Re: $ORIGIN

[Alan Barrett <apb%cequrux.com@localhost>]

On Sun, 26 Jan 2014, David Laight wrote:
> The problem with caching the path is that it might contain 
> symlinks that the user can change - which means that it isn't 
> save to use $ORIGIN in suid binaries.

You can fix that by keeping a reference to the vnode of the 
directory, instead of keeping a string representation of the 
directory name.

> Whereas the kernel has vnode of the directory where the file has 
> found, so should be able to refcount it. An open relative to 
> that vnode is safe (and fast) even for suid programs.

Right.

--apb (Alan Barrett)