Error in chmod man page

[Benjamin Davenport]

The chmod man page seems to incorrectly report the behavior of the 
sticky bit on directories.


man chmod reports, in part:

STICKY DIRECTORIES
      When  the sticky bit is set on a directory, files in that 
directory may
      be unlinked or renamed only by root or their owner.


This is false (at least for chmod 5.93 and kernel 2.6.15-1.2054_FC5).  
When the sticky bit is set on a directory, files in that directory may 
be unlinked or renamed only by root or their owner OR THE DIRECTORY'S 
OWNER.  The man page would seem to indicate that the sticky bit 
effectively disables rename/unlink capabilities conferred by the write 
bit being set on the directory, when in fact it disables only 
rename/unlink capabilities conferred by the write bit being set for 
group and other on the directory.  This behavior seems correct, since it 
protects the directory owner's ability to delete the directory, even in 
the face of third parties adding files to it, but the man page does not 
mention this behavior.

To test:
mkdir foo
chmod 1775 foo
(as another user with appropriate write permissions) touch foo/bar
(as the first user) rm foo/bar    #SUCCEEDS

The man page would indicate that the first user's rm would fail, since 
the first user is neither the file's owner nor root.

-Ben Davenport