On Sun, 13 May 2007, Andrew Morton wrote:
> On Sun, 13 May 2007 12:28:23 +0200 (CEST) Geert Uytterhoeven <[email protected]> wrote:
> > On Mon, 2 Apr 2007, Davide Libenzi wrote:
> > > --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> > > +++ linux-2.6.21-rc5.fds/fs/signalfd.c 2007-04-02 15:06:29.000000000 -0700
> >
> > > +/*
> > > + * Copied from copy_siginfo_to_user() in kernel/signal.c
> > > + */
> > > +static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo,
> > > + siginfo_t const *kinfo)
> > > +{
> > > + long err;
> > > +
> > > + BUILD_BUG_ON(sizeof(struct signalfd_siginfo) != 128);
> > > +
> > > + /*
> > > + * Unused memebers should be zero ...
> > > + */
> > > + err = __clear_user(uinfo, sizeof(*uinfo));
> > ^^^^^^^^^^^^
> >
> > Shouldn't this be `clear_user()'? I don't see any access_ok() calls
> > before this call (I do see them in copy_siginfo_to_user() in
> > kernel/signal.c), but of course I may miss something...
> >
> > I only noticed because m68k doesn't have __clear_user(), as this routine
> > was never needed by generic code before your change.
>
> The vfs does the access_ok() checking on entry to read, write, readv,
> writev, pread and pwrite.
>
> I _think_ that covers everything, in which case all the code which
> implements reading and writing can use the __ functions. We have a lot of
> code which doesn't avail itself of that optimisation though: 12 zillion
> sysfs and proc handlers, for a start.
>
> (I think. I only recently noticed this and might have missed a path).
OK, in that case, I'll add __clear_user().
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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