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author | Lennart Poettering <lennart@poettering.net> | 2020-12-07 17:18:52 +0100 |
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committer | Lennart Poettering <lennart@poettering.net> | 2020-12-17 20:02:32 +0100 |
commit | cf1e172d58b0c0fb3e09ba9b5e6c60093b5b896c (patch) | |
tree | 5c18a7fd9a5a26e7ca16b2b7d17698e8955ddae4 | |
parent | fido2: when listing fido2/hmac-secret devices, actually validate feature set (diff) | |
download | systemd-cf1e172d58b0c0fb3e09ba9b5e6c60093b5b896c.tar.xz systemd-cf1e172d58b0c0fb3e09ba9b5e6c60093b5b896c.zip |
man: document new features
-rw-r--r-- | man/crypttab.xml | 281 | ||||
-rw-r--r-- | man/fido2-crypttab.sh | 10 | ||||
-rw-r--r-- | man/repart.d.xml | 16 | ||||
-rw-r--r-- | man/rules/meson.build | 1 | ||||
-rw-r--r-- | man/systemd-cryptenroll.xml | 284 | ||||
-rw-r--r-- | man/systemd-cryptsetup-generator.xml | 1 | ||||
-rw-r--r-- | man/systemd-cryptsetup@.service.xml | 8 | ||||
-rw-r--r-- | man/systemd-repart.xml | 32 | ||||
-rw-r--r-- | man/tpm2-crypttab.sh | 10 | ||||
-rw-r--r-- | man/yubikey-crypttab.sh | 54 |
10 files changed, 603 insertions, 94 deletions
diff --git a/man/crypttab.xml b/man/crypttab.xml index 0c0f091025..2062a5b8e7 100644 --- a/man/crypttab.xml +++ b/man/crypttab.xml @@ -45,13 +45,12 @@ The first two fields are mandatory, the remaining two are optional.</para> - <para>Setting up encrypted block devices using this file supports - three encryption modes: LUKS, TrueCrypt and plain. See - <citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry> - for more information about each mode. When no mode is specified in - the options field and the block device contains a LUKS signature, - it is opened as a LUKS device; otherwise, it is assumed to be in - raw dm-crypt (plain mode) format.</para> + <para>Setting up encrypted block devices using this file supports four encryption modes: LUKS, TrueCrypt, + BitLocker and plain. See <citerefentry + project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry> for + more information about each mode. When no mode is specified in the options field and the block device + contains a LUKS signature, it is opened as a LUKS device; otherwise, it is assumed to be in raw dm-crypt + (plain mode) format.</para> <para>The four fields of <filename>/etc/crypttab</filename> are defined as follows:</para> @@ -65,9 +64,10 @@ <literal>UUID=</literal> followed by the UUID.</para></listitem> <listitem><para>The third field specifies an absolute path to a file with the encryption - key. Optionally, the path may be followed by <literal>:</literal> and an fstab device specification - (e.g. starting with <literal>LABEL=</literal> or similar); in which case the path is taken relative to - the device file system root. If the field is not present or is <literal>none</literal> or + key. Optionally, the path may be followed by <literal>:</literal> and an + <filename>/etc/fstab</filename> style device specification (e.g. starting with + <literal>LABEL=</literal> or similar); in which case the path is taken relative to the specified + device's file system root. If the field is not present or is <literal>none</literal> or <literal>-</literal>, a key file named after the volume to unlock (i.e. the first column of the line), suffixed with <filename>.key</filename> is automatically loaded from the <filename>/etc/cryptsetup-keys.d/</filename> and <filename>/run/cryptsetup-keys.d/</filename> @@ -83,6 +83,60 @@ <listitem><para>The fourth field, if present, is a comma-delimited list of options. The supported options are listed below.</para></listitem> </orderedlist> + </refsect1> + + <refsect1> + <title>Key Acquisition</title> + + <para>Six different mechanisms for acquiring the decryption key or passphrase unlocking the encrypted + volume are supported. Specifically:</para> + + <orderedlist> + + <listitem><para>Most prominently, the user may be queried interactively during volume activation + (i.e. typically at boot), asking them to type in the necessary passphrase(s).</para></listitem> + + <listitem><para>The (unencrypted) key may be read from a file on disk, possibly on removable media. The third field + of each line encodes the location, for details see above.</para></listitem> + + <listitem><para>The (unencrypted) key may be requested from another service, by specifying an + <constant>AF_UNIX</constant> file system socket in place of a key file in the third field. For details + see above and below.</para></listitem> + + <listitem><para>The key may be acquired via a PKCS#11 compatible hardware security token or + smartcard. In this case an encrypted key is stored on disk/removable media, acquired via + <constant>AF_UNIX</constant>, or stored in the LUKS2 JSON token metadata header. The encrypted key is + then decrypted by the PKCS#11 token with an RSA key stored on it, and then used to unlock the encrypted + volume. Use the <option>pkcs11-uri=</option> option described below to use this mechanism.</para></listitem> + + <listitem><para>Similar, the key may be acquired via a FIDO2 compatible hardware security token (which + must implement the "hmac-secret" extension). In this case a (during enrollment) randomly generated key + is stored on disk/removable media, acquired via <constant>AF_UNIX</constant>, or stored in the LUKS2 + JSON token metadata header. The random key is hashed via a keyed hash function (HMAC) on the FIDO2 + token, using a secret key stored on the token that never leaves it. The resulting hash value is then + used as key to unlock the encrypted volume. Use the <option>fido2-device=</option> option described + below to use this mechanism.</para></listitem> + + <listitem><para>Similar, the key may be acquired via a TPM2 security chip. In this case a (during + enrollment) randomly generated key — encrypted by an asymmetric key derived from the TPM2 chip's seed + key — is stored on disk/removable media, acquired via <constant>AF_UNIX</constant>, or stored in the + LUKS2 JSON token metadata header. Use the <option>tpm2-device=</option> option described below to use + this mechanism.