Re: [RFC] prevent "dd if=/dev/mem" crash

Pavel Machek
2003-10-19T18:17:57Z

Hi!

> > Old behavior:
> >
> > # dd if=/dev/mem of=/dev/null
> > <unrecoverable machine check>
>
> I recently fixed this for ia32 by changing copy_to_user() to not oops if
> the source address generated a fault. Similarly copy_from_user() returns
> an error if the destination generates a fault.

Are you sure this is not hiding real errors? If you pass wrong
kernel ptr to copy_*_user, it should oops, not mask error with
-EFAULT.
Maybe another copy_user_unsafe should be created?
Pavel
--
Pavel
Written on sharp zaurus, because my Velo1 broke. If you have Velo you don't need...