Re: Linux 2.2.18pre21

[Peter Samuelson]

  [I wrote]
> >   mkdir("foo")
> >   chroot("foo")

[H. Peter Anvin]
> BUG: you *MUST* chdir() into the chroot jail before it does you any
> good at all!

No, it wasn't a bug!  It was a demonstration.  The above code is
executed not by the application but by the *attacker* who has managed
to 0wn the existing jail.

Doing the additional chroot("foo") without already being in "foo"
basically replaces the chroot jail you *were* in, so you are now out.

The sequence I posted is just the simplest un-chroot procedure I know,
to explain why chroot cannot sandbox the superuser.

Peter
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
Please read the FAQ at http://www.tux.org/lkml/