tar: Privacy

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1 10.2.1 Privacy
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1 
1 Standard privacy concerns apply when using 'tar'.  For example, suppose
1 you are archiving your home directory into a file '/archive/myhome.tar'.
1 Any secret information in your home directory, such as your SSH secret
1 keys, are copied faithfully into the archive.  Therefore, if your home
1 directory contains any file that should not be read by some other user,
1 the archive itself should be not be readable by that user.  And even if
1 the archive's data are inaccessible to untrusted users, its metadata
1 (such as size or last-modified date) may reveal some information about
1 your home directory; if the metadata are intended to be private, the
1 archive's parent directory should also be inaccessible to untrusted
1 users.
1 
1    One precaution is to create '/archive' so that it is not accessible
1 to any user, unless that user also has permission to access all the
1 files in your home directory.
1 
1    Similarly, when extracting from an archive, take care that the
1 permissions of the extracted files are not more generous than what you
1 want.  Even if the archive itself is readable only to you, files
1 extracted from it have their own permissions that may differ.
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