Re: [PATCH] Convert filldir() from __put_user() to unsafe_put_user()
From: Greg KH
Date: Tue Oct 08 2019 - 11:38:38 EST
On Tue, Oct 08, 2019 at 04:29:00PM +0100, Al Viro wrote:
> On Tue, Oct 08, 2019 at 03:14:16PM +0200, Greg KH wrote:
> > On Tue, Oct 08, 2019 at 05:57:12AM +0100, Al Viro wrote:
> > >
> > > OK... BTW, do you agree that the use of access_ok() in
> > > drivers/tty/n_hdlc.c:n_hdlc_tty_read() is wrong? It's used as an early
> > > cutoff, so we don't bother waiting if user has passed an obviously bogus
> > > address. copy_to_user() is used for actual copying there...
> > Yes, it's wrong, and not needed. I'll go rip it out unless you want to?
> I'll throw it into misc queue for now; it has no prereqs and nothing is going
> to depend upon it.
> While looking for more of the same pattern: usb_device_read(). Frankly,
> usb_device_dump() calling conventions look ugly - it smells like it
> would be much happier as seq_file. Iterator would take some massage,
> but that seems to be doable. Anyway, that's a separate story...
That's just a debugfs file, and yes, it should be moved to seq_file. I
think I tried it a long time ago, but given it's just a debugging thing,
I gave up as it wasn't worth it.
But yes, the access_ok() there also seems odd, and should be dropped.