</para></listitem> + </orderedlist> + + <para>For the latter five mechanisms the source for the key material used for unlocking the volume is + primarily configured in the third field of each <filename>/etc/crypttab</filename> line, but may also + configured in <filename>/etc/cryptsetup-keys.d/</filename> and + <filename>/run/cryptsetup-keys.d/</filename> (see above) or in the LUKS2 JSON token header (in case of + the latter three). Use the + <citerefentry><refentrytitle>systemd-cryptenroll</refentrytitle><manvolnum>1</manvolnum></citerefentry> + tool to enroll PKCS#11, FIDO2 and TPM2 devices in LUKS2 volumes.</para> + </refsect1> + + <refsect1> + <title>Supported Options</title> + + <para>The following options may be used in the fourth field of each line:</para> <variablelist class='fstab-options'> @@ -125,10 +179,10 @@ for possible values and the default value of this option.</para> - <para>Optionally, the path may be followed by <literal>:</literal> and an fstab device specification - (e.g. starting with <literal>UUID=</literal> or similar); in which case, the path is relative to the - device file system root. The device gets mounted automatically for LUKS device activation duration only. - </para></listitem> + <para>Optionally, the path may be followed by <literal>:</literal> and an + <filename>/etc/fstab</filename> device specification (e.g. starting with <literal>UUID=</literal> or + similar); in which case, the path is relative to the device file system root. The device gets mounted + automatically for LUKS device activation duration only.</para></listitem> </varlistentry> <varlistentry> @@ -198,8 +252,8 @@ <varlistentry> <term><option>bitlk</option></term> - <listitem><para>Decrypt Bitlocker drive. Encryption parameters - are deduced by cryptsetup from Bitlocker header.</para></listitem> + <listitem><para>Decrypt BitLocker drive. Encryption parameters + are deduced by cryptsetup from BitLocker header.</para></listitem> </varlistentry> <varlistentry> @@ -269,7 +323,7 @@ <varlistentry> <term><option>same-cpu-crypt</option></term> - <listitem><para>Perform encryption using the same cpu that IO was submitted on. The default is to use + <listitem><para>Perform encryption using the same CPU that IO was submitted on. The default is to use an unbound workqueue so that encryption work is automatically balanced between available CPUs.</para> <para>This requires kernel 4.0 or newer.</para> @@ -451,15 +505,134 @@ <varlistentry> <term><option>pkcs11-uri=</option></term> - <listitem><para>Takes a <ulink url="https://tools.ietf.org/html/rfc7512">RFC7512 PKCS#11 URI</ulink> - pointing to a private RSA key which is used to decrypt the key specified in the third column of the - line. This is useful for unlocking encrypted volumes through security tokens or smartcards. See below - for an example how to set up this mechanism for unlocking a LUKS volume with a YubiKey security - token. The specified URI can refer directly to a private RSA key stored on a token or alternatively + <listitem><para>Takes either the special value <literal>auto</literal> or an <ulink + url="https://tools.ietf.org/html/rfc7512">RFC7512 PKCS#11 URI</ulink> pointing to a private RSA key + which is used to decrypt the encrypted key specified in the third column of the line. This is useful + for unlocking encrypted volumes through PKCS#11 compatible security tokens or smartcards. See below + for an example how to set up this mechanism for unlocking a LUKS2 volume with a YubiKey security + token.</para> + + <para>If specified as <literal>auto</literal> the volume must be of type LUKS2 and must carry PKCS#11 + security token metadata in its LUKS2 JSON token section. In this mode the URI and the encrypted key + are automatically read from the LUKS2 JSON token header. Use + <citerefentry><refentrytitle>systemd-cryptenroll</refentrytitle><manvolnum>1</manvolnum></citerefentry> + as simple tool for enrolling PKCS#11 security tokens or smartcards in a way compatible with + <literal>auto</literal>. In this mode the third column of the line should remain empty (that is, + specified as <literal>-</literal>).</para> + + <para>The specified URI can refer directly to a private RSA key stored on a token or alternatively just to a slot or token, in which case a search for a suitable private RSA key will be performed. In - this case if multiple suitable objects are found the token is refused. The key configured in the - third column is passed as is to RSA decryption. The resulting decrypted key is then base64 encoded - before it is used to unlock the LUKS volume.</para></listitem> + this case if multiple suitable objects are found the token is refused. The encrypted key configured + in the third column of the line is passed as is (i.e. in binary form, unprocessed) to RSA + decryption. The resulting decrypted key is then Base64 encoded before it is used to unlock the LUKS + volume.</para> + + <para>Use <command>systemd-cryptenroll --pkcs11-token-uri=list</command> to list all suitable PKCS#11 + security tokens currently plugged in, along with their URIs.</para> + + <para>Note that many newer security tokens that may be used as PKCS#11 security token typically also + implement the newer and simpler FIDO2 standard. Consider using <option>fido2-device=</option> + (described below) to enroll it via FIDO2 instead. Note that a security token enrolled via PKCS#11 + cannot be used to unlock the volume via FIDO2, unless also enrolled via FIDO2, and vice + versa.</para></listitem> + </varlistentry> + + <varlistentry> + <term><option>fido2-device=</option></term> + + <listitem><para>Takes either the special value <literal>auto</literal> or the path to a + <literal>hidraw</literal> device node (e.g. <filename>/dev/hidraw1</filename>) referring to a FIDO2 + security token that implements the <literal>hmac-secret</literal> extension (most current hardware + security tokens do). See below for an example how to set up this mechanism for unlocking an encrypted + volume with a FIDO2 security token.