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GELI(8)                 FreeBSD System Manager's Manual                GELI(8)

NAME
     geli - control utility for cryptographic GEOM class

SYNOPSIS
     To compile GEOM_ELI into your kernel, place the following lines in your
     kernel configuration file:

           device crypto
           options GEOM_ELI

     Alternately, to load the GEOM_ELI module at boot time, place the
     following line in your loader.conf(5):

           geom_eli_load="YES"

     Usage of the geli(8) utility:

     geli init [-bPv] [-a aalgo] [-e ealgo] [-i iterations] [-K newkeyfile]
          [-l keylen] [-s sectorsize] prov
     geli label - an alias for init
     geli attach [-dprv] [-k keyfile] prov
     geli detach [-fl] prov ...
     geli stop - an alias for detach
     geli onetime [-d] [-a aalgo] [-e ealgo] [-l keylen] [-s sectorsize]
          prov ...
     geli configure [-bB] prov ...
     geli setkey [-pPv] [-i iterations] [-k keyfile] [-K newkeyfile]
          [-n keyno] prov
     geli delkey [-afv] [-n keyno] prov
     geli kill [-av] [prov ...]
     geli backup [-v] prov file
     geli restore [-v] file prov
     geli clear [-v] prov ...
     geli dump [-v] prov ...
     geli list
     geli status
     geli load
     geli unload

DESCRIPTION
     The geli utility is used to configure encryption on GEOM providers.

     The following is a list of the most important features:

           +o   Utilizes the crypto(9) framework, so when there is crypto
               hardware available, geli will make use of it automatically.
           +o   Supports many cryptographic algorithms (currently AES,
               Blowfish, Camellia and 3DES).
           +o   Can optionally perform data authentication (integrity
               verification) utilizing one of the following algorithms:
               HMAC/MD5, HMAC/SHA1, HMAC/RIPEMD160, HMAC/SHA256, HMAC/SHA384
               or HMAC/SHA512.
           +o   Can create a key from a couple of components (user entered
               passphrase, random bits from a file, etc.).
           +o   Allows to encrypt the root partition - the user will be asked
               for the passphrase before the root file system is mounted.
           +o   The passphrase of the user is strengthened with: B. Kaliski,
               PKCS #5: Password-Based Cryptography Specification, Version
               2.0., RFC, 2898.
           +o   Allows to use two independent keys (e.g.  "user key" and
               "company key").
           +o   It is fast - geli performs simple sector-to-sector encryption.
           +o   Allows to backup/restore Master Keys, so when a user has to
               quickly destroy his keys, it is possible to get the data back
               by restoring keys from the backup.
           +o   Providers can be configured to automatically detach on last
               close (so users do not have to remember to detach providers
               after unmounting the file systems).
           +o   Allows to attach a provider with a random, one-time key -
               useful for swap partitions and temporary file systems.
           +o   Allows to verify data integrity (data authentication).

     The first argument to geli indicates an action to be performed:

     init           Initialize provider which needs to be encrypted.  Here you
                    can set up the cryptographic algorithm to use, key length,
                    etc.  The last provider's sector is used to store
                    metadata.

                    Additional options include:

                    -a aalgo        Enable data integrity verification
                                    (authentication) using the given
                                    algorithm.  This will reduce size of
                                    available storage and also reduce speed.
                                    For example, when using 4096 bytes sector
                                    and HMAC/SHA256 algorithm, 89% of the
                                    original provider storage will be
                                    available for use.  Currently supported
                                    algorithms are: HMAC/MD5, HMAC/SHA1,
                                    HMAC/RIPEMD160, HMAC/SHA256, HMAC/SHA384
                                    and HMAC/SHA512.  If the option is not
                                    given, there will be no authentication,
                                    only encryption.

                    -e ealgo        Encryption algorithm to use.  Currently
                                    supported algorithms are: AES, Blowfish,
                                    Camellia and 3DES.  The default is AES.

                    -b              Ask for the passphrase on boot, before the
                                    root partition is mounted.  This makes it
                                    possible to use an encrypted root
                                    partition.  One will still need bootable
                                    unencrypted storage with a /boot/
                                    directory, which can be a CD-ROM disc or
                                    USB pen-drive, that can be removed after
                                    boot.

                    -i iterations   Number of iterations to use with PKCS#5v2.
                                    If this option is not specified, geli will
                                    find the number of iterations which is
                                    equal to 2 seconds of crypto work.  If 0
                                    is given, PKCS#5v2 will not be used.

