Re: Wiping out setuid programs

[neale () LOWENDALE COM AU (Neale Banks)]

On Sat, 9 Jan 1999, D. J. Bernstein wrote:

[big snip]
> My favorite workaround is to make the binary unreadable; I haven't found
> any vendors silly enough to allow tracing here. Note that this prohibits
> root-squashed NFS mounting for root-owned binaries.

You are proposing that some significant security is obtained by making an
executable file unreadable?

I thought this one was laid to rest last year in the "Dump a mode
--x--x--x binary on Linux 2.0.x" thread, wherein Martin Mares summarised:

> Semantics of unreadable files is well-defined at file level (i.e.,
> it's defined you cannot read() them), but not at any other level. No
> standard guarantees you that contents of such binaries are not
> accessible in any other way

Regards,
Neale.