</para> + + <para>If specified as <literal>auto</literal> the FIDO2 token device is automatically discovered, as + it is plugged in.</para> + + <para>FIDO2 volume unlocking requires a client ID hash (CID) to be configured via + <option>fido2-cid=</option> (see below) and a key to pass to the security token's HMAC functionality + (configured in the line's third column) to operate. If not configured and the volume is of type + LUKS2, the CID and the key are read from LUKS2 JSON token metadata instead. Use + <citerefentry><refentrytitle>systemd-cryptenroll</refentrytitle><manvolnum>1</manvolnum></citerefentry> + as simple tool for enrolling FIDO2 security tokens, compatible with this automatic mode, which is + only available for LUKS2 volumes.</para> + + <para>Use <command>systemd-cryptenroll --fido2-device=list</command> to list all suitable FIDO2 + security tokens currently plugged in, along with their device nodes.</para> + + <para>This option implements the following mechanism: the configured key is hashed via they HMAC + keyed hash function the FIDO2 device implements, keyed by a secret key embedded on the device. The + resulting hash value is Base64 encoded and used to unlock the LUKS2 volume. As it should not be + possible to extract the secret from the hardware token, it should not be possible to retrieve the + hashed key given the configured key — without possessing the hardware token.</para> + + <para>Note that many security tokens that implement FIDO2 also implement PKCS#11, suitable for + unlocking volumes via the <option>pkcs11-uri=</option> option described above. Typically the newer, + simpler FIDO2 standard is preferable.</para></listitem> + </varlistentry> + + <varlistentry> + <term><option>fido2-cid=</option></term> + + <listitem><para>Takes a Base64 encoded FIDO2 client ID to use for the FIDO2 unlock operation. If + specified, but <option>fido2-device=</option> is not, <option>fido2-device=auto</option> is + implied. If <option>fido2-device=</option> is used but <option>fido2-cid=</option> is not, the volume + must be of LUKS2 type, and the CID is read from the LUKS2 JSON token header. Use + <citerefentry><refentrytitle>systemd-cryptenroll</refentrytitle><manvolnum>1</manvolnum></citerefentry> + for enrolling a FIDO2 token in the LUKS2 header compatible with this automatic + mode.</para></listitem> + </varlistentry> + + <varlistentry> + <term><option>fido2-rp=</option></term> + + <listitem><para>Takes a string, configuring the FIDO2 Relying Party (rp) for the FIDO2 unlock + operation. If not specified <literal>io.systemd.cryptsetup</literal> is used, except if the the LUKS2 + JSON token header contains a different value. It should normally not be necessary to override + this.</para></listitem> + </varlistentry> + + <varlistentry> + <term><option>tpm2-device=</option></term> + + <listitem><para>Takes either the special value <literal>auto</literal> or the path to a device node + (e.g. <filename>/dev/tpmrm0</filename>) referring to a TPM2 security chip. See below for an example + how to set up this mechanism for unlocking an encrypted volume with a TPM2 chip.</para> + + <para>Use <option>tpm2-pcrs=</option> (see below) to configure the set of TPM2 PCRs to bind the + volume unlocking to. Use + <citerefentry><refentrytitle>systemd-cryptenroll</refentrytitle><manvolnum>1</manvolnum></citerefentry> + as simple tool for enrolling TPM2 security chips in LUKS2 volumes.</para> + + <para>If specified as <literal>auto</literal> the TPM2 device is automatically discovered. Use + <command>systemd-cryptenroll --tpm2-device=list</command> to list all suitable TPM2 devices currently + available, along with their device nodes.</para> + + <para>This option implements the following mechanism: when enrolling a TPM2 device via + <command>systemd-cryptenroll</command> on a LUKS2 volume, a randomized key unlocking the volume is + generated on the host and loaded into the TPM2 chip where it is encrypted with an asymmetric + "primary" key pair derived from the TPM2's internal "seed" key. Neither the seed key nor the primary + key are permitted to ever leave the TPM2 chip — however, the now encrypted randomized key may. It is + saved in the LUKS2 volume JSON token header. When unlocking the encrypted volume, the primary key + pair is generated on the TPM2 chip again (which works as long as the chip's seed key is correctly + maintained by the TPM2 chip), which is then used to decrypt (on the TPM2 chip) the encrypted key from + the LUKS2 volume JSON token header saved there during enrollment. The resulting decrypted key is then + used to unlock the volume. When the randomized key is encrypted the current values of the selected + PCRs (see below) are included in the operation, so that different PCR state results in different + encrypted keys and the decrypted key can only be recovered if the same PCR state is + reproduced.</para></listitem> + </varlistentry> + + <varlistentry> + <term><option>tpm2-pcrs=</option></term> + + <listitem><para>Takes a comma separated list of numeric TPM2 PCR (i.e. "Platform Configuration + Register") indexes to bind the TPM2 volume unlocking to. This option is only useful when TPM2 + enrollment metadata is not available in the LUKS2 JSON token header already, the way + <command>systemd-cryptenroll</command> writes it there. If not used (and no metadata in the LUKS2 + JSON token header defines it), defaults to a list of a single entry: PCR 7. Assign an empty string to + encode a policy that binds the key to no PCRs, making the key accessible to local programs regardless + of the current PCR state.