Re: chmod set user ID query ?
On Friday 21 February 2003 7:33 am, Rob Weir wrote:
> On Tue, Feb 18, 2003 at 08:59:55AM +, Dave Selby wrote:
> > I have a query about chmod. pon is turned on by root, I want it to be
> > turned off by any user. I have looked at several options, sudo,
> > downgrading permissions for kill, gulp, etc etc but decided that for my
> > setup using chmod and setting the user ID for poff would be the best.
> >
> > [EMAIL PROTECTED]:~$ su
> > Password:
> > debian:/home/test# chmod 4755 /usr/bin/poff
> > debian:/home/test# ls -al /usr/bin/poff
> > -rwsr-xr-x1 root root 2772 Dec 10 2001 /usr/bin/poff
> > debian:/home/test#
> > debian:/home/test# pon
> > debian:/home/test#
> > debian:/home/test# exit
> > exit
> > [EMAIL PROTECTED]:~$
> > [EMAIL PROTECTED]:~$ poff
> > /usr/bin/poff: /bin/kill failed. None stopped.
> > [EMAIL PROTECTED]:~$
> > [EMAIL PROTECTED]:~$ which poff
> > /usr/bin/poff
> > [EMAIL PROTECTED]:~$
> >
> > mmm, my ls-al seems to tell me suid has been set, as I understand it the
> > process generated by calling poff from user test should now be run as
> > root. As root it should kill the link started by pon.
> >
> > It fails when poff executes /bin/kill. Any idea why ?
>
> poff is a shell script. setuid scripts are massive security holes, so
> the kernel refuses to honour the set{g,u}id bit on them.
>
> > Does SUID only apply to the called process and not any secondary
> > processes ?
>
> The elevated permissions would be passed along, except that, as I said
> above, the kernel isn't letting the script even start with setuid. My
> suggestion would be to use sudo for this, since it lets you have very
> tightly controlled permissions.
Ah ha that makes sense. I guess a bit of information is a dangerous thing ...
seemed simple !
Many thanks for the info, I realy appreciate it
dave
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Re: chmod set user ID query ?
On Tue, Feb 18, 2003 at 08:59:55AM +, Dave Selby wrote:
> I have a query about chmod. pon is turned on by root, I want it to be turned
> off by any user. I have looked at several options, sudo, downgrading
> permissions for kill, gulp, etc etc but decided that for my setup using chmod
> and setting the user ID for poff would be the best.
>
> test@debian:~$ su
> Password:
> debian:/home/test# chmod 4755 /usr/bin/poff
> debian:/home/test# ls -al /usr/bin/poff
> -rwsr-xr-x1 root root 2772 Dec 10 2001 /usr/bin/poff
> debian:/home/test#
> debian:/home/test# pon
> debian:/home/test#
> debian:/home/test# exit
> exit
> test@debian:~$
> test@debian:~$ poff
> /usr/bin/poff: /bin/kill failed. None stopped.
> test@debian:~$
> test@debian:~$ which poff
> /usr/bin/poff
> test@debian:~$
>
> mmm, my ls-al seems to tell me suid has been set, as I understand it the
> process generated by calling poff from user test should now be run as root.
> As root it should kill the link started by pon.
>
> It fails when poff executes /bin/kill. Any idea why ?
poff is a shell script. setuid scripts are massive security holes, so
the kernel refuses to honour the set{g,u}id bit on them.
> Does SUID only apply to the called process and not any secondary processes ?
The elevated permissions would be passed along, except that, as I said
above, the kernel isn't letting the script even start with setuid. My
suggestion would be to use sudo for this, since it lets you have very
tightly controlled permissions.
--
Rob Weir <[EMAIL PROTECTED]> http://ertius.org/
msg32063/pgp0.pgp
Description: PGP signature
chmod set user ID query ?
I have a query about chmod. pon is turned on by root, I want it to be turned off by any user. I have looked at several options, sudo, downgrading permissions for kill, gulp, etc etc but decided that for my setup using chmod and setting the user ID for poff would be the best. test@debian:~$ su Password: debian:/home/test# chmod 4755 /usr/bin/poff debian:/home/test# ls -al /usr/bin/poff -rwsr-xr-x1 root root 2772 Dec 10 2001 /usr/bin/poff debian:/home/test# debian:/home/test# pon debian:/home/test# debian:/home/test# exit exit test@debian:~$ test@debian:~$ poff /usr/bin/poff: /bin/kill failed. None stopped. test@debian:~$ test@debian:~$ which poff /usr/bin/poff test@debian:~$ mmm, my ls-al seems to tell me suid has been set, as I understand it the process generated by calling poff from user test should now be run as root. As root it should kill the link started by pon. It fails when poff executes /bin/kill. Any idea why ? Does SUID only apply to the called process and not any secondary processes ? Dave -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
