[PATCH AUTOSEL 4.14 11/16] media: uvcvideo: Allow entities with no pads

Sasha Levin
2021-02-24T14:17:53Z

From: Ricardo Ribalda <ribalda@chromium.org>

[ Upstream commit 7532dad6634031d083df7af606fac655b8d08b5c ]

Avoid an underflow while calculating the number of inputs for entities
with zero pads.

Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Sasha Levin <sashal@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 5899593dabaf6..aaaee039fb30c 100644
--- a/drivers/media/usb/uvc/uvc_driver.c
+++ b/drivers/media/usb/uvc/uvc_driver.c
@@ -904,7 +904,10 @@ 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);
@@ -920,7 +923,7 @@ 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;
--
2.27.0