</para></listitem> </varlistentry> <varlistentry> @@ -523,7 +696,7 @@ <programlisting><constant>NUL</constant> <replaceable>RANDOM</replaceable> <literal>/cryptsetup/</literal> <replaceable>VOLUME</replaceable></programlisting> <para>In other words: a <constant>NUL</constant> byte (as required for abstract namespace sockets), - followed by a random string (consisting of alphabenumeric characters only), followed by the literal + followed by a random string (consisting of alphanumeric characters only), followed by the literal string <literal>/cryptsetup/</literal>, followed by the name of the volume to acquire they key for. Example (for a volume <literal>myvol</literal>):</para> @@ -533,11 +706,13 @@ name with <citerefentry project='man-pages'><refentrytitle>getpeername</refentrytitle><manvolnum>2</manvolnum></citerefentry>, and use it to determine which key to send, allowing a single listening socket to serve keys for a - multitude of volumes. If the PKCS#11 logic is used (see below) the socket source name is picked in - identical fashion, except that the literal string <literal>/cryptsetup-pkcs11/</literal> is used. This is + multitude of volumes. If the PKCS#11 logic is used (see above) the socket source name is picked in + identical fashion, except that the literal string <literal>/cryptsetup-pkcs11/</literal> is used (similar + for FIDO2: <literal>/cryptsetup-fido2/</literal> and TPM2: <literal>/cryptsetup-tpm2/</literal>). This is done so that services providing key material know that not a secret key is requested but an encrypted key - that will be decrypted via the PKCS#11 logic to acquire the final secret key.</para> + that will be decrypted via the PKCS#11/FIDO2/TPM2 logic to acquire the final secret key.</para> </refsect1> + <refsect1> <title>Examples</title> <example> @@ -556,25 +731,48 @@ external /dev/sda3 keyfile:LABEL=keydev keyfile-timeout=10s,cipher=xchac </example> <example> - <title>Yubikey-based Volume Unlocking Example</title> + <title>Yubikey-based PKCS#11 Volume Unlocking Example</title> <para>The PKCS#11 logic allows hooking up any compatible security token that is capable of storing RSA - decryption keys. Here's an example how to set up a Yubikey security token for this purpose, using - <citerefentry project='debian'><refentrytitle>ykmap</refentrytitle><manvolnum>1</manvolnum></citerefentry> - from the yubikey-manager project:</para> + decryption keys for unlocking an encrypted volume. Here's an example how to set up a Yubikey security + token for this purpose on a LUKS2 volume, using <citerefentry + project='debian'><refentrytitle>ykmap</refentrytitle><manvolnum>1</manvolnum></citerefentry> from the + yubikey-manager project to initialize the token and + <citerefentry><refentrytitle>systemd-cryptenroll</refentrytitle><manvolnum>1</manvolnum></citerefentry> + to add it in the LUKS2 volume:</para> <programlisting><xi:include href="yubikey-crypttab.sh" parse="text" /></programlisting> -<para>A few notes on the above:</para> + <para>A few notes on the above:</para> + + <itemizedlist> + <listitem><para>We use RSA2048, which is the longest key size current Yubikeys support</para></listitem> + <listitem><para>We use Yubikey key slot 9d, since that's apparently the keyslot to use for decryption purposes, + <ulink url="https://developers.yubico.com/PIV/Introduction/Certificate_slots.html">see + documentation</ulink>.</para></listitem> + </itemizedlist> + </example> + + <example> + <title>FIDO2 Volume Unlocking Example</title> + + <para>The FIDO2 logic allows using any compatible FIDO2 security token that implements the + <literal>hmac-secret</literal> extension for unlocking an encrypted volume. Here's an example how to + set up a FIDO2 security token for this purpose for a LUKS2 volume, using + <citerefentry><refentrytitle>systemd-cryptenroll</refentrytitle><manvolnum>1</manvolnum></citerefentry>:</para> + +<programlisting><xi:include href="fido2-crypttab.sh" parse="text" /></programlisting> + </example> + + <example> + <title>TPM2 Volume Unlocking Example</title> -<itemizedlist> - <listitem><para>We use RSA2048, which is the longest key size current Yubikeys support</para></listitem> - <listitem><para>LUKS key size must be shorter than 2048bit due to RSA padding, hence we use 128 bytes</para></listitem> - <listitem><para>We use Yubikey key slot 9d, since that's apparently the keyslot to use for decryption purposes, - <ulink url="https://developers.yubico.com/PIV/Introduction/Certificate_slots.html">see - documentation</ulink>.</para></listitem> -</itemizedlist> + <para>The TPM2 logic allows using any TPM2 chip supported by the Linux kernel for unlocking an + encrypted volume. Here's an example how to set up a TPM2 chip for this purpose for a LUKS2 volume, + using + <citerefentry><refentrytitle>systemd-cryptenroll</refentrytitle><manvolnum>1</manvolnum></citerefentry>:</para> +<programlisting><xi:include href="tpm2-crypttab.sh" parse="text" /></programlisting> </example> </refsect1> @@ -584,6 +782,7 @@ external /dev/sda3 keyfile:LABEL=keydev keyfile-timeout=10s,cipher=xchac <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, <citerefentry><refentrytitle>systemd-cryptsetup@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, <citerefentry><refentrytitle>systemd-cryptsetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd-cryptenroll</refentrytitle><manvolnum>1</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>, <citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>mkswap</refentrytitle><manvolnum>8</manvolnum></citerefentry>, diff --git a/man/fido2-crypttab.sh b/man/fido2-crypttab.sh new file mode 100644 index 0000000000..49e536cae8 --- /dev/null +++ b/man/fido2-crypttab.sh @@ -0,0 +1,10 @@ +# Enroll the security token in the LUKS2 volume. Replace /dev/sdXn by the +# partition to use (e.g. /dev/sda1). +sudo systemd-cryptenroll --fido2-device=auto /dev/sdXn + +# Test: Let's run systemd-cryptsetup to test if this worked. +sudo /usr/lib/systemd/systemd-cryptsetup attach mytest /dev/sdXn - fido2-device=auto + +# If that worked, let's now add the same line persistently to /etc/crypttab, +# for the future. +sudo bash -c 'echo "mytest /dev/sdXn - fido2-device=auto" >> /etc/crypttab' diff --git a/man/repart.d.xml b/man/repart.d.xml index 6e31843a08..66debd336f 100644 --- a/man/repart.d.xml +++ b/man/repart.d.xml @@ -492,12 +492,19 @@ <varlistentry> <term><varname>Encrypt=</varname></term> - <listitem><para>Takes a boolean parameter, defaulting to false. If true the partition will be + <listitem><para>Takes one of <literal>off</literal>, <literal>key-file</literal>, + <literal>tpm2</literal> and <literal>key-file+tpm2</literal> (alternatively, also accepts a boolean + value, which is mapped to <literal>off</literal> when false, and <literal>key-file</literal> when + true). Defaults to <literal>off</literal>. If not <literal>off</literal> the partition will be formatted with a LUKS2 superblock, before the blocks configured with <varname>CopyBlocks=</varname> are copied in or the file system configured with <varname>Format=</varname> is created.