Editing Tar (computing) (section)

===Tarbomb===
{{redirect-distinguish|Tarbomb|zip bomb}}
A '''tarbomb''', in [[Jargon File|hacker slang]], is a tarball containing a large number of items whose contents are written to the current directory or some other existing directory when untarred instead of the directory created by the tarball specifically for the extracted outputs. <ref>{{cite web |title=Tarbomb Definition |language=en |website=[[The Linux Info Project]] |url=https://www.linfo.org/tarbomb.html |access-date=2024-12-12 }}</ref> It is at best an inconvenience to the user, who is obliged to identify and delete a number of files interspersed with the directory's other contents. Such behavior is considered bad etiquette on the part of the archive's creator.

A related problem is the use of [[Path (computing)|absolute path]]s or [[Directory (computing)|parent directory]] references when creating tar files. Files extracted from such archives will often be created in unusual locations outside the working directory and, like a tarbomb, have the potential to overwrite existing files. However, modern versions of FreeBSD and GNU tar do not create or extract absolute paths and parent-directory references by default, unless it is explicitly allowed with the flag {{code|-P}} or the option {{code|--absolute-names}}. The bsdtar program, which is also available on many operating systems and is the default tar implementation on [[macOS|Mac OS X]] v10.6, also does not follow parent-directory references or symbolic links.<ref>{{Cite web|url=https://man.freebsd.org/cgi/man.cgi?query=bsdtar&sektion=1&format=html|title=bsdtar(1)|website=man.freebsd.org}}</ref>
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If a user has only a very old tar available, which does not feature those security measures, these problems can be mitigated by first examining a tar file using the command <code>tar tf archive.tar</code>, which lists the contents and allows to exclude problematic files afterwards. These commands do not extract any files, but display the names of all files in the archive. If any are problematic, the user can create a new empty directory and extract the archive into it—or avoid the tar file entirely. Most graphical tools can display the contents of the archive before extracting them. [[Vim (text editor)|Vim]] can open tar archives and display their contents. [[GNU Emacs]] is also able to open a tar archive and display its contents in a [[dired]] buffer.