From: Ricardo Ribalda <riba...@chromium.org>
[ Upstream commit 7532dad6634031d083df7af606fac655b8d08b5c ]
Avoid an underflow while calculating the number of inputs for entities
with zero pads.
Signed-off-by: Ricardo Ribalda <riba...@chromium.org>
Signed-off-by: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+hua...@kernel.org>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
drivers/media/usb/uvc/uvc_driver.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/media/usb/uvc/uvc_driver.c
b/drivers/media/usb/uvc/uvc_driver.c
index 38c73cdbef70..998ce712978a 100644
--- a/drivers/media/usb/uvc/uvc_driver.c
+++ b/drivers/media/usb/uvc/uvc_driver.c
@@ -940,7 +940,10 @@ static struct uvc_entity *uvc_alloc_entity(u16 type, u8 id,
unsigned int i;
extra_size = roundup(extra_size, sizeof(*entity->pads));
- num_inputs = (type & UVC_TERM_OUTPUT) ? num_pads : num_pads - 1;
+ if (num_pads)
+ num_inputs = type & UVC_TERM_OUTPUT ? num_pads : num_pads - 1;
+ else
+ num_inputs = 0;
size = sizeof(*entity) + extra_size + sizeof(*entity->pads) * num_pads
+ num_inputs;
entity = kzalloc(size, GFP_KERNEL);
@@ -956,7 +959,7 @@ static struct uvc_entity *uvc_alloc_entity(u16 type, u8 id,
for (i = 0; i < num_inputs; ++i)
entity->pads[i].flags = MEDIA_PAD_FL_SINK;
- if (!UVC_ENTITY_IS_OTERM(entity))
+ if (!UVC_ENTITY_IS_OTERM(entity) && num_pads)
entity->pads[num_pads-1].flags = MEDIA_PAD_FL_SOURCE;
entity->bNrInPins = num_inputs;
--
2.30.1
