3 <!DOCTYPE refentry PUBLIC
"-//OASIS//DTD DocBook XML V4.5//EN"
4 "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd">
5 <!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
6 <refentry id=
"systemd-cryptenroll" xmlns:
xi=
"http://www.w3.org/2001/XInclude" conditional='HAVE_LIBCRYPTSETUP'
>
9 <title>systemd-cryptenroll
</title>
10 <productname>systemd
</productname>
14 <refentrytitle>systemd-cryptenroll
</refentrytitle>
15 <manvolnum>1</manvolnum>
19 <refname>systemd-cryptenroll
</refname>
20 <refpurpose>Enroll PKCS#
11, FIDO2, TPM2 token/devices to LUKS2 encrypted volumes
</refpurpose>
25 <command>systemd-cryptenroll
</command>
26 <arg choice=
"opt" rep=
"repeat">OPTIONS
</arg>
27 <arg choice=
"opt">DEVICE
</arg>
32 <title>Description
</title>
34 <para><command>systemd-cryptenroll
</command> is a tool for enrolling hardware security tokens and devices
35 into a LUKS2 encrypted volume, which may then be used to unlock the volume during boot. Specifically, it
36 supports tokens and credentials of the following kind to be enrolled:
</para>
39 <listitem><para>PKCS#
11 security tokens and smartcards that may carry an RSA or EC key pair (e.g.
40 various YubiKeys)
</para></listitem>
42 <listitem><para>FIDO2 security tokens that implement the
<literal>hmac-secret
</literal> extension (most
43 FIDO2 keys, including YubiKeys)
</para></listitem>
45 <listitem><para>TPM2 security devices
</para></listitem>
47 <listitem><para>Regular passphrases
</para></listitem>
49 <listitem><para>Recovery keys. These are similar to regular passphrases, however are randomly generated
50 on the computer and thus generally have higher entropy than user-chosen passphrases. Their character
51 set has been designed to ensure they are easy to type in, while having high entropy. They may also be
52 scanned off screen using QR codes. Recovery keys may be used for unlocking LUKS2 volumes wherever
53 passphrases are accepted. They are intended to be used in combination with an enrolled hardware
54 security token, as a recovery option when the token is lost.
</para></listitem>
57 <para>In addition, the tool may be used to enumerate currently enrolled security tokens and wipe a subset
58 of them. The latter may be combined with the enrollment operation of a new security token, in order to
59 update or replace enrollments.
</para>
61 <para>The tool supports only LUKS2 volumes, as it stores token meta-information in the LUKS2 JSON token
62 area, which is not available in other encryption formats.
</para>
65 <title>TPM2 PCRs and policies
</title>
67 <para>PCRs allow binding of the encryption of secrets to specific software versions and system state,
68 so that the enrolled key is only accessible (may be
"unsealed") if specific trusted software and/or
69 configuration is used. Such bindings may be created with the option
<option>--tpm2-pcrs=
</option>
70 described below.
</para>
72 <para>Secrets may also be bound indirectly: a signed policy for a state of some combination of PCR
73 values is provided, and the secret is bound to the public part of the key used to sign this policy.
74 This means that the owner of a key can generate a sequence of signed policies, for specific software
75 versions and system states, and the secret can be decrypted as long as the machine state matches one of
76 those policies. For example, a vendor may provide such a policy for each kernel+initrd update, allowing
77 users to encrypt secrets so that they can be decrypted when running any kernel+initrd signed by the
78 vendor. Such bindings may be created with the options
<option>--tpm2-public-key=
</option>,
79 <option>--tpm2-public-key-pcrs=
</option>,
<option>--tpm2-signature=
</option> described below.
82 <para>See
<ulink url=
"https://uapi-group.org/specifications/specs/linux_tpm_pcr_registry/">Linux TPM
83 PCR Registry
</ulink> for an authoritative list of PCRs and how they are updated. The table below
84 contains a quick reference, describing in particular the PCRs modified by systemd.
