Re: NMO not setuid-root (Unix-only)

yong321_at_yahoo.com (Yong Huang) wrote in message news:<b3cb12d6.0411300720.3c2ff74d_at_posting.google.com>...
> > > I think it's chmod 6751. If it were 4777, the executable could be
> > > overwritten by anyone, and removed if the directory it is in allows
> > > anyone to change.

Used to be 4777 to set the SUID bit.
Or was it 4755? Can't remember, haven't read the root.sh script in ages.
I hate these binary security bits anyway, always use the "rwx[+-]ugo" syntax: much clearer.

> > In general, a file can be removed if the directory it is in allows you
> > to write in the directory, regardless of the file's permissions. If
> > you have a directory with the sticky-bit set (eg /tmp - usually 1777
> > permission), then you can only remove the file if you own the file, or
> > if you own the directory, or if you're root*.

Interesting. Thanks for that. Didn't know the sticky bit worked that way for directories.

> > But you're right - a SUID anything program with public write
> > permissions is a security disaster;

and in the interest of clarification the reason why should also be explained?
Not everyone here might be aware how easy it is to write a script to impersonate another program.

> Owner bit is set to 7 for convenience when you need to re-make the
> executable (but as you said, the Makefile could just chmod right
> before it does its work).

Hang on: don't you need the owner setup first? The Makefile can't do that, can it? Unless it runs as the owner.

> Other bit is set to 1 so others can't view
> the kernel symbols (by nm). These're all Oracle's decisions, not
> ours...

Aye!... Received on Tue Nov 30 2004 - 15:03:15 CST