Messages in this thread | | | Date | Sat, 22 Nov 2008 10:56:05 +0100 | From | Takashi Iwai <> | Subject | Re: [PATCH] Fix array overflow in parport_serial.c |
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At Fri, 21 Nov 2008 14:16:21 -0800, Andrew Morton wrote: > > On Thu, 20 Nov 2008 17:35:20 +0100 > Takashi Iwai <tiwai@suse.de> wrote: > > > Subject: [PATCH] Fix array overflow in parport_serial.c > > Please prefer titles in the form > > subsystem identifer: what was done to it > > I renamed this one to > > parport_serial: fix array overflow
Yep, better. Thanks.
> > Date: Thu, 20 Nov 2008 17:35:20 +0100 > > User-Agent: Wanderlust/2.12.0 (Your Wildest Dreams) SEMI/1.14.6 (Maruoka) > > FLIM/1.14.7 (Sanj__) APEL/10.6 Emacs/22.3 > > (x86_64-suse-linux-gnu) MULE/5.0 (SAKAKI) > > > > The netmos_9xx5_combo type assumes that PCI SSID provides always the > > correct value for the number of parallel and serial ports, but there > > are indeed broken devices with wrong numbers, which may result in > > Oops. > > > > This patch simply adds the check of the array range. > > > > Reference: Novell bnc#447067 > > https://bugzilla.novell.com/show_bug.cgi?id=447067 > > > > Signed-off-by: Takashi Iwai <tiwai@suse.de> > > > > --- > > diff --git a/drivers/parport/parport_serial.c b/drivers/parport/parport_serial.c > > index e2e95b3..101ed49 100644 > > --- a/drivers/parport/parport_serial.c > > +++ b/drivers/parport/parport_serial.c > > @@ -70,6 +70,8 @@ static int __devinit netmos_parallel_init(struct pci_dev *dev, struct parport_pc > > * parallel ports and <S> is the number of serial ports. > > */ > > card->numports = (dev->subsystem_device & 0xf0) >> 4; > > + if (card->numports > ARRAY_SIZE(card->addr)) > > hm. ARRAY_SIZE returns an unsigned type so we don't have to worry > about negative values when doing comparisons like this. Not that > card->numports could be negative anyway, but it's always nice to set > readers' minds at rest..
I think changing numports to unsigned is the easiest way.
> > + card->numports = ARRAY_SIZE(card->addr); > > return 0; > > } > > > Should we emit some kind of warning when this is detected? I guess > not, if we're sure that there will never be a situation in which users > find that some of their ports don't work?
I thought of that, too, but wanted to make the change minimum.
Besides that, I'm not sure whether netmos_parallel_init() really works as its description. It changes numports, but it doesn't change the addr[]. In cards[], only one item is defined, thus all of the reset point BAR 0.
I made the patch just to fix the oops, but this code should be fixed in a better way, anyway.
thanks,
Takashi
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