                    -K newkeyfile   Specifies a file which contains part of
                                    the key.  If newkeyfile is given as -,
                                    standard input will be used.  Here is how
                                    more than one file with a key component
                                    can be used:

                                          # cat key1 key2 key3 | geli init -K - /dev/da0

                    -l keylen       Key length to use with the given
                                    cryptographic algorithm.  If not given,
                                    the default key length for the given
                                    algorithm is used, which is: 128 for AES,
                                    128 for Blowfish, 128 for Camellia and 192
                                    for 3DES.

                    -s sectorsize   Change decrypted provider's sector size.
                                    Increasing sector size allows to increase
                                    performance, because we need to generate
                                    an IV and do encrypt/decrypt for every
                                    single sector - less number of sectors
                                    means less work to do.

                    -P              Do not use passphrase as the key
                                    component.

     attach         Attach the given provider.  The master key will be
                    decrypted using the given passphrase/keyfile and a new
                    GEOM provider will be created using the given provider's
                    name with an ".eli" suffix.

                    Additional options include:

                    -d             If specified, a decrypted provider will be
                                   detached automatically on last close.  This
                                   can help with short memory - user does not
                                   have to remember to detach the provider
                                   after unmounting the file system.  It only
                                   works when the provider was opened for
                                   writing, so it will not work if the file
                                   system on the provider is mounted read-
                                   only.  Probably a better choice is the -l
                                   option for the detach subcommand.

                    -r             Attach read-only provider.  It will not be
                                   opened for writing.

                    -k keyfile     Specifies a file which contains part of the
                                   key.  For more information see the
                                   description of the -K option for the init
                                   subcommand.

                    -p             Do not use passphrase as the key component.

     detach         Detach the given providers, which means remove the devfs
                    entry and clear the keys from memory.

                    Additional options include:

                    -f             Force detach - detach even if the provider
                                   is open.

                    -l             Mark provider to detach on last close.  If
                                   this option is specified, the provider will
                                   not be detached until it is open, but when
                                   it will be closed last time, it will be
                                   automatically detached (even if it was only
                                   opened for reading).

     onetime        Attach the given providers with random, one-time keys.
                    The command can be used to encrypt swap partitions or
                    temporary file systems.

                    Additional options include:

                    -a aalgo        Enable data integrity verification
                                    (authentication).  For more information,
                                    see the description of the init
                                    subcommand.

                    -e ealgo        Encryption algorithm to use.  For more
                                    information, see the description of the
                                    init subcommand.

                    -d              Detach on last close.  Note, the option is
                                    not usable for temporary file systems as
                                    the provider will be detached after
                                    creating the file system on it.  It still
                                    can (and should be) used for swap
                                    partitions.  For more information, see the
                                    description of the attach subcommand.

                    -l keylen       Key length to use with the given
                                    cryptographic algorithm.  For more
                                    information, see the description of the
                                    init subcommand.

                    -s sectorsize   Change decrypted provider's sector size.
                                    For more information, see the description
                                    of the init subcommand.

     configure      Change configuration of the given providers.

                    Additional options include:

                    -b     Set the BOOT flag on the given providers.  For more
                           information, see the description of the init
                           subcommand.

                    -B     Remove the BOOT flag from the given providers.

     setkey         Change or setup (if not yet initialized) selected key.
                    There is one master key, which can be encrypted with two
                    independent user keys.  With the init subcommand, only key
                    number 0 is initialized.  The key can always be changed:
                    for an attached provider, for a detached provider or on
                    the backup file.  When a provider is attached, the user
                    does not have to provide an old passphrase/keyfile.

                    Additional options include:

                    -i iterations  Number of iterations to use with PKCS#5v2.
                                   If 0 is given, PKCS#5v2 will not be used.
                                   To be able to use this option with setkey
                                   subcommand, only one key have to be defined
                                   and this key has to be changed.

                    -k keyfile     Specifies a file which contains part of the
                                   old key.

                    -K newkeyfile  Specifies a file which contains part of the
                                   new key.

                    -n keyno       Specifies the number of the key to change
                                   (could be 0 or 1).  If the provider is
                                   attached and no key number is given, the
                                   key used for attaching the provider will be
                                   changed.  If the provider is detached (or
                                   we are operating on a backup file) and no
                                   key number is given, the key decrypted with
                                   the passphrase/keyfile will be changed.

                    -p             Do not use passphrase as the old key
                                   component.