</para> - <para>The LUKS2 UUID is automatically derived from the partition UUID in a stable fashion. A single - key is added to the LUKS2 superblock, configurable with the <option>--key-file=</option> switch to + <para>The LUKS2 UUID is automatically derived from the partition UUID in a stable fashion. If + <literal>key-file</literal> or <literal>key-file+tpm2</literal> is used a key is added to the LUKS2 + superblock, configurable with the <option>--key-file=</option> switch to + <command>systemd-repart</command>. If <literal>tpm2</literal> or <literal>key-file+tpm2</literal> is + used a key is added to the LUKS2 superblock that is enrolled to the local TPM2 chip, as configured + with the <option>--tpm2-device=</option> and <option>--tpm2-pcrs=</option> options to <command>systemd-repart</command>.</para> <para>When used this slightly alters the size allocation logic as the implicit, minimal size limits @@ -627,7 +634,8 @@ SizeMaxBytes=64M <para> <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, <citerefentry><refentrytitle>systemd-repart</refentrytitle><manvolnum>8</manvolnum></citerefentry>, - <citerefentry project='man-pages'><refentrytitle>sfdisk</refentrytitle><manvolnum>8</manvolnum></citerefentry> + <citerefentry project='man-pages'><refentrytitle>sfdisk</refentrytitle><manvolnum>8</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd-cryptenroll</refentrytitle><manvolnum>1</manvolnum></citerefentry> </para> </refsect1> diff --git a/man/rules/meson.build b/man/rules/meson.build index 97136fe758..cada4305a7 100644 --- a/man/rules/meson.build +++ b/man/rules/meson.build @@ -825,6 +825,7 @@ manpages = [ '8', ['systemd-coredump.socket', 'systemd-coredump@.service'], 'ENABLE_COREDUMP'], + ['systemd-cryptenroll', '1', [], 'HAVE_LIBCRYPTSETUP'], ['systemd-cryptsetup-generator', '8', [], 'HAVE_LIBCRYPTSETUP'], ['systemd-cryptsetup@.service', '8', diff --git a/man/systemd-cryptenroll.xml b/man/systemd-cryptenroll.xml new file mode 100644 index 0000000000..17a546b256 --- /dev/null +++ b/man/systemd-cryptenroll.xml @@ -0,0 +1,284 @@ +<?xml version="1.0"?> +<!--*-nxml-*--> +<!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="systemd-cryptenroll" xmlns:xi="http://www.w3.org/2001/XInclude" conditional='HAVE_LIBCRYPTSETUP'> + + <refentryinfo> + <title>systemd-cryptenroll</title> + <productname>systemd</productname> + </refentryinfo> + + <refmeta> + <refentrytitle>systemd-cryptenroll</refentrytitle> + <manvolnum>1</manvolnum> + </refmeta> + + <refnamediv> + <refname>systemd-cryptenroll</refname> + <refpurpose>Enroll PKCS#11, FIDO2, TPM2 token/devices to LUKS2 encrypted volumes</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <cmdsynopsis> + <command>systemd-cryptenroll <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="opt">DEVICE</arg></command> + </cmdsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para><command>systemd-cryptenroll</command> is a tool for enrolling hardware security tokens and devices into a + LUKS2 encrypted volume, which may then be used to unlock the volume during boot. Specifically, it supports + tokens and credentials of the following kind to be enrolled:</para> + + <orderedlist> + <listitem><para>PKCS#11 security tokens and smartcards that may carry an RSA key pair (e.g. various YubiKeys)</para></listitem> + + <listitem><para>FIDO2 security tokens that implement the <literal>hmac-secret</literal> extension (most FIDO2 keys, including YubiKeys)</para></listitem> + + <listitem><para>TPM2 security devices</para></listitem> + + <listitem><para>Recovery keys. These are similar to regular passphrases, however are randomly generated + on the computer and thus generally have higher entropy than user chosen passphrases. Their character + set has been designed to ensure they are easy to type in, while having high entropy. They may also be + scanned off screen using QR codes. Recovery keys may be used for unlocking LUKS2 volumes wherever + passphrases are accepted. They are intended to be used in combination with an enrolled hardware + security token, as a recovery option when the token is lost.</para></listitem> + + <listitem><para>Regular passphrases</para></listitem> + </orderedlist> + + <para>In addition, the tool may be used to enumerate currently enrolled security tokens and wipe a subset + of them. The latter may be combined with the enrollment operation of a new security token, in order to + update or replace enrollments.</para> + + <para>The tool supports only LUKS2 volumes, as it stores token meta-information in the LUKS2 JSON token + area, which is not available in other encryption formats.</para> + </refsect1> + + <refsect1> + <title>Options</title> + + <para>The following options are understood:</para> + + <variablelist> + <varlistentry> + <term><option>--password</option></term> + + <listitem><para>Enroll a regular password/passphrase. This command is mostly equivalent to + <command>cryptsetup luksAddKey</command>, however may be combined with + <option>--wipe-slot=</option> in one call, see below.</para></listitem> + </varlistentry> + + <varlistentry> + <term><option>--recovery-key</option></term> + + <listitem><para>Enroll a recovery key. Recovery keys are most identical to passphrases, but are + computer generated instead of human chosen, and thus have a guaranteed high entropy. The key uses a + character set that is easy to type in, and may be scanned off screen via a QR code.