</para>
87 <title>Well-known PCR Definitions
</title>
89 <!-- See: https://trustedcomputinggroup.org/resource/pc-client-specific-platform-firmware-profile-specification/ -->
90 <!-- See: https://github.com/rhboot/shim/blob/main/README.tpm -->
91 <!-- See: https://www.gnu.org/software/grub/manual/grub/html_node/Measured-Boot.html -->
92 <!-- See: https://sourceforge.net/p/linux-ima/wiki/Home/ -->
93 <!-- See: https://github.com/tianocore-docs/edk2-TrustedBootChain/blob/main/4_Other_Trusted_Boot_Chains.md -->
94 <!-- See: https://wiki.archlinux.org/title/Trusted_Platform_Module#Accessing_PCR_registers -->
96 <tgroup cols='
3' align='left' colsep='
1' rowsep='
1'
>
97 <colspec colname=
"pcr" />
98 <colspec colname=
"name" />
99 <colspec colname=
"definition" />
105 <entry>Explanation
</entry>
112 <entry>platform-code
</entry>
113 <entry>Core system firmware executable code; changes on firmware updates
</entry>
118 <entry>platform-config
</entry>
119 <entry>Core system firmware data/host platform configuration; typically contains serial and model numbers, changes on basic hardware/CPU/RAM replacements
</entry>
124 <entry>external-code
</entry>
125 <entry>Extended or pluggable executable code; includes option ROMs on pluggable hardware
</entry>
130 <entry>external-config
</entry>
131 <entry>Extended or pluggable firmware data; includes information about pluggable hardware
</entry>
136 <entry>boot-loader-code
</entry>
137 <entry>Boot loader and additional drivers, PE binaries invoked by the boot loader; changes on boot loader updates.
<citerefentry><refentrytitle>sd-stub
</refentrytitle><manvolnum>7</manvolnum></citerefentry> measures system extension images read from the ESP here too (see
<citerefentry><refentrytitle>systemd-sysext
</refentrytitle><manvolnum>8</manvolnum></citerefentry>).
</entry>
142 <entry>boot-loader-config
</entry>
143 <entry>GPT/Partition table; changes when the partitions are added, modified, or removed
</entry>
148 <entry>secure-boot-policy
</entry>
149 <entry>Secure Boot state; changes when UEFI SecureBoot mode is enabled/disabled, or firmware certificates (PK, KEK, db, dbx, …) changes.
</entry>
154 <entry>kernel-initrd
</entry>
155 <entry>The Linux kernel measures all initrds it receives into this PCR.
</entry>
156 <!-- Strictly speaking only Linux >= 5.17 using the LOAD_FILE2 protocol, see https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f046fff8bc4c4d8f8a478022e76e40b818f692df -->
162 <entry>The IMA project measures its runtime state into this PCR.
</entry>
167 <entry>kernel-boot
</entry>
168 <entry><citerefentry><refentrytitle>systemd-stub
</refentrytitle><manvolnum>7</manvolnum></citerefentry> measures the ELF kernel image, embedded initrd and other payload of the PE image it is placed in into this PCR.
<citerefentry><refentrytitle>systemd-pcrphase.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry> measures boot phase strings into this PCR at various milestones of the boot process.
</entry>
173 <entry>kernel-config
</entry>
174 <entry><citerefentry><refentrytitle>systemd-boot
</refentrytitle><manvolnum>7</manvolnum></citerefentry> measures the kernel command line into this PCR.
<citerefentry><refentrytitle>systemd-stub
</refentrytitle><manvolnum>7</manvolnum></citerefentry> measures any manually specified kernel command line (i.e. a kernel command line that overrides the one embedded in the unified PE image) and loaded credentials into this PCR.
</entry>
179 <entry>sysexts
</entry>
180 <entry><citerefentry><refentrytitle>systemd-stub
</refentrytitle><manvolnum>7</manvolnum></citerefentry> measures any
<citerefentry><refentrytitle>systemd-sysext
</refentrytitle><manvolnum>8</manvolnum></citerefentry> images it passes to the booted kernel into this PCR.
</entry>
185 <entry>shim-policy
</entry>
186 <entry>The shim project measures its
"MOK" certificates and hashes into this PCR.
</entry>
191 <entry>system-identity
</entry>
192 <entry><citerefentry><refentrytitle>systemd-cryptsetup
</refentrytitle><manvolnum>8</manvolnum></citerefentry> optionally measures the volume key of activated LUKS volumes into this PCR.
