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diff --git a/man/cryptsetup-reencrypt.8 b/man/cryptsetup-reencrypt.8 new file mode 100644 index 0000000..0ebb38c --- /dev/null +++ b/man/cryptsetup-reencrypt.8 @@ -0,0 +1,291 @@ +.TH CRYPTSETUP-REENCRYPT "8" "January 2019" "cryptsetup-reencrypt" "Maintenance Commands" +.SH NAME +cryptsetup-reencrypt - tool for offline LUKS device re-encryption +.SH SYNOPSIS +.B cryptsetup-reencrypt <options> <device> +.SH DESCRIPTION +.PP +Cryptsetup-reencrypt can be used to change reencryption parameters +which otherwise require full on-disk data change (re-encryption). + +You can regenerate \fBvolume key\fR (the real key used in on-disk encryption +unclocked by passphrase), \fBcipher\fR, \fBcipher mode\fR. + +Cryptsetup-reencrypt reencrypts data on LUKS device in-place. During +reencryption process the LUKS device is marked unavailable. + +\fIWARNING\fR: The cryptsetup-reencrypt program is not resistant to hardware +or kernel failures during reencryption (you can lose your data in this case). + +\fIALWAYS BE SURE YOU HAVE RELIABLE BACKUP BEFORE USING THIS TOOL.\fR +.br +The reencryption can be temporarily suspended (by TERM signal or by +using ctrl+c) but you need to retain temporary files named LUKS-<uuid>.[log|org|new]. +LUKS device is unavailable until reencryption is finished though. + +Current working directory must be writable and temporary +files created during reencryption must be present. + +For more info about LUKS see cryptsetup(8). +.PP +.SH OPTIONS +.TP +To start (or continue) re-encryption for <device> use: +.PP +\fIcryptsetup-reencrypt\fR <device> + +\fB<options>\fR can be [\-\-batch-mode, \-\-block-size, \-\-cipher | \-\-keep-key, +\-\-debug, \-\-device-size, \-\-hash, \-\-header, \-\-iter-time | \-\-pbkdf\-force\-iterations, +\-\-key-file, \-\-key-size, \-\-key-slot, \-\-keyfile-offset, \-\-keyfile-size, +\-\-master\-key\-file, \-\-tries, \-\-pbkdf, \-\-pbkdf\-memory, \-\-pbkdf\-parallel, +\-\-progress-frequency, \-\-use-directio, \-\-use-random | \-\-use-urandom, \-\-use-fsync, +\-\-uuid, \-\-verbose, \-\-write-log] + +To encrypt data on (not yet encrypted) device, use \fI\-\-new\fR with combination +with \fI\-\-reduce-device-size\fR or with \fI\-\-header\fR option for detached header. + +To remove encryption from device, use \fI\-\-decrypt\fR. + +For detailed description of encryption and key file options see \fIcryptsetup(8)\fR +man page. +.TP +.B "\-\-batch-mode, \-q" +Suppresses all warnings and reencryption progress output. +.TP +.B "\-\-block-size, \-B \fIvalue\fR" +Use re-encryption block size of <value> in MiB. + +Values can be between 1 and 64 MiB. +.TP +.B "\-\-cipher, \-c" \fI<cipher-spec>\fR +Set the cipher specification string. +.TP +.B "\-\-debug" +Run in debug mode with full diagnostic logs. Debug output +lines are always prefixed by '#'. +.TP +.B "\-\-decrypt" +Remove encryption (decrypt already encrypted device and remove LUKS header). + +\fBWARNING:\fR This is destructive operation and cannot be reverted. +.TP +.B "\-\-device-size \fIsize[units]\fR" +Instead of real device size, use specified value. + +It means that only specified area (from the start of the device +to the specified size) will be reencrypted. + +If no unit suffix is specified, the size is in bytes. + +Unit suffix can be S for 512 byte sectors, K/M/G/T (or KiB,MiB,GiB,TiB) +for units with 1024 base or KB/MB/GB/TB for 1000 base (SI scale). + +\fBWARNING:\fR This is destructive operation. +.TP +.B "\-\-hash, \-h \fI<hash-spec>\fR" +Specifies the hash used in the LUKS1 key setup scheme and volume key digest. + +\fBNOTE:\fR if this parameter is not specified, default hash algorithm is