</para></listitem> + </varlistentry> + + <varlistentry> + <term><option>--pkcs11-token-uri=</option><replaceable>URI</replaceable></term> + + <listitem><para>Enroll a PKCS#11 security token or smartcard (e.g. a YubiKey). Expects a PKCS#11 + smart card URI referring to the token. Alternatively the special value <literal>auto</literal> may + be specified, in order to automatically determine the URI of a currently plugged in security token + (of which there must be exactly one). The special value <literal>list</literal> may be used to + enumerate all suitable PKCS#11 tokens currently plugged in. The security token must contain an RSA + key pair which is used to encrypt the randomly generated key that is used to unlock the LUKS2 + volume. The encrypted key is then stored in the LUKS2 JSON token header area.</para> + + <para>In order to unlock a LUKS2 volume with an enrolled PKCS#11 security token, specify the + <option>pkcs11-uri=</option> option in the respective <filename>/etc/crypttab</filename> line:</para> + + <programlisting>myvolume /dev/sda1 - pkcs11-uri=auto</programlisting> + + <para>See + <citerefentry><refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum></citerefentry> for a + more comprehensive example of a <command>systemd-cryptenroll</command> invocation and its matching + <filename>/etc/crypttab</filename> line.</para></listitem> + </varlistentry> + + <varlistentry> + <term><option>--fido2-device=</option><replaceable>PATH</replaceable></term> + + <listitem><para>Enroll a FIDO2 security token that implements the <literal>hmac-secret</literal> + extension (e.g. a YubiKey). Expects a <filename>hidraw</filename> device referring to the FIDO2 + device (e.g. <filename>/dev/hidraw1</filename>). Alternatively the special value + <literal>auto</literal> may be specified, in order to automatically determine the device node of a + currently plugged in security token (of which there must be exactly one). The special value + <literal>list</literal> may be used to enumerate all suitable FIDO2 tokens currently plugged in. Note + that many hardware security tokens that implement FIDO2 also implement the older PKCS#11 + standard. Typically FIDO2 is preferable, given it's simpler to use and more modern.</para> + + <para>In order to unlock a LUKS2 volume with an enrolled FIDO2 security token, specify the + <option>fido2-device=</option> option in the respective <filename>/etc/crypttab</filename> line:</para> + + <programlisting>myvolume /dev/sda1 - fido2-device=auto</programlisting> + + <para>See + <citerefentry><refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum></citerefentry> for a + more comprehensive example of a <command>systemd-cryptenroll</command> invocation and its matching + <filename>/etc/crypttab</filename> line.</para></listitem> + </varlistentry> + + <varlistentry> + <term><option>--tpm2-device=</option><replaceable>PATH</replaceable></term> + + <listitem><para>Enroll a TPM2 security chip. Expects a device node path referring to the TPM2 chip + (e.g. <filename>/dev/tpmrm0</filename>). Alternatively the special value <literal>auto</literal> may + be specified, in order to automatically determine the device node of a currently discovered TPM2 + device (of which there must be exactly one). The special value <literal>list</literal> may be used to + enumerate all suitable TPM2 devices currently discovered.</para> + + <para>In order to unlock a LUKS2 volume with an enrolled TPM2 security chip, specify the + <option>tpm2-device=</option> option in the respective <filename>/etc/crypttab</filename> line:</para> + + <programlisting>myvolume /dev/sda1 - tpm2-device=auto</programlisting> + + <para>See + <citerefentry><refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum></citerefentry> for a + more comprehensive example of a <command>systemd-cryptenroll</command> invocation and its matching + <filename>/etc/crypttab</filename> line.</para> + + <para>Use <option>--tpm2-pcrs=</option> (see below) to configure which TPM2 PCR indexes to bind the + enrollment to.</para></listitem> + </varlistentry> + + <varlistentry> + <term><option>--tpm2-pcrs=</option><arg rep="repeat">PCR</arg></term> + + <listitem><para>Configures the TPM2 PCRs (Platform Configuration Registers) to bind the enrollment + requested via <option>--tpm2-device=</option> to. Takes a comma separated list of numeric PCR indexes + in the range 0…23. If not used, defaults to PCR 7 only. If an empty string is specified, binds the + enrollment to no PCRs at all. PCRs allow binding the enrollment to specific software versions and + system state, so that the enrolled unlocking key is only accessible (may be "unsealed") if specific + trusted software and/or configuration is used.</para></listitem> + + <table> + <title>Well-known PCR Definitions</title> + + <tgroup cols='2' align='left' colsep='1' rowsep='1'> + <colspec colname="pcr" /> + <colspec colname="definition" /> + + <thead> + <row> + <entry>PCR</entry> + <entry>Explanation</entry> + </row> + </thead> + + <tbody> + <row> + <entry>0</entry> + <entry>Core system firmware executable code; changes on firmware updates</entry> + </row> + + <row> + <entry>1</entry> + <entry>Core system firmware data/host platform configuration; typically contains serial and model numbers, changes on basic hardware/CPU/RAM replacements</entry> + </row> + + <row> + <entry>2</entry> + <entry>Extended or pluggable executable code; includes option ROMs on pluggable hardware</entry> + </row> + + <row> + <entry>3</entry> + <entry>Extended or pluggable firmware data; includes information about pluggable hardware</entry> + </row> + + <row> + <entry>4</entry> + <entry>Boot loader; changes on boot loader updates</entry> + </row> + + <row> + <entry>5</entry> + <entry>GPT/Partition table; changes when the partitions are added, modified or removed</entry> + </row> + + <row> + <entry>6</entry> + <entry>Power state events; changes on system suspend/sleep</entry> + </row> + + <row> + <entry>7</entry> + <entry>Secure boot state; changes when UEFI SecureBoot mode is enabled/disabled</entry> + </row> + + <row> + <entry>8</entry> + <entry><citerefentry><refentrytitle>sd-boot</refentrytitle><manvolnum>8</manvolnum></citerefentry> measures the kernel command line in this PCR.