                    -P             Do not use passphrase as the new key
                                   component.

     delkey         Destroy (overwrite with random data) the selected key.  If
                    one is destroying keys for an attached provider, the
                    provider will not be detached even if all keys will be
                    destroyed.  It can be even rescued with the setkey
                    subcommand.

                    -a             Destroy all keys (does not need -f option).

                    -f             Force key destruction.  This option is
                                   needed to destroy the last key.

                    -n keyno       Specifies the key number.  If the provider
                                   is attached and no key number is given, the
                                   key used for attaching the provider will be
                                   destroyed.  If provider is detached (or we
                                   are operating on a backup file) the key
                                   number has to be given.

     kill           This command should be used in emergency situations.  It
                    will destroy all keys on the given provider and will
                    detach it forcibly (if it is attached).  This is
                    absolutely a one-way command - if you do not have a
                    metadata backup, your data is gone for good.  In case the
                    provider was attached with the -r flag, the keys will not
                    be destroyed, only the provider will be detached.

                    -a             If specified, all currently attached
                                   providers will be killed.

     backup         Backup metadata from the given provider to the given file.

     restore        Restore metadata from the given file to the given
                    provider.

     clear          Clear metadata from the given providers.

     dump           Dump metadata stored on the given providers.

     list           See geom(8).

     status         See geom(8).

     load           See geom(8).

     unload         See geom(8).

     Additional options include:

     -v     Be more verbose.

SYSCTL VARIABLES
     The following sysctl(8) variables can be used to control the behavior of
     the ELI GEOM class.  The default value is shown next to each variable.
     All variables can also be set in /boot/loader.conf.

     kern.geom.eli.debug: 0
             Debug level of the ELI GEOM class.  This can be set to a number
             between 0 and 3 inclusive.  If set to 0, minimal debug
             information is printed.  If set to 3, the maximum amount of debug
             information is printed.

     kern.geom.eli.tries: 3
             Number of times a user is asked for the passphrase.  This is only
             used for providers which should be attached on boot (before the
             root file system is mounted).  If set to 0, attaching providers
             on boot will be disabled.  This variable should be set in
             /boot/loader.conf.

     kern.geom.eli.overwrites: 5
             Specifies how many times the Master-Key will be overwritten with
             random values when it is destroyed.  After this operation it is
             filled with zeros.

     kern.geom.eli.visible_passphrase: 0
             If set to 1, the passphrase entered on boot (before the root file
             system is mounted) will be visible.  This possibility should be
             used with caution as the entered passphrase can be logged and
             exposed via dmesg(8).  This variable should be set in
             /boot/loader.conf.

     kern.geom.eli.threads: 0
             Specifies how many kernel threads should be used for doing
             software cryptography.  Its purpose is to increase performance on
             SMP systems.  If hardware acceleration is available, only one
             thread will be started.  If set to 0, CPU-bound thread will be
             started for every active CPU.

     kern.geom.eli.batch: 0
             When set to 1, can speed-up crypto operations by using batching.
             Batching allows to reduce number of interrupts by responding on a
             group of crypto requests with one interrupt.  The crypto card and
             the driver has to support this feature.

EXIT STATUS
     Exit status is 0 on success, and 1 if the command fails.

EXAMPLES
     Initialize a provider which is going to be encrypted with a passphrase
     and random data from a file on the user's pen drive.  Use 4kB sector
     size.  Attach the provider, create a file system and mount it.  Do the
     work.  Unmount the provider and detach it:

           # dd if=/dev/random of=/mnt/pendrive/da2.key bs=64 count=1
           # geli init -s 4096 -K /mnt/pendrive/da2.key /dev/da2
           Enter new passphrase:
           Reenter new passphrase:
           # geli attach -k /mnt/pendrive/da2.key /dev/da2
           Enter passphrase:
           # dd if=/dev/random of=/dev/da2.eli bs=1m
           # newfs /dev/da2.eli
           # mount /dev/da2.eli /mnt/secret
           ...
           # umount /mnt/secret
           # geli detach da2.eli

     Create an encrypted provider, but use two keys: one for your girlfriend
     and one for you (so there will be no tragedy if she forgets her
     passphrase):

           # geli init /dev/da2
           Enter new passphrase:   (enter your passphrase)
           Reenter new passphrase:
           # geli setkey -n 1 /dev/da2
           Enter passphrase:       (enter your passphrase)
           Enter new passphrase:   (let your girlfriend enter her passphrase ...)
           Reenter new passphrase: (... twice)

