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Copyright 2016 Toomas Soome <tsoome@me.com>
Copyright 2013 Nexenta Systems, Inc. All rights reserved.
Copyright (c) 2008, Sun Microsystems, Inc. All Rights Reserved
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.Dd Jun 14, 2016 .Dt LOFIADM 1M .Os .Sh NAME .Nm lofiadm .Nd administer files available as block devices through lofi .Sh SYNOPSIS .Nm .Op Fl r .Op Fl l .Fl a Ar file Op Ar device .Nm .Op Fl r .Fl c .Ar crypto_algorithm .Fl a .Ar file Op Ar device .Nm .Op Fl r .Fl c Ar crypto_algorithm .Fl k Ar raw_key_file .Fl a Ar file Op Ar device .Nm .Op Fl r .Fl c Ar crypto_algorithm .Fl T Ar token_key .Fl a Ar file Op Ar device .Nm .Op Fl r .Fl c Ar crypto_algorithm .Fl T Ar token_key .Fl k Ar wrapped_key_file .Fl a Ar file Op Ar device .Nm .Op Fl r .Fl c Ar crypto_algorithm .Fl e .Fl a Ar file Op Ar device .Nm .Fl C Ar algorithm .Op Fl s Ar segment_size .Ar file .Nm .Fl d Ar file Ns | Ns Ar device .Nm .Fl U Ar file .Nm .Op Ar file Ns | Ns device .Sh DESCRIPTION .Nm administers .Sy lofi , the loopback file driver. .Sy lofi allows a file to be associated with a block device. That file can then be accessed through the block device. This is useful when the file contains an image of some filesystem (such as a floppy or .Sy CD-ROM image), because the block device can then be used with the normal system utilities for mounting, checking or repairing filesystems. See .Xr fsck 1M and .Xr mount 1M .

p Use .Nm to add a file as a loopback device, remove such an association, or print information about the current associations.

p Encryption and compression options are mutually exclusive on the command line. Further, an encrypted file cannot be compressed later, nor can a compressed file be encrypted later.

p In the global zone, .Nm can be used on both the global zone devices and all devices owned by other non-global zones on the system. .Ss Labeled Devices If the command line flag, .Fl l , is used while creating a loopack device, .Sy lofi will create a labeled loopback device, and will generate device links in

a /dev/{dsk,rdsk} directories for partitions or slices.

p Before using these devices, users should create or verify partitioning by using partition management tools such as .Xr format 1M and .Xr fdisk 1M . Once the device has been appropriately partitioned, the labeled device can be used as normal disk to create and mount file systems and to store data. Mappings created by .Nm are not permanent and not persisted by the system. If power is lost or the system is rebooted, then the mappings will need to be created again.

p The partition table requires space from the mapped file. .Sy lofi does not support converting previously created unlabeled loopback device images to labeled loopback devices. If an unlabeled device is used as a labeled device, writing to it will corrupt it. .Sh OPTIONS The following options are supported: l -tag -width Ds t Fl a Ar file Op Ar device Add .Sy file as a block device.

p If .Sy device is not specified, an available device is picked.

p If .Sy device is specified, .Nm attempts to assign it to .Sy file . .Sy device must be available or .Nm will fail. The ability to specify a device is provided for use in scripts that wish to reestablish a particular set of associations. A device may not be specified when using a labeled lofi device. t Fl C Ar {gzip | gzip-N | lzma} Compress the file with the specified compression algorithm.

p The .Sy gzip compression algorithm uses the same compression as the open-source .Sy gzip command. You can specify the .Sy gzip level by using the value gzip-N where N is 6 (fast) or 9 (best compression ratio). Currently, .Sy gzip , without a number, is equivalent to .Sy gzip-6 (which is also the default for the .Sy gzip command).

p .Sy lzma stands for the LZMA (Lempel-Ziv-Markov) compression algorithm.

