linux-kernel - Re: [PATCH] uinput strnlen bugfix

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Date:	Sun, 6 Feb 2011 23:40:17 -0800
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	Aristeu Rozanski <aris@...hedrallabs.org>
Cc:	David Herrmann <dh.herrmann@...glemail.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] uinput strnlen bugfix

On Sun, Feb 06, 2011 at 12:23:17PM -0500, Aristeu Rozanski wrote:
> On Sun, Feb 06, 2011 at 05:57:19PM +0100, David Herrmann wrote:
> > On Sun, Feb 6, 2011 at 5:55 PM, Aristeu Rozanski <aris@...hedrallabs.org> wrote:
> > > and where's the patch? :^)
> > >
> > > --
> > > Aristeu
> > >
> > 
> > ah, embarrasing.., sorry.
> > I attached the patchfile.
> > 
> > David
> 
> > --- old/drivers/input/misc/uinput.c	2011-02-06 17:40:24.951454656 +0100
> > +++ new/drivers/input/misc/uinput.c	2011-02-06 17:41:16.747454654 +0100
> > @@ -372,8 +372,8 @@
> >  
> >  	udev->ff_effects_max = user_dev->ff_effects_max;
> >  
> > -	size = strnlen(user_dev->name, UINPUT_MAX_NAME_SIZE) + 1;
> > -	if (!size) {
> > +	size = strnlen(user_dev->name, UINPUT_MAX_NAME_SIZE);
> > +	if (!size++) {
> >  		retval = -EINVAL;
> >  		goto exit;
> >  	}
> Acked-by: Aristeu Rozanski <aris@...vo.org>
> 

Hmm, not particularly fond with the construct, how about below instead?

Btw, having "Signed-off-by: " from David would be nice.

Thanks.

-- 
Dmitry

Input: uinput - fix setting up device name

From: David Herrmann <dh.herrmann@...glemail.com>

The check for non-empty device name was botched since we tried to account
for extra space for the terminating zero at the same time. Convert to
kstrndup() to avoid this problem.

Acked-by: Aristeu Rozanski <aris@...vo.org>
Signed-off-by: Dmitry Torokhov <dtor@...l.ru>
---

 drivers/input/misc/uinput.c |   13 ++++++-------
 1 files changed, 6 insertions(+), 7 deletions(-)


diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c
index 82542a1..c0888e3 100644
--- a/drivers/input/misc/uinput.c
+++ b/drivers/input/misc/uinput.c
@@ -347,8 +347,7 @@ static int uinput_setup_device(struct uinput_device *udev, const char __user *bu
 {
 	struct uinput_user_dev	*user_dev;
 	struct input_dev	*dev;
-	char			*name;
-	int			i, size;
+	int			i;
 	int			retval;
 
 	if (count != sizeof(struct uinput_user_dev))
@@ -373,19 +372,19 @@ static int uinput_setup_device(struct uinput_device *udev, const char __user *bu
 
 	udev->ff_effects_max = user_dev->ff_effects_max;
 
-	size = strnlen(user_dev->name, UINPUT_MAX_NAME_SIZE) + 1;
-	if (!size) {
+	/* Ensure name is filled in */
+	if (!user_dev->name[0]) {
 		retval = -EINVAL;
 		goto exit;
 	}
 
 	kfree(dev->name);
-	dev->name = name = kmalloc(size, GFP_KERNEL);
-	if (!name) {
+	dev->name = kstrndup(user_dev->name, UINPUT_MAX_NAME_SIZE,
+			     GFP_KERNEL);
+	if (!dev->name) {
 		retval = -ENOMEM;
 		goto exit;
 	}
-	strlcpy(name, user_dev->name, size);
 
 	dev->id.bustype	= user_dev->id.bustype;
 	dev->id.vendor	= user_dev->id.vendor;
--
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