[TUHS] History of chown semantics

[Clem Cole]

Right ...  tools like tar(1) called the system call directly,
Which is why the restriction/check in the research family was done in the
OS.
The PWB kernel did not make the check - although V6 did:

http://minnie.tuhs.org/cgi-bin/utree.pl?file=V6/usr/sys/ken/sys4.c

chown()
{
	register *ip;

	if (!suser() || (ip = owner()) == NULL)
		return;
	ip->i_uid = u.u_arg[1].lobyte;
	ip->i_gid = u.u_arg[1].hibyte;
	ip->i_flag =| IUPD;
	iput(ip);
}



Where as: PWB 1.0:
http://minnie.tuhs.org/cgi-bin/utree.pl?file=PWB1/sys/sys/os/sys4.c

chown()
{
	register *ip;

	if ((ip = owner()) == NULL)
		return;
	ip->i_uid = u.u_arg[1].lobyte;
	ip->i_gid = u.u_arg[1].hibyte;
	if(u.u_uid != 0)
		ip->i_mode =& ~(ISUID|ISGID);
	ip->i_flag =| IUPD;
	iput(ip);
}


Clem


On Thu, Jan 9, 2014 at 1:31 PM, Ron Natalie <ron at ronnatalie.com> wrote:

> There's no real point in restricting the chown program if the system call
> remains executable by non-root.
>
> -----Original Message-----
> From: tuhs-bounces at minnie.tuhs.org [mailto:tuhs-bounces at minnie.tuhs.org]
> On
> Behalf Of Dario Niedermann
> Sent: Thursday, January 9, 2014 1:18 PM
> To: tuhs at minnie.tuhs.org
> Subject: Re: [TUHS] History of chown semantics
>
> Il 09/01/2014 alle 15:56, Clem Cole ha scritto:
>
> > I agree with you, I always thought it was crazy [...]
>
> Maybe I'm missing something, but it seems easy enough to make the `chown'
> program only executable by root.
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