always used +for new LUKS1 device header. + +\fBNOTE:\fR with LUKS2 format this option is only relevant when new keyslot pbkdf algorithm +is set to PBKDF2 (see \fI\-\-pbkdf\fR). +.TP +.B "\-\-header\fR \fI<LUKS header file>\fR" +Use a detached (separated) metadata device or file where the +LUKS header is stored. This option allows one to store ciphertext +and LUKS header on different devices. + +\fBWARNING:\fR There is no check whether the ciphertext device specified +actually belongs to the header given. +If used with \fI\-\-new\fR option, the header file will created (or overwritten). +Use with care. +.TP +.B "\-\-iter-time, \-i \fI<milliseconds>\fR" +The number of milliseconds to spend with PBKDF2 passphrase processing for the +new LUKS header. +.TP +.B "\-\-keep-key" +Do not change encryption key, just reencrypt the LUKS header and keyslots. + +This option can be combined only with \fI\-\-hash\fR, \fI\-\-iter-time\fR, +\fI\-\-pbkdf\-force\-iterations\fR, \fI\-\-pbkdf\fR (LUKS2 only), +\fI\-\-pbkdf\-memory\fR (Argon2i/id and LUKS2 only) and \fI\-\-pbkdf\-parallel\fR +(Argon2i/id and LUKS2 only) options. +.TP +.B "\-\-key-file, \-d \fIname\fR" +Read the passphrase from file. + +\fBWARNING:\fR \-\-key-file option can be used only if there is only one active keyslot, +or alternatively, also if \-\-key-slot option is specified (then all other keyslots +will be disabled in new LUKS device). + +If this option is not used, cryptsetup-reencrypt will ask for all active keyslot +passphrases. +.TP +.B "\-\-key-size, \-s \fI<bits>\fR" +Set key size in bits. The argument has to be a multiple of 8. + +The possible key-sizes are limited by the cipher and mode used. + +If you are increasing key size, there must be enough space in the LUKS header +for enlarged keyslots (data offset must be large enough) or reencryption +cannot be performed. + +If there is not enough space for keyslots with new key size, +you can destructively shrink device with \-\-reduce-device-size option. +.TP +.B "\-\-key-slot, \-S <0-MAX>" +Specify which key slot is used. For LUKS1, max keyslot number is 7. For LUKS2, it's 31. + +\fBWARNING:\fR All other keyslots will be disabled if this option is used. +.TP +.B "\-\-keyfile-offset \fIvalue\fR" +Skip \fIvalue\fR bytes at the beginning of the key file. +.TP +.B "\-\-keyfile-size, \-l" +Read a maximum of \fIvalue\fR bytes from the key file. +Default is to read the whole file up to the compiled-in +maximum. +.TP +.B "\-\-master\-key\-file" +Use new volume (master) key stored in a file. +.TP +.B "\-\-new, \-N" +Create new header (encrypt not yet encrypted device). + +This option must be used together with \-\-reduce-device-size. + +\fBWARNING:\fR This is destructive operation and cannot be reverted. +.TP +.B "\-\-pbkdf" +Set Password-Based Key Derivation Function (PBKDF) algorithm for LUKS keyslot. +The PBKDF can be: \fIpbkdf2\fR, \fIargon2i\fR for Argon2i or \fIargon2id\fR for Argon2id. + +For LUKS1, only \fIpbkdf2\fR is accepted (no need to use this option). +.TP +.B "\-\-pbkdf\-force\-iterations <num>" +Avoid PBKDF benchmark and set time cost (iterations) directly. +.TP +.B "\-\-pbkdf\-memory <number>" +Set the memory cost for PBKDF (for Argon2i/id the number represents kilobytes). +Note that it is maximal value, PBKDF benchmark or available physical memory +can decrease it. +This option is not available for PBKDF2. +.TP +.B "\-\-pbkdf\-parallel <number>" +Set the parallel cost for PBKDF (number of threads, up to 4). +Note that it is maximal value, it is decreased automatically if +CPU online count is lower. +This option is not available for PBKDF2. +.TP +.B "\-\-progress-frequency <seconds>" +Print separate line