Re: copy_from_user() fix

Richard Gooch (rgooch@atnf.csiro.au)
Tue, 25 Aug 1998 17:20:52 +1000


H. Peter Anvin writes:
> Followup to: <199808250429.OAA10383@vindaloo.atnf.CSIRO.AU>
> By author: Richard Gooch <rgooch@atnf.csiro.au>
> In newsgroup: linux.dev.kernel
> >
> > Jamie Lokier writes:
> > > On Tue, Aug 25, 1998 at 01:45:12AM +0100, Jamie Lokier wrote:
> > > > Will I don't agree with the feature either, all we're talking about=
> is
> > > > adding one line to the page fault handler: send_sig(SIGSEGV). Noth=
> ing
> > > > else needs to change, does it?
> > >=20
> > > I just changed my mind.
> > >=20
> > > I bet no applications at all currently check for EFAULT from system
> > > calls, unless they're really weird and are doing it to behave _as if_
> > > they'd received SIGSEGV. Actually I bet they don't bother because ev=
> ery
> > > syscall would need to be wrapped. I'm theorising that this could scr=
> ew
> > > up Wine in some unusual but valid cases.
> >=20
> > Well, you're wrong. I do have applications that explicitely check for
> > EFAULT. I *don't* want them to receive SEGV.
>
> So, what happens if the libc/kernel interface is changed? You're
> screwed, because your code is broken.

I'd then have to ask why Linux has broken applications that work
perfectly well on other systems. I read the man pages on all these
systems and there I see EFAULT.

Didn't someone say Unix98 defines EFAULT? So it looks like we can
herdly blow it away.

Regards,

Richard....

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