On Wed, Sep 26, 2007 at 08:43:44PM +0930, David Newall wrote:
quoted text
> Olivier Galibert wrote:
> >chroot does not allow you to walk out if you're in.
> 
> You're mistaken.  Or more properly, further use of chroot lets you walk 
> out.  This really has been said before, and before, and before.
> 
>    chroot("subtree");   // enter chroot
>    chdir("/");    // now at subtree
>    chroot("/tmp");   // now outside of chroot

Of course.  chroots are not a stack, they're just a point in the
namespace.  You change it, the conditions apply to the new one.


quoted text
> BSD redefined chroot so that the working directory is set to the new 
> root on subsequent uses of chroot; that's how they solved the bug.

They didn't solve a thing.  fchdir baby.  Unless you want to remove
fchdir.  And mknod.  And mount.  And so many other different syscalls
that I don't even know the list.

  OG.
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