lkml.org 
[lkml]   [2010]   [Mar]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH] drivers/media/video: avoid NULL dereference
From: Julia Lawall <julia@diku.dk>

If ov is NULL, it will not be possible to take the lock in the first place,
so move the test up earlier.

The semantic match that finds the problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r exists@
expression E, E1;
identifier f;
statement S1,S3;
iterator iter;
@@

if ((E == NULL && ...) || ...)
{
... when != false ((E == NULL && ...) || ...)
when != true ((E != NULL && ...) || ...)
when != iter(E,...) S1
when != E = E1
(
sizeof(E->f)
|
* E->f
)
... when any
return ...;
}
else S3
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>

---
drivers/media/video/ov511.c | 8 +++-----
1 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/media/video/ov511.c b/drivers/media/video/ov511.c
index e0bce8d..2357218 100644
--- a/drivers/media/video/ov511.c
+++ b/drivers/media/video/ov511.c
@@ -5913,14 +5913,12 @@ ov51x_disconnect(struct usb_interface *intf)

PDEBUG(3, "");

+ if (!ov)
+ return;
+
mutex_lock(&ov->lock);
usb_set_intfdata (intf, NULL);

- if (!ov) {
- mutex_unlock(&ov->lock);
- return;
- }
-
/* Free device number */
ov511_devused &= ~(1 << ov->nr);


\
 
 \ /
  Last update: 2010-03-21 22:33    [W:0.068 / U:0.160 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site