     You are the security-person in your company.  Create an encrypted
     provider for use by the user, but remember that users forget their
     passphrases, so back Master Key up with your own random key:

           # dd if=/dev/random of=/mnt/pendrive/keys/`hostname` bs=64 count=1
           # geli init -P -K /mnt/pendrive/keys/`hostname` /dev/ad0s1e
           # geli backup /dev/ad0s1e /mnt/pendrive/backups/`hostname`
           (use key number 0, so the encrypted Master Key by you will be overwritten)
           # geli setkey -n 0 -k /mnt/pendrive/keys/`hostname` /dev/ad0s1e
           (allow the user to enter his passphrase)
           Enter new passphrase:
           Reenter new passphrase:

     Encrypted swap partition setup:

           # dd if=/dev/random of=/dev/ad0s1b bs=1m
           # geli onetime -d -e 3des ad0s1b
           # swapon /dev/ad0s1b.eli

     The example below shows how to configure two providers which will be
     attached on boot (before the root file system is mounted).  One of them
     is using passphrase and three keyfiles and the other is using only a
     keyfile:

           # dd if=/dev/random of=/dev/da0 bs=1m
           # dd if=/dev/random of=/boot/keys/da0.key0 bs=32k count=1
           # dd if=/dev/random of=/boot/keys/da0.key1 bs=32k count=1
           # dd if=/dev/random of=/boot/keys/da0.key2 bs=32k count=1
           # cat /boot/keys/da0.key0 /boot/keys/da0.key1 /boot/keys/da0.key2 | geli init -b -K - da0
           Enter new passphrase:
           Reenter new passphrase:
           # dd if=/dev/random of=/dev/da1s3a bs=1m
           # dd if=/dev/random of=/boot/keys/da1s3a.key bs=128k count=1
           # geli init -b -P -K /boot/keys/da1s3a.key da1s3a

     The providers are initialized, now we have to add those lines to
     /boot/loader.conf:

           geli_da0_keyfile0_load="YES"
           geli_da0_keyfile0_type="da0:geli_keyfile0"
           geli_da0_keyfile0_name="/boot/keys/da0.key0"
           geli_da0_keyfile1_load="YES"
           geli_da0_keyfile1_type="da0:geli_keyfile1"
           geli_da0_keyfile1_name="/boot/keys/da0.key1"
           geli_da0_keyfile2_load="YES"
           geli_da0_keyfile2_type="da0:geli_keyfile2"
           geli_da0_keyfile2_name="/boot/keys/da0.key2"

           geli_da1s3a_keyfile0_load="YES"
           geli_da1s3a_keyfile0_type="da1s3a:geli_keyfile0"
           geli_da1s3a_keyfile0_name="/boot/keys/da1s3a.key"

     Not only configure encryption, but also data integrity verification using
     HMAC/SHA256.

           # geli init -a hmac/sha256 -s 4096 /dev/da0
           Enter new passphrase:
           Reenter new passphrase:
           # geli attach /dev/da0
           Enter passphrase:
           # dd if=/dev/random of=/dev/da0.eli bs=1m
           # newfs /dev/da0.eli
           # mount /dev/da0.eli /mnt/secret

DATA AUTHENTICATION
     geli can verify data integrity when an authentication algorithm is
     specified.  When data corruption/modification is detected, geli will not
     return any data, but instead will return an error (EINVAL).  The offset
     and size of the corrupted data will be printed on the console.  It is
     important to know against which attacks geli provides protection for your
     data.  If data is modified in-place or copied from one place on the disk
     to another even without modification, geli should be able to detect such
     a change.  If an attacker can remember the encrypted data, he can
     overwrite any future changes with the data he owns without notice.  In
     other words geli will not protect your data against replay attacks.

SEE ALSO
     crypto(4), gbde(4), geom(4), loader.conf(5), gbde(8), geom(8), crypto(9)

HISTORY
     The geli utility appeared in FreeBSD 6.0.  Support for Camellia block
     cipher is implemented by Yoshisato Yanagisawa in FreeBSD 7.0.

AUTHORS
     Pawel Jakub Dawidek <pjd@FreeBSD.org>

FreeBSD 11.0-PRERELEASE       September 16, 2006       FreeBSD 11.0-PRERELEASE

NAME | SYNOPSIS | DESCRIPTION | SYSCTL VARIABLES | EXIT STATUS | EXAMPLES | DATA AUTHENTICATION | SEE ALSO | HISTORY | AUTHORS

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