systemd/man/systemd-pcrlock.xml

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<refentry id="systemd-pcrlock" conditional='ENABLE_BOOTLOADER HAVE_OPENSSL HAVE_TPM2'
          xmlns:xi="http://www.w3.org/2001/XInclude">

  <refentryinfo>
    <title>systemd-pcrlock</title>
    <productname>systemd</productname>
  </refentryinfo>

  <refmeta>
    <refentrytitle>systemd-pcrlock</refentrytitle>
    <manvolnum>8</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>systemd-pcrlock</refname>
    <refname>systemd-pcrlock-file-system.service</refname>
    <refname>systemd-pcrlock-firmware-code.service</refname>
    <refname>systemd-pcrlock-firmware-config.service</refname>
    <refname>systemd-pcrlock-machine-id.service</refname>
    <refname>systemd-pcrlock-make-policy.service</refname>
    <refname>systemd-pcrlock-secureboot-authority.service</refname>
    <refname>systemd-pcrlock-secureboot-policy.service</refname>
    <refpurpose>Analyze and predict TPM2 PCR states and generate an access policy from the prediction</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <cmdsynopsis>
      <command>/usr/lib/systemd/systemd-pcrlock</command> <arg choice="opt" rep="repeat">OPTIONS</arg>
    </cmdsynopsis>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para>Note: this command is experimental for now. While it is likely to become a regular component of
    systemd, it might still change in behaviour and interface.</para>

    <para><command>systemd-pcrlock</command> is a tool that may be used to analyze and predict TPM2 PCR
    measurements, and generate TPM2 access policies from the prediction which it stores in a TPM2 NV index
    (i.e. in the TPM2 non-volatile memory). This may then be used to restrict access to TPM2 objects (such as
    disk encryption keys) to system boot-ups in which only specific, trusted components are used.</para>

    <para><command>systemd-pcrlock</command> uses as input for its analysis and prediction:</para>

    <itemizedlist>
      <listitem><para>The UEFI firmware TPM2 event log
      (i.e. <filename>/sys/kernel/security/tpm0/binary_bios_measurements</filename>) of the current
      boot.</para></listitem>

      <listitem><para>The userspace TPM2 event log
      (i.e. <filename>/run/log/systemd/tpm2-measure.log</filename>) of the current
      boot.</para></listitem>

      <listitem><para>The current PCR state of the TPM2 chip.</para></listitem>

      <listitem><para>Boot component definition files (<filename>*.pcrlock</filename> and
      <filename>*.pcrlock.d/*.pcrlock</filename>, see
      <citerefentry><refentrytitle>systemd.pcrlock</refentrytitle><manvolnum>5</manvolnum></citerefentry>)
      that each define expected measurements for one component of the boot process, permitting alternative
      variants for each. (Variants may be used to bless multiple kernel versions or boot loader versions
      at the same time.)</para></listitem>
    </itemizedlist>

    <para>It uses these inputs to generate a combined event log, validating it against the PCR states. It
    then attempts to recognize event log records and matches them against the defined components. For each PCR
    where this can be done comprehensively (i.e. where all listed records and all defined components have
    been matched) this may then be used to predict future PCR measurements, taking the alternative variants
    defined for each component into account. This prediction may then be converted into a TPM2 access policy
    (consisting of TPM2 <function>PolicyPCR</function> and <function>PolicyOR</function> items), which is
    then stored in an NV index in the TPM2. This may be used to then lock secrets (such as disk encryption
    keys) to these policies (via a TPM2 <function>PolicyAuthorizeNV</function> policy).</para>

    <para>Use tools such as
    <citerefentry><refentrytitle>systemd-cryptenroll</refentrytitle><manvolnum>1</manvolnum></citerefentry>
    or <citerefentry><refentrytitle>systemd-repart</refentrytitle><manvolnum>8</manvolnum></citerefentry> to
    bind disk encryption to such a <command>systemd-pcrlock</command> TPM2 policy. Specifically, see the
    <option>--tpm2-pcrlock=</option> switches of these tools.</para>

    <para>The access policy logic requires a TPM2 device that implements the
    <literal>PolicyAuthorizeNV</literal> command, i.e. implements TPM 2.0 version 1.38 or newer.</para>
  </refsect1>

  <refsect1>
    <title>Commands</title>

    <para>The following commands are understood:</para>

    <variablelist>
      <varlistentry>
        <term><command>log</command></term>

        <listitem><para>This reads the combined TPM2 event log, validates it, matches it against the current
        PCR values, and outputs both in tabular form. Combine with <option>--json=</option> to generate
        output in JSON format.</para>

