From: Ricardo Ribalda <ribalda@xxxxxxxxxxxx> [ Upstream commit 7532dad6634031d083df7af606fac655b8d08b5c ] Avoid an underflow while calculating the number of inputs for entities with zero pads. Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx> Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- 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 f353ab569b8e4..def22b7fef9cb 100644 --- a/drivers/media/usb/uvc/uvc_driver.c +++ b/drivers/media/usb/uvc/uvc_driver.c @@ -869,7 +869,10 @@ 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); @@ -885,7 +888,7 @@ 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