<citerefentry><refentrytitle>systemd-pcrmachine.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry> measures the
<citerefentry><refentrytitle>machine-id
</refentrytitle><manvolnum>5</manvolnum></citerefentry> into this PCR.
<citerefentry><refentrytitle>systemd-pcrfs@.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry> measures mount points, file system UUIDs, labels, partition UUIDs of the root and
<filename>/var/
</filename> filesystems into this PCR.
</entry>
203 <entry>application-support
</entry>
204 <entry>Application Support
</entry>
210 <para>In general, encrypted volumes would be bound to some combination of PCRs
7,
11, and
14 (if
211 shim/MOK is used). In order to allow firmware and OS version updates, it is typically not advisable to
212 use PCRs such as
0 and
2, since the program code they cover should already be covered indirectly
213 through the certificates measured into PCR
7. Validation through certificates hashes is typically
214 preferable over validation through direct measurements as it is less brittle in context of OS/firmware
215 updates: the measurements will change on every update, but signatures should remain unchanged. See the
216 <ulink url=
"https://uapi-group.org/specifications/specs/linux_tpm_pcr_registry/">Linux TPM PCR
217 Registry
</ulink> for more discussion.
</para>
222 <title>Limitations
</title>
224 <para>Note that currently when enrolling a new key of one of the five supported types listed above, it is
225 required to first provide a passphrase, a recovery key or a FIDO2 token. It's currently not supported to
226 unlock a device with a TPM2/PKCS#
11 key in order to enroll a new TPM2/PKCS#
11 key. Thus, if in future key
227 roll-over is desired it's generally recommended to ensure a passphrase, a recovery key or a FIDO2 token
228 is always enrolled.
</para>
230 <para>Also note that support for enrolling multiple FIDO2 tokens is currently limited. When multiple FIDO2
231 tokens are enrolled,
<command>systemd-cryptseup
</command> will perform pre-flight requests to attempt to
232 identify which of the enrolled tokens are currently plugged in. However, this is not possible for FIDO2
233 tokens with user verification (UV, usually via biometrics), in which case it will fall back to attempting
234 each enrolled token one by one. This will result in multiple prompts for PIN and user verification. This
235 limitation does not apply to PKCS#
11 tokens.
</para>
239 <title>Compatibility
</title>
241 <para>Security technology both in systemd and in the general industry constantly evolves. In order to
242 provide best security guarantees, the way TPM2, FIDO2, PKCS#
11 devices are enrolled is regularly updated
243 in newer versions of systemd. Whenever this happens the following compatibility guarantees are given:
</para>
246 <listitem><para>Old enrollments continue to be supported and may be unlocked with newer versions of
247 <citerefentry><refentrytitle>systemd-cryptsetup@.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para></listitem>
249 <listitem><para>The opposite is not guaranteed however: it might not be possible to unlock volumes with
250 enrollments done with a newer version of
<command>systemd-cryptenroll
</command> with an older version
251 of
<command>systemd-cryptsetup
</command>.
</para></listitem>
254 <para>That said, it is generally recommended to use matching versions of
255 <command>systemd-cryptenroll
</command> and
<command>systemd-cryptsetup
</command>, since this is best
256 tested and supported.
</para>
258 <para>It might be advisable to re-enroll existing enrollments to take benefit of newer security features,
259 as they are added to systemd.
</para>
263 <title>Options
</title>
265 <para>The following options are understood:
</para>
269 <term><option>--password
</option></term>
271 <listitem><para>Enroll a regular password/passphrase. This command is mostly equivalent to
272 <command>cryptsetup luksAddKey
</command>, however may be combined with
273 <option>--wipe-slot=
</option> in one call, see below.
</para>
275 <xi:include href=
"version-info.xml" xpointer=
"v248"/></listitem>
279 <term><option>--recovery-key
</option></term>
281 <listitem><para>Enroll a recovery key. Recovery keys are mostly identical to passphrases, but are
282 computer-generated instead of being chosen by a human, and thus have a guaranteed high entropy. The
283 key uses a character set that is easy to type in, and may be scanned off screen via a QR code.
286 <xi:include href=
"version-info.xml" xpointer=
"v248"/></listitem>
290 <term><option>--unlock-key-file=
</option><replaceable>PATH
</replaceable></term>
292 <listitem><para>Use a file instead of a password/passphrase read from stdin to unlock the volume.