        <xi:include href="version-info.xml" xpointer="v255"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>cel</command></term>

        <listitem><para>This reads the combined TPM2 event log and writes it to STDOUT in <ulink
        url="https://trustedcomputinggroup.org/resource/canonical-event-log-format/">TCG Canonical Event Log
        Format (CEL-JSON)</ulink>.</para>

        <xi:include href="version-info.xml" xpointer="v255"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>list-components</command></term>

        <listitem><para>Shows a list of component definitions and their variants, i.e. the
        <filename>*.pcrlock</filename> files discovered in <filename>/var/lib/pcrlock.d/</filename>,
        <filename>/usr/lib/pcrlock.d/</filename>, and the other supported directories. See
        <citerefentry><refentrytitle>systemd.pcrlock</refentrytitle><manvolnum>5</manvolnum></citerefentry>
        for details on these files and the full list of directories searched.</para>

        <xi:include href="version-info.xml" xpointer="v255"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>predict</command></term>

        <listitem><para>Predicts the PCR state on future boots. This will analyze the TPM2 event log as
        described above, recognize components, and then generate all possible resulting PCR values for all
        combinations of component variants. Note that no prediction is made for PCRs whose value does not
        match the event log records, for which unrecognized measurements are discovered or for which
        components are defined that cannot be found in the event log. This is a safety measure to ensure that
        any generated access policy can be fulfilled correctly on current and future boots.</para>

        <xi:include href="version-info.xml" xpointer="v255"/>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><command>make-policy</command></term>

        <listitem><para>This predicts the PCR state for future boots, much like the
        <command>predict</command> command above. It then uses this data to generate a TPM2 access policy
        which it stores in a TPM2 NV index. The prediction and information about the used TPM2 and its NV
        index are written to <filename>/var/lib/systemd/pcrlock.json</filename>.</para>

        <para>The NV index is allocated on first invocation, and updated on subsequent invocations.</para>

        <para>The NV index contents may be changed (and thus the policy stored in it updated) by providing an
        access PIN. This PIN is normally generated automatically and stored in encrypted form (with an access
        policy binding it to the NV index itself) in the aforementioned JSON policy file. This PIN may be
        chosen by the user, via the <option>--recovery-pin=</option> switch. If specified it may be used as
        alternative path of access to update the policy.</para>

        <para>If the new prediction matches the old this command terminates quickly and executes no further
        operation. (Unless <option>--force</option> is specified, see below.)</para>

        <para>Starting with v256, a copy of the <filename>/var/lib/systemd/pcrlock.json</filename> policy
        file is encoded in a credential (see
        <citerefentry><refentrytitle>systemd-creds</refentrytitle><manvolnum>1</manvolnum></citerefentry> for
        details) and written to the EFI System Partition or XBOOTLDR partition, in the
        <filename>/loader/credentials/</filename> subdirectory. There it is picked up at boot by
        <citerefentry><refentrytitle>systemd-stub</refentrytitle><manvolnum>7</manvolnum></citerefentry> and
        passed to the invoked initrd, where it can be used to unlock the root file system (which typically
        contains <filename>/var/</filename>, which is where the primary copy of the policy is located, which
        hence cannot be used to unlock the root file system). The credential file is named after the boot
        entry token of the installation (see
        <citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>), which
        is configurable via the <option>--entry-token=</option> switch, see below.</para>

        <xi:include href="version-info.xml" xpointer="v255"/>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><command>remove-policy</command></term>

        <listitem><para>Removes a previously generated policy. Deletes the
        <filename>/var/lib/systemd/pcrlock.json</filename> file, and deallocates the NV index.</para>

        <xi:include href="version-info.xml" xpointer="v255"/>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><command>is-supported</command></term>

        <listitem><para>Checks if the local TPM2 supports all functionality for
        <command>systemd-pcrlock</command> to work correctly. This does similar tests as
        <command>systemd-analyze has-tpm2</command>, but also checks for supported of the TPM2 operations
        requires by <command>systemd-pcrlock</command>. Outputs one of <literal>no</literal>,
        <literal>partial</literal> (in case some parts of TPM2 support are available in hardware, firmware,
        OS, but not complete), <literal>obsolete</literal> (if TPM2 support is available in hardware,
        firmware and OS, but the operations required for <command>systemd-pcrlock</command> are missing),
        <literal>yes</literal>. Returns an exit status of zero if full support is available, otherwise
        non-zero.</para>

