Re: Why you should avoid world-writable directories

[kragen () POBOX COM (Kragen Sitaker)]

On Tue, 22 Dec 1998, Gonzo Granzeau wrote:
> As noted from previous sendmail issues, two of the stated problems can be
> solved by doing a correct disk structure.  You cannot create hard links across
> across different partitions.  That way, if you have a /, /usr, /tmp, and a
> /home, you should be okay if it drops it in tmp.  You'd basically have to
> give their program it's own file system.  This still doesn't change the fact
> that it is flawed, but if you are forced to use it...

As djb's recent email to bugtraq points out, this does not solve the
mail destruction problem; you can make a subdirectory in the spool
directory and put your hardlink in there.  That subdirectory is
guaranteed to be on the same partition as the spool directory.

It *does* solve the mail-yourself-a-private-file problem, but I haven't
looked at the VMailer spool-file format enough to figure out whether
there's really a security problem (as djb claims) or not (as Wietse
claims).

--
<kragen () pobox com>       Kragen Sitaker     <http://www.pobox.com/~kragen/>
TurboLinux is outselling NT in Japan's retail software market 10 to 1,
so I hear.
-- http://www.performancecomputing.com/opinions/unixriot/981218.shtml