From 7f801c41714729f7741a042de839918be2bb56f0 Mon Sep 17 00:00:00 2001
From: H Hartley Sweeten <hartleys@visionengravers.com>
Date: Tue, 12 Jun 2012 11:57:45 -0700
Subject: [PATCH] staging: comedi: sanity check num_subdevices parameter in
 comedi_alloc_subdevices

It's possible for a couple of the comedi drivers to incorrectly call
comedi_alloc_subdevices with num_subdevices = 0. Add a sanity check
before doing the kcalloc.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbot@mev.co.uk>
Cc: Frank Mori Hess <kmhess@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/staging/comedi/drivers.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/staging/comedi/drivers.c b/drivers/staging/comedi/drivers.c
index 979aa0e88997..61161ce8e93f 100644
--- a/drivers/staging/comedi/drivers.c
+++ b/drivers/staging/comedi/drivers.c
@@ -60,6 +60,8 @@ int comedi_alloc_subdevices(struct comedi_device *dev, int num_subdevices)
 {
 	int i;
 
+	if (num_subdevices < 1)
+		return -EINVAL;
 	dev->n_subdevices = num_subdevices;
 	dev->subdevices =
 	    kcalloc(num_subdevices, sizeof(struct comedi_subdevice),