On Fri, 10 Dec 1999, Steve Lee wrote:
> is that the s when you do chmod +x
you mean when you do +s? yes.
chmod 4000 filename will add the setuid bit
chmod +s filename will do the same.
Brian
>
> On Fri, 10 Dec 1999, Brian wrote:
>
> > On Fri, 10 Dec 1999, Steve Lee wrote:
> >
> > >
> > > what does it mean to run something setuid
> >
> > It means that when you run the program, the program changes to the uid of
> > the owner of the program. So if you have a program and its owned by root,
> > and you make it setuid root and executable (chmod 4755), then anyone who
> > runs that program, will be doing the operations of that program as if they
> > were in fact root.
> >
> > Take "passwd" for example:
> >
> > -r-s--x--x 1 root root 22312 Sep 25 10:52 /usr/bin/passwd
> >
> > You know, that as user joeblow, you do not have write permission to
> > /etc/passwd or /etc/shadow. Yet you can run the "passwd" program, and
> > change your passwd (which writes to /etc/passwd and /etc/shadow). How is
> > this possible? Because the program is "setuid root", meaning when it
> > runs, it runs as if it were root. So that even though you cannot write
> > /etc/passwd, the /usr/bin/passwd program CAN since it runs as if it were
> > root.
> >
> > setuid programs can open a whole slew of security problems. Race
> > conditions, incomplete path names, poor enviroment, etc, are just the tip
> > of the iceburg. Lots of caution to anyone who decides to setuid a
> > program.
> >
> > Brian
> >
> >
> > >
> > >
> > > --
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> > > as the Subject.
> > >
> >
> > -----------------------------------------------------
> > Brian Feeny (BF304) [EMAIL PROTECTED]
> > 318-222-2638 x 109 http://www.shreve.net/~signal
> > Network Administrator ShreveNet Inc. (ASN 11881)
> >
> >
> > --
> > To unsubscribe: mail [EMAIL PROTECTED] with "unsubscribe"
> > as the Subject.
> >
>
>
> --
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>
-----------------------------------------------------
Brian Feeny (BF304) [EMAIL PROTECTED]
318-222-2638 x 109 http://www.shreve.net/~signal
Network Administrator ShreveNet Inc. (ASN 11881)
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