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From: allbery@ncoast.UUCP (Brandon Allbery)
Newsgroups: comp.os.minix
Subject: Re: SETUID on mkdir and rmdir
Message-ID: <2802@ncoast.UUCP>
Date: Sun, 5-Jul-87 19:34:00 EDT
Article-I.D.: ncoast.2802
Posted: Sun Jul  5 19:34:00 1987
Date-Received: Tue, 7-Jul-87 00:43:51 EDT
References: <1478@ncc.UUCP> <14338@teknowledge-vaxc.ARPA>
Reply-To: allbery@ncoast.UUCP (Brandon Allbery)
Followup-To: comp.os.minix
Organization: Cleveland Public Access UN*X, Cleveland, Oh
Lines: 30

As quoted from <14338@teknowledge-vaxc.ARPA> by mkhaw@teknowledge-vaxc.ARPA (Michael Khaw):
+---------------
| -rwxr-xr-x  1 root     staff       16388 Sep 15  1986 /bin/mkdir
| -rwxr-xr-x  1 root     staff       16384 Sep 15  1986 /bin/rmdir
| 
| So why does SysV need them suid and not 4bsd?
+---------------

NOT AGAIN!!!!!

BSD has system calls mkdir() and rmdir() which deal with "." and "..", and
rmdir() deals with directory not empty.  Therefore, they can be used by non-
root processes.

USG does not.  Directories are created with mknod() and removed with unlink();
neither handles "." or "..".  As a result, mknod() and unlink(dir) are root-
only, so that only programs that know to handle "." and ".." will munge
directories.  (System V r3 apparently has mkdir() now, from what I hear.)

++Brandon
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