NAME

       veritysetup - manage dm-verity (block level verification) volumes

SYNOPSIS

       veritysetup <options> <action> <action args>

DESCRIPTION

       Veritysetup is used to configure dm-verity managed device-mapper mappings.

       Device-mapper  verity  target  provides  read-only  transparent integrity checking of block devices using
       kernel crypto API.

       The dm-verity devices are always read-only.

       Veritysetup supports these operations:

       format <data_device> <hash_device>

              Calculates and permanently stores hash verification  data  for  data_device.   Hash  area  can  be
              located on the same device after data if specified by --hash-offset option.

              Note you need to provide root hash string for device verification or activation. Root hash must be
              trusted.

              The  data  or hash device argument can be block device or file image.  If hash device path doesn't
              exist, it will be created as file.

              <options> can be [--hash, --no-superblock, --format, --data-block-size, --hash-block-size, --data-
              blocks, --hash-offset, --salt, --uuid]

       create <name> <data_device> <hash_device> <root_hash>

              Creates a mapping with <name> backed by device <data_device> and using <hash_device> for in-kernel
              verification.

              The <root_hash> is a hexadecimal string.

              <options> can be [--hash-offset, --no-superblock]

              If option --no-superblock is used, you have to use as  the  same  options  as  in  initial  format
              operation.

       verify <data_device> <hash_device> <root_hash>

              Verifies data on data_device with use of hash blocks stored on hash_device.

              This command performs userspace verification, no kernel device is created.

              The <root_hash> is a hexadecimal string.

              <options> can be [--hash-offset, --no-superblock]

              If  option  --no-superblock  is  used,  you  have  to use as the same options as in initial format
              operation.

       remove <name>

              Removes existing mapping <name>.

       status <name>

              Reports status for the active verity mapping <name>.

       dump <hash_device>

              Reports parameters of verity device from on-disk stored superblock.

              <options> can be [--no-superblock]

OPTIONS

       --verbose, -v
              Print more information on command execution.

       --debug
              Run in debug mode with full diagnostic logs. Debug output lines are always prefixed by '#'.

       --no-superblock
              Create or use dm-verity without permanent on-disk superblock.

       --format=number
              Specifies the hash version type.  Format type 0 is original Chrome OS verion.  Format  type  1  is
              current version.

       --data-block-size=bytes
              Used block size for the data device.  (Note kernel supports only page-size as maximum here.)

       --hash-block-size=bytes
              Used block size for the hash device.  (Note kernel supports only page-size as maximum here.)

       --data-blocks=blocks
              Size of data device used in verification.  If not specified, the whole device is used.

       --hash-offset=bytes
              Offset of hash area/superblock on hash_device.  Value must be aligned to disk sector offset.

       --salt=hex string
              Salt used for format or verification.  Format is a hexadecimal string.

       --uuid=UUID
              Use the provided UUID for format command instead of generating new one.

              The UUID must be provided in standard UUID format, e.g. 12345678-1234-1234-1234-123456789abc.

       --version
              Show the program version.

RETURN CODES

       Veritysetup 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.

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.

AUTHORS

       The first implementation of veritysetup was written by Chrome OS authors.

       This version is based on verification code written by Mikulas Patocka <mpatocka@redhat.com> and rewritten
       for libcryptsetup by Milan Broz <gmazyland@gmail.com>.

COPYRIGHT

       Copyright © 2012 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.

SEE ALSO

       The project website at http://code.google.com/p/cryptsetup/

       The verity on-disk format specification available at http://code.google.com/p/cryptsetup/wiki/DMVerity

veritysetup                                         June 2012                                     VERITYSETUP(8)