</entry> + </row> + </tbody> + </tgroup> + </table> + + </varlistentry> + + <varlistentry> + <term><option>--wipe-slot=</option><arg rep="repeat">SLOT</arg></term> + + <listitem><para>Wipes one or more LUKS2 key slots. Takes a comma separated list of numeric slot + indexes, or the special strings <literal>all</literal> (for wiping all key slots), + <literal>empty</literal> (for wiping all key slots that are unlocked by an empty passphrase), + <literal>password</literal> (for wiping all key slots that are unlocked by a traditional passphrase), + <literal>recovery</literal> (for wiping all key slots that are unlocked by a recovery key), + <literal>pkcs11</literal> (for wiping all key slots that are unlocked by a PKCS#11 token), + <literal>fido2</literal> (for wiping all key slots that are unlocked by a FIDO2 token), + <literal>tpm2</literal> (for wiping all key slots that are unlocked by a TPM2 chip), or any + combination of these strings or numeric indexes, in which case all slots matching either are + wiped. As safety precaution an operation that wipes all slots without exception (so that the volume + cannot be unlocked at all anymore, unless the volume key is known) is refused.</para> + + <para>This switch may be used alone, in which case only the requested wipe operation is executed. It + may also be used in combination with any of the enrollment options listed above, in which case the + enrollment is completed first, and only when successful the wipe operation executed — and the newly + added slot is always excluded from the wiping. Combining enrollment and slot wiping may thus be used to + update existing enrollments:</para> + + <programlisting>systemd-cryptenroll /dev/sda1 --wipe-slot=tpm2 --tpm2-device=auto</programlisting> + + <para>The above command will enroll the TPM2 chip, and then wipe all previously crated TPM2 + enrollments on the LUKS2 volume, leaving only the newly created one. Combining wiping and enrollment + may also be used to replace enrollments of different types, for example for changing from a PKCS#11 + enrollment to a FIDO2 one:</para> + + <programlisting>systemd-cryptenroll /dev/sda1 --wipe-slot=pkcs11 --fido2-device=auto</programlisting> + + <para>Or for replacing an enrolled empty password by TPM2:</para> + + <programlisting>systemd-cryptenroll /dev/sda1 --wipe-slot=empty --tpm2-device=auto</programlisting> + </listitem> + </varlistentry> + + <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> + <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd-cryptsetup@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, + <citerefentry><refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry> + </para> + </refsect1> + +</refentry> diff --git a/man/systemd-cryptsetup-generator.xml b/man/systemd-cryptsetup-generator.xml index 4284f78c4e..e5c193f692 100644 --- a/man/systemd-cryptsetup-generator.xml +++ b/man/systemd-cryptsetup-generator.xml @@ -228,6 +228,7 @@ <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, <citerefentry><refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum></citerefentry>, <citerefentry><refentrytitle>systemd-cryptsetup@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd-cryptenroll</refentrytitle><manvolnum>1</manvolnum></citerefentry>, <citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>, <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry> </para> diff --git a/man/systemd-cryptsetup@.service.xml b/man/systemd-cryptsetup@.service.xml index 216db7467c..c70d6a9d3e 100644 --- a/man/systemd-cryptsetup@.service.xml +++ b/man/systemd-cryptsetup@.service.xml @@ -50,13 +50,14 @@ <orderedlist> <listitem><para>If a key file is explicitly configured (via the third column in - <filename>/etc/crypttab</filename>), a key read from it is used. If a PKCS#11 token is configured - (using the <varname>pkcs11-uri=</varname> option) the key is decrypted before use.</para></listitem> + <filename>/etc/crypttab</filename>), a key read from it is used. If a PKCS#11 token, FIDO2 token or + TPM2 device is configured (using the <varname>pkcs11-uri=</varname>, <varname>fido2-device=</varname>, + <varname>tpm2-device=</varname> options) the key is decrypted before use.</para></listitem> <listitem><para>If no key file is configured explicitly this way, a key file is automatically loaded from <filename>/etc/cryptsetup-keys.d/<replaceable>volume</replaceable>.key</filename> and <filename>/run/cryptsetup-keys.d/<replaceable>volume</replaceable>.key</filename>, if present. Here - too, if a PKCS#11 token is configured, any key found this way is decrypted before + too, if a PKCS#11/FIDO2/TPM2 token/device is configured, any key found this way is decrypted before use.</para></listitem> <listitem><para>If the <varname>try-empty-password</varname> option is specified it is then attempted @@ -77,6 +78,7 @@ <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, <citerefentry><refentrytitle>systemd-cryptsetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>, <citerefentry><refentrytitle>crypttab</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd-cryptenroll</refentrytitle><manvolnum>1</manvolnum></citerefentry>, <citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry> </para> </refsect1> diff --git a/man/systemd-repart.xml b/man/systemd-repart.xml index 16add32b2d..858b5be66d 100644 --- a/man/systemd-repart.xml +++ b/man/systemd-repart.xml @@ -300,12 +300,23 @@ <term><option>--key-file=</option></term> <listitem><para>Takes a file system path. Configures the encryption key to use when setting up LUKS2 - volumes configured with the <varname>Encrypt=</varname> setting in partition files. Should refer to a - regular file containing the key, or an <constant>AF_UNIX</constant> stream socket in the file - system. In the latter case a connection is made to it and the key read from it. If this switch is not - specified the empty key (i.e. zero length key) is used. This behaviour is useful for setting up encrypted - partitions during early first boot that receive their user-supplied password only in a later setup - step.