293 Expects the PATH to the file containing your key to unlock the volume. Currently there is nothing like
294 <option>--key-file-offset=
</option> or
<option>--key-file-size=
</option> so this file has to only
295 contain the full key.
</para>
297 <xi:include href=
"version-info.xml" xpointer=
"v252"/></listitem>
301 <term><option>--unlock-fido2-device=
</option><replaceable>PATH
</replaceable></term>
303 <listitem><para>Use a FIDO2 device instead of a password/passphrase read from stdin to unlock the
304 volume. Expects a
<filename>hidraw
</filename> device referring to the FIDO2 device (e.g.
305 <filename>/dev/hidraw1
</filename>). Alternatively the special value
<literal>auto
</literal> may be
306 specified, in order to automatically determine the device node of a currently plugged in security
307 token (of which there must be exactly one). This automatic discovery is unsupported if
308 <option>--fido2-device=
</option> option is also specified.
</para>
310 <xi:include href=
"version-info.xml" xpointer=
"v253"/></listitem>
314 <term><option>--pkcs11-token-uri=
</option><replaceable>URI
</replaceable></term>
316 <listitem><para>Enroll a PKCS#
11 security token or smartcard (e.g. a YubiKey). Expects a PKCS#
11
317 smartcard URI referring to the token. Alternatively the special value
<literal>auto
</literal> may
318 be specified, in order to automatically determine the URI of a currently plugged in security token
319 (of which there must be exactly one). The special value
<literal>list
</literal> may be used to
320 enumerate all suitable PKCS#
11 tokens currently plugged in.
</para>
322 <para>The PKCS#
11 token must contain an RSA or EC key pair which will be used to unlock a LUKS2 volume.
323 For RSA, a randomly generated volume key is encrypted with a public key in the token, and stored in
324 the LUKS2 JSON token header area. To unlock a volume, the stored encrypted volume key will be decrypted
325 with a private key in the token. For ECC, ECDH algorithm is used: we generate a pair of EC keys in
326 the same EC group, then derive a shared secret using the generated private key and the public key
327 in the token. The derived shared secret is used as a volume key. The generated public key is
328 stored in the LUKS2 JSON token header area. The generated private key is erased. To unlock a volume,
329 we derive the shared secret with the stored public key and a private key in the token.
</para>
331 <para>In order to unlock a LUKS2 volume with an enrolled PKCS#
11 security token, specify the
332 <option>pkcs11-uri=
</option> option in the respective
<filename>/etc/crypttab
</filename> line:
</para>
334 <programlisting>myvolume /dev/sda1 - pkcs11-uri=auto
</programlisting>
337 <citerefentry><refentrytitle>crypttab
</refentrytitle><manvolnum>5</manvolnum></citerefentry> for a
338 more comprehensive example of a
<command>systemd-cryptenroll
</command> invocation and its matching
339 <filename>/etc/crypttab
</filename> line.
</para>
341 <xi:include href=
"version-info.xml" xpointer=
"v248"/></listitem>
345 <term><option>--fido2-credential-algorithm=
</option><replaceable>STRING
</replaceable></term>
346 <listitem><para>Specify COSE algorithm used in credential generation. The default value is
347 <literal>es256
</literal>. Supported values are
<literal>es256
</literal>,
<literal>rs256
</literal>
348 and
<literal>eddsa
</literal>.
</para>
350 <para><literal>es256
</literal> denotes ECDSA over NIST P-
256 with SHA-
256.
<literal>rs256
</literal>
351 denotes
2048-bit RSA with PKCS#
1.5 padding and SHA-
256.
<literal>eddsa
</literal> denotes
352 EDDSA over Curve25519 with SHA-
512.
</para>
354 <para>Note that your authenticator may not support some algorithms.
</para>
356 <xi:include href=
"version-info.xml" xpointer=
"v251"/></listitem>
360 <term><option>--fido2-device=
</option><replaceable>PATH
</replaceable></term>
362 <listitem><para>Enroll a FIDO2 security token that implements the
<literal>hmac-secret
</literal>
363 extension (e.g. a YubiKey). Expects a
<filename>hidraw
</filename> device referring to the FIDO2
364 device (e.g.