p Note that you cannot write to a compressed file, nor can you mount a compressed file read/write. t Fl d Ar file Ns | Ns Ar device Remove an association by .Sy file or .Sy device name, if the associated block device is not busy, and deallocates the block device. t Fl l This option should be used with .Fl a option to create labeled loopback device. If created in local zone, the device has to be enabled in zone configuration. t Fl r If the .Fl r option is specified before the .Fl a option, the .Sy device will be opened read-only. t Fl s Ar segment_size The segment size to use to divide the file being compressed. .Sy segment_size can be an integer multiple of 512. t Fl U Ar file Uncompress a compressed file. .El

p The following options are used when the file is encrypted: l -tag -width Ds t Fl c Ar crypto_algorithm Select the encryption algorithm. The algorithm must be specified when encryption is enabled because the algorithm is not stored in the disk image.

p If none of .Fl e , .Fl k , or .Fl T is specified, .Nm prompts for a passphrase, with a minimum length of eight characters, to be entered. The passphrase is used to derive a symmetric encryption key using PKCS#5 PBKD2. t Fl k Ar raw_key_file | Ar wrapped_key_file Path to raw or wrapped symmetric encryption key. If a PKCS#11 object is also given with the .Fl T option, then the key is wrapped by that object. If .Fl T is not specified, the key is used raw. t Fl T Ar token_key The key in a PKCS#11 token to use for the encryption or for unwrapping the key file.

p If .Fl k is also specified, .Fl T identifies the unwrapping key, which must be an RSA private key. t Fl e Generate an ephemeral symmetric encryption key. .El .Sh OPERANDS The following operands are supported: l -tag -width Ds t Ar crypto_algorithm One of: .Sy aes-128-cbc , .Sy aes-192-cbc , .Sy aes-256-cbc , .Sy des3-cbc , .Sy blowfish-cbc . t Ar device Display the file name associated with the block device .Sy device .

p Without arguments, print a list of the current associations. Filenames must be valid absolute pathnames.

p When a file is added, it is opened for reading or writing by root. Any restrictions apply (such as restricted root access over .Sy NFS Ns ). The file is held open until the association is removed. It is not actually accessed until the block device is used, so it will never be written to if the block device is only opened read-only.

p Note that the filename may appear as "?" if it is not possible to resolve the path in the current context (for example, if it's an NFS path in a non-global zone). t Ar file Display the block device associated with .Sy file . t Ar raw_key_file Path to a file of the appropriate length, in bits, to use as a raw symmetric encryption key. t Ar token_key PKCS#11 token object in the format:

p .Ar token_name Ns : Ns Ar manufacturer_id Ns : Ns Ar serial_number Ns : Ns Ar key_label

p All but the key label are optional and can be empty. For example, to specify a token object with only its key label .Sy MylofiKey , use:

p .Fl T Ar ::: Ns Ar MylofiKey t Ar wrapped_key_file Path to file containing a symmetric encryption key wrapped by the RSA private key specified by .Fl T . .El .Sh ENVIRONMENT See .Xr environ 5 for descriptions of the following environment variables that affect the execution of .Nm : .Sy LC_CTYPE , .Sy LC_MESSAGES and .Sy NLSPATH . .Sh EXIT STATUS The following exit values are returned: l -tag -width Ds t Sy 0 Successful completion. t Sy >0 An error occurred. .El .Sh EXAMPLES l -tag -width Ds t Sy Example 1 No Mounting an Existing CD-ROM Image You should ensure that Solaris understands the image before creating the .Sy CD . .Sy lofi allows you to mount the image and see if it works.

p This example mounts an existing .Sy CD-ROM image

f ( Sy sparc.iso Ns ), of the .Sy Red Hat 6.0 CD which was downloaded from the Internet. It was created with the .Sy mkisofs utility from the Internet.

p Use .Nm to attach a block device to it: d -literal # lofiadm -a /home/mike_s/RH6.0/sparc.iso /dev/lofi/1 .Ed

p .Nm picks the device and prints the device name to the standard output. You can run .Nm again by issuing the following command: d -literal # lofiadm Block Device File Options /dev/lofi/1 /home/mike_s/RH6.0/sparc.iso - .Ed

p Or, you can give it one name and ask for the other, by issuing the following command: d -literal # lofiadm /dev/lofi/1 /home/mike_s/RH6.0/sparc.iso .Ed

p Use the .Xr mount 1M command to mount the image: d -literal # mount -F hsfs -o ro /dev/lofi/1 /mnt .Ed

p Check to ensure that Solaris understands the image: d -literal # df -k /mnt Filesystem kbytes used avail capacity Mounted on /dev/lofi/1 512418 512418 0 100% /mnt # ls /mnt ./ RedHat/ doc/ ls-lR rr_moved/ ../ TRANS.TBL dosutils/ ls-lR.gz sbin@ .buildlog bin@ etc@ misc/ tmp/ COPYING boot/ images/ mnt/ usr@ README boot.cat* kernels/ modules/ RPM-PGP-KEY dev@ lib@ proc/ .Ed

p Solaris can mount the CD-ROM image, and understand the filenames. The image was created properly, and you can now create the .Sy CD-ROM with confidence.