every <seconds> with reencryption progress. +.TP +.B "\-\-reduce-device-size \fIsize[units]\fR" +Enlarge data offset to specified value by shrinking device size. + +This means that last sectors on the original device will be lost, +ciphertext data will be effectively shifted by specified +number of sectors. + +It can be useful if you e.g. added some space to underlying +partition (so last sectors contains no data). + +For units suffix see \-\-device-size parameter description. + +You cannot shrink device more than by 64 MiB (131072 sectors). + +\fBWARNING:\fR This is destructive operation and cannot be reverted. +Use with extreme care - shrunk filesystems are usually unrecoverable. +.TP +.B "\-\-tries, \-T" +Number of retries for invalid passphrase entry. +.TP +.B "\-\-type <type>" +Use only while encrypting not yet encrypted device (see \-\-new). + +Specify LUKS version when performing in-place encryption. If the parameter +is omitted default value (LUKS1) is used. Type may be one of: \fBluks\fR (default), +\fBluks1\fR or \fBluks2\fR. +.TP +.B "\-\-use-directio" +Use direct-io (O_DIRECT) for all read/write data operations related +to block device undergoing reencryption. + +Useful if direct-io operations perform better than normal buffered +operations (e.g. in virtual environments). +.TP +.B "\-\-use-fsync" +Use fsync call after every written block. This applies for reencryption +log files as well. +.TP +.B "\-\-use-random" +.TP +.B "\-\-use-urandom" +Define which kernel random number generator will be used to create the volume key. +.TP +.B "\-\-uuid" \fI<uuid>\fR +Use only while resuming an interrupted decryption process (see \-\-decrypt). + +To find out what \fI<uuid>\fR to pass look for temporary files LUKS-<uuid>.[|log|org|new] +of the interrupted decryption process. +.TP +.B "\-\-verbose, \-v" +Print more information on command execution. +.TP +.B "\-\-version" +Show the program version. +.TP +.B "\-\-write-log" +Update log file after every block write. This can slow down reencryption +but will minimize data loss in the case of system crash. + +.SH RETURN CODES +Cryptsetup-reencrypt returns 0 on success and a non-zero value on error. + +Error codes are: 1 wrong parameters, 2 no permission, +3 out of memory, 4 wrong device specified, 5 device already exists +or device is busy. +.SH EXAMPLES +.TP +Reencrypt /dev/sdb1 (change volume key) +cryptsetup-reencrypt /dev/sdb1 +.TP +Reencrypt and also change cipher and cipher mode +cryptsetup-reencrypt /dev/sdb1 \-c aes-xts-plain64 +.TP +Add LUKS encryption to not yet encrypted device + +First, be sure you have space added to disk. + +Or alternatively shrink filesystem in advance. +.br +Here we need 4096 512-bytes sectors (enough for 2x128 bit key). + +fdisk \-u /dev/sdb # move sdb1 partition end + 4096 sectors +(or use resize2fs or tool for your filesystem and shrink it) + +cryptsetup-reencrypt /dev/sdb1 \-\-new \-\-reduce-device-size 4096S +.TP +Remove LUKS encryption completely + +cryptsetup-reencrypt /dev/sdb1 \-\-decrypt + +.SH REPORTING BUGS +Report bugs, including ones in the documentation, on +the cryptsetup mailing list at <dm-crypt@saout.de> +or in the 'Issues' section on LUKS website. +Please attach the output of the failed command with the +\-\-debug option added. +.SH AUTHORS +Cryptsetup-reencrypt was written by Milan Broz <gmazyland@gmail.com>. +.SH COPYRIGHT +Copyright \(co 2012-2019 Milan Broz +.br +Copyright \(co 2012-2019 Red Hat, Inc. + +This is free software; see the source for copying conditions. There is NO +warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. +.SH SEE ALSO +The project website at \fBhttps://gitlab.com/cryptsetup/cryptsetup\fR |