<filename>/dev/hidraw1
</filename>). Alternatively the special value
365 <literal>auto
</literal> may be specified, in order to automatically determine the device node of a
366 currently plugged in security token (of which there must be exactly one). This automatic discovery
367 is unsupported if
<option>--unlock-fido2-device=
</option> option is also specified. The special value
368 <literal>list
</literal> may be used to enumerate all suitable FIDO2 tokens currently plugged in. Note
369 that many hardware security tokens that implement FIDO2 also implement the older PKCS#
11
370 standard. Typically FIDO2 is preferable, given it's simpler to use and more modern.
</para>
372 <para>In order to unlock a LUKS2 volume with an enrolled FIDO2 security token, specify the
373 <option>fido2-device=
</option> option in the respective
<filename>/etc/crypttab
</filename> line:
</para>
375 <programlisting>myvolume /dev/sda1 - fido2-device=auto
</programlisting>
378 <citerefentry><refentrytitle>crypttab
</refentrytitle><manvolnum>5</manvolnum></citerefentry> for a
379 more comprehensive example of a
<command>systemd-cryptenroll
</command> invocation and its matching
380 <filename>/etc/crypttab
</filename> line.
</para>
382 <xi:include href=
"version-info.xml" xpointer=
"v248"/></listitem>
386 <term><option>--fido2-with-client-pin=
</option><replaceable>BOOL
</replaceable></term>
388 <listitem><para>When enrolling a FIDO2 security token, controls whether to require the user to enter
389 a PIN when unlocking the volume (the FIDO2
<literal>clientPin
</literal> feature). Defaults to
390 <literal>yes
</literal>. (Note: this setting is without effect if the security token does not support
391 the
<literal>clientPin
</literal> feature at all, or does not allow enabling or disabling
394 <xi:include href=
"version-info.xml" xpointer=
"v249"/></listitem>
398 <term><option>--fido2-with-user-presence=
</option><replaceable>BOOL
</replaceable></term>
400 <listitem><para>When enrolling a FIDO2 security token, controls whether to require the user to
401 verify presence (tap the token, the FIDO2
<literal>up
</literal> feature) when unlocking the volume.
402 Defaults to
<literal>yes
</literal>. (Note: this setting is without effect if the security token does not support
403 the
<literal>up
</literal> feature at all, or does not allow enabling or disabling it.)
406 <xi:include href=
"version-info.xml" xpointer=
"v249"/></listitem>
410 <term><option>--fido2-with-user-verification=
</option><replaceable>BOOL
</replaceable></term>
412 <listitem><para>When enrolling a FIDO2 security token, controls whether to require user verification
413 when unlocking the volume (the FIDO2
<literal>uv
</literal> feature). Defaults to
414 <literal>no
</literal>. (Note: this setting is without effect if the security token does not support
415 the
<literal>uv
</literal> feature at all, or does not allow enabling or disabling it.)
</para>
417 <xi:include href=
"version-info.xml" xpointer=
"v249"/></listitem>
421 <term><option>--tpm2-device=
</option><replaceable>PATH
</replaceable></term>
423 <listitem><para>Enroll a TPM2 security chip. Expects a device node path referring to the TPM2 chip
424 (e.g.
<filename>/dev/tpmrm0
</filename>). Alternatively the special value
<literal>auto
</literal> may
425 be specified, in order to automatically determine the device node of a currently discovered TPM2
426 device (of which there must be exactly one). The special value
<literal>list
</literal> may be used to
427 enumerate all suitable TPM2 devices currently discovered.
</para>
429 <para>In order to unlock a LUKS2 volume with an enrolled TPM2 security chip, specify the
430 <option>tpm2-device=
</option> option in the respective
<filename>/etc/crypttab
</filename> line:
</para>
432 <programlisting>myvolume /dev/sda1 - tpm2-device=auto
</programlisting>
435 <citerefentry><refentrytitle>crypttab
</refentrytitle><manvolnum>5</manvolnum></citerefentry> for a
436 more comprehensive example of a
<command>systemd-cryptenroll
</command> invocation and its matching
437 <filename>/etc/crypttab
</filename> line.
</para>
439 <para>Use
<option>--tpm2-pcrs=
</option> (see below) to configure which TPM2 PCR indexes to bind the
440 enrollment to.
