1 What is WipeFreeSpace?

This program is used for secure erasing of free space on the following partition/filesystem types:

• ext2
• ext3
• ext4
• NTFS
• XFS
• ReiserFSv3
• ReiserFSv4
• FAT12
• FAT16
• FAT32
• MinixFSv1
• MinixFSv2
• JFS
• HFS+
• OCFS

WipeFreeSpace wipes the following things (when supported by the backing library):

• free space (space in unused blocks/clusters)
• free space in partially used blocks (also called the "slack space")
• deleted files’ names and other data that can be used to undelete a file (like the journal)

WipeFreeSpace does NOT decrease the amount of available free space when working.

Normally, when you delete a file, only the information about where the file was is deleted, the file contents stays on the drive. If there’s no writing to that area, the file can physically stay on the drive for a long time. The file contents can be found by e.g. dumping the whole drive with the dd program to a file and looking at the generated image. This may seem not so dangerous, but if you delete confidential information (files with passwords, credit card numbers, encryption keys), any person with physical access to the drive can read that information and use it against you.

ALWAYS USE THE shred (or similar) PROGRAM TO ERASE CONFIDENTIAL DATA.

Sometimes you may delete confidential data the normal way by accident (or have no other choice, because programs like Internet browsers, mail clients, chat clients delete data the normal way). In such case normally you would have to shred the whole partition, which may be a big problem. This is where WipeFreeSpace comes in. This program works in a similar way to the shred program, but instead of shredding regular files, it overwrites (just like shred) the free space on a partition, without doing any harm to existing files. The wiped blocks are NOT marked as used at any stage.

This program also tries to wipe the remaining space in blocks partially used by existing files and wipe deleted elements’ names.

NOTE: The program’s operations are limited by:

• the capabilities of the filesystem-specific library that is used (see Filesystems support)
• the mounting of the filesystem being wiped (filesystems mounted in read+write mode will not be wiped, due to data safety reasons)
• the permissions granted by the operating system, like mounting a read+write filesystem with a loop device in read-only mode still doesn’t allow it to be wiped
• the operating system’s limits (like memory)

THE PROGRAM HAS BEEN TESTED, BUT IT MAY NOW OR LATER CONTAIN ERRORS, WHICH MAY LEAD TO DATA LOSS. ALWAYS BACKUP YOUR DATA BEFORE USING THIS PROGRAM. READ THE LICENSE FOR A WARRANTY (THERE IS NONE).

NOTE: The program will refuse operating if it finds out that it has the suid permission bit set and the owner is root. PLEASE, NEVER do such a thing. If the program is exploited, it can do severe damage to the system. Log in as root and run the program. If you really must run the program as a normal user, set the sgid bit instead and correct the necessary device/file permissions. This is MUCH safer.