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    SubjectRe: suid bit on directories
    Date
    In article <200205201928.OAA13328@tomcat.admin.navo.hpc.mil>,
    Jesse Pollard <pollard@tomcat.admin.navo.hpc.mil> wrote:
    >And ANY user can put files into YOUR directory. Even files you don't want
    >there. AND you can't tell who did it.

    A setuid bit on a directory doesn't mean it syddenly has
    rwxrwxrwx permissions. You still need permission to create the
    file as usual. Try playing with a setgid directory one day.
    It behaves the same.

    >> Only the owner of the directories can set this flag. There is nothing to
    >> control.
    >
    >Ah - so I can put files into your directory, and suddenly they are owned
    >by you. Remember that the next time you are convicted of piracy with criminal
    >data in your directory.... (DMCA remember - and saying "Those files are not
    >mine" just doesn't cut it, when obviously they have your uid on them; the
    >best you would work them down to is "contributing to piracy").

    It would be stupid to have a setuid directory world writable. You'd
    probably make it group writab;e. Then only people in that group have
    access to create files, so the files aren't anonymous - they were
    created by someone in that group.

    >Also remember what happens when a hard link is created in the directory...
    >The file changes ownership.

    Adding an extra directory entry for a file doesn't change
    the inode (well, the link count is bumped up by one) in any way.

    Mike.
    --
    "Insanity -- a perfectly rational adjustment to an insane world."
    - R.D. Lang

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