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* [PATCH] staging: line6: toneport.c:  Fix for possible null pointer dereference
@ 2014-05-19 21:39 Rickard Strandqvist
  2014-05-20  7:34 ` Stefan Hajnoczi
  2014-05-20 22:04 ` Dan Carpenter
  0 siblings, 2 replies; 5+ messages in thread
From: Rickard Strandqvist @ 2014-05-19 21:39 UTC (permalink / raw)
  To: Greg Kroah-Hartman, Rashika Kheria
  Cc: Rickard Strandqvist, Stefan Hajnoczi, Dan Carpenter, devel,
	linux-kernel

There is otherwise a risk of a possible null pointer dereference.

Was largely found by using a static code analysis program called cppcheck.

Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
---
 drivers/staging/line6/toneport.c |   14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/staging/line6/toneport.c b/drivers/staging/line6/toneport.c
index af2e7e5..36fe76d 100644
--- a/drivers/staging/line6/toneport.c
+++ b/drivers/staging/line6/toneport.c
@@ -431,11 +431,15 @@ void line6_toneport_disconnect(struct usb_interface *interface)
 {
 	struct usb_line6_toneport *toneport;
 	u16 idProduct;
+	struct snd_line6_pcm *line6pcm;
 
 	if (interface == NULL)
 		return;
 
 	toneport = usb_get_intfdata(interface);
+	if (toneport == NULL)
+		return;
+
 	del_timer_sync(&toneport->timer);
 	idProduct = le16_to_cpu(toneport->line6.usbdev->descriptor.idProduct);
 
@@ -444,13 +448,11 @@ void line6_toneport_disconnect(struct usb_interface *interface)
 		device_remove_file(&interface->dev, &dev_attr_led_green);
 	}
 
-	if (toneport != NULL) {
-		struct snd_line6_pcm *line6pcm = toneport->line6.line6pcm;
+	line6pcm = toneport->line6.line6pcm;
 
-		if (line6pcm != NULL) {
-			line6_pcm_release(line6pcm, LINE6_BITS_PCM_MONITOR);
-			line6_pcm_disconnect(line6pcm);
-		}
+	if (line6pcm != NULL) {
+		line6_pcm_release(line6pcm, LINE6_BITS_PCM_MONITOR);
+		line6_pcm_disconnect(line6pcm);
 	}
 
 	toneport_destruct(interface);
-- 
1.7.10.4


^ permalink raw reply related	[flat|nested] 5+ messages in thread

* Re: [PATCH] staging: line6: toneport.c: Fix for possible null pointer dereference
  2014-05-19 21:39 [PATCH] staging: line6: toneport.c: Fix for possible null pointer dereference Rickard Strandqvist
@ 2014-05-20  7:34 ` Stefan Hajnoczi
  2014-05-20 22:04 ` Dan Carpenter
  1 sibling, 0 replies; 5+ messages in thread
From: Stefan Hajnoczi @ 2014-05-20  7:34 UTC (permalink / raw)
  To: Rickard Strandqvist
  Cc: Greg Kroah-Hartman, Rashika Kheria, Dan Carpenter, devel,
	linux-kernel

On Mon, May 19, 2014 at 11:39 PM, Rickard Strandqvist
<rickard_strandqvist@spectrumdigital.se> wrote:
> There is otherwise a risk of a possible null pointer dereference.
>
> Was largely found by using a static code analysis program called cppcheck.
>
> Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
> ---
>  drivers/staging/line6/toneport.c |   14 ++++++++------
>  1 file changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/staging/line6/toneport.c b/drivers/staging/line6/toneport.c
> index af2e7e5..36fe76d 100644
> --- a/drivers/staging/line6/toneport.c
> +++ b/drivers/staging/line6/toneport.c
> @@ -431,11 +431,15 @@ void line6_toneport_disconnect(struct usb_interface *interface)
>  {
>         struct usb_line6_toneport *toneport;
>         u16 idProduct;
> +       struct snd_line6_pcm *line6pcm;
>
>         if (interface == NULL)
>                 return;
>
>         toneport = usb_get_intfdata(interface);
> +       if (toneport == NULL)
> +               return;
> +
>         del_timer_sync(&toneport->timer);
>         idProduct = le16_to_cpu(toneport->line6.usbdev->descriptor.idProduct);
>
> @@ -444,13 +448,11 @@ void line6_toneport_disconnect(struct usb_interface *interface)
>                 device_remove_file(&interface->dev, &dev_attr_led_green);
>         }
>
> -       if (toneport != NULL) {
> -               struct snd_line6_pcm *line6pcm = toneport->line6.line6pcm;

Didn't look into this but it's the traditional "use before NULL
check".  Can't hurt to fix it.