        <para>If combined with <option>--quiet</option>, suppresses the output of the string.</para>

        <para>Currently, this checks for support for the PolicAuthorizeNV TPM2 command, as well as for
        support of the SHA-256 hash algorithm.</para>

        <xi:include href="version-info.xml" xpointer="v258"/>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><command>lock-firmware-code</command></term>
        <term><command>unlock-firmware-code</command></term>

        <listitem><para>Generates/removes <filename>.pcrlock</filename> files based on the TPM2 event log of
        the current boot covering all records for PCRs 0 ("platform-code") and 2 ("external-code").</para>

        <para>This operation allows locking the boot process to the current version of the firmware of the
        system and its extension cards. This operation should only be used if the system vendor does not
        provide suitable pcrlock data ahead of time.</para>

        <para>Note that this data only matches the current version of the firmware. If a firmware update is
        applied this data will be out-of-date and any access policy generated from it will no longer pass. It
        is thus recommended to invoke <command>unlock-firmware-code</command> before doing a firmware update,
        followed by <command>make-policy</command> to refresh the policy.</para>

        <para><command>systemd-pcrlock lock-firmware-code</command> is invoked automatically at boot via the
        <filename>systemd-pcrlock-firmware-code.service</filename> unit, if enabled. This ensures that an
        access policy managed by <command>systemd-pcrlock</command> is automatically locked to the new
        firmware version whenever the policy has been relaxed temporarily, in order to cover for firmware
        updates, as described above.</para>

        <para>The files are only generated from the event log if the event log matches the current TPM2 PCR
        state.</para>

        <para>This writes/removes the files
        <filename>/var/lib/pcrlock.d/250-firmware-code-early.pcrlock.d/generated.pcrlock</filename> and
        <filename>/var/lib/pcrlock.d/550-firmware-code-late.pcrlock.d/generated.pcrlock</filename>.</para>

        <xi:include href="version-info.xml" xpointer="v255"/>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><command>lock-firmware-config</command></term>
        <term><command>unlock-firmware-config</command></term>

        <listitem><para>This is similar to
        <command>lock-firmware-code</command>/<command>unlock-firmware-code</command> but locks down the
        firmware configuration, i.e. PCRs 1 ("platform-config") and 3 ("external-config").</para>

        <para>This functionality should be used with care as in most scenarios a minor firmware configuration
        change should not invalidate access policies to TPM2 objects. Also note that some systems measure
        unstable and unpredictable information (e.g. current CPU voltages, temperatures, as part of SMBIOS
        data) to these PCRs, which means this form of lockdown cannot be used reliably on such systems. Use
        this functionality only if the system and hardware is well known and does not suffer by these
        limitations, for example in virtualized environments.</para>

        <para>Use <command>unlock-firmware-config</command> before making firmware configuration changes. If
        the <filename>systemd-pcrlock-firmware-config.service</filename> unit is enabled it will
        automatically generate a pcrlock file from the new measurements.</para>

        <para>This writes/removes the files
        <filename>/var/lib/pcrlock.d/250-firmware-config-early.pcrlock.d/generated.pcrlock</filename> and
        <filename>/var/lib/pcrlock.d/550-firmware-config-late.pcrlock.d/generated.pcrlock</filename>.</para>

        <xi:include href="version-info.xml" xpointer="v255"/>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><command>lock-secureboot-policy</command></term>
        <term><command>unlock-secureboot-policy</command></term>

        <listitem><para>Generates/removes a <filename>.pcrlock</filename> file based on the SecureBoot policy
        currently enforced. This looks at the SecureBoot, PK, KEK, db, dbx, dbt, dbr EFI variables and
        predicts their measurements to PCR 7 ("secure-boot-policy") on the next boot.</para>

        <para>Use <command>unlock-firmware-config</command> before applying SecureBoot policy updates. If
        the <filename>systemd-pcrlock-secureboot-policy.service</filename> unit is enabled it will
        automatically generate a pcrlock file from the policy discovered.</para>

        <para>This writes/removes the file
        <filename>/var/lib/pcrlock.d/230-secureboot-policy.pcrlock.d/generated.pcrlock</filename>.</para>

        <xi:include href="version-info.xml" xpointer="v255"/>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><command>lock-secureboot-authority</command></term>
        <term><command>unlock-secureboot-authority</command></term>

        <listitem><para>Generates/removes a <filename>.pcrlock</filename> file based on the SecureBoot
        authorities used to validate the boot path. SecureBoot authorities are the specific SecureBoot
        database entries that where used to validate the UEFI PE binaries executed at boot. This looks at the
        event log of the current boot, and uses relevant measurements on PCR 7
        ("secure-boot-policy").</para>

