media: davinci/vpbe: array underflow in vpbe_enum_outputs()

BugLink: https://bugs.launchpad.net/bugs/1864773

[ Upstream commit b72845ee ]

In vpbe_enum_outputs() we check if (temp_index >= cfg->num_outputs) but
the problem is that "temp_index" can be negative.  This patch changes
the types to unsigned to address this array underflow bug.

Fixes: 66715cdc ("[media] davinci vpbe: VPBE display driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: "Lad, Prabhakar" <prabhakar.csengg@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/media/platform/davinci/vpbe.c

@@ -130,7 +130,7 @@ static int vpbe_enum_outputs(struct vpbe_device *vpbe_dev,
 			     struct v4l2_output *output)
 {
 	struct vpbe_config *cfg = vpbe_dev->cfg;
-	int temp_index = output->index;
+	unsigned int temp_index = output->index;
 
 	if (temp_index >= cfg->num_outputs)
 		return -EINVAL;

include/media/davinci/vpbe.h

@@ -96,7 +96,7 @@ struct vpbe_config {
 	struct encoder_config_info *ext_encoders;
 	/* amplifier information goes here */
 	struct amp_config_info *amp;
-	int num_outputs;
+	unsigned int num_outputs;
 	/* Order is venc outputs followed by LCD and then external encoders */
 	struct vpbe_output *outputs;
 };