security: avoid calling a NULL function pointer in drivers/video/tvaudio.c
commit 5ba2f67afb02c5302b2898949ed6fc3b3d37dcf1 upstream
NULL function pointers are very bad security wise. This one got caught by
kerneloops.org quite a few times, so it's happening in the field....
Fix is simple, check the function pointer for NULL, like 6 other places
in the same function are already doing.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/media/video/tvaudio.c b/drivers/media/video/tvaudio.c
index 463680b..b59e472 100644
--- a/drivers/media/video/tvaudio.c
+++ b/drivers/media/video/tvaudio.c
@@ -1792,7 +1792,7 @@
break;
case VIDIOC_S_FREQUENCY:
chip->mode = 0; /* automatic */
- if (desc->checkmode) {
+ if (desc->checkmode && desc->setmode) {
desc->setmode(chip,V4L2_TUNER_MODE_MONO);
if (chip->prevmode != V4L2_TUNER_MODE_MONO)
chip->prevmode = -1; /* reset previous mode */