        <para>This writes/removes the file
        <filename>/var/lib/pcrlock.d/620-secureboot-authority.pcrlock.d/generated.pcrlock</filename>.</para>

        <xi:include href="version-info.xml" xpointer="v255"/>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><command>lock-gpt</command> <optional><replaceable>DEVICE</replaceable></optional></term>
        <term><command>unlock-gpt</command></term>

        <listitem><para>Generates/removes a <filename>.pcrlock</filename> file based on the GPT partition
        table of the specified disk. If no disk is specified automatically determines the block device
        backing the root file system. This locks the state of the disk partitioning of the booted medium,
        which firmware measures to PCR 5 ("boot-loader-config").</para>

        <para>This writes/removes the file
        <filename>/var/lib/pcrlock.d/600-gpt.pcrlock.d/generated.pcrlock</filename>.</para>

        <xi:include href="version-info.xml" xpointer="v255"/>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><command>lock-pe</command> <optional><replaceable>BINARY</replaceable></optional></term>
        <term><command>unlock-pe</command></term>

        <listitem><para>Generates/removes a <filename>.pcrlock</filename> file based on the specified PE
        binary. This is useful for predicting measurements the firmware makes to PCR 4 ("boot-loader-code")
        if the specified binary is part of the UEFI boot process. Use this on boot loader binaries and
        suchlike. Use <command>lock-uki</command> (see below) for PE binaries that are unified kernel images
        (UKIs).</para>

        <para>Expects a path to the PE binary as argument. If not specified, reads the binary from STDIN
        instead.</para>

        <para>The pcrlock file to write must be specified via the <option>--pcrlock=</option> switch.</para>

        <xi:include href="version-info.xml" xpointer="v255"/>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><command>lock-uki</command> <optional><replaceable>UKI</replaceable></optional></term>
        <term><command>unlock-uki</command></term>

        <listitem><para>Generates/removes a <filename>.pcrlock</filename> file based on the specified UKI PE
        binary. This is useful for predicting measurements the firmware makes to PCR 4 ("boot-loader-code"),
        and <citerefentry><refentrytitle>systemd-stub</refentrytitle><manvolnum>7</manvolnum></citerefentry>
        makes to PCR 11 ("kernel-boot"), if the specified UKI is booted. This is a superset of
        <command>lock-pe</command>.</para>

        <para>Expects a path to the UKI PE binary as argument. If not specified, reads the binary from STDIN
        instead.</para>

        <para>The pcrlock file to write must be specified via the <option>--pcrlock=</option> switch.</para>

        <xi:include href="version-info.xml" xpointer="v255"/>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><command>lock-machine-id</command></term>
        <term><command>unlock-machine-id</command></term>

        <listitem><para>Generates/removes a <filename>.pcrlock</filename> file based on
        <filename>/etc/machine-id</filename>. This is useful for predicting measurements
        <citerefentry><refentrytitle>systemd-pcrmachine.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
        makes to PCR 15 ("system-identity").</para>

        <para>This writes/removes the file
        <filename>/var/lib/pcrlock.d/820-machine-id.pcrlock</filename>.</para>

        <xi:include href="version-info.xml" xpointer="v255"/>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><command>lock-file-system</command> <optional><replaceable>PATH</replaceable></optional></term>
        <term><command>unlock-file-system</command> <optional><replaceable>PATH</replaceable></optional></term>

        <listitem><para>Generates/removes a <filename>.pcrlock</filename> file based on file system
        identity. This is useful for predicting measurements
        <citerefentry><refentrytitle>systemd-pcrfs@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
        makes to PCR 15 ("system-identity") for the root and <filename>/var/</filename> file systems.</para>

        <para>This writes/removes the files
        <filename>/var/lib/pcrlock.d/830-root-file-system.pcrlock</filename> and
        <filename>/var/lib/pcrlock.d/840-file-system-<replaceable>path</replaceable>.pcrlock</filename>.</para>

        <xi:include href="version-info.xml" xpointer="v255"/>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><command>lock-kernel-cmdline</command> <optional><replaceable>FILE</replaceable></optional></term>
        <term><command>unlock-kernel-cmdline</command></term>

        <listitem><para>Generates/removes a <filename>.pcrlock</filename> file based on
        <filename>/proc/cmdline</filename> (or the specified file if given). This is useful for predicting
        measurements the Linux kernel makes to PCR 9 ("kernel-initrd").</para>

