[media] s5k6aa: Fix possible NULL pointer dereference

Make sure __s5k6aa_get_crop_rect() always returns valid pointer,
as it is assumed at the callers.
crop->which is already validated when subdev set_crop and get_crop
callbacks are called from within the v4l2-core. If it ever happens
the crop operations are called directly for some reason in kernel
space, with incorrect crop->which argument, just log it with WARN
and return reference to the TRY crop.

Reported-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Acked-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

diff --git a/drivers/media/i2c/s5k6aa.c b/drivers/media/i2c/s5k6aa.c
index 045ca7f..57cd4fa 100644 (file)
--- a/drivers/media/i2c/s5k6aa.c
+++ b/drivers/media/i2c/s5k6aa.c
@@ -1061,10 +1061,9 @@ __s5k6aa_get_crop_rect(struct s5k6aa *s5k6aa, struct v4l2_subdev_fh *fh,
 {
        if (which == V4L2_SUBDEV_FORMAT_ACTIVE)
                return &s5k6aa->ccd_rect;
-       if (which == V4L2_SUBDEV_FORMAT_TRY)
-               return v4l2_subdev_get_try_crop(fh, 0);
 
-       return NULL;
+       WARN_ON(which != V4L2_SUBDEV_FORMAT_TRY);
+       return v4l2_subdev_get_try_crop(fh, 0);
 }
 
 static void s5k6aa_try_format(struct s5k6aa *s5k6aa,
@@ -1169,12 +1168,10 @@ static int s5k6aa_get_crop(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh,
        struct v4l2_rect *rect;
 
        memset(crop->reserved, 0, sizeof(crop->reserved));
-       mutex_lock(&s5k6aa->lock);
 
+       mutex_lock(&s5k6aa->lock);
        rect = __s5k6aa_get_crop_rect(s5k6aa, fh, crop->which);
-       if (rect)
-               crop->rect = *rect;
-
+       crop->rect = *rect;
        mutex_unlock(&s5k6aa->lock);
 
        v4l2_dbg(1, debug, sd, "Current crop rectangle: (%d,%d)/%dx%d\n",