <para><filename>systemd-veritysetup@.service</filename> is a service responsible for setting up integrity
+    protection (verity) block devices. It should be instantiated for each device that requires integrity
+    protection.</para>
+
+    <para>At early boot and when the system manager configuration is reloaded kernel command line configuration for
+    integrity protected block devices is translated into <filename>systemd-veritysetup@.service</filename> units by
+    <citerefentry><refentrytitle>systemd-veritysetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
+  </refsect1>
+
+  <refsect1>
+    <title>See Also</title>
+    <para>
+      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>systemd-veritysetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+      <citerefentry project='die-net'><refentrytitle>veritysetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+     </para>
+  </refsect1>
+
+</refentry>