</para></listitem> + volumes configured with the <varname>Encrypt=key-file</varname> setting in partition files. Should + refer to a regular file containing the key, or an <constant>AF_UNIX</constant> stream socket in the + file system. In the latter case a connection is made to it and the key read from it. If this switch + is not specified the empty key (i.e. zero length key) is used. This behaviour is useful for setting + up encrypted partitions during early first boot that receive their user-supplied password only in a + later setup step.</para></listitem> + </varlistentry> + + <varlistentry> + <term><option>--tpm2-device=</option></term> + <term><option>--tpm2-pcrs=</option></term> + + <listitem><para>Configures the TPM2 device and list of PCRs to use for LUKS2 volumes configured with + the <varname>Encrypt=tpm2</varname> option. These options take the same parameters as the identically + named options to + <citerefentry><refentrytitle>systemd-cryptenroll</refentrytitle><manvolnum>1</manvolnum></citerefentry> + and have the same effect on partitions where TPM2 enrollment is requested.</para></listitem> </varlistentry> <xi:include href="standard-options.xml" xpointer="help" /> @@ -314,11 +325,18 @@ </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> <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, <citerefentry><refentrytitle>repart.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>, - <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry> + <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd-cryptenroll</refentrytitle><manvolnum>1</manvolnum></citerefentry> </para> </refsect1> diff --git a/man/tpm2-crypttab.sh b/man/tpm2-crypttab.sh new file mode 100644 index 0000000000..41db2aeddd --- /dev/null +++ b/man/tpm2-crypttab.sh @@ -0,0 +1,10 @@ +# Enroll the TPM2 security chip in the LUKS2 volume, and bind it to PCR 7 +# only. Replace /dev/sdXn by the partition to use (e.g. /dev/sda1). +sudo systemd-cryptenroll --tpm2-device=auto --tpm2-pcrs=7 /dev/sdXn + +# Test: Let's run systemd-cryptsetup to test if this worked. +sudo /usr/lib/systemd/systemd-cryptsetup attach mytest /dev/sdXn - tpm2-device=auto + +# If that worked, let's now add the same line persistently to /etc/crypttab, +# for the future. +sudo bash -c 'echo "mytest /dev/sdXn - tpm2-device=auto" >> /etc/crypttab' diff --git a/man/yubikey-crypttab.sh b/man/yubikey-crypttab.sh index 651246d6a1..05e581b32b 100644 --- a/man/yubikey-crypttab.sh +++ b/man/yubikey-crypttab.sh @@ -1,50 +1,26 @@ -# Make sure no one can read the files we generate but us -umask 077 - # Destroy any old key on the Yubikey (careful!) ykman piv reset -# Generate a new private/public key pair on the device, store the public key in 'pubkey.pem'. +# Generate a new private/public key pair on the device, store the public key in +# 'pubkey.pem'. ykman piv generate-key -a RSA2048 9d pubkey.pem # Create a self-signed certificate from this public key, and store it on the -# device. The "subject" should be an arbitrary string to identify the token in -# the p11tool output below. +# device. The "subject" should be an arbitrary user-chosen string to identify +# the token with. ykman piv generate-certificate --subject "Knobelei" 9d pubkey.pem -# Check if the newly create key on the Yubikey shows up as token in PKCS#11. Have a look at the output, and -# copy the resulting token URI to the clipboard. -p11tool --list-tokens - -# Generate a (secret) random key to use as LUKS decryption key. -dd if=/dev/urandom of=plaintext.bin bs=128 count=1 - -# Encode the secret key also as base64 text (with all whitespace removed) -base64 < plaintext.bin | tr -d '\n\r\t ' > plaintext.base64 - -# Encrypt this newly generated (binary) LUKS decryption key using the public key whose private key is on the -# Yubikey, store the result in /etc/cryptsetup-keys.d/mytest.key, where we'll look for it during boot. -mkdir -p /etc/cryptsetup-keys.d -sudo openssl rsautl -encrypt -pubin -inkey pubkey.pem -in plaintext.bin -out /etc/cryptsetup-keys.d/mytest.key - -# Configure the LUKS decryption key on the LUKS device. We use very low pbkdf settings since the key already -# has quite a high quality (it comes directly from /dev/urandom after all), and thus we don't need to do much -# key derivation. Replace /dev/sdXn by the partition to use (e.g. sda1) -sudo cryptsetup luksAddKey /dev/sdXn plaintext.base64 --pbkdf=pbkdf2 --pbkdf-force-iterations=1000 - -# Now securely delete the plain text LUKS key, we don't need it anymore, and since it contains secret key -# material it should be removed from disk thoroughly. -shred -u plaintext.bin plaintext.base64 - -# We don't need the public key anymore either, let's remove it too. Since this one is not security -# sensitive we just do a regular "rm" here. +# We don't need the public key anymore, let's remove it. Since it is not +# security sensitive we just do a regular "rm" here. rm pubkey.pem -# Test: Let's run systemd-cryptsetup to test if this all worked. The option string should contain the full -# PKCS#11 URI we have in the clipboard; it tells the tool how to decipher the encrypted LUKS key. Note that -# systemd-cryptsetup automatically searches for the encrypted key in /etc/cryptsetup-keys.d/, hence we do -# not need to specify the key file path explicitly here. -sudo systemd-cryptsetup attach mytest /dev/sdXn - 'pkcs11-uri=pkcs11:…' +# Enroll the freshly initialized security token in the LUKS2 volume. Replace +# /dev/sdXn by the partition to use (e.g. /dev/sda1). +sudo systemd-cryptenroll --pkcs11-token-uri=auto /dev/sdXn + +# Test: Let's run systemd-cryptsetup to test if this all worked. +sudo /usr/lib/systemd/systemd-cryptsetup attach mytest /dev/sdXn - pkcs11-uri=auto -# If that worked, let's now add the same line persistently to /etc/crypttab, for the future. -sudo bash -c 'echo "mytest /dev/sdXn - \'pkcs11-uri=pkcs11:…\'" >> /etc/crypttab' +# If that worked, let's now add the same line persistently to /etc/crypttab, +# for the future. +sudo bash -c 'echo "mytest /dev/sdXn - pkcs11-uri=auto" >> /etc/crypttab' |