        <para>This writes/removes the file
        <filename>/var/lib/pcrlock.d/710-kernel-cmdline.pcrlock/generated.pcrlock</filename>.</para>

        <xi:include href="version-info.xml" xpointer="v255"/>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><command>lock-kernel-initrd</command> <replaceable>FILE</replaceable></term>
        <term><command>unlock-kernel-initrd</command></term>

        <listitem><para>Generates/removes a <filename>.pcrlock</filename> file based on a kernel initrd cpio
        archive. This is useful for predicting measurements the Linux kernel makes to PCR 9
        ("kernel-initrd"). Do not use for
        <citerefentry><refentrytitle>systemd-stub</refentrytitle><manvolnum>7</manvolnum></citerefentry>
        UKIs, as the initrd is combined dynamically from various sources and hence does not take a single
        input, like this command.</para>

        <para>This writes/removes the file
        <filename>/var/lib/pcrlock.d/720-kernel-initrd.pcrlock/generated.pcrlock</filename>.</para>

        <xi:include href="version-info.xml" xpointer="v255"/>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><command>lock-raw</command> <optional><replaceable>FILE</replaceable></optional></term>
        <term><command>unlock-raw</command></term>

        <listitem><para>Generates/removes a <filename>.pcrlock</filename> file based on raw binary data. The
        data is either read from the specified file or from STDIN (if none is specified). This requires that
        <option>--pcrs=</option> is specified. The generated .pcrlock file is written to the file specified
        via <option>--pcrlock=</option> or to STDOUT (if none is specified).</para>

        <xi:include href="version-info.xml" xpointer="v255"/>
        </listitem>
      </varlistentry>

    </variablelist>
  </refsect1>

  <refsect1>
    <title>Options</title>

    <para>The following options are understood:</para>

    <variablelist>
      <varlistentry>
        <term><option>--raw-description</option></term>

        <listitem><para>When displaying the TPM2 event log do not attempt to decode the records to provide a
        friendly event log description string. Instead, show the binary payload data in escaped form.</para>

        <xi:include href="version-info.xml" xpointer="v255"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--pcr=</option></term>

        <listitem><para>Specifies the PCR number to use. May be specified more than once to select multiple
        PCRs.</para>

        <para>This is used by <command>lock-raw</command> and <command>lock-pe</command> to select the
        PCR to lock against.</para>

        <para>If used with <command>predict</command> and <command>make-policy</command> this will override
        which PCRs to include in the prediction and policy. If unspecified this defaults to PCRs 0-5, 7,
        11, 13-15. Note that these commands will not include any PCRs in the prediction/policy (even if specified
        explicitly) if there are measurements in the event log that do not match the current PCR value, or
        there are unrecognized measurements in the event log, or components define measurements not seen in
        the event log.</para>

        <xi:include href="version-info.xml" xpointer="v255"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--nv-index=</option></term>

        <listitem><para>Specifies the NV index to store the policy in. Honoured by
        <command>make-policy</command>. If not specified, the command will automatically pick a free NV
        index.</para>

        <xi:include href="version-info.xml" xpointer="v255"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--components=</option></term>

        <listitem><para>Takes a path to read <filename>*.pcrlock</filename> and
        <filename>*.pcrlock.d/*.pcrlock</filename> files from. May be used more than once to specify multiple
        such directories. If not specified, defaults to <filename>/etc/pcrlock.d/</filename>,
        <filename>/run/pcrlock.d/</filename>, <filename>/var/lib/pcrlock.d/</filename>,
        <filename>/usr/local/lib/pcrlock.d/</filename>, <filename>/usr/lib/pcrlock.d/</filename>.</para>

        <xi:include href="version-info.xml" xpointer="v255"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--location=</option></term>

        <listitem><para>Takes either a string or a colon-separated pair of strings. Configures up to which
        point in the sorted list of defined components to analyze/predict PCRs to. Typically, the
        <command>systemd-pcrlock</command> tool is invoked from a fully booted system after boot-up and
        before shutdown. This means various components that are defined for shutdown have not been measured
        yet, and should not be searched for. This option allows one to restrict which components are
        considered for analysis (taking only components before some point into account, ignoring components
        after them). The expected string is ordered against the filenames of the components defined. Any
        components with a lexicographically later name are ignored. This logic applies to the
        <command>log</command>, <command>predict</command>, and <command>make-policy</command> verbs. If a
        colon-separated pair of strings are specified then they select which phases of the boot to include
        in the prediction/policy. The first string defines where the first prediction shall be made, and the
        second string defines where the last prediction shall be made. All such predictions are then combined
        into one set.</para>

