[PATCH] apci: fix NULL deref in video/lcd/brightness

Fix Null pointer deref in video/lcd/brightness
http://bugzilla.kernel.org/show_bug.cgi?id=5571

Signed-off-by: Yu Luming <luming.yu@gmail.com>
Cc: "Brown, Len" <len.brown@intel.com>
Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Chris Wright <chrisw@redhat.com>

diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index e383d6109ae109c6963d43abe7ca71449e554518..00fe1cd6505ae7291568cedbe5c0077af110eba6 100644 (file)
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -813,7 +813,7 @@ acpi_video_device_write_brightness(struct file *file,
 
        ACPI_FUNCTION_TRACE("acpi_video_device_write_brightness");
 
-       if (!dev || count + 1 > sizeof str)
+       if (!dev || !dev->brightness || count + 1 > sizeof str)
                return_VALUE(-EINVAL);
 
        if (copy_from_user(str, buffer, count))