</para>
442 <xi:include href=
"version-info.xml" xpointer=
"v248"/></listitem>
446 <term><option>--tpm2-device-key=
</option><replaceable>PATH
</replaceable></term>
448 <listitem><para>Enroll a TPM2 security chip using its public key. Expects a path referring to the
449 TPM2 public key in TPM2B_PUBLIC format. This cannot be used with
<option>--tpm2-device=
</option>, as
450 it performs the same operation, but without connecting to the TPM2 security chip; instead the
451 enrollment is calculated using the provided TPM2 key. This is useful in situations where the TPM2
452 security chip is not available at the time of enrollment.
</para>
454 <para>The key, in most cases, should be the Storage Root Key (SRK) from a local TPM2 security
455 chip. If a key from a different handle (not the SRK) is used, you must specify its handle index using
456 <option>--tpm2-seal-key-handle=
</option>.
</para>
459 <citerefentry><refentrytitle>systemd-tpm2-setup.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
460 service writes the SRK to
<filename>/run/systemd/tpm2-srk-public-key.tpm2b_public
</filename>
461 automatically during boot, in the correct format.
</para>
463 <para>Alternatively, you may use
<command>systemd-analyze srk
</command> to retrieve the SRK from the
464 TPM2 security chip explicitly. See
465 <citerefentry><refentrytitle>systemd-analyze
</refentrytitle><manvolnum>1</manvolnum></citerefentry>
466 for details. Example:
</para>
468 <programlisting>systemd-analyze srk
> srk.tpm2b_public
</programlisting>
470 <xi:include href=
"version-info.xml" xpointer=
"v255"/></listitem>
474 <term><option>--tpm2-seal-key-handle=
</option><replaceable>HANDLE
</replaceable></term>
476 <listitem><para>Configures which parent key to use for sealing, using the TPM handle (index) of the
477 key. This is used to
"seal" (encrypt) a secret and must be used later to
"unseal" (decrypt) the
478 secret. Expects a hexadecimal
32bit integer, optionally prefixed with
479 <literal>0x
</literal>. Allowable values are any handle index in the persistent
480 (
<literal>0x81000000</literal>-
<literal>0x81ffffff</literal>) or transient
481 (
<literal>0x80000000</literal>-
<literal>0x80ffffff</literal>) ranges. Since transient handles are
482 lost after a TPM reset, and may be flushed during TPM context switching, they should not be used
483 except for very specific use cases, e.g. testing.
</para>
485 <para>The default is the Storage Root Key (SRK) handle index
<literal>0x81000001</literal>. A value
486 of
0 will use the default. For the SRK handle, a new key will be created and stored in the TPM if one
487 does not already exist; for any other handle, the key must already exist in the TPM at the specified
490 <para>This should not be changed unless you know what you are doing.
</para>
492 <xi:include href=
"version-info.xml" xpointer=
"v255"/></listitem>
496 <term><option>--tpm2-pcrs=
</option><arg rep=
"repeat">PCR
</arg></term>
498 <listitem><para>Configures the TPM2 PCRs (Platform Configuration Registers) to bind to when
499 enrollment is requested via
<option>--tpm2-device=
</option>. Takes a list of PCR entries, where each
500 entry starts with a name or numeric index in the range
0…
23, optionally followed by
501 <literal>:
</literal> and a hash algorithm name (specifying the PCR bank), optionally followed by
502 <literal>=
</literal> and a hash digest value. Multiple PCR entries are separated by
503 <literal>+
</literal>. If not specified, the default is to use PCR
7 only. If an empty string is
504 specified, binds the enrollment to no PCRs at all. See the table above for a list of available
507 <para>Example:
<option>--tpm2-pcrs=boot-loader-code+platform-config+boot-loader-config
</option>
508 specifies that PCR registers
4,
1, and
5 should be used.
</para>
509 <para>Example:
<option>--tpm2-pcrs=
7:sha256
</option> specifies that PCR register
7 from the SHA256
510 bank should be used.