p As a final step, unmount and detach the images: d -literal # umount /mnt # lofiadm -d /dev/lofi/1 # lofiadm Block Device File Options .Ed t Sy Example 2 No Mounting a Floppy Image This is similar to the first example.

p Using .Sy lofi to help you mount files that contain floppy images is helpful if a floppy disk contains a file that you need, but the machine which you are on does not have a floppy drive. It is also helpful if you do not want to take the time to use the .Sy dd command to copy the image to a floppy.

p This is an example of getting to .Sy MDB floppy for Solaris on an x86 platform: d -literal # lofiadm -a /export/s28/MDB_s28x_wos/latest/boot.3 /dev/lofi/1 # mount -F pcfs /dev/lofi/1 /mnt # ls /mnt ./ COMMENT.BAT* RC.D/ SOLARIS.MAP* ../ IDENT* REPLACE.BAT* X/ APPEND.BAT* MAKEDIR.BAT* SOLARIS/ # umount /mnt # lofiadm -d /export/s28/MDB_s28x_wos/latest/boot.3 .Ed t Sy Example 3 No Making a Sy UFS No Filesystem on a File Making a .Sy UFS filesystem on a file can be useful, particularly if a test suite requires a scratch filesystem. It can be painful (or annoying) to have to repartition a disk just for the test suite, but you do not have to. You can .Sy newfs a file with .Sy lofi .

p Create the file: d -literal # mkfile 35m /export/home/test .Ed

p Attach it to a block device. You also get the character device that .Sy newfs requires, so .Sy newfs that: d -literal # lofiadm -a /export/home/test /dev/lofi/1 # newfs /dev/rlofi/1 newfs: construct a new file system /dev/rlofi/1: (y/n)? y /dev/rlofi/1: 71638 sectors in 119 cylinders of 1 tracks, 602 sectors 35.0MB in 8 cyl groups (16 c/g, 4.70MB/g, 2240 i/g) super-block backups (for fsck -F ufs -o b=#) at: 32, 9664, 19296, 28928, 38560, 48192, 57824, 67456, .Ed

p Note that .Sy ufs might not be able to use the entire file. Mount and use the filesystem: d -literal # mount /dev/lofi/1 /mnt # df -k /mnt Filesystem kbytes used avail capacity Mounted on /dev/lofi/1 33455 9 30101 1% /mnt # ls /mnt ./ ../ lost+found/ # umount /mnt # lofiadm -d /dev/lofi/1 .Ed t Sy Example 4 No Creating a PC (FAT) File System on a Unix File The following series of commands creates a .Sy FAT file system on a Unix file. The file is associated with a block device created by .Nm . d -literal # mkfile 10M /export/test/testfs # lofiadm -a /export/test testfs /dev/lofi/1 .Ed

p Note use of .Sy rlofi , not .Sy lofi , in following command. d -literal # mkfs -F pcfs -o nofdisk,size=20480 /dev/rlofi/1 Construct a new FAT file system on /dev/rlofi/1: (y/n)? y # mount -F pcfs /dev/lofi/1 /mnt # cd /mnt # df -k . Filesystem kbytes used avail capacity Mounted on /dev/lofi/1 10142 0 10142 0% /mnt .Ed t Sy Example 5 No Compressing an Existing CD-ROM Image The following example illustrates compressing an existing CD-ROM image

f ( Sy solaris.iso Ns ), verifying that the image is compressed, and then uncompressing it. d -literal # lofiadm -C gzip /export/home/solaris.iso .Ed

p Use .Nm to attach a block device to it: d -literal # lofiadm -a /export/home/solaris.iso /dev/lofi/1 .Ed

p Check if the mapped image is compressed: d -literal # lofiadm Block Device File Options /dev/lofi/1 /export/home/solaris.iso Compressed(gzip) /dev/lofi/2 /export/home/regular.iso - .Ed

p Unmap the compressed image and uncompress it: d -literal # lofiadm -d /dev/lofi/1 # lofiadm -U /export/home/solaris.iso .Ed t Sy Example 6 No Creating an Encrypted UFS File System on a File This example is similar to the example of making a UFS filesystem on a file, above.