Reviewed-by: Stefan Hajnoczi <stefanha@gmail.com>

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] staging: line6: toneport.c: Fix for possible null pointer dereference
  2014-05-19 21:39 [PATCH] staging: line6: toneport.c: Fix for possible null pointer dereference Rickard Strandqvist
  2014-05-20  7:34 ` Stefan Hajnoczi
@ 2014-05-20 22:04 ` Dan Carpenter
  1 sibling, 0 replies; 5+ messages in thread
From: Dan Carpenter @ 2014-05-20 22:04 UTC (permalink / raw)
  To: Rickard Strandqvist
  Cc: Greg Kroah-Hartman, Rashika Kheria, devel, Stefan Hajnoczi,
	linux-kernel

On Mon, May 19, 2014 at 11:39:00PM +0200, Rickard Strandqvist wrote:
> There is otherwise a risk of a possible null pointer dereference.
> 
> Was largely found by using a static code analysis program called cppcheck.
> 
> Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>

This one is called from line6_disconnect() and the caller checks that
usb_get_intfdata(interface); returns non-NULL.  So it's messy code but
not a real bug.

For the lustre ones, I don't know if they are real bugs or not.

regards,
dan carpenter


^ permalink raw reply	[flat|nested] 5+ messages in thread

* [PATCH] staging: line6: toneport.c:  Fix for possible null pointer dereference
@ 2014-12-21 22:43 Rickard Strandqvist
  2014-12-22  7:34 ` Stefan Hajnoczi
  0 siblings, 1 reply; 5+ messages in thread
From: Rickard Strandqvist @ 2014-12-21 22:43 UTC (permalink / raw)
  To: Greg Kroah-Hartman, Jerry Snitselaar
  Cc: Rickard Strandqvist, Fabian Mewes, Stefan Hajnoczi, devel,
	linux-kernel

The NULL check was done to late, and there it was a risk
of a possible null pointer dereference.

This was partially found by using a static code analysis program called cppcheck.

Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
---
 drivers/staging/line6/toneport.c |   15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/staging/line6/toneport.c b/drivers/staging/line6/toneport.c
index 6943715..660dc3f 100644
--- a/drivers/staging/line6/toneport.c
+++ b/drivers/staging/line6/toneport.c
@@ -433,12 +433,16 @@ void line6_toneport_reset_resume(struct usb_line6_toneport *toneport)
 void line6_toneport_disconnect(struct usb_interface *interface)
 {
 	struct usb_line6_toneport *toneport;
+	struct snd_line6_pcm *line6pcm;
 	u16 idProduct;
 
 	if (interface == NULL)
 		return;
 
 	toneport = usb_get_intfdata(interface);
+	if (NULL == toneport)
+		return;
+
 	del_timer_sync(&toneport->timer);
 	idProduct = le16_to_cpu(toneport->line6.usbdev->descriptor.idProduct);
 
@@ -447,13 +451,10 @@ void line6_toneport_disconnect(struct usb_interface *interface)
 		device_remove_file(&interface->dev, &dev_attr_led_green);
 	}
 
-	if (toneport != NULL) {
-		struct snd_line6_pcm *line6pcm = toneport->line6.line6pcm;
-
-		if (line6pcm != NULL) {
-			line6_pcm_release(line6pcm, LINE6_BITS_PCM_MONITOR);
-			line6_pcm_disconnect(line6pcm);
-		}
+	line6pcm = toneport->line6.line6pcm;
+	if (line6pcm != NULL) {
+		line6_pcm_release(line6pcm, LINE6_BITS_PCM_MONITOR);
+		line6_pcm_disconnect(line6pcm);
 	}
 
 	toneport_destruct(interface);
-- 
1.7.10.4


^ permalink raw reply related	[flat|nested] 5+ messages in thread

* Re: [PATCH] staging: line6: toneport.c: Fix for possible null pointer dereference
  2014-12-21 22:43 Rickard Strandqvist
@ 2014-12-22  7:34 ` Stefan Hajnoczi
  0 siblings, 0 replies; 5+ messages in thread
From: Stefan Hajnoczi @ 2014-12-22  7:34 UTC (permalink / raw)
  To: Rickard Strandqvist
  Cc: Greg Kroah-Hartman, Jerry Snitselaar, Fabian Mewes, devel,
	linux-kernel

On Sun, Dec 21, 2014 at 10:43 PM, Rickard Strandqvist
<rickard_strandqvist@spectrumdigital.se> wrote:
> The NULL check was done to late, and there it was a risk
> of a possible null pointer dereference.
>
> This was partially found by using a static code analysis program called cppcheck.
>
> Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
> ---
>  drivers/staging/line6/toneport.c |   15 ++++++++-------
>  1 file changed, 8 insertions(+), 7 deletions(-)

Reviewed-by: Stefan Hajnoczi <stefanha@gmail.com>

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2014-12-22  7:34 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
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2014-05-19 21:39 [PATCH] staging: line6: toneport.c: Fix for possible null pointer dereference Rickard Strandqvist
2014-05-20  7:34 ` Stefan Hajnoczi
2014-05-20 22:04 ` Dan Carpenter
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2014-12-21 22:43 Rickard Strandqvist
2014-12-22  7:34 ` Stefan Hajnoczi

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