</para>
511 <para>Example:
<option>--tpm2-pcrs=
4:sha1=
3a3f780f11a4b49969fcaa80cd6e3957c33b2275
</option>
512 specifies that PCR register
4 from the SHA1 bank should be used, and a hash digest value of
513 3a3f780f11a4b49969fcaa80cd6e3957c33b2275 will be used instead of reading the current PCR
516 <xi:include href=
"version-info.xml" xpointer=
"v248"/>
521 <term><option>--tpm2-with-pin=
</option><replaceable>BOOL
</replaceable></term>
523 <listitem><para>When enrolling a TPM2 device, controls whether to require the user to enter a PIN
524 when unlocking the volume in addition to PCR binding, based on TPM2 policy authentication. Defaults
525 to
<literal>no
</literal>. Despite being called PIN, any character can be used, not just numbers.
528 <para>Note that incorrect PIN entry when unlocking increments the TPM dictionary attack lockout
529 mechanism, and may lock out users for a prolonged time, depending on its configuration. The lockout
530 mechanism is a global property of the TPM,
<command>systemd-cryptenroll
</command> does not control or
531 configure the lockout mechanism. You may use tpm2-tss tools to inspect or configure the dictionary
532 attack lockout, with
<citerefentry
533 project='mankier'
><refentrytitle>tpm2_getcap
</refentrytitle><manvolnum>1</manvolnum></citerefentry>
535 project='mankier'
><refentrytitle>tpm2_dictionarylockout
</refentrytitle><manvolnum>1</manvolnum></citerefentry>
536 commands, respectively.
</para>
538 <xi:include href=
"version-info.xml" xpointer=
"v251"/></listitem>
542 <term><option>--tpm2-public-key=
</option><arg>PATH
</arg></term>
543 <term><option>--tpm2-public-key-pcrs=
</option><arg rep=
"repeat">PCR
</arg></term>
544 <term><option>--tpm2-signature=
</option><arg>PATH
</arg></term>
546 <listitem><para>Configures a TPM2 signed PCR policy to bind encryption to. The
547 <option>--tpm2-public-key=
</option> option accepts a path to a PEM encoded RSA public key, to bind
548 the encryption to. If this is not specified explicitly, but a file
549 <filename>tpm2-pcr-public-key.pem
</filename> exists in one of the directories
550 <filename>/etc/systemd/
</filename>,
<filename>/run/systemd/
</filename>,
551 <filename>/usr/lib/systemd/
</filename> (searched in this order), it is automatically used. The
552 <option>--tpm2-public-key-pcrs=
</option> option takes a list of TPM2 PCR indexes to bind to (same
553 syntax as
<option>--tpm2-pcrs=
</option> described above). If not specified defaults to
11 (i.e. this
554 binds the policy to any unified kernel image for which a PCR signature can be provided).
</para>
556 <para>Note the difference between
<option>--tpm2-pcrs=
</option> and
557 <option>--tpm2-public-key-pcrs=
</option>: the former binds decryption to the current, specific PCR
558 values; the latter binds decryption to any set of PCR values for which a signature by the specified
559 public key can be provided. The latter is hence more useful in scenarios where software updates shell
560 be possible without losing access to all previously encrypted LUKS2 volumes. Like with
561 <option>--tpm2-pcrs=
</option>, names defined in the table above can also be used to specify the
562 registers, for instance
563 <option>--tpm2-public-key-pcrs=boot-loader-code+system-identity
</option>.
</para>
565 <para>The
<option>--tpm2-signature=
</option> option takes a path to a TPM2 PCR signature file as
567 <citerefentry><refentrytitle>systemd-measure
</refentrytitle><manvolnum>1</manvolnum></citerefentry>
568 tool. If this is not specified explicitly, a suitable signature file
569 <filename>tpm2-pcr-signature.json
</filename> is searched for in
<filename>/etc/systemd/
</filename>,
570 <filename>/run/systemd/
</filename>,
<filename>/usr/lib/systemd/
</filename> (in this order) and used.
571 If a signature file is specified or found it is used to verify if the volume can be unlocked with it
572 given the current PCR state, before the new slot is written to disk. This is intended as safety net
573 to ensure that access to a volume is not lost if a public key is enrolled for which no valid
574 signature for the current PCR state is available. If the supplied signature does not unlock the
575 current PCR state and public key combination, no slot is enrolled and the operation will fail. If no
576 signature file is specified or found no such safety verification is done.