p Create the file: d -literal # mkfile 35m /export/home/test .Ed

p Attach the file to a block device and specify that the file image is encrypted. As a result of this command, you obtain the character device, which is subsequently used by .Sy newfs : d -literal # lofiadm -c aes-256-cbc -a /export/home/secrets Enter passphrase: My-M0th3r;l0v3s_m3+4lw4ys! (not echoed) Re-enter passphrase: My-M0th3r;l0v3s_m3+4lw4ys! (not echoed) /dev/lofi/1 # newfs /dev/rlofi/1 newfs: construct a new file system /dev/rlofi/1: (y/n)? y /dev/rlofi/1: 71638 sectors in 119 cylinders of 1 tracks, 602 sectors 35.0MB in 8 cyl groups (16 c/g, 4.70MB/g, 2240 i/g) super-block backups (for fsck -F ufs -o b=#) at: 32, 9664, 19296, 28928, 38560, 48192, 57824, 67456, .Ed

p The mapped file system shows that encryption is enabled: d -literal # lofiadm Block Device File Options /dev/lofi/1 /export/home/secrets Encrypted .Ed

p Mount and use the filesystem: d -literal # mount /dev/lofi/1 /mnt # cp moms_secret_*_recipe /mnt # ls /mnt ./ moms_secret_cookie_recipe moms_secret_soup_recipe ../ moms_secret_fudge_recipe moms_secret_stuffing_recipe lost+found/ moms_secret_meatloaf_recipe moms_secret_waffle_recipe # umount /mnt # lofiadm -d /dev/lofi/1 .Ed

p Subsequent attempts to map the filesystem with the wrong key or the wrong encryption algorithm will fail: d -literal # lofiadm -c blowfish-cbc -a /export/home/secrets Enter passphrase: mommy (not echoed) Re-enter passphrase: mommy (not echoed) lofiadm: could not map file /root/lofi: Invalid argument # lofiadm Block Device File Options # .Ed

p Attempts to map the filesystem without encryption will succeed, however attempts to mount and use the filesystem will fail: d -literal # lofiadm -a /export/home/secrets /dev/lofi/1 # lofiadm Block Device File Options /dev/lofi/1 /export/home/secrets - # mount /dev/lofi/1 /mnt mount: /dev/lofi/1 is not this fstype # .Ed .El .Sh SEE ALSO .Xr fdisk 1M , .Xr format 1M , .Xr fsck 1M , .Xr mount 1M , .Xr mount_ufs 1M , .Xr newfs 1M , .Xr attributes 5 , .Xr lofi 7D , .Xr lofs 7FS .Sh NOTES Just as you would not directly access a disk device that has mounted file systems, you should not access a file associated with a block device except through the .Sy lofi file driver. It might also be appropriate to ensure that the file has appropriate permissions to prevent such access.

p The abilities of .Nm , and who can use them, are controlled by the permissions of

a /dev/lofictl . Read-access allows query operations, such as listing all the associations. Write-access is required to do any state-changing operations, like adding an association. As shipped,

a /dev/lofictl is owned by .Sy root , in group .Sy sys , and mode .Sy 0644 , so all users can do query operations but only root can change anything. The administrator can give users write-access, allowing them to add or delete associations, but that is very likely a security hole and should probably only be given to a trusted group.

p When mounting a filesystem image, take care to use appropriate mount options. In particular, the .Sy nosuid mount option might be appropriate for .Sy UFS images whose origin is unknown. Also, some options might not be useful or appropriate, like .Sy logging or .Sy forcedirectio for .Sy UFS . For compatibility purposes, a raw device is also exported along with the block device. For example, .Xr newfs 1M requires one.

p The output of .Nm (without arguments) might change in future releases.