        <para>If used with <command>list-components</command> the selected location range will be highlighted
        in the component list.</para>

        <para>Defaults to <literal>760-:940-</literal>, which means the policies generated by default will
        basically cover the whole runtime of the OS userspace, from the initrd (as <literal>760-</literal>
        closely follows <filename>750-enter-initrd.pcrlock</filename>) until (and including) the main runtime
        of the system (as <literal>940-</literal> is closely followed by
        <filename>950-shutdown.pcrlock</filename>). See
        <citerefentry><refentrytitle>systemd.pcrlock</refentrytitle><manvolnum>5</manvolnum></citerefentry>
        for a full list of well-known components, that illustrate where this range is placed by
        default.</para>

        <xi:include href="version-info.xml" xpointer="v255"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--recovery-pin=</option></term>

        <listitem><para>Takes one of <literal>hide</literal>, <literal>show</literal> or
        <literal>query</literal>. Defaults to <literal>hide</literal>. Honoured by
        <command>make-policy</command>. If <literal>query</literal>, will query the user for a PIN to unlock
        the TPM2 NV index with. If no policy was created before, this PIN is used to protect the newly
        allocated NV index. If a policy has been created before, the PIN is used to unlock write access to
        the NV index. If either <literal>hide</literal> or <literal>show</literal> is used, a PIN is
        automatically generated, and — only in case of <literal>show</literal> — displayed on
        screen. Regardless if user supplied or automatically generated, it is stored in encrypted form in the
        policy metadata file. The recovery PIN may be used to regain write access to an NV index in case the
        access policy became out of date.</para>

        <xi:include href="version-info.xml" xpointer="v255"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--pcrlock=</option></term>

        <listitem><para>Takes a file system path as argument. If specified, configures where to write the
        generated pcrlock data to. Honoured by the various <command>lock-*</command> commands. If not
        specified, a default path is generally used, as documented above.</para>

        <xi:include href="version-info.xml" xpointer="v255"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--policy=</option></term>

        <listitem><para>Takes a file system path as argument. If specified, configures where to write pcrlock
        policy metadata to. If not specified, defaults to
        <filename>/var/lib/systemd/pcrlock.json</filename>.</para>

        <xi:include href="version-info.xml" xpointer="v255"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--force</option></term>

        <listitem><para>If specified with <command>make-policy</command>, the predicted policy will be
        written to the NV index even if it is detected to be the same as the previously stored
        one.</para>

        <xi:include href="version-info.xml" xpointer="v255"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--entry-token=</option></term>

        <listitem><para>Sets the boot entry token to use for the file name for the pcrlock policy credential
        in the EFI System Partition or XBOOTLDR partition. See the
        <citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> option of
        the same regarding expected values. This switch has an effect on the
        <command>make-policy</command> command only.</para>

        <xi:include href="version-info.xml" xpointer="v256"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--quiet</option></term>

        <listitem><para>If specified suppresses output when invoked for
        <command>is-supported</command>.</para>

        <xi:include href="version-info.xml" xpointer="v258"/></listitem>
      </varlistentry>

      <xi:include href="standard-options.xml" xpointer="json" />
      <xi:include href="standard-options.xml" xpointer="no-pager" />
      <xi:include href="standard-options.xml" xpointer="help" />
      <xi:include href="standard-options.xml" xpointer="version" />
    </variablelist>
  </refsect1>

  <refsect1>
    <title>Exit status</title>

    <para>On success, 0 is returned, a non-zero failure code otherwise.</para>
  </refsect1>

  <refsect1>
    <title>See Also</title>
    <para><simplelist type="inline">
      <member><citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
      <member><citerefentry><refentrytitle>systemd.pcrlock</refentrytitle><manvolnum>5</manvolnum></citerefentry></member>
      <member><citerefentry><refentrytitle>systemd-cryptenroll</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
      <member><citerefentry><refentrytitle>systemd-cryptsetup@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
      <member><citerefentry><refentrytitle>systemd-repart</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
      <member><citerefentry><refentrytitle>systemd-pcrmachine.service</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
      <member><citerefentry><refentrytitle>systemd-creds</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
      <member><citerefentry><refentrytitle>systemd-stub</refentrytitle><manvolnum>7</manvolnum></citerefentry></member>
      <member><citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
     </simplelist></para>
  </refsect1>

</refentry>