</para>
578 <xi:include href=
"version-info.xml" xpointer=
"v252"/></listitem>
582 <term><option>--tpm2-pcrlock=
</option><arg>PATH
</arg></term>
584 <listitem><para>Configures a TPM2 pcrlock policy to bind encryption to. Expects a path to a pcrlock
585 policy file as generated by the
586 <citerefentry><refentrytitle>systemd-pcrlock
</refentrytitle><manvolnum>1</manvolnum></citerefentry>
587 tool. If a TPM2 device is enrolled and this option is not used but a file
588 <filename>pcrlock.json
</filename> is found in
<filename>/run/systemd/
</filename> or
589 <filename>/var/lib/systemd/
</filename> it is automatically used. Assign an empty string to turn this
590 behaviour off.
</para>
592 <xi:include href=
"version-info.xml" xpointer=
"v255"/></listitem>
596 <term><option>--wipe-slot=
</option><arg rep=
"repeat">SLOT
</arg></term>
598 <listitem><para>Wipes one or more LUKS2 key slots. Takes a comma separated list of numeric slot
599 indexes, or the special strings
<literal>all
</literal> (for wiping all key slots),
600 <literal>empty
</literal> (for wiping all key slots that are unlocked by an empty passphrase),
601 <literal>password
</literal> (for wiping all key slots that are unlocked by a traditional passphrase),
602 <literal>recovery
</literal> (for wiping all key slots that are unlocked by a recovery key),
603 <literal>pkcs11
</literal> (for wiping all key slots that are unlocked by a PKCS#
11 token),
604 <literal>fido2
</literal> (for wiping all key slots that are unlocked by a FIDO2 token),
605 <literal>tpm2
</literal> (for wiping all key slots that are unlocked by a TPM2 chip), or any
606 combination of these strings or numeric indexes, in which case all slots matching either are
607 wiped. As safety precaution an operation that wipes all slots without exception (so that the volume
608 cannot be unlocked at all anymore, unless the volume key is known) is refused.
</para>
610 <para>This switch may be used alone, in which case only the requested wipe operation is executed. It
611 may also be used in combination with any of the enrollment options listed above, in which case the
612 enrollment is completed first, and only when successful the wipe operation executed — and the newly
613 added slot is always excluded from the wiping. Combining enrollment and slot wiping may thus be used to
614 update existing enrollments:
</para>
616 <programlisting>systemd-cryptenroll /dev/sda1 --wipe-slot=tpm2 --tpm2-device=auto
</programlisting>
618 <para>The above command will enroll the TPM2 chip, and then wipe all previously created TPM2
619 enrollments on the LUKS2 volume, leaving only the newly created one. Combining wiping and enrollment
620 may also be used to replace enrollments of different types, for example for changing from a PKCS#
11
621 enrollment to a FIDO2 one:
</para>
623 <programlisting>systemd-cryptenroll /dev/sda1 --wipe-slot=pkcs11 --fido2-device=auto
</programlisting>
625 <para>Or for replacing an enrolled empty password by TPM2:
</para>
627 <programlisting>systemd-cryptenroll /dev/sda1 --wipe-slot=empty --tpm2-device=auto
</programlisting>
629 <xi:include href=
"version-info.xml" xpointer=
"v248"/>
633 <xi:include href=
"standard-options.xml" xpointer=
"help" />
634 <xi:include href=
"standard-options.xml" xpointer=
"version" />
640 <title>Exit status
</title>
642 <para>On success,
0 is returned, a non-zero failure code otherwise.
</para>
646 <title>Examples
</title>
648 <para><citerefentry><refentrytitle>crypttab
</refentrytitle><manvolnum>5</manvolnum></citerefentry> and
649 <citerefentry><refentrytitle>systemd-measure
</refentrytitle><manvolnum>1</manvolnum></citerefentry>
650 contain various examples employing
<command>systemd-cryptenroll
</command>.
</para>
654 <title>See Also
</title>
655 <para><simplelist type=
"inline">
656 <member><citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
657 <member><citerefentry><refentrytitle>systemd-cryptsetup@.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
658 <member><citerefentry><refentrytitle>crypttab
</refentrytitle><manvolnum>5</manvolnum></citerefentry></member>
659 <member><citerefentry project='die-net'
><refentrytitle>cryptsetup
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
660 <member><citerefentry